Science.gov

Sample records for active deformation mechanism

  1. Mechanics of dielectric elastomer-activated deformable transmission grating

    NASA Astrophysics Data System (ADS)

    Wang, Yin; Zhou, Jinxiong; Sun, Wenjie; Wu, Xiaohong; Zhang, Ling

    2014-09-01

    Laminating a thin layer of elastomeric grating on the surface of a prestretched dielectric elastomer (DE) membrane forms a basic design of electrically tunable transmission grating. We analyze the inhomogeneous deformation of a circular multiple-region configuration. Variation of the geometric and material parameters, as well as of the critical condition determined by loss of tension instability, is probed to aid the design of a DE-based deformable grating. The predicted changes in the grating period agree substantially with the experimental results reported by Aschwanden et al (Aschwanden et al 2007 IEEE Photon. Technol. Lett. 19 1090).

  2. Failure and deformation mechanisms at macro- and nano-scales of alkali activated clay

    NASA Astrophysics Data System (ADS)

    Sekhar Das, Pradip; Bhattacharya, Manjima; Chanda, Dipak Kr; Dalui, Srikanta; Acharya, Saikat; Ghosh, Swapankumar; Mukhopadhyay, Anoop Kumar

    2016-06-01

    Here we report two qualitative models on failure and deformation mechanisms at macro- and nano-scales of alkali activated clay (AACL), a material of extraordinary importance as a low cost building material. The models were based on experimental data of compressive failure and nanoindentation response of the AACL materials. A 420% improvement in compressive strength (σ c) of the AACL was achieved after 28 days (d) of curing at room temperature and it correlated well with the decrements in the residual alkali and pH concentrations with the increase in curing time. Based on extensive post-mortem FE-SEM examinations, a schematic model for the compressive failure mechanism of AACL was proposed. In addition, the nanoindentation results of AACL provided the first ever experimental evidence of the presence of nano-scale plasticity and a nano-scale contact deformation resistance that increased with the applied load. These results meant the development of a unique strain tolerant microstructure in the AACL of Indian origin. The implications of these new observations were discussed in terms of a qualitative model based on the deformation of layered clay structure.

  3. Exhumed analogues of seismically active carbonate-bearing thrusts: fault architecture and deformation mechanisms

    NASA Astrophysics Data System (ADS)

    Tesei, T.; Collettini, C.; Viti, C.; Barchi, M. R.

    2012-12-01

    In May 2012 a M = 5.9 earthquake followed by a long aftershock sequence struck the Northern Italy. The sequence occurred at 4-10 km depth within the active front of Northern Apennines Prism and the major events nucleate within, or propagate through, a thick sequence of carbonates. In an inner sector of the Northern Apennines, ancient carbonate-bearing thrusts exposed at the surface, represent exhumed analogues of structures generating seismicity in the active front. Here we document fault architecture and deformation mechanisms of three regional carbonate bearing thrusts with displacement of several kilometers and exhumation in the range of 1-4 km. Fault zone structure and deformation mechanisms are controlled by the lithology of the faulted rocks. In layered limestones and marly-limestones the fault zone is up to 200 m thick and is characterized by intense pressure solution. In massive limestones the deformation generally occurs along thin and sharp slip planes that are in contact with fault portions affected by either cataclasis or pressure solution. SEM and TEM observations show that pressure solution surfaces, made of smectite lamellae, with time tend to form an interconnected network affected by frictional sliding. Sharp slipping planes along massive limestones show localization along Y shear planes that separate an extremely comminuted cataclasites from an almost undeformed protolith. The comparison of the three shear zones depicts a fault zone structure extremely heterogeneous as the result of protolith lithology, geometrical complexities and the presence of inherited structures. We observe the competition between brittle (cataclasis, distributed frictional sliding along phyllosilicates and extremely localized slip within carbonates) and pressure solution processes, that suggest a multi-mode of slip behaviour. Extreme localization along carbonate-bearing Y shear planes is our favorite fault zone feature representing past seismic ruptures along the studied

  4. The role of mechanical heterogeneities in evaporite sequence during deformation initiated by basement fault activity

    NASA Astrophysics Data System (ADS)

    Adamuszek, Marta; Dabrowski, Marcin; Burliga, Stanisław

    2016-04-01

    Kłodawa Salt Structure (KSS) situated in the centre of the Polish Zechstein Basin started to rise above a basement fault in the Early Triassic. Geological studies of the KSS revealed significant differences in the deformation patterns between the PZ1-PZ2 (intensely deformed) and PZ3-PZ4 (less deformed) cycle evaporites. These two older and two younger cycle evaporite complexes are separated by the thick Main Anhydrite (A3) bed. We use numerical simulations to assess the impact of a thick anhydrite bed on intrasalt deformation. In our models, the overburden consists of clastic sediments. A normal fault located in the rigid basement beneath the salt is activated due to model extension. At the same time, the sedimentation process takes place. The evaporites consist of a salt bed intercalated with a thick anhydrite layer of varying position and geometry. To understand the role of anhydrite layer, we run comparative simulations, in which no anhydrite layer is present. In the study, we use our own numerical codes implemented in MATLAB combined with the MILAMIN and MUTILS numerical packages. Our investigations revealed a significant influence of the anhydrite on deformation style in the evaporate series. The supra-anhydrite domain is characterized by weaker deformation and lower rates of salt flow in comparison to the sub-anhydrite domain. The highest contrast in the rate of salt flow between the two domains is observed in the case of the anhydrite layer situated close to the bottom of the salt complex. The thick anhydrite layer additionally diminishes the deformation rate in the supra-anhydrite domain and can lead to detachment of the basement deformation from its overlay. Our numerical simulations showed that the presence of the A3 Main Anhydrite bed could be the dominant factor responsible for the decoupling of deformation in the KSS salt complex.

  5. Deformation mechanisms in experimentally deformed Boom Clay

    NASA Astrophysics Data System (ADS)

    Desbois, Guillaume; Schuck, Bernhard; Urai, Janos

    2016-04-01

    Bulk mechanical and transport properties of reference claystones for deep disposal of radioactive waste have been investigated since many years but little is known about microscale deformation mechanisms because accessing the relevant microstructure in these soft, very fine-grained, low permeable and low porous materials remains difficult. Recent development of ion beam polishing methods to prepare high quality damage free surfaces for scanning electron microscope (SEM) is opening new fields of microstructural investigation in claystones towards a better understanding of the deformation behavior transitional between rocks and soils. We present results of Boom Clay deformed in a triaxial cell in a consolidated - undrained test at a confining pressure of 0.375 MPa (i.e. close to natural value), with σ1 perpendicular to the bedding. Experiments stopped at 20 % strain. As a first approximation, the plasticity of the sample can be described by a Mohr-Coulomb type failure envelope with a coefficient of cohesion C = 0.117 MPa and an internal friction angle ϕ = 18.7°. After deformation test, the bulk sample shows a shear zone at an angle of about 35° from the vertical with an offset of about 5 mm. We used the "Lamipeel" method that allows producing a permanent absolutely plane and large size etched micro relief-replica in order to localize and to document the shear zone at the scale of the deformed core. High-resolution imaging of microstructures was mostly done by using the BIB-SEM method on key-regions identified after the "Lamipeel" method. Detailed BIB-SEM investigations of shear zones show the following: the boundaries between the shear zone and the host rock are sharp, clay aggregates and clastic grains are strongly reoriented parallel to the shear direction, and the porosity is significantly reduced in the shear zone and the grain size is smaller in the shear zone than in the host rock but there is no evidence for broken grains. Comparison of microstructures

  6. Preferred orientation in experimentally deformed stishovite: implications for deformation mechanisms

    NASA Astrophysics Data System (ADS)

    Kaercher, P. M.; Zepeda-Alarcon, E.; Prakapenka, V.; Kanitpanyacharoen, W.; Smith, J.; Sinogeikin, S. V.; Wenk, H. R.

    2014-12-01

    The crystal structure of the high pressure SiO2 polymorph stishovite has been studied in detail, yet little is known about its deformation mechanisms. Information about how stishovite deforms under stress is important for understanding subduction of quartz-bearing crustal rocks into the mantle. Particularly, stishovite is elastically anisotropic and thus development of crystallographic preferred orientation (CPO) during deformation may contribute to seismic anomalies in the mantle. We converted a natural sample of flint to stishovite in a laser heated diamond anvil cell and compressed the stishovite aggregate up to 38 GPa. Diffraction patterns were collected in situ in radial geometry at the Advanced Light Source (ALS) and the Advanced Photon Source (APS) to examine development of CPO during deformation. We find that (001) poles preferentially align with the compression direction and infer deformation mechanisms leading to the observed CPO with visco-plastic self consistent (VPSC) polycrystal plasticity models. Our results show pyramidal and basal slip are most likely active at high pressure and ambient temperature, in agreement with transmission electron microscopy (TEM) studies of rutile (TiO2) and paratellurite (TeO2), which are isostructural to stishovite. Conversely other TEM studies of stishovite done at higher temperature suggest dominant prismatic slip. This indicates that a variety of slip systems may be active in stishovite, depending on conditions. As a result, stishovite's contribution to the seismic signature in the mantle may vary as a function of pressure and temperature and thus depth.

  7. Mechanics of Magnetostrictive Thin Film Deformation and its Application in Active X-ray Optics

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoli

    High quality imaging system of telescopes in astronomy requires innovations to remove or correct the mid-spatial frequency (MSF) ripples on the mirror surface of lightweight optics. When the telescope is sent to the space, its launch mass is the key point to limit its collecting area. Therefore, the lightweight optics (100-150 mum thick electroplated nickel/cobalt, or 200-400 mum thick glass) is considered to be employed. However, the surface profile of the thin optical surface can't be polished to extremely high accuracy. Instead, the profile is expected to be corrected by applying voltage or magnetic field to drive the coating of smart materials (piezo or magnetostrictive materials) on the back side of the mirrors. During the process, the surface profile correction by the local stress on the 2-d surface is challenging. Both the measurements and the theoretical prediction of the surface profiles after correction are investigated. As a first step in the development of tools to predict the deformation of the coated glass strip samples (20x5x0.1 mm), one commercial magnetically smart material (MSM) was deposited on the samples by the magnetron sputtering method. One experimental setup was established to measure the deflections of these coated samples under an external magnetic field by Zygo NewView white light interferometry (WLI). These deflections agreed well with the results from the developed analytical and numerical analysis under various magnetic field strengths. In the further research, more efforts were made to analyze the full three-dimensional deformation behavior of MSM thin films on a square glass sample (50x50x0.2 mm). With the magnetic field applied, the 2-d surface profile of the coated glass sample was measured by WLI. To better study the deformation of the sample coated with MSMs, a finite element method (FEM) and a theoretical model were developed to predict the deformation of the sample with local misfit strains. The results calculated form the FEM

  8. A review about the mechanisms associated with active deformation, regional uplift and subsidence in southern South America

    NASA Astrophysics Data System (ADS)

    Folguera, Andrés; Gianni, Guido; Sagripanti, Lucía; Rojas Vera, Emilio; Novara, Iván; Colavitto, Bruno; Alvarez, Orlando; Orts, Darío; Tobal, Jonathan; Giménez, Mario; Introcaso, Antonio; Ruiz, Francisco; Martínez, Patricia; Ramos, Victor A.

    2015-12-01

    A broad range of processes acted simultaneously during the Quaternary producing relief in the Andes and adjacent foreland, from the Chilean coast, where the Pacific Ocean floor is being subducted beneath South American, to the Brazilian and the Argentinean Atlantic platform area. This picture shows to be complex and responds to a variety of processes. The Geoid exemplifies this spectrum of uplift mechanisms, since it reflects an important change at 35°S along the Andes and the foreland that could be indicating the presence of dynamic forces modeling the topography with varying intensity through the subduction margin. On the other hand, mountains uplifted in the Atlantic margin, along a vast sector of the Brazilian Atlantic coast and inland regions seem to be created at the area where the passive margin has been hyper-extended and consequently mechanically debilitated and the forearc region shifts eastwardly at a similar rate than the westward advancing continent. Therefore the forearc at the Arica latitudes can be considered as relatively stationary and dynamically sustained by a perpendicular-to-the-margin asthenospheric flow that inhibits trench roll back, determining a highly active orogenic setting at the eastern Andes in the Subandean region. To the south, the Pampean flat subduction zone creates particular conditions for deformation and rapid propagation of the orogenic front producing a high-amplitude orogen. In the southern Central and Patagonian Andes, mountain (orogenic) building processes are attenuated, becoming dominant other mechanisms of exhumation such as the i) impact of mantle plumes originated in the 660 km mantle transition, ii) the ice-masse retreat from the Andes after the Pleistocene producing an isostatic rebound, iii) the dynamic topography associated with the opening of an asthenospheric window during the subduction of the Chile ridge and slab tearing processes, iv) the subduction of oceanic swells linked to transform zones and v) the

  9. Dislocation Mechanics of High-Rate Deformations

    NASA Astrophysics Data System (ADS)

    Armstrong, Ronald W.; Li, Qizhen

    2015-10-01

    Four topics associated with constitutive equation descriptions of rate-dependent metal plastic deformation behavior are reviewed in honor of previous research accomplished on the same issues by Professor Marc Meyers along with colleagues and students, as follow: (1) increasing strength levels attributed to thermally activated dislocation migration at higher loading rates; (2) inhomogeneous adiabatic shear banding; (3) controlling mechanisms of deformation in shock as compared with shock-less isentropic compression experiments and (4) Hall-Petch-based grain size-dependent strain rate sensitivities exhibited by nanopolycrystalline materials. Experimental results are reviewed on the topics for a wide range of metals.

  10. Microstructures and deformation mechanisms of experimentally deformed gabbro

    NASA Astrophysics Data System (ADS)

    Zhou, Yongsheng; He, Changrong

    2015-04-01

    The natural gabbro samples were deformed at temperature ranging from 700 to 1150 °C with strain rate steps of 1 × 10-4, 2.5 × 10-5, 6.3 × 10-6 s-1. The mechanical data show that sample experiences gradual transition from semi-brittle flow to plastic flow, corresponding to a systematically decreasing stress exponent n with the increasing temperature ranging from 16.5 to 4.1 (He et al. Sci China (D) 46(7):730-742, 2003). We investigate microstructures and deformation mechanisms of experimentally deformed gabbro under transmission electron microscope in this study. For low temperature of 700 °C to 950 °C, the deformation is mainly accommodated with dislocation glide and mechanical twinning, corresponding to stress exponent lager than 5, which means semi-brittle deformation. Whereas with higher temperature up to 1000 °C-1150 °C, the deformation is accommodated mainly with dislocation glide and climb corresponding to stress exponent of 4.1, which means plastic deformation. Evidence of dislocation climb has been found as dislocation walls in plagioclase. The observed slip system in plagioclase is (001)1/2[110] and that in clinopyroxene are (100)[001] and (010)[001]. The (010)[001] slip system in clinopyroxene is newly found in this work. Melt was found at temperature of 950 °C-1050 °C. The melt glass distributed both in melt thin film between two grain boundaries and melt tubules of triangular along three grain boundaries at temperature of 950 °C-1000 °C. The melt triangular interconnected to the melt film at temperature of 1050 °C-1150 °C, where the melt chemical composition differentiated into iron-rich dark dots and silicate-rich matrix.

  11. Sequential growth of deformation bands in carbonate grainstones in the hangingwall of an active growth fault: Implications for deformation mechanisms in different tectonic regimes

    NASA Astrophysics Data System (ADS)

    Rotevatn, Atle; Thorsheim, Elin; Bastesen, Eivind; Fossmark, Heidi S. S.; Torabi, Anita; Sælen, Gunnar

    2016-09-01

    Deformation bands in porous sandstones have been extensively studied for four decades, whereas comparatively less is known about deformation bands in porous carbonate rocks, particularly in extensional settings. Here, we investigate porous grainstones of the Globigerina Limestone Formation in Malta, which contain several types of deformation bands in the hangingwall of the Maghlaq Fault: (i) bed-parallel pure compaction bands (PCB); (ii) pressure solution-dominated compactive shear bands (SCSB) and iii) cataclasis-dominated compactive shear bands (CCSB). Geometric and kinematic analyses show that the bands formed sequentially in the hangingwall of the evolving Maghlaq growth fault. PCBs formed first due to fault-controlled subsidence and vertical loading; a (semi-)tectonic control on PCB formation is thus documented for the first time in an extensional setting. Pressure solution (dominating SCSBs) and cataclasis (dominating CCSBs) appear to have operated separately, and not in concert. Our findings therefore suggest that, in some carbonate rocks, cataclasis within deformation bands may develop irrespective of whether pressure solution processes are involved. We suggest this may be related to stress state, and that whereas pressure solution is a significant facilitator of grain size reduction in contractional settings, grain size reduction within deformation bands in extensional settings is less dependent on pressure solution processes.

  12. Dislocations: 75 years of Deformation Mechanisms

    NASA Technical Reports Server (NTRS)

    Schneider, Judy

    2009-01-01

    The selection of papers presented in this section reflect on themes to be explored at the "Dislocations: 75 years of Deformation Mechanisms" Symposium to be held at the Annual 2009 TMS meeting. The symposium was sponsored by the Mechanical Behavior of Materials Committee to give tribute to the evolution of a concept that has formed the basis of our mechanistic understanding of how crystalline solids plastically deform and how they fail.

  13. Improving the mechanical properties of Zr-based bulk metallic glass by controlling the activation energy for β-relaxation through plastic deformation

    SciTech Connect

    Adachi, Nozomu; Todaka, Yoshikazu Umemoto, Minoru; Yokoyama, Yoshihiko

    2014-09-29

    The mechanism of plastic deformation in bulk metallic glasses (BMGs) is widely believed to be based on a shear transformation zone (STZ). This model assumes that a shear-induced atomic rearrangement occurs at local clusters that are a few to hundreds of atoms in size. It was recently postulated that the potential energy barrier for STZ activation, W{sub STZ}, calculated using the cooperative shear model, is equivalent to the activation energy for β-relaxation, E{sub β}. This result suggested that the fundamental process for STZ activation is the mechanically activated β-relaxation. Since the E{sub β} value and the glass transition temperature T{sub g} of BMGs have a linear relation, that is, because E{sub β} ≈ 26RT{sub g}, the composition of the BMG determines the ease with which the STZ can be activated. Enthalpy relaxation experiments revealed that the BMG Zr{sub 50}Cu{sub 40}Al{sub 10} when deformed by high-pressure torsion (HPT) has a lower E{sub β} of 101 kJ/mol. The HPT-processed samples accordingly exhibited tensile plastic elongation (0.34%) and marked decreases in their yield strength (330 MPa). These results suggest that mechanically induced structural defects (i.e., the free volume and the anti-free volume) effectively act to reduce W{sub STZ} and increase the number of STZs activated during tensile testing to accommodate the plastic strain without requiring a change in the composition of the BMG. Thus, this study shows quantitatively that mechanically induced structural defects can overcome the compositional limitations of E{sub β} (or W{sub STZ}) and result in improvements in the mechanical properties of the BMG.

  14. Improving the mechanical properties of Zr-based bulk metallic glass by controlling the activation energy for β-relaxation through plastic deformation

    NASA Astrophysics Data System (ADS)

    Adachi, Nozomu; Todaka, Yoshikazu; Yokoyama, Yoshihiko; Umemoto, Minoru

    2014-09-01

    The mechanism of plastic deformation in bulk metallic glasses (BMGs) is widely believed to be based on a shear transformation zone (STZ). This model assumes that a shear-induced atomic rearrangement occurs at local clusters that are a few to hundreds of atoms in size. It was recently postulated that the potential energy barrier for STZ activation, WSTZ, calculated using the cooperative shear model, is equivalent to the activation energy for β-relaxation, Eβ. This result suggested that the fundamental process for STZ activation is the mechanically activated β-relaxation. Since the Eβ value and the glass transition temperature Tg of BMGs have a linear relation, that is, because Eβ ≈ 26RTg, the composition of the BMG determines the ease with which the STZ can be activated. Enthalpy relaxation experiments revealed that the BMG Zr50Cu40Al10 when deformed by high-pressure torsion (HPT) has a lower Eβ of 101 kJ/mol. The HPT-processed samples accordingly exhibited tensile plastic elongation (0.34%) and marked decreases in their yield strength (330 MPa). These results suggest that mechanically induced structural defects (i.e., the free volume and the anti-free volume) effectively act to reduce WSTZ and increase the number of STZs activated during tensile testing to accommodate the plastic strain without requiring a change in the composition of the BMG. Thus, this study shows quantitatively that mechanically induced structural defects can overcome the compositional limitations of Eβ (or WSTZ) and result in improvements in the mechanical properties of the BMG.

  15. Highly deformable bones: unusual deformation mechanisms of seahorse armor.

    PubMed

    Porter, Michael M; Novitskaya, Ekaterina; Castro-Ceseña, Ana Bertha; Meyers, Marc A; McKittrick, Joanna

    2013-06-01

    Multifunctional materials and devices found in nature serve as inspiration for advanced synthetic materials, structures and robotics. Here, we elucidate the architecture and unusual deformation mechanisms of seahorse tails that provide prehension as well as protection against predators. The seahorse tail is composed of subdermal bony plates arranged in articulating ring-like segments that overlap for controlled ventral bending and twisting. The bony plates are highly deformable materials designed to slide past one another and buckle when compressed. This complex plate and segment motion, along with the unique hardness distribution and structural hierarchy of each plate, provide seahorses with joint flexibility while shielding them against impact and crushing. Mimicking seahorse armor may lead to novel bio-inspired technologies, such as flexible armor, fracture-resistant structures or prehensile robotics. PMID:23470547

  16. Preferred orientation in experimentally deformed stishovite: implications for deformation mechanisms

    NASA Astrophysics Data System (ADS)

    Kaercher, Pamela M.; Zepeda-Alarcon, Eloisa; Prakapenka, Vitali B.; Kanitpanyacharoen, Waruntorn; Smith, Jesse S.; Sinogeikin, Stanislav; Wenk, Hans-Rudolf

    2015-04-01

    Although the crystal structure of the high-pressure SiO2 polymorph stishovite has been studied in detail, little is known about the development of crystallographic preferred orientation (CPO) during deformation in stishovite. Insight into CPO and associated deformation mechanics of stishovite would provide important information for understanding subduction of quartz-bearing crustal rocks into the mantle. To study CPO development, we converted a natural sample of flint to stishovite in a laser-heated diamond anvil cell and compressed the stishovite aggregate up to 38 GPa. We collected diffraction patterns in radial geometry to examine in situ development of crystallographic preferred orientation and find that (001) poles preferentially align with the compression direction. Viscoplastic self-consistent modeling suggests the most likely slip systems at high pressure and ambient temperature are pyramidal and basal slip.

  17. Imaging active faulting in a region of distributed deformation from the joint clustering of focal mechanisms and hypocentres: Application to the Azores-western Mediterranean region

    NASA Astrophysics Data System (ADS)

    Custódio, Susana; Lima, Vânia; Vales, Dina; Cesca, Simone; Carrilho, Fernando

    2016-04-01

    The matching between linear trends of hypocentres and fault planes indicated by focal mechanisms (FMs) is frequently used to infer the location and geometry of active faults. This practice works well in regions of fast lithospheric deformation, where earthquake patterns are clear and major structures accommodate the bulk of deformation, but typically fails in regions of slow and distributed deformation. We present a new joint FM and hypocentre cluster algorithm that is able to detect systematically the consistency between hypocentre lineations and FMs, even in regions of distributed deformation. We apply the method to the Azores-western Mediterranean region, with particular emphasis on western Iberia. The analysis relies on a compilation of hypocentres and FMs taken from regional and global earthquake catalogues, academic theses and technical reports, complemented by new FMs for western Iberia. The joint clustering algorithm images both well-known and new seismo-tectonic features. The Azores triple junction is characterised by FMs with vertical pressure (P) axes, in good agreement with the divergent setting, and the Iberian domain is characterised by NW-SE oriented P axes, indicating a response of the lithosphere to the ongoing oblique convergence between Nubia and Eurasia. Several earthquakes remain unclustered in the western Mediterranean domain, which may indicate a response to local stresses. The major regions of consistent faulting that we identify are the mid-Atlantic ridge, the Terceira rift, the Trans-Alboran shear zone and the north coast of Algeria. In addition, other smaller earthquake clusters present a good match between epicentre lineations and FM fault planes. These clusters may signal single active faults or wide zones of distributed but consistent faulting. Mainland Portugal is dominated by strike-slip earthquakes with fault planes coincident with the predominant NNE-SSW and WNW-ESE oriented earthquake lineations. Clusters offshore SW Iberia are

  18. Deformation mechanism crossover and mechanical behaviour in nanocrystalline materials.

    SciTech Connect

    Yamakov, V.; Wolf, D.; Phillpot, S. R.; Mukherjee, A. K.; Gleiter, H.; Materials Science Division; Univ. of California-Davis; Forschungszentrum Karlsruhe

    2003-06-01

    We use molecular dynamics simulations to elucidate the transition with decreasing grain size from a dislocation- to a grain-boundary-based deformation mechanism in nanocrystalline fcc metals. Our simulations reveal that this crossover is accompanied by a pronounced transition in the mechanical behaviour of the material; namely, at the grain size where the crossover occurs (the 'strongest size'), the strain rate under tensile elongation goes through a minimum. This simultaneous transition in both the deformation mechanism and the corresponding mechanical behaviour offers an explanation for the experimentally observed crossover in the yield strength of nanocrystalline materials, from Hall-Petch hardening to 'inverse Hall-Petch' softening.

  19. Deformation Mechanisms of Gum Metals Under Nanoindentation

    NASA Astrophysics Data System (ADS)

    Sankaran, Rohini Priya

    Gum Metal is a set of multi-component beta-Ti alloys designed and developed by Toyota Central R&D Labs in 2003 to have a nearly zero shear modulus in the direction. After significant amounts of cold-work (>90%), these alloys were found to have yield strengths at a significant fraction of the predicted ideal strengths and exhibited very little work hardening. It has been speculated that this mechanical behavior may be realized through an ideal shear mechanism as opposed to conventional plastic deformation mechanisms, such as slip, and that such a mechanism may be realized through a defect structure termed "nanodisturbance". It is furthermore theorized that for near ideal strength to be attained, dislocations need to be pinned at sufficiently high stresses. It is the search for these defects and pinning points that motivates the present study. However, the mechanism of plastic deformation and the true origin of specific defect structures unique to gum metals is still controversial, mainly due to the complexity of the beta-Ti alloy system and the heavily distorted lattice exhibited in cold worked gum metals, rendering interpretation of images difficult. Accordingly, the first aim of this study is to clarify the starting as-received microstructures of gum metal alloys through conventional transmission electron microscopy (TEM) and aberration-corrected high resolution scanning transmission electron microscopy with high-angle annular dark field detector (HAADF-HRSTEM) imaging. To elucidate the effects of beta-stability and starting microstructure on the deformation behavior of gum metals and thus to provide adequate context for potentially novel deformation structures, we investigate three alloy conditions: gum metal that has undergone solution heat treatment (STGM), gum metal that has been heavily cold worked (CWGM), and a solution treated alloy of nominal gum metal composition, but leaner in beta-stabilizing content (ST Ref-1). In order to directly relate observed

  20. Deformation Monitoring of AN Active Fault

    NASA Astrophysics Data System (ADS)

    Ostapchuk, A.

    2015-12-01

    The discovery of low frequency earthquakes, slow slip events and other deformation phenomena, new for geophysics, change our understanding of how the energy accumulated in the Earth's crust do release. The new geophysical data make one revise the underlying mechanism of geomechanical processes taking place in fault zones. Conditions for generating different slip modes are still unclear. The most vital question is whether a certain slip mode is intrinsic for a fault or may be controlled by external factors. This work presents the results of two and a half year deformation monitoring of a discontinuity in the zone of the Main Sayanskiy Fault. Main Sayanskiy Fault is right-lateral strike-slip fault. Observations were performed in the tunnel of Talaya seismic station (TLY), Irkutsk region, Russia. Measurements were carried out 70 m away from the entrance of the tunnel, the thickness of overlying rock was about 30 m. Inductive sensors of displacement were mounted at the both sides of a discontinuity, which recorded three components of relative fault side displacement with the accuracy of 0.2 mcm. Temperature variation inside the tunnel didn't exceed 0.5oC during the all period of observations. Important information about deformation properties of an active fault was obtained. A pronounced seasonality of deformation characteristics of discontinuity is observed in the investigated segment of rock. A great number of slow slip events with durations from several hours to several weeks were registered. Besides that alterations of fault deformation characteristics before the megathrust earthquake M9.0 Tohoku Oki 11 March 2011 and reaction to the event itself were detected. The work was supported by the Russian Science Foundation (grant no. 14-17-00719).

  1. Deformation mechanisms of irradiated metallic nanofoams

    NASA Astrophysics Data System (ADS)

    Zepeda-Ruiz, L. A.; Martinez, E.; Caro, M.; Fu, E. G.; Caro, A.

    2013-07-01

    It was recently proposed that within a particular window in the parameter space of temperature, ion energy, dose rate, and filament diameter, nanoscale metallic foams could show radiation tolerance [Bringa et al., Nano Lett. 12, 3351 (2012)]. Outside this window, damage appears in the form of vacancy-related stacking fault tetrahedra (SFT), with no effects due to interstitials [Fu et al., Appl. Phys. Lett. 101, 191607 (2012)]. These SFT could be natural sources of dislocations within the ligaments composing the foam and determine their mechanical response. We employ molecular dynamics simulations of cylindrical ligaments containing an SFT to obtain an atomic-level picture of their deformation behavior under compression. We find that plastic deformation originates at the edges of the SFT, at lower stress than needed to create dislocations at the surface. Our results predict that nanoscale foams soften under irradiation, a prediction not yet tested experimentally.

  2. Deformation mechanisms of electrostrictive graft elastomer

    NASA Astrophysics Data System (ADS)

    Wang, Youqi; Sun, Changjie; Zhou, Eric; Su, Ji

    2004-12-01

    The electrostrictive graft elastomer is a new type of electroactive polymer. Recently developed by NASA, it consists of flexible backbone chains, each with side chains, called grafts. Neighboring backbone grafts physically cross-link and form crystal units. The flexible backbone chain and the crystal graft unit consist of polarized monomers, which contain atoms with electric partial charges, generating dipole moments. When the elastomer is placed into an electric field, external rotating moments are applied to the dipole moment. This stimulates electrostrictive strain in the graft elastomer. In this paper, the deformation of the elastomer under the action of an electric field is explained by means of two dominant mechanisms: crystal graft unit rotation and backbone chain reorientation. A two-dimensional computational model is established to analyze the deformation.

  3. Deformed Coherent State for Multiparticle Production Mechanism

    NASA Astrophysics Data System (ADS)

    Wang, W. Y.; Leong, Q.; Ng, W. K.; Dewanto, A.; Chan, A. H.; Oh, C. H.

    2014-04-01

    The deformation structure function describing the Generalised Multiplicities Distribution (GMD), Negative Binomial Distribution (NBD), Furry-Yule Distribution (FYD), and their corresponding deformed coherent states and second order correlation function g(2) are derived. A superposition model of the GMD and NBD states is then proposed as a general description of the mechanism that gives rise to the double NBD model first proposed by Giovannini. The model is applied to LHC multiplicity data at |η| ≤ 2.4 and 0.9, 2.36 and 7 TeV, from the CMS collaboration at CERN, and the second order correlation g(2) of the model is then compared with the normalised second factorial moment {F_2}/F_1^2 of the multiplicity.

  4. Universal mechanism of thermo-mechanical deformation in metallic glasses

    SciTech Connect

    Dmowski, W.; Tong, Y.; Iwashita, T.; Egami, Takeshi; Yokoyama, Y.

    2015-02-11

    Here we investigated the atomistic structure of metallic glasses subjected to thermo-mechanical creep deformation using high energy x-ray diffraction and molecular dynamics simulation. The experiments were performed in-situ, at high temperatures as a time dependent deformation in the elastic regime, and ex-situ on samples quenched under stress. We show that all the anisotropic structure functions of the samples undergone thermo-mechanical creep can be scaled into a single curve, regardless of the magnitude of anelastic strain, stress level and the sign of the stress, demonstrating universal behavior and pointing to unique atomistic unit of anelastic deformation. The structural changes due to creep are strongly localized within the second nearest neighbors, involving only a small group of atoms.

  5. Universal mechanism of thermo-mechanical deformation in metallic glasses

    DOE PAGESBeta

    Dmowski, W.; Tong, Y.; Iwashita, T.; Egami, Takeshi; Yokoyama, Y.

    2015-02-11

    Here we investigated the atomistic structure of metallic glasses subjected to thermo-mechanical creep deformation using high energy x-ray diffraction and molecular dynamics simulation. The experiments were performed in-situ, at high temperatures as a time dependent deformation in the elastic regime, and ex-situ on samples quenched under stress. We show that all the anisotropic structure functions of the samples undergone thermo-mechanical creep can be scaled into a single curve, regardless of the magnitude of anelastic strain, stress level and the sign of the stress, demonstrating universal behavior and pointing to unique atomistic unit of anelastic deformation. The structural changes due tomore » creep are strongly localized within the second nearest neighbors, involving only a small group of atoms.« less

  6. Deformation Mechanisms of Gum Metals Under Nanoindentation

    NASA Astrophysics Data System (ADS)

    Sankaran, Rohini Priya

    Gum Metal is a set of multi-component beta-Ti alloys designed and developed by Toyota Central R&D Labs in 2003 to have a nearly zero shear modulus in the direction. After significant amounts of cold-work (>90%), these alloys were found to have yield strengths at a significant fraction of the predicted ideal strengths and exhibited very little work hardening. It has been speculated that this mechanical behavior may be realized through an ideal shear mechanism as opposed to conventional plastic deformation mechanisms, such as slip, and that such a mechanism may be realized through a defect structure termed "nanodisturbance". It is furthermore theorized that for near ideal strength to be attained, dislocations need to be pinned at sufficiently high stresses. It is the search for these defects and pinning points that motivates the present study. However, the mechanism of plastic deformation and the true origin of specific defect structures unique to gum metals is still controversial, mainly due to the complexity of the beta-Ti alloy system and the heavily distorted lattice exhibited in cold worked gum metals, rendering interpretation of images difficult. Accordingly, the first aim of this study is to clarify the starting as-received microstructures of gum metal alloys through conventional transmission electron microscopy (TEM) and aberration-corrected high resolution scanning transmission electron microscopy with high-angle annular dark field detector (HAADF-HRSTEM) imaging. To elucidate the effects of beta-stability and starting microstructure on the deformation behavior of gum metals and thus to provide adequate context for potentially novel deformation structures, we investigate three alloy conditions: gum metal that has undergone solution heat treatment (STGM), gum metal that has been heavily cold worked (CWGM), and a solution treated alloy of nominal gum metal composition, but leaner in beta-stabilizing content (ST Ref-1). In order to directly relate observed

  7. Ruthenium Aluminides: Deformation Mechanisms and Substructure Development

    SciTech Connect

    Tresa M. Pollock

    2005-05-11

    Structural and functional materials that can operate in severe, high temperature environments are key to the operation of a wide range of energy generation systems. Because continued improvements in the energy efficiency of these systems is critical, the need for new materials with higher temperature capabilities is inevitable. Intermetallic compounds, with strong bonding and generally high melting points offer this possibility for a broad array of components such as coatings, electrode materials, actuators and/or structural elements. RuAl is a very unusual intermetallic compound among the large number of B2compounds that have been identified and investigated to date. This material has a very high melting temperature of 2050?C, low thermal expansion, high thermal conductivity and good corrosion resistance. Unlike most other high temperature B2 intermetallics, RuAl possesses good intrinsic deformability at low temperatures. In this program fundamental aspects of low and high temperature mechanical properties and deformation mechanisms in binary and higher order RuAl-based systems have been investigated. Alloying additions of interest included platinum, boron and niobium. Additionally, preliminary studies on high temperature oxidation behavior of these materials have been conducted.

  8. A mechanism for tectonic deformation on Venus

    NASA Technical Reports Server (NTRS)

    Phillips, Roger J.

    1986-01-01

    In the absence of identifiable physiographic features directly associated with plate tectonics, alternate mechanisms are sought for the intense tectonic deformation observed in radar images of Venus. One possible mechanism is direct coupling into an elastic lithosphere of the stresses associated with convective flow in the interior. Spectral Green's function solutions have been obtained for stresses in an elastic lithosphere overlying a Newtonian interior with an exponential depth dependence of viscosity, and a specified surface-density distribution driving the flow. At long wavelengths and for a rigid elastic/fluid boundary condition, horizontal normal stresses in the elastic lid are controlled by the vertical shear stress gradient and are directly proportional to the depth of the density disturbance in the underlying fluid. The depth and strength of density anomalies in the Venusian interior inferred by analyses of long wavelength gravity data suggest that stresses in excess of 100 MPa would be generated in a 10 km thick elastic lid unless a low viscosity channel occurring beneath the lid or a positive viscosity gradient uncouples the flow stresses. The great apparent depth of compensation of topographic features argues against this, however, thus supporting the importance of the coupling mechanism. If there is no elastic lid, stresses will also be very high near the surface, providing also that the viscosity gradient is negative.

  9. Monocytic Cells Become Less Compressible but More Deformable upon Activation

    PubMed Central

    Ravetto, Agnese; Wyss, Hans M.; Anderson, Patrick D.; den Toonder, Jaap M. J.; Bouten, Carlijn V. C.

    2014-01-01

    Aims Monocytes play a significant role in the development of atherosclerosis. During the process of inflammation, circulating monocytes become activated in the blood stream. The consequent interactions of the activated monocytes with the blood flow and endothelial cells result in reorganization of cytoskeletal proteins, in particular of the microfilament structure, and concomitant changes in cell shape and mechanical behavior. Here we investigate the full elastic behavior of activated monocytes in relation to their cytoskeletal structure to obtain a better understanding of cell behavior during the progression of inflammatory diseases such as atherosclerosis. Methods and Results The recently developed Capillary Micromechanics technique, based on exposing a cell to a pressure difference in a tapered glass microcapillary, was used to measure the deformation of activated and non-activated monocytic cells. Monitoring the elastic response of individual cells up to large deformations allowed us to obtain both the compressive and the shear modulus of a cell from a single experiment. Activation by inflammatory chemokines affected the cytoskeletal organization and increased the elastic compressive modulus of monocytes with 73–340%, while their resistance to shape deformation decreased, as indicated by a 25–88% drop in the cell’s shear modulus. This decrease in deformability is particularly pronounced at high strains, such as those that occur during diapedesis through the vascular wall. Conclusion Overall, monocytic cells become less compressible but more deformable upon activation. This change in mechanical response under different modes of deformation could be important in understanding the interplay between the mechanics and function of these cells. In addition, our data are of direct relevance for computational modeling and analysis of the distinct monocytic behavior in the circulation and the extravascular space. Lastly, an understanding of the changes of monocyte

  10. Constitutive Law and Flow Mechanism in Diamond Deformation

    DOE PAGESBeta

    Yu, Xiaohui; Raterron, Paul; Zhang, Jianzhong; Lin, Zhijun; Wang, Liping; Zhao, Yusheng

    2012-11-19

    Constitutive laws and crystal plasticity in diamond deformation have been the subjects of substantial interest since synthetic diamond was made in 1950's. To date, however, little is known quantitatively regarding its brittle-ductile properties and yield strength at high temperatures. In this paper, we report, for the first time, the strain-stress constitutive relations and experimental demonstration of deformation mechanisms under confined high pressure. The deformation at room temperature is essentially brittle, cataclastic, and mostly accommodated by fracturing on {111} plane with no plastic yielding at uniaxial strains up to 15%. At elevated temperatures of 1000°C and 1200°C diamond crystals exhibit significantmore » ductile flow with corresponding yield strength of 7.9 and 6.3 GPa, indicating that diamond starts to weaken when temperature is over 1000°C. Finally, at high temperature the plastic deformation and ductile flow is meditated by the <110>{111} dislocation glide and a very active {111} micro-twinning.« less

  11. Constitutive Law and Flow Mechanism in Diamond Deformation

    SciTech Connect

    Yu, Xiaohui; Raterron, Paul; Zhang, Jianzhong; Lin, Zhijun; Wang, Liping; Zhao, Yusheng

    2012-11-19

    Constitutive laws and crystal plasticity in diamond deformation have been the subjects of substantial interest since synthetic diamond was made in 1950's. To date, however, little is known quantitatively regarding its brittle-ductile properties and yield strength at high temperatures. In this paper, we report, for the first time, the strain-stress constitutive relations and experimental demonstration of deformation mechanisms under confined high pressure. The deformation at room temperature is essentially brittle, cataclastic, and mostly accommodated by fracturing on {111} plane with no plastic yielding at uniaxial strains up to 15%. At elevated temperatures of 1000°C and 1200°C diamond crystals exhibit significant ductile flow with corresponding yield strength of 7.9 and 6.3 GPa, indicating that diamond starts to weaken when temperature is over 1000°C. Finally, at high temperature the plastic deformation and ductile flow is meditated by the <110>{111} dislocation glide and a very active {111} micro-twinning.

  12. Constitutive Law and Flow Mechanism in Diamond Deformation

    PubMed Central

    Yu, Xiaohui; Raterron, Paul; Zhang, Jianzhong; Lin, Zhijun; Wang, Liping; Zhao, Yusheng

    2012-01-01

    Constitutive laws and crystal plasticity in diamond deformation have been the subjects of substantial interest since synthetic diamond was made in 1950's. To date, however, little is known quantitatively regarding its brittle-ductile properties and yield strength at high temperatures. Here we report, for the first time, the strain-stress constitutive relations and experimental demonstration of deformation mechanisms under confined high pressure. The deformation at room temperature is essentially brittle, cataclastic, and mostly accommodated by fracturing on {111} plane with no plastic yielding at uniaxial strains up to 15%. At elevated temperatures of 1000°C and 1200°C diamond crystals exhibit significant ductile flow with corresponding yield strength of 7.9 and 6.3 GPa, indicating that diamond starts to weaken when temperature is over 1000°C. At high temperature the plastic deformation and ductile flow is meditated by the <110>{111} dislocation glide and a very active {111} micro-twinning. PMID:23166859

  13. Plate-tectonic mechanism of Laramide deformation.

    USGS Publications Warehouse

    Hamilton, W.

    1981-01-01

    The Laramide compressive deformation of the craton was caused by a clockwise rotation of about 2-4o of the Colorado Plateau region relative to the continental interior, during late Late Cretaceous and early Tertiary time. Late Paleozoic and Neogene deformation of the craton also were produced by motion of a southwestern subplate relative to the continental interior. -from Author

  14. Production, structure, texture, and mechanical properties of severely deformed magnesium

    NASA Astrophysics Data System (ADS)

    Volkov, A. Yu.; Antonova, O. V.; Kamenetskii, B. I.; Klyukin, I. V.; Komkova, D. A.; Antonov, B. D.

    2016-05-01

    Methods of the severe plastic deformation (SPD) of pure magnesium at room temperature, namely, transverse extrusion and hydroextrusion in a self-destroyed shell, have been developed. The maximum true strain of the samples after the hydroextrusion was e ~ 3.2; in the course of transverse extrusion and subsequent cold rolling, a true strain of e ~ 6.0 was achieved. The structure and mechanical properties of the magnesium samples have been studied in different structural states. It has been shown that the SPD led to a decrease in the grain size d to ~2 μm; the relative elongation at fracture δ increased to ~20%. No active twinning has been revealed. The reasons for the high plasticity of magnesium after SPD according to the deformation modes suggested are discussed from the viewpoint of the hierarchy of the observed structural states.

  15. Structural anisotropy in metallic glasses induced by mechanical deformation

    SciTech Connect

    Dmowski, W.; Egami, T.

    2009-03-06

    We observed structural anisotropy in metallic glasses samples deformed by homogenous mechanical creep and by inhomogeneous compression using high energy X-ray diffraction. Pair distribution function analysis indicates bond anisotropy in the first atomic shell. This suggests that mechanical deformation involves rearrangements in a cluster of atoms by a bond reformation.

  16. Deformation mechanisms of antigorite serpentinite at subduction zone conditions determined from experimentally and naturally deformed rocks

    NASA Astrophysics Data System (ADS)

    Auzende, Anne-Line; Escartin, Javier; Walte, Nicolas P.; Guillot, Stéphane; Hirth, Greg; Frost, Daniel J.

    2015-02-01

    We performed deformation-DIA experiments on antigorite serpentinite at pressures of 1-3.5 GPa and temperatures of between 400 and 650 °C, bracketing the stability of antigorite under subduction zone conditions. For each set of pressure-temperature (P-T) conditions, we conducted two runs at strain rates of 5 ×10-5 and 1 ×10-4 s-1. We complemented our study with a sample deformed in a Griggs-type apparatus at 1 GPa and 400 °C (Chernak and Hirth, 2010), and with natural samples from Cuba and the Alps deformed under blueschist/eclogitic conditions. Optical and transmission electron microscopies were used for microstructural characterization and determination of deformation mechanisms. Our observations on experimentally deformed antigorite prior to breakdown show that deformation is dominated by cataclastic flow with observable but minor contribution of plastic deformation (microkinking and (001) gliding mainly expressed by stacking disorder mainly). In contrast, in naturally deformed samples, plastic deformation structures are dominant (stacking disorder, kinking, pressure solution), with minor but also perceptible contribution of brittle deformation. When dehydration occurs in experiments, plasticity increases and is coupled to local embrittlement that we attribute to antigorite dehydration. In dehydrating samples collected in the Alps, embrittlement is also observed suggesting that dehydration may contribute to intermediate-depth seismicity. Our results thus show that semibrittle deformation operates within and above the stability field of antigorite. However, the plastic deformation recorded by naturally deformed samples was likely acquired at low strain rates. We also document that the corrugated structure of antigorite controls the strain accommodation mechanisms under subduction conditions, with preferred inter- and intra-grain cracking along (001) and gliding along both a and b. We also show that antigorite rheology in subduction zones is partly controlled

  17. Deformation Mechanisms of Antigorite Serpentinite at Subduction Zone Conditions Determined from Experimentally and Naturally Deformed Rocks

    NASA Astrophysics Data System (ADS)

    Auzende, A. L.; Escartin, J.; Walte, N.; Guillot, S.; Hirth, G.; Frost, D. J.

    2014-12-01

    The rheology of serpentinite, and particularly that of antigorite-bearing rocks, is of prime importance for understanding subduction zone proceses, including decoupling between the downwelling slab and the overriding plate, exhumation of high-pressure rocks, fluids pathways and, more generally, mantle wedge dynamics. We present results from deformation-DIA experiments on antigorite serpentinite performed under conditions relevant of subduction zones (1-3.5 GPa ; 400-650°C). We complemented our study with a sample deformed in a Griggs-type apparatus at 1 GPa and 400°C (Chernak and Hirth, EPSL, 2010), and with natural samples from Cuba and the Alps deformed under blueschist/eclogitic conditions. Our observations on experimental samples of antigorite deformed within its stability field show that deformation is dominated by cataclastic flow; we can only document a minor contribution of plastic deformation. In naturally deformed samples, deformation-related plastic structures largely dominate strain accommodation, but we also document a minor contribution of brittle deformation. When dehydration occurs in experiments, plasticity increases, and is coupled to local embrittlement attributed to hydraulic fracturating due to the migration of dehydration fluids. Our results thus show that semibrittle deformation operates within and above the stability field of antigorite. We also document that the corrugated structure of antigorite has a control on the strain accommodation mechanisms under subduction conditions, with preferred inter and intra-cracking along (001) and gliding along both a and b. Deformation dominated by brittle processes, as observed in experiments, may occur during deformation at elevated (seismic?) strain rates, while plastic deformation, as observed in naturally deformed rocks, may correspond instead to low strain rates instead (aseismic creep?). We also discuss the role of antigorite rheology and mode of deformation on fluid transport.

  18. Significance of grain sliding mechanisms for ductile deformation of rocks

    NASA Astrophysics Data System (ADS)

    Dimanov, A.; Bourcier, M.; Gaye, A.; Héripré, E.; Bornert, M.; Raphanel, J.; Ludwig, W.

    2013-12-01

    Ductile shear zones at depth present polyphase and heterogeneous rocks and multi-scale strain localization patterns. Most strain concentrates in ultramylonitic layers, which exhibit microstructural signatures of several concomitant deformation mechanisms. The latter are either active in volume (dislocation creep), or in the vicinity and along interfaces (grain sliding and solution mass transfer). Because their chronology of appearance and interactions are unclear, inference of the overall rheology seems illusory. We have therefore characterized over a decade the rheology of synthetic lower crustal materials with different compositions and fluid contents, and for various microstructures. Non-Newtonian flow clearly related to dominant dislocation creep. Conversely, Newtonian behavior involved grain sliding mechanisms, but crystal plasticity could be identified as well. In order to clarify the respective roles of these mechanisms we underwent a multi-scale investigation of the ductile deformation of rock analog synthetic halite with controlled microstructures. The mechanical tests were combined with in-situ optical microscopy, scanning electron microscopy and X ray computed tomography, allowing for digital image correlation (DIC) techniques and retrieval of full strain field. Crystal plasticity dominated, as evidenced by physical slip lines and DIC computed slip bands. Crystal orientation mapping allowed to identify strongly active easy glide {110} <110> systems. But, all other slip systems were observed as well, and especially near interfaces, where their activity is necessary to accommodate for the plastic strain incompatibilities between neighboring grains. We also evidenced grain boundary sliding (GBS), which clearly occurred as a secondary, but necessary, accommodation mechanism. The DIC technique allowed the quantification of the relative contribution of each mechanism. The amount of GBS clearly increased with decreasing grain size. Finite element (FE) modeling

  19. Inelastic deformation mechanisms in a transverse MMC lamina under compression

    NASA Technical Reports Server (NTRS)

    Newaz, Golam M.; Majumdar, Bhaskar S.

    1992-01-01

    An investigation was undertaken to study the inelastic deformation mechanisms in (90)(sub 8) Ti 15-3/SCS-6 lamina subjected to pure compression. Both mechanical behavior and microstructural evaluation were undertaken at room temperature, 538 and 650 C. Results indicate that mechanical response and deformation characteristics are significantly different in monotonic tension and compression. The inelastic deformation mechanisms in compression are controlled by radial fiber fracture, matrix plasticity and fiber-matrix debonding. The radial fiber fracture is a new damage mode observed for metal-matrix composites (MMC).

  20. Reciprocating motion of active deformable particles

    NASA Astrophysics Data System (ADS)

    Tarama, M.; Ohta, T.

    2016-05-01

    Reciprocating motion of an active deformable particle in a homogeneous medium is studied theoretically. For generality, we employ a simple model derived from symmetry considerations for the center-of-mass velocity and elliptical and triangular deformations in two dimensions. We carry out, for the first time, a systematic investigation of the reciprocating motion of a self-propelled particle. It is clarified that spontaneous breaking of the front-rear asymmetry is essential for the reciprocating motion. Moreover, two routes are found for the formation of the reciprocating motion. One is a bifurcation from a motionless stationary state. The other is destabilisation of an oscillatory rectilinear motion.

  1. Fatigue Behavior and Deformation Mechanisms in Inconel 718 Superalloy Investigated

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The nickel-base superalloy Inconel 718 (IN 718) is used as a structural material for a variety of components in the space shuttle main engine (SSME) and accounts for more than half of the total weight of this engine. IN 718 is the bill-of-material for the pressure vessels of nickel-hydrogen batteries for the space station. In the case of the space shuttle main engine, structural components are typically subjected to startup and shutdown load transients and occasional overloads in addition to high-frequency vibratory loads from routine operation. The nickel-hydrogen battery cells are prooftested before service and are subjected to fluctuating pressure loads during operation. In both of these applications, the structural material is subjected to a monotonic load initially, which is subsequently followed by fatigue. To assess the life of these structural components, it is necessary to determine the influence of a prior monotonic load on the subsequent fatigue life of the superalloy. An insight into the underlying deformation and damage mechanisms is also required to properly account for the interaction between the prior monotonic load and the subsequent fatigue loading. An experimental investigation was conducted to establish the effect of prior monotonic straining on the subsequent fatigue behavior of wrought, double-aged, IN 718 at room temperature. First, monotonic strain tests and fully-reversed, strain-controlled fatigue tests were conducted on uniform-gage-section IN 718 specimens. Next, fully reversed fatigue tests were conducted under strain control on specimens that were monotonically strained in tension. Results from this investigation indicated that prior monotonic straining reduced the fatigue resistance of the superalloy particularly at the lowest strain range. Some of the tested specimens were sectioned and examined by transmission electron microscopy to reveal typical microstructures as well as the active deformation and damage mechanisms under each of

  2. Creep deformation mechanisms in modified 9Cr-1Mo steel

    NASA Astrophysics Data System (ADS)

    Shrestha, Triratna; Basirat, Mehdi; Charit, Indrajit; Potirniche, Gabriel P.; Rink, Karl K.; Sahaym, Uttara

    2012-04-01

    Modified 9Cr-1Mo (Grade 91) steel is currently considered as a candidate material for reactor pressure vessels (RPVs) and reactor internals for the Very High Temperature Reactor (VHTR). The tensile creep behavior of modified 9Cr-1Mo steel (Grade 91) was studied in the temperature range of 873-1023 K and stresses between 35 MPa and 350 MPa. Analysis of creep results yielded stress exponents of ∼9-11 in the higher stress regime and ∼1 in the lower stress regime. The high stress exponent in the power-law creep regime was rationalized by invoking the concept of threshold stress, which represents the lattice diffusion controlled dislocation climb process. Without threshold stress compensation, the activation energy was 510 ± 51 kJ/mol, while after correcting for the threshold stress, the activation energy decreased to 225 ± 24 kJ/mol. This value is close to the activation energy for lattice self-diffusion in α-Fe. Threshold stress calculations were performed for the high stress regime at all test temperatures. The calculated threshold stress showed a strong dependence on temperature. The creep behavior of Grade 91 steel was described by the modified Bird-Mukherjee-Dorn relation. The rate controlling creep deformation mechanism in the high stress regime was identified as the edge dislocation climb with a stress exponent of n = 5. On the other hand, the deformation mechanism in the Newtonian viscous creep regime (n = 1) was identified as the Nabarro-Herring creep.

  3. Mechanisms of crustal deformation in the western US

    NASA Technical Reports Server (NTRS)

    Turcotte, Donald L.

    1986-01-01

    The deformation processes in the western United States were studied, considering both deterministic models and random or statistical models. The role of the intracrustal delamination and mechanisms of crustal thinning were also examined. The application of fractal techniques to understand how the crust is deforming was studied in complex regions. Work continued on the development of a fractal based model for deformation in the western United States. Fractal studies were also extended to the study of topography and the geoid.

  4. Defect structure and deformation mechanisms in naturally deformed augite and enstatite

    NASA Astrophysics Data System (ADS)

    Skrotzki, W.

    1994-01-01

    The defect structure of naturally deformed augite containing enstatite lamellae has been investigated by conventional and high resolution transmission electron microscopy in order to obtain information on the deformation mechanisms of these important rock-forming minerals. The aggregate under investigation originates from a coarse-grained websterite dyke of the Balmuccia Massif which is located within the Ivrea Zone (NW-Italy). Dyke formation may have taken place during intrusion of the peridotite massif into the lower crust at temperatures of about 1000°C. Deformation of the pyroxenite dykes may be due to subsequent tilting of the Ivrea Zone at lower temperatures (about 650°C). Cooling of the augites led to exsolution of orthopyroxene, clinoamphibole and two generations of pigeonite lamellae. The microstructure observed in the augite matrix and the enstatite exsolution lamellae consists of dislocations, planar faults and subgrain boundaries. Burgers vectors and dislocation line directions in augite indicate the activation of the (100)[001], {110} {1}/{2}<110>, {110} {1}/{2}1/2<112>, (100)[010], (010)[100], (010)<101> and {110}<111> slip systems, the first two being the most active. Dislocation reactions are common, as well as heterogeneous precipitation of pigeonite at [001] dislocations. The subgrain boundaries observed are { hkO} tilt boundaries with [001] tilt axis and (010) twist boundaries. Occasionally (100) twin lamellae exist. The dislocations in the deformed enstatite lamellae have [001], [010] and [100]Burgers vectors, as well as combinations of these. In general, all dislocations are dissociated. The subgrain boundaries observed are { hkO} tilt boundaries with [001] tilt axis. The planar faults produced by dissociation of [001], [010] and <111> dislocations in augite are stacking faults (SFs) on (100), (010) and {110}, respectively, that of {1}/{2}<112> and <101> dislocations are chain multiplicity faults (CMFs) on (010). The planar faults produced in

  5. Deformation and failure mechanisms in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Newaz, G.; Majumdar, B. S.

    1991-01-01

    An investigation was undertaken to determine the key deformation mechanisms and their interaction leading to failure of both 0 degree and 90 degree Ti 15-3/SCS-6 laminae under monotonic loading. The experimental results suggest that inelastic deformation in the 0-degree lamina is dominated by plastic deformation and that in the 90-degree lamina is dominated by both fiber-matrix debonding and plasticity. The loading-unloading response, monitoring of Poisson's ratio and microscopy were utilized to identify the key deformation mechanisms. The sequence of deformation mechanisms leading to failure are identified for both the 0 and the 90-degree specimens. The threshold strains for plasticity or damage which are referred to as 'microdeformation' in the 0 deg and 90 deg laminae are approximately 0.004 and 0.002, respectively, at room temperature. These strain levels may be considered critical in initiation based structural design with these composites.

  6. Multiscale Graphene Topographies Programmed by Sequential Mechanical Deformation.

    PubMed

    Chen, Po-Yen; Sodhi, Jaskiranjeet; Qiu, Yang; Valentin, Thomas M; Steinberg, Ruben Spitz; Wang, Zhongying; Hurt, Robert H; Wong, Ian Y

    2016-05-01

    Multigenerational graphene oxide architectures can be programmed by specific sequences of mechanical deformations. Each new deformation results in a progressively larger set of features decorated by smaller preexisting patterns, indicating a structural "memory." It is shown that these multiscale architectures are superhydrophobic and display excellent functionality as electrochemical electrodes. PMID:26996525

  7. The mechanical deformation mechanisms in knitted fabric composites

    SciTech Connect

    Kelay, M.S.; Bader, D.L.; Reed, P.E.

    1994-12-31

    Knitted fabric composites have certain advantages over woven composites, particularly in their ability to conform to complicated contours. As a consequence, they demonstrate inferior mechanical characteristics compared to woven materials as a direct result of the presence of bent fibers. Such a knitted fabric composite made from, for example, glass fibers in a polyurethane matrix, can be used as an orthopaedic splinting bandage for immobilizing fractures of the upper and lower limbs. Relatively little research has been reported on knitted fabric composites was initiated. It was observed that knit patterns, type of fiber, size of fibers used, size of loops, coatings and lay-up procedure were all variables that could affect the structure/property relationship of knitted fabric composites. Tensile testing with optical measurement of strain was performed on knitted substrate and coated bandages in both course and wale directions. Results indicated that the knitted fabrics function as link mechanisms at the microscopic level, with knitted loops straightening and bending before the individual elements of the knitted yarn take up significant load and material deformation. Theoretical modeling of the glass knit structure, in both course and wale directions, agrees well with experimental testing.

  8. Strain gage network distinguishes between thermal and mechanical deformations

    NASA Technical Reports Server (NTRS)

    Cepollina, F. J.

    1966-01-01

    Strain gage network measures the thermal coefficient of linear expansion of composite metal structures. The network consists of a test gage and two dummy gages arranged to distinguish thermally induced deformation from mechanical strain.

  9. Deformation mechanisms in nanoscale single crystalline electroplated copper pillars

    NASA Astrophysics Data System (ADS)

    Jennings, Andrew T.

    Scientific research in nanotechnology has enabled advances in a diverse range of applications, such as: electronics, chemical sensing, and cancer treatment. In order to transition these nanotechnology-driven innovations out of the laboratory and into real-world applications, the resilience and mechanical reliability of nanoscale structures must be well understood in order to preserve functionality under real-world operating environments. Understanding the mechanical properties of nanoscale materials is especially important because several authors have shown that single crystalline metal pillars produced through focused-ion-beam milling have unique properties when the pillar diameter, D, approaches nanotechnology-relevant dimensions. The strength, sigma, of these pillars is size-dependent and is well described through a power-law relation showing that smaller is stronger: sigma∝D-n , where n is the exponent and is found to be 0.5≤n≤1.0 in face-centered-cubic metals. In this work, the fundamental deformation mechanisms governing the size-dependent mechanical properties are investigated through uniaxial compression and tension tests of electroplated single crystalline copper pillars with diameters between 75 nm and 1000 nm. At larger pillar diameters, D >125 nm, these copper pillars are shown to obey a similar size-dependent regime, demonstrating that the "smaller is stronger" phenomenon is a function of the pillar microstructure, as opposed to the fabrication route. Furthermore, the dominant dislocation mechanism in this size-dependent regime is shown to be the result of single-arm, or spiral, sources. At smaller pillar diameters, D≤125 nm, a strain-rate-dependent mechanism transition is observed through both the size-strength relation and also quantitative, experimental measures of the activation volume. This new deformation regime is characterized by a size-independent strength and is governed by surface dislocation nucleation, a thermally activated

  10. Deformation twinning mechanisms in FCC and HCP metals

    SciTech Connect

    Wang, Jian; Tome, Carlos N; Beyerlein, Irene J; Misra, Amit; Mara, N

    2011-01-31

    We report the recent work on twinning and detwinning in fcc and hcp metals based on the in situ and ex situ TEM observations and molecular dynamics simulations. Three aspects are discussed in this paper. (1) Detwinning in single-phase Cu with respect to growth twins, (2) deformation twinning in Ag-Cu composites, and (3) deformation twinning mechanisms in hcp metals. The main conclusion is that atomic structures of interfaces (twin boundaries, two-phases interface, and grain boundaries) play a crucial role in nucleating and propagating of deformation twins.

  11. Techniques for in situ HVEM mechanical deformation of nanostructural materials

    SciTech Connect

    Wall, M.A.; Barbee, T.W. Jr.; Dahmen, U.

    1995-08-07

    We have developed two in-situ HVEM techniques which allow us to begin fundamental investigations into the mechanisms of deformation and fracture in nonstructured materials. A procedure for the observation of tensile deformation and failure in multilayers materials in cross-section is given and also the development of an in-situ HVEM nanoindentor of surfaces and films on surfaces in cross-section.

  12. Active Beam Shaping System and Method Using Sequential Deformable Mirrors

    NASA Technical Reports Server (NTRS)

    Norman, Colin A. (Inventor); Pueyo, Laurent A. (Inventor)

    2015-01-01

    An active optical beam shaping system includes a first deformable mirror arranged to at least partially intercept an entrance beam of light and to provide a first reflected beam of light, a second deformable mirror arranged to at least partially intercept the first reflected beam of light from the first deformable mirror and to provide a second reflected beam of light, and a signal processing and control system configured to communicate with the first and second deformable mirrors. The first deformable mirror, the second deformable mirror and the signal processing and control system together provide a large amplitude light modulation range to provide an actively shaped optical beam.

  13. Fluctuating Nonlinear Spring Model of Mechanical Deformation of Biological Particles.

    PubMed

    Kononova, Olga; Snijder, Joost; Kholodov, Yaroslav; Marx, Kenneth A; Wuite, Gijs J L; Roos, Wouter H; Barsegov, Valeri

    2016-01-01

    The mechanical properties of virus capsids correlate with local conformational dynamics in the capsid structure. They also reflect the required stability needed to withstand high internal pressures generated upon genome loading and contribute to the success of important events in viral infectivity, such as capsid maturation, genome uncoating and receptor binding. The mechanical properties of biological nanoparticles are often determined from monitoring their dynamic deformations in Atomic Force Microscopy nanoindentation experiments; but a comprehensive theory describing the full range of observed deformation behaviors has not previously been described. We present a new theory for modeling dynamic deformations of biological nanoparticles, which considers the non-linear Hertzian deformation, resulting from an indenter-particle physical contact, and the bending of curved elements (beams) modeling the particle structure. The beams' deformation beyond the critical point triggers a dynamic transition of the particle to the collapsed state. This extreme event is accompanied by a catastrophic force drop as observed in the experimental or simulated force (F)-deformation (X) spectra. The theory interprets fine features of the spectra, including the nonlinear components of the FX-curves, in terms of the Young's moduli for Hertzian and bending deformations, and the structural damage dependent beams' survival probability, in terms of the maximum strength and the cooperativity parameter. The theory is exemplified by successfully describing the deformation dynamics of natural nanoparticles through comparing theoretical curves with experimental force-deformation spectra for several virus particles. This approach provides a comprehensive description of the dynamic structural transitions in biological and artificial nanoparticles, which is essential for their optimal use in nanotechnology and nanomedicine applications. PMID:26821264

  14. Fluctuating Nonlinear Spring Model of Mechanical Deformation of Biological Particles

    PubMed Central

    Kononova, Olga; Snijder, Joost; Kholodov, Yaroslav; Marx, Kenneth A.; Wuite, Gijs J. L.; Roos, Wouter H.; Barsegov, Valeri

    2016-01-01

    The mechanical properties of virus capsids correlate with local conformational dynamics in the capsid structure. They also reflect the required stability needed to withstand high internal pressures generated upon genome loading and contribute to the success of important events in viral infectivity, such as capsid maturation, genome uncoating and receptor binding. The mechanical properties of biological nanoparticles are often determined from monitoring their dynamic deformations in Atomic Force Microscopy nanoindentation experiments; but a comprehensive theory describing the full range of observed deformation behaviors has not previously been described. We present a new theory for modeling dynamic deformations of biological nanoparticles, which considers the non-linear Hertzian deformation, resulting from an indenter-particle physical contact, and the bending of curved elements (beams) modeling the particle structure. The beams’ deformation beyond the critical point triggers a dynamic transition of the particle to the collapsed state. This extreme event is accompanied by a catastrophic force drop as observed in the experimental or simulated force (F)-deformation (X) spectra. The theory interprets fine features of the spectra, including the nonlinear components of the FX-curves, in terms of the Young’s moduli for Hertzian and bending deformations, and the structural damage dependent beams’ survival probability, in terms of the maximum strength and the cooperativity parameter. The theory is exemplified by successfully describing the deformation dynamics of natural nanoparticles through comparing theoretical curves with experimental force-deformation spectra for several virus particles. This approach provides a comprehensive description of the dynamic structural transitions in biological and artificial nanoparticles, which is essential for their optimal use in nanotechnology and nanomedicine applications. PMID:26821264

  15. Investigating Deformation and Failure Mechanisms in Nanoscale Multilayer Metallic Composites

    SciTech Connect

    Zbib, Hussein M; Bahr, David F

    2014-10-22

    Over the history of materials science there are many examples of materials discoveries that have made superlative materials; the strongest, lightest, or toughest material is almost always a goal when we invent new materials. However, often these have been a result of enormous trial and error approaches. A new methodology, one in which researchers design, from the atoms up, new ultra-strong materials for use in energy applications, is taking hold within the science and engineering community. This project focused on one particular new classification of materials; nanolaminate metallic composites. These materials, where two metallic materials are intimately bonded and layered over and over to form sheets or coatings, have been shown over the past decade to reach strengths over 10 times that of their constituents. However, they are not yet widely used in part because while extremely strong (they don’t permanently bend), they are also not particularly tough (they break relatively easily when notched). Our program took a coupled approach to investigating new materials systems within the laminate field. We used computational materials science to explore ways to institute new deformation mechanisms that occurred when a tri-layer, rather than the more common bi-layer system was created. Our predictions suggested that copper-nickel or copper-niobium composites (two very common bi-layer systems) with layer thicknesses on the order of 20 nm and then layered 100’s of times, would be less tough than a copper-nickel-niobium metallic composite of similar thicknesses. In particular, a particular mode of permanent deformation, cross-slip, could be activated only in the tri-layer system; the crystal structure of the other bi-layers would prohibit this particular mode of deformation. We then experimentally validated this predication using a wide range of tools. We utilized a DOE user facility, the Center for Integrated Nanotechnology (CINT), to fabricate, for the first time, these

  16. Orientation-related deformation mechanisms of naturally deformed amphibole in amphibolite mylonites from the Diancang Shan, SW Yunnan, China

    NASA Astrophysics Data System (ADS)

    Cao, Shuyun; Liu, Junlai; Leiss, Bernd

    2010-05-01

    Sheared amphibolite rocks from Diancang Shan high-grade metamorphic complex along the Ailao Shan-Red River shear zone, southwestern Yunnan, China, show typical mylonitic microstructures. The mylonites are characterized by porphyroclastic microstructures and the ultramylonites are highly lineated with alternating amphibole- and quartzofeldspathic domains. Microstructural analysis and P/T estimation suggest that the amphibole grains in the mylonitic rocks are deformed and dynamically recrystallized at amphibolite facies. In the mylonitic amphibolites, there are two types of amphibole porphyroclasts, i.e. type I "hard" and type II "soft" porphyroclasts. They have their [001] crystallographic orientations subnormal and sub-parallel to the stretching lineation of the rocks, respectively. The two types of porphyroclasts show distinct deformation microstructures and sub-microstructures formed by various deformation mechanisms, which contribute in different ways to the generation of the fine-grained matrix. Shape preferred orientation analysis, misorientation analysis of the two types of porphyroclasts and new fine grains around them further prove the generation of the fine grains in matrix from the type II porphyroclasts. The type I "hard" porphyroclasts are deformed mainly by mechanical rotation, work hardening and intragranular microfracturing. In contrast, the deformation of the type II "soft" porphyroclasts is mainly attributed to crystalline plasticity, i.e. twinning, dislocation creep and dynamic recrystallization. During the deformation of the type II porphyroclasts, the (100) [001] slip system plays a dominant role during deformation and grain size reduction of amphibole. Twinning along the active (100) slip system, in combination with dislocation creep (gliding and climbing) governs the nucleation of subgrains and formation of dynamically recrystallized fine grains, a process here named Twinning Nucleation Recrystallization.

  17. Versatile Membrane Deformation Potential of Activated Pacsin

    PubMed Central

    Byrnes, Laura J.; Sondermann, Holger

    2012-01-01

    Endocytosis is a fundamental process in signaling and membrane trafficking. The formation of vesicles at the plasma membrane is mediated by the G protein dynamin that catalyzes the final fission step, the actin cytoskeleton, and proteins that sense or induce membrane curvature. One such protein, the F-BAR domain-containing protein pacsin, contributes to this process and has been shown to induce a spectrum of membrane morphologies, including tubules and tube constrictions in vitro. Full-length pacsin isoform 1 (pacsin-1) has reduced activity compared to its isolated F-BAR domain, implicating an inhibitory role for its C-terminal Src homology 3 (SH3) domain. Here we show that the autoinhibitory, intramolecular interactions in pacsin-1 can be released upon binding to the entire proline-rich domain (PRD) of dynamin-1, resulting in potent membrane deformation activity that is distinct from the isolated F-BAR domain. Most strikingly, we observe the generation of small, homogenous vesicles with the activated protein complex under certain experimental conditions. In addition, liposomes prepared with different methods yield distinct membrane deformation morphologies of BAR domain proteins and apparent activation barriers to pacsin-1's activity. Theoretical free energy calculations suggest bimodality of the protein-membrane system as a possible source for the different outcomes, which could account for the coexistence of energetically equivalent membrane structures induced by BAR domain-containing proteins in vitro. Taken together, our results suggest a versatile role for pacsin-1 in sculpting cellular membranes that is likely dependent both on protein structure and membrane properties. PMID:23236520

  18. Magnetite deformation mechanism maps for better prediction of strain partitioning

    NASA Astrophysics Data System (ADS)

