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Sample records for 384-well plate format

  1. Reproducibility of Uniform Spheroid Formation in 384-Well Plates: The Effect of Medium Evaporation.

    PubMed

    Das, Viswanath; Fürst, Tomáš; Gurská, Soňa; Džubák, Petr; Hajdúch, Marián

    2016-10-01

    Spheroid cultures of cancer cells reproduce the spatial dimension-induced in vivo tumor traits more effectively than the conventional two-dimensional cell cultures. With growing interest in spheroids for high-throughput screening (HTS) assays, there is an increasing demand for cost-effective miniaturization of reproducible spheroids in microtiter plates (MPs). However, well-to-well variability in spheroid size, shape, and growth is a frequently encountered problem with almost every culture method that has prevented the transfer of spheroids to the HTS platform. This variability partly arises due to increased susceptibility of MPs to edge effects and evaporation-induced changes in the growth of spheroids. In this study, we examined the effect of evaporation on the reproducibility of spheroids of tumor and nontumor cell lines in 384-well plates, and show that culture conditions that prevent evaporation-induced medium loss result in the formation of uniform spheroids across the plate. Additionally, we also present a few technical improvements to increase the scalability of the liquid-overlay spheroid culturing technique in MPs, together with a simple software routine for the quantification of spheroid size. We believe that these cost-effective improvements will aid in further improvement of spheroid cultures for HTS drug discovery.

  2. Microscale 3D collagen cell culture assays in conventional flat-bottom 384-well plates.

    PubMed

    Leung, Brendan M; Moraes, Christopher; Cavnar, Stephen P; Luker, Kathryn E; Luker, Gary D; Takayama, Shuichi

    2015-04-01

    Three-dimensional (3D) culture systems such as cell-laden hydrogels are superior to standard two-dimensional (2D) monolayer cultures for many drug-screening applications. However, their adoption into high-throughput screening (HTS) has been lagging, in part because of the difficulty of incorporating these culture formats into existing robotic liquid handling and imaging infrastructures. Dispensing cell-laden prepolymer solutions into 2D well plates is a potential solution but typically requires large volumes of reagents to avoid evaporation during polymerization, which (1) increases costs, (2) makes drug penetration variable and (3) complicates imaging. Here we describe a technique to efficiently produce 3D microgels using automated liquid-handling systems and standard, nonpatterned, flat-bottomed, 384-well plates. Sub-millimeter-diameter, cell-laden collagen gels are deposited on the bottom of a ~2.5 mm diameter microwell with no concerns about evaporation or meniscus effects at the edges of wells, using aqueous two-phase system patterning. The microscale cell-laden collagen-gel constructs are readily imaged and readily penetrated by drugs. The cytotoxicity of chemotherapeutics was monitored by bioluminescence and demonstrated that 3D cultures confer chemoresistance as compared with similar 2D cultures. Hence, these data demonstrate the importance of culturing cells in 3D to obtain realistic cellular responses. Overall, this system provides a simple and inexpensive method for integrating 3D culture capability into existing HTS infrastructure. PMID:25510473

  3. Development of resazurin-based assay in 384-well format for high throughput whole cell screening of Trypanosoma brucei rhodesiense strain STIB 900 for the identification of potential anti-trypanosomal agents.

    PubMed

    Lim, Kah Tee; Zahari, Zuriati; Amanah, Azimah; Zainuddin, Zafarina; Adenan, Mohd Ilham

    2016-03-01

    To accelerate the discovery of novel leads for the treatment of Human African Trypanosomiasis (HAT), it is necessary to have a simple, robust and cost-effective assay to identify positive hits by high throughput whole cell screening. Most of the fluorescence assay was made in black plate however in this study the HTS assay developed in 384-well format using clear plate and black plate, for comparison. The HTS assay developed is simple, sensitive, reliable and reproducible in both types of plates. Assay robustness and reproducibility were determined under the optimized conditions in 384-well plate was well tolerated in the HTS assay, including percentage of coefficient of variation (% CV) of 4.68% and 4.74% in clear and black 384-well plate, signal-to-background ratio (S/B) of 12.75 in clear 384-well plate and 12.07 in black 384-well plate, Z' factor of 0.79 and 0.82 in clear 384-well plate and black 384-well plate, respectively and final concentration of 0.30% dimethylsulfoxide (DMSO) in both types of plate. Drug sensitivity was found to be comparable to the reported anti-trypanosomal assay in 96-well format. The reproducibility and sensitivity of this assay make it compliant to automated liquid handler use in HTS applications. PMID:26772786

  4. Development of resazurin-based assay in 384-well format for high throughput whole cell screening of Trypanosoma brucei rhodesiense strain STIB 900 for the identification of potential anti-trypanosomal agents.

    PubMed

    Lim, Kah Tee; Zahari, Zuriati; Amanah, Azimah; Zainuddin, Zafarina; Adenan, Mohd Ilham

    2016-03-01

    To accelerate the discovery of novel leads for the treatment of Human African Trypanosomiasis (HAT), it is necessary to have a simple, robust and cost-effective assay to identify positive hits by high throughput whole cell screening. Most of the fluorescence assay was made in black plate however in this study the HTS assay developed in 384-well format using clear plate and black plate, for comparison. The HTS assay developed is simple, sensitive, reliable and reproducible in both types of plates. Assay robustness and reproducibility were determined under the optimized conditions in 384-well plate was well tolerated in the HTS assay, including percentage of coefficient of variation (% CV) of 4.68% and 4.74% in clear and black 384-well plate, signal-to-background ratio (S/B) of 12.75 in clear 384-well plate and 12.07 in black 384-well plate, Z' factor of 0.79 and 0.82 in clear 384-well plate and black 384-well plate, respectively and final concentration of 0.30% dimethylsulfoxide (DMSO) in both types of plate. Drug sensitivity was found to be comparable to the reported anti-trypanosomal assay in 96-well format. The reproducibility and sensitivity of this assay make it compliant to automated liquid handler use in HTS applications.

  5. Antimicrobial assay optimization and validation for HTS in 384-well format using a bioluminescent E. coli K-12 strain.

    PubMed

    Nybond, Susanna; Karp, Matti; Tammela, Päivi

    2013-07-16

    This report describes the optimization and validation of an antimicrobial assay based on the genetically modified bacterial strain Escherichia coli K-12 (pTetlux1). The use of this particular strain enables an inducible cell-based bioluminescent assay for high-throughput screening (HTS) of antimicrobial agents, which shows a pronounced detection of compounds targeting transcriptional and translational events in protein synthesis. The optimizations in 96-well format led to several improvements in assay conditions, such as reduction of the pre-incubation time before luminescence induction by half. The threshold for DMSO tolerability was concluded to be up to 1%. Assay protocol was further miniaturized into 384-well format and the liquid handling was automated using a robotic workstation. The use of compound pre-plating into 384-well plates as a part of the process was evaluated, and the total assay volume was further downscaled from 50 μl to 30 μl. With this approach, the amount of test compound needed per well was reduced to nanoliter volumes. Using the miniaturized protocol a pilot screen of 2000 known drugs and bioactives was performed. The assay performance was evaluated by calculating known assay quality parameters, the Z' factor having a mean value of 0.8 during the compound library screening indicated an excellent performance. Of the assay positives, 54 compounds showed high inhibitions (60-100%), of which the majority (89%) were known antibacterial agents. Of the actives showing >60% inhibition, 16 compounds were identified as known transcriptional and translational inhibitors. The screening results demonstrated that the miniaturized assay is well suited for identification of antimicrobial compounds in HT screening, and that the assay is specifically sensitive towards bacterial transcription and translation inhibitors.

  6. Gas chromatography fractionation platform featuring parallel flame-ionization detection and continuous high-resolution analyte collection in 384-well plates.

    PubMed

    Jonker, Willem; Clarijs, Bas; de Witte, Susannah L; van Velzen, Martin; de Koning, Sjaak; Schaap, Jaap; Somsen, Govert W; Kool, Jeroen

    2016-09-01

    Gas chromatography (GC) is a superior separation technique for many compounds. However, fractionation of a GC eluate for analyte isolation and/or post-column off-line analysis is not straightforward, and existing platforms are limited in the number of fractions that can be collected. Moreover, aerosol formation may cause serious analyte losses. Previously, our group has developed a platform that resolved these limitations of GC fractionation by post-column infusion of a trap solvent prior to continuous small-volume fraction collection in a 96-wells plate (Pieke et al., 2013 [17]). Still, this GC fractionation set-up lacked a chemical detector for the on-line recording of chromatograms, and the introduction of trap solvent resulted in extensive peak broadening for late-eluting compounds. This paper reports advancements to the fractionation platform allowing flame ionization detection (FID) parallel to high-resolution collection of a full GC chromatograms in up to 384 nanofractions of 7s each. To this end, a post-column split was incorporated which directs part of the eluate towards FID. Furthermore, a solvent heating device was developed for stable delivery of preheated/vaporized trap solvent, which significantly reduced band broadening by post-column infusion. In order to achieve optimal analyte trapping, several solvents were tested at different flow rates. The repeatability of the optimized GC fraction collection process was assessed demonstrating the possibility of up-concentration of isolated analytes by repetitive analyses of the same sample. The feasibility of the improved GC fractionation platform for bioactivity screening of toxic compounds was studied by the analysis of a mixture of test pesticides, which after fractionation were subjected to a post-column acetylcholinesterase (AChE) assay. Fractions showing AChE inhibition could be unambiguously correlated with peaks from the parallel-recorded FID chromatogram. PMID:27485151

  7. Development and Optimization of a Novel 384-Well Anti-Malarial Imaging Assay Validated for High-Throughput Screening

    PubMed Central

    Duffy, Sandra; Avery, Vicky M.

    2012-01-01

    With the increasing occurrence of drug resistance in the malaria parasite, Plasmodium falciparum, there is a great need for new and novel anti-malarial drugs. We have developed a 384-well, high-throughput imaging assay for the detection of new anti-malarial compounds, which was initially validated by screening a marine natural product library, and subsequently used to screen more than 3 million data points from a variety of compound sources. Founded on another fluorescence-based P. falciparum growth inhibition assay, the DNA-intercalating dye 4′,6-diamidino-2-phenylindole, was used to monitor changes in parasite number. Fluorescent images were acquired on the PerkinElmer Opera High Throughput confocal imaging system and analyzed with a spot detection algorithm using the Acapella data processing software. Further optimization of this assay sought to increase throughput, assay stability, and compatibility with our high-throughput screening equipment platforms. The assay typically yielded Z'-factor values of 0.5–0.6, with signal-to-noise ratios of 12. PMID:22232455

  8. LOWLID FORMATION AND PLATE TECTONICS ON EXOPLANETS

    NASA Astrophysics Data System (ADS)

    Stamenkovic, V.; Noack, L.; Breuer, D.

    2009-12-01

    The last years of astronomical observation have opened the doors to a universe filled with extrasolar planets. Detection techniques still only offer the possibility to detect mainly Super-Earths above five Earth masses. But detection techniques do steadily improve and are offering the possibility to detect even smaller planets. The observations show that planets seem to exist in many possible sizes just as the planets and moons of our own solar system do. It is only a natural question to ask if planetary mass has an influence on some key habitability factors such as on plate tectonics, allowing us to test which exoplanets might be more likely habitable than others, and allowing us to understand if plate tectonics on Earth is a stable or a critical, instable process that could easily be perturbed. Here we present results derived from 1D parameterized thermal evolution and 2D/3D computer models, showing how planetary mass influences the propensity of plate tectonics for planets with masses ranging from 0.1 to 10 Earth masses. Lately [2, 3] studied the effect of planetary mass on the ability to break plates and hence initiate plate tectonics - but both derived results contradictory to the other. We think that one of the reasons why both studies [2, 3] are not acceptable in their current form is partly due to an oversimplification. Both treated viscosity only temperature-dependent but neglected the effect pressure has on enlarging the viscosity in the deep mantle. More massive planets have therefore a stronger pressure-viscosity-coupling making convection at high pressures sluggish or even impossible. For planets larger than two Earth masses we observe that a conductive lid (termed low-lid) forms above the core-mantle boundary and thus reduces the effective convective part of the mantle when including a pressure-dependent term into the viscosity laws as shown in [1]. Moreover [2, 3] use time independent steady state models neglecting the fact that plate tectonics is a

  9. Droplet formation under the effect of a flexible nozzle plate.

    PubMed

    Sangplung, S; Liburdy, J A

    2009-09-01

    Droplet formation from a flexible nozzle plate driven by a prescribed-waveform excitation of a piezoelectric is numerically investigated using a computational fluid dynamics (CFD) model with the volume of fluid (VOF) method. The droplet generator with a flexible nozzle plate, which is free to vibrate due to the pressure acting on the plate, is modeled in a CFD computational domain. The CFD analysis includes the fluid-structure interaction between fluid and a flexible plate using large deflection theory. The problem is characterized by the nondimensional variables based on the capillary parameters of time, velocity, and pressure. The CFD model is validated with the experiment results. This study examines the characteristics of the applied waveforms and nozzle plate material properties to change the vibrational characteristics of the nozzle plate. The effect of fluid properties on the droplet formation process is also investigated focusing on surface tension and viscous forces. Increasing the impulse of the piezoelectric can be used to cause a higher droplet velocity and it is shown that the vibration of the nozzle plate has a strong effect on the droplet velocity, shape, and volume. Surface tension has a strong influence on the droplet formation characteristics in contrast to viscous forces. For the combination of a fluid with high surface tension and the most flexible nozzle plate, this system cannot cause the droplet ejected out of the nozzle.

  10. Eastern Indian Ocean microcontinent formation driven by plate motion changes

    NASA Astrophysics Data System (ADS)

    Whittaker, J. M.; Williams, S. E.; Halpin, J. A.; Wild, T. J.; Stilwell, J. D.; Jourdan, F.; Daczko, N. R.

    2016-11-01

    The roles of plate tectonic or mantle dynamic forces in rupturing continental lithosphere remain controversial. Particularly enigmatic is the rifting of microcontinents from mature continental rifted margins, with plume-driven thermal weakening commonly inferred to facilitate calving. However, a role for plate tectonic reorganisations has also been suggested. Here, we show that a combination of plate tectonic reorganisation and plume-driven thermal weakening were required to calve the Batavia and Gulden Draak microcontinents in the Cretaceous Indian Ocean. We reconstruct the evolution of these two microcontinents using constraints from new paleontological samples, 40Ar/39Ar ages, and geophysical data. Calving from India occurred at 101-104 Ma, coinciding with the onset of a dramatic change in Indian plate motion. Critically, Kerguelen plume volcanism does not appear to have directly triggered calving. Rather, it is likely that plume-related thermal weakening of the Indian passive margin preconditioned it for microcontinent formation but calving was triggered by changes in plate tectonic boundary forces.

  11. High Speed Large Format Photon Counting Microchannel Plate Imaging Sensors

    NASA Astrophysics Data System (ADS)

    Siegmund, O.; Ertley, C.; Vallerga, J.; Craven, C.; Popecki, M.; O'Mahony, A.; Minot, M.

    The development of a new class of microchannel plate technology, using atomic layer deposition (ALD) techniques applied to a borosilicate microcapillary array is enabling the implementation of larger, more stable detectors for Astronomy and remote sensing. Sealed tubes with MCPs with SuperGenII, bialkali, GaAs and GaN photocathodes have been developed to cover a wide range of optical/UV sensing applications. Formats of 18mm and 25mm circular, and 50mm (Planacon) and 20cm square have been constructed for uses from night time remote reconnaissance and biological single-molecule fluorescence lifetime imaging microscopy, to large area focal plane imagers for Astronomy, neutron detection and ring imaging Cherenkov detection. The large focal plane areas were previously unattainable, but the new developments in construction of ALD microchannel plates allow implementation of formats of 20cm or more. Continuing developments in ALD microchannel plates offer improved overall sealed tube lifetime and gain stability, and furthermore show reduced levels of radiation induced background. High time resolution astronomical and remote sensing applications can be addressed with microchannel plate based imaging, photon time tagging detector sealed tube schemes. Photon counting imaging readouts for these devices vary from cross strip (XS), cross delay line (XDL), to stripline anodes, and pad arrays depending on the intended application. The XS and XDL readouts have been implemented in formats from 22mm, and 50mm to 20cm. Both use MCP charge signals detected on two orthogonal layers of conductive fingers to encode event X-Y positions. XDL readout uses signal propagation delay to encode positions while XS readout uses charge cloud centroiding. Spatial resolution readout of XS detectors can be better than 20 microns FWHM, with good image linearity while using low gain (<10^6), allowing high local counting rates and longer overall tube lifetime. XS tubes with electronics can encode event

  12. Formation of Plates in Numerical Mantle Convection Models

    NASA Astrophysics Data System (ADS)

    Stein, C.; Hansen, U.

    2001-12-01

    In a threedimensional numerical model we demonstrate that with an appropriate rheology the mantle convection system organizes itself into a state, exhibiting essential features of plate tectonics. While a strongly temperature-dependent viscosity leads to a stagnant lid, mobilization of the surface appears if an additional yield-stress criterion is taken into account. During short periods, parts of the surface move like plates. These periods are interrupted by phases in which a stagnant lid exists. Besides plate-like motion we observe other features like the migration of subduction-zones. Adding further a pressure dependence of the viscosity leads to change from the episodic to a more continuous plate-like behavior. Once plates have formed, the surface moves essentially steady throughout the modelled time. This models evolves into a state displaying extended rigidly moving plates, surrounded by localized areas with high deformation.

  13. Vortex Formation in the Starting Flow of Rotating Low-Aspect-Ratio Plates

    NASA Astrophysics Data System (ADS)

    Devoria, Adam; Ringuette, Matthew

    2010-11-01

    We investigate the unsteady flow of fish fin-like plates accelerating from rest through various angular velocity profiles. The objective is to gain an understanding of the connection among the prescribed kinematics and resulting vortex formation; a relationship which has not currently been thoroughly explored. The root-to-tip flow that is induced by the plate motion is expected to have significant effects on the vortex formation. Additionally, different plate shapes are studied to compare the effects of geometrical changes. The experiments are conducted in a water tank, and the plates have a fixed axis of rotation. Digital particle image velocimetry (DPIV) is used to measure the flow velocity in a symmetry plane through the plates. Vorticity and circulation are subsequently computed and vortices are distinguished from surrounding flow structures using vortex identification schemes. Carefully incorporating these techniques will aid the development of scaling laws to characterize the vortex formation with maximum attainable vortex strength.

  14. The pisiform growth plate is lost in humans and supports a role for Hox in growth plate formation

    PubMed Central

    Kjosness, Kelsey M; Hines, Jasmine E; Lovejoy, C Owen; Reno, Philip L

    2014-01-01

    The human pisiform is a small, nodular, although functionally significant, bone of the wrist. In most other mammals, including apes and Australopithecus afarensis, pisiforms are elongate. An underappreciated fact is that the typical mammalian pisiform forms from two ossification centers. We hypothesize that: (i) the presence of a secondary ossification center in mammalian pisiforms indicates the existence of a growth plate; and (ii) human pisiform reduction results from growth plate loss. To address these hypotheses, we surveyed African ape pisiform ossification and confirmed the presence of a late-forming secondary ossification center in chimpanzees and gorillas. Identification of the initial ossification center occurs substantially earlier in apes relative to humans, raising questions concerning the homology of the human pisiform and the two mammalian ossification centers. Second, we conducted histological and immunohistochemical analyses of pisiform ossification in mice. We confirm the presence of two ossification centers separated by organized columnar and hypertrophic chondrocyte zones. Flattened chondrocytes were highly mitotic, indicating the presence of a growth plate. Hox genes have been proposed to play a fundamental role in growth plate patterning. The existence of a pisiform growth plate presents an interesting test case for the association between Hox expression and growth plate formation, and could explain the severe effects on the pisiform observed in Hoxa11 and Hoxd11 knockout mice. Consistent with this hypothesis, we show that Hoxd11 is expressed adjacent to the pisiform in late-stage embryonic mouse limbs supporting a role for Hox genes in growth plate specification. This raises questions concerning the mechanisms regulating Hox expression in the developing carpus. PMID:25279687

  15. A modified microtiter-plate test for quantification of staphylococcal biofilm formation.

    PubMed

    Stepanovic, S; Vukovic, D; Dakic, I; Savic, B; Svabic-Vlahovic, M

    2000-04-01

    The tube test and the microtiter-plate test are the most frequently used techniques for quantifying biofilm formation, an important indicator for the pathogenicity of staphylococci. The purpose of the present study was to develop a modified microtiter-plate technique for quantification of biofilm formation. This technique involves fixing the bacterial film with methanol, staining with crystal violet, releasing the bound dye with 33% glacial acetic acid, and measuring the optical density (OD) of the solution at 570 nm by using an enzyme immunosorbent assay reader. Biofilm formation of 30 Staphylococcus strains was estimated by the tube test, the standard microtiter-plate test and the modified microtiter-plate test. The modified microtiter-plate test, as a quantitative assay, is superior to the tube test in terms of objectivity and accuracy. It is also superior to the standard microtiter-plate test because it enables indirect measuring of bacteria attached both to the bottom and to the walls of the wells, while in the standard test only the dye bound to the bacteria adhered to the bottom of the wells is spectrophotometrically registered. Highly significant differences between OD values obtained by the standard microtiter-plate test and those obtained by the modified test suggest that large number of bacteria were attached to the walls of the wells. Therefore, the modification of the standard microtiter-plate test by introduction of an additional step of decolorization by acetic acid seems to be a useful improvement of the technique.

  16. Endocytosis of cell surface material mediates cell plate formation during plant cytokinesis.

    PubMed

    Dhonukshe, Pankaj; Baluska, Frantisek; Schlicht, Markus; Hlavacka, Andrej; Samaj, Jozef; Friml, Jirí; Gadella, Theodorus W J

    2006-01-01

    Dividing plant cells perform a remarkable task of building a new cell wall within the cytoplasm in a few minutes. A long-standing paradigm claims that this primordial cell wall, known as the cell plate, is generated by delivery of newly synthesized material from Golgi apparatus-originated secretory vesicles. Here, we show that, in diverse plant species, cell surface material, including plasma membrane proteins, cell wall components, and exogenously applied endocytic tracers, is rapidly delivered to the forming cell plate. Importantly, this occurs even when de novo protein synthesis is blocked. In addition, cytokinesis-specific syntaxin KNOLLE as well as plasma membrane (PM) resident proteins localize to endosomes that fuse to initiate the cell plate. The rate of endocytosis is strongly enhanced during cell plate formation, and its genetic or pharmacological inhibition leads to cytokinesis defects. Our results reveal that endocytic delivery of cell surface material significantly contributes to cell plate formation during plant cytokinesis.

  17. Spray Formation during the Impact of a Flat Plate on Water Surface

    NASA Astrophysics Data System (ADS)

    Wang, An; Duncan, James H.

    2015-11-01

    Spray formation during the impact of a flat plate on a water surface is studied experimentally. The plate is mounted on a two-axis carriage that can slam the plate vertically into the water surface as the carriage moves horizontally along a towing tank. The plate is 122 cm by 38 cm and oriented with adjustable pitch and roll angle. The port (lower) edge of the plate is positioned with a 3-mm gap from one of the tank walls. A laser sheet is created in a plane oriented perpendicular to the axis of the horizontal motion of the carriage. The temporal evolution of the spray within the light sheet is measured with a cinematic laser induced fluorescence technique at a frame rate of 800 Hz. Experiments are performed with a fixed plate trajectory in a vertical plane, undertaken at various speeds. Two types of spray are found when the plate has nonzero pitch and roll angles. The first type is composed of a cloud of high-speed droplets and ligaments generated as the port edge of the plate hits the water surface during the initial impact. The second type is a thin sheet of water that grows from the starboard edge of the plate as it moves below the local water level. The geometrical features of the spray are found to be dramatically affected by the impact velocity. The support of the Office of Naval Research under grant N000141310587 is gratefully acknowledged.

  18. Effect of the substrate orientation on the formation of He-plates in Si

    SciTech Connect

    Vallet, M.; Barbot, J. F.; Declémy, A.; Beaufort, M. F.; Reboh, S.

    2013-11-21

    The effect of the crystalline orientation on the implantation-induced strain/stress and on the formation of He-plates was studied by combining high-resolution X-ray scattering and transmission electron microscopy. The highest strains are obtained in (001)-oriented implanted substrates regardless of the fluence and of the channeling effects. The anisotropic properties of the silicon that generate an anisotropic elastic response of the substrate were taken into account to explain these different values of strain. Upon specific thermal annealing, it is shown that the formation of He-plates occurs only in the (001) habit planes regardless of the orientation of the substrates, non-tilted and tilted (001)-, (110)-, and (111)-substrates. Moreover, the distribution of He-plates in the (001) variants was found to be strongly dependent on the angle of the habit plane with the surface and on the intensity of the implantation-induced strain/stress. The implantation-induced stress thus favors the formation of He-plates in specific planes (of low angle with the surface) forming different defect configurations. The nucleation and growth of He-plates are thus discussed with regard to the implantation-induced stress.

  19. Vortex Formation, Shedding and Energy Harvesting from a Cyber-Physical Pitching Flat Plate

    NASA Astrophysics Data System (ADS)

    Onoue, Kyohei; Breuer, Kenneth

    2014-11-01

    We examine the dynamics and energy harvesting capabilities of an elastically mounted flat plate undergoing large amplitude limit cycle oscillations in a uniform flow. All experiments are performed using a cyber-physical system, wherein the structural inertia, stiffness and damping are numerically simulated using a position-following feedback algorithm. The cyber-physical system also allows for implementation of nonlinear spring and damping coefficients, which control the plate dynamics and subsequent energy harvesting characteristics. Analysis of the plate kinematics and the fluid flow over the plate and in the wake (measured using PIV) are used to understand the interplay between structural motion and vortex formation at the sharp leading and trailing edges of the plate. By varying the structural properties of the system we systematically analyze the formation, strength, stability and separation of the leading edge vortex, as well as the dependence on kinematic parameters and Reynolds number. Connections to previous results on vortex formation time and bluff body aerodynamics are discussed. This research is funded by the Air Force Office of Scientific Research (AFOSR).

  20. HIGHLY SENSITIVE ASSAY FOR ANTICHOLINESTERASE COMPOUNDS USING 96 WELL PLATE FORMAT

    EPA Science Inventory

    The rapid and sensitive detection of organophosphate insecticides using a 96 well plate format is reported. Several features of this assay make it attractive for development as a laboratory-based or field screening assay. Acetylcholinesterase (AChE) was stabilized in a gelati...

  1. Growth plate formation and development in alligator and mouse metapodials: evolutionary and functional implications.

    PubMed

    Reno, Philip L; Horton, Walter E; Elsey, Ruth M; Lovejoy, C Owen

    2007-05-15

    Mammalian metapodials (metacarpals and metatarsals), unlike most long bones, form a single growth plate, and undergo longitudinal growth at only one end. The growth dynamics of non-mammalian tetrapod metapodials have not been systematically examined in order to determine if unidirectional growth is unique to mammals. Here we compare murine metapodial ossification in growth stages that parallel those of embryonic, juvenile and subadult American alligators (Alligator mississippiensis). Safranin O staining was used for qualitative histology, and chondrocyte differentiation and proliferation were assessed via immunohistochemistry for type X collagen and proliferative cell nuclear antigen (PCNA). We establish that growth plates form at both ends of alligator metapodials and are maintained in the subadult. PCNA results show that alligators and mice share common patterns of chondrocyte proliferation during growth plate formation. In addition, while alligators and mice differ initially in the degree of organization and pace of chondrocyte differentiation, these parameters are largely similar in established growth plates. However, the replacement of cartilage by bone is highly irregular throughout growth in the alligator, in contrast to the more uniform process in the mouse. These results indicate that while alligators and mammals share common mechanisms of chondrocyte regulation, they differ substantially in their processes of ossification. Phylogenetic analysis indicates that the direct ossification of one epiphysis and reliance on a single growth plate is a derived character (synapomorphy) in therian mammals and likely indicates an adaptation for erect quadrupedal gait. PMID:17285637

  2. Insight into characteristic features of cartilage growth plate as a physiological template for bone formation.

    PubMed

    Jaroszewicz, Jakub; Kosowska, Anna; Hutmacher, Dietmar; Swieszkowski, Wojciech; Moskalewski, Stanisław

    2016-02-01

    Cartilage growth plate is a natural template from both a biochemical and structural point of view and allows osteoblasts migration, proliferation, differentiation, and ultimately, bone formation. It is evolutionary adjusted to support bone formation within strictly defined spatial framework serving as an interesting model for studying more mechanistically aspects which might be important for specific scaffold-based bone tissue engineering strategies. Surprisingly little is known about the geometric features of this physiological template. To this purpose we analyzed cartilage growth plate from rat, mouse, and human costochondral junction and tibia. High-resolution X-ray tomography showed that pore size in the zone of provisional calcification was within 20 to 30 µm range and in the metaphysis in 35 to 50 µm range. The thickness of calcified longitudinal septa in zone of provisional calcification was 3 to 5 µm and in metaphysis 7 to 12 µm. The porosity varied from 84 to 88%. We observed that numerical values characteristic for cartilage growth plate were not significantly influenced by the species of origin, by the type of bone, or by age. In addition, electron microscopy of calcified fragments of longitudinal septa showed that the calcium aggregates were globular, connected with each other, and formed a shell covering cartilage matrix located within longitudinal septa.

  3. Quantitative comparison between microfluidic and microtiter plate formats for cell-based assays.

    PubMed

    Yin, Huabing; Pattrick, Nicola; Zhang, Xunli; Klauke, Norbert; Cordingley, Hayley C; Haswell, Steven J; Cooper, Jonathan M

    2008-01-01

    In this paper, we compare a quantitative cell-based assay measuring the intracellular Ca2+ response to the agonist uridine 5'-triphosphate in Chinese hamster ovary cells, in both microfluidic and microtiter formats. The study demonstrates that, under appropriate hydrodynamic conditions, there is an excellent agreement between traditional well-plate assays and those obtained on-chip for both suspended immobilized cells and cultured adherent cells. We also demonstrate that the on-chip assay, using adherent cells, provides the possibility of faster screening protocols with the potential for resolving subcellular information about local Ca2+ flux.

  4. Formation of cadherin-expressing brain nuclei in diencephalic alar plate divisions.

    PubMed

    Yoon, M S; Puelles, L; Redies, C

    2000-11-01

    During the formation of brain nuclei, the vertebrate neural tube is partitioned into distinct embryonic divisions. In this study, the expression of three members of the cadherin family of adhesion molecules (cadherin-6B, cadherin-7, and R-cadherin) was mapped to study the differentiation of gray matter in the division so that diencephalic alar plate of chicken embryos from embryonic day 3 (E3) to E10. At early stages of development (E3-E4), each cadherin is expressed in restricted regions of the diencephalic wall of the neural tube. The borders of some of the expression domains coincide with divisional boundaries. As the mantle layer is formed and increases in thickness from E4 to E8, morphologically discernible aggregates of cells appear that express the three cadherins differentially. These aggregates represent the anlagen of specific diencephalic brain nuclei, e.g., the lateroanterior nucleus, the ventral geniculate nucleus, the nucleus rotundus, the perirotundic area, the principal precommissural nucleus, and the lateral spiriform nucleus. Most of the cadherin-expressing diencephalic nuclei studied in this work apparently derive from a single embryonic division and remain there. The divisional boundaries are replaced gradually by the borders of cadherin-expressing brain nuclei. The current results support the idea that cadherins confer differential adhesiveness to developing structures of gray matter in the diencephalic alar plate. Moreover, they suggest that each cadherin plays a role in the formation of specific brain nuclei within the diencephalic divisions.

  5. Formation of cadherin-expressing brain nuclei in diencephalic alar plate divisions.

    PubMed

    Yoon, M S; Puelles, L; Redies, C

    2000-06-12

    During the formation of brain nuclei, the vertebrate neural tube is partitioned into distinct embryonic divisions. In this study, the expression of three members of the cadherin family of adhesion molecules (cadherin-6B, cadherin-7, and R-cadherin) was mapped to study the differentiation of gray matter in the divisions of the diencephalic alar plate of chicken embryos from embryonic day 3 (E3) to E10. At early stages of development (E3-E4), each cadherin is expressed in restricted regions of the diencephalic wall of the neural tube. The borders of some of the expression domains coincide with divisional boundaries. As the mantle layer is formed and increases in thickness from E4 to E8, morphologically discernible aggregates of cells appear that express the three cadherins differentially. These aggregates represent the anlagen of specific diencephalic brain nuclei, e.g., the lateroanterior nucleus, the ventral geniculate nucleus, the nucleus rotundus, the perirotundic area, the principal precommissural nucleus, and the lateral spiriform nucleus. Most of the cadherin-expressing diencephalic nuclei studied in this work apparently derive from a single embryonic division and remain there. The divisional boundaries are replaced gradually by the borders of cadherin-expressing brain nuclei. The current results support the idea that cadherins confer differential adhesiveness to developing structures of gray matter in the diencephalic alar plate. Moreover, they suggest that each cadherin plays a role in the formation of specific brain nuclei within the diencephalic divisions.

  6. A transient analysis of frost formation on a parallel plate evaporator

    SciTech Connect

    Martinez-Frias, J.; Aceves, S.M.; Hernandez-Guerrero, A.

    1996-12-31

    This paper presents the development of a transient model for evaluating frost formation on a parallel plate evaporator for heat pump applications. The model treats the frost layer as a porous substance, and applies the equations of conservation of mass, momentum and energy to calculate the growth and densification of the frost layer. Empirical correlations for thermal conductivity and tortuosity as a function of density are incorporated from previous studies. Frost growth is calculated as a function of time, Reynolds number, longitudinal location, plate temperature, and ambient air temperature and humidity. The main assumptions are: ideal gas behavior for air and water vapor, uniform frost density and thermal conductivity across the thickness of the frost layer; and quasi-steady conditions during the whole process. The mathematical model is validated by comparing the predicted values of frost thickness and frost density with results obtained in recent experimental studies. A good agreement was obtained in the comparison. The frost formation model calculates pressure drop and heat transfer resistance that result from the existence of the frost layer, and it can therefore be incorporated into a heat pump model to evaluate performance losses due to frosting as a function of weather conditions and time of operation since the last evaporator defrost.

  7. Formation of Island Arc-Trench System due to Plate Subduction on the Basis of Elastic Dislocation Theory

    NASA Astrophysics Data System (ADS)

    Fukahata, Y.; Matsu'ura, M.

    2015-12-01

    The most conspicuous cumulative deformation in subduction zones is the formation of island arc-trench system. A pair of anomalies in topography and free-air gravity, high in the arc and low around the trench, is observed without exceptions all over the world. Since the 1960s, elastic dislocation theory has been widely used to interpret coseismic crustal deformation. For the modeling of longer-term crustal deformation, it is necessary to consider viscoelastic properties of the asthenosphere. By simply applying elastic-viscoelastic dislocation theory to plate subduction, Matsu'ura and Sato (1989, GJI) have shown that some crustal deformation remains after the completion of one earthquake cycle, which means that crustal deformation accumulates with time in a long term due to plate subduction. In fact, by constructing a plate interface model in and around Japan, Hashimoto, Fukui and Matsu'ura (2004, PAGEOPH) have demonstrated that the computed vertical displacements due to steady plate subduction well explain the observed free-air gravity anomaly pattern. Recently, we got a lucid explanation of crustal deformation due to plate subduction. In subduction zones, oceanic plates bend and descend into the mantle. Because the bending of oceanic plates is usually not spontaneous, there exists kinematic interaction between the oceanic and overriding plates, which causes cumulative deformation of the overriding plate. This may be understood based on the law of action and reaction: one is bending of an oceanic plate and the other is deformation of the overriding plate. As a special case, it is useful to consider plate subduction along a part of true circle. In this case, crustal deformation due to steady subduction is solely caused by the effect of gravity, because dislocation along a circle does not cause any intrinsic internal deformation. When an oceanic plate is descending along an arcuate plate interface from the right-hand side, according to dislocation theory, the oceanic

  8. Miniaturization of mitotic index cell-based assay using "wall-less" plate technology.

    PubMed

    Le Guezennec, Xavier; Phong, Mark; Nor, Liyana; Kim, Namyong

    2014-03-01

    The use of microscopic imaging for the accurate assessment of cells in mitosis is hampered by the round morphology of mitotic cells, which renders them poorly adherent and highly susceptible to loss during the washing stage of cell-based assays. Here, to circumvent these limitations, we make use of DropArray, a recent technology that allows high retention of weakly adherent cells and suspension cells. DropArray offers the competitive advantage of maintaining the classic high throughput format of microtiter plates while reducing classic microwell volume by up to 90% by using a drop format. Here, we present a mitotic index cell-based assay using the mitosis marker phospho histone H3 at serine 10 on a DropArray 384-well plate format. Dose-response curve analysis of the mitotic index assay with an antimitotic drug (docetaxel) on DropArray is presented that shows an effective dosage compared to previous established results similar to those obtained with conventional microtiter plates. The mitotic index assay with DropArray showed a Z-factor >0.6. Our results validate DropArray as a suitable platform for high throughput screening for compounds affecting mitosis or the cell cycle. PMID:24611478

  9. Influences of surface hydrophilicity on frost formation on a vertical cold plate under natural convection conditions

    SciTech Connect

    Liu, Zhongliang; Zhang, Xinghua; Wang, Hongyan; Meng, Sheng; Cheng, Shuiyuan

    2007-07-15

    Surface hydrophilicity has a strong influence on frost nucleation according to phase transition theory. To study this effect, a close observation of frost formation and deposition processes on a vertical plate was made under free convection conditions. The formation and shape variation of frost crystals during the initial period are described and the frost thickness variation with time on both hydrophobic and plain copper cold surfaces are presented. The various influencing factors are discussed in depth. The mechanism of surface hydrophilicity influence on frost formation was analyzed theoretically. This revealed that increasing the contact angle can increase the potential barrier and restrain crystal nucleation and growth and thus frost deposition. The experimental results show that the initial water drops formed on a hydrophobic surface are smaller and remain in the liquid state for a longer time compared with ones formed on a plain copper surface. It is also observed that the frost layer deposited on a hydrophobic surface is loose and weak. Though the hydrophobic surface can retard frost formation to a certain extent and causes a looser frost layer, our experimental results show that it does not depress the growth of the frost layer. (author)

  10. Effect of formation temperature on properties of graphite/stannum composite for bipolar plate

    NASA Astrophysics Data System (ADS)

    Selamat, Mohd Zulkefli; Yusuf, Muhammad Yusri Md; Wer, Tio Kok; Sahadan, Siti Norbaya; Malingam, Sivakumar Dhar; Mohamad, Noraiham

    2016-03-01

    Bipolar plates are key components in Proton Exchange Membrane (PEM) fuel cells. They carry current away from the cell and withstand the clamping force of the stack assembly. Therefore, PEM fuel cell bipolar plates must have high electrical conductivity and adequate mechanical strength, in addition to being light weight and low cost in terms of both applicable materials and production methods. In this research, the raw materials used to fabricate the high performance bipolar plate are Graphite (Gr), Stannum (Sn) and Polypropylene (PP). All materials used was in powder form and Gr and Sn act as fillers and the PP acts as binder. The ratio of fillers (Gr/Sn) and binder (PP) was fixed at 80:20. For the multi-conductive filler, small amount of Sn, which is 10 up to 20wt% (from the total weight of fillers 80%) have been added into Gr/Sn/PP composite. The fillers were mixed by using the ball mill machine. The second stage of mixing process between the mixer of fillers and binder is also carried out by using ball mill machine before the compaction process by the hot press machine. The effect of formation temperatures (160°C-170°C) on the properties of Gr/Sn/PP composite had been studied in detail, especially the electrical conductivity, bulk density, hardness and microstructure analysis of Gr/Sn/PP composite. The result shows that there are significant improvement in the electrical conductivity and bulk density, which are exceeding the US-DoE target with the maximum value of 265.35 S/cm and 1.682g/cm3 respectively.

  11. Enhancement of measurement sensitivity in the formation of shear interferograms of transparent plates with small residual wedging

    SciTech Connect

    But', A I; Lyalikov, A M

    2011-10-31

    We have proposed a method for increasing the sensitivity of measurements of the wedge angle in transparent plates. The method is based on formation of the holographic shear interferograms using a combination of 180 Degree-Sign rotation of the plate with byturn adjustment of interferograms in its images to an infinitely wide fringe. The sensitivity enhancement is due to the increased number of interference fringes in the observed images of the wedged plate, which favours the reduction of the measurement error during optical processing of the obtained interferograms. Data on the experimental validation of the proposed method are presented.

  12. Large-format imaging plate and weissenberg camera for accurate protein crystallographic data collection using synchrotron radiation.

    PubMed

    Sakabe, K; Sasaki, K; Watanabe, N; Suzuki, M; Wang, Z G; Miyahara, J; Sakabe, N

    1997-05-01

    Off-line and on-line protein data-collection systems using an imaging plate as a detector are described and their components reported. The off-line scanner IPR4080 was developed for a large-format imaging plate ;BASIII' of dimensions 400 x 400 mm and 400 x 800 mm. The characteristics of this scanner are a dynamic range of 10(5) photons pixel(-1), low background noise and high sensitivity. A means of reducing electronic noise and a method for finding the origin of the noise are discussed in detail. A dedicated screenless Weissenberg camera matching IPR4080 with synchrotron radiation was developed and installed on beamline BL6B at the Photon Factory. This camera can attach one or two sheets of 400 x 800 mm large-format imaging plate inside the film cassette by evacuation. The positional reproducibility of the imaging plate on the cassette is so good that the data can be processed by batch job. Data of 93% completeness up to 1.6 A resolution were collected on a single axis rotation and the value of R(merge) becomes 4% from a tetragonal lysozyme crystal using a set of two imaging-plate sheets. Comparing two types of imaging plates, the signal-to-noise ratio of the ST-VIP-type imaging plate is 25% better than that of the BASIII-type imaging plate for protein data collection using 1.0 and 0.7 A X-rays. A new on-line protein data-collection system with imaging plates is specially designed to use synchrotron radiation X-rays at maximum efficiency.

  13. Rapid and efficient generation of neurons from human pluripotent stem cells in a multititre plate format.

    PubMed

    Zhang, Miao; Schöler, Hans R; Greber, Boris

    2013-01-01

    Existing protocols for the generation of neurons from human pluripotent stem cells (hPSCs) are often tedious in that they are multistep procedures involving the isolation and expansion of neural precursor cells, prior to terminal differentiation. In comparison to these time-consuming approaches, we have recently found that combined inhibition of three signaling pathways, TGFβ/SMAD2, BMP/SMAD1, and FGF/ERK, promotes rapid induction of neuroectoderm from hPSCs, followed by immediate differentiation into functional neurons. Here, we have adapted our procedure to a novel multititre plate format, to further enhance its reproducibility and to make it compatible with mid-throughput applications. It comprises four days of neuroectoderm formation in floating spheres (embryoid bodies), followed by a further four days of differentiation into neurons under adherent conditions. Most cells obtained with this protocol appear to be bipolar sensory neurons. Moreover, the procedure is highly efficient, does not require particular expert skills, and is based on a simple chemically defined medium with cost-efficient small molecules. Due to these features, the procedure may serve as a useful platform for further functional investigation as well as for cell-based screening approaches requiring human sensory neurons or neurons of any type. PMID:23486189

  14. Growth plate regulation and osteochondroma formation: insights from tracing proteoglycans in zebrafish models and human cartilage.

    PubMed

    de Andrea, Carlos E; Prins, Frans A; Wiweger, Malgorzata I; Hogendoorn, Pancras C W

    2011-06-01

    Proteoglycans are secreted into the extracellular matrix of virtually all cell types and function in several cellular processes. They consist of a core protein onto which glycosaminoglycans (e.g., heparan or chondroitin sulphates), are attached. Proteoglycans are important modulators of gradient formation and signal transduction. Impaired biosynthesis of heparan sulphate glycosaminoglycans causes osteochondroma, the most common bone tumour to occur during adolescence. Cytochemical staining with positively charged dyes (e.g., polyethyleneimine-PEI) allows, visualisation of proteoglycans and provides a detailed description of how proteoglycans are distributed throughout the cartilage matrix. PEI staining was studied by electron and reflection contrast microscopy in human growth plates, osteochondromas and five different proteoglycan-deficient zebrafish mutants displaying one of the following skeletal phenotypes: dackel (dak/ext2), lacking heparan sulphate and identified as a model for human multiple osteochondromas; hi307 (β3gat3), deficient for most glycosaminoglycans; pinscher (pic/slc35b2), presenting with defective sulphation of glycosaminoglycans; hi954 (uxs1), lacking most glycosaminoglycans; and knypek (kny/gpc4), missing the protein core of the glypican-4 proteoglycan. The panel of genetically well-characterized proteoglycan-deficient zebrafish mutants serves as a convincing and comprehensive study model to investigate proteoglycan distribution and the relation of this distribution to the model mutation status. They also provide insight into the distributions and gradients that can be expected in the human homologue. Human growth plate, wild-type zebrafish and fish mutants with mild proteoglycan defects (hi307 and kny) displayed proteoglycans distributed in a gradient throughout the matrix. Although the mutants pic and hi954, which had severely impaired proteoglycan biosynthesis, showed no PEI staining, dak mutants demonstrated reduced PEI staining and no

  15. Plate-tectonic boundary formation by grain-damage and pinning

    NASA Astrophysics Data System (ADS)

    Bercovici, David

    2015-04-01

    Shear weakening in the lithosphere is an essential ingredient for understanding how and why plate tectonics is generated from mantle convection on terrestrial planets. I present continued work on a theoretical model for lithospheric shear-localization and plate generation through damage, grain evolution and Zener pinning in two-phase (polycrystalline) lithospheric rocks. Grain size evolves through the competition between coarsening, which drives grain-growth, with damage, which drives grain reduction. The interface between phases controls Zener pinning, which impedes grain growth. Damage to the interface enhances the Zener pinning effect, which then reduces grain-size, forcing the rheology into the grain-size-dependent diffusion creep regime. This process thus allows damage and rheological weakening to co-exist, providing a necessary shear-localizing feedback. Moreover, because pinning inhibits grain-growth it promotes shear-zone longevity and plate-boundary inheritance. This theory has been applied recently to the emergence of plate tectonics in the Archean by transient subduction and accumulation of plate boundaries over 1Gyr, as well as to rapid slab detachment and abrupt tectonic changes. New work explores the saturation of interface damage at low interface curvature (e.g., because it is associated with larger grains that take up more of the damage, and/or because interface area is reduced). This effect allows three possible equilibrium grain-sizes for a given stress; a small-grain-size high-shear state in diffusion creep, a large grain-size low shear state in dislocation creep, and an intermediate state (often near the deformation map phase-boundary). The low and high grain-size states are stable, while the intermediate one is unstable. This implies that a material deformed at a given stress can acquire two stable deformation regimes, a low- and high- shear state; these are indicative of plate-like flows, i.e, the coexistence of both slowly deforming plates

  16. Titer-plate formatted continuous flow thermal reactors: Design and performance of a nanoliter reactor.

    PubMed

    Chen, Pin-Chuan; Park, Daniel S; You, Byoung-Hee; Kim, Namwon; Park, Taehyun; Soper, Steven A; Nikitopoulos, Dimitris E; Murphy, Michael C

    2010-08-01

    Arrays of continuous flow thermal reactors were designed, configured, and fabricated in a 96-device (12 × 8) titer-plate format with overall dimensions of 120 mm × 96 mm, with each reactor confined to a 8 mm × 8 mm footprint. To demonstrate the potential, individual 20-cycle (740 nL) and 25-cycle (990 nL) reactors were used to perform the continuous flow polymerase chain reaction (CFPCR) for amplification of DNA fragments of different lengths. Since thermal isolation of the required temperature zones was essential for optimal biochemical reactions, three finite element models, executed with ANSYS (v. 11.0, Canonsburg, PA), were used to characterize the thermal performance and guide system design: (1) a single device to determine the dimensions of the thermal management structures; (2) a single CFPCR device within an 8 mm × 8 mm area to evaluate the integrity of the thermostatic zones; and (3) a single, straight microchannel representing a single loop of the spiral CFPCR device, accounting for all of the heat transfer modes, to determine whether the PCR cocktail was exposed to the proper temperature cycling. In prior work on larger footprint devices, simple grooves between temperature zones provided sufficient thermal resistance between zones. For the small footprint reactor array, 0.4 mm wide and 1.2 mm high fins were necessary within the groove to cool the PCR cocktail efficiently, with a temperature gradient of 15.8°C/mm, as it flowed from the denaturation zone to the renaturation zone. With temperature tolerance bands of ±2°C defined about the nominal temperatures, more than 72.5% of the microchannel length was located within the desired temperature bands. The residence time of the PCR cocktail in each temperature zone decreased and the transition times between zones increased at higher PCR cocktail flow velocities, leading to less time for the amplification reactions. Experiments demonstrated the performance of the CFPCR devices as a function of flow

  17. Titer-plate formatted continuous flow thermal reactors: Design and performance of a nanoliter reactor

    PubMed Central

    Chen, Pin-Chuan; Park, Daniel S.; You, Byoung-Hee; Kim, Namwon; Park, Taehyun; Soper, Steven A.; Nikitopoulos, Dimitris E.; Murphy, Michael C.