    Till, J. L.; Moskowitz, Bruce

    2013-02-01

    Abstract A meta-analysis of existing experimental <span class="hlt">deformation</span> data for magnetite and other spinel-structured ferrites reveals that previously published flow laws are inadequate to describe the general <span class="hlt">deformation</span> behavior of magnetite. Using updated rate equations for oxygen diffusion in magnetite, we present new flow laws that closely predict creep rates similar to those found in <span class="hlt">deformation</span> experiments and that can be used to predict strain partitioning between cubic Fe oxides and other phases in the Earth's crust. New <span class="hlt">deformation</span> <span class="hlt">mechanism</span> maps for magnetite have been constructed as functions of temperature and grain size. Using the revised creep parameters, estimates of strain partitioning between magnetite, ilmenite, and plagioclase indicate that concentrated zones of Fe-Ti oxides in oceanic crust near slow-spreading ridges could accommodate significant amounts of strain at moderate temperatures and may contribute to aseismic creep along spreading-segment faults.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70030702','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70030702"><span id="translatedtitle">Inference of postseismic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of the 1923 Kanto earthquake</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Pollitz, F.F.; Nyst, M.; Nishimura, T.; Thatcher, W.</p> <p>2006-01-01</p> <p>Coseismic slip associated with the M7.9, 1923 Kanto earthquake is fairly well understood, involving slip of up to 8 m along the Philippine Sea-Honshu interplate boundary under Sagami Bay and its onland extension. Postseismic <span class="hlt">deformation</span> after the 1923 earthquake, however, is relatively poorly understood. We revisit the available <span class="hlt">deformation</span> data in order to constrain possible <span class="hlt">mechanisms</span> of postseismic <span class="hlt">deformation</span> and to examine the consequences for associated stress changes in the surrounding crust. Data from two leveling lines and one tide gage station over the first 7-8 years postseismic period are of much greater amplitude than the corresponding expected interseismic <span class="hlt">deformation</span> during the same period, making these data suitable for isolating the signal from postseismic <span class="hlt">deformation</span>. We consider both viscoelastic models of asthenosphere relaxation and afterslip models. A distributed coseismic slip model presented by Pollitz et al. (2005), combined with prescribed parameters of a viscoelastic Earth model, yields predicted postseismic <span class="hlt">deformation</span> that agrees with observed <span class="hlt">deformation</span> on mainland Honshu from Tokyo to the Izu peninsula. Elsewhere (southern Miura peninsula; Boso peninsula), the considered viscoelastic models fail to predict observed <span class="hlt">deformation</span>, and a model of ???1 in shallow afterslip in the offshore region south of the Boso peninsula, with equivalent moment magnitude Mw = 7.0, adequately accounts for the observed <span class="hlt">deformation</span>. Using the distributed coseismic slip model, layered viscoelastic structure, and a model of interseismic strain accumulation, we evaluate the post-1923 stress evolution, including both the coseismic and accumulated postseismic stress changes and those stresses contributed by interseismic loading. We find that if account is made for the varying tectonic regime in the region, the occurrence of both immediate (first month) post-1923 crustal aftershocks as well as recent regional crustal seismicity is consistent with the predicted</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5577060','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5577060"><span id="translatedtitle"><span class="hlt">Mechanical</span> threshold of dynamically <span class="hlt">deformed</span> copper and Nitronic 40</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Follansbee, P.S.; Kocks, U.F.; Regazzoni, G.</p> <p>1985-01-01</p> <p>Measurements of the <span class="hlt">mechanical</span> threshold, or threshold stress, are reported on quasi-statically and dynamically <span class="hlt">deformed</span> copper and Nitronic 40. Results for copper show that the increase of the threshold stress with strain rate is similar to that of the flow stress. In Nitronic 40 the results show that the ratio of the flow stress to the threshold stress is approx.0.6. Both results indicate that the increased rate sensitivity found in these materials at high strain rates is not due to the predominance of a viscous drag <span class="hlt">deformation</span> <span class="hlt">mechanism</span>, as has been previously suggested.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PIAHS.372..231C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PIAHS.372..231C"><span id="translatedtitle">Study of the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of the Gaoliying ground fissure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cheng, G.; Wang, H.; Luo, Y.; Guo, H.</p> <p>2015-11-01</p> <p>The Gaoliying ground fissure in Beijing has caused building cracking and road damage, and has seriously influenced city construction. Based on investigations and trenching, the influences of the fault and the variation of groundwater levels on the formation <span class="hlt">mechanism</span> of the Gaoliying ground fissure were investigated by using FLAC3D. The results indicated that (1) the surface location of Gaoliying fissure is controlled by the underlying normal fault <span class="hlt">activity</span>, and over pumping further exacerbates development of the ground fissure; (2) when the groundwater level declines, obvious differential settlement occurs at both sides of the ground fissure, in which greater settlement occurs in the vicinity of the hanging wall, the greater the distance from the hanging wall, the smaller the ground subsidence, however smaller ground subsidence occurs in the vicinity of the footwall, the greater the distance from the footwall, the greater the ground subsidence; (3) the vertical velocity of the ground fissure triggered by the fault <span class="hlt">activity</span> and groundwater decline ranges from 15.5 to 18.3 mm a-1, which is basically in line with the monitoring data. The fault <span class="hlt">activity</span> contributes about 28-39 %, and the groundwater contributes about 61-72 % to the <span class="hlt">deformation</span> of the ground fissure, respectively.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22273525','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22273525"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">deformations</span> of boron nitride nanotubes in crossed junctions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhao, Yadong; Chen, Xiaoming; Ke, Changhong; Park, Cheol; Fay, Catharine C.; Stupkiewicz, Stanislaw</p> <p>2014-04-28</p> <p>We present a study of the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of boron nitride nanotubes (BNNTs) in crossed junctions. The structure and <span class="hlt">deformation</span> of the crossed tubes in the junction are characterized by using atomic force microscopy. Our results show that the total tube heights are reduced by 20%–33% at the crossed junctions formed by double-walled BNNTs with outer diameters in the range of 2.21–4.67 nm. The measured tube height reduction is found to be in a nearly linear relationship with the summation of the outer diameters of the two tubes forming the junction. The contact force between the two tubes in the junction is estimated based on contact <span class="hlt">mechanics</span> theories and found to be within the range of 4.2–7.6 nN. The Young's modulus of BNNTs and their binding strengths with the substrate are quantified, based on the <span class="hlt">deformation</span> profile of the upper tube in the junction, and are found to be 1.07 ± 0.11 TPa and 0.18–0.29 nJ/m, respectively. Finally, we perform finite element simulations on the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of the crossed BNNT junctions. The numerical simulation results are consistent with both the experimental measurements and the analytical analysis. The results reported in this paper contribute to a better understanding of the structural and <span class="hlt">mechanical</span> properties of BNNTs and to the pursuit of their applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JAP...115p4305Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JAP...115p4305Z"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">deformations</span> of boron nitride nanotubes in crossed junctions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Yadong; Chen, Xiaoming; Park, Cheol; Fay, Catharine C.; Stupkiewicz, Stanislaw; Ke, Changhong</p> <p>2014-04-01</p> <p>We present a study of the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of boron nitride nanotubes (BNNTs) in crossed junctions. The structure and <span class="hlt">deformation</span> of the crossed tubes in the junction are characterized by using atomic force microscopy. Our results show that the total tube heights are reduced by 20%-33% at the crossed junctions formed by double-walled BNNTs with outer diameters in the range of 2.21-4.67 nm. The measured tube height reduction is found to be in a nearly linear relationship with the summation of the outer diameters of the two tubes forming the junction. The contact force between the two tubes in the junction is estimated based on contact <span class="hlt">mechanics</span> theories and found to be within the range of 4.2-7.6 nN. The Young's modulus of BNNTs and their binding strengths with the substrate are quantified, based on the <span class="hlt">deformation</span> profile of the upper tube in the junction, and are found to be 1.07 ± 0.11 TPa and 0.18-0.29 nJ/m, respectively. Finally, we perform finite element simulations on the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of the crossed BNNT junctions. The numerical simulation results are consistent with both the experimental measurements and the analytical analysis. The results reported in this paper contribute to a better understanding of the structural and <span class="hlt">mechanical</span> properties of BNNTs and to the pursuit of their applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhA...48R5208O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhA...48R5208O"><span id="translatedtitle">Sine-square <span class="hlt">deformation</span> and supersymmetric quantum <span class="hlt">mechanics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okunishi, Kouichi; Katsura, Hosho</p> <p>2015-11-01</p> <p>We investigate the sine-square <span class="hlt">deformation</span> (SSD) of free fermions in one-dimensional continuous space. On the basis of supersymmetric quantum <span class="hlt">mechanics</span>, we prove the correspondence between the many-body ground state of the system with SSD and that of the uniform system with periodic boundary conditions. We also discuss the connection between the SSD in the continuous space and its lattice version, where the geometric correction due to the real-space <span class="hlt">deformation</span> plays an important role in relating the eigenstates of the lattice SSD with those of the continuous SSD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930018132','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930018132"><span id="translatedtitle"><span class="hlt">Deformation</span> of supersymmetric and conformal quantum <span class="hlt">mechanics</span> through affine transformations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spiridonov, Vyacheslav</p> <p>1993-01-01</p> <p>Affine transformations (dilatations and translations) are used to define a <span class="hlt">deformation</span> of one-dimensional N = 2 supersymmetric quantum <span class="hlt">mechanics</span>. Resulting physical systems do not have conserved charges and degeneracies in the spectra. Instead, superpartner Hamiltonians are q-isospectral, i.e. the spectrum of one can be obtained from another (with possible exception of the lowest level) by q(sup 2)-factor scaling. This construction allows easily to rederive a special self-similar potential found by Shabat and to show that for the latter a q-<span class="hlt">deformed</span> harmonic oscillator algebra of Biedenharn and Macfarlane serves as the spectrum generating algebra. A general class of potentials related to the quantum conformal algebra su(sub q)(1,1) is described. Further possibilities for q-<span class="hlt">deformation</span> of known solvable potentials are outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22271185','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22271185"><span id="translatedtitle">Temperature dependent <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in pure amorphous silicon</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kiran, M. S. R. N. Haberl, B.; Williams, J. S.; Bradby, J. E.</p> <p>2014-03-21</p> <p>High temperature nanoindentation has been performed on pure ion-implanted amorphous silicon (unrelaxed a-Si) and structurally relaxed a-Si to investigate the temperature dependence of <span class="hlt">mechanical</span> <span class="hlt">deformation</span>, including pressure-induced phase transformations. Along with the indentation load-depth curves, ex situ measurements such as Raman micro-spectroscopy and cross-sectional transmission electron microscopy analysis on the residual indents reveal the mode of <span class="hlt">deformation</span> under the indenter. While unrelaxed a-Si <span class="hlt">deforms</span> entirely via plastic flow up to 200 °C, a clear transition in the mode of <span class="hlt">deformation</span> is observed in relaxed a-Si with increasing temperature. Up to 100 °C, pressure-induced phase transformation and the observation of either crystalline (r8/bc8) end phases or pressure-induced a-Si occurs in relaxed a-Si. However, with further increase of temperature, plastic flow rather than phase transformation is the dominant mode of <span class="hlt">deformation</span>. It is believed that the elevated temperature and pressure together induce bond softening and “defect” formation in structurally relaxed a-Si, leading to the inhibition of phase transformation due to pressure-releasing plastic flow under the indenter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25003518','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25003518"><span id="translatedtitle">Analysis of internal crack healing <span class="hlt">mechanism</span> under rolling <span class="hlt">deformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gao, Haitao; Ai, Zhengrong; Yu, Hailiang; Wu, Hongyan; Liu, Xianghua</p> <p>2014-01-01</p> <p>A new experimental method, called the 'hole filling method', is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing <span class="hlt">mechanism</span>. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic <span class="hlt">deformation</span>, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic <span class="hlt">deformation</span> followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion <span class="hlt">mechanism</span> is used to explain the source of material needed for crack healing. The recrystallisation <span class="hlt">mechanism</span> is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface. PMID:25003518</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MAR.A5011C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MAR.A5011C"><span id="translatedtitle">Effects of interatomic potentials on <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of glasses</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, Wei-Ren; Iwashita, Takuya; Egami, Takeshi</p> <p>2013-03-01</p> <p>Apparently glasses behave like an elastic solid, which shows a linear relationship between stress and strain in <span class="hlt">mechanical</span> <span class="hlt">deformation</span>. However the understanding of the <span class="hlt">mechanical</span> response of glasses remains elusive because of structural disorder. <span class="hlt">Mechanical</span> <span class="hlt">deformation</span> of monatomic model glasses was studied using athermal quasi-static shear (AQS) simulation and with three different potentials. As the interatomic potentials we employed the 12-6 Lennard-Jones (LJ) potential, modified Johnson (mJ) potential, and Dzugutov (Dz) potential, respectively. For mJ and Dz glasses the shear modulus keeps constant below a critical strain, below which it decreases rapidly or discontinuously with strain. Such changes in shear modulus were mostly related to the change in local topology of atomic connectivity or anelasticity. In contrast LJ glass shows a gradual decrease in shear modulus in a continuous manner. The results indicated that the difference arises from the nature of the potentials if the topology of atomic connectivity can be clearly defined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4086985','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4086985"><span id="translatedtitle">Analysis of Internal Crack Healing <span class="hlt">Mechanism</span> under Rolling <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Gao, Haitao; Ai, Zhengrong; Yu, Hailiang; Wu, Hongyan; Liu, Xianghua</p> <p>2014-01-01</p> <p>A new experimental method, called the ‘hole filling method’, is proposed to simulate the healing of internal cracks in rolled workpieces. Based on the experimental results, the evolution in the microstructure, in terms of diffusion, nucleation and recrystallisation were used to analyze the crack healing <span class="hlt">mechanism</span>. We also validated the phenomenon of segmented healing. Internal crack healing involves plastic <span class="hlt">deformation</span>, heat transfer and an increase in the free energy introduced by the cracks. It is proposed that internal cracks heal better under high plastic <span class="hlt">deformation</span> followed by slow cooling after rolling. Crack healing is controlled by diffusion of atoms from the matrix to the crack surface, and also by the nucleation and growth of ferrite grain on the crack surface. The diffusion <span class="hlt">mechanism</span> is used to explain the source of material needed for crack healing. The recrystallisation <span class="hlt">mechanism</span> is used to explain grain nucleation and growth, accompanied by atomic migration to the crack surface. PMID:25003518</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARE17005L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARE17005L"><span id="translatedtitle">Tuning transport properties on graphene multiterminal structures by <span class="hlt">mechanical</span> <span class="hlt">deformations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Latge, Andrea; Torres, Vanessa; Faria, Daiara</p> <p></p> <p>The realization of <span class="hlt">mechanical</span> strain on graphene structures is viewed as a promise route to tune electronic and transport properties such as changing energy band-gaps and promoting localization of states. Using continuum models, <span class="hlt">mechanical</span> <span class="hlt">deformations</span> are described by effective gauge fields, mirrored as pseudomagnetic fields that may reach quite high values. Interesting symmetry features are developed due to out of plane <span class="hlt">deformations</span> on graphene; lift sublattice symmetry was predicted and observed in centrosymmetric bumps and strained nanobubbles. Here we discuss the effects of Gaussian-like strain on a hexagonal graphene flake connected to three leads, modeled as perfect graphene nanoribbons. The Green function formalism is used within a tight-binding approximation. For this particular <span class="hlt">deformation</span> sharp resonant states are achieved depending on the strained structure details. We also study a fold-strained structure in which the three leads are <span class="hlt">deformed</span> extending up to the very center of the hexagonal flake. We show that conductance suppressions can be controlled by the strain intensity and important transport features are modeled by the electronic band structure of the leads.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010SPIE.7997E..1BM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010SPIE.7997E..1BM"><span id="translatedtitle"><span class="hlt">Mechanical</span> bearing bore similarity law of non-thermal <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miao, Enming; Niu, Pengcheng; Ji, Xianrui; Lin, Nan; Fei, Yetai</p> <p>2010-12-01</p> <p>The gear transmission is widely used in <span class="hlt">mechanical</span> engineering. During the work time, the size of the bearing hole has changed due to temperature increase, leading to the size, shape and position tolerances of shaft and bearing with the components deviates from the original design requirements, thus making the spatial location of axis , gear with the gap and tooth contact angle changed, noise increasing, gear life shorten. In this paper, the thermal <span class="hlt">deformation</span> experiments of the commonly used <span class="hlt">mechanical</span> engineering machinery bearing hole has been carrying on. Using self-developed experimental device, in the -10 ~ 80°C temperature range, a single hole is measured accurately on the different radial direct, and measurement data is analyzed, combined with the structure and size of surrounding of hole. The results of theory and test analysis show that the thermal <span class="hlt">deformation</span> feature of hole is not only closely related to the physical attributes of material, but still affected by its own structure and size of parts. That means thermal <span class="hlt">deformation</span> of parts has non-similar thermal <span class="hlt">deformation</span> features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.7997E..1BM','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.7997E..1BM"><span id="translatedtitle"><span class="hlt">Mechanical</span> bearing bore similarity law of non-thermal <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miao, Enming; Niu, Pengcheng; Ji, Xianrui; Lin, Nan; Fei, Yetai</p> <p>2011-05-01</p> <p>The gear transmission is widely used in <span class="hlt">mechanical</span> engineering. During the work time, the size of the bearing hole has changed due to temperature increase, leading to the size, shape and position tolerances of shaft and bearing with the components deviates from the original design requirements, thus making the spatial location of axis , gear with the gap and tooth contact angle changed, noise increasing, gear life shorten. In this paper, the thermal <span class="hlt">deformation</span> experiments of the commonly used <span class="hlt">mechanical</span> engineering machinery bearing hole has been carrying on. Using self-developed experimental device, in the -10 ~ 80°C temperature range, a single hole is measured accurately on the different radial direct, and measurement data is analyzed, combined with the structure and size of surrounding of hole. The results of theory and test analysis show that the thermal <span class="hlt">deformation</span> feature of hole is not only closely related to the physical attributes of material, but still affected by its own structure and size of parts. That means thermal <span class="hlt">deformation</span> of parts has non-similar thermal <span class="hlt">deformation</span> features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1049842','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1049842"><span id="translatedtitle">Structural Anisotropy in Metallic Glasses Induced by <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Dmowski, Wojtek; Egami, Takeshi</p> <p>2008-01-01</p> <p>Metallic glasses have been studied vigorously since the first report on amorphous gold-silicon alloy back in 1960.[1] Initially soft magnetic properties were the most promising features for industrial applications. The recent development of bulk metallic glasses (BMGs)[2 5] initiated interests in engineering applications such as structural or biomedical materials because of attractive properties such as high strength,[6] high elasticity,[7,8] and good corrosion resistance,[9,10] among others. In addition, high temperature processing of BMGs allows for near-net-shape formability,[11 13] which could simplify and possibly reduce the cost of the final product. The glasses retain the disordered atomic structure of a liquid, and ideally are isotropic solids. Frequently because of processing conditions, such as directional heat flow, some structural anisotropy is produced during quenching, and has been observed by structural investigations. Usually, annealing at high temperatures results in an isotropic structure. Also, formation of uniaxial magnetic anisotropy[14] had been observed in studies of creep <span class="hlt">deformed</span> ferromagnetic metallic glasses. Samples with a near-zero magnetostriction coefficient had been studied to establish the origin of the magnetic anisotropy. It was concluded that anisotropy resulted from the atomic level anisotropy[15] and not the heterogeneous internal stress distribution. Indeed X-ray diffraction study of the creep <span class="hlt">deformed</span> metallic glass showed bond anisotropy.[ 16,17] Such structural studies had been cumbersome and lengthy because they required measurement of many orientations with high statistics. Recently we have shown that use of an area detector and high energy X-rays at a synchrotron source can speed up data collection without compromising statistics.[18] In this contribution, we present data showing structural anisotropy in glassy samples after homogenous (creep) and inhomogeneous (compression) <span class="hlt">mechanical</span> <span class="hlt">deformation</span>. The observation of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanos...814420D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanos...814420D&link_type=ABSTRACT"><span id="translatedtitle">Nanoparticle <span class="hlt">mechanics</span>: <span class="hlt">deformation</span> detection via nanopore resistive pulse sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Darvish, Armin; Goyal, Gaurav; Aneja, Rachna; Sundaram, Ramalingam V. K.; Lee, Kidan; Ahn, Chi Won; Kim, Ki-Bum; Vlahovska, Petia M.; Kim, Min Jun</p> <p>2016-07-01</p> <p>Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such <span class="hlt">deformations</span> can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the <span class="hlt">deformation</span> of various liposomes inside nanopores. We observed a significant difference in resistive pulse characteristics between soft liposomes and rigid polystyrene nanoparticles especially at higher applied voltages. We used theoretical simulations to demonstrate that the difference can be explained by shape <span class="hlt">deformation</span> of liposomes as they translocate through the nanopores. Comparing our results with the findings from electrodeformation experiments, we demonstrated that the rigidity of liposomes can be qualitatively compared using resistive pulse characteristics. This application of nanopores can provide new opportunities to study the <span class="hlt">mechanics</span> at the nanoscale, to investigate properties of great value in fundamental biophysics and cellular mechanobiology, such as virus <span class="hlt">deformability</span> and fusogenicity, and in applied sciences for designing novel drug/gene delivery systems.Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such <span class="hlt">deformations</span> can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the <span class="hlt">deformation</span> of various</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARS35005T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARS35005T"><span id="translatedtitle">Discontinuous fluidization transition in dense suspensions of <span class="hlt">actively</span> <span class="hlt">deforming</span> particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tjhung, Elsen; Berthier, Ludovic</p> <p></p> <p>Collective dynamics of self-propelled particles at high density have been shown to display a glass-like transition with a critical slowing down of 2 to 4 orders of magnitude. In this talk, we propose a new <span class="hlt">mechanism</span> of injecting energy or <span class="hlt">activity</span> via volume fluctuations. We show that the behaviour of <span class="hlt">actively</span> <span class="hlt">deforming</span> particles is strikingly different from that of self-propelled particles. In particular, we find a discontinuous non-equilibrium phase transition from a flowing state to an arrested state. Our minimal model might also explain the collective dynamics in epithelial tissues. In particular, without needing self-propulsion or cell-cell adhesion, volume fluctuations of individual cells alone might be sufficient to give rise to an <span class="hlt">active</span> fluidization and collective dynamics in densely packed tissues.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27321911','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27321911"><span id="translatedtitle">Nanoparticle <span class="hlt">mechanics</span>: <span class="hlt">deformation</span> detection via nanopore resistive pulse sensing.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Darvish, Armin; Goyal, Gaurav; Aneja, Rachna; Sundaram, Ramalingam V K; Lee, Kidan; Ahn, Chi Won; Kim, Ki-Bum; Vlahovska, Petia M; Kim, Min Jun</p> <p>2016-08-14</p> <p>Solid-state nanopores have been widely used in the past for single-particle analysis of nanoparticles, liposomes, exosomes and viruses. The shape of soft particles, particularly liposomes with a bilayer membrane, can greatly differ inside the nanopore compared to bulk solution as the electric field inside the nanopores can cause liposome electrodeformation. Such <span class="hlt">deformations</span> can compromise size measurement and characterization of particles, but are often neglected in nanopore resistive pulse sensing. In this paper, we investigated the <span class="hlt">deformation</span> of various liposomes inside nanopores. We observed a significant difference in resistive pulse characteristics between soft liposomes and rigid polystyrene nanoparticles especially at higher applied voltages. We used theoretical simulations to demonstrate that the difference can be explained by shape <span class="hlt">deformation</span> of liposomes as they translocate through the nanopores. Comparing our results with the findings from electrodeformation experiments, we demonstrated that the rigidity of liposomes can be qualitatively compared using resistive pulse characteristics. This application of nanopores can provide new opportunities to study the <span class="hlt">mechanics</span> at the nanoscale, to investigate properties of great value in fundamental biophysics and cellular mechanobiology, such as virus <span class="hlt">deformability</span> and fusogenicity, and in applied sciences for designing novel drug/gene delivery systems. PMID:27321911</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT........17U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........17U"><span id="translatedtitle">On the creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of an advanced disk nickel-base superalloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Unocic, Raymond R.</p> <p></p> <p> <span class="hlt">activated</span> climb/bypass <span class="hlt">mechanism</span> of a/2<110> dislocations were found to be the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. In this <span class="hlt">mechanism</span>, the gamma' precipitates were not sheared but instead were bypassed by a/2<110> matrix dislocations. In addition to the identification of creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> as a function of stress and temperature, characterization of the post creep gamma' precipitate microstructure revealed that microstructural evolution of the gamma' precipitates has occurred during creep at the higher test temperatures where the secondary gamma' precipitates have coarsened and the tertiary gamma' precipitates have dissolved. In combination with creep at low stress and high temperature, the microstructural evolution may have contributed to the transition from one <span class="hlt">deformation</span> mode to another. In an attempt to link the influence of microstructure (gamma' precipitate size scale, distribution, volume fraction, and gamma channel width spacing) on creep <span class="hlt">deformation</span> behavior and creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, specimens with different size scaled microstructural features were crept at the same temperature and stress (677°C and 724MPa) in order to provide a direct comparison between differences in microstructure. It was found that a microstructure consisting of a bimodal distribution of gamma' precipitates with coarse secondary gamma' precipitates, a high volume fraction of tertiary gamma' precipitates and a wide gamma channel width spacing results in a less creep resistance microstructure that <span class="hlt">deformed</span> primary by a/2<110> dislocation <span class="hlt">activity</span> in the gamma matrix at small strain and secondary gamma' shearing via superlattice intrinsic stacking faults at higher strains. The more creep resistant microstructure consisted of a bimodal distribution of gamma' precipitates with a finer secondary gamma' precipitate size, low volume fraction of gamma' and narrow gamma channel width spacing. The combination of these microstructural features promoted a/2<110> dislocation dissociation and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1185511','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1185511"><span id="translatedtitle">Unraveling cyclic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a rolled magnesium alloy using in situ neutron diffraction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wu, Wei; An, Ke; Liaw, Peter K.</p> <p>2014-12-23</p> <p>In the current study, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a rolled magnesium alloy were investigated under cyclic loading using real-time in situ neutron diffraction under a continuous-loading condition. The relationship between the macroscopic cyclic <span class="hlt">deformation</span> behavior and the microscopic response at the grain level was established. The neutron diffraction results indicate that more and more grains are involved in the twinning and detwinning <span class="hlt">deformation</span> process with the increase of fatigue cycles. The residual twins appear in the early fatigue life, which is responsible for the cyclic hardening behavior. The asymmetric shape of the hysteresis loop is attributed to the early exhaustion of the detwinning process during compression, which leads to the <span class="hlt">activation</span> of dislocation slips and rapid strain-hardening. The critical resolved shear stress for the <span class="hlt">activation</span> of tensile twinning closely depends on the residual strain developed during cyclic loading. In the cycle before the sample fractured, the dislocation slips became <span class="hlt">active</span> in tension, although the sample was not fully twinned. The increased dislocation density leads to the rise of the stress concentration at weak spots, which is believed to be the main reason for the fatigue failure. Furthermore, the <span class="hlt">deformation</span> history greatly influences the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of hexagonal-close-packed-structured magnesium alloy during cyclic loading.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1185511-unraveling-cyclic-deformation-mechanisms-rolled-magnesium-alloy-using-situ-neutron-diffraction','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1185511-unraveling-cyclic-deformation-mechanisms-rolled-magnesium-alloy-using-situ-neutron-diffraction"><span id="translatedtitle">Unraveling cyclic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a rolled magnesium alloy using in situ neutron diffraction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wu, Wei; An, Ke; Liaw, Peter K.</p> <p>2014-12-23</p> <p>In the current study, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a rolled magnesium alloy were investigated under cyclic loading using real-time in situ neutron diffraction under a continuous-loading condition. The relationship between the macroscopic cyclic <span class="hlt">deformation</span> behavior and the microscopic response at the grain level was established. The neutron diffraction results indicate that more and more grains are involved in the twinning and detwinning <span class="hlt">deformation</span> process with the increase of fatigue cycles. The residual twins appear in the early fatigue life, which is responsible for the cyclic hardening behavior. The asymmetric shape of the hysteresis loop is attributed to the early exhaustionmore » of the detwinning process during compression, which leads to the <span class="hlt">activation</span> of dislocation slips and rapid strain-hardening. The critical resolved shear stress for the <span class="hlt">activation</span> of tensile twinning closely depends on the residual strain developed during cyclic loading. In the cycle before the sample fractured, the dislocation slips became <span class="hlt">active</span> in tension, although the sample was not fully twinned. The increased dislocation density leads to the rise of the stress concentration at weak spots, which is believed to be the main reason for the fatigue failure. Furthermore, the <span class="hlt">deformation</span> history greatly influences the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of hexagonal-close-packed-structured magnesium alloy during cyclic loading.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhRvD..88h4009C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhRvD..88h4009C"><span id="translatedtitle">Generalized coherent states under <span class="hlt">deformed</span> quantum <span class="hlt">mechanics</span> with maximum momentum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ching, Chee Leong; Ng, Wei Khim</p> <p>2013-10-01</p> <p>Following the Gazeau-Klauder approach, we construct generalized coherent states (GCS) as the quantum simulator to examine the <span class="hlt">deformed</span> quantum <span class="hlt">mechanics</span>, which exhibits an intrinsic maximum momentum. We study <span class="hlt">deformed</span> harmonic oscillators and compute their probability distribution and entropy of states exactly. Also, a particle in an infinite potential box is studied perturbatively. In particular, unlike usual quantum <span class="hlt">mechanics</span>, the present <span class="hlt">deformed</span> case increases the entropy of the Planck scale quantum optical system. Furthermore, for simplicity, we obtain the modified uncertainty principle (MUP) with the perturbative treatment up to leading order. MUP turns out to increase generally. However, for certain values of γ (a parameter of GCS), it is possible that the MUP will vanish and hence will exhibit the classical characteristic. This is interpreted as the manifestation of the intrinsic high-momentum cutoff at lower momentum in a perturbative treatment. Although the GCS saturates the minimal uncertainty in a simultaneous measurement of physical position and momentum operators, thus constituting the squeezed states, complete coherency is impossible in quantum gravitational physics. The Mandel Q number is calculated, and it is shown that the statistics can be Poissonian and super-/sub-Poissonian depending on γ. The equation of motion is studied, and both Ehrenfest’s theorem and the correspondence principle are recovered. Fractional revival times are obtained through the autocorrelation, and they indicate that the superposition of a classical-like subwave packet is natural in GCS. We also contrast our results with the string-motivated (Snyder) type of <span class="hlt">deformed</span> quantum <span class="hlt">mechanics</span>, which incorporates a minimum position uncertainty rather than a maximum momentum. With the advances of quantum optics technology, it might be possible to realize some of these distinguishing quantum-gravitational features within the domain of future experiments.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1172459','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1172459"><span id="translatedtitle">A <span class="hlt">Mechanism</span>-based Model for <span class="hlt">Deformation</span> Twinning in Polycrystalline FCC Steel</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wang, Yuan; Sun, Xin; Wang, Y. D.; Hu, Xiaohua; Zbib, Hussein M.</p> <p>2014-06-01</p> <p><span class="hlt">Deformation</span> twinning, a common and important plastic <span class="hlt">deformation</span> <span class="hlt">mechanism</span>, is the key contributor to the excellent combination of strength and ductility in twinning-induced plasticity (TWIP) steel. In the open literature, a significant amount of research has been reported on the microstructural characteristics of <span class="hlt">deformation</span> twinning and its influence on the overall <span class="hlt">deformation</span> behavior of TWIP steel. In this study, we examine the feasibility of a <span class="hlt">mechanism</span>-based crystal plasticity model in simulating the microstructural level <span class="hlt">deformation</span> characteristics of TWIP steel. To this end, a model considering both double-slip and double-twin is developed to investigate the stress-strain behavior and local microstructural features related to the formation and growth of micro-twins in low stacking fault energy (SFE) TWIP steel. The twin systems are described as pseudo-slips that can be <span class="hlt">activated</span> when their resolved shear stress reaches the corresponding critical value. A hardening law that accounts for the interaction among the slip and twin systems is also developed. Numerical simulations for dDifferent mesh sizes and single crystal patch tests under different loading modes are carried out to verify the modeling procedure. Our simulation results reveal that, despite its simple nature, the double-slip/double-twin model can capture the key <span class="hlt">deformation</span> features of TWIP steel, including twin volume fraction evolution, continuous strain hardening, and the final fracture in the form of strain localization.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.5330G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.5330G"><span id="translatedtitle">Rotational <span class="hlt">Deformation</span> near Major Faults: A New <span class="hlt">Mechanical</span> Approach for Connecting Paleomagnetic and Geodetic Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ginsburg, Neta; Hamiel, Yariv; Granot, Roi</p> <p>2015-04-01</p> <p>Vertical axis rotations are a significant component of crustal <span class="hlt">deformation</span> and provide important constraints on the tectonic history of plate boundaries. Geodetic measurements can be used to calculate present-day rotations whereas paleomagnetic measurements can be used for calculating finite long-term (millions of years) rotations. Here we present a new approach for integrating both datasets through <span class="hlt">mechanical</span> modeling that links these time scales. We test this approach in northern Israel, a region where a tectonic triple junction lies at the intersection between two <span class="hlt">deformation</span> zones: (1) The Dead Sea Fault, and (2) The Carmel-Gilboa Fault System. We examined the temporal and spatial distribution of crustal <span class="hlt">deformation</span> and rotation rates near these two major fault zones. First, rotation rates were calculated from current interseismic global positioning system (GPS) measurements that were recorded during 12 years. We analyzed the GPS velocities using a 3D dislocation slip model that takes into account motion on major <span class="hlt">active</span> faults in the study area. This model was then modified to account for the total <span class="hlt">deformation</span> of the crust. Rotations from the <span class="hlt">mechanical</span> modeling were compared against finite rotations determined based on primary magnetic remanence directions from 30 Neogenic basaltic sites. Paleomagnetic results indicate significant (>20°) rotations near the edges of fault segments. These results disagree with interseismic rotations calculated from the GPS measurements; however they are in general agreement with the vertical axis rotations obtained from the <span class="hlt">mechanical</span> model. The comparison to the modified model suggests that the tectonic setting of the Carmel-Gilboa Fault system was fairly stable during the last 6.5-8 Myr. Furthermore, the new suggested method for comparing interseismic recent <span class="hlt">deformation</span> with long-term <span class="hlt">deformation</span> provides important new insights on the timing, magnitude and style of <span class="hlt">deformation</span> near major faults and can be used for locating</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..1110039A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..1110039A"><span id="translatedtitle">Experimental <span class="hlt">Deformation</span> of Diopside Single Crystals at Mantle P and T: <span class="hlt">Mechanical</span> Data and <span class="hlt">Deformation</span> Microstructures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Amiguet, E.; Raterron, P.; Cordier, P.; Couvy, H.; Chen, J.</p> <p>2009-04-01</p> <p>Clinopyroxenes (cpx) are major constituents of eclogites and are present in excess of 10 vol.% at most depths in the pyrolitic upper mantle. Among mantle minerals, they exhibit the strongest anisotropy for seismic wave propagation. Cpx plastic properties may thus significantly affect both mantle rheology and seismic anisotropy. Yet, no study of cpx rheology at high-pressure (typically P > 3 GPa) has been reported so far, while recent developments in high-pressure <span class="hlt">deformation</span> devices coupled with synchrotron radiation allow now investigating the rheology of mantle minerals and aggregates at the extreme pressure and temperature (T) of their natural occurrence in the Earth. In order to investigate the effect of P on cpx rheology, steady state <span class="hlt">deformation</span> experiments were carried out on gem quality oriented diopside crystals in the <span class="hlt">Deformation</span>-DIA apparatus (D-DIA, see Wang et al., 2003, Rev. Scientific Instr., 74, 3002) that equipped the X17B2 beamline of the NSLS (Upton, NY, USA), at P ranging from 3.8 to 8.8 GPa, T in the range 1100˚ -1400˚ C, and with differential stress () ranging between 0.2 and 1.7 GPa. Three compression directions were chosen in order to <span class="hlt">activate</span> either 1 •2 {1¯10} dislocation slip (duplex) systems together, or [100](010) and [010](100) systems together, or again [001] dislocation slip in (100), (010) and {110} planes. Constant and specimen strain rates (ɛ˙) were monitored in situ using time-resolved synchrotron X-ray diffraction and radiography, respectively. Transmission electron microscopy (TEM) investigation of the run products revealed that dislocation creep was responsible for sample <span class="hlt">deformation</span>. Comparison of the present high-P <span class="hlt">deformation</span> data with data obtained at room-P - on similar diopside crystals <span class="hlt">deformed</span> at comparable T- conditions (Raterron and Jaoul, 1991, JGR, 96, 14277) - allows quantifying the effect of P on the <span class="hlt">activity</span> of 1 •2 {1¯10} duplex systems. This translates into an <span class="hlt">activation</span> volume V * = 17 ± 6 cm</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23290516','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23290516"><span id="translatedtitle"><span class="hlt">Deformation</span> behavior and <span class="hlt">mechanical</span> properties of amyloid protein nanowires.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Solar, Max; Buehler, Markus J</p> <p>2013-03-01</p> <p>Amyloid fibrils are most often associated with their pathological role in diseases like Alzheimer's disease and Parkinson's disease, but they are now increasingly being considered for uses in functional engineering materials. They are among the stiffest protein fibers known but they are also rather brittle, and it is unclear how this combination of properties affects the behavior of amyloid structures at larger length scales, such as in films, wires or plaques. Using a coarse-grained model for amyloid fibrils, we study the <span class="hlt">mechanical</span> response of amyloid nanowires and examine fundamental <span class="hlt">mechanical</span> properties, including <span class="hlt">mechanisms</span> of <span class="hlt">deformation</span> and failure under tensile loading. We also explore the effect of varying the breaking strain and adhesion strength of the constituent amyloid fibrils on the properties of the larger structure. We find that <span class="hlt">deformation</span> in the nanowires is controlled by a combination of fibril sliding and fibril failure and that there exists a transition from brittle to ductile behavior by either increasing the fibril failure strain or decreasing the strength of adhesion between fibrils. Furthermore, our results reveal that the <span class="hlt">mechanical</span> properties of the nanowires are quite sensitive to changes in the properties of the individual fibrils, and the larger scale structures are found to be more <span class="hlt">mechanically</span> robust than the constituent fibrils, for all cases considered. More broadly, this work demonstrates the promise of utilizing self-assembled biological building blocks in the development of hierarchical nanomaterials. PMID:23290516</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19960007619','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19960007619"><span id="translatedtitle">Temperature Dependent Cyclic <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Haynes 188 Superalloy</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rao, K. Bhanu Sankara; Castelli, Michael G.; Allen, Gorden P.; Ellis, John R.</p> <p>1995-01-01</p> <p>The cyclic <span class="hlt">deformation</span> behavior of a wrought cobalt-base superalloy, Haynes 188, has been investigated over a range of temperatures between 25 and 1000 C under isothermal and in-phase thermomechanical fatigue (TMF) conditions. Constant <span class="hlt">mechanical</span> strain rates (epsilon-dot) of 10(exp -3)/s and 10(exp -4)/s were examined with a fully reversed strain range of 0.8%. Particular attention was given to the effects of dynamic strain aging (DSA) on the stress-strain response and low cycle fatigue life. A correlation between cyclic <span class="hlt">deformation</span> behavior and microstructural substructure was made through detailed transmission electron microscopy. Although DSA was found to occur over a wide temperature range between approximately 300 and 750 C the microstructural characteristics and the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> responsible for DSA varied considerably and were dependent upon temperature. In general, the operation of DSA processes led to a maximum of the cyclic stress amplitude at 650 C and was accompanied by pronounced planar slip, relatively high dislocation density, and the generation of stacking faults. DSA was evidenced through a combination of phenomena, including serrated yielding, an inverse dependence of the maximum cyclic hardening with epsilon-dot, and an instantaneous inverse epsilon-dot sensitivity verified by specialized epsilon-dot -change tests. The TMF cyclic hardening behavior of the alloy appeared to be dictated by the substructural changes occuring at the maximum temperature in the TMF cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1813444H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1813444H"><span id="translatedtitle">Thermal and <span class="hlt">mechanical</span> controls on magma supply and volcanic <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hickey, James; Gottsmann, Jo; Nakamichi, Haruhisa; Iguchi, Masato</p> <p>2016-04-01</p> <p>Ground <span class="hlt">deformation</span> often precedes volcanic eruptions, and results from complex interactions between source processes and the thermomechanical behaviour of surrounding rock. Geodetic models aimed at constraining source processes consequently require the implementation of realistic <span class="hlt">mechanical</span> and thermal rock properties. However, most generic models ignore this requirement and employ oversimplified <span class="hlt">mechanical</span> assumptions without regard for thermal effects. Here we show how spatio-temporal <span class="hlt">deformation</span> and magma reservoir evolution are fundamentally controlled by three-dimensional thermomechanical heterogeneity. Using the example of continued inflation at Aira caldera, Japan, we demonstrate that despite on-going eruptions magma is accumulating faster than it can be ejected, and the current uplift is approaching the level inferred prior to the 1914 Plinian eruption. Our results from inverse and forward numerical models are consistent with petrological constraints and highlight how the location, volume, and rate of magma supply, 0.014 km3/yr, are thermomechanically controlled. Magma storage conditions coincide with estimates for the caldera-forming reservoir ˜29,000 years ago, and the inferred magma supply rate indicates a ˜130-year timeframe to amass enough magma to feed a future 1914-sized eruption. These new inferences are important for eruption forecasting and risk mitigation, and have significant implications for the interpretations of volcanic <span class="hlt">deformation</span> worldwide.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24283329','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24283329"><span id="translatedtitle">Atomic force microscopic study of the structure of high-density polyethylene <span class="hlt">deformed</span> in liquid medium by crazing <span class="hlt">mechanism</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bagrov, D V; Yarysheva, A Y; Rukhlya, E G; Yarysheva, L M; Volynskii, A L; Bakeev, N F</p> <p>2014-02-01</p> <p>A procedure has been developed for the direct atomic force microscopic (AFM) examination of the native structure of high-density polyethylene (HDPE) <span class="hlt">deformed</span> in an adsorption-<span class="hlt">active</span> liquid medium (AALM) by the crazing <span class="hlt">mechanism</span>. The AFM investigation has been carried out in the presence of a liquid medium under conditions preventing <span class="hlt">deformed</span> films from shrinkage. <span class="hlt">Deformation</span> of HDPE in AALM has been shown to proceed through the delocalized crazing <span class="hlt">mechanism</span> and result in the development of a fibrillar-porous structure. The structural parameters of the crazed polymer have been determined. The obtained AFM images demonstrate a nanosized nonuniformity of the <span class="hlt">deformation</span> and enable one to observe the structural rearrangements that take place in the <span class="hlt">deformed</span> polymer after removal of the liquid medium and stress relaxation. A structural similarity has been revealed between HDPE <span class="hlt">deformed</span> in the AALM and hard elastic polymers. PMID:24283329</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15949544','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15949544"><span id="translatedtitle">The effect of crystallinity on the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> and bulk <span class="hlt">mechanical</span> properties of PLLA.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Renouf-Glauser, Annette C; Rose, John; Farrar, David F; Cameron, Ruth Elizabeth</p> <p>2005-10-01</p> <p>Poly (l-lactide) is a widely studied biomaterial, currently approved for use in a range of medical devices, however, most in vitro studies have so far focussed upon either the bulk properties during degradation and/or <span class="hlt">deformation</span>, or on the microstructure of the unloaded material during degradation. This study aimed to combine these approaches through the technique of simultaneous small-angle X-ray scattering and tensile testing at various stages of degradation up to 8 months, on material with a range of induced microstructures. Results showed that the amorphous material <span class="hlt">deformed</span> by crazing in the dry, wet and degraded states, however, the <span class="hlt">mechanism</span> by which the craze developed changed significantly on hydration. Despite this difference, there was little change in the bulk <span class="hlt">mechanical</span> properties. Crystalline materials <span class="hlt">deformed</span> through crystal-mediated <span class="hlt">deformation</span>, with contributions from both cavitation and fibrillated shear, but surprisingly, differences in the length scales within the spherulitic structure caused by annealing at different temperatures had very little effect on the <span class="hlt">mechanism</span> of <span class="hlt">deformation</span>, though differences were seen in the bulk properties. Furthermore, hydration had little effect on the crystalline materials, though degradation over 8 months resulted in loss of <span class="hlt">mechanical</span> properties for samples produced at higher annealing temperatures. In conclusion, the introduction of crystallinity had a huge effect on both bulk and microscopic properties of PLLA, but the spherulitic structure of the crystalline material affected the bulk properties significantly more than it did the micromechanism of <span class="hlt">deformation</span>. PMID:15949544</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.2507K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.2507K"><span id="translatedtitle">Identifying <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in the NEEM ice core using EBSD measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuiper, Ernst-Jan; Weikusat, Ilka; Drury, Martyn R.; Pennock, Gill M.; de Winter, Matthijs D. A.</p> <p>2015-04-01</p> <p><span class="hlt">Deformation</span> of ice in continental sized ice sheets determines the flow behavior of ice towards the sea. Basal dislocation glide is assumed to be the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in the creep <span class="hlt">deformation</span> of natural ice, but non-basal glide is <span class="hlt">active</span> as well. Knowledge of what types of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are <span class="hlt">active</span> in polar ice is critical in predicting the response of ice sheets in future warmer climates and its contribution to sea level rise, because the <span class="hlt">activity</span> of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> depends critically on <span class="hlt">deformation</span> conditions (such as temperature) as well as on the material properties (such as grain size). One of the methods to study the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in natural materials is Electron Backscattered Diffraction (EBSD). We obtained ca. 50 EBSD maps of five different depths from a Greenlandic ice core (NEEM). The step size varied between 8 and 25 micron depending on the size of the <span class="hlt">deformation</span> features. The size of the maps varied from 2000 to 10000 grid point. Indexing rates were up to 95%, partially by saving and reanalyzing the EBSP patterns. With this method we can characterize subgrain boundaries and determine the lattice rotation configurations of each individual subgrain. Combining these observations with arrangement/geometry of subgrain boundaries the dislocation types can be determined, which form these boundaries. Three main types of subgrain boundaries have been recognized in Antarctic (EDML) ice core¹². Here, we present the first results obtained from EBSD measurements performed on the NEEM ice core samples from the last glacial period, focusing on the relevance of dislocation <span class="hlt">activity</span> of the possible slip systems. Preliminary results show that all three subgrain types, recognized in the EDML core, occur in the NEEM samples. In addition to the classical boundaries made up of basal dislocations, subgrain boundaries made of non-basal dislocations are also common. ¹Weikusat, I.; de Winter, D. A. M.; Pennock, G. M.; Hayles, M</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21362167','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21362167"><span id="translatedtitle">A <span class="hlt">deformation</span> quantization theory for noncommutative quantum <span class="hlt">mechanics</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Costa Dias, Nuno; Prata, Joao Nuno; Gosson, Maurice de; Luef, Franz</p> <p>2010-07-15</p> <p>We show that the <span class="hlt">deformation</span> quantization of noncommutative quantum <span class="hlt">mechanics</span> previously considered by Dias and Prata ['Weyl-Wigner formulation of noncommutative quantum <span class="hlt">mechanics</span>', J. Math. Phys. 49, 072101 (2008)] and Bastos, Dias, and Prata ['Wigner measures in non-commutative quantum <span class="hlt">mechanics</span>', e-print arXiv:math-ph/0907.4438v1; Commun. Math. Phys. (to appear)] can be expressed as a Weyl calculus on a double phase space. We study the properties of the star-product thus defined and prove a spectral theorem for the star-genvalue equation using an extension of the methods recently initiated by de Gosson and Luef ['A new approach to the *-genvalue equation', Lett. Math. Phys. 85, 173-183 (2008)].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998APS..MAR.U3834H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1998APS..MAR.U3834H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> and Fracture <span class="hlt">Mechanisms</span> of Polymer-Silicate Nanocomposites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harcup, Jason; Yee, Albert</p> <p>1998-03-01</p> <p>The <span class="hlt">deformation</span> and fracture behavior of a series of nanocomposites comprising polyamide, silicate and in some cases rubber has been studied. <span class="hlt">Mechanical</span> properties including Young modulus and fracture toughness were measured and it was found that compared to conventional composites, the nanocomposites exhibited far greater improvement in properties over the neat matrix for a given silicate fraction. It was also found that the addition of the rubber phase produced an increase in toughness. The arrested crack tip process zone was obtained using the Double Notch Four Point Bend test geometry and the process zone morphology was studied using TEM and TOM. Fracture surfaces were probed with XEDS and SEM. The use of these techniques enabled the <span class="hlt">mechanisms</span> which occur during fracture to be studied and related to the <span class="hlt">mechanical</span> properties and toughening of these materials.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/83356','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/83356"><span id="translatedtitle">Rheology and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of an isotropic mica schist</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shea, W.T.; Kronenberg, A.K.</p> <p>1992-10-10</p> <p>The authors have investigated the transitional, semibrittle <span class="hlt">deformation</span> of a mica schist ({approximately} 75% biotite) by shortening cylinders cored at 0{degrees}, 45{degrees}, and 90{degrees} to foliation to varying strains, at confining pressures P{sub c} to 500 MPa, constant strain rates {epsilon} from 1.5 x 10{sup {minus}7} to 1.6 x 10{sup {minus}4} s{sup {minus}1}, and temperatures T from 25{degrees} to 400{degrees}C. <span class="hlt">Deformation</span> is concentrated within one or more throughgoing, millimeter-wide shear zones at all conditions; these localize at low strains ({epsilon} < 2%) through the nucleation and coalescence of dense sets of intragranular microkink bands (MKBs). Despite distinct differences in the relative number of mica grains oriented favorably for slip and kinking in different loading directions, the differential stresses required for shear zone development vary little with fabric orientation. Biotite schist undergoes a transition from strain-softening to steady strength <span class="hlt">mechanical</span> response at confining pressures in the range 75 to 150 MPa. The pressure sensitivity of strength (characterized by the slope {mu} of the Mohr envelope) decreases from {mu} {approximately} 0.5 (at P{sub c} < 100 MPa) to {mu} < 0.1 at pressures greater than 200 MPa, reflecting the increasing contribution of glide and kinking in biotite at higher pressures. However, dilatancy associated with microcracking and void formation along MKB boundaries persists to at least 500 MPa. Application of the results to crustal <span class="hlt">deformation</span> suggests that mica-rich aggregates are weaker than other common rock types throughout a broad midcrustal depth range, supporting the inference that retrograde reaction to phyllosilicates may be important in localizing crustal <span class="hlt">deformations</span> within large faults and shear zones. 111 refs., 24 figs., 4 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.T51A4582F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.T51A4582F"><span id="translatedtitle"><span class="hlt">Deformation</span>-induced diagenesis and microbial <span class="hlt">activity</span> in the Nankai accretionary prism</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Famin, V.; Andreani, M.; Boullier, A. M.; Raimbourg, H.; Magnin, V.</p> <p>2014-12-01</p> <p>We performed a microscopic and chemical study of diagenetic reactions in <span class="hlt">deformation</span> microstructures within deep mud sediments from the Nankai accretionary prism (SW Japan) collected during IODP Expedition 315. Our study reveals that <span class="hlt">deformation</span> microstructures localize the crystallization of pyrite, a diagenetic reaction also found in large megasplay faults of the prism. Textural observation shows that pyrite crystallization is synchronous of the sediment <span class="hlt">deformation</span>. The framboidal shape of pyrite crystals, the barium depletion and the strong arsenic enrichment observed in <span class="hlt">deformation</span> microstructures compared with the sediment matrix, suggest that pyrite crystallization is mediated by the proliferation of anoxic archae. During scientific drilling expeditions IODP 315, 316 and 319, microbial life has been evidenced at depths of up to 800 m below the sea floor by the presence of biogenic methane and sulfate reducers in sediments. We suggest that <span class="hlt">deformation</span> structures localize microbial proliferation because the fracturing of silicate minerals produces hydrogen, a necessary compound for bacteria under anoxic conditions. Bacteria proliferate as long as <span class="hlt">active</span> <span class="hlt">deformation</span> supplies hydrogen, and vanish when the <span class="hlt">deformation</span> stops. The development of bacteria in <span class="hlt">deformation</span> structures impacts our <span class="hlt">mechanical</span> understanding of fault zones in accretionary prisms: Firstly, bacterial <span class="hlt">activity</span> converts carbon from organic matter and hydrogen into methane and/or water, which may alter the fluid budget of fault zones and the recurrence of dynamic ruptures in megathrusts. Secondly, the abundance of bacteria could be used to recognize <span class="hlt">active</span> fault zones from inactive ones in drilling cores.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1001009','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1001009"><span id="translatedtitle">In situ TEM straining of nanograined free-standing thin films reveals various unexpected <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Follstaedt, David Martin; Knapp, James Arthur; Clark, Blythe G.; Hattar, Khalid M.; Robertson, Ian M.</p> <p>2010-04-01</p> <p>In-situ transmission electron microscopy (TEM) straining experiments provide direct detailed observation of the <span class="hlt">deformation</span> and failure <span class="hlt">mechanisms</span> <span class="hlt">active</span> at a length scale relevant to nanomaterials. This presentation will detail continued investigations into the <span class="hlt">active</span> <span class="hlt">mechanisms</span> governing high purity nanograined pulsed-laser deposited (PLD) nickel, as well as recent work into dislocation-particle interactions in nanostructured PLD aluminum-alumina alloys. Straining experiments performed on nanograined PLD free-standing nanograined Ni films with an engineered grain size distribution revealed that the addition of ductility with limited decrease in strength, reported in such metals, can be attributed to the simultaneous <span class="hlt">activity</span> of three <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in front of the crack tip. At the crack tip, a grain agglomeration <span class="hlt">mechanism</span> occurs where several nanograins appear to rotate, resulting in a very thin, larger grain immediately prior to failure. In the classical plastic zone in front of the crack tip, a multitude of <span class="hlt">mechanisms</span> were found to operate in the larger grains including: dislocation pile-up, twinning, and stress-assisted grain growth. The region outside of the plastic zone showed signs of elasticity with limited indications of dislocation <span class="hlt">activity</span>. The insight gained from in-situ TEM straining experiments of nanograined PLD Ni provides feedback for models of the <span class="hlt">deformation</span> and failure in nanograined FCC metals, and suggests a greater complexity in the <span class="hlt">active</span> <span class="hlt">mechanisms</span>. The investigation into the <span class="hlt">deformation</span> and failure <span class="hlt">mechanisms</span> of FCC metals via in-situ TEM straining experiments has been expanded to the effect of hard particles on the <span class="hlt">active</span> <span class="hlt">mechanisms</span> in nanograined aluminum with alumina particles. The microstructures investigated were developed with varying composition, grain size, and particle distribution via tailoring of the PLD conditions and subsequent annealing. In order to develop microstructures suitable for in-situ <span class="hlt">deformation</span> testing</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012SPIE.8252E..0NK&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012SPIE.8252E..0NK&link_type=ABSTRACT"><span id="translatedtitle">Miniature non-<span class="hlt">mechanical</span> zoom camera using <span class="hlt">deformable</span> MOEMS mirrors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaylor, Brant M.; Wilson, Christopher R.; Greenfield, Nathan J.; Roos, Peter A.; Seger, Eric M.; Moghimi, Mohammad J.; Dickensheets, David L.</p> <p>2012-03-01</p> <p>We present a miniature non-<span class="hlt">mechanical</span> zoom camera using <span class="hlt">deformable</span> MOEMS mirrors. Bridger Photonics, Inc. (Bridger) in collaboration with Montana State University (MSU), has developed electrostatically actuated <span class="hlt">deformable</span> MEMS mirrors for use in compact focus control and zoom imaging systems. Applications including microscopy, endomicroscopy, robotic surgery and cell-phone cameras. In comparison to conventional systems, our MEMS-based designs require no <span class="hlt">mechanically</span> moving parts. Both circular and elliptical membranes are now being manufactured at the wafer level and possess excellent optical surface quality (membrane flatness < λ/4). The mirror diameters range from 1 - 4 mm. For membranes with a 25 μm air gap, the membrane stroke is 10 μm. In terms of the optical design, the mirrors are considered variable power optical elements. A device with 2 mm diameter and 10 μm stroke can vary its optical power over 40 diopters or 0.04mm∧(-1). Equivalently, this corresponds to a focal length ranging from infinity to 25 mm. We have designed and demonstrated a zoom system using two MOEMS elements and exclusively commercial off-the-shelf optical components to achieve an optical zoom of 1.9x with a 15° full field of view. The total optical track length of the system is 36 mm. The design is approximately 30 mm x 30 mm x 20 mm including the optomechanical housing and image sensor. With custom optics, we anticipate achieving form factors that are compatible with incorporation into cell phones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22412962','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22412962"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of Cu nanowires with planar defects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tian, Xia Yang, Haixia; Wan, Rui; Cui, Junzhi; Yu, Xingang</p> <p>2015-01-21</p> <p>Molecular dynamics simulations are used to investigate the <span class="hlt">mechanical</span> behavior of Cu nanowires (NWs) with planar defects such as grain boundaries (GBs), twin boundaries (TBs), stacking faults (SFs), etc. To investigate how the planar defects affect the <span class="hlt">deformation</span> and fracture <span class="hlt">mechanisms</span> of naowires, three types of nanowires are considered in this paper: (1) polycrystalline Cu nanowire; (2) single-crystalline Cu nanowire with twin boundaries; and (3) single-crystalline Cu nanowire with stacking faults. Because of the large fraction of atoms at grain boundaries, the energy of grain boundaries is higher than that of the grains. Thus, grain boundaries are proved to be the preferred sites for dislocations to nucleate. Moreover, necking and fracture prefer to occur at the grain boundary interface owing to the weakness of grain boundaries. For Cu nanowires in the presence of twin boundaries, it is found that twin boundaries can strength nanowires due to the restriction of the movement of dislocations. The pile up of dislocations on twin boundaries makes them rough, inducing high energy in twin boundaries. Hence, twin boundaries can emit dislocations, and necking initiates at twin boundaries. In the case of Cu nanowires with stacking faults, all pre-existing stacking faults in the nanowires are observed to disappear during <span class="hlt">deformation</span>, giving rise to a fracture process resembling the samples without stacking fault.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9677E..0WD','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9677E..0WD"><span id="translatedtitle">Distributed <span class="hlt">deformation</span> measurement of large space deployable <span class="hlt">mechanism</span> based on FBG sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dong, Yanfang; Zhou, Zude; Liu, Yi; Liu, Mingyao; Li, Ruiya; Li, Tianliang</p> <p>2015-10-01</p> <p>Space deployable <span class="hlt">mechanisms</span> are widely used, important and multi-purpose components in aerospace fields. In order to ensure the <span class="hlt">mechanism</span> in normal situation after unfolded, detecting the <span class="hlt">deformation</span> caused by huge temperature difference in real-time is necessary. This paper designed a deployable <span class="hlt">mechanism</span> setup, completed its distributed <span class="hlt">deformation</span> measurement by means of fiber Bragg grating (FBG) sensors and BP neural network, proved the <span class="hlt">mechanism</span> distributed strain takes place sequence and FBG sensor is capable for space deployable <span class="hlt">mechanisms</span> <span class="hlt">deformation</span> measuring.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MS%26E...62a2028W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MS%26E...62a2028W"><span id="translatedtitle">Tensile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of ABS/PMMA/EMA blends</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, S. H.; Gao, J.; Lin, S. X.; Zhang, P.; Huang, J.; Xu, L. L.</p> <p>2014-08-01</p> <p>The tensile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of acrylonitrile - butadiene - styrene (ABS) / polymethyl methacrylate (PMMA) blends toughened by ethylene methacrylate (EMA) copolymer was investigated by analysing the fracture morphology. ABS/PMMA was blended with EMA copolymer by melt mixing technique using co-rotating twin extruder. Tensile tests show that the elongation at break of ABS/PMMA blends can be efficiently improved with the increase in EMA content. Fracture morphology of ABS/PMMA/EMA blends reveals that the material yield induced by hollowing-out of EMA particles and its propagation into yield zone is the main toughening <span class="hlt">mechanism</span>. Moreover, the appearance that EMA particles in the central area are given priority to hollowing-out may be related to the skin-core structure of the injection moulded parts caused by the different cooling rate between surface and inside in the process of injection moulding.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......120K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......120K"><span id="translatedtitle">EBSD characterization of low temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in modern alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kozmel, Thomas S., II</p> <p></p> <p>For structural applications, grain refinement has been shown to enhance <span class="hlt">mechanical</span> properties such as strength, fatigue resistance, and fracture toughness. Through control of the thermos-<span class="hlt">mechanical</span> processing parameters, dynamic recrystallization <span class="hlt">mechanisms</span> were used to produce microstructures consisting of sub-micron grains in 9310 steel, 4140 steel, and Ti-6Al-4V. In both 9310 and 4140 steel, the distribution of carbides throughout the microstructure affected the ability of the material to dynamically recrystallize and determined the size of the dynamically recrystallized grains. Processing the materials at lower temperatures and higher strain rates resulted in finer dynamically recrystallized grains. Microstructural process models that can be used to estimate the resulting microstructure based on the processing parameters were developed for both 9310 and 4140 steel. Heat treatment studies performed on 9310 steel showed that the sub-micron grain size obtained during <span class="hlt">deformation</span> could not be retained due to the low equilibrium volume fraction of carbides. Commercially available aluminum alloys were investigated to explain their high strain rate <span class="hlt">deformation</span> behavior. Alloys such as 2139, 2519, 5083, and 7039 exhibit strain softening after an ultimate strength is reached, followed by a rapid degradation of <span class="hlt">mechanical</span> properties after a critical strain level has been reached. Microstructural analysis showed that the formation of shear bands typically preceded this rapid degradation in properties. Shear band boundary misorientations increased as a function of equivalent strain in all cases. Precipitation behavior was found to greatly influence the microstructural response of the alloys. Additionally, precipitation strengthened alloys were found to exhibit similar flow stress behavior, whereas solid solution strengthened alloys exhibited lower flow stresses but higher ductility during dynamic loading. Schmid factor maps demonstrated that shear band formation behavior</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17112531','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17112531"><span id="translatedtitle"><span class="hlt">Mechanics</span> and <span class="hlt">deformation</span> of the nucleus in micropipette aspiration experiment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vaziri, Ashkan; Mofrad, Mohammad R Kaazempur</p> <p>2007-01-01</p> <p>Robust biomechanical models are essential for the study of nuclear <span class="hlt">mechanics</span> and <span class="hlt">deformation</span> and can help shed light on the underlying <span class="hlt">mechanisms</span> of stress transition in nuclear elements. Here, we develop a computational model for an isolated nucleus undergoing micropipette aspiration. Our model includes distinct components representing the nucleoplasm and nuclear envelope. The nuclear envelope itself comprises three layers: inner and outer nuclear membranes and one thicker layer representing the nuclear lamina. The nucleoplasm is modeled as a viscoelastic Maxwell material with a single time constant, while a modified Maxwell model, equivalent to a spring and a dashpot in series and both in parallel with a spring, is adopted for the inner and outer nuclear membranes. The nuclear envelope layer is taken as a linear elastic material. The proposed computational model, validated using experimental observations of Guilak et al. [2000. Viscoelastic properties of the cell nucleus. Biochemical and Biophysical Research Communications 269, 781-786] and Deguchi et al. [2005, Flow-induced hardening of endothelial nucleus as an intracellular stress-bearing organelle. Journal of Biomechanics 38, 1751-1759], is employed to study nuclear <span class="hlt">mechanics</span> and <span class="hlt">deformation</span> in micropipette aspiration and to shed light on the contribution of individual nuclear components on the response. The results indicate that the overall response of an isolated nucleus in micropipette aspiration is highly sensitive to the apparent stiffness of the nuclear lamina. This observation suggests that micropipette aspiration is an effective technique for examining the influence of various kinds of alteration in the nuclear lamina, such as mutations in the gene encoding lamin A, and also structural remodeling due to <span class="hlt">mechanical</span> perturbation. PMID:17112531</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MS%26E...63a2125N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MS%26E...63a2125N"><span id="translatedtitle">Effect of dislocation and grain boundary on <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in ultrafine-grained interstitial-free steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakazawa, K.; Itoh, S.; Matsunaga, T.; Matsukawa, Y.; Satoh, Y.; Murase, Y.; Abe, H.</p> <p>2014-08-01</p> <p>Ultrafine-grained interstitial-free steel fabricated by the accumulative roll-bonding method was subjected to tensile tests and analyses of AFM, TEM and XRD to identify the effects of interaction between dislocations and grain boundaries (GB) on the <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. The AFM analyses indicated that the main <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of this material changed from dislocation motion to grain boundary sliding (GBS) with decreasing strain rate. TEM observations and XRD analysis revealed showed that dislocations piled up at GB and the dislocation density decreased with increasing strain. Those suggest the dislocations are absorbed into GB during <span class="hlt">deformation</span>, <span class="hlt">activating</span> slip-induced GBS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1073049','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1073049"><span id="translatedtitle">STATISTICAL <span class="hlt">MECHANICS</span> MODELING OF MESOSCALE <span class="hlt">DEFORMATION</span> IN METALS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Anter El-Azab</p> <p>2013-04-08</p> <p>The research under this project focused on a theoretical and computational modeling of dislocation dynamics of mesoscale <span class="hlt">deformation</span> of metal single crystals. Specifically, the work aimed to implement a continuum statistical theory of dislocations to understand strain hardening and cell structure formation under monotonic loading. These aspects of crystal <span class="hlt">deformation</span> are manifestations of the evolution of the underlying dislocation system under <span class="hlt">mechanical</span> loading. The project had three research tasks: 1) Investigating the statistical characteristics of dislocation systems in <span class="hlt">deformed</span> crystals. 2) Formulating kinetic equations of dislocations and coupling these kinetics equations and crystal <span class="hlt">mechanics</span>. 3) Computational solution of coupled crystal <span class="hlt">mechanics</span> and dislocation kinetics. Comparison of dislocation dynamics predictions with experimental results in the area of statistical properties of dislocations and their field was also a part of the proposed effort. In the first research task, the dislocation dynamics simulation method was used to investigate the spatial, orientation, velocity, and temporal statistics of dynamical dislocation systems, and on the use of the results from this investigation to complete the kinetic description of dislocations. The second task focused on completing the formulation of a kinetic theory of dislocations that respects the discrete nature of crystallographic slip and the physics of dislocation motion and dislocation interaction in the crystal. Part of this effort also targeted the theoretical basis for establishing the connection between discrete and continuum representation of dislocations and the analysis of discrete dislocation simulation results within the continuum framework. This part of the research enables the enrichment of the kinetic description with information representing the discrete dislocation systems behavior. The third task focused on the development of physics-inspired numerical methods of solution of the coupled</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930006641','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930006641"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of NiAl cyclicly <span class="hlt">deformed</span> near the brittle-to-ductile transformation temperature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antolovich, Stephen D.; Saxena, Ashok; Cullers, Cheryl</p> <p>1992-01-01</p> <p>One of the ongoing challenges of the aerospace industry is to develop more efficient turbine engines. Greater efficiency entails reduced specific strength and larger temperature gradients, the latter of which means higher operating temperatures and increased thermal conductivity. Continued development of nickel-based superalloys has provided steady increases in engine efficiency and the limits of superalloys have probably not been realized. However, other material systems are under intense investigation for possible use in high temperature engines. Ceramic, intermetallic, and various composite systems are being explored in an effort to exploit the much higher melting temperatures of these systems. NiAl is considered a potential alternative to conventional superalloys due to its excellent oxidation resistance, low density, and high melting temperature. The fact that NiAl is the most common coating for current superalloy turbine blades is a tribute to its oxidation resistance. Its density is one-third that of typical superalloys and in most temperature ranges its thermal conductivity is twice that of common superalloys. Despite these many advantages, NiAl requires more investigation before it is ready to be used in engines. Binary NiAl in general has poor high-temperature strength and low-temperature ductility. On-going research in alloy design continues to make improvements in the high-temperature strength of NiAl. The factors controlling low temperature ductility have been identified in the last few years. Small, but reproducible ductility can now be achieved at room temperature through careful control of chemical purity and processing. But the <span class="hlt">mechanisms</span> controlling the transition from brittle to ductile behavior are not fully understood. Research in the area of fatigue <span class="hlt">deformation</span> can aid the development of the NiAl system in two ways. Fatigue properties must be documented and optimized before NiAl can be applied to engineering systems. More importantly though</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008SPIE.7018E..33Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SPIE.7018E..33Y"><span id="translatedtitle">New design <span class="hlt">deforming</span> controlling system of the <span class="hlt">active</span> stressed lap</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ying, Li; Wang, Daxing</p> <p>2008-07-01</p> <p>A 450mm diameter <span class="hlt">active</span> stressed lap has been developed in NIAOT by 2003. We design a new lap in 2007. This paper puts on emphases on introducing the new <span class="hlt">deforming</span> control system of the lap. Aiming at the control characteristic of the lap, a new kind of digital <span class="hlt">deforming</span> controller is designed. The controller consists of 3 parts: computer signal disposing, motor driving and force sensor signal disposing. Intelligent numeral PID method is applied in the controller instead of traditional PID. In the end, the result of new <span class="hlt">deformation</span> are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..MARJ21002R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..MARJ21002R"><span id="translatedtitle">Molecular <span class="hlt">mechanisms</span> of <span class="hlt">deformation</span> and failure in glassy materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rottler, Joerg</p> <p>2004-03-01</p> <p>Understanding the molecular origins of macroscopic <span class="hlt">mechanical</span> properties is a fundamental scientific challenge. Fracture of both amorphous and crystalline materials involves many length scales reaching from the continuum to atomic level processes near a crack tip. Using molecular simulations of simple models for amorphous glassy materials, we first study elastoplastic <span class="hlt">deformation</span> and discuss the nature of the shear yield stress and its dependence on loading conditions, strain rate and temperature. We then focus on the <span class="hlt">deformation</span> of glassy polymeric systems into crazes at large strains. In the craze, polymers ( 0.5 nm diameter) are bundled into an intricate network of 10 nm diameter fibrils that extends 10 micrometers on either side of a mm crack tip. Analysis of local geometry and stresses provide insight into the real-space nature of the entanglements that control craze formation as well as melt dynamics. Crazes are also shown to share many features with jammed systems such as granular media and foams, but are unique in jamming under a tensile load. This allows explanations for the exponential force distribution in jammed systems to be tested. The force distribution strongly influences the ultimate breakdown of the craze fibrils either through disentanglement or chain scission. We conclude by quantifying the contribution of crazing to the unusually large fracture energy of glassy polymers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..1212506C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..1212506C"><span id="translatedtitle"><span class="hlt">Active</span> compressive intraoceanic <span class="hlt">deformation</span>: early stages of ophiolites emplacement?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chamot-Rooke, Nicolas; Delescluse, Matthias; Montési, Laurent</p> <p>2010-05-01</p> <p>Oceanic lithosphere is strong and continental lithosphere is weak. As a result, there is relatively little <span class="hlt">deformation</span> in the oceanic domain away from plate boundaries. However, the interior of oceanic lithosphere does <span class="hlt">deform</span> when highly stressed. We review here places where intraoceanic compression is at work. In the more than 30 years since the first observations of <span class="hlt">active</span> compressive intraplate <span class="hlt">deformation</span> in the Central Indian Ocean through seismic profiling (Eittreim et al., 1972), compressive <span class="hlt">deformation</span> has been identified in a variety of other oceanic tectonic settings: as a result of small differential motion between large plates (between North America and South America in the Central Atlantic; between Eurasia and Nubia offshore Gibraltar; between Macquarie and Australia plates in the Southern Ocean), within back-arcs (northwest Celebes Sea, Okushiri Ridge in the Japan Sea, on the eastern border of the Caroline plate), and ahead of subduction (Zenisu Ridge off Nankai Trough). <span class="hlt">Deformation</span> appears to be more diffuse when larger plates are involved, and more localized for younger plates, perhaps in relation with the increasing rigidity of oceanic plates with age. The best example of diffuse <span class="hlt">deformation</span> studied so far remains the Central Indian Ocean. Numerous marine data have been collected in this area, including shallow and deep seismic, heat flow measurements, multibeam bathymetry. The present-day <span class="hlt">deformation</span> field has been modeled using GPS and earthquakes as far field and near field constraints respectively. Reactivation of the oceanic fabric (including for portions of the Indo-Australian plate which are now in subduction as evidenced by the September 2009 Padang earthquake), selective fault abandonment (Delescluse et al., 2008) and serpentinization (Delescluse and Chamot-Rooke, 2008) are some of the important processes that shape the present-day pattern of <span class="hlt">deformation</span>. These rare intraplate <span class="hlt">deformation</span> areas constitute excellent natural laboratories to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA....10157S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA....10157S"><span id="translatedtitle">Cenozoic to <span class="hlt">active</span> <span class="hlt">deformation</span> in Western Yunnan (Myanmar China border)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Socquet, A.; Pubellier, M.</p> <p>2003-04-01</p> <p> accepted that all of this motion is accommodated onto a single fault: the Sagaing fault in Myanmar. However, geodetic results show that, out of the 35 mm/yr of India versus Sundaland rate, only 18 mm / yr are accommodated by the Sagaing fault. Part of the remaining motion might be accommodated in western Yunnan. The present system might have been <span class="hlt">active</span> since the Pliocene. We regard it as a combination of the right-lateral Sagaing Fault / Gaoligong, which propagates toward the north as a horsetail, and the circum syntaxis fault system. The state of stress, in Western Yunnan, is a WNW extension inferred from both focal <span class="hlt">mechanisms</span> and recent fault-slip data analysis. The tectonic features are influenced by both the clockwise flow around the Eastern Himalayan Syntaxis, and the northern extension along splays of the Sagaing fault. <span class="hlt">Deformation</span> is then distributed between strike-slip and normal faulting. We propose that this interaction is accommodated by clockwise rotations of blocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JAP...104e3505J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JAP...104e3505J"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> transition caused by strain rate in a pulse electric brush-plated nanocrystalline Cu</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiang, Zhonghao; Zhang, Hanzhuo; Gu, Changdong; Jiang, Qing; Lian, Jianshe</p> <p>2008-09-01</p> <p>Bulk nanocrystalline Cu was synthesized by a pulse electric brush-plating technique. A very large strength (at 2% plastic strain) increase from 644 to 1451 MPa was obtained by compression tests at room temperature and strain rates from 1×10-5 to 3×100 s-1. A transition in plastic <span class="hlt">deformation</span> <span class="hlt">mechanism</span> with strain rate from a combination of the thermally <span class="hlt">activated</span> grain boundary sliding and the dislocation emission-absorption in grain boundaries to one dominated by the dislocation <span class="hlt">activity</span> has been revealed by the significant changes in strain rate sensitivity and apparent <span class="hlt">activation</span> volume with strain rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......345K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......345K"><span id="translatedtitle">Atomistic simulations of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in ultralight weight Mg-Li alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karewar, Shivraj</p> <p></p> <p>Mg alloys have spurred a renewed academic and industrial interest because of their ultra-light-weight and high specific strength properties. Hexagonal close packed Mg has low <span class="hlt">deformability</span> and a high plastic anisotropy between basal and non-basal slip systems at room temperature. Alloying with Li and other elements is believed to counter this deficiency by <span class="hlt">activating</span> non-basal slip by reducing their nucleation stress. In this work I study how Li addition affects <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in Mg using atomistic simulations. In the first part, I create a reliable and transferable concentration dependent embedded atom method (CD-EAM) potential for my molecular dynamics study of <span class="hlt">deformation</span>. This potential describes the Mg-Li phase diagram, which accurately describes the phase stability as a function of Li concentration and temperature. Also, it reproduces the heat of mixing, lattice parameters, and bulk moduli of the alloy as a function of Li concentration. Most importantly, our CD-EAM potential reproduces the variation of stacking fault energy for basal, prismatic, and pyramidal slip systems that in uences the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> as a function of Li concentration. This success of CD-EAM Mg-Li potential in reproducing different properties, as compared to literature data, shows its reliability and transferability. Next, I use this newly created potential to study the effect of Li addition on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in Mg-Li nanocrystalline (NC) alloys. Mg-Li NC alloys show basal slip, pyramidal type-I slip, tension twinning, and two-compression twinning <span class="hlt">deformation</span> modes. Li addition reduces the plastic anisotropy between basal and non-basal slip systems by modifying the energetics of Mg-Li alloys. This causes the solid solution softening. The inverse relationship between strength and ductility therefore suggests a concomitant increase in alloy ductility. A comparison of the NC results with single crystal <span class="hlt">deformation</span> results helps to understand the qualitative and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004MMTA...35..797P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004MMTA...35..797P"><span id="translatedtitle"><span class="hlt">Deformation</span> and damage <span class="hlt">mechanisms</span> of zinc coatings on hot-dip galvanized steel sheets: Part I. <span class="hlt">Deformation</span> modes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parisot, Rodolphe; Forest, Samuel; Pineau, André; Grillon, François; Demonet, Xavier; Mataigne, Jean-Michel</p> <p>2004-03-01</p> <p>Zinc-based coatings are widely used for protection against corrosion of steel-sheet products in the automotive industry. The objective of the present article is to investigate the <span class="hlt">deformation</span> modes at work in three different microstructures of a thin (8 µm) zinc coating on an interstitial-free steel substrate under tension, plane-strain tension, and expansion loading. Damage <span class="hlt">mechanisms</span> are addressed in a companion article. The plastic slip and twinning <span class="hlt">activity</span> in the zinc grains of an untempered cold-rolled coating (labeled NSK), a tempered cold-rolled coating (labeled SK), and a recrystallized coating are compared with the response of the corresponding bulk low-alloyed zinc material. The in-plane grain size in the NSK and SK coatings ranges from 300 to 600 µm, vs about 30 µm in the recrystallized coating and bulk material. The coatings exhibit a strong crystallographic texture, with the c-axis generally normal to the sheet plane. Basal slip is shown to be the main <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in bulk zinc and the recrystallized coating, whereas pyramidal π2 slip and <span class="hlt">mechanical</span> twinning are found to be major modes in the NSK and SK coatings. These results, obtained from an extensive, quantitative slip-line analysis combined with electron backscattered diffraction (EBSD) measurements, are explained by the constraining effect of the substrate. This effect is successfully modeled using a simple Taylor-like polycrystalline approach. The recrystallized coating behaves much like the bulk material. The interpretation of this grain-size effect between the NSK and SK coating, on the one hand, and the recrystallized coating, on the other hand, requires a full three-dimensional finite-element analysis of the multicrystalline coating provided in this work. The simulations show that strong strain gradients can develop in the recrystallized coating from the interface to the surface, which is not the case in the NSK and SK coatings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMMR51A..04P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMMR51A..04P"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of antigorite and strain localization during dehydration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Proctor, B.; Hirth, G.</p> <p>2012-12-01</p> <p>Antigorite, the high temperature and pressure serpentine polytype, is thought to exist along subduction zones between the mantle wedge and the subducting oceanic crust (e.g., Wada et al., 2008). Understanding how the rheology of antigorite changes with depth along the slab may be key to understanding seismicity along the upper plate boundary (e.g., Hacker et al., 2003). To explore this phenomenon we are conducting constant strain rate general shear experiments on antigorite-rich serpentinite at shear strain rates of 5*10^-7/s to 10^-5/s, confining pressures from 1-2 GPa and temperatures from 400-700°C. We are using microstructural observations to constrain <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and investigate conditions where strain localization occurs. In some experiments we employ either strain rate stepping or temperature ramping to examine the stress dependence of viscosity (i.e., determine stress exponent) and syntectonic reaction during heating. The results of our general shear experiments suggest the rheologic behavior of antigorite varies significantly with changes in temperature and pressure, similar to previous work in axial compression (e.g., Chernak and Hirth, 2010). At 400°C and 1GPa confining pressure antigorite <span class="hlt">deforms</span> initially via steady-state ductile flow with strengths as high as 1.4 GPa at a strain rate of 10^-5/s. With increasing strain we observe weakening events that correlate with the development of shear fractures within the sample. At 2GPa pressure, the flow strength of antigorite increases to ~1.8 GPa at 10^-6/s and <span class="hlt">deformation</span> is distributed at low strain. Strain rate stepping at these conditions suggests a very weak strain rate dependence on strength with a 5-10% change in stress for an order of magnitude strain rate step. At 700C and 1 GPa, above the thermal stability of antigorite, the steady-state strength is ~120 MPa at 10^-5/s. In these samples olivine becomes the dominant phase as antigorite progressively reacts to olivine and pyroxene. At the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18157134','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18157134"><span id="translatedtitle"><span class="hlt">Mechanical</span> annealing and source-limited <span class="hlt">deformation</span> in submicrometre-diameter Ni crystals.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Shan, Z W; Mishra, Raja K; Syed Asif, S A; Warren, Oden L; Minor, Andrew M</p> <p>2008-02-01</p> <p>The fundamental processes that govern plasticity and determine strength in crystalline materials at small length scales have been studied for over fifty years. Recent studies of single-crystal metallic pillars with diameters of a few tens of micrometres or less have clearly demonstrated that the strengths of these pillars increase as their diameters decrease, leading to attempts to augment existing ideas about pronounced size effects with new models and simulations. Through in situ nanocompression experiments inside a transmission electron microscope we can directly observe the <span class="hlt">deformation</span> of these pillar structures and correlate the measured stress values with discrete plastic events. Our experiments show that submicrometre nickel crystals microfabricated into pillar structures contain a high density of initial defects after processing but can be made dislocation free by applying purely <span class="hlt">mechanical</span> stress. This phenomenon, termed '<span class="hlt">mechanical</span> annealing', leads to clear evidence of source-limited <span class="hlt">deformation</span> where atypical hardening occurs through the progressive <span class="hlt">activation</span> and exhaustion of dislocation sources. PMID:18157134</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1253605','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1253605"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> study of a hot rolled Zr-2.5Nb alloy by transmission electron microscopy. II. In situ transmission electron microscopy study of <span class="hlt">deformation</span> <span class="hlt">mechanism</span> change of a Zr-2.5Nb alloy upon heavy ion irradiation.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Long, Fei; Daymond, Mark R.; Yao, Zhongwen; Kirk, Marquis A.</p> <p>2015-03-14</p> <p>The effect of heavy-ion irradiation on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a Zr-2.5Nb alloy was investigated by using the in situ transmission electron microscopy <span class="hlt">deformation</span> technique. The gliding behavior of prismatic < a > dislocations has been dynamically observed before and after irradiation at room temperature and 300 degrees C. Irradiation induced loops were shown to strongly pin the gliding dislocations. Unpinning occurred while loops were incorporated into or eliminated by < a > dislocations. In the irradiated sample, loop depleted areas with a boundary parallel to the basal plane trace were found by post-mortem observation after room temperature <span class="hlt">deformation</span>, supporting the possibility of basal channel formation in bulk neutron irradiated samples. Strong <span class="hlt">activity</span> of pyramidal slip was also observed at both temperatures, which might be another important <span class="hlt">mechanism</span> to induce plastic instability in irradiated zirconium alloys. Finally, {01 (1) over bar1}< 0 (1) over bar 12 > twinning was identified in the irradiated sample <span class="hlt">deformed</span> at 300 degrees C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1179294','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1179294"><span id="translatedtitle"><span class="hlt">Deformation</span> and Failure <span class="hlt">Mechanisms</span> of Shape Memory Alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Daly, Samantha Hayes</p> <p>2015-04-15</p> <p>The goal of this research was to understand the fundamental <span class="hlt">mechanics</span> that drive the <span class="hlt">deformation</span> and failure of shape memory alloys (SMAs). SMAs are difficult materials to characterize because of the complex phase transformations that give rise to their unique properties, including shape memory and superelasticity. These phase transformations occur across multiple length scales (one example being the martensite-austenite twinning that underlies macroscopic strain localization) and result in a large hysteresis. In order to optimize the use of this hysteretic behavior in energy storage and damping applications, we must first have a quantitative understanding of this transformation behavior. Prior results on shape memory alloys have been largely qualitative (i.e., mapping phase transformations through cracked oxide coatings or surface morphology). The PI developed and utilized new approaches to provide a quantitative, full-field characterization of phase transformation, conducting a comprehensive suite of experiments across multiple length scales and tying these results to theoretical and computational analysis. The research funded by this award utilized new combinations of scanning electron microscopy, diffraction, digital image correlation, and custom testing equipment and procedures to study phase transformation processes at a wide range of length scales, with a focus at small length scales with spatial resolution on the order of 1 nanometer. These experiments probe the basic connections between length scales during phase transformation. In addition to the insights gained on the fundamental <span class="hlt">mechanisms</span> driving transformations in shape memory alloys, the unique experimental methodologies developed under this award are applicable to a wide range of solid-to-solid phase transformations and other strain localization <span class="hlt">mechanisms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NatSR...4E7116Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014NatSR...4E7116Z&link_type=ABSTRACT"><span id="translatedtitle">Synthetically chemical-electrical <span class="hlt">mechanism</span> for controlling large scale reversible <span class="hlt">deformation</span> of liquid metal objects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Jie; Sheng, Lei; Liu, Jing</p> <p>2014-11-01</p> <p>Reversible <span class="hlt">deformation</span> of a machine holds enormous promise across many scientific areas ranging from <span class="hlt">mechanical</span> engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible <span class="hlt">deformation</span> through controlling the working materials via the synthetically chemical-electrical <span class="hlt">mechanism</span> (SCHEME). Such <span class="hlt">activity</span> incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former <span class="hlt">deformation</span> principles through converting electrical energy into <span class="hlt">mechanical</span> movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25408295','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25408295"><span id="translatedtitle">Synthetically chemical-electrical <span class="hlt">mechanism</span> for controlling large scale reversible <span class="hlt">deformation</span> of liquid metal objects.