    2010-01-01

    Arrays of continuous flow thermal reactors were designed, configured, and fabricated in a 96-device (12 × 8) titer-plate format with overall dimensions of 120 mm × 96 mm, with each reactor confined to a 8 mm × 8 mm footprint. To demonstrate the potential, individual 20-cycle (740 nL) and 25-cycle (990 nL) reactors were used to perform the continuous flow polymerase chain reaction (CFPCR) for amplification of DNA fragments of different lengths. Since thermal isolation of the required temperature zones was essential for optimal biochemical reactions, three finite element models, executed with ANSYS (v. 11.0, Canonsburg, PA), were used to characterize the thermal performance and guide system design: (1) a single device to determine the dimensions of the thermal management structures; (2) a single CFPCR device within an 8 mm × 8 mm area to evaluate the integrity of the thermostatic zones; and (3) a single, straight microchannel representing a single loop of the spiral CFPCR device, accounting for all of the heat transfer modes, to determine whether the PCR cocktail was exposed to the proper temperature cycling. In prior work on larger footprint devices, simple grooves between temperature zones provided sufficient thermal resistance between zones. For the small footprint reactor array, 0.4 mm wide and 1.2 mm high fins were necessary within the groove to cool the PCR cocktail efficiently, with a temperature gradient of 15.8°C/mm, as it flowed from the denaturation zone to the renaturation zone. With temperature tolerance bands of ±2°C defined about the nominal temperatures, more than 72.5% of the microchannel length was located within the desired temperature bands. The residence time of the PCR cocktail in each temperature zone decreased and the transition times between zones increased at higher PCR cocktail flow velocities, leading to less time for the amplification reactions. Experiments demonstrated the performance of the CFPCR devices as a function of flow

  18. One-step synthesis of collagen hybrid gold nanoparticles and formation on Egyptian-like gold-plated archaeological ivory.

    PubMed

    Spadavecchia, Jolanda; Apchain, Emilande; Albéric, Marie; Fontan, Elisabeth; Reiche, Ina

    2014-08-01

    A one-step method is reported to synthesize hybrid gold nanoparticles (AuNPs) by reduction of HAuCl4 in acetic solution in the presence of collagen (Col), dicarboxylic acid-terminated polyethylene glycol (PEG), and cetyltetrammonium bromide (CTAB) mixed with hydoxyapatite (HAP) as surfactants. Such formation process of AuNPs was shown to be responsible for purple stains naturally formed on Egyptianizing archaeological gilded ivories from 8th BC Syria. The understanding of this formation mechanism, which most likely involves a step with hybrid AuNPs, allows the establishing of an authenticity marker of ancient gold-plated ivories.

  19. Development prospects for Bazhenov formation bituminous claystones in the southeast of the West Siberian Plate (Tomsk Region)

    NASA Astrophysics Data System (ADS)

    Belozerov, V. B.; Baranov, V. E.; Dmitriev, A. Y.

    2015-02-01

    The article considers the use of time-tested bituminous shale development technologies in the southeast of the West Siberian Plate (Tomsk Region). A research target is the bituminous claystones of the Bazhenov formation. The Bazhenov formation was divided into stratigraphic units, and the sequence of forming these units within the territory under study was restored on the basis of the peculiarities of the Bazhenov formation section structure with gamma-ray logging data. The joint analysis of logs (gamma-ray logging, resistivity logging, SP logging, neutron gamma-ray logging, induction logging) and core data revealed the wide development of carbonatization processes in the lower stratigraphic units of the Bazhenov formation, whereas the upper, most bituminous units do not have the signs of carbonatization. It is a favorable factor for using the existing technologies of producing hydrocarbons from analogous sedimentary deposits. Considering the degree of lithological disconnection of an oilbearing object from adjacent reservoir formations allows making a conclusion that the application of the existing technologies for developing bituminous claystones can be implemented only in the insignificant territory of the area under study where the Bazhenov formation overlies Georgiev formation claystones being over 8 meters thick. To develop the oil and gas potential of the Bazhenov formation in other territories, there will be a need for new technologies that allow forming a fracture-cavernous matrix in a carbonate rock.

  20. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation.

    PubMed

    Xu, Haitao; Xue, Zichao; Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation.

  1. Callus Formation and Mineralization after Fracture with Different Fixation Techniques: Minimally Invasive Plate Osteosynthesis versus Open Reduction Internal Fixation

    PubMed Central

    Ding, Haoliang; Qin, Hui; An, Zhiquan

    2015-01-01

    Minimally invasive plate osteosynthesis(MIPO) has been considered as an alternative for fracture treatment. Previous study has demonstrated that MIPO technique has the advantage of less soft tissue injury compared with open reduction internal fixation (ORIF). However, the comparison of callus formation and mineralization between two plate osteosynthesis methods remains unknown. In this experiment, ulna fracture model was established in 42 beagle dogs. The fractures underwent reduction and internal fixation with MIPO or ORIF. Sequential fluorescent labeling and radiographs were applied to determine new callus formation and mineralization in two groups after operation. At 4, 8 and 12 weeks postoperatively, the animals were selected to be sacrificed and the ulna specimens were analyzed by Micro-CT. The sections were also treated with Masson staining for histological evaluation. More callus formation was observed in MIPO group in early stage of fracture healing. The fracture union rate has no significant difference between two groups. The results indicate that excessive soft tissue stripping may impact early callus formation. As MIPO technique can effectively reduce soft tissue injury with little incision, it is considered to be a promising alternative for fracture fixation. PMID:26444295

  2. Formation and Evaluation of Electroless-Plated Barrier Films for High-Aspect-Ratio Through-Si Vias

    NASA Astrophysics Data System (ADS)

    Miyake, Hiroshi; Inoue, Fumihiro; Yokoyama, Takumi; Shimizu, Tomohiro; Tanaka, Shukichi; Terui, Toshifumi; Shingubara, Shoso

    2011-05-01

    The formation of a diffusion barrier layer in a through-Si via (TSV) has been studied with a combination of nanoparticle catalyst and electroless plating (ELP). We used Au-nanoparticles (Au-NPs) or Pd-nanoparticles (Pd-NPs) as catalysts for ELP of Ni- and Co-alloy barrier layers. We studied deposition of Ni-B and Co-B films in high-aspect-ratio (AR) TSV. Then, we succeeded in controlling the deposition profile of Ni-B in a high-AR TSV by the addition of bis(3-sulfopropyl)-disulfide (SPS). SPS turned out to be an inhibitor of electroless plating of Ni-B. On the other hand, the Co-B film was deposited conformally without additive. The electrical resistivity of Cu after annealing Cu/barrier stacked structure suggests that Co-B has better thermal stability than Ni-B.

  3. Optimization of reaction parameters in hydrothermal synthesis: a strategy towards the formation of CuS hexagonal plates

    PubMed Central

    2013-01-01

    Background For decades, copper sulphide has been renowned as the superior optical and semiconductor materials. Its potential applications can be ranged from solar cells, lithium-ion batteries, sensors, and catalyst systems. The synthesis methodologies of copper sulphide with different controlled morphology have been widely explored in the literature. Nevertheless, the understanding on the formation chemistry of CuS is still limited. The ultimate approach undertaking in this article is to investigate the formation of CuS hexagonal plates via the optimization of reaction parameters in hydrothermal reaction between copper (II) nitrate and sodium thiosulphate without appending any assistant agent. Results Covellite (CuS) hexagonal plates were formed at copper ion: thiosulphate ion (Cu2+:S2O32−) mole ratio of 1:2 under hydrothermal treatment of 155°C for 12 hours. For synthesis conducted at reaction temperature lower than 155°C, copper sulphate (CuSO4), krohnite (NaCu2(SO4)(H2O)2] and cyclooctasulphur (S8) were present as main impurities with covellite (CuS). When Cu2+:S2O32− mole ratio was varied to 1: 1 and 1: 1.5, phase pure plate-like natrochalcite [NaCu2(SO4)(H2O)] and digenite (Cu9S5) were produced respectively. Meanwhile, mixed phases of covellite (CuS) and cyclooctasulphur (S8) were both identified when Cu2+:S2O32− mole ratio was varied to 1: 2.5, 1: 3 and 1: 5 as well as when reaction time was shortened to 1 hour. Conclusions CuS hexagonal plates with a mean edge length of 1 μm, thickness of 100 nm and average crystallite size of approximately (45 ± 2) nm (Scherrer estimation) were successfully synthesized via assisting agent- free hydrothermal method. Under a suitable Cu2+:S2O32− mole ratio, we evidenced that the formation of covellite (CuS) is feasible regardless of the reaction temperature applied. However, a series of impurities were attested with CuS if reaction temperature was not elevated high enough for the additional crystallite

  4. Cretaceous evolution of the Indian Plate and consequences for the formation, deformation and obduction of adjacent oceanic crust

    NASA Astrophysics Data System (ADS)

    Gaina, C.; Van Hinsbergen, D. J.; Spakman, W.

    2012-12-01

    As part of the gradual Gondwana dispersion that started in the Jurassic, the Indian tectonic block was rifted away from the Antarctica-Australian margins, probably in the Early-Mid Cretaceous and started its long journey to the north until it collided with Eurasia in the Tertiary. In this contribution first we will revise geophysical and geological evidences for the formation of oceanic crust between India and Antarctica, India and Madagascar, and India and Somali/Arabian margins. This information and possible oceanic basin age interpretation are placed into regional kinematic models. Three important compressional events NW and W of the Indian plate are the result of the opening of the Enderby Basin from 132 to 124 Ma, the first phase of seafloor spreading in the Mascarene basin approximately from 84 to 80 Ma, and the incipient opening of the Arabian Sea and the Seychelles microplate formation around 65 to 60 Ma. Based on retrodeformation of the Afghan-Pakistan part of the India-Asia collision zone and the eastern Oman margin, the ages of regional ophiolite emplacement and crystallization of its oceanic crust, as well as the plate tectonic setting of these ophiolites inferred from its geochemistry, we evaluate possible scenarios for the formation of intra-oceanic subduction zones and their evolution until ophiolite emplacement time. Our kinematic scenarios are constructed for several regional models and are discussed in the light of global tomographic models that may image some of the subducted Cretaceous oceanic lithosphere.

  5. Self-similar formation of an inverse cascade in vibrating elastic plates

    NASA Astrophysics Data System (ADS)

    Düring, Gustavo; Josserand, Christophe; Rica, Sergio

    2015-05-01

    The dynamics of random weakly nonlinear waves is studied in the framework of vibrating thin elastic plates. Although it has been previously predicted that no stationary inverse cascade of constant wave action flux could exist in the framework of wave turbulence for elastic plates, we present substantial evidence of the existence of a time-dependent inverse cascade, opening up the possibility of self-organization for a larger class of systems. This inverse cascade transports the spectral density of the amplitude of the waves from short up to large scales, increasing the distribution of long waves despite the short-wave fluctuations. This dynamics appears to be self-similar and possesses a power-law behavior in the short-wavelength limit which significantly differs from the exponent obtained via a Kolmogorov dimensional analysis argument. Finally, we show explicitly a tendency to build a long-wave coherent structure in finite time.

  6. Touch-plate and statolith formation in graviceptors of ephyrae which developed while weightless in space

    NASA Technical Reports Server (NTRS)

    Spangenberg, D. B.; Coccaro, E.; Schwarte, R.; Lowe, B.

    1996-01-01

    Ultrastructural studies of the statocysts and touch-plates of graviceptors (rhopalia) of Aurelia ephyrae revealed that (1) touch-plate hair cells are present; and (2) cytoplasmic strands from the hair cell bases extend from the neurite plexus to touch similar strands from the lithocytes. This close association of hair cell neurites and statocysts may have important implications regarding the transmitting and processing of positional information with respect to the gravity vector. Graviceptors of ephyrae which developed while weightless in microgravity were compared with controls at the ultrastructural level. We found that hair cells of ephyrae which developed in microgravity had fewer lipid droplets in the large spaces near their bases as compared with 1 g controls. In the ephyrae from the first microgravity experiment, hair cells had more large apical vacuoles with filamentous content than were found in hair cells of ephyrae from the second experiment and controls. The neurite plexus and the network of cytoplasmic strands extending to the statocysts were not different in microgravity-developed ephyrae from controls. Behavioral differences in swimming and orienting in ephyrae in microgravity and controls (reported earlier) were not explained by morphological differences in the hair cells of the touch-plates or the statocysts, although functional differences apparently occurred.

  7. Precambrian Plate Tectonics and the Formation of the Canadian Shield: Seismic Evidence from Hudson Bay

    NASA Astrophysics Data System (ADS)

    Bastow, I. D.; Thompson, D. A.; Kendall, J. M.; Helffrich, G. R.; Wookey, J.; Snyder, D. B.; Eaton, D. W.; Darbyshire, F. A.

    2010-12-01

    The Canadian Shield is one of the largest exposures of Precambrian rocks on Earth. It is a mosaic of several Archean terranes that were brought together during a series of Paleoproterozoic orogens culminating in the so-called Trans-Hudson Orogen (THO), which is thought to have been similar to the Himalayan orogen in scale and nature. The tectonic evolution and lithospheric subdivisions of this region are poorly understood, but new seismic networks in northern Hudson Bay provide fresh information sources to place constraints on the Precambrian processes that formed and shaped it. Using data from a network of 12 broadband seismic stations in the northern part of Hudson Bay that complement existing POLARIS and CNSN networks in the region, we report on a combined study of seismic anisotropy, travel-time tomography, and receiver functions. While tomographic images reveal no clear seismological distinction between Archean and Proterozoic mantle, results from the study of seismic anisotropy show that much of the northern Hudson Bay region retains a strong signature of Archean-to-Paleoproterozoic tectonics - in particular the THO. The receiver function study also provides evidence in support of this 1.8 Ga orogenic event, but the simplicity of crustal structure in the oldest terranes as well as the scale of orogenic belts provides little evidence in support modern-day-style plate tectonics. When reviewed in light of age and compositional constraints from the geological record, our seismic observations point towards a secular change from non-plate tectonic deformation during the Paleo- to Mesoarchean evolving towards fully-developed modern-style plate tectonic interactions during the Paleoproterozoic.

  8. Plate interface rheological switches during subduction infancy: Control on slab penetration and metamorphic sole formation

    NASA Astrophysics Data System (ADS)

    Agard, P.; Yamato, P.; Soret, M.; Prigent, C.; Guillot, S.; Plunder, A.; Dubacq, B.; Chauvet, A.; Monié, P.

    2016-10-01

    Subduction infancy corresponds to the first few million years following subduction initiation, when slabs start their descent into the mantle. It coincides with the transient (yet systematic) transfer of material from the top of the slab to the upper plate, as witnessed by metamorphic soles welded beneath obducted ophiolites. Combining structure-lithology-pressure-temperature-time data from metamorphic soles with flow laws derived from experimental rock mechanics, this study highlights two main successive rheological switches across the subduction interface (mantle wedge vs. basalts, then mantle wedge vs. sediments; at ∼800 °C and ∼600 °C, respectively), during which interplate mechanical coupling is maximized by the existence of transiently similar rheologies across the plate contact. We propose that these rheological switches hinder slab penetration and are responsible for slicing the top of the slab and welding crustal pieces (high- then low-temperature metamorphic soles) to the base of the mantle wedge during subduction infancy. This mechanism has implications for the rheological properties of the crust and mantle (and for transient episodes of accretion/exhumation of HP-LT rocks in mature subduction systems) and highlights the role of fluids in enabling subduction to overcome the early resistance to slab penetration.

  9. Periodic acid-Schiff's reagent assay for carbohydrates in a microtiter plate format.

    PubMed

    Kilcoyne, Michelle; Gerlach, Jared Q; Farrell, Mark P; Bhavanandan, Veer P; Joshi, Lokesh

    2011-09-01

    Microtiter plate colorimetric assays are widely used for analysis of carbohydrates and glycoconjugates. However, mucins are often not easily detected, as they have low neutral sugar content. We have adapted and optimised the periodic acid-Schiff's reagent (PAS) staining for microtiter plate assay by examining five factors: concentration and volume of periodic acid, oxidation time, volume of Schiff's reagent, and color development time. This assay requires just 25 μl of sample, utilises standardised Schiff's reagent, and has decreased assay time (140 min to completion). Seventeen monosaccharides (acidic, neutral, basic, phosphorylated, and deoxy) and four disaccharides were assessed. PAS-positive carbohydrates (amino, N-acetylamino, deoxy, and certain neutral monosaccharides, and sialic acids) responded linearly within a 10-100 nmol range approximately, which varied for each carbohydrate. The assay response for fetuin and porcine gastric mucin (PGM) was linear up to 150 μg (highest concentration tested), with no response from nonglycosylated protein. A lower response for asialofetuin was observed, but desialylated PGM preparations were similar or higher in response than their sialylated counterparts. The simplicity and low sample consumption of this method make it an excellent choice for screening or quantitation of chromatographic fractions containing carbohydrates and glycoconjugates, especially in the case of mucins.

  10. Antibody array in a multiwell plate format for the sensitive and multiplexed detection of important plant pathogens.

    PubMed

    Charlermroj, Ratthaphol; Himananto, Orawan; Seepiban, Channarong; Kumpoosiri, Mallika; Warin, Nuchnard; Gajanandana, Oraprapai; Elliott, Christopher T; Karoonuthaisiri, Nitsara

    2014-07-15

    The global seed market is considered to be an important industry with a total value of $10,543 million US dollars in 2012. Because plant pathogens such as bacteria and viruses cause a significant economic loss to both producers and exporters, the seed export industry urgently requires rapid, sensitive, and inexpensive testing for the pathogens to prevent disease spreading worldwide. This study developed an antibody array in a multiwell plate format to simultaneously detect four crucial plant pathogens, namely, a bacterial fruit blotch bacterium Acidovorax avenae subsp. citrulli (Aac), Chilli veinal mottle virus (ChiVMV, potyvirus), Watermelon silver mottle virus (WSMoV, tospovirus serogroup IV), and Melon yellow spot virus (MYSV, tospovirus). The capture antibodies specific to the pathogens were immobilized on each well at preassigned positions by an automatic microarrayer. The antibodies on the arrays specifically captured the corresponding pathogens present in the sample extracts. The presence of pathogens bound on the capture antibodies was subsequently detected by a cocktail of fluorescently conjugated secondary antibodies. The limits of detection of the developed antibody array for the detection of Aac, ChiVMV, WSMoV, and MYSV were 5 × 10(5) CFU/mL, 30 ng/mL, 1000 ng/mL, and 160 ng/mL, respectively, which were very similar to those of the conventional ELISA method. The antibody array in a multiwell plate format accurately detected plant pathogens in single and multiple detections. Moreover, this format enables easy handling of the assay at a higher speed of operation. PMID:24945525

  11. Abrupt Change in North American Plate Motion: Magnetostratigraphy and Paleopoles of the Early Jurassic Moenave Formation

    NASA Astrophysics Data System (ADS)

    Hutny, M. K.; Steiner, M. B.

    2001-12-01

    The J-1 cusp marks a dramatic ~ 180° change in the apparent motion of the magnetic pole with respect to North America. The cusp is defined by a sequence of poles: Chinle - Moenave - Kayenta. The Moenave pole (Ekstrand and Butler, 1989), which forms the point of the cusp, was obtained primarily from the lower member (Dinosaur Canyon) of the three-member Moenave Formation. We present new paleomagnetic data from the upper two members (Whitmore Point and Springdale Sandstone) of the formation. The Vermillion Cliffs in southern Utah present excellent exposures of the Moenave Formation. At this location, the Moenave rests uncomformably on the Late Triassic Chinle Group, although to the southeast it overlies it in a conformable manner. The Moenave is seemingly conformably overlain by the Kayenta Formation. Our study identified six polarity intervals in 100 meters of section. A preliminary paleopole from the Whitmore Point Member falls within the 95% confidence limits of the Dinosaur Canyon pole (Ekstrand and Butler, 1989), as does our pole from the top Springdale Sandstone member. If the apparent polar wander does indeed represent motion of the North American continent, then the reversal in direction implied by the J-1 cusp takes place after the deposition of the Springdale Sandstone, and either before or during the deposition of the lower Kayenta Formation. No directions intermediate between the Moenave and Kayenta directions were observed up through the uppermost Moenave strata. Within the Moenave, the lack of discernable change in magnetic direction between the three members suggests continuous deposition. This result is consistent with the observed mutually interfingering nature of the Whitmore Point and Springdale Sandstone. The sudden change in magnetic direction between the top of the Moenave and the Kayenta suggests the possibility of an unconformity between the two formations, and/or rapid continental motion following the turnaround.

  12. A Novel 96well-formatted Micro-gap Plate Enabling Drug Response Profiling on Primary Tumour Samples

    NASA Astrophysics Data System (ADS)

    Ma, Wei-Yuan; Hsiung, Lo-Chang; Wang, Chen-Ho; Chiang, Chi-Ling; Lin, Ching-Hung; Huang, Chiun-Sheng; Wo, Andrew M.

    2015-04-01

    Drug-based treatments are the most widely used interventions for cancer management. Personalized drug response profiling remains inherently challenging with low cell count harvested from tumour sample. We present a 96well-formatted microfluidic plate with built-in micro-gap that preserves up to 99.2% of cells during multiple assay/wash operation and only 9,000 cells needed for a single reagent test (i.e. 1,000 cells per test spot x 3 selected concentration x triplication), enabling drug screening and compatibility with conventional automated workstations. Results with MCF7 and MDA-MB-231 cell lines showed that no statistical significance was found in dose-response between the device and conventional 96-well plate control. Primary tumour samples from breast cancer patients tested in the device also showed good IC50 prediction. With drug screening of primary cancer cells must consider a wide range of scenarios, e.g. suspended/attached cell types and rare/abundant cell availability, the device enables high throughput screening even for suspended cells with low cell count since the signature microfluidic cell-trapping feature ensures cell preservation in a multiple solution exchange protocol.

  13. A Cell-based PDE4 Assay in 1536-well Plate format for High Throughput Screening

    PubMed Central

    Titus, Steven A.; Li, Xiao; Southall, Noel; Lu, Jianming; Inglese, James; Brasch, Michael; Austin, Christopher P.; Zheng, Wei

    2009-01-01

    The cyclic nucleotide phosphodiesterases (PDEs) are intracellular enzymes that catalyze the hydrolysis of 3', 5'-cyclic nucleotides, such as cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP), to their corresponding 5'-nucleotide monophosphates. These enzymes play an important role in controlling cellular concentrations of cyclic nucleotides and thus regulate a variety of cellular signaling events. PDEs are emerging as drug targets for several diseases including asthma, cardiovascular disease, ADHD, Parkinson’s disease, and Alzheimer’s disease. Though biochemical assays with purified recombinant PDE enzymes and cAMP or cGMP substrate are commonly used for compound screening, cell-based assays would provide a better assessment of compound activity in a more physiological context. Here we report the development and validation of a new cell-based PDE4 assay using a constitutively active GPCR as a driving force for cAMP production and a cyclic nucleotide gated (CNG) cation channel as a biosensor in 1536-well plates. PMID:18591513

  14. Dynamics of intra-oceanic subduction initiation, part 2: supra-subduction zone ophiolite formation and metamorphic sole exhumation in context of absolute plate motions

    NASA Astrophysics Data System (ADS)

    Maffione, M.; Van Hinsbergen, D. J. J.; Peters, K.; Spakman, W.; Guilmette, C.; Thieulot, C.; Plumper, O.; Guerer, D.; Brouwer, F. M.; Aldanmaz, E.; Kaymakci, N.

    2015-12-01

    Analyzing subduction initiation is key for understanding the coupling between plate tectonics and underlying mantle. Here we focus on supra-subduction zone (SSZ) ophiolites and how their formation links to intra-oceanic subduction initiation in an absolute plate motion frame. SSZ ophiolites form the majority of exposed oceanic lithosphere fragments and are widely recognized to have formed during intra-oceanic subduction initiation. Structural, petrological, geochemical, and plate kinematic constraints on their kinematic evolution show that SSZ crust forms at forearc spreading centers at the expense of a mantle wedge, thereby flattening the nascent slab. This leads to the typical inverted pressure gradients found in metamorphic soles that form at the subduction plate contact below and during SSZ crust crystallization. Former spreading centers are preserved in forearcs when subduction initiates along transform faults or off-ridge oceanic detachments. We show how these are reactivated when subduction initiates in the absolute plate motion direction of the inverting weakness zone. Upon inception of slab-pull due to e.g. eclogitization, the sole is separated from the slab, remains welded to the thinned overriding plate lithosphere and can become intruded by mafic dikes upon asthenospheric influx into the mantle wedge. We propound that most ophiolites thus formed under special geodynamic circumstances and may not be representative of normal oceanic crust. Our study highlights how far-field geodynamic processes and absolute plate motions may force intra-oceanic subduction initiation as key towards advancing our understanding of the entire plate tectonic cycle.

  15. Formation of Australian continental margin highlands driven by plate-mantle interaction

    NASA Astrophysics Data System (ADS)

    Müller, R. Dietmar; Flament, Nicolas; Matthews, Kara J.; Williams, Simon E.; Gurnis, Michael

    2016-05-01

    Passive margin highlands occur on most continents on Earth and play a critical role in the cycle of weathering, erosion, and atmospheric circulation. Yet, in contrast to the well-developed understanding of collisional mountain belts, such as the Alps and Himalayas, the origin of less elevated (1-2 km) passive margin highlands is still unknown. The eastern Australian highlands are a prime example of these plateaus, but compared to others they have a well-documented episodic uplift history spanning 120 million years. We use a series of mantle convection models to show that the time-dependent interaction of plate motion with mantle downwellings and upwellings accounts for the broad pattern of margin uplift phases. Initial dynamic uplift of 400-600 m from 120-80 Ma was driven by the eastward motion of eastern Australia's margin away from the sinking eastern Gondwana slab, followed by tectonic quiescence to about 60 Ma in the south (Snowy Mountains). Renewed uplift of ∼700 m in the Snowy Mountains is propelled by the gradual motion of the margin over the edge of the large Pacific mantle upwelling. In contrast the northernmost portion of the highlands records continuous uplift from 120 Ma to present-day totalling about 800 m. The northern highlands experienced a continuous history of dynamic uplift, first due to the end of subduction to the east of Australia, then due to moving over a large passive mantle upwelling. In contrast, the southern highlands started interacting with the edge of the large Pacific mantle upwelling ∼ 40- 50 million years later, resulting in a two-phase uplift history. Our results are in agreement with published uplift models derived from river profiles and the Cretaceous sediment influx into the Ceduna sub-basin offshore southeast Australia, reflecting the fundamental link between dynamic uplift, fluvial erosion and depositional pulses in basins distal to passive margin highlands.

  16. Thermochemical Constraints For the Formation Conditions of the Hydrothermal Alteration Mineralogy of Home Plate and Columbia Hills

    NASA Astrophysics Data System (ADS)

    Filiberto, J.; Schwenzer, S. P.

    2012-12-01

    Home Plate is a plateau in the Columbia Hills of Gusev Crater. It is dominated by igneous minerals (olivine, pyroxene, and magnetite) with small amounts of alteration minerals (hematite and nanophase oxides). Surrounding Home Plate are deposits containing diverse secondary mineral assemblages: Fe3+-sulfates deposits at Paso Robles, Dead Sea, Shredded, Arad, Tyrone, and Troy; Hematite-rich outcrops between Home Plate and Tyrone; SiO2-rich deposits possibly containing pyrite and/or marcasite at Fuzzy Smith; SiO2-rich, possibly opaline silica, deposits at Northern Valley, Eastern Valley, and Tyrone; and Mg-Fe-carbonate outcrops at Comanche in the Columbia Hills [1-4]. Here, we focus on using thermochemical modeling to understand the secondary alteration mineralogy at the Home Plate outcrop and surrounding Columbia Hills region in Gusev Crater. We use CHILLER [5] to evaluate mineral assemblages that are likely to form from the Martian Home Plate, Barn-Hill class rock Fastball in contact with a dilute fluid at various pressures, temperatures, and water-rock ratios. For details see [6]. In our models, hematite dominates the alteration assemblage at high W/R at 150°C, but is generally produced at W/R above 10. Goethite only forms at low temperature and W/R above 40 with a maximum around 100 and again around 100,000. Pyrite is produced at all temperatures but only at relatively high W/R. These results imply intermediate to high W/R and low to intermediate temperatures during alteration of the Home Plate region. Additional acidic brine, while not strictly excluded, is not required to form many of the observed phases. In contrast, the phyllosilicates recently invoked from orbital observations [4] indicate neutral to alkaline conditions - either accompanying the silica precipitation or as a separate event. For future exploration, our results emphasize that the observation of assemblages is critically important to understand mineral formation conditions and that minor phases

  17. Metamorphic sole formation and early plate interface rheology: Insights from Griggs apparatus experiments

    NASA Astrophysics Data System (ADS)

    Soret, Mathieu; Agard, Philippe; Dubacq, Benoît; Hirth, Greg; Yamato, Philippe; Ildefonse, Benoît; Prigent, Cécile

    2016-04-01

    800°C with confining pressure of 2 GPa. Another simple-shear experiment has been carried out at 800°C and 1 GPa with fined-grained natural garnet. With the aim of mimicking the early slab interface (between the metamorphic sole and banded peridotites at the base of the ophiolite), 2 simple-shear deformation experiments with 2 layers have been carried out at 800°C and confining pressure of 1 GPa. The bottom layer was made of hydrated basalt powder and the top layer was made of olivine. Fined-grained garnet-free amphibolite is significantly weaker than dunite but the appearance of harder minerals in the amphibolite (garnet and clinopyroxene) has major implications on its rheological evolution. These results allow liking field observations of strain localization at the interface to the metamorphic sole formation.

  18. Fuel swelling and interaction layer formation in the SELENIUM Si and ZrN coated U(Mo) dispersion fuel plates irradiated at high power in BR2

    NASA Astrophysics Data System (ADS)

    Leenaers, A.; Van den Berghe, S.; Koonen, E.; Kuzminov, V.; Detavernier, C.

    2015-03-01

    In the framework of the SELENIUM project two full size flat fuel plates were produced with respectively Si and ZrN coated U(Mo) particles and irradiated in the BR2 reactor at SCK•CEN. Non-destructive analysis of the plates showed that the fuel swelling profiles of both SELENIUM plates were very similar to each other and none of the plates showed signs of pillowing or excessive swelling at the end of irradiation at the highest power position (local maximum 70% 235U). The microstructural analysis showed that the Si coated fuel has less interaction phase formation at low burn-up but at the highest burn-ups, defects start to develop on the IL-matrix interface. The ZrN coated fuel, shows a virtual absence of reaction between the U(Mo) and the Al, up to high fission densities after which the interaction layer formation starts and defects develop in the matrix near the U(Mo) particles. It was found and is confirmed by the SELENIUM (Surface Engineering of Low ENrIched Uranium-Molybdenum) experiment that there are two phenomena at play that need to be controlled: the formation of an interaction layer and swelling of the fuel. As the interaction layer formation occurs at the U(Mo)-matrix interface, applying a diffusion barrier (coating) at that interface should prevent the interaction between U(Mo) and the matrix. The U(Mo) swelling, observed to proceed at an accelerating rate with respect to fission density accumulation, is governed by linear solid state swelling and fission gas bubble swelling due to recrystallization of the fuel. The examination of the SELENIUM fuel plates clearly show that for the U(Mo) dispersion fuel to be qualified, the swelling rate at high burn-up needs to be reduced.

  19. Formation of aerial standing wave field using ultrasonic sources consisting of multiple stripe-mode transverse vibrating plates

    NASA Astrophysics Data System (ADS)

    Naito, Koki; Asami, Takuya; Miura, Hikaru

    2015-07-01

    Intense aerial acoustic waves can be produced by an ultrasonic source consisting of a transverse vibrating plate and an external jutting driving point. Previously, we studied the dimensional parameters of vibrating plates to produce stripe-mode patterns and thereby determine the plate dimensions that generate high-quality patterns. In this research, we use four transverse vibrating plates as ultrasonic sources to produce intense standing wave fields in air. As a result, an aerial standing wave field was formed in the field surrounded by four vibrating plates. Furthermore, for a total input power of 30 W for the two ultrasonic sources, a very strong (sound pressure level, 167 dB) wave field is obtained.

  20. A comparative study of biofilm formation by Shiga toxigenic Escherichia coli using epifluorescence microscopy on stainless steel and a microtitre plate method.

    PubMed

    Rivas, Lucia; Dykes, Gary A; Fegan, Narelle

    2007-04-01

    Attachment of Shiga toxigenic Escherichia coli (STEC) to surfaces and the formation of biofilms may enhance persistence in a food processing environment and present a risk of contaminating products. Seven strains of STEC and three non-STEC strains were selected to compare two biofilm quantification methods; epifluorescence microscopy on stainless steel (SS) and a microtitre plate assay. The influence of prior growth in planktonic (nutrient broth) and sessile (nutrient agar) culture on biofilm production, as well as expression of surface structures and the possession of antigen 43 (encoded by agn43) on biofilm formation were also investigated. Biofilms were produced in diluted nutrient broth at 25 degrees C for 24 and 48 h. Curli expression was determined using congo red indicator agar, while the presence of agn43 was determined using polymerase chain reaction. No correlation was found between counts for epifluorescence microscopy on SS and the absorbance values obtained with the microtitre plate method for planktonic and sessile grown cultures. Different abilities of individual STEC strains to attach to SS and microtitre plates were found with some strains attaching better to each surface following growth in either planktonic or sessile culture. All O157 STEC strains had low biofilm counts on SS for planktonic and sessile grown cultures; however, one STEC O157:H- strain (EC516) had significantly greater (p<0.05) biofilm production on microtitre plates compared to the other O157 STEC strains. EC516 and other STEC (O174:H21 and O91:H21) strains expressing curli fimbriae were found to produce significantly greater (p<0.05) biofilms on microtitre plates compared to the non-curli expressing strains. No relationship was found between the production of type-I fimbriae, motility, agn43 and bacterial physicochemical properties (previously determined) and biofilm formation on SS or microtitre plates. Variations between the two biofilm determination methods may suggest that

  1. Innovative design of composite structures: The use of curvilinear fiber format to improve buckling resistance of composite plates with central circular holes

    NASA Technical Reports Server (NTRS)

    Hyer, M. W.; Lee, H. H.

    1990-01-01

    The gains in buckling performance are explored that can be achieved by deviating from the conventional straightline fiber format and considering the situation whereby the fiber orientation in a layer, or a group of layers, can vary from point to point. The particular situation studied is a simply supported square plate with a centrally located hole loaded in compression. By using both a sensitivity analysis and a gradient-search technique, fiber orientation in a number of regions of the plate are selected so as to increase the buckling load relative to baseline straightline designs. The sensitivity analysis is used to determine which regions of the plate have the most influence on buckling load, and the gradient search is used to find the design that is believed to represent the absolute maximum buckling load for the conditions prescribed. Convergence studies and sensitivity of the final design are discussed. By examining the stress resultant contours, it is shown how the curvilinear fibers move the load away from the unsupported hole region of the plate to the supported edges, thus increasing the buckling capacity. The tensile capacity of the improved buckling design is investigated, and it is shown that both tensile capacity and buckling capacity can be improved with the curvilinear fiber concept.

  2. Conditional Deletion of Indian Hedgehog in Limb Mesenchyme Results in Complete Loss of Growth Plate Formation but Allows Mature Osteoblast Differentiation.

    PubMed

    Amano, Katsuhiko; Densmore, Michael J; Lanske, Beate

    2015-12-01

    Indian hedgehog (Ihh) is widely recognized as an essential factor for proper skeletal development. Previous in vivo studies using mutant Ihh mouse models were limited by perinatal lethality or carried out after a growth plate formed. Thus the important role of Ihh in mesenchymal cell differentiation has not been investigated. In this study, we established Prx1-Cre;Ihh(fl/fl) mice to ablate Ihh specifically in limb mesenchyme to allow us to observe the phenotype continuously from prenatal development to 3 weeks of age. Mutant mice displayed severe limb abnormalities characterized by complete lack of secondary ossification center and growth plate, indicating an essential role for Ihh in the development of these structures. Interestingly, we discovered that osteoblast differentiation and bone formation could occur in conditions of deficient Ihh. This is a novel finding that has not been observed because of the early lethality of previous Ihh mutants. Mature osteoblasts expressing osteocalcin could be detected in the center of mutant bones at postnatal day 10 (P10). Osteoclasts and blood vessel formation were also present, suggesting active bone remodeling. Histomorphometric analyses show a significant increase in osteoclast number with no major changes in bone formation rate at 3 weeks of age. Mutant long bones in the limbs were deformed, with cortices comprised of irregular woven bone. Also, there was a marked decrease in gene expression of osteoblastic and osteocytic markers. Moreover, mutant long bones displayed bone dysplasia in which we observed increased osteoclast activity and partially reduced osteoblastic and osteocytic differentiation that lead ultimately to loss of bone structures at 3 weeks of age. In summary, our data show for the first time, the presence of mature osteoblasts in long bones of the limbs despite the complete loss of growth plate formation due to Ihh deficiency. These data indicate an important function for Ihh in regulating limb

  3. SNW1 is a critical regulator of spatial BMP activity, neural plate border formation, and neural crest specification in vertebrate embryos.

    PubMed

    Wu, Mary Y; Ramel, Marie-Christine; Howell, Michael; Hill, Caroline S

    2011-01-01

    Bone morphogenetic protein (BMP) gradients provide positional information to direct cell fate specification, such as patterning of the vertebrate ectoderm into neural, neural crest, and epidermal tissues, with precise borders segregating these domains. However, little is known about how BMP activity is regulated spatially and temporally during vertebrate development to contribute to embryonic patterning, and more specifically to neural crest formation. Through a large-scale in vivo functional screen in Xenopus for neural crest fate, we identified an essential regulator of BMP activity, SNW1. SNW1 is a nuclear protein known to regulate gene expression. Using antisense morpholinos to deplete SNW1 protein in both Xenopus and zebrafish embryos, we demonstrate that dorsally expressed SNW1 is required for neural crest specification, and this is independent of mesoderm formation and gastrulation morphogenetic movements. By exploiting a combination of immunostaining for phosphorylated Smad1 in Xenopus embryos and a BMP-dependent reporter transgenic zebrafish line, we show that SNW1 regulates a specific domain of BMP activity in the dorsal ectoderm at the neural plate border at post-gastrula stages. We use double in situ hybridizations and immunofluorescence to show how this domain of BMP activity is spatially positioned relative to the neural crest domain and that of SNW1 expression. Further in vivo and in vitro assays using cell culture and tissue explants allow us to conclude that SNW1 acts upstream of the BMP receptors. Finally, we show that the requirement of SNW1 for neural crest specification is through its ability to regulate BMP activity, as we demonstrate that targeted overexpression of BMP to the neural plate border is sufficient to restore neural crest formation in Xenopus SNW1 morphants. We conclude that through its ability to regulate a specific domain of BMP activity in the vertebrate embryo, SNW1 is a critical regulator of neural plate border formation and

  4. The Role of Hox in Pisiform and Calcaneus Growth Plate Formation and the Nature of the Zeugopod/Autopod Boundary.

    PubMed

    Reno, Philip L; Kjosness, Kelsey M; Hines, Jasmine E

    2016-07-01

    The mesopodium forms at the boundary between the zeugopod and autopod and is composed of short nodular bones that typically lack growth plates. Hoxa11 and Hoxa13 are expressed in mutually exclusive proximal-distal domains that demarcate the zeugopod/autopod boundary. Similarly, Hoxd genes are deployed in two distinct phases during limb development. The early phase corresponds to proximal segments including the zeugopod, and a late phase occurs in the digits. This arrangement produces a gap of low Hoxd expression that is traditionally viewed to correspond to the mesopodium. In contrast to the other mesopodials, the mammalian pisiform and calcaneus form true growth plates. We show that these bones, along with other proximal mesopodials, develop within the Hoxa11 and Hoxd11 expression domains. We also observe that the pisiform growth plate becomes disorganized with Hoxa11 or Hoxd11 loss of function, indicating a direct role for Hox11 in its development. Hoxa13 loss of function has minimal effect on the pisiform and proximal calcaneus as these bones still form secondary centers and undergo longitudinal growth. Consideration of the phenotypes resulting from hypodactyly (Hd) and synpolydactyly homolog (spdh) mutations, which result from altered HOXA13 and HOXD13 proteins, respectively, confirms that Hox13 plays a limited role in the development of the pisiform and calcaneus and suggests that they lie within the early phase of Hox expression. Therefore, with respect to patterns of ossification and gene expression, these bones share much more in common with the zeugopod than the autopod. Such an interpretation fits with the timing of autopod origins during tetrapod evolution.

  5. Quantum dot immunoassays in renewable surface column and 96-well plate formats for the fluorescence detection of Botulinum neurotoxin using high-affinity antibodies

    SciTech Connect

    Warner, Marvin G.; Grate, Jay W.; Tyler, Abby J.; Ozanich, Richard M.; Miller, Keith D.; Lou, Jianlong; Marks, James D.; Bruckner-Lea, Cindy J.

    2009-09-01

    A fluorescence sandwich immunoassay using high affinity antibodies and quantum dot (QD) reporters has been developed for detection of botulinum toxin serotype A (BoNT/A). For the development of the assay, a nontoxic recombinant fragment of the holotoxin (BoNT/A-HC-fragment) has been used as a structurally valid simulant for the full toxin molecule. The antibodies used, AR4 and RAZ1, bind to nonoverlapping epitopes present on both the full toxin and on the recombinant fragment. In one format, the immunoassay is carried out in a 96-well plate with detection in a standard plate reader. Detection down to 31 pM of the BoNT/Hc-fragment was demonstrated with a total incubation time of 3 hours, using AR4 as the capture antibody and QD-coupled RAZ1 as the reporter. In a second format, the AR4 capture antibody was coupled to Sepharose beads, and the immunochemical reactions were carried out in microcentrifuge tubes with an incubation time of 1 hour. These beads were subsequently captured and concentrated in a rotating rod “renewable surface” flow cell as part of a sequential injection fluidic system. This flow cell was equipped with a fiber optic system for fluorescence measurements. In PBS buffer solution matrix, the BoNT/A-HC-fragment was detected to concentrations as low as 5 pM using the fluidic measurement approach.

  6. A new platform for electrochemical analysis of a microtiter plate

    NASA Astrophysics Data System (ADS)

    Allen, Brian P.; Gilbert, Richard J.; Zhou, Xiao-Feng

    2004-12-01

    A disposable device is described for use in High Content Screening within the drug research process; it interfaces with a standard 384 well microtiter plate providing simultaneous full kinetic reaction data for a complete row of 24 wells. The device can be used in secondary screening for lead optimisation, for ADME (Absorption Distribution Metabolism and Excretion) assessment and toxicological assessment of candidate compounds. The device is a microfluidic unit and incorporates the necessary substrate and reaction chemicals. The microfluidic circuitry includes mixing paths, a reaction chamber, a single use valve and a waste reservoir as well as electrical measurement contacts. Movement of the fluids is provided by a single vacuum line which is distributed to all 24 separate cells. The device described incorporates a self-validation technique which provides a built in test facility.

  7. Plate motion

    SciTech Connect

    Gordon, R.G. )

    1991-01-01

    The motion of tectonic plates on the earth is characterized in a critical review of U.S. research from the period 1987-1990. Topics addressed include the NUVEL-1 global model of current plate motions, diffuse plate boundaries and the oceanic lithosphere, the relation between plate motions and distributed deformations, accelerations and the steadiness of plate motions, the distribution of current Pacific-North America motion across western North America and its margin, plate reconstructions and their uncertainties, hotspots, and plate dynamics. A comprehensive bibliography is provided. 126 refs.

  8. Formation of {beta}-nickel hydroxide plate-like structures under mild conditions and their optical properties

    SciTech Connect

    Moura, A.P. de; Lima, R.C.; Paris, E.C.; Li, M.S.; Varela, J.A.; Longo, E.

    2011-10-15

    Nanostructural {beta}-nickel hydroxide ({beta}-Ni(OH){sub 2}) plates were prepared using the microwave-hydrothermal (MH) method at a low temperature and short reaction times. An ammonia solution was employed as the coordinating agent, which reacts with [Ni(H{sub 2}O){sub 6}]{sup 2+} to control the growth of {beta}-Ni(OH){sub 2} nuclei. A trigonal {beta}-Ni(OH){sub 2} single phase was observed by X-ray diffraction (XRD) analyses, and the crystal cell was constructed with structural parameters and atomic coordinates obtained from Rietveld refinement. Field emission scanning electron microscopy (FE-SEM) images revealed that the samples consisted of hexagonal-shaped nanoplates with a different particle size distribution. Broad absorption bands assigned as transitions of Ni{sup 2+} in oxygen octahedral sites were revealed by UV-vis spectra. Photoluminescence (PL) properties observed with a maximum peak centered in the blue-green region were attributed to different defects, which were produced during the nucleation process. We present a growth process scheme of the {beta}-Ni(OH){sub 2} nanoplates. - Graphical abstract: Nanostructural {beta}-Ni(OH){sub 2} crystalline powders were prepared by rapid microwave-hydrothermal method for 1, 8 and 32 min. The hexagonal-shaped nanoplates obtained presented PL emission in the blue-green region and each decomposed component represents a different type of electronic transition, which can be linked to the structural arrangement or surface defects. Highlights: > Ammonia solution to control the growth of {beta}-Ni(OH){sub 2} nuclei. > Regular plates-shape related to crystallization-dissolution-recrystallization. > The surface states and lattice defects generated in growth mechanism of crystals. > Different defects produced in the growth process responsible by photoluminescence. > Each component of photoluminescence curve linked to structural arrangement or surface defects.

  9. Fluorescence lifetime plate reader: resolution and precision meet high-throughput.

    PubMed

    Petersen, Karl J; Peterson, Kurt C; Muretta, Joseph M; Higgins, Sutton E; Gillispie, Gregory D; Thomas, David D

    2014-11-01

    We describe a nanosecond time-resolved fluorescence spectrometer that acquires fluorescence decay waveforms from each well of a 384-well microplate in 3 min with signal-to-noise exceeding 400 using direct waveform recording. The instrument combines high-energy pulsed laser sources (5-10 kHz repetition rate) with a photomultiplier and high-speed digitizer (1 GHz) to record a fluorescence decay waveform after each pulse. Waveforms acquired from rhodamine or 5-((2-aminoethyl)amino) naphthalene-1-sulfonic acid dyes in a 384-well plate gave lifetime measurements 5- to 25-fold more precise than the simultaneous intensity measurements. Lifetimes as short as 0.04 ns were acquired by interleaving with an effective sample rate of 5 GHz. Lifetime measurements resolved mixtures of single-exponential dyes with better than 1% accuracy. The fluorescence lifetime plate reader enables multiple-well fluorescence lifetime measurements with an acquisition time of 0.5 s per well, suitable for high-throughput fluorescence lifetime screening applications.

  10. On the actual variety of plate dynamical mechanisms and how mantle evolution affected them through time, from core formation to the Indian collision

    NASA Astrophysics Data System (ADS)

    Osmaston, Miles

    2010-05-01

    If horizontal plate motions were driven by thermal convection of the mantle, they would display the action of slow-to-change body forces. Yet rapid changes of spreading rate and direction, and ridge jumps, are well-documented for the past 130Ma. Also convection cannot readily cause rotations of a plate (e.g. Africa) about a pole within the plate or near it. And plate motions, especially that of India, scarcely fit a convective pattern. To address these problems we look first at mantle motivation at both ends of earth history, beginning with core formation. I then introduce 3 important properties of mantle materials, whose neglect by mantle modellers has surely impaired the value of their work, but whose recognition illuminates the present plate dynamical situation and provides the Earth with a heat engine that is not thermal convection. Finally I sketch the intervening changes in behaviour over time, the sharpest of which brought about the rise of atmospheric oxygen at ~2.25Ga. Core formation. As the very high specific angular momentum of mean planetary material (>105-fold relative to solar) can only be achieved if the planets were wholly accreted in presence of the nebula [1], the iron percolation model is ruled out, because it takes too long. This validates the A.E.Ringwood model (1960-1978) involving nebular H reaction with erupting FeO. The iron then loads the downgoing limb of what is then not a truly thermal convection system. Huge volumes of reaction water were produced, giving the early Earth a wet mantle, a (diminishing) feature that we'll see has constrained mantle behaviour ever since. Plate dynamics since 150Ma. Multiple plate dynamical evidence [2], which will be rapidly re-presented here, shows that currently (a) the Earth has a 2-layer mantle system with a boundary at ~660km and (b) that most cratons have tectospheric keels that reach right to that boundary, or nearly so. The argument is the simple and persuasive one (even to seismologists) of mantle

  11. The spatial and temporal expression of VEGF and its receptors 1 and 2 in post-traumatic bone bridge formation of the growth plate.

    PubMed

    Fischerauer, Eva; Heidari, Nima; Neumayer, Bernhard; Deutsch, Alexander; Weinberg, Annelie M

    2011-12-01

    Injuries to growth plates may initiate the formation of reversible or irreversible bone-bridges, may leading to bone length discrepancy or axis deviation. As vascular invasion is essential for the formation of bone tissue, the aim of our study was to investigate the kinetic expression of Vascular Endothelial Growth Factor (VEGF) and its receptors R1 and R2 and the ingrowth of vessels in the formation of bone bridges in a rat physeal injury model. Quantitative Real-Time Polymerase Chain Reaction was performed for VEGF and its receptors. Samples from the proximal physis of the tibial bone were immunohistochemically evaluated for the expression of VEGF and its R1 and R2 receptors and Laminin. Morphologically, physeal bone bridge formation was validated by means of Magnetic Resonance Imaging. Kinetic expression of VEGF and VEGF-R1 mRNA documented a tendency towards an increase in expression on day 7. Histological analyses showed a hematoma containing bone debris on day 1 which was replaced with bony trabeculae by day 14, forming a bone bridge by day 28 which was preceded and accompanied by angiogenesis and consistent with MRI data. VEGF and VEGF-R2 was expressed on the debris within the hematoma and bone trabeculae from days 1 to 28. VEGF-R1 expression was only noted until day 14. The findings of our study suggest that physeal bone bridge formation is in part triggered by VEGF expression and associated with angiogenesis, which was shown to precede bone bridge formation and may be further stimulated through VEGF-positive bone debris.

  12. Actively evolving microplate formation by oblique collision and sideways motion along strike-slip faults: An example from the northeastern Caribbean plate margin

    NASA Astrophysics Data System (ADS)

    Mann, Paul; Taylor, F. W.; Edwards, R. Lawrence; Ku, Teh-Lung

    1995-06-01

    The pattern of folding, faulting, and late Quaternary coral-reef uplift rates in western and central Hispaniola (Haiti and Dominican Republic) suggest that the elongate Gonave microplate, a 190,000-km 2 area of the northeastern Caribbean plate, is in the process of shearing off the Caribbean plate and accreting to the North American plate. Late Cenozoic transpression between the southeastern Bahama Platform and the Caribbean plate in Hispaniola has inhibited the eastward motion of the northeastern corner of the plate. Transpression is manifested in western and central Hispaniola by the formation of regional scale folds that correspond to present-day, anticlinal topographic mountain chains continuous with offshore anticlinal ridges. Areas of most rapid Quaternary uplift determined from onland coral reefs 125 ka and younger, coincide with the axial traces of these folds. Offshore data suggest recent folding and faulting of the seafloor. Onshore reef data do not conclusively require late Quaternary folding, but demonstrate that tectonic uplift rates of the axial areas of the anticlines decrease from the Northwest Peninsula of Haiti (0.37 mm/yr) to to the central part of the coast of western Haiti (0.19 mm/yr) to the south-central part of western Haiti (0 mm/yr). Formation of the 1200-km-long Enriquillo-Plantain Garden-Walton fault zone as a 'bypass' strike-slip fault has isolated the southern edge of the Gonave microplate and is allowing continued, unimpeded eastward motion of a smaller Caribbean plate past the zone of late Neogene convergence and Quaternary uplift of coral reefs in Hispaniola. Offshore seismic reflection data from the Jamaica Passage, the marine strait separating Jamaica and Haiti, show that the Enriquillo-Plantain Garden fault zone forms a narrow but deep, active fault-bounded trough beneath the passage. The active fault is continuous with active faults mapped onshore in western Haiti and eastern Jamaica; the bathymetric deep is present because the

  13. Arabidopsis CSLD5 Functions in Cell Plate Formation in a Cell Cycle-Dependent Manner[OPEN

    PubMed Central

    2016-01-01

    In plants, the presence of a load-bearing cell wall presents unique challenges during cell division. Unlike other eukaryotes, which undergo contractile cytokinesis upon completion of mitosis, plants instead synthesize and assemble a new dividing cell wall to separate newly formed daughter cells. Here, we mine transcriptome data from individual cell types in the Arabidopsis thaliana stomatal lineage and identify CSLD5, a member of the Cellulose Synthase Like-D family, as a cell wall biosynthesis enzyme uniquely enriched in rapidly dividing cell populations. We further show that CSLD5 is a direct target of SPEECHLESS, the master transcriptional regulator of these divisions during stomatal development. Using a combination of genetic analysis and in vivo localization of fluorescently tagged fusion proteins, we show that CSLD5 preferentially accumulates in dividing plant cells where it participates in the construction of newly forming cell plates. We show that CSLD5 is an unstable protein that is rapidly degraded upon completion of cell division and that the protein turnover characteristics of CSLD5 are altered in ccs52a2 mutants, indicating that CSLD5 turnover may be regulated by a cell cycle-associated E3-ubiquitin ligase, the anaphase-promoting complex. PMID:27354558

  14. Partial Melt Systems in Plate-Driven Corner Flow: Evaluating the Formation of Porosity Bands as a Mechanism for Magma Focusing at Mid-Ocean Ridges

    NASA Astrophysics Data System (ADS)

    Gebhardt, D.; Butler, S. L.

    2015-12-01

    The imposition of an external shear on a system of partial melt will result in compaction of the solid matrix and concentration of the interstitial liquid melt leading to the formation of regions of contrasting high and low porosity. In experiments, direct and torsional shear geometries have demonstrated that these regions of varying porosity form in bands orientated at low angles relative to the shear plane. A variety of numerical models have been employed to recreate these experimental results. Simple shear, pure shear and torsional shear geometries have been used in both linear and nonlinear numerical settings to model the formation of the porosity bands. In this contribution the numerical models utilize a shear geometry derived from the velocity field of the plate-driven corner flow of a mid-ocean ridge. Motivation for using the velocity field of a mid-ocean ridge comes from evidence that suggests the existence of lateral melt channeling from either side of the ridge axis. Imposing the shear from a mid-ocean ridge corner flow allows for the evaluation of the resulting porosity bands in terms of suitability for channeling melt laterally toward the ridge axis. This is done using both slow and fast spreading ridge geometries. The degree of similarity between previous numerical and experimental results has been found to be greatly influenced by the imposed viscosity law of the solid matrix phase. In order to keep this in mind, the numerical models in this contribution use three different matrix viscosity laws: strain-rate independent, strain-rate dependent and anisotropic. Of these rheologies, strain-rate independence results in the poorest orientation for channeling melt directly to the ridge axis. The strain-rate dependent and anisotropic viscosities present more favorable direct-channeling orientations for the fastest growing porosity bands, but in both cases the background flow will rotate bands to less ideal orientations over time. However, these less

  15. Development of a Scalable, High-Throughput-Compatible Assay to Detect Tau Aggregates Using iPSC-Derived Cortical Neurons Maintained in a Three-Dimensional Culture Format.

    PubMed

    Medda, X; Mertens, L; Versweyveld, S; Diels, A; Barnham, L; Bretteville, A; Buist, A; Verheyen, A; Royaux, I; Ebneth, A; Cabrera-Socorro, A

    2016-09-01

    Tau aggregation is the pathological hallmark that best correlates with the progression of Alzheimer's disease (AD). The presence of neurofibrillary tangles (NFTs), formed of hyperphosphorylated tau, leads to neuronal dysfunction and loss, and is directly associated with the cognitive decline observed in AD patients. The limited success in targeting β-amyloid pathologies has reinforced the hypothesis of blocking tau phosphorylation, aggregation, and/or spreading as alternative therapeutic entry points to treat AD. Identification of novel therapies requires disease-relevant and scalable assays capable of reproducing key features of the pathology in an in vitro setting. Here we use induced pluripotent stem cells (iPSCs) as a virtually unlimited source of human cortical neurons to develop a robust and scalable tau aggregation model compatible with high-throughput screening (HTS). We downscaled cell culture conditions to 384-well plate format and used Matrigel to introduce an extra physical protection against cell detachment that reduces shearing stress and better recapitulates pathological conditions. We complemented the assay with AlphaLISA technology for the detection of tau aggregates in a high-throughput-compatible format. The assay is reproducible across users and works with different commercially available iPSC lines, representing a highly translational tool for the identification of novel treatments against tauopathies, including AD. PMID:26984927

  16. The formation of a hybrid structure from tungsten selenide and oxide plates for a hydrogen-evolution electrocatalyst

    NASA Astrophysics Data System (ADS)

    Fominski, V. Yu.; Grigoriev, S. N.; Romanov, R. I.; Volosova, M. A.; Grunin, A. I.; Teterina, G. D.

    2016-06-01

    It has been found that the pulsed laser deposition of a thin tungsten selenide film, followed by thermal treatment at 550°C in an Ar + O2 mixture of gases, results in the formation of a hybrid structure that is made up of ultrathin WSe2 and WO3- y platelets. The structural and size characteristics of the nanoplatelets deposited on microcrystalline graphite provide the effective hydrogen evolution reaction in a 0.5 M H2SO4 solution, with the cathode current made about seven times higher at a potential of-100 mV and the slope of the Tafel characteristic reduced from 340 to 90 mV/dec.

  17. A new approach to the application of solid phase extraction disks with LC-MS/MS for the analysis of drugs on a 96-well plate format.

    PubMed

    Cudjoe, Erasmus; Pawliszyn, Janusz

    2009-11-01

    A new 96-well disk solid phase extraction sample preparation technique which does not involve vacuum pumps integrated with liquid chromatographic tandem mass spectrometric (LC-MS/MS) was developed for high throughput determination of benzodiazepines (nordiazepam, diazepam, lorazepam and oxazepam). In addition, the method completely allows the re-use of the SPE disk membranes for subsequent analyses after re-conditioning. The method utilizes a robotic autosampler for parallel extractions in a 96-well plate format. Results have been presented for independent extractions from three matrices; phosphate buffer solution, urine, and plasma. Factors affecting data reproducibility, extraction kinetics, sample throughput, and reliability of the system were investigated and optimized. A total time required per sample was 0.94 min using 96-well format. Method reproducibility was < or =9% relative standard deviation for all three matrices. Limits of detection and quantitation recorded were respectively in the range 0.02-0.15 and 0.2-2.0 ng/mL with linearity ranging from 0.2 to 500 ng/mL for all matrices.

  18. The innermost chorionic layer of Drosophila. I. The role of chorin octamers in the formation of a family of interdigitating crystalline plates.

    PubMed

    Akey, C W; Edelstein, S J

    1987-02-20

    The innermost chorionic layer (ICL) within egg shells of Drosophila melanogaster is composed of thin, abutting three-dimensional crystalline plates which form a closed, membrane-like sheath. Collectively, the crystals within the sheath appear to form a family of related three-dimensional crystals in space group C222; however, specimens prepared for electron microscopy are actually two-dimensional crystals in c222. The projected structures of the negatively stained crystals have been studied by minimal dose electron microscopy employing image reconstruction methods. Thin sections indicate that unit cells within the ICL are composed of paired layers; top and bottom layers are related by centrally located 2-fold axes, aligned parallel to the surface of the ICL. The most probable structural unit of the crystals is a tetramer of chorin dimers with a point group symmetry of 222, which is denoted a chorin octamer. Projection maps were computed from average transforms of two-dimensional crystals for delta (the primitive unit cell angle) equal to 84 degrees, 90 degrees and 97 degrees (+/- 1.5 degrees). The maps indicate that the molecular transitions responsible for the observed family of crystals involve concerted intramolecular rearrangements about molecular 2-fold axes. The significance in vivo of the family of crystals within the ICL is not known; however, structural considerations suggest that the observed polymorphism may reflect one facet of an intrinsic bonding flexibility of the ICL octamer that may play a role in the formation of interplate junctions and the assembly of a continuous closed sheath. The ICL may therefore serve as a structural bridge between the vitelline membrane-wax layer and the endochondrial floor, allowing the larva to shed the inner egg shell layers during hatching.

  19. A kinematic model for the formation of the Siletz-Crescent forearc terrane by capture of coherent fragments of the Farallon and Resurrection plates

    USGS Publications Warehouse

    McCrory, Patricia A.; Wilson, Douglas S.

    2013-01-01

    The volcanic basement of the Oregon and Washington Coast ranges has been proposed to represent a pair of tracks of the Yellowstone hotspot formed at a mid-ocean ridge during the early Cenozoic. This interpretation has been questioned on many grounds, especially that the range of ages does not match the offshore spreading rates and that the presence of continental coarse clastic sediments is difficult to reconcile with fast convergence rates between the oceanic plates and North America. Updates to basement geochronology and plate motion history reveal that these objections are much less serious than when they were first raised. Forward plate kinematic modeling reveals that predicted basement ages can be consistent with the observed range of about 55–49 Ma, and that the entire basement terrane can form within about 300 km of continental sources for clastic sediments. This kinematic model indicates that there is no firm reason to reject the near-ridge hotspot hypothesis on the basis of plate motions. A novel element of the model is the Resurrection plate, previously proposed to exist between the Farallon and Kula plates. By including the defunct Resurrection plate in our reconstruction, we are able to model the Farallon hotspot track as docking against the Oregon subduction margin starting about 53 Ma, followed by docking of the Resurrection track to the north starting about 48 Ma. Accretion of the Farallon plate fragment and partial subduction of the Resurrection fragment complicates the three-dimensional structure of the modern Cascadia forearc. We interpret the so-called “E” layer beneath Vancouver Island to be part of the Resurrection fragment. Our new kinematic model of mobile terranes within the Paleogene North American plate boundary allows reinterpretation of the three-dimensional structure of the Cascadia forearc and its relationship to ongoing seismotectonic processes.

  20. Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA.

    PubMed

    Saitta, Evan Thomas

    2015-01-01

    Conclusive evidence for sexual dimorphism in non-avian dinosaurs has been elusive. Here it is shown that dimorphism in the shape of the dermal plates of Stegosaurus mjosi (Upper Jurassic, western USA) does not result from non-sex-related individual, interspecific, or ontogenetic variation and is most likely a sexually dimorphic feature. One morph possessed wide, oval plates 45% larger in surface area than the tall, narrow plates of the other morph. Intermediate morphologies are lacking as principal component analysis supports marked size- and shape-based dimorphism. In contrast, many non-sex-related individual variations are expected to show intermediate morphologies. Taphonomy of a new quarry in Montana (JRDI 5ES Quarry) shows that at least five individuals were buried in a single horizon and were not brought together by water or scavenger transportation. This new site demonstrates co-existence, and possibly suggests sociality, between two morphs that only show dimorphism in their plates. Without evidence for niche partitioning, it is unlikely that the two morphs represent different species. Histology of the new specimens in combination with studies on previous specimens indicates that both morphs occur in fully-grown individuals. Therefore, the dimorphism is not a result of ontogenetic change. Furthermore, the two morphs of plates do not simply come from different positions on the back of a single individual. Plates from all positions on the body can be classified as one of the two morphs, and previously discovered, isolated specimens possess only one morph of plates. Based on the seemingly display-oriented morphology of plates, female mate choice was likely the driving evolutionary mechanism rather than male-male competition. Dinosaur ornamentation possibly served similar functions to the ornamentation of modern species. Comparisons to ornamentation involved in sexual selection of extant species, such as the horns of bovids, may be appropriate in predicting the

  1. Evidence for Sexual Dimorphism in the Plated Dinosaur Stegosaurus mjosi (Ornithischia, Stegosauria) from the Morrison Formation (Upper Jurassic) of Western USA

    PubMed Central

    Saitta, Evan Thomas

    2015-01-01

    Conclusive evidence for sexual dimorphism in non-avian dinosaurs has been elusive. Here it is shown that dimorphism in the shape of the dermal plates of Stegosaurus mjosi (Upper Jurassic, western USA) does not result from non-sex-related individual, interspecific, or ontogenetic variation and is most likely a sexually dimorphic feature. One morph possessed wide, oval plates 45% larger in surface area than the tall, narrow plates of the other morph. Intermediate morphologies are lacking as principal component analysis supports marked size- and shape-based dimorphism. In contrast, many non-sex-related individual variations are expected to show intermediate morphologies. Taphonomy of a new quarry in Montana (JRDI 5ES Quarry) shows that at least five individuals were buried in a single horizon and were not brought together by water or scavenger transportation. This new site demonstrates co-existence, and possibly suggests sociality, between two morphs that only show dimorphism in their plates. Without evidence for niche partitioning, it is unlikely that the two morphs represent different species. Histology of the new specimens in combination with studies on previous specimens indicates that both morphs occur in fully-grown individuals. Therefore, the dimorphism is not a result of ontogenetic change. Furthermore, the two morphs of plates do not simply come from different positions on the back of a single individual. Plates from all positions on the body can be classified as one of the two morphs, and previously discovered, isolated specimens possess only one morph of plates. Based on the seemingly display-oriented morphology of plates, female mate choice was likely the driving evolutionary mechanism rather than male-male competition. Dinosaur ornamentation possibly served similar functions to the ornamentation of modern species. Comparisons to ornamentation involved in sexual selection of extant species, such as the horns of bovids, may be appropriate in predicting the

  2. Tectonics of the Easter plate

    NASA Technical Reports Server (NTRS)

    Engeln, J. F.; Stein, S.

    1984-01-01

    A new model for the Easter plate is presented in which rift propagation has resulted in the formation of a rigid plate between the propagating and dying ridges. The distribution of earthquakes, eleven new focal mechanisms, and existing bathymetric and magnetic data are used to describe the tectonics of this area. Both the Easter-Nazca and Easter-Pacific Euler poles are sufficiently close to the Easter plate to cause rapid changes in rates and directions of motion along the boundaries. The east and west boundaries are propagating and dying ridges; the southwest boundary is a slow-spreading ridge and the northern boundary is a complex zone of convergent and transform motion. The Easter plate may reflect the tectonics of rift propagation on a large scale, where rigid plate tectonics requires boundary reorientation. Simple schematic models to illustrate the general features and processes which occur at plates resulting from large-scale rift propagation are used.

  3. A High Sensitivity Micro Format Chemiluminescence Enzyme Inhibition Assay for Determination of Hg(II)

    PubMed Central

    Deshpande, Kanchanmala; Mishra, Rupesh K.; Bhand, Sunil

    2010-01-01

    A highly sensitive and specific enzyme inhibition assay based on alcohol oxidase (AlOx) and horseradish peroxidase (HRP) for determination of mercury Hg(II) in water samples has been presented. This article describes the optimization and miniaturization of an enzymatic assay using a chemiluminescence reaction. The analytical performance and detection limit for determination of Hg(II) was optimized in 96 well plates and further extended to 384 well plates with a 10-fold reduction in assay volume. Inhibition of the enzyme activity by dissolved Hg(II) was found to be linear in the range 5–500 pg·mL−1 with 3% CV in inter-batch assay. Due to miniaturization of assay in 384 well plates, Hg(II) was measurable as low as 1 pg·mL−1 within 15 min. About 10-fold more specificity of the developed assay for Hg(II) analysis was confirmed by challenging with interfering divalent metal ions such as cadmium Cd(II) and lead Pb(II). Using the proposed assay we could successfully demonstrate that in a composite mixture of Hg(II), Cd(II) and Pb(II), inhibition by each metal ion is significantly enhanced in the presence of the others. Applicability of the proposed assay for the determination of the Hg(II) in spiked drinking and sea water resulted in recoveries ranging from 100–110.52%. PMID:22163555

  4. Importance of the Small-Scale Processes Melting, Plate Boundary Formation and Mineralogy on the Large-Scale, Long-Term Thermo-Chemical Evolution of Earth's Mantle-Plate System

    NASA Astrophysics Data System (ADS)

    Tackley, P.

    2015-12-01

    Seismic observations of the deep Earth reveal the presence of two large low shear velocity provinces (LLSVPs) that are typically inferred to be dense chemically-distinct material, as well as discontinuities that are typically linked to the post-perovskite (pPv) phase transition. Several possible origins of chemically-dense material have been proposed, including recycling of mid-ocean ridge basalt (MORB), primordial differentiation events, crystallisation of a basal magma ocean, or some combination of these creating a basal melange (BAM; Tackley 2012 Earth Sci. Rev.). Each of these possibilities would result in a different composition hence different mineralogy. In order to constrain this we have been running calculations of thermo-chemical mantle evolution over 4.5 billion years that include melting-induced differentiation, plate tectonics induced by strongly temperature-dependent viscosity and plastic yielding, core cooling and compressibility with reasonable assumptions about the pressure-dependence of other material properties. Some of our simulations start from a magma ocean state so initial layering is developed self-consistently. Already-published results (Nakagawa et al., 2009 GCubed, 2010 PEPI, 2012 GCubed) already indicate the importance of exact MORB composition on the amount of MORB segregating above the CMB, which in turn influences mantle thermal structure and the evolution of the core and geodynamo. In more recent results we have been additionally including primordial material. We find that melting-induced differentiation has several first-order effects on the dynamics, including (i) making plate tectonics easier (through stresses associated with lateral variations in crustal thickness) and (ii) reducing heat flux through the CMB (due to the build-up of dense material above the CMB); also (iii) tectonic mode (continuous plate tectonics, episodic lid or stagnant lid) also makes a first-order difference to mantle structure and dynamics. This emphasises

  5. Formation of III–V ternary solid solutions on GaAs and GaSb plates via solid-phase substitution reactions

    SciTech Connect

    Vasil’ev, V. I.; Gagis, G. S. Kuchinskii, V. I.; Danil’chenko, V. G.

    2015-07-15

    Processes are considered in which ultrathin layers of III–V ternary solid solutions are formed via the delivery of Group-V element vapors to GaAs and GaSb semiconductor plates, with solid-phase substitution reactions occurring in the surface layers of these plates. This method can form defect-free GaAs{sup 1–x}P{sup x}, GaAs{sup x}Sb{sup 1–x}, and GaP{sup x}Sb{sup 1–x} layers with thicknesses of 10–20 nm and a content x of the embedded components of up to 0.04.

  6. The Hydrothermal System at Home Plate in Gusev Crater, Mars: Formation of High Silica Material by Acid-Sulfate Alteration of Basalt

    NASA Technical Reports Server (NTRS)

    Morris, R. V.; Ming, D. W.; Gellert, R.; Yen, A.; Clark, B. C.; Gnaff, T. G.; Arvidson, R. E.; Squyres, S. W.

    2008-01-01

    The Alpha Particle X-ray Spectrometer (APXS) instrument on the Mars Exploration Rover (MER) Spirit measured three targets on or adjacent to Home Plate in Gusev Crater that have unusually high SiO2 concentrations (68% to 91%), unusually low FeO concentrations (1% to 7%, with total Fe as FeO), and unusually high TiO2/FeO ratios (0.2 to 1.2 by weight) [1]. Two targets (Kenosha Comets and Lefty Ganote) are located on high albedo soil (Gertrude Weise) that was exposed by the rover wheels, and one target is a float rock called Fuzzy Smith. Kenosha Comets has the highest SiO2 concentration, lowest FeO concentration, and highest TiO2/FeO ratio. Mineralogical evidence from the MER Miniature Thermal Emission Spectrometer (Mini-TES) suggests that the SiO2 is present as amorphous (noncrystalline) SiO2 at Gertrude Weise and nearby targets [2,3]. Mini-TES data were not acquired for Fuzzy Smith. Home Plate is considered to have an explosive volcanic origin, resulting when basaltic magma came into contact with ground water or ice [4]. Within 50 m to 1 km of Home Plate are sulfate rich soil deposits (Paso Robles class soils with 22-35% SO3) which are considered to be probable fumarolic and/or hydrothermal deposits associated with the volcanism [5]. We develop the model here, suggested by [5], that the high-silica materials are another manifestation of acid-sulfate processes associated with fumarolic and hydrothermal activity at Home Plate. This is done by analogy with basaltic materials altered by acid sulfate processes on the Island of Hawaii.

  7. Healing of fractures with freeze-dried cortical bone plates. Comparison with compression plating.

    PubMed

    Malinin, T; Latta, L L; Wagner, J L; Brown, M D

    1984-11-01

    The healing of fractures of the radius with internal fixation by stainless-steel compression plates was compared with fractures fixed with freeze-dried bone-plate allografts. Fractures fixed with metallic plates gained slightly less than half the biomechanical strength of the contralateral control bone and healed without noticeable external callus formation. Bone-plated fractures regained three-fourths of the biomechanical strength of controls and healed by forming an external callus. Bone-plate allografts were eventually incorporated in the host bone. Allograft plates were vascularized and remodeled into cancellous bone in the process of incorporation in the host bones.

  8. The radiolarian evidence for the accretion of the Fu-saki Formation with the inferred oceanic plate stratigraphy: A case of weakly-metamorphosed accretionary complex in Ishigaki Jima, southern Ryukyu Arc, Japan

    NASA Astrophysics Data System (ADS)

    Nakae, Satoshi

    2013-09-01

    The island of Ishigaki Jima, located in the western part of the southern Ryukyu Arc, Japan, is underlain by a basement comprising the Tumuru and Fu-saki formations. The former is a pelitic glaucophane schist with a metamorphic age of 220-190 Ma, and the latter is a weakly metamorphosed accretionary complex, composed mainly of chert, mudstone and sandstone with minor amounts of limestone and mafic rocks. The Fu-saki Formation was weakly metamorphosed at ∼140 Ma. Latest Carboniferous-Early Jurassic microfossils have been obtained from the limestones, cherts and siliceous mudstones of this formation, but no fossils have been collected from the phyllitic mudstones. The radiolarian fauna of the phyllitic mudstones described herein indicates a late Pliensbachian-early Toarcian (Early Jurassic) age. This result, when combined with existing data, enables the reconstruction of an oceanic plate stratigraphy, showing a succession of (in ascending order) Upper Carboniferous-Triassic cherts, Sinemurian-lower Pliensbachian siliceous mudstones and upper Pliensbachian-lower Toarcian phyllitic mudstones and sandstones. The radiolarians from the phyllitic mudstones are important in constraining the timing of the accretion of the Fu-saki Formation to the base of the Tumuru Formation.

  9. Intermittent Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Silver, P. G.; Behn, M. D.

    2006-12-01

    prevent the ultimate closure of the Pacific basin and thus the cessation of subduction. More noteworthy is where subduction is not initiating. First, there is no evidence for subduction initiation anywhere within the Atlantic basin (excluding the Caribbean and Scotia), despite the mature 100-200 my age of passive-margin oceanic lithosphere. The formation of the Alpine-Himalayan chain represents the cessation of roughly 10,000 km of subduction at about 35-50 ma, Yet, no new subduction zones have initiated south of India or Africa, the two major continents that participated in the collision. These examples illustrate that subduction does not immediately initiate following a continent-continent collision, and may lag by 10s if not 100s of millions of years. The stoppage of plate tectonics, or even a dramatic reduction in subduction flux, would have significant thermal consequences for the mantle. It would effectively mark a temporary switch to "stagnant-lid" tectonics, analogous to that found on Venus, resulting in a significant increase in global mantle potential temperature (30- 100°C per 100 my) and a possibly widespread increase in magmatic activity. Such a hiatus may have occurred in the Mid-Proterozoic (1.1-1.6Ga), an era characterized by the virtual absence of orogenic activity, the longest-lived passive margin (600 My), and the production of enigmatic "anorogenic" granites found over thousands of kilometers in a belt presently stretching from southwestern to northeastern North America.

  10. MICROTUBULE-ASSOCIATED PROTEIN65 is essential for maintenance of phragmoplast bipolarity and formation of the cell plate in Physcomitrella patens.

    PubMed

    Kosetsu, Ken; de Keijzer, Jeroen; Janson, Marcel E; Goshima, Gohta

    2013-11-01

    The phragmoplast, a plant-specific apparatus that mediates cytokinesis, mainly consists of microtubules (MTs) arranged in a bipolar fashion, such that their plus ends interdigitate at the equator. Membrane vesicles are thought to move along the MTs toward the equator and fuse to form the cell plate. Although several genes required for phragmoplast MT organization have been identified, the mechanisms that maintain the bipolarity of phragmoplasts remain poorly understood. Here, we show that engaging phragmoplast MTs in a bipolar fashion in protonemal cells of the moss Physcomitrella patens requires the conserved MT cross-linking protein MICROTUBULE-ASSOCIATED PROTEIN65 (MAP65). Simultaneous knockdown of the three MAP65s expressed in those cells severely compromised MT interdigitation at the phragmoplast equator after anaphase onset, resulting in the collapse of the phragmoplast in telophase. Cytokinetic vesicles initially localized to the anaphase midzone as normal but failed to further accumulate in the next several minutes, although the bipolarity of the MT array was preserved. Our data indicate that the presence of bipolar MT arrays is insufficient for vesicle accumulation at the equator and further suggest that MAP65-mediated MT interdigitation is a prerequisite for maintenance of bipolarity of the phragmoplast and accumulation and/or fusion of cell plate-destined vesicles at the equatorial plane.

  11. MICROTUBULE-ASSOCIATED PROTEIN65 is essential for maintenance of phragmoplast bipolarity and formation of the cell plate in Physcomitrella patens.

    PubMed

    Kosetsu, Ken; de Keijzer, Jeroen; Janson, Marcel E; Goshima, Gohta

    2013-11-01

    The phragmoplast, a plant-specific apparatus that mediates cytokinesis, mainly consists of microtubules (MTs) arranged in a bipolar fashion, such that their plus ends interdigitate at the equator. Membrane vesicles are thought to move along the MTs toward the equator and fuse to form the cell plate. Although several genes required for phragmoplast MT organization have been identified, the mechanisms that maintain the bipolarity of phragmoplasts remain poorly understood. Here, we show that engaging phragmoplast MTs in a bipolar fashion in protonemal cells of the moss Physcomitrella patens requires the conserved MT cross-linking protein MICROTUBULE-ASSOCIATED PROTEIN65 (MAP65). Simultaneous knockdown of the three MAP65s expressed in those cells severely compromised MT interdigitation at the phragmoplast equator after anaphase onset, resulting in the collapse of the phragmoplast in telophase. Cytokinetic vesicles initially localized to the anaphase midzone as normal but failed to further accumulate in the next several minutes, although the bipolarity of the MT array was preserved. Our data indicate that the presence of bipolar MT arrays is insufficient for vesicle accumulation at the equator and further suggest that MAP65-mediated MT interdigitation is a prerequisite for maintenance of bipolarity of the phragmoplast and accumulation and/or fusion of cell plate-destined vesicles at the equatorial plane. PMID:24272487

  12. Petroleum occurrences and plate tectonics

    SciTech Connect

    Olenin, V.B.; Sokolov, B.A.

    1983-01-01

    This paper analyzes the mechanisms of petroleum formation and petroleum accumulation proposed in recent years by some Russian and foreign investigators from the viewpoint of the new global or plate tectonics. On the basis of discussion and the facts, the authors conclude that the mechanisms proposed are in contradiction to reality and their use in practical application is at least premature.

  13. Corrugated cover plate for flat plate collector

    DOEpatents

    Hollands, K. G. Terry; Sibbitt, Bruce

    1978-01-01

    A flat plate radiant energy collector is providing having a transparent cover. The cover has a V-corrugated shape which reduces the amount of energy reflected by the cover away from the flat plate absorber of the collector.

  14. Plate Tectonic Cycle. K-6 Science Curriculum.

    ERIC Educational Resources Information Center

    Blueford, J. R.; And Others

    Plate Tectonics Cycle is one of the units of a K-6 unified science curriculum program. The unit consists of four organizing sub-themes: (1) volcanoes (covering formation, distribution, and major volcanic groups); (2) earthquakes (with investigations on wave movements, seismograms and sub-suface earth currents); (3) plate tectonics (providing maps…

  15. Cross strip anode readouts for large format, photon counting microchannel plate detectors: developing flight qualified prototypes of the detector and electronics

    NASA Astrophysics Data System (ADS)

    Vallerga, John; Raffanti, Rick; Cooney, Michael; Cumming, Harley; Varner, Gary; Seljak, Andrej

    2014-07-01

    Photon counting microchannel plate (MCP) imagers have been the detector of choice for most UV astronomical missions over the last two decades (e.g. EUVE, FUSE, COS on Hubble etc.). Over this duration, improvements in the MCP laboratory readout technology have resulted in better spatial resolution (x10), temporal resolution (x1000) and output event rate (x100), all the while operating at lower gain (x 10) resulting in lower high voltage requirements and longer MCP lifetimes. One such technology is the parallel cross strip (PXS) readout. Laboratory versions of PXS electronics have demonstrated < 20 μm FWHM spatial resolution, count rates on the order of 2 MHz, and temporal resolution of ~ 1ns. In 2012 our group at U.C. Berkeley, along with our partners at the U. Hawaii, received a Strategic Astrophysics Technology grant to raise the TRL of the PXS detector and electronics from 4 to 6 by replacing most of the high powered electronics with application specific integrated circuits (ASICs) which will lower the power, mass and volume requirements of the PXS detector. We were also tasked to design and fabricate a "standard" 50mm square active area MCP detector incorporating these electronics that can be environmentally qualified for flight (temperature, vacuum, vibration). The first ASICs designed for this program have been fabricated and are undergoing testing. We present the latest progress on these ASIC designs and performance and show imaging results from the new 50 x 50 mm XS detector.

  16. Formation and evolution of a metasomatized lithospheric root at the motionless Antarctic plate: the case of East Island, Crozet Archipelago (Indian Ocean)

    NASA Astrophysics Data System (ADS)

    Meyzen, Christine; Marzoli, Andrea; Bellieni, Giuliano; Levresse, Gilles

    2016-04-01

    Sitting atop the nearly stagnant Antarctic plate (ca. 6.46 mm/yr), the Crozet archipelago midway between Madagascar and Antarctica constitutes a region of unusually shallow (1543-1756 m below sea level) and thickened oceanic crust (10-16.5 km), high geoid height, and deep low-velocity zone, which may reflect the surface expression of a mantle plume. Here, we present new major and trace element data for Quaternary sub-aerial alkali basalts from East Island, the easterly and oldest island (ca. 9 Ma) of the Crozet archipelago. Crystallization at uppermost mantle depth and phenocryst accumulation have strongly affected their parental magma compositions. Their trace element patterns show a large negative K anomaly relative to Ta-La, moderate depletions in Rb and Ba with respect to Th-U, and heavy rare earth element (HREE) depletions relative to light REE. These characteristics allow limits to be placed upon the composition and mineralogy of their mantle source. The average trace element spectrum of East Island basalts can be matched by melting of about 2 % of a garnet-phlogopite-bearing peridotite source. The stability field of phlogopite restricts melting depth to lithospheric levels. The modelled source composition requires a multistage evolution, where the mantle has been depleted by melt extraction before having been metasomatized by alkali-rich plume melts. The depleted mantle component may be sourced by residual mantle plume remnants stagnated at the melting locus due to a weak lateral flow velocity inside the melting regime, whose accumulation progressively edifies a depleted lithospheric root above the plume core. Low-degree alkali-rich melts are likely derived from the plume source. Such a mantle source evolution may be general to both terrestrial and extraterrestrial environments where the lateral component velocity of the mantle flow field is extremely slow.

  17. Plate-like osteoma cutis.

    PubMed

    Orme, Charisse M; Hale, Christopher S; Meehan, Shane A; Long, Wendy

    2014-12-16

    Osteoma cutis is the aberrant development of bone within the skin. The bone formation may be de novo (primary) or result from an injury to the skin (secondary). Here we present a healthy 53-year-old man with no known abnormalities in calcium or phosphate metabolism with plate-like osteoma cutis of the scalp. Plate- or plaque-like osteoma cutis was initially described as a congenital condition but has now been reported several times in the literature as an idiopathic process that occurs in adults. Treatment options are limited and are only required if the lesion is bothersome to the patient.

  18. Sputtering and ion plating

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The proceedings of a conference on sputtering and ion plating are presented. Subjects discussed are: (1) concepts and applications of ion plating, (2) sputtering for deposition of solid film lubricants, (3) commercial ion plating equipment, (4) industrial potential for ion plating and sputtering, and (5) fundamentals of RF and DC sputtering.

  19. Formation and retention of surface pores in helium-implanted nano-grain tungsten for fusion reactor first-wall materials and divertor plates

    NASA Astrophysics Data System (ADS)

    Zenobia, S. J.; Kulcinski, G. L.

    2009-12-01

    Nano-grain W samples were implanted with 30 keV 3He ions to fluences of 1021, 1022 and 1023 He m-2, at temperatures ranging from approximately 1273 to 1423 K. One specimen was implanted with 30 keV 4He ions at 1273 K to 1024 He m-2. Scanning electron microscopy showed the onset of visible surface pore formation occurred between approximately 1021 and 1022 He+ m-2 and increased with higher implant fluences, eventually resulting in a 'coral-like' surface structure. Focused ion beam analysis revealed the depth of visible subsurface pores increased with higher doses, extending below the surface to a maximum value of approximately 730 nm. Using 3He(d, p)4He nuclear reaction analysis on 3He+ implanted specimens retained helium fluences were found to range from 4.0×1020 to 4.5×1021 He m-2. Each specimen sustained mass loss after implantation which was observed to increase with greater He+ dose.

  20. The Postcranial Skeleton of an Exceptionally Complete Individual of the Plated Dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming, U.S.A.

    PubMed

    Maidment, Susannah Catherine Rose; Brassey, Charlotte; Barrett, Paul Michael

    2015-01-01

    Although Stegosaurus is one of the most iconic dinosaurs, well-preserved fossils are rare and as a consequence there is still much that remains unknown about the taxon. A new, exceptionally complete individual affords the opportunity to describe the anatomy of Stegosaurus in detail for the first time in over a century, and enables additional comparisons with other stegosaurian dinosaurs. The new specimen is from the Red Canyon Ranch Quarry, near Shell Wyoming, and appears to have been so well preserved because it was buried rapidly in a pond or body of standing water immediately after death. The quarry is probably located in the middle part of the Morrison Formation, which is believed to be Tithonian in age in this area. The specimen is referable to Stegosaurus stenops based on the possession of an edentulous anterior portion of the dentary and elevated postzygapophyses on the cervical vertebrae. New information provided by the specimen concerns the morphology of the vertebrae, the iliosacral block and dermal armor. Several aspects of its morphology indicate the individual was not fully skeletally mature at the time of death, corroborating a previous histological study.

  1. The Postcranial Skeleton of an Exceptionally Complete Individual of the Plated Dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming, U.S.A.

    PubMed Central

    Maidment, Susannah Catherine Rose; Brassey, Charlotte; Barrett, Paul Michael

    2015-01-01

    Although Stegosaurus is one of the most iconic dinosaurs, well-preserved fossils are rare and as a consequence there is still much that remains unknown about the taxon. A new, exceptionally complete individual affords the opportunity to describe the anatomy of Stegosaurus in detail for the first time in over a century, and enables additional comparisons with other stegosaurian dinosaurs. The new specimen is from the Red Canyon Ranch Quarry, near Shell Wyoming, and appears to have been so well preserved because it was buried rapidly in a pond or body of standing water immediately after death. The quarry is probably located in the middle part of the Morrison Formation, which is believed to be Tithonian in age in this area. The specimen is referable to Stegosaurus stenops based on the possession of an edentulous anterior portion of the dentary and elevated postzygapophyses on the cervical vertebrae. New information provided by the specimen concerns the morphology of the vertebrae, the iliosacral block and dermal armor. Several aspects of its morphology indicate the individual was not fully skeletally mature at the time of death, corroborating a previous histological study. PMID:26466098

  2. Earth's Decelerating Tectonic Plates

    SciTech Connect

    Forte, A M; Moucha, R; Rowley, D B; Quere, S; Mitrovica, J X; Simmons, N A; Grand, S P

    2008-08-22

    Space geodetic and oceanic magnetic anomaly constraints on tectonic plate motions are employed to determine a new global map of present-day rates of change of plate velocities. This map shows that Earth's largest plate, the Pacific, is presently decelerating along with several other plates in the Pacific and Indo-Atlantic hemispheres. These plate decelerations contribute to an overall, globally averaged slowdown in tectonic plate speeds. The map of plate decelerations provides new and unique constraints on the dynamics of time-dependent convection in Earth's mantle. We employ a recently developed convection model constrained by seismic, geodynamic and mineral physics data to show that time-dependent changes in mantle buoyancy forces can explain the deceleration of the major plates in the Pacific and Indo-Atlantic hemispheres.

  3. A sensitive and simple plaque formation method for the Stx2 phage of Escherichia coli O157:H7, which does not form plaques in the standard plating procedure.

    PubMed

    Islam, Md Rakibul; Ogura, Yoshitoshi; Asadulghani, Md; Ooka, Tadasuke; Murase, Kazunori; Gotoh, Yasuhiro; Hayashi, Tetsuya

    2012-05-01

    Bacteriophages are fascinating genetic elements that play key roles in the evolution and diversification of bacterial genomes. Shiga toxin (Stx)-transducing phages are important genetic elements that disseminate the stx genes among enterohemorrhagic Escherichia coli (EHEC). They are generally regarded as lambda-like phages, but their biological and genetic properties have not been fully elucidated. This is partly due to a serious obstacle in obtaining visible plaques. Here, we describe a modified double agar overlay method that allows us to easily detect and accurately enumerate plaques of Sp5, the Stx2 phage of the EHEC O157 Sakai strain, which otherwise does not produce plaques in the standard plating procedure. In the modified method, the top agar was supplemented with mitomycin C (MMC) and Ca(2+) (or Mg(2+)). MMC appears to prevent the lysogenization of Sp5 and/or compel Sp5 to follow the lytic cycle by inducing the SOS response in the host cells. The divalent cations significantly improve phage adsorption to the host cells and thus yield a synergistic effect in combination with MMC. We further applied this method to a receptor analysis of Sp5 and obtained findings that suggest that the YaeT (BamA) protein serves as the receptor of Sp5. This method would be a very useful tool in studies of Stx2 phages and studies of other phages from various bacteria, in which researchers often encounter problems with plaque formation.

  4. ASSEMBLY OF PARALLEL PLATES

    DOEpatents

    Groh, E.F.; Lennox, D.H.

    1963-04-23

    This invention is concerned with a rigid assembly of parallel plates in which keyways are stamped out along the edges of the plates and a self-retaining key is inserted into aligned keyways. Spacers having similar keyways are included between adjacent plates. The entire assembly is locked into a rigid structure by fastening only the outermost plates to the ends of the keys. (AEC)

  5. Accelerated plate tectonics.

    PubMed

    Anderson, D L

    1975-03-21

    The concept of a stressed elastic lithospheric plate riding on a viscous asthenosphere is used to calculate the recurrence interval of great earthquakes at convergent plate boundaries, the separation of decoupling and lithospheric earthquakes, and the migration pattern of large earthquakes along an arc. It is proposed that plate motions accelerate after great decoupling earthquakes and that most of the observed plate motions occur during short periods of time, separated by periods of relative quiescence.

  6. Rotatable shear plate interferometer

    DOEpatents

    Duffus, Richard C.

    1988-01-01

    A rotatable shear plate interferometer comprises a transparent shear plate mounted obliquely in a tubular supporting member at 45.degree. with respect to its horizontal center axis. This tubular supporting member is supported rotatably around its center axis and a collimated laser beam is made incident on the shear plate along this center axis such that defocus in different directions can be easily measured.

  7. Plating Tank Control Software

    1998-03-01

    The Plating Tank Control Software is a graphical user interface that controls and records plating process conditions for plating in high aspect ratio channels that require use of low current and long times. The software is written for a Pentium II PC with an 8 channel data acquisition card, and the necessary shunt resistors for measuring currents in the millampere range.

  8. An improved plating process

    NASA Technical Reports Server (NTRS)

    Askew, John C.

    1994-01-01

    An alternative to the immersion process for the electrodeposition of chromium from aqueous solutions on the inside diameter (ID) of long tubes is described. The Vessel Plating Process eliminates the need for deep processing tanks, large volumes of solutions, and associated safety and environmental concerns. Vessel Plating allows the process to be monitored and controlled by computer thus increasing reliability, flexibility and quality. Elimination of the trivalent chromium accumulation normally associated with ID plating is intrinsic to the Vessel Plating Process. The construction and operation of a prototype Vessel Plating Facility with emphasis on materials of construction, engineered and operational safety and a unique system for rinse water recovery are described.

  9. Angular shear plate

    SciTech Connect

    Ruda, Mitchell C.; Greynolds, Alan W.; Stuhlinger, Tilman W.

    2009-07-14

    One or more disc-shaped angular shear plates each include a region thereon having a thickness that varies with a nonlinear function. For the case of two such shear plates, they are positioned in a facing relationship and rotated relative to each other. Light passing through the variable thickness regions in the angular plates is refracted. By properly timing the relative rotation of the plates and by the use of an appropriate polynomial function for the thickness of the shear plate, light passing therethrough can be focused at variable positions.

  10. Plate Tectonics, Geographical Information System, paleogeography

    SciTech Connect

    Moore, Thomas L.; Scotese, Christopher

    2002-05-24

    The PaleoX.framwork is a dynamically linked/loaded framework for Cocoa applications. The primary goal of this library is to standardize several elements used for working with paleogeographic data. This includes objects designed to organize information for tectonic plates, including maps, rotation objects, plate names, and designations. In addition, PaleoX provides object-oriented solutions for handling standard paleogeographic file formats from the PALEOMAP Project.