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, Jie; Sheng, Lei; Liu, Jing</p> <p>2014-01-01</p> <p>Reversible <span class="hlt">deformation</span> of a machine holds enormous promise across many scientific areas ranging from <span class="hlt">mechanical</span> engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible <span class="hlt">deformation</span> through controlling the working materials via the synthetically chemical-electrical <span class="hlt">mechanism</span> (SCHEME). Such <span class="hlt">activity</span> incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former <span class="hlt">deformation</span> principles through converting electrical energy into <span class="hlt">mechanical</span> movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks. PMID:25408295</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4236740','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4236740"><span id="translatedtitle">Synthetically chemical-electrical <span class="hlt">mechanism</span> for controlling large scale reversible <span class="hlt">deformation</span> of liquid metal objects</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhang, Jie; Sheng, Lei; Liu, Jing</p> <p>2014-01-01</p> <p>Reversible <span class="hlt">deformation</span> of a machine holds enormous promise across many scientific areas ranging from <span class="hlt">mechanical</span> engineering to applied physics. So far, such capabilities are still hard to achieve through conventional rigid materials or depending mainly on elastomeric materials, which however own rather limited performances and require complicated manipulations. Here, we show a basic strategy which is fundamentally different from the existing ones to realize large scale reversible <span class="hlt">deformation</span> through controlling the working materials via the synthetically chemical-electrical <span class="hlt">mechanism</span> (SCHEME). Such <span class="hlt">activity</span> incorporates an object of liquid metal gallium whose surface area could spread up to five times of its original size and vice versa under low energy consumption. Particularly, the alterable surface tension based on combination of chemical dissolution and electrochemical oxidation is ascribed to the reversible shape transformation, which works much more flexible than many former <span class="hlt">deformation</span> principles through converting electrical energy into <span class="hlt">mechanical</span> movement. A series of very unusual phenomena regarding the reversible configurational shifts are disclosed with dominant factors clarified. This study opens a generalized way to combine the liquid metal serving as shape-variable element with the SCHEME to compose functional soft machines, which implies huge potential for developing future smart robots to fulfill various complicated tasks. PMID:25408295</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989PNAOJ...1...57I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989PNAOJ...1...57I"><span id="translatedtitle"><span class="hlt">Active</span> optics experiments. II - Measurement of mirror <span class="hlt">deformation</span> by holographic method</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Itoh, Noboru; Mikami, Izumi; Miyawaki, Keizou; Sasaki, Aki; Tabata, Masao</p> <p></p> <p>An <span class="hlt">active</span> optics experiment was performed to study the feasibility of using an <span class="hlt">active</span> correction system for the Japanese National Large Telescope (Wilson, 1986). A thin mirror was <span class="hlt">deformed</span> with an <span class="hlt">active</span> support <span class="hlt">mechanism</span> and the mirror surface was measured by a holographic method. The experiment is performed for several cases of excess force distributions assigned at the supporting points. The results show good agreement with predictions from FEM analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016APS..MARH33012P&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016APS..MARH33012P&link_type=ABSTRACT"><span id="translatedtitle">Microscopic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in model thermoplastic elastomers by molecular dynamics simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Parker, Amanda; Rottler, Jörg</p> <p></p> <p>Thermoplastic elastomers (TPEs) can be formed by exploiting the nanostructured morphology of triblock copolymers. Glassy end-blocks phase separate to form spherical regions which act as physical cross-links for the soft rubbery phase. Molecular dynamics simulations of TPEs allow us to relate the microscopic <span class="hlt">mechanisms</span> <span class="hlt">active</span> during plastic <span class="hlt">deformation</span> to the macroscopic stress response. A coarse-grained bead-spring model of linear ABA triblock copolymers which forms the desired spherical morphology is used for pure stress and pure strain uniaxial <span class="hlt">deformations</span>. The systems are first equilibrated using a soft pair potential. We observe increased strain hardening in triblocks when compared to homopolymers of the same chain length in accordance with experiments. We connect variations in the stress response for systems of different chain lengths to the non-affine <span class="hlt">deformation</span> of chains and to the scale of phase separated regions. The stress response is also compared to rubbery elasticity models, taking into account the evolution of chain entanglements during <span class="hlt">deformation</span>. We observe void formation at the interfaces of glassy regions or where these regions have broken up at large strain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JMEP...21.2255W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JMEP...21.2255W"><span id="translatedtitle">A True-Stress Creep Model Based on <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> for Polycrystalline Materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Xijia; Williams, Steve; Gong, Diguang</p> <p>2012-11-01</p> <p>A true-stress creep model has been developed based on well-recognized <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, i.e., dislocation glide, dislocation climb, and grain boundary sliding. The model provides a physics-based description of the entire creep <span class="hlt">deformation</span> process with regards to the strain-time history (primary, secondary, and tertiary creep), rupture strain and lifetime, which finds good agreement with experimental observations for Waspaloy. A <span class="hlt">deformation-mechanism</span> map is constructed for Waspaloy, and a creep failure criterion is defined by the dominant <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> leading to intergranular/transgranular fracture. Thus, the model is a self-consistent tool for creep life prediction.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PMag...91.1070D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PMag...91.1070D"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in gold nanowires and nanoporous gold</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dou, R.; Derby, B.</p> <p>2011-03-01</p> <p>We present a study of the <span class="hlt">deformation</span> of gold nanowires of diameter 30-70 nm and nanoporous gold specimens with ligament diameter 5-10 nm, both produced by electrodeposition into anodised aluminium oxide templates. The nanowires show extensive surface slip steps and low dislocation densities with a few perfect dislocation loops, Shockley partial dislocations and microtwins observed after <span class="hlt">deformation</span>. Nanoporous specimens show <span class="hlt">deformation</span> localised to the nodes between the ligaments of the foamed structure, with high densities of microtwins and Shockley partial dislocations in these regions. Similar dislocation structures are seen in larger nanowires <span class="hlt">deformed</span> in bending. This is shown to be consistent with a strain gradient plasticity model for the <span class="hlt">deformation</span> of nanoporous gold, with the strain gradient accommodated by geometrically necessary twins and partial dislocations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8409E..31Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8409E..31Y"><span id="translatedtitle">Molecular modelling of structure and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of auxetic behaviour in the α-quartz structures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Yong Tao; Alderson, Andrew; Alderson, Kim Lesley</p> <p>2012-04-01</p> <p>Force field based simulation has been employed to predict the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of auxetic nano-materials having tetrahedral framework. The structure of α-quartz was studied in detail for subjecting to uniaxial loading along the Z direction. The cooperative dilation and rotation of tetrahedra acting concurrently were demonstrated to be the main <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of α-quartz, confirming previous analytical model. Slight tetrahedral distortion also existed for undeformed and <span class="hlt">deformed</span> structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8409E..31Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8409E..31Y"><span id="translatedtitle">Molecular modelling of structure and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of auxetic behaviour in the α-quartz structures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yao, Yong Tao; Alderson, Andrew; Alderson, Kim Lesley</p> <p>2011-11-01</p> <p>Force field based simulation has been employed to predict the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of auxetic nano-materials having tetrahedral framework. The structure of α-quartz was studied in detail for subjecting to uniaxial loading along the Z direction. The cooperative dilation and rotation of tetrahedra acting concurrently were demonstrated to be the main <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of α-quartz, confirming previous analytical model. Slight tetrahedral distortion also existed for undeformed and <span class="hlt">deformed</span> structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25920188','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25920188"><span id="translatedtitle">[Inflammasome: <span class="hlt">activation</span> <span class="hlt">mechanisms</span>].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Suárez, Raibel; Buelvas, Neudo</p> <p>2015-03-01</p> <p>Inflammation is a rapid biologic response of the immune system in vascular tissues, directed to eliminate stimuli capable of causing damage and begin the process of repair. The macromolecular complexes known as "inflammasomes" are formed by a receptor, either NOD (NLR) or ALR, the receptor absent in melanoma 2 (AIM2). In addition, the inflammasome is formed by the speck-like protein associated to apoptosis (ASC) and procaspase-1, that may be <span class="hlt">activated</span> by variations in the ionic and intracellular and extracellular ATP concentrations; and the loss of stabilization of the fagolisosomme by internalization of insoluble crystals and redox <span class="hlt">mechanisms</span>. As a result, there is <span class="hlt">activation</span> of the molecular platform and the processing of inflammatory prointerleukins to their <span class="hlt">active</span> forms. There are two modalities of <span class="hlt">activation</span> of the inflammasome: canonical and non-canonical, both capable of generating effector responses. Recent data associate NLRP 3, IL-1β and IL-18 in the pathogenesis of a variety of diseases, including atherosclerosis, type II diabetes, hyperhomocysteinemia, gout, malaria and hypertension. The inflammasome cascade is emerging as a new chemotherapeutic target in these diseases. In this review we shall discuss the <span class="hlt">mechanisms</span> of <span class="hlt">activation</span> and regulation of the inflammasome that stimulate, modulate and resolve inflammation. PMID:25920188</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006JNuM..356...70W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006JNuM..356...70W&link_type=ABSTRACT"><span id="translatedtitle">The role of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in flow localization of 316L stainless steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Xianglin; Pan, Xiao; Mabon, James C.; Li, Meimei; Stubbins, James F.</p> <p>2006-09-01</p> <p>Type 316 SS is widely used as a structural material in a variety of current accelerator driven systems and designs as well as in a number of current and advanced fission and fusion reactor concepts. The material is found to be very sensitive to irradiation damage in the temperature range of 150-400 °C, where low levels of irradiation exposure, as little as 0.1 dpa, can substantially reduce the uniform elongation in tensile tests. This process, where the plastic flow becomes highly localized resulting in very low overall ductility, is referred to as flow localization. The process controlling this restriction of flow is related to the difference between the yield and ultimate strengths such that dramatic irradiation-induced increases in the yield strength results in very limited plastic flow until necking. In this study, the temperature dependence of this process is examined in light of the operating <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. It is found that twinning is an important <span class="hlt">deformation</span> <span class="hlt">mechanism</span> at lower temperatures but is not available in the temperature range of concern since the stress to <span class="hlt">activate</span> twinning becomes excessively high. This limits the <span class="hlt">deformation</span> and leads to the flow localization process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT........83R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT........83R"><span id="translatedtitle"><span class="hlt">Mechanically</span> <span class="hlt">Active</span> Electrospun Materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robertson, Jaimee M.</p> <p></p> <p>Electrospinning, a technique used to fabricate small diameter polymer fibers, has been employed to develop unique, <span class="hlt">active</span> materials falling under two categories: (1) shape memory elastomeric composites (SMECs) and (2) water responsive fiber mats. (1) Previous work has characterized in detail the properties and behavior of traditional SMECs with isotropic fibers embedded in an elastomer matrix. The current work has two goals: (i) characterize laminated anisotropic SMECs and (ii) develop a fabrication process that is scalable for commercial SMEC manufacturing. The former ((i)) requires electrospinning aligned polymer fibers. The aligned fibers are similarly embedded in an elastomer matrix and stacked at various fiber orientations. The resulting laminated composite has a unique response to tensile <span class="hlt">deformation</span>: after stretching and releasing, the composite curls. This curling response was characterized based on fiber orientation. The latter goal ((ii)) required use of a dual-electrospinning process to simultaneously electrospin two polymers. This fabrication approach incorporated only industrially relevant processing techniques, enabling the possibility of commercial application of a shape memory rubber. Furthermore, the approach had the added benefit of increased control over composition and material properties. (2) The strong elongational forces experienced by polymer chains during the electrospinning process induce molecular alignment along the length of electrospun fibers. Such orientation is maintained in the fibers as the polymer vitrifies. Consequently, residual stress is stored in electrospun fiber mats and can be recovered by heating through the polymer's glass transition temperature. Alternatively, the glass transition temperature can be depressed by introducing a plasticizing agent. Poly(vinyl acetate) (PVAc) is plasticized by water, and its glass transition temperature is lowered below room temperature. Therefore, the residual stress can be relaxed at room</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011EL.....9627005Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011EL.....9627005Z"><span id="translatedtitle">NMR study on <span class="hlt">mechanisms</span> of ionic polymer-metal composites <span class="hlt">deformation</span> with water content</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhu, Zicai; Chen, Hualing; Wang, Yongquan; Luo, Bin; Chang, Longfei; Li, Bo; Chen, Luping</p> <p>2011-10-01</p> <p>Ionic polymer-metal composites (IPMCs) exhibit a large dynamic bending <span class="hlt">deformation</span> under exterior electric field. The states and proportions of water within the IPMCs have great effect on the IPMCs <span class="hlt">deformation</span> properties. This letter investigates the influence of the proportion changes of different types of water on the <span class="hlt">deformation</span>, which may disclose the working <span class="hlt">mechanisms</span> of the IPMCs. We give a <span class="hlt">deformation</span> trend of IPMCs with the reduction of water content firstly. Then by the method of nuclear magnetic resonance, various water types (water bonded to sulfonates, loosely bound water and free water) of IPMCs and their proportions are investigated in the drying process which corresponds to their different <span class="hlt">deformation</span> states. It is obtained that the <span class="hlt">deformation</span> properties of IPMCs depend strongly on their water content and the excess free water is responsible for the relaxation <span class="hlt">deformation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010APS..MARD17007D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2010APS..MARD17007D&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mechanisms</span> of Photo-Induced <span class="hlt">Deformations</span> of Liquid Crystal Elastomers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dawson, Nathan; Kuzyk, Mark; Neal, Jeremy; Luchette, Paul; Palffy-Muhoray, Peter</p> <p>2010-03-01</p> <p>Over a century ago, Alexander Graham Bell invented the photophone, which he used to transmit <span class="hlt">mechanical</span> information on a beam of light. We report on the use of an <span class="hlt">active</span> Fabry-Perot interferometer to encode and detect <span class="hlt">mechanical</span> information using the photomechanical effect of a liquid crystal elastomer (LCE) that is placed at a critical point between the reflectors. These are the first steps in the creation of ultra smart materials which require a large photomechanical response. Thus, understanding the underlying <span class="hlt">mechanisms</span> is critical. Only limited studies of the <span class="hlt">mechanisms</span> of the photomechanical effect, such as photo-isomerization, photo-reorientation and thermal effects have been studied in azo-dye-doped LCEs and in azo-dye-doped polymer fibers have been reported. The focus of our present work is to use the Fabry-Perot transducer geometry to study the underlying <span class="hlt">mechanisms</span> and to determine the relevant material parameters that are used to develop theoretical models of the response. We use various intensity-modulated optical wave forms to determine the frequency response of the material, which are used to predict the material response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JOM...tmp..208V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JOM...tmp..208V&link_type=ABSTRACT"><span id="translatedtitle">Acoustic Emission as a Tool for Exploring <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Magnesium and Its Alloys In Situ</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vinogradov, Alexei; Máthis, Kristian</p> <p>2016-06-01</p> <p>Structural performance of magnesium alloys depends strongly on specific <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> operating during <span class="hlt">mechanical</span> loading. Therefore, in situ monitoring of the acting <span class="hlt">mechanisms</span> is a key to performance tailoring. We review the capacity of the advanced acoustic emission (AE) technique to understand the interplay between two primary <span class="hlt">deformation</span> mechanisms—dislocation slip and twinning—in real time scale. Details of relative contributions of dislocation slip and <span class="hlt">deformation</span> twinning to the <span class="hlt">mechanical</span> response of pure Mg and Mg-Al alloy are discussed in view of AE results obtained with the aid of recently proposed spectral and signal categorization algorithms in conjunction with with neutron diffraction data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/20849563','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/20849563"><span id="translatedtitle"><span class="hlt">Deformation</span> Microstructure of a Reduced-<span class="hlt">Activation</span> Ferritic/Martensitic Steel Irradiated in HFIR</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hashimoto, N.; Klueh, R.L.; Ando, M.; Tanigawa, H.; Sawai, T.; Shiba, K.</p> <p>2003-09-15</p> <p>In order to determine the contributions of different microstructural features to strength and to <span class="hlt">deformation</span> mode, microstructure of <span class="hlt">deformed</span> flat tensile specimens of irradiated reduced <span class="hlt">activation</span> F82H (IEA heat) base metal (BM) and its tungsten inert-gas (TIG) weldments (weld metal and weld joint) were investigated by transmission electron microscopy (TEM), following fracture surface examination by scanning electron microscopy (SEM). After irradiation, the fracture surfaces of F82H BM and TIG weldment showed a martensitic mixed quasi-cleavage and ductile-dimple fracture. The microstructure of the <span class="hlt">deformed</span> region of irradiated F82H BM contained dislocation channels. This suggests that dislocation channeling could be the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in this steel, resulting in the loss of strain-hardening capacity. While, the necked region of the irradiated F82H TIG, where showed less hardening than F82H BM, showed <span class="hlt">deformation</span> bands only. From these results, it is suggested that the pre-irradiation microstructure, especially the dislocation density, could affect the post-irradiation <span class="hlt">deformation</span> mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26402601','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26402601"><span id="translatedtitle"><span class="hlt">Mechanically</span> <span class="hlt">Activated</span> Ion Channels.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ranade, Sanjeev S; Syeda, Ruhma; Patapoutian, Ardem</p> <p>2015-09-23</p> <p>Mechanotransduction, the conversion of physical forces into biochemical signals, is essential for various physiological processes such as the conscious sensations of touch and hearing, and the unconscious sensation of blood flow. <span class="hlt">Mechanically</span> <span class="hlt">activated</span> (MA) ion channels have been proposed as sensors of physical force, but the identity of these channels and an understanding of how <span class="hlt">mechanical</span> force is transduced has remained elusive. A number of recent studies on previously known ion channels along with the identification of novel MA ion channels have greatly transformed our understanding of touch and hearing in both vertebrates and invertebrates. Here, we present an updated review of eukaryotic ion channel families that have been implicated in mechanotransduction processes and evaluate the qualifications of the candidate genes according to specified criteria. We then discuss the proposed gating models for MA ion channels and highlight recent structural studies of mechanosensitive potassium channels. PMID:26402601</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......165G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......165G"><span id="translatedtitle">Crustal <span class="hlt">deformation</span> and volcanism at <span class="hlt">active</span> plate boundaries</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Geirsson, Halldor</p> <p></p> <p>Most of Earth's volcanoes are located near <span class="hlt">active</span> tectonic plate boundaries, where the tectonic plates move relative to each other resulting in <span class="hlt">deformation</span>. Likewise, subsurface magma movement and pressure changes in magmatic systems can cause measurable <span class="hlt">deformation</span> of the Earth's surface. The study of the shape of Earth and therefore studies of surface <span class="hlt">deformation</span> is called geodesy. Modern geodetic techniques allow precise measurements (˜1 mm accuracy) of <span class="hlt">deformation</span> of tectonic and magmatic systems. Because of the spatial correlation between tectonic boundaries and volcanism, the tectonic and volcanic <span class="hlt">deformation</span> signals can become intertwined. Thus it is often important to study both tectonic and volcanic <span class="hlt">deformation</span> processes simultaneously, when one is trying to study one of the systems individually. In this thesis, I present research on crustal <span class="hlt">deformation</span> and magmatic processes at <span class="hlt">active</span> plate boundaries. The study areas cover divergent and transform plate boundaries in south Iceland and convergent and transform plate boundaries in Central America, specifically Nicaragua and El Salvador. The study is composed of four main chapters: two of the chapters focus on the magma plumbing system of Hekla volcano, Iceland and the plate boundary in south Iceland; one chapter focuses on shallow controls of explosive volcanism at Telica volcano, Nicaragua; and the fourth chapter focuses on co- and post-seismic <span class="hlt">deformation</span> from a Mw = 7.3 earthquake which occurred offshore El Salvador in 2012. Hekla volcano is located at the intersection of a transform zone and a rift zone in Iceland and thus is affected by a combination of shear and extensional strains, in addition to co-seismic and co-rifting <span class="hlt">deformation</span>. The inter-eruptive <span class="hlt">deformation</span> signal from Hekla is subtle, as observed by a decade (2000-2010) of GPS data in south Iceland. A simultaneous inversion of this data for parameters describing the geometry and source characteristics of the magma chamber at Hekla, and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70030325','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70030325"><span id="translatedtitle">Temporal evolution of continental lithospheric strength in <span class="hlt">actively</span> <span class="hlt">deforming</span> regions</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Thatcher, W.; Pollitz, F.F.</p> <p>2008-01-01</p> <p>It has been agreed for nearly a century that a strong, load-bearing outer layer of earth is required to support mountain ranges, transmit stresses to <span class="hlt">deform</span> <span class="hlt">active</span> regions and store elastic strain to generate earthquakes. However the dept and extent of this strong layer remain controversial. Here we use a variety of observations to infer the distribution of lithospheric strength in the <span class="hlt">active</span> western United States from seismic to steady-state time scales. We use evidence from post-seismic transient and earthquake cycle <span class="hlt">deformation</span> reservoir loading glacio-isostatic adjustment, and lithosphere isostatic adjustment to large surface and subsurface loads. The nearly perfectly elastic behavior of Earth's crust and mantle at the time scale of seismic wave propagation evolves to that of a strong, elastic crust and weak, ductile upper mantle lithosphere at both earthquake cycle (EC, ???10?? to 103 yr) and glacio-isostatic adjustment (GIA, ???103 to 104 yr) time scales. Topography and gravity field correlations indicate that lithosphere isostatic adjustment (LIA) on ???106-107 yr time scales occurs with most lithospheric stress supported by an upper crust overlying a much weaker ductile subtrate. These comparisons suggest that the upper mantle lithosphere is weaker than the crust at all time scales longer than seismic. In contrast, the lower crust has a chameleon-like behavior, strong at EC and GIA time scales and weak for LIA and steady-state <span class="hlt">deformation</span> processes. The lower crust might even take on a third identity in regions of rapid crustal extension or continental collision, where anomalously high temperatures may lead to large-scale ductile flow in a lower crustal layer that is locally weaker than the upper mantle. Modeling of lithospheric processes in <span class="hlt">active</span> regions thus cannot use a one-size-fits-all prescription of rheological layering (relation between applied stress and <span class="hlt">deformation</span> as a function of depth) but must be tailored to the time scale and tectonic</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/sir/2008/5090/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/sir/2008/5090/"><span id="translatedtitle">Evolution of <span class="hlt">Deformation</span> Studies on <span class="hlt">Active</span> Hawaiian Volcanoes</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Decker, Robert; Okamura, Arnold; Miklius, Asta; Poland, Michael</p> <p>2008-01-01</p> <p>Everything responds to pressure, even rocks. <span class="hlt">Deformation</span> studies involve measuring and interpreting the changes in elevations and horizontal positions of the land surface or sea floor. These studies are variously referred to as geodetic changes or ground-surface <span class="hlt">deformations</span> and are sometimes indexed under the general heading of geodesy. <span class="hlt">Deformation</span> studies have been particularly useful on <span class="hlt">active</span> volcanoes and in <span class="hlt">active</span> tectonic areas. A great amount of time and energy has been spent on measuring geodetic changes on Kilauea and Mauna Loa Volcanoes in Hawai`i. These changes include the build-up of the surface by the piling up and ponding of lava flows, the changes in the surface caused by erosion, and the uplift, subsidence, and horizontal displacements of the surface caused by internal processes acting beneath the surface. It is these latter changes that are the principal concern of this review. A complete and objective review of <span class="hlt">deformation</span> studies on <span class="hlt">active</span> Hawaiian volcanoes would take many volumes. Instead, we attempt to follow the evolution of the most significant observations and interpretations in a roughly chronological way. It is correct to say that this is a subjective review. We have spent years measuring and recording <span class="hlt">deformation</span> changes on these great volcanoes and more years trying to understand what makes these changes occur. We attempt to make this a balanced as well as a subjective review; the references are also selective rather than exhaustive. Geodetic changes caused by internal geologic processes vary in magnitude from the nearly infinitesimal - one micron or less, to the very large - hundreds of meters. Their apparent causes also are varied and include changes in material properties and composition, atmospheric pressure, tidal stress, thermal stress, subsurface-fluid pressure (including magma pressure, magma intrusion, or magma removal), gravity, and tectonic stress. <span class="hlt">Deformation</span> is measured in units of strain or displacement. For example, tilt</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983stan.reptQ....N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983stan.reptQ....N"><span id="translatedtitle">Models for rupture <span class="hlt">mechanics</span> of plate boundaries and crustal <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nur, A.</p> <p>1983-02-01</p> <p>The role of pull aparts and pushups in transcurrent systems, the rotation of faults and blocks within transcurrent fault systems, the role of accretion tectonics in plate boundary <span class="hlt">deformation</span>, and power law creep behavior and the yielding at plate boundaries were investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15519346','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15519346"><span id="translatedtitle">On the <span class="hlt">mechanism</span> of cell lysis by <span class="hlt">deformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Takamatsu, Hiroshi; Takeya, Ryu; Naito, Seiji; Sumimoto, Hideki</p> <p>2005-01-01</p> <p>In this study, we identify the extent of <span class="hlt">deformation</span> that causes cell lysis using a simple technique where a drop of cell suspension is compressed by two flat plates. The viability of human prostatic adenocarcinoma PC-3 cells in solutions of various concentrations of NaCl is determined as a function of the gap size between the plates. The viability declines with decreasing gap size in the following order: 700 mM >150 mM >75 mM NaCl. This is considered to be due to the difference in cell size, which is caused by the osmotic volume change before <span class="hlt">deformation</span>; cell diameter becomes smaller in a solution of higher NaCl concentration, which appears to increase the survival ratio in a given gap size. The <span class="hlt">deformation</span>-induced decrease in cell viability is correlated with the cell surface strain, which is dependent on the increase in surface area, irrespective of NaCl concentration. In addition, the treatment of cells with cytochalasin D results in the disappearance of cortical actin filaments and a marked drop in the viability, indicating that cell lysis is closely related to the <span class="hlt">deformation</span> of the cytoskeleton. PMID:15519346</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26168433','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26168433"><span id="translatedtitle">Automatic Segmentation of <span class="hlt">Mechanically</span> Inhomogeneous Tissues Based on <span class="hlt">Deformation</span> Gradient Jump.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Witzenburg, Colleen M; Dhume, Rohit Y; Lake, Spencer P; Barocas, Victor H</p> <p>2016-01-01</p> <p>Variations in properties, <span class="hlt">active</span> behavior, injury, scarring, and/or disease can all cause a tissue's <span class="hlt">mechanical</span> behavior to be heterogeneous. Advances in imaging technology allow for accurate full-field displacement tracking of both in vitro and in vivo <span class="hlt">deformation</span> from an applied load. While detailed strain fields provide some insight into tissue behavior, material properties are usually determined by fitting stress-strain behavior with a constitutive equation. However, the determination of the <span class="hlt">mechanical</span> behavior of heterogeneous soft tissue requires a spatially varying constitutive equation (i.e., one in which the material parameters vary with position). We present an approach that computationally dissects the sample domain into many homogeneous subdomains, wherein subdomain boundaries are formed by applying a betweenness based graphical analysis to the <span class="hlt">deformation</span> gradient field to identify locations with large discontinuities. This novel partitioning technique successfully determined the shape, size and location of regions with locally similar material properties for: (1) a series of simulated soft tissue samples prescribed with both abrupt and gradual changes in anisotropy strength, prescribed fiber alignment, stiffness, and nonlinearity, (2) tissue analogs (PDMS and collagen gels) which were tested biaxially and speckle tracked (3) and soft tissues which exhibited a natural variation in properties (cadaveric supraspinatus tendon), a pathologic variation in properties (thoracic aorta containing transmural plaque), and <span class="hlt">active</span> behavior (contracting cardiac sheet). The routine enables the dissection of samples computationally rather than physically, allowing for the study of small tissues specimens with unknown and irregular inhomogeneity. PMID:26168433</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.V43B3141P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.V43B3141P"><span id="translatedtitle">Focal <span class="hlt">Mechanisms</span> for Local Earthquakes within a Rapidly <span class="hlt">Deforming</span> Rhyolitic Magma System, Laguna del Maule, Chile</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peterson, D. E.; Keranen, K. M.; Cardona, C.; Thurber, C. H.; Singer, B. S.</p> <p>2015-12-01</p> <p>Large shallow rhyolitic magma systems like the one underlying the Laguna del Maule Volcanic Field (LdM) atop the Southern Andes, Chile, that comprises the largest concentration of rhyolitic lava and tephra younger than 20 ka at earth's surface, are capable of producing modest to very large explosive eruptions. Moreover, LdM is currently exhibiting magma migration, reservoir growth, and crustal <span class="hlt">deformation</span> at rates higher than any volcano that is not <span class="hlt">actively</span> erupting. The long-term build-up of a large silicic magmatic system toward an eruption has yet to be monitored, therefore, precursory phenomena are poorly understood. In January of 2015, 12 broadband, 3-component seismometers were installed at LdM to detect local microearthquakes and tele-seismic events with the goals of determining the migration paths of fluids as well as the boundaries of the magma chamber beneath LdM. These stations complement the 6 permanent stations installed by the Southern Andes Volcano Observatory in 2011. Focal <span class="hlt">mechanisms</span> were calculated using FOCMEC (Snoke et al., 1984) and P-wave first motions for local events occurring between January and March of 2015 using these 18 broadband stations. Results from six of the largest local events indicate a mixture of normal and reverse faulting at shallow (<10 km) depths surrounding the lake. This may be associated with the opening of fractures to accommodate rising magma in the subsurface and/or stresses induced by the rapid <span class="hlt">deformation</span>. Two of these events occurred near the center of maximum <span class="hlt">deformation</span> where seismic swarms have previously been identified. Focal <span class="hlt">mechanisms</span> from smaller magnitude events will be calculated to better delineate subsurface structure. Source <span class="hlt">mechanisms</span> will be refined using P-S amplitude ratios and full waveform inversion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001MMTB...32..697L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001MMTB...32..697L"><span id="translatedtitle">Physical modeling of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of semisolid bodies and a <span class="hlt">mechanical</span> criterion for hot tearing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lahaie, D. J.; Bouchard, M.</p> <p>2001-08-01</p> <p>The <span class="hlt">mechanical</span> response of a semisolid body to an applied, uniaxial strain rate has been expressed as a function of strain by modifying an existing analysis based on an idealized representation of the microstructure. An existing <span class="hlt">mechanical</span> criterion for hot tearing of the semisolid body has been adapted to the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. The resulting hot tearing model shows that the strength of the body depends on the strain, the viscosity of the intergranular fluid, the solid fraction, the isothermal compressibility of the fluid, the surface tension of the liquid, the limiting liquid-film thickness for viscous flow and a parameter m, which describes microstructure. The effect of each parameter on the <span class="hlt">mechanical</span> response and the onset of hot tearing has been examined for ranges of values relevant to aluminum alloys and the direct-chill (DC) casting process. The parameter testing has shown that the <span class="hlt">mechanical</span> response predicted by the model agrees well with some experimental data for both the <span class="hlt">mechanisms</span> of fracture and the parameters that govern the process. An adjustment of unknown model parameters to experimental data would permit use of the model as a constitutive law and a fracture criterion for numerical modeling of hot tearing during the solidification of Al alloys by DC casting.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910053191&hterms=anisotropic+material&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Danisotropic%2Bmaterial','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910053191&hterms=anisotropic+material&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Danisotropic%2Bmaterial"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in negative Poisson's ratio materials - Structural aspects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lakes, R.</p> <p>1991-01-01</p> <p>Poisson's ratio in materials is governed by the following aspects of the microstructure: the presence of rotational degrees of freedom, non-affine <span class="hlt">deformation</span> kinematics, or anisotropic structure. Several structural models are examined. The non-affine kinematics are seen to be essential for the production of negative Poisson's ratios for isotropic materials containing central force linkages of positive stiffness. Non-central forces combined with pre-load can also give rise to a negative Poisson's ratio in isotropic materials. A chiral microstructure with non-central force interaction or non-affine <span class="hlt">deformation</span> can also exhibit a negative Poisson's ratio. Toughness and damage resistance in these materials may be affected by the Poisson's ratio itself, as well as by generalized continuum aspects associated with the microstructure.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JMPSo..53..525B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JMPSo..53..525B"><span id="translatedtitle">Finite <span class="hlt">deformations</span> of metal cylinders subjected to electromagnetic fields and <span class="hlt">mechanical</span> forces</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bilyk, S. R.; Ramesh, K. T.; Wright, T. W.</p> <p>2005-03-01</p> <p>Strong electromagnetic (EM) fields coupled with <span class="hlt">mechanical</span> loads may have a profound effect on <span class="hlt">deforming</span> bodies. The continuum description of the plastic <span class="hlt">deformation</span> of solids under electric fields and <span class="hlt">mechanical</span> loads essentially involves the coupling of the field equations of continuum <span class="hlt">mechanics</span> with Maxwell's equations. This analysis considers the effects of large EM fields on solid metal cylinders undergoing plastic <span class="hlt">deformations</span>. Other researchers have used an electroplastic effect to explain previous EM and <span class="hlt">mechanically</span> loaded experimental results. We examine whether it is necessary to invoke this controversial <span class="hlt">mechanism</span>. First, we consider only EM loading and solve the transient EM distribution in a solid metal cylinder. This determines the EM time scales as compared to thermal diffusion time scales. Next, at the continuum level, we present the <span class="hlt">mechanical</span> problem of quasi-static finite compressive <span class="hlt">deformations</span> incorporating thermal expansion, strain hardening, strain rate sensitivity, thermal softening, and heat conduction. A viscoplastic model that is applicable over a wide range of strain rates (10 -4-10 6 s -1) characterizes the material response. Finally, we consider a metal cylinder subjected to uni-axial <span class="hlt">mechanical</span> loading as well as high axial current pulses. The material is assumed to be isotropic with the plastic incompressibility constraint. The <span class="hlt">deformations</span> are assumed to remain axisymmetric and no instabilities in the cylinder are considered. Coupled effects of Joule heating and the Lorentz force on the quasi-static <span class="hlt">deformations</span> are examined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22063676','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22063676"><span id="translatedtitle"><span class="hlt">Mechanical</span> and microstructural characterization of 6061 aluminum alloy strips severely <span class="hlt">deformed</span> by Dissimilar Channel Angular Pressing</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tan, Evren; Kibar, Alp Aykut; Guer, C. Hakan</p> <p>2011-04-15</p> <p>Dissimilar Channel Angular Pressing (DCAP) is a severe plastic <span class="hlt">deformation</span> technique to improve the <span class="hlt">mechanical</span> properties of flat products by producing ultrafine grains. In this study, the changes in the microstructure and <span class="hlt">mechanical</span> properties of 6061 Al-alloy strips <span class="hlt">deformed</span> by various numbers of DCAP passes were investigated. Some DCAPed samples were also held at 200 deg. C and 350 deg. C to investigate the effect of post-annealing. <span class="hlt">Mechanical</span> properties were determined by hardness and tension tests; and microstructural changes were investigated by TEM analysis. Up to a critical level of plastic strain, remarkable improvements have been observed in the strength and hardness of the severely <span class="hlt">deformed</span> strips; and the improvements have been explained by variations in grain size, dislocation structure, and formation of subgrains. - Research Highlights: {yields}Dissimilar Channel Angular Pressing (DCAP). {yields}Severe plastic <span class="hlt">deformation</span> (SPD). {yields}Transmission Electron Microscopy of the 6061 Al alloy. {yields}<span class="hlt">Mechanical</span> Properties of 6061 Al alloy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27151628','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27151628"><span id="translatedtitle">Graphene Topographies: Multiscale Graphene Topographies Programmed by Sequential <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> (Adv. Mater. 18/2016).</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chen, Po-Yen; Sodhi, Jaskiranjeet; Qiu, Yang; Valentin, Thomas M; Steinberg, Ruben Spitz; Wang, Zhongying; Hurt, Robert H; Wong, Ian Y</p> <p>2016-05-01</p> <p>P.-Y. Chen, R. H. Hurt, I. Y. Wong and co-workers demonstrate a hierarchical graphene surface architecture generated by using various sequences and combinations of extreme <span class="hlt">mechanical</span> <span class="hlt">deformation</span>, as shown in the false-colored SEM image. As described on page 3564, the sequential patterning approach enables the design of feature sizes and orientations across multiple length scales which are retained during <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of similar extent. This results in sequence-dependent surface topographies with structural memory. PMID:27151628</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGeo...85...58W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGeo...85...58W"><span id="translatedtitle">Coherence between geodetic and seismic <span class="hlt">deformation</span> in a context of slow tectonic <span class="hlt">activity</span> (SW Alps, France)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Walpersdorf, A.; Sue, C.; Baize, S.; Cotte, N.; Bascou, P.; Beauval, C.; Collard, P.; Daniel, G.; Dyer, H.; Grasso, J.-R.; Hautecoeur, O.; Helmstetter, A.; Hok, S.; Langlais, M.; Menard, G.; Mousavi, Z.; Ponton, F.; Rizza, M.; Rolland, L.; Souami, D.; Thirard, L.; Vaudey, P.; Voisin, C.; Martinod, J.</p> <p>2015-04-01</p> <p>A dense, local network of 30 geodetic markers covering a 50 × 60 km2 area in the southwestern European Alps (Briançon region) has been temporarily surveyed in 1996, 2006 and 2011 by GPS. The aim is to measure the current <span class="hlt">deformation</span> in this seismically <span class="hlt">active</span> area. The study zone is characterized by a majority of extensional and dextral focal <span class="hlt">mechanisms</span>, along north-south to N160 oriented faults. The combined analysis of the three measurement campaigns over 15 years and up to 16 years of permanent GPS data from the French RENAG network now enables to assess horizontal velocities below 1 mm/year within the local network. The long observation interval and the redundancy of the dense campaign network measurement help to constrain a significant local <span class="hlt">deformation</span> pattern in the Briançon region, yielding an average E-W extension of 16 ± 11 nanostrain/year. We compare the geodetic <span class="hlt">deformation</span> field to the seismic <span class="hlt">deformation</span> rate cumulated over 37 years, and obtain good coherencies both in amplitude and direction. Moreover, the horizontal <span class="hlt">deformation</span> localized in the Briançon region represents a major part of the Adriatic-European relative plate motion. However, the average uplift of the network in an extensional setting needs the presence of buoyancy forces in addition to plate tectonics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/72423','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/72423"><span id="translatedtitle">Defects, <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and phase stabilities in Nb-based B2 compounds</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hou, D.H.; Shyue, J.; Yang, S.S.; Fraser, H.L.</p> <p>1994-12-31</p> <p><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> have been determined for compounds based on Nb{sub 3}Al containing various additions of Ti. These compounds exhibit the B2 crystal structure and <span class="hlt">deform</span> by <span class="hlt">activation</span> of one or more of the following slip systems, namely {l_angle}111{r_angle}{l_brace}110{r_brace}, {l_angle}111{r_angle}{l_brace}112{r_brace} and {l_angle}111{r_angle}{l_brace}123{r_brace}. The dislocations are dissociated as superpartial pairs, each with Burgers vector, b, given by b=1/2{l_angle}111{r_angle}, which bound a ribbon of antiphase boundary. Attempts have been made to determine the ordering temperatures and the ordering energy of these compounds. Estimates of the site occupancy of these nonstoichiometric B2 compounds have also been determined by the ALCHEMI technique. The phase stabilities of these compounds have been determined over a wide range of temperatures and the effect of these on <span class="hlt">mechanical</span> properties has been assessed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MMTA...47...49M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MMTA...47...49M"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Austenitic TRIP/TWIP Steel as a Function of Temperature</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Martin, Stefan; Wolf, Steffen; Martin, Ulrich; Krüger, Lutz; Rafaja, David</p> <p>2016-01-01</p> <p>A high-alloy austenitic CrMnNi steel was <span class="hlt">deformed</span> at temperatures between 213 K and 473 K (-60 °C and 200 °C) and the resulting microstructures were investigated. At low temperatures, the <span class="hlt">deformation</span> was mainly accompanied by the direct martensitic transformation of γ-austenite to α'-martensite (fcc → bcc), whereas at ambient temperatures, the transformation via ɛ-martensite (fcc → hcp → bcc) was observed in <span class="hlt">deformation</span> bands. <span class="hlt">Deformation</span> twinning of the austenite became the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> at 373 K (100 °C), whereas the conventional dislocation glide represented the prevailing <span class="hlt">deformation</span> mode at 473 K (200 °C). The change of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> was attributed to the temperature dependence of both the driving force of the martensitic γ → α' transformation and the stacking fault energy of the austenite. The continuous transition between the ɛ-martensite formation and the twinning could be explained by different stacking fault arrangements on every second and on each successive {111} austenite lattice plane, respectively, when the stacking fault energy increased. A continuous transition between the transformation-induced plasticity effect and the twinning-induced plasticity effect was observed with increasing <span class="hlt">deformation</span> temperature. Whereas the formation of α'-martensite was mainly responsible for increased work hardening, the stacking fault configurations forming ɛ-martensite and twins induced additional elongation during tensile testing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.5231R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.5231R"><span id="translatedtitle">Dislocation creep accommodated Grain Boundary Sliding: A high strain rate/low temperature <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in calcite ultramylonites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rogowitz, Anna; Grasemann, Bernhard</p> <p>2014-05-01</p> <p>Grain boundary sliding (GBS) is an important grain size sensitive <span class="hlt">deformation</span> <span class="hlt">mechanism</span> that is often associated with extreme strain localization and superplasticity. Another <span class="hlt">mechanism</span> has to operate simultaneously to GBS in order to prevent overlaps and voids between sliding grains. One of the most common accommodating <span class="hlt">mechanisms</span> is diffusional creep but, recently, dislocation creep has been reported to operate simultaneous to GBS. Due to the formation of a flanking structure in nearly pure calcite marble on Syros (Cyclades, Greece) at lower greenschist facies conditions, an extremely fine grained ultramylonite developed. The microstructure of the layer is characterized by (1) calcite grains with an average grain size of 3.6 µm (developed by low temperature/high strain rate grain boundary migration recrystallization, BLG), (2) grain boundary triple junctions with nearly 120° angles and (3) small cavities preferentially located at triple junctions and at grain boundaries in extension. These features suggest that the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> was GBS. In order to get more information on the accommodation <span class="hlt">mechanism</span> detailed microstructural and textural analyses have been performed on a FEI Quanta 3D FEG instrument equipped with an EDAX Digiview IV EBSD camera. The misorientation distribution curves for correlated and uncorrelated grains follow almost perfect the calculated theoretical curve for a random distribution, which is typical for polycrystalline material <span class="hlt">deformed</span> by GBS. However, the crystallographic preferred orientation indicates that dislocation creep might have operated simultaneously. We also report Zener-Stroh cracks resulting from dislocation pile up, indicating that dislocation movement was <span class="hlt">active</span>. We, therefore, conclude that the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> was dislocation creep accommodated grain boundary sliding. This is consistent with the observed grain size range that plots at the field boundary between grain size insensitive and grain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511801D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511801D"><span id="translatedtitle">Ductile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of synthetic halite: a full field measurement approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dimanov, Alexandre; Bourcier, Mathieu; Héripré, Eva; Bornert, Michel; Raphanel, Jean</p> <p>2013-04-01</p> <p>Halite is a commonly used analog polycristalline material. Compared to most rock forming minerals, halite exhibits extensively ductile behavior at even low temperatures and fast <span class="hlt">deformation</span> rates. Therefore, it allows an easier study of the fundamental <span class="hlt">mechanisms</span> of crystal plasticity, recrystallization, grain growth and texture development than any other mineral. Its high solubility also makes it an ideal candidate for investigating pressure solution creep. Most importantly, halite is very convenient to study the interactions of simultaneously occurring <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. We investigated uniaxial <span class="hlt">deformation</span> of pure synthetic NaCl polycrystals with controlled grain sizes and grain size distributions at room and moderate temperatures (400°C). The <span class="hlt">mechanical</span> tests were combined with "in-situ" optical and scanning electron microscopy, in order to perform 2D digital image correlation (2D-DIC) and to obtain the full surface strain fields at the sample scale and at the scales of the microstructure. We observed dominantly intracrystalline plasticity, as revealed by the occurrence of physical slip lines on the surface of individual grains and of <span class="hlt">deformation</span> bands at the microstructure (aggregate) scale, as revealed by DIC. Crystal orientation mapping (performed by EBSD) allowed relating the latter to the traces of crystallographic slip planes and inferring the <span class="hlt">active</span> slip systems considering the macroscopic stress state and computing Schmid factors. The strain heterogeneities are more pronounced at low temperature, at both the aggregate scale and within individual grains. The local <span class="hlt">activity</span> of slip systems strongly depends on the relative crystallographic and interfacial orientations of the adjacent grains with respect to the loading direction. The easy glide {110} <110> systems are not the only <span class="hlt">active</span> ones. We could identify the <span class="hlt">activity</span> of all slip systems, especially near grain boundaries, which indicates local variations of the stress state. But, we also clearly</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4270353','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4270353"><span id="translatedtitle"><span class="hlt">Active</span> Printed Materials for Complex Self-Evolving <span class="hlt">Deformations</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Raviv, Dan; Zhao, Wei; McKnelly, Carrie; Papadopoulou, Athina; Kadambi, Achuta; Shi, Boxin; Hirsch, Shai; Dikovsky, Daniel; Zyracki, Michael; Olguin, Carlos; Raskar, Ramesh; Tibbits, Skylar</p> <p>2014-01-01</p> <p>We propose a new design of complex self-evolving structures that vary over time due to environmental interaction. In conventional 3D printing systems, materials are meant to be stable rather than <span class="hlt">active</span> and fabricated models are designed and printed as static objects. Here, we introduce a novel approach for simulating and fabricating self-evolving structures that transform into a predetermined shape, changing property and function after fabrication. The new locally coordinated bending primitives combine into a single system, allowing for a global <span class="hlt">deformation</span> which can stretch, fold and bend given environmental stimulus. PMID:25522053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25522053','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25522053"><span id="translatedtitle"><span class="hlt">Active</span> printed materials for complex self-evolving <span class="hlt">deformations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Raviv, Dan; Zhao, Wei; McKnelly, Carrie; Papadopoulou, Athina; Kadambi, Achuta; Shi, Boxin; Hirsch, Shai; Dikovsky, Daniel; Zyracki, Michael; Olguin, Carlos; Raskar, Ramesh; Tibbits, Skylar</p> <p>2014-01-01</p> <p>We propose a new design of complex self-evolving structures that vary over time due to environmental interaction. In conventional 3D printing systems, materials are meant to be stable rather than <span class="hlt">active</span> and fabricated models are designed and printed as static objects. Here, we introduce a novel approach for simulating and fabricating self-evolving structures that transform into a predetermined shape, changing property and function after fabrication. The new locally coordinated bending primitives combine into a single system, allowing for a global <span class="hlt">deformation</span> which can stretch, fold and bend given environmental stimulus. PMID:25522053</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5987','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5987"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> is a-Phase Silicon Nitride Ceramics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>J. A. Schneider; A. K. Mukherjee</p> <p>1998-08-12</p> <p>Changes of phase composition and morphology were investigated in Si{sub 3}N{sub 4} both before and after compressive <span class="hlt">deformation</span> testing. Si{sub 3}N{sub 4} specimens, with 5 wt% Y{sub 2}O{sub 3} and 5 wt% MgAl{sub 2}O{sub 4} additives, were rapidly consolidated to preserve the initial, metastable {alpha}-phase present in the Si{sub 3}N{sub 4} starting powders. Constant strain rate compression tests were used to evaluate the strain rate dependency of the flow stress. At 1723 K, a flow stress dependency value of n = 2 was observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApPhL.108o1903W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApPhL.108o1903W"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of bent Si nanowires governed by the sign and magnitude of strain</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Lihua; Kong, Deli; Xin, Tianjiao; Shu, Xinyu; Zheng, Kun; Xiao, Lirong; Sha, Xuechao; Lu, Yan; Zhang, Ze; Han, Xiaodong; Zou, Jin</p> <p>2016-04-01</p> <p>In this study, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of bent Si nanowires are investigated at the atomic scale with bending strain up to 12.8%. The sign and magnitude of the applied strain are found to govern their <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, in which the dislocation types (full or partial dislocations) can be affected by the sign (tensile or compressive) and magnitude of the applied strain. In the early stages of bending, plastic <span class="hlt">deformation</span> is controlled by 60° full dislocations. As the bending increases, Lomer dislocations can be frequently observed. When the strain increases to a significant level, 90° partial dislocations induced from the tensile surfaces of the bent nanowires are observed. This study provides a deeper understanding of the effect of the sign and magnitude of the bending strain on the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in bent Si nanowires.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009IJMPB..23.1816K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009IJMPB..23.1816K"><span id="translatedtitle"><span class="hlt">Deformation</span> Behaviors of Thermo-<span class="hlt">Mechanically</span> Processed Zr-Nb-P Alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ko, San; Hong, Sun Ig</p> <p></p> <p><span class="hlt">Deformation</span> behaviors of Zr-1.5 wt. % Nb alloys with no phosphorus addition and with various phosphorous contents (20 ppm, 160 ppm) were investigated in this study. The flow stress of Zr-1.5 Nb increased with the addition of 20~160 ppm phosphorous over a temperature range from room temperature to 450C. The dislocation density appeared to increase with increase of phosphorous content. The increase of strength with phosphorous addition may be linked to the increase of dislocation density. The increase of dislocation density with a higher phosphorous content can be associated with the increase of statistically stored dislocation due to a lower recovery rate. The <span class="hlt">activation</span> volume decreased from 650~750 b3 to 450`550 b3 with the addition of 160 ppm phosphorous at room temperature. The rate-controlling <span class="hlt">mechanism</span> of the <span class="hlt">deformation</span> of Zr-Nb-P alloy is thought to be the dislocation-solute interaction in which the segregation of alloying elements such as oxygen and phosphorous atoms affects the <span class="hlt">activation</span> length of dislocations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22163172','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22163172"><span id="translatedtitle">Microstructure, strengthening <span class="hlt">mechanisms</span> and hot <span class="hlt">deformation</span> behavior of an oxide-dispersion strengthened UFG Al6063 alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Asgharzadeh, H.; Kim, H.S.; Simchi, A.</p> <p>2013-01-15</p> <p>An ultrafine-grained Al6063/Al{sub 2}O{sub 3} (0.8 vol.%, 25 nm) nanocomposite was prepared via powder metallurgy route through reactive <span class="hlt">mechanical</span> alloying and hot powder extrusion. Scanning electron microcopy, transmission electron microscopy, and back scattered electron diffraction analysis showed that the grain structure of the nanocomposite is trimodal and composed of nano-size grains (< 0.1 {mu}m), ultrafine grains (0.1-1 {mu}m), and micron-size grains (> 1 {mu}m) with random orientations. Evaluation of the <span class="hlt">mechanical</span> properties of the nanocomposite based on the strengthening-<span class="hlt">mechanism</span> models revealed that the yield strength of the ultrafine-grained nanocomposite is mainly controlled by the high-angle grain boundaries rather than nanometric alumina particles. Hot <span class="hlt">deformation</span> behavior of the material at different temperatures and strain rates was studied by compression test and compared to coarse-grained Al6063 alloy. The <span class="hlt">activation</span> energy of the hot <span class="hlt">deformation</span> process for the nanocomposite was determined to be 291 kJ mol{sup -1}, which is about 64% higher than that of the coarse-grained alloy. Detailed microstructural analysis revealed that dynamic recrystallization is responsible for the observed <span class="hlt">deformation</span> softening in the ultrafine-grained nanocomposite. - Highlights: Black-Right-Pointing-Pointer The strengthening <span class="hlt">mechanisms</span> of Al6063/Al{sub 2}O{sub 3} nanocomposite were evaluated. Black-Right-Pointing-Pointer Hot <span class="hlt">deformation</span> behavior of the nanocomposite was studied. Black-Right-Pointing-Pointer The hot <span class="hlt">deformation</span> <span class="hlt">activation</span> energy was determined using consecutive models. Black-Right-Pointing-Pointer The restoration <span class="hlt">mechanisms</span> and microstructural changes are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SMaS...25e4002S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SMaS...25e4002S"><span id="translatedtitle">The influence of large <span class="hlt">deformations</span> on <span class="hlt">mechanical</span> properties of sinusoidal ligament structures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strek, Tomasz; Jopek, Hubert; Wojciechowski, Krzysztof W.</p> <p>2016-05-01</p> <p>Studies of <span class="hlt">mechanical</span> properties of materials, both theoretical and experimental, usually deal with linear characteristics assuming a small range of <span class="hlt">deformations</span>. In particular, not much research has been published devoted to large <span class="hlt">deformations</span> of auxetic structures – i.e. structures exhibiting negative Poisson’s ratio. This paper is focused on <span class="hlt">mechanical</span> properties of selected structures that are subject to large <span class="hlt">deformations</span>. Four examples of structure built of sinusoidal ligaments are studied and for each geometry the impact of <span class="hlt">deformation</span> size and geometrical parameters on the effective <span class="hlt">mechanical</span> properties of these structures are investigated. It is shown that some of them are auxetic when compressed and non-auxetic when stretched. Geometrical parameters describing sinusoidal shape of ligaments strongly affect effective <span class="hlt">mechanical</span> properties of the structure. In some cases of <span class="hlt">deformation</span>, the increase of the value of amplitude of the sinusoidal shape decreases the effective Poisson’s ratio by 0.7. Therefore the influence of geometry, as well as the arrangement of ligaments allows for smart control of <span class="hlt">mechanical</span> properties of the sinusoidal ligament structure being considered. Given the large <span class="hlt">deformation</span> of the structure, both a linear elastic material model, and a hyperelastic Neo-Hookean material model are used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MMTA...46.1704G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MMTA...46.1704G"><span id="translatedtitle">Microstructures and <span class="hlt">Mechanical</span> Properties of High-Mn TRIP Steel Based on Warm <span class="hlt">Deformation</span> of Martensite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guo, Zhikai; Li, Longfei; Yang, Wangyue; Sun, Zuqing</p> <p>2015-04-01</p> <p>High-Mn TRIP steel with about 5 wt pct Mn was prepared by a thermo-<span class="hlt">mechanical</span> treatment based on warm <span class="hlt">deformation</span> of martensite and subsequent short-time annealing in the intercritical region. The microstructural evolution and the <span class="hlt">mechanical</span> properties of the used steel during such treatment were investigated. The results indicate that during warm <span class="hlt">deformation</span> of martensite in the intercritical region, the decomposition of martensite was accelerated by warm <span class="hlt">deformation</span> and the occurrence of dynamic recrystallization of ferrite led to the formation of equiaxed ferrite grains. Meanwhile, the reverse transformation of austenite was accelerated by warm <span class="hlt">deformation</span> to some extent. During subsequent annealing in the intercritical region, static recrystallization of ferrite led to the increase in the fraction of equiaxed ferrite grains, and the formation of the reversed austenite was accelerated by the addition of the <span class="hlt">deformation</span>-stored energy, while the stability of the reversed austenite was improved by the accelerated diffusions of C atoms and Mn atoms. As a whole, the <span class="hlt">mechanical</span> properties of the used steel by the thermo-<span class="hlt">mechanical</span> treatment based on warm <span class="hlt">deformation</span> of martensite and subsequent short-time annealing in the intercritical region were comparable to the steels with similar compositions subjected to intercritical annealing for hours after cold rolling of martensite.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.4083Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.4083Z"><span id="translatedtitle"><span class="hlt">Deformation</span> and stabilisation <span class="hlt">mechanisms</span> of slow rock slides in crystalline bedrock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zangerl, C.; Prager, C.</p> <p>2009-04-01</p> <p>Deep-seated rock slides are slope instabilities which are characterised by <span class="hlt">deformation</span> along one or several shear zones where most of the measured total slope displacement localizes. Generally, a high danger potential is given when rock slides fail in a rapid manner characterised by very high sliding velocities and/or when they develop into long run-out rock avalanches. However several field surveys and <span class="hlt">deformation</span> monitoring data show that numerous deep-seated rock slides do not fail in a high velocity regime. In fact, many slides creep downwards at rates of some centimetres per year or even less and do not show any evidence for non-reversible acceleration in the past or in the future. Furthermore some of these slope instabilities are actually inactive (dormant) or have even reached a stabilised final state. <span class="hlt">Deformation</span> monitoring on <span class="hlt">active</span> rock slides show that acceleration phases characterised by velocities up to meters per day can occur. The trigger for these phases can be manifold and include heavy rainfall, snow melt, water level fluctuations of reservoirs at the slope foot, changes in the slope's equilibrium state due to antecedent slow creeping processes, changes in the material behaviour within the sliding zone, erosion along the foot of the slope, etc. Whereas the role of these triggers in promoting phases of acceleration are generally understood, the same can not be said regarding the kinematics and dynamic processes/<span class="hlt">mechanisms</span> by which rock slide masses re-stabilise once the trigger impetus has been removed. In the context of this study the term "stabilisation" is used for rock slides which decelerate from high velocities to slow base <span class="hlt">activities</span> or even stop moving after a certain amount of displacement. Given that reliable rock slide forecasts require the fundamental understanding of possible slope stabilisation <span class="hlt">mechanisms</span> this study focuses on field-based and numerically obtained key-properties which influence the long-term slope <span class="hlt">deformation</span> behaviour</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160006095','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160006095"><span id="translatedtitle">Representing Matrix Cracks Through Decomposition of the <span class="hlt">Deformation</span> Gradient Tensor in Continuum Damage <span class="hlt">Mechanics</span> Methods</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Leone, Frank A., Jr.</p> <p>2015-01-01</p> <p>A method is presented to represent the large-<span class="hlt">deformation</span> kinematics of intraply matrix cracks and delaminations in continuum damage <span class="hlt">mechanics</span> (CDM) constitutive material models. The method involves the additive decomposition of the <span class="hlt">deformation</span> gradient tensor into 'crack' and 'bulk material' components. The response of the intact bulk material is represented by a reduced <span class="hlt">deformation</span> gradient tensor, and the opening of an embedded cohesive interface is represented by a normalized cohesive displacement-jump vector. The rotation of the embedded interface is tracked as the material <span class="hlt">deforms</span> and as the crack opens. The distribution of the total local <span class="hlt">deformation</span> between the bulk material and the cohesive interface components is determined by minimizing the difference between the cohesive stress and the bulk material stress projected onto the cohesive interface. The improvements to the accuracy of CDM models that incorporate the presented method over existing approaches are demonstrated for a single element subjected to simple shear <span class="hlt">deformation</span> and for a finite element model of a unidirectional open-hole tension specimen. The material model is implemented as a VUMAT user subroutine for the Abaqus/Explicit finite element software. The presented <span class="hlt">deformation</span> gradient decomposition method reduces the artificial load transfer across matrix cracks subjected to large shearing <span class="hlt">deformations</span>, and avoids the spurious secondary failure modes that often occur in analyses based on conventional progressive damage models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApSS..371..407Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApSS..371..407Z"><span id="translatedtitle">Detailed analysis of surface asperity <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in diffusion bonding of steel hollow structural components</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, C.; Li, H.; Li, M. Q.</p> <p>2016-05-01</p> <p>This study focused on the detailed analysis of surface asperity <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in similar diffusion bonding as well as on the fabrication of high quality martensitic stainless steel hollow structural components. A special surface with regular patterns was processed to be joined so as to observe the extent of surface asperity <span class="hlt">deformation</span> under different bonding pressures. Results showed that an undamaged hollow structural component has been obtained with full interfacial contact and the same shear strength to that of base material. Fracture surface characteristic combined with surface roughness profiles distinctly revealed the enhanced surface asperity <span class="hlt">deformation</span> as the applied pressure increases. The influence of surface asperity <span class="hlt">deformation</span> <span class="hlt">mechanism</span> on joint formation was analyzed: (a) surface asperity <span class="hlt">deformation</span> not only directly expanded the interfacial contact areas, but also released <span class="hlt">deformation</span> heat and caused defects, indirectly accelerating atomic diffusion, then benefits to void shrinkage; (b) surface asperity <span class="hlt">deformation</span> readily introduced stored energy difference between two opposite sides of interface grain boundary, resulting in strain induced interface grain boundary migration. In addition, the influence of void on interface grain boundary migration was analyzed in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7123363','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7123363"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> adjacent to a thrust fault, Sangre de Cristo Mountains, Colorado</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kelly, J.C.; McConnell, D.A.; Friberg, V.M. . Dept. of Geology)</p> <p>1994-04-01</p> <p>The purpose of this study is to examine the character of grain-scale <span class="hlt">deformation</span> adjacent to a Laramide thrust fault in the Sangre de Cristo Mountains. This site represents a window through the hanging wall of a thrust sheet which juxtaposes Precambrian rocks over Pennsylvanian rocks. It provides a rare opportunity to examine <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in the footwall of a basement-involved thrust. Brittle <span class="hlt">deformation</span> is evident at both outcrop and grain-scale. Filled fractures and slickensides composed of quartz and epidote are present throughout the area, and increase in abundance adjacent to the fault zone, as does the frequency of mesoscopic faulting. Variations in <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> can be seen between the Precambrian rocks of the thrust sheet and the Pennsylvanian metasedimentary rocks, and between the metamorphosed arkoses and metapelites within the Pennsylvanian section. Cataclastic textures are present in <span class="hlt">deformed</span> Precambrian rocks, and the degree of cataclasis is greatest immediately adjacent to the fault zone. <span class="hlt">Deformation</span> in the Pennsylvanian rocks is largely dependent upon the abundance of fine-grained matrix within each sample. The degree of brittle <span class="hlt">deformation</span> is negatively correlated to the percentage of matrix. Coarser-grained sections show microscopic faults which offset quartz and feldspar grains. Offsets decrease on the faults as they pass from coarse grains into the matrix.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26866939','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26866939"><span id="translatedtitle">Large <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span>, Plasticity, and Failure of an Individual Collagen Fibril With Different Mineral Content.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J; Buehler, Markus J</p> <p>2016-02-01</p> <p>Mineralized collagen fibrils are composed of tropocollagen molecules and mineral crystals derived from hydroxyapatite to form a composite material that combines optimal properties of both constituents and exhibits incredible strength and toughness. Their complex hierarchical structure allows collagen fibrils to sustain large <span class="hlt">deformation</span> without breaking. In this study, we report a mesoscale model of a single mineralized collagen fibril using a bottom-up approach. By conserving the three-dimensional structure and the entanglement of the molecules, we were able to construct finite-size fibril models that allowed us to explore the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> which govern their <span class="hlt">mechanical</span> behavior under large <span class="hlt">deformation</span>. We investigated the tensile behavior of a single collagen fibril with various intrafibrillar mineral content and found that a mineralized collagen fibril can present up to five different <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> to dissipate energy. These <span class="hlt">mechanisms</span> include molecular uncoiling, molecular stretching, mineral/collagen sliding, molecular slippage, and crystal dissociation. By multiplying its sources of energy dissipation and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, a collagen fibril can reach impressive strength and toughness. Adding mineral into the collagen fibril can increase its strength up to 10 times and its toughness up to 35 times. Combining crosslinks with mineral makes the fibril stiffer but more brittle. We also found that a mineralized fibril reaches its maximum toughness to density and strength to density ratios for a mineral density of around 30%. This result, in good agreement with experimental observations, attests that bone tissue is optimized <span class="hlt">mechanically</span> to remain lightweight but maintain strength and toughness. PMID:26866939</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMEP...23.1954J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMEP...23.1954J"><span id="translatedtitle">Effect of High-Temperature Severe Plastic <span class="hlt">Deformation</span> on Microstructure and <span class="hlt">Mechanical</span> Properties of IF Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jindal, Vikas; Rupa, P. K. P.; Mandal, G. K.; Srivastava, V. C.</p> <p>2014-06-01</p> <p>Extensive research work has been carried out on interstitial-free steel to understand its response to <span class="hlt">deformation</span>; particularly, the behavior during severe plastic <span class="hlt">deformation</span> (SPD). However, most of these studies were mainly undertaken in the ferritic regime. The present investigation reports the initial results of our attempt to employ accumulative roll bonding (ARB), one of the variants of SPD, at a high temperature (950 °C). A considerable grain refinement has been observed, which may be attributed to the severity of <span class="hlt">deformation</span> and recrystallisation at high temperatures. Nanoindentation tests have been performed at various stages of ARB process to understand the evolution of <span class="hlt">mechanical</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.9327B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.9327B"><span id="translatedtitle">Effects of microstructure and temperature on the plastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of synthetic halite : a micromechanical approach</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bourcier, M.; Dimanov, A.; Héripré, E.; Bornert, M.; Raphanel, J.</p> <p>2012-04-01</p> <p>Halite is a rock forming mineral with geotechnical applications for storage in underground caverns (hydrocarbons, compressed air, wastes...). Halite is also a convenient analog polycristalline material, used to study <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> (crystal plasticity, recrystallization, pressure solution ...). In this work we present an investigation of intragranular plastic <span class="hlt">deformation</span> and grain boundary sliding in pure synthetic NaCl polycrystals produced by hot isostatic pressing. Uniaxial compression tests are performed in a Scanning Electron Microscope (SEM) at two temperatures, 20°C and 400 °C, on cm - sized samples. The displacement rate is kept constant at 1µm/s and the maximum axial strain is between 5 and 10 %. The surface of the samples is marked by gold micro-spheres and analyzed by 2D digital image correlation (DIC) using the CorrelManuV software, which provides full field measures of surface displacements and strains. The dominant <span class="hlt">mechanism</span> is intracrystalline plasticity, as revealed by the direct observation of slip lines and by DIC results showing intragranular <span class="hlt">deformation</span> bands. Using crystal orientation mapping, the latter are related to the traces of crystallographic slip planes. However, limited grain boundary sliding (GBS) also occurs, as a secondary but necessary <span class="hlt">mechanism</span> for accommodation of local strain incompatibilities. The relative contribution of each <span class="hlt">mechanism</span> clearly depends on the microstructure, i.e. grain size and grain size distribution. At room temperature the strain is more heterogeneous than at high temperature, at both the aggregate scale and within individual grains, where the local <span class="hlt">activity</span> of slip systems strongly depends on the relative crystalline and interfacial orientations. In particular, the easy glide planes ({110} planes) are not the only <span class="hlt">active</span> ones. In some instance, wavy slip bands clearly indicate cross slip. The above kinematic analysis should be complemented by the knowledge of the local stress states in order to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120001242','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120001242"><span id="translatedtitle">Correcting Thermal <span class="hlt">Deformations</span> in an <span class="hlt">Active</span> Composite Reflector</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bradford, Samuel C.; Agnes, Gregory S.; Wilkie, William K.</p> <p>2011-01-01</p> <p>Large, high-precision composite reflectors for future space missions are costly to manufacture, and heavy. An <span class="hlt">active</span> composite reflector capable of adjusting shape in situ to maintain required tolerances can be lighter and cheaper to manufacture. An <span class="hlt">active</span> composite reflector testbed was developed that uses an array of piezoelectric composite actuators embedded in the back face sheet of a 0.8-m reflector panel. Each individually addressable actuator can be commanded from 500 to +1,500 V, and the flatness of the panel can be controlled to tolerances of 100 nm. Measuring the surface flatness at this resolution required the use of a speckle holography interferometer system in the Precision Environmental Test Enclosure (PETE) at JPL. The existing testbed combines the PETE for test environment stability, the speckle holography system for measuring out-of-plane <span class="hlt">deformations</span>, the <span class="hlt">active</span> panel including an array of individually addressable actuators, a FLIR thermal camera to measure thermal profiles across the reflector, and a heat source. Use of an array of flat piezoelectric actuators to correct thermal <span class="hlt">deformations</span> is a promising new application for these actuators, as is the use of this actuator technology for surface flatness and wavefront control. An isogrid of these actuators is moving one step closer to a fully <span class="hlt">active</span> face sheet, with the significant advantage of ease in manufacturing. No extensive rib structure or other actuation backing structure is required, as these actuators can be applied directly to an easy-to-manufacture flat surface. Any mission with a surface flatness requirement for a panel or reflector structure could adopt this actuator array concept to create lighter structures and enable improved performance on orbit. The thermal environment on orbit tends to include variations in temperature during shadowing or changes in angle. Because of this, a purely passive system is not an effective way to maintain flatness at the scale of microns over several</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......200P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......200P"><span id="translatedtitle">Predictive Model for Temperature-Induced <span class="hlt">Deformation</span> of Robot <span class="hlt">Mechanical</span> Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poonyapak, Pranchalee</p> <p></p> <p>The positioning accuracy and repeatability of a robot are critical for many industrial applications. Drift in repeatability can occur with changes in environmental and internal conditions, such as those seen with temperature-induced <span class="hlt">deformation</span>. Thermal instability causes dimensional <span class="hlt">deformation</span>, and a warm-up cycle is typically required to bring the robot to a thermally stable working condition. The elimination of warm-up cycles will ultimately enhance the positioning accuracy of the robots, their productivity, and reduce unnecessary energy consumption. The main objective of this research was to develop a robot controller algorithm that would provide, a priori, compensation for temperature-induced <span class="hlt">deformation</span> associated with warm-up in robot <span class="hlt">mechanical</span> systems. The research started at the fundamental stage of gaining insight into the thermal behaviour and corresponding temperature-induced <span class="hlt">deformation</span> of simplified, i.e., one-dimensional, robot <span class="hlt">mechanical</span> systems consisting of slender links and heat sources. The systems were studied using concomitant experimental, numerical and analytical models to provide cross-checking of the results. For the experimental model, the <span class="hlt">deformation</span> was measured by tracking the drift of a laser diode spot across a charge-coupled device (CCD) camera chip. A non-contact measurement system consisting of an infrared camera, a CCD camera and a laser diode was developed to provide high accuracy measurement for the <span class="hlt">deformation</span>. The numerical model was generated with a coupled thermal-<span class="hlt">mechanical</span> finite element analysis incorporating thermal effects due to conduction and convection. The models were tested with the analytical model that was further extended using a finite difference technique. Once the three models showed excellent agreement, it was possible to develop a controller algorithm. <span class="hlt">Deformations</span> predicted by the finite difference model were used as input for a validation experiment of the compensation algorithm. Results of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4179130','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4179130"><span id="translatedtitle">Micro-to-nano-scale <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a bimodal ultrafine eutectic composite</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lee, Seoung Wan; Kim, Jeong Tae; Hong, Sung Hwan; Park, Hae Jin; Park, Jun-Young; Lee, Nae Sung; Seo, Yongho; Suh, Jin Yoo; Eckert, Jürgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem</p> <p>2014-01-01</p> <p>The outstading <span class="hlt">mechanical</span> properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled <span class="hlt">deformation</span> modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent <span class="hlt">mechanical</span> properties. PMID:25265897</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750007062','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750007062"><span id="translatedtitle">The surface geometry of inherited joint and fracture trace patterns resulting from <span class="hlt">active</span> and passive <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Podwysocki, M. H.; Gold, D. P.</p> <p>1974-01-01</p> <p>Hypothetical models are considered for detecting subsurface structure from the fracture or joint pattern, which may be influenced by the structure and propagated to the surface. Various patterns of an initially orthogonal fracture grid are modeled according to <span class="hlt">active</span> and passive <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. In the <span class="hlt">active</span> periclinal structure with a vertical axis, fracture frequency increased both over the dome and basin, and remained constant with decreasing depth to the structure. For passive periclinal features such as a reef or sand body, fracture frequency is determined by the arc of curvature and showed a reduction over the reefmound and increased over the basin.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4897707','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4897707"><span id="translatedtitle">Cell <span class="hlt">Deformation</span> by Single-beam Acoustic Trapping: A Promising Tool for Measurements of Cell <span class="hlt">Mechanics</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hwang, Jae Youn; Kim, Jihun; Park, Jin Man; Lee, Changyang; Jung, Hayong; Lee, Jungwoo; Shung, K. Kirk</p> <p>2016-01-01</p> <p>We demonstrate a noncontact single-beam acoustic trapping method for the quantification of the <span class="hlt">mechanical</span> properties of a single suspended cell with label-free. Experimentally results show that the single-beam acoustic trapping force results in morphological <span class="hlt">deformation</span> of a trapped cell. While a cancer cell was trapped in an acoustic beam focus, the morphological changes of the immobilized cell were monitored using bright-field imaging. The cell <span class="hlt">deformability</span> was then compared with that of a trapped polystyrene microbead as a function of the applied acoustic pressure for a better understanding of the relationship between the pressure and degree of cell <span class="hlt">deformation</span>. Cell <span class="hlt">deformation</span> was found to become more pronounced as higher pressure levels were applied. Furthermore, to determine if this acoustic trapping method can be exploited in quantifying the cell <span class="hlt">mechanics</span> in a suspension and in a non-contact manner, the <span class="hlt">deformability</span> levels of breast cancer cells with different degrees of invasiveness due to acoustic trapping were compared. It was found that highly-invasive breast cancer cells exhibited greater <span class="hlt">deformability</span> than weakly-invasive breast cancer cells. These results clearly demonstrate that the single-beam acoustic trapping technique is a promising tool for non-contact quantitative assessments of the <span class="hlt">mechanical</span> properties of single cells in suspensions with label-free. PMID:27273365</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NatSR...627238H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NatSR...627238H&link_type=ABSTRACT"><span id="translatedtitle">Cell <span class="hlt">Deformation</span> by Single-beam Acoustic Trapping: A Promising Tool for Measurements of Cell <span class="hlt">Mechanics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hwang, Jae Youn; Kim, Jihun; Park, Jin Man; Lee, Changyang; Jung, Hayong; Lee, Jungwoo; Shung, K. Kirk</p> <p>2016-06-01</p> <p>We demonstrate a noncontact single-beam acoustic trapping method for the quantification of the <span class="hlt">mechanical</span> properties of a single suspended cell with label-free. Experimentally results show that the single-beam acoustic trapping force results in morphological <span class="hlt">deformation</span> of a trapped cell. While a cancer cell was trapped in an acoustic beam focus, the morphological changes of the immobilized cell were monitored using bright-field imaging. The cell <span class="hlt">deformability</span> was then compared with that of a trapped polystyrene microbead as a function of the applied acoustic pressure for a better understanding of the relationship between the pressure and degree of cell <span class="hlt">deformation</span>. Cell <span class="hlt">deformation</span> was found to become more pronounced as higher pressure levels were applied. Furthermore, to determine if this acoustic trapping method can be exploited in quantifying the cell <span class="hlt">mechanics</span> in a suspension and in a non-contact manner, the <span class="hlt">deformability</span> levels of breast cancer cells with different degrees of invasiveness due to acoustic trapping were compared. It was found that highly-invasive breast cancer cells exhibited greater <span class="hlt">deformability</span> than weakly-invasive breast cancer cells. These results clearly demonstrate that the single-beam acoustic trapping technique is a promising tool for non-contact quantitative assessments of the <span class="hlt">mechanical</span> properties of single cells in suspensions with label-free.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27273365','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27273365"><span id="translatedtitle">Cell <span class="hlt">Deformation</span> by Single-beam Acoustic Trapping: A Promising Tool for Measurements of Cell <span class="hlt">Mechanics</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hwang, Jae Youn; Kim, Jihun; Park, Jin Man; Lee, Changyang; Jung, Hayong; Lee, Jungwoo; Shung, K Kirk</p> <p>2016-01-01</p> <p>We demonstrate a noncontact single-beam acoustic trapping method for the quantification of the <span class="hlt">mechanical</span> properties of a single suspended cell with label-free. Experimentally results show that the single-beam acoustic trapping force results in morphological <span class="hlt">deformation</span> of a trapped cell. While a cancer cell was trapped in an acoustic beam focus, the morphological changes of the immobilized cell were monitored using bright-field imaging. The cell <span class="hlt">deformability</span> was then compared with that of a trapped polystyrene microbead as a function of the applied acoustic pressure for a better understanding of the relationship between the pressure and degree of cell <span class="hlt">deformation</span>. Cell <span class="hlt">deformation</span> was found to become more pronounced as higher pressure levels were applied. Furthermore, to determine if this acoustic trapping method can be exploited in quantifying the cell <span class="hlt">mechanics</span> in a suspension and in a non-contact manner, the <span class="hlt">deformability</span> levels of breast cancer cells with different degrees of invasiveness due to acoustic trapping were compared. It was found that highly-invasive breast cancer cells exhibited greater <span class="hlt">deformability</span> than weakly-invasive breast cancer cells. These results clearly demonstrate that the single-beam acoustic trapping technique is a promising tool for non-contact quantitative assessments of the <span class="hlt">mechanical</span> properties of single cells in suspensions with label-free. PMID:27273365</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4923732','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4923732"><span id="translatedtitle">μCT based assessment of <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of designed PTMC scaffolds</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Narra, Nathaniel; Blanquer, Sébastien B.G.; Haimi, Suvi P.; Grijpma, Dirk W.; Hyttinen, Jari</p> <p>2015-01-01</p> <p>Abstract BACKGROUND: Advances in rapid-prototyping and 3D printing technologies have enhanced the possibilities in preparing designed architectures for tissue engineering applications. A major advantage in custom designing is the ability to create structures with desired <span class="hlt">mechanical</span> properties. While the behaviour of a designed scaffold can be simulated using bulk material properties, it is important to verify the behaviour of a printed scaffold at the microstructure level. OBJECTIVE: In this study we present an effective method in validating the <span class="hlt">mechanical</span> behaviour of designed scaffolds using a μCT with an in-situ <span class="hlt">mechanical</span> <span class="hlt">deformation</span> device. METHODS: The scaffolds were prepared from biodegradable poly(trimethylene carbonate) (PTMC) by stereolithography and images obtained using a high-resolution μCT with 12.25μm isometric voxels. The data was processed (filtering, segmentation) and analysed (surface generation, registration) to extract relevant <span class="hlt">deformation</span> features. RESULTS: The computed local <span class="hlt">deformation</span> fields, calculated at sub-pore resolutions, displayed expected linear behaviour within the scaffold along the compressions axis. On planes perpendicular to this axis, the <span class="hlt">deformations</span> varied by 150– 200μm. CONCLUSIONS: μCT based imaging with in-situ <span class="hlt">deformation</span> provides a vital tool in validating the design parameters of printed scaffolds. <span class="hlt">Deformation</span> fields obtained from micro-tomographic image volumes can serve to corroborate the simulated ideal design with the realized product. PMID:25818150</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930006212','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930006212"><span id="translatedtitle">Inelastic <span class="hlt">deformation</span> of metal matrix composites: Plasticity and damage <span class="hlt">mechanisms</span>, part 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Majumdar, B. S.; Newaz, G. M.</p> <p>1992-01-01</p> <p>The inelastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> for the SiC (SCS-6)/Ti-15-3 system were studied at 538 C (1000 F) using a combination of <span class="hlt">mechanical</span> measurements and detailed microstructural examinations. The objectives were to evaluate the contributions of plasticity and damage to the overall MMC response, and to compare the room temperature and elevated temperature <span class="hlt">deformation</span> behaviors. Four different laminates were studied: (0)8, (90)8,(+ or -45)2s, and (0/90)2s, with the primary emphasis on the unidirectional (0)8, and (90)8 systems. The elevated temperature responses were similar to those at room temperature, involving a two-stage elastic-plastic type of response for the (0)8 system, and a characteristic three-stage <span class="hlt">deformation</span> response for the (90)8 and (+ or -45)2s systems. The primary effects of elevated temperatures included: (1) reduction in the 'yield' and failure strengths; (2) plasticity through diffused slip rather than concentrated planar slip (which occurred at room temperature); and (3) time-dependent <span class="hlt">deformation</span>. The inelastic <span class="hlt">deformation</span> <span class="hlt">mechanism</span> for the (0)8 MMC was dominated by plasticity at both temperatures. For the (90)8 and (+ or -45)2s MMCs, a combination of damage and plasticity contributed to the <span class="hlt">deformation</span> at both temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhLA..380.2849M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016PhLA..380.2849M&link_type=ABSTRACT"><span id="translatedtitle">Investigation of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of staggered nanocomposites using molecular dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mathiazhagan, S.; Anup, S.</p> <p>2016-08-01</p> <p>Biological materials with nanostructure of regularly or stair-wise staggered arrangements of hard platelets reinforced in a soft protein matrix have superior <span class="hlt">mechanical</span> properties. Applications of these nanostructures to ceramic matrix composites could enhance their toughness. Using molecular dynamics simulations, <span class="hlt">mechanical</span> behaviour of the bio-inspired nanocomposites is studied. Regularly staggered model shows better flow behaviour compared to stair-wise staggered model due to the symmetrical crack propagation along the interface. Though higher stiffness and strength are obtained for stair-wise staggered models, rapid crack propagation reduces the toughness. Arresting this crack propagation could lead to superior <span class="hlt">mechanical</span> properties in stair-wise staggered models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920013041','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920013041"><span id="translatedtitle">Inelastic <span class="hlt">Deformation</span> of Metal Matrix Composites. Part 1; Plasticity and Damage <span class="hlt">Mechanisms</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Majumdar, B. S.; Newaz, G. M.</p> <p>1992-01-01</p> <p>The <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a Ti 15-3/SCS6 (SiC fiber) metal matrix composite (MMC) were investigated using a combination of <span class="hlt">mechanical</span> measurements and microstructural analysis. The objectives were to evaluate the contributions of plasticity and damage to the overall inelastic response, and to confirm the <span class="hlt">mechanisms</span> by rigorous microstructural evaluations. The results of room temperature experiments performed on 0 degree and 90 degree systems primarily are reported in this report. Results of experiments performed on other laminate systems and at high temperatures will be provided in a forthcoming report. Inelastic <span class="hlt">deformation</span> of the 0 degree MMC (fibers parallel to load direction) was dominated by the plasticity of the matrix. In contrast, inelastic <span class="hlt">deformations</span> of the 90 degree composite (fibers perpendicular to loading direction) occurred by both damage and plasticity. The predictions of a continuum elastic plastic model were compared with experimental data. The model was adequate for predicting the 0 degree response; however, it was inadequate for predicting the 90 degree response largely because it neglected damage. The importance of validating constitutive models using a combination of <span class="hlt">mechanical</span> measurements and microstructural analysis is pointed out. The <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, and the likely sequence of events associated with the inelastic <span class="hlt">deformation</span> of MMCs, are indicated in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT........52J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT........52J"><span id="translatedtitle"><span class="hlt">Mechanical</span> Behavior of Magnesium Experienced Severe Plastic <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jiao, Xing</p> <p></p> <p>This thesis reviewed the development of processing technologies, including forging, rolling, extrusion and equal channel angular pressing (ECAP). Among these technologies, ECAP technology to process pure magnesium was studied. This thesis describes what ECAP technology is and reviews the current research status of ECAP processed pure magnesium. This thesis studied the effects of temperature, passes and post-heat treatment on microstructures and sample hardness. Across each sample, the microstructure was observed. Experiments were conducted at 350°C, 250°C and 200°C to study the microstructure change as a function of temperature. It was found that as the temperature was decreased, the average grain size also decreased. We fixed the temperature at 200°C and used 1 pass, 2 passes, 4 passes and 8 passes to see the microstructure change right after pressing. The microstructure was altered significantly after post heat treatment. The more suitable post heat treatment for samples pressed at 200°C with 8 passes, is 300°C for 40 min with water cooling, by which we can get the smallest average grain size of 11.2 μm. The hardness was higher with more severe <span class="hlt">deformation</span>, more passes, and lower pressing temperature, which has been increased more than 20% from 7.5HV right after pressing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/571745','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/571745"><span id="translatedtitle">Tensile properties and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in two-phase titanium aluminide sheet material</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Appel, F.; Wagner, R.; Clemens, H.; Glatz, W.</p> <p>1997-12-31</p> <p>The <span class="hlt">mechanical</span> properties of two-phase TiAl sheets with different compositions and microstructures were investigated over the temperature range 25--1,000 C. The microprocesses of plasticity were characterized by electron microscope observations. Particular emphasis has been paid to the <span class="hlt">mechanisms</span> governing the <span class="hlt">deformation</span> behavior at elevated temperatures which are relevant for the fabrication and engineering applications of structural components.