  11. Plate-induced Miocene extension in southern California

    SciTech Connect

    Stuart, W.D. Univ. of California, Santa Barbara, CA )

    1992-01-01

    Miocene crustal extension in southern California can be explained by the interaction of tectonic plates in relative motion. The Pacific, Juan de Fuca, and Farallon (Guadalupe) plates are represented by flat elastic plates surrounded by an infinite elastic plate, the eastern part of which represents the North America plate. Forcing is by assigned subduction pull, and tractions at all plate boundaries satisfy a viscous constitutive law. Plate bottoms are stress-free. In the first part of the solution plate velocities and boundary tractions are found from static equilibrium. Then principal horizontal stresses and strains in plate interiors caused by tractions and subduction pull are found by a boundary element procedure. Using plate boundary geometry from Stock and Hodges for early- and mid-Miocene times, it is found that the portion of the North America plate margin between the Mendocino and Rivera triple junctions has maximum extensional strain directed westward. This result is generally consistent with directions associated with metamorphic core complex formation in southern California. The model is also consistent with extensional strain and rotation sense of crustal blocks in the vicinity of Los Angeles, as inferred by Luyendyk and others from paleomagnetic data. In the model the greatest extensional strain of the North America plate occurs near the Pacific-North America transform, in the area above the absent Farallon slab. Extension direction varies from northwest to southwest according to plate geometry, subduction pull (Juan de Fuca and Guadalupe), and plate boundary tractions.

  12. Multicolor printing plate joining

    NASA Technical Reports Server (NTRS)

    Waters, W. J. (Inventor)

    1984-01-01

    An upper plate having ink flow channels and a lower plate having a multicolored pattern are joined. The joining is accomplished without clogging any ink flow paths. A pattern having different colored parts and apertures is formed in a lower plate. Ink flow channels each having respective ink input ports are formed in an upper plate. The ink flow channels are coated with solder mask and the bottom of the upper plate is then coated with solder. The upper and lower plates are pressed together at from 2 to 5 psi and heated to a temperature of from 295 F to 750 F or enough to melt the solder. After the plates have cooled and the pressure is released, the solder mask is removed from the interior passageways by means of a liquid solvent.

  13. Geologically current plate motions

    NASA Astrophysics Data System (ADS)

    DeMets, Charles; Gordon, Richard G.; Argus, Donald F.

    2010-04-01

    We describe best-fitting angular velocities and MORVEL, a new closure-enforced set of angular velocities for the geologically current motions of 25 tectonic plates that collectively occupy 97 per cent of Earth's surface. Seafloor spreading rates and fault azimuths are used to determine the motions of 19 plates bordered by mid-ocean ridges, including all the major plates. Six smaller plates with little or no connection to the mid-ocean ridges are linked to MORVEL with GPS station velocities and azimuthal data. By design, almost no kinematic information is exchanged between the geologically determined and geodetically constrained subsets of the global circuit-MORVEL thus averages motion over geological intervals for all the major plates. Plate geometry changes relative to NUVEL-1A include the incorporation of Nubia, Lwandle and Somalia plates for the former Africa plate, Capricorn, Australia and Macquarie plates for the former Australia plate, and Sur and South America plates for the former South America plate. MORVEL also includes Amur, Philippine Sea, Sundaland and Yangtze plates, making it more useful than NUVEL-1A for studies of deformation in Asia and the western Pacific. Seafloor spreading rates are estimated over the past 0.78 Myr for intermediate and fast spreading centres and since 3.16 Ma for slow and ultraslow spreading centres. Rates are adjusted downward by 0.6-2.6mmyr-1 to compensate for the several kilometre width of magnetic reversal zones. Nearly all the NUVEL-1A angular velocities differ significantly from the MORVEL angular velocities. The many new data, revised plate geometries, and correction for outward displacement thus significantly modify our knowledge of geologically current plate motions. MORVEL indicates significantly slower 0.78-Myr-average motion across the Nazca-Antarctic and Nazca-Pacific boundaries than does NUVEL-1A, consistent with a progressive slowdown in the eastward component of Nazca plate motion since 3.16 Ma. It also

  14. Hypervelocity plate acceleration

    SciTech Connect

    Marsh, S.P.; Tan, T.H.

    1991-01-01

    Shock tubes have been used to accelerate 1.5-mm-thick stainless steel plates to high velocity while retaining their integrity. The fast shock tubes are 5.1-cm-diameter, 15.2-cm-long cylinders of PBX-9501 explosive containing a 1.1-cm-diameter cylindrical core of low-density polystyrene foam. The plates have been placed directly in contact with one face of the explosive system. Plane-wave detonation was initiated on the opposite face. A Mach disk was formed in the imploding styrofoam core, which provided the impulse required to accelerate the metal plate to high velocity. Parametric studies were made on this system to find the effect of varying plate metal, plate thickness, foam properties, and addition of a barrel. A maximum plate velocity of 9.0 km/s has been observed. 6 refs., 17 figs.

  15. Plating methods, a survey

    NASA Technical Reports Server (NTRS)

    Berkowitz, J. B.; Emerson, N. H.

    1972-01-01

    Results are presented of a comprehensive search of the literature available, much of which has been generated by the research centers of NASA and its contractors, on plating and coating methods and techniques. Methods covered included: (1) electroplating from aqueous solutions; (2) electroplating from nonaqueous solutions; (3) electroplating from fused-salt baths; (4) electroforming; (5) electroless plating, immersion plating, and mirroring; (6) electroplating from gaseous plasmas; and (7) anodized films and conversion coatings.

  16. GOLD PLATING PROCESS

    DOEpatents

    Seegmiller, R.

    1957-08-01

    An improved bath is reported for plating gold on other metals. The composition of the plating bath is as follows: Gold cyanide from about 15 to about 50 grams, potassium cyanide from about 70 to about 125 grams, and sulfonated castor oil from about 0.1 to about 10 cc. The gold plate produced from this bath is smooth, semi-hard, and nonporous.

  17. PLATES WITH OXIDE INSERTS

    DOEpatents

    West, J.M.; Schumar, J.F.

    1958-06-10

    Planar-type fuel assemblies for nuclear reactors are described, particularly those comprising fuel in the oxide form such as thoria and urania. The fuel assembly consists of a plurality of parallel spaced fuel plate mennbers having their longitudinal side edges attached to two parallel supporting side plates, thereby providing coolant flow channels between the opposite faces of adjacent fuel plates. The fuel plates are comprised of a plurality of longitudinally extending tubular sections connected by web portions, the tubular sections being filled with a plurality of pellets of the fuel material and the pellets being thermally bonded to the inside of the tubular section by lead.

  18. Tectonic Evolution of the Jurassic Pacific Plate

    NASA Astrophysics Data System (ADS)

    Nakanishi, M.; Ishihara, T.

    2015-12-01

    We present the tectonic evolution of the Jurassic Pacific plate based on magnetic anomly lineations and abyssal hills. The Pacific plate is the largest oceanic plate on Earth. It was born as a microplate aroud the Izanagi-Farallon-Phoenix triple junction about 192 Ma, Early Jurassic [Nakanishi et al., 1992]. The size of the Pacific plate at 190 Ma was nearly half that of the present Easter or Juan Fernandez microplates in the East Pacific Rise [Martinez et at, 1991; Larson et al., 1992]. The plate boundary surrounding the Pacific plate from Early Jurassic to Early Cretaceous involved the four triple junctions among Pacific, Izanagi, Farallon, and Phoenix plates. The major tectonic events as the formation of oceanic plateaus and microplates during the period occurred in the vicinity of the triple junctions [e.g., Nakanishi and Winterer, 1998; Nakanishi et al., 1999], implying that the study of the triple junctions is indispensable for understanding the tectonic evolution of the Pacific plate. Previous studies indicate instability of the configuration of the triple junctions from Late Jurassic to Early Cretaceous (155-125 Ma). On the other hand, the age of the birth of the Pacific plate was determined assuming that all triple junctions had kept their configurations for about 30 m.y. [Nakanishi et al., 1992] because of insufficient information of the tectonic history of the Pacific plate before Late Jurassic.Increase in the bathymetric and geomagnetic data over the past two decades enables us to reveal the tectonic evolution of the Pacific-Izanagi-Farallon triple junction before Late Jurassic. Our detailed identication of magnetic anomaly lineations exposes magnetic bights before anomaly M25. We found the curved abyssal hills originated near the triple junction, which trend is parallel to magnetic anomaly lineations. These results imply that the configuration of the Pacific-Izanagi-Farallon triple junction had been RRR before Late Jurassic.

  19. Performance evaluation of the R6R018 fuel plate using PLATE code

    SciTech Connect

    Pavel G. Medvedev; Hakan Ozaltun

    2010-03-01

    The paper presents results of performance evaluation of the R6R018 fuel plate using PLATE code. R6R018 is a U-7Mo dispersion type mini-plate with Al-3.5Si matrix irradiated in the RERTR-9B experiment. The design of this plate is prototypical of the planned LEONIDAS irradiation test. Therefore, a detailed performance analysis of this plate is important to confirm acceptable behavior in pile, and to provide baseline and justification for further analysis and testing. Specific results presented in the paper include fuel temperature history, growth of the interaction layer between the U-Mo and the matrix, swelling, growth of the corrosion layer, and degradation of thermal conductivity. The methodology of the analysis will be discussed including the newly developed capability to account for the formation of the interaction layer during fuel fabrication.

  20. Earthquakes and plate tectonics

    USGS Publications Warehouse

    Spall, H.

    1977-01-01

    An explanation is to be found in plate tectonics, a concept which has revolutionized thinking in the Earth sciences in the last 10 years. The theory of plate tectonics combines many of the ideas about continental drift (originally proposed in 1912 by Alfred Wegener in Germany) and sea-floor spreading (suggested originally by Harry Hess of Princeton University). 

  1. Blue Willow Story Plates

    ERIC Educational Resources Information Center

    Fontes, Kris

    2009-01-01

    In the December 1997 issue of "SchoolArts" is a lesson titled "Blue Willow Story Plates" by Susan Striker. In this article, the author shares how she used this lesson with her middle-school students many times over the years. Here, she describes a Blue Willow plate painting project that her students made.

  2. Turbine vane plate assembly

    SciTech Connect

    Schiavo Jr., Anthony L.

    2006-01-10

    A turbine vane assembly includes a turbine vane having first and second shrouds with an elongated airfoil extending between. Each end of the airfoil transitions into a shroud at a respective junction. Each of the shrouds has a plurality of cooling passages, and the airfoil has a plurality of cooling passages extending between the first and second shrouds. A substantially flat inner plate and an outer plate are coupled to each of the first and second shrouds so as to form inner and outer plenums. Each inner plenum is defined between at least the junction and the substantially flat inner plate; each outer plenum is defined between at least the substantially flat inner plate and the outer plate. Each inner plenum is in fluid communication with a respective outer plenum through at least one of the cooling passages in the respective shroud.

  3. Plating To Reinforce Welded Joints

    NASA Technical Reports Server (NTRS)

    Otousa, J. E.

    1982-01-01

    Electrodeposition used to strengthen welded joints gouged, nicked, or suffered other mechanical damage. Plating cell, typically of acrylic plastic such as poly (Methylmetacrylate), is assembled around part to be plated. Areas not to be plated are masked with plater's tape. Weld area is plated in standard nickel-plating process.

  4. Syncytial-Type Cell Plates

    PubMed Central

    Otegui, Marisa; Staehelin, L. Andrew

    2000-01-01

    Cell wall formation in the syncytial endosperm of Arabidopsis was studied by using high-pressure-frozen/freeze-substituted developing seeds and immunocytochemical techniques. The endosperm cellularization process begins at the late globular embryo stage with the synchronous organization of small clusters of oppositely oriented microtubules (∼10 microtubules in each set) into phragmoplast-like structures termed mini-phragmoplasts between both sister and nonsister nuclei. These mini-phragmoplasts produce a novel kind of cell plate, the syncytial-type cell plate, from Golgi-derived vesicles ∼63 nm in diameter, which fuse by way of hourglass-shaped intermediates into wide (∼45 nm in diameter) tubules. These wide tubules quickly become coated and surrounded by a ribosome-excluding matrix; as they grow, they branch and fuse with each other to form wide tubular networks. The mini-phragmoplasts formed between a given pair of nuclei produce aligned tubular networks that grow centrifugally until they merge into a coherent wide tubular network with the mini-phragmoplasts positioned along the network margins. The individual wide tubular networks expand laterally until they meet and eventually fuse with each other at the sites of the future cell corners. Transformation of the wide tubular networks into noncoated, thin (∼27 nm in diameter) tubular networks begins at multiple sites and coincides with the appearance of clathrin-coated budding structures. After fusion with the syncytial cell wall, the thin tubular networks are converted into fenestrated sheets and cell walls. Immunolabeling experiments show that the cell plates and cell walls of the endosperm differ from those of the embryo and maternal tissue in two features: their xyloglucans lack terminal fucose residues on the side chain, and callose persists in the cell walls after the cell plates fuse with the parental plasma membrane. The lack of terminal fucose residues on xyloglucans suggests that these cell wall

  5. Earthquakes and plate tectonics.

    USGS Publications Warehouse

    Spall, H.

    1982-01-01

    Earthquakes occur at the following three kinds of plate boundary: ocean ridges where the plates are pulled apart, margins where the plates scrape past one another, and margins where one plate is thrust under the other. Thus, we can predict the general regions on the earth's surface where we can expect large earthquakes in the future. We know that each year about 140 earthquakes of magnitude 6 or greater will occur within this area which is 10% of the earth's surface. But on a worldwide basis we cannot say with much accuracy when these events will occur. The reason is that the processes in plate tectonics have been going on for millions of years. Averaged over this interval, plate motions amount to several mm per year. But at any instant in geologic time, for example the year 1982, we do not know, exactly where we are in the worldwide cycle of strain build-up and strain release. Only by monitoring the stress and strain in small areas, for instance, the San Andreas fault, in great detail can we hope to predict when renewed activity in that part of the plate tectonics arena is likely to take place. -from Author

  6. Lohse's historic plate archive

    NASA Astrophysics Data System (ADS)

    Tsvetkov, M.; Tsvetkova, K.; Richter, G.; Scholz, G.; Böhm, P.

    The description and the analysis of Oswald Lohse's astrophotographic plates, collected at the Astrophysical Observatory Potsdam in the period 1879 - 1889, are presented. 67 plates of the archive, taken with the greatest instrument of the observatory at that time - the refractor (D = 0.30 m, F = 5.40 m, scale = 38''/mm) and with the second heliographic objective (D = 0.13 m, F = 1.36 m, scale = 152''/mm) - - survived two world wars in relative good condition. The plate emulsions are from different manufacturers in the beginning of astrophotography (Gädicke, Schleussner, Beernaert, etc.). The sizes of the plates are usually 9x12 cm2, which corresponds to fields of 1.2deg and 5deg respectively for each instrument mentioned above. The average limiting magnitude is 13.0(pg). Besides of the plates received for technical experiments (work on photographic processes, testing of new instruments and methods of observations), the scientific observations follow programs for studies of planet surfaces, bright stars, some double stars, stellar clusters and nebulous objects. Lohse's archive is included into the Wide Field Plate Database (http://www.skyarchive.org) as the oldest systematic one, covering the fields of Orion (M42/43), Pleiades, h & chi Persei, M37, M3, M11, M13, M92, M31, etc. With the PDS 2020 GM+ microdensitometer of Münster University 10 archive plates were digitized.

  7. Computational valve plate design

    NASA Astrophysics Data System (ADS)

    Kalbfleisch, Paul

    Axial piston machines are widely used in many industries for their designs compactness, flexibility in power transfer, variable flow rate, and high efficiencies as compared to their manufacturing costs. One important component of all axial piston machines that is a very influential on the performance of the unit is the valve plate. The aim of this research is to develop a design methodology that is general enough to design all types of valve plates and the simple enough not to require advanced technical knowledge from the user. A new style of valve plate designs has been developed that comprehensively considers all previous design techniques and does not require significant changes to the manufacturing processes of valve plates. The design methodology utilizes a previously developed accurate computer model of the physical phenomenon. This allows the precise optimization of the valve plate design through the use of simulations rather than expensive trial and error processes. The design of the valve plate is clarified into the form of an optimization problem. This formulation into an optimization problem has motivated the selection of an optimization algorithm that satisfies the requirements of the design. The proposed design methodology was successfully tested in a case study in the shown to be very successful in improving required performance of the valve plate design.

  8. Plate removal following orthognathic surgery.

    PubMed

    Little, Mhairi; Langford, Richard Julian; Bhanji, Adam; Farr, David

    2015-11-01

    The objectives of this study are to determine the removal rates of orthognathic plates used during orthognathic surgery at James Cook University Hospital and describe the reasons for plate removal. 202 consecutive orthognathic cases were identified between July 2004 and July 2012. Demographics and procedure details were collected for these patients. Patients from this group who returned to theatre for plate removal between July 2004 and November 2012 were identified and their notes were analysed for data including reason for plate removal, age, smoking status, sex and time to plate removal. 3.2% of plates were removed with proportionally more plates removed from the mandible than the maxilla. 10.4% of patients required removal of one or more plate. Most plates were removed within the first post-operative year. The commonest reasons for plate removal were plate exposure and infection. The plate removal rates in our study are comparable to those seen in the literature.

  9. Silver plating ensures reliable diffusion bonding of dissimilar metals

    NASA Technical Reports Server (NTRS)

    1967-01-01

    Dissimilar metals are reliably joined by diffusion bonding when the surfaces are electroplated with silver. The process involves cleaning and etching, anodization, silver striking, and silver plating with a conventional plating bath. It minimizes the formation of detrimental intermetallic phases and provides greater tolerance of processing parameters.

  10. Plate tectonics, habitability and life

    NASA Astrophysics Data System (ADS)

    Spohn, Tilman; Breuer, Doris

    2016-04-01

    The role of plate tectonics in defining habitability of terrestrial planets is being increasingly discussed (e.g., Elkins-Tanton, 2015). Plate tectonics is a significantly evolved concept with a large variety of aspects. In the present context, cycling of material between near surface and mantle reservoirs is most important. But increased heat transport through mixing of cold lithosphere with the deep interior and formation of continental crust may also matter. An alternative mechanism of material cycling between these reservoirs is hot-spot volcanism combined with crust delamination. Hot-spot volcanism will transport volatiles to the atmosphere while delamination will mix crust, possibly altered by sedimentation and chemical reactions, with the mantle. The mechanism works as long as the stagnant lithosphere plate has not grown thicker than the crust and as long as volcanic material is added onto the crust. Thermal evolution studies suggest that the mechanism could work for the first 1-2 Ga of planetary evolution. The efficiency of the mechanism is limited by the ratio of extrusive to intrusive volcanism, which is thought to be less than 0.25. Plate tectonics would certainly have an advantage by working even for more evolved planets. A simple, most-used concept of habitability requires the thermodynamic stability of liquid water on the surface of a planet. Cycling of CO2between the atmosphere, oceans and interior through subduction and surface volcanism is an important element of the carbonate-silicate cycle, a thermostat feedback cycle that will keep the atmosphere from entering into a runaway greenhouse. Calculations for a model Earth lacking plate tectonics but degassing CO2, N, and H2O to form a surface ocean and a secondary atmosphere (Tosi et al, 2016) suggest that liquid water can be maintained on the surface for 4.5Ga. The model planet would then qualify as habitable. It is conceivable that the CO2 buffering capability of its ocean together with silicate

  11. Reduction of astrometric plates

    NASA Technical Reports Server (NTRS)

    Stock, J.

    1984-01-01

    A rapid and accurate method for the reduction of comet or asteroid plates is described. Projection equations, scale length correction, rotation of coordinates, linearization, the search for additional reference stars, and the final solution are examined.

  12. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors. PMID:25618046

  13. Violin plate modes.

    PubMed

    Gough, Colin

    2015-01-01

    As the first step toward developing a generic model for the acoustically radiating vibrational modes of the violin and related instruments, the modes of both freely supported and edge-constrained top and back plates have been investigated as functions of shape, arching height, elastic anisotropy, the f-holes and associated island area, thickness graduations, and the additional boundary constraints of the ribs, soundpost, and bass-bar present in the assembled instrument. Comsol shell structure finite element software has been used as a quasi-experimental tool, with physical and geometric properties varied smoothly, often over several orders of magnitude, allowing the development of the plate modes to be followed continuously from those of an initially square plate to those of doubly-arched, guitar-shaped, orthotropic plates and their dependence on all the above factors.

  14. Flat plate solar oven

    SciTech Connect

    Parikh, M.

    1981-01-01

    The construction of an Indian Rs. 186 (US $20.33) flat-plate solar oven is described. Detailed drawings are provided and relevant information on cooking times and temperature for different foods is given.

  15. Tectonic Plate Movement.

    ERIC Educational Resources Information Center

    Landalf, Helen

    1998-01-01

    Presents an activity that employs movement to enable students to understand concepts related to plate tectonics. Argues that movement brings topics to life in a concrete way and helps children retain knowledge. (DDR)

  16. Plate tectonics: Metamorphic myth

    NASA Astrophysics Data System (ADS)

    Korenaga, Jun

    2016-01-01

    Clear evidence for subduction-induced metamorphism, and thus the operation of plate tectonics on the ancient Earth has been lacking. Theoretical calculations indicate that we may have been looking for something that cannot exist.

  17. Positive battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John R. (Inventor)

    1985-01-01

    The power characteristics of a lead acid battery are improved by incorporating a dispersion of 1 to 10% by weight of a thermodynamically stable conductivity additive, such as conductive tin oxide coated glass fibers (34) of filamentary glass wool (42) in the positive active layer (32) carried on the grid (30) of the positive plate (16). Positive plate potential must be kept high enough to prevent reduction of the tin oxide to tin by utilizing an oversized, precharged positive paste.

  18. Fractal multifiber microchannel plates

    NASA Technical Reports Server (NTRS)

    Cook, Lee M.; Feller, W. B.; Kenter, Almus T.; Chappell, Jon H.

    1992-01-01

    The construction and performance of microchannel plates (MCPs) made using fractal tiling mehtods are reviewed. MCPs with 40 mm active areas having near-perfect channel ordering were produced. These plates demonstrated electrical performance characteristics equivalent to conventionally constructed MCPs. These apparently are the first MCPs which have a sufficiently high degree of order to permit single channel addressability. Potential applications for these devices and the prospects for further development are discussed.

  19. Carbon-fibre reinforced plates for problem fractures.

    PubMed

    Pemberton, D J; McKibbin, B; Savage, R; Tayton, K; Stuart, D

    1992-01-01

    We report our experience with carbon-fibre reinforced plastic (CFRP) plates in the management of 19 problem fractures complicated by either infection, nonunion, comminution or contamination. The combination offers secure fixation without inhibition of callus formation.

  20. The Potsdam Plate Archive

    NASA Astrophysics Data System (ADS)

    Boehm, P.; Steinmetz, M.; Tsvetkov, M.; Tsvetkova, K.

    2006-08-01

    The Virtual Observatory (VO) project will provide a global network platform to support modern astronomical research with fast and easy access to distributed archives via a unified interface and data model. Our aim is to include the historical photographic plates of the Potsdam observatory into this database in the framework of GAVO, the German contribution to VO. This work is part of the DFG project 436 BUL. The Postdam collection of wide-field plates consists of 11 archives, obtained from 1879 to 1970 (see Catalogue of Wide-Field Plate Archives, version 5.0, March 2005, http://www.skyarchive.org/catalogue.html), with a total amount of about 10000 plates and films stored not only in Potsdam but also in Leiden and Sonneberg. Apart from the long timeline provided for the observed objects, the archives reflect the history and development of the Potsdam observatory and of astronomical photography as well. The first astronomical photographs represent a scientific treasure. They offer the possibility to follow the photometric behavior of astronomical objects for about 120 years. This information is unique, because no more reproducible. Our aim is to digitize the old plates as long as their physical status does still allow it, and continue their systematic incorporation into the already existing Wide-Field Plate Database. These data can be used to search for any kind of long-term brightness variations like new flare stars or rapidly varying stars (Froehlich et al., 2002, A&A 391).

  1. Relationship between plume and plate tectonics

    NASA Astrophysics Data System (ADS)

    Puchkov, V. N.

    2016-07-01

    The relationship between plate- and plume-tectonics is considered in view of the growth and breakdown of supercontinents, active rifting, the formation of passive volcanic-type continental margins, and the origin of time-progressive volcanic chains on oceanic and continental plates. The mantle wind phenomenon is described, as well as its effect on plume morphology and anisotropy of the ambient mantle. The interaction of plumes and mid-ocean ridges is discussed. The principles and problems of plume activity analysis in subduction- and collision-related foldbelts are considered and illustrated with examples.

  2. Caribbean plate interactions

    SciTech Connect

    Ball, M. )

    1993-02-01

    Vector analysis of plate motions, derived from studies of Atlantic magnetic lineations and fracture zone trends, indicates the following relative movements between the Caribbean, North American, and South American Plates. (1) During Early Jurassic to Early Cretaceous, the North American Plate moved 1900 km westward and 900 km northward relative to the South American Plate. A broad zone including the Caribbean region, i.e., the zone between the North and South America Plates, was a site of left-lateral shear and north-south extension. (2) During Early Cretaceous to Late Cretaceous, the North American Mate moved an additional 1200 km westward relative to South America across this zone. (3) During Late Cretaceous to the end of the Eocene, the North American Plate moved 200 km westward and 400 km northward relative to the South American Plate. (4) From the end of the Eocene to near the end of the Miocene, North America converged on South America some 200 km and moved 100 km eastward relative to it. Through the Mesozoic and earliest Tertiary history of the Caribbean, the region was a shear zone within which left-lateral displacement exceeded 3000 km and north-south extension exceeded 1300 km. In regard to time, 80% of the history of the Caribbean region is one of north-south extension and left-lateral shear. In terms of space, 97% of the shear is left-lateral and the ratio of divergence versus convergence is 7 to 1. Thus, characterizing the Caribbean region, and the Atlantic to its east, as a zone of north-south extension and left-lateral shear, is a fair generalization.

  3. Cadmium plating replacements

    NASA Technical Reports Server (NTRS)

    Nelson, Mary J.; Groshart, Earl C.

    1995-01-01

    The Boeing Company has been searching for replacements to cadmium plate. Two alloy plating systems seem close to meeting the needs of a cadmium replacement. The two alloys, zinc-nickel and tin-zinc are from alloy plating baths; both baths are neutral pH. The alloys meet the requirements for salt fog corrosion resistance, and both alloys excel as a paint base. Currently, tests are being performed on standard fasteners to compare zinc-nickel and tin-zinc on threaded hardware where cadmium is heavily used. The Hydrogen embrittlement propensity of the zinc-nickel bath has been tested, and just beginning for the tin-zinc bath. Another area of interest is the electrical properties on aluminum for tin-zinc and will be discussed. The zinc-nickel alloy plating bath is in production in Boeing Commercial Airplane Group for non-critical low strength steels. The outlook is promising that these two coatings will help The Boeing Company significantly reduce its dependence on cadmium plating.

  4. When Did Plate Tectonics Begin

    NASA Astrophysics Data System (ADS)

    Brown, M.

    2015-12-01

    Present-day plate tectonics on Earth is characterized by asymmetric (one-sided) subduction, but how do we recognize the imprint of subduction in the geologic record? How do we weigh global (commonly younger) vs local (commonly older) datasets or distinguish initiation from episodic from continuous subduction? How reliable are data gaps? Characteristics of the Paleozoic record of subduction include calc-alkaline magmatism, blueschist/UHP metamorphism and collisional orogenesis, and ophiolites as representatives of former ocean lithosphere. Are these characteristic rocks preserved in Proterozoic, Archean and Hadean crust? Does a hotter mantle, higher heat production and weaker lithosphere modify or eliminate these features? What preceded subduction and how do we recognize that regime? Are rock associations or geochemical fingerprints reliable? Does reworking and overprinting modify geochemical fingerprints? Proposals for the start of plate tectonics have been based on: persistence of isotope anomalies/fractionated chemical domains in the mantle; changes in chemistry of magmatic rocks, rates of crustal growth vs reworking, and sites of growth; the metamorphic record, particularly the first appearance of contrasting thermal gradients or eclogite (including evidence from mineral inclusions in diamonds) or UHP metamorphic rocks; stabilization of cratonic lithosphere and formation of supercratons, and the beginning of the Proterozoic supercontinent cycle; the end of the flat Earth, emergence of continents, development of significant topography, changes in the style of orogeny and the rise in atmospheric oxygen; and, the appearance of passive margins and changes in the style of sedimentation. Estimates of the timing have varied from the Hadean to Neoproterozoic. I will summarize evidence for a growing consensus that the late Mesoarchean to early Paleoproterozoic was a 700 Myr long period of transition to continuous (?) subduction and global (?) mobile-lid plate tectonics.

  5. Optimization of device geometry in single-plate digital microfluidics

    NASA Astrophysics Data System (ADS)

    Abdelgawad, Mohamed; Park, Philip; Wheeler, Aaron R.

    2009-05-01

    Digital microfluidics is a popular tool for lab-on-a-chip applications and is typically implemented in one of two formats: single-plate ("open") devices or two-plate ("closed") devices. Single-plate devices have some advantages relative to the more common two-plate format such as faster mixing, the capacity to move larger volumes on a given footprint, and easier access to droplets for handling or optical detection. In contrast with the two-plate format, in which ground potential is generally supplied via a top electrode, in the single-plate format, many different geometries of ground wires/electrodes have been used. Until the present study, there has been no metric to determine which of these geometries is best suited for droplet actuation. Here, we present a combination of numerical simulations and experimental tests to compare six different single-plate designs. We applied finite element analysis, using the commercially available COMSOL software package to calculate the electrodynamic actuation forces in each of the different designs and used the results to optimize device design. Forces predicted by the electrodynamic model were in agreement with forces predicted using electromechanical models. More importantly, results were verified experimentally using a unique technique that permits indirect estimation of actuation forces on digital microfluidic devices. This work illustrates the promise of using numerical modeling to enhance the design and performance of digital microfluidic devices.

  6. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1987-01-01

    A liquid-impermeable plate (10) having through-plate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with led spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  7. Plate-mantle coupling from post-Pangea plate kinematics

    NASA Astrophysics Data System (ADS)

    Zahirovic, Sabin; Dietmar Müller, R.; Seton, Maria; Flament, Nicolas

    2015-04-01

    Convection in the Earth's mantle that involves plates at the surfaces gives rise to plate velocities that vary through time and depend on the balance of plate boundary forces, with the present-day providing a snapshot of this ongoing process. However, present-day plate velocities do not capture plate behaviour over geologically representative timeframes and thus cannot be used to evaluate factors limiting plate velocities. Previous studies investigated the effects of continental keels on plate speeds by either using the present-day snapshot or a limited number of reconstructed plate configurations, often leading to conflicting results. For example, an early assumption was that continental keels (especially cratons) were unlikely to impede fast plate motions because India's velocity approached ~20 cm/yr in the Eocene prior to the collision with Eurasia. We employ a modern plate reconstruction approach with evolving global topological plate boundaries for the post-Pangea timeframe (since 200 Ma) to evaluate factors controlling plate velocities. Plate boundary configurations and plate velocities are extracted from the open-source and cross-platform plate reconstruction package GPlates (www.gplates.org) at 1 Myr intervals. For each plate, at each timestep, the area of continental and cratonic lithosphere is calculated to evaluate the effect on plate velocities. Our results support that oceanic plates tend to be 2-3 times faster than plates with large portion of continental plate area, consistent with predictions of numerical models of mantle convection. The fastest plates (~8.5 cm/yr RMS) are dominated by oceanic plate area and high subducting portion of plate perimeter, while the slowest plates (~2.6-2.8 cm/yr RMS) are dominated by continental plate area and bounded by transforms and mid-oceanic ridge segments. Importantly, increasing cratonic fractions (both Proterozoic and Archean lithosphere) significantly impede plate velocities, suggesting that deep continental

  8. NICKEL PLATING PROCESS

    DOEpatents

    Hoover, T.B.; Zava, T.E.

    1959-05-12

    A simplified process is presented for plating nickel by the vapor decomposition of nickel carbonyl. In a preferred form of the invention a solid surface is nickel plated by subjecting the surface to contact with a mixture containing by volume approximately 20% nickel carbonyl vapor, 2% hydrogen sulfide and .l% water vapor or 1% oxygen and the remainder carbon dioxide at room temperature until the desired thickness of nickel is obtained. The advantage of this composition over others is that the normally explosive nickel carbonyl is greatly stabilized.

  9. Reduced Plating Ignitron

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt A (Inventor); Pearson, J Boise (Inventor)

    2014-01-01

    An ignitron apparatus has an airtight tubular housing having a first sealed end and a second sealed end. An anode is connected at the first sealed end, projecting into the housing, and a recess at the second sealed and forms a well which contains a quantity of liquid gallium or gallium alloy making up the cathode. An ignitor projects through the liquid metal and into the housing. The inner surface of the housing includes at least one plating-reduction structure to prevent electrical shorting of the apparatus caused by plating of the liquid metal.

  10. Elastocapillary coalescence of plates and pillars

    PubMed Central

    Wei, Z.; Schneider, T. M.; Kim, J.; Kim, H.-Y.; Aizenberg, J.; Mahadevan, L.

    2015-01-01

    When a fluid-immersed array of supported plates or pillars is dried, evaporation leads to the formation of menisci on the tips of the plates or pillars that bring them together to form complex patterns. Building on prior experimental observations, we use a combination of theory and computation to understand the nature of this instability and its evolution in both the two- and three-dimensional setting of the problem. For the case of plates, we explicitly derive the interaction torques based on the relevant physical parameters associated with pillar deformation, contact-line pinning/depinning and fluid volume changes. A Bloch-wave analysis for our periodic mechanical system captures the window of volumes where the two-plate eigenvalue characterizes the onset of the coalescence instability. We then study the evolution of these binary clusters and their eventual elastic arrest using numerical simulations that account for evaporative dynamics coupled to capillary coalescence. This explains both the formation of hierarchical clusters and the sensitive dependence of the final structures on initial perturbations, as seen in our experiments. We then generalize our analysis to treat the problem of pillar collapse in three dimensions, where the fluid domain is completely connected and the interface is a minimal surface with the uniform mean curvature. Our theory and simulations capture the salient features of experimental observations in a range of different situations and may thus be useful in controlling the ensuing patterns. PMID:25792949

  11. Interaction of Vortex Ring with Cutting Plate

    NASA Astrophysics Data System (ADS)

    Musta, Mustafa

    2015-11-01

    The interaction of a vortex ring impinging on a thin cutting plate was made experimentally using Volumetric 3-component Velocitmetry (v3v) technique. The vortex rings were generated with piston-cylinder vortex ring generator using piston stroke-to-diameter ratios and Re at 2-3 and 1500 - 3000, respectively. The cutting of vortex rings below center line leads to the formation of secondary vortices on each side of the plate which is look like two vortex rings, and a third vortex ring propagates further downstream in the direction of the initial vortex ring, which is previously showed by flow visualization study of Weigand (1993) and called ``trifurcation''. Trifurcation is very sensitive to the initial Reynolds number and the position of the plate with respect to the vortex ring generator pipe. The present work seeks more detailed investigation on the trifurcation using V3V technique. Conditions for the formation of trifurcation is analyzed and compared with Weigand (1993). The formed secondary vortex rings and the propagation of initial vortex ring in the downstream of the plate are analyzed by calculating their circulation, energy and trajectories.

  12. Nuclear reactor alignment plate configuration

    DOEpatents

    Altman, David A; Forsyth, David R; Smith, Richard E; Singleton, Norman R

    2014-01-28

    An alignment plate that is attached to a core barrel of a pressurized water reactor and fits within slots within a top plate of a lower core shroud and upper core plate to maintain lateral alignment of the reactor internals. The alignment plate is connected to the core barrel through two vertically-spaced dowel pins that extend from the outside surface of the core barrel through a reinforcement pad and into corresponding holes in the alignment plate. Additionally, threaded fasteners are inserted around the perimeter of the reinforcement pad and into the alignment plate to further secure the alignment plate to the core barrel. A fillet weld also is deposited around the perimeter of the reinforcement pad. To accomodate thermal growth between the alignment plate and the core barrel, a gap is left above, below and at both sides of one of the dowel pins in the alignment plate holes through with the dowel pins pass.

  13. Unitary plate electrode

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor); Clough, Thomas J. (Inventor); Josefowicz, Jack Y. (Inventor); Sibert, John W. (Inventor)

    1985-01-01

    The unitary electrode (10) comprises a porous sheet (12) of fiberglass the strands (14) of which contain a coating (16) of conductive tin oxide. The lower portion of the sheet contains a layer (18) of resin and the upper layer (20) contains lead dioxide forming a positive active electrode on an electrolyte-impervious layer. The strands (14) form a continuous conduction path through both layers (16, 18). Tin oxide is prevented from reduction by coating the surface of the plate facing the negative electrode with a conductive, impervious layer resistant to reduction such as a thin film (130) of lead or graphite filled resin adhered to the plate with a layer (31) of conductive adhesive. The plate (10) can be formed by casting a molten resin from kettle (60) onto a sheet of glass wool (56) overlying a sheet of lead foil and then applying positive active paste from hopper (64) into the upper layer (68). The plate can also be formed by passing an assembly of a sheet ( 80) of resin, a sheet (86) of sintered glass and a sheet (90) of lead between the nip (92) of heated rollers (93, 95) and then filling lead oxide into the pores (116) of the upper layer (118).

  14. The Plate Tectonics Project

    ERIC Educational Resources Information Center

    Hein, Annamae J.

    2011-01-01

    The Plate Tectonics Project is a multiday, inquiry-based unit that facilitates students as self-motivated learners. Reliable Web sites are offered to assist with lessons, and a summative rubric is used to facilitate the holistic nature of the project. After each topic (parts of the Earth, continental drift, etc.) is covered, the students will…

  15. INL HIP Plate Fabrication

    SciTech Connect

    B. H. Park; C. R. Clark; J. F. Jue

    2010-02-01

    This document outlines the process used to bond monolithic fuel plates by Hot Isostatic Pressing (HIP). This method was developed at Idaho National Laboratory (INL) for the Reduced Enrichment for Research and Test Reactors (RERTR) program. These foils have been used in a number of irradiation experiments in support of the United States Global Threat Reduction Initiative (GTRI) program.

  16. Growth Plate Injuries

    MedlinePlus

    ... or crushed, the growth plate may close prematurely, forming a bony bridge or “bar.” The risk of ... this publication: James S. Panagis, M.D., M.P.H., NIAMS/NIH; R. Tracy Ballock, M.D., Case ...

  17. Geology and plate-tectonic development

    SciTech Connect

    Irwin, W.P.

    1990-01-01

    The San Andreas fault is a transform fault along the boundary between the Pacific and North American plates. Bedrock along the fault includes various lithologic units that range in age from Precambrian to Tertiary and younger. Some bedrock units that can be matched across the fault suggest strike-slip displacement of as much as 560 km. This chapter describes geologic formations of northern and central California, including Franciscan rocks, Coast Range ophiolite, Great Valley sequence, Coast Range thrust, Salinian block, displacement of pre-Quaternary rocks by the San Andreas fault, and the relation of geologic structure to seismic behavior. Formations of southern California which are described are the Transverse Ranges and the Salton Trough and displacement of basement rocks by the San Andreas fault. Plate-tectonic development of the San Andreas fault is also discussed.

  18. MyPlate Food Guide

    MedlinePlus

    ... follow throughout your life. 2. Fruits Like veggies, fruits contain vitamins, minerals, and fiber. The red section of MyPlate is slightly smaller than the green, but together fruits and veggies should fill half your plate. Whole ...

  19. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are:  Child abuse  Injury from extreme cold (for example, frostbite)  Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  20. What Are Growth Plate Injuries?

    MedlinePlus

    ... activities. Other reasons for growth plate injuries are: Child abuse Injury from extreme cold (for example, frostbite) Radiation ( ... problems) treats most growth plate injuries. At other times, the child will see a pediatric orthopaedic surgeon (a doctor ...

  1. North American plate dynamics

    NASA Technical Reports Server (NTRS)

    Richardson, Randall M.; Reding, Lynn M.

    1991-01-01

    Deformation within the North American plate in response to various tectonic processes is modeled using an elastic finite element analysis. The tectonic processes considered in the modeling include ridge forces associated with the normal thermal evolution of oceanic lithosphere, shear and normal stresses transmitted across transforms, normal stresses transmitted across convergent boundaries, stresses due to horizontal density contrasts within the continent, and shear tractions applied along the base of the plate. Model stresses are calculated with respect to a lithostatic reference stress state. Shear stresses transmitted across transform boundaries along the San Andreas and Caribbean are small, of the order of 5-10 MPa. Also, compressive stresses of the order of 5-10 MPa transmitted across the major transforms improve the fit to the data. Compressive stresses across convergent margins along the Aleutians and the Middle America trench are important.

  2. Microchannel plate streak camera

    DOEpatents

    Wang, Ching L.

    1989-01-01

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 KeV x-rays.

  3. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1984-09-28

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras. The improved streak camera is far more sensitive to photons (uv to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1000 keV x-rays.

  4. Microchannel plate streak camera

    DOEpatents

    Wang, C.L.

    1989-03-21

    An improved streak camera in which a microchannel plate electron multiplier is used in place of or in combination with the photocathode used in prior streak cameras is disclosed. The improved streak camera is far more sensitive to photons (UV to gamma-rays) than the conventional x-ray streak camera which uses a photocathode. The improved streak camera offers gamma-ray detection with high temporal resolution. It also offers low-energy x-ray detection without attenuation inside the cathode. Using the microchannel plate in the improved camera has resulted in a time resolution of about 150 ps, and has provided a sensitivity sufficient for 1,000 KeV x-rays. 3 figs.

  5. Bipolar battery plate

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1985-01-01

    A liquid-impermeable plate (10) having throughplate conductivity with essentially zero resistance comprises an insulator sheet (12) having a series of spaced perforations (14) each of which contains a metal element (16) sealingly received into the perforation (14). A low-cost plate can readily be manufactured by punching a thermoplastic sheet (40) such as polypropylene with a punching tool (52), filling the apertures with lead spheres (63) having a diameter smaller than the holes (50) but larger than the thickness of the sheet, sweeping excess spheres (62) off the sheet with a doctor blade (60) and then pressing a heated platen (74) onto the sheet to swage the spheres into a cylindrical shape and melt the surrounding resin to form a liquid-impermeable collar (4) sealing the metal into the sheet.

  6. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Reynolds, L.; Tweed, H.

    1972-01-01

    The work performed entailed the design, development, construction and testing of a 4000 word by 18 bit random access, NDRO plated wire memory for use in conjunction with a spacecraft imput/output unit and central processing unit. The primary design parameters, in order of importance, were high reliability, low power, volume and weight. A single memory unit, referred to as a qualification model, was delivered.

  7. Plate motion and deformation

    SciTech Connect

    Minster, B.; Prescott, W.; Royden, L.

    1991-02-01

    Our goal is to understand the motions of the plates, the deformation along their boundaries and within their interiors, and the processes that control these tectonic phenomena. In the broadest terms, we must strive to understand the relationships of regional and local deformation to flow in the upper mantle and the rheological, thermal and density structure of the lithosphere. The essential data sets which we require to reach our goal consist of maps of current strain rates at the earth's surface and the distribution of integrated deformation through time as recorded in the geologic record. Our success will depend on the effective synthesis of crustal kinematics with a variety of other geological and geophysical data, within a quantitative theoretical framework describing processes in the earth's interior. Only in this way can we relate the snapshot of current motions and earth structure provided by geodetic and geophysical data with long-term processes operating on the time scales relevant to most geological processes. The wide-spread use of space-based techniques, coupled with traditional geological and geophysical data, promises a revolution in our understanding of the kinematics and dynamics of plate motions over a broad range of spatial and temporal scales and in a variety of geologic settings. The space-based techniques that best address problems in plate motion and deformation are precise space-geodetic positioning -- on land and on the seafloor -- and satellite acquisition of detailed altimetric and remote sensing data in oceanic and continental areas. The overall science objectives for the NASA Solid Earth Science plan for the 1990's, are to Understand the motion and deformation of the lithosphere within and across plate boundaries'', and to understand the dynamics of the mantle, the structure and evolution of the lithosphere, and the landforms that result from local and regional deformation. 57 refs., 7 figs., 2 tabs.

  8. Martian plate tectonics

    NASA Astrophysics Data System (ADS)

    Sleep, N. H.

    1994-03-01

    The northern lowlands of Mars have been produced by plate tectonics. Preexisting old thick highland crust was subducted, while seafloor spreading produced thin lowland crust during late Noachian and Early Hesperian time. In the preferred reconstruction, a breakup margin extended north of Cimmeria Terra between Daedalia Planum and Isidis Planitia where the highland-lowland transition is relatively simple. South dipping subduction occured beneath Arabia Terra and east dipping subduction beneath Tharsis Montes and Tempe Terra. Lineations associated with Gordii Dorsum are attributed to ridge-parallel structures, while Phelegra Montes and Scandia Colles are interpreted as transfer-parallel structures or ridge-fault-fault triple junction tracks. Other than for these few features, there is little topographic roughness in the lowlands. Seafloor spreading, if it occurred, must have been relatively rapid. Quantitative estimates of spreading rate are obtained by considering the physics of seafloor spreading in the lower (approx. 0.4 g) gravity of Mars, the absence of vertical scarps from age differences across fracture zones, and the smooth axial topography. Crustal thickness at a given potential temperature in the mantle source region scales inversely with gravity. Thus, the velocity of the rough-smooth transition for axial topography also scales inversely with gravity. Plate reorganizations where young crust becomes difficult to subduct are another constraint on spreading age. Plate tectonics, if it occurred, dominated the thermal and stress history of the planet. A geochemical implication is that the lower gravity of Mars allows deeper hydrothermal circulation through cracks and hence more hydration of oceanic crust so that more water is easily subducted than on the Earth. Age and structural relationships from photogeology as well as median wavelength gravity anomalies across the now dead breakup and subduction margins are the data most likely to test and modify hypotheses

  9. Plates with Incompatible Prestrain

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Kaushik; Lewicka, Marta; Schäffner, Mathias

    2016-07-01

    We study effective elastic behavior of the incompatibly prestrained thin plates, where the prestrain is independent of thickness and uniform through the plate's thickness h. We model such plates as three-dimensional elastic bodies with a prescribed pointwise stress-free state characterized by a Riemannian metric G, and seek the limiting behavior as {h to 0}. We first establish that when the energy per volume scales as the second power of h, the resulting {Γ} -limit is a Kirchhoff-type bending theory. We then show the somewhat surprising result that there exist non-immersible metrics G for whom the infimum energy (per volume) scales smaller than h 2. This implies that the minimizing sequence of deformations carries nontrivial residual three-dimensional energy but it has zero bending energy as seen from the limit Kirchhoff theory perspective. Another implication is that other asymptotic scenarios are valid in appropriate smaller scaling regimes of energy. We characterize the metrics G with the above property, showing that the zero bending energy in the Kirchhoff limit occurs if and only if the Riemann curvatures R 1213, R 1223 and R 1212 of G vanish identically. We illustrate our findings with examples; of particular interest is an example where {G_{2 × 2}}, the two-dimensional restriction of G, is flat but the plate still exhibits the energy scaling of the Föppl-von Kármán type. Finally, we apply these results to a model of nematic glass, including a characterization of the condition when the metric is immersible, for {G = Id3 + γ n ⊗ n} given in terms of the inhomogeneous unit director field distribution { n in R^3}.

  10. On the strain energy of laminated composite plates

    NASA Technical Reports Server (NTRS)

    Atilgan, Ali R.; Hodges, Dewey H.

    1991-01-01

    The present effort to obtain the asymptotically correct form of the strain energy in inhomogeneous laminated composite plates proceeds from the geometrically nonlinear elastic theory-based three-dimensional strain energy by decomposing the nonlinear three-dimensional problem into a linear, through-the-thickness analysis and a nonlinear, two-dimensional analysis analyzing plate formation. Attention is given to the case in which each lamina exhibits material symmetry about its middle surface, deriving closed-form analytical expressions for the plate elastic constants and the displacement and strain distributions through the plate's thickness. Despite the simplicity of the plate strain energy's form, there are no restrictions on the magnitudes of displacement and rotation measures.