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009SMaS...18i5008L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009SMaS...18i5008L"><span id="translatedtitle">Characterization of micro-scale creep <span class="hlt">deformation</span> of an electro-<span class="hlt">active</span> paper actuator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Sangwoo; Kim, Joo-Hyung; Kang, Kwangseon; Kim, Jaehwan; Kim, Heung Soo; Yang, Chulho</p> <p>2009-09-01</p> <p>The creep <span class="hlt">deformation</span> process of an electro-<span class="hlt">active</span> paper (EAPap) actuator was investigated by adapting stepwise dead-weight loading. To understand the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of the EAPap film, including morphological and structural changes, various loading conditions below yield strength were applied to cellophane EAPap. From the structural observation, micro-dimples and micro-cracks were detected at applied load lower than 10% of yield strength, while they were not found in higher load conditions. It is hypothesized that only short and random fibers in the amorphous region may respond to the applied stress at the low loading condition, not the fibers in the crystalline area. As a result, <span class="hlt">deformation</span> energy at the localized spot accumulated and created micro-defects at the surface. Meanwhile, fibers in the crystalline region may sustain most of the loads as creep load increases to a high level. Molecular chains in the fiber may rotate and elongate with high load. Elongated fibers were observed only at a high level of load. From the structural change as a function of applied load, a peak shift of crystal orientation was observed only in high load conditions by wide angle x-ray measurement. This may confirm that creep <span class="hlt">deformation</span> could give rise to structure changes in EAPap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26863531','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26863531"><span id="translatedtitle">Perceiving Object Shape from Specular Highlight <span class="hlt">Deformation</span>, Boundary Contour <span class="hlt">Deformation</span>, and <span class="hlt">Active</span> Haptic Manipulation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Norman, J Farley; Phillips, Flip; Cheeseman, Jacob R; Thomason, Kelsey E; Ronning, Cecilia; Behari, Kriti; Kleinman, Kayla; Calloway, Autum B; Lamirande, Davora</p> <p>2016-01-01</p> <p>It is well known that motion facilitates the visual perception of solid object shape, particularly when surface texture or other identifiable features (e.g., corners) are present. Conventional models of structure-from-motion require the presence of texture or identifiable object features in order to recover 3-D structure. Is the facilitation in 3-D shape perception similar in magnitude when surface texture is absent? On any given trial in the current experiments, participants were presented with a single randomly-selected solid object (bell pepper or randomly-shaped "glaven") for 12 seconds and were required to indicate which of 12 (for bell peppers) or 8 (for glavens) simultaneously visible objects possessed the same shape. The initial single object's shape was defined either by boundary contours alone (i.e., presented as a silhouette), specular highlights alone, specular highlights combined with boundary contours, or texture. In addition, there was a haptic condition: in this condition, the participants haptically explored with both hands (but could not see) the initial single object for 12 seconds; they then performed the same shape-matching task used in the visual conditions. For both the visual and haptic conditions, motion (rotation in depth or <span class="hlt">active</span> object manipulation) was present in half of the trials and was not present for the remaining trials. The effect of motion was quantitatively similar for all of the visual and haptic conditions-e.g., the participants' performance in Experiment 1 was 93.5 percent higher in the motion or <span class="hlt">active</span> haptic manipulation conditions (when compared to the static conditions). The current results demonstrate that <span class="hlt">deforming</span> specular highlights or boundary contours facilitate 3-D shape perception as much as the motion of objects that possess texture. The current results also indicate that the improvement with motion that occurs for haptics is similar in magnitude to that which occurs for vision. PMID:26863531</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4749382','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4749382"><span id="translatedtitle">Perceiving Object Shape from Specular Highlight <span class="hlt">Deformation</span>, Boundary Contour <span class="hlt">Deformation</span>, and <span class="hlt">Active</span> Haptic Manipulation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Cheeseman, Jacob R.; Thomason, Kelsey E.; Ronning, Cecilia; Behari, Kriti; Kleinman, Kayla; Calloway, Autum B.; Lamirande, Davora</p> <p>2016-01-01</p> <p>It is well known that motion facilitates the visual perception of solid object shape, particularly when surface texture or other identifiable features (e.g., corners) are present. Conventional models of structure-from-motion require the presence of texture or identifiable object features in order to recover 3-D structure. Is the facilitation in 3-D shape perception similar in magnitude when surface texture is absent? On any given trial in the current experiments, participants were presented with a single randomly-selected solid object (bell pepper or randomly-shaped “glaven”) for 12 seconds and were required to indicate which of 12 (for bell peppers) or 8 (for glavens) simultaneously visible objects possessed the same shape. The initial single object’s shape was defined either by boundary contours alone (i.e., presented as a silhouette), specular highlights alone, specular highlights combined with boundary contours, or texture. In addition, there was a haptic condition: in this condition, the participants haptically explored with both hands (but could not see) the initial single object for 12 seconds; they then performed the same shape-matching task used in the visual conditions. For both the visual and haptic conditions, motion (rotation in depth or <span class="hlt">active</span> object manipulation) was present in half of the trials and was not present for the remaining trials. The effect of motion was quantitatively similar for all of the visual and haptic conditions–e.g., the participants’ performance in Experiment 1 was 93.5 percent higher in the motion or <span class="hlt">active</span> haptic manipulation conditions (when compared to the static conditions). The current results demonstrate that <span class="hlt">deforming</span> specular highlights or boundary contours facilitate 3-D shape perception as much as the motion of objects that possess texture. The current results also indicate that the improvement with motion that occurs for haptics is similar in magnitude to that which occurs for vision. PMID:26863531</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22399254','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22399254"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> study of a hot rolled Zr-2.5Nb alloy by transmission electron microscopy. II. In situ transmission electron microscopy study of <span class="hlt">deformation</span> <span class="hlt">mechanism</span> change of a Zr-2.5Nb alloy upon heavy ion irradiation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Long, Fei; Daymond, Mark R. Yao, Zhongwen; Kirk, Marquis A.</p> <p>2015-03-14</p> <p>The effect of heavy-ion irradiation on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a Zr-2.5Nb alloy was investigated by using the in situ transmission electron microscopy <span class="hlt">deformation</span> technique. The gliding behavior of prismatic 〈a〉 dislocations has been dynamically observed before and after irradiation at room temperature and 300 °C. Irradiation induced loops were shown to strongly pin the gliding dislocations. Unpinning occurred while loops were incorporated into or eliminated by 〈a〉 dislocations. In the irradiated sample, loop depleted areas with a boundary parallel to the basal plane trace were found by post-mortem observation after room temperature <span class="hlt">deformation</span>, supporting the possibility of basal channel formation in bulk neutron irradiated samples. Strong <span class="hlt">activity</span> of pyramidal slip was also observed at both temperatures, which might be another important <span class="hlt">mechanism</span> to induce plastic instability in irradiated zirconium alloys. Finally, (011{sup ¯}1)〈01{sup ¯}12〉 twinning was identified in the irradiated sample <span class="hlt">deformed</span> at 300 °C.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JAP...117j4302L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JAP...117j4302L&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> study of a hot rolled Zr-2.5Nb alloy by transmission electron microscopy. II. In situ transmission electron microscopy study of <span class="hlt">deformation</span> <span class="hlt">mechanism</span> change of a Zr-2.5Nb alloy upon heavy ion irradiation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Long, Fei; Daymond, Mark R.; Yao, Zhongwen; Kirk, Marquis A.</p> <p>2015-03-01</p> <p>The effect of heavy-ion irradiation on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a Zr-2.5Nb alloy was investigated by using the in situ transmission electron microscopy <span class="hlt">deformation</span> technique. The gliding behavior of prismatic <a> dislocations has been dynamically observed before and after irradiation at room temperature and 300 °C. Irradiation induced loops were shown to strongly pin the gliding dislocations. Unpinning occurred while loops were incorporated into or eliminated by <a> dislocations. In the irradiated sample, loop depleted areas with a boundary parallel to the basal plane trace were found by post-mortem observation after room temperature <span class="hlt">deformation</span>, supporting the possibility of basal channel formation in bulk neutron irradiated samples. Strong <span class="hlt">activity</span> of pyramidal slip was also observed at both temperatures, which might be another important <span class="hlt">mechanism</span> to induce plastic instability in irradiated zirconium alloys. Finally, {01 1 ¯ 1 }⟨0 1 ¯ 12 ⟩ twinning was identified in the irradiated sample <span class="hlt">deformed</span> at 300 °C.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22476011','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22476011"><span id="translatedtitle">Investigation of <span class="hlt">deformation</span> micro-<span class="hlt">mechanisms</span> in nickel consolidated from a bimodal powder by spark plasma sintering</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tingaud, D.; Jenei, P.; Krawczynska, A.; Mompiou, F.; Gubicza, J.; Dirras, G.</p> <p>2015-01-15</p> <p>Bulk polycrystalline nickel compact was processed by spark plasma sintering from heterogeneous powder consisting of a mixture of nanometer and micrometer sized particles. The consolidated samples inherited the bimodal structure of the starting powder and was composed of ~ 55 vol.% coarse-grained (with the grain size larger than 1 μm) and ~ 45 vol.% ultrafine-grained (with an average grain size of ~ 550 nm) components. The <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> were established by EBSD, X-ray line profile analysis and in-situ TEM observations. In the ultrafine-grained volume, the <span class="hlt">deformation</span> occurred mainly through the <span class="hlt">activation</span> of dislocation sources emitting full or partial dislocation either from grain interior or grain boundaries. Besides dislocation <span class="hlt">activity</span>, rolling and sliding of nanograins were also observed during <span class="hlt">deformation</span> by in-situ transmission electron microscopy, which have a considerable contribution to the observed high strain rate sensitivity of the bimodal microstructure. The cracks formed during <span class="hlt">deformation</span> easily propagated in the nanograin regions due to the weaker particle bonding caused by the relatively high fraction of native oxide layer on the surface of the initial nanoparticles. - Highlights: • Bulk bimodal polycrystalline Ni was processed by SPS from a heterogeneous powder. • High SRS of the flow stress was observed which enhanced ductility and strength. • In-situ TEM revealed dislocation sources inside and at the boundaries of UFGs. • Twinning, partial dislocation and NG rolling were observed at crack tip vicinity. • The high SRS pertained to both dislocation <span class="hlt">activity</span> in CG and NG rolling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1615065H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1615065H"><span id="translatedtitle">Understanding creep in sandstone reservoirs - theoretical <span class="hlt">deformation</span> <span class="hlt">mechanism</span> maps for pressure solution in granular materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hangx, Suzanne; Spiers, Christopher</p> <p>2014-05-01</p> <p>Subsurface exploitation of the Earth's natural resources removes the natural system from its chemical and physical equilibrium. As such, groundwater extraction and hydrocarbon production from subsurface reservoirs frequently causes surface subsidence and induces (micro)seismicity. These effects are not only a problem in onshore (e.g. Groningen, the Netherlands) and offshore hydrocarbon fields (e.g. Ekofisk, Norway), but also in urban areas with extensive groundwater pumping (e.g. Venice, Italy). It is known that fluid extraction inevitably leads to (poro)elastic compaction of reservoirs, hence subsidence and occasional fault reactivation, and causes significant technical, economic and ecological impact. However, such effects often exceed what is expected from purely elastic reservoir behaviour and may continue long after exploitation has ceased. This is most likely due to time-dependent compaction, or 'creep <span class="hlt">deformation</span>', of such reservoirs, driven by the reduction in pore fluid pressure compared with the rock overburden. Given the societal and ecological impact of surface subsidence, as well as the current interest in developing geothermal energy and unconventional gas resources in densely populated areas, there is much need for obtaining better quantitative understanding of creep in sediments to improve the predictability of the impact of geo-energy and groundwater production. The key problem in developing a reliable, quantitative description of the creep behaviour of sediments, such as sands and sandstones, is that the operative <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are poorly known and poorly quantified. While grain-scale brittle fracturing plus intergranular sliding play an important role in the early stages of compaction, these time-independent, brittle-frictional processes give way to compaction creep on longer time-scales. Thermally-<span class="hlt">activated</span> mass transfer processes, like pressure solution, can cause creep via dissolution of material at stressed grain contacts, grain</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012M%26PS...47..120T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012M%26PS...47..120T"><span id="translatedtitle">Resolution of impact-related microstructures in lunar zircon: A shock-<span class="hlt">deformation</span> <span class="hlt">mechanism</span> map</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Timms, Nicholas E.; Reddy, Steven M.; Healy, David; Nemchin, Alexander A.; Grange, Marion L.; Pidgeon, Robert T.; Hart, Robert</p> <p>2012-01-01</p> <p>The microstructures of lunar zircon grains from breccia samples 72215, 73215, 73235, and 76295 collected during the Apollo 17 mission have been characterized via optical microscopy, cathodoluminescence imaging, and electron backscatter diffraction mapping. These zircon grains preserve <span class="hlt">deformation</span> microstructures that show a wide range in style and complexity. Planar <span class="hlt">deformation</span> features (PDFs) are documented in lunar zircon for the first time, and occur along {001}, {110}, and {112}, typically with 0.1-25 μm spacing. The widest PDFs associated with {112} contain microtwin lamellae with 65°/<110> misorientation relationships. <span class="hlt">Deformation</span> bands parallel to {100} planes and irregular low-angle (<10°) boundaries most commonly have <001> misorientation axes. This geometry is consistent with a dislocation glide system with <100>{010} during dislocation creep. Nonplanar fractures, recrystallized domains with sharp, irregular interfaces, and localized annealing textures along fractures are also observed. No occurrences of reidite were detected. Shock-<span class="hlt">deformation</span> microstructures in zircon are explained in terms of elastic anisotropy of zircon. PDFs form along a limited number of specific {hkl} planes that are perpendicular to directions of high Young's modulus, suggesting that PDFs are likely to be planes of longitudinal lattice damage. Twinned {112} PDFs also contain directions of high shear modulus. A conceptual model is proposed for the development of different <span class="hlt">deformation</span> microstructures during an impact event. This “shock-<span class="hlt">deformation</span> <span class="hlt">mechanism</span> map” is used to explain the relative timing, conditions, and complexity relationships between impact-related <span class="hlt">deformation</span> microstructures in zircon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26652360','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26652360"><span id="translatedtitle">Molecular <span class="hlt">mechanisms</span> in <span class="hlt">deformation</span> of cross-linked hydrogel nanocomposite.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mathesan, Santhosh; Rath, Amrita; Ghosh, Pijush</p> <p>2016-02-01</p> <p>The self-folding behavior in response to external stimuli observed in hydrogels is potentially used in biomedical applications. However, the use of hydrogels is limited because of its reduced <span class="hlt">mechanical</span> properties. These properties are enhanced when the hydrogels are cross-linked and reinforced with nanoparticles. In this work, molecular dynamics (MD) simulation is applied to perform uniaxial tension and pull out tests to understand the <span class="hlt">mechanism</span> contributing towards the enhanced <span class="hlt">mechanical</span> properties. Also, nanomechanical characterization is performed using quasi static nanoindentation experiments to determine the Young's modulus of hydrogels in the presence of nanoparticles. The stress-strain responses for chitosan (CS), chitosan reinforced with hydroxyapatite (HAP) and cross-linked chitosan are obtained from uniaxial tension test. It is observed that the Young's modulus and maximum stress increase as the HAP content increases and also with cross-linking process. Load displacement plot from pullout test is compared for uncross-linked and cross-linked chitosan chains on hydroxyapatite surface. MD simulation reveals that the variation in the dihedral conformation of chitosan chains and the evolution of internal structural variables are associated with <span class="hlt">mechanical</span> properties. Additional results reveal that the formation of hydrogen bonds and electrostatic interactions is responsible for the above variations in different systems. PMID:26652360</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26737734','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26737734"><span id="translatedtitle">Tuning of a <span class="hlt">deformable</span> image registration procedure for skin component <span class="hlt">mechanical</span> properties assessment.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Montin, E; Cutri, E; Spadola, G; Testori, A; Pennati, G; Mainardi, L</p> <p>2015-01-01</p> <p>Several studies report the <span class="hlt">mechanical</span> properties of skin tissues but their values largely depend on the measurement method. Therefore, we investigated the feasibility of recognizing the cellular constituents <span class="hlt">mechanical</span> properties of pigmented skin by Confocal Laser Scanner Microscopy (CLSM). With this purpose, an healthy volunteer was examined in three areas nearby a pigmented skin lesion in two configurations: <span class="hlt">deforming</span> and non <span class="hlt">deforming</span> the nevus. The tissue displacement of the nevus was then assessed by means of <span class="hlt">deformable</span> registration of the images in these two configurations. There are several registration strategy able to overcome this task, among them, we proposed two methods with different <span class="hlt">deformation</span> models: a Free Form <span class="hlt">Deformation</span> (FFD) model based on b-spline and a second one based on Demons Registration Algorithm (DRA). These two strategies need the definition of several parameters in order to obtain optimal registration performances. Thus, we tuned these parameters by means of simulated data and evaluated their registration abilities on the real in vivo CLSM acquisitions in the two configurations. The results showed that the registration using DRA had a better performance in comparison to the FFD one, in particular in two out of the three areas the DRA performance was significantly better than the FFD one. The registration procedure highlighted <span class="hlt">deformation</span> differences among the chosen areas. PMID:26737734</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/989713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/989713"><span id="translatedtitle">A TEM Study of Creep <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Allvac 718Plus</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Unocic, Raymond R; Unocic, Kinga A; Hayes, Robert; Daehn, Glenn; Mills, Michael J.</p> <p>2010-01-01</p> <p>A preliminary study on the evolution of creep <span class="hlt">deformation</span> substructure in Ni-base superalloy Allvac 718Plus has been performed. Specimens crept at 620 MPa and at temperatures ranging from 690-732 C were examined utilizing diffraction contrast TEM characterization techniques. Creep was interrupted at 1-2.5% strain in order to study the <span class="hlt">deformation</span> substructure following a limited amount of <span class="hlt">deformation</span>. The dominant <span class="hlt">deformation</span> modes at each of the test temperatures were highly planar in nature and involved shearing of the matrix and precipitates on {111} glide planes. In addition, paired a/2<110> dislocations were evident which suggest an antiphase boundary shearing <span class="hlt">mechanism</span>. Creep induced microtwinning was also observed at the highest creep temperature which was created by identical a/6<112> Shockley partial dislocations that shear the matrix and precipitates on consecutive close packed {111} glide planes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/405610','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/405610"><span id="translatedtitle">Geotechnical factors influencing a time-dependent <span class="hlt">deformation</span> <span class="hlt">mechanism</span> around an entry in a dipping seam</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Larson, M.K.; Maleki, H.</p> <p>1996-12-01</p> <p>The U.S. Bureau of Mines and Cyprus Shoshone Coal Corp. conducted a study of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in strata around a longwall gate road system at two sites in an underground coal mine near Hanna, WY. Of particular interest was time-dependent (on the order of several months) roof <span class="hlt">deformation</span>. Strata above and below the coal seam are very weak, carbonaceous mudstones that have cohesionless planes of weakness oriented along bedding, which dips approximately 8{degrees} to 16{degrees} at N 49{degrees} E. An extensive array of instrumented roof bolts, roof extensometers, and biaxial stressmeters were installed during development mining at these two sites under variable depth of cover [183 to 335 in (600 to 1,100 ft)], seam dip (10{degrees} to 16{degrees}), and top coal thickness [estimated to be 0.30 to 0.61 in (1 to 2 ft) on the downdip side of the entry]. Bolt load and roof <span class="hlt">deformation</span> histories during the entry development periods were compared. Bolt loads at site 2 were less than those at site 1, which is consistent with the amount of overburden. <span class="hlt">Deformation</span> magnitudes at site 2 were similar to those at site 1, but <span class="hlt">deformation</span> rates were approximately 44% greater and nearly constant over time, whereas the <span class="hlt">deformation</span> rates at site 1 decreased exponentially over time. Also, most <span class="hlt">deformation</span> occurred above the bolt horizon at site two, but extensometer measurements at site 1 showed that a significant amount of <span class="hlt">deformation</span> occurred within the bolt horizon. The most significant factor that influenced bolt tension and time-dependent strata <span class="hlt">deformation</span> was strength and Young`s modulus of the strata. Finite-difference models support this conclusion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930017046','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930017046"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of NiAl cyclicly <span class="hlt">deformed</span> near the brittle-to-ductile transition temperature</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cullers, Cheryl L.; Antolovich, Stephen D.</p> <p>1993-01-01</p> <p>The intermetallic compound NiAl is one of many advanced materials which is being scrutinized for possible use in high temperature, structural applications. Stoichiometric NiAl has a high melting temperature, excellent oxidation resistance, and good thermal conductivity. Past research has concentrated on improving monotonic properties. The encouraging results obtained on binary and micro-alloyed NiAl over the past ten years have led to the broadening of NiAl experimental programs. The purpose of this research project was to determine the low cycle fatigue properties and dislocation <span class="hlt">mechanisms</span> of stoichiometric NiAl at temperatures near the monotonic brittle-to-ductile transition. The fatigue properties were found to change only slightly in the temperature range of 600 to 700 K; a temperature range over which monotonic ductility and fracture strength increase markedly. The shape of the cyclic hardening curves coincided with the changes observed in the dislocation structures. The evolution of dislocation structures did not appear to change with temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JMEP...22.2048X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JMEP...22.2048X"><span id="translatedtitle">Creep Properties and <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> of a FGH95 Ni-based Superalloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Jun; Tian, Su-gui; Zhou, Xiao-ming</p> <p>2013-07-01</p> <p>By means of full heat treatment, microstructure observation, lattice parameters determination, and the measurement of creep curves, an investigation has been conducted into the microstructure and creep <span class="hlt">mechanisms</span> of FGH95 Ni-based superalloy. Results show that after the alloy is hot isostatically pressed, coarse γ' phase discontinuously distributes along the previous particle boundaries. After solution treatment at high temperature and aging, the grain size has no obvious change, and the amount of coarse γ' phase decreases, and a high volume fraction of fine γ' phase dispersedly precipitates in the γ matrix. Moreover, the granular carbides are found to be precipitated along grain boundaries, which can hinder the grain boundaries' sliding and enhance the creep resistance of the alloy. By x-ray diffraction analysis, it is indicated that the lattice misfit between the γ and γ' phases decreases in the alloy after full heat treatment. In the ranges of experimental temperatures and applied stresses, the creep <span class="hlt">activation</span> energy of the alloy is measured to be 630.4 kJ/mol. During creep, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of the alloy are that dislocations slip in the γ matrix or shear into the γ' phase. Thereinto, the creep dislocations move over the γ' phase by the Orowan <span class="hlt">mechanism</span>, and the < { 1 10 } rangle super-dislocation shearing into the γ' phase can be decomposed to form the configuration of (1/3) < { 1 12 } rangle super-Shockleys' partials and the stacking fault.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2000418','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2000418"><span id="translatedtitle">Finite <span class="hlt">deformation</span> <span class="hlt">mechanics</span> in buckled thin films on compliant supports</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jiang, Hanqing; Khang, Dahl-Young; Song, Jizhou; Sun, Yugang; Huang, Yonggang; Rogers, John A.</p> <p>2007-01-01</p> <p>We present detailed experimental and theoretical studies of the <span class="hlt">mechanics</span> of thin buckled films on compliant substrates. In particular, accurate measurements of the wavelengths and amplitudes in structures that consist of thin, single-crystal ribbons of silicon covalently bonded to elastomeric substrates of poly(dimethylsiloxane) reveal responses that include wavelengths that change in an approximately linear fashion with strain in the substrate, for all values of strain above the critical strain for buckling. Theoretical reexamination of this system yields analytical models that can explain these and other experimental observations at a quantitative level. We show that the resulting <span class="hlt">mechanics</span> has many features in common with that of a simple accordion bellows. These results have relevance to the many emerging applications of controlled buckling structures in stretchable electronics, microelectromechanical systems, thin-film metrology, optical devices, and others. PMID:17898178</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17898178','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17898178"><span id="translatedtitle">Finite <span class="hlt">deformation</span> <span class="hlt">mechanics</span> in buckled thin films on compliant supports.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jiang, Hanqing; Khang, Dahl-Young; Song, Jizhou; Sun, Yugang; Huang, Yonggang; Rogers, John A</p> <p>2007-10-01</p> <p>We present detailed experimental and theoretical studies of the <span class="hlt">mechanics</span> of thin buckled films on compliant substrates. In particular, accurate measurements of the wavelengths and amplitudes in structures that consist of thin, single-crystal ribbons of silicon covalently bonded to elastomeric substrates of poly(dimethylsiloxane) reveal responses that include wavelengths that change in an approximately linear fashion with strain in the substrate, for all values of strain above the critical strain for buckling. Theoretical reexamination of this system yields analytical models that can explain these and other experimental observations at a quantitative level. We show that the resulting <span class="hlt">mechanics</span> has many features in common with that of a simple accordion bellows. These results have relevance to the many emerging applications of controlled buckling structures in stretchable electronics, microelectromechanical systems, thin-film metrology, optical devices, and others. PMID:17898178</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/975747','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/975747"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> at Different grain sizes in a cryogenically ball-milled Al-Mg alloy.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Liao, Xiaozhou; Huang, J.; Zhu, Y. T.; Zhou, F.; Lavernia, Enrique J.</p> <p>2001-01-01</p> <p>An Al-7.5 wt. % Mg alloy was ball-milled in liquid N2 for eight hours and its microstructures were investigated using transmission electron microscopy. Electron diffraction confirmed that the resulting powder is a supersaturated Al-Mg solid solution with a face-centered cubic structure. Three nanostructures with different grain size ranges and shapes were observed and the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in these structures were found to be different. The reasons for the different <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> were discussed. Keywords: Aluminum alloy; Cryogenic ball milling; Transmission electron microscopy; Microstructure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004JSeis...8..439P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JSeis...8..439P"><span id="translatedtitle">Microseismicity and <span class="hlt">active</span> <span class="hlt">deformation</span> of Messinia, SW Greece</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Papoulia, J.; Makris, J.</p> <p></p> <p>By deploying a 30 3-component digital seismic array in the Messiniakos gulf and the surrounding region, we recorded for a period of 45 days the microseismic <span class="hlt">activity</span>. With a minimum of six records per event, we located 1121 earthquakes corresponding to an average of 20 events per day. For the hypocenter location we used a local velocity model adopted to two controlled source seismic experiments. Within the array, traveltime residuals were within ± 0.2 s and the epicentral accuracy in the order of ± 2 km, while the hypocentral one is twice this value. Correlation of the seismicity with the tectonic elements indicated that most of the NW-SE oriented faults are <span class="hlt">active</span> with strike-slip movement along this orientation and extension perpendicular to it. The neogene basins of Messini, Meligalas and Megalopolis are seismically very <span class="hlt">active</span> and their eastern flanks are delineated by higher seismic <span class="hlt">activity</span> than their western ones. This indicates that the basins are asymmetric with master faults defining their eastern-northeastern flanks. This hypothesis is supported by the asymmetric structure mapped at the offshore Messiniakos basin as densely spaced high resolution reflection seismic profiles have revealed. The western margins of the basins are less <span class="hlt">deformed</span> and the seismic <span class="hlt">activity</span> is dispersed over several minor NW-SE faults. Since the NW-SE striking faults onshore are truncated by major NE-SW oriented ones, their overall length is shortened, reducing their seismic potential and capacity to store large stresses that could produce events above Ms6.1. Offshore western Messinia, in the Ionian Sea, the size and <span class="hlt">activity</span> of the faults is significantly larger and prone to develop events of larger magnitudes. Subcrustal seismicity indicates a deepening of the foci to the east-northeast.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980007072','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980007072"><span id="translatedtitle">Communications: <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> of Dendrites by Fluid Flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pilling, J.; Hellawell, A.</p> <p>1996-01-01</p> <p>It is generally accepted that liquid agitation during alloy solidification assists in crystal multiplication, as in dendrite fragmentation and the detachment of side arms in the mushy region of a casting. Even without deliberate stirring by electromagnetic or <span class="hlt">mechanical</span> means, there is often vigorous interdendritic fluid flow promoted by natural thermosolutal convection. In this analysis, we shall estimate the stress at the root of a secondary dendrite arm of aluminum arising from the action of a flow of molten metal past the dendrite arm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MS%26E..118a2030F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MS%26E..118a2030F"><span id="translatedtitle">Influence of thermally <span class="hlt">activated</span> processes on the <span class="hlt">deformation</span> behavior during low temperature ECAP</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fritsch, S.; Scholze, M.; F-X Wagner, M.</p> <p>2016-03-01</p> <p>High strength aluminum alloys are generally hard to <span class="hlt">deform</span>. Therefore, the application of conventional severe plastic <span class="hlt">deformation</span> methods to generate ultrafine-grained microstructures and to further increase strength is considerably limited. In this study, we consider low temperature <span class="hlt">deformation</span> in a custom-built, cooled equal channel angular pressing (ECAP) tool (internal angle 90°) as an alternative approach to severely plastically <span class="hlt">deform</span> a 7075 aluminum alloy. To document the maximum improvement of <span class="hlt">mechanical</span> properties, these alloys are initially <span class="hlt">deformed</span> from a solid solution heat-treated condition. We characterize the <span class="hlt">mechanical</span> behavior and the microstructure of the coarse grained initial material at different low temperatures, and we analyze how a tendency for the PLC effect and the strain-hardening rate affect the formability during subsequent severe plastic <span class="hlt">deformation</span> at low temperatures. We then discuss how the <span class="hlt">deformation</span> temperature and velocity influence the occurrence of PLC effects and the homogeneity of the <span class="hlt">deformed</span> ECAP billets. Besides the <span class="hlt">mechanical</span> properties and these microstructural changes, we discuss technologically relevant processing parameters (such as pressing forces) and practical limitations, as well as changes in fracture behavior of the low temperature <span class="hlt">deformed</span> materials as a function of <span class="hlt">deformation</span> temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2813421','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2813421"><span id="translatedtitle">Emergent morphogenesis: elastic <span class="hlt">mechanics</span> of a self-<span class="hlt">deforming</span> tissue</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Davidson, Lance A.; Joshi, Sagar D.; Kim, Hye Young; von Dassow, Michelangelo; Zhang, Lin; Zhou, Jian</p> <p>2009-01-01</p> <p>Multicellular organisms are generated by coordinated cell movements during morphogenesis. Convergent extension is a key tissue movement that organizes mesoderm, ectoderm, and endoderm in vertebrate embryos. The goals of researchers studying convergent extension, and morphogenesis in general, include understanding the molecular pathways that control cell identity, establish fields of cell types, and regulate cell behaviors. Cell identity, the size and boundaries of tissues, and the behaviors exhibited by those cells shape the developing embryo; however, there is a fundamental gap between understanding the molecular pathways that control processes within single cells and understanding how cells work together to assemble multi-cellular structures. Theoretical and experimental biomechanics of embryonic tissues are increasingly being used to bridge that gap. The efforts to map molecular pathways and the <span class="hlt">mechanical</span> processes underlying morphogenesis are crucial to understanding: 1) the source of birth defects, 2) the formation of tumors and progression of cancer, and 3) basic principles of tissue engineering. In this paper, we first review the process of tissue convergent-extension of the vertebrate axis and then review models used to study the self-organizing movements from a <span class="hlt">mechanical</span> perspective. We conclude by presenting a relatively simple "wedge-model" that exhibits key emergent properties of convergent extension such as the coupling between tissue stiffness, cell intercalation forces, and tissue elongation forces. PMID:19815213</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19815213','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19815213"><span id="translatedtitle">Emergent morphogenesis: elastic <span class="hlt">mechanics</span> of a self-<span class="hlt">deforming</span> tissue.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Davidson, Lance A; Joshi, Sagar D; Kim, Hye Young; von Dassow, Michelangelo; Zhang, Lin; Zhou, Jian</p> <p>2010-01-01</p> <p>Multicellular organisms are generated by coordinated cell movements during morphogenesis. Convergent extension is a key tissue movement that organizes mesoderm, ectoderm, and endoderm in vertebrate embryos. The goals of researchers studying convergent extension, and morphogenesis in general, include understanding the molecular pathways that control cell identity, establish fields of cell types, and regulate cell behaviors. Cell identity, the size and boundaries of tissues, and the behaviors exhibited by those cells shape the developing embryo; however, there is a fundamental gap between understanding the molecular pathways that control processes within single cells and understanding how cells work together to assemble multicellular structures. Theoretical and experimental biomechanics of embryonic tissues are increasingly being used to bridge that gap. The efforts to map molecular pathways and the <span class="hlt">mechanical</span> processes underlying morphogenesis are crucial to understanding: (1) the source of birth defects, (2) the formation of tumors and progression of cancer, and (3) basic principles of tissue engineering. In this paper, we first review the process of tissue convergent extension of the vertebrate axis and then review models used to study the self-organizing movements from a <span class="hlt">mechanical</span> perspective. We conclude by presenting a relatively simple "wedge-model" that exhibits key emergent properties of convergent extension such as the coupling between tissue stiffness, cell intercalation forces, and tissue elongation forces. PMID:19815213</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMMR44A..01M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMMR44A..01M&link_type=ABSTRACT"><span id="translatedtitle">Time-dependent <span class="hlt">Deformation</span> in Porous Rocks Driven by Chemo-<span class="hlt">mechanical</span> Coupling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meredith, P. G.; Brantut, N.; Heap, M. J.; Baud, P.</p> <p>2015-12-01</p> <p>We report results from triaxial <span class="hlt">deformation</span> of porous sandstone and limestone conducted to determine the time-dependency of <span class="hlt">deformation</span>. Experiments were run on water-saturated samples under constant differential stress (creep) conditions. In sandstone, the <span class="hlt">deformation</span> is entirely brittle for all levels of stress and for all resulting strain rates. The strain rate during creep is very stress sensitive, with a change of only 20 MPa in differential stress producing three orders of magnitude change in strain rate. Failure occurs by localized shear faulting after an extended period of dilatant microcracking, as evidenced by the output of acoustic emissions. By contrast, the behaviour of limestone is more complex. At low effective pressure, the creep behavior is brittle and characterised by the same features as observed for sandstone; a decelerating phase of creep, followed by an inflection and then an accelerating creep phase leading to macroscopic failure. Similarly, only a small amount of inelastic strain is accommodated before failure, and P wave speeds measured throughout <span class="hlt">deformation</span> decrease continuously, indicating a continuous increase in dilatant crack damage. At higher effective pressure, brittle creep still occurs, but the details of the time-dependent <span class="hlt">deformation</span> behavior are quite different. First, the total amount of accumulated creep strain increases dramatically with decreasing strain rate, and no localized failure occurs even at these higher strains. Second, the rate of decrease in P wave speeds during <span class="hlt">deformation</span> decreases with decreasing strain rate; indicating that less damage is accumulated per unit strain when the strain rate is lower. Third, complementary strain rate stepping experiments indicate that the <span class="hlt">deformation</span> becomes more compactant at lower strain rates. Taken together, these observations suggest that rate-dependent compactive <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> compete with dilatant subcritical crack growth during creep in limestone under low</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030012704','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030012704"><span id="translatedtitle">Projection Moire Interferometry for Rotorcraft Applications: <span class="hlt">Deformation</span> Measurements of <span class="hlt">Active</span> Twist Rotor Blades</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fleming, Gary A.; Soto, Hector L.; South, Bruce W.</p> <p>2002-01-01</p> <p>Projection Moire Interferometry (PMI) has been used during wind tunnel tests to obtain azimuthally dependent blade bending and twist measurements for a 4-bladed <span class="hlt">Active</span> Twist Rotor (ATR) system in simulated forward flight. The ATR concept offers a means to reduce rotor vibratory loads and noise by using piezoelectric <span class="hlt">active</span> fiber composite actuators embedded in the blade structure to twist each blade as they rotate throughout the rotor azimuth. The twist imparted on the blades for blade control causes significant changes in blade loading, resulting in complex blade <span class="hlt">deformation</span> consisting of coupled bending and twist. Measurement of this blade <span class="hlt">deformation</span> is critical in understanding the overall behavior of the ATR system and the physical <span class="hlt">mechanisms</span> causing the reduction in rotor loads and noise. PMI is a non-contacting, video-based optical measurement technique capable of obtaining spatially continuous structural <span class="hlt">deformation</span> measurements over the entire object surface within the PMI system field-of-view. When applied to rotorcraft testing, PMI can be used to measure the azimuth-dependent blade bending and twist along the full span of the rotor blade. This paper presents the PMI technique as applied to rotorcraft testing, and provides results obtained during the ATR tests demonstrating the PMI system performance. PMI measurements acquired at select blade actuation conditions generating minimum and maximum rotor loads are provided to explore the interrelationship between rotor loads, blade bending, and twist.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001JMEP...10..731B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001JMEP...10..731B&link_type=ABSTRACT"><span id="translatedtitle">Hot <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in Ti-5.5Al-1Fe alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Balasubrahmanyam, V. V.; Prasad, Y. V. R. K.</p> <p>2001-12-01</p> <p>The <span class="hlt">mechanisms</span> of hot <span class="hlt">deformation</span> in the alloy Ti-5.5Al-1Fe have been studied in the temperature range 750 to 1150 °C and with the true strain rate varying from 0.001 to 100 s-1 by means of isothermal compression tests. At temperatures below β transus and low strain rates, the alloy exhibited steady-state flow behavior, while, at high strain rates, either continuous flow softening or work hardening followed by flow softening was observed. In the β region, the <span class="hlt">deformation</span> behavior is characterized by steady-state behavior at low strain rates, yield drops at intermediate strain rates, and oscillations at high strain rates. The processing maps revealed two domains. (1) In the temperature range 750 to 1050 °C and at strain rates lower than 0.01 s-1, the material exhibits fine-grained superplasticity. The apparent <span class="hlt">activation</span> energy for superplastic <span class="hlt">deformation</span> is estimated to be about 328 kJ/mole. The optimum conditions for superplasticity are 825 °C and 0.001 s-1. (2) In the β region, a domain occurs at temperatures above 1100 °C and at strain rates from 0.001 to 0.1 s-1 with its peak efficiency of 47% occurring at 1150 °C and 0.01 s1. On the basis of kinetic analysis, tensile ductility, and grain size variation, this domain is interpreted to represent dynamic recrystallization (DRX) of β phase. The apparent <span class="hlt">activation</span> energy for DRX is estimated to be 238 kJ/mole. The grain size ( d) is linearly dependent on the Zener-Hollomon parameter ( Z) per the equation log (d) = 2.86 - 0.023 log (Z) In the regimes in the temperature range 750 to 825 °C and at strain rates from 0.01 to 1.2 s-1 and at temperatures above 1050 °C and strain rates above 10 s-1, the material exhibits flow instabilities manifested in the form of adiabatic shear bands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.T41A4591L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.T41A4591L"><span id="translatedtitle">Brittle, creep and melt damage <span class="hlt">mechanics</span> of the lithosphere: is slow creep <span class="hlt">deformation</span> a key to intraplate volcanic provinces?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, J.; Regenauer-Lieb, K.; Karrech, A.; Rosenbaum, G.; Lyakhovsky, V.</p> <p>2014-12-01</p> <p>We investigate the problem of intraplate melt generation with the aim of understanding spatial and temporal relationships between magmatism and extremely slow intraplate <span class="hlt">deformation</span>. We present numerical models that consider feedback between melt generation and lithospheric <span class="hlt">deformation</span> and incorporate three different damage <span class="hlt">mechanisms</span>: brittle damage, creep damage, and melt damage. Melt conditions are calculated with a Gibbs energy minimization method, and the energy equation solved self-consistently for latent heat and shear heating effects. We use an extremely slowly lithosphere extension model (1-1.5 mm/y) to investigate the <span class="hlt">mechanics</span> leading to intraplate volcanism in a cold lithosphere (~50mW/m2) such as the Harrat Ash-Shaam volcanic field in NW Arabia. We find that the extremely slow extension is a key to a very potent melt transfer <span class="hlt">mechanism</span> through the lithosphere. The <span class="hlt">mechanism</span> relies on multiple feedback <span class="hlt">mechanisms</span> <span class="hlt">active</span> in the accommodation of strain in the presence of fluids. These are capable of generating melts in the lithosphere/asthenosphere even in regions of relatively low heat flux. Once low degrees of partial melts are generated, the triple feedback between brittle-creep and melt damage leads to high porosity lithospheric-scale shear zones capable of transferring melts and fluids to the surface. Efficient localization in the weaker ductile domains implies that the final pattern of strain distribution is controlled by slow creep from below rather than by brittle <span class="hlt">deformation</span> from above. Our model provides an explanation for intraplate volcanic provinces, which appear to rely on slowly <span class="hlt">deforming</span> lithospheres. A significant finding is that slow extension, rather than fast extension, can localize melt damage more effectively in the deeper creeping section of the lithosphere. This finding may have profound implications to the fundamental dynamic control on intraplate volcanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PMag...93.2913W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PMag...93.2913W"><span id="translatedtitle">Accommodation <span class="hlt">mechanisms</span> for grain boundary sliding as inferred from texture evolution during superplastic <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watanabe, Hiroyuki; Kurimoto, Kouhei; Uesugi, Tokuteru; Takigawa, Yorinobu; Higashi, Kenji</p> <p>2013-08-01</p> <p>To gain insight into accommodation <span class="hlt">mechanisms</span> for local stress concentrations produced by grain boundary sliding (GBS), we systematically examined texture evolution within a superplastic magnesium alloy undergoing <span class="hlt">deformation</span> at a relatively low <span class="hlt">deformation</span> temperature (at which basal slip is known to be the preferred slip system in magnesium). Although we did observe an overall weakening of the initial basal texture during superplastic <span class="hlt">deformation</span>, we also observed within the interior of the specimen a convergent evolution that depends on loading direction. We attribute this texture evolution within the bulk to the competing effects of (a) orientation divergence due to grain rotation accompanied by GBS and (b) convergent evolution due to slip, which acts primarily as an accommodation <span class="hlt">mechanism</span> for GBS. In contrast, at the near-surface, we found the initial orientation to be preserved, indicating that slip accommodation is less important near the surface than within the bulk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JPhCS.395a2146N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JPhCS.395a2146N"><span id="translatedtitle">Modelling heat and mass transfer in bread baking with <span class="hlt">mechanical</span> <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nicolas, V.; Salagnac, P.; Glouannec, P.; Ploteau, J.-P.; Jury, V.; Boillereaux, L.</p> <p>2012-11-01</p> <p>In this paper, the thermo-hydric behaviour of bread during baking is studied. A numerical model has been developed with Comsol Multiphysics© software. The model takes into account the heat and mass transfers in the bread and the phenomenon of swelling. This model predicts the evolution of temperature, moisture, gas pressure and <span class="hlt">deformation</span> in French "baguette" during baking. Local <span class="hlt">deformation</span> is included in equations using solid phase conservation and, global <span class="hlt">deformation</span> is calculated using a viscous <span class="hlt">mechanic</span> model. Boundary conditions are specified with the sole temperature model and vapour pressure estimation of the oven during baking. The model results are compared with experimental data for a classic baking. Then, the model is analysed according to physical properties of bread and solicitations for a better understanding of the interactions between different <span class="hlt">mechanisms</span> within the porous matrix.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MS%26E...91a2025L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MS%26E...91a2025L"><span id="translatedtitle">Preferred Orientation Evolution of Olivine Grains as an Indicator of Change in the <span class="hlt">Deformation</span> <span class="hlt">Mechanism</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lychagin, D. V.; Tishin, P. A.; Kulkov, A. S.; Chernyshov, A. I.; Alfyorova, E. A.</p> <p>2015-09-01</p> <p>The paper presents the results of investigations of <span class="hlt">deformed</span> natural polycrystalline olivine. The relationship of the structure of polycrystalline olivine grains to three modal size distributions has been revealed. Grains of different size were observed to be strained at threshold temperatures of 950, 775, and 650°C. It has been demonstrated that the microstructure develops as the dislocation <span class="hlt">mechanism</span> changes from diffusion creep to grain boundary sliding. The changes in <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> promote the change in the preferred crystallographic orientations of olivine from type A to type D and then to type B. The relation of the transitions between different types of orientations to the conditions of <span class="hlt">deformation</span> in the lower layers of the lithosphere at the plate boundaries is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5260832','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5260832"><span id="translatedtitle">Fuel rod <span class="hlt">mechanical</span> <span class="hlt">deformation</span> during the PBF/LOFT lead rod loss-of-coolant experiments</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Varacalle, Jr., D. J.; MacDonald, P. E.; Shiozawa, S.; Driskell, W. E.</p> <p>1980-01-01</p> <p>Results of four PBF/LOFT Lead Rod (LLR) sequential blowdown tests conducted in the Power Burst Facility (PBF) are presented. Each test employed four separately shrouded fuel rods. The primary objective of the test series was to evaluate the extent of <span class="hlt">mechanical</span> <span class="hlt">deformation</span> that would be expected to occur to low pressure (0.1 MPa), light water reactor design fuel rods when subjected to a series of double ended cold leg break loss-of-coolant accident (LOCA) tests, and to determine whether subjecting these <span class="hlt">deformed</span> fuel rods to subsequent testing would result in rod failure. The extent of <span class="hlt">mechanical</span> <span class="hlt">deformation</span> (buckling, collapse, or waisting of the cladding) was evaluated by comparison of cladding temperature and system pressure measurements with out-of-pile experimental data, and by posttest visual examinations and cladding diametral measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/571899','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/571899"><span id="translatedtitle">The <span class="hlt">mechanical</span> behavior and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of Nb-Al-V alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Tappin, D.K.; Horspool, D.N.; Smith, L.S.; Aindow, M.</p> <p>1997-12-31</p> <p>A series of Nb-Al-V alloys containing 20--40 at.% V and 10--25 at.% Al have been investigated. The phase distributions in the alloys indicate that Al promotes the formation of the A15 phase whilst V stabilizes a B2 phase. Room temperature compression testing revealed that the B2 is inherently ductile such that for the alloys with less than 40% by volume of the A15 phase, strains of over 50% were obtained easily. The 2% offset yield stresses of these alloys did not vary significantly with composition, being 1.2 {+-} 0.1 GPa in each case. TEM studies were used to show that the <span class="hlt">deformation</span> in the B2 phase occurs predominantly by the glide of screw-type super-partial dislocations with b = 1/2<111> on {l_brace}110{r_brace} and {l_brace}112{r_brace}. In some alloys this dislocation <span class="hlt">activity</span> was preceded by the formation of pseudo-twins, via a martensitic shear transformation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006SPIE.6143..712N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006SPIE.6143..712N"><span id="translatedtitle">Real-time <span class="hlt">deformations</span> of organ based on structural <span class="hlt">mechanics</span> for surgical simulators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakaguchi, Toshiya; Tagaya, Masashi; Tamura, Nobuhiko; Tsumura, Norimichi; Miyake, Yoichi</p> <p>2006-03-01</p> <p>This research proposes the <span class="hlt">deformation</span> model of organs for the development of the medical training system using Virtual Reality (VR) technology. First, the proposed model calculates the strains of coordinate axis. Secondly, the <span class="hlt">deformation</span> is obtained by mapping the coordinate of the object to the strained coordinate. We assume the beams in the coordinate space to calculate the strain of the coordinate axis. The forces acting on the object are converted to the forces applied to the beams. The bend and the twist of the beams are calculated based on the theory of structural <span class="hlt">mechanics</span>. The bend is derived by the finite element method. We propose two <span class="hlt">deformation</span> methods which differ in the position of the beams in the coordinate space. One method locates the beams along the three orthogonal axes (x, y, z). Another method locates the beam in the area where the <span class="hlt">deformation</span> is large. In addition, the strain of the coordinate axis is attenuated in proportion to the distance from the point of action to consider the attenuation of the stress which is a viscoelastic feature of the organs. The proposed model needs less computational cost compared to the conventional <span class="hlt">deformation</span> method since our model does not need to divide the object into the elasticity element. The proposed model was implemented in the laparoscopic surgery training system, and a real-time <span class="hlt">deformation</span> can be realized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JEMat..44.3486C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JEMat..44.3486C"><span id="translatedtitle">Recrystallization as a Growth <span class="hlt">Mechanism</span> for Whiskers on Plastically <span class="hlt">Deformed</span> Sn Films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chang, Jaewon; Kang, Sung K.; Lee, Jae-Ho; Kim, Keun-Soo; Lee, Hyuck Mo</p> <p>2015-10-01</p> <p>Sn whiskers are becoming a serious reliability issue in Pb-free electronic packaging applications. Sn whiskers are also observed in connector parts of electronics as well as on electroplated surface finishes. Sn whiskers found in connector parts are known to behave differently from the typical Sn whiskers reported on electroplated Sn surfaces. In this study, Sn whiskers on plastically <span class="hlt">deformed</span> Sn-rich films were investigated to understand their growth behavior to establish mitigation strategies for Sn-rich films used in connectors. Therefore, a microhardness indentation technique was applied to plastically <span class="hlt">deform</span> electroplated matte Sn samples, followed by temperature/humidity (T/H) testing (30°C, dry air). Each sample was examined by scanning electron microscopy at regular time intervals up to 4000 h. Various morphologies of Sn whiskers on plastically <span class="hlt">deformed</span> matte Sn films were observed, and their growth statistics and kinetics are analyzed in terms of the plating conditions and plastic <span class="hlt">deformation</span> by using transmission electron microscopy, x-ray diffraction, and the focused ion-beam technique. Sn whiskers were observed on plastically <span class="hlt">deformed</span> regions of thin (2- μm) and thick (10- μm) matte Sn films, regardless of the current density applied. Plastic <span class="hlt">deformation</span> was found to promote whisker formation on matte Sn films. A high density of dislocations and newly formed fine Sn subgrains were observed in <span class="hlt">deformed</span> grains. In addition, the recrystallized grains and Cu6Sn5 intermetallic compound grew further with increasing time. Finally, a growth <span class="hlt">mechanism</span> for <span class="hlt">deformation</span>-induced Sn whiskers is proposed based on a recrystallization model combined with the formation of Cu6Sn5.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014GGG....15.5001G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014GGG....15.5001G"><span id="translatedtitle"><span class="hlt">Mechanical</span> properties and processes of <span class="hlt">deformation</span> in shallow sedimentary rocks from subduction zones: An experimental study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gadenne, Leslie; Raimbourg, Hugues; Champallier, Rémi; Yamamoto, Yuzuru</p> <p>2014-12-01</p> <p>better constrain the <span class="hlt">mechanical</span> behavior of sediments accreted to accretionary prism, we conducted triaxial <span class="hlt">mechanical</span> tests on natural samples from the Miura-Boso paleo-accretionary prism (Japan) in drained conditions with confining pressures up to 200 MPa as well as postexperiments P-wave velocity (Vp) measurements. During experiments, <span class="hlt">deformation</span> is principally noncoaxial and accommodated by two successive modes of <span class="hlt">deformation</span>, both associated with strain-hardening and velocity-strengthening behavior: (1) compaction-assisted shearing, distributed in a several mm-wide shear zone and (2) faulting, localized within a few tens of μm-wide, dilatant fault zone. <span class="hlt">Deformation</span> is also associated with (1) a decrease in Young's modulus all over the tests, (2) anomalously low Vp in the <span class="hlt">deformed</span> samples compared to their porosity and (3) an increase in sensitivity of Vp to effective pressure. We interpret this evolution of the poroelastic properties of the material as reflecting the progressive breakage of intergrain cement and the formation of microcracks along with macroscopic <span class="hlt">deformation</span>. When applied to natural conditions, these results suggest that the <span class="hlt">deformation</span> style (localized versus distributed) of shallow (z < a few km) sediments is mainly controlled by the variations in stress/strain rate during the seismic cycle and is therefore independent of the porosity of sediments. Finally, we show that the effect of strain, through cement breakage and microcracks formation, may lower Vp for effective pressure up to 40 MPa. As a consequence, the low Vp anomalies observed in Nankai accretionary prisms by seismic imaging between 2 and 4 km depth could reflect sediment <span class="hlt">deformation</span> rather than porosity anomalies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4915725','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4915725"><span id="translatedtitle">Large <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span>, Plasticity, and Failure of an Individual Collagen Fibril With Different Mineral Content</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J</p> <p>2016-01-01</p> <p>ABSTRACT Mineralized collagen fibrils are composed of tropocollagen molecules and mineral crystals derived from hydroxyapatite to form a composite material that combines optimal properties of both constituents and exhibits incredible strength and toughness. Their complex hierarchical structure allows collagen fibrils to sustain large <span class="hlt">deformation</span> without breaking. In this study, we report a mesoscale model of a single mineralized collagen fibril using a bottom‐up approach. By conserving the three‐dimensional structure and the entanglement of the molecules, we were able to construct finite‐size fibril models that allowed us to explore the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> which govern their <span class="hlt">mechanical</span> behavior under large <span class="hlt">deformation</span>. We investigated the tensile behavior of a single collagen fibril with various intrafibrillar mineral content and found that a mineralized collagen fibril can present up to five different <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> to dissipate energy. These <span class="hlt">mechanisms</span> include molecular uncoiling, molecular stretching, mineral/collagen sliding, molecular slippage, and crystal dissociation. By multiplying its sources of energy dissipation and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, a collagen fibril can reach impressive strength and toughness. Adding mineral into the collagen fibril can increase its strength up to 10 times and its toughness up to 35 times. Combining crosslinks with mineral makes the fibril stiffer but more brittle. We also found that a mineralized fibril reaches its maximum toughness to density and strength to density ratios for a mineral density of around 30%. This result, in good agreement with experimental observations, attests that bone tissue is optimized <span class="hlt">mechanically</span> to remain lightweight but maintain strength and toughness. © 2015 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals, Inc. on behalf of American Society for Bone and Mineral Research (ASBMR). PMID:26866939</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1511290E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1511290E"><span id="translatedtitle">Influence of rheological and frictional slip properties on fault <span class="hlt">mechanics</span>, <span class="hlt">deformation</span> rates and localization phenomena: The Corinth Rift case</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>El Arem, Saber; Lyon-Caen, Helene; Bernard, Pascal; Garaud, Jean-Didier; Rolandone, Frederique; Briole, Pierre</p> <p>2013-04-01</p> <p>The Gulf of Corinth in Greece is one of the most <span class="hlt">active</span> extensional regions in the Mediterranean area. However, there are still open questions concerning the role and the geometry of the numerous <span class="hlt">active</span> faults bordering the basin, as well as the <span class="hlt">mechanisms</span> governing the seismicity. In geodynamics, advances in understanding complex physical processes such as lithospheric <span class="hlt">deformation</span> or faulting <span class="hlt">mechanics</span> rely increasingly on the development of sophisticated numerical modeling able to quantify the influence of the unknown rheological parameters and involved complex phenomena. In the framework of the Corinth Rift Laboratory (CRL http://crlab.eu) project, this work is devoted to the exploration of some aspects of fault <span class="hlt">mechanics</span>. We start by considering a two-dimensional numerical model of one single normal fault slipping continuously embeded in an elastic-viscoplastic media. In this case, the effects of rheological and geometrical parameters on the <span class="hlt">deformation</span> localization, on the horizontal and vertical surface <span class="hlt">deformation</span> velocities are examined. The openning and uplift rates at different extension periods are compared to the GPS velocities measured in the CRL region. This comparaison allows to constrain the upper crust rheological parameters as well as their variation with depth . We then introduce a second fault, antithetic to the first one, for a more realistic representation of the CRL region where faults dipping north and south bordering the gulf of Corinth are clearly identified. The effect of the antithetic fault in accommodating the lithospheric extension is discussed. Also, changes in the distribution of the frictional-plastic <span class="hlt">deformation</span> as well as in the onshore and offshore topography are highlighted. The last part of this work is dedicated to the study of a fault zone over multiple seismic cycles. Long term <span class="hlt">deformation</span> obtained from a continuously sliping fault model is compared to that obtained from the superposition of seismic cycles and the fine</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27547684','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27547684"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in a coal mine roadway in extremely swelling soft rock.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Li, Qinghai; Shi, Weiping; Yang, Renshu</p> <p>2016-01-01</p> <p>The problem of roadway support in swelling soft rock was one of the challenging problems during mining. For most geological conditions, combinations of two or more supporting approaches could meet the requirements of most roadways; however, in extremely swelling soft rock, combined approaches even could not control large <span class="hlt">deformations</span>. The purpose of this work was to probe the roadway <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in extremely swelling soft rock. Based on the main return air-way in a coal mine, <span class="hlt">deformation</span> monitoring and geomechanical analysis were conducted, as well as plastic zone <span class="hlt">mechanical</span> model was analysed. Results indicated that this soft rock was potentially very swelling. When the ground stress acted alone, the support strength needed in situ was not too large and combined supporting approaches could meet this requirement; however, when this potential released, the roadway would undergo permanent <span class="hlt">deformation</span>. When the loose zone reached 3 m within surrounding rock, remote stress p ∞ and supporting stress P presented a linear relationship. Namely, the greater the swelling stress, the more difficult it would be in roadway supporting. So in this extremely swelling soft rock, a better way to control roadway <span class="hlt">deformation</span> was to control the releasing of surrounding rock's swelling potential. PMID:27547684</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21470233','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21470233"><span id="translatedtitle">Electron-<span class="hlt">deformation</span> <span class="hlt">mechanism</span> of photoexcitation of hypersound in semiconductors in a dc electric field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chigarev, N V</p> <p>2002-09-30</p> <p>The effect of a dc electric field on photoexcitation of a hypersonic pulse in a semiconductor via an electron-<span class="hlt">deformation</span> <span class="hlt">mechanism</span> is studied. The profiles of acoustic pulses are simulated for different directions of the electric field. (laser applications and other topics in quantum electronics)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/936311','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/936311"><span id="translatedtitle"><span class="hlt">Deformation</span> Microstructures and Creep <span class="hlt">Mechanisms</span> in Advanced ZR-Based Cladding Under Biazal Loading</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>K. Linga Murty</p> <p>2008-08-11</p> <p>Investigate creep behavior of Zr-based cladding tubes with attention to basic creep <span class="hlt">mechanisms</span> and transitions in them at low stresses and/or temperatures and study the dislocation microstructures of <span class="hlt">deformed</span> samples for correlation with the underlying micromechanism of creep</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..SHK.M1095R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..SHK.M1095R"><span id="translatedtitle">Atomistic <span class="hlt">Mechanism</span> of Plastic <span class="hlt">Deformation</span> During Nano-indentation of Titanium Aluminide</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rino, Jose; Dasilva, Claudio</p> <p>2013-06-01</p> <p>The <span class="hlt">mechanisms</span> governing defect nucleation in solids are of great interest in all material science branches. Atomistic computer simulations such as Molecular Dynamics (MD), has been providing more understanding of subsurface <span class="hlt">deformations</span>, bringing out details of atomic structures and dynamics of defects within the material. In the present work we show the first simulation measurements within an atomistic resolution of the <span class="hlt">mechanical</span> properties of titanium aluminide intermetallic compound (TiAl), which is a promising candidate for high temperature applications with remarkable properties, such as: attractive combination of low density, high melting temperature, high elastic modulus, and strength retention at elevated temperatures, besides its good creep properties. Through calculations of local pressure, local shear stress and spatial rearrangements of atoms beneath the indenter, it was possible to quantify the indentation damage on the structure. We have founded that prismatic dislocations mediate the emission and interaction of dislocations and the <span class="hlt">activated</span> slip planes are associated with the Thompson tetrahedron. Furthermore, using the load-penetration depth response, we were able to estimate the elastic modulus and the hardness of the TiAl alloy. All our findings are in well agreement with experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V51D2695O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V51D2695O"><span id="translatedtitle"><span class="hlt">Mechanics</span> of brittle <span class="hlt">deformation</span> and slope failure at the North Menan Butte tuff cone, Eastern Snake River Plain, Idaho</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Okubo, C. H.</p> <p>2013-12-01</p> <p>The Menan Volcanic Complex consists of phreatomagmatic tuff cones that were emplaced as part of the regional volcanic <span class="hlt">activity</span> in the Snake River Plain during the late Pleistocene. These tuff cones, the ';Menan Buttes', resulted from the eruption of basaltic magma through water-saturated alluvium and older basalts along the Snake River. The tuffs are composed primarily of basaltic glass with occasional plagioclase and olivine phenocrysts. The tuff is hydrothermally altered to a massive palagonitic tuff at depth but is otherwise poorly welded. Mass movements along the flanks of the cones were contemporaneous with tuff deposition. These slope failures are manifest as cm- to meter-scale pure folds, faults and fault-related folds, as well as larger slumps that are tens to a few hundred meters wide. Previous investigations classified the structural discontinuities at North Menan Butte based on orientation and sense of displacement, and all were recognized as opening-mode or shear fractures (Russell and Brisbin, 1990). This earlier work also used a generalized model of static (i.e., aseismic) gravity-driven shear failure within cohesionless soils to infer a possible origin for these fractures through slope failure. Recent work at North Menan Butte has provided novel insight into the styles of brittle <span class="hlt">deformation</span> present, the effect of this <span class="hlt">deformation</span> on the circulation of subsurface fluids within the tuff cone, as well as the <span class="hlt">mechanisms</span> of the observed slope failures. Field observations reveal that the brittle <span class="hlt">deformation</span>, previously classified as fractures, is manifest as <span class="hlt">deformation</span> bands within the non-altered, poorly welded portions of the tuff. Both dilational and compactional bands, with shear, are observed. Slumps are bounded by normal faults, which are found to have developed within clusters of <span class="hlt">deformation</span> bands. <span class="hlt">Deformation</span> bands along the down-slope ends of these failure surfaces are predominantly compactional in nature. These bands have a ~3800 millidarcy</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013Tectp.593...95S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013Tectp.593...95S"><span id="translatedtitle">FEM analysis of <span class="hlt">deformation</span> localization <span class="hlt">mechanisms</span> in a 3-D fractured medium under rotating compressive stress orientations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strijker, Geertje; Beekman, Fred; Bertotti, Giovanni; Luthi, Stefan M.</p> <p>2013-05-01</p> <p>Stress distributions and <span class="hlt">deformation</span> patterns in a medium with a pre-existing fracture set are analyzed as a function of the remote compressive stress orientation (σH) using finite element models with increasingly complex fracture configurations. Slip along the fractures causes <span class="hlt">deformation</span> localization at the tips as wing cracks or shear zones. The <span class="hlt">deformation</span> intensity is proportional to the amount of slip, attaining a peak value for α = 45° (α: angle between the fracture strike and σH) and slip is linearly proportional with fracture length. Wing cracks develop for high <span class="hlt">deformation</span> intensities for 30° < α < 60°, whereas primary plastic shear zones develop for low <span class="hlt">deformation</span> intensities. Additionally, two types of secondary shear zones develop for α < 30° and α > 60°, with constant angles of 135° and - 60° with σH, respectively. <span class="hlt">Mechanical</span> interaction between fractures in a fracture zone, quantified as change in slip compared to an isolated fracture, decreases with increasing fracture separation. Fracture underlap elongates the fracture length and therefore increases the amount of slip, while fracture overlap exhibits the opposite effect. Fracture slip decreases with an increasing amount of directly adjacent fractures. <span class="hlt">Mechanical</span> interaction becomes negligible for fracture configurations with spacing-to-length and spacing-to-overlap ratios exceeding 0.5 and that in this case fractures are decoupled. Independent of the pre-existing fracture configuration, the development of a secondary systematic fracture set driven by a remote stress rotation is dominated by σH; development of wing cracks or shear zones is restricted to the fracture tips. Blocks with tapered geometries are present in models with a variable fracture strike, where the maximum principal stress (σ1, applying the geological convention that compressive stresses are positive) trajectories consistently deviate from σH; the presence of two systematic σ1 trajectory orientations suggests</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.7706B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.7706B"><span id="translatedtitle"><span class="hlt">Mechanical</span> and microstructural development of Carrara marble with pre-existing <span class="hlt">deformation</span> history in torsion experiments</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bruijn, R. H. C.; Burlini, L.; Kunze, K.</p> <p>2009-04-01</p> <p>The <span class="hlt">deformation</span> behaviour of Carrara marble has been studied mostly by performing <span class="hlt">deformation</span> experiments on initially undeformed samples. In this study, torsion experiments on Carrara marble with a pre-existing <span class="hlt">deformation</span> history have been conducted and analysed in terms of both <span class="hlt">mechanical</span> and microstructural development. Torsion experiments have been conducted to <span class="hlt">deform</span> initially <span class="hlt">deformed</span> Carrara marble samples until a bulk shear strain of gamma 1 or 2.6 was reached. For Carrara marble experiments typically yielding is followed by strain hardening until a peak stress is reached around a shear strain gamma = 1 , after which a weakening phase occurs. Weakening gradually develops into a steady-state creep. During hardening, a shear microstructure and CPO develops; afterwards dynamic recrystallization becomes increasingly effective resulting in pervasively recrystallized microstructure and recrystallization CPO at gamma 5 and higher. Starting material of the new experiments are sandwich samples consisting of three equally sized segments: a top segment previously <span class="hlt">deformed</span> counter clockwise, an undeformed centre segment and a previously clockwise <span class="hlt">deformed</span> segment in the bottom. Shear strain of the <span class="hlt">deformed</span> bottom and top segments are equal in magnitude but opposite in sense and correspond with the shear strain of the actual experiments (e.g. sample of the gamma 1 experiment, consists of initially gamma 1 <span class="hlt">deformed</span> top and bottom segments). All torsion experiments were conducted using a Paterson type internally heated gas-medium <span class="hlt">deformation</span> apparatus equipped with a torsion actuator, under temperature and pressure conditions of 1000K and 300 MPa, respectively. Angular displacement rates during the experiments correspond to a strain rate of 3.0x10-4 s-1 at the outer cylinder periphery. The second <span class="hlt">deformation</span> event imposed on the sandwich sample is always counter clockwise (or dextral). The sandwich experiment to gamma 1 shows a weakly developed strain partitioning</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMMR41D2694O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMMR41D2694O"><span id="translatedtitle">Microstructural Analysis of Coupled <span class="hlt">Mechanical</span> and Chemical Diagenetic Processes in <span class="hlt">Deformation</span> Bands in Sandstone</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>O'Brien, C. M.; Eichhubl, P.; Elliott, S. J.</p> <p>2015-12-01</p> <p><span class="hlt">Deformation</span> bands in sandstone and other porous rock have been shown to act as barriers or baffles to fluid flow. Changes in flow properties are related to microscale textural changes that occur within the <span class="hlt">deformation</span> bands through coupled <span class="hlt">mechanical</span> and chemical diagenetic processes. Microscale textures relating to flow properties, such as brittle grain <span class="hlt">deformation</span>, preferred cementation, and the entrainment of fines within bands can be studied using scanning electron microscopy (SEM) imaging techniques. Conventional techniques for imaging <span class="hlt">deformation</span> bands by SEM involve using <span class="hlt">mechanically</span> polished thin sections. However, <span class="hlt">mechanical</span> polishing can cause induced sample damage that limits microstructural observations. To mitigate sample damage, we use large-area and cross-sectional Ar ion beam milling to prepare <span class="hlt">deformation</span> band samples for SEM imaging. These techniques preserve sample integrity allowing the imaging of cement and pore textures at submicron resolution. In an ion milled <span class="hlt">deformation</span> band from the Entrada sandstone, we observe delicate euhedral quartz crystals that precipitated after band formation. In the same band, broken grain fragments that occupy space between larger framework grains are angular in shape, suggesting that they still bear freshly broken surfaces, not dulled and rounded by grain dissolution and cement overgrowth. The lack of widespread isopachous cement on grain fragments, and the observation, instead, of isolated slender quartz cement prisms indicates that cementation in these bands is highly localized. These localized cement growths increase roughness in the pore walls, increasing surface area and tortuosity in the flow pathway through the band. This may reduce permeability in the band without completely occluding flow pathways and pore connections within the bands.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPRS..102..140L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPRS..102..140L"><span id="translatedtitle">Water flow based geometric <span class="hlt">active</span> <span class="hlt">deformable</span> model for road network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leninisha, Shanmugam; Vani, Kaliaperumal</p> <p>2015-04-01</p> <p>A width and color based geometric <span class="hlt">active</span> <span class="hlt">deformable</span> model is proposed for road network extraction from remote sensing images with minimal human interception. Orientation and width of road are computed from a single manual seed point, from which the propagation starts both right and left hand directions of the starting point, which extracts the interconnected road network from the aerial or high spatial resolution satellite image automatically. Here the propagation (like water flow in canal with defined boundary) is restricted with color and width of the road. Road extraction is done for linear, curvilinear (U shape and S shape) roads first, irrespective of width and color. Then, this algorithm is improved to extract road with junctions in a shape of L, T and X along with center line. Roads with small break or disconnected roads are also extracts by a modified version of this same algorithm. This methodology is tested and evaluated with various remote sensing images. The experimental results show that the proposed method is efficient and extracting roads accurately with less computation time. However, in complex urban areas, the identification accuracy declines due to the various sizes of obstacles, over bridges, multilane etc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3244784','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3244784"><span id="translatedtitle">Molecular Dynamics Simulation of Nanoindentation-induced <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> and Phase Transformation in Monocrystalline Silicon</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2008-01-01</p> <p>This work presents the molecular dynamics approach toward <span class="hlt">mechanical</span> <span class="hlt">deformation</span> and phase transformation <span class="hlt">mechanisms</span> of monocrystalline Si(100) subjected to nanoindentation. We demonstrate phase distributions during loading and unloading stages of both spherical and Berkovich nanoindentations. By searching the presence of the fifth neighboring atom within a non-bonding length, Si-III and Si-XII have been successfully distinguished from Si-I. Crystallinity of this mixed-phase was further identified by radial distribution functions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007Tectp.432...63G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007Tectp.432...63G"><span id="translatedtitle">Analysis of crustal <span class="hlt">deformation</span> in Luzon, Philippines using geodetic observations and earthquake focal <span class="hlt">mechanisms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Galgana, Gerald; Hamburger, Michael; McCaffrey, Robert; Corpuz, Ernesto; Chen, Qizhi</p> <p>2007-03-01</p> <p>We utilize regional GPS velocities from Luzon, Philippines, with focal <span class="hlt">mechanism</span> data from the Harvard Centroid Moment Tensor (CMT) Catalog, to constrain tectonic <span class="hlt">deformation</span> in the complex plate boundary zone between the Philippine Sea Plate and Eurasia (the Sundaland block). Processed satellite imagery and digital elevation models are used with existing gravity anomaly, seismicity, and geologic maps to define a suite of six elastic blocks. Geodetic and focal <span class="hlt">mechanism</span> data are inverted simultaneously to estimate plate rotations and fault-locking parameters for each of the tectonic blocks and faults comprising Luzon. Major tectonic structures that were found to absorb the plate convergence include the Manila Trench (20-100 mm yr - 1 ) and East Luzon Trough (˜ 9-15 mm yr - 1 )/Philippine Trench (˜ 29-34 mm yr - 1 ), which accommodate eastward and westward subduction beneath Luzon, respectively; the left-lateral strike-slip Philippine Fault (˜ 20-40 mm yr - 1 ), and its northward extensions, the Northern Cordillera Fault (˜ 17-37 mm yr - 1 transtension), and the Digdig Fault (˜ 17-27 mm yr - 1 transpression). The Macolod Corridor, a zone of <span class="hlt">active</span> volcanism, crustal thinning, extension, and extensive normal and strike-slip faulting in southwestern Luzon, is associated with left-lateral, transtensional slip of ˜ 5-10 mm yr - 1 . The Marikina Fault, which separates the Central Luzon block from the Southwestern Luzon block, reveals ˜ 10-12 mm yr - 1 of left-lateral transpression. Our analysis suggests that much of the Philippine Fault and associated splays are locked to partly coupled, while the Manila and Philippine trenches appear to be poorly coupled. Luzon is best characterized as a tectonically <span class="hlt">active</span> plate boundary zone, comprising six mobile elastic tectonic blocks between two <span class="hlt">active</span> subduction zones. The Philippine Fault and associated intra-arc faults accommodate much of the trench-parallel component of relative plate motion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARB44004V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARB44004V"><span id="translatedtitle">Topological <span class="hlt">mechanics</span>: from metamaterials to <span class="hlt">active</span> matter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vitelli, Vincenzo</p> <p>2015-03-01</p> <p><span class="hlt">Mechanical</span> metamaterials are artificial structures with unusual properties, such as negative Poisson ratio, bistability or tunable acoustic response, which originate in the geometry of their unit cell. At the heart of such unusual behavior is often a <span class="hlt">mechanism</span>: a motion that does not significantly stretch or compress the links between constituent elements. When <span class="hlt">activated</span> by motors or external fields, these soft motions become the building blocks of robots and smart materials. In this talk, we discuss topological <span class="hlt">mechanisms</span> that possess two key properties: (i) their existence cannot be traced to a local imbalance between degrees of freedom and constraints (ii) they are robust against a wide range of structural <span class="hlt">deformations</span> or changes in material parameters. The continuum elasticity of these <span class="hlt">mechanical</span> structures is captured by non-linear field theories with a topological boundary term similar to topological insulators and quantum Hall systems. We present several applications of these concepts to the design and experimental realization of 2D and 3D topological structures based on linkages, origami, buckling meta-materials and lastly <span class="hlt">active</span> media that break time-reversal symmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920042208&hterms=Hardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHardening','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920042208&hterms=Hardening&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHardening"><span id="translatedtitle">Hardening <span class="hlt">mechanisms</span> in a dynamic strain aging alloy, Hastelloy X, during isothermal and thermomechanical cyclic <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Miner, R. V.; Castelli, M. G.</p> <p>1992-01-01</p> <p>The relative contributions of the hardening <span class="hlt">mechanisms</span> in Hastelloy X during cyclic <span class="hlt">deformation</span> were investigated by conducting isothermal cyclic <span class="hlt">deformation</span> tests within a total strain range of +/-0.3 pct and at several temperatures and strain rates, and thermomechanical tests within several different temperature limits. The results of the TEM examinations and special constant structure tests showed that the precipitation on dislocations of Cr23C6 contributed to hardening, but only after sufficient time above 500 C. Solute drag alone produced very considerable cyclic hardening. Heat dislocation densities, peaking around 10 exp 11 per sq cm, were found to develop at temperatures producing the greatest cyclic hardening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/962323','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/962323"><span id="translatedtitle"><span class="hlt">Mechanism</span> of grain growth during severe plastic <span class="hlt">deformation</span> of a nanocrystalline Ni-Fe alloy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, Hongqi; Wang, Y B; Ho, J C; Liao, X Z; Zhu, Y T; Ringer, S P</p> <p>2009-01-01</p> <p><span class="hlt">Deformation</span> induced grain growth has been widely reported in nanocrystalline materials. However, the grain growth <span class="hlt">mechanism</span> remains an open question. This study applies high-pressure torsion to severely <span class="hlt">deform</span> bulk nanocrystalline Ni-20 wt % Fe disks and uses transmission electron microscopy to characterize the grain growth process. Our results provide solid evidence suggesting that high pressure torsion induced grain growth is achieved primarily via grain rotation for grains much smaller than 100 nm. Dislocations are mainly seen at small-angle subgrain boundaries during the grain growth process but are seen everywhere in grains after the grains have grown large.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JAP...101h3106H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JAP...101h3106H"><span id="translatedtitle"><span class="hlt">Mechanism</span> of mark <span class="hlt">deformation</span> in phase-change media tested in an accelerated environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hirotsune, Akemi; Terao, Motoyasu; Miyauchi, Yasushi; Tokushuku, Nobuhiro; Tamura, Reiji</p> <p>2007-04-01</p> <p>Increased jitter caused by recording marks becoming <span class="hlt">deformed</span> in an accelerated environmental test was investigated and a model where the change in the speed of crystallization is affected by passive oxidation on the amorphous surface of the recording layer was devised. The model clarified the <span class="hlt">mechanism</span> by which <span class="hlt">deformation</span> in the marks caused increased jitter in the accelerated environmental test. Adding nitrogen into the gas when sputtering the protective layer adjacent to the recording film was investigated. It was confirmed that a prototype disk with this protective layer has decreased jitter after a 500 h accelerated test and superior power margins.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27610921','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27610921"><span id="translatedtitle"><span class="hlt">Mechanically</span> <span class="hlt">activated</span> artificial cell by using microfluidics.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ho, Kenneth K Y; Lee, Lap Man; Liu, Allen P</p> <p>2016-01-01</p> <p>All living organisms sense <span class="hlt">mechanical</span> forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a <span class="hlt">deformable</span> flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our <span class="hlt">mechanically</span> <span class="hlt">activated</span> artificial cell through thinning of oil. The development of a microfluidic device to <span class="hlt">mechanically</span> <span class="hlt">activate</span> artificial cells creates new opportunities in force-<span class="hlt">activated</span> synthetic biology. PMID:27610921</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5017192','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5017192"><span id="translatedtitle"><span class="hlt">Mechanically</span> <span class="hlt">activated</span> artificial cell by using microfluidics</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.</p> <p>2016-01-01</p> <p>All living organisms sense <span class="hlt">mechanical</span> forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a <span class="hlt">deformable</span> flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our <span class="hlt">mechanically</span> <span class="hlt">activated</span> artificial cell through thinning of oil. The development of a microfluidic device to <span class="hlt">mechanically</span> <span class="hlt">activate</span> artificial cells creates new opportunities in force-<span class="hlt">activated</span> synthetic biology. PMID:27610921</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010sf2a.conf...77L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010sf2a.conf...77L"><span id="translatedtitle">Space <span class="hlt">active</span> optics: in situ compensation of lightweight primary mirrors' <span class="hlt">deformations</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laslandes, M.; Ferrari, M.; Hugot, E.; Lemaitre, G.</p> <p>2010-12-01</p> <p>The need for both high quality images and light structures is a constant concern in the conception of space telescopes. The goal here is to determine how an <span class="hlt">active</span> optics system could be embarked on a satellite in order to correct the wave front <span class="hlt">deformations</span> of the optical train. The optical aberrations appearing in a space environment are due to mirrors' <span class="hlt">deformations</span>, with three main origins: the thermal variations, the weightlessness conditions and the use of large weightlighted primary mirrors. We are developing a model of <span class="hlt">deformable</span> mirror as minimalist as possible, especially in term of number of actuators, which is able to correct the first Zernike polynomials in a specified range of amplitude and precision. Flight constraints as weight, volume and power consumption are considered. Firstly, such a system is designed according to the equations from the elasticity theory: we determine the geometrical and <span class="hlt">mechanical</span> characteristics of the mirror, the location of the forces to be applied and the way to apply them. Then the concept is validated with a Finite Element Analysis, allowing to optimize the system by taking into account parameters absent from the theory. At the end, the mirror will be realized and characterized in a representative optical configuration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4031491','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4031491"><span id="translatedtitle">A <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of hard metal surrounded by soft metal during roll forming</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>YU, Hailiang; TIEU, A. Kiet; LU, Cheng; LIU, Xiong; GODBOLE, Ajit; LI, Huijun; KONG, Charlie; QIN, Qinghua</p> <p>2014-01-01</p> <p>It is interesting to imagine what would happen when a mixture of soft-boiled eggs and stones is <span class="hlt">deformed</span> together. A foil made of pure Ti is stronger than that made of Cu. When a composite Cu/Ti foil <span class="hlt">deforms</span>, the harder Ti will penetrate into the softer Cu in the convex shapes according to previously reported results. In this paper, we describe the fabrication of multilayer Cu/Ti foils by the roll bonding technique and report our observations. The experimental results lead us to propose a new <span class="hlt">deformation</span> <span class="hlt">mechanism</span> for a hard metal surrounded by a soft metal during rolling of a laminated foil, particularly when the thickness of hard metal foil (Ti, 25 μm) is much less than that of the soft metal foil (Cu, 300 μm). Transmission Electron Microscope (TEM) imaging results show that the hard metal penetrates into the soft metal in the form of concave protrusions. Finite element simulations of the rolling process of a Cu/Ti/Cu composite foil are described. Finally, we focus on an analysis of the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of Ti foils and its effects on grain refinement, and propose a grain refinement <span class="hlt">mechanism</span> from the inside to the outside of the laminates during rolling. PMID:24853192</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22420195','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22420195"><span id="translatedtitle">Scaling laws and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of nanoporous copper under adiabatic uniaxial strain compression</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yuan, Fuping Wu, Xiaolei</p> <p>2014-12-15</p> <p>A series of large-scale molecular dynamics simulations were conducted to investigate the scaling laws and the related atomistic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of Cu monocrystal samples containing randomly placed nanovoids under adiabatic uniaxial strain compression. At onset of yielding, plastic <span class="hlt">deformation</span> is accommodated by dislocations emitted from void surfaces as shear loops. The collapse of voids are observed by continuous emissions of dislocations from void surfaces and their interactions with further plastic <span class="hlt">deformation</span>. The simulation results also suggest that the effect modulus, the yield stress and the energy aborption density of samples under uniaxial strain are linearly proportional to the relative density ρ. Moreover, the yield stress, the average flow stress and the energy aborption density of samples with the same relative density show a strong dependence on the void diameter d, expressed by exponential relations with decay coefficients much higher than -1/2. The corresponding atomistic <span class="hlt">mechanisms</span> for scaling laws of the relative density and the void diameter were also presented. The present results should provide insights for understanding <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of nanoporous metals under extreme conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940008905','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940008905"><span id="translatedtitle">Inelastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in SCS-6/Ti 15-3 MMC lamina under compression</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newaz, Golam M.; Majumdar, Bhaskar S.</p> <p>1993-01-01</p> <p>An investigation was undertaken to study the inelastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in (0)(sub 8) and (90)(sub 8) Ti 15-3/SCS-6 lamina subjected to pure compression. Monotonic tests were conducted at room temperature (RT), 538 C and 650 C. Results indicate that <span class="hlt">mechanical</span> response and <span class="hlt">deformation</span> characteristics were different in monotonic tension and compression loading whereas some of those differences could be attributed to residual stress effects. There were other differences because of changes in damage and failure modes. The inelastic <span class="hlt">deformation</span> in the (0)(sub 8) lamina under compression was controlled primarily by matrix plasticity, although some evidence of fiber-matrix debonding was observed. Failure of the specimen in compression was due to fiber buckling in a macroscopic shear zone (the failure plane). The inelastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> under compression in (90)(sub 8) lamina were controlled by radial fiber fracture, matrix plasticity, and fiber-matrix debonding. The radial fiber fracture was a new damage mode observed for MMC's. Constitutive response was predicted for both the (0)(sub 8) and (90)(sub 8) laminae, using AGLPLY, METCAN, and Battelle's Unit Cell FEA model. Results from the analyses were encouraging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4653952','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4653952"><span id="translatedtitle">Influence of cross-link structure, density and <span class="hlt">mechanical</span> properties in the mesoscale <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of collagen fibrils</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Depalle, Baptiste; Qin, Zhao; Shefelbine, Sandra J.; Buehler, Markus J.</p> <p>2015-01-01</p> <p>Collagen is a ubiquitous protein with remarkable <span class="hlt">mechanical</span> properties. It is highly elastic, shows large fracture strength and enables substantial energy dissipation during <span class="hlt">deformation</span>. Most of the connective tissue in humans consists of collagen fibrils composed of a staggered array of tropocollagen molecules, which are connected by intermolecular cross-links. In this study, we report a three-dimensional coarse-grained model of collagen and analyze the influence of enzymatic cross-links on the <span class="hlt">mechanics</span> of collagen fibrils. Two representatives immature and mature cross-links are implemented in the mesoscale model using a bottom-up approach. By varying the number, type and <span class="hlt">mechanical</span> properties of cross-links in the fibrils and performing tensile test on the models, we systematically investigate the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of cross-linked collagen fibrils. We find that cross-linked fibrils exhibit a three phase behavior, which agrees closer with experimental results than what was obtained using previous models. The fibril <span class="hlt">mechanical</span> response is characterized by: (i) an initial elastic <span class="hlt">deformation</span> corresponding to the collagen molecule uncoiling, (ii) a linear regime dominated by molecule sliding and (iii) the second stiffer elastic regime related to the stretching of the backbone of the tropocollagen molecules until the fibril ruptures. Our results suggest that both cross-link density and type dictate the stiffness of large <span class="hlt">deformation</span> regime by increasing the number of interconnected molecules while cross-links <span class="hlt">mechanical</span> properties determine the failure strain and strength of the fibril. These findings reveal that cross-links play an essential role in creating an interconnected fibrillar material of tunable toughness and strength. PMID:25153614</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JAP...103h3508Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JAP...103h3508Z"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> and damage in α-alumina under hypervelocity impact loading</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Cheng; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Branicio, Paulo S.</p> <p>2008-04-01</p> <p><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in α-alumina under hypervelocity impact are investigated using molecular dynamics simulations containing 540×106 atoms. A cylindrical projectile impacting normal to the (0001) surface at 18km/s generates large temperature and pressure gradients around the impact face, and consequently local amorphization of the substrate in a surrounding hemispherical region is produced. Away from the impact face, a wide range of <span class="hlt">deformations</span> emerge and disappear as a function of time under the influence of local stress fields, e.g., basal and pyramidal slips and basal and rhombohedral twins, all of which show good agreement with the experimental and theoretical results. New <span class="hlt">deformation</span> modes are observed, such as twins along {01¯11}, which propagate at a roughly constant speed of 8km/s and nucleate a large amount of defects where subsequent fractures initiate. The relation between <span class="hlt">deformation</span> patterns and local stress levels is investigated. During unloading, we observe that microcracks nucleate extensively at the intersections of previous <span class="hlt">deformations</span> within an hourglass-shaped volume that connects top and bottom free surfaces. From the simulation, the fracture toughness of alumina is estimated to be 2.0±0.5MPa√m. The substrate eventually fails along the surface of the hourglass region during spallation when clusters of substrate material are ejected from both free surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910004008','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910004008"><span id="translatedtitle">Plastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in polyimide resins and their semi-interpenetrating networks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jang, Bor Z.</p> <p>1990-01-01</p> <p>High-performance thermoset resins and composites are critical to the future growth of space, aircraft, and defense industries in the USA. However, the processing-structure-property relationships in these materials remain poorly understood. In the present ASEE/NASA Summer Research Program, the plastic <span class="hlt">deformation</span> modes and toughening <span class="hlt">mechanisms</span> in single-phase and multiphase thermoset resins were investigated. Both thermoplastic and thermoset polyimide resins and their interpenetrating networks (IPNs and semi-IPNs) were included. The fundamental tendency to undergo strain localization (crazing and shear banding) as opposed to a more diffuse (or homogeneous) <span class="hlt">deformation</span> in these polymers were evaluated. Other possible toughening <span class="hlt">mechanisms</span> in multiphase thermoset resins were also examined. The topological features of network chain configuration/conformation and the multiplicity of phase morphology in INPs and semi-IPNs provide unprecedented opportunities for studying the toughening <span class="hlt">mechanisms</span> in multiphase thermoset polymers and their fiber composites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdSpR..56.2515L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdSpR..56.2515L"><span id="translatedtitle">A <span class="hlt">mechanical</span> model for <span class="hlt">deformable</span> and mesh pattern wheel of lunar roving vehicle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liang, Zhongchao; Wang, Yongfu; Chen, Gang (Sheng); Gao, Haibo</p> <p>2015-12-01</p> <p>As an indispensable tool for astronauts on lunar surface, the lunar roving vehicle (LRV) is of great significance for manned lunar exploration. An LRV moves on loose and soft lunar soil, so the <span class="hlt">mechanical</span> property of its wheels directly affects the mobility performance. The wheels used for LRV have <span class="hlt">deformable</span> and mesh pattern, therefore, the existing <span class="hlt">mechanical</span> theory of vehicle wheel cannot be used directly for analyzing the property of LRV wheels. In this paper, a new <span class="hlt">mechanical</span> model for LRV wheel is proposed. At first, a <span class="hlt">mechanical</span> model for a rigid normal wheel is presented, which involves in multiple conventional parameters such as vertical load, tangential traction force, lateral force, and slip ratio. Secondly, six equivalent coefficients are introduced to amend the rigid normal wheel model to fit for the wheels with <span class="hlt">deformable</span> and mesh-pattern in LRV application. Thirdly, the values of the six equivalent coefficients are identified by using experimental data obtained in an LRV's single wheel testing. Finally, the identified <span class="hlt">mechanical</span> model for LRV's wheel with <span class="hlt">deformable</span> and mesh pattern are further verified and validated by using additional experimental results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4646795','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4646795"><span id="translatedtitle">Dislocation-accommodated grain boundary sliding as the major <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of olivine in the Earth’s upper mantle</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ohuchi, Tomohiro; Kawazoe, Takaaki; Higo, Yuji; Funakoshi, Ken-ichi; Suzuki, Akio; Kikegawa, Takumi; Irifune, Tetsuo</p> <p>2015-01-01</p> <p>Understanding the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of olivine is important for addressing the dynamic processes in Earth’s upper mantle. It has been thought that dislocation creep is the dominant <span class="hlt">mechanism</span> because of extrapolated laboratory data on the plasticity of olivine at pressures below 0.5 GPa. However, we found that dislocation-accommodated grain boundary sliding (DisGBS), rather than dislocation creep, dominates the <span class="hlt">deformation</span> of olivine under middle and deep upper mantle conditions. We used a <span class="hlt">deformation</span>-DIA apparatus combined with synchrotron in situ x-ray observations to study the plasticity of olivine aggregates at pressures up to 6.7 GPa (that is, ~200-km depth) and at temperatures between 1273 and 1473 K, which is equivalent to the conditions in the middle region of the upper mantle. The creep strength of olivine <span class="hlt">deforming</span> by DisGBS is apparently less sensitive to pressure because of the competing pressure-hardening effect of the <span class="hlt">activation</span> volume and pressure-softening effect of water fugacity. The estimated viscosity of olivine controlled by DisGBS is independent of depth and ranges from 1019.6 to 1020.7 Pa·s throughout the asthenospheric upper mantle with a representative water content (50 to 1000 parts per million H/Si), which is consistent with geophysical viscosity profiles. Because DisGBS is a grain size–sensitive creep <span class="hlt">mechanism</span>, the evolution of the grain size of olivine is an important process controlling the dynamics of the upper mantle. PMID:26601281</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18..173Z&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18..173Z&link_type=ABSTRACT"><span id="translatedtitle">Comparison of <span class="hlt">deformation</span> <span class="hlt">mechanics</span> for two different carbonates: oolitic limestone and laminites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zihms, Stephanie; Lewis, Helen; Couples, Gary; Hall, Stephen; Somerville, Jim</p> <p>2016-04-01</p> <p>Carbonate rocks form under a range of conditions which leads to a diverse rock group. Even though carbonates are overall mineralogically simple, the solid-space distribution ranges from simple compositions such as oolitic limestones to highly complex networks of pores and solids as seen in coquinas. Their fundamental <span class="hlt">mechanical</span> behaviour has been identified to be like clastic rocks (Vajdova 2004, Brantut, Heap et al. 2014). However it is very likely that this observation is not true for more complex carbonates. Triaxial tests were performed on cylindrical samples of two different carbonates; a) oolitic limestone (Bicqueley quarry, France) and b) laminite (Ariripe basin, Brazil). The samples were <span class="hlt">deformed</span> under confining pressures of 8, 12 and 20MPa, and 20, 30 and 40MPa, respectively. All tests were stopped as soon as peak load was observed to preserve as many <span class="hlt">deformation</span> characteristics as possible. Photographs of the samples were taken before and after <span class="hlt">deformation</span> to allow surface analysis of <span class="hlt">deformation</span> features. Additionally, samples were analysed post-<span class="hlt">deformation</span> with X-ray tomography (XRT) (using the Zeiss XRadia XRM 520 at the 4D Imaging Lab at Lund University). The 3D tomography images represent the post-<span class="hlt">deformation</span> samples' density distribution, allowing detailed, non-destructive, 3D analysis of the <span class="hlt">deformation</span> features that developed in the triaxial testing, including the complex geometries and interactions of fractures, <span class="hlt">deformation</span> bands and sedimentary layering. They also provide an insight into the complexity of <span class="hlt">deformation</span> features produced due to the carbonate response. Initial results show that the oolitic limestone forms single shear bands almost the length of the sample, exhibiting similar characteristics to sandstones <span class="hlt">deformed</span> under similar conditions. These features are observed for all three applied loads. The laminate sample <span class="hlt">deformed</span> at the lowest confining pressure exhibits compactive features. However, the laminite samples <span class="hlt">deformed</span> at the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21516756','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21516756"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Tube Billets from Zr-1%Nb Alloy under Radial Forging</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Perlovich, Yuriy; Isaenkova, Margarita; Fesenko, Vladimir; Krymskaya, Olga; Zavodchikov, Alexander</p> <p>2011-05-04</p> <p>Features of the <span class="hlt">deformation</span> process by cold radial forging of tube billets from Zr-1%Nb alloy were reconstructed on the basis of X-ray data concerning their structure and texture. The cold radial forging intensifies grain fragmentation in the bulk of billet and increases significantly the latent hardening of potentially <span class="hlt">active</span> slip systems, so that operation only of the single slip system becomes possible. As a result, in radially-forged billets unusual <span class="hlt">deformation</span> and recrystallization textures arise. These textures differ from usual textures of {alpha}-Zr by the mutual inversion of crystallographic axes, aligned along the axis of tube.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012MS%26E...35a2008R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012MS%26E...35a2008R"><span id="translatedtitle"><span class="hlt">Mechanical</span> and microstructural aspects of severe plastic <span class="hlt">deformation</span> of austenitic steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rodak, K.; Pawlicki, J.; Tkocz, M.</p> <p>2012-05-01</p> <p>The paper presents the effects of severe plastic <span class="hlt">deformation</span> by multiple compression in the orthogonal directions on the microstructure and the <span class="hlt">mechanical</span> properties of austenitic steel. Several <span class="hlt">deformation</span> variants were conducted with different number of passes. FEM simulations were performed in order to evaluate the actual values of the effective strain in the examined, central parts of the compressed samples. The <span class="hlt">deformed</span> microstructure was investigated by means of the scanning transmission electron microscopy (STEM) and the scanning electron microscopy (SEM) supported by the electron back scattered diffraction (EBSD). X-ray phase analysis was performed to evaluate the martensite volume fraction. The <span class="hlt">mechanical</span> properties were determined by means of the digital image correlation method and hardness testing. It is shown that the applied forming technique leads to strong grain refinement in the austenitic steel. Moreover, <span class="hlt">deformation</span> induces the martensitic γ- α' transformation. The microstructural changes cause an improvement in the strength properties. The material exhibits the ultimate tensile strength of 1560 MPa and the yield stress of 1500 MPa after reaching the effective strain of 10.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1211501','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1211501"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> of a Lithium-Metal Anode Due to a Very Stiff Separator</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ferrese, A; Newman, J</p> <p>2014-05-21</p> <p>This work builds on the two-dimensional model presented by Ferrese et al. [J. Electrochem. Soc., 159, A1615 (2012)1, which captures the movement of lithium metal at the negative electrode during cycling in a Li-metal/LiCoO2 cell. In this paper, the separator is modeled as a dendrite-inhibiting polymer separator with an elastic modulus of 16 GPa. The separator resists the movement of lithium through the generation of stresses in the cell. These stresses affect the negative electrode through two <span class="hlt">mechanisms</span> altering the thermodynamics of the negative electrode and <span class="hlt">deforming</span> the negative electrode <span class="hlt">mechanically</span>. From this analysis, we find that the dendrite-inhibiting separator causes plastic and elastic <span class="hlt">deformation</span> of the lithium at the negative electrode which flattens the electrode considerably when compared to the liquid-electrolyte case. This flattening of the negative electrode causes only very slight differences in the local state of charge in the positive electrode. When comparing the magnitude of the effects flattening the negative electrode, we find that the plastic <span class="hlt">deformation</span> plays a much larger role than either the pressure-modified reaction kinetics or elastic <span class="hlt">deformation</span>. This is due to the low yield strength of the lithium metal, which limits the stresses such that they have only a small effect on the reaction kinetics. (C) 2014 The Electrochemical Society. All rights reserved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22410266','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22410266"><span id="translatedtitle">Temperature-dependent <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of silicon at the nanoscale: Phase transformation versus defect propagation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kiran, M. S. R. N. Tran, T. T.; Smillie, L. A.; Subianto, D.; Williams, J. S.; Bradby, J. E.; Haberl, B.</p> <p>2015-05-28</p> <p>This study uses high-temperature nanoindentation coupled with in situ electrical measurements to investigate the temperature dependence (25–200 °C) of the phase transformation behavior of diamond cubic (dc) silicon at the nanoscale. Along with in situ indentation and electrical data, ex situ characterizations, such as Raman and cross-sectional transmission electron microscopy, have been used to reveal the indentation-induced <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. We find that phase transformation and defect propagation within the crystal lattice are not mutually exclusive <span class="hlt">deformation</span> processes at elevated temperature. Both can occur at temperatures up to 150 °C but to different extents, depending on the temperature and loading conditions. For nanoindentation, we observe that phase transformation is dominant below 100 °C but that <span class="hlt">deformation</span> by twinning along (111) planes dominates at 150 °C and 200 °C. This work, therefore, provides clear insight into the temperature dependent <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in dc-Si at the nanoscale and helps to clarify previous inconsistencies in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016PhLA..380.2279B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016PhLA..380.2279B"><span id="translatedtitle">Perturbatively <span class="hlt">deformed</span> defects in Pöschl-Teller-driven scenarios for quantum <span class="hlt">mechanics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bernardini, Alex E.; da Rocha, Roldão</p> <p>2016-07-01</p> <p>Pöschl-Teller-driven solutions for quantum <span class="hlt">mechanical</span> fluctuations are triggered off by single scalar field theories obtained through a systematic perturbative procedure for generating <span class="hlt">deformed</span> defects. The analytical properties concerning the quantum fluctuations in one-dimension, zero-mode states, first- and second-excited states, and energy density profiles are all obtained from <span class="hlt">deformed</span> topological and non-topological structures supported by real scalar fields. Results are firstly derived from an integrated λϕ4 theory, with corresponding generalizations applied to starting λχ4 and sine-Gordon theories. By focusing our calculations on structures supported by the λϕ4 theory, the outcome of our study suggests an exact quantitative correspondence to Pöschl-Teller-driven systems. Embedded into the perturbative quantum <span class="hlt">mechanics</span> framework, such a correspondence turns into a helpful tool for computing excited states and continuous mode solutions, as well as their associated energy spectrum, for quantum fluctuations of perturbatively <span class="hlt">deformed</span> structures. Perturbative <span class="hlt">deformations</span> create distinct physical scenarios in the context of exactly solvable quantum systems and may also work as an analytical support for describing novel braneworld universes embedded into a 5-dimensional gravity bulk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999MMTA...30..845P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999MMTA...30..845P"><span id="translatedtitle"><span class="hlt">Mechanical</span> behavior of Al-Li-SiC composites: Part I. Microstructure and tensile <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poza, P.; Llorca, J.</p> <p>1999-03-01</p> <p>The microstructure and tensile properties of an 8090 Al-Li alloy reinforced with 15 vol pet SiC particles were investigated, together with those of the unreinforced alloy processed following the same route. Two different heat treatments (naturally aged at ambient temperature and artificially aged at elevated temperature to the peak strength) were chosen because they lead to very different behaviors. Special emphasis was given to the analysis of the differences and similarities in the microstructure and in the <span class="hlt">deformation</span> and failure <span class="hlt">mechanisms</span> between the composite and the unreinforced alloy. It was found that the dispersion of the SiC particles restrained the formation of elongated grains during extrusion and inhibited the precipitation of Al3Li at ambient temperature. The <span class="hlt">deformation</span> processes in the peak-aged materials were controlled by the S' precipitates, which acted as barriers for dislocation motion and homogenized the slip. Homogeneous slip was also observed in the naturally aged composite, but not in the unreinforced alloy, where plastic <span class="hlt">deformation</span> was concentrated in slip bands. The most notorious differences between the alloy and the composite were found in the fracture <span class="hlt">mechanisms</span>. The naturally aged unreinforced alloy failed by transgranular shear, while the failure of the peak-aged alloy was induced by grain-boundary fracture. The fracture of the composite in both tempers was, however, precipitated by the progressive fracture of the SiC reinforcements during <span class="hlt">deformation</span>, which led to the early failure at the onset of plastic instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70013794','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70013794"><span id="translatedtitle"><span class="hlt">Deformation</span> of clinopyroxenite: evidence for a transition in flow <span class="hlt">mechanisms</span> and semibrittle behavior.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Kirby, S.H.; Kronenberg, A.K.</p> <p>1984-01-01</p> <p>A systematic suite of constant strain rate experiments was performed on a vacuum-dried, high-purity, fine-grained clinopyroxenite using NaCl and NaF as confining media in a Griggs-type piston-cylinder apparatus. The experiments were carried out over a range of temperatures from 400o to 1100oC, strain rates from 10-3 to 10-7 s-1, and confining pressures from 170 to 1990 MPa. At T = 600oC and 8e = 1.1 X 10-5 s-1, 3 modes of <span class="hlt">deformation</span> occur with increasing confining pressure. In experiments at P = 1500 MPa, 2 regimes of flow are clearly defined. The flow data within each regime can be satisfactorily fitted to thermally <span class="hlt">activated</span> power laws. We believe that the parameters reflect flow dominated by the kinetics of dislocation glide associated with <span class="hlt">mechanical</span> twinning and (100) slip in the low temperature regime and creep by multiple slip accompanied by increased rates of diffusion and recovery in the high temperature regime. -after Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AIPC.1233..328Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AIPC.1233..328Z"><span id="translatedtitle">A Computational Study of Plastic <span class="hlt">Deformation</span> in AISI 304 Induced by Surface <span class="hlt">Mechanical</span> Attrition Treatment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, X. C.; Lu, J.; Shi, S. Q.</p> <p>2010-05-01</p> <p>As a technique of grain refinement process by plastic <span class="hlt">deformation</span>, surface <span class="hlt">mechanical</span> attrition treatment (SMAT) has been developed to be one of the most effective ways to optimize the <span class="hlt">mechanical</span> properties of various materials including pure metals and alloys. SMAT can significantly reduce grain size into nanometer regime in the surface layer of bulk materials, providing tremendous opportunities for improving physical, chemical and <span class="hlt">mechanical</span> properties of the materials. In this work, a computational modeling of the surface <span class="hlt">mechanical</span> attrition treatment (SMAT) process is presented, in which Johnson-Cook plasticity model and the finite element method were employed to study the high strain rate, elastic-plastic dynamic process of ball impact on a metallic target. AISI 304 steel with low stacking fault energy was chosen as the target material. First, a random impact model was used to analyze the statistic characteristics of ball impact, and then the plastic <span class="hlt">deformation</span> behavior and residual stress distribution in AISI 304 stainless steel during SMAT were studied. The simulation results show that the compressive residual stress and vertical <span class="hlt">deformation</span> of the surface structures were directly affected by ball impact frequency, incident impact angle and ball diameter used in SMAT process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoJI.201..947R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoJI.201..947R"><span id="translatedtitle">Present-day <span class="hlt">deformation</span> of the Pyrenees revealed by GPS surveying and earthquake focal <span class="hlt">mechanisms</span> until 2011</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rigo, A.; Vernant, P.; Feigl, K. L.; Goula, X.; Khazaradze, G.; Talaya, J.; Morel, L.; Nicolas, J.; Baize, S.; Chéry, J.; Sylvander, M.</p> <p>2015-05-01</p> <p>The Pyrenean mountain range is a slowly <span class="hlt">deforming</span> belt with continuous and moderate seismic <span class="hlt">activity</span>. To quantify its <span class="hlt">deformation</span> field, we present the velocity field estimated from a GPS survey of the Pyrenees spanning 18 yr. The PotSis and ResPyr networks, including a total of 85 GPS sites, were installed and first measured in 1992 and 1995-1997, respectively, and remeasured in 2008 and 2010. We obtain a <span class="hlt">deformation</span> field with velocities less than 1 mm yr-1 across the range. The estimated velocities for individual stations do not differ significantly from zero with 95 per cent confidence. Even so, we estimate a maximum extensional horizontal strain rate of 2.0 ± 1.7 nanostrain per year in a N-S direction in the western part of the range. We do not interpret the vertical displacements due to their large uncertainties. In order to compare the horizontal strain rates with the seismic <span class="hlt">activity</span>, we analyse a set of 194 focal <span class="hlt">mechanisms</span> using three methods: (i) the `r' factor relating their P and T axes, (ii) the stress tensors obtained by fault slip inversion and (iii) the strain-rate tensors. Stress and strain-rate tensors are estimated for: (i) the whole data set, (ii) the eastern and western parts of the range separately, and (iii) eight zones, which are defined based on the seismicity and the tectonic patterns of the Pyrenees. Each of these analyses reveals a lateral variation of the <span class="hlt">deformation</span> style from compression and extension in the east to extension and strike-slip in the west of the range. Although the horizontal components of the strain-rate tensors estimated from the seismic data are slightly smaller in magnitude than those computed from the GPS velocity field, they are consistent within the 2σ uncertainties. Furthermore, the orientations of their principal axes agree with the mapped <span class="hlt">active</span> faults.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PhDT........44H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014PhDT........44H&link_type=ABSTRACT"><span id="translatedtitle">Effects of Fault Segmentation, <span class="hlt">Mechanical</span> Interaction, and Structural Complexity on Earthquake-Generated <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Haddad, David Elias</p> <p></p> <p>Earth's topographic surface forms an interface across which the geodynamic and geomorphic engines interact. This interaction is best observed along crustal margins where topography is created by <span class="hlt">active</span> faulting and sculpted by geomorphic processes. Crustal <span class="hlt">deformation</span> manifests as earthquakes at centennial to millennial timescales. Given that nearly half of Earth's human population lives along <span class="hlt">active</span> fault zones, a quantitative understanding of the <span class="hlt">mechanics</span> of earthquakes and faulting is necessary to build accurate earthquake forecasts. My research relies on the quantitative documentation of the geomorphic expression of large earthquakes and the physical processes that control their spatiotemporal distributions. The first part of my research uses high-resolution topographic lidar data to quantitatively document the geomorphic expression of historic and prehistoric large earthquakes. Lidar data allow for enhanced visualization and reconstruction of structures and stratigraphy exposed by paleoseismic trenches. Lidar surveys of fault scarps formed by the 1992 Landers earthquake document the centimeter-scale erosional landforms developed by repeated winter storm-driven erosion. The second part of my research employs a quasi-static numerical earthquake simulator to explore the effects of fault roughness, friction, and structural complexities on earthquake-generated <span class="hlt">deformation</span>. My experiments show that fault roughness plays a critical role in determining fault-to-fault rupture jumping probabilities. These results corroborate the accepted 3-5 km rupture jumping distance for smooth faults. However, my simulations show that the rupture jumping threshold distance is highly variable for rough faults due to heterogeneous elastic strain energies. Furthermore, fault roughness controls spatiotemporal variations in slip rates such that rough faults exhibit lower slip rates relative to their smooth counterparts. The central implication of these results lies in guiding the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1286705','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1286705"><span id="translatedtitle">Characterization of dislocation structures and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in as-grown and <span class="hlt">deformed</span> directionally solidified NiAl–Mo composites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kwon, J.; Bowers, M. L.; Brandes, M. C.; McCreary, V.; Robertson, Ian M.; Phani, P. Sudaharshan; Bei, H.; Gao, Y. F.; Pharr, George M.; George, Easo P.; Mills, M. J.</p> <p>2015-02-26</p> <p>In this paper, directionally solidified (DS) NiAl–Mo eutectic composites were strained to plastic strain values ranging from 0% to 12% to investigate the origin of the previously observed stochastic versus deterministic <span class="hlt">mechanical</span> behaviors of Mo-alloy micropillars in terms of the development of dislocation structures at different pre-strain levels. The DS composites consist of long, [1 0 0] single-crystal Mo-alloy fibers with approximately square cross-sections embedded in a [1 0 0] single-crystal NiAl matrix. Scanning transmission electron microscopy (STEM) and computational stress state analysis were conducted for the current study. STEM of the as-grown samples (without pre-straining) reveal no dislocations in the investigated Mo-alloy fibers. In the NiAl matrix, on the other hand, a(1 0 0)-type dislocations exist in two orthogonal orientations: along the [1 0 0] Mo fiber axis, and wrapped around the fiber axis. They presumably form to accommodate the different thermal contractions of the two phases during cool down after eutectic solidification. At intermediate pre-strain levels (4–8%), a/2(1 1 1)-type dislocations are present in the Mo-alloy fibers and the pre-existing dislocations in the NiAl matrix seem to be swept toward the interphase boundary. Some of the dislocations in the Mo-alloy fibers appear to be transformed from a(1 0 0)-type dislocations present in the NiAl matrix. Subsequently, the transformed dislocations in the fibers propagate through the NiAl matrix as a(1 1 1) dislocations and aid in initiating additional slip bands in adjacent fibers. Thereafter, co-<span class="hlt">deformation</span> presumably occurs by (1 1 1) slip in both phases. With a further increase in the pre-strain level (>10%), multiple a/2(1 1 1)-type dislocations are observed in many locations in the Mo-alloy fibers. Interactions between these systems upon subsequent <span class="hlt">deformation</span> could lead to stable junctions and persistent dislocation sources. Finally, the transition from stochastic to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1286705-characterization-dislocation-structures-deformation-mechanisms-grown-deformed-directionally-solidified-nialmo-composites','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1286705-characterization-dislocation-structures-deformation-mechanisms-grown-deformed-directionally-solidified-nialmo-composites"><span id="translatedtitle">Characterization of dislocation structures and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in as-grown and <span class="hlt">deformed</span> directionally solidified NiAl–Mo composites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Kwon, J.; Bowers, M. L.; Brandes, M. C.; McCreary, V.; Robertson, Ian M.; Phani, P. Sudaharshan; Bei, H.; Gao, Y. F.; Pharr, George M.; George, Easo P.; et al</p> <p>2015-02-26</p> <p>In this paper, directionally solidified (DS) NiAl–Mo eutectic composites were strained to plastic strain values ranging from 0% to 12% to investigate the origin of the previously observed stochastic versus deterministic <span class="hlt">mechanical</span> behaviors of Mo-alloy micropillars in terms of the development of dislocation structures at different pre-strain levels. The DS composites consist of long, [1 0 0] single-crystal Mo-alloy fibers with approximately square cross-sections embedded in a [1 0 0] single-crystal NiAl matrix. Scanning transmission electron microscopy (STEM) and computational stress state analysis were conducted for the current study. STEM of the as-grown samples (without pre-straining) reveal no dislocations inmore » the investigated Mo-alloy fibers. In the NiAl matrix, on the other hand, a(1 0 0)-type dislocations exist in two orthogonal orientations: along the [1 0 0] Mo fiber axis, and wrapped around the fiber axis. They presumably form to accommodate the different thermal contractions of the two phases during cool down after eutectic solidification. At intermediate pre-strain levels (4–8%), a/2(1 1 1)-type dislocations are present in the Mo-alloy fibers and the pre-existing dislocations in the NiAl matrix seem to be swept toward the interphase boundary. Some of the dislocations in the Mo-alloy fibers appear to be transformed from a(1 0 0)-type dislocations present in the NiAl matrix. Subsequently, the transformed dislocations in the fibers propagate through the NiAl matrix as a(1 1 1) dislocations and aid in initiating additional slip bands in adjacent fibers. Thereafter, co-<span class="hlt">deformation</span> presumably occurs by (1 1 1) slip in both phases. With a further increase in the pre-strain level (>10%), multiple a/2(1 1 1)-type dislocations are observed in many locations in the Mo-alloy fibers. Interactions between these systems upon subsequent <span class="hlt">deformation</span> could lead to stable junctions and persistent dislocation sources. Finally, the transition from stochastic to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70029399','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70029399"><span id="translatedtitle">Structural evolution of fault zones in sandstone by multiple <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>: Moab fault, southeast Utah</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Davatzes, N.C.; Eichhubl, P.; Aydin, A.</p> <p>2005-01-01</p> <p>Faults in sandstone are frequently composed of two classes of structures: (1) <span class="hlt">deformation</span> bands and (2) joints and sheared joints. Whereas the former structures are associated with cataclastic <span class="hlt">deformation</span>, the latter ones represent brittle fracturing, fragmentation, and brecciation. We investigated the distribution of these structures, their formation, and the underlying <span class="hlt">mechanical</span> controls for their occurrence along the Moab normal fault in southeastern Utah through the use of structural mapping and numerical elastic boundary element modeling. We found that <span class="hlt">deformation</span> bands occur everywhere along the fault, but with increased density in contractional relays. Joints and sheared joints only occur at intersections and extensional relays. In all locations , joints consistently overprint <span class="hlt">deformation</span> bands. Localization of joints and sheared joints in extensional relays suggests that their distribution is controlled by local variations in stress state that are due to <span class="hlt">mechanical</span> interaction between the fault segments. This interpretation is consistent with elastic boundary element models that predict a local reduction in mean stress and least compressive principal stress at intersections and extensional relays. The transition from <span class="hlt">deformation</span> band to joint formation along these sections of the fault system likely resulted from the combined effects of changes in remote tectonic loading, burial depth, fluid pressure, and rock properties. In the case of the Moab fault, we conclude that the structural heterogeneity in the fault zone is systematically related to the geometric evolution of the fault, the local state of stress associated with fault slip , and the remote loading history. Because the type and distribution of structures affect fault permeability and strength, our results predict systematic variations in these parameters with fault evolution. ?? 2004 Geological Society of America.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ApPhL..76.2868Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ApPhL..76.2868Q"><span id="translatedtitle">Load transfer and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in carbon nanotube-polystyrene composites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qian, D.; Dickey, E. C.; Andrews, R.; Rantell, T.</p> <p>2000-05-01</p> <p>Multiwall carbon nanotubes have been dispersed homogeneously throughout polystyrene matrices by a simple solution-evaporation method without destroying the integrity of the nanotubes. Tensile tests on composite films show that 1 wt % nanotube additions result in 36%-42% and ˜25% increases in elastic modulus and break stress, respectively, indicating significant load transfer across the nanotube-matrix interface. In situ transmission electron microscopy studies provided information regarding composite <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and interfacial bonding between the multiwall nanotubes and polymer matrix.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JOM....68a.136R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JOM....68a.136R"><span id="translatedtitle">In Situ <span class="hlt">Mechanical</span> Testing Techniques for Real-Time Materials <span class="hlt">Deformation</span> Characterization</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rudolf, Chris; Boesl, Benjamin; Agarwal, Arvind</p> <p>2016-01-01</p> <p>In situ <span class="hlt">mechanical</span> property testing has the ability to enhance quantitative characterization of materials by revealing the occurring <span class="hlt">deformation</span> behavior in real time. This article will summarize select recent testing performed inside a scanning electron microscope on various materials including metals, ceramics, composites, coatings, and 3-Dimensional graphene foam. Tensile and indentation testing methods are outlined with case studies and preliminary data. The benefits of performing a novel double-torsion testing technique in situ are also proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/tm13B1','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/tm13B1"><span id="translatedtitle">Modeling crustal <span class="hlt">deformation</span> near <span class="hlt">active</span> faults and volcanic centers: a catalog of <span class="hlt">deformation</span> models and modeling approaches</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Battaglia, Maurizio; Cervelli; Peter, F.; Murray, Jessica R.</p> <p>2013-01-01</p> <p>This manual provides the physical and mathematical concepts for selected models used to interpret <span class="hlt">deformation</span> measurements near <span class="hlt">active</span> faults and volcanic centers. The emphasis is on analytical models of <span class="hlt">deformation</span> that can be compared with data from the Global Positioning System (GPS) receivers, Interferometric synthetic aperture radar (InSAR), leveling surveys, tiltmeters and strainmeters. Source models include pressurized spherical, ellipsoidal, and horizontal penny-shaped geometries in an elastic, homogeneous, flat half-space. Vertical dikes and faults are described following the mathematical notation for rectangular dislocations in an elastic, homogeneous, flat half-space. All the analytical expressions were verified against numerical models developed by use of COMSOL Multyphics, a Finite Element Analysis software (http://www.comsol.com). In this way, typographical errors present were identified and corrected. Matlab scripts are also provided to facilitate the application of these models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanos...8.9234H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016Nanos...8.9234H&link_type=ABSTRACT"><span id="translatedtitle">Quantifying and observing viscoplasticity at the nanoscale: highly localized <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in ultrathin nanocrystalline gold films</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hosseinian, Ehsan; Legros, Marc; Pierron, Olivier N.</p> <p>2016-04-01</p> <p>This study unveils the stress relaxation transient <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in 100 nm-thick, nanocrystalline Au films thanks to a robust quantitative in situ TEM MEMS nanomechanical testing approach to quantify stress relaxation and to perform in situ observations of time-dependent <span class="hlt">deformation</span> in ultrathin nanocrystalline films. The relaxation is characterized by a decrease in plastic strain rate of more than one order of magnitude over the first ~30 minutes (from 10-4 to less than 10-5 s-1). For longer relaxation experiments, the plastic strain rate decreases down to 10-7 s-1 after several hours. The power-law exponent n, relating plastic strain rate and stress, continuously decreases from initial large values (n from 6 to 14 at t = 0) down to low values (n ~ 1-2) after several hours. In situ TEM observations reveal that the relaxation behavior is initially accommodated by highly localized, sustained, intergranular and transgranular dislocation motion. Over time, the dislocation sources become less operative or exhausted, leading to a transition to grain-boundary-diffusion based <span class="hlt">mechanisms</span>. The results also highlight a promising technique for nanoscale characterization of time-dependent <span class="hlt">deformation</span>.This study unveils the stress relaxation transient <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in 100 nm-thick, nanocrystalline Au films thanks to a robust quantitative in situ TEM MEMS nanomechanical testing approach to quantify stress relaxation and to perform in situ observations of time-dependent <span class="hlt">deformation</span> in ultrathin nanocrystalline films. The relaxation is characterized by a decrease in plastic strain rate of more than one order of magnitude over the first ~30 minutes (from 10-4 to less than 10-5 s-1). For longer relaxation experiments, the plastic strain rate decreases down to 10-7 s-1 after several hours. The power-law exponent n, relating plastic strain rate and stress, continuously decreases from initial large values (n from 6 to 14 at t = 0) down to low values (n ~ 1-2) after</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......304D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......304D"><span id="translatedtitle">On The Creep Behavior and <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> Found in an Advanced Polycrystalline Nickel-Base Superalloy at High Temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Deutchman, Hallee Zox</p> <p></p> <p>Polycrystalline Ni-base superalloys are used as turbine disks in the hot section in jet engines, placing them in a high temperature and stress environment. As operating temperatures increase in search of better fuel efficiency, it becomes important to understand how these higher temperatures are affecting <span class="hlt">mechanical</span> behavior and <span class="hlt">active</span> <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in the substructure. Not only are operating temperatures increasing, but there is a drive to design next generation alloys in shorter time periods using predictive modeling capabilities. This dissertation focuses on <span class="hlt">mechanical</span> behavior and <span class="hlt">active</span> <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> found in two different advanced polycrystalline alloy systems, information which will then be used to build advanced predictive models to design the next generation of alloys. The first part of this dissertation discusses the creep behavior and identifying <span class="hlt">active</span> <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in an advanced polycrystalline Ni-based superalloy (ME3) that is currently in operation, but at higher temperatures and stresses than are experienced in current engines. Monotonic creep tests were run at 700°C and between 655-793MPa at 34MPa increments, on two microstructures (called M1 and M2) produced by different heat treatments. All tests were crept to 0.5% plastic strain. Transient temperature and transient stress tests were used determine <span class="hlt">activation</span> energy and stress exponents of the M1 microstructure. Constant strain rate tests (at 10-4s-1) were performed on both microstructures as well. Following creep testing, both M1 and M2 microstructures were fully characterized using Scanning Electron Microscopy (SEM) for basic microstructure information, and Scanning Transmission Electron Microscopy (STEM) to determine <span class="hlt">active</span> <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. It was found that in the M1 microstructure, reorder mediated <span class="hlt">activity</span> (such as discontinuous faulting and microtwinning) is dominant at low stresses (655-724 MPa). Dislocations in the gamma matrix, and overall planar</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/10646945','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/10646945"><span id="translatedtitle">The relationship between the clinical performance and large <span class="hlt">deformation</span> <span class="hlt">mechanical</span> behavior of retrieved UHMWPE tibial inserts.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kurtz, S M; Rimnac, C M; Pruitt, L; Jewett, C W; Goldberg, V; Edidin, A A</p> <p>2000-02-01</p> <p>Many aspects of the proposed relationship between material properties and clinical performance of UHMWPE components remain unclear. In this study, we explored the hypothesis that the clinical performance of tibial inserts is directly related to its large-<span class="hlt">deformation</span> <span class="hlt">mechanical</span> behavior measured near the articulating surface. Retrieval analysis was performed on three conventional UHMWPE and three Hylamer-M tibial components of the same design and manufacturer. Samples of material were then obtained from the worn regions of each implant and subjected to <span class="hlt">mechanical</span> characterization using the small punch test. Statistically significant relationships were observed between the metrics of the small punch test and the total damage score and the burnishing damage score of the implants. We also examined the near-surface morphology of the retrievals using transmission electron microscopy. TEM analysis revealed lamellar alignment at and below the wear surfaces of the conventional UHMWPE retrievals up to a maximum depth of approximately 8 microm, consistent with large-<span class="hlt">deformation</span> crystalline plasticity. The depth of the plasticity-induced damage layer varied not only between the retrievals, but also between the conventional UHMWPE and Hylamer-M components. Thus, the results of this study support the hypothesis that the clinical performance of UHMWPE tibial inserts is related to the large-<span class="hlt">deformation</span> <span class="hlt">mechanical</span> behavior measured near the articulating surface. PMID:10646945</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Tectp.653...95D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Tectp.653...95D"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> and seismicity in the Southern Alps (Italy): The Montello hill as a case study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Danesi, Stefania; Pondrelli, Silvia; Salimbeni, Simone; Cavaliere, Adriano; Serpelloni, Enrico; Danecek, Peter; Lovati, Sara; Massa, Marco</p> <p>2015-06-01</p> <p>The Montello anticline is a morphotectonic feature of the east pede-mountain of the South Alpine Chain in northern Italy, which lies ca. 40 km northwest of Venice, Italy. The purpose of this study is to characterize the present-day crustal <span class="hlt">deformation</span> and seismotectonics of the Montello area through multi-parametric geophysical observations. We used new data obtained from the installation of a temporary network of 12 seismic stations and 6 GPS sites. The GPS observations indicate that there is ~ 1 mm/yr shortening across the Montello thrust. Sites located north of the Montello thrust front deviate from the ~ NNW-ward Adria-Eurasia convergence direction, as they are constrained by a relative rotation pole in northwestern Italy that has a NNE-ward motion trend. Over 18 months, seismographic recordings allowed us to locate 142 local seismic events with Ml 0.5-3.5 with good reliability (rms < 0.5). After cross-correlation analysis, we classified 42 of these events into six clusters, with cross-correlation thresholds > 0.80. The source focal solutions indicate that: (i) there is thrusting seismic <span class="hlt">activity</span> on the basal, sub-horizontal, portion of the Montello structure; and (ii) strike-slip source kinematics prevail on the western edge of the Montello hill. Our observations on the source <span class="hlt">mechanisms</span> and the measured crustal <span class="hlt">deformation</span> confirm that the Montello thrust is tectonically <span class="hlt">active</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22162977','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22162977"><span id="translatedtitle">Size effects of primary/secondary twins on the atomistic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in hierarchically nanotwinned metals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yuan, Fuping; Wu, Xiaolei</p> <p>2013-05-28</p> <p>A series of large-scale molecular dynamics simulations have been performed to investigate the tensile properties of nanotwinned (NT) copper with hierarchically twinned structures (HTS). For the same grain size d and the same spacing of primary twins {lambda}{sub 1}, the average flow stress first increases as the spacing of secondary twins {lambda}{sub 2} decreases, reaching a maximum at a critical {lambda}{sub 2}, and then decreases as {lambda}{sub 2} becomes even smaller. The smaller the spacing for {lambda}{sub 1}, the smaller the critical spacing for {lambda}{sub 2}. There exists a transition in dominating <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, occurring at a critical spacing of {lambda}{sub 2} for which strength is maximized. Above the critical spacing of {lambda}{sub 2}, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are dominated by the two Hall-Petch type strengthening <span class="hlt">mechanisms</span>: (a) partial dislocations emitted from grain boundaries (GBs) travel across other GBs and twin boundaries (TBs); (b) partial dislocations emitted from TBs travel across other TBs. Below the critical spacing of {lambda}{sub 2}, the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> is dominated by the two softening <span class="hlt">mechanisms</span>: (a) Partial dislocations emitted from boundaries of the primary twins travel parallel to the TBs of the secondary twins, leading to detwinning of the secondary twins; (b) Boundaries of the primary twins shift entirely, leading to thickening in one part of primary twins and thinning in the other part of primary twins. The present results should provide insights to design the microstructures for reinforcing the <span class="hlt">mechanical</span> properties in the NT metals with HTS.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T21H..05M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T21H..05M"><span id="translatedtitle">Melt Impregnation, Strain Localization, and <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in a Fossil Oceanic Fracture Zone (Ingalls Ophiolite)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Miller, R. B.; Gordon, S. M.</p> <p>2010-12-01</p> <p>A steep mantle shear zone that <span class="hlt">deforms</span> ultramafic rocks of the Jurassic Ingalls ophiolite is inferred to preserve a record of the interplay of melt impregnation, strain localization, and switching <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in a fossil oceanic fracture zone. This ~2-km-wide, E-W-striking shear zone separates harzburgite and dunite on the south from lherzolite and cpx-rich harzburgite on the north. Geochemical data from the lherzolite, which contains veinlets of plagioclase and cpx, suggest impregnation by infiltrating basaltic melt. The shear zone reworks the lherzolite unit, but also contains widespread plagioclase peridotite and hornblende peridotite, and shear-zone mylonites are less depleted than the adjacent units. Olivine is reduced in average grain size from 1.5-3.0 mm in the lherzolites to 50 µm in some mylonites. In the mylonites, opx and cpx porphyroclasts are set in a mosaic of olivine, cpx, opx +/- hornblende +/- plagioclase. Lattice preferred orientations (LPO) determined by EBSD indicate that olivine in the dunite-harzburgite and lherzolite units <span class="hlt">deformed</span> by glide on [100] (010), a common <span class="hlt">mechanism</span> for dislocation creep in the upper mantle. In contrast, olivine in the mylonites has much weaker, poorly defined LPOs. This weakening of the LPO and the microstructures are compatible with dynamic recrystallization and grain-size reduction resulting from dislocation creep leading to a change to a grain-size-sensitive <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. We suggest that impregnation by infiltrating melts may have helped localize strain, and the formation of multiple phases, in part as a result of impregnation, may have stabilized the small olivine grain size.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPA....5h7120L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPA....5h7120L"><span id="translatedtitle">Atomistic tensile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of Fe with gradient nano-grained structure</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Wenbin; Yuan, Fuping; Wu, Xiaolei</p> <p>2015-08-01</p> <p>Large-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic <span class="hlt">deformation</span> stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are closely related to the grain sizes. For grains with d = 25 nm, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22492300','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22492300"><span id="translatedtitle">Atomistic tensile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of Fe with gradient nano-grained structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, Wenbin E-mail: xlwu@imech.ac.cn; Yuan, Fuping Wu, Xiaolei E-mail: xlwu@imech.ac.cn</p> <p>2015-08-15</p> <p>Large-scale molecular dynamics (MD) simulations have been performed to investigate the tensile properties and the related atomistic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of the gradient nano-grained (GNG) structure of bcc Fe (gradient grains with d from 25 nm to 105 nm), and comparisons were made with the uniform nano-grained (NG) structure of bcc Fe (grains with d = 25 nm). The grain size gradient in the nano-scale converts the applied uniaxial stress to multi-axial stresses and promotes the dislocation behaviors in the GNG structure, which results in extra hardening and flow strength. Thus, the GNG structure shows slightly higher flow stress at the early plastic <span class="hlt">deformation</span> stage when compared to the uniform NG structure (even with smaller grain size). In the GNG structure, the dominant <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are closely related to the grain sizes. For grains with d = 25 nm, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> are dominated by GB migration, grain rotation and grain coalescence although a few dislocations are observed. For grains with d = 54 nm, dislocation nucleation, propagation and formation of dislocation wall near GBs are observed. Moreover, formation of dislocation wall and dislocation pile-up near GBs are observed for grains with d = 105 nm, which is the first observation by MD simulations to our best knowledge. The strain compatibility among different layers with various grain sizes in the GNG structure should promote the dislocation behaviors and the flow stress of the whole structure, and the present results should provide insights to design the microstructures for developing strong-and-ductile metals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12702870','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12702870"><span id="translatedtitle">Multifunctional Alloys Obtained via a Dislocation-Free Plastic <span class="hlt">Deformation</span> <span class="hlt">Mechanism</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Saito, Takashi; Furuta, Tadahiko; Hwang, Jung-Hwan; Kuramoto, Shigeru; Nishino, Kazuaki; Suzuki, Nobuaki; Chen, Rong; Yamada, Akira; Ito, Kazuhiko; Seno, Yoshiki; Nonaka, Takamasa; Ikehata, Hideaki; Nagasako, Naoyuki; Iwamoto, Chihiro; Ikuhara, Yuuichi; Sakuma, Taketo</p> <p>2003-04-18</p> <p>We describe a group of alloys that exhibit "super" properties, such as ultralow elastic modulus, ultrahigh strength, super elasticity, and super plasticity, at room temperature and that show Elinvar and Invar behavior. These "super" properties are attributable to a dislocation-free plastic <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. In cold-worked alloys, this <span class="hlt">mechanism</span> forms elastic strain fields of hierarchical structure that range in size from the nanometer scale to several tens of micrometers. The resultant elastic strain energy leads to a number of enhanced material properties. PMID:12702870</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27087395','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27087395"><span id="translatedtitle">Quantifying and observing viscoplasticity at the nanoscale: highly localized <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in ultrathin nanocrystalline gold films.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hosseinian, Ehsan; Legros, Marc; Pierron, Olivier N</p> <p>2016-04-28</p> <p>This study unveils the stress relaxation transient <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in 100 nm-thick, nanocrystalline Au films thanks to a robust quantitative in situ TEM MEMS nanomechanical testing approach to quantify stress relaxation and to perform in situ observations of time-dependent <span class="hlt">deformation</span> in ultrathin nanocrystalline films. The relaxation is characterized by a decrease in plastic strain rate of more than one order of magnitude over the first ∼30 minutes (from 10(-4) to less than 10(-5) s(-1)). For longer relaxation experiments, the plastic strain rate decreases down to 10(-7) s(-1) after several hours. The power-law exponent n, relating plastic strain rate and stress, continuously decreases from initial large values (n from 6 to 14 at t = 0) down to low values (n ∼ 1-2) after several hours. In situ TEM observations reveal that the relaxation behavior is initially accommodated by highly localized, sustained, intergranular and transgranular dislocation motion. Over time, the dislocation sources become less operative or exhausted, leading to a transition to grain-boundary-diffusion based <span class="hlt">mechanisms</span>. The results also highlight a promising technique for nanoscale characterization of time-dependent <span class="hlt">deformation</span>. PMID:27087395</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JMiMi..24g5003M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JMiMi..24g5003M"><span id="translatedtitle">Clear evidence of <span class="hlt">mechanical</span> <span class="hlt">deformation</span> in RF-MEMS switches during prolonged actuation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mulloni, V.; Resta, G.; Margesin, B.</p> <p>2014-07-01</p> <p>Dielectric charging is normally considered one of the most important problems when dealing with RF-MEMS switch reliability, especially for applications which require long-term operation. Other important effects are therefore often neglected. In this paper we demonstrate that, for the case of long-term actuation in dielectric-less switches, the most important issue for switch reliability is not dielectric charging but viscoelastic <span class="hlt">deformation</span> and creep of the mobile membrane. The measurements and the analysis are performed both for a cantilever and for a clamped-clamped switch configuration, evidencing that in the first case the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> are more pronounced, and that they can justify almost completely the variation of actuation and release voltage experimentally measured. <span class="hlt">Mechanical</span> <span class="hlt">deformation</span> is also detected in a clamped-clamped switch, but it is less evident than that in the previous case. Nonetheless, even in this case they are responsible for most of the actuation and de-actuation voltage change experimentally detected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24626769','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24626769"><span id="translatedtitle">Image-based <span class="hlt">mechanical</span> analysis of stent <span class="hlt">deformation</span>: concept and exemplary implementation for aortic valve stents.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gessat, Michael; Hopf, Raoul; Pollok, Thomas; Russ, Christoph; Frauenfelder, Thomas; Sündermann, Simon Harald; Hirsch, Sven; Mazza, Edoardo; Székely, Gábor; Falk, Volkmar</p> <p>2014-01-01</p> <p>An approach for extracting the radial force load on an implanted stent from medical images is proposed. To exemplify the approach, a system is presented which computes a radial force estimation from computer tomography images acquired from patients who underwent transcatheter aortic valve implantation (TAVI). The <span class="hlt">deformed</span> shape of the implanted valve prosthesis' Nitinol frame is extracted from the images. A set of displacement vectors is computed that parameterizes the observed <span class="hlt">deformation</span>. An iterative relaxation algorithm is employed to adapt the information extracted from the images to a finite-element model of the stent, and the radial components of the interaction forces between the stent and the tissue are extracted. For the evaluation of the method, tests were run using the clinical data from 21 patients. Stent modeling and extraction of the radial forces were successful in 18 cases. Synthetic test cases were generated, in addition, for assessing the sensitivity to the measurement errors. In a sensitivity analysis, the geometric error of the stent reconstruction was below 0.3 mm, which is below the image resolution. The distribution of the radial forces was qualitatively and quantitatively reasonable. An uncertainty remains in the quantitative evaluation of the radial forces due to the uncertainty in defining a radial direction on the <span class="hlt">deformed</span> stent. With our approach, the <span class="hlt">mechanical</span> situation of TAVI stents after the implantation can be studied in vivo, which may help to understand the <span class="hlt">mechanisms</span> that lead to the complications and improve stent design. PMID:24626769</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011SPIE.8321E..3EL','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011SPIE.8321E..3EL"><span id="translatedtitle">A system for the measurement of thermal <span class="hlt">deformation</span> of <span class="hlt">mechanical</span> parts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luo, Zai; Liu, Ningxia; Luo, Quan; Jin, Langbin</p> <p>2011-12-01</p> <p>A high-accuracy system to measure the thermal <span class="hlt">deformation</span> of <span class="hlt">mechanical</span> parts is proposed, which combines two-frequency laser interferometer, constant temperature cabinet and position finding part. The whole system include four parts. The two-frequency laser interferometer is used for measuring the displacement, and the constant temperature cabinet controls the temperature of the <span class="hlt">mechanical</span> parts. Each part may bring in some uncertainty. To different workpieces, the ultimate principle is actually very similar although measurement methods may be a little difference. Various errors related to system are analyzed by processing the measured original displacement data using mathematics analysis and methods of error analysis. Error analysis and experimental studies are presented to approve this system which has high measurement accuracy and high accuracy of temperature control. Taking diameter measured about cylindrical work pieces for instance, the accuracy of the system is analyzed. The result of thermal <span class="hlt">deformation</span> in steady temperature field is proved. The results also show that there is a good repeatability with deviation of 0.5μm in the system when the same diametric thermal <span class="hlt">deformation</span> of a Φ 50mm cylindrical piece in the same temperature variation is measured for 5 times.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPS...297..217F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPS...297..217F"><span id="translatedtitle">Chromium vaporization from <span class="hlt">mechanically</span> <span class="hlt">deformed</span> pre-coated interconnects in Solid Oxide Fuel Cells</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falk-Windisch, Hannes; Sattari, Mohammad; Svensson, Jan-Erik; Froitzheim, Jan</p> <p>2015-11-01</p> <p>Cathode poisoning, associated with Cr evaporation from interconnect material, is one of the most important degradation <span class="hlt">mechanisms</span> in Solid Oxide Fuel Cells when Cr2O3-forming steels are used as the interconnect material. Coating these steels with a thin Co layer has proven to decrease Cr vaporization. To reduce production costs, it is suggested that thin metallic PVD coatings be applied to each steel strip before pressing the material into interconnect shape. This process would enable high volume production without the need for an extra post-coating step. However, when the pre-coated material is <span class="hlt">mechanically</span> <span class="hlt">deformed</span>, cracks may form and lower the quality of the coating. In the present study, Chromium volatilization is measured in an air-3% H2O environment at 850 °C for 336 h. Three materials coated with 600 nm Co are investigated and compared to an uncoated material. The effect of <span class="hlt">deformation</span> is investigated on real interconnects. Microscopy observations reveal the presence of cracks in the order of several μm on the <span class="hlt">deformed</span> pre-coated steel. However, upon exposure, the cracks can heal and form a continuous surface oxide rich in Co and Mn. As an effect of the rapid healing, no increase in Cr vaporization is measured for the pre-coated material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/8876774','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/8876774"><span id="translatedtitle">Molecular <span class="hlt">mechanisms</span> of microglial <span class="hlt">activation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zielasek, J; Hartung, H P</p> <p>1996-01-01</p> <p>Microglial cells are brain macrophages which serve specific functions in the defense of the central nervous system (CNS) against microorganisms, the removal of tissue debris in neurodegenerative diseases or during normal development, and in autoimmune inflammatory disorders of the brain. In cultured microglial cells, several soluble inflammatory mediators such as cytokines and bacterial products like lipopolysaccharide (LPS) were demonstrated to induce a wide range of microglial <span class="hlt">activities</span>, e.g. increased phagocytosis, chemotaxis, secretion of cytokines, <span class="hlt">activation</span> of the respiratory burst and induction of nitric oxide synthase. Since heightened microglial <span class="hlt">activation</span> was shown to play a role in the pathogenesis of experimental inflammatory CNS disorders, understanding the molecular <span class="hlt">mechanisms</span> of microglial <span class="hlt">activation</span> may lead to new treatment strategies for neurodegenerative disorders, multiple sclerosis and bacterial or viral infections of the nervous system. PMID:8876774</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.5144C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.5144C&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> of olivine single crystals compressed at 300 MPa and 800-1100°C</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cordier, Patrick; Demouchy, Sylvie; Mussi, Alexandre; Tommasi, Andrea</p> <p>2013-04-01</p> <p>Rheology of mantle rocks at lithospheric temperatures remains poorly constrained, since most experimental studies on creep <span class="hlt">mechanisms</span> of olivine single crystals ((MgFe)2SiO4, Pbnm) and polycrystalline olivine aggregates were performed at high-temperatures (T >> 1200oC). In this study, we have performed <span class="hlt">deformation</span> experiments on oriented single crystals of San Carlos olivine and polycrystalline olivine aggregate at temperatures relevant of the uppermost mantle (ranging from 800o to 1090oC) in tri-axial compression. The experiments were carried out at a confining pressure of 300 MPa in a high-resolution gas-medium <span class="hlt">mechanical</span> testing apparatus at various constant strain rates (from 7 × 10-6 s-1 to 1 × 10-4 s-1). <span class="hlt">Mechanical</span> tests yield differential stresses ranging from 88 to 1076 MPa. All samples were <span class="hlt">deformed</span> at constant displacement rate and for finite strains ranging from 4 to 23 %, to provide insight into possible effects of hardening, softening or stick-and-slip. The single crystals were compressed along several crystallographic directions to test the possibility of <span class="hlt">activating</span> different slip systems (e.g. [100](001), [001](100), [001](010) and [100](010)). We will present the characterization of the dislocation microstructures performed in the TEM.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFM.T13G..01N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFM.T13G..01N"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> in Western Turkey: new GPS observations and models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nocquet, J.; Aktug, B.; Parsons, B.; Cingoz, A.; England, P.; Erkan, Y.; Soyer, N.; Akdeniz, H.; Kilicoglu, A.</p> <p>2007-12-01</p> <p>How the continents <span class="hlt">deform</span> remains a matter of debate. One view postulates that continental <span class="hlt">deforming</span> zones are comprised of a limited numbers of rigid (elastic) microplates. If true, the surface motion can then be described by the relative rotation of blocks, and strain should be localized along the major faults separating the blocks. An alternative view is that the <span class="hlt">deformation</span> at depth is distributed over wide areas, can be modelled by a viscous flow responding to boundary conditions applied on it and gravitational potential energy gradients related to variations in topography, and the surface strain simply reflects this <span class="hlt">deformation</span>. Western Turkey is a region of crustal extension, part of the Nubia/Eurasia plate boundary. Its kinematics is often modelled by the relative motion of a small number of rigid blocks (Nyst & Thatcher, 2005, Reilinger et al., 2006). However, until now, the limited number of GPS velocity vectors available has prevented a detailed examination of which is the more appropriate description. We present a new geodetic velocity field including ~100 sites from the longitude the Central Anatolian plateau to the Aegean coast, derived from a combination of campaigns carried out between 1997 and 2006, and continuous GPS operating since 2003, which we use to test the different models. While the kinematics of the area can be correctly modelled by a block model, a good fit to the velocity field requires blocks with sizes smaller than 100 km and still fails to adequately predict the strain rate observed within blocks . Alternatively, we test an approach where the lithosphere is modelled as a thin viscous sheet, responding to the gravitational potentiel energy contrast between the high plateau of eastern Turkey to the east and the subduction along the Hellenic trench in the southwest. The simplistic model has only one free parameter (the force applied by the subducting oceanic lithosphere on the Aegean ), but provides a good agreement with the observed</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT.......217A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT.......217A"><span id="translatedtitle"><span class="hlt">Active</span> and long-lived permanent forearc <span class="hlt">deformation</span> driven by the subduction seismic cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aron Melo, Felipe Alejandro</p> <p></p> <p>I have used geological, geophysical and engineering methods to explore <span class="hlt">mechanisms</span> of upper plate, brittle <span class="hlt">deformation</span> at <span class="hlt">active</span> forearc regions. My dissertation particularly addresses the permanent <span class="hlt">deformation</span> style experienced by the forearc following great subduction ruptures, such as the 2010 M w8.8 Maule, Chile and 2011 Mw9.0 Tohoku, Japan earthquakes. These events triggered large, shallow seismicity on upper plate normal faults above the rupture reaching Mw7.0. First I present new structural data from the Chilean Coastal Cordillera over the rupture zone of the Maule earthquake. The study area contains the Pichilemu normal fault, which produced the large crustal aftershocks of the megathrust event. Normal faults are the major neotectonic structural elements but reverse faults also exist. Crustal seismicity and GPS surface displacements show that the forearc experiences pulses of rapid coseismic extension, parallel to the heave of the megathrust, and slow interseismic, convergence-parallel shortening. These cycles, over geologic time, build the forearc structural grain, reactivating structures properly-oriented respect to the <span class="hlt">deformation</span> field of each stage of the interplate cycle. Great subduction events may play a fundamental role in constructing the crustal architecture of extensional forearc regions. Static <span class="hlt">mechanical</span> models of coseismic and interseismic upper plate <span class="hlt">deformation</span> are used to explore for distinct features that could result from brittle fracturing over the two stages of the interplate cycle. I show that the semi-elliptical outline of the first-order normal faults along the Coastal Cordillera may define the location of a characteristic, long-lived megathrust segment. Finally, using data from the Global CMT catalog I analyzed the seismic behavior through time of forearc regions that have experienced great subduction ruptures >Mw7.7 worldwide. Between 61% and 83% of the cases where upper plate earthquakes exhibited periods of increased seismicity</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880019847','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880019847"><span id="translatedtitle">Intraplate <span class="hlt">deformation</span>, stress in the lithosphere and the driving <span class="hlt">mechanism</span> for plate motions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hager, Bradford H.</p> <p>1988-01-01</p> <p>During this period work was carried out on three fronts relevant to the understanding of intraplate <span class="hlt">deformation</span>, stress in the lithosphere, and the driving <span class="hlt">mechanisms</span> for plate motions: (1) observational constraints, using GPS geodesy on the <span class="hlt">deformation</span> in the region of the boundry between the Pacific and North American plates in central and southern California; (2) numerical modeling of the effects of temperature dependent lithospheric viscosity on the stress and strain history of extensional regimes; and (3) improvement of estimates of mantle viscosity variation, the long-wave-length density variations in the mantle, and the topography of the core-mantel boundary from modeling of geoid anomalies, nutation, and changes in length of day. These projects are described in more detail, followed by a discussion of meetings attended and a list of abstracts and papers submitted and/or published.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CryRp..60..895S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CryRp..60..895S"><span id="translatedtitle">Study of the <span class="hlt">mechanisms</span> of current-induced suppression of serrated <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shibkov, A. A.; Zolotov, A. E.; Zheltov, M. A.; Denisov, A. A.; Gasanov, M. F.</p> <p>2015-11-01</p> <p>The main results of studying the influence of electric current on the Portevin‒Le Chatelier serrated <span class="hlt">deformation</span> in some commercial aluminum alloys of the Al‒Mg, Al‒Li-Mg, Al‒Zn‒Mg‒Cu, and Al‒Cu systems are reported. It is found that the passage of a low-density (~10-60 A/mm2) dc current leads to the suppression of serrated <span class="hlt">deformation</span> and band formation in all alloys under study, except for the Al‒Cu alloy. Possible <span class="hlt">mechanisms</span> of this phenomenon are discussed, basically in terms of possible influence of current on the processes of precipitation and dynamic strain aging, which are used to explain the Portevin‒Le Chatelier effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/571771','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/571771"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> responsible for the creep resistance of Ti-Al alloys</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Morris, M.A.; Lipe, T.</p> <p>1997-12-31</p> <p>Two {gamma}-based Ti-Al alloys with similar grain sizes and, respectively, lamellar and duplex microstructures have been creep tested at 700 C and constant stresses ranging between 280 and 430 MPa. TEM observations have confirmed that the duplex alloy <span class="hlt">deforms</span> by extensive <span class="hlt">mechanical</span> twinning whose density increases with applied stress and increasing strain. The new twin interfaces subdivide the {gamma} grains throughout the primary stage of creep. At the onset of the minimum creep rate, the twin interfaces in the duplex alloy behave in the same way as the {gamma}/{gamma} or the {alpha}{sub 2}/{gamma} interfaces in the lamellar alloy. However, single dislocations were also present and it appears that in both alloys the <span class="hlt">deformation</span> process is controlled by the accumulation and emission of dislocations from the different interfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/467610','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/467610"><span id="translatedtitle">Hardness and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of highly elastic carbon nitride thin films as studied by nanoindentation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hainsworth, S.V.; Page, T.F.; Sjoestroem, H.; Sundgren, J.E.</p> <p>1997-05-01</p> <p>Carbon nitride (CN{sub x}) thin films (0.18 < x < 0.43), deposited by magnetron sputtering of C in a N{sub 2} discharge, have been observed to be extremely resistant to plastic <span class="hlt">deformation</span> during surface contact (i.e., exhibit a purely elastic response over large strains). Elastic recoveries as high as 90% have been measured by nanoindentation. This paper addresses the problems of estimating Young`s modulus (E) and hardness (H) in such cases and shows how different strategies involving analysis of both loading and unloading curves and measuring the work of indentation each present their own problems. The results of some cyclic contact experiments are also presented and possible <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in the fullerene-like CN{sub x} structures discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMPSo..77..146Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMPSo..77..146Y"><span id="translatedtitle">On the energy conservation during the <span class="hlt">active</span> <span class="hlt">deformation</span> in molecular dynamics simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Fan; Zhong, Zheng</p> <p>2015-04-01</p> <p>In this paper, we examined the energy conservation for the current schemes of applying <span class="hlt">active</span> <span class="hlt">deformation</span> in molecular dynamics (MD) simulations. Specifically, two methods are examined. One is scaling the dimension of the simulation box and the atom positions via an affine transformation, suitable for the periodic system. The other is moving the rigid walls that interact with the atoms in the system, suitable for the non-periodic system. Based on the calculation of the external work and the internal energy change, we present that the atom velocities also need to be updated in the first <span class="hlt">deformation</span> method; otherwise the energy conservation cannot be satisfied. The classic updating scheme is examined, in which any atom crossing the periodic boundary experiences a velocity delta that is equal to the velocity difference between the opposite boundaries. In addition, a new scheme which scales the velocities of all the atoms according to the strain increment is proposed, which is more efficient and realistic than the classic scheme. It is also demonstrated that the Virial stress instead of its interaction part is the correct stress definition that corresponds to Cauchy stress in the continuum <span class="hlt">mechanics</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2720421','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2720421"><span id="translatedtitle"><span class="hlt">Active</span> Fibers: Matching <span class="hlt">Deformable</span> Tract Templates to Diffusion Tensor Images</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Eckstein, Ilya; Shattuck, David W.; Stein, Jason L.; McMahon, Katie L.; de Zubicaray, Greig; Wright, Margaret J.; Thompson, Paul M.; Toga, Arthur W.</p> <p>2009-01-01</p> <p>Reliable quantitative analysis of white matter connectivity in the brain is an open problem in neuroimaging, with common solutions requiring tools for fiber tracking, tractography segmentation and estimation of intersubject correspondence. This paper proposes a novel, template matching approach to the problem. In the proposed method, a <span class="hlt">deformable</span> fiber-bundle model is aligned directly with the subject tensor field, skipping the fiber tracking step. Furthermore, the use of a common template eliminates the need for tractography segmentation and defines intersubject shape correspondence. The method is validated using phantom DTI data and applications are presented, including automatic fiber-bundle reconstruction and tract-based morphometry. PMID:19457360</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21643092','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21643092"><span id="translatedtitle"><span class="hlt">Deformation</span> of partially pumped <span class="hlt">active</span> mirrors for high average-power diode-pumped solid-state lasers.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Albach, Daniel; LeTouzé, Geoffroy; Chanteloup, Jean-Christophe</p> <p>2011-04-25</p> <p>We discuss the <span class="hlt">deformation</span> of a partially pumped <span class="hlt">active</span> mirror amplifier as a free standing disk, as implemented in several laser systems. We rely on the Lucia laser project to experimentally evaluate the analytical and numerical <span class="hlt">deformation</span> models. PMID:21643092</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26252422','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26252422"><span id="translatedtitle">Crumpling <span class="hlt">deformation</span> regimes of monolayer graphene on substrate: a molecular <span class="hlt">mechanics</span> study.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Al-Mulla, Talal; Qin, Zhao; Buehler, Markus J</p> <p>2015-09-01</p> <p>Experiments and simulations demonstrating reversible and repeatable crumpling of graphene warrant a detailed understanding of the underlying <span class="hlt">mechanisms</span> of graphene crumple formation, especially for design of tailored nanostructures. To systematically study the formation of crumples in graphene, we use a simple molecular dynamics model, and perform a series of simulations to characterize the finite number of <span class="hlt">deformation</span> regimes of graphene on substrate after compression. We formulate a quantitative measure of predicting these <span class="hlt">deformations</span> based on observed results of the simulations and distinguish graphene crumpling considered in this study from others. In our study, graphene is placed on a model substrate while controlling and varying the interfacial energy between graphene and substrate and the substrate roughness through a set of particles embedded in the substrate. We find that a critical value of interfacial adhesion energy marks a transition point that separates two <span class="hlt">deformation</span> regimes of graphene on substrate under uniaxial compression. The interface between graphene and substrate plays a major role in the formation of crumples, and we show that the choice of substrate can help in designing desired topologies in graphene. PMID:26252422</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PASP..121..260E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PASP..121..260E"><span id="translatedtitle">A Micro Electrical <span class="hlt">Mechanical</span> Systems (MEMS)-based Cryogenic <span class="hlt">Deformable</span> Mirror</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Enya, K.; Kataza, H.; Bierden, P.</p> <p>2009-03-01</p> <p>We present our first results on the development and evaluation of a cryogenic <span class="hlt">deformable</span> mirror (DM) based on Micro Electro <span class="hlt">Mechanical</span> Systems (MEMS) technology. A MEMS silicon-based DM chip with 32 channels, in which each channel is 300 μm × 300 μm in size, was mounted on a silicon substrate in order to minimize distortion and prevent it from being permanently damaged by thermal stresses introduced by cooling. The silicon substrate was oxidized to obtain electric insulation and had a metal fan-out pattern on the surface. For cryogenic tests, we constructed a measurement system consisting of a Fizeau interferometer, a cryostat cooled by liquid N2, zooming optics, electric drivers. The surface of the mirror at 95 K <span class="hlt">deformed</span> in response to the application of a voltage, and no significant difference was found between the <span class="hlt">deformation</span> at 95 K and that at room temperature. The power dissipation by the cryogenic DM was also measured, and we suggest that this is small enough for it to be used in a space cryogenic telescope. The properties of the DM remained unchanged after five cycles of vacuum pumping, cooling, warming, and venting. We conclude that fabricating cryogenic DMs employing MEMS technology is a promising approach. Therefore, we intend to develop a more sophisticated device for actual use, and to look for potential applications including the Space Infrared Telescope for Cosmology & Astrophysics (SPICA), and other missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013MMTA..tmp..597D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013MMTA..tmp..597D&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in the Near-β Titanium Alloy Ti-55531</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dikovits, Martina; Poletti, Cecilia; Warchomicka, Fernando</p> <p>2013-11-01</p> <p>The hot formability of a near-β titanium alloy is studied near the β transus temperature to determine the <span class="hlt">mechanisms</span> of <span class="hlt">deformation</span>. Compression tests of Ti-5Al-5Mo-5V-3Cr-1Zr are carried out using a Gleeble®1500 device between 1036 K and 1116 K (763 °C and 843 °C) and strain rates between 0.001 and 10 s-1. The achieved flow data are used to calculate the efficiency of power dissipation, the strain rate sensitivity, and instability parameters derived from different models. Constitutive equations are built using the stress values at the strain of 0.4. Light optical microscopy and EBSD measurements are used to correlate the parameters that describe formability with the microstructure. It is found that hot <span class="hlt">deformation</span> is achieved by dynamic recovery in the β phase by subgrain formation. Geometric dynamic recrystallization along the β grain boundaries takes place at large <span class="hlt">deformations</span>, high temperatures, and low strain rates. On the other hand, for high strain rates, continuous dynamic recrystallization by lattice rotation already starts at a local strain of 1. Different phenomenological models are used to predict the flow instabilities, where the flow-softening parameter α i provides the best correlation with microstructure as well as the physical understanding. The instabilities observed in this alloy are strongly related to flow localization by adiabatic heat.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22403070','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22403070"><span id="translatedtitle">Non-geometric fluxes, quasi-Hopf twist <span class="hlt">deformations</span>, and nonassociative quantum <span class="hlt">mechanics</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mylonas, Dionysios Szabo, Richard J.; Schupp, Peter</p> <p>2014-12-15</p> <p>We analyse the symmetries underlying nonassociative <span class="hlt">deformations</span> of geometry in non-geometric R-flux compactifications which arise via T-duality from closed strings with constant geometric fluxes. Starting from the non-abelian Lie algebra of translations and Bopp shifts in phase space, together with a suitable cochain twist, we construct the quasi-Hopf algebra of symmetries that <span class="hlt">deforms</span> the algebra of functions and the exterior differential calculus in the phase space description of nonassociative R-space. In this setting, nonassociativity is characterised by the associator 3-cocycle which controls non-coassociativity of the quasi-Hopf algebra. We use abelian 2-cocycle twists to construct maps between the dynamical nonassociative star product and a family of associative star products parametrized by constant momentum surfaces in phase space. We define a suitable integration on these nonassociative spaces and find that the usual cyclicity of associative noncommutative <span class="hlt">deformations</span> is replaced by weaker notions of 2-cyclicity and 3-cyclicity. Using this star product quantization on phase space together with 3-cyclicity, we formulate a consistent version of nonassociative quantum <span class="hlt">mechanics</span>, in which we calculate the expectation values of area and volume operators, and find coarse-graining of the string background due to the R-flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9334G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.9334G&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mechanisms</span> of submicron inclusion re-equilibration during host mineral <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Griffiths, Thomas; Habler, Gerlinde; Abart, Rainer; Rhede, Dieter; Wirth, Richard</p> <p>2014-05-01</p> <p> data, and no subgrain boundaries. Secondly, garnet lattice rotation of up to 10° around rational garnet crystal axes is observed in connection with some already coarsened inclusions. Strain concentrations are widespread in some trails, but rare in others. A TEM foil transecting a garnet domain with concentrated lattice rotation in association with inclusions reveals well developed polygonal subgrain walls with few free dislocations. Where dislocation density is greatest, almost no <100nm inclusions are observed, whereas these are more abundant in unstrained garnet domains despite the foil being located entirely within the optically visible bleaching zone. Chlorite inclusions and formation of etch pits at dislocations at the garnet-chlorite interface demonstrate the presence of fluid along subgrain boundaries during this second bleaching process. In summary, brittle <span class="hlt">deformation</span> in these garnets led to enhanced transport and inclusion re-equilibration by coarsening, forming inclusion trails. The precise <span class="hlt">mechanism</span> allowing enhanced transport is still to be determined and may have involved fluid supply with or without pipe diffusion along introduced dislocations. Later ductile <span class="hlt">deformation</span> via dislocations, concentrated at already coarsened inclusions and enhanced by fluid availability, further affected the nanoinclusion population. The inclusion trail microstructure records complex small-scale interaction between <span class="hlt">deformation</span> and reaction, shedding light on the <span class="hlt">mechanisms</span> by which re-equilibration and strain localisation can influence each other in <span class="hlt">deforming</span> host-inclusion systems. Bestmann et al. (2008) Journal of Structural Geology 30: 777-790</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9148E..45B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9148E..45B"><span id="translatedtitle">The <span class="hlt">deformable</span> secondary mirror of VLT: final electro-<span class="hlt">mechanical</span> and optical acceptance test results</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Briguglio, Runa; Biasi, Roberto; Xompero, Marco; Riccardi, Armando; Andrighettoni, Mario; Pescoller, Dietrich; Angerer, Gerald; Gallieni, Daniele; Vernet, Elise; Kolb, Johann; Arsenault, Robin; Madec, Pierre-Yves</p> <p>2014-07-01</p> <p>The <span class="hlt">Deformable</span> Secondary Mirror (DSM) for the VLT ended the stand-alone electro-<span class="hlt">mechanical</span> and optical acceptance process, entering the test phase as part of the Adaptive Optics Facility (AOF) at the ESO Headquarter (Garching). The VLT-DSM currently represents the most advanced already-built large-format <span class="hlt">deformable</span> mirror with its 1170 voice-coil actuators and its internal metrology based on co-located capacitive sensors to control the shape of the 1.12m-diameter 2mm-thick convex shell. The present paper reports the final results of the electro-<span class="hlt">mechanical</span> and optical characterization of the DSM executed in a collaborative effort by the DSM manufacturing companies (Microgate s.r.l. and A.D.S. International s.r.l.), INAF-Osservatorio Astrofisico di Arcetri and ESO. The electro-<span class="hlt">mechanical</span> acceptance tests have been performed in the company premises and their main purpose was the dynamical characterization of the internal control loop response and the calibration of the system data that are needed for its optimization. The optical acceptance tests have been performed at ESO (Garching) using the ASSIST optical test facility. The main purpose of the tests are the characterization of the optical shell flattening residuals, the corresponding calibration of flattening commands, the optical calibration of the capacitive sensors and the optical calibration of the mirror influence functions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1045414','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1045414"><span id="translatedtitle">The influence of bi-metal interfaces on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in bulk nanolaminar composites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mara, Nathan Allan; Ledonne, Jon; Wynn, Thomas A; Rollett, Anthony D; Beyerlein, I. J.; Misra, Amit</p> <p>2011-01-04</p> <p>In this presentation, we report on the plastic <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in Ag-Cu and Cu-Nb nanocomposites rolled to large reductions. Starting with an Ag-Cu alloy with eutectic lamellar bilayer thickness of 200 nm, we roll the as-cast rods from 9.5 mm diameter to sheets of final thickness varying from 2.4 mm to 500 {micro}m, corresponding to 75% to 95% nominal reduction in thickness. Cu(111) X-ray pole figures of the rolled nanocomposites indicate a measured texture similar to that of Ag but different from that expected during rolling of pure bulk Cu involving dislocation slip alone. Visco-Plastic Self Consistent (VPSC) polycrystal modeling indicate that both silver and copper <span class="hlt">deformed</span> by slip and twinning and the twin fraction reached over 30%, depending on rolling reduction. Because pure Cu is not expected to twin under these processing conditions, we hypothesize that twinning in Cu is induced by twinning in Ag, aided by the presence of high Ag-Cu interfacial content. Molecular Dynamics (MD) simulations are then carried out on perfect and defective Ag-Cu interfaces and the results support this hypothesis. In the Cu-Nb system, it has been found that at individual layer thicknesses of 40 nm and above, physical vapor deposited foils can be rolled to large strains. However, when the layer thickness decreases to {approx}5nm, shear instability during rolling limits ductility. In this work, we show the effects of cladding 5nm CuINb multilayers with 40 nm CuINb multilayers to limit the onset of geometric instability, thereby facilitating the <span class="hlt">deformation</span> of 5nm Cu/Nb multi layers to large rolling strains. Results will be discussed in terms of the effects of the interface on <span class="hlt">deformation</span> processes at diminishing length scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930016340','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930016340"><span id="translatedtitle">Intraplate <span class="hlt">deformation</span>, stress in the lithosphere and the driving <span class="hlt">mechanism</span> for plate motions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Albee, Arden L.</p> <p>1993-01-01</p> <p>The initial research proposed was to use the predictions of geodynamical models of mantle flow, combined with geodetic observations of intraplate strain and stress, to better constrain mantle convection and the driving <span class="hlt">mechanism</span> for plate motions and <span class="hlt">deformation</span>. It is only now that geodetic observations of intraplate strain are becoming sufficiently well resolved to make them useful for substantial geodynamical inference to be made. A model of flow in the mantle that explains almost 90 percent of the variance in the observed longwavelength nonhydrostatic geoid was developed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.T41D2931L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFM.T41D2931L&link_type=ABSTRACT"><span id="translatedtitle">Controls of Lithospheric <span class="hlt">Mechanical</span> Strength on the <span class="hlt">Deformation</span> Pattern of Tien Shan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Y.; Xiong, X.; Zheng, Y.; Hu, X.; Zhang, Y.</p> <p>2015-12-01</p> <p>The Tien Shan is an outstanding example of intracontinental mountain belt, which was built rapidly and formed far away from plate boundaries. It exhibits 300~500 km in width and extends ~2000 km EW, located in central Asia. The Tien Shan is a key area for solution of the problems relating to intracontinental geodynamics. During last decades, despite a large amount of results based on various geological, geophysical and geodetic data about the Tien Shan, however, <span class="hlt">deformation</span> <span class="hlt">mechanism</span> remains controversial and other several principal problems related to its structure and evolution also have not been completely resolved. As for patterns of continental <span class="hlt">deformation</span>, they are always controlled by both the forces applied to the lithosphere and by lithospheric resistance to the forces. The latter is often measured by the <span class="hlt">mechanical</span> strength of lithosphere. The lateral variation of strength of lithosphere has been recognized to be an important factor controlling the spatial construction and temporal evolution of continent. In this study, we investigate the <span class="hlt">mechanical</span> strength (Te) of lithosphere in the Tien Shan using wavelet coherency between Bouguer anomaly and topography. The patterns of Te variations are closely related to major tectonic boundaries and blocks. <span class="hlt">Mechanical</span> strength exhibits a weak zone (Te~5-20km) beneath the Tien Shan while its surrounding blocks including Tarim Basin, Junggar Basin and Kazakh platform are characterized by a strong lithosphere (Te>40km). The lateral variations in <span class="hlt">mechanical</span> strength and velocity field of horizontal movement with GPS demonstrate that strain localization appears at the margins of Tarim Basin, which is also the strong lithospheric domain. It is suggested that the weak lithosphere allows the crustal stress accumulation and the strong lithosphere helps to stress transfer. There is also a good agreement between <span class="hlt">mechanical</span> strength and shear wave velocity structure in upper mantle. It indicates a strong domain located in the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T13E2661P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T13E2661P"><span id="translatedtitle">Multiple <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> operating at seismogenic depths: Tectonic pseudotachylyte and associated <span class="hlt">deformation</span> from the central Sierra Nevada, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prante, M. R.; Evans, J. P.</p> <p>2012-12-01</p> <p>Description and identification of fault-related <span class="hlt">deformation</span> products that are diagnostic of seismic slip have implications for the energy budget of earthquakes, fault strength, and fault-rock assemblages. We describe tectonic pseduotachylyte, cataclastic rocks, crystal-plastic <span class="hlt">deformation</span>, and hydrothermal alteration form faults exhumed from seismogenic depths in the Volcanic Lakes area, in northern Sequoia and Kings Canyon National Park, CA, USA. Fault rock protoliths include Mesozoic granite and granodiorite plutonic and limited metasedimentary and metavolcanic rocks. These plutonic and metamorphic rocks are cross-cut by the E-W striking, steeply dipping, left-lateral strike-slip Granite Pass (GPF) and Glacier Lakes faults (GLF). Cross-cutting relationships and microstructural data suggest that the GPF is the oldest fault in the area and preserves evidence for coeval brittle and plastic crystal <span class="hlt">deformation</span>, and hydrothermal fluid-flow. Tectonic pseudotachylyte from the area has been dated using the 40Ar/39Ar method at 76.6 ± 0.3 Ma; when placed into a thermochronologic framework for the plutonic host rock it can be inferred that the pseudotachylyte formed at depths between 2.4-6.0 km with ambient temperatures between 110-160°C. Exceptionally well preserved tectonic pseudotachylyte from the GLF and GPF contain evidence for a frictional melt origin including: 1) plagioclase spherulites and microlites, 2) injection vein morphology, 3) amygdules, 4) viscous flow banding and folds, and 5) embayed and corroded clasts. Pseudotachylyte from the GPF and GLF is associated with brittle and plastic <span class="hlt">deformation</span> in the damage zone of the faults. Evidence for plastic <span class="hlt">deformation</span> includes undulose extinction, <span class="hlt">deformation</span> lamellae, subgrain development, and grain boundary bulging in quartz; and limited undulose extinction in feldspar. Additionally, abundant hydrothermal alteration and mineralization has been documented in the GPF and GLF fault zones, including, chlorite</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1019981','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1019981"><span id="translatedtitle"><span class="hlt">Deformation</span> of Diopside Single Crystal at Mantle Pressure, 1, <span class="hlt">Mechanical</span> Data</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Amiguet, E.; Raterron, P; Cordier, P; Couvy, H; Chen, J</p> <p>2009-01-01</p> <p>Steady-state <span class="hlt">deformation</span> experiments were carried out in a <span class="hlt">deformation</span>-DIA (D-DIA) high-pressure apparatus on oriented diopside single crystals, at pressure (P) ranging from 3.8 to 8.8 GPa, temperature (T) from 1100 to 1400 C, and differential stress ({sigma}) between 0.2 and 1.7 GPa. Three compression directions were chosen in order to test the <span class="hlt">activity</span> of diopside dislocation slip systems, i.e., 1/2<1 1 0>{l_brace}1 {bar 1} 0{r_brace} systems <span class="hlt">activated</span> together, both [1 0 0](0 1 0) and [0 1 0](1 0 0) systems together, or [0 0 1] dislocation slip <span class="hlt">activated</span> in (1 0 0), (0 1 0) and {l_brace}1 1 0{r_brace} planes. Constant applied stress and specimen strain rates ({var_epsilon}) were monitored in situ using time-resolved synchrotron X-ray diffraction and radiography, respectively. Transmission electron microscopy (TEM) investigation of the run products revealed that dislocation creep was responsible for sample <span class="hlt">deformation</span>. Comparison of the present high-P data with those obtained at room-P by Raterron and Jaoul (1991) - on similar crystals <span class="hlt">deformed</span> at comparable T-{sigma} conditions - allows quantifying the effect of P on 1/2<1 1 0>{l_brace} 1 {bar 1} 0{r_brace} <span class="hlt">activity</span>. This translates into the <span class="hlt">activation</span> volume V* = 17 {+-} 6 cm{sup 3}/mol in the corresponding creep power law. Our data also show that both 1/2<1 1 0> dislocation slips and [0 0 1] have comparable slip <span class="hlt">activities</span> at mantle P and T, while [1 0 0](0 1 0) and [0 1 0](1 0 0) slip systems remain marginal. These results show that P has a significant effect on high-T dislocation creep in diopside, the higher the pressure the harder the crystal, and that this effect is stronger on 1/2<1 1 0> slip than on [0 0 1] slip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFM.T42E..07W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFM.T42E..07W"><span id="translatedtitle">Dissolution and Replacement Creep:A Significant <span class="hlt">Deformation</span> <span class="hlt">Mechanism</span> in Mid-crustal Rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wintsch, R. P.</p> <p>2001-12-01</p> <p>Zoning patterns and zoning truncations in metamorphic minerals in a granodioritic orthogneiss from the Bronson Hill terrane, New England indicate that strain and S-C fabrics in these rocks were produced by dissolution, precipitation, and replacement processes, even at epidote-amphibolite facies metamorphic conditions. The metamorphic fabric is defined by alternating layers and folia dominated by quartz, feldspars, and biotite + epidote. Zoning patterns in most metamorphic plagioclase, orthoclase, epidote, and sphene are truncated at boundaries normal to the shortening direction, suggesting dissolution. Interfaces of relict igneous orthoclase phenocrysts that face the shortening direction are embayed and replaced by biotite, epidote and myrmekitic intergrowths of plagioclase and quartz. Metamorphic plagioclase grains are also replaced by epidote. We interpret these microstructures to reflect strain-enhanced dissolution. The cores of many grains show asymmetric overgrowths with at least two generations of beards, all oriented on the ends of grains that face the extension direction. We interpret these textures to reflect precipitation of components dissolved by <span class="hlt">deformation</span> enhanced dissolution. While biotite and quartz probably <span class="hlt">deformed</span> by dislocation creep, the overall <span class="hlt">deformation</span> was accommodated by dissolution perpendicular to the shortening direction, and precipitation parallel to it. These chemical processes must have been <span class="hlt">activated</span> at lower stresses than the dislocation creep predicted from extrapolations of data from experiments in dry rocks. Thus wet crust is likely to be weaker than calculated from these experimental studies. Where such processes dominate, stress may not be high enough to reach brittle failure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002JSG....24.1179W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002JSG....24.1179W"><span id="translatedtitle">Dissolution and replacement creep: a significant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in mid-crustal rocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wintsch, R. P.; Yi, Keewook</p> <p>2002-07-01</p> <p>Zoning patterns and zoning truncations in metamorphic minerals in a granodioritic orthogneiss indicate that strain and S- C fabrics in these rocks were produced by dissolution, precipitation, and replacement processes, even at epidote-amphibolite facies metamorphic conditions. The metamorphic fabric is defined by alternating layers and folia dominated by quartz, feldspars, and biotite+epidote. Zoning patterns in most metamorphic plagioclase, orthoclase, epidote, and sphene are truncated at boundaries normal to the shortening direction, suggesting dissolution. Interfaces of relict igneous orthoclase phenocrysts that face the shortening direction are embayed and replaced by biotite, epidote, and myrmekitic intergrowths of plagioclase and quartz. Metamorphic plagioclase grains are also replaced by epidote. We interpret these microstructures to reflect strain-enhanced dissolution. The cores of many grains show asymmetric overgrowths with at least two generations of beards, all oriented on the ends of grains that face the extension direction. We interpret these textures to reflect precipitation of components dissolved by <span class="hlt">deformation</span>-enhanced dissolution. While biotite and quartz probably <span class="hlt">deformed</span> by dislocation creep, the overall <span class="hlt">deformation</span> was accommodated by dissolution perpendicular to the shortening direction, and precipitation parallel to it. These chemical processes must have been <span class="hlt">activated</span> at lower stresses than the dislocation creep predicted from extrapolations of data from experiments in dry rocks. Thus wet crust is likely to be weaker than calculated from these experimental studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.usgs.gov/of/2010/1149/','USGSPUBS'); return false;" href="http://pubs.usgs.gov/of/2010/1149/"><span id="translatedtitle">Preliminary atlas of <span class="hlt">active</span> shallow tectonic <span class="hlt">deformation</span> in the Puget Lowland, Washington</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barnett, Elizabeth A.; Haugerud, Ralph A.; Sherrod, Brian L.; Weaver, Craig S.; Pratt, Thomas L.; Blakely, Richard J.