  11. Symmetries in laminated composite plates

    NASA Technical Reports Server (NTRS)

    Noor, A. K.

    1976-01-01

    The different types of symmetry exhibited by laminated anisotropic fibrous composite plates are identified and contrasted with the symmetries of isotropic and homogeneous orthotropic plates. The effects of variations in the fiber orientation and the stacking sequence of the layers on the symmetries exhibited by composite plates are discussed. Both the linear and geometrically nonlinear responses of the plates are considered. A simple procedure is presented for exploiting the symmetries in the finite element analysis. Examples are given of square, skew and polygonal plates where use of symmetry concepts can significantly reduce the scope and cost of analysis.

  12. Iberian plate kinematics: A jumping plate boundary between Eurasia and Africa

    USGS Publications Warehouse

    Srivastava, S.P.; Schouten, Hans; Roest, W.R.; Klitgord, Kim D.; Kovacs, L.C.; Verhoef, J.; Macnab, R.

    1990-01-01

    THE rotation of Iberia and its relation to the formation of the Pyrenees has been difficult to decipher because of the lack of detailed sea-floor spreading data, although several models have been proposed1-7. Here we use detailed aeromagnetic measurements from the sea floor offshore of the Grand Banks of Newfoundland to show that Iberia moved as part of the African plate from late Cretaceous to mid-Eocene time, with a plate boundary extending westward from the Bay of Biscay. When motion along this boundary ceased, a boundary linking extension in the King's Trough to compression along the Pyrenees came into existence. Finally, since the late Oligocene, Iberia has been part of the Eurasian plate, with the boundary between Eurasia and Africa situated along the Azores-Gibraltar fracture zone.

  13. Hypervelocity impact on shielded plates

    NASA Technical Reports Server (NTRS)

    Smith, James P.

    1993-01-01

    A ballistic limit equation for hypervelocity impact on thin plates is derived analytically. This equation applies to cases of impulsive impact on a plate that is protected by a multi-shock shield, and it is valid in the range of velocity above 6 km/s. Experimental tests were conducted at the NASA Johnson Space Center on square aluminum plates. Comparing the center deflections of these plates with the theoretical deflections of a rigid-plastic plate subjected to a blast load, one determines the dynamic yield strength of the plate material. The analysis is based on a theory for the expansion of the fragmented projectile and on a simple failure criterion. Curves are presented for the critical projectile radius versus the projectile velocity, and for the critical plate thickness versus the velocity. These curves are in good agreement with curves that have been generated empirically.

  14. Fuel cell end plate structure

    DOEpatents

    Guthrie, Robin J.; Katz, Murray; Schroll, Craig R.

    1991-04-23

    The end plates (16) of a fuel cell stack (12) are formed of a thin membrane. Pressure plates (20) exert compressive load through insulation layers (22, 26) to the membrane. Electrical contact between the end plates (16) and electrodes (50, 58) is maintained without deleterious making and breaking of electrical contacts during thermal transients. The thin end plate (16) under compressive load will not distort with a temperature difference across its thickness. Pressure plate (20) experiences a low thermal transient because it is insulated from the cell. The impact on the end plate of any slight deflection created in the pressure plate by temperature difference is minimized by the resilient pressure pad, in the form of insulation, therebetween.

  15. Self-Sustained Oscillations in Flows around Long Blunt Plates

    NASA Astrophysics Data System (ADS)

    Hourigan, K.; Thompson, M. C.; Tan, B. T.

    2001-04-01

    The presence of flow separation from both leading and trailing edges of elongated bluff bodies leads to vortex interactions and resonances not observed in shorter bodies such as circular and square cylinders. Stepwise behaviour in the Strouhal number with increasing plate chord-to-thickness ratio has been observed for long bodies in a number of different situations: natural shedding, under transverse forcing, and with excited duct modes. In the present study, an investigation is made of the predicted unforced laminar flow around long plates (up to chord, c, to thickness, t, ratio c/t=16). The two main types of plate geometry considered are rectangular plates and plates with an aerodynamic leading edge. The rectangular plate represents a geometrical extension of the normal flat and square plates. The aerodynamic leading-edge plate is a natural precursor to the rectangular plate because the vortex shedding is only from the trailing edge. The natural flow around rectangular plates is of greater complexity due to the interaction between the leading- and trailing-edge shedding. The previously neglected influence of the trailing-edge vortex shedding is found to play an important role in the stepwise progression of the Strouhal number with chord-to-thickness ratio. In addition, the formation of three-dimensional patterns in the boundary layer along the plate and in the trailing-edge wake is predicted. The predicted boundary layer hairpin vortices are compared with previous observations and the predicted streamwise modes in the wake are compared with those found in the case of circular cylinders.

  16. Plated wire memory subsystem

    NASA Technical Reports Server (NTRS)

    Carpenter, K. H.

    1974-01-01

    The design, construction, and test history of a 4096 word by 18 bit random access NDRO Plated Wire Memory for use in conjunction with a spacecraft input/output and central processing unit is reported. A technical and functional description is given along with diagrams illustrating layout and systems operation. Test data is shown on the procedures and results of system level and memory stack testing, and hybrid circuit screening. A comparison of the most significant physical and performance characteristics of the memory unit versus the specified requirements is also included.

  17. Shuttle plate braiding machine

    NASA Technical Reports Server (NTRS)

    Huey, Jr., Cecil O. (Inventor)

    1994-01-01

    A method and apparatus for moving yarn in a selected pattern to form a braided article. The apparatus includes a segmented grid of stationary support elements and a plurality of shuttles configured to carry yarn. The shuttles are supported for movement on the grid assembly and each shuttle includes a retractable plunger for engaging a reciprocating shuttle plate that moves below the grid assembly. Such engagement at selected times causes the shuttles to move about the grid assembly in a selected pattern to form a braided article of a particular geometry.

  18. Reduced hydrogen cadmium plating

    SciTech Connect

    Hoeller, T.; Ross, L. ); Varma, R. ); Agarwala, V.S. )

    1991-01-01

    This paper demonstrates the advantages of using a periodic reverse pulse plating method, incorporating a fast cathodic pulse which is separated from the subsequent anodic/cathodic pulses by a long rest period in producing silvery cadmium coatings on steel from aqueous fluoroborate electrolyte. Also, the deposition obtained by combination of pulse currents and turbulent electrolyte flow system (forced convection of electrolyte, Re {approximately} 20-25,000) result in a near hydrogen-free electrodeposition of fine- grained cadmium. This is confirmed by the determination of diffusible hydrogen by the electrochemical (Barnach Electrode) method.

  19. Survey of ion plating sources. [conferences

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1979-01-01

    Based on the type of evaporation source, gaseous media and mode of transport, the following is discussed: resistance, electron beam, sputtering, reactive and ion beam evaporation. Ionization efficiencies and ion energies in the glow discharge determine the percentage of atoms which are ionized under typical ion plating conditions. The plating flux consists of a small number of energetic ions and a large number of energetic neutrals. The energy distribution ranges from thermal energies up to a maximum energy of the discharge. The various reaction mechanisms which contribute to the exceptionally strong adherence - formation of a graded sustrate/coating interface are not fully understood, however the controlling factors are evaluated. The influence of process variables on the nucleation and growth characteristics are illustrated in terms of morphological changes which affect the mechanical and tribological properties of the coating.

  20. Plating on difficult-to-plate metals: what's new

    SciTech Connect

    Wiesner, H.J.

    1980-07-30

    Some of the changes since 1970 in procedures for plating on such materials as titanium, molybdenum, silicon, aluminum, and gallium arsenide are summarized. While basic procedures for plating some of these materials were developed as many as 30 to 40 years ago, changes in the end uses of the plated products have necessitated new plating processes. In some cases, vacuum techniques - such as ion bombardment, ion implantation, and vacuum metallization - have been introduced to improve the adhesion of electrodeposits. In other cases, these techniques have been used to deposit materials upon which electrodeposits are required.

  1. Localised Plate Motion on Venus

    NASA Astrophysics Data System (ADS)

    Ghail, R. C.

    1996-03-01

    The volcanic and tectonic features observed in Dali Vinculum, Parga Vinculum and Imdr Regio are concentrated at long, narrow, curvilinear zones, with relatively minor volcanism and tectonism between these zones. These zones, whilst more diffuse than terrestrial plate boundaries, nevertheless define the margins of tectonic plates. In contrast to Earth, however, it appears that venusian plates are neither created nor destroyed by lateral motion. Rather, plates are thinned and intruded at vincula plate boundaries, vertically accreted by small-scale intra-plate (planitia) volcanism and perhaps destroyed by delamination of thickened crust in tesserae and montane regions such as Thetis Regio and Ishtar Terra. The diversity in age both between and within these three areas together with the evidence for infrequent, small scale resurfacing in the planitiae are difficult to reconcile with a non-uniformitarian geological process.

  2. History and Evolution of Precambrian plate tectonics

    NASA Astrophysics Data System (ADS)

    Fischer, Ria; Gerya, Taras

    2014-05-01

    Plate tectonics is a global self-organising process driven by negative buoyancy at thermal boundary layers. Phanerozoic plate tectonics with its typical subduction and orogeny is relatively well understood and can be traced back in the geological records of the continents. Interpretations of geological, petrological and geochemical observations from Proterozoic and Archean orogenic belts however (e.g., Brown, 2006), suggest a different tectonic regime in the Precambrian. Due to higher radioactive heat production the Precambrian lithosphere shows lower internal strength and is strongly weakened by percolating melts. The fundamental difference between Precambrian and Phanerozoic tectonics is therefore the upper-mantle temperature, which determines the strength of the upper mantle (Brun, 2002) and the further tectonic history. 3D petrological-thermomechanical numerical modelling experiments of oceanic subduction at an active plate at different upper-mantle temperatures show these different subduction regimes. For upper-mantle temperatures < 175 K above the present day value a subduction style appears which is close to present day subduction but with more frequent slab break-off. At upper-mantle temperatures 175 - 250 K above present day values steep subduction continues but the plates are weakened enough to allow buckling and also lithospheric delamination and drip-offs. For upper-mantle temperatures > 250 K above the present day value no subduction occurs any more. The whole lithosphere is delaminating and due to strong volcanism and formation of a thicker crust subduction is inhibited. This stage of 200-250 K higher upper mantle temperature which corresponds roughly to the early Archean (Abbott, 1994) is marked by strong volcanism due to sublithospheric decompression melting which leads to an equal thickness for both oceanic and continental plates. As a consequence subduction is inhibited, but a compressional setup instead will lead to orogeny between a continental

  3. Channel plate for DNA sequencing

    DOEpatents

    Douthart, R.J.; Crowell, S.L.

    1998-01-13

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface. 15 figs.

  4. Ion plating for the future

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1981-01-01

    The ion plating techniques are classified relative to the instrumental set up, evaporation media, and mode of transport. A distinction is drawn between the low vacuum (plasma) and high vacuum (ion beam) techniques. Ion plating technology is discussed at the fundamental and industrial level. At the fundamental level, the capabilities and limitations of the plasma (evaporant flux) and film characteristics are evaluated. And on the industrial level, the performance and potential uses of ion plated films are discussed.

  5. Multiple plate hydrostatic viscous damper

    NASA Technical Reports Server (NTRS)

    Ludwig, L. P. (Inventor)

    1981-01-01

    A device for damping radial motion of a rotating shaft is described. The damper comprises a series of spaced plates extending in a radial direction. A hydraulic piston is utilized to place a load in these plates. Each annular plate is provided with a suitable hydrostatic bearing geometry on at least one of its faces. This structure provides a high degree of dampening in a rotor case system of turbomachinery in general. The damper is particularly useful in gas turbine engines.

  6. Plate heat exchanger design theory

    NASA Astrophysics Data System (ADS)

    Shah, R. K.; Wanniarachchi, A. S.

    Plate heat exchangers are commonly used in hygienic applications as well as in chemical processing and other industrial applications. Pertinent information on plate exchangers from a designer's point of view is summarized to provide a basic insight into performance behavior of chevron plates. Basic design methods are presented and a method of coupling between heat transfer and pressure drop is introduced. A step by step design procedure for rating and sizing problems is outlined.

  7. Channel plate for DNA sequencing

    DOEpatents

    Douthart, Richard J.; Crowell, Shannon L.

    1998-01-01

    This invention is a channel plate that facilitates data compaction in DNA sequencing. The channel plate has a length, a width and a thickness, and further has a plurality of channels that are parallel. Each channel has a depth partially through the thickness of the channel plate. Additionally an interface edge permits electrical communication across an interface through a buffer to a deposition membrane surface.

  8. Glass-bead peen plating

    NASA Technical Reports Server (NTRS)

    Graves, J. R.

    1974-01-01

    Peen plating of aluminum, copper, and nickel powders was investigated. Only aluminum was plated successfully within the range of peen plating conditions studied. Optimum plating conditions for aluminum were found to be: (1) bead/powder mixture containing 25 to 35% powder by weight, (2) peening intensity of 0.007A as measured by Almen strip, and (3) glass impact bead diameter of at least 297 microns (0.0117 inches) for depositing-100 mesh aluminum powder. No extensive cleaning or substrate preparation is required beyond removing loose dirt or heavy oil.

  9. True Shear Parallel Plate Viscometer

    NASA Technical Reports Server (NTRS)

    Ethridge, Edwin; Kaukler, William

    2010-01-01

    This viscometer (which can also be used as a rheometer) is designed for use with liquids over a large temperature range. The device consists of horizontally disposed, similarly sized, parallel plates with a precisely known gap. The lower plate is driven laterally with a motor to apply shear to the liquid in the gap. The upper plate is freely suspended from a double-arm pendulum with a sufficiently long radius to reduce height variations during the swing to negligible levels. A sensitive load cell measures the shear force applied by the liquid to the upper plate. Viscosity is measured by taking the ratio of shear stress to shear rate.

  10. Carbon-assisted flyer plates

    DOEpatents

    Stahl, David B.; Paisley, Dennis L.

    1994-01-01

    A laser driven flyer plate utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited.

  11. Intermittent plate tectonics?

    PubMed

    Silver, Paul G; Behn, Mark D

    2008-01-01

    Although it is commonly assumed that subduction has operated continuously on Earth without interruption, subduction zones are routinely terminated by ocean closure and supercontinent assembly. Under certain circumstances, this could lead to a dramatic loss of subduction, globally. Closure of a Pacific-type basin, for example, would eliminate most subduction, unless this loss were compensated for by comparable subduction initiation elsewhere. Given the evidence for Pacific-type closure in Earth's past, the absence of a direct mechanism for termination/initiation compensation, and recent data supporting a minimum in subduction flux in the Mesoproterozoic, we hypothesize that dramatic reductions or temporary cessations of subduction have occurred in Earth's history. Such deviations in the continuity of plate tectonics have important consequences for Earth's thermal and continental evolution.

  12. Downgoing plate controls on overriding plate deformation in subduction zones

    NASA Astrophysics Data System (ADS)

    Garel, Fanny; Davies, Rhodri; Goes, Saskia; Davies, Huw; Kramer, Stephan; Wilson, Cian

    2014-05-01

    Although subduction zones are convergent margins, deformation in the upper plate can be extensional or compressional and tends to change through time, sometimes in repeated episodes of strong deformation, e.g, phases of back-arc extension. It is not well understood what factors control this upper plate deformation. We use the code Fluidity, which uses an adaptive mesh and a free-surface formulation, to model a two-plate subduction system in 2-D. The model includes a composite temperature- and stress-dependent rheology, and plates are decoupled by a weak layer, which allows for free trench motion. We investigate the evolution of the state of stress and topography of the overriding plate during the different phases of the subduction process: onset of subduction, free-fall sinking in the upper mantle and interaction of the slab with the transition zone, here represented by a viscosity contrast between upper and lower mantle. We focus on (i) how overriding plate deformation varies with subducting plate age; (ii) how spontaneous and episodic back-arc spreading develops for some subduction settings; (iii) the correlation between overriding plate deformation and slab interaction with the transition zone; (iv) whether these trends resemble observations on Earth.

  13. 10. DETAIL OF BUILDER'S PLATE AT NORTH PORTAL. PLATE READS: ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. DETAIL OF BUILDER'S PLATE AT NORTH PORTAL. PLATE READS: 1889, BUILT BY THE BERLIN IRON BRIDGE CO. EAST BERLIN CONN. DOUGLAS & JARVIS PAT. APT. 16, 1878, AP'L 17, 1885. A.P. FORESMAN, WM. S. STARR, T.J. STREBEIGH, COMMISSIONERS. - Pine Creek Bridge, River Road spanning Pine Creek, Jersey Shore, Lycoming County, PA

  14. Plate motion controls on back-arc spreading. [Cenozoic movement in Western Pacific

    NASA Technical Reports Server (NTRS)

    Fein, J. B.; Jurdy, D. M.

    1986-01-01

    The motions of the subducting and the overriding plates influence the spatial and temporal distribution of back-arc spreading. Cenozoic plate motions in hot spot-fixed and no-net-rotation reference frames were studied with attention to correlations between changes in motion and episodes of back-arc spreading in the western Pacific. The results suggest that major back-arc opening occurs when both the overriding plate retreats from the trench in an absolute sense and the subducting plate undergoes a significant speed-up. Neither phenomenon alone is sufficient to initiate spreading. Three major plate velocity increases can be identified in the Cenozoic: (1) the Pacific plate 5-9 Ma; (2) the Indian plate at 27 Ma; and (3) the Pacific plate at 43 Ma, due to its shift from northerly to more westerly motion. At the present time, the Indian and Philippine are the only overriding plates that are retreating from their Pacific trenches and back-arc spreading occurs only on these two retreating plates. Although the Indian plate has been retreating for at least 25 Ma, back-arc spreading began only following the Pacific plate speed-up 5-9 Ma. Earlier, during the Indian plate speed-up, no overriding plates were retreating strongly and no back-arc spreading epsiodes are preserved from this time. For the earliest Pacific plate shift at 43 Ma, the Eurasian plate was not advancing, thus creating the only favorable plate kinematic conditions in the Cenozoic for back-arc basin formation in this region. It is unclear whether extension in the Japan Sea is a result of these conditions.

  15. Plate tectonics conserves angular momentum

    NASA Astrophysics Data System (ADS)

    Bowin, C.

    2010-03-01

    A new combined understanding of plate tectonics, Earth internal structure, and the role of impulse in deformation of the Earth's crust is presented. Plate accelerations and decelerations have been revealed by iterative filtering of the quaternion history for the Euler poles that define absolute plate motion history for the past 68 million years, and provide an unprecedented precision for plate angular rotation variations with time at 2-million year intervals. Stage poles represent the angular rotation of a plate's motion between adjacent Euler poles, and from which the maximum velocity vector for a plate can be determined. The consistent maximum velocity variations, in turn, yield consistent estimates of plate accelerations and decelerations. The fact that the Pacific plate was shown to accelerate and decelerate, implied that conservation of plate tectonic angular momentum must be globally conserved, and that is confirmed by the results shown here (total angular momentum ~1.4+27 kg m2 s-1). Accordingly, if a plate decelerates, other plates must increase their angular momentums to compensate. In addition, the azimuth of the maximum velocity vectors yields clues as to why the "bend" in the Emperor-Hawaiian seamount trend occurred near 46 Myr. This report summarizes processing results for 12 of the 14 major tectonic plates of the Earth (except for the Juan de Fuca and Philippine plates). Plate accelerations support the contention that plate tectonics is a product of torques that most likely are sustained by the sinking of positive density anomalies revealed by geoid anomalies of the degree 4-10 packet of the Earth's spherical harmonic coefficients. These linear positive geoid anomalies underlie plate subduction zones and are presumed due to phase changes in subducted gabbroic lithosphere at depth in the upper lower mantle (above 1200 km depth). The tectonic plates are pulled along by the sinking of these positive mass anomalies, rather than moving at near constant

  16. Plate tectonics, damage and inheritance

    NASA Astrophysics Data System (ADS)

    Bercovici, David; Ricard, Yanick

    2014-04-01

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  17. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates. PMID:24717430

  18. Plate tectonics, damage and inheritance.

    PubMed

    Bercovici, David; Ricard, Yanick

    2014-04-24

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto-subduction (about 4 billion years ago) and global tectonics (approximately 3 billion years ago) suggests that plates and plate boundaries became widespread over a period of 1 billion years. The reason for this time lag is unknown but fundamental to understanding the origin of plate tectonics. Here we suggest that when sufficient lithospheric damage (which promotes shear localization and long-lived weak zones) combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of weak plate boundaries and eventually to fully formed tectonic plates driven by subduction alone. We simulate this process using a grain evolution and damage mechanism with a composite rheology (which is compatible with field and laboratory observations of polycrystalline rocks), coupled to an idealized model of pressure-driven lithospheric flow in which a low-pressure zone is equivalent to the suction of convective downwellings. In the simplest case, for Earth-like conditions, a few successive rotations of the driving pressure field yield relic damaged weak zones that are inherited by the lithospheric flow to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even though flow is driven only by subduction. But for hotter surface conditions, such as those on Venus, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which corresponds to observations. After plates have developed, continued changes in driving forces, combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor plates.

  19. Effect of increased shear stress along a plate boundary fault on the formation of an out-of-sequence thrust and a break in surface slope within an accretionary wedge, based on numerical simulations

    NASA Astrophysics Data System (ADS)

    Miyakawa, Ayumu; Yamada, Yasuhiro; Matsuoka, Toshifumi

    2010-03-01

    We investigated the effect on accretionary wedge structure of increased shear stress, which describes the frictional sliding resistance along a decollement arising from an increase in material friction or reduction in pore pressure. To clarify the nature of the effect, we performed numerical simulations using two models: a Stable Friction model and an Increased Friction model. The Stable Friction model produced a low-angle, smooth, surface slope and an in-sequence thrust, whereas the Increased Friction model produced a break in surface slope (scarp) and an out-of-sequence thrust (OST) that cuts through the thrust sheet. The OST formed via the connection of segments of two adjacent thrusts, and its formation resulted in a change in the thickening mode of the wedge from thrust-sheet rotation and back-thrust activity to underplating. This contrast in thickening mode between the landward high-friction zone and seaward low-friction zone resulted in the formation of a clear break in slope, as the landward zone is steeper than the seaward zone, consistent with critical taper theory. The subduction of a basement slice or seamount can produce similar structures arising from an increase in resistance to basal shear sliding. However the distinctive structures arising in an accretionary wedge as a result of increased shear sliding resistance include a flat basal plane and absence of slope-failure sediments beneath the OST. These structural features are observed in accretionary wedges of the Nankai Trough off Muroto (Japan), the Sunda Strait, and the Barbados Ridge.

  20. Micro-channel plate detector

    SciTech Connect

    Elam, Jeffrey W.; Lee, Seon W.; Wang, Hsien -Hau; Pellin, Michael J.; Byrum, Karen; Frisch, Henry J.

    2015-09-22

    A method and system for providing a micro-channel plate detector. An anodized aluminum oxide membrane is provided and includes a plurality of nanopores which have an Al coating and a thin layer of an emissive oxide material responsive to incident radiation, thereby providing a plurality of radiation sensitive channels for the micro-channel plate detector.

  1. Metal vapor arc ion plating

    SciTech Connect

    Bertram, L.A.; Fisher, R.W.; Mattox, D.M.; Zanner, F.J.

    1986-09-09

    A method and apparatus for ion plating are described. The apparatus uses more negative than a first electrode voltage in a vacuum arc remelt system to attract low energy ions from the anode electrode to the article to be plated. 2 figs.

  2. Flat-plate heat pipe

    NASA Technical Reports Server (NTRS)

    Marcus, B. D.; Fleischman, G. L. (Inventor)

    1977-01-01

    Flat plate (vapor chamber) heat pipes were made by enclosing metal wicking between two capillary grooved flat panels. These heat pipes provide a unique configuration and have good capacity and conductance capabilities in zero gravity. When these flat plate vapor chamber heat pipes are heated or cooled, the surfaces are essentially isothermal, varying only 3 to 5 C over the panel surface.

  3. Metals plated on fluorocarbon polymers

    NASA Technical Reports Server (NTRS)

    Ford, H.; Krasinsky, J. B.; Vango, S. P.

    1964-01-01

    Electroplating lead on fluorocarbon polymer parts is accomplished by etching the parts to be plated with sodium, followed by successive depositions of silver and lead from ultrasonically agitated plating solutions. Metals other than lead may be electroplated on the silvered parts.

  4. Aseptic laboratory techniques: plating methods.

    PubMed

    Sanders, Erin R

    2012-05-11

    Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: Perform plating procedures without contaminating media. Isolate single bacterial colonies by the streak-plating

  5. Aseptic Laboratory Techniques: Plating Methods

    PubMed Central

    Sanders, Erin R.

    2012-01-01

    Microorganisms are present on all inanimate surfaces creating ubiquitous sources of possible contamination in the laboratory. Experimental success relies on the ability of a scientist to sterilize work surfaces and equipment as well as prevent contact of sterile instruments and solutions with non-sterile surfaces. Here we present the steps for several plating methods routinely used in the laboratory to isolate, propagate, or enumerate microorganisms such as bacteria and phage. All five methods incorporate aseptic technique, or procedures that maintain the sterility of experimental materials. Procedures described include (1) streak-plating bacterial cultures to isolate single colonies, (2) pour-plating and (3) spread-plating to enumerate viable bacterial colonies, (4) soft agar overlays to isolate phage and enumerate plaques, and (5) replica-plating to transfer cells from one plate to another in an identical spatial pattern. These procedures can be performed at the laboratory bench, provided they involve non-pathogenic strains of microorganisms (Biosafety Level 1, BSL-1). If working with BSL-2 organisms, then these manipulations must take place in a biosafety cabinet. Consult the most current edition of the Biosafety in Microbiological and Biomedical Laboratories (BMBL) as well as Material Safety Data Sheets (MSDS) for Infectious Substances to determine the biohazard classification as well as the safety precautions and containment facilities required for the microorganism in question. Bacterial strains and phage stocks can be obtained from research investigators, companies, and collections maintained by particular organizations such as the American Type Culture Collection (ATCC). It is recommended that non-pathogenic strains be used when learning the various plating methods. By following the procedures described in this protocol, students should be able to: ● Perform plating procedures without contaminating media. ● Isolate single bacterial colonies by the

  6. Delaminations in composite plates under impact loads

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1991-01-01

    A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to non-penetrating (low velocity) impact of a solid object. The plate may be simply supported, clamped, or free along its edges. A failure model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were then implemented by a computer code (IMPACT-ST) which can be used to estimate the damage initiation load and the locations, shapes, and sizes of the delaminations. Tests were performed measuring the geometries of the delaminations in graphite-epoxy, graphite-toughened epoxy, and graphite-PEEK plates impacted by a projectile with a spherical tip having masses ranging from 0.355 lbm to 0.963 lbm and velocities from 50 in/sec to 225 in/sec. The data were compared to the results of the model, and good agreements were found between the measured and the calculated delamination lengths and widths.

  7. The moving plate capacitor paradox

    NASA Astrophysics Data System (ADS)

    Davis, B. R.; Abbott, D.; Parrondo, J. M. R.

    2000-03-01

    For the first time we describe an apparent paradox concerning a moving plate capacitor driven by thermal noise from a resistor. A demon restores the plates of the capacitor to their original position, only when the voltage across the capacitor is small—hence only small forces are present for the demon to work against. The demon has to work harder than this to avoid the situation of perpetual motion, but the question is how? We explore the concept of a moving plate capacitor, driven by noise, a step further by examining the case where the restoring force on the capacitor plates is provided by a simple spring, rather than some unknown demon. We display simulation results with interesting behavior, particularly where the capacitor plates collide with each other.

  8. SAMI Automated Plug Plate Configuration

    NASA Astrophysics Data System (ADS)

    Lorente, N. P. F.; Farrell, T.; Goodwin, M.

    2013-10-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) is a prototype wide-field system at the Anglo-Australian Telescope (AAT) which uses a plug-plate to mount its 13×61-core imaging fibre bundles (hexabundles) in the optical path at the telescope's prime focus. In this paper we describe the process of determining the positions of the plug-plate holes, where plates contain three or more stacked observation configurations. The process, which up until now has involved several separate processes and has required significant manual configuration and checking, is now being automated to increase efficiency and reduce error. This is carried out by means of a thin Java controller layer which drives the configuration cycle. This layer controls the user interface and the C++ algorithm layer where the plate configuration and optimisation is carried out. Additionally, through the Aladin display package, it provides visualisation and facilitates user verification of the resulting plates.

  9. Present-day plate motions

    NASA Technical Reports Server (NTRS)

    Minster, J. B.; Jordan, T. H.

    1977-01-01

    A data set comprising 110 spreading rates, 78 transform fault azimuths and 142 earthquake slip vectors was inverted to yield a new instantaneous plate motion model, designated RM2. The mean averaging interval for the relative motion data was reduced to less than 3 My. A detailed comparison of RM2 with angular velocity vectors which best fit the data along individual plate boundaries indicates that RM2 performs close to optimally in most regions, with several notable exceptions. On the other hand, a previous estimate (RM1) failed to satisfy an extensive set of new data collected in the South Atlantic Ocean. It is shown that RM1 incorrectly predicts the plate kinematics in the South Atlantic because the presently available data are inconsistent with the plate geometry assumed in deriving RM1. It is demonstrated that this inconsistency can be remedied by postulating the existence of internal deformation with the Indian plate, although alternate explanations are possible.

  10. Plate Interface Rheology, Mechanical Coupling and Accretion during Subduction Infancy

    NASA Astrophysics Data System (ADS)

    Agard, P.; Yamato, P.; Mathieu, S.; Prigent, C.; Guillot, S.; Plunder, A.; Dubacq, B.; Monie, P.; Chauvet, A.

    2015-12-01

    Understanding subduction rheology in both space and time has been a challenge since the advent of plate tectonics. We herein focus on "subduction infancy", that is the first ~1-5 My immediately following subduction nucleation, when a newly born slab penetrates into the upper plate mantle and heats up. The only remnants of this critical yet elusive geodynamic step are thin metamorphic soles, commonly found beneath pristine, 100-1000 km long portions of oceanic lithosphere emplaced on continents (i.e., ophiolites). Through the (i) worldwide compilation of pressure-temperature conditions of metamorphic sole formation augmented by pseudosection thermodynamic modeling, (ii) calculations of the viscosity of materials along the plate interface and (iii) generic numerical thermal models, we provide a conceptual model of dynamic plate interface processes during subduction infancy (and initiation s.l.). We show in particular how major rheological switches across the subduction interface control slab penetration, and the formation of metamorphic soles. Due to the downward progression of hydration and weakening of the mantle wedge with cooling, the lower plate (basalt, sediment) and the upper plate (mantle wedge) rheologies equalize and switch over a restricted temperature-time-depth interval (e.g., at ~800°C and ~1 GPa, during 0.1-2 My, for high-temperature metamorphic sole formation). These switches result in episodes of maximum interplate mechanical coupling, thereby slicing the top of the slab and welding pieces (basalt, sediment) to the base of the mantle wedge. Similar mechanical processes likely apply for the later, deeper accretion and exhumation of high-temperature oceanic eclogites in serpentinite mélanges, or for the accretion of larger tectonic slices. This model provides constraints on the effective rheologies of the crust and mantle and general understanding, at both rock and plate scale, for accretion processes and early slab dynamics.

  11. Plate tectonics, damage and inheritance

    NASA Astrophysics Data System (ADS)

    Bercovici, D. A.; Ricard, Y. R.

    2013-12-01

    The initiation of plate tectonics on Earth is a critical event in our planet's history. The time lag between the first proto subduction about 4Ga, evident in geochemical analysis from ancient cratons, to global tectonics by 3-2.7Ga, suggests that plates and plate boundaries spread globally over a 1Gyr period. We hypothesize that when sufficient lithospheric damage, which promotes shear-localization and long-lived weak zones, combines with transient mantle flow and migrating proto-subduction, it leads to the accumulation of plate boundaries and eventually fully formed tectonic plates driven by subduction alone. We demonstrate this process with an idealized model of pressure-driven flow (wherein a low pressure zone is equivalent to downwelling suction or slab pull) in a lithosphere that self-weakens according to a mylonitic-type polycrystalline grain-damage mechanism (Bercovici and Ricard, Phys. Earth Planet. Int. v.202-203, pp27-55, 2012). In the simplest case, for Earth-like conditions, four successive orthogonal rotations of the driving pressure field yield relic damage zones that are inherited to form a nearly perfect plate, with passive spreading and strike-slip margins that persist and localize further, even as flow is only driven by subduction. For Venus' hotter surface conditions, accumulation and inheritance of damage is negligible; hence only subduction zones survive and plate tectonics does not spread, which is compatible with observations. After plates are developed, continued changes in driving forces combined with inherited damage and weak zones, promote increased tectonic complexity, such as oblique subduction, strike-slip boundaries that are subparallel to plate motion, and spalling of minor and micro plates.

  12. Sub-Plate Overlap Code Documentation

    NASA Technical Reports Server (NTRS)

    Taff, L. G.; Bucciarelli, B.; Zarate, N.

    1997-01-01

    An expansion of the plate overlap method of astrometric data reduction to a single plate has been proposed and successfully tested. Each plate is (artificially) divided into sub-plates which can then be overlapped. This reduces the area of a 'plate' over which a plate model needs to accurately represent the relationship between measured coordinates and standard coordinates. Application is made to non-astrographic plates such as Schmidt plates and to wide-field astrographic plates. Indeed, the method is completely general and can be applied to any type of recording media.

  13. Mantle convection with plates and mobile, faulted plate margins.

    PubMed

    Zhong, S; Gurnis, M

    1995-02-10

    A finite-element formulation of faults has been incorporated into time-dependent models of mantle convection with realistic rheology, continents, and phase changes. Realistic tectonic plates naturally form with self-consistent coupling between plate and mantle dynamics. After the initiation of subduction, trenches rapidly roll back with subducted slabs temporarily laid out along the base of the transition zone. After the slabs have penetrated into the lower mantle, the velocity of trench migration decreases markedly. The inhibition of slab penetration into the lower mantle by the 670-kilometer phase change is greatly reduced in these models as compared to models without tectonic plates. PMID:17813909

  14. Evaluation of a non-cyanide gold plating process for switch tubes

    SciTech Connect

    Norwood, D.P.; Martinez, F.E.

    1996-01-01

    Switch tubes are used in nuclear weapon firing sets and are required to be reliable and impervious to gas permeation for many years. To accomplish this, a gold plated coating of approximately 25 microns is required over all metal surfaces on the tube exterior. The gold has historically been plated using gold cyanide plating chemistry. In this work we proposed to replace the cyanide plating bath with an environmentally friendlier sulfite gold plating bath. Low and high pH sulfite plating chemistries were investigated as possible replacements for the cyanide gold plating chemistry. The low pH plating chemistry demonstrated a gold plated coating which met the high purity, grain size, and hardness requirements for switch tubes. The high pH chemistry was rejected primarily because the hardness of the gold plated coatings was too high and exceeded switch tube coating requirements. A problem with nodule formation on the gold plated surface using the low pH chemistry had to be resolved during this evaluation. The nodule formation was postulated to be produced by generation of SO{sub 2} in the low pH bath causing gold to be precipitated out when the sulfite concentration falls below a minimum level. The problem was resolved by maintaining a higher sulfite concentration and providing an active filtration system during plating. In this initial study, there were no major obstacles found when using a sulfite gold bath for switch tube plating, however, further work is needed on bath control and bath life before adopting it as the primary plating chemistry.

  15. Biomechanics of bone-fracture fixation by stiffness-graded plates in comparison with stainless-steel plates

    PubMed Central

    Ganesh, VK; Ramakrishna, K; Ghista, Dhanjoo N

    2005-01-01

    Background In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress-shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress-shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress-shielding of the layer of the bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. Method In order to address this problem, we propose to use stiffness-graded plates. Accordingly, we have computed (by finite-element analysis) the stress distribution in the fractured bone fixed by composite plates, whose stiffness is graded both longitudinally and transversely. Results It can be seen that the stiffness-graded composite-plates cause less stress-shielding (as an example: at 50% of the healing stage, stress at the fracture interface is compressive in nature i.e. 0.002 GPa for stainless steel plate whereas stiffness graded plates provides tensile stress of 0.002 GPa. This means that stiffness graded plate is allowing the 50% healed bone to participate in loadings). Stiffness-graded plates are more flexible, and hence permit more bending of the fractured bone. This results in higher compressive stresses induced at the fractured faces accelerate bone-healing. On the other hand, away from the fracture interface the reduced stiffness and elastic modulus of the plate causes the neutral axis of the composite structure to be lowered into the bone resulting in the higher tensile stress in the bone-layer underneath the plate, wherein is conducive to the bone preserving its tensile strength. Conclusion Stiffness graded plates (with in-built variable stiffness) are deemed to offer less stress-shielding to the bone, providing higher compressive stress at the fractured interface (to induce accelerated healing) as well as higher tensile

  16. Difficulties encountered removing locked plates

    PubMed Central

    Raja, S; Imbuldeniya, AM; S, Garg; Groom, G

    2012-01-01

    INTRODUCTION Locked plates are commonly used to obtain fixation in periarticular and comminuted fractures. Their use has also gained popularity in repairing fractures in osteoporotic bone. These plates provide stable fixation and promote biological healing. Over the last 3 years, we have used over 150 locked plates with varying success to fix periarticular fractures involving mainly the knee and ankle. In this study, we report our clinical experience and the difficulties encountered when removing locked plates in adult patients with a variety of indications including implant failure, infection, non-union and a palpable symptomatic implant. METHODS A retrospective analysis was performed of patients enrolled prospectively into a database. Included in the study were 36 consecutive adult patients who each underwent the procedure of locked plate removal in a single inner city level 1 trauma centre. Data collected included primary indication for fixation, indication for implant removal, time of the implant in situ, grade of operating surgeon and difficulties encountered during the procedure. RESULTS Implant removal was associated with a complication rate of 47%. The major problems encountered were difficulty in removing the locked screws and the implant itself. A total of ten cold welded screws were found in eight cases. Removal was facilitated by high speed metal cutting burrs and screw removal sets in all but one case, where a decision was made to leave the plate in situ. CONCLUSIONS The majority of studies investigating implant removal and problems encountered in doing so report a relatively high complication rate. With the advent of locking plates and their growing popularity, difficulties are now being seen intra-operatively when removing them. There is a paucity of data, however, specifically directed at locking plate removal. We recommend that surgeons should be aware of the potential complications while removing locked plates. Fluoroscopic control and all

  17. The concept of locking plates.

    PubMed

    Cronier, P; Pietu, G; Dujardin, C; Bigorre, N; Ducellier, F; Gerard, R

    2010-05-01

    After a short historical review of locking bone plates since their inception more than a century ago to the success of the concept less than 15 years ago with today's plates, the authors present the main locking mechanisms in use. In the two broad categories - plates with fixed angulation and those with variable angulation - the screw head is locked in the plate with a locknut by screwing in a threaded chamber on the plate or by screwing through an adapted ring. The authors then provide a concrete explanation, based on simple mechanical models, of the fundamental differences between conventional bone plates and locking plates and why a locking screw system presents greater resistance at disassembly, detailing the role played by the position and number of screws. The advantages of epiphyseal fixation are then discussed, including in cases of mediocre-quality bone. For teaching purposes, the authors also present assembly with an apple fixed with five locking screws withstanding a 47-kg axial load with no resulting disassembly. The principles of plate placement are detailed for both the epiphysis and diaphysis, including the number and position of screws and respect of the soft tissues, with the greatest success assured by the minimally invasive and even percutaneous techniques. The authors then present the advantages of locking plates in fixation of periprosthetic fractures where conventional osteosynthesis often encounters limited success. Based on simplified theoretical cases, the economic impact in France of this type of implant is discussed, showing that on average it accounts for less than 10% of the overall cost of this pathology to society. Finally, the possible problems of material ablation are discussed as well as the means to remediate these problems.

  18. High loading uranium fuel plate

    DOEpatents

    Wiencek, Thomas C.; Domagala, Robert F.; Thresh, Henry R.

    1990-01-01

    Two embodiments of a high uranium fuel plate are disclosed which contain a meat comprising structured uranium compound confined between a pair of diffusion bonded ductile metal cladding plates uniformly covering the meat, the meat having a uniform high fuel loading comprising a content of uranium compound greater than about 45 Vol. % at a porosity not greater than about 10 Vol. %. In a first embodiment, the meat is a plurality of parallel wires of uranium compound. In a second embodiment, the meat is a dispersion compact containing uranium compound. The fuel plates are fabricated by a hot isostatic pressing process.

  19. Plate interactions of Laurussia and Gondwana during the formation of Pangea- Constraints by U-Pb LA-SF-ICP-MS detrital zircon ages of Devonian and Early Carboniferous siliciclastics of the Rheinisches Schiefergebirge (Rhenohercynian zone, Central European

    NASA Astrophysics Data System (ADS)

    Eckelmann, Katja; Nesbor, Heinz-Dieter; Königshof, Peter; Linnemann, Ulf; Hofmann, Mandy; Lange, Jan-Michael; Sagawe, Anja

    2013-04-01

    The Rhenohercynian zone of the Central European Variscides contains top-NW thrusted rock complexes in the area of the Hörre nappe. Further to the north, par-authochthonous volcano-sedimentary complexes of the Lahn and Dill-Eder synclines occur. In our paper, a representative data set of U-Pb LA-SF ICP-MS ages of 1228 detrital zircon grains of Devonian and Lower Carboniferous sandstones from both areas is presented. The data constrain the Middle to Upper Devonian and the Lower Carboniferous siliciclastic and volcano-sedimentary complexes of the Hörre nappe to be allochtonous. The cluster of U-Pb ages of detrital zircon grains point to a provenance of the debris from the Saxo-Thuringian zone and rock complexes of the Mid-German Crystalline zone, which were formerly related to the latter one. A long-distance top-NW directed transport of the nappe complex in the Hörre nappe is required by our new data set. The zircon populations derived from the Saxo-Thuringian zone are representative for a Gondwanan hinterland and characterised by age clusters of ~530-700 Ma, ~1,8-2.2 Ga, ~2.5-2.7 Ga, and ~3.0-3.4 Ga. In a palaeogeographic view, the Saxo-Thuringian zone formed during Devonian to Lower Carboniferous time at the southern margin of the Rheic Ocean. A Lower Devonian sandstone sample from the par-authochtonous Lahn-Dill-Eder syncline shows a provenance, which is representative for Laurussia. Most of that debris seems to be derived from Baltica and Avalonia, two important parts of Laurussia. U-Pb zircon ages cluster at ~ 400-450 Ma, 540-650 Ma, 1.0-1.2 Ga, ~1.4-1.5 Ga, ~1.7-2.2 Ga, and 2.3-2.9 Ga. In terms of a palaeogeographic relation, these samples represent a sedimentary unit which was deposited at the northern margin of the Rheic Ocean at the edge of Laurussia facing to the south. Our data set constrains a top-SE directed subduction of the oceanic crust of the Rheic Ocean during its final closure and the formation of supercontinent Pangea.

  20. Origin of plate tectonics: Grain-damage, inheritance and hysteresis

    NASA Astrophysics Data System (ADS)

    Bercovici, D.; Ricard, Y. R.

    2015-12-01

    The emergence of plate tectonics is enigmatic because of the lack of observations in the early Archean as well as the challenge of understanding how plates form. The damage theory of lithospheric weakening by grain-reduction provides a physical framework for plate generation. This model builds on grain-scale physics to describe planetary-scale processes, and is consistent with lab and field observations of polycrystalline rocks and lithospheric mylonites. Grain-damage accounts for the evolution of damage and healing by grain growth, hence predicts plate boundary formation and longevity, and how they depend on surface conditions. The establishment of global plate tectonics likely started between >4Ga and 2.7Ga, and may have taken over a billion years to develop. Under Earth-like conditions, grain-damage combined with intermittent Archean protosubduction produces persistent weak zones that accumulate into well developed plates by 3Ga. However, Venus' hotter surface promotes healing, suppresses damage and inhibits weak zone accumulation, which suggests why plate tectonics failed to spread on our sister planet. New work posits that interface damage is possibly suppressed at moderate grain-size; this induces a hysteresis loop wherein three equilibrium deformation branches coexist. These branches include a stable large-grain, weakly-deforming state in dislocation creep, a stable small-grain rapidly-deforming state in diffusion creep analogous to mylonites, and an unstable intermediate-grain state. At the right conditions, a lithosphere can acquire two stable deformation states characteristic of plate tectonics; i.e., both slowly deforming plate interiors and rapidly deforming plate boundaries can co-exist. Earth currently sits inside the hysteresis loop and can have coexisting deformation states, while Venus sits at the end of the loop where only the weakly deforming branch dominates. The hot post-Hadean Earth might have had peak deformation only on the weakly

  1. Plate Motions and the Viscosity Structure of the Mantle

    NASA Astrophysics Data System (ADS)

    Stein, C.; Hansen, U.

    2007-12-01

    The viscosity structure of the Earth's mantle is likely to play an important role with respect to the motion of the lithospheric plates. A zone of low viscosity in the upper mantle has been proposed to facilitate plate motion. Another typical feature of the viscosity profile in the mantle is a significant viscosity increase at greater depth. We have employed a three-dimensional mantle convection model to explore the relation between the appearance of plate motion and the viscosity structure of the mantle beneath. With this model we further elucidate the mechanisms relevant for the formation of a low or high viscosity zone. The model allows for a complex rheology of the fluid (strong temperature, pressure and stress dependence of the viscosity) and can so account for the self- consistent formation of plates at the surface of the convecting mantle. As a general result we observe that a delicate balance between temperature, stress and pressure dependence of the viscosity is required to obtain stable plate motion and that within this balance the viscosity shows a local minimum at shallow depth (low viscosity zone) and a local maximum at greater depth.

  2. Carbon-assisted flyer plates

    DOEpatents

    Stahl, D.B.; Paisley, D.L.

    1994-04-12

    A laser driven flyer plate is described utilizing an optical fiber connected to a laser. The end of the optical fiber has a layer of carbon and a metal layer deposited onto it. The carbon layer provides the laser induced plasma which is superior to the plasma produced from most metals. The carbon layer plasma is capable of providing a flatter flyer plate, converting more of the laser energy to driving plasma, promoting a higher flyer plate acceleration, and providing a more uniform pulse behind the plate. In another embodiment, the laser is in optical communication with a substrate onto which a layer of carbon and a layer of metal have been deposited. 2 figures.

  3. The multigap resistive plate chamber

    SciTech Connect

    Zeballos, E. Cerron; Crotty, I.; Hatzifotiadou, D.; Valverde, J. Lamas; Neupane, S.; Williams, M. C. S.; Zichichi, A.

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  4. Tectonics: Changing of the plates

    NASA Astrophysics Data System (ADS)

    Brandon, Alan

    2016-10-01

    The composition of Earth's crust depends on the style of plate tectonics and of the melting regimes in the mantle. Analyses of the oldest identified rocks suggest that these styles and the resulting crust have changed over Earth's history.

  5. Quaternions as astrometric plate constants

    NASA Technical Reports Server (NTRS)

    Jefferys, William H.

    1987-01-01

    A new method for solving problems in relative astrometry is proposed. In it, the relationship between the measured quantities and the components of the position vector of a star is modeled using quaternions, in effect replacing the plate constants of a standard four-plate-constant solution with the four components of a quaternion. The method allows a direct solution for the position vectors of the stars, and hence for the equatorial coordinates. Distortions, magnitude, and color effects are readily incorporated into the formalism, and the method is directly applicable to overlapping-plate problems. The advantages of the method include the simplicity of the resulting equations, their freedom from singularities, and the fact that trigonometric functions and tangential point transformations are not needed to model the plate material. A global solution over the entire sky is possible.