</p> <p>2010-01-01</p> <p>This atlas presents an up-to-date map compilation of the geological and geophysical observations that underpin interpretations of <span class="hlt">active</span>, surface-<span class="hlt">deforming</span> faults in the Puget Lowland, Washington. Shallow lowland faults are mapped where observations of <span class="hlt">deformation</span> from paleoseismic, seismic-reflection, and potential-field investigations converge. Together, results from these studies strengthen the identification and characterization of regional faults and show that as many as a dozen shallow faults have been <span class="hlt">active</span> during the Holocene. The suite of maps presented in our atlas identifies sites that have evidence of <span class="hlt">deformation</span> attributed to these shallow faults. For example, the paleoseismic-investigations map shows where coseismic surface rupture and <span class="hlt">deformation</span> produced geomorphic scarps and <span class="hlt">deformed</span> shorelines. Other maps compile results of seismic-reflection and potential-field studies that demonstrate evidence of <span class="hlt">deformation</span> along suspected fault structures in the subsurface. Summary maps show the fault traces derived from, and draped over, the datasets presented in the preceding maps. Overall, the atlas provides map users with a visual overview of the observations and interpretations that support the existence of <span class="hlt">active</span>, shallow faults beneath the densely populated Puget Lowland.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.9823E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.9823E"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> and age constraints of fault zones bordering the Leithagebirge (SE Vienna Basin, Austria).</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Erkmen, C.; Grasemann, B.; Exner, U.</p> <p>2009-04-01</p> <p>In this study we combine remote sensing, structural field mapping and microstructural investigations in order to quantitatively describe a fault zone, which facilitated the exhumation of the Leithagebirge. The Leithagebirge is a horst/ridge, which is located at the southeastern margin of the Vienna Basin (Eastern Austria). The mountains form a SW-NE elongated topographic ridge of 34 km length and 9 km width, bordered by major faults against the sediments of the Vienna Basin in the W, the Eisenstadt Basin in the S and the Pannonian Basin in the E. The elevation of the ridge ranges between 118 m to 484 m (Sonnenberg), rising abruptly from the surrounding, extremely low-relief areas. The lithologies of the Leithagebirge comprise mainly Palaeozoic gneisses and mica schists (i.e Variscan metamorphic basement), which are overlain by Permo-Triassic sediments of the Lower Austroalpine realm. The rocks have been strongly <span class="hlt">deformed</span> and metamorphosed during the Eoalpine orogeny. The metamorphic rocks of the Leithagebirge are overlain by Badenian to Sarmatian sediments dominated by the fossil-rich (Corallineceae) calcarenites (i.e. Leithakalk). Because the outcrop situation is generally very poor, this work focuses on a quarry (Schraufstaedter) near Wimpassing at the SW margin of the Leithagebirge. In this quarry the metamorphic Permo-Triassic sediments consisting of ductily <span class="hlt">deformed</span> quartzites and marble mylonites are exceptionally well exposed. The white quartzites record a weak stretching lineation and <span class="hlt">deformed</span> by dynamic recrystallization <span class="hlt">mechanism</span> (mainly basal glide and subgrain rotation). Locally a quartzite conglomerate with cm-long oblate <span class="hlt">deformed</span> components can be recognized. The quartzites form N-S striking several 10-100 m long lenses, which are tectonically juxtaposed within fined grained marbles, which record a mylonitic foliation with a roughly NW-SE striking stretching lineation. The whole sequence suffered a strong cataclastic overprint as part of a several 100</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JEMat..43.4146H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JEMat..43.4146H"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> Behavior of Sn-Ag-Cu Solders with Minor Addition of 0.05 wt.% Ni</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hammad, A. E.; El-Taher, A. M.</p> <p>2014-11-01</p> <p>The aim of the present work is to develop a comparative evaluation of the microstructural and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> behavior of Sn-Ag-Cu (SAC) solders with the minor addition of 0.05 wt.% Ni. Test results showed that, by adding 0.05Ni element into SAC solders, generated mainly small rod-shaped (Cu,Ni)6Sn5 intermetallic compounds (IMCs) inside the β-Sn phase. Moreover, increasing the Ag content and adding Ni could result in the change of the shape and size of the IMC precipitate. Hence, a significant improvement is observed in the <span class="hlt">mechanical</span> properties of SAC solders with increasing Ag content and Ni addition. On the other hand, the tensile results of Ni-doped SAC solders showed that both the yield stress and ultimate tensile strengths decrease with increasing temperature and with decreasing strain rate. This behavior was attributed to the competing effects of work hardening and dynamic recovery processes. The Sn-2.0Ag-0.5Cu-0.05Ni solder displayed the highest <span class="hlt">mechanical</span> properties due to the formation of hard (Cu,Ni)6Sn5 IMCs. Based on the obtained stress exponents and <span class="hlt">activation</span> energies, it is suggested that the dominant <span class="hlt">deformation</span> <span class="hlt">mechanism</span> in SAC (205)-, SAC (0505)- and SAC (0505)-0.05Ni solders is pipe diffusion, and lattice self-diffusion in SAC (205)-0.05Ni solder. In view of these results, the Sn-2.0Ag-0.5Cu-0.05Ni alloy is a more reliable solder alloy with improved properties compared with other solder alloys tested in the present work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1190758','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1190758"><span id="translatedtitle">Phase transformation as the single-mode <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of silicon</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wong, Sherman; Haberl, Bianca; Williams, James S.; Bradby, Jodie E.</p> <p>2015-06-25</p> <p>The mixture of the metastable body-centered cubic (bc8) and rhombohedral (r8) phases of silicon that is formed via nanoindentation of diamond cubic (dc) silicon exhibits properties that are of scientifc and technological interest. This letter demonstrates that large regions of this mixed phase can be formed in crystalline Si via nanoindentation without signifcant damage to the surrounding crystal. Cross-sectional transmission electron microscopy is used to show that volumes 6 μm wide and up to 650 nm deep can be generated in this way using a spherical tip of ~21.5 μm diameter. The phase transformed region is characterised using both Raman microspectroscopy and transmission electron microscopy. It is found that uniform loading using large spherical indenters can favor phase transformation as the sole <span class="hlt">deformation</span> <span class="hlt">mechanism</span> as long as the maximum load is below a critical level. We suggest that the sluggish nature of the transformation from the dc-Si phase to the metallic (b-Sn) phase normally results in competing <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> such as slip and cracking but these can be suppressed by controlled loading conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1190758-phase-transformation-single-mode-mechanical-deformation-silicon','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1190758-phase-transformation-single-mode-mechanical-deformation-silicon"><span id="translatedtitle">Phase transformation as the single-mode <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of silicon</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Wong, Sherman; Haberl, Bianca; Williams, James S.; Bradby, Jodie E.</p> <p>2015-06-25</p> <p>The mixture of the metastable body-centered cubic (bc8) and rhombohedral (r8) phases of silicon that is formed via nanoindentation of diamond cubic (dc) silicon exhibits properties that are of scientifc and technological interest. This letter demonstrates that large regions of this mixed phase can be formed in crystalline Si via nanoindentation without signifcant damage to the surrounding crystal. Cross-sectional transmission electron microscopy is used to show that volumes 6 μm wide and up to 650 nm deep can be generated in this way using a spherical tip of ~21.5 μm diameter. The phase transformed region is characterised using both Ramanmore » microspectroscopy and transmission electron microscopy. It is found that uniform loading using large spherical indenters can favor phase transformation as the sole <span class="hlt">deformation</span> <span class="hlt">mechanism</span> as long as the maximum load is below a critical level. We suggest that the sluggish nature of the transformation from the dc-Si phase to the metallic (b-Sn) phase normally results in competing <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> such as slip and cracking but these can be suppressed by controlled loading conditions.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22308755','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22308755"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> during nanoindentation of sodium borosilicate glasses of nuclear interest</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kilymis, D. A.; Delaye, J.-M.</p> <p>2014-07-07</p> <p>In this paper we analyze results of Molecular Dynamics simulations of Vickers nanoindentation, performed for sodium borosilicate glasses of interest in the nuclear industry. Three glasses have been studied in their pristine form, as well as a disordered one that is analogous to the real irradiated glass. We focused in the behavior of the glass during the nanoindentation in order to reveal the <span class="hlt">mechanisms</span> of <span class="hlt">deformation</span> and how they are affected by microstructural characteristics. Results have shown a strong dependence on the SiO{sub 2} content of the glass, which promotes densification due to the open structure of SiO{sub 4} tetrahedra and also due to the strength of Si-O bonds. Densification for the glasses is primarily expressed by the relative decrease of the Si-O-Si and Si-O-B angles, indicating rotation of the structural units and decrease of free volume. The increase of alkali content on the other hand results to higher plasticity of the matrix and increased shear flow. The most important effect on the <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of the disordered glasses is that of the highly depolymerized network that will also induce shear flow and, in combination with the increased free volume, will result in the decreased hardness of these glasses, as has been previously observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4766266','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4766266"><span id="translatedtitle"><span class="hlt">Mechanical</span> dyssynchrony and <span class="hlt">deformation</span> imaging in patients with functional mitral regurgitation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rosa, Isabella; Marini, Claudia; Stella, Stefano; Ancona, Francesco; Spartera, Marco; Margonato, Alberto; Agricola, Eustachio</p> <p>2016-01-01</p> <p>Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic <span class="hlt">mechanisms</span> are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different <span class="hlt">mechanisms</span>: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. <span class="hlt">Deformation</span> imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve <span class="hlt">deformation</span> indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome. PMID:26981211</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3587370','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3587370"><span id="translatedtitle">Influence of grain shape and orientation on the <span class="hlt">mechanical</span> properties of high pressure torsion <span class="hlt">deformed</span> nickel</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Rathmayr, Georg B.; Hohenwarter, Anton; Pippan, Reinhard</p> <p>2013-01-01</p> <p>Severely plastically <span class="hlt">deformed</span> (SPD) materials, for example those produced by high pressure torsion (HPT), are reported to possess outstanding <span class="hlt">mechanical</span> properties. A typical HPT microstructure consists of elongated grains, usually of grain size well below 1 μm, which are aligned parallel to the shear plane and showing typical shear texture components. To answer the question of how these single features of a SPD microstructure affect the <span class="hlt">mechanical</span> properties individually, such as the yield strength, the ultimate tensile strength, the uniform elongation and the reduction in area, uniaxial tensile tests have been conducted. The samples were tested in two different orientations. Within the same testing orientation the average grain aspect ratio was also varied. The variation in grain aspect ratio within a sample was achieved through a slight back rotation of the already <span class="hlt">deformed</span> material and selective radius-dependent specimen extraction. The main results are as follows: the ductility (in terms of the reduction in area) is influenced by the grain aspect ratio. In contrast, the ultimate tensile strength is independent of the grain aspect ratio but shows an explicit dependency on the specimen orientation. PMID:23482440</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApSS..362..441X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApSS..362..441X"><span id="translatedtitle">A molecular simulation study of chemical degradation and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of hydrated Nafion membranes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Jing; Ban, Shuai; Liu, Bei; Zhou, Hongjun</p> <p>2016-01-01</p> <p>A combined modeling approach using kinetic Monte Carlo and molecular dynamics simulations is applied to investigate both chemical and <span class="hlt">mechanical</span> degradation of Nafion membranes on the molecular level. In different hydration conditions, two major degradation reactions are identified to be the main chain unzipping and the side chain scission. The dissolution process of Nafion is evaluated in terms of weight loss, production emission rate and evolution of functional groups. Further, the complicated structural <span class="hlt">deformation</span> is preliminarily investigated by imposing linear strain on degraded Nafion membrane. Different craze patterns are compared before and after chemical degradation, and the <span class="hlt">mechanism</span> of crack propagation is proposed. Finally, prospective applications of our modeling approach are addressed for future studies of membrane degradation phenomena under fuel cell operation conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4622079','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4622079"><span id="translatedtitle">Sintering boron carbide ceramics without grain growth by plastic <span class="hlt">deformation</span> as the dominant densification <span class="hlt">mechanism</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ji, Wei; Rehman, Sahibzada Shakir; Wang, Weimin; Wang, Hao; Wang, Yucheng; Zhang, Jinyong; Zhang, Fan; Fu, Zhengyi</p> <p>2015-01-01</p> <p>A new ceramic sintering approach employing plastic <span class="hlt">deformation</span> as the dominant <span class="hlt">mechanism</span> is proposed, at low temperature close to the onset point of grain growth and under high pressure. Based on this route, fully dense boron carbide without grain growth can be prepared at 1,675–1,700 °C and under pressure of (≥) 80 MPa in 5 minutes. The dense boron carbide shows excellent <span class="hlt">mechanical</span> properties, including Vickers hardness of 37.8 GPa, flexural strength of 445.3 MPa and fracture toughness of 4.7 MPa•m0.5. Such a process should also facilitate the cost-effective preparation of other advanced ceramics for practical applications. PMID:26503706</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007JAP...102j4507C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007JAP...102j4507C&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mechanical</span> stress altered electron gate tunneling current and extraction of conduction band <span class="hlt">deformation</span> potentials for germanium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Choi, Youn Sung; Lim, Ji-Song; Numata, Toshinori; Nishida, Toshikazu; Thompson, Scott E.</p> <p>2007-11-01</p> <p>Strain altered electron gate tunneling current is measured for germanium (Ge) metal-oxide-semiconductor devices with HfO2 gate dielectric. Uniaxial <span class="hlt">mechanical</span> stress is applied using four-point wafer bending along [100] and [110] directions to extract both dilation and shear <span class="hlt">deformation</span> potential constants of Ge. Least-squares fit to the experimental data results in Ξd and Ξu of -4.3±0.3 and 16.5±0.5 eV, respectively, which agree with theoretical calculations. The dominant <span class="hlt">mechanism</span> for the strain altered electron gate tunneling current is a strain-induced change in the conduction band offset between Ge and HfO2. Tensile stress reduces the offset and increases the gate tunneling current for Ge while the opposite occurs for Si.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014PhDT........71Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........71Y"><span id="translatedtitle">Cyclic Plastic <span class="hlt">Deformation</span>, Fatigue, and the Associated Micro-<span class="hlt">Mechanisms</span> in Magnesium: From Single Crystal to Polycrystal</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, Qin</p> <p></p> <p>Magnesium and its alloys have received substantial interests as the government initiatives on energy saving and environment protection demand an increasing use of lightweight materials in structural parts, especially in transportation industries. A good understanding of fatigue behavior in magnesium is critical to ensure the reliability and durability of the magnesium components. Unlike the body centered cubic and face centered cubic metals, fundamental knowledge concerning the cyclic <span class="hlt">deformation</span> and fatigue in hexagonal close packed magnesium is limited. The current research aims at a better understanding of the micro-<span class="hlt">mechanisms</span> associated with the cyclic <span class="hlt">deformation</span> and fatigue of magnesium. Magnesium single crystal was chosen to study the fundamental twinning/detwinning process while extruded polycrystalline pure magnesium was studied for the fatigue damage <span class="hlt">mechanisms</span>. Cyclic <span class="hlt">deformation</span> and the corresponding morphology evolution of {1 0 1¯ 2} twinning-detwinning-retwinning are, for the first time, characterized in magnesium single crystal under fully reserved strain-controlled tension-compression utilizing in situ optical microscopy. As loading cycles are increased, the <span class="hlt">activity</span> of twinning-detwinning-retwinning gradually decreases. Microscopy after fatigue shows that the matrix region having experienced repeated twinning-detwinning cannot be completely detwinned to its original crystal orientation. Fragmented secondary tension twins are found to result from twin-twin interactions. Various twin-twin interaction structures exist in fatigued magnesium single crystal: quilted-looking twin structure, "apparent crossing" twin structure, and double tension twin structure. According to the crystallography of magnesium, twin-twin interactions are classified into Type I for two twin variants sharing the same zone axis and Type II for two twins with different zone axes. For Type I twin-twin interactions, one twin does not transmit across the twin boundary and into the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....2550M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....2550M"><span id="translatedtitle">Three-dimensional morphology of pores and cracks in intact and <span class="hlt">mechanically</span> <span class="hlt">deformed</span> sandstones</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Menendez, B.; David, C.; Wong, T.-F.; Martinez-Nistal, A.</p> <p>2003-04-01</p> <p>We have studied four different sandstones under confocal laser scanning microscopy (CLSM). In order to discriminate the void space from the grains, the samples were impregnated with a fluorescent dyed (Rhodamine B) resin and thin-sections with a thickness larger than usual were prepared and studied with CSLM. Two different kinds of samples have been studied: <span class="hlt">mechanically</span> <span class="hlt">deformed</span> samples of Darley Dale and Berea sandstones and intact samples of Rothbach and Bentheim sandstones. On each sample several three dimensional blocks have been investigated with size 228 by 152 microns and depths ranging from 35 to 100 microns. From each block a series of tens of parallel "virtual sections" has been recorded, separated by 1 or 2 microns in depth. First we show some examples on Darley Dale and Berea sandstone samples <span class="hlt">deformed</span> in triaxial experiments. Rotating animations are built from series of 3D views of reconstructed crack networks taken step by step for different block orientations. When put together these 3D views nicely simulate a rotation of the 3D block. To create and run the animations we used the Confocal Assistant free software on a PC. Spectacular 3D animations representing crack networks in <span class="hlt">mechanically</span> <span class="hlt">deformed</span> samples are obtained this way in a very short time: some examples will be shown on the screen. Secondly we show on a poster some static 3D reconstructions of the pore and/or crack networks obtained using the Slicer Dicer software. For the intact samples we observe that pore (or grain) walls are smoother in Bentheim sandstone whereas in Rothbach sandstone the presence of a significant amount of coating clay minerals results in a visible surface roughness. Some differences in pore size and pore shape were also observed, with a more homogeneous distribution in Bentheim sandstone than in Rothbach sandstone. In both sandstones we observe the classical pore-to-throats junctions. Complex contact geometry between adjacent grains are sometimes observed. In the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMNS51A1740F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011AGUFMNS51A1740F&link_type=ABSTRACT"><span id="translatedtitle">Geophysical analysis of rock glacier internal structure and implications for <span class="hlt">deformation</span> <span class="hlt">mechanics</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Florentine, C. E.; Skidmore, M. L.; Speece, M. A.; Link, C. A.; Locke, W. W.; Carr, C. G.; Shaw, C. A.</p> <p>2011-12-01</p> <p> invoked to explain either a direct connection between individual transverse ridges to sub-surface structures or a specific structural regime. Our passive roof duplex faulting interpretation of GPR data at the LPRG is consistent with findings from previous studies on the internal composition and structure of rock glaciers and thus provides a testable model for improved understanding of rock glacier <span class="hlt">deformation</span> <span class="hlt">mechanics</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24398783','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24398783"><span id="translatedtitle">Reversible cyclic <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of gold nanowires by twinning-detwinning transition evidenced from in situ TEM.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Lee, Subin; Im, Jiseong; Yoo, Youngdong; Bitzek, Erik; Kiener, Daniel; Richter, Gunther; Kim, Bongsoo; Oh, Sang Ho</p> <p>2014-01-01</p> <p><span class="hlt">Mechanical</span> response of metal nanowires has recently attracted a lot of interest due to their ultra-high strengths and unique <span class="hlt">deformation</span> behaviours. Atomistic simulations have predicted that face-centered cubic metal nanowires <span class="hlt">deform</span> in different modes depending on the orientation between wire axis and loading direction. Here we report, by combination of in situ transmission electron microscopy and molecular dynamic simulation, the conditions under which particular <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> take place during the uniaxial loading of [110]-oriented Au nanowires. Furthermore, by performing cyclic uniaxial loading, we show reversible plastic <span class="hlt">deformation</span> by twinning and consecutive detwinning in tension and compression, respectively. Molecular dynamics simulations rationalize the observed behaviours in terms of the orientation-dependent resolved shear stress on the leading and trailing partial dislocations, their potential nucleation sites and energy barriers. This reversible twinning-detwinning process accommodates large strains that can be beneficially utilized in applications requiring high ductility in addition to ultra-high strength. PMID:24398783</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21384869','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21384869"><span id="translatedtitle">Flaw tolerance of nuclear intermediate filament lamina under extreme <span class="hlt">mechanical</span> <span class="hlt">deformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qin, Zhao; Buehler, Markus J</p> <p>2011-04-26</p> <p>The nuclear lamina, composed of intermediate filaments, is a structural protein meshwork at the nuclear membrane that protects genetic material and regulates gene expression. Here we uncover the physical basis of the material design of nuclear lamina that enables it to withstand extreme <span class="hlt">mechanical</span> <span class="hlt">deformation</span> of >100% strain despite the presence of structural defects. Through a simple in silico model we demonstrate that this is due to nanoscale <span class="hlt">mechanisms</span> including protein unfolding, alpha-to-beta transition, and sliding, resulting in a characteristic nonlinear force-extension curve. At the larger microscale this leads to an extreme delocalization of <span class="hlt">mechanical</span> energy dissipation, preventing catastrophic crack propagation. Yet, when catastrophic failure occurs under extreme loading, individual protein filaments are sacrificed rather than the entire meshwork. This <span class="hlt">mechanism</span> is theoretically explained by a characteristic change of the tangent stress-strain hardening exponent under increasing strain. Our results elucidate the large extensibility of the nuclear lamina within muscle or skin tissue and potentially many other protein materials that are exposed to extreme <span class="hlt">mechanical</span> conditions, and provide a new paradigm toward the de novo design of protein materials by engineering the nonlinear stress-strain response to facilitate flaw-tolerant behavior. PMID:21384869</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT........58B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT........58B"><span id="translatedtitle">Investigation of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of core-shell rubber-modified epoxy at cryogenic temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Hayley Rebecca</p> <p></p> <p>The industrial demand for high strength-to-weight ratio materials is increasing due to the need for high performance components. Epoxy polymers, although often used in fiber-reinforced polymeric composites, have an inherent low toughness that further decreases with decreasing temperatures. Second-phase additives have been effective in increasing the toughness of epoxies at room temperature; however, the <span class="hlt">mechanisms</span> at low temperatures are still not understood. In this study, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a DGEBA epoxy modified with MX960 core-shell rubber (CSR) particles were investigated under quasi-static tensile and impact loads at room temperature (RT) and liquid nitrogen (LN 2) temperature. Overall, the CSR had little effect on the tensile properties at RT and LN2 temperature. The impact strength decreased from neat to 3 wt% but increased from neat to 5 wt% at RT and LN2 temperature, with a higher impact strength at RT at all CSR loadings. The CSR particles debonded in front of the crack tip, inducing voids into the matrix. It was found that an increase in shear <span class="hlt">deformation</span> and void growth likely accounted for the higher impact strength at 5 wt% CSR loading at RT while the thermal stress fields due to the coefficient of thermal expansion mismatch between rubber and epoxy and an increase in secondary cracking is likely responsible for the higher impact strength at 5 wt% tested at LN2 temperature. While a large toughening effect was not seen in this study, the <span class="hlt">mechanisms</span> analyzed herein will likely be of use for further material investigations at cryogenic temperatures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1510426V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1510426V"><span id="translatedtitle"><span class="hlt">Deformation</span> and failure of single- and multi-phase silicate liquids: seismic precursors and <span class="hlt">mechanical</span> work</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vasseur, Jeremie; Lavallée, Yan; Hess, Kai-Uwe; Wassermann, Joachim; Dingwell, Donald B.</p> <p>2013-04-01</p> <p>Along with many others, volcanic unrest is regarded as a catastrophic material failure phenomenon and is often preceded by diverse precursory signals. Although a volcanic system intrinsically behave in a non-linear and stochastic way, these precursors display systematic evolutionary trends to upcoming eruptions. Seismic signals in particular are in general dramatically increasing prior to an eruption and have been extensively reported to show accelerating rates through time, as well as in the laboratory before failure of rock samples. At the lab-scale, acoustic emissions (AE) are high frequency transient stress waves used to track fracture initiation and propagation inside a rock sample. Synthesized glass samples featuring a range of porosities (0 - 30%) and natural rock samples from volcán de Colima, Mexico, have been failed under high temperature uniaxial compression experiments at constant stresses and strain rates. Using the monitored AEs and the generated <span class="hlt">mechanical</span> work during <span class="hlt">deformation</span>, we investigated the evolutionary trends of energy patterns associated to different degrees of heterogeneity. We observed that the failure of dense, poorly porous glasses is achieved by exceeding elevated strength and thus requires a significant accumulation of strain, meaning only pervasive small-scale cracking is occurring. More porous glasses as well as volcanic samples need much lower applied stress and <span class="hlt">deformation</span> to fail, as fractures are nucleating, propagating and coalescing into localized large-scale cracks, taking the advantage of the existence of numerous defects (voids for glasses, voids and crystals for volcanic rocks). These observations demonstrate that the <span class="hlt">mechanical</span> work generated through cracking is efficiently distributed inside denser and more homogeneous samples, as underlined by the overall lower AE energy released during experiments. In contrast, the quicker and larger AE energy released during the loading of heterogeneous samples shows that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFM.G42A..01D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFM.G42A..01D"><span id="translatedtitle">Evolution of <span class="hlt">Deformation</span> Studies on <span class="hlt">Active</span> Hawaiian Volcanoes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Decker, R.; Okamura, A.</p> <p>2004-12-01</p> <p>Summarizing 1600 years of observations and interpretations into a brief presentation forces some difficult choices on highlighting the following techniques that are presented chronologically: Visual Observations, 400 AD to present: Missionary William Ellis' Hawaiian Guides told him that Kilauea "had been burning from time immemorial, or, to use their own words, `mai ka po mai', from chaos till now...that in earlier ages it used to boil up, overflow its banks, and inundate the adjacent country...and on occasions they supposed Pele went by a road under ground from her house in the crater to the shore". Observations of the nearly-continuous lava lake in Kilauea Caldera from 1823 until 1924 established that its surface level fluctuated from about 700 to 1100 m above sea level in 10 up-and-down episodes. Tilt Measurements, 1914 to present: Horizontal-seismometer drift and water-tube tiltmeters show that the range of long-term, ground-surface tilt radial to Halemaumau Crater exceeds 500 microradians. Triangulation and Leveling, 1920: R. M. Wilson measured <span class="hlt">deformation</span> changes related to major Kilauea summit subsidence in 1924. The caldera area around Halemaumau subsided concentrically as much as 4 m relative to the Volcano House benchmark, and triangulation points moved toward Halemaumau by as much as 1.6 m in the caldera area. K. Mogi in 1958 modeled Kilauea leveling data and inferred 3-4 km-deep magma reservoirs. Gravity Measurements, 1959 to present: Changes were first measured during Kilauea summit subsidence related to the lower-east-rift Kapoho eruption. Surveys made before and after the 1975 M7.2 Kalapana Earthquake show that gravity changes are not a simple proxy for elevation changes. Electronic Distance Measurements (EDM), 1964 to present: D. A. Swanson, W. A. Duffield, and R. S. Fiske use EDM for trilateration proving movement of the south flank of Kilauea toward the sea. EDM show displacements as large as 8.7 m of Kilauea's south flank toward the sea related</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012ApCM...19..513B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012ApCM...19..513B"><span id="translatedtitle">Analyses of the <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> of Non-Crimp Fabric Composite Reinforcements during Preforming</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bel, Sylvain; Boisse, Philippe; Dumont, François</p> <p>2012-06-01</p> <p>Two experimental devices are used for the analysis of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of biaxial non-crimp fabric composite reinforcements during preforming. The bias extension test, commonly use for the shear behaviour characterisation of woven fabrics, allows to highlight the sliding between the two plies of the reinforcement. This sliding is localized in areas of high gradient of shearing. This questions the use of bias extension test in determining the shear stiffness of the studied reinforcement. Then a hemispherical stamping experiment, representative of a preforming process, allows to quantify this sliding. The slippage is defined as the distance, projected onto the middle surface, of two points initially opposed on both sides of the reinforcement. For both experiments, the characteristic behavior of the non-crimp fabric reinforcement is highlighted by comparison with a woven textile reinforcement. This woven fabric presents only a very little sliding between warp and weft yarns during preforming. This aspect of the <span class="hlt">deformation</span> kinematics of the non-crimp fabric reinforcement must be considered when simulating the preforming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6851214','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6851214"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in granodiorite at effective pressures to 100 MPa and temperatures to partial melting</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Friedman, M.; Handin, J.; Bauer, S.J.</p> <p>1981-01-01</p> <p><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in room-dry and water-saturated specimens of Charcoal Granodiorite, shortened at 10/sup -4/s/sup -1/, at effective pressures (Pe) to 100 MPa and temperatures to partial melting (less than or equal to 1050/sup 0/C) are documented with a view toward providing criteria to recognize and characterize the <span class="hlt">deformation</span> for geological and engienering applications. Above 800/sup 0/C strength decreases dramatically at effective pressures greater than or equal to 50 MPa and water-weakening reduces strength an additional 30 to 40% at Pe = 100 MPa. Strains at failure are only 0.1 to 2.2% with macroscopic ductility (within this range) increasing as the effective pressures are increased and in wet versus dry tests. Shattering (multiple faulting) gives way to faulting along a single zone to failure without macroscopic faulting as ductility increases. Microscopically, cataclasis (extension microfracturing and thermal cracking with rigid-body motions) predominates at all conditions. Dislocation gliding contributes little to the strain. Precursive extension microfractures coalesce to produce the throughgoing faults with gouge zones exhibiting possible Riedel shears. Incipient melting, particularly in wet tests, produces a distinctive texture along feldspar grain boundaries that suggests a grain-boundary-softening effect contributes to the weakening. In addition, it is demonstrated that the presence of water does not lead to more microfractures, but to a reduction in the stresses required to initiate and propagate them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JTST...25..982N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JTST...25..982N"><span id="translatedtitle">On the Bonding <span class="hlt">Mechanism</span> in Cold Spray of <span class="hlt">Deformable</span> hex-BN-Ni Clusters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neshastehriz, M.; Smid, I.; Segall, A. E.; Eden, T. J.</p> <p>2016-06-01</p> <p>Bond strength and the lubrication potential of coatings made of 7 µm Hexagonal Boron Nitride particles encapsulated with nickel (hBN-Ni), and deposited onto aluminum 6061 substrates via cold spray were examined; for all tests, N2 was used as the carrier gas at a temperature of 480 °C and pressure of 2.4 MPa. Results showed significant improvement in both wear resistance and reduced surface friction. Coated samples also demonstrated unexpected high bond strength, which was much greater than pure nickel cold sprayed onto aluminum. However, while the results were truly promising, the primary reason for the observed high bond strength could not be explained using existing cold spray theories which were primarily developed for pure metal particles. Based on the present findings compared to cold-sprayed layers of composite nickel-nickel (nickel particles encapsulated with nickel), a <span class="hlt">mechanism</span> for bonding of hBN-Ni particles to aluminum based on the level of plastic <span class="hlt">deformation</span> and hardenability is proposed. Indeed, the high bond strength between the coating and substrate is related to the relatively high initial ductility of the nickel encapsulation, compliance of the hBN, as well as the ensuing significant plastic <span class="hlt">deformation</span> of the composite particles during cold spray deposition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MMTA...46.2431J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MMTA...46.2431J"><span id="translatedtitle">Insights from the Lattice-Strain Evolution on <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Metallic-Glass-Matrix Composites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jia, H. L.; Zheng, L. L.; Li, W. D.; Li, N.; Qiao, J. W.; Wang, G. Y.; Ren, Y.; Liaw, P. K.; Gao, Yanfei</p> <p>2015-06-01</p> <p>In situ high-energy synchrotron X-ray diffraction experiments and micromechanics-based finite element simulations have been conducted to examine the lattice-strain evolution in metallic-glass-matrix composites (MGMCs) with dendritic crystalline phases dispersed in the metallic-glass matrix. Significant plastic <span class="hlt">deformation</span> can be observed prior to failure from the macroscopic stress-strain curves in these MGMCs. The entire lattice-strain evolution curves can be divided into elastic-elastic (denoting <span class="hlt">deformation</span> behavior of matrix and inclusion, respectively), elastic-plastic, and plastic-plastic stages. Characteristics of these three stages are governed by the constitutive laws of the two phases (modeled by free-volume theory and crystal plasticity) and geometric information (crystalline phase morphology and distribution). The load-partitioning <span class="hlt">mechanisms</span> have been revealed among various crystalline orientations and between the two phases, as determined by slip strain fields in crystalline phase and by strain localizations in matrix. Implications on ductility enhancement of MGMCs are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2893916','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2893916"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> Behavior of Nonpolar GaN Thick Films by Berkovich Nanoindentation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2009-01-01</p> <p>In this study, the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of nonpolar GaN thick films grown on m-sapphire by hydride vapor phase epitaxy (HVPE) are investigated using nanoindentation with a Berkovich indenter, cathodoluminescence (CL), and Raman microscopy. Results show that nonpolar GaN is more susceptible to plastic <span class="hlt">deformation</span> and has lower hardness thanc-plane GaN. After indentation, lateral cracks emerge on the nonpolar GaN surface and preferentially propagate parallel to the orientation due to anisotropic defect-related stresses. Moreover, the quenching of CL luminescence can be observed to extend exclusively out from the center of the indentations along the orientation, a trend which is consistent with the evolution of cracks. The recrystallization process happens in the indented regions for the load of 500 mN. Raman area mapping indicates that the distribution of strain field coincides well with the profile of defect-expanded dark regions, while the enhanced compressive stress mainly concentrates in the facets of the indentation. PMID:20596453</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JTST..tmp...47N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JTST..tmp...47N"><span id="translatedtitle">On the Bonding <span class="hlt">Mechanism</span> in Cold Spray of <span class="hlt">Deformable</span> hex-BN-Ni Clusters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Neshastehriz, M.; Smid, I.; Segall, A. E.; Eden, T. J.</p> <p>2016-05-01</p> <p>Bond strength and the lubrication potential of coatings made of 7 µm Hexagonal Boron Nitride particles encapsulated with nickel (hBN-Ni), and deposited onto aluminum 6061 substrates via cold spray were examined; for all tests, N2 was used as the carrier gas at a temperature of 480 °C and pressure of 2.4 MPa. Results showed significant improvement in both wear resistance and reduced surface friction. Coated samples also demonstrated unexpected high bond strength, which was much greater than pure nickel cold sprayed onto aluminum. However, while the results were truly promising, the primary reason for the observed high bond strength could not be explained using existing cold spray theories which were primarily developed for pure metal particles. Based on the present findings compared to cold-sprayed layers of composite nickel-nickel (nickel particles encapsulated with nickel), a <span class="hlt">mechanism</span> for bonding of hBN-Ni particles to aluminum based on the level of plastic <span class="hlt">deformation</span> and hardenability is proposed. Indeed, the high bond strength between the coating and substrate is related to the relatively high initial ductility of the nickel encapsulation, compliance of the hBN, as well as the ensuing significant plastic <span class="hlt">deformation</span> of the composite particles during cold spray deposition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011PhDT.......299M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011PhDT.......299M"><span id="translatedtitle">A diffraction based study of the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in anomalously ductile B2 intermetallics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mulay, Rupalee Prashant</p> <p></p> <p>For many decades, the brittle nature of most intermetallic compounds (e.g. NiAl) has been the limiting factor in their practical application. Many B2 (CsCl prototypical structure) intermetallics are known to exhibit slip on the <001>{110} slip mode, which provides only 3 independent slip systems and, hence, is unable to satisfy the von Mises (a.k.a. Taylor) criterion for polycrystalline ductility. As a result, inherent polycrystalline ductility is unexpected. Recent discovery of a number of ductile B2 intermetallics has raised questions about possible violation of the von Mises criterion by these alloys. These ductile intermetallic compounds are MR (metal (M) combined with a rare earth metal or group IV refractory metal (R)) alloys and are stoichiometric, ordered compounds. Single crystal slip trace analyses have only identified the presence of <100>{011} or <100>{010} slip systems. More than 100 other B2 MR compounds are known to exist and many of them have already been shown to be ductile (e.g., CuY, AgY, CuDy, CoZr, CoTi, etc.). Furthermore, these alloys exhibit a large Bauschinger effect. The present work uses several diffraction based techniques including electron back scattered diffraction (EBSD), X-ray diffraction (XRD) and in-situ neutron diffraction; in conjunction with scanning electron microscopy (SEM), transmission electron microscopy (TEM), <span class="hlt">mechanical</span> testing, and crystal plasticity modeling, to elucidate the reason for ductility in select B2 alloys, explore the spread of this ductility over the B2 family, and understand the Bauschinger effect in these alloys. Several possible explanations (e.g., slip of <111> dislocations, strong texture, phase transformations and twinning) for the anomalous ductility were explored. An X-ray diffraction based analysis ruled out texture, phase purity and departure from order as explanations for the anomalous ductility in MR alloys. In-situ neutron diffraction and post <span class="hlt">deformation</span> SEM, EBSD, and TEM were unable to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFM.U22A..06H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFM.U22A..06H"><span id="translatedtitle">Sumatra-Andaman Megathrust Earthquake Slip: Insights From <span class="hlt">Mechanical</span> Modeling of ICESat Surface <span class="hlt">Deformation</span> Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harding, D. J.; Miuller, J. R.</p> <p>2005-12-01</p> <p> boundary condition on the Sumatra-Andaman subduction interface fault. The direction of slip on the fault surface is derived from the slip directions computed by Tsai et al. (in review) for centroid moment tensor focal <span class="hlt">mechanisms</span> spatially distributed along the rupture. The slip model will be refined to better correspond to the observed surface <span class="hlt">deformation</span> as additional results from the ICESat profiles become available.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014APS..MAR.P1153F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..MAR.P1153F"><span id="translatedtitle">Characterization of actin filament <span class="hlt">deformation</span> in response to <span class="hlt">actively</span> driven microspheres propagated through entangled actin networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Falzone, Tobias; Blair, Savanna; Robertson-Anderson, Rae</p> <p>2014-03-01</p> <p>The semi-flexible biopolymer actin is a ubiquitous component of nearly all biological organisms, playing an important role in many biological processes such as cell structure and motility, cancer invasion and metastasis, muscle contraction, and cell signaling. Concentrated actin networks possess unique viscoelastic properties that have been the subject of much theoretical and experimental work. However, much is still unknown regarding the correlation of the applied stress on the network to the induced filament strain at the molecular level. Here, we use dual optical traps alongside fluorescence microscopy to carry out <span class="hlt">active</span> microrheology measurements that link <span class="hlt">mechanical</span> stress to structural response at the micron scale. Specifically, we <span class="hlt">actively</span> drive microspheres through entangled actin networks while simultaneously measuring the force the surrounding filaments exert on the sphere and visualizing the <span class="hlt">deformation</span> and subsequent relaxation of fluorescent labeled filaments within the network. These measurements, which provide much needed insight into the link between stress and strain in actin networks, are critical for clarifying our theoretical understanding of the complex viscoelastic behavior exhibited in actin networks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APS..MARX21006Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APS..MARX21006Z"><span id="translatedtitle"><span class="hlt">Deformation</span> twinning <span class="hlt">activated</span> α --> ω transformation in titanium under shock compression</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zong, Hongxiang; Lookman, Turab</p> <p></p> <p>Materials dynamics, especially the behavior of solids under extreme compression, is a topic of broad scientific and technological interest. However, less is known of the role of grain boundary structures on the shock response of hexagonal-close-packed metals. We use molecular dynamics simulations to study <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in shock compressed Ti bicrystals containing three types of grain boundary (GB) microstructures, i.e., coherent twin boundaries (CTBs), symmetric incoherent twin boundaries (ITB) and {1-210}asymmetric tilt grain boundaries. Our results show that both dislocation <span class="hlt">activity</span> and the α -> ω phase transformation in Ti are sensitive to the GB characteristics. In particular, we find that the elastic shock wave can readily trigger the α -> ω transformation at CTBs but not at the other two GBs, and the <span class="hlt">activation</span> of the α -> ω transformation at CTBs leads to considerable wave attenuation (i.e., the elastic precursor decay). Combined with first principle calculations, we find that CTBs can facilitate the overcoming of the energy barrier for the α -> ω transformation. Our findings have potential implications for interface engineering and materials design under extreme conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AIPC.1687b0002B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AIPC.1687b0002B&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span>, defects, heat treatment, and thermal conductivity in large grain niobium</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bieler, Thomas R.; Kang, Di; Baars, Derek C.; Chandrasekaran, Saravan; Mapar, Aboozar; Ciovati, Gianluigi; Wright, Neil T.; Pourboghrat, Farhang; Murphy, James E.; Compton, Chris C.; Myneni, Ganapati Rao</p> <p>2015-12-01</p> <p>The physical and <span class="hlt">mechanical</span> metallurgy underlying fabrication of large grain cavities for superconducting radio frequency accelerators is summarized, based on research of 1) grain orientations in ingots, 2) a metallurgical assessment of processing a large grain single cell cavity and a tube, 3) assessment of slip behavior of single crystal tensile samples extracted from a high purity ingot slice before and after annealing at 800 °C / 2 h, 4) development of crystal plasticity models based upon the single crystal experiments, and 5) assessment of how thermal conductivity is affected by strain, heat treatment, and exposure to hydrogen. Because of the large grains, the plastic anisotropy of <span class="hlt">deformation</span> is exaggerated, and heterogeneous strains and localized defects are present to a much greater degree than expected in polycrystalline material, making it highly desirable to computationally anticipate potential forming problems before manufacturing cavities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7007692','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/biblio/7007692"><span id="translatedtitle">Metastable alloy materials produced by solid state reaction of compacted, <span class="hlt">mechanically</span> <span class="hlt">deformed</span> mixtures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Atzmon, M.; Johnson, W.L.; Verhoeven, J.D.</p> <p>1987-02-03</p> <p>Bulk metastable, amorphous or fine crystalline alloy materials are produced by reacting cold-worked, <span class="hlt">mechanically</span> <span class="hlt">deformed</span> filamentary precursors such as metal powder mixtures or intercalated metal foils. Cold-working consolidates the metals, increases the interfacial area, lowers the free energy for reaction, and reduces at least one characteristic dimension of the metals. For example, the grains of powder or the sheets of foil are clad in a container to form a disc. The disc is cold-rolled between the nip of rollers to form a flattened disc. The grains are further elongated by further rolling to form a very thin sheet of a lamellar filamentary structure containing filaments having a thickness of less than 0.01 microns. Thus, diffusion distance and time for reaction are substantially reduced when the flattened foil is thermally treated in oven to form a composite sheet containing metastable material dispersed in unreacted polycrystalline material. 4 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22492683','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22492683"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span>, defects, heat treatment, and thermal conductivity in large grain niobium</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bieler, Thomas R. Kang, Di Baars, Derek C.; Chandrasekaran, Saravan; Mapar, Aboozar Wright, Neil T.; Ciovati, Gianluigi Myneni, Ganapati Rao; Pourboghrat, Farhang; Murphy, James E.; Compton, Chris C.</p> <p>2015-12-04</p> <p>The physical and <span class="hlt">mechanical</span> metallurgy underlying fabrication of large grain cavities for superconducting radio frequency accelerators is summarized, based on research of 1) grain orientations in ingots, 2) a metallurgical assessment of processing a large grain single cell cavity and a tube, 3) assessment of slip behavior of single crystal tensile samples extracted from a high purity ingot slice before and after annealing at 800 °C / 2 h, 4) development of crystal plasticity models based upon the single crystal experiments, and 5) assessment of how thermal conductivity is affected by strain, heat treatment, and exposure to hydrogen. Because of the large grains, the plastic anisotropy of <span class="hlt">deformation</span> is exaggerated, and heterogeneous strains and localized defects are present to a much greater degree than expected in polycrystalline material, making it highly desirable to computationally anticipate potential forming problems before manufacturing cavities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006EPJE...20...29S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006EPJE...20...29S"><span id="translatedtitle">Imbibition, desiccation and <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of zein pills in relation to their porosity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sabino, M. A.; Pauchard, L.; Allain, C.; Colonna, P.; Lourdin, D.</p> <p>2006-05-01</p> <p>This paper deals with the interaction between zein (the main protein component of corn grain) and water. It induces macroscopic properties changes and may allow for the understanding of the basis of zein endosperm structure: vitreous endosperm is compact and floury endosperm is porous, giving the endosperm its hard and soft textures, respectively. In that aim porous pills made by compaction of zein powder submitted to different hydration/dehydration processes have been prepared and studied. In particular, imbibition measurements of a pure-water drop deposited onto a zein pill were performed. Also, desiccation of a zein pill previously imbibed induces strong <span class="hlt">mechanical</span> stresses leading to crack formation and/or large <span class="hlt">deformations</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/290933','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/290933"><span id="translatedtitle">A <span class="hlt">mechanics</span> model for the <span class="hlt">deformation</span> of swirl-mat composites</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Elahi, M.; Weitsman, Y.J.</p> <p>1998-11-01</p> <p>Swirl-mat polymeric composites are considered as representative materials for application in the automotive industry. This article summarizes a three-year long effort to characterize, model, and predict the <span class="hlt">deformation</span> of these composites under stress, temperature, cyclic loadings, and the ingress of fluids. The effort involved several hundred characterization tests of various kinds and the formulation of a constitutive model based upon fundamental principles of irreversible thermodynamics and continuum <span class="hlt">mechanics</span>. The above-mentioned experiments and model development were performed interactively. Subsequently, the model was employed in a predictive manner to anticipate experimental data collected under complex load and temperature histories, as well as to predict long-term behavior from short-term data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19920001736','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19920001736"><span id="translatedtitle">Wrinkle ridge-upland scarp transitions: Implications for the <span class="hlt">mechanical</span> properties of the <span class="hlt">deformed</span> materials</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Watters, Thomas R.; Tuttle, Michael J.; Simpson, Debra</p> <p>1991-01-01</p> <p>Wrinkle ridge-upland scarp transitions are structures that occur at the contact between smooth plains material and highlands or uplands materials on the Moon and Mars. In the smooth plains material the structures have a morphology typical of wrinkle ridges, interpreted to be the result of a combination of folding and thrust faulting. Where the structures extend into the uplands, a distinct change in the morphology occurs. The generally asymmetric cross sectional geometry characteristics of wrinkle ridges becomes that of a one-sided, often lobate scarp. The scarp is indistinguishable from other highland/upland scarps, interpreted to be the result of reverse or thrust faulting. Although these structures are rare, they provide important insight into the <span class="hlt">mechanical</span> properties of <span class="hlt">deformed</span> materials. These insights are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981Tectp..72..323S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981Tectp..72..323S"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> and strain history of a minor fold from the Appalachian Valley and Ridge Province</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spang, J. H.; Groshong, R. H.</p> <p>1981-02-01</p> <p>We have re-examined a minor fold in the Silurian McKenzie limestone, collected from the Cacapon Mountain anticline where the anticline crosses the Potomoc River. The fold was originally studied by James Conel (1962). We have determined the strain and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in both the hinge and the limbs of one layer. The layer is towards the inner arc of a multilayer containing one other bed of comparable thickness and numerous thinner beds, all separated by thin shale beds and enclosed in shale. Intragranular <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> related to folding include faults and replacement veins. The faults represent a complex interrelationship between shear displacement, pressure solution, and extension veins containing fibrous calcite. The faults are curved and have the effect of moving material into the inner arc of the hinge zone. The replacement veins occur normal to bedding on the outer arc of the hinge. Pressure solution zones normal to bedding are absent and so is cleavage. Intragranular strain is measured on twinned calcite using the least-squares strain gage technique. Based on all the data, the maximum compressive strain, ɛ 1, is everywhere subparallel to layering and approximately perpendicular to the fold axis. The maximum extension strain is everywhere subparallel to the fold axis. The largest ɛ 1 values (-12.7 and -11.0%) occur in the inner arc of the hinge; the smallest ɛ 1 (-2.1%) is in the outer arc of the hinge. The limbs have intermediate values of ɛ 1. Intragranular layer-parallel shear strain on the limbs is small and indicates a relative motion of material away from the hinge in the inner arc with respect to the outer arc.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016FrP.....4....2N&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016FrP.....4....2N&link_type=ABSTRACT"><span id="translatedtitle">How stress and temperature conditions affect rock-fluid chemistry and <span class="hlt">mechanical</span> <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nermoen, Anders; Korsnes, Reidar; Aursjø, Olav; Madland, Merete; Kjørslevik, Trygve Alexander; Østensen, Geir</p> <p>2016-02-01</p> <p>We report the results from a series of chalk flow-through-compaction experiments performed at three effective stresses (0.5 MPa, 3.5 MPa and 12.3 MPa) and two temperatures (92° and and 130°). The results show that both stress and temperature are important to both chemical alteration and <span class="hlt">mechanical</span> <span class="hlt">deformation</span>. The experiments were conducted on cores drilled from the same block of outcrop chalks from the Obourg quarry within the Saint Vast formation (Mons, Belgium). The pore pressure was kept at 0.7 MPa for all experiments with a continuous flow of 0.219 M MgCl2 brine at a constant flow rate; 1 original pore volume (PV) per day. The experiments have been performed in tri-axial cells with independent control of the external stress (hydraulic pressure in the confining oil), pore pressure, temperature, and the injected flow rate. Each experiment consists of two phases; a loading phase where stress-strain dependencies are investigated (approx. 2 days), and a creep phase that lasts for more than 150-160 days. During creep, the axial <span class="hlt">deformation</span> was logged, and the effluent samples were collected for ion chromatography analyses. Any difference between the injected and produced water chemistry gives insight into the rock-fluid interactions that occur during flow through of the core. The observed effluent concentration shows a reduction in Mg2+, while the Ca2+ concentration is increased. This, together with SEM-EDS analysis, indicates that magnesium-bearing mineral phases are precipitated leading to dissolution of calcite, an observation . This is in-line with other flow-through experiments reported earlier. The observed dissolution and precipitation are sensitive to the effective stress and test temperature. Typically. H, higher stress and temperature lead to increased concentration differences of Mg2+ and Ca2+ concentration changes.. The observed strain can be partitioned additively into a <span class="hlt">mechanical</span> and chemical driven component.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMMR13B..08R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMMR13B..08R"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in Phase D to 45 GPa and implications for the seismic anisotropy in deep subducted slabs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rosa, A. D.; Sanchez-Valle, C.; Nisr, C.; Bollinger, C.; Evans, S.; Merkel, S.</p> <p>2010-12-01</p> <p>Petrologic investigations have shown that phase D, MgSi2H2O6, may be the dominant hydrous phase along a cold slab geotherm, accounting for more than 40 vol.% of very hydrous subducted peridotites between 700 to 1300 km depth [Iwamori, 2004]. Such large volume fractions of phase D are likely to have an important impact on seismic properties in subduction zones and has been appealed to explain a number of seismic observation in subducted plates including velocity heterogeneity and high shear-wave splitting (VSH > VSV) [Chen and Brudzinki, 2003; Mainprice et al. 2007, Laurence & Wysession, 2006]. The layered structure of Phase D behaves highly anisotropic under compression and is likely to align in a non-hydrostatic stress field, being a strong candidate to contribute to the seismic shear wave splitting observed in deep subducted slabs. In order to interpret these seismic observations in terms of mineralogy, <span class="hlt">deformation</span> state and degree of hydration, precisely determined rheology and elasticity data of candidate phases at relevant pressure and temperature conditions are needed. In this contribution we present results of the plastic <span class="hlt">deformation</span> behavior of Phase D up to 45 GPa. Experiments were conducted using synchrotron radial x-ray diffraction at ESRF ID09A and a panoramic diamond anvil cell as <span class="hlt">deformation</span> apparatus. Phase D samples with three different compositions, including pure Mg-Phase D, Fe-bearing and Fe-Al-bearing Phase D, were investigated to constrain the effect of cation substitution on the <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. The samples were synthesized at 19 GPa and about 1100 °C in a multi-anvil press at ETH Zurich and confirmed to be Phase D by single-crystal x-ray diffraction and Raman spectroscopy. Recovered crystals were reduced to fine-grained powders and loaded in x-ray transparent boron gaskets for the experiments. Upon compression, the development of strong textures in the samples was observed from the intensity variations of Debye rings. The observed slip</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8583I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8583I"><span id="translatedtitle"><span class="hlt">Active</span> intraplate <span class="hlt">deformation</span> as geodynamic responses to oblique shallow subduction of a flat slab: example from central and southwest Japan</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishiyama, Tatsuya; Sato, Hiroshi</p> <p>2015-04-01</p> <p>Subduction of a flat slab has been recognized as one of the primary driving <span class="hlt">mechanism</span> of wide intracontinental subsidence farther away from the subduction leading edge in many subduction margins. In most cases, however, quantitative and qualitative limitations on chronological constraints prevent comprehensive understanding of these geodynamic linkages. In this study, we show distinct, geologic and seismic evidence for spatial and temporal correlation between plate subduction and intercontinental <span class="hlt">deformation</span>, mainly driven by dynamic interaction between subducting Philippine Sea (PHS) plate and overriding continental crusts of central and southwest Japan (Eurasian plate) along the Nankai-Tonankai subduction zone since Pliocene. Based on analyses of Pliocene to Pleistocene tectonic histories by use of rich dataset of Neogene stratigraphy, drainage network evolution, and shallow to deep seismic reflection profiles, depocenters of wide sedimentary basins and <span class="hlt">active</span> thrusting have migrated northward since ca. 5 Ma to present from forearc to backarc of the southwest Japan arc. Median tectonic line, <span class="hlt">active</span> dextral strike-slip fault as a forearc sliver along the Nankai, is located north of the upward extension of the downdip limit of the interseismic locked zone. Southwest Japan north of the MTL, underlain by the subducting slab with steady state slip (Nakanishi et al., 2002; Kodaira et al., 2004), appears tectonically less inactive than central Japan and has behaved as a less <span class="hlt">deformed</span> rigid block. Contrastingly, Quaternary <span class="hlt">active</span> intraplate <span class="hlt">deformation</span> has been prominent north of the inactive MTL above a shallow flat segment of the PHS plate along the Tonankai. Deep seismic reflection profile images upward corrugated very shallow PHS slab being contact with continental lower crust beneath <span class="hlt">actively</span> <span class="hlt">deforming</span> area. We interpreted temporal and spatial correlation of oblique subduction of the shallow and flat, corrugated PHS slab as an essential <span class="hlt">mechanical</span> role to enhance</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1237699','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1237699"><span id="translatedtitle">Room temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of alumina particles observed from in situ micro-compression and atomistic simulations.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; Mook, William M.; Bufford, Daniel Charles; Boyce, Brad L.; Hattar, Khalid Mikhiel; Kotula, Paul G.; Hall, Aaron Christopher</p> <p>2015-09-22</p> <p>Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, <span class="hlt">deform</span>, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle <span class="hlt">deformation</span> and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental <span class="hlt">mechanisms</span> responsible for plastic <span class="hlt">deformation</span>/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic <span class="hlt">deformation</span> and fracture without fragmentation. Dislocation nucleation/motion, significant plastic <span class="hlt">deformation</span>, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> provide insight into feedstock design for AD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1237699-room-temperature-deformation-mechanisms-alumina-particles-observed-from-situ-micro-compression-atomistic-simulations','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1237699-room-temperature-deformation-mechanisms-alumina-particles-observed-from-situ-micro-compression-atomistic-simulations"><span id="translatedtitle">Room temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of alumina particles observed from in situ micro-compression and atomistic simulations.</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Sarobol, Pylin; Chandross, Michael E.; Carroll, Jay D.; Mook, William M.; Bufford, Daniel Charles; Boyce, Brad L.; Hattar, Khalid Mikhiel; Kotula, Paul G.; Hall, Aaron Christopher</p> <p>2015-09-22</p> <p>Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, <span class="hlt">deform</span>, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle <span class="hlt">deformation</span> and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental <span class="hlt">mechanisms</span> responsible for plastic <span class="hlt">deformation</span>/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containingmore » numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic <span class="hlt">deformation</span> and fracture without fragmentation. Dislocation nucleation/motion, significant plastic <span class="hlt">deformation</span>, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. As a result, the identified <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> provide insight into feedstock design for AD.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JTST...25...82S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JTST...25...82S"><span id="translatedtitle">Room Temperature <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> of Alumina Particles Observed from In Situ Micro-compression and Atomistic Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sarobol, Pylin; Chandross, Michael; Carroll, Jay D.; Mook, William M.; Bufford, Daniel C.; Boyce, Brad L.; Hattar, Khalid; Kotula, Paul G.; Hall, Aaron C.</p> <p>2016-01-01</p> <p>Aerosol deposition (AD) is a solid-state deposition technology that has been developed to fabricate ceramic coatings nominally at room temperature. Sub-micron ceramic particles accelerated by pressurized gas impact, <span class="hlt">deform</span>, and consolidate on substrates under vacuum. Ceramic particle consolidation in AD coatings is highly dependent on particle <span class="hlt">deformation</span> and bonding; these behaviors are not well understood. In this work, atomistic simulations and in situ micro-compressions in the scanning electron microscope, and the transmission electron microscope (TEM) were utilized to investigate fundamental <span class="hlt">mechanisms</span> responsible for plastic <span class="hlt">deformation</span>/fracture of particles under applied compression. Results showed that highly defective micron-sized alumina particles, initially containing numerous dislocations or a grain boundary, exhibited no observable shape change before fracture/fragmentation. Simulations and experimental results indicated that particles containing a grain boundary only accommodate low strain energy per unit volume before crack nucleation and propagation. In contrast, nearly defect-free, sub-micron, single crystal alumina particles exhibited plastic <span class="hlt">deformation</span> and fracture without fragmentation. Dislocation nucleation/motion, significant plastic <span class="hlt">deformation</span>, and shape change were observed. Simulation and TEM in situ micro-compression results indicated that nearly defect-free particles accommodate high strain energy per unit volume associated with dislocation plasticity before fracture. The identified <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> provide insight into feedstock design for AD.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMEP...24.2586S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMEP...24.2586S"><span id="translatedtitle">Analysis of the <span class="hlt">Deformation</span> and Damage <span class="hlt">Mechanisms</span> of Pearlitic Steel by EBSD and "in-situ" SEM Tensile Tests</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sidhom, Habib; Yahyaoui, H.; Braham, C.; Gonzalez, G.</p> <p>2015-07-01</p> <p>The processes governing the <span class="hlt">deformation</span> and damage of C70 pearlitic steel were investigated in nanometer and micrometer scales using electron backscatter diffraction technique and "in-situ" scanning electron microscope tensile testing. The ferrite behavior was identified by "in-situ" x-ray tensile tests. Investigations were carried out on annealed microstructure with two interlamellar spacings of Sp = 170 and Sp = 230 nm. It is shown that pearlite yielding is controlled by the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> occurring in ferrite. <span class="hlt">Deformation</span> and damage <span class="hlt">mechanisms</span> were proposed. At low strain, pearlite <span class="hlt">deforms</span> homogeneously with low misorientation (<5°) inside the pearlite colonies and elongates the cementite plates. At high strain, pearlite <span class="hlt">deforms</span> heterogeneously in intense localized shear bands inside the more favorably oriented pearlite colonies. Misorientation reaches values up to 15°. Cementite <span class="hlt">deforms</span> by an offset of lamella along the shear bands. The nucleation of these shear bands occurs at strain level of E 11 = 7% for coarse pearlite and at a higher value for fine pearlite. Damage occurs by brittle fracture of the elongated cementite lamellae parallel to the tensile axis and which are developed by shear micro-cracks along the slip bands. The plastic-induced damage is thus delayed by the fine pearlite structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4761928','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4761928"><span id="translatedtitle"><span class="hlt">Mechanical</span> characterization of the P56 mouse brain under large-<span class="hlt">deformation</span> dynamic indentation</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>MacManus, David B.; Pierrat, Baptiste; Murphy, Jeremiah G.; Gilchrist, Michael D.</p> <p>2016-01-01</p> <p>The brain is a complex organ made up of many different functional and structural regions consisting of different types of cells such as neurons and glia, as well as complex anatomical geometries. It is hypothesized that the different regions of the brain exhibit significantly different <span class="hlt">mechanical</span> properties, which may be attributed to the diversity of cells and anisotropy of neuronal fibers within individual brain regions. The regional dynamic <span class="hlt">mechanical</span> properties of P56 mouse brain tissue in vitro and in situ at velocities of 0.71–4.28 mm/s, up to a <span class="hlt">deformation</span> of 70 μm are presented and discussed in the context of traumatic brain injury. The experimental data obtained from micro-indentation measurements were fit to three hyperelastic material models using the inverse Finite Element method. The cerebral cortex elicited a stiffer response than the cerebellum, thalamus, and medulla oblongata regions for all velocities. The thalamus was found to be the least sensitive to changes in velocity, and the medulla oblongata was most compliant. The results show that different regions of the mouse brain possess significantly different <span class="hlt">mechanical</span> properties, and a significant difference also exists between the in vitro and in situ brain. PMID:26898475</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NatSR...621569M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016NatSR...621569M&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Mechanical</span> characterization of the P56 mouse brain under large-<span class="hlt">deformation</span> dynamic indentation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>MacManus, David B.; Pierrat, Baptiste; Murphy, Jeremiah G.; Gilchrist, Michael D.</p> <p>2016-02-01</p> <p>The brain is a complex organ made up of many different functional and structural regions consisting of different types of cells such as neurons and glia, as well as complex anatomical geometries. It is hypothesized that the different regions of the brain exhibit significantly different <span class="hlt">mechanical</span> properties, which may be attributed to the diversity of cells and anisotropy of neuronal fibers within individual brain regions. The regional dynamic <span class="hlt">mechanical</span> properties of P56 mouse brain tissue in vitro and in situ at velocities of 0.71-4.28 mm/s, up to a <span class="hlt">deformation</span> of 70 μm are presented and discussed in the context of traumatic brain injury. The experimental data obtained from micro-indentation measurements were fit to three hyperelastic material models using the inverse Finite Element method. The cerebral cortex elicited a stiffer response than the cerebellum, thalamus, and medulla oblongata regions for all velocities. The thalamus was found to be the least sensitive to changes in velocity, and the medulla oblongata was most compliant. The results show that different regions of the mouse brain possess significantly different <span class="hlt">mechanical</span> properties, and a significant difference also exists between the in vitro and in situ brain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4291041','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4291041"><span id="translatedtitle">Elasticity of MoS2 Sheets by <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> Observed by in Situ Electron Microscopy</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>MoS2 has been the focus of extensive research due to its potential applications. More recently, the <span class="hlt">mechanical</span> properties of MoS2 layers have raised interest due to applications in flexible electronics. In this article, we show in situ transmission electron microcsopy (TEM) observation of the <span class="hlt">mechanical</span> response of a few layers of MoS2 to an external load. We used a scanning tunneling microscope (STM) tip mounted on a TEM stage to induce <span class="hlt">deformation</span> on nanosheets of MoS2 containing few layers. The results confirm the outstanding <span class="hlt">mechanical</span> properties on the MoS2. The layers can be bent close to 180°. However, when the tip is retrieved the initial structure is recovered. Evidence indicates that there is a significant bond reconstruction during the bending with an outstanding capability to recover the initial bond structure. The results show that flexibility of three layers of MoS2 remains the same as a single layer while increasing the bending modulus by 3 orders of magnitude. Our findings are consistent with theoretical calculations and confirm the great potential of MoS2 for applications. PMID:25598860</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27524104','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27524104"><span id="translatedtitle">Compensatory Cell Movements Confer Robustness to <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> during Embryonic Development.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jelier, Rob; Kruger, Angela; Swoger, Jim; Zimmermann, Timo; Lehner, Ben</p> <p>2016-08-01</p> <p>Embryonic development must proceed despite both internal molecular fluctuations and external perturbations. However, <span class="hlt">mechanisms</span> that provide robustness to <span class="hlt">mechanical</span> perturbation remain largely uncharacterized. Here, we use light-sheet microscopy, comprehensive single-cell tracking, and targeted cell ablation to study the response of Caenorhabditis elegans embryos to external compression. Compression changes the relative positions of many cells and causes severe distortions of the embryonic axes. A large-scale movement of cells then corrects this distortion. Only a few specific cells are required for these compensatory movements, and one cell, ABarppap, appears to generate force, dramatically changing as it moves to its correct local cellular environment. During these movements, we also observed "egressions", cells moving out onto the surface, and lineages that undergo both ingression and egression. In total, our work describes how the embryo responds to a major <span class="hlt">mechanical</span> <span class="hlt">deformation</span> that can occur during the early development in situ and puts forward a model to explain how the response is coordinated. PMID:27524104</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010PhDT.......293M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010PhDT.......293M"><span id="translatedtitle">Microstructural evolution and <span class="hlt">mechanical</span> properties of high strength magneisum alloys fabricated by <span class="hlt">deformation</span> processing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mansoor, Bilal</p> <p></p> <p>The goal of this research was to develop high strength Mg by thermo-<span class="hlt">mechanical</span> processing. Several novel techniques were developed to impart large plastic strains on Mg alloys and Mg based composites. The main emphasis of this work was on investigating the effect of different processing schemes on grain-refinement and texture modification of processed material. The room-temperature and elevated-temperature <span class="hlt">mechanical</span> behavior of processed-Mg was studied in detail. Biaxial corrugated pressing, also known as alternate biaxial reverse corrugation processing was applied to twin-roll cast AZ31 Mg and warm-extruded ZK60 Mg. Friction stir processing to partial depths was applied to thixomolded AM60 Mg and warm-extruded ZK60 Mg. A new process called "bending reverse-bending", was developed and applied to hot rolled AZ31-H24 Mg. A Mg/Al laminated composite was developed by hot pressing and rolling. In processed condition, Mg alloys exhibit enhancement in room-temperature strength and ductility, as well as elevated temperature formability. It was concluded that improvement in <span class="hlt">mechanical</span> properties of processed-Mg is strongly influenced by grain size and precipitates; while ductility largely depends on resulting <span class="hlt">deformation</span> textures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.7320Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.7320Y"><span id="translatedtitle">The <span class="hlt">mechanisms</span> of driving lithospheric <span class="hlt">deformation</span> in India-Asia collision zone: a perspective from 3-D numerical modeling</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yang, Jianfeng; Kaus, Boris</p> <p>2016-04-01</p> <p>The <span class="hlt">mechanism</span> of intraplate <span class="hlt">deformation</span> remains incompletely understood by plate tectonics theory. The India-Asia collision zone is the largest present-day example of continental collision, which makes it an ideal location to study the processes of continental <span class="hlt">deformation</span>. Existing models of lithospheric <span class="hlt">deformation</span> are typically quasi two-dimensional and often assume that the lithosphere is a thin viscous sheet, which <span class="hlt">deforms</span> homogeneously as a result of the collision, or flows above a partially molten lower crust, which explains the exhumation of Himalayan units and lateral spreading of Tibetan plateau. An opposing view is that most <span class="hlt">deformation</span> localize in shear zones separating less <span class="hlt">deformed</span> blocks, requiring the lithosphere to have an elasto-plastic rather than a viscous rheology. In order to distinguish which model best fits the observations we develop a 3-D visco-elasto-plastic model, which can model both distributed and highly localized <span class="hlt">deformation</span>. In our preliminary result, most of the large-scale strike-slips faults including Altyn-Tagh fault, Xianshuihe fault, Red-River fault, Sagaing fault and Jiali fault can be simulated. The topography is consistent with observations that flat plateau in central Tibet and steep, abrupt margins adjacent to Sichuan basin, and gradual topography in southeast Tibet. These models suggest that the localized large-scale strike-slip faults accommodate the continental <span class="hlt">deformation</span>. These results show the importance of a weak lower crust and topographic effects, as well as the effect of rheology and temperature structure of the lithosphere on the <span class="hlt">deformation</span> patterns.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169986','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4169986"><span id="translatedtitle">Biomaterials-Based Strategies for the Engineering of <span class="hlt">Mechanically</span> <span class="hlt">Active</span> Soft Tissues</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Tong, Zhixiang; Jia, Xinqiao</p> <p>2012-01-01</p> <p>Load-bearing, <span class="hlt">mechanically</span> <span class="hlt">active</span> tissues are routinely subjected to non-linear <span class="hlt">mechanical</span> <span class="hlt">deformations</span>. Consequently, these tissues exhibit complex <span class="hlt">mechanical</span> properties and unique tissue organizations. Successful engineering of <span class="hlt">mechanically</span> <span class="hlt">active</span> tissues relies on the integration of the <span class="hlt">mechanical</span> sensing <span class="hlt">mechanism</span> found in the native tissues into polymeric scaffolds. Intelligent biomaterials that closely mimic the structural organizations and multi-scale responsiveness of the natural extracellular matrices (ECM), when strategically combined with multipotent cells and dynamic culture devices that generate physiologically relevant physical forces, will lead to the creation of artificial tissues that are <span class="hlt">mechanically</span> robust and biologically functional. PMID:25250199</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MS%26E..103a2003A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MS%26E..103a2003A"><span id="translatedtitle">Research on geometrical model and <span class="hlt">mechanism</span> for metal <span class="hlt">deformation</span> based on plastic flow</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>An, H. P.; Rui, Z. Y.; Li, X.</p> <p>2015-12-01</p> <p>Starting with general conditions of metal plastic <span class="hlt">deformation</span>, it analyses the relation between the percentage spread and geometric parameters of a forming body with typical machining process are studied. A geometrical model of <span class="hlt">deforming</span> metal is set up according to the characteristic of a flowing metal particle. Starting from experimental results, the effect of technological parameters and friction between workpiece and dies on plastic <span class="hlt">deformation</span> of a material were studied and a slippage <span class="hlt">deformation</span> model of mass points within the material was proposed. Finally, the computing methods for strain and <span class="hlt">deformation</span> energy and temperature rise are derived from homogeneous <span class="hlt">deformation</span>. The results can be used to select technical parameters and compute physical quantities such as strain, <span class="hlt">deformation</span> energy, and temperature rise.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.T53A2695M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.T53A2695M"><span id="translatedtitle">Modern Tectonic <span class="hlt">Deformation</span> in the <span class="hlt">Active</span> Basin-And Province Northwest of Beijing, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mi, S.; Wen, X.</p> <p>2012-12-01</p> <p>Our study region is the northwest of Beijing, northern north China. The most typical extensional <span class="hlt">active</span> tectonic area of the China continent, called the <span class="hlt">active</span> basin-and-range province northwest of Beijing, exist there. This <span class="hlt">active</span> tectonic province is made up of several NE-trending Quaternary graben basins and horst ranges between basins. An about 1500-year-long written historical record has suggested that there have been no major earthquakes with magnitude 7 or greater occurred in most of the study region since AD 512. So, the characteristic of modern tectonic <span class="hlt">deformation</span> of the study region and its implication for the future seismic potential of major earthquakes are important scientific issues. In this study, based on data of regional GPS station velocities and <span class="hlt">active</span> tectonics, combining relocated earthquake distribution, we make a preliminary analysis on the characteristic of the modern tectonic <span class="hlt">deformation</span> of the study region. We design three zones across deferent segments of the <span class="hlt">active</span> basin-and-range province to analyze both the present tectonic <span class="hlt">deformation</span> from the GPS velocity profiles and the major fault's downward-extents from the relocated hypocenters. Our analyses reveal that: (1) Significant NNW-ward and SSE-ward horizontal extension exists on different segments of the <span class="hlt">active</span> basin-and-range province northwest of Beijing at rates of 2 to 3mm /yr, accompanied with right-lateral shear <span class="hlt">deformation</span> at 1 to 2mm/yr. (2) On the present tectonic <span class="hlt">deformation</span>, the southeastern margin of the Datong-Yangyuan basin, the biggest graben basin of the <span class="hlt">active</span> tectonic province, shows as a turning belt of the extensional rates, suggesting that relatively high tensile strain accumulation could exist there. (3)On the northeastern segment of the studied <span class="hlt">active</span> basin-and-range province, both the Zhangjiakou-Yanhui graben basin and the Beijing graben basin have also been being in significant extensional and shear <span class="hlt">deformation</span>. (4) The relocated hypocenter distribution have</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MMTA...46.5610A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MMTA...46.5610A"><span id="translatedtitle">Creep Behavior, <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span>, and Creep Life of Mod.9Cr-1Mo Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>ABE, Fujio</p> <p>2015-12-01</p> <p>The creep behavior, <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, and the correlation between creep <span class="hlt">deformation</span> parameters and creep life have been investigated for Mod.9Cr-1Mo steel (Gr.91, 9Cr-1Mo-VNb) by analyzing creep strain data at 723 K to 998 K (450 °C to 725 °C), 40 to 450 MPa, and t r = 11.4 to 68,755 hours in NIMS Creep Data Sheet. The time to rupture t r is reasonably correlated with the minimum creep rate {dot{\\varepsilon }}_{ min } and the acceleration of creep rate by strain in the acceleration region dln {dot{\\varepsilon }} /d ɛ, as t r = 1.5/[ {dot{\\varepsilon }}_{ min } ( dln {dot{\\varepsilon }} /d ɛ)], where {dot{\\varepsilon }}_{ min } and dln {dot{\\varepsilon }} /d ɛ reflect the creep behavior in the transient and acceleration regions, respectively. The {dot{\\varepsilon }}_{ min } is inversely proportional to the time to minimum creep rate t m, while it is proportional to the strain to minimum creep rate ɛ m, as {dot{\\varepsilon }}_{ min } = 0.54 ( ɛ m/ t m). The ɛ m decreases with decreasing stress, suggesting that the creep <span class="hlt">deformation</span> in the transient region becomes localized in the vicinity of prior austenite grain boundaries with decreasing stress. The duration of acceleration region is proportional to the duration of transient region, while the dln {dot{\\varepsilon }} /d ɛ is inversely proportional to the ɛ m. The t r is also correlated with the t m, as t r = g t m, where g is a constant. The present creep life equations reasonably predict the degradation in creep rupture strength at long times. The downward deviation takes place in the t r vs {dot{\\varepsilon }}_{ min } curves (Monkman-Grant plot). At the same {dot{\\varepsilon }}_{ min } , both the ɛ m and t m change upon the condition of t m ∝ ɛ m. The decrease in ɛ m with decreasing stress, corresponding to decreasing {dot{\\varepsilon }}_{ min } , causes a decrease in t m, indicating the downward deviation of the t r vs {dot{\\varepsilon }}_{ min } curves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PMB....52.5277X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PMB....52.5277X"><span id="translatedtitle">A <span class="hlt">deformable</span> lung tumor tracking method in fluoroscopic video using <span class="hlt">active</span> shape models: a feasibility study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xu, Qianyi; Hamilton, Russell J.; Schowengerdt, Robert A.; Jiang, Steve B.</p> <p>2007-09-01</p> <p>A dynamic multi-leaf collimator (DMLC) can be used to track a moving target during radiotherapy. One of the major benefits for DMLC tumor tracking is that, in addition to the compensation for tumor translational motion, DMLC can also change the aperture shape to conform to a <span class="hlt">deforming</span> tumor projection in the beam's eye view. This paper presents a method that can track a <span class="hlt">deforming</span> lung tumor in fluoroscopic video using <span class="hlt">active</span> shape models (ASM) (Cootes et al 1995 Comput. Vis. Image Underst. 61 38-59). The method was evaluated by comparing tracking results against tumor projection contours manually edited by an expert observer. The evaluation shows the feasibility of using this method for precise tracking of lung tumors with <span class="hlt">deformation</span>, which is important for DMLC-based real-time tumor tracking.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Tectp.661...81V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Tectp.661...81V"><span id="translatedtitle">Earthquake relocations, crustal rheology, and <span class="hlt">active</span> <span class="hlt">deformation</span> in the central-eastern Alps (N Italy)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Viganò, Alfio; Scafidi, Davide; Ranalli, Giorgio; Martin, Silvana; Della Vedova, Bruno; Spallarossa, Daniele</p> <p>2015-10-01</p> <p>A revised seismic catalogue (1994-2007) for the central-eastern Alps (N Italy) is presented. 396 earthquake relocations, for local magnitudes in the 1.2-5.3 range, are performed using a 3D crustal velocity structure and probabilistic locations. The location procedure is validated by computing a set of 41 quarry shot solutions and all the results, both about shots and seismic events, are compared with those obtained using the routine location procedure. Results are shown for five contiguous seismotectonic domains, as supported by geological and geophysical evidence (e.g., fault systems, crustal tomography, focal <span class="hlt">mechanisms</span> types). Earthquake hypocentres are mostly located in the upper crust (0-15 km of depth), in good agreement with thermo-rheological models about the brittle-ductile transitions (8-9 km of depth) and total crustal strengths (1.0-2.0 TN m- 1). Epicentres are clustered and/or aligned along present-day <span class="hlt">active</span> geological structures. The proposed seismotectonic model shows dominant compression along the Giudicarie and Belluno-Bassano-Montello thrusts, with strain partitioning along the dominant right-lateral strike-slip faults of the Schio-Vicenza domain. The present-day <span class="hlt">deformation</span> of the Southern Alps and the internal Alpine chain is compatible with Adria indentation and the related crustal stress distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..1512335B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..1512335B"><span id="translatedtitle">Synkinematic phyllosilicates in a thrust fault zone : good proxy for PT conditions, <span class="hlt">deformation</span> <span class="hlt">mechanism</span> and mass transfers (example of the Monte perdido Thrust in southern Pyrenees)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buatier, Martine; Lacroix, Brice; Trincal, Vincent; Charpentier, Delphine; Labaume, Pierre; Trave, Anna</p> <p>2013-04-01</p> <p>1.67Fe2.31Mg1.71)6(OH)8). Temperatures of chlorite formation calculated by thermodynamic models range from 210°C to 265°C. Taking into account thermometric data from fluid inclusions in calcite and quartz veins, we established that the formation of the synkinematic chlorite occurred under about 6.5km burial. These data suggest that calcite and quartz pressure solution was not the only <span class="hlt">mechanism</span> of <span class="hlt">deformation</span> but that thrust fault <span class="hlt">activity</span> induced mineralogical reactions implying partial dissolution and recrystallisation of phyllosilicates in the presence of fluid in a relatively closed system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.G11A0850J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.G11A0850J"><span id="translatedtitle">Crustal <span class="hlt">Deformation</span> around Zhangjiakou-Bohai Seismically <span class="hlt">Active</span> Belt</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, H.; Fu, G.; Kato, T.</p> <p>2011-12-01</p> <p>Zhangjiakou-Bohai belt is a seismically <span class="hlt">active</span> belt located in Northern China around Beijing, the capital of China. Near such a belt many great earthquakes occurred in the past centuries (e.g. the 1976 Tanshan Ms7.8 earthquake, the 1998 Zhangbei Ms6.2 earthquake, etc). Chinese Government established dense permanent and regional Global Positioning System (GPS) stations in and near the area. We collected and analyzed all the GPS observation data between 1999 and 2009 around Zhangjiakou-Bohai seismic belt, and obtained velocities at 143 stations. At the same time we investigated Zhangjiakou-Bohai belt slip rate for three profiles from northwest to southeast, and constructed a regional strain field on the Zhangjiakou-Bohai seismic belt region by least-square collocation. Based on the study we found that: 1) Nowadays the Zhangjiakou-Bohai seismic belt is creeping with left-lateral slip rate of 2.0mm~2.4mm/a, with coupling depth of 35~50km; 2) In total, the slip and coupling depth of the northwestern seismic belt is less than the one of southeast side; 3) The maximum shear strain is about 3×10-8 at Beijing-Tianjin-Tangshan area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1980RpSBA..14..134B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1980RpSBA..14..134B"><span id="translatedtitle">Use of polyurethane foam <span class="hlt">deformation</span> sensor to record respiratory <span class="hlt">activity</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bredov, V. I.; Baranov, V. S.</p> <p>1980-05-01</p> <p>The sensor developed has some substantial advantages over other known types. It is highly sensitive over a wide range of strain loads. The level of the output signal is linearly related to the force exerted on it, and it is sufficient for direct recording without using amplifiers of electric signals. The sensor is based on elastic, spongy material, polyurethane foam (porolon) with current-conducting material on the pore surface, current-conducting carbon black or electrode paste. The elastic properties of the sensor are built in the actual base of the strain-sensitive element, which simplifies the construction substantially and increases the reliability of the unit. In order to test the possibility of using this sensor to examine respiratory function, human pneumograms were recorded with the subject in a calm state along with the respiratory <span class="hlt">activity</span> of experimental animals (dogs). Samples of the respiratory curve are shown. The simplicity of design of the sensor makes it possible to use it in various physiological experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4569744','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4569744"><span id="translatedtitle"><span class="hlt">Mechanical</span> stress <span class="hlt">activates</span> neurites and somata of myenteric neurons</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Kugler, Eva M.; Michel, Klaus; Zeller, Florian; Demir, Ihsan E.; Ceyhan, Güralp O.; Schemann, Michael; Mazzuoli-Weber, Gemma</p> <p>2015-01-01</p> <p>The particular location of myenteric neurons, sandwiched between the 2 muscle layers of the gut, implies that their somata and neurites undergo <span class="hlt">mechanical</span> stress during gastrointestinal motility. Existence of mechanosensitive enteric neurons (MEN) is undoubted but many of their basic features remain to be studied. In this study, we used ultra-fast neuroimaging to record <span class="hlt">activity</span> of primary cultured myenteric neurons of guinea pig and human intestine after von Frey hair evoked <span class="hlt">deformation</span> of neurites and somata. Independent component analysis was applied to reconstruct neuronal morphology and follow neuronal signals. Of the cultured neurons 45% (114 out of 256, 30 guinea pigs) responded to neurite probing with a burst spike frequency of 13.4 Hz. Action potentials generated at the stimulation site invaded the soma and other neurites. Mechanosensitive sites were expressed across large areas of neurites. Many mechanosensitive neurites appeared to have afferent and efferent functions as those that responded to <span class="hlt">deformation</span> also conducted spikes coming from the soma. Mechanosensitive neurites were also <span class="hlt">activated</span> by nicotine application. This supported the concept of multifunctional MEN. 14% of the neurons (13 out of 96, 18 guinea pigs) responded to soma <span class="hlt">deformation</span> with burst spike discharge of 17.9 Hz. Firing of MEN adapted rapidly (RAMEN), slowly (SAMEN), or ultra-slowly (USAMEN). The majority of MEN showed SAMEN behavior although significantly more RAMEN occurred after neurite probing. Cultured myenteric neurons from human intestine had similar properties. Compared to MEN, dorsal root ganglion neurons were <span class="hlt">activated</span> by neurite but not by soma <span class="hlt">deformation</span> with slow adaptation of firing. We demonstrated that MEN exhibit specific features very likely reflecting adaptation to their specialized functions in the gut. PMID:26441520</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26441520','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26441520"><span id="translatedtitle"><span class="hlt">Mechanical</span> stress <span class="hlt">activates</span> neurites and somata of myenteric neurons.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kugler, Eva M; Michel, Klaus; Zeller, Florian; Demir, Ihsan E; Ceyhan, Güralp O; Schemann, Michael; Mazzuoli-Weber, Gemma</p> <p>2015-01-01</p> <p>The particular location of myenteric neurons, sandwiched between the 2 muscle layers of the gut, implies that their somata and neurites undergo <span class="hlt">mechanical</span> stress during gastrointestinal motility. Existence of mechanosensitive enteric neurons (MEN) is undoubted but many of their basic features remain to be studied. In this study, we used ultra-fast neuroimaging to record <span class="hlt">activity</span> of primary cultured myenteric neurons of guinea pig and human intestine after von Frey hair evoked <span class="hlt">deformation</span> of neurites and somata. Independent component analysis was applied to reconstruct neuronal morphology and follow neuronal signals. Of the cultured neurons 45% (114 out of 256, 30 guinea pigs) responded to neurite probing with a burst spike frequency of 13.4 Hz. Action potentials generated at the stimulation site invaded the soma and other neurites. Mechanosensitive sites were expressed across large areas of neurites. Many mechanosensitive neurites appeared to have afferent and efferent functions as those that responded to <span class="hlt">deformation</span> also conducted spikes coming from the soma. Mechanosensitive neurites were also <span class="hlt">activated</span> by nicotine application. This supported the concept of multifunctional MEN. 14% of the neurons (13 out of 96, 18 guinea pigs) responded to soma <span class="hlt">deformation</span> with burst spike discharge of 17.9 Hz. Firing of MEN adapted rapidly (RAMEN), slowly (SAMEN), or ultra-slowly (USAMEN). The majority of MEN showed SAMEN behavior although significantly more RAMEN occurred after neurite probing. Cultured myenteric neurons from human intestine had similar properties. Compared to MEN, dorsal root ganglion neurons were <span class="hlt">activated</span> by neurite but not by soma <span class="hlt">deformation</span> with slow adaptation of firing. We demonstrated that MEN exhibit specific features very likely reflecting adaptation to their specialized functions in the gut. PMID:26441520</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT........51T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT........51T"><span id="translatedtitle">High temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of L12-containing Co-based superalloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Titus, Michael Shaw</p> <p></p> <p>Ni-based superalloys have been used as the structural material of choice for high temperature applications in gas turbine engines since the 1940s, but their operating temperature is becoming limited by their melting temperature (Tm =1300degrees C). Despite decades of research, no viable alternatives to Ni-based superalloys have been discovered and developed. However, in 2006, a ternary gamma' phase was discovered in the Co-Al-W system that enabled a new class of Co-based superalloys to be developed. These new Co-based superalloys possess a gamma-gamma' microstructure that is nearly identical to Ni-based superalloys, which enables these superalloys to achieve extraordinary high temperature <span class="hlt">mechanical</span> properties. Furthermore, Co-based alloys possess the added benefit of exhibiting a melting temperature of at least 100degrees C higher than commercial Ni-based superalloys. Superalloys used as the structural materials in high pressure turbine blades must withstand large thermomechanical stresses imparted from the rotating disk and hot, corrosive gases present. These stresses induce time-dependent plastic <span class="hlt">deformation</span>, which is commonly known as creep, and new superalloys must possess adequate creep resistance over a broad range of temperature in order to be used as the structural materials for high pressure turbine blades. For these reasons, this research focuses on quantifying high temperature creep properties of new gamma'-containing Co-based superalloys and identifying the high temperature creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. The high temperature creep properties of new Co- and CoNi-based alloys were found to be comparable to Ni-based superalloys with respect to minimum creep rates and creep-rupture lives at 900degrees C up to the solvus temperature of the gamma' phase. Co-based alloys exhibited a propensity for extended superlattice stacking fault formation in the gamma' precipitates resulting from dislocation shearing events. When Ni was added to the Co-based compositions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6434E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6434E"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> of the Congo intracratonic basin and its eastern margin</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Everaerts, Michel; Delvaux, Damien; Beoka, Ateba</p> <p>2015-04-01</p> <p>The Congo basin, one of the largest intracontinental sedimentary basin in the world, developed in Central Africa since the early Neoproterozoic during successive tectonically controlled stages. It formed over an heterogeneous basement as highlighted by aeromagnetic data, composed of Archean cores welded by Proterozoic mobile belts. It contains an average of 4 km and locally up to 8 km of Neoproterozoic to Mesozoic sediments. Since late Mesozoic (Cenomanian), it was submitted to intraplate stresses due to the action of ridge-push forces related to the spreading of the South Atlantic. As a result, most part of the basin entered in an erosional stage while only a small part is still accumulating sediments. <span class="hlt">Active</span> <span class="hlt">deformation</span> of this vast region (5°N-11°S and 12-27°E) is indicated by a certain level of seismic <span class="hlt">activity</span>, with about 270 earthquakes instrumentally recorded with magnitudes ranging from 2.2 to 5.5 inside the basin and up to up to 6.3 along its NW (Gabon) and NW (Katanga) margins. The dozen available focal <span class="hlt">mechanisms</span> indicate that the basin is under ENE-WSW horizontal compression, under a compressional regime in its center and strike-slip regime along its northern and western margins. Low-angle slickensided fault planes are observed in the Samba cored well, constraining the onset of the recent compressional setting in the late Albian, at a time when South America was already separated from Africa and the South Atlantic Ridge was already functioning. Although subtle, recent tectonic <span class="hlt">deformations</span> (faulting and buckling undulations) can also be inferred from the reflection seismic profiles and the topography and river network. The overall neotectonic picture is inferred as reflecting the development of compressional tectonic instabilities in the basin fill and its margins under the action of intraplate stress field and the control of the basement heterogeneity. This is a contribution to preparation of the Seismotectonic Map of Africa by the working group of</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8534P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8534P"><span id="translatedtitle"><span class="hlt">Deformation</span> of the Calabrian Arc subduction complex and its relation to STEP <span class="hlt">activity</span> at depth.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Polonia, Alina; Wortel, Rinus; Nijholt, Nicolai; Govers, Rob; Torelli, Luigi</p> <p>2015-04-01</p> <p>Propagating tear faults at the edge of subducted slabs ("Subduction transform edge propagator", STEP) are an intrinsic part of lithospheric plate dynamics. The surface expression of a STEP is generally not known yet, and is expected to vary significantly from one region to the other. We choose the Sicily -Calabria-Ionian Sea region, of which the lithosphere-upper mantle structure has the characteristics of a STEP zone, as a study area. The area has a very prominent accretionary wedge, the formation and subsequent <span class="hlt">deformation</span> of which presumably were affected by the STEP <span class="hlt">activity</span> at depth. In this contribution, we use seismic data on the near surface structure and <span class="hlt">deformation</span> in combination with numerical model results to investigate the relation between deep STEP <span class="hlt">activity</span> and near surface expression. Prominent features in the surface tectonics are the Malta escarpment (with predominantly normal faulting), the newly identified Ionian Fault and Alfeo-Etna fault system, and a distinct longitudinal division of the wedge into a western and an eastern lobe (Polonia et al., Tectonics, 2011). The two lobes are characterized by different structural style, <span class="hlt">deformation</span> rates and basal detachment depths. Numerical model results indicate that the regional lithospheric structure, such as the orientation of the eastern passive (albeit subsequently <span class="hlt">activated</span>) margin of Sicily relative to the Calabrian subduction zone, has a profound effect on possible fault <span class="hlt">activity</span> along the Malta escarpment. Fault <span class="hlt">activity</span> along the above primary fault structures may have varied in time, implying the possibility of intermittent <span class="hlt">activity</span>. Interpreting seismicity in the context of a possible STEP, and the accompanying <span class="hlt">deformation</span> zone at or near the surface, is not (yet) straightforward. Although direct evidence for recognizing all aspects of STEP <span class="hlt">activity</span> is - as usual - lacking, a comparison with two well-known STEP regions, the northern part of the Tonga subduction zone and southern part of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJCMS...450008A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJCMS...450008A"><span id="translatedtitle">Experimental and computational simulation studies on creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a novel nanostructured Cu and Cu-10%Sn Alloy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abo-Elsoud, Mohamed A.</p> <p>2015-04-01</p> <p>This work presents experimental and computational simulation studies on creep <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of a novel nanostructured Cu and Cu-10%Sn alloy that prepared by <span class="hlt">mechanical</span> alloying (MA) copper with elemental Tin. <span class="hlt">Mechanical</span> Newtonian creep model is employed for computational simulation of creep <span class="hlt">deformation</span> <span class="hlt">mechanism</span> under low stress-high temperature and to justify the experimental findings. The observed behaviors are discussed and compared with the predications of the Nabarro-Herring (N-H) theory of directional diffusion. A simple theory based on the climb controlled generation of dislocations from a fixed density of sources is developed to explain the observed behavior. TEM and SEM investigations are convenient and powerful techniques for characterization of phases and a novel nano-grain structured of the resulting materials. The reduction of grain size to the nanometer scale improves their <span class="hlt">mechanical</span> properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22751262','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22751262"><span id="translatedtitle"><span class="hlt">Mechanical</span> behavior and interphase structure in a silica-polystyrene nanocomposite under uniaxial <span class="hlt">deformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rahimi, Mohammad; Iriarte-Carretero, Irene; Ghanbari, Azadeh; Böhm, Michael C; Müller-Plathe, Florian</p> <p>2012-08-01</p> <p>The <span class="hlt">mechanical</span> behavior of polystyrene and a silica-polystyrene nanocomposite under uniaxial elongation has been studied using a coarse-grained molecular dynamics technique. The Young's modulus, the Poisson ratio and the stress-strain curve of polystyrene have been computed for a range of temperatures, below and above the glass transition temperature. The predicted temperature dependence of the Young's modulus of polystyrene is compared to experimental data and predictions from atomistic simulations. The observed <span class="hlt">mechanical</span> behavior of the nanocomposite is related to the local structure of the polymer matrix around the nanoparticles. Local segmental orientational and structural parameters of the <span class="hlt">deforming</span> matrix have been calculated as a function of distance from nanoparticle's surface. A thorough analysis of these parameters reveals that the segments close to the silica nanoparticle's surface are stiffer than those in the bulk. The thickness of the nanoparticle-matrix interphase layer is estimated. The Young's modulus of the nanocomposite has been obtained for several nanoparticle volume fractions. The addition of nanoparticles results in an enhanced Young's modulus. A linear relation describes adequately the dependence of Young's modulus on the nanoparticle volume fraction. PMID:22751262</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012Nanot..23D5702R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012Nanot..23D5702R"><span id="translatedtitle"><span class="hlt">Mechanical</span> behavior and interphase structure in a silica-polystyrene nanocomposite under uniaxial <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rahimi, Mohammad; Iriarte-Carretero, Irene; Ghanbari, Azadeh; Böhm, Michael C.; Müller-Plathe, Florian</p> <p>2012-08-01</p> <p>The <span class="hlt">mechanical</span> behavior of polystyrene and a silica-polystyrene nanocomposite under uniaxial elongation has been studied using a coarse-grained molecular dynamics technique. The Young’s modulus, the Poisson ratio and the stress-strain curve of polystyrene have been computed for a range of temperatures, below and above the glass transition temperature. The predicted temperature dependence of the Young’s modulus of polystyrene is compared to experimental data and predictions from atomistic simulations. The observed <span class="hlt">mechanical</span> behavior of the nanocomposite is related to the local structure of the polymer matrix around the nanoparticles. Local segmental orientational and structural parameters of the <span class="hlt">deforming</span> matrix have been calculated as a function of distance from nanoparticle’s surface. A thorough analysis of these parameters reveals that the segments close to the silica nanoparticle’s surface are stiffer than those in the bulk. The thickness of the nanoparticle-matrix interphase layer is estimated. The Young’s modulus of the nanocomposite has been obtained for several nanoparticle volume fractions. The addition of nanoparticles results in an enhanced Young’s modulus. A linear relation describes adequately the dependence of Young’s modulus on the nanoparticle volume fraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003EAEJA.....4503B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003EAEJA.....4503B&link_type=ABSTRACT"><span id="translatedtitle">About <span class="hlt">mechanisms</span> of tetonic <span class="hlt">activity</span> of the satellites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barkin, Yu. V.</p> <p>2003-04-01</p> <p>ABOUT <span class="hlt">MECHANISMS</span> OF TECTONIC <span class="hlt">ACTIVITY</span> OF THE SATELLITES Yu.V. Barkin Sternberg Astronomical Institute, Moscow, Russia, barkin@sai.msu.ru Due to attraction of the central planet and others external bodies satellite is subjected by tidal and non-tidal <span class="hlt">deformations</span>. Elastic energy is changed in dependence from mutual position and motion of celestial bodies and as result the tensional state of satellite and its tectonic (endogenous) <span class="hlt">activity</span> also is changed. Satellites of the planets have the definite shell’s structure and due to own rotation these shells are characterized by different oblatenesses. Gravitational interaction of the satellite and its mother planet generates big additional <span class="hlt">mechanical</span> forces (and moments) between the neighboring non-spherical shells of the satellite (mantle, core and crust). These forces and moments are cyclic functions of time, which are changed in the different time-scales. They generate corresponding cyclic perturbations of the tensional state of the shells, their <span class="hlt">deformations</span>, small relative transnational displacements and slow rotation of the shells and others. In geological period of time it leads to a fundamental tectonic reconstruction of the body. Definite contribution to discussed phenomena are caused by classical tidal <span class="hlt">mechanism</span>. of planet-satellite interaction. But in this report we discuss in first the new <span class="hlt">mechanisms</span> of endogenous <span class="hlt">activity</span> of celestial bodies. They are connected with differential gravitational attraction of non-spherical satellite shells by the external celestial bodies which leads: 1) to small relative rotation (nutations) of the shells; 2) to small relative translational motions of the shells (displacements of their center of mass); 3) to relative displacements and rotations of the shells due to eccentricity of their center of mass positions; 4) to viscous elastic <span class="hlt">deformations</span> of the shells and oth. (Barkin, 2001). For higher evaluations of the power of satellite endogenous <span class="hlt">activities</span> were obtained</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUSM.V51A..01W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUSM.V51A..01W"><span id="translatedtitle">Gravity and <span class="hlt">deformation</span> changes at two persistently <span class="hlt">active</span> volcanoes: Insights into magmatic processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Williams-Jones, G.; Rymer, H.</p> <p>2004-05-01</p> <p>Insights on some of the <span class="hlt">mechanisms</span> responsible for persistent volcanism can be best achieved through the synergy of temporal geophysical and geochemical data sets. Gravity changes combined with ground <span class="hlt">deformation</span> have been shown to provide important information on magma reservoir mass changes while measurements of gas flux have been influential in determining the rate of magma emplacement. The integration of long-term micro-gravity and ground <span class="hlt">deformation</span> data with SO2 flux and total sulphur budgets collected at Poás and Masaya volcanoes (since 1983 and 1993, respectively) now allows for the identification of significant cycles of <span class="hlt">activity</span>. Recent eruptive <span class="hlt">activity</span> at Poás volcano (Costa Rica) has been characterised by the disappearance and subsequent reappearance of the summit crater lake following intrusive episodes in 1980 and 1986-1989. Magma approached the surface on both occasions and was detected by the observation of concurrent increases in micro-gravity. These increases can be best modelled in terms of brittle fracturing of a shallow magma carapace allowing magma ascent through the conduit system to beneath the crater. This process allows for the vertical transfer of heat and gas and is driven by convection of buoyant, volatile-rich magma displacing colder, degassed magma. As magma pressure drops, the connection between the deeper magma reservoir and shallow conduit system is severed allowing the hydrothermal system to resume its role as a cooling <span class="hlt">mechanism</span>. In contrast, recent <span class="hlt">activity</span> at Masaya volcano (Nicaragua) has been characterised by repeated periods of significant passive degassing (>2000 t/d SO2) with the eruption of only negligible amounts of juvenile material. The resulting cycle gravity and gas flux variations is clearly not driven by intrusion of additional magma into the shallow system. Rather, it may be due in part to blocking and gas accumulation caused by restrictions in the shallow volcano substructure. However, as with Poás, this</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014MMTA...45.2389K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014MMTA...45.2389K"><span id="translatedtitle">Stored <span class="hlt">Mechanical</span> Work in Inhomogeneous <span class="hlt">Deformation</span> Processes of a Pd-Based Bulk Metallic Glass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Küchemann, Stefan; Wagner, Hannes; Schwabe, Moritz; Bedorf, Dennis; Arnold, Walter; Samwer, Konrad</p> <p>2014-05-01</p> <p>We investigated the effect of anelastic rearrangements in a Pd-based metallic glass during inhomogeneous plastic <span class="hlt">deformation</span> producing shear bands at room temperature. Therefore, we subjected bulk metallic glasses to uniaxial stresses and characterized the influence of <span class="hlt">deformation</span> on the global configurational energy state with ultrasonic and calorimetric methods. The results provide evidence that even in an inhomogeneous plastic <span class="hlt">deformation</span> process at room temperature, a certain amount of energy can be stored which is thermally relaxed below the glass transition temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22097098','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22097098"><span id="translatedtitle">Chemopreventive <span class="hlt">activity</span> of sesquiterpene lactones (SLs) from yacon against TPA-induced Raji cells <span class="hlt">deformation</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Siriwan, D; Miyawaki, C; Miyamoto, T; Naruse, T; Okazaki, K; Tamura, H</p> <p>2011-05-15</p> <p>Yacon is a medicinal plant used as a traditional medicine by the natives in South America. In Japan, it becomes popular as a health food. Sesquiterpene Lactones (SLs) from yacon leaves were investigated and the <span class="hlt">active</span> SLs such as enhydrin, uvedalin and sonchifolin, bearing alpha-methylene-gamma-lactone and epoxides as the <span class="hlt">active</span> functional groups, were identified by 1H-6000 MHz-NMR. Chemopreventive and cytotoxic <span class="hlt">activities</span> were determined using different primary screening methods. In this study, all tested SLs strongly inhibited TPA-induced <span class="hlt">deformed</span> of Raji cells. The IC50 values of yacon SLs from anti-<span class="hlt">deforming</span> assay were 0.04-0.4 microM. Interestingly, yacon SLs showed more potential of chemo preventive <span class="hlt">activity</span> than both curcumin and parthenolide. However, the cytotoxicity on Raji cells was observed at high concentration of yacon SLs. The degree of anti-<span class="hlt">deformation</span> was ranked in order: enhydrin >uvedalin >sonchifolin >parthenolide >curcumin. As according to structure-<span class="hlt">activity</span> relationship, the high <span class="hlt">activities</span> of enhydrin, uvedalin and sonchifolin may be due to the 2-methyl-2-butenoate and its epoxide moiety. PMID:22097098</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Tectp.680..174L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Tectp.680..174L"><span id="translatedtitle">Microstructures, <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and seismic properties of a Palaeoproterozoic shear zone: The Mertz shear zone, East-Antarctica</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lamarque, Gaëlle; Bascou, Jérôme; Maurice, Claire; Cottin, Jean-Yves; Riel, Nicolas; Ménot, René-Pierre</p> <p>2016-06-01</p> <p>The Mertz shear zone (MSZ) is a lithospheric scale structure that recorded mid-crustal <span class="hlt">deformation</span> during the 1.7 Ga orogeny. We performed a microstructural and crystallographic preferred orientation (CPO) study of samples from both mylonites and tectonic boudins that constitute relics of the Terre Adélie Craton (TAC). The <span class="hlt">deformation</span> is highly accommodated in the MSZ by anastomosed shear bands, which become more scattered elsewhere in the TAC. Most of the MSZ amphibolite-facies mylonites display similar CPO, thermal conditions, intensity of <span class="hlt">deformation</span> and dominant shear strain. Preserved granulite-facies boudins show both coaxial and non-coaxial strains related to the previous 2.45 Ga event. This former <span class="hlt">deformation</span> is more penetrative and less localized and shows a <span class="hlt">deformation</span> gradient, later affected by a major phase of recrystallization during retrogression at 2.42 Ga. Both MSZ samples and granulite-facies tectonic boudins present microstructures that reflect a variety of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> associated with the rock creep that induce contrasted CPO of minerals (quartz, feldspar, biotite, amphibole and orthopyroxene). In particular, we highlight the development of an "uncommon" CPO in orthopyroxene from weakly <span class="hlt">deformed</span> samples characterized by (010)-planes oriented parallel to the foliation plane, [001]-axes parallel to the stretching lineation and clustering of [100]-axes near the Y structural direction. Lastly, we computed the seismic properties of the amphibolite and granulite facies rocks in the MSZ area in order to evaluate the contribution of the <span class="hlt">deformed</span> intermediate and lower continental crust to the seismic anisotropy recorded above the MSZ. Our results reveal that (i) the low content of amphibole and biotite in the rock formations of the TAC, and (ii) the interactions between the CPO of the different mineralogical phases, generate a seismically isotropic crust. Thus, the seismic anisotropy recorded by the seismic stations of the TAC, including the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012SPIE.8442E..20L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012SPIE.8442E..20L"><span id="translatedtitle">Space <span class="hlt">active</span> optics: performance of a <span class="hlt">deformable</span> mirror for in-situ wave-front correction in space telescopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laslandes, Marie; Hourtoule, Claire; Hugot, Emmanuel; Ferrari, Marc; Lopez, Céline; Devilliers, Christophe; Liotard, Arnaud; Chazallet, Frederic</p> <p>2012-09-01</p> <p>MADRAS (Mirror <span class="hlt">Active</span>, <span class="hlt">Deformable</span> and Regulated for Applications in Space) project aims at demonstrating the interest of <span class="hlt">Active</span> Optics for space applications. We present the prototype of a 24 actuators, 100 mm diameter <span class="hlt">deformable</span> mirror to be included in a space telescope's pupil relay to compensate for large lightweight primary mirror <span class="hlt">deformation</span>. The mirror design has been optimized with Finite Element Analysis and its experimental performance characterized in representative conditions. The developed <span class="hlt">deformable</span> mirror provides an efficient wave-front correction with a limited number of actuators and a design fitting space requirements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IJEaS.104.1277S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IJEaS.104.1277S"><span id="translatedtitle">Types of soft-sediment <span class="hlt">deformation</span> structures in a lacustrine Ploužnice member (Stephanian, Gzhelian, Pennsylvanian, Bohemian Massif), their timing, and possible trigger <span class="hlt">mechanism</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stárková, Marcela; Martínek, Karel; Mikuláš, Radek; Rosenau, Nicholas</p> <p>2015-07-01</p> <p>The succession of Stephanian C lacustrine and fluvial facies of the Ploužnice member (Semily Formation) paleolake in the Krkonoše Piedmont Basin (northern Czech Republic) preserved in borehole Sm-1 shows five types of soft-sediment <span class="hlt">deformation</span> structures (SSDS): (1) sediment injections (clastic dikes), (2) load structures and ball-and-pillow structures, (3) water-escape structures (discontinuous laminations, <span class="hlt">deformed</span> wavy bedding, recumbent folding, and dish or pillar structures), (4) <span class="hlt">deformations</span> by growth of carbonate and silica minerals during diagenesis, and (5) bioturbation. Bioturbations disturbing <span class="hlt">mechanical</span> SSDS suggest that soft-sediment <span class="hlt">deformations</span> may occur syndepositionally or soon after deposition. The discussed <span class="hlt">mechanical</span> SSDS are developed in a lacustrine environment, most being in lower shoreface and offshore facies. The <span class="hlt">mechanical</span> SSDS found in the Ploužnice lake deposits occur in all lacustrine facies associations (290 SSDS horizons in a 67-m-thick succession). The cumulative thickness in cm of <span class="hlt">mechanical</span> SSDS horizons per meter of thickness (ratio cm SSDS/m) is the highest in lower shoreface facies where it reaches from 50 up to 59.7 cm SSDS/m. Offshore facies association reaches 44 cm SSDS/m. Upper shoreface facies associations have 25.9 and 26.0 cm SSDS/m, while nearshore/mudflat facies associations preserve from 22.5 to 20.5 cm SSDS/m, and in palustrine carbonate, 13.5 cm <span class="hlt">mechanical</span> SSDS/m was found. SSDS in fluvial facies are rare (2.9 cm SSDS/m). The distribution of SSDS in the Sm-1 borehole shows clear relationships to sedimentary facies and processes such as density flows or fluctuation of water level. The relationships of particular structures indicate a relative timing of formation which is as follows: sediment deposition was followed by the formation of <span class="hlt">mechanical</span> SSDS, then by bioturbation, and finally by <span class="hlt">deformations</span> due to early diagenetic growth of carbonates and silica. The distribution of SSDS in vertical sections and their</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22492563','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22492563"><span id="translatedtitle">The <span class="hlt">deformation</span> and acoustic emission of aluminum-magnesium alloy under non-isothermal thermo-<span class="hlt">mechanical</span> loading</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Makarov, S. V.; Plotnikov, V. A. Lysikov, M. V.; Kolubaev, E. A.</p> <p>2015-10-27</p> <p>The following study investigates the <span class="hlt">deformation</span> behavior and acoustic emission in aluminum-magnesium alloy under conditions of non-isothermal thermo-<span class="hlt">mechanical</span> loading. The accumulation of <span class="hlt">deformation</span> in the alloy, in conditions of change from room temperature to 500°C, occurs in two temperature intervals (I, II), characterized by different rates of <span class="hlt">deformation</span>. The rate of <span class="hlt">deformation</span> accumulation is correlated with acoustic emission. With load increasing in cycles from 40 to 200 MPa, the value of the boundary temperature (T{sub b}) between intervals I and II changes non-monotonically. In cycles with load up to 90 MPa, the T{sub b} value increases, while an increase up to 200 MPa makes T{sub b} shift toward lower temperatures. This suggests that the shift of boundaries in the region of low temperatures and the appearance of high-amplitude pulses of acoustic emission characterize the decrease of the magnitude of thermal fluctuations with increasing <span class="hlt">mechanical</span> load, leading to the rupture of interatomic bonds in an elementary <span class="hlt">deformation</span> act.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009PhDT.......200G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009PhDT.......200G"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in advanced structural ceramics due to indentation and scratch processes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ghosh, Dipankar</p> <p></p> <p>Plasma pressure compaction technique was used to develop boron carbide (B4C) and zirconium diboride-silicon carbide (ZrB2-SiC) composite. B4C ceramics are extensively used as body armor in military and civilian applications, and ZrB2-SiC composite has been recognized as a potential candidate for high-temperature aerospace applications. In this dissertation, processing parameters, quasistatic and high-strain rate <span class="hlt">mechanical</span> response, and fundamental <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of these materials have been investigated. In the case of B4C, the rate sensitivity of indentation hardness was determined using a dynamic indentation hardness tester that can deliver loads in 100 micros. By comparing dynamic hardness with the static hardness, it was found that B4C exhibits a lower hardness at high-strain rate, contrary to known behavior in many structural ceramics. However, these results are consistent with the ballistic testing of B4C armors as reported in recent literature. This behavior was further investigated using a series of spectroscopic techniques such as visible and UV micro-Raman, photoluminescence and infrared. These studies not only confirmed that structural transformation occurred during indentation experiments similar to that in ballistic testing of B4C but also suggested a greater degree of structural changes under dynamic loading compared to static loading. Due to the potential application as external heat shields in supersonic vehicles, scratch studies were conducted on the ZrB2-SiC composite. These studies revealed metal-like slip-line patterns which are indeed an unusual in brittle solids at room-temperature. Utilizing classical stress field solutions under combined normal and tangential loads, a rationale was developed for understanding the formation of scratch-induced <span class="hlt">deformation</span> features. Also, an analytical framework was developed, combining the concept of 'blister field' and the 'secular equation' relating Raman peaks to strain, to measure scratch</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1258282-characterization-modeling-mechanical-behavior-single-crystal-titanium-deformed-split-hopkinson-pressure-bar','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1258282-characterization-modeling-mechanical-behavior-single-crystal-titanium-deformed-split-hopkinson-pressure-bar"><span id="translatedtitle">Characterization and modeling of <span class="hlt">mechanical</span> behavior of single crystal titanium <span class="hlt">deformed</span> by split-Hopkinson pressure bar</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Morrow, B. M.; Lebensohn, R. A.; Trujillo, C. P.; Martinez, D. T.; Addessio, F. L.; Bronkhorst, C. A.; Lookman, T.; Cerreta, E. K.</p> <p>2016-07-01</p> <p>Single crystal titanium samples were dynamically loaded using split-Hopkinson pressure bar (SHPB) and the resulting microstructures were examined. Characterization of the twins and dislocations present in the microstructure was conducted to understand the pathway for observed <span class="hlt">mechanical</span> behavior. Electron backscatter diffraction (EBSD) was used to measure textures and quantify twinning. Microstructures were profusely twinned after loading, and twin variants and corresponding textures were different as a function of initial orientation. Focused ion beam (FIB) foils were created to analyze dislocation content using transmission electron microscopy (TEM). Large amounts of dislocations were present, indicating that plasticity was achieved through slip andmore » twinning together. Viscoplastic self-consistent (VPSC) modeling was used to confirm the complex order of operations during <span class="hlt">deformation</span>. The <span class="hlt">activation</span> of different <span class="hlt">mechanisms</span> was highly dependent upon crystal orientation. For [0001] and View the MathML source[101¯1]-oriented crystals, compressive twinning was observed, followed by secondary tensile twinning. Furthermore, dislocations though prevalent in the microstructure, contributed to final texture far less than twinning.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MS%26E..119a2021L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MS%26E..119a2021L"><span id="translatedtitle">Analysis of the thermo-<span class="hlt">mechanical</span> <span class="hlt">deformations</span> in a hot forging tool by numerical simulation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>L-Cancelos, R.; Varas, F.; Martín, E.; Viéitez, I.</p> <p>2016-03-01</p> <p>Although programs have been developed for the design of tools for hot forging, its design is still largely based on the experience of the tool maker. This obliges to build some test matrices and correct their errors to minimize distortions in the forged piece. This phase prior to mass production consumes time and material resources, which makes the final product more expensive. The forging tools are usually constituted by various parts made of different grades of steel, which in turn have different <span class="hlt">mechanical</span> properties and therefore suffer different degrees of strain. Furthermore, the tools used in the hot forging are exposed to a thermal field that also induces strain or stress based on the degree of confinement of the piece. Therefore, the <span class="hlt">mechanical</span> behaviour of the assembly is determined by the contact between the different pieces. The numerical simulation allows to analyse different configurations and anticipate possible defects before tool making, thus, reducing the costs of this preliminary phase. In order to improve the dimensional quality of the manufactured parts, the work presented here focuses on the application of a numerical model to a hot forging manufacturing process in order to predict the areas of the forging die subjected to large <span class="hlt">deformations</span>. The thermo-<span class="hlt">mechanical</span> model developed and implemented with free software (Code-Aster) includes the strains of thermal origin, strains during forge impact and contact effects. The numerical results are validated with experimental measurements in a tooling set that produces forged crankshafts for the automotive industry. The numerical results show good agreement with the experimental tests. Thereby, a very useful tool for the design of tooling sets for hot forging is achieved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.9408R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.9408R"><span id="translatedtitle">Digital Image Correlation and Finite Element Simulations Applied to the Analysis of the <span class="hlt">Mechanisms</span> of Plastic <span class="hlt">Deformation</span> of Synthetic Halite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Raphanel, J.; Bourcier, M.; Dimanov, A.; Héripré, E.; Bornert, M.</p> <p>2012-04-01</p> <p>Synthetic halite elaborated with different microstructures ( i.e. grain sizes and grain size distribution) has been <span class="hlt">deformed</span> by uniaxial compression in a scanning electron microscope, with measure of the grain orientations, surface observation of slip lines, digital image correlation (DIC) to provide full-field estimates of displacements and surface strains (Bourcier et al. 2012). These kinematic data have indicated that the plastic <span class="hlt">deformation</span> of halite is mostly intragranular for samples with large grains, with a few grain boundaries experiencing glide. In many cases, the slip planes can be identified, with contrasted situations: cross slip, partition of grains into several parts showing different slip lines... DIC shows that intragranular strains are organized by bands which orientation may often be explained in terms of slip plane traces and which become denser as the strain magnitudes increase. In order to complete the analysis, the knowledge of the local stresses is needed. Since they cannot be measured directly, one turns to numerical simulations based on a Crystal Plasticity Finite Element Code (CPFE). The core of such codes is the description of the single crystal behavior. Salt and ionic crystals have been extensively studied in the past (Carter and Heard, 1970) and recently revisited (Picard et al., 2012). It has been established that the glide directions are <110> directions and that the glide planes are {110}, {100} and {111} with strongly temperature dependent initial critical shear stresses (CSS) and hardening behaviors. At room temperature, the {110}<110> systems have the lowest CSS but do not suffice to accommodate a general plastic strain, so there is an initial stress differential build up between a grain well-oriented for easy plastic glide and another "hard" grain until other systems are <span class="hlt">activated</span> or another <span class="hlt">deformation</span> <span class="hlt">mechanism</span> arises. The structure on which these computations are performed is another key element : one has to reconstruct a 3D</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713167H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713167H"><span id="translatedtitle">Persistent inflation at Aira caldera accompanying explosive <span class="hlt">activity</span> at Sakurajima volcano: Constraining <span class="hlt">deformation</span> source parameters from Finite Element inversions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hickey, James; Gottsmann, Jo; Iguchi, Masato; Nakamichi, Haruhisa</p> <p>2015-04-01</p> <p>Aira caldera is located within Kagoshima Bay at the southern end of Kyushu, Japan. Sakurajima is an <span class="hlt">active</span> post-caldera andesitic stratovolcano that sits on the caldera's southern rim. Despite frequent Vulcanian-type explosive <span class="hlt">activity</span>, the area is experiencing continued uplift at a maximum rate of approximately 1.5 cm/yr with a footprint of 40 km, indicating that magma is being supplied faster than it is erupted. This is of particular concern as the amplitude of <span class="hlt">deformation</span> is approaching the level inferred prior to the 1914 VEI 4 eruption. Using GPS data from 1996 - 2007 we explore causes for the uplift. To solve for the optimum <span class="hlt">deformation</span> source parameters we use an inverse Finite Element method accounting for three-dimensional material heterogeneity (inferred from seismic tomography) and the surrounding topography of the region. The same inversions are also carried out using Finite Element models that incorporate simplified homogeneous or one-dimensional subsurface material properties, with and without topography. Results from the comparison of the six different models show statistically significant differences in the inferred <span class="hlt">deformation</span> sources. This indicates that both subsurface heterogeneity and surface topography are essential in geodetic modelling to extract the most realistic <span class="hlt">deformation</span> source parameters. The current best-fit source sits within a seismic low-velocity zone in the north-east of the caldera at a depth of approximately 14 km with a volume increase of 1.2 x 108 m3. The source location underlies a region of <span class="hlt">active</span> underwater fumaroles within the Wakamiko crater and differs significantly from previous analytical modelling results. Seismic data further highlights areas of high seismic attenuation as well as large aseismic zones, both of which could allude to inelastic behaviour and a significant heat source at depth. To integrate these observations, subsequent forward Finite Element models will quantify the importance of rheology and</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.3766M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.3766M"><span id="translatedtitle">Modern Tectonic <span class="hlt">Deformation</span> in the <span class="hlt">Active</span> Basin-and-Range Province Northwest of Beijing, China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mi, Suting; Wen, Xueze</p> <p>2013-04-01</p> <p>Our study region is the northwest of Beijing, northern north China. The most typical extensional <span class="hlt">active</span> tectonic area of the China continent, called the <span class="hlt">active</span> basin-and-range province northwest of Beijing, exist there. This <span class="hlt">active</span> tectonic province is made up of several NE-trending Quaternary graben basins and horst ranges between basins. An about 1500-year-long written historical record has suggested that there have been no major earthquakes with magnitude 7 or greater occurred in most of the study region since AD 512. So, the characteristic of modern tectonic <span class="hlt">deformation</span> of the study region and its implication for the future seismic potential of major earthquakes are important scientific issues. In this study, based on data of regional GPS station velocities and <span class="hlt">active</span> tectonics, combining relocated earthquake distribution, we make a preliminary analysis on the characteristic of the modern tectonic <span class="hlt">deformation</span> of the study region. We design three zones across deferent segments of the <span class="hlt">active</span> basin-and-range province to analyze both the present tectonic <span class="hlt">deformation</span> from the GPS velocity profiles and the major fault's downward-extents from the relocated hypocenters. Our analyses reveal that: (1) Significant NNW-ward and SSE-ward horizontal extension exists on different segments of the <span class="hlt">active</span> basin-and-range province northwest of Beijing at rates of 2 to 3mm /yr, accompanied with right-lateral shear <span class="hlt">deformation</span> at 1 to 2mm/yr. (2) On the western and middle segments of the <span class="hlt">active</span> basin and range province, most of the total horizontal extension and shear <span class="hlt">deformation</span> happen in the width from the Huangqihai basin to the Datong-Yanggao basin , suggesting that some major faults in this width could have had relatively-high strain build-up. (3) It is possible that one or more basement detachment belts exist under the <span class="hlt">active</span> basins, and it or they possibly dip(s) southeastern-ward. (4) The modern tectonic extensional rate is up to 2 to 3mm /yr in the study region. However</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EJPh...33..551R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EJPh...33..551R"><span id="translatedtitle">Testing plastic <span class="hlt">deformations</span> of materials in the introductory undergraduate <span class="hlt">mechanics</span> laboratory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Romo-Kröger, C. M.</p> <p>2012-05-01</p> <p>Normally, a <span class="hlt">mechanics</span> laboratory at the undergraduate level includes an experiment to verify compliance with Hooke's law in materials, such as a steel spring and an elastic rubber band. Stress-strain curves are found for these elements. Compression in elastic bands is practically impossible to achieve due to flaccidity. A typical experiment for the complete loading-unloading cycle is to subject a tubular object to torsion. This paper suggests simple experiments for studying properties concerning elasticity and plasticity in elements of common use, subjected to stretching or compression, and also torsion reinforcing. The experiments use plastic binders, rubber bands and metal springs under a moderate load. This paper discusses an experiment with an original device to measure torsion <span class="hlt">deformations</span> as a function of applied torques, which permitted construction of the hysteresis cycle for a rubber hose and various tubes. Another experiment was designed to define the temporal recovery of a plastic spring with initial stretching. A simple mathematical model was developed to explain this phenomenon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009MMTA...40..342H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009MMTA...40..342H"><span id="translatedtitle">Cyclic <span class="hlt">Deformation</span> of Advanced High-Strength Steels: <span class="hlt">Mechanical</span> Behavior and Microstructural Analysis</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hilditch, Timothy B.; Timokhina, Ilana B.; Robertson, Leigh T.; Pereloma, Elena V.; Hodgson, Peter D.</p> <p>2009-02-01</p> <p>The fatigue properties of multiphase steels are an important consideration in the automotive industry. The different microstructural phases present in these steels can influence the strain life and cyclic stabilized strength of the material due to the way in which these phases accommodate the applied cyclic strain. Fully reversed strain-controlled low-cycle fatigue tests have been used to determine the <span class="hlt">mechanical</span> fatigue performance of a dual-phase (DP) 590 and transformation-induced plasticity (TRIP) 780 steel, with transmission electron microscopy (TEM) used to examine the <span class="hlt">deformed</span> microstructures. It is shown that the higher strain life and cyclic stabilized strength of the TRIP steel can be attributed to an increased yield strength. Despite the presence of significant levels of retained austenite in the TRIP steel, both steels exhibited similar cyclic softening behavior at a range of strain amplitudes due to comparable ferrite volume fractions and yielding characteristics. Both steels formed low-energy dislocation structures in the ferrite during cyclic straining.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/866125','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/866125"><span id="translatedtitle">Metastable alloy materials produced by solid state reaction of compacted, <span class="hlt">mechanically</span> <span class="hlt">deformed</span> mixtures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Atzmon, Michael; Johnson, William L.; Verhoeven, John D.</p> <p>1987-01-01</p> <p>Bulk metastable, amorphous or fine crystalline alloy materials are produced by reacting cold-worked, <span class="hlt">mechanically</span> <span class="hlt">deformed</span> filamentary precursors such as metal powder mixtures or intercalated metal foils. Cold-working consolidates the metals, increases the interfacial area, lowers the free energy for reaction, and reduces at least one characteristic dimension of the metals. For example, the grains (13) of powder or the sheets of foil are clad in a container (14) to form a disc (10). The disc (10) is cold-rolled between the nip (16) of rollers (18,20) to form a flattened disc (22). The grains (13) are further elongated by further rolling to form a very thin sheet (26) of a lamellar filamentary structure (FIG. 4) containing filaments having a thickness of less than 0.01 microns. Thus, diffusion distance and time for reaction are substantially reduced when the flattened foil (28) is thermally treated in oven (32) to form a composite sheet (33) containing metastable material (34) dispersed in unreacted polycrystalline material (36).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24583783','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24583783"><span id="translatedtitle">Effect of the compaction platform on the densification parameters of tableting excipients with different <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Rojas, John; Hernandez, Santiago</p> <p>2014-01-01</p> <p>Several compaction models have been attempted to explain the compression and compaction phenomena of excipients. However, the resulting parameters could be influenced by the compaction platform such as dwell time, compact mass, geometry and type of material. The goal of this study is to assess the effect of these variables on the densification parameters obtained from key models such as Heckel, non-linear Heckel, Kawakita, Carstensen, and Leuenberger. The relationship among the parameters derived was determined by employing a Principal Component Analysis. Results indicated that factors such as compact geometry, consolidation time and compact mass had a negligible impact on parameters such as tensile strength, yield pressure and compressibility. On the contrary, the excipient type had the largest influence on these parameters. Further, the Leuenberger (γ) and Carstensen (f) parameters were highly correlated and related to the excipient <span class="hlt">deformation</span> <span class="hlt">mechanism</span>. Sorbitol and PVP-k30 were the most highly compactable excipients and were characterized for having a low yield pressure (P(y)), compressibility (a), and critical porosity (ε(c)). The magnitude of these parameters was highly dependent on the consolidation behavior of each material. PMID:24583783</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25713457','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25713457"><span id="translatedtitle">Microstructural <span class="hlt">mechanisms</span> of cyclic <span class="hlt">deformation</span>, fatigue crack initiation and early crack growth.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mughrabi, Haël</p> <p>2015-03-28</p> <p>In this survey, the origin of fatigue crack initiation and damage evolution in different metallic materials is discussed with emphasis on the responsible microstructural <span class="hlt">mechanisms</span>. After a historical introduction, the stages of cyclic <span class="hlt">deformation</span> which precede the onset of fatigue damage are reviewed. Different types of cyclic slip irreversibilities in the bulk that eventually lead to the initiation of fatigue cracks are discussed. Examples of trans- and intercrystalline fatigue damage evolution in the low cycle, high cycle and ultrahigh cycle fatigue regimes in mono- and polycrystalline face-centred cubic and body-centred cubic metals and alloys and in different engineering materials are presented, and some microstructural models of fatigue crack initiation and early crack growth are discussed. The basic difficulties in defining the transition from the initiation to the growth of fatigue cracks are emphasized. In ultrahigh cycle fatigue at very low loading amplitudes, the initiation of fatigue cracks generally occupies a major fraction of fatigue life and is hence life controlling. PMID:25713457</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARG42002G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARG42002G"><span id="translatedtitle">How <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> of Polymers during Vitrification Alters the Subsequent Stability of the Glass</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gray, Laura A. G.; Roth, Connie B.</p> <p>2015-03-01</p> <p>How stress and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> impart mobility to polymer glasses have been studied primarily for materials where the glassy state was formed stress free. Here, we investigate the stability of polymer glasses where a constant stress is applied during the formation of the glassy state (thermal quench). Previously we found that physical aging is strongly dependent on the conditions during glass formation, including cooling rate and (often unintended) stress [Macromolecules 2012, 45, 1701]. We constructed a unique jig to apply a known stress to free-standing films during the thermal quench. We used ellipsometry to measure the physical aging rate of polystyrene films by quantifying the time-dependent decrease in film thickness that results from an increase in average film density during aging. As the magnitude of stress during vitrification increases, the physical aging rate quickly transitions over a small range of stresses to a faster aging rate, indicating the resulting glass is less stable [Soft Matter 2014, 10, 1572]. To explore this unique finding, we have constructed a computer-controlled apparatus to measure and apply stress and strain to polymer films during vitrification in order to characterize the temperature-dependent stress build up.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JSG....89..144B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JSG....89..144B&link_type=ABSTRACT"><span id="translatedtitle">Dolomite microstructures between 390° and 700 °C: Indications for <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and grain size evolution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berger, Alfons; Ebert, Andreas; Ramseyer, Karl; Gnos, Edwin; Decrouez, Danielle</p> <p>2016-08-01</p> <p>Dolomitic marble on the island of Naxos was <span class="hlt">deformed</span> at variable temperatures ranging from 390 °C to >700 °C. Microstructural investigations indicate two end-member of <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>: (1) Diffusion creep processes associated with small grain sizes and weak or no CPO (crystallographic preferred orientation), whereas (2) dislocation creep processes are related with larger grain sizes and strong CPO. The change between these <span class="hlt">mechanisms</span> depends on grain size and temperature. Therefore, sample with dislocation and diffusion creep microstructures and CPO occur at intermediate temperatures in relative pure dolomite samples. The measured dolomite grain size ranges from 3 to 940 μm. Grain sizes at Tmax >450 °C show an Arrhenius type evolution reflecting the stabilized grain size in <span class="hlt">deformed</span> and relative pure dolomite. The stabilized grain size is five times smaller than that of calcite at the same temperature and shows the same Arrhenius-type evolution. In addition, the effect of second phase particle influences the grain size evolution, comparable with calcite. Calcite/dolomite mixtures are also characterized by the same difference in grain size, but recrystallization <span class="hlt">mechanism</span> including chemical recrystallization induced by <span class="hlt">deformation</span> may contribute to apparent non-temperature equilibrated Mg-content in calcite.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SMaS...25h5047M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SMaS...25h5047M&link_type=ABSTRACT"><span id="translatedtitle">Simulation and experimental investigation of <span class="hlt">active</span> lightweight compliant <span class="hlt">mechanisms</span> with integrated piezoceramic actuators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Modler, Niels; Winkler, Anja; Filippatos, Angelos; Lovasz, Erwin-Christian; Mărgineanu, Dan</p> <p>2016-08-01</p> <p>Compliant <span class="hlt">mechanisms</span> with integrated actuators can enable new function-integrative structures through the elastic <span class="hlt">deformation</span> of elements without the use of classical links and joints. For such designs, the <span class="hlt">mechanical</span> behaviour of the <span class="hlt">mechanism</span> has to be well known, because external loads, the utilised materials and the geometry of the structural parts influence the <span class="hlt">deformation</span> performance significantly. In order to speed up the development process of such <span class="hlt">mechanisms</span>, a tool for the dynamic analysis of compliant movements is necessary before any further FEM simulation and manufacturing. Therefore, the paper presents a simulating procedure for <span class="hlt">active</span> compliant <span class="hlt">mechanisms</span> obtained through the integration of piezoceramic actuators into fibre-reinforced composite structures using a double layer model. A new <span class="hlt">mechanism</span> was designed, simulated, constructed and tested. The comparison between simulation and experimental results confirm the effectiveness of the presented procedure in regard to the design phase of new <span class="hlt">active</span> compliant structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Tectp.655...41M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Tectp.655...41M"><span id="translatedtitle"><span class="hlt">Mechanics</span>, microstructure and AMS evolution of a synthetic porphyritic calcite aggregate <span class="hlt">deformed</span> in torsion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marques, F. O.; Machek, M.; Roxerová, Z.; Burg, J.-P.; Almqvist, B. S. G.</p> <p>2015-08-01</p> <p>In order to investigate the <span class="hlt">mechanical</span>, microstructural and AMS evolution of porphyritic mylonites, we made a synthetic aggregate composed of 70% fine calcite (< 50 μm) and 30% coarse calcite (200-700 μm), and <span class="hlt">deformed</span> cylindrical specimens in torsion at 300 MPa, 727 °C, a constant strain rate of 3.0E- 4 s- 1, to shear strains γ ≈ 1 and 5. After peak stress, dynamic recrystallization of porphyroclasts resulted in grain size reduction and weakening till a <span class="hlt">mechanical</span> steady state was reached. Microstructural, AMS and EBSD analyses show the consistent evolution of pre-torsion (cold-pressed) planar fabric from perpendicular to sample cylinder axis at γ ≈ 0, to oblique at γ ≈ 1, and finally to low angle to the shear plane at γ ≈ 5, as expected for approximate simple shear. At γ ≈ 1, stretched calcite grains > 3 mm in length defined a conspicuous foliation, and showed aligned twins. At γ ≈ 5, calcite porphyroclasts were highly stretched (aspect ratio around 20), and had rotated towards the shear plane. Between γ = 1 and 5, a composite fabric formed, one at low and the other at high angle to the shear plane, from which shear sense can be deduced. The AMS patterns were sensitive to increasing shearing, and tracked strain reasonably well, despite the reduced size and low susceptibility of specimens. From the CPO and the microstructure, we infer that a balance compatible with an optimal dissipation of the applied stress was achieved between grain growth and grain reduction processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4351114','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4351114"><span id="translatedtitle">Mechanotransduction <span class="hlt">Mechanisms</span> for Intraventricular Diastolic Vortex Forces and Myocardial <span class="hlt">Deformations</span>: Part 1</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Pasipoularides, Ares</p> <p>2015-01-01</p> <p>Epigenetic <span class="hlt">mechanisms</span> are fundamental in cardiac adaptations, remodeling, reverse remodeling, and disease. This 2-article series proposes that variable forces associated with diastolic RV/LV rotatory intraventricular flows can exert physiologically and clinically important, albeit still unappreciated, epigenetic actions influencing functional and morphological cardiac adaptations and/or maladaptations. Taken in-toto, the 2-part survey formulates a new paradigm in which intraventricular diastolic filling vortex-associated forces play a fundamental epigenetic role, and examines how heart cells react to these forces. The objective is to provide a perspective on vortical epigenetic effects, to introduce emerging ideas and suggest directions of multidisciplinary translational research. The main goal is to make pertinent biophysics and cytomechanical dynamic systems concepts accessible to interested translational and clinical cardiologists. I recognize that the diversity of the epigenetic problems can give rise to a diversity of approaches and multifaceted specialized research undertakings. Specificity may dominate the picture. However, I take a contrasting approach. Are there concepts that are central enough that they should be developed in some detail? Broadness competes with specificity. Would however this viewpoint allow for a more encompassing view that may otherwise be lost by generation of fragmented results? Part 1 serves as a general introduction, focusing on background concepts, on intracardiac vortex imaging methods, and on diastolic filling vortex-associated forces acting epigenetically on RV/LV endocardium and myocardium. Part 2 will describe pertinent available pluridisciplinary knowledge/research relating to mechanotransduction <span class="hlt">mechanisms</span> for intraventricular diastolic vortex forces and myocardial <span class="hlt">deformations</span> and to their epigenetic actions on myocardial and ventricular function and adaptations. PMID:25624114</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=160725','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=160725"><span id="translatedtitle">Root Hair <span class="hlt">Deformation</span> <span class="hlt">Activity</span> of Nodulation Factors and Their Fate on Vicia sativa.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Heidstra, R.; Geurts, R.; Franssen, H.; Spaink, H. P.; Van Kammen, A.; Bisseling, T.</p> <p>1994-01-01</p> <p>We used a semiquantitative root hair <span class="hlt">deformation</span> assay for Vicia sativa (vetch) to study the <span class="hlt">activity</span> of Rhizobium leguminosarum bv viciae nodulation (Nod) factors. Five to 10 min of Nod factor-root interaction appears to be sufficient to induce root hair <span class="hlt">deformation</span>. The first <span class="hlt">deformation</span> is visible within 1 h, and after 3 h about 80% of the root hairs in a small susceptible zone of the root are <span class="hlt">deformed</span>. This zone encompasses root hairs that have almost reached their maximal size. The Nod factor accumulates preferentially to epidermal cells of the young part of the root, but is not restricted to the susceptible zone. In the interaction with roots, the glucosamine backbone of Nod factors is shortened, presumably by chitinases. NodRlv-IV(C18:4,Ac) is more stable than NodRlv-V(C18:4,Ac). No correlation was found between Nod factor degradation and susceptibility. Degradation occurs both in the susceptible zone and in the mature zone. Moreover, degradation is not affected by NH4NO3 and is similar in vetch and in the nonhost alfalfa (Medicago sativa). PMID:12232242</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007PMM...104..408C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007PMM...104..408C"><span id="translatedtitle">Phase transformations during <span class="hlt">deformation</span> of Fe-Ni and Fe-Mn alloys produced by <span class="hlt">mechanical</span> alloying</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cherdyntsev, V. V.; Pustov, L. Yu.; Kaloshkin, S. D.; Tomilin, I. A.; Shelekhov, E. V.; Laptev, A. I.; Baldokhin, Yu. V.; Estrin, E. I.</p> <p>2007-10-01</p> <p>Compositions of Fe(100 - x)Mn x ( x = 10 and 12 at. %) and Fe(100 - y)Ni y ( y = 18 and 20 at. %) were produced by combined <span class="hlt">mechanical</span> alloying of pure-metal powders and annealed in the austenitic field. After annealing and cooling to room temperature, the alloys had a single-phase austenitic structure. During <span class="hlt">deformation</span>, the γ phase partially transforms into the α 2 phase (and/or ɛ phase in Fe-Mn alloys). The phase composition of the alloys after <span class="hlt">deformation</span> depends on the amount of alloying elements and the predeformation annealing regime. The amount of martensite in the structure of a bulk alloy obtained by powder compacting grows proportionally to the degree of <span class="hlt">deformation</span> of the sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SPIE.9602E..0BA','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SPIE.9602E..0BA"><span id="translatedtitle">Correction of an <span class="hlt">active</span> space telescope mirror using a gradient approach and an additional <span class="hlt">deformable</span> mirror</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allen, Matthew R.; Kim, Jae Jun; Agrawal, Brij N.</p> <p>2015-09-01</p> <p>High development cost is a challenge for space telescopes and imaging satellites. One of the primary reasons for this high cost is the development of the primary mirror, which must meet diffraction limit surface figure requirements. Recent efforts to develop lower cost, lightweight, replicable primary mirrors include development of silicon carbide actuated hybrid mirrors and carbon fiber mirrors. The silicon carbide actuated hybrid mirrors at the Naval Postgraduate School do not meet the surface quality required for an optical telescope due to high spatial frequency residual surface errors. A technique under investigation at the Naval Postgraduate School is to correct the residual surface figure error using a <span class="hlt">deformable</span> mirror in the optical path. We present a closed loop feedback gradient controller to <span class="hlt">actively</span> control a SMT <span class="hlt">active</span> segment and an additional <span class="hlt">deformable</span> mirror to reduce residual wavefront error. The simulations and experimental results show that the gradient controller reduces the residual wavefront error more than an integral controller.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860053059&hterms=1980+Mexico&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D1980%2BMexico','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860053059&hterms=1980+Mexico&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3D1980%2BMexico"><span id="translatedtitle">Evidence of ongoing crustal <span class="hlt">deformation</span> related to magmatic <span class="hlt">activity</span> near Socorro, New Mexico</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Larsen, S.; Brown, L.; Reilinger, R.</p> <p>1986-01-01</p> <p>Leveling measurements conducted in 1980-1981 by the National Geodetic Survey in the Socorro area of the Rio Grande rift are analyzed. Crustal uplift related to magma inflation in the midcrustal magma body is detected; an uplift of 0.18 cm/yr is measured for the time between 1951-1980. The survey data of 1911 and 1959 are compared to the present data and good correlation is observed. The systematic leveling errors including height-dependence and refraction errors are studied. The 30-km-wide subsidence in the area is examined. The spatial correlation between seismic <span class="hlt">activity</span>, the Socorro magma body, and crustal <span class="hlt">deformation</span> in Socorro is investigated. The crustal movement from magma reservior <span class="hlt">activities</span> is modeled using the formulations of Dieterich and Decker (1975). The modeling of the <span class="hlt">deformation</span> reveals that the movement in the Socorro area is associated with the 19-km deep Socorro magma body.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EPJWC..4104005V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EPJWC..4104005V"><span id="translatedtitle">Competition between inverse piezoelectric effect and <span class="hlt">deformation</span> potential <span class="hlt">mechanism</span> in undoped GaAs revealed by ultrafast acoustics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vaudel, G.; Ruello, P.; Pezeril, T.; Gusev, V.</p> <p>2013-03-01</p> <p>By using the picosecond ultrasonics technique, piezoelectric effect in <111> GaAs undoped sample at both faces (A[111] and B[-1-1-1]) is experimentally studied. We demonstrate that piezoelectric generation of sound can dominate in <111> GaAs material over the <span class="hlt">deformation</span> potential <span class="hlt">mechanism</span> even in the absence of static externally applied or built-in electric field in the semiconductor material. In that case, the Dember field, caused by the separation of photo-generated electrons and holes in the process of supersonic diffusion, is sufficient for the dominance of the piezoelectric <span class="hlt">mechanism</span> during the optoacoustic excitation. The experimental results on the sample at both faces reveal that in one case (A face), the two <span class="hlt">mechanisms</span>, piezoelectric effect and <span class="hlt">deformation</span> potential, can compensate each other leading to a large decrease of the measured Brillouin oscillation magnitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5542353','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5542353"><span id="translatedtitle">Present-day crustal movements and the <span class="hlt">mechanics</span> of cyclic <span class="hlt">deformation</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Thatcher, W.</p> <p>1990-01-01</p> <p>Contemporary crustal movements in California are concentrated within a plate-boundary <span class="hlt">deformation</span> zone that is typically 50 to 200 km wide, centered approximately on the San Andreas fault. Observations of coseismic, postseismic, and interseismic movements define the earthquake <span class="hlt">deformation</span> cycle and constrain models of strain accumulation and release for strike-slip plate boundaries. This chapter describes shear strain on the San Andreas fault system; aseismic slip, integrated displacement rates, and Pacific-North American plate motion; detailed displacement-rate patterns; and thick- and thin-lithosphere models and stress-slip-constitutive-law fault models of <span class="hlt">deformation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.8170R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014EGUGA..16.8170R&link_type=ABSTRACT"><span id="translatedtitle">The <span class="hlt">Mechanics</span> and Energetics of Soil Bioturbation by Plant Roots and Earthworms - Plastic <span class="hlt">Deformation</span> Considerations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruiz, Siul; Or, Dani; Schymanski, Stanislaus</p> <p>2014-05-01</p> <p>Soil structure plays a critical factor in the agricultural, hydrological and ecological functions of soils. These services are adversely impacted by soil compaction, a damage that could last for many years until functional structure is restored. An important class of soil structural restoration processes are related to biomechanical <span class="hlt">activity</span> associated with burrowing of earthworms and root proliferation in impacted soil volumes. We study details of the <span class="hlt">mechanical</span> processes and energetics associated with quantifying the rates and <span class="hlt">mechanical</span> energy required for soil structural restoration. We first consider plastic cavity expansion to describe earthworm and plant root radial expansion under various conditions. We then use cone penetration models as analogues to wedging induced by root tip growth and worm locomotion. The associated <span class="hlt">mechanical</span> stresses and strains determine the <span class="hlt">mechanical</span> energy associated with bioturbation for different hydration conditions and root/earthworm geometries. Results illustrate a reduction in strain energy with increasing water content and trade-offs between pressure and energy investment for various root and earthworm geometries. The study provides the basic building blocks for estimating rates of soil structural alteration, the associated energetic requirements (soil carbon, plant assimilates) needed to sustain structure regeneration by earthworms and roots, and highlights potential <span class="hlt">mechanical</span> cut-offs for such <span class="hlt">activities</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMEP...24.3746D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMEP...24.3746D"><span id="translatedtitle">High Temperature <span class="hlt">Mechanical</span> Behavior of Ti-45Al-8Nb and Its Cavity Evolution in <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, Zhihao; Zhang, Kaifeng; Jiang, Shaosong; Zhu, Ruican; Li, Shuguang</p> <p>2015-10-01</p> <p>The tensile property of a high Nb containing TiAl-based alloy (Ti-45Al-8Nb) was investigated in the temperature range of 900-1050 °C and strain rate range of 1 × 10-3 to 2.5 × 10-2 s-1. The results revealed that the yield stress decreased with increasing temperature and decreasing strain rate, while the tensile elongation increased with an increase in temperature and a decrease in strain rate. Hence, The minimum yield stress of 119.2 MPa and the maximum elongation of 237% were obtained at the temperature of 1050 °C and strain rate of 1 × 10-3 s-1. Based on the experimental data, the <span class="hlt">activation</span> energy of the alloy was calculated to be 360 kJ/mol. Moreover, the microstructure and the fracture morphology of the specimens were observed, and the results revealed that the distribution of cavities was related to <span class="hlt">deformation</span> parameters and the fracture mode was typically dimple-type.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014apra.prop..105S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014apra.prop..105S&link_type=ABSTRACT"><span id="translatedtitle">A High-Performance <span class="hlt">Deformable</span> Mirror with Integrated Driver ASIC for Space Based <span class="hlt">Active</span> Optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shelton, Chris</p> <p></p> <p>Direct imaging of exoplanets is key to fully understanding these systems through spectroscopy and astrometry. The primary impediment to direct imaging of exoplanets is the extremely high brightness ratio between the planet and its parent star. Direct imaging requires a technique for contrast suppression, which include coronagraphs, and nulling interferometers. <span class="hlt">Deformable</span> mirrors (DMs) are essential to both of these techniques. With space missions in mind, Microscale is developing a novel DM with direct integration of DM and its electronic control functions in a single small envelope. The Application Specific Integrated Circuit (ASIC) is key to the shrinking of the electronic control functions to a size compatible with direct integration with the DM. Through a NASA SBIR project, Microscale, with JPL oversight, has successfully demonstrated a unique <span class="hlt">deformable</span> mirror (DM) driver ASIC prototype based on an ultra-low power switch architecture. Microscale calls this the Switch-Mode ASIC, or SM-ASIC, and has characterized it for a key set of performance parameters, and has tested its operation with a variety of actuator loads, such as piezo stack and unimorph, and over a wide temperature range. These tests show the SM-ASIC's capability of supporting <span class="hlt">active</span> optics in correcting aberrations of a telescope in space. Microscale has also developed DMs to go with the SM-ASIC driver. The latest DM version produced uses small piezo stack elements in an 8x8 array, bonded to a novel silicon facesheet structure fabricated monolithically into a polished mirror on one side and <span class="hlt">mechanical</span> linkage posts that connect to the piezoelectric stack actuators on the other. In this Supporting Technology proposal we propose to further develop the ASIC-DM and have assembled a very capable team to do so. It will be led by JPL, which has considerable expertise with DMs used in Adaptive Optics systems, with high-contrast imaging systems for exoplanet missions, and with designing DM driver</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999JSV...224..489C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999JSV...224..489C&link_type=ABSTRACT"><span id="translatedtitle">Effects of Structural <span class="hlt">Deformations</span> of the Crank-Slider <span class="hlt">Mechanism</span> on the Estimation of the Instantaneous Engine Friction Torque</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>CHALHOUB, N. G.; NEHME, H.; HENEIN, N. A.; BRYZIK, W.</p> <p>1999-07-01</p> <p>The focus on the current study is to assess the effects of structural <span class="hlt">deformations</span> of the crankshaft/connecting-rod/piston <span class="hlt">mechanism</span> on the computation of the instantaneous engine friction torque. This study is performed in a fully controlled environment in order to isolate the effects of structural <span class="hlt">deformations</span> from those of measurement errors or noise interference. Therefore, a detailed model, accounting for the rigid and flexible motions of the crank-slider <span class="hlt">mechanism</span> and including engine component friction formulations, is considered in this study. The model is used as a test bed to generate the engine friction torque,Tfa, and to predict the rigid and flexible motions of the system in response to the cylinder gas pressure. The torsional vibrations and the rigid body angular velocity of the crankshaft, as predicted by the detailed model of the crank-slider <span class="hlt">mechanism</span>, are used along with the engine load torque and the cylinder gas pressure in the (P-ω) method to estimate the engine friction torque,Tfe. This method is well suited for the purpose of this study because its formulation is based on the rigid body model of the crank-slider <span class="hlt">mechanism</span>. The digital simulation results demonstrate that the exclusion of the structural <span class="hlt">deformations</span> of the crank-slider <span class="hlt">mechanism</span> from the formulation of the (P-ω) method leads to an overestimation of the engine friction torque near the top-dead-center (TDC) position of the piston under firing conditions. Moreover, for the remainder of the engine cycle, the estimated friction torque exhibits large oscillations and takes on positive numerical values as if it is inducing energy into the system. Thus, the adverse effects of structural <span class="hlt">deformations</span> of the crank-slider <span class="hlt">mechanism</span> on the estimation of the engine friction torque greatly differ in their nature from one phase of the engine cycle to another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001LPI....32.1560K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001LPI....32.1560K"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> During Impact Crater Modification Inferred from the Crooked Creek Impact Structure, Missouri, USA</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kenkmann, T.</p> <p>2001-03-01</p> <p>Microstructural investigations show that intergranular fracturing and brittle shear zone formation are dominant <span class="hlt">deformation</span> modes during crater modification. Indications for plastic flow and granular flow were not found on the scale of observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26511269','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26511269"><span id="translatedtitle">The influence of metallic shell <span class="hlt">deformation</span> on the contact <span class="hlt">mechanics</span> of a ceramic-on-ceramic total hip arthroplasty.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Qiu, Changdong; Wang, Ling; Li, Dichen; Jin, Zhongmin</p> <p>2016-01-01</p> <p>Total hip arthroplasty of ceramic-on-ceramic bearing combinations is increasingly used clinically. The majority of these implants are used with cementless fixation that a metal-backing shell is press-fitted into the pelvic bone. This usually results in the <span class="hlt">deformation</span> of the metallic shell, which may also influence the ceramic liner <span class="hlt">deformation</span> and consequently the contact <span class="hlt">mechanics</span> between the liner and the femoral head under loading. The explicit dynamic finite element method was applied to model the implantation of a cementless ceramic-on-ceramic with a titanium shell and subsequently to investigate the effect of the metallic shell <span class="hlt">deformation</span> on the contact <span class="hlt">mechanics</span>. A total of three impacts were found to be necessary to seat the titanium alloy shell into the pelvic bone cavity with a 1 mm diameter interference and a 1.3 kg impactor at 4500 mm s(-1) velocity. The maximum <span class="hlt">deformation</span> of the metallic shell was found to be 160 µm in the antero-superior and postero-inferior direction and 97 µm in the antero-inferior and postero-superior direction after the press-fit. The corresponding values were slightly reduced to 67 and 45 µm after the ceramic liner was inserted and then modified to 74 and 43 µm under loading, respectively. The maximum <span class="hlt">deformation</span> and the maximum principal stress of the ceramic liner were 31 µm and 144 MPa (tensile stress), respectively, after it was inserted into the shell and further increased to 52 µm and 245 MPa under loading. This research highlights the importance of the press-fit of the metallic shell on the contact <span class="hlt">mechanics</span> of the ceramic liner for ceramic-on-ceramic total hip arthroplasties and potential clinical performances. PMID:26511269</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870005708','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870005708"><span id="translatedtitle">Structural ensembles of the north belt of Venus <span class="hlt">deformations</span> and possible <span class="hlt">mechanisms</span> of their formation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Markov, M. S.</p> <p>1986-01-01</p> <p>The author discusses structural formations in the northern <span class="hlt">deformation</span> belt of Venus, studied according to the data of the radar pictures obtained with the Venera 15 and 16 probes. He shows that it consists of regions of compression with submeridional orientation, regions of displacement, extending in the sublatitudinal direction and individual slightly <span class="hlt">deformed</span> blocks. He puts forward the hypothesis that the formation of these structures is related with horizontal movements in the mantle in the sublatitudinal direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T41A2100H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T41A2100H"><span id="translatedtitle">Implications of Microstructural Studies of the SAFOD Gouge for the Strength and <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in the Creeping Segment of the San Andreas Fault</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hadizadeh, J.; Gratier, J. L.; Mittempergher, S.; Renard, F.; Richard, J.; di Toro, G.; Babaie, H. A.</p> <p>2010-12-01</p> <p>The San Andreas Fault zone (SAF) in the vicinity of the San Andreas Fault Observatory at Depth (SAFOD)in central California is characterized by an average 21 mm/year aseismic creep and strain release through repeating M<3 earthquakes. Seismic inversion studies indicate that the ruptures occur on clusters of stationary patches making up 1% or less of the total fault surface area. The existence of these so-called asperity patches, although not critical in determining the fault strength, suggests interaction of different <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>. What are the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span>, and how do the <span class="hlt">mechanisms</span> couple and factor into the current strength models for the SAF? The SAFOD provides core samples and geophysical data including cores from two shear zones where the main borehole casing is <span class="hlt">deforming</span>. The studies so far show a weak fault zone with about 200m of low-permeability damage zone without anomalous temperature or high fluid pressure (Zoback et al. EOS 2010). To answer the above questions, we studied core samples and thin sections ranging in measured depths (MD) from 3059m to 3991m including gouge from borehole casing <span class="hlt">deformation</span> zones. The methods of study included high resolution scanning and transmission electron microscopy, cathodoluminescence imaging, X-ray fluorescence mapping, and energy dispersive X-ray spectroscopy. The microstructural and analytical data suggest that <span class="hlt">deformation</span> is by a coupling of cataclastic flow and pressure solution accompanied by widespread alteration of feldspar to clay minerals and other neomineralizations. The clay contents of the gouge and streaks of serpentinite are not uniformly distributed, but weakness of the creeping segment is likely to be due to intrinsically low frictional strength of the fault material. This conclusion, which is based on the overall ratio of clay/non-clay constituents and the presence of talc in the <span class="hlt">actively</span> <span class="hlt">deforming</span> zones, is consistent with the 0.3-0.45 coefficient of friction for the drill</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.G31A0934C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.G31A0934C"><span id="translatedtitle">Crustal-scale <span class="hlt">active</span> <span class="hlt">deformation</span> along the Ecuadorian Andes using Persistent Scatterers SAR Interferometry</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Champenois, J.; Baize, S.; Audin, L.; Pinel, V.; Alvarado, A.; Jomard, H.; Yepes, H. A.</p> <p>2013-12-01</p> <p>Located in the Northern Andes along the <span class="hlt">active</span> subduction zone of the Nazca plate beneath the South American continent, Ecuador is highly exposed to seismic hazard. For the last ten years, numerous multidisciplinary studies focused on major seismicity related to the subduction, whereas few investigations concentrated on M>7 crustal seismicity in the upper plate (like 1797 Riobamba earthquake, ML 8.3, 12.000 deaths). The <span class="hlt">active</span> faults producing these earthquakes are poorly known in term of slip rate and for some cases are even not identified yet. Additionnally, Ecuador is one of the most <span class="hlt">active</span> volcanic areas of the northern Andean volcanic zone. Three among the nine <span class="hlt">active</span> volcanoes are actually erupting (Reventador, Tungurahua, and Sangay). For the last 5 years, geodetic networks have been deployed in Ecuador to enhance crustal <span class="hlt">deformation</span> monitoring, but these point-wise techniques cannot provide spatially dense maps of ground <span class="hlt">deformation</span> and are quite expensive methods. To address this issue, we applied the Persistent Scatterers SAR Interferometry technique (StaMPS/MTI freeware developed by A. Hooper) to ENVISAT SAR data between 2003 and 2009. Using these cost-effective techniques, we are able to investigate both tectonic and volcanic surface <span class="hlt">deformations</span> with an unprecedented spatial density of measurements. This study presents new PS-InSAR results along the Ecuadorian Andes, close to the area of Riobamba. We generated average velocity maps and consistent time-series of displacements measured along the radar line of sight. These results evidence large scale <span class="hlt">deformation</span> localized on the Pallatanga fault system (locked fault) compatible with a model of locked strike slip fault. Moreover, these results show an important growth of the Tungurahua volcanic complex (maximum rate about 9 mm/yr) with a rapid uplift prior and post 2006 explosive eruption. We investigate the time-series of displacement for 22 images. Our results permitted to propose two crustal source</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118363','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4118363"><span id="translatedtitle">Arterial <span class="hlt">Mechanical</span> Motion Estimation Based on a Semi-Rigid Body <span class="hlt">Deformation</span> Approach</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Guzman, Pablo; Hamarneh, Ghassan; Ros, Rafael; Ros, Eduardo</p> <p>2014-01-01</p> <p>Arterial motion estimation in ultrasound (US) sequences is a hard task due to noise and discontinuities in the signal derived from US artifacts. Characterizing the <span class="hlt">mechanical</span> properties of the artery is a promising novel imaging technique to diagnose various cardiovascular pathologies and a new way of obtaining relevant clinical information, such as determining the absence of dicrotic peak, estimating the Augmentation Index (AIx), the arterial pressure or the arterial stiffness. One of the advantages of using US imaging is the non-invasive nature of the technique unlike Intra Vascular Ultra Sound (IVUS) or angiography invasive techniques, plus the relative low cost of the US units. In this paper, we propose a semi rigid <span class="hlt">deformable</span> method based on Soft Bodies dynamics realized by a hybrid motion approach based on cross-correlation and optical flow methods to quantify the elasticity of the artery. We evaluate and compare different techniques (for instance optical flow methods) on which our approach is based. The goal of this comparative study is to identify the best model to be used and the impact of the accuracy of these different stages in the proposed method. To this end, an exhaustive assessment has been conducted in order to decide which model is the most appropriate for registering the variation of the arterial diameter over time. Our experiments involved a total of 1620 evaluations within nine simulated sequences of 84 frames each and the estimation of four error metrics. We conclude that our proposed approach obtains approximately 2.5 times higher accuracy than conventional state-of-the-art techniques. PMID:24871987</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1034706','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1034706"><span id="translatedtitle">High-Strain-Induced <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span> in Block-Graft and Multigraft Copolymers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schlegel, Ralf; Duan, Y. X.; Weidisch, Roland; Holzer, Suzette R; Schneider, Ken R; Stamm, M.; Uhrig, David; Mays, Jimmy; Heinrich, G.; Hadjichristidis, Nikolaos</p> <p>2011-01-01</p> <p>The molecular orientation behavior and structural changes of morphology at high strains for multigraft and block graft copolymers based on polystyrene (PS) and polyisoprene (PI) were investigated during uniaxial monotonic loading via FT-IR and synchrotron SAXS. Results from FT-IR revealed specific orientations of PS and PI segments depending on molecular architecture and on the morphology, while structural investigations revealed a typical decrease in long-range order with increasing strain. This decrease was interpreted as strain-induced dissolution of the glassy blocks in the soft matrix, which is assumed to affect an additional enthalpic contribution (strain-induced mixing of polymer chains) and stronger retracting forces of the network chains during elongation. Our interpretation is supported by FT-IR measurements showing similar orientation of rubbery and glassy segments up to high strains. It also points to highly <span class="hlt">deformable</span> PS domains. By synchrotron SAXS, we observed in the neo-Hookean region an approach of glassy domains, while at higher elongations the intensity of the primary reflection peak was significantly decreasing. The latter clearly verifies the assumption that the glassy chains are pulled out from the domains and are partly mixed in the PI matrix. Results obtained by applying models of rubber elasticity to stressstrain and hysteresis data revealed similar correlations between the softening behavior and molecular and morphological parameters. Further, an influence of the network modality was observed (randomgrafted branches). For sphere formingmultigraft copolymers the domain functionality was found to be less important to achieve improved <span class="hlt">mechanical</span> properties but rather size and distribution of the domains.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/24871987','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/24871987"><span id="translatedtitle">Arterial <span class="hlt">mechanical</span> motion estimation based on a semi-rigid body <span class="hlt">deformation</span> approach.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Guzman, Pablo; Hamarneh, Ghassan; Ros, Rafael; Ros, Eduardo</p> <p>2014-01-01</p> <p>Arterial motion estimation in ultrasound (US) sequences is a hard task due to noise and discontinuities in the signal derived from US artifacts. Characterizing the <span class="hlt">mechanical</span> properties of the artery is a promising novel imaging technique to diagnose various cardiovascular pathologies and a new way of obtaining relevant clinical information, such as determining the absence of dicrotic peak, estimating the Augmentation Index (AIx), the arterial pressure or the arterial stiffness. One of the advantages of using US imaging is the non-invasive nature of the technique unlike Intra Vascular Ultra Sound (IVUS) or angiography invasive techniques, plus the relative low cost of the US units. In this paper, we propose a semi rigid <span class="hlt">deformable</span> method based on Soft Bodies dynamics realized by a hybrid motion approach based on cross-correlation and optical flow methods to quantify the elasticity of the artery. We evaluate and compare different techniques (for instance optical flow methods) on which our approach is based. The goal of this comparative study is to identify the best model to be used and the impact of the accuracy of these different stages in the proposed method. To this end, an exhaustive assessment has been conducted in order to decide which model is the most appropriate for registering the variation of the arterial diameter over time. Our experiments involved a total of 1620 evaluations within nine simulated sequences of 84 frames each and the estimation of four error metrics. We conclude that our proposed approach obtains approximately 2.5 times higher accuracy than conventional state-of-the-art techniques. PMID:24871987</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013PhDT........74M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013PhDT........74M&link_type=ABSTRACT"><span id="translatedtitle">The role of microstructure on <span class="hlt">deformation</span> and damage <span class="hlt">mechanisms</span> in a Nickel-based superalloy at elevated temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maciejewski, Kimberly E.</p> <p></p> <p> introduced by considering the mobility limit in the tangential direction leading to strain incompatibility and failure. This limit is diminished by environmental effects which are introduced as a dynamic embrittlement process that hinders grain boundary mobility due to oxygen diffusion. The concepts described herein indicate that implementation of the cohesive zone model requires the knowledge of the grain boundary external and internal <span class="hlt">deformation</span> fields. The external field is generated by developing and coupling two continuum constitutive models including (i) a microstructure-explicit coarse scale crystal plasticity model with strength provided by tertiary and secondary gamma' precipitates. This scale is appropriate for the representation of the continuum region at the immediate crack tip, and (ii) a macroscopic internal state variable model for the purpose of modeling the response of the far field region located several grains away from the crack path. The hardening contributions of the gamma' precipitates consider dislocation/precipitate interactions in terms of gamma' particles shearing and/or Orowan by-passing <span class="hlt">mechanisms</span>. The material parameters for these models are obtained from results of low cycle fatigue tests which were performed at three temperatures; 650, 704 and 760°C. Furthermore, a series of microstructure controlled experiments were carried out in order to develop and validate the microstructure dependency feature of the continuum constitutive models. The second requirement in the implementation of the cohesive zone model is a grain boundary <span class="hlt">deformation</span> model which has been developed, as described above, on the basis of viscous flow rules of the boundary material. This model is supported by dwell crack growth experiments carried out at the three temperatures mentioned above, in both air and vacuum environments. Results of these tests have identified the frequency range in which the grain boundary cohesive zone model is applicable and also provided data to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/850440','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/850440"><span id="translatedtitle">Analysis of Coupled Multiphase Fluid Flow, Heat Transfer and <span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> at the Yucca Mountain Drift Scale Test</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>J. Rutqvist; C.F. Tsang; Y. Tsang</p> <p>2005-05-17</p> <p>A numerical simulation of coupled multiphase fluid flow, heat transfer, and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> was carried out to study coupled thermal-hydrological-<span class="hlt">mechanical</span> (THM) processes at the Yucca Mountain Drift Scale Test (DST) and for validation of a coupled THM numerical simulator. The ability of the numerical simulator to model relevant coupled THM processes at the DST was evaluated by comparison of numerical results to in situ measurements of temperature, water saturation, displacement, and fracture permeability. Of particular relevance for coupled THM processes are thermally induced rock-mass stress and <span class="hlt">deformations</span>, with associated changes in fracture aperture and fractured rock permeability. Thermally induced rock-mass <span class="hlt">deformation</span> and accompanying changes in fracture permeability were reasonably well predicted using a continuum elastic model, although some individual measurements of displacement and permeability indicate inelastic <span class="hlt">mechanical</span> responses. It is concluded that fracture closure/opening caused by a change in thermally induced normal stress across fractures is an important <span class="hlt">mechanism</span> for changes in intrinsic fracture permeability at the DST, whereas fracture shear dilation appears to be less significant. Observed and predicted maximum permeability changes at the DST are within one order of magnitude. These data are important for bounding model predictions of potential changes in rock-mass permeability at a future repository in Yucca Mountain.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SMaS...23i4004S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014SMaS...23i4004S&link_type=ABSTRACT"><span id="translatedtitle">Numerical simulation and experimental validation of the large <span class="hlt">deformation</span> bending and folding behavior of magneto-<span class="hlt">active</span> elastomer composites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheridan, Robert; Roche, Juan; Lofland, Samuel E.; vonLockette, Paris R.</p> <p>2014-09-01</p> <p>This work seeks to provide a framework for the numerical simulation of magneto-<span class="hlt">active</span> elastomer (MAE) composite structures for use in origami engineering applications. The emerging field of origami engineering employs folding techniques, an array of crease patterns traditionally on a single flat sheet of paper, to produce structures and devices that perform useful engineering operations. Effective means of numerical simulation offer an efficient way to optimize the crease patterns while coupling to the performance and behavior of the <span class="hlt">active</span> material. The MAE materials used herein are comprised of nominally 30% v/v, 325 mesh barium hexafarrite particles embedded in Dow HS II silicone elastomer compound. These particulate composites are cured in a magnetic field to produce magneto-elastic solids with anisotropic magnetization, e.g. they have a preferred magnetic axis parallel to the curing axis. The <span class="hlt">deformed</span> shape and/or blocked force characteristics of these MAEs are examined in three geometries: a monolithic cantilever as well as two- and four-segment composite accordion structures. In the accordion structures, patches of MAE material are bonded to a Gelest OE41 unfilled silicone elastomer substrate. Two methods of simulation, one using the Maxwell stress tensor applied as a traction boundary condition and another employing a minimum energy kinematic (MEK) model, are investigated. Both methods capture actuation due to magnetic torque <span class="hlt">mechanisms</span> that dominate MAE behavior. Comparison with experimental data show good agreement with only a single adjustable parameter, either an effective constant magnetization of the MAE material in the finite element models (at small and moderate <span class="hlt">deformations</span>) or an effective modulus in the minimum energy model. The four-segment finite element model was prone to numerical locking at large <span class="hlt">deformation</span>. The effective magnetization and modulus values required are a fraction of the actual experimentally measured values which suggests a</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.T53D1999I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.T53D1999I"><span id="translatedtitle"><span class="hlt">Active</span> faults in the <span class="hlt">deformation</span> zone off Noto Peninsula, Japan, revealed by high- resolution seismic profiles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Inoue, T.; Okamura, Y.; Murakami, F.; Kimura, H.; Ikehara, K.</p> <p>2008-12-01</p> <p>Recently, a lot of earthquakes occur in Japan. The <span class="hlt">deformation</span> zone which many faults and folds have concentrated exists on the Japan Sea side of Japan. The 2007 Noto Hanto Earthquake (MJMA 6.9) and 2007 Chuetsu-oki Earthquake (MJMA 6.8) were caused by <span class="hlt">activity</span> of parts of faults in this <span class="hlt">deformation</span> zone. The Noto Hanto Earthquake occurred on 25 March, 2007 under the northwestern coast of Noto Peninsula, Ishikawa Prefecture, Japan. This earthquake is located in Quaternary <span class="hlt">deformation</span> zone that is continued from northern margin of Noto Peninsula to southeast direction (Okamura, 2007a). National Institute of Advanced Industrial Science and Technology (AIST) carried out high-resolution seismic survey using Boomer and 12 channels short streamer cable in the northern part off Noto Peninsula, in order to clarify distribution and <span class="hlt">activities</span> of <span class="hlt">active</span> faults in the <span class="hlt">deformation</span> zone. A twelve channels short streamer cable with 2.5 meter channel spacing developed by AIST and private corporation is designed to get high resolution seismic profiles in shallow sea area. The multi-channel system is possible to equip on a small fishing boat, because the data acquisition system is based on PC and the length of the cable is short and easy to handle. Moreover, because the channel spacing is short, this cable is very effective for a high- resolution seismic profiling survey in the shallow sea, and seismic data obtained by multi-channel cable can be improved by velocity analysis and CDP stack. In the northern part off Noto Peninsula, seismic profiles depicting geologic structure up to 100 meters deep under sea floor were obtained. The most remarkable reflection surface recognized in the seismic profiles is erosion surface at the Last Glacial Maximum (LGM). In the western part, sediments about 30 meters (40 msec) thick cover the erosional surface that is distributed under the shelf shallower than 100m in depth and the sediments thin toward offshore and east. Flexures like <span class="hlt">deformation</span> in</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JAESc.114..623S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JAESc.114..623S"><span id="translatedtitle">Numerical investigation of the geodynamic <span class="hlt">mechanism</span> for the late Jurassic <span class="hlt">deformation</span> of the Ordos block and surrounding orogenic belts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Yujun; Dong, Shuwen; Zhang, Huai; Shi, Yaolin</p> <p>2015-12-01</p> <p>Orogenic belts have developed along the edges of the stable Ordos block, in northern China. Three main geodynamic models have been proposed to explain the formation of these orogenic belts. They have included the collision between the North China and South China blocks, subduction of the Pacific plate, and stresses transmitted over long distances from the closure of the Mongolia-Okhotsk ocean. However, these explanations are still controversial and not universally accepted, leaving the <span class="hlt">mechanisms</span> that formed the orogenic belts poorly understood. To address these fundamental questions, we developed a 3D numerical model using the finite element method to explore the geodynamic <span class="hlt">mechanism</span> for the late Jurassic <span class="hlt">deformation</span> of the Ordos block and its surrounding orogenic belts. We investigated the effect of different dynamic regimes on the late Jurassic <span class="hlt">deformation</span> of this region. Our primary results suggest that strong and stable Ordos block remains undeformed despite its location at the center of a region of <span class="hlt">deformation</span>. East-west trending fold-and-thrust belts would have developed along the north and south edges of the Ordos block during the closure of the Mongolia-Okhotsk ocean or the collision between the North China and South China blocks. North-south trending fold-and-thrust belts would have developed along the east and west edges of the Ordos block due to subduction of the Pacific plate. However, the paleo-stress field in the late Jurassic indicates that the orientations of the maximum compressive principle stress were nearly perpendicular to the edge of the Ordos block and the compressive <span class="hlt">deformation</span> around it was coeval. It is difficult to explain the distribution of belts of <span class="hlt">deformation</span> with a single stress regime. Our numerical model reveals that multi-direction convergence pattern with time during the transformation of these three regimes can be used to interpret the formation and <span class="hlt">deformation</span> styles of ringed mountains around the Ordos block during the late</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009ursi.confE...1H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009ursi.confE...1H"><span id="translatedtitle">Removal of daytime thermal <span class="hlt">deformations</span> in the GBT <span class="hlt">active</span> surface via out-of-focus holography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hunter, T. R.; Mello, M.; Nikolic, B.; Mason, B. S.; Schwab, F. R.; Ghigo, F. D.; Dicker, S. R.</p> <p>2009-01-01</p> <p>The 100-m diameter Green Bank Telescope (GBT) was built with an <span class="hlt">active</span> surface of 2209 actuators in order to achieve and maintain an accurate paraboloidal shape. While much of the large-scale gravitational <span class="hlt">deformation</span> of the surface can be described by a finite element model, a significant uncompensated gravitational <span class="hlt">deformation</span> exists. In recent years, the elevation-dependence of this residual <span class="hlt">deformation</span> has been successfully measured during benign nighttime conditions using the out-of-focus (OOF) holography technique (Nikolic et al, 2007, A&A 465, 685). Parametrized by a set of Zernike polynomials, the OOF model correction was implemented into the <span class="hlt">active</span> surface and has been applied during all high frequency observations since Fall 2006, yielding a consistent gain curve that is constant with elevation. However, large-scale thermal <span class="hlt">deformation</span> of the surface has remained a problem for daytime high-frequency observations. OOF holography maps taken throughout a clear winter day indicate that surface <span class="hlt">deformations</span> become significant whenever the Sun is above 10 degrees elevation, but that they change slowly while tracking a single source. In this paper, we describe a further improvement to the GBT <span class="hlt">active</span> surface that allows an observer to measure and compensate for the thermal surface <span class="hlt">deformation</span> using the OOF technique. In order to support high-frequency observers, "AutoOOF" is a new GBT Astrid procedure that acquires a quick set of in-focus and out-of-focus on-the-fly continuum maps on a quasar using the currently <span class="hlt">active</span> receiver. Upon completion of the maps, the data analysis software is launched automatically which produces and displays the surface map along with a set of Zernike coefficients. These coefficients are then sent to the <span class="hlt">active</span> surface manager which combines them with the existing gravitational Zernike terms and FEM in order to compute the total <span class="hlt">active</span> surface correction. The end-to-end functionality has been tested on the sky at Q-Band and Ka</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26478398','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26478398"><span id="translatedtitle">Effect of bimodal harmonic structure design on the <span class="hlt">deformation</span> behaviour and <span class="hlt">mechanical</span> properties of Co-Cr-Mo alloy.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Vajpai, Sanjay Kumar; Sawangrat, Choncharoen; Yamaguchi, Osamu; Ciuca, Octav Paul; Ameyama, Kei</p> <p>2016-01-01</p> <p>In the present work, Co-Cr-Mo alloy compacts with a unique bimodal microstructural design, harmonic structure design, were successfully prepared via a powder metallurgy route consisting of controlled <span class="hlt">mechanical</span> milling of pre-alloyed powders followed by spark plasma sintering. The harmonic structured Co-Cr-Mo alloy with bimodal grain size distribution exhibited relatively higher strength together with higher ductility as compared to the coarse-grained specimens. The harmonic Co-Cr-Mo alloy exhibited a very complex <span class="hlt">deformation</span> behavior wherein it was found that the higher strength and the high retained ductility are derived from fine-grained shell and coarse-grained core regions, respectively. Finally, it was observed that the peculiar spatial/topological arrangement of stronger fine-grained and ductile coarse-grained regions in the harmonic structure promotes uniformity of strain distribution, leading to improved <span class="hlt">mechanical</span> properties by suppressing the localized plastic <span class="hlt">deformation</span> during straining. PMID:26478398</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFM.T53C1591B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFM.T53C1591B"><span id="translatedtitle">The three-dimensional pattern of crustal <span class="hlt">deformation</span> associated with <span class="hlt">active</span> normal fault systems observed using continuous GPS geodesy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bennett, R. A.; Hreinsdottir, S.