  6. Pulse plating of nickel deposits

    SciTech Connect

    Stimetz, C.J.; Stevenson, M.F.

    1980-02-01

    Pulse plated and conventional nickel deposits have been compared for differences in morphology, mechanical properties, and microstructure. The deposits were obtained from nickel sulfamate, nickel chloride, and Watts nickel plating solutions. No significant differences were found in the direct and pulse current deposits from the sulfamate and chloride solutions; however, significant differences in microstructure, yield strength, and microhardness were observed in deposits from the Watts nickel solution.

  7. Impact on multilayered composite plates

    NASA Technical Reports Server (NTRS)

    Kim, B. S.; Moon, F. C.

    1977-01-01

    Stress wave propagation in a multilayer composite plate due to impact was examined by means of the anisotropic elasticity theory. The plate was modelled as a number of identical anisotropic layers and the approximate plate theory of Mindlin was then applied to each layer to obtain a set of difference-differential equations of motion. Dispersion relations for harmonic waves and correction factors were found. The governing equations were reduced to difference equations via integral transforms. With given impact boundary conditions these equations were solved for an arbitrary number of layers in the plate and the transient propagation of waves was calculated by means of a Fast Fourier Transform algorithm. The multilayered plate problem was extended to examine the effect of damping layers present between two elastic layers. A reduction of the interlaminar normal stress was significant when the thickness of damping layer was increased but the effect was mostly due to the softness of the damping layer. Finally, the problem of a composite plate with a crack on the interlaminar boundary was formulated.

  8. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-01

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction. PMID:12364804

  9. How mantle slabs drive plate tectonics.

    PubMed

    Conrad, Clinton P; Lithgow-Bertelloni, Carolina

    2002-10-01

    The gravitational pull of subducted slabs is thought to drive the motions of Earth's tectonic plates, but the coupling between slabs and plates is not well established. If a slab is mechanically attached to a subducting plate, it can exert a direct pull on the plate. Alternatively, a detached slab may drive a plate by exciting flow in the mantle that exerts a shear traction on the base of the plate. From the geologic history of subduction, we estimated the relative importance of "pull" versus "suction" for the present-day plates. Observed plate motions are best predicted if slabs in the upper mantle are attached to plates and generate slab pull forces that account for about half of the total driving force on plates. Slabs in the lower mantle are supported by viscous mantle forces and drive plates through slab suction.

  10. Geometry of the Cocos Plate Under North American Plate

    NASA Astrophysics Data System (ADS)

    Perez-Campos, X.

    2015-12-01

    The Cocos plate subducts under the North American plate with a complex geometry, and previous seismicity studies revealed some of this complexity. However, details of the geometry and the depth that the plate penetrates werelargely unknown. Since 2004, temporary experiments and the expansion of the permanent network of the Servicio Sismológico Nacional (SSN, Mexican National Seismological Service) have improved resolution of the plate geometry and have helped to map its descent into the upper mantle. Going from northwest to southeast, the Cocos plate appears to be fragmenting into north and south segments. The north segment subducts with an angle of ~30º and the south with an angle of ~10-15º. The transition is smooth near the trench and progresses to a tear at depth; this coincides with the projection of the Orozco Fracture Zone to depth. Also, this transition marks the limit of the presence to the south of an ultra slow velocity layer (USL) on top of the slab.South of this transition, the Cocos plate subducts horizontally , underplating the North American plate for a distance of ~140 to ~300 km from the trench. Along this horizontal region, silent slow events (SSE) and tectonic tremor (TT) have been observed. At a distance of 300 km from the trench (beneath central Mexico), the plate dives into the mantle with an angle of 76º to a depth of 500 km. This geometry changes abruptly to the south, marking the eastern limit of the USL. This change seems to be also characterized by a tear on the slab. Finally to the south, the Cocos plate subducts with a constant angle of 26º. This presentation summarizes the work of many contributors including A. Arciniega-Ceballos, M. Brudzinski, E. Cabral-Cano, T. Chen, R. Clayton,F. Cordoba-Montiel,P. Davis,S. Dougherty,F. Green, M. Gurnis, D. V. Helmberger, A. Husker,A. Iglesias, Y. Kim, V. Manea, D. Melgar, M. Rodríguez-Domínguez,S. K. Singh, T.-R. A. Song, C. M. Valdés-González, D. Valencia-Cabrera

  11. Plate mode velocities in graphite/epoxy plates

    NASA Technical Reports Server (NTRS)

    Prosser, W. H.; Gorman, M. R.

    1994-01-01

    Measurements of the velocities of the extensional and flexural plate modes were made along three directions of propagation in four graphite/epoxy composite plates. The acoustic signals were generated by simulated acoustic emission events (pencil lead breaks or Hsu-Neilson sources) and detected by by broadband ultrasonic transducers. The first arrival of the extensional plate mode, which is nondispersive at low frequencies, was measured at a number of different distances from the source along the propagation direction of interest. The velocity was determined by plotting the distance versus arrival time and computing its slope. Because of the large dispersion of the flexural mode, a Fourier phase velocity technique was used to characterize this mode. The velocity was measured up to a frequency of 160 kHz. Theoretical predictions of the velocities of these modes were also made and compared with experimental observations. Classical plate theory yields good agreement with the measured extensional velocities. For predictions of the dispersion of the flexural mode, Mindlin plates theory, which includes the effects of shear deformation and rotatory inertia was shown to give better agreement with the experimental measurements.

  12. Application of atomic layer deposited microchannel plates to imaging photodetectors with high time resolution

    NASA Astrophysics Data System (ADS)

    Siegmund, O. H. W.; McPhate, J. B.; Tremsin, A. S.; Vallerga, J. V.; Ertley, C. D.; Richner, N. J.; Gerard, T. M.; Frisch, H. J.; Elam, J. W.; Mane, A. U.; Wagner, R. G.; Minot, M. J.; O`Mahony, A.; Craven, C. A.

    2015-07-01

    Novel microchannel plates have been constructed using borosilicate glass micro-capillary array substrates with 20 μm and 10 μm pores and coated with resistive, and secondary electron emissive, layers by atomic layer deposition. Microchannel plates in 33 mm, 50 mm and 20 cm square formats have been made and tested. Although their amplification, imaging, and timing properties are comparable to standard glass microchannel plates, the background rates and lifetime characteristics are considerably improved. Sealed tube detectors based on the Planacon tube, and a 25 mm cross delay line readout tube with a GaN(Mg) opaque photocathode deposited on borosilicate microchannel plates have been fabricated. Considerable progress has also been made with 20 cm microchannel plates for a 20 cm format sealed tube sensor with strip-line readout that is being developed for Cherenkov light detection.

  13. PTH Receptor Signaling in Osteoblasts Regulates Endochondral Vascularization in Maintenance of Postnatal Growth Plate

    PubMed Central

    Qiu, Tao; Xian, Lingling; Crane, Janet; Wen, Chunyi; Hilton, Matthew; Lu, William; Newman, Peter; Cao, Xu

    2016-01-01

    Longitudinal growth of postnatal bone requires precise control of growth plate cartilage chondrocytes and subsequent osteogenesis and bone formation. Little is known about the role of angiogenesis and bone remodeling in maintenance of cartilaginous growth plate. Parathyroid hormone (PTH) stimulates bone remodeling by activating PTH receptor (PTH1R). Mice with conditional deletion of PTH1R in osteoblasts showed disrupted trabecular bone formation. The mice also exhibited postnatal growth retardation with profound defects in growth plate cartilage, ascribable predominantly to a decrease in number of hypertrophic chondrocytes, resulting in premature fusion of the growth plate and shortened long bones. Further characterization of hypertrophic zone and primary spongiosa revealed that endochondral angiogenesis and vascular invasion of the cartilage were impaired, which was associated with aberrant chondrocyte maturation and cartilage development. These studies reveal that PTH1R signaling in osteoblasts regulates cartilaginous growth plate for postnatal growth of bone. PMID:25196529

  14. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries. PMID:16057188

  15. Electrodeposition process reduces cost of cold plates

    NASA Technical Reports Server (NTRS)

    Ruppe, E. P.

    1980-01-01

    Efficient nickel heat-exchanger cold plates can be fabricated less expensively than stainless steel plates. If adapted to mass production, it is estimated that nickel cold plates might be made for about 30 percent less than stainless-steel plates.

  16. 49 CFR 451.23 - Plate specifications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 6 2013-10-01 2013-10-01 false Plate specifications. 451.23 Section 451.23... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS TESTING AND APPROVAL OF CONTAINERS Safety Approval Plate § 451.23 Plate specifications. (a) The safety approval plate must be of the size and in the...

  17. 49 CFR 451.23 - Plate specifications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Plate specifications. 451.23 Section 451.23... SECURITY SAFETY APPROVAL OF CARGO CONTAINERS TESTING AND APPROVAL OF CONTAINERS Safety Approval Plate § 451.23 Plate specifications. (a) The safety approval plate must be of the size and in the...

  18. Plate tectonics of the Mediterranean region.

    PubMed

    McKenzie, D P

    1970-04-18

    The seismicity and fault plane solutions in the Mediterranean area show that two small rapidly moving plates exist in the Eastern Mediterranean, and such plates may be a common feature of contracting ocean basins. The results show that the concepts of plate tectonics apply to instantaneous motions across continental plate boundaries.

  19. Polar standstill of the mid-cretaceous pacific plate and its geodynamic implications.

    PubMed

    Tarduno, J A; Sager, W W

    1995-08-18

    Paleomagnetic data from the Mid-Cretaceous Mountains suggest that Pacific plate motion during the Early to mid-Cretaceous was slow, less than 0.3 degree per year, resembling the polar standstill observed in coeval rocks of Eurasia and North America. There is little evidence for a change in plate motion that could have precipitated the major volcanic episode of the early Aptian that is marked by the formation of the Ontong Java Plateau. During the volcanism, oceanic plates bordering the Pacific plate moved rapidly. Large-scale northward motion of the Pacific plate began after volcanism ceased. This pattern suggests that mantle plume volcanism exerted control on plate tectonics in the Cretaceous Pacific basin. PMID:17807731

  20. Polar standstill of the mid-cretaceous pacific plate and its geodynamic implications.

    PubMed

    Tarduno, J A; Sager, W W

    1995-08-18

    Paleomagnetic data from the Mid-Cretaceous Mountains suggest that Pacific plate motion during the Early to mid-Cretaceous was slow, less than 0.3 degree per year, resembling the polar standstill observed in coeval rocks of Eurasia and North America. There is little evidence for a change in plate motion that could have precipitated the major volcanic episode of the early Aptian that is marked by the formation of the Ontong Java Plateau. During the volcanism, oceanic plates bordering the Pacific plate moved rapidly. Large-scale northward motion of the Pacific plate began after volcanism ceased. This pattern suggests that mantle plume volcanism exerted control on plate tectonics in the Cretaceous Pacific basin.

  1. Beyond plate tectonics - Looking at plate deformation with space geodesy

    NASA Technical Reports Server (NTRS)

    Jordan, Thomas H.; Minster, J. Bernard

    1988-01-01

    The requirements that must be met by space-geodetic systems in order to constrain the horizontal secular motions associated with the geological deformation of the earth's surface are explored. It is suggested that in order to improve existing plate-motion models, the tangential components of relative velocities on interplate baselines must be resolved to an accuracy of less than 3 mm/yr. Results indicate that measuring the velocities between crustal blocks to + or - 5 mm/yr on 100-km to 1000-km scales can produce geologically significant constraints on the integrated deformation rates across continental plate-boundary zones such as the western United States.

  2. Plating on some difficult-to-plate metals and alloys

    SciTech Connect

    Dini, J.W.; Johnson, H.R.

    1980-02-01

    Electrodeposition of coatings on metals such as beryllium, beryllium-copper, Kovar, lead, magnesium, thorium, titanium, tungsten, uranium, zirconium, and their alloys can be problematic. This is due in most cases to a natural oxide surface film that readily reforms after being removed. The procedures we recommend for plating on these metals rely on replacing the oxide film with a displacement coating, or etching to allow mechanical keying between the substrate and plated deposit. The effectiveness of the procedures is demonstrated by interface bond strengths found in ring-shear and conical-head tensile tests.

  3. Plates for vacuum thermal fusion

    DOEpatents

    Davidson, James C.; Balch, Joseph W.

    2002-01-01

    A process for effectively bonding arbitrary size or shape substrates. The process incorporates vacuum pull down techniques to ensure uniform surface contact during the bonding process. The essence of the process for bonding substrates, such as glass, plastic, or alloys, etc., which have a moderate melting point with a gradual softening point curve, involves the application of an active vacuum source to evacuate interstices between the substrates while at the same time providing a positive force to hold the parts to be bonded in contact. This enables increasing the temperature of the bonding process to ensure that the softening point has been reached and small void areas are filled and come in contact with the opposing substrate. The process is most effective where at least one of the two plates or substrates contain channels or grooves that can be used to apply vacuum between the plates or substrates during the thermal bonding cycle. Also, it is beneficial to provide a vacuum groove or channel near the perimeter of the plates or substrates to ensure bonding of the perimeter of the plates or substrates and reduce the unbonded regions inside the interior region of the plates or substrates.

  4. Thermal Stress Cracking of Slide-Gate Plates in Steel Continuous Casting

    NASA Astrophysics Data System (ADS)

    Lee, Hyoung-Jun; Thomas, Brian G.; Kim, Seon-Hyo

    2016-04-01

    The slide-gate plates in a cassette assembly control the steel flow through the tundish nozzle, and may experience through-thickness cracks, caused by thermal expansion and/or mechanical constraint, leading to air aspiration and safety concerns. Different mechanisms for common and rare crack formation are investigated with the aid of a three-dimensional finite-element model of thermal mechanical behavior of the slide-gate plate assembly during bolt pretensioning, preheating, tundish filling, casting, and cooling stages. The model was validated with previous plant temperature measurements of a ladle plate during preheating and casting, and then applied to a typical tundish-nozzle slide-gate assembly. The formation mechanisms of different types of cracks in the slide-gate plates are investigated using the model and evaluated with actual slide-gate plates at POSCO. Common through-thickness radial cracks, found in every plate, are caused during casting by high tensile stress on the outside surfaces of the plates, due to internal thermal expansion. In the upper plate, these cracks may also arise during preheating or tundish filling. Excessive bolt tightening, combined with thermal expansion during casting may cause rare radial cracks in the upper and lower plates. Rare radial and transverse cracks in middle plate appear to be caused during tundish filling by impingement of molten steel on the middle of the middle plate that generates tensile stress in the surrounding refractory. The mechanical properties of the refractory, the bolt tightening conditions, and the cassette/plate design are all important to service life.

  5. Multiregional evaluation of the SimPlate heterotrophic plate count method compared to the standard plate count agar pour plate method in water.

    PubMed

    Jackson, R W; Osborne, K; Barnes, G; Jolliff, C; Zamani, D; Roll, B; Stillings, A; Herzog, D; Cannon, S; Loveland, S

    2000-01-01

    A new SimPlate heterotrophic plate count (HPC) method (IDEXX Laboratories, Westbrook, Maine) was compared with the pour plate method at 35 degrees C for 48 h. Six laboratories tested a total of 632 water samples. The SimPlate HPC method was found to be equivalent to the pour plate method by regression analysis (r = 0. 95; y = 0.99X + 0.06).

  6. Insert metering plates for gas turbine nozzles

    DOEpatents

    Burdgick, Steven S.; Itzel, Gary; Chopra, Sanjay; Abuaf, Nesim; Correia, Victor H.

    2004-05-11

    The invention comprises a metering plate which is assembled to an impingement insert for use in the nozzle of a gas turbine. The metering plate can have one or more metering holes and is used to balance the cooling flow within the nozzle. A metering plate with multiple holes reduces static pressure variations which result from the cooling airflow through the metering plate. The metering plate can be assembled to the insert before or after the insert is inserted into the nozzle.

  7. Elastoacoustic response of laminated plates

    NASA Astrophysics Data System (ADS)

    Kolar, Ramesh

    2005-04-01

    The application of composite materials in the aerospace and naval structures has increased enormously due to high specific strength and specific stiffness afforded by these materials. In this paper a formulation is developed based on Hamilton's Principle and laminated composite plate theory to study the elasto-acoustical response of composite plates under heavy fluid loadings. The formulation starts by using Hamilton's principle in conjunction with shear deformable theory of laminated composite plates. The acoustic pressure described by wave equation is computed similar to Sandman and Nelisse. Using the Rayleigh Ritz method and symbolic mathematics for evaluation of integrals, the formulation provides efficient approach for the problem defined. Typical results include radiation impedance as a function of driving frequency, vibroacoustic indicators such as radiated sound power and mean square velocity for a model problem. Such results are very important in studying constrained layer damping when viscolastic dampers are used in structural components.

  8. Custom Multiwell Plate Design for Rapid Assembly of Photopatterned Hydrogels.

    PubMed

    Ahmed, Naveed; Schober, Joseph; Hill, Lindsay; Zustiak, Silviya P

    2016-06-01

    The extracellular matrix provides both mechanical support and biochemical cues that influence cellular behavior. Matrix stiffness, in particular, has been found to regulate cellular morphology, motility, proliferation, differentiation, and drug responses among other behaviors. Thus, biomaterial platforms that exhibit wide range of stiffness and are available in a semi high-throughput format such as a multiwell plate would be useful for elucidating cell-substrate relationships. Polyacrylamide (PA) gels have been widely used as cell platforms since they span a range of stiffness between 0.3 and 300 kPa in Young's modulus, which encompasses all soft tissues. However, PA gels are time consuming and labor intensive to prepare, and are not amenable to a multiwell plate format. In this study, we present a novel custom multiwell plate design that allows for a one-step stiffness assay assembly that reduces preparation time and labor intensity by several fold. Gel stiffness is controlled by ultraviolet light intensity and exposure time to achieve a wide stiffness range from a single gel precursor solution. The geometry of the gels is defined by a custom photomask and gel thickness is controlled by spacers. A multiwell plate upper structure is designed similar to a regular multiwell plate such that a gel fits in each well and cells and media are added on top. The upper structure design allows for adequate gas exchange and minimum evaporation. Comparison between cell behaviors seeded in the custom and a standard multiwell plate demonstrated the suitability of the design as a cell culture platform. In summary, we describe and validate a novel custom design for an easy and rapid assembly of photopolymerizable PA-based stiffness assay. PMID:27059131

  9. Optimization of magnetically accelerated, ultra-high velocity aluminum flyer plates for use in plate impact, shock wave experiments.

    SciTech Connect

    Cochrane, Kyle Robert; Knudson, Marcus D.; Slutz, Stephen A.; Lemke, Raymond William; Davis, J. P.; Harjes, Henry Charles III; Giunta, Anthony Andrew; Bliss, David Emery

    2005-05-01

    The intense magnetic field produced by the 20 MA Z accelerator is used as an impulsive pressure source to accelerate metal flyer plates to high velocity for the purpose of performing plate impact, shock wave experiments. This capability has been significantly enhanced by the recently developed pulse shaping capability of Z, which enables tailoring the rise time to peak current for a specific material and drive pressure to avoid shock formation within the flyer plate during acceleration. Consequently, full advantage can be taken of the available current to achieve the maximum possible magnetic drive pressure. In this way, peak magnetic drive pressures up to 490 GPa have been produced, which shocklessly accelerated 850 {micro}m aluminum (6061-T6) flyer plates to peak velocities of 34 km/s. We discuss magnetohydrodynamic (MHD) simulations that are used to optimize the magnetic pressure for a given flyer load and to determine the shape of the current rise time that precludes shock formation within the flyer during acceleration to peak velocity. In addition, we present results pertaining to plate impact, shock wave experiments in which the aluminum flyer plates were magnetically accelerated across a vacuum gap and impacted z-cut, {alpha}-quartz targets. Accurate measurements of resulting quartz shock velocities are presented and analyzed through high-fidelity MHD simulations enhanced using optimization techniques. Results show that a fraction of the flyer remains at solid density at impact, that the fraction of material at solid density decreases with increasing magnetic pressure, and that the observed abrupt decrease in the quartz shock velocity is well correlated with the melt transition in the aluminum flyer.

  10. License Plate Recognition System for Indian Vehicles

    NASA Astrophysics Data System (ADS)

    Sanap, P. R.; Narote, S. P.

    2010-11-01

    We consider the task of recognition of Indian vehicle number plates (also called license plates or registration plates in other countries). A system for Indian number plate recognition must cope with wide variations in the appearance of the plates. Each state uses its own range of designs with font variations between the designs. Also, vehicle owners may place the plates inside glass covered frames or use plates made of nonstandard materials. These issues compound the complexity of automatic number plate recognition, making existing approaches inadequate. We have developed a system that incorporates a novel combination of image processing and artificial neural network technologies to successfully locate and read Indian vehicle number plates in digital images. Commercial application of the system is envisaged.

  11. Corrosion resistant metallic bipolar plate

    DOEpatents

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  12. Comment on "Intermittent plate tectonics?".

    PubMed

    Korenaga, Jun

    2008-06-01

    Silver and Behn (Reports, 4 January 2008, p. 85) proposed that intermittent plate tectonics may resolve a long-standing paradox in Earth's thermal evolution. However, their analysis misses one important term, which subsequently brings their main conclusion into question. In addition, the Phanerozoic eustasy record indicates that the claimed effect of intermittency is probably weak.

  13. Troubleshooting plated-wire memories

    NASA Technical Reports Server (NTRS)

    Baker, C. M.; Bright, T. M.; Constable, R. C.

    1979-01-01

    Faults in plated wire memories are identified and located from outside of system by applying electrical impulses and analyzing their reflectance in technique of Time-Domain Reflectometry (TDR). Intermittent faults are easier to find because memory system is not disturbed by probing or disassembly.

  14. The seismotectonics of plate boundaries

    NASA Technical Reports Server (NTRS)

    Berger, J.; Brune, J. N.; Goodkind, J.; Wyatt, F.; Agnew, D. C.; Beaumont, C.

    1981-01-01

    Research on the seismotectonics of plate boundaries is summarized. Instrumental development and an observational program designed to study various aspects of the seismotectonics of southern California and the northern Gulf of California are described. A unique superconducting gravimeter was further developed and supported under this program for deployment and operation at several sites. Work on Earth tides is also discussed.

  15. Plated wire random access memories

    NASA Technical Reports Server (NTRS)

    Gouldin, L. D.

    1975-01-01

    A program was conducted to construct 4096-work by 18-bit random access, NDRO-plated wire memory units. The memory units were subjected to comprehensive functional and environmental tests at the end-item level to verify comformance with the specified requirements. A technical description of the unit is given, along with acceptance test data sheets.

  16. Double-Plate Penetration Equations

    NASA Technical Reports Server (NTRS)

    Hayashida, K. B.; Robinson, J. H.

    2000-01-01

    This report compares seven double-plate penetration predictor equations for accuracy and effectiveness of a shield design. Three of the seven are the Johnson Space Center original, modified, and new Cour-Palais equations. The other four are the Nysmith, Lundeberg-Stern-Bristow, Burch, and Wilkinson equations. These equations, except the Wilkinson equation, were derived from test results, with the velocities ranging up to 8 km/sec. Spreadsheet software calculated the projectile diameters for various velocities for the different equations. The results were plotted on projectile diameter versus velocity graphs for the expected orbital debris impact velocities ranging from 2 to 15 km/sec. The new Cour-Palais double-plate penetration equation was compared to the modified Cour-Palais single-plate penetration equation. Then the predictions from each of the seven double-plate penetration equations were compared to each other for a chosen shield design. Finally, these results from the equations were compared with test results performed at the NASA Marshall Space Flight Center. Because the different equations predict a wide range of projectile diameters at any given velocity, it is very difficult to choose the "right" prediction equation for shield configurations other than those exactly used in the equations' development. Although developed for various materials, the penetration equations alone cannot be relied upon to accurately predict the effectiveness of a shield without using hypervelocity impact tests to verify the design.

  17. Composite transform-convergent plate boundaries: description and discussion

    USGS Publications Warehouse

    Ryan, H.F.; Coleman, P.J.

    1992-01-01

    The leading edge of the overriding plate at an obliquely convergent boundary is commonly sliced by a system of strike-slip faults. This fault system is often structurally complex, and may show correspondingly uneven strain effects, with great vertical and translational shifts of the component blocks of the fault system. The stress pattern and strain effects vary along the length of the system and change through time. These margins are considered to be composite transform-convergent (CTC) plate boundaries. Examples are given of structures formed along three CTC boundaries: the Aleutian Ridge, the Solomon Islands, and the Philippines. The dynamism of the fault system along a CTC boundary can enhance vertical tectonism and basin formation. This concept provides a framework for the evaluation of petroleum resources related to basin formation, and mineral exploration related to igneous activity associated with transtensional processes. ?? 1992.

  18. Consecutive plate acoustic suppressor apparatus and methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony (Inventor)

    1992-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  19. Consecutive Plate Acoustic Suppressor Apparatus and Methods

    NASA Technical Reports Server (NTRS)

    Doychak, Joseph (Inventor); Parrott, Tony L. (Inventor)

    1993-01-01

    An apparatus and method for suppressing acoustic noise utilizes consecutive plates, closely spaced to each other so as to exploit dissipation associated with sound propagation in narrow channels to optimize the acoustic resistance at a liner surface. The closely spaced plates can be utilized as high temperature structural materials for jet engines by constructing the plates from composite materials. Geometries of the plates, such as plate depth, shape, thickness, inter-plate spacing, arrangement, etc., can be selected to achieve bulk material-like behavior.

  20. Avionics Box Cold Plate Damage Prevention

    NASA Technical Reports Server (NTRS)

    Stambolian, Damon B.; Larchar, Steven W.; Henderson, Gena; Tran, Donald; Barth, Tim

    2012-01-01

    Problem Introduction: 1. Prevent Cold Plate Damage in Space Shuttle. 1a. The number of cold plate problems had increased from an average of 16.5 per/year between 1990 through 2000, to an average of 39.6 per year between 2001through 2005. 1b. Each complete set of 80 cold plates cost approximately $29 million, an average of $362,500 per cold plate. 1c It takes four months to produce a single cold plate. 2. Prevent Cold Plate Damage in Future Space Vehicles.

  1. Evaluation of an automated agar plate streaker.

    PubMed Central

    Tilton, R C; Ryan, R W

    1978-01-01

    An automated agar plate streaker was evaluated. The Autostreaker mechanizes the agar plate streaking process by providing storage for plates, labeling and streaking one or more plates for either isolation or quantitation, and stacking in one of several racks for subsequent incubation. Results showed the Autostreaker to produce agar plates with well-separated colonies and accurate colony counts. A total of 1,930 clinical specimens were processed either in parallel with manual methods or solely by the Autostreaker. Technologist acceptance of machine-streaked plates was outstanding. Images PMID:348722

  2. A new approach to large area microchannel plate manufacture

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Methods of manufacture of twisted single elements as the base for producing microchannel plates (MCP) are discussed. Initial evaluations validated the off-axis channel concept and no technological roadblocks were identified which would prevent fabrication of high gain, high spatial resolution, large format MCP's using this technique. The first MP's have operated at stable gains of 3 million with pulse height resolution superior to results obtained by standard chevron MCP's.

  3. Perfused Multiwell Plate for 3D Liver Tissue Engineering

    PubMed Central

    Domansky, Karel; Inman, Walker; Serdy, James; Dash, Ajit; Lim, Matthew H. M.

    2014-01-01

    In vitro models that capture the complexity of in vivo tissue and organ behaviors in a scalable and easy-to-use format are desirable for drug discovery. To address this, we have developed a bioreactor that fosters maintenance of 3D tissue cultures under constant perfusion and we have integrated multiple bioreactors into an array in a multiwell plate format. All bioreactors are fluidically isolated from each other. Each bioreactor in the array contains a scaffold that supports formation of hundreds of 3D microscale tissue units. The tissue units are perfused with cell culture medium circulated within the bioreactor by integrated pneumatic diaphragm micropumps. Electronic controls for the pumps are kept outside the incubator and connected to the perfused multiwell by pneumatic lines. The docking design and open-well bioreactor layout make handling perfused multiwell plates similar to using standard multiwell tissue culture plates. A model of oxygen consumption and transport in the circulating culture medium was used to predict appropriate operating parameters for primary liver cultures. Oxygen concentrations at key locations in the system were then measured as a function of flow rate and time after initiation of culture to determine oxygen consumption rates. After seven days in culture, tissue formed from cells seeded in the perfused multiwell reactor remained functionally viable as assessed by immunostaining for hepatocyte and liver sinusoidal endothelial cell (LSEC) phenotypic markers. PMID:20024050

  4. Development of Reduction Technique of Thermal Stress Induced in Steel Plate Bonded by CFRP Plates

    NASA Astrophysics Data System (ADS)

    Ishikawa, Toshiyuki; Hattori, Atsushi; Kawano, Hirotaka; Nagao, Takashi; Kobayashi, Akira

    In CFRP bonded onto steel plate, thermal stress is induced in steel plate by temperature change, due to difference in coefficients of thermal expansion between steel and CFRP. In this study, reduction technique of the thermal stress in steel plate, which is additional bonding of aluminum alloy plates, is proposed. Namely, the coefficient of thermal expansion of composite plate consisted of CFRP and aluminum plates is designed as that of steel. In this research, to verify the effectiveness of developed method, heat tests of CFRP and aluminum plates bonded onto steel plate were carried out. As a result of the tests, infinitesimal thermal stresses in steel plate with CFRP and aluminum plates were measured while large thermal stresses were measured in conventional CFRP bonded onto steel plate. Additionally, to confirm the test results, numerical analysis was also carried out.

  5. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5 track where timber crossties are in use there shall be tie plates under the running rails on at least eight...

  6. Epiphyseal plate transplantation: an historical review.

    PubMed

    Boyer, M I; Bray, P W; Bowen, C V

    1994-12-01

    Non-vascularized and vascularized transplantation of epiphyseal plate autografts have been performed both clinically and experimentally for over 100 years. However, the ultimate clinical goal of vascularized transplantation of epiphyseal plate allografts for paediatric extremity reconstruction remains elusive, due primarily to the lack of suitably nontoxic techniques to prevent graft rejection. We have summarized the published clinical and experimental investigations of vascularized epiphyseal plate transplantation, and organized the experiments and clinical operations into four main groups: (1) local vascular studies on unmanipulated epiphyseal plates, (2) studies of epiphyseal plate behaviour after orthotopic replantation, (3) studies of epiphyseal plate behaviour after heterotopic transplantation, and (4) studies of epiphyseal plate behaviour after allograft transplantation. Prior investigations into the non-vascularized transplantation of epiphyseal plate autografts and allografts are presented as background. These groups of studies serve as the building blocks for the more clinically applicable experimental investigations outlined in the final section of this review. PMID:7697285

  7. Maps, Plates, and Mount Saint Helens.

    ERIC Educational Resources Information Center

    Lary, Barbara E.; Krockover, Gerald H.

    1987-01-01

    Describes a laboratory activity on plate tectonics which focuses on the connection between plate tectonics and the different types of volcanoes. Provides questions for discussion and includes suggestions for extending the activity. (ML)

  8. Practical automatic Arabic license plate recognition system

    NASA Astrophysics Data System (ADS)

    Mohammad, Khader; Agaian, Sos; Saleh, Hani

    2011-02-01

    Since 1970's, the need of an automatic license plate recognition system, sometimes referred as Automatic License Plate Recognition system, has been increasing. A license plate recognition system is an automatic system that is able to recognize a license plate number, extracted from image sensors. In specific, Automatic License Plate Recognition systems are being used in conjunction with various transportation systems in application areas such as law enforcement (e.g. speed limit enforcement) and commercial usages such as parking enforcement and automatic toll payment private and public entrances, border control, theft and vandalism control. Vehicle license plate recognition has been intensively studied in many countries. Due to the different types of license plates being used, the requirement of an automatic license plate recognition system is different for each country. [License plate detection using cluster run length smoothing algorithm ].Generally, an automatic license plate localization and recognition system is made up of three modules; license plate localization, character segmentation and optical character recognition modules. This paper presents an Arabic license plate recognition system that is insensitive to character size, font, shape and orientation with extremely high accuracy rate. The proposed system is based on a combination of enhancement, license plate localization, morphological processing, and feature vector extraction using the Haar transform. The performance of the system is fast due to classification of alphabet and numerals based on the license plate organization. Experimental results for license plates of two different Arab countries show an average of 99 % successful license plate localization and recognition in a total of more than 20 different images captured from a complex outdoor environment. The results run times takes less time compared to conventional and many states of art methods.

  9. Electrically induced mechanical precompression of ferroelectric plates

    DOEpatents

    Chen, P.J.

    1987-03-02

    A method of electrically inducing mechanical precompression of ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion. 2 figs.

  10. Electrically induced mechanical precompression of ferroelectric plates

    DOEpatents

    Chen, Peter J.

    1987-01-01

    A method of electrically inducing mechanical precompression of a ferroelectric plate covered with electrodes utilizes the change in strains of the plate as functions of applied electric field. A first field polarizes and laterally shrinks the entire plate. An outer portion of the electrodes are removed, and an opposite field partially depolarizes and expands the central portion of the plate against the shrunk outer portion.

  11. Axisymmetric vibrations of layered tapered plates

    NASA Astrophysics Data System (ADS)

    Navaneethakrishnan, P. V.; Chandrasekaran, K.; Ravisrinivas, N.

    1992-12-01

    The study of Navaneethakrishnan and Chandrasekaran (1989) on axisymmetric free vibrations of layered annular plates is extended to the vibrations of layered annular plates whose thickness can vary as the radial distance from the arbitrary concentric circle. Numerical results are presented, showing the relationship between the circular frequency of the plate vibration and the ratio between the inner and the outer radii of the plate.

  12. Electrochemical Assay of Gold-Plating Solutions

    NASA Technical Reports Server (NTRS)

    Chiodo, R.

    1982-01-01

    Gold content of plating solution is assayed by simple method that required only ordinary electrochemical laboratory equipment and materials. Technique involves electrodeposition of gold from solution onto electrode, the weight gain of which is measured. Suitable fast assay methods are economically and practically necessary in electronics and decorative-plating industries. If gold content in plating bath is too low, poor plating may result, with consequent economic loss to user.

  13. What was Earth's tectonic style before Plate Tectonics?

    NASA Astrophysics Data System (ADS)

    Rey, P. F.; Coltice, N.; Flament, N. E.

    2015-12-01

    In the Archean, deep mantle upwelling resulted in the formation of thick, buoyant, hot and therefore weak continental plates, as well as thicker oceanic crusts and plateaux that may have impeded and perhaps prevented modern style subduction. Continents were easy to deform and too weak to support high mountain belts and orogenic plateaux which characterize modern collisional orogens. Overall, it would be very surprising if Archean tectonics processes were similar than those observable today. Over the past decade, numerical experiments have shown that the style of subduction depends on i/ the degree of coupling between the upper and lower plate which controls whether subduction zones are double sided or single sided; ii/ the buoyancy of the subducting plate which controls whether subduction is spontaneous or requires a push and whether slabs retreat or not; iii/ the yield stress of the subducting plate which controls whether recurrent slab breakoff occurs or not. Studies focused on the behaviour of continental plates show that only minor thickening (tectonic or volcanic via the emplacement of continental flood basalts) is required for the crust to reach its solidus, which would have promoted the foundering of greenstone covers into the crust (sagduction). In a convergence setting, weak continents would have deformed easily and convergence mainly accommodated by lateral expulsion and lateral flow under a regional transcurrent tectonic regime. Numerical experiments suggest that thick and buoyant continents would have imparted significant horizontal stresses on adjacent oceanic plates, the slow spreading of thick and buoyant continents leading to the initiation of subduction. Provided that continental lithospheric mantle could spontaneously subduct, numerical experiments suggest that in a convergent setting accretionary orogeny rather than continental collision was a dominant tectonic style with implications for crustal growth and differentiation.

  14. Electroless metal plating of plastics

    DOEpatents

    Krause, Lawrence J.

    1984-01-01

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  15. Electroless metal plating of plastics

    DOEpatents

    Krause, Lawrence J.

    1986-01-01

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  16. Electroless metal plating of plastics

    DOEpatents

    Krause, L.J.

    1982-09-20

    Process for plating main group metals on aromatic polymers is carried out by the use of a nonaqueous solution of a salt of an alkali metal in a positive valence state and a main group metal in a negative valence state with contact between the solution and polymer providing a redox reaction causing the deposition of the main group metal and the reduction of the polymer. Products from the process exhibit useful decorative and electrical properties.

  17. Ion plated electronic tube device

    DOEpatents

    Meek, T.T.

    1983-10-18

    An electronic tube and associated circuitry which is produced by ion plating techniques. The process is carried out in an automated process whereby both active and passive devices are produced at very low cost. The circuitry is extremely reliable and is capable of functioning in both high radiation and high temperature environments. The size of the electronic tubes produced are more than an order of magnitude smaller than conventional electronic tubes.

  18. PRETREATING URANIUM FOR METAL PLATING

    DOEpatents

    Wehrmann, R.F.

    1961-05-01

    A process is given for anodically treating the surface of uranium articles, prior to metal plating. The metal is electrolyzed in an aqueous solution of about 10% polycarboxylic acid, preferably oxalic acid, from 1 to 5% by weight of glycerine and from 1 to 5% by weight of hydrochloric acid at from 20 to 75 deg C for from 30 seconds to 15 minutes. A current density of from 60 to 100 amperes per square foot is used.

  19. 3D Structure of collision in the Central Alps: lower-plate or upper-plate indentation?

    NASA Astrophysics Data System (ADS)

    Rosenberg, Claudio; Kissling, Eduard

    2013-04-01

    Combining surface geological information with P-wave tomography we constructed three orogen-scale cross sections in the western, central, and eastern parts of the Central Alps. These sections show some very significant differences in the way collisional shortening (inferred to be post-30 Ma) is accommodated. In the eastern (Engadine) section we estimate 98 km of shortening, out of which 87 km are accommodated in the upper plate, south of the Insubric Line. In the western (Simplon) section, we estimate a total of 82-92 km of shortening, 65-75 of which are accommodated north of the Insubric Line, within the wedge of accreted lower crustal material. In the central (Bergell) section we estimate 97 km of shortening almost equally partitioned between upper, Adriatic plate, and the wedge of accreted lower crustal material. The lower crust of the Adriatic plate forms a wedge that reaches a maximum N-S extension of approximately 60 km in the Engadine section, progressively decreasing westward and completely disappearing along the Simplon section where the Ivrea body forms the northern limit of Adria. This difference of 60km in the N-S extension of the lower crust corresponds to the difference of shortening of the middle and upper crust, between Engadine and Simplon sections, suggesting that formation of a lower crustal wedge in the Adriatic plate is a direct consequence of a strong intraplate decoupling, limiting shortening to the middle and upper parts of the crust. Whereas the Simplon section shows a classical example of upper plate indentation into a collisional wedge of accreted lower plate material, the Engadine section is a good example of lower plate indentation into an intensely deforming upper plate. The causes for this dramatic along-strike change of tectonic style within a segment of the orogen less than 200 km long, are probably due to the heterogeneous rheology of the lithosphere. The Ivrea body in the Simplon section increases the strength of the Adriatic

  20. Episodic plate tectonics on Venus

    NASA Technical Reports Server (NTRS)

    Turcotte, Donald

    1992-01-01

    Studies of impact craters on Venus from the Magellan images have placed important constraints on surface volcanism. Some 840 impact craters have been identified with diameters ranging from 2 to 280 km. Correlations of this impact flux with craters on the Moon, Earth, and Mars indicate a mean surface age of 0.5 +/- 0.3 Ga. Another important observation is that 52 percent of the craters are slightly fractured and only 4.5 percent are embayed by lava flows. These observations led researchers to hypothesize that a pervasive resurfacing event occurred about 500 m.y. ago and that relatively little surface volcanism has occurred since. Other researchers have pointed out that a global resurfacing event that ceased about 500 MYBP is consistent with the results given by a recent study. These authors carried out a series of numerical calculations of mantle convection in Venus yielding thermal evolution results. Their model considered crustal recycling and gave rapid planetary cooling. They, in fact, suggested that prior to 500 MYBP plate tectonics was active in Venus and since 500 MYBP the lithosphere has stabilized and only hot-spot volcanism has reached the surface. We propose an alternative hypothesis for the inferred cessation of surface volcanism on Venus. We hypothesize that plate tectonics on Venus is episodic. Periods of rapid plate tectonics result in high rates of subduction that cool the interior resulting in more sluggish mantle convection.

  1. Volcano spacing and plate rigidity

    SciTech Connect

    Brink, U. )

    1991-04-01

    In-plane stresses, which accompany the flexural deformation of the lithosphere under the load adjacent volcanoes, may govern the spacing of volcanoes in hotspot provinces. Specifically, compressive stresses in the vicinity of a volcano prevent new upwelling in this area, forcing a new volcano to develop at a minimum distance that is equal to the distance in which the radial stresses change from compressional to tensile (the inflection point). If a volcano is modeled as a point load on a thin elastic plate, then the distance to the inflection point is proportional to the thickness of the plate to the power of 3/4. Compilation of volcano spacing in seven volcanic groups in East Africa and seven volcanic groups of oceanic hotspots shows significant correlation with the elastic thickness of the plate and matches the calculated distance to the inflection point. In contrast, volcano spacing in island arcs and over subduction zones is fairly uniform and is much larger than predicted by the distance to the inflection point, reflecting differences in the geometry of the source and the upwelling areas.

  2. MTR plates modeling with MAIA

    SciTech Connect

    Marelle, V.; Dubois, S.; Ripert, M.; Noirot, J.

    2008-07-15

    MAIA is a thermo-mechanical code dedicated to the modeling of MTR fuel plates. The main physical phenomena modeled in the code are the cladding oxidation, the interaction between fuel and Al-matrix, the swelling due to fission products and the Al/fuel particles interaction. The creeping of the plate can be modeled in the mechanical calculation. MAIA has been validated on U-Mo dispersion fuel experiments such as IRIS 1 and 2 and FUTURE. The results are in rather good agreement with post-irradiation examinations. MAIA can also be used to calculate in-pile behavior of U{sub 3}Si{sub 2} plates as in the SHARE experiment irradiated in the SCK/Mol BR2 reactor. The main outputs given by MAIA throughout the irradiation are temperatures, cladding oxidation thickness, interaction thickness, volume fraction of meat constituents, swelling, displacements, strains and stresses. MAIA is originally a two-dimensional code but a three-dimensional version is currently under development. (author)

  3. Plating of proximal humeral fractures.

    PubMed

    Martetschläger, Frank; Siebenlist, Sebastian; Weier, Michael; Sandmann, Gunther; Ahrens, Philipp; Braun, Karl; Elser, Florian; Stöckle, Ulrich; Freude, Thomas

    2012-11-01

    The optimal treatment for proximal humeral fractures is controversial. Few data exist concerning the influence of the surgical approach on the outcome. The purpose of this study was to evaluate the clinical and radiological outcomes of proximal humeral fractures treated with locking plate fixation through a deltopectoral vs an anterolateral deltoid-splitting approach. Of 86 patients who met the inclusion criteria, 70 were available for follow-up examination. Thirty-three patients were treated through a deltopectoral approach and 37 through an anterolateral deltoid-splitting approach. In all cases, open reduction and internal fixation with a PHILOS locking plate (Synthes, Umkirch, Germany) was performed. Clinical follow-up included evaluation of pain, shoulder mobility, and strength. Constant score and Disabilities of the Arm, Shoulder and Hand (DASH) score were assessed. A clinical neurological examination of the axillary nerve was also performed. Consolidation, reduction, and appearance of head necrosis were evaluated radiographically. After a mean follow-up of 33 months, Constant scores, DASH scores, and American Shoulder and Elbow Surgeons scores showed no significant differences between the groups. Clinical neurologic examination of the axillary nerve revealed no obvious damage to the nerve in either group. Deltopectoral and anterolateral detoid-splitting approaches for plate fixation of proximal humeral fractures are safe and provide similar clinical outcomes. The results of this study suggest that the approach can be chosen according to surgeon preference.

  4. 46 CFR 169.665 - Name plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Name plates. 169.665 Section 169.665 Shipping COAST... Gross Tons § 169.665 Name plates. Each generator, motor and other major item f power equipment must be provided with a name plate indicating the manufacturer's name, its rating in volts and amperes or in...

  5. 46 CFR 169.665 - Name plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Name plates. 169.665 Section 169.665 Shipping COAST... Gross Tons § 169.665 Name plates. Each generator, motor and other major item f power equipment must be provided with a name plate indicating the manufacturer's name, its rating in volts and amperes or in...

  6. Moving Divertor Plates in a Tokamak

    SciTech Connect

    S.J. Zweben, H. Zhang

    2009-02-12

    Moving divertor plates could help solve some of the problems of the tokamak divertor through mechanical ingenuity rather than plasma physics. These plates would be passively heated on each pass through the tokamak and cooled and reprocessed outside the tokamak. There are many design options using varying plate shapes, orientations, motions, coatings, and compositions.

  7. Apparatus and method for controlling plating uniformity

    DOEpatents

    Hachman Jr., John T.; Kelly, James J.; West, Alan C.

    2004-10-12

    The use of an insulating shield for improving the current distribution in an electrochemical plating bath is disclosed. Numerical analysis is used to evaluate the influence of shield shape and position on plating uniformity. Simulation results are compared to experimental data for nickel deposition from a nickel--sulfamate bath. The shield is shown to improve the average current density at a plating surface.

  8. FASTENER FOR AN ASSEMBLY OF PLATES

    DOEpatents

    Groh, E.F.

    1963-08-20

    A fastener is provided for a spaced-apart parallel plate fuel assembly. The fastener, attached by screws to a key that passes through the edges of the assembled plate, serves as a retainer for the outermost plate as well as a bidirectional spacer for separating the fuel assembly from two neighboring fuel assemblies. (AEC)

  9. Recent plate motions and crustal deformation

    SciTech Connect

    Lisowski, M. )

    1991-01-01

    Reports by U.S. workers on geodetic measurements of recent plate motions or crustal deformation published in 1987-1990 are reviewed. The review begins with global plate motions, proceeds through plate boundaries in California, Alaska, and the Pacific Northwest, and finishes with volcanic phenomena, monument stability and longevity, and GPS relative position measurements. 184 refs.

  10. 21 CFR 872.4760 - Bone plate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Bone plate. 872.4760 Section 872.4760 Food and... DENTAL DEVICES Surgical Devices § 872.4760 Bone plate. (a) Identification. A bone plate is a metal device intended to stabilize fractured bone structures in the oral cavity. The bone segments are attached to...

  11. 21 CFR 872.4760 - Bone plate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Bone plate. 872.4760 Section 872.4760 Food and... DENTAL DEVICES Surgical Devices § 872.4760 Bone plate. (a) Identification. A bone plate is a metal device intended to stabilize fractured bone structures in the oral cavity. The bone segments are attached to...

  12. 21 CFR 872.4760 - Bone plate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bone plate. 872.4760 Section 872.4760 Food and... DENTAL DEVICES Surgical Devices § 872.4760 Bone plate. (a) Identification. A bone plate is a metal device intended to stabilize fractured bone structures in the oral cavity. The bone segments are attached to...

  13. 21 CFR 872.4760 - Bone plate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Bone plate. 872.4760 Section 872.4760 Food and... DENTAL DEVICES Surgical Devices § 872.4760 Bone plate. (a) Identification. A bone plate is a metal device intended to stabilize fractured bone structures in the oral cavity. The bone segments are attached to...

  14. 21 CFR 872.4760 - Bone plate.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Bone plate. 872.4760 Section 872.4760 Food and... DENTAL DEVICES Surgical Devices § 872.4760 Bone plate. (a) Identification. A bone plate is a metal device intended to stabilize fractured bone structures in the oral cavity. The bone segments are attached to...