</p> <p>2009-12-01</p> <p>Geological examples of shallow dipping normal faults with large displacements are exposed at numerous locations throughout the world and it is widely recognized that extensional <span class="hlt">deformation</span> at brittle crustal levels is most efficiently accomplished by slip across such structures. It has previously been shown that lower dip angles reduce the regional stresses required to drive large horizontal displacements. Nevertheless, the traditional theory of fault mechanics—based on Anderson’s classification of stress regimes, the Coulomb failure criterion, and Byerlee’s friction law—precludes such faults from slipping at low angle. Observational support for this traditional theory includes the absence of large unequivocally low-angle normal fault earthquakes in the global catalog; all well-determined normal fault earthquakes appear to have occurred on moderate to steeply dipping planes. However, precise measurements of 3D crustal motions based on continuous GPS in central Italy and Utah reveal <span class="hlt">deformation</span> patterns across <span class="hlt">active</span> normal fault systems that are inconsistent with <span class="hlt">active</span> slip across steeply dipping planes. Instead, the combination of observed horizontal and vertical surface motions are consistent with slip across low angle surfaces independently imaged in the subsurface by seismic reflection and other geophysical data. For the Alto Tiberina fault in central Italy, <span class="hlt">active</span> aseismic creep occurs at shallow crustal levels, most likely within the brittle-frictional regime at which Andersonian-Byerlee fault <span class="hlt">mechanics</span> should be applicable. The <span class="hlt">actively</span> creeping portion of the fault inferred using GPS geodesy correlates well with the observed pattern of micro-seismicity, which concentrates along the inferred subsurface fault plane. GPS measurements across the greater Wasatch fault zone in the vicinity of Salt Lake City, Utah, reveal crustal motions consistent with aseismic displacement across a shallow dipping fault or sub-horizontal shear zone at mid</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.cancer.gov/news-events/press-releases/2014/GlutamateReceptors','NCI'); return false;" href="https://www.cancer.gov/news-events/press-releases/2014/GlutamateReceptors"><span id="translatedtitle"><span class="hlt">Mechanism</span> for the <span class="hlt">activation</span> of glutamate receptors</span></a></p> <p><a target="_blank" href="http://www.cancer.gov">Cancer.gov</a></p> <p></p> <p></p> <p>Scientists at the NIH have used a technique called cryo-electron microscopy to determine a molecular <span class="hlt">mechanism</span> for the <span class="hlt">activation</span> and desensitization of ionotropic glutamate receptors, a prominent class of neurotransmitter receptors in the brain and spina</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25325848','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25325848"><span id="translatedtitle">Multiplexed fluidic plunger <span class="hlt">mechanism</span> for the measurement of red blood cell <span class="hlt">deformability</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Myrand-Lapierre, Marie-Eve; Deng, Xiaoyan; Ang, Richard R; Matthews, Kerryn; Santoso, Aline T; Ma, Hongshen</p> <p>2015-01-01</p> <p>The extraordinary <span class="hlt">deformability</span> of red blood cells gives them the ability to repeatedly transit through the microvasculature of the human body. The loss of this capability is part of the pathology of a wide range of diseases including malaria, hemoglobinopathies, and micronutrient deficiencies. We report on a technique for multiplexed measurements of the pressure required to <span class="hlt">deform</span> individual red blood cell through micrometer-scale constrictions. This measurement is performed by first infusing single red blood cells into a parallel array of ~1.7 μm funnel-shaped constrictions. Next, a saw-tooth pressure waveform is applied across the constrictions to squeeze each cell through its constriction. The threshold <span class="hlt">deformation</span> pressure is then determined by relating the pressure-time data with the video of the <span class="hlt">deformation</span> process. Our key innovation is a self-compensating fluidic network that ensures identical pressures are applied to each cell regardless of its position, as well as the presence of cells in neighboring constrictions. These characteristics ensure the consistency of the measurement process and robustness against blockages of the constrictions by rigid cells and debris. We evaluate this technique using in vitro cultures of RBCs infected with P. falciparum, the parasite that causes malaria, to demonstrate the ability to profile the <span class="hlt">deformability</span> signature of a heterogeneous sample. PMID:25325848</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010EGUGA..12.4196K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010EGUGA..12.4196K"><span id="translatedtitle"><span class="hlt">Mechanical</span> and mineralogical modifications of petrophysical parameters by <span class="hlt">deformation</span> bands in a hydrocarbon reservoir (Matzen, Austria)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaiser, Jasmin; Exner, Ulrike; Gier, Susanne; Hujer, Wolfgang</p> <p>2010-05-01</p> <p>In porous sedimentary rocks, fault zones are frequently accompanied by <span class="hlt">deformation</span> bands. These structures are tabular zones of displacement, where grain rotation and in some cases grain fracturing result in a significant reduction in porosity. Core samples were analyzed close to large normal faults from the most productive hydrocarbon reservoir in the Vienna Basin (Austria), the Matzen oil field. The Badenian terrigeneous sandstones contain predominately quartz, feldspar and dolomite as sub-rounded, detrial grains and are weakly cemented by chlorite and kaolinite. <span class="hlt">Deformation</span> bands occur as single bands of ca. 1-3 mm thickness and negligible displacement, as well as strands of several bands with up to 2 cm thickness and displacement of 1-2 cm. A dramatic porosity reduction can already be recognized macroscopically. In some samples, the corresponding reduction in permeability is highlighted by different degree of oil staining on either side of the bands. The mineralogical composition of the <span class="hlt">deformation</span> bands compared to the host rock does not indicate any preferential cementation or diagenetic growth of clay minerals or calcite. Instead, clay minerals are slightly enriched in the host sediment. These observations suggest that the formation of <span class="hlt">deformation</span> bands predates the cementation in the Matzen sands. Thus, we speculate that the porosity reduction is predominately caused by cataclastic grain size reduction. Identification of the grain scale processes of porosity and permeability reduction, in combination with the analysis of the spatial distribution and orientation of the <span class="hlt">deformation</span> bands may provide valuable information on the reservoir properties and fluid migration paths.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70014733','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70014733"><span id="translatedtitle">The <span class="hlt">mechanics</span> of ground <span class="hlt">deformation</span> precursory to dome-building extrusions at Mount St. Helens 1981-1982.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Chadwick, W.W., Jr.; Archuleta, R.J.; Swanson, D.A.</p> <p>1988-01-01</p> <p>Detailed monitoring at Mount St. Helens since 1980 has enabled prediction of the intermittent eruptive <span class="hlt">activity</span> (mostly dome growth) with unprecedented success. During 1981 and 1982, accelerating <span class="hlt">deformation</span> of the crater floor around the vent (including radial cracks, thrust faults, and ground tilt) was the earliest indicator of impending <span class="hlt">activity</span>. The magnitude of the shear stress required to match observed dipslacements (1-7 MPa) is inversely proportional to the conduit diameter (estimated to be 25-100 m). The most probable source of this shear stress is the flow of viscous magma up to the conduit and into the lava dome. A model is proposed in which the accelerating <span class="hlt">deformation</span>, beginning as much as 4 weeks before extrusions, is caused by the increasing velocity of ascending magma in the conduit. This model is examined by using <span class="hlt">deformation</span> data of the dome before four extrusions in 1981 and 1982 to estimate the volumetric flow rate through the conduit. This flow rate and an estimate of the effective viscosity of the magma enable calculation of an ascent velocity and an applied shear stress that, again, depend on the conduit diameter. The results of these calculations are consistent with the finite element experiments and show that the proposed model is feasible. Precursory <span class="hlt">deformation</span> like that measured at Mount St. Helens should be observable at similar volcanoes elsewhere because it is caused by the fundamental process of magma ascent.-from Authors</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1162078-deformation-mechanisms-precipitation-strengthened-ferritic-superalloy-revealed-situ-neutron-diffraction-studies-elevated-temperatures','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1162078-deformation-mechanisms-precipitation-strengthened-ferritic-superalloy-revealed-situ-neutron-diffraction-studies-elevated-temperatures"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K</p> <p>2014-10-22</p> <p>In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing <span class="hlt">mechanisms</span> during tensile <span class="hlt">deformation</span> of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticitymore » theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1210542','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1210542"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in a precipitation-strengthened ferritic super alloy revealed by in situ neutron dffraction studies at elevated temperatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Teng, Zhenke; Wu, Wei; Liaw, Peter K.</p> <p>2015-01-01</p> <p>The ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)AlB2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing <span class="hlt">mechanisms</span> during tensile <span class="hlt">deformation</span> of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26786065','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26786065"><span id="translatedtitle">Efficiency of five chemical protective clothing materials against nano and submicron aerosols when submitted to <span class="hlt">mechanical</span> <span class="hlt">deformations</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ben Salah, Mehdi; Hallé, Stéphane; Tuduri, Ludovic</p> <p>2016-01-01</p> <p>Due to their potential toxicity, the use of nanoparticles in the workplace is a growing concern. Some studies indicate that nanoparticles can penetrate the skin and lead to adverse health effects. Since chemical protective clothing is the last barrier to protect the skin, this study aims to better understand nanoparticle penetration behaviour in dermal protective clothing under <span class="hlt">mechanical</span> <span class="hlt">deformation</span>. For this purpose, five of the most common types of fabrics used in protective clothing, one woven and four nonwoven, were chosen and submitted to different simulated exposure conditions. They were tested against polydispersed NaCl aerosols having an electrical-mobility diameter between 14 and 400 nm. A bench-scale exposure setup and a sampling protocol was developed to measure the level of penetration of the aerosols through the material samples of disposable coveralls and lab coat, while subjecting them to <span class="hlt">mechanical</span> <span class="hlt">deformations</span> to simulate the conditions of usage in the workplace. Particle size distribution of the aerosol was determined upstream and downstream using a scanning mobility particle sizer (SMPS). The measured efficiencies demonstrated that the performances of nonwoven materials were similar. Three nonwovens had efficiencies above 99%, while the woven fabric was by far, the least effective. Moreover, the results established that <span class="hlt">mechanical</span> <span class="hlt">deformations</span>, as simulated for this study, did not have a significant effect on the fabrics' efficiencies. PMID:26786065</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1162078','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1162078"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanisms</span> in a precipitation-strengthened ferritic superalloy revealed by in situ neutron diffraction studies at elevated temperatures</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Huang, Shenyan; Gao, Yanfei; An, Ke; Zheng, Lili; Wu, Wei; Teng, Zhenke; Liaw, Peter K</p> <p>2014-10-22</p> <p>In this study, the ferritic superalloy Fe–10Ni–6.5Al–10Cr–3.4Mo strengthened by ordered (Ni,Fe)Al B2-type precipitates is a candidate material for ultra-supercritical steam turbine applications above 923 K. Despite earlier success in improving its room-temperature ductility, the creep resistance of this material at high temperatures needs to be further improved, which requires a fundamental understanding of the high-temperature <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> at the scales of individual phases and grains. In situ neutron diffraction has been utilized to investigate the lattice strain evolution and the microscopic load-sharing <span class="hlt">mechanisms</span> during tensile <span class="hlt">deformation</span> of this ferritic superalloy at elevated temperatures. Finite-element simulations based on the crystal plasticity theory are employed and compared with the experimental results, both qualitatively and quantitatively. Based on these interphase and intergranular load-partitioning studies, it is found that the <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> change from dislocation slip to those related to dislocation climb, diffusional flow and possibly grain boundary sliding, below and above 873 K, respectively. Insights into microstructural design for enhancing creep resistance are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1815037N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1815037N"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> of the northern front of the Eastern Great Caucasus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Niviere, Bertrand; Gagala, Lukasz; Callot, Jean-Paul; Regard, Vincent; Ringenbach, Jean-Claude</p> <p>2016-04-01</p> <p>The Arabia-Eurasia collision involved a mosaic of island arcs and microcontinents. Their accretion to the complex paleogeographic margin of Neotethys was marked by numerous collisional events. The Greater Caucasus constitute the northernmost tectonic element of this tectonic collage, developed as a back arc extensional zone now inverted, which relationships to the onset of Arabia-Eurasia continental collision and/or to the reorganization of the Arabia-Eurasia plate boundary at ˜5 Ma remain controversial. Structurally, the Greater Caucasus are a former continental back arc rift, now the locus of ongoing continental shortening. Modern geodetic observations suggest that in the west, the strain north of the Armenian Plateau is accommodated almost exclusively along the margins of the Greater Caucasus. This differs from regions further east where strain accommodation is distributed across both the Lesser and Greater Caucasus, and within the Greater Caucasus range, with a unique southward vergence. We question here the amount and <span class="hlt">mechanisms</span> by which the Eastern Greater Caucasus accommodate part of the Arabia-Eurasia convergence. Morphostructural analysis of the folded late Pleistocene marine terrace along the northern slope of the Eastern Greater Caucasus evidences an on going tectonic <span class="hlt">activity</span> in the area where GPS measurements record no motion. Most of the recent foreland <span class="hlt">deformation</span> is accommodated by south-vergent folds and thrust, i. e. opposite to the vergence of the Caucasus frontal northern thrust. A progressive unconformity in the folded beds shows that it was already <span class="hlt">active</span> during the late Pliocene. Cosmogenic dating of the terrace and kinematic restoration of the remnant terrace, linked to the subsurface geology allows for the estimation of a shortening rate ranging from a few mm/yr to 1 cm/yr over the last 5 Myr along the greater Caucasus northern front. Thus more than one third of the shortening between the Kura block / Lesser Caucasus domain and the Stable</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JSG....87...30W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JSG....87...30W&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Deformation</span> structures associated with the Trachyte Mesa intrusion, Henry Mountains, Utah: Implications for sill and laccolith emplacement <span class="hlt">mechanisms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, Penelope I. R.; McCaffrey, Ken J. W.; Wilson, Robert W.; Jarvis, Ian; Holdsworth, Robert E.</p> <p>2016-06-01</p> <p><span class="hlt">Deformation</span> structures in the wall rocks of igneous intrusions emplaced at shallow crustal depths preserve an important record of how space was created for magma in the host rocks. Trachyte Mesa, a small Oligocene age intrusion in the Henry Mountains, Utah, is composed of a series of stacked tabular, sheet-like intrusions emplaced at 3-3.5 km depth into sandstone-dominated sedimentary sequences of late Palaeozoic-Mesozoic age. New structural analysis of the spatial distribution, geometry, kinematics and relative timings of <span class="hlt">deformation</span> structures in the host rocks of the intrusion has enabled the recognition of distinct pre-, syn-, and late-stage-emplacement <span class="hlt">deformation</span> phases. Our observations suggest a two-stage growth <span class="hlt">mechanism</span> for individual sheets where radial growth of a thin sheet was followed by vertical inflation. Dip-slip faults formed during vertical inflation; they are restricted to the tips of individual sheets due to strain localisation, with magma preferentially exploiting these faults, initiating sill (sheet) climbing. The order in which sheets are stacked impacts on the intrusion geometry and associated <span class="hlt">deformation</span> of wall rocks. Our results offer new insights into the incremental intrusion geometries of shallow-level magmatic bodies and the potential impact of their emplacement on surrounding host rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012KARJ...24...23W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012KARJ...24...23W"><span id="translatedtitle">A study on the <span class="hlt">mechanical</span> properties and <span class="hlt">deformation</span> behavior of injection molded PMMA-TSP laminated composite</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Jaeyoon; Lee, Moon Kyu; Park, Seon-Mi; Hong, Seokmoo; Kim, Naksoo</p> <p>2012-03-01</p> <p>To evaluate the <span class="hlt">deformed</span> features of a polymer and touch screen panel laminated material and to secure a reliability of the design method, it is crucial to predict a thermo-<span class="hlt">mechanical</span> behavior of the polymers. The reliability problems of polymer-TSP laminated module subjected to temperature and humidity changes mainly occur due to features with time-dependent material properties as well as differences in the coefficients of thermal expansion between the polymer and TSP. Therefore, it is necessary to consider the viscous behavior which causes changes in material properties which include temperature-dependent properties along with the time-dependent properties. In this study, a tensile test is conducted to obtain fundamental material properties and a creep test is used to characterize viscous properties of the polymer. Material properties from the tensile and the creep test are verified by the tensile and creep simulations. Also, the finite element analysis is used to simulate the time-dependent behaviors during a high temperature conditions while predicting thermal <span class="hlt">deformations</span>. Numerical results are compared with experimental results. The result shows that the shape <span class="hlt">deformations</span> of the polymer-TSP laminated module calculated by the finite element analysis with visco-elastic-plastic material model are in a good agreement with the experiment. Based on analytical results, we predict the thermal <span class="hlt">deformation</span> of the PMMA-TSP composite plate in consideration of the effect of viscous features and set up the organized numerical analysis procedure using FE analysis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JSG....87...30W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JSG....87...30W"><span id="translatedtitle"><span class="hlt">Deformation</span> structures associated with the Trachyte Mesa intrusion, Henry Mountains, Utah: Implications for sill and laccolith emplacement <span class="hlt">mechanisms</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilson, Penelope I. R.; McCaffrey, Ken J. W.; Wilson, Robert W.; Jarvis, Ian; Holdsworth, Robert E.</p> <p>2016-06-01</p> <p><span class="hlt">Deformation</span> structures in the wall rocks of igneous intrusions emplaced at shallow crustal depths preserve an important record of how space was created for magma in the host rocks. Trachyte Mesa, a small Oligocene age intrusion in the Henry Mountains, Utah, is composed of a series of stacked tabular, sheet-like intrusions emplaced at 3-3.5 km depth into sandstone-dominated sedimentary sequences of late Palaeozoic-Mesozoic age. New structural analysis of the spatial distribution, geometry, kinematics and relative timings of <span class="hlt">deformation</span> structures in the host rocks of the intrusion has enabled the recognition of distinct pre-, syn-, and late-stage-emplacement <span class="hlt">deformation</span> phases. Our observations suggest a two-stage growth <span class="hlt">mechanism</span> for individual sheets where radial growth of a thin sheet was followed by vertical inflation. Dip-slip faults formed during vertical inflation; they are restricted to the tips of individual sheets due to strain localisation, with magma preferentially exploiting these faults, initiating sill (sheet) climbing. The order in which sheets are stacked impacts on the intrusion geometry and associated <span class="hlt">deformation</span> of wall rocks. Our results offer new insights into the incremental intrusion geometries of shallow-level magmatic bodies and the potential impact of their emplacement on surrounding host rocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JNuM..466..653S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JNuM..466..653S&link_type=ABSTRACT"><span id="translatedtitle">High temperature <span class="hlt">deformation</span> <span class="hlt">mechanism</span> of 15CrODS ferritic steels at cold-rolled and recrystallized conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sugino, Yoshito; Ukai, Shigeharu; Oono, Naoko; Hayashi, Shigenari; Kaito, Takeji; Ohtsuka, Satoshi; Masuda, Hiroshi; Taniguchi, Satoshi; Sato, Eiichi</p> <p>2015-11-01</p> <p>The ODS ferritic steels realize potentially higher operating temperature due to structural stability by the dispersed nano-size oxide particles. The <span class="hlt">deformation</span> process and <span class="hlt">mechanism</span> of 15CrODS ferritic steels were investigated at 1073 K and 1173 K for the cold-rolled and recrystallized conditions. Tensile and creep tests were conducted at the stress in parallel (LD) and perpendicular (TD) directions to the grain boundaries. Strain rate varied from 10-1 to 10-9 s-1. For the LD specimens, <span class="hlt">deformation</span> in the cold rolled and recrystallized conditions is reinforced by finely dispersed oxide particles. The dominant <span class="hlt">deformation</span> process for the recrystallized TD specimen is controlled through the grain boundary sliding and stress accommodation via diffusional creep at temperature of 1173 K and lower strain rate less than 10-4 s-1. The grain boundary sliding couldn't be rate-controlling process at 1073 K for the as-cold rolled TD specimen, where a dynamic recovery of the dislocation produced by cold-rolling is related to the <span class="hlt">deformation</span> process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/891063','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/891063"><span id="translatedtitle"><span class="hlt">Mechanical</span> <span class="hlt">Deformation</span> of KD2xH2(1-x)PO4</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kucheyev, S; Siekhaus, W; Land, T; Demos, S</p> <p>2003-11-10</p> <p>The <span class="hlt">deformation</span> behavior of rapidly-grown tetragonal KD{sub 2x} H{sub 1(1-x)} PO{sub 4} (KDP and DKDP) single crystals, with a deuteration degree x of 0.0, 0.3, and 0.6, is studied by nanoindentation with a 1 {micro}m radius spherical indenter. Within experimental error, the <span class="hlt">deformation</span> behavior is found to be independent of deuterium content and different for (001) and (100) surfaces. Multiple discontinuities (so called ''pop-in'' events) in force-displacement curves are observed during indentation loading, but not during unloading. Slip is identified as the major mode of plastic <span class="hlt">deformation</span> in DKDP, and pop-in events are attributed to the initiation of slip.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.T43B3000B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.T43B3000B"><span id="translatedtitle">Dissecting Oceanic Detachment Faults: Fault Zone Geometry, <span class="hlt">Deformation</span> <span class="hlt">Mechanisms</span>, and Nature of Fluid-Rock Interactions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bonnemains, D.; Escartin, J.; Verlaguet, A.; Andreani, M.; Mevel, C.</p> <p>2015-12-01</p> <p>To understand the extreme strain localization at long-lived oceanic detachment faults rooting deeply below the axis, we present results of geological investigations at the 13°19'N detachment along the Mid-Atlantic Ridge, conducted during the ODEMAR cruise (Nov-Dec13, NO Pourquoi Pas?) with ROV Victor6000 (IFREMER). During this cruise we investigated and sampled the corrugated fault to understand its geometry, nature of <span class="hlt">deformation</span>, and links to fluid flow. We identified and explored 7 fault outcrops on the flanks of microbathymetric striations subparallel to extension. These outcrops expose extensive fault planes, with the most prominent ones extending 40-90m laterally, and up to 10 m vertically. These fault surfaces systematically show subhorizontal striations subparallel to extension, and define slabs of fault-rock that are flat and also striated at sample scale. Visual observations show a complex detachment fault zone, with anastomosing fault planes at outcrop scale (1-10 m), with a highly heterogeneous distribution of <span class="hlt">deformation</span>. We observe heterogeneity in fault-rock nature at outcrop scale. In situ samples from striated faults are primarily basalt breccias with prior green-schist facies alteration, and a few ultramafic fault-rocks that show a complex <span class="hlt">deformation</span> history, with early schistose textures, brittlely reworked as clasts within the fault. The basalt breccias show variable silicification and associated sulfides, recording important fluid-rock interactions during exhumation. To understand the link between fluid and <span class="hlt">deformation</span> during exhumation, we will present microstructural observation of <span class="hlt">deformation</span> textures, composition, and distribution and origin of quartz and sulfides, as well as constraints on the temperature of silicifying fluids from fluid inclusions in quartz. These results allow us to characterize in detail the detachment fault zone geometry, and investigate the timing of silicification relative to <span class="hlt">deformation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MMTA...46.4669V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MMTA...46.4669V"><span id="translatedtitle">Assessment of Tungsten Content on Tertiary Creep <span class="hlt">Deformation</span> Behavior of Reduced <span class="hlt">Activation</span> Ferritic-Martensitic Steel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vanaja, J.; Laha, Kinkar</p> <p>2015-10-01</p> <p>Tertiary creep <span class="hlt">deformation</span> behavior of reduced <span class="hlt">activation</span> ferritic-martensitic (RAFM) steels having different tungsten contents has been assessed. Creep tests were carried out at 823 K (550 °C) over a stress range of 180 to 260 MPa on three heats of the RAFM steel (9Cr-W-0.06Ta-0.22V) with tungsten content of 1, 1.4, and 2.0 wt pct. With creep exposure, the steels exhibited minimum in creep rate followed by progressive increase in creep rate until fracture. The minimum creep rate decreased, rupture life increased, and the onset of tertiary stage of creep <span class="hlt">deformation</span> delayed with the increase in tungsten content. The tertiary creep behavior has been assessed based on the relationship, , considering minimum creep rate () instead of steady-state creep rate. The increase in tungsten content was found to decrease the rate of acceleration of tertiary parameter ` p.' The relationships between (1) tertiary parameter `p' with minimum creep rate and time spent in tertiary creep <span class="hlt">deformation</span> and (2) the final creep rate with minimum creep rate revealed that the same first-order reaction rate theory prevailed in the minimum creep rate as well as throughout the tertiary creep <span class="hlt">deformation</span> behavior of the steel. A master tertiary creep curve of the steels has been developed. Scanning electron microscopic investigation revealed enhanced coarsening resistance of carbides in the steel on creep exposure with increase in tungsten content. The decrease in tertiary parameter ` p' with tungsten content with the consequent decrease in minimum creep rate and increase in rupture life has been attributed to the enhanced microstructural stability of the steel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013OptEn..52i1803L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013OptEn..52i1803L"><span id="translatedtitle">Mirror <span class="hlt">actively</span> <span class="hlt">deformed</span> and regulated for applications in space: design and performance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Laslandes, Marie; Hugot, Emmanuel; Ferrari, Marc; Hourtoule, Claire; Singer, Christian; Devilliers, Christophe; Lopez, Céline; Chazallet, Frédéric</p> <p>2013-09-01</p> <p>The need for both high quality images and lightweight structures is one of the main drivers in space telescope design. An efficient wavefront control system will become mandatory in future large observatories, retaining performance while relaxing specifications in the global system's stability. We present the mirror <span class="hlt">actively</span> <span class="hlt">deformed</span> and regulated for applications in space project, which aims to demonstrate the applicability of <span class="hlt">active</span> optics for future space instrumentation. It has led to the development of a 24-actuator, 90-mm-diameter <span class="hlt">active</span> mirror, able to compensate for large lightweight primary mirror <span class="hlt">deformations</span> in the telescope's exit pupil. The correcting system has been designed for expected wavefront errors from 3-m-class lightweight primary mirrors, while also taking into account constraints for space use. Finite element analysis allowed an optimization of the system in order to achieve a precision of correction better than 10 nm rms. A dedicated testbed has been designed to fully characterize the integrated system performance in representative operating conditions. It is composed of: a telescope simulator, an <span class="hlt">active</span> correction loop, a point spread function imager, and a Fizeau interferometer. All conducted tests demonstrated the correcting mirror performance and has improved this technology maturity to a TRL4.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSG....74..117Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSG....74..117Z"><span id="translatedtitle">Impact of solid second phases on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of naturally <span class="hlt">deformed</span> salt rocks (Kuh-e-Namak, Dashti, Iran) and rheological stratification of the Hormuz Salt Formation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Závada, P.; Desbois, G.; Urai, J. L.; Schulmann, K.; Rahmati, M.; Lexa, O.; Wollenberg, U.</p> <p>2015-05-01</p> <p>Viscosity contrasts displayed in flow structures of a mountain namakier (Kuh-e-Namak - Dashti), between 'weak' second phase bearing rock salt and 'strong' pure rock salt types are studied for <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> using detailed quantitative microstructural study. While the solid inclusions rich ("dirty") rock salts contain disaggregated siltstone and dolomite interlayers, "clean" salts reveal microscopic hematite and remnants of abundant fluid inclusions in non-recrystallized cores of porphyroclasts. Although the flow in both, the recrystallized "dirty" and "clean" salt types is accommodated by combined <span class="hlt">mechanisms</span> of pressure-solution creep (PS), grain boundary sliding (GBS), transgranular microcracking and dislocation creep accommodated grain boundary migration (GBM), their viscosity contrasts observed in the field outcrops are explained by: 1) enhanced ductility of "dirty" salts due to increased diffusion rates along the solid inclusion-halite contacts than along halite-halite contacts, and 2) slow rates of intergranular diffusion due to dissolved iron and inhibited dislocation creep due to hematite inclusions for "clean" salt types Rheological contrasts inferred by microstructural analysis between both salt rock classes apply in general for the "dirty" salt forming Lower Hormuz and the "clean" salt forming the Upper Hormuz of the Hormuz Formation and imply strain rate gradients or decoupling along horizons of mobilized salt types of different composition and microstructure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JSAES..64..339O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JSAES..64..339O"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> in the northern Sierra de Valle Fértil, Sierras Pampeanas, Argentina</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ortiz, Gustavo; Alvarado, Patricia; Fosdick, Julie C.; Perucca, Laura; Saez, Mauro; Venerdini, Agostina</p> <p>2015-12-01</p> <p>The Western Sierras Pampeanas region in the San Juan Province is characterized by thick-skinned <span class="hlt">deformation</span> with approximately N-S trending ranges of average heights of 2500 m and a high frequency occurrence of seismic <span class="hlt">activity</span>. Its location to the east of the mainly thin-skinned tectonics of the Argentine Precordillera fold-and-thrust belt suggests that at 30°S, <span class="hlt">deformation</span> is concentrated in a narrow zone involving these two morphostructural units. In this paper, we present new apatite (U-Th)/He results (AHe) across the northern part of the Sierra de Valle Fértil (around 30°S) and analyze them in a framework of thermochronologic available datasets. We found Pliocene AHe results for Carboniferous and Triassic strata in the northern Sierra de Valle Fértil consistent with the hypothesis of recent cooling and inferred erosional denudation concentrated along the northern end of this mountain range. Our analysis shows that this northern region may have evolved under different conditions than the central part of the Sierra de Valle Fértil. Previous studies have observed AHe ages consistent with Permian through Cretaceous cooling, indicating the middle part of the Sierra de Valle Fértil remained near surface before the Pampean slab subduction flattening process. Those studies also obtained ˜5 My cooling ages in the southern part of the Sierra de Valle Fértil, which are similar to our results in the northern end of the range. Taken together, these results suggest a pattern of young <span class="hlt">deformation</span> in the northern and southern low elevation ends of the Sierra de Valle Fértil consistent with regions of high seismic <span class="hlt">activity</span>, and Quaternary <span class="hlt">active</span> faulting along the western-bounding thrust fault of the Sierra de Valle Fértil.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRB..120.8240M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRB..120.8240M"><span id="translatedtitle">Low resistivity and permeability in <span class="hlt">actively</span> <span class="hlt">deforming</span> shear zones on the San Andreas Fault at SAFOD</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Morrow, C.; Lockner, D. A.; Hickman, S.</p> <p>2015-12-01</p> <p>The San Andreas Fault Observatory at Depth (SAFOD) scientific drill hole near Parkfield, California, crosses the San Andreas Fault at a depth of 2.7 km. Downhole measurements and analysis of core retrieved from Phase 3 drilling reveal two narrow, <span class="hlt">actively</span> <span class="hlt">deforming</span> zones of smectite-clay gouge within a roughly 200 m wide fault damage zone of sandstones, siltstones, and mudstones. Here we report electrical resistivity and permeability measurements on core samples from all of these structural units at effective confining pressures up to 120 MPa. Electrical resistivity (~10 Ω-m) and permeability (10-21 to 10-22 m2) in the <span class="hlt">actively</span> <span class="hlt">deforming</span> zones were 1 to 2 orders of magnitude lower than the surrounding damage zone material, consistent with broader-scale observations from the downhole resistivity and seismic velocity logs. The higher porosity of the clay gouge, 2 to 8 times greater than that in the damage zone rocks, along with surface conduction were the principal factors contributing to the observed low resistivities. The high percentage of fine-grained clay in the <span class="hlt">deforming</span> zones also greatly reduced permeability to values low enough to create a barrier to fluid flow across the fault. Together, resistivity and permeability data can be used to assess the hydrogeologic characteristics of the fault, key to understanding fault structure and strength. The low resistivities and strength measurements of the SAFOD core are consistent with observations of low resistivity clays that are often found in the principal slip zones of other <span class="hlt">active</span> faults making resistivity logs a valuable tool for identifying these zones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22043989','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22043989"><span id="translatedtitle">Measurement of the <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of an elastic spherical shell, filled with an incompressible fluid, with the help of a semiconductor laser autodyne</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Usanov, D A; Skripal, A V; Dobdin, S Yu</p> <p>2012-04-30</p> <p>We report the possibility of measuring <span class="hlt">mechanical</span> <span class="hlt">deformations</span> of an elastic spherical shell filled with an incompressible fluid under the action of an air pulse. The value of the <span class="hlt">deformation</span> was determined by the semiconductor laser autodyne signal using a wavelet transform. It is established that it correlates with the internal pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9219E..0PE','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9219E..0PE"><span id="translatedtitle">A monolithic <span class="hlt">deformable</span> mirror with latchable <span class="hlt">mechanical</span> actuation (LATCHAMAN) for space-borne telescopes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Enya, Keigo; Kataza, Hirokazu; Fukushima, Mitsuhiro; Mitsui, Kenji; Okada, Norio; Iwashita, Hikaru; Haze, Kanae; Takahashi, Aoi; Kotani, Takayuki; Yamamuro, Tomoyasu; Kobayashi, Hitomi</p> <p>2014-09-01</p> <p>We present the concept, design, fabrication, and evaluation of a new <span class="hlt">deformable</span> mirror (DM), which is latchable, compact, and designed to be applicable for cryogenic environments. The main body of a prototype DM was fabricated from a monolithic cuboid of aluminum using wire electrical discharge machining (EDM). A flexible structure was constructed inside the block by 3-dimensionally crossed hollowing using the EDM. The prototype has 6 × 6 channels, and its volume is 27 mm × 27 mm × 30 mm. The mirror was formed on the surface of the aluminum block using a highprecision NC lathe. The surface figure of the mirror was evaluated and 34 nm rms was obtained. The evaluated surface roughness for the center and off-center areas of the mirror was 9.2 nm rms and 7.6 nm rms, respectively Screws set at the back of the block <span class="hlt">deform</span> the mirror via springs and the internal flexible structure. We present our first demonstration of <span class="hlt">deformation</span> of the mirror carried out at ambient temperature. The relationship between the displacement of the screws and the <span class="hlt">deformation</span> of the mirror was evaluated. Consequently, a linear relationship was confirmed, and no significant hysteresis was found. The application of such mirrors to telescopes used for various different objectives is discussed. We conclude that a DM based on our concept can be used for wavefront correction of space-borne telescopes, especially in the infrared wavelength region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.1845R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.1845R&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformations</span> of the Jura arc inferred by GPS and seismotectonics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rabin, Mickael; Sue, Christian; Walpersdorf, Andrea</p> <p>2016-04-01</p> <p>The Jura Mountain is the most recent expression of the alpine orogeny. At the northern end of the western Alps, its recent <span class="hlt">deformation</span> is still a matter of debates. GPS data available in the Jura bear witness of disagreement between studies, as interpretations vary from uplifted belt to arc-parallel extension (Walpersdorf, et al., 2006) and very slow horizontal movements. Moreover, the traditionally accepted model of an <span class="hlt">active</span> collisional <span class="hlt">activity</span> of the Jura, in the dynamic continuity of the Alps, rises up the matter of its geodynamic origin. Indeed, the European Alps are in a post-collisional regime characterized by isostatic-related extension and uplift driven by interaction between buoyancy forces and erosional dynamics (e.g. Sue et al. 2007; Champagnac, et al., 2007; Vernant, et al., 2013.). We present a reappraisal of published focal <span class="hlt">mechanisms</span> combined with a new GPS solution over the entire arc and surrounding areas. Although the Jura presents a low seismic <span class="hlt">activity</span>, 53 focal <span class="hlt">mechanisms</span> over the Jura have been inverted in order to infer the current stress field. Anyhow, we tested several combinations of f.m. inversions, by structural zones, in order to test the regional stress stability. It appears that the current stress field is very stable all over the arc, and following our different sub-datasets. Indeed, the stress field shows a stable near horizontal NW-SE-oriented s1, associated to a NE-SW-oriented s3. Therefore, the structural arc of the Jura seems to have very low or no impact in terms of current stress. Complementarily, we present preliminary velocity and strain fields from a GPS network composed of 25 permanent stations implemented between 1998 and 2014 all around the Jura arc. Indeed, we also integrated the recent GPS-JURA station (OSU THETA Besançon), but they are still too young to accurately constrain the strain of the belt. Preliminary results exhibit very slow velocities across the arc in term of baselines evolution, with infra</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Tectp.676....1T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Tectp.676....1T"><span id="translatedtitle">Microfabrics and 3D grain shape of Gorleben rock salt: Constraints on <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and paleodifferential stress</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thiemeyer, Nicolas; Zulauf, Gernold; Mertineit, Michael; Linckens, Jolien; Pusch, Maximilian; Hammer, Jörg</p> <p>2016-04-01</p> <p>The Permian Knäuel- and Streifensalz formations (z2HS1 and z2HS2) are main constituents of the Gorleben salt dome (Northern Germany) and show different amounts and distributions of anhydrite. The reconstruction of 3D halite grain shape ellipsoids reveals small grain size (3.4 ± 0.6 mm) and heterogeneous grain shapes in both formations, the latter attributed to the polyphase <span class="hlt">deformation</span> of the rock salt during diapirism. The halite microfabrics of both formations indicate that strain-induced grain boundary migration was <span class="hlt">active</span> during <span class="hlt">deformation</span>. Crystal plastic <span class="hlt">deformation</span> of halite is further documented by lattice bending, subgrain formation and minor subgrain rotation. Evidence for pressure solution of halite has not been found, but cannot be excluded because of the small grain size, the lack of LPO and the low differential stress (1.1-1.3 MPa) as deduced from subgrain-size piezometry. Anhydrite has been <span class="hlt">deformed</span> in the brittle-ductile regime by solution precipitation creep, minor dislocation creep and brittle boudinage. No continuous anhydrite layers are preserved, and halite has acted as a sealing matrix embedding the disrupted anhydrite fragments prohibiting any potential migration pathways for fluids. Thus, anhydrite should not have a negative effect on the barrier properties of the Gorleben rock salts investigated in this study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015RMRE...48.2551G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015RMRE...48.2551G"><span id="translatedtitle">Attenuation Properties of Fontainebleau Sandstone During True-Triaxial <span class="hlt">Deformation</span> using <span class="hlt">Active</span> and Passive Ultrasonics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goodfellow, S. D.; Tisato, N.; Ghofranitabari, M.; Nasseri, M. H. B.; Young, R. P.</p> <p>2015-11-01</p> <p><span class="hlt">Active</span> and passive ultrasonic methods were used to study the evolution of attenuation properties in a sample of Fontainebleau sandstone during true-triaxial <span class="hlt">deformation</span>. A cubic sample of Fontainebleau sandstone (80 mm × 80 mm × 80 mm) was <span class="hlt">deformed</span> under true-triaxial stresses until failure. From the stress state: σ _3 = 5 MPa and σ _1 = σ _2 = 35 MPa, σ _1 was increased at a constant displacement rate until the specimen failed. Acoustic emission (AE) <span class="hlt">activity</span> was monitored by 18 piezoelectric sensors and bandpass filtered between 100 kHz and 1 MHz. A source location analysis was performed on discrete AE data harvested from the continuous record where 48,502 events were locatable inside the sample volume. AE sensors were sequentially pulsed during periodic P-wave surveys among 135 raypaths. Analytical solutions for Biot, squirt flow, viscous shear, and scattering attenuation were used to discuss to observed attenuation at various stages of the experiment. We concluded that initial attenuation anisotropy was stress induced and resulted from friction and squirt flow. Later attenuation of the high-frequency spectrum was attributed to scattering as a result of the formation of large macroscopic vertical fractures. Passive (AE) ultrasonic data produced similar information to that from <span class="hlt">active</span> data but with enhanced temporal and spacial resolution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/264482','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/264482"><span id="translatedtitle"><span class="hlt">Deformation</span> <span class="hlt">mechanism</span> of basic rock during long-term compression: Area of HLW repository design, Chelyabinsk District, Russia</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Petrov, V.A.; Zviagintsev, L.I.; Poluektov, V.V.</p> <p>1996-08-01</p> <p>A combination of ultrasound, <span class="hlt">mechanical</span> and petrographic results for long-term experimental compression of greenschist facies porphyritic andesite tuffs indicate a <span class="hlt">deformation</span> <span class="hlt">mechanism</span> that depends upon the mineral composition, textural-structural features of the rocks and the orientation of compression relative to the rock textures. Three dry samples of rock were investigated. Coaxial compression of a massive sample for 816 hours and a foliated sample for 1,176 hours (pressure orthogonal to foliation) is characterized by solidification when the rocks are temporarily metastable. Compressive strength of the first sample is 850 kg/cm{sup 2} and of the second one, 800 kg/cm{sup 2}. Experimentally, the rock behavior changes from a plastic to a brittle regime of <span class="hlt">deformation</span>. In contrast, compression of the foliated sample parallel to foliation causes disintegration along the foliation within 480 hours without solidification. The rock is liable to brittle <span class="hlt">deformation</span> and its compressive strength is 500 kg/cm{sup 2}. These results may have implications for characterization of near-field processes in connection with numerous subhorizontal zones of schistosity within the strata that are targeted for underground disposal of high-level wastes (HLW) in the Mayak radiochemical complex area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JSG....20..195J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JSG....20..195J"><span id="translatedtitle"><span class="hlt">Mechanisms</span> of shear localization in the continental lithosphere: inference from the <span class="hlt">deformation</span> microstructures of peridotites from the Ivrea zone, northwestern Italy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jin, Denghui; Karato, Shun-ichiro; Obata, Masaaki</p> <p>1998-03-01</p> <p>The ultramafic massif of Balmuccia, northwestern Italy, shows a variety of <span class="hlt">deformation</span> fabrics including some localized shear zones that resulted in nearly complete melting (pseudotachylyte). A series of peridotite specimens were collected near one of the pseudotachylyte fault veins to investigate the <span class="hlt">mechanisms</span> of shear localization. The microstructural analyses show at least three <span class="hlt">deformation</span> stages. The first (stage I) is nearly homogeneous <span class="hlt">deformation</span> at low stress (~ 3 MPa) and high temperature (~ 1300-1500 K), followed by localized <span class="hlt">deformation</span> (stage II) at a higher stress (~ 60 MPa) and moderate temperature (~ 1000-1150 K) and, finally, semi-brittle <span class="hlt">deformation</span> (stage III) at a very high stress (~ 400 MPa) that resulted in the formation of pseudotachylyte. The stage II <span class="hlt">deformation</span> resulted in relatively small strains in most areas but significant localized <span class="hlt">deformation</span> leading to dynamic recrystallization occurred, the degree of which increases systematically toward the fault zone. Based on this observation, together with the observation that the brittle <span class="hlt">deformation</span> post-dated dynamic recrystallization, we conclude that the shear localization in this locality occurred as a result of ductile <span class="hlt">deformation</span> rather than brittle <span class="hlt">deformation</span>. Various <span class="hlt">mechanisms</span> of shear localization in the ductile regime are examined and we conclude that the grain-size reduction due to dynamic recrystallization at relatively high stresses and moderate temperatures is a probable <span class="hlt">mechanism</span> of shear localization. The intermediate regime between dislocation and diffusion creep, where rheology is grain-size-sensitive yet continuous recrystallization occurs due to dislocation creep, is suggested to play an important role in shear localization in the upper mantle. The conditions of shear localization due to this <span class="hlt">mechanism</span> are examined based on the laboratory data on creep and dynamic recrystallization. It is shown that shear localization occurs at relatively low temperatures and/or high</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.5017F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013EGUGA..15.5017F&link_type=ABSTRACT"><span id="translatedtitle">Distribution of <span class="hlt">deformation</span> on an <span class="hlt">active</span> normal fault network, NW Corinth Rift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ford, Mary; Meyer, Nicolas; Boiselet, Aurélien; Lambotte, Sophie; Scotti, Oona; Lyon-Caen, Hélène; Briole, Pierre; Caumon, Guillaume; Bernard, Pascal</p> <p>2013-04-01</p> <p>Over the last 20-25 years, geodetic measurements across the Gulf of Corinth have recorded high extension rates varying from 1.1 cm/a in the east to a maximum of 1.6 cm/a in the west. Geodetic studies also show that current <span class="hlt">deformation</span> is confined between two relatively rigid blocks defined as Central Greece (to the north) and the Peloponnesus to the south. <span class="hlt">Active</span> north dipping faults (<1 Ma) define the south coast of the subsiding Gulf, while high seismicity (major earthquakes and micro-seismicity) is concentrated at depth below and to the north of the westernmost Gulf. How is this intense <span class="hlt">deformation</span> distributed in the upper crust? Our objectives here are (1) to propose two models for the distribution of <span class="hlt">deformation</span> in the upper crust in the westernmost rift since 1 Ma, and (2) to place the tectonic behaviour of the western Gulf in the context of longer term rift evolution. Over 20 major <span class="hlt">active</span> normal faults have been identified in the CRL area based specific characteristics (capable of generating earthquakes M> 5.5, <span class="hlt">active</span> in the last 1 M yrs, slip rate >0.5 mm/a). Because of the uncertainty related to fault geometry at depth two models for 3D fault network geometry in the western rift down to 10 km were constructed using all available geophysical and geological data. The first model assumes planar fault geometries while the second uses listric geometries for major faults. A model for the distribution of geodetically-defined extension on faults is constructed along five NNE-SSW cross sections using a variety of data and timescales. We assume that the role of smaller faults in accommodating <span class="hlt">deformation</span> is negligible so that extension is fully accommodated on the identified major faults. Uncertainties and implications are discussed. These models provide estimates of slip rate for each fault that can be used in seismic hazard models. A compilation of onshore and offshore data shows that the western Gulf is the youngest part of the Corinth rift having initiated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.V51E2724W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.V51E2724W"><span id="translatedtitle">Characterising Seismicity at Alutu, an <span class="hlt">Actively</span> <span class="hlt">Deforming</span> Volcano in the Main Ethiopian Rift</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilks, M.; Nowacki, A.; Kendall, J. M.; Wookey, J. M.; Biggs, J.; Bastow, I. D.; Ayele, A.; Bedada, T.</p> <p>2013-12-01</p> <p>The Main Ethiopian Rift (MER) provides a unique example of the tectonic and volcanic processes occuring during the transition from continental rifting to oceanic spreading. Situated 100 km south of Addis Ababa along the eastern rift margin, Alutu is a silicic stratovolcano that geodetic measurements (InSAR and GPS) have shown is <span class="hlt">actively</span> <span class="hlt">deforming</span>. Though the volcano has received relatively little scientific attention it is also a site of economic significance as a geothermal power plant resides within the caldera. As part of ARGOS (Alutu Research Geophysical ObservationS), a multi-disciplinary project aiming to investigate the magmatic and hydrothermal processes occuring at Alutu, a seismic network of 12 broadband seismometers was deployed in January 2012. Other components of ARGOS include InSAR, GPS, geologic mapping and magnetotellurics. From the seismic dataset, P- and S-wave arrivals across the array were manually picked and used to locate events using a non-linear earthquake location algorithm (NonLinLoc) and a predefined 1D velocity model. Perturbations were later applied to this velocity model to investigate the sensitivity of the locations and evaluate the true uncertainties of the solutions. Over 1000 events were successfully located during 2012, where picks were possible at 4 or more stations. Seismicity clusters at both shallow depths (z<2 km) beneath the caldera and at deeper depths of 5-15 km. There is a significant increase in seismicity during the rainy months, suggesting the shallow events may be related to the hydrothermal system. We interpret the deeper events as being magmatic in origin. Events are also located along the eastern border faults that bound the outer edges of the MER and highlights that seismicity arises concurrently via tectonic processes. An adapted version of Richter's original local magnitude scale (ML) to account for attenuation within the MER (Keir et al., 2006) was then used to compute magnitudes for the best located events</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/23663058','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/23663058"><span id="translatedtitle"><span class="hlt">Mechanism</span> of persulfate <span class="hlt">activation</span> by phenols.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Ahmad, Mushtaque; Teel, Amy L; Watts, Richard J</p> <p>2013-06-01</p> <p>The <span class="hlt">activation</span> of persulfate by phenols was investigated to further the understanding of persulfate chemistry for in situ chemical oxidation (ISCO). Phenol (pKa = 10.0) <span class="hlt">activated</span> persulfate at pH 12 but not at pH 8, suggesting <span class="hlt">activation</span> occurred only via the phenoxide form. Evaluation of the phenoxide <span class="hlt">activation</span> <span class="hlt">mechanism</span> was complicated by the concurrent <span class="hlt">activation</span> of persulfate by hydroperoxide anion, which is generated by the base catalyzed hydrolysis of persulfate. Therefore, phenoxide <span class="hlt">activation</span> was investigated using pentachlorophenoxide at pH 8.3, midway between the pKa of pentachlorophenol (pKa = 4.8) and that of hydrogen peroxide (pKa = 11.8). Of the two possible <span class="hlt">mechanisms</span> for phenoxide <span class="hlt">activation</span> of persulfate (reduction or nucleophilic attack) the results were consistent with reduction of persulfate by phenoxide with oxidation of the phenoxide. The concentration of phenoxide required for maximum persulfate <span class="hlt">activation</span> was low (1 mM). The results of this research document that phenoxides <span class="hlt">activate</span> persulfate via reduction; phenolic moieties ubiquitous to soil organic matter in the subsurface may have a significant role in the <span class="hlt">activation</span> of persulfate during its injection into the subsurface for ISCO. Furthermore, the results provide the foundation for <span class="hlt">activation</span> of persulfate by other organic anions without the toxicity of phenols, such as keto acids. PMID:23663058</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013APS..MAR.H1187H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013APS..MAR.H1187H"><span id="translatedtitle">Effect of substrate <span class="hlt">mechanical</span> properties on T cell <span class="hlt">activation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hui, King; Upadhyaya, Arpita</p> <p>2013-03-01</p> <p>T cell <span class="hlt">activation</span> is a key process in cell-mediated immunity, and engagement of T cell receptors by peptides on antigen presenting cells leads to <span class="hlt">activation</span> of signaling cascades as well as cytoskeletal reorganization and large scale membrane <span class="hlt">deformations</span>. While significant advances have been made in understanding the biochemical signaling pathways, the effects imposed by the physical environment and the role of <span class="hlt">mechanical</span> forces on cell <span class="hlt">activation</span> are not well understood. In this study, we have used anti-CD3 coated elastic polyacrylamide gels as stimulatory substrates to enable the spreading of Jurkat T cells and the measurement of cellular traction forces. We have investigated the effect of substrate stiffness on the dynamics of T cell spreading and cellular force generation. We found that T cells display more <span class="hlt">active</span> and sustained edge dynamics on softer gels and that they exert increased traction stresses with increasing gel stiffness. A dynamic actin cytoskeleton was required to maintain the forces generated during <span class="hlt">activation</span>, as inferred from small molecule inhibition experiments. Our results indicate an important role for physical properties of the antigen presenting cell as well as cytoskeleton-driven forces in signaling <span class="hlt">activation</span>.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.G41A0915P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.G41A0915P"><span id="translatedtitle">The role of the Montello hill in the seismicity and <span class="hlt">active</span> <span class="hlt">deformation</span> of Southern Alps</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pondrelli, S.; Serpelloni, E.; Danesi, S.; Lovati, S.; Massa, M.; Mastrolembo Ventura, B.; Danecek, P.; Cavaliere, A.; Salimbeni, S.</p> <p>2013-12-01</p> <p>The most remarkable geomorphological feature of the eastern Southern Alps (northern Italy) is the Montello anticline, a ~15km long SSW-NNE elongated hill, sited ~40km north of Venice, and offset of ~15 km to the south from the main pede-Alpine thrust front. It has been generated by the uplift and the <span class="hlt">deformation</span> produced by a S-verging blind thrust, constrained by morphotectonic analyses of uplifted river terraces and sub-surface data. Despite it is presently considered as one of the main S-verging seismogenic segments of the tectonically <span class="hlt">active</span> Southern Alps thrust front, its real seismogenic potential is still matter of debate. Although the area has been hit in 1695 by a Mw 6.5 earthquake, the Montello is currently characterized by slower seismicity <span class="hlt">activity</span> than its confining segments and geodetic <span class="hlt">deformation</span> rates are at the mm/yr level. In order to study the present day crustal <span class="hlt">deformation</span> at the fault-scale and to improve the detection of background seismicity associated to the 'seismically silent' Montello thrust and to understand its interseismic behavior, we have installed a temporary multi-parametric geophysical network, which integrates space geodetic (GPS) and seismological observations during the 2010-2011 time-interval, running semi-continuous GPS experiments from 2009 to 2013. We recorded 142 local events (compared to the 43 events located by the Italian Seismic Network), located with good reliability (rms < 0.5) with Ml between 1.5 and 3.5. The available continuous and semi-continuous GPS data show that ~2 mm/yr of N-S convergence are accommodated across this sector of the Southern Alps, but the <span class="hlt">deformation</span> signal appears more complex than what expected by a single thrust fault. GPS, although preliminary and not sampling optimally possible lateral variations of the strain-rate field, show a remarkable change of the kinematics across the external Montello thrust front. The GPS and seismological data collected during the experiment suggest that the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/15132184','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/15132184"><span id="translatedtitle">The 3D model: explaining densification and <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> by using 3D parameter plots.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Picker, Katharina M</p> <p>2004-04-01</p> <p>The aim of the study was to analyze very differently <span class="hlt">deforming</span> materials using 3D parameter plots and consequently to gain deeper insights into the densification and <span class="hlt">deformation</span> process described with the 3D model in order to define an ideal tableting excipient. The excipients used were dicalcium phosphate dihydrate (DCPD), sodium chloride (NaCl), microcrystalline cellulose (MCC), xylitol, mannitol, alpha-lactose monohydrate, maltose, hydroxypropyl methylcellulose (HPMC), sodium carboxymethylcellulose (NaCMC), cellulose acetate (CAC), maize starch, potato starch, pregelatinized starch, and maltodextrine. All of the materials were tableted to graded maximum relative densities (rhorel, max) using an eccentric tableting machine. The data which resulted, namely force, displacement, and time, were analyzed by the application of 3D modeling. Different particle size fractions of DCPD, CAC, and MCC were analyzed in addition. Brittle <span class="hlt">deforming</span> materials such as DCPD exhibited a completely different 3D parameter plot, with low time plasticity, d, and low pressure plasticity, e, and a strong decrease in omega values when densification increased, in contrast to the plastically <span class="hlt">deforming</span> MCC, which had much higher d, e, and omega values. e and omega values changed only slightly when densification increased for MCC. NaCl showed less of a decrease in omega values than DCPD did, and the d and e values were between those of MCC and DCPD. The sugar alcohols, xylitol and mannitol, behaved in a similar fashion to sodium chloride. This is also valid for the crystalline sugars, alpha-lactose monohydrate, and maltose. However, the sugars are more brittle than the sugar alcohols. The cellulose derivatives, HPMC, NaCMC, and CAC, are as plastic as MCC, however, their elasticity depends on substitution indicated by lower (more elastic) or higher (less elastic) omega values. The native starches, maize starch and potato starch, are very elastic, and pregelatinized starch and maltodextrine are</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012NatSR...2E.371C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012NatSR...2E.371C"><span id="translatedtitle">Competing <span class="hlt">activation</span> <span class="hlt">mechanisms</span> in epidemics on networks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Castellano, Claudio; Pastor-Satorras, Romualdo</p> <p>2012-04-01</p> <p>In contrast to previous common wisdom that epidemic <span class="hlt">activity</span> in heterogeneous networks is dominated by the hubs with the largest number of connections, recent research has pointed out the role that the innermost, dense core of the network plays in sustaining epidemic processes. Here we show that the <span class="hlt">mechanism</span> responsible of spreading depends on the nature of the process. Epidemics with a transient state are boosted by the innermost core. Contrarily, epidemics allowing a steady state present a dual scenario, where either the hub independently sustains <span class="hlt">activity</span> and propagates it to the rest of the system, or, alternatively, the innermost network core collectively turns into the <span class="hlt">active</span> state, maintaining it globally. In uncorrelated networks the former <span class="hlt">mechanism</span> dominates if the degree distribution decays with an exponent larger than 5/2, and the latter otherwise. Topological correlations, rife in real networks, may perturb this picture, mixing the role of both <span class="hlt">mechanisms</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813561G&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..1813561G&link_type=ABSTRACT"><span id="translatedtitle">10Be surface exposure dating reveals strong <span class="hlt">active</span> <span class="hlt">deformation</span> in the central Andean backarc interior</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>García Morabito, Ezequiel; Terrizzano, Carla; Zech, Roland; Willett, Sean; Yamin, Marcela; Haghipour, Negar; Wuethrich, Lorenz; Christl, Marcus; María Cortes, José; Ramos, Victor</p> <p>2016-04-01</p> <p>Understanding the <span class="hlt">deformation</span> associated with <span class="hlt">active</span> thrust wedges is essential to evaluate seismic hazard. How is <span class="hlt">active</span> faulting distributed throughout the wedge, and how much <span class="hlt">deformation</span> is taken up by individual structures? We address these questions for our study region, the central Andean backarc of Argentina. We combined a structural and geomorphological approach with surface exposure dating (10Be) of alluvial fans and strath terraces in two key localities at ~32° S: the Cerro Salinas, located in the <span class="hlt">active</span> orogenic front of the Precordillera, and the Barreal block in the interior of the Andean mountain range. We analysed 22 surface samples and 6 depth profiles. At the thrust front, the oldest terrace (T1) yields an age of 100-130 ka, the intermediate terrace (T2) between 40-95 ka, and the youngest terrace (T3) an age of ~20 ka. In the Andean interior, T1´ dates to 117-146 ka, T2´ to ~70 ka, and T3´ to ~20 ka, all calculations assuming negligible erosion and using the scaling scheme for spallation based on Lal 1991, Stone 2000. Vertical slip rates of fault offsets are 0.3-0.5 mm/yr and of 0.6-1.2 mm/yr at the thrust front and in the Andean interior, respectively. Our results highlight: i) fault <span class="hlt">activity</span> related to the growth of the Andean orogenic wedge is not only limited to a narrow thrust front zone. Internal structures have been <span class="hlt">active</span> during the last 150 ka, ii) <span class="hlt">deformation</span> rates in the Andean interior are comparable or even higher that those estimated and reported along the emerging thrust front, iii) distribution of <span class="hlt">active</span> faulting seems to account for unsteady state conditions, and iv) seismic hazards may be more relevant in the internal parts of the Andean orogen than assumed so far. References Lal, D., 1991: Cosmic ray labeling of erosion surfaces: In situ nuclide production rates and erosion models. Earth and Planetary Science Letters 104: 424-439. Stone, J.O., 2000: Air pressure and cosmogenic isotope production. Journal of Geophysical</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRF..120..730J&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015JGRF..120..730J&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Active</span> salt <span class="hlt">deformation</span> and rapid, transient incision along the Colorado River near Moab, Utah</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jochems, Andrew P.; Pederson, Joel L.</p> <p>2015-04-01</p> <p>In certain settings, erosion is driven by and balanced with tectonic uplift, but the evolution of many landscapes is dominated by other factors such as geologic substrate, drainage history, and transient incision. The Colorado Plateau is an example where these controls are debated and where salt <span class="hlt">deformation</span> is hypothesized to be locally <span class="hlt">active</span> and driven by differential unloading, although this is unconfirmed and unquantified in most places. We use luminescence-dated Colorado River terraces upstream of Moab, Utah, to quantify rates of salt-driven subsidence and uplift at the local scale. <span class="hlt">Active</span> <span class="hlt">deformation</span> in the study area is also supported by patterns of concavity along tributary drainages crossing salt structures. Subsidence in Professor Valley at a time-averaged rate of ~500 m/Myr (meters/million years) is superimposed upon rapid bedrock incision rates that increase from ~600 to ~900 m/Myr upstream through the study area. Such high rates are unexpected given the absence of sources of regional tectonic uplift here. Instead, the incision rate pattern across the greater area is consistent with a transient signal, perhaps still from ancient drainage integration through Grand Canyon far downstream, and then amplified by unloading at both the broad regional scale and at the local canyon scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3619532','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3619532"><span id="translatedtitle">Fracture of ECAP-<span class="hlt">deformed</span> iron and the role of extrinsic toughening <span class="hlt">mechanisms</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Hohenwarter, A.; Pippan, R.</p> <p>2013-01-01</p> <p>The fracture behaviour of pure iron <span class="hlt">deformed</span> by equal-channel angular pressing via route A was examined. The fracture toughness was determined for different specimen orientations and measured in terms of the critical plane strain fracture toughness, KIC, the critical J integral, JIC, and the crack opening displacement for crack initiation, CODi. The results demonstrate that the crack plane orientation has a pronounced effect on the fracture toughness. Different crack plane orientations lead to either crack deflection or delamination, resulting in increased fracture resistance in comparison to one remarkably weak specimen orientation. The relation between the microstructure typical for the applied <span class="hlt">deformation</span> route and the enormous differences in the fracture toughness depending on the crack plane orientation will be analyzed in this paper. PMID:23645995</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010Litho.120...30W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010Litho.120...30W"><span id="translatedtitle">A review of water contents and ductile <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> of olivine: Implications for the lithosphere-asthenosphere boundary of continents</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Qin</p> <p>2010-11-01</p> <p>Water plays an important role in the ductile <span class="hlt">deformation</span> and evolution of the upper mantle. Water contents of natural olivine from 240 samples reveal a wide variation of 0-170 ppm H 2O, suggesting heterogeneous water distribution in the continental upper mantle. The average water contents (17 ± 13 ppm H 2O) in kimberlite nodules provide the best estimation of water concentrations in olivine in the lithosphere beneath cratons. The very low water contents (7 ± 9 ppm H 2O) of olivine from basalt xenoliths are caused by significant hydrogen loss during transport, while the high values (44 ± 34 ppm H 2O) in olivine megacrysts from kimberlites reflect restricted fluid-rich conditions in the upper mantle. To compare <span class="hlt">deformation</span> in different tectonic environments, the western Superior Province (Canada), the Dabie Mountains and the North Jiangsu basin (China) are selected to represent an Archean craton, an orogenic belt and a rift basin, respectively. Using recent flow laws of olivine, <span class="hlt">deformation</span> maps of dry and wet olivine are constructed under P- T conditions of the three tectonic units and in a continental subduction zone characterized by P = 6.28 GPa and T = 900 °C. For dry olivine, diffusion creep is the dominant <span class="hlt">mechanism</span> in all the cases, which is contrary to the widely observed crystal preferred orientation of olivine in peridotites and seismic anisotropy observations. For wet olivine, only a small amount of water (50 H/10 6 Si) can remarkably decrease the stress of dislocation creep and increase contribution of dislocation creep to the <span class="hlt">deformation</span> of olivine. The strain rate profiles of olivine indicate a transition from dislocation creep to diffusion creep at a depth of ˜ 220 km, which can be related with the Lehmann discontinuity characterized by a rapid decrease in seismic anisotropy. However, the pressure-induced fabric transition from [100] slip to [001] slip may be responsible for the Lehmann discontinuity in subduction zones. Therefore rheology of the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFM.T23I..02M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFM.T23I..02M"><span id="translatedtitle"><span class="hlt">Active</span> <span class="hlt">deformation</span> along the Andaman-Nicobar subduction zone from seismic reflection studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moeremans, R. E.; Singh, S. C.</p> <p>2013-12-01</p> <p>The Andaman-Sumatra subduction zone is one of the most seismically <span class="hlt">active</span> regions on Earth and is a prime example of oblique subduction. It is the result of the oblique convergence between the downgoing Indo-Australian and the overriding Eurasian plates, leading to slip partitioning into a trench-normal thrust component along the plate interface and a trench-subparallel strike-slip component along a sliver fault. The direction of convergence is 90° with respect to the trench near Java, reduces to 45° off of northern Sumatra, and becomes almost parallel to the trench along the Andaman-Nicobar portion of the subduction. Rates of subduction vary from 63 mm/yr off of Java, 50 mm/yr near Nias Island, 45 mm/yr northwest of Sumatra, and 39 mm/yr near the Andaman Islands. After the great December 2004 earthquake, the Sumatran section of the subduction zone was heavily investigated using marine geophysical studies, but the <span class="hlt">deformation</span> processes in the Andaman-Nicobar region remain poorly understood due to the lack of data. Here, we present seismic reflection profiles from the Andaman-Nicobar region that cover the <span class="hlt">deformation</span> front, the forearc high, and the forearc basin. We find that the presence of thick (> 3 s TWT) sediments lead to slip taking place predominantly along landward vergent frontal faults. The frontal fault vergence changes to seaward due to the thinning (< 2 s TWT) of the sediments in the region where the Ninetyeast ridge subducts. The presence of a thick (> 3 s TWT) 20 km-long unit of undeformed sediments, possibly resulting from the landward vergence of the frontal thrusts, suggests that ~40 km of the Ninetyeast ridge has subducted beneath the Andaman forearc. The forearc is widest between the Andaman and Nicobar Islands, likely due to the subduction of thick sediments. The forearc basin is bounded in the west by a series of backthrusts and is underlain by a continental crust, which was once a part of the Malay Peninsula. The forearc basin is crescent</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002REDS..157...85F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002REDS..157...85F"><span id="translatedtitle">Heterogeneous <span class="hlt">deformation</span> and <span class="hlt">mechanical</span> strength of materials - Approach to the theoretical strength</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fujita, H.; Fujita, N.</p> <p>2002-01-01</p> <p>Grain size in polycrystalline materials was changed from larger than phi 10 mum to smaller than phi 10 nm, and the effects of both grain size and strain rate on the strength has been investigated from a view point of heterogeneous <span class="hlt">deformation</span>. Grains of phi10 nm or less in size were obtained by crystallization of amorphous alloys. The experimental results are summarized as follows: (a) Heterogeneous <span class="hlt">deformation</span> is effectively suppressed when grain size decreases smaller than about phi0.1 mum. As a result, the strength remarkably increases in this grain size range, and takes the maximum value when grains of phi10 nm in size are homogeneously formed, (b) When grain size becomes smaller than phi10 nm, those ultrafine grains are embedded into the amorphous matrix, and the strength decreases with increasing volume fraction of amorphous phase. (c) Heterogeneous <span class="hlt">deformation</span> is also effectively suppressed by increasing strain rate in general as well as decreasing grain size. The maximum strength obtained experimentally is compared with the theoretical strengths estimated under various conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016RuPhJ..59..397R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016RuPhJ..59..397R&link_type=ABSTRACT"><span id="translatedtitle">Structural Evolution and <span class="hlt">Mechanical</span> Properties of a VT22 Titanium Alloy Under High-Temperature <span class="hlt">Deformation</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ratochka, I. V.; Mishin, I. P.; Lykova, O. N.; Naydenkin, E. V.; Varlamova, N. V.</p> <p>2016-07-01</p> <p>The special features inherent in the development of high-temperature <span class="hlt">deformation</span> and structural evolution in materials are investigated, using a VT22 titanium alloy of the transition class (Ti - 4.74 mass% Al - 5.57 mass% Mo - 5.04 mass% V) subjected to helical rolling + aging as an example. This treatment is found to give rise to an intragrain fine acicular martensite structure with fine inclusions of α-phase particles of size ~1 μm. It is shown that in the alloy undergoing plastic <span class="hlt">deformation</span> at temperatures approaching the polymorphic transformation temperature, the elongation to failure is in excess of 300%. The high plasticity of the alloy in the conditions considered is likely to be due to vigorous development of phase transformations and intensification of diffusion-controlled processes, including the effects of the evolution of the dislocation structure, growth of subgrains, and formation of new grains in the bulk of the pre-existing ones during plastic <span class="hlt">deformation</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFM.T22A..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFM.T22A..02W"><span id="translatedtitle">Location and <span class="hlt">mechanism</span> of the 1933 Diexi earthquake and its association with the regional tectonic <span class="hlt">deformation</span> prior to the 2008 Wenchuan earthquake</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, K.; Shen, Z.</p> <p>2010-12-01</p> <p>The east margin of the Tibetan plateau is composed of the Longmenshan and Minjiang-Huya fault systems, which are tectonically <span class="hlt">active</span> and produced the 1933 M7.5 Diexi, 1976 M7.2 Songpan doublelet, and 2008 M7.9 Wenchuan earthquakes. Among all the large events the 1933 Diexi earthquake is the least known, and its location and <span class="hlt">mechanism</span>, despite of the importance in understanding the regional tectonic process and assessing the seismic hazards, have been subject to controversy. We collect worldwide seismic records of this earthquake, among which some polarities of the first arrival phases were picked, and use the data to relocate this earthquake and obtain the fault plane solution. The relocated epicenter is at (31.9°E, 103.6°N) and one of the nodal planes trends NNW, with the azimuth ranging N5~30°W. Taking this as the rupture plane of the Diexi earthquake, we conclude that the seismogenic structure was the southern segment of the Minjiang fault, which was dominated mainly by sinistral slip with a minor thrust component. Present day GPS velocity profile across the Minshan Mountains indicates that the Huya fault absorbs ~2 mm/yr crustal shortening, associated with the rapid uplift of the Minshan Mountains since Quaternary. A discrepancy between the focal <span class="hlt">mechanism</span> solution of the 1933 Diexi earthquake and the GPS determined present sense of motion across the Minjiang fault may be attributed to the crustal <span class="hlt">deformation</span> processes of the Longmenshan and Minjiang-Huya fault systems and their earthquake cycles, particularly the role that the Longmen shan fault system played in altering the regional <span class="hlt">deformation</span> field late into the earthquake cycle prior to the 2008 great Wenchuan earthquake. We are using a visco-elastic FEM code to simulate the process taking into account of the layering and lateral change of the crustal and mantle materials. A 3-D evolution of the <span class="hlt">deformation</span> field will be evaluated, and its temporal change due to crustal and mantle rheology across the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcASn..56..378F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcASn..56..378F"><span id="translatedtitle">Research on the Calculated Methods of <span class="hlt">Active</span> Control Value for Antenna Panel <span class="hlt">Deformations</span> under Gravity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fu, L.; Zhong, W. Y.; Qiao, H. H.; Liu, G. X.; Qian, H. L.</p> <p>2015-07-01</p> <p>The methods of ideal reflector surface, two-parameter, five-parameter, and six-parameter best-fit paraboloid are presented in this paper. Based on these methods, the adjustment values of gravity <span class="hlt">deformations</span> are calculated for the main reflector of large-scale Cassegrain antenna. Accordingly, the positions of subreflector are corrected, and the effects of offset-focus on electric performance are also analyzed. Taking Shanghai 65 m antenna as a research object, the adjustment values of actuator and hexapod, the accuracy of the main reflector surface, and the pointing error after offsetting the focus are contrasted. As a result, the method of six-parameter best-fit paraboloid is ideal to calculate <span class="hlt">active</span> control value for antenna panels after the effects of feed defocus have been adjusted and modified. The results offer data for the <span class="hlt">active</span> control of antenna.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.T13C2393H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.T13C2393H"><span id="translatedtitle"><span class="hlt">Mechanical</span> Modeling of Near-Fault <span class="hlt">Deformation</span> Within the Dragon's Back Pressure Ridge, San Andreas Fault, Carrizo Plain, California</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hilley, G. E.; Arrowsmith, R.</p> <p>2011-12-01</p> <p> cases in which the SAF fault friction is low, and the contrast in frictional properties between the simulated North American and Pacific Plate sediments is high. In these cases, the overall dimensions and rock uplift rates predicted by the simulations are, to first order, consistent with values measured or inferred based on field observations. Our results provide a <span class="hlt">mechanically</span> plausible scenario to supplement the geometric explanation previously posed for this specific feature, and indicate that this type of numerical modeling may provide a useful basis for forming a mechanistic understanding these near-fault <span class="hlt">deformation</span> features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006Tectp.427...15R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006Tectp.427...15R"><span id="translatedtitle">Quartz <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> during Barrovian metamorphism: Implications from crystallographic orientation of different generations of quartz in pelites</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rahimi-Chakdel, A.; Boyle, A. P.; Prior, D. J.</p> <p>2006-12-01</p> <p>The behaviour of quartz during metamorphism is studied based on two case studies from the Barrovian terrains of Sulitjelma in arctic Scandinavia and Loch Tay in the Central Highlands Dalradian of Scotland. Both terrains preserve evidence for metamorphism in pelites involving nucleation and growth of garnet at different times in the <span class="hlt">deformation</span> history. Data are presented on the size, shape and crystallographic orientation of quartz preserved as inclusions in garnet and as grains in the surrounding matrix. While quartz-grains remain small and dispersed between mica grains, <span class="hlt">deformation</span> appears to be dominated by grain-boundary sliding accommodated by dissolution-precipitation. At amphibolite facies, textural coarsening occurs by dissolution of small quartz grains and growth of larger quartz grains, coupled with segregation of quartz from mica. As a result, quartz <span class="hlt">deforms</span> by dislocation creep, developing crystallographic preferred orientations (CPO) consistent with both coaxial and non-coaxial strain. Quartz CPOs with <0001> axes lying parallel to foliation and stretching direction are commonly developed, and best explained by <span class="hlt">mechanical</span> rotation of inequant (detrital?) quartz grains. There is no evidence for selective entrapment of quartz inclusions in garnet on the basis of quartz crystallographic orientation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......100B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......100B"><span id="translatedtitle">Characterization Of High-Stroke High-Aspect Ratio Micro Electro <span class="hlt">Mechanical</span> Systems <span class="hlt">Deformable</span> Mirrors For Adaptive Optics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bouchti, Mohamed Amine</p> <p></p> <p>Adaptive optics MEMS <span class="hlt">deformable</span> mirror, in conjunction with Shack Hartman wave front sensor and real-time controller, is capable of correcting time-varying aberrations in imaging applications through manipulating its mirror surface. Adaptive optics systems in astronomy for next generation large telescopes (30 meter primary mirrors) require a high stroke of 10microm of <span class="hlt">mechanical</span> displacement. This required stroke would be achieved by MEMS <span class="hlt">deformable</span> mirrors fabricated with high aspect ratio techniques. This thesis will review the designs of various types of high aspect actuators consisting of folded springs with rectangular and circular membranes as well as X-beam actuators. Finite element analysis (FEA) simulations of these designs have shown the ability of each design to achieve a stroke of approximately 9.4 microm. Also, FEA simulations proved that the X-beam actuators provide the best spring support while preventing tilting. In addition, this thesis will discuss device characterization and voltage vs. displacement test results for the high aspect ratio gold MEMS 16 x 16 X-beam actuators <span class="hlt">deformable</span> mirror that has been bonded and packaged. The results have shown that the device is capable of achieving approximately 5.5 microm in individual actuator testing and 7microm in dual actuator testing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1236578-temperature-dependent-phase-specific-deformation-mechanisms-directionally-solidified-nial-cr-mo-lamellar-composite','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1236578-temperature-dependent-phase-specific-deformation-mechanisms-directionally-solidified-nial-cr-mo-lamellar-composite"><span id="translatedtitle">Temperature-dependent phase-specific <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in a directionally solidified NiAl-Cr(Mo) lamellar composite</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Yu, Dunji; An, Ke; Chen, Xu; Bei, Hongbin</p> <p>2015-10-09</p> <p>Phase-specific thermal expansion and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> behaviors of a directionally solidified NiAl–Cr(Mo) lamellar in situ composite were investigated by using real-time in situ neutron diffraction during compression at elevated temperatures up to 800 °C. Tensile and compressive thermal residual stresses were found to exist in the NiAl phase and Crss (solid solution) phase, respectively. Then, based on the evolution of lattice spacings and phase stresses, the phase-specific <span class="hlt">deformation</span> behavior was analyzed qualitatively and quantitatively. Moreover, estimates of phase stresses were derived by Hooke's law on the basis of a simple method for the determination of stress-free lattice spacing in inmore » situ composites. During compressive loading, the NiAl phase yields earlier than the Crss phase. The Crss phase carries much higher stress than the NiAl phase, and displays consistent strain hardening at all temperatures. The NiAl phase exhibits strain hardening at relatively low temperatures and softening at high temperatures. During unloading, the NiAl phase yields in tension whereas the Crss phase unloads elastically. Additionally, post-test microstructural observations show phase-through cracks at room temperature, micro cracks along phase interfaces at 600 °C and intact lamellae kinks at 800 °C, which is due to the increasing <span class="hlt">deformability</span> of both phases as temperature rises.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1236578','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1236578"><span id="translatedtitle">Temperature-dependent phase-specific <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> in a directionally solidified NiAl-Cr(Mo) lamellar composite</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, Dunji; An, Ke; Chen, Xu; Bei, Hongbin</p> <p>2015-10-09</p> <p>Phase-specific thermal expansion and <span class="hlt">mechanical</span> <span class="hlt">deformation</span> behaviors of a directionally solidified NiAl–Cr(Mo) lamellar in situ composite were investigated by using real-time in situ neutron diffraction during compression at elevated temperatures up to 800 °C. Tensile and compressive thermal residual stresses were found to exist in the NiAl phase and Crss (solid solution) phase, respectively. Then, based on the evolution of lattice spacings and phase stresses, the phase-specific <span class="hlt">deformation</span> behavior was analyzed qualitatively and quantitatively. Moreover, estimates of phase stresses were derived by Hooke's law on the basis of a simple method for the determination of stress-free lattice spacing in in situ composites. During compressive loading, the NiAl phase yields earlier than the Crss phase. The Crss phase carries much higher stress than the NiAl phase, and displays consistent strain hardening at all temperatures. The NiAl phase exhibits strain hardening at relatively low temperatures and softening at high temperatures. During unloading, the NiAl phase yields in tension whereas the Crss phase unloads elastically. Additionally, post-test microstructural observations show phase-through cracks at room temperature, micro cracks along phase interfaces at 600 °C and intact lamellae kinks at 800 °C, which is due to the increasing <span class="hlt">deformability</span> of both phases as temperature rises.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5808I&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5808I&link_type=ABSTRACT"><span id="translatedtitle">The interplay between <span class="hlt">deformation</span> and volcanic <span class="hlt">activity</span>: new data from the central sector of the Campi Flegrei caldera</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Isaia, Roberto; Sabatino, Ciarcia; Enrico, Iannuzzi; Ernesto, Prinzi; D'Assisi, Tramparulo Francesco; Stefano, Vitale</p> <p>2016-04-01</p> <p>The new excavation of a tunnel in the central sector of the Campi Flegrei caldera allowed us to collect new stratigraphic and structural data shedding light on the volcano-tectonic evolution of the last 10 ka. The analyzed sequences are composed by an alternation of volcanic, lacustrine, fluvial and marine sediments hosting several <span class="hlt">deformation</span> structures such as faults, sedimentary dykes and fractures. A review of available well log togheter with the new data were used to perform a 3D reconstruction of paleo-surfaces resulted after the main volcanic and <span class="hlt">deformation</span> episodes. Results show as the paleo-morphology was strictly controlled by faults and fractures that formed meso-scale channels and depressions subsequently filled by tephra and volcanoclastic sediments. The measured structures indicate an extensional <span class="hlt">deformation</span> accompanying the ground uplift occurred in various stages of the caldera evolution. Stratigraphic relationships between structures and volcanic deposits further constrain the timing of the <span class="hlt">deformation</span> phases. Presently an unrest phase of the Campi Flegrei caldera is marked by variations of different parameters such as ground <span class="hlt">deformation</span> <span class="hlt">activities</span> well recorded by GPS data, topographic leveling and satellite surveys. The results of this study provide further insight into the long term <span class="hlt">deformation</span> pattern of the caldera and provide a key to interpret the ground <span class="hlt">deformation</span> scenarios accompanying a possible resumption of volcanism.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016CRPhy..17..485P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016CRPhy..17..485P"><span id="translatedtitle">A versatile lab-on-chip test platform to characterize elementary <span class="hlt">deformation</span> <span class="hlt">mechanisms</span> and electromechanical couplings in nanoscopic objects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pardoen, Thomas; Colla, Marie-Sthéphane; Idrissi, Hosni; Amin-Ahmadi, Behnam; Wang, Binjie; Schryvers, Dominique; Bhaskar, Umesh K.; Raskin, Jean-Pierre</p> <p>2016-03-01</p> <p>A nanomechanical on-chip test platform has recently been developed to <span class="hlt">deform</span> under a variety of loading conditions freestanding thin films, ribbons and nanowires involving submicron dimensions. The lab-on-chip involves thousands of elementary test structures from which the elastic modulus, strength, strain hardening, fracture, creep properties can be extracted. The technique is amenable to in situ transmission electron microscopy (TEM) investigations to unravel the fundamental underlying <span class="hlt">deformation</span> and fracture <span class="hlt">mechanisms</span> that often lead to size-dependent effects in small-scale samples. The method allows addressing electrical and magnetic couplings as well in order to evaluate the impact of large <span class="hlt">mechanical</span> stress levels on different solid-state physics phenomena. We had the chance to present this technique in details to Jacques Friedel in 2012 who, unsurprisingly, made a series of critical and very relevant suggestions. In the spirit of his legacy, the paper will address both <span class="hlt">mechanics</span> of materials related phenomena and couplings with solids state physics issues. xml:lang="fr"</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JNuM..467....9C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JNuM..467....9C"><span id="translatedtitle">The role of stress-state on the <span class="hlt">deformation</span> and fracture <span class="hlt">mechanism</span> of hydrided and non-hydrided Zircaloy-4</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cockeram, B. V.; Hollenbeck, J. L.</p> <p>2015-12-01</p> <p>Zircaloy-4 was tested at room-temperature over a range of hydrogen content between 10 and 200 ppm, and stress-states between a triaxiality of -0.23 and 0.9. Triaxiality (η) is defined as the ratio of hydrostatic stress to von Mises stress and was controlled through use of select <span class="hlt">mechanical</span> test specimen designs. Testing of smooth and notched tensile specimens (η = 0.33 to 0.9) results in an increase in the stress to initiate plastic <span class="hlt">deformation</span> and a decrease in strain to failure at higher values of η. Increases in triaxiality are shown to have a more significant effect on reducing the strain to failure when the material is hydrided. Increases in strain to failure are observed at lower values of triaxiality for dual keyhole specimens (η = 0.1) and compression specimens (η = -0.17 to -0.23), with hydrided material showing much less decrement in strain to failure at these lower triaxialities. Examinations of microstructure are used to show that a change in <span class="hlt">mechanism</span> for <span class="hlt">deformation</span> and fracture with triaxiality can explain these differences in <span class="hlt">mechanical</span> behavior and a model is developed to describe the observed changes in strain to failure with stress-state.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22488899','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22488899"><span id="translatedtitle">Approximation solution of Schrodinger equation for Q-<span class="hlt">deformed</span> Rosen-Morse using supersymmetry quantum <span class="hlt">mechanics</span> (SUSY QM)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Alemgadmi, Khaled I. K. Suparmi; Cari; Deta, U. A.</p> <p>2015-09-30</p> <p>The approximate analytical solution of Schrodinger equation for Q-<span class="hlt">Deformed</span> Rosen-Morse potential was investigated using Supersymmetry Quantum <span class="hlt">Mechanics</span> (SUSY QM) method. The approximate bound state energy is given in the closed form and the corresponding approximate wave function for arbitrary l-state given for ground state wave function. The first excited state obtained using upper operator and ground state wave function. The special case is given for the ground state in various number of q. The existence of Rosen-Morse potential reduce energy spectra of system. The larger value of q, the smaller energy spectra of system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4786634','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4786634"><span id="translatedtitle">Molecular <span class="hlt">mechanisms</span> regulating NLRP3 inflammasome <span class="hlt">activation</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Jo, Eun-Kyeong; Kim, Jin Kyung; Shin, Dong-Min; Sasakawa, Chihiro</p> <p>2016-01-01</p> <p>Inflammasomes are multi-protein signaling complexes that trigger the <span class="hlt">activation</span> of inflammatory caspases and the maturation of interleukin-1β. Among various inflammasome complexes, the NLRP3 inflammasome is best characterized and has been linked with various human autoinflammatory and autoimmune diseases. Thus, the NLRP3 inflammasome may be a promising target for anti-inflammatory therapies. In this review, we summarize the current understanding of the <span class="hlt">mechanisms</span> by which the NLRP3 inflammasome is <span class="hlt">activated</span> in the cytosol. We also describe the binding partners of NLRP3 inflammasome complexes <span class="hlt">activating</span> or inhibiting the inflammasome assembly. Our knowledge of the <span class="hlt">mechanisms</span> regulating NLRP3 inflammasome signaling and how these influence inflammatory responses offers further insight into potential therapeutic strategies to treat inflammatory diseases associated with dysregulation of the NLRP3 inflammasome. PMID:26549800</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21804763','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21804763"><span id="translatedtitle"><span class="hlt">Mechanisms</span> of Cell Propulsion by <span class="hlt">Active</span> Stresses.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carlsson, A E</p> <p>2011-07-01</p> <p>The <span class="hlt">mechanisms</span> by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored using a simplified model of the cytoskeleton as a viscous gel containing <span class="hlt">active</span> stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of <span class="hlt">active</span> stress and cell-substrate friction. It is found that 1) the cell velocity is given by a function that quantifies the asymmetry of the <span class="hlt">active</span>-stress distribution, 2) gradients in cell-substrate friction can induce motion even when the <span class="hlt">active</span> stresses are symmetrically distributed, 3) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell, and 4) the cell velocity depends biphasically on the cell-substrate adhesion strength if <span class="hlt">active</span> stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed. PMID:21804763</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3146262','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3146262"><span id="translatedtitle"><span class="hlt">Mechanisms</span> of Cell Propulsion by <span class="hlt">Active</span> Stresses</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Carlsson, A. E.</p> <p>2011-01-01</p> <p>The <span class="hlt">mechanisms</span> by which cytoskeletal flows and cell-substrate interactions interact to generate cell motion are explored using a simplified model of the cytoskeleton as a viscous gel containing <span class="hlt">active</span> stresses. This model yields explicit general results relating cell speed and traction forces to the distributions of <span class="hlt">active</span> stress and cell-substrate friction. It is found that 1) the cell velocity is given by a function that quantifies the asymmetry of the <span class="hlt">active</span>-stress distribution, 2) gradients in cell-substrate friction can induce motion even when the <span class="hlt">active</span> stresses are symmetrically distributed, 3) the traction-force dipole is enhanced by protrusive stresses near the cell edges or contractile stresses near the center of the cell, and 4) the cell velocity depends biphasically on the cell-substrate adhesion strength if <span class="hlt">active</span> stress is enhanced by adhesion. Specific experimental tests of the calculated dependences are proposed. PMID:21804763</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT........74M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT........74M"><span id="translatedtitle">The role of microstructure on <span class="hlt">deformation</span> and damage <span class="hlt">mechanisms</span> in a Nickel-based superalloy at elevated temperatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Maciejewski, Kimberly E.</p> <p></p> <p> introduced by considering the mobility limit in the tangential direction leading to strain incompatibility and failure. This limit is diminished by environmental effects which are introduced as a dynamic embrittlement process that hinders grain boundary mobility due to oxygen diffusion. The concepts described herein indicate that implementation of the cohesive zone model requires the knowledge of the grain boundary external and internal <span class="hlt">deformation</span> fields. The external field is generated by developing and coupling two continuum constitutive models including (i) a microstructure-explicit coarse scale crystal plasticity model with strength provided by tertiary and secondary gamma' precipitates. This scale is appropriate for the representation of the continuum region at the immediate crack tip, and (ii) a macroscopic internal state variable model for the purpose of modeling the response of the far field region located several grains away from the crack path. The hardening contributions of the gamma' precipitates consider dislocation/precipitate interactions in terms of gamma' particles shearing and/or Orowan by-passing <span class="hlt">mechanisms</span>. The material parameters for these models are obtained from results of low cycle fatigue tests which were performed at three temperatures; 650, 704 and 760°C. Furthermore, a series of microstructure controlled experiments were carried out in order to develop and validate the microstructure dependency feature of the continuum constitutive models. The second requirement in the implementation of the cohesive zone model is a grain boundary <span class="hlt">deformation</span> model which has been developed, as described above, on the basis of viscous flow rules of the boundary material. This model is supported by dwell crack growth experiments carried out at the three temperatures mentioned above, in both air and vacuum environments. Results of these tests have identified the frequency range in which the grain boundary cohesive zone model is applicable and also provided data to</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJASE...8..103A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016IJASE...8..103A&link_type=ABSTRACT"><span id="translatedtitle">A simple higher order shear <span class="hlt">deformation</span> theory for <span class="hlt">mechanical</span> beha