  15. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  16. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 5 2011-04-01 2011-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  17. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 5 2013-04-01 2013-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  18. 24 CFR 3280.5 - Data plate.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 5 2010-04-01 2010-04-01 false Data plate. 3280.5 Section 3280.5... MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS General § 3280.5 Data plate. Each manufactured home shall bear a data plate affixed in a permanent manner near the main electrical panel or other...

  19. Atomic layer deposited borosilicate glass microchannel plates for large area event counting detectors

    NASA Astrophysics Data System (ADS)

    Siegmund, O. H. W.; McPhate, J. B.; Tremsin, A. S.; Jelinsky, S. R.; Hemphill, R.; Frisch, H. J.; Elam, J.; Mane, A.; Lappd Collaboration

    2012-12-01

    Borosilicate glass micro-capillary array substrates with 20 μm and 40 μm pores have been deposited with resistive, and secondary electron emissive, layers by atomic layer deposition to produce functional microchannel plates. Device formats of 32.7 mm and 20 cm square have been fabricated and tested in analog and photon counting modes. The tests show amplification, imaging, background rate, pulse shape and lifetime characteristics that are comparable to standard glass microchannel plates. Large area microchannel plates of this type facilitate the construction of 20 cm format sealed tube sensors with strip-line readouts that are being developed for Cherenkov light detection. Complementary work has resulted in Na2KSb bialkali photocathodes with peak quantum efficiency of 25% being made on borosilicate glass. Additionally GaN (Mg) opaque photocathodes have been successfully made on borosilicate microchannel plates.

  20. Peridinialean dinoflagellate plate patterns, labels and homologies

    USGS Publications Warehouse

    Edwards, L.E.

    1990-01-01

    Tabulation patterns for peridinialean dinoflagellate thecae and cysts have been traditionally expressed using a plate labelling system described by C.A. Kofoid in the early 1900's. This system can obscure dinoflagellate plate homologies and has not always been strictly applied. The plate-labelling system presented here introduces new series labels but incorporates key features and ideas from the more recently proposed systems of G.L. Eaton and F.J.R. Taylor, as modified by W.R. Evitt. Plate-series recognition begins with the cingulum (C-series) and proceeds from the cingulum toward the apex for the three series of the epitheca/epicyst and proceeds from the cingulum toward the antapex for the two series of the hypotheca/hypocyst. The epithecal/epicystal model consists of eight plates that touch the anterior margin of the cingulum (E-series: plates E1-E7, ES), seven plates toward the apex that touch the E-series plates (M-series: R, M1-M6), and up to seven plates near the apex that do not touch E-series plates (D-series: Dp-Dv). The hypothecal/hypocystal model consists of eight plates that touch the posterior margin of the cingulum (H-series: H1-H6,HR,HS) and three plates toward the antapex (T1-T3). Epithecal/epicystal tabulation patterns come in both 8- and 7- models, corresponding to eight and seven plates, respectively, in the E-series. Hypothecal/hypocystal tabulation patterns also come in both 8- and 7-models, corresponding to eight and seven plates, respectively, in the H-series. By convention, the 7-model epitheca/epicyst has no plates E1 and M1; the 7-model hypotheca/hypocyst has no plate H6. Within an 8-model or 7-model, the system emphasizes plates that are presumed to be homologous by giving them identical labels. I introduce the adjectives "monothigmate", "dithigmate," and "trithigmate" to designate plates touching one, two, and three plates, respectively, of the adjacent series. The term "thigmation" applies to the analysis of plate contacts between

  1. Quantum levitation of a thin magnetodielectric plate on a metallic plate using the repulsive Casimir force

    NASA Astrophysics Data System (ADS)

    Inui, Norio

    2012-04-01

    Levitation of a thin magnetodielectric plate on a metallic plate by using the repulsive Casimir force is theoretically considered. If the permittivity of the metallic plate near zero frequency is expressed by a plasma model and the static permeability of the magnetodielectric plate is higher than its static permittivity, the Casimir force between the magnetodielectric plate and the metallic plate changes from attractive to repulsive as the separation between them increases. Furthermore, as the thickness of the magnetodielectric plate is decreased, the attractive component of the Casimir force decreases more than the repulsive one. This effect generates a larger repulsive Casimir force as compared with that between the plates having infinite thickness. Combined with the effect of decreasing the weight of the plate, this might enable a thin plate to levitate in vacuum. The height of quantum levitation is evaluated for a combination of yttrium iron garnet and gold.

  2. Steady state response of unsymmetrically laminated plates

    SciTech Connect

    Hosokawa, Kenji; Kawashima, Katsuya; Sakata, Toshiyuki

    1995-11-01

    A numerical approach for analyzing the forced vibration problem of a symmetrically laminated FRP (fiber reinforced plastic) composite plate was proposed by the authors. In the present paper, this approach is modified for application to an unsymmetrically laminated FRP composite plate. Numerical calculations are carried out for the clamped antisymmetrically laminated rectangular and elliptical plates which are a kind of unsymmetrically laminated plate. Then,, the effects of the lamina material and the fiber orientation angle on the steady state response are discussed. Furthermore, it is investigated that what structural damping factor is most influenced on the steady state response of an antisymmetrically laminated plate.

  3. Wheelspace windage cover plate for turbine

    DOEpatents

    Lathrop, Norman Douglas

    2002-01-01

    Windage cover plates are secured between the wheels and spacer of a turbine rotor to prevent hot flow path gas ingestion into the wheelspace cavities. Each cover plate includes a linear, axially extending body curved circumferentially with a radially outwardly directed wall at one axial end. The wall defines a axially opening recess for receiving a dovetail lug. The cover plate includes an axially extending tongue received in a circumferential groove of the spacer. The cover plate is secured with the tongue in the groove and dovetail lug in the recess. Lap joints between circumferentially adjacent cover plates are provided.

  4. Separator plate for a fuel cell

    DOEpatents

    Petri, R.J.; Meek, J.; Bachta, R.P.; Marianowski, L.G.

    1996-04-02

    A separator plate is described for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced. 9 figs.

  5. Separator plate for a fuel cell

    DOEpatents

    Petri, Randy J.; Meek, John; Bachta, Robert P.; Marianowski, Leonard G.

    1996-01-01

    A separator plate for a fuel cell comprising an anode current collector, a cathode current collector and a main plate, the main plate disposed between the anode current collector and the cathode current collector. The anode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the anode side of the separator plate and the cathode current collector forms a flattened peripheral wet seal structure and manifold wet seal structure on the cathode side of the separator plate. In this manner, the number of components required to manufacture and assemble a fuel cell stack is reduced.

  6. Mechanism for Corrosion Prevention by a Mechanical Plating of Uniform Zinc-Iron Alloy

    NASA Astrophysics Data System (ADS)

    Kasai, Naoya; Kaku, Yoshihiko; Okazaki, Shinji; Hirai, Kuninori

    2016-09-01

    In situ electrochemical monitoring with a three-electrode cell was applied to investigate the anti-corrosion properties of a mechanical zinc-iron alloy plating. Several electron probe microanalyses were also conducted to identify the chemical elements in the plating. The results indicated the formation of a Zn-Fe intermetallic compound, which allowed a mechanism for corrosion prevention to be proposed. In the proposed mechanism, Zn(OH)2 plays a significant role in the corrosion prevention of steel alloys.

  7. Improved oxides for production of lead/acid battery plates

    NASA Astrophysics Data System (ADS)

    Boden, D. P.

    For many years, the plates of lead/acid batteries have been produced from leady oxide, a mixture of finely divided lead (`free-lead') and lead monoxide. Although this material is generally satisfactory, it suffers from the disadvantages that it is variable in composition and requires complicated and lengthy processing after pasting to remove the residual free-lead. Plates made from leady oxide also require cycling before they achieve their full performance, and this can result in either depressed initial capacity or additional processing cost. There is a growing trend towards the use of pure lead monoxide ( β-PbO) for the production of positive plates. This material is particularly valuable in valve-regulated batteries where cell-to-cell uniformity is essential for proper control of battery performance. It also reduces processing cost since it does not require time-consuming curing to remove free-lead. Red lead (Pb 3O 4) is also being more widely used in industrial batteries since it reduces formation time, and improves initial and high-rate performance. The methods of production of leady oxide, β-PbO and red lead are briefly reviewed and the characteristics of battery-grade materials are described. Particular emphasis is placed on optimum particle-size distribution, and how this can affect the battery performance. The benefits in processing and performance are described together with information on how pure litharge and red lead are used in battery plates.

  8. Absolute Plate Velocities from Seismic Anisotropy

    NASA Astrophysics Data System (ADS)

    Kreemer, Corné; Zheng, Lin; Gordon, Richard

    2015-04-01

    The orientation of seismic anisotropy inferred beneath plate interiors may provide a means to estimate the motions of the plate relative to the sub-asthenospheric mantle. Here we analyze two global sets of shear-wave splitting data, that of Kreemer [2009] and an updated and expanded data set, to estimate plate motions and to better understand the dispersion of the data, correlations in the errors, and their relation to plate speed. We also explore the effect of using geologically current plate velocities (i.e., the MORVEL set of angular velocities [DeMets et al. 2010]) compared with geodetically current plate velocities (i.e., the GSRM v1.2 angular velocities [Kreemer et al. 2014]). We demonstrate that the errors in plate motion azimuths inferred from shear-wave splitting beneath any one tectonic plate are correlated with the errors of other azimuths from the same plate. To account for these correlations, we adopt a two-tier analysis: First, find the pole of rotation and confidence limits for each plate individually. Second, solve for the best fit to these poles while constraining relative plate angular velocities to consistency with the MORVEL relative plate angular velocities. The SKS-MORVEL absolute plate angular velocities (based on the Kreemer [2009] data set) are determined from the poles from eight plates weighted proportionally to the root-mean-square velocity of each plate. SKS-MORVEL indicates that eight plates (Amur, Antarctica, Caribbean, Eurasia, Lwandle, Somalia, Sundaland, and Yangtze) have angular velocities that differ insignificantly from zero. The net rotation of the lithosphere is 0.25±0.11° Ma-1 (95% confidence limits) right-handed about 57.1°S, 68.6°E. The within-plate dispersion of seismic anisotropy for oceanic lithosphere (σ=19.2° ) differs insignificantly from that for continental lithosphere (σ=21.6° ). The between-plate dispersion, however, is significantly smaller for oceanic lithosphere (σ=7.4° ) than for continental

  9. Photostimulated luminescence properties of neutron image plates

    NASA Astrophysics Data System (ADS)

    Popov, A. I.; Zimmermann, J.; McIntyre, G. J.; Wilkinson, C.

    2016-09-01

    The luminescence properties of two commercial neutron-sensitive image-plates based on Gd2O3-doped BaFBr:Eu2+ storage phosphors are examined. These are white Fuji plates and blue Fuji plates (BAS-ND) with Gd2O3 content by weight of 34% and 50%, respectively. Both plates show two maxima in the photostimulation spectrum near 500 nm and 600 nm, with the ratio of the peak responses (I600 nm/I500 nm) 1.39 and 0.53 for the white and blue plates respectively. The optimum wavelengths for photostimulation for the two phosphors are therefore different. The response of the blue plate is only 25% that of the white plate, if each is stimulated at its optimum wavelength.

  10. Astronomical Photographic Plate Collections: Treasure or Trash?

    NASA Astrophysics Data System (ADS)

    Osborn, W. H.; Castelaz, M. W.; Cline, J. D.

    2005-12-01

    Our efforts over the past three years to establish a national archive for astronomical plates will be described. This work has led to the following major conclusions regarding the preservation of astronomical photographic plates: (1) a significant number of observatories, as well as retiring astronomers, wish to dispose of the plates they hold; (2) most astronomers feel direct and spectroscopic plates of potential scientific value should be preserved; (3) there is little interest in providing support for preservation efforts on a broad scale. We offer that the astronomical community must quickly decide to preserve plate collections or they will soon be lost, either consciously discarded or through benign neglect. If a systematic effort to preserve these archival data is indeed to be made, priorities need to be established. Not only is archiving (and eventually digitizing) all existing plates impracticable, many plates have little or no potential value. We will present our ideas on priorities and seek the input of the community.

  11. Removal of between-run variation in a multi-plate qPCR experiment.

    PubMed

    Ruijter, Jan M; Ruiz Villalba, Adrián; Hellemans, Jan; Untergasser, Andreas; van den Hoff, Maurice J B

    2015-09-01

    Quantitative PCR (qPCR) is the method of choice in gene expression analysis. However, the number of groups or treatments, target genes and technical replicates quickly exceeds the capacity of a single run on a qPCR machine and the measurements have to be spread over more than 1 plate. Such multi-plate measurements often show similar proportional differences between experimental conditions, but different absolute values, even though the measurements were technically carried out with identical procedures. Removal of this between-plate variation will enhance the power of the statistical analysis on the resulting data. Inclusion and application of calibrator samples, with replicate measurements distributed over the plates, assumes a multiplicative difference between plates. However, random and technical errors in these calibrators will propagate to all samples on the plate. To avoid this effect, the systematic bias between plates can be removed with a correction factor based on all overlapping technical and biological replicates between plates. This approach removes the requirement for all calibrator samples to be measured successfully on every plate. This paper extends an already published factor correction method to the use in multi-plate qPCR experiments. The between-run correction factor is derived from the target quantities which are calculated from the quantification threshold, PCR efficiency and observed C q value. To enable further statistical analysis in existing qPCR software packages, an efficiency-corrected C q value is reported, based on the corrected target quantity and a PCR efficiency per target. The latter is calculated as the mean of the PCR efficiencies taking the number of reactions per amplicon per plate into account. Export to the RDML format completes an RDML-supported analysis pipeline of qPCR data ranging from raw fluorescence data, amplification curve analysis and application of reference genes to statistical analysis. PMID:27077038

  12. Early breakup of Gondwana: constraints from global plate motion models

    NASA Astrophysics Data System (ADS)

    Seton, Maria; Zahirovic, Sabin; Williams, Simon; Whittaker, Joanne; Gibbons, Ana; Muller, Dietmar; Brune, Sascha; Heine, Christian

    2015-04-01

    Supercontinent break-up and amalgamation is a fundamental Earth cycle, contributing to long-term sea-level fluctuations, species diversity and extinction events, long-term greenhouse-icehouse cycles and changes in the long-wavelength density structure of the mantle. The most recent and best-constrained example involves the fragmentation of Gondwana, starting with rifting between Africa/Madagascar and Antarctica in the Early Jurassic and ending with the separation of the Lord Howe microcontinental blocks east of Australia in the Late Cretaceous. Although the first order configuration of Gondwana within modern reconstructions appears similar to that first proposed by Wegener a century ago, recent studies utilising a wealth of new geophysical and geological data provide a much more detailed picture of relative plate motions both during rifting and subsequent seafloor spreading. We present our latest global plate motion model that includes extensive, new regional analyses. These include: South Atlantic rifting, which started at 150 Ma and propagated into cratonic Africa by 145 Ma (Heine et al., 2013); rifting and early seafloor spreading between Australia, India and Antarctica, which reconciles the fit between Broken Ridge-Kergulean Plateau and the eastern Tasman region (Whittaker et al., 2013); rifting of continental material from northeastern Gondwana and its accretion onto Eurasia and SE Asia including a new model of microcontinent formation and early seafloor spreading in the eastern Indian Ocean (Gibbons et al., 2012; 2013; in review; Williams et al., 2013; Zahirovic et al., 2014); and a new model for the isolation of Zealandia east of Australia, with rifting initiating at 100 Ma until the start of seafloor spreading in the Tasman Sea at ~85 Ma (Williams et al., in prep). Using these reconstructions within the open-source GPlates software, accompanied by a set of evolving plates and plate boundaries, we can explore the factors that govern the behavior of plate

  13. Quantification of biofilm in microtiter plates: overview of testing conditions and practical recommendations for assessment of biofilm production by staphylococci.

    PubMed

    Stepanović, Srdjan; Vuković, Dragana; Hola, Veronika; Di Bonaventura, Giovanni; Djukić, Slobodanka; Cirković, Ivana; Ruzicka, Filip

    2007-08-01

    The details of all steps involved in the quantification of biofilm formation in microtiter plates are described. The presented protocol incorporates information on assessment of biofilm production by staphylococci, gained both by direct experience as well as by analysis of methods for assaying biofilm production. The obtained results should simplify quantification of biofilm formation in microtiter plates, and make it more reliable and comparable among different laboratories.

  14. Assessment of carbon fibre composite fracture fixation plate using finite element analysis.

    PubMed

    Saidpour, Seyed H

    2006-07-01

    In the internal fixation of fractured bone by means of bone-plates fastened to the bone on its tensile surface, an on-going concern has been the excessive stress shielding of the bone by the excessively-stiff stainless-steel plate. The compressive stress shielding at the fracture-interface immediately after fracture-fixation delays callus formation and bone healing. Likewise, the tensile stress shielding in the layer of bone underneath the plate can cause osteoporosis and decrease in tensile strength of this layer. In this study a novel forearm internal fracture fixation plate made from short carbon fibre reinforced plastic (CFRP) was used in an attempt to address the problem. Accordingly, it has been possible to analyse the stress distribution in the composite plates using finite-element modelling. A three-dimensional, quarter-symmetric finite element model was generated for the plate system. The stress state in the underlying bone was examined for several loading conditions. Based on the analytical results the composite plate system is likely to reduce stress-shielding effects at the fracture site when subjected to bending and torsional loads. The design of the plate was further optimised by reducing the width around the innermost holes.

  15. Tectonic speed limits from plate kinematic reconstructions

    NASA Astrophysics Data System (ADS)

    Zahirovic, Sabin; Müller, R. Dietmar; Seton, Maria; Flament, Nicolas

    2015-05-01

    The motion of plates and continents on the planet's surface are a manifestation of long-term mantle convection and plate tectonics. Present-day plate velocities provide a snapshot of this ongoing process, and have been used to infer controlling factors on the speeds of plates and continents. However, present-day velocities do not capture plate behaviour over geologically representative periods of time. To address this shortcoming, we use a plate tectonic reconstruction approach to extract time-dependent plate velocities and geometries from which root mean square (RMS) velocities are computed, resulting in a median RMS plate speed of ∼ 4 cm /yr over 200 Myr. Linking tectonothermal ages of continental lithosphere to the RMS plate velocity analysis, we find that the increasing portions of plate area composed of continental and/or cratonic lithosphere significantly reduces plate speeds. Plates with any cratonic portion have a median RMS velocity of ∼ 5.8 cm /yr, while plates with more than 25% of cratonic area have a median RMS speed of ∼ 2.8 cm /yr. The fastest plates (∼ 8.5 cm /yr RMS speed) have little continental fraction and tend to be bounded by subduction zones, while the slowest plates (∼ 2.6- 2.8 cm /yr RMS speed) have large continental fractions and usually have little to no subducting part of plate perimeter. More generally, oceanic plates tend to move 2-3 times faster than continental plates, consistent with predictions of numerical models of mantle convection. The slower motion of continental plates is compatible with deep keels impinging on asthenospheric flow and increasing shear traction, thus anchoring the plate in the more viscous mantle transition zone. We also find that short-lived (up to ∼ 10 Myr) rapid accelerations of Africa (∼100 and 65 Ma), North America (∼100 and 55 Ma) and India (∼ 130 , 80 and 65 Ma) appear to be correlated with plume head arrivals as recorded by large igneous province (LIPs) emplacement. By evaluating

  16. 96-well microtiter plates for biofouling simulation in biomedical settings.

    PubMed

    Gomes, L C; Moreira, J M R; Teodósio, J S; Araújo, J D P; Miranda, J M; Simões, M; Melo, L F; Mergulhão, F J

    2014-01-01

    Microtiter plates with 96 wells are routinely used in biofilm research mainly because they enable high-throughput assays. These platforms are used in a variety of conditions ranging from static to dynamic operation using different shaking frequencies and orbital diameters. The main goals of this work were to assess the influence of nutrient concentration and flow conditions on biofilm formation by Escherichia coli in microtiter plates and to define the operational conditions to be used in order to simulate relevant biomedical scenarios. Assays were performed in static mode and in incubators with distinct orbital diameters using different concentrations of glucose, peptone and yeast extract. Computational fluid dynamics (CFD) was used to simulate the flow inside the wells for shaking frequencies ranging from 50 to 200 rpm and orbital diameters from 25 to 100 mm. Higher glucose concentrations enhanced adhesion of E. coli in the first 24 h, but variation in peptone and yeast extract concentration had no significant impact on biofilm formation. Numerical simulations indicate that 96-well microtiter plates can be used to simulate a variety of biomedical scenarios if the operating conditions are carefully set.

  17. Ultrathin plasmonic chiral phase plate.

    PubMed

    Gorodetski, Yuri; Genet, Cyriaque; Ebbesen, Thomas W

    2016-09-15

    A thin free-standing gold membrane with complex plasmonic structures engraved on both sides is shown to perform as an ultrathin phase plate. Specifically, we demonstrate the generation of a far-field vortex beam propagating at a desired angle. The angular momentum of the beam is generated by the groove helicity, together with the geometric phase arising from a plasmonic spin-orbit interaction. The radial chirp of the back-side structure is used to modify the emission angle via a specific momentum matching condition. PMID:27628405

  18. Turbulent flows near flat plates

    NASA Astrophysics Data System (ADS)

    Kambe, R.; Imamura, T.; Doi, M.

    1980-08-01

    The method to study the effect of the plate moving in the homogeneous or isotropic turbulence is presented. The crucial point of this method is to solve the Orr-Sommerfeld like equation, which is satisfied by the kernel of the Wiener-Hermite expansion of the velocity field, under the inhomogeneous boundary condition. In the special case of constant mean flow, our method gives the same result as that of Hunt and Graham and succeeds in explaining the experimental results of Thomas and Hancock. The method is also applied to the case of nonuniform mean flow, where the shear effect comes up.

  19. Adherent protective coatings plated on magnesium-lithium alloy

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Zinc is plated on a magnesium-lithium alloy by using a modification of the standard zinc-plate immersion bath. Further protection is given the alloy by applying a light plating of copper on the zinc plating. Other metals are plated on the copper by using conventional plating baths.

  20. A Refined Shear Deformation Plate Theory

    NASA Astrophysics Data System (ADS)

    Liu, Yucheng

    2011-04-01

    An improved higher-order shear deformation theory of plates is presented in this paper. The theory is developed from the transverse shear deformation theory presented by Ambartsumian [11]. The present plate theory contains kinematics of higher-order displacement field of plates, a system of higher-order differential equilibrium equations in terms of the three generalized displacements of bending plates, and a system of boundary conditions at each edge of plate boundaries. The present shear deformation theory of plates is validated by applying it to solve torsional plates and simply supported plates. The obtained solutions using the present theory are compared with the solutions of other shear-deformation theories. A good agreement is achieved through these comparisons and the advantages of the present theory are clearly verified. The shear deformation plate theory presented here can be applied to the analysis of laminated composite plates to better predict their dynamic and static behaviors. The proposed theory should also be supplemented to the theory of finite element analysis for developing new shell elements.

  1. Petrologic implications of plate tectonics.

    PubMed

    Yoder, H S

    1971-07-30

    Petrologists can make significant contributions to the plate tectonic concept. Fixing the stability fields of the principal rock types involved will provide the limits of pressure and temperature of the various environments. Experimental determination of the partition coefficients of the trace elements will be helpful. Studies of the partial melting behavior of possible parental materials in the absence and presence of water, especially the undersaturated region, will contribute to the understanding of magma production. Experimental observations on the rheological properties of the peridotites below and just above the solidus will lead to a better evaluation of the convective mechanism. Measurement of the fundamental properties of rocks, such as the density of solids and liquids at high pressures and temperatures, would contribute to understanding the concepts of diapiric rise, magma segregation, and the low-velocity zone. Broader rock sampling of the oceanic areas of all environments will do much to define the petrologic provinces. The field petrologist specializing in the Paleozoic regions and Precambrian shields can contribute by examining those regions for old plate boundaries and devising new criteria for their recognition. PMID:17770454

  2. Petrologic implications of plate tectonics.

    PubMed

    Yoder, H S

    1971-07-30

    Petrologists can make significant contributions to the plate tectonic concept. Fixing the stability fields of the principal rock types involved will provide the limits of pressure and temperature of the various environments. Experimental determination of the partition coefficients of the trace elements will be helpful. Studies of the partial melting behavior of possible parental materials in the absence and presence of water, especially the undersaturated region, will contribute to the understanding of magma production. Experimental observations on the rheological properties of the peridotites below and just above the solidus will lead to a better evaluation of the convective mechanism. Measurement of the fundamental properties of rocks, such as the density of solids and liquids at high pressures and temperatures, would contribute to understanding the concepts of diapiric rise, magma segregation, and the low-velocity zone. Broader rock sampling of the oceanic areas of all environments will do much to define the petrologic provinces. The field petrologist specializing in the Paleozoic regions and Precambrian shields can contribute by examining those regions for old plate boundaries and devising new criteria for their recognition.

  3. Wide-Field Plate Database

    NASA Astrophysics Data System (ADS)

    Tsvetkov, M. K.; Stavrev, K. Y.; Tsvetkova, K. P.; Semkov, E. H.; Mutatov, A. S.

    The Wide-Field Plate Database (WFPDB) and the possibilities for its application as a research tool in observational astronomy are presented. Currently the WFPDB comprises the descriptive data for 400 000 archival wide field photographic plates obtained with 77 instruments, from a total of 1 850 000 photographs stored in 269 astronomical archives all over the world since the end of last century. The WFPDB is already accessible for the astronomical community, now only in batch mode through user requests sent by e-mail. We are working on on-line interactive access to the data via INTERNET from Sofia and parallel from the Centre de Donnees Astronomiques de Strasbourg. (Initial information can be found on World Wide Web homepage URL http://www.wfpa.acad.bg.) The WFPDB may be useful in studies of a variety of astronomical objects and phenomena, andespecially for long-term investigations of variable objects and for multi-wavelength research. We have analysed the data in the WFPDB in order to derive the overall characteristics of the totality of wide-field observations, such as the sky coverage, the distributions by observation time and date, by spectral band, and by object type. We have also examined the totality of wide-field observations from point of view of their quality, availability and digitisation. The usefulness of the WFPDB is demonstrated by the results of identification and investigation of the photometrical behaviour of optical analogues of gamma-ray bursts.

  4. Rapid and Sensitive Plate Method for Detection of Aspergillus fumigatus

    PubMed Central

    Bauters, T. G. M.; Nelis, H. J.

    2000-01-01

    The routine identification of Aspergillus fumigatus in clinical samples involves, apart from direct examination, the isolation of the organism on a plate followed by its microscopic characterization. This approach lacks sensitivity, specificity, and speed. A new procedure has been developed combining microcolony formation on a nylon membrane filter at 45°C with the detection of a specific 4-methylumbelliferyl-α-l-arabinopyranoside cleaving enzyme activity in digitonin permeabilized cells. The test takes approximately 14 h and has an efficiency of 98.2% and false-positive and -negative rates of 0 and 3.1%, respectively. When applied to 188 clinical samples taken from patients with proven or nonproven presence of Aspergillus species, a good agreement with the conventional plate-microscopy method was obtained. PMID:11015405

  5. Electroless plating of copper on surface-modified glass substrate

    NASA Astrophysics Data System (ADS)

    Su, Wei; Yao, Libei; Yang, Fang; Li, Peiyuan; Chen, Juan; Liang, Lifang

    2011-07-01

    This work focuses on developing a novel convenient method for electroless copper deposition on glass material. This method is relied on the formation of amino (NH2)-terminated film on the surface of glass substrate, by coating polyethylenimine (PEI) on glass matrix and using epichlorohydrin (ECH) as cross-linking agent. The introduced amino groups can effectively adsorb the palladium, the catalysts which could initiate the subsequent Cu electroless plating, onto the glass substrate surface. Finally, a copper film is formed on the palladium-activated glass substrate through copper electroless plating and the surface-coppered glass material is therefore acquired. X-ray diffraction (XRD), atomic force microscope (AFM), scanning electron microscopy (SEM) images combined with energy diffraction X-ray (EDX) analysis demonstrate the successful copper deposition on the surface of glass substrate.

  6. High-throughput quantitative real-time RT-PCR assay for determining expression profiles of types I and III interferon subtypes.

    PubMed

    Renn, Lynnsey A; Theisen, Terence C; Navarro, Maria B; Mane, Viraj P; Schramm, Lynnsie M; Kirschman, Kevin D; Fabozzi, Giulia; Hillyer, Philippa; Puig, Montserrat; Verthelyi, Daniela; Rabin, Ronald L

    2015-01-01

    Described in this report is a qRT-PCR assay for the analysis of seventeen human IFN subtypes in a 384-well plate format that incorporates highly specific locked nucleic acid (LNA) and molecular beacon (MB) probes, transcript standards, automated multichannel pipetting, and plate drying. Determining expression among the type I interferons (IFN), especially the twelve IFN-α subtypes, is limited by their shared sequence identity; likewise, the sequences of the type III IFN, especially IFN-λ2 and -λ3, are highly similar. This assay provides a reliable, reproducible, and relatively inexpensive means to analyze the expression of the seventeen interferon subtype transcripts.

  7. High-throughput measurements of biochemical responses using the plate::vision multimode 96 minilens array reader.

    PubMed

    Huang, Kuo-Sen; Mark, David; Gandenberger, Frank Ulrich

    2006-01-01

    The plate::vision is a high-throughput multimode reader capable of reading absorbance, fluorescence, fluorescence polarization, time-resolved fluorescence, and luminescence. Its performance has been shown to be quite comparable with other readers. When the reader is integrated into the plate::explorer, an ultrahigh-throughput screening system with event-driven software and parallel plate-handling devices, it becomes possible to run complicated assays with kinetic readouts in high-density microtiter plate formats for high-throughput screening. For the past 5 years, we have used the plate::vision and the plate::explorer to run screens and have generated more than 30 million data points. Their throughput, performance, and robustness have speeded up our drug discovery process greatly.

  8. The conditions for plate tectonics: what went wrong everywhere else

    NASA Astrophysics Data System (ADS)

    Jellinek, M.; O'Neill, C.; Lenardic, A.

    2005-12-01

    A necessary precursor for the onset of plate tectonics on a terrestrial planet is that the intrinsic system stresses, generally associated with buoyancy anomalies, are great enough to overcome the resistance of the lithosphere to deformation. On Earth, these stresses are generally associated with the subduction of oceanic lithosphere - leading to the notion that the plates drive themselves. On planets without existing plate tectonics, the most significant buoyancy anomalies are associated with the formation and sinking of cold downwelling 'thermals'. The question we address is under what conditions are stresses associated these cold thermals sufficient to initiate failure of the lithosphere? Lithospheric strength is a function of its friction coefficient and elastic thickness (or, equivalently, the depth to the brittle-ductile transition). Both and plate's yield strength, and convective stresses, depend critically on the size and thermal evolution of a planet. We use numerical simulations and scaling theory to identify conditions under which mantle convection generates lithospheric failure, for parameters appropriate to the terrestrial planets. While the Moon and Mercury are predicted to have always been in a stagnant lid regime, Earth is, predictably, in a 'failed-lid' regime. Venus and Io currently fall on the transition between the two regimes. This is consistent with an episodic-style of convection on Venus, and suggests a tectonic component of deformation on Io. Mars is in a stagnant lid regime now, and probably was for most its history; however, early Martian plate tectonics is plausible if the lithosphere was weakened by the presence of surface water during the first 500Myr of its history.

  9. Effect of plate roughness on the field near RPC plates

    NASA Astrophysics Data System (ADS)

    Jash, A.; Majumdar, N.; Mukhopadhyay, S.; Chattopadhyay, S.

    2016-06-01

    The inner surfaces of the electrodes encompassing the gas volume of a Resistive Plate Chamber (RPC) have been found to exhibit asperities with, grossly, three kind of features. The desired uniform electric field within the gas volume of RPC is expected to be affected due to the presence of these asperities, which will eventually affect the final response from the detector. In this work, an attempt has been made to model the highly complex roughness of the electrode surfaces and compute its effect on the electrostatic field within RPC gas chamber. The calculations have been performed numerically using Finite Element Method (FEM) and Boundary Element Method (BEM) and the two methods have been compared in this context.

  10. Axisymmetric vibration of circular plates and its analog in elliptical plates using characteristic orthogonal polynomials

    NASA Astrophysics Data System (ADS)

    Rajalingham, C.; Bhat, R. B.

    1993-02-01

    The axisymmetric vibration of circular plates and its analog in elliptic plates with clamped, simply supported and free boundary conditions are investigated using boundary characteristic orthogonal polynomials in the Rayleigh-Ritz method. Modified polar coordinates are employed to analyze the vibration of elliptical plates, with circular plates as a special case. Axisymmetric vibration of circular plates and its analog in elliptical plates with concentric nodal elipses require only one-dimensional shape functions in the Rayleigh-Ritz method. The first six natural frequencies and the parameters associated with nodal ellipses are tabulated.

  11. Performance of Small Pore Microchannel Plates

    NASA Technical Reports Server (NTRS)

    Siegmund, O. H. W.; Gummin, M. A.; Ravinett, T.; Jelinsky, S. R.; Edgar, M.

    1995-01-01

    Small pore size microchannel plates (MCP's) are needed to satisfy the requirements for future high resolution small and large format detectors for astronomy. MCP's with pore sizes in the range 5 micron to 8 micron are now being manufactured, but they are of limited availability and are of small size. We have obtained sets of Galileo 8 micron and 6.5 micron MCP's, and Philips 6 micron and 7 micron pore MCP's, and compared them to our larger pore MCP Z stacks. We have tested back to back MCP stacks of four of these MCP's and achieved gains greater than 2 x 1O(exp 7) with pulse height distributions of less than 40% FWHM, and background rates of less than 0.3 events sec(exp -1) cm(exp -2). Local counting rates up to approx. 100 events/pore/sec have been attained with little drop of the MCP gain. The bare MCP quantum efficiencies are somewhat lower than those expected, however. Flat field images are characterized by an absence of MCP fixed pattern noise.

  12. Crystal Ice Formation of Solution and Its Removal Phenomena From Cooled Solid Surface

    NASA Astrophysics Data System (ADS)

    Hirata, Tetsuo; Ishikawa, Masaaki; Nagasaka, Kouji

    Experimental studies for freezing phenomena of ethylene glycol solution on cooled plate have been performed. A polyvinyl chloride as well as an acrylic resin plates are used for the cooled plates. It is found that the crystal ice formed at the cooled plate is removed from the plate due to buoyancy force acting the crystal ice. It means that ice formation on a cooled plate without deposit ice layer is possible by the present method. It is shown that the cooled plate surface is under cooled about 1.0~1.5 degree below the freezing temperature of the solution during the crystal ice formation and its removal phenomena. The degree of under cooled temperature is unaffected by the cooling temperature of the plate. For higher concentration of solution, it is found that the number of the removed crystal ice per unit time is increased and the volume of each removed ice is decreased.

  13. COMPPAP - COMPOSITE PLATE BUCKLING ANALYSIS PROGRAM (UNIX VERSION)

    NASA Technical Reports Server (NTRS)

    Smith, J. P.

    1994-01-01

    The Composite Plate Buckling Analysis Program (COMPPAP) was written to help engineers determine buckling loads of orthotropic (or isotropic) irregularly shaped plates without requiring hand calculations from design curves or extensive finite element modeling. COMPPAP is a one element finite element program that utilizes high-order displacement functions. The high order of the displacement functions enables the user to produce results more accurate than traditional h-finite elements. This program uses these high-order displacement functions to perform a plane stress analysis of a general plate followed by a buckling calculation based on the stresses found in the plane stress solution. The current version assumes a flat plate (constant thickness) subject to a constant edge load (normal or shear) on one or more edges. COMPPAP uses the power method to find the eigenvalues of the buckling problem. The power method provides an efficient solution when only one eigenvalue is desired. Once the eigenvalue is found, the eigenvector, which corresponds to the plate buckling mode shape, results as a by-product. A positive feature of the power method is that the dominant eigenvalue is the first found, which is this case is the plate buckling load. The reported eigenvalue expresses a load factor to induce plate buckling. COMPPAP is written in ANSI FORTRAN 77. Two machine versions are available from COSMIC: a PC version (MSC-22428), which is for IBM PC 386 series and higher computers and compatibles running MS-DOS; and a UNIX version (MSC-22286). The distribution medium for both machine versions includes source code for both single and double precision versions of COMPPAP. The PC version includes source code which has been optimized for implementation within DOS memory constraints as well as sample executables for both the single and double precision versions of COMPPAP. The double precision versions of COMPPAP have been successfully implemented on an IBM PC 386 compatible running

  14. COMPPAP - COMPOSITE PLATE BUCKLING ANALYSIS PROGRAM (IBM PC VERSION)

    NASA Technical Reports Server (NTRS)

    Smith, J. P.

    1994-01-01

    The Composite Plate Buckling Analysis Program (COMPPAP) was written to help engineers determine buckling loads of orthotropic (or isotropic) irregularly shaped plates without requiring hand calculations from design curves or extensive finite element modeling. COMPPAP is a one element finite element program that utilizes high-order displacement functions. The high order of the displacement functions enables the user to produce results more accurate than traditional h-finite elements. This program uses these high-order displacement functions to perform a plane stress analysis of a general plate followed by a buckling calculation based on the stresses found in the plane stress solution. The current version assumes a flat plate (constant thickness) subject to a constant edge load (normal or shear) on one or more edges. COMPPAP uses the power method to find the eigenvalues of the buckling problem. The power method provides an efficient solution when only one eigenvalue is desired. Once the eigenvalue is found, the eigenvector, which corresponds to the plate buckling mode shape, results as a by-product. A positive feature of the power method is that the dominant eigenvalue is the first found, which is this case is the plate buckling load. The reported eigenvalue expresses a load factor to induce plate buckling. COMPPAP is written in ANSI FORTRAN 77. Two machine versions are available from COSMIC: a PC version (MSC-22428), which is for IBM PC 386 series and higher computers and compatibles running MS-DOS; and a UNIX version (MSC-22286). The distribution medium for both machine versions includes source code for both single and double precision versions of COMPPAP. The PC version includes source code which has been optimized for implementation within DOS memory constraints as well as sample executables for both the single and double precision versions of COMPPAP. The double precision versions of COMPPAP have been successfully implemented on an IBM PC 386 compatible running

  15. Battery plate containing filler with conductive coating

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1986-01-01

    The plate (10) comprises a matrix or binder resin phase (12) in which is dispersed particulate, conductive tin oxide such as tin oxide coated glass fibers (14). A monopolar plate (11) is prepared by coating a layer (18) of electrolytically active material onto a surface of the plate (10). Tin oxide is prevented from reduction by coating a surface of the plate (10) with a conductive, impervious layer resistant to reduction such as a thin film (22) of lead adhered to the plate with a layer (21) of conductive adhesive. The plate (10) can be formed by casting a molten dispersion from mixer (36) onto a sheet (30) of lead foil or by passing an assembly of a sheet (41) of resin, a sheet (43) of fiberglass and a sheet (45) of lead between the nip of heated rollers (48, 50).

  16. Excitation and Characterization of Chladni Plate Patterns

    NASA Astrophysics Data System (ADS)

    Bourke, Shannon; Behringer, Ernest

    2011-04-01

    When a thin metal plate with a small amount of sand on it is made to vibrate, aesthetically pleasing sand patterns can form along the nodal lines of the plate. These symmetric patterns are called Chladni Patterns. Students taking PHY 101 Physical Science in the Arts at Eastern Michigan University create these patterns by pulling a violin bow across the edge of a plate, or by using a mechanical oscillator to drive the center of a plate. These two methods only allow a small subset of all possible points on the plate to be excited. We designed and built an electronic device that allows its user to excite the plate at any point. We present patterns created with this electronic device and other methods, and describe ways to model the observed patterns.

  17. Membrane- and plate-type acoustic metamaterials.

    PubMed

    Huang, Tai-Yun; Shen, Chen; Jing, Yun

    2016-06-01

    Over the past decade there has been a great amount of research effort devoted to the topic of acoustic metamaterials (AMMs). The recent development of AMMs has enlightened the way of manipulating sound waves. Several potential applications such as low-frequency noise reduction, cloaking, angular filtering, subwavelength imaging, and energy tunneling have been proposed and implemented by the so-called membrane- or plate-type AMMs. This paper aims to offer a thorough overview on the recent development of membrane- or plate-type AMMs. The underlying mechanism of these types of AMMs for tuning the effective density will be examined first. Four different groups of membrane- or plate-type AMMs (membranes with masses attached, plates with masses attached, membranes or plates without masses attached, and active AMMs) will be reviewed. The opportunities, limitations, and challenges of membrane- or plate-type AMMs will be also discussed.

  18. Membrane- and plate-type acoustic metamaterials.

    PubMed

    Huang, Tai-Yun; Shen, Chen; Jing, Yun

    2016-06-01

    Over the past decade there has been a great amount of research effort devoted to the topic of acoustic metamaterials (AMMs). The recent development of AMMs has enlightened the way of manipulating sound waves. Several potential applications such as low-frequency noise reduction, cloaking, angular filtering, subwavelength imaging, and energy tunneling have been proposed and implemented by the so-called membrane- or plate-type AMMs. This paper aims to offer a thorough overview on the recent development of membrane- or plate-type AMMs. The underlying mechanism of these types of AMMs for tuning the effective density will be examined first. Four different groups of membrane- or plate-type AMMs (membranes with masses attached, plates with masses attached, membranes or plates without masses attached, and active AMMs) will be reviewed. The opportunities, limitations, and challenges of membrane- or plate-type AMMs will be also discussed. PMID:27369148

  19. Battery plate containing filler with conductive coating

    NASA Technical Reports Server (NTRS)

    Rowlette, John J. (Inventor)

    1985-01-01

    The plate (10) comprises a matrix or binder resin phase (12) in which is dispersed particulate, conductive tin oxide such as tin oxide coated glass fibers (14). A monopolar plate (11) is prepared by coating a layer (18) of electrolytically active material onto a surface of the plate (10). Tin oxide is prevented from reduction by coating a surface of the plate (10) with a conductive, impervious layer resistant to reduction such as a thin film (22) of lead adhered to the plate with a layer (21) of conductive adhesive. The plate (10) can be formed by casting a molten dispersion from mixer (36) onto a sheet (30) of lead foil or by passing an assembly of a sheet (41) of resin, a sheet (43) of fiberglass and a sheet (45) of lead between the nip of heated rollers (48, 50).

  20. Rapidly Moving Divertor Plates In A Tokamak

    SciTech Connect

    S. Zweben

    2011-05-16

    It may be possible to replace conventional actively cooled tokamak divertor plates with a set of rapidly moving, passively cooled divertor plates on rails. These plates would absorb the plasma heat flux with their thermal inertia for ~10-30 sec, and would then be removed from the vessel for processing. When outside the tokamak, these plates could be cooled, cleaned, recoated, inspected, and then returned to the vessel in an automated loop. This scheme could provide nearoptimal divertor surfaces at all times, and avoid the need to stop machine operation for repair of damaged or eroded plates. We describe various possible divertor plate designs and access geometries, and discuss an initial design for a movable and removable divertor module for NSTX-U.

  1. Overriding Plate Deformation During Subduction Evolution

    NASA Astrophysics Data System (ADS)

    Davies, J. H.; Garel, F.; Davies, R.; Goes, S. D. B.

    2015-12-01

    Subduction dynamics has been widely studied in free subduction models, which document the important control of the downgoing plate. However, various models have shown how the overriding plate can influence subduction dynamics through its thermal structure, thickness and coupling. Using the code Fluidity we investigate overriding plate deformation in a 2-D thermo-mechanical model of the two-plate subduction system. We use Fluidity's adaptive mesh and free-surface formulation. The model includes a composite temperature- and stress-dependent rheology, and plates are decoupled by a weak layer, which allows for free trench motion. We focus on the evolution of the topography and state of stress in the overriding plate during the different phases of the subduction process: early stages of subduction, free-fall sinking in the upper mantle and interaction of the slab with the high-viscosity lower mantle.

  2. Coupling between plate vibration and acoustic radiation

    NASA Technical Reports Server (NTRS)

    Frendi, Abdelkader; Maestrello, Lucio; Bayliss, Alvin

    1992-01-01

    A detailed numerical investigation of the coupling between the vibration of a flexible plate and the acoustic radiation is performed. The nonlinear Euler equations are used to describe the acoustic fluid while the nonlinear plate equation is used to describe the plate vibration. Linear, nonlinear, and quasi-periodic or chaotic vibrations and the resultant acoustic radiation are analyzed. We find that for the linear plate response, acoustic coupling is negligible. However, for the nonlinear and chaotic responses, acoustic coupling has a significant effect on the vibration level as the loading increases. The radiated pressure from a plate undergoing nonlinear or chaotic vibrations is found to propagate nonlinearly into the far-field. However, the nonlinearity due to wave propagation is much weaker than that due to the plate vibrations. As the acoustic wave propagates into the far-field, the relative difference in level between the fundamental and its harmonics and subharmonics decreases with distance.

  3. Toward Microbioreactor Arrays: A Slow-Responding Oxygen Sensor for Monitoring of Microbial Cultures in Standard 96-Well Plates.

    PubMed

    Glauche, Florian; John, Gernot T; Arain, Sarina; Knepper, Andreas; Neubauer, Antje; Goelling, Detlef; Lang, Christine; Violet, Norman; King, Rudibert; Neubauer, Peter

    2015-08-01

    In this study, a slow-responding chemo-optical sensor for dissolved oxygen (DO) integrated into a 96-well plate was developed. The slow response time ensures that the measured oxygen value does not change much during plate transport to the microplate reader. The sensor therefore permits at-line DO measurement of microbial cultures. Moreover, it eliminates the necessity of individual optical measurement systems for each culture plate, as many plates can be measured successively. Combined with the 96-well format, this increases the experimental throughput enormously. The novel sensor plate (Slow OxoPlate) consists of fluorophores suspended in a polymer matrix that were placed into u-bottom 96-well plates. Response time was measured using sodium sulfite, and a t90 value of 9.7 min was recorded. For application, DO values were then measured in Escherichia coli and Saccharomyces cerevisiae cultures grown under fed-batch-like conditions. Depending on the DO sensor's response time, different information on the oxygenation state of the culture plate was obtained: a fast sensor variant detects disturbance through sampling, whereas the slow sensor indicates oxygen limitation during incubation. A combination of the commercially available OxoPlate and the Slow OxoPlate enables operators of screening facilities to validate their cultivation procedures with regard to oxygen availability. PMID:25720599

  4. Toward Microbioreactor Arrays: A Slow-Responding Oxygen Sensor for Monitoring of Microbial Cultures in Standard 96-Well Plates.

    PubMed

    Glauche, Florian; John, Gernot T; Arain, Sarina; Knepper, Andreas; Neubauer, Antje; Goelling, Detlef; Lang, Christine; Violet, Norman; King, Rudibert; Neubauer, Peter

    2015-08-01

    In this study, a slow-responding chemo-optical sensor for dissolved oxygen (DO) integrated into a 96-well plate was developed. The slow response time ensures that the measured oxygen value does not change much during plate transport to the microplate reader. The sensor therefore permits at-line DO measurement of microbial cultures. Moreover, it eliminates the necessity of individual optical measurement systems for each culture plate, as many plates can be measured successively. Combined with the 96-well format, this increases the experimental throughput enormously. The novel sensor plate (Slow OxoPlate) consists of fluorophores suspended in a polymer matrix that were placed into u-bottom 96-well plates. Response time was measured using sodium sulfite, and a t90 value of 9.7 min was recorded. For application, DO values were then measured in Escherichia coli and Saccharomyces cerevisiae cultures grown under fed-batch-like conditions. Depending on the DO sensor's response time, different information on the oxygenation state of the culture plate was obtained: a fast sensor variant detects disturbance through sampling, whereas the slow sensor indicates oxygen limitation during incubation. A combination of the commercially available OxoPlate and the Slow OxoPlate enables operators of screening facilities to validate their cultivation procedures with regard to oxygen availability.

  5. Optimal Planet Properties For Plate Tectonics Through Time And Space

    NASA Astrophysics Data System (ADS)

    Stamenkovic, Vlada; Seager, Sara

    2014-11-01

    Both the time and the location of planet formation shape a rocky planet’s mass, interior composition and structure, and hence also its tectonic mode. The tectonic mode of a planet can vary between two end-member solutions, plate tectonics and stagnant lid convection, and does significantly impact outgassing and biogeochemical cycles on any rocky planet. Therefore, estimating how the tectonic mode of a planet is affected by a planet’s age, mass, structure, and composition is a major step towards understanding habitability of exoplanets and geophysical false positives to biosignature gases. We connect geophysics to astronomy in order to understand how we could identify and where we could find planet candidates with optimal conditions for plate tectonics. To achieve this goal, we use thermal evolution models, account for the current wide range of uncertainties, and simulate various alien planets. Based on our best model estimates, we predict that the ideal targets for plate tectonics are oxygen-dominated (C/O<1) (solar system like) rocky planets of ~1 Earth mass with surface oceans, large metallic cores super-Mercury, rocky body densities of ~7000kgm-3), and with small mantle concentrations of iron 0%), water 0%), and radiogenic isotopes 10 times less than Earth). Super-Earths, undifferentiated planets, and especially hypothetical carbon planets, speculated to consist of SiC and C, are not optimal for the occurrence of plate tectonics. These results put Earth close to an ideal compositional and structural configuration for plate tectonics. Moreover, the results indicate that plate tectonics might have never existed on planets formed soon after the Big Bang—but instead is favored on planets formed from an evolved interstellar medium enriched in iron but depleted in silicon, oxygen, and especially in Th, K, and U relative to iron. This possibly sets a belated Galactic start for complex Earth-like surface life if plate tectonics significantly impacts the build up

  6. Anisotropic magnetocapacitance in ferromagnetic-plate capacitors

    NASA Astrophysics Data System (ADS)

    Haigh, J. A.; Ciccarelli, C.; Betz, A. C.; Irvine, A.; Novák, V.; Jungwirth, T.; Wunderlich, J.

    2015-04-01

    The capacitance of a parallel-plate capacitor can depend on the applied magnetic field. Previous studies have identified capacitance changes induced via classical Lorentz force or spin-dependent Zeeman effects. Here we measure a magnetization direction-dependent capacitance in parallel-plate capacitors where one plate is a ferromagnetic semiconductor, gallium manganese arsenide. This anisotropic magnetocapacitance is due to the anisotropy in the density of states dependent on the magnetization through the strong spin-orbit interaction.

  7. High performance flat plate solar collector

    NASA Technical Reports Server (NTRS)

    Lansing, F. L.; Reynolds, R.

    1976-01-01

    The potential use of porous construction is presented to achieve efficient heat removal from a power producing solid and is applied to solar air heaters. Analytical solutions are given for the temperature distribution within a gas-cooled porous flat plate having its surface exposed to the sun's energy. The extracted thermal energy is calculated for two different types of plate transparency. Results show the great improvement in performance obtained with porous flat plate collectors as compared with analogous nonporous types.

  8. High speed thin plate fatigue crack monitor

    NASA Technical Reports Server (NTRS)

    Wincheski, Buzz A. (Inventor); Heyman, Joseph S. (Inventor); Namkung, Min (Inventor); Fulton, James P. (Inventor)

    1996-01-01

    A device and method are provided which non-destructively detect crack length and crack geometry in thin metallic plates. A non-contacting vibration apparatus produces resonant vibrations without introducing extraneous noise. Resulting resonant vibration shifts in cracked plates are correlated to known crack length in plates with similar resonant vibration shifts. In addition, acoustic emissions of cracks at resonance frequencies are correlated to acoustic emissions from known crack geometries.

  9. Real time monitoring of electroless nickel plating

    NASA Astrophysics Data System (ADS)

    Rains, Aaron E.; Kline, Ronald A.

    2013-01-01

    This work deals with the design and manufacturing of the heat and chemical resistant transducer case required for on-line immersion testing, experimental design, data acquisition and signal processing. Results are presented for several depositions with an accuracy of two ten-thousandths of an inch in coating thickness obtained. Monitoring the deposition rate of Electroless Nickel (EN) plating in-situ will provide measurement of the accurate dimensions of the component being plated, in real time. EN is used as for corrosion and wear protection for automotive an - Electroless Nickel (EN) plating is commonly used for corrosion and wear protection for automotive and aerospace components. It plates evenly and symmetrically, theoretically allowing the part to be plated to its final dimension. Currently the standard approach to monitoring the thickness of the deposited nickel is to remove the component from the plating bath and physically measure the part. This can lead to plating problems such as pitting, non-adhesion of the deposit and contamination of the plating solution. The goal of this research effort is to demonstrate that plating thickness can be rapidly and accurately measured using ultrasonic testing. Here a special housing is designed to allow immersion of the ultrasonic transducers directly into the plating bath. An FFT based signal processing algorithm was developed to resolve closely spaced echoes for precise thickness determination. The technique in this research effort was found to be capable of measuring plating thicknesses to within 0.0002 inches. It is expected that this approach will lead to cost savings in many EN plating operations.

  10. Avionics Box Cold Plate Damage Prevention

    NASA Technical Reports Server (NTRS)

    Stambolian, Damon; Larcher, Steven; Henderson, Gena; Tran, Donald

    2011-01-01

    Over the years there have been several occurrences of damage to Space Shuttle Orbiter cold plates during removal and replacement of avionics boxes. Thus a process improvement team was put together to determine ways to prevent these kinds of damage. From this effort there were many solutions including, protective covers, training, and improved operations instructions. The focus of this paper is to explain the cold plate damage problem and the corrective actions for preventing future damage to aerospace avionics cold plate designs.

  11. Reliability assessment of different plate theories for elastic wave propagation analysis in functionally graded plates.

    PubMed

    Mehrkash, Milad; Azhari, Mojtaba; Mirdamadi, Hamid Reza

    2014-01-01

    The importance of elastic wave propagation problem in plates arises from the application of ultrasonic elastic waves in non-destructive evaluation of plate-like structures. However, precise study and analysis of acoustic guided waves especially in non-homogeneous waveguides such as functionally graded plates are so complicated that exact elastodynamic methods are rarely employed in practical applications. Thus, the simple approximate plate theories have attracted much interest for the calculation of wave fields in FGM plates. Therefore, in the current research, the classical plate theory (CPT), first-order shear deformation theory (FSDT) and third-order shear deformation theory (TSDT) are used to obtain the transient responses of flexural waves in FGM plates subjected to transverse impulsive loadings. Moreover, comparing the results with those based on a well recognized hybrid numerical method (HNM), we examine the accuracy of the plate theories for several plates of various thicknesses under excitations of different frequencies. The material properties of the plate are assumed to vary across the plate thickness according to a simple power-law distribution in terms of volume fractions of constituents. In all analyses, spatial Fourier transform together with modal analysis are applied to compute displacement responses of the plates. A comparison of the results demonstrates the reliability ranges of the approximate plate theories for elastic wave propagation analysis in FGM plates. Furthermore, based on various examples, it is shown that whenever the plate theories are used within the appropriate ranges of plate thickness and frequency content, solution process in wave number-time domain based on modal analysis approach is not only sufficient but also efficient for finding the transient waveforms in FGM plates.

  12. An arbitrarily shaped inclusion with uniform eigencurvatures in an infinite plate, semi-infinite plate, two bonded semi-infinite plates or a circular plate

    NASA Astrophysics Data System (ADS)

    Wang, Xu; Zhou, Kun

    2015-04-01

    Within the framework of the Kirchhoff-Love isotropic and homogeneous plate theory, we obtain, in a unified manner, the analytic solutions to the Eshelby's problem of an inclusion of arbitrary shape with uniform eigencurvatures in an infinite plate, a semi-infinite plate, one of two bonded semi-infinite plates or a circular plate by means of conformal mapping and analytical continuation. The edge of the semi-infinite plate can be rigidly clamped, free or simply supported, while that of the circular plate can be rigidly clamped, free or perfectly bonded to the surrounding infinite plate. Several examples of practical and theoretical interests are presented to demonstrate the general method. In particular, the elementary expressions of the internal elastic fields of bending moments and deflections within an ( n + 1)-fold rotational symmetric inclusion described by a five-term mapping function, a symmetric airfoil cusp inclusion, a symmetric lip cusp inclusion and an inclusion described by a rational mapping function in an infinite plate are derived.

  13. Bipolar plates for PEM fuel cells

    NASA Astrophysics Data System (ADS)

    Middelman, E.; Kout, W.; Vogelaar, B.; Lenssen, J.; de Waal, E.

    The bipolar plates are in weight and volume the major part of the PEM fuel cell stack, and are also a significant contributor to the stack costs. The bipolar plate is therefore a key component if power density has to increase and costs must come down. Three cell plate technologies are expected to reach targeted cost price levels, all having specific advantages and drawbacks. NedStack has developed a conductive composite materials and a production process for fuel cell plates (bipolar and mono-polar). The material has a high electric and thermal conductivity, and can be processed into bipolar plates by a proprietary molding process. Process cycle time has been reduced to less than 10 s, making the material and process suitable for economical mass production. Other development work to increase material efficiency resulted in thin bipolar plates with integrated cooling channels, and integrated seals, and in two-component bipolar plates. Total thickness of the bipolar plates is now less than 3 mm, and will be reduced to 2 mm in the near future. With these thin integrated plates it is possible to increase power density up to 2 kW/l and 2 kW/kg, while at the same time reducing cost by integrating other functions and less material use.

  14. Wave propagation in metamaterial lattice sandwich plates

    NASA Astrophysics Data System (ADS)

    Fang, Xin; Wen, Jihong; Yin, Jianfei; Yu, Dianlong

    2016-04-01

    This paper designed a special acoustic metamaterial 3D Kagome lattice sandwich plate. Dispersion properties and vibration responses of both traditional plate and metamaterial plate are investigated based on FEA methods. The traditional plate does not have low-frequency complete bandgaps, but the metamaterial plate has low-frequency complete bandgap (at 620Hz) coming from the symmetrical local cantilever resonators. The bandgap frequency is approximate to the first-order natural frequency of the oscillator. Complex wave modes are analyzed. The dispersion curves of longitudinal waves exist in the flexural bandgap. The dispersion properties demonstrate the metamaterial design is advantageous to suppress the low-frequency flexural wave propagation in lattice sandwich plate. The flexural vibrations near the bandgap are also suppressed efficiently. The longitudinal excitation stimulates mainly longitudinal waves and lots of low-frequency flexural vibration modes are avoided. Furthermore, the free edge effects in metamaterial plate provide new method for damping optimizations. The influences of damping on vibrations of the metamaterial sandwich plate are studied. Damping has global influence on the wave propagation; stronger damping will induce more vibration attenuation. The results enlighten us damping and metamaterial design approaches can be unite in the sandwich plates to suppress the wave propagations.

  15. Plate electrode arrangement for an electrostatic precipitator

    SciTech Connect

    Wooldridge, J.E.

    1982-06-01

    An electrode plate arrangement for an electrostatic precipitator including a plurality of essentially identical plate assemblies secured in an opposing fashion to the opposite sides of a gridlike mounting frame extending across the interior of the precipitator. The plate assemblies on the upstream side of the frame include an ionizing zone for the dirty gas stream which feeds into serially aligned collecting zones in the opposing assemblies which in turn feed into a deionizing zone in the plate assemblies on the downstream side of the frame.

  16. Plate Tectonics: A Paradigm under Threat.

    ERIC Educational Resources Information Center

    Pratt, David

    2000-01-01

    Discusses the challenges confronting plate tectonics. Presents evidence that contradicts continental drift, seafloor spreading, and subduction. Reviews problems posed by vertical tectonic movements. (Contains 242 references.) (DDR)

  17. Fuel cell cooler-humidifier plate

    DOEpatents

    Vitale, Nicholas G.; Jones, Daniel O.

    2000-01-01

    A cooler-humidifier plate for use in a proton exchange membrane (PEM) fuel cell stack assembly is provided. The cooler-humidifier plate combines functions of cooling and humidification within the fuel cell stack assembly, thereby providing a more compact structure, simpler manifolding, and reduced reject heat from the fuel cell. Coolant on the cooler side of the plate removes heat generated within the fuel cell assembly. Heat is also removed by the humidifier side of the plate for use in evaporating the humidification water. On the humidifier side of the plate, evaporating water humidifies reactant gas flowing over a moistened wick. After exiting the humidifier side of the plate, humidified reactant gas provides needed moisture to the proton exchange membranes used in the fuel cell stack assembly. The invention also provides a fuel cell plate that maximizes structural support within the fuel cell by ensuring that the ribs that form the boundaries of channels on one side of the plate have ends at locations that substantially correspond to the locations of ribs on the opposite side of the plate.

  18. Limit cycle oscillation of a fluttering plate

    NASA Astrophysics Data System (ADS)

    Ye, Wei-Liang

    1992-09-01

    The limit cycle oscillation for a cantilever plate in a uniform flow stream is investigated. Von Karman's theory for a large deflection plate and quasi-steady aerodynamic theory are assumed. The equations for computing the nonlinear oscillation of a fluttering cantilever plate are derived by means of Rayleigh-Ritz approach. Lagrange's equations and a set of mode function expansions are employed. Time marching simulation is used to determine the limit cycle oscillation and fluttering boundary. The results indicate that the modal expansion is of convergence. The length-to-width ratio of a plate has a great effect on the flutter amplitude of the limit cycle.

  19. MACMA: a Virtual Lab for Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Grigne, C.; Combes, M.; Tisseau, C.

    2013-12-01

    MACMA (Multi-Agent Convective MAntle) is a tool developed to simulate evolutive plate tectonics and mantle convection in a 2-D cylindrical geometry (Combes et al., 2012). The model relies mainly on a force balance to compute the velocity of each plate, and on empirical rules to determine how plate boundaries move and evolve. It includes first-order features of plate tectonics: (a) all plates on Earth do not have the same size, (b) subduction zones are asymmetric, (c) plates driven by subducting slabs and upper plates do not exhibit the same velocities, and (d) plate boundaries are mobile, can collide, merge and disappear, and new plate boundaries can be created. The MACMA interface was designed to be user-friendly and a simple use of the simulator can be achieved without any prerequisite knowledge in fluid dynamics, mantle rheology, nor in numerical methods. As a preliminary study, the simulator was used by a few students from bachelor's degree to master's degree levels. An initial configuration for plate tectonics has to be created before starting a simulation: the number and types of plate boundaries (ridge, subduction, passive margins) has to be defined and seafloor ages must be given. A simple but interesting exercise consists in letting students build such an initial configuration: they must analyze a map of tectonic plates, choose a 2-D section and examine carefully a map of seafloor ages. Students mentioned that the exercise made them realize that the 3-D spherical structure of plate tectonics does not translate directly in a simple 2-D section, as opposed to what is usually shown in books. Physical parameters: e.g. mantle viscosity, number of layers to consider in the mantle (upper and lower mantle, possible asthenosphere), initial time and mantle temperature, have to be chosen, and students can use this virtual lab to see how different scenarios emerge when parameters are varied. Very importantly, the direct visualization of the mobility of plate

  20. Seismic observations of large-scale deformation at the bottom of fast-moving plates

    NASA Astrophysics Data System (ADS)

    Debayle, E.; Ricard, Y. R.

    2012-12-01

    We investigate the global SV-wave azimuthal anisotropy from a new dataset of around 375 000 fundamental and higher mode Rayleigh waveforms. Our azimuthal anisotropy model improves upon DKP2005 seismic model (Debayle et al., Nature 2005) through a larger dataset (expanded by a factor 3.8) and a new approach which allows us to better extract fundamental and higher mode information. Our results confirm that in average, azimuthal anisotropy is significant only in the uppermost 200-250 km of the upper mantle and weak below. A clear root square of age dependence of anisotropy is observed beneath oceanic plates. The anisotropy projected in the direction of plate motion is more or less proportional to the plate velocity. Plate-scale present-day deformation is remarkably well recorded beneath the fastest moving plates (Indo-Australian, Coco, Nazca, Philippine Sea and Pacific plates). Under these plates, the amplitude of anisotropy does not change much with the distance to the ridge, indicating that the lattice preferred orientation rotates and saturates quickly. Beneath slower plates, plate-motion parallel anisotropy is observed only locally, which suggests, not surprisingly that the convection flow is only partly controlled by the surface motion. Within the lithosphere itself, the anisotropy is weak and likely frozen in; rather aligned with the plate velocity at its age of formation which is recorded by the local age gradient, than with the present-day motion. Although for young ages, the difference between the velocity recorded by the isochrons and the present-day velocity is small, for ages larger than 80 ~myrs the anisotropy rotates with depth from the fossil direction in the lithosphere to the present-day direction in the asthenosphere. Under fast continents (mostly Australia and India), the present day velocity orients the anisotropy around 150-200 km depth.

  1. Tunable surface plasmon wave plates.

    PubMed

    Djalalian-Assl, Amir; Cadusch, Jasper J; Balaur, Eugeniu; Aramesh, Morteza

    2016-07-01

    The highest resonant transmission through an array of holes perforated in metallic screens occurs when the dielectric constant of the substrate, the superstrate, and the hole are the same. Changes in the refractive index of the homogenous environment also produce the largest shift in resonances per refractive index unit. In this Letter, we first propose and apply a technique in realization of a freestanding bi-periodic array of holes perforated in a silver film. We then show both numerically and experimentally that shifts in (1,0) and (0,1) modes in response to changes in the refractive index of the surrounding dielectric provide a mechanism for realization of a miniaturized tunable quarter-wave plate that operates in an extraordinary optical transmission mode with a high throughput and a near unity state of circularly polarized light. PMID:27367123

  2. Composition of the continental plates

    USGS Publications Warehouse

    Gilluly, J.

    1954-01-01

    The structures of continental plates and of oceanic basins suggested by several seismologists are utilized to estimate the relative volumes of sial and sima in the earth's crust. It seems that sial of the composition of the average igneous rock constitutes fully 26% and perhaps as much as 43% of the total crust. This ratio is far higher than seems likely if the sial had been entirely derived through fractional crystallization of a basaltic magma. The relative paucity of intermediate rocks as compared with granite and gabbro in the crust points in the same direction. The tentative conclusion is reached that the sial owes a large part of its volume to some process other than fractional crystallization of basalt-possibly to the emanation of low-melting constituents such as water, silica, potassa, soda, and alumina directly from the mantle to the crust. ?? 1954 Springer-Verlag.

  3. Waste minimization in chrome plating

    SciTech Connect

    Scheuer, J.; Walter, K.; Nastasi, M.

    1996-09-01

    This is the final report of a one year laboratory directed research and development project at the Los Alamos National Laboratory (LANL). Traditional wet chemical electroplating techniques utilize toxic materials and pose environmental hazards in the disposal of primary baths and waste waters. Pollutants include metals and nonmetals, such as oil, grease, phosphates, and toxic and organic compounds. This project is focused on development of plasma source ion implantation (PSII), a novel and cost-effective surface modification technique, to minimize and ultimately eliminate waste generated in chrome plating. We are collaborating with and industrial partner to design material systems, utilize the PSII processes in existing Los Alamos experimental facilities, and analyze both material and performance characteristics.

  4. Isopachic contouring of opaque plates

    NASA Technical Reports Server (NTRS)

    Post, D.; Asundi, A.; Czarnek, R.

    1984-01-01

    Contour maps of change of thickness of opaque plates subjected to external loads are obtained using holographic interferometry in conjunction with the moire effect. A simple holographic-interferometry arrangement is used first to obtain contour maps of the out-of-plane displacements of the two sides of the object. Carrier patterns of equal magnitude but opposite signs are added to these contours. Superposition of the reconstructed holograms of the two sides produces a pattern of additive-moire fringes, which are contours of change of thickness. Effects of midplane warpage of the loaded specimen are cancelled. Sensitivity is lambda/2 per fringe order, contrast of the isopachic-fringe pattern is excellent, and the process is compatible with a mechanical-testing-machine environment.

  5. Linear and non-linear deflection analysis of thick rectangular plates. 2: Numerical applications

    NASA Astrophysics Data System (ADS)

    Bencharif, N.; Ng, S. F.

    1994-03-01

    literature. The submatrices involved in the formation of the finite difference equations from the governing differential equations are generated directly by the computer program. The subroutine SOLINV using the change of variable technique illustrated elsewhere takes care of the solution of the general system. Simplicity in formulation and quick convergence are the obvious advantages of the finite difference formulation developed to compute small and large deflection analysis of thick plates in comparison with other numerical methods requiring extensive computer facilities.

  6. Inter- and intra-plate deformation at North American plate boundaries

    NASA Technical Reports Server (NTRS)

    Beavan, John

    1986-01-01

    Alaska tectonics and earthquake hazard studies; Southern California tectonics (block rotation); spreading near the Salton Trough; California plate motion (fault zone kinematics); and Caribbean plate motion investigations are examined.

  7. The cartilage extracellular matrix as a transient developmental scaffold for growth plate maturation.

    PubMed

    Melrose, James; Shu, Cindy; Whitelock, John M; Lord, Megan S

    2016-01-01

    The cartilage growth plate is a specialized developmental tissue containing characteristic zonal arrangements of chondrocytes. The proliferative and differentiative states of chondrocytes are tightly regulated at all stages including the initial limb bud and rudiment cartilage stages of development, the establishment of the primary and secondary ossification centers, development of the growth plates and laying down of bone. A multitude of spatio-temporal signals, including transcription factors, growth factors, morphogens and hormones, control chondrocyte maturation and terminal chondrocyte differentiation/hypertrophy, cell death/differentiation, calcification and vascular invasion of the growth plate and bone formation during morphogenetic transition of the growth plate. This involves hierarchical, integrated signaling from growth and factors, transcription factors, mechanosensory cues and proteases in the extracellular matrix to regulate these developmental processes to facilitate progressive changes in the growth plate culminating in bone formation and endochondral ossification. This review provides an overview of selected components which have particularly important roles in growth plate biology including collagens, proteoglycans, glycosaminoglycans, growth factors, proteases and enzymes.

  8. A Treatise on Equivalent-Plate Stiffnesses for Stiffened Laminated-Composite Plates and Plate-Like Lattices

    NASA Technical Reports Server (NTRS)

    Nemeth, Michael P.

    2011-01-01

    A survey of studies conducted since 1914 on the use of equivalent-plate stiffnesses in modeling the overall, stiffness-critical response of stiffened plates and shells is presented. Two detailed, comprehensive derivations of first-approximation equivalent-plate stiffnesses are also presented that are based on the Reissner-Mindlin-type, first-order transverse-shear deformation theory for anisotropic plates. Equivalent-plate stiffness expressions, and a corresponding symbolic manipulation computer program, are also presented for several different stiffener configurations. These expressions are very general and exhibit the full range of anisotropies permitted by the Reissner-Mindlin-type, first-order transverse-shear deformation theory for anisotropic plates. The expressions presented in the present study were also compared with available, previously published results. For the most part, the previously published results are for special cases of the general expressions presented herein and are almost in complete agreement. Analysis is also presented that extends the use of the equivalent-plate stiffness expressions to sandwich plates.

  9. Improved Late Cretaceous and early Cenozoic Paleomagnetic apparent polar wander path for the Pacific plate

    NASA Astrophysics Data System (ADS)

    Beaman, Melissa; Sager, William W.; Acton, Gary D.; Lanci, Luca; Pares, Josep

    2007-10-01

    Understanding of Pacific plate tectonics and geodynamics is aided by refinement of the plate's apparent polar wander path (APWP). We improved the Late Cretaceous and early Cenozoic APWP by analyzing a large, diverse paleomagnetic data set that combines core sample, seamount magnetic anomaly model, and marine magnetic anomaly skewness data. Our preferred APWP has five mean paleomagnetic poles representing the Oligocene (30 Ma), Late (39 Ma) and Early (49 Ma) Eocene, and Paleocene (61 Ma) epochs and the Maastrichtian (68 Ma) stage. Along with a published 80 Ma pole, the APWP shows a stillstand from ˜ 80 to ˜ 49 Ma punctuating the large overall northward drift of the plate. The two youngest poles imply resumption of northward motion during mid-Eocene time with another change of polar motion after ˜ 30 Ma. If unaffected by other phenomena (e.g., true polar wander or change in time-averaged magnetic field geometry), the stillstand implies negligible northward plate motion during the period of Emperor Seamounts formation, contrary to most accepted plate motion models. The stillstand is consistent with paleomagnetic data from the Emperor Seamounts, which imply southward motion of the Hawaiian melting anomaly. It also implies significant westward drift of the hotspot if the Pacific plate was moving west at rates similar to the later Cenozoic. In addition, changes in polar wander after ˜ 49 Ma are consistent with changes of north Pacific plate boundaries.

  10. Seismic anisotropy: tracing plate dynamics in the mantle.

    PubMed

    Park, Jeffrey; Levin, Vadim

    2002-04-19

    Elastic anisotropy is present where the speed of a seismic wave depends on its direction. In Earth's mantle, elastic anisotropy is induced by minerals that are preferentially oriented in a directional flow or deformation. Earthquakes generate two seismic wave types: compressional (P) and shear (S) waves, whose coupling in anisotropic rocks leads to scattering, birefringence, and waves with hybrid polarizations. This varied behavior is helping geophysicists explore rock textures within Earth's mantle and crust, map present-day upper-mantle convection, and study the formation of lithospheric plates and the accretion of continents in Earth history.

  11. PlateRunner: A Search Engine to Identify EMR Boilerplates.

    PubMed

    Divita, Guy; Workman, T Elizabeth; Carter, Marjorie E; Redd, Andrew; Samore, Matthew H; Gundlapalli, Adi V

    2016-01-01

    Medical text contains boilerplated content, an artifact of pull-down forms from EMRs. Boilerplated content is the source of challenges for concept extraction on clinical text. This paper introduces PlateRunner, a search engine on boilerplates from the US Department of Veterans Affairs (VA) EMR. Boilerplates containing concepts should be identified and reviewed to recognize challenging formats, identify high yield document titles, and fine tune section zoning. This search engine has the capability to filter negated and asserted concepts, save and search query results. This tool can save queries, search results, and documents found for later analysis.

  12. ZnO nanorods/plates on Si substrate grown by low-temperature hydrothermal reaction

    NASA Astrophysics Data System (ADS)

    Gao, S. Y.; Li, H. D.; Yuan, J. J.; Li, Y. A.; Yang, X. X.; Liu, J. W.

    2010-02-01

    The zinc oxide (ZnO) nanorods/plates are obtained via hydrothermal method assisted by etched porous Al film on Si substrate. The products consist of nanorods with average diameter of 100 nm and nanoplates with thickness of 200-300 nm, which are uniformly distributed widely and grown perpendicularly to the substrate. The ZnO nanoplates with thickness of 150-300 nm were grown on Si substrate coated with a thin continuous Al film (without etching) in the same aqueous solution. The growth mechanism and room temperature photoluminescence (PL) properties of ZnO nanorods/plates and nanoplates were investigated. It is found that the introduction of the etched Al film plays a key role in the formation of ZnO nanorods/plates. The annealing process is favorable to enhance the UV PL emissions of the ZnO nanorods/plates.

  13. Simulation of Evolutive Plate Tectonics: the Size of Plates Depends on Mantle Temperature

    NASA Astrophysics Data System (ADS)

    Grigne, C.; Combes, M.

    2013-12-01

    We use a dynamic model of plate tectonics based on a multiagent approach, in a 2D cylindrical geometry (Combes et al., 2012), to study how evolutive plate tectonics affect the long term thermal state of the mantle, and in return, to analyze the relationship between the mantle mean temperature and the geometry of plate tectonics. Our model accounts for first-order features of plate tectonics: (a) all plates on Earth do not have the same size, (b) subduction zones are asymmetric, (c) plates driven by subducting slabs and upper plates do not exhibit the same velocities, and (d) plate boundaries are mobile, can collide, merge and disappear, and new plate boundaries can be created. We show that when processes for plate boundary creation (subduction initiation and ridge creation) are relying on a brittle criterion, namely when a fixed yield strength has to be reached, the average size of plates adapts to the mantle thermal state: longer plates are obtained for a hotter mantle, which implies a maximum seafloor age that remains fairly high throughout Earth's thermal history and limits mantle heat loss. This is consistent with petrological and geochemical constraints on Earth's cooling history. Important fluctuations in the mantle heat flux and velocities of plates are obtained on a timescale of a few hundred Myr, but on the long term, the relationship between the average wavelength of plate tectonics and mantle temperature can be explained by a simple scaling law. Recent compilations of geological records infer that passive margins had longer lifespans in the past (e.g. Bradley 2008; 2011), which has been linked to 'sluggish' plate tectonics and slow plates in the Precambrian (Korenaga, 2006). Our simulations outputs include lifespans of tectonic entities such as passive margins, as well as statistical data about events of plates reorganizations. We obtain faster plates in the past than at present day, but counterintuitively we also observe a low episodicity of tectonic

  14. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Tie plates. 213.123 Section 213.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5...

  15. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Tie plates. 213.123 Section 213.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5...

  16. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Tie plates. 213.123 Section 213.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5...

  17. 49 CFR 213.123 - Tie plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Tie plates. 213.123 Section 213.123 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRACK SAFETY STANDARDS Track Structure § 213.123 Tie plates. (a) In Classes 3 through 5...

  18. Pressure-Letdown Plates for Coal Gasifiers

    NASA Technical Reports Server (NTRS)

    Collins, E. R., Jr.

    1985-01-01

    Variation of pseudoporous plates used with coal gasifiers in pressure letdown stage of processing minimize clogging. Rotating plates containing variable gap annuli continually change flow path to enable erosionless reduction of gas pressure. Particles that otherwise clog porous plugs pass through gaps.

  19. Vacuum fusion bonding of glass plates

    DOEpatents

    Swierkowski, Steve P.; Davidson, James C.; Balch, Joseph W.

    2000-01-01

    An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn. The apparatus and method may be used to fabricate microcapillary arrays for chemical electrophoresis; for example, any apparatus using a network of microfluidic channels embedded between plates of glass or similar moderate melting point substrates with a gradual softening point curve, or for assembly of glass-based substrates onto larger substrates, such as in flat panel display systems.

  20. Vacuum fusion bonding of glass plates

    DOEpatents

    Swierkowski, Steve P.; Davidson, James C.; Balch, Joseph W.

    2001-01-01

    An improved apparatus and method for vacuum fusion bonding of large, patterned glass plates. One or both glass plates are patterned with etched features such as microstructure capillaries and a vacuum pumpout moat, with one plate having at least one hole therethrough for communication with a vacuum pumpout fixture. High accuracy alignment of the plates is accomplished by a temporary clamping fixture until the start of the fusion bonding heat cycle. A complete, void-free fusion bond of seamless, full-strength quality is obtained through the plates; because the glass is heated well into its softening point and because of a large, distributed force that is developed that presses the two plates together from the difference in pressure between the furnace ambient (high pressure) and the channeling and microstructures in the plates (low pressure) due to the vacuum drawn. The apparatus and method may be used to fabricate microcapillary arrays for chemical electrophoresis; for example, any apparatus using a network of microfluidic channels embedded between plates of glass or similar moderate melting point substrates with a gradual softening point curve, or for assembly of glass-based substrates onto larger substrates, such as in flat panel display systems.

  1. Improved nickel plating of Inconel X-750

    NASA Technical Reports Server (NTRS)

    Farmer, M. E.; Feeney, J. E.; Kuster, C. A.

    1969-01-01

    Electroplating technique with acid pickling provides a method of applying nickel plating on Inconel X-750 tubing to serve as a wetting agent during brazing. Low-stress nickel-plating bath contains no organic wetting agents that cause the nickel to blister at high temperatures.

  2. Spiral plate method for bacterial determination.

    PubMed

    Gilchrist, J E; Campbell, J E; Donnelly, C B; Peeler, J T; Delaney, J M

    1973-02-01

    A method is described for determining the number of bacteria in a solution by the use of a machine which deposits a known volume of sample on a rotating agar plate in an ever decreasing amount in the form of an Archimedes spiral. After the sample is incubated, different colony densities are apparent on the surface of the plate. A modified counting grid is described which relates area of the plate of volume of sample. By counting an appropriate area of the plate, the number of bacteria in the sample is estimated. This method was compared to the pour plate procedure with the use of pure and mixed cultures in water and milk. The results did not demonstrate a significant difference in variance between duplicates at the alpha = 0.01 level when concentrations of 600 to 12 x 10(5) bacteria per ml were used, but the spiral plate method gave counts that were higher than counts obtained by the pour plate method. The time and materials required for this method are substantially less than those required for the conventional aerobic pour plate procedure.

  3. 30 CFR 22.10 - Approval plate.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.10 Approval plate. (a) Attachment to be made by manufacturers. (1) Manufacturers shall attach, stamp, or mold an approval plate on each permissible methane... follows: Permissible Methane Detector (or Permissible Methane Indicating Detector) Approval No. ___...

  4. 30 CFR 22.10 - Approval plate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.10 Approval plate. (a) Attachment to be made by manufacturers. (1) Manufacturers shall attach, stamp, or mold an approval plate on each permissible methane... follows: Permissible Methane Detector (or Permissible Methane Indicating Detector) Approval No. ___...

  5. 30 CFR 22.10 - Approval plate.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... MINING PRODUCTS PORTABLE METHANE DETECTORS § 22.10 Approval plate. (a) Attachment to be made by manufacturers. (1) Manufacturers shall attach, stamp, or mold an approval plate on each permissible methane... follows: Permissible Methane Detector (or Permissible Methane Indicating Detector) Approval No. ___...

  6. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  7. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  8. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  9. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  10. 49 CFR 236.779 - Plate, top.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Plate, top. 236.779 Section 236.779 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.779 Plate, top....

  11. Computing relative plate velocities: a primer

    SciTech Connect

    Bevis, M.

    1987-08-01

    Standard models of present-day plate motions are framed in terms of rates and poles of rotation, in accordance with the well-known theorem due to Euler. This article shows how computation of relative plate velocities from such models can be viewed as a simple problem in spherical trigonometry. A FORTRAN subroutine is provided to perform the necessary computations.

  12. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to the boiler backhead in the cab. If boiler backhead is lagged, the lagging and jacket shall be cut away...

  13. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to the boiler backhead in the cab. If boiler backhead is lagged, the lagging and jacket shall be cut away...

  14. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to the boiler backhead in the cab. If boiler backhead is lagged, the lagging and jacket shall be cut away...

  15. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to the boiler backhead in the cab. If boiler backhead is lagged, the lagging and jacket shall be cut away...

  16. 49 CFR 230.46 - Badge plates.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Boilers and Appurtenances Steam Gauges § 230.46 Badge plates. A metal badge plate showing the allowed steam pressure shall be attached to the boiler backhead in the cab. If boiler backhead is lagged, the lagging and jacket shall be cut away...

  17. Layered Plating Specimens For Mechanical Tests

    NASA Technical Reports Server (NTRS)

    Thompson, Linda B.; Flowers, Cecil E.

    1991-01-01

    Layered specimens readily made in standard sizes for tensile and other tests of mechanical properties. Standard specimen of metal ordinarily difficult to plate to standard grip thickness or diameter made by augmentation with easier-to-plate material followed by machining to standard size and shape.

  18. Pre-Plated Cell Lines for ADMETox Applications in the Pharmaceutical Industry.

    PubMed

    Torres, Francisco M; Sáfár, Zsolt; Vázquez-Sánchez, Maria A; Kurunczi, Anita; Kis, Emese; Magnan, Rémi; Jani, Márton; Nicolás, Josep Oriol; Krajcsi, Péter

    2015-08-06

    Membrane transporters significantly modulate membrane permeability of endobiotics and xenobiotics, such as bile acids and drugs, respectively. Various in vitro methods have been established for both ATP-binding cassette (ABC) transporters to examine cellular efflux and uptake, and for solute carriers (SLC) to examine cellular uptake of substrates. Cell-based systems are the models of choice to test drug-transporter interactions as well as drug-drug interactions for research and regulatory purposes, albeit, for low passive permeability substrates of ABC transporters, vesicular uptake assays are also recommended. Commercially available pre-plated cells (e.g., immortalized or transfected) offer a useful alternative to in-house cell culture. Three main methods are known to manufacture pre-plated cultures: regular culture medium with vacuum seal, cryopreserved delivery, and the solid shipping media technology. The regular culture medium and the solid shipping media technologies provide ready-to-use models for end users. Models expressing a broad selection of transporters are available in pre-plated formats for absorption, distribution, metabolism, excretion, and toxicity (ADMETox) studies. Conversely, the application and utility of pre-plated cultures coupled with personal experiences have not been extensively covered in published research papers or reviews, despite availability and significant use of pre-plated products in the pharmaceutical industry. In this overview, we will briefly describe: 1) in vitro tools commonly used for ADMETox testing; 2) methods employed in manufacturing, shipment and preparation of pre-plated cell lines; 3) cell-membrane barrier models currently available in pre-plated format to reproduce passage restriction of physiological barriers to certain compounds; and 4) recommended pre-plated cell lines overexpressing uptake transporters for ADMETox applications.

  19. Characteristics of liquid sheets formed by splash plate nozzles

    NASA Astrophysics Data System (ADS)

    Ahmed, M.; Amighi, A.; Ashgriz, N.; Tran, H. N.

    2008-01-01

    An experimental study was conducted to identify the effect of viscosity on the characteristics of liquid sheets formed by a splash plate nozzle. Various mixtures of corn syrup and water are used to obtain viscosities in the range 1-170 mPa.s. Four different splash plates with nozzle diameters of 0.5, 0.75, 1, and 2 mm, with a constant plate angle of 55° were tested. Liquid sheets formed under various operating conditions were directly visualized. The sheet atomization process for the range of parameters studied here is governed by two different mechanisms: Rayleigh-Plateau (R-P) and Rayleigh-Taylor (R-T) instabilities. R-P occurs at the rim and R-T occurs on the thin sheet. The rim instability can be laminar or turbulent, depending on the jet Reynolds number. The R-T instability of the sheet is observed at the outer edges of the radially spreading sheet, where the sheet is the thinnest. It can also occur inside the sheet, due to formation of holes and ruptures.

  20. Delaminations in composite plates under transverse static or impact loads

    SciTech Connect

    Finn, S.R.

    1991-01-01

    A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to transverse static or dynamic (impact) loads. The plate may be simply supported, clamped, or free along its edges. A failure model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were then implemented by a computer code (IMPACT-ST) which can be used to estimate the load at which damage initiates as well as the locations, shapes, and sizes of the delaminations. Test were also performed measuring the geometries of delaminations in Fiberite T300/976 graphite-epoxy, Fiberite IM7/977-2 graphite-toughened epoxy, and ICI APC-2 graphite-PEEK plates subjected to transverse static and impact loads. The data were compared to results of the model and good agreements were found between the measured and calculated delamination lengths and widths.

  1. Is There Really A North American Plate?

    NASA Astrophysics Data System (ADS)

    Krill, A.

    2011-12-01

    Lithospheric plates are typically identified from earthquake epicenters and evidence such as GPS movements. But no evidence indicates a plate boundary between the North American and South American Plates. Some plate maps show them separated by a transform boundary, but it is only a fracture zone. Other maps show an "undefined plate boundary" or put no boundary between these two plates (check Google images). Early plate maps showed a single large American Plate, quite narrow east of the Caribbean Plate (Le Pichon 1968, Morgan 1968). The North and South American Plates became established by the leading textbook Earth (Press & Siever 1974). On their map, from a Scientific American article by John Dewey (1972), these new plates were separated by an "uncertain plate boundary." The reasons for postulating a North American Plate were probably more psychological than geological. Each of the other continents of the world had its own plate, and North American geologists naturally wanted theirs. Similarly, European geographers used to view Europe as its own continent. A single large plate should again be hypothesized. But the term American Plate would now be ambiguous ("Which plate, North or South?") Perhaps future textbook authors could call it the "Two-American Plate." Textbook authors ultimately decide such global-tectonic matters. I became aware of textbook authors' opinions and influence from my research into the history of Alfred Wegener's continental drift (see Fixists vs. Mobilists by Krill 2011). Leading textbook author Charles Schuchert realized that continental drift would abolish his cherished paleogeographic models of large east-west continents (Eria, Gondwana) and small oceans (Poseiden, Nereis). He and his junior coauthors conspired to keep drift evidence out of their textbooks, from the 1934-editions until the 1969-editions (Physical Geology by Longwell et al. 1969, Historical Geology by Dunbar & Waage 1969). Their textbooks ruled in America. Textbooks

  2. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Y.W.; Wiedermann, A.H.; Ockert, C.E.

    1983-08-26

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  3. Shock wave absorber having apertured plate

    DOEpatents

    Shin, Yong W.; Wiedermann, Arne H.; Ockert, Carl E.

    1985-01-01

    The shock or energy absorber disclosed herein utilizes an apertured plate maintained under the normal level of liquid flowing in a piping system and disposed between the normal liquid flow path and a cavity pressurized with a compressible gas. The degree of openness (or porosity) of the plate is between 0.01 and 0.60. The energy level of a shock wave travelling down the piping system thus is dissipated by some of the liquid being jetted through the apertured plate toward the cavity. The cavity is large compared to the quantity of liquid jetted through the apertured plate, so there is little change in its volume. The porosity of the apertured plate influences the percentage of energy absorbed.

  4. Cycloid kinematics of relative plate motion

    SciTech Connect

    Cronin, V.S.

    1987-11-01

    The trajectory of a point on one plate as observed from another plate is generally a complex curve and not a small circle around a single axis of relative motion, as is commonly assumed. The shape of the relative-motion path is given the general name spherical cycloid because of its morphological similarity to cycloid planetary trajectories described by early astronomers. The cycloid relative-motion model predicts that the following phenomena occur during finite displacements: (1) the relative velocity and the curvature of the trajectory of a point on one plate relative to another plate varies systematically; (2) plates wobble relative to one another; and (3) the angle of convergence and/or divergence varies systematically along the length of any given transform fault. The small-circle relative-motion model, whereby transform faults have been considered lines of pure slip along which crust is conserved, is not generally valid for finite relative displacements.

  5. Volcanism in response to plate flexure.

    PubMed

    Hirano, Naoto; Takahashi, Eiichi; Yamamoto, Junji; Abe, Natsue; Ingle, Stephanie P; Kaneoka, Ichiro; Hirata, Takafumi; Kimura, Jun-Ichi; Ishii, Teruaki; Ogawa, Yujiro; Machida, Shiki; Suyehiro, Kiyoshi

    2006-09-01

    Volcanism on Earth is known to occur in three tectonic settings: divergent plate boundaries (such as mid-ocean ridges), convergent plate boundaries (such as island arcs), and hot spots. We report volcanism on the 135 million-year-old Pacific Plate not belonging to any of these categories. Small alkalic volcanoes form from small percent melts and originate in the asthenosphere, as implied by their trace element geochemistry and noble gas isotopic compositions. We propose that these small volcanoes erupt along lithospheric fractures in response to plate flexure during subduction. Minor extents of asthenospheric melting and the volcanoes' tectonic alignment and age progression in the direction opposite to that of plate motion provide evidence for the presence of a small percent melt in the asthenosphere. PMID:16873612

  6. Pyramidal approach to license plate segmentation

    NASA Astrophysics Data System (ADS)

    Postolache, Alexandru; Trecat, Jacques C.

    1996-07-01

    Car identification is a goal in traffic control, transport planning, travel time measurement, managing parking lot traffic and so on. Most car identification algorithms contain a standalone plate segmentation process followed by a plate contents reading. A pyramidal algorithm for license plate segmentation, looking for textured regions, has been developed on a PC based system running Unix. It can be used directly in applications not requiring real time. When input images are relatively small, real-time performance is in fact accomplished by the algorithm. When using large images, porting the algorithm to special digital signal processors can easily lead to preserving real-time performance. Experimental results, for stationary and moving cars in outdoor scenes, showed high accuracy and high scores in detecting the plate. The algorithm also deals with cases where many character strings are present in the image, and not only the one corresponding to the plate. This is done by the means of a constrained texture regions classification.

  7. Alps, Carpathians and Dinarides-Hellenides: about plates, micro-plates and delaminated crustal blocks

    NASA Astrophysics Data System (ADS)

    Schmid, Stefan

    2014-05-01

    thickened crust ripped of the African plate, invaded the northern part of this oceanic embayment, virtually floating on asthenospheric mantle. The presently still surviving semi-detached Vrancea slab in Romania manifests of the combined effect of roll back and delamination of mantle lithosphere. On the other hand Tisza-Dacia, another crustal block formerly ripped off the European plate and forming a single entity since mid-Cretaceous times, also at least partly floating on asthenospheric mantle, invaded the Carpathian embayment from the south. Thereby the Tisza-Dacia crustal block underwent clockwise rotation by as much as 90° due to the corner effect of the Moesian platform firmly attached to Europe since mid-Cretaceous times (Ustaszewski et al. 2008). In the Dinaric-Aegean realm collision occurred much earlier than in the Alps and the Carpathians, i.e. at around the Cretaceous-Cenozoic boundary, provided that one accepts that there is yet no convincing evidence for the existence of a second "Pindos oceanic domain" closing later, i.e. in Eocene times. However, in spite of early collision, the old subduction zone that consumed the northern branch of Neotethys (Meliata-Vardar) since at least mid-Cretaceous times persisted in the eastern Hellenides (but not in the Dinarides) until now, penetrating the transition zone all the way to a depth of some 1500km (Bijwaard et al. 1998). Continued subduction of mantle lithosphere in the Aegean since 60 Ma was concomitant with complete delamination of lithospheric mantle and lower crust from non-subducted or re-exhumed high pressure crustal flakes of largely continental derivation that were piled up to form the subsequently extended Hellenic orogen (Jolivet & Brun 2010). At around 25 Ma when the southern branch of Neotethys (the present-day Eastern Mediterranean ocean) entered this subduction zone, massive extension and core complex formation in the upper plate combined with an acceleration of south-directed hinge retreat of the lower

  8. Parallel Plate System for Collecting Data Used to Determine Viscosity

    NASA Technical Reports Server (NTRS)

    Kaukler, William (Inventor); Ethridge, Edwin C. (Inventor)

    2013-01-01

    A parallel-plate system collects data used to determine viscosity. A first plate is coupled to a translator so that the first plate can be moved along a first direction. A second plate has a pendulum device coupled thereto such that the second plate is suspended above and parallel to the first plate. The pendulum device constrains movement of the second plate to a second direction that is aligned with the first direction and is substantially parallel thereto. A force measuring device is coupled to the second plate for measuring force along the second direction caused by movement of the second plate.

  9. Investigation on mechanical properties of contemporary metallic bone plates: towards the development of composite bone plates.

    PubMed

    Hoque, M E; Zainal, N H; Syarif, J

    2008-07-01

    This study aims at investigating the mechanical properties of the contemporary metallic bone plates determining the effect of their length, width and thickness on the properties and compares with the composite bone plates. Three-points bending test was performed over the stainless steel plates of different length, width and thickness. The test results showed that different plates had different mechanical properties. However, the properties are still much higher than that of particular bones intended to be treated. Therefore, the reported findings strongly encourage developing composite bone plates with biocompatible polymers/fibers that would have modulated properties according to the requirements.

  10. Vibration of plates using plate characteristic functions obtained by reduction of partial differential equation

    NASA Astrophysics Data System (ADS)

    Bhat, R. B.; Mundkur, G.

    1993-02-01

    Vibration of rectangular plates is studied using a set of plate characteristic functions generated by reduction of the plate partial differential equation, and exactly solving the resulting ordinary differential equation. The plate characteristic functions are used as deflection shape functions in the Rayleigh-Ritz method to obtain the natural frequencies. Because the solution is exact in one direction, the results fall in between the exact values and those obtained with the straight forward Rayleigh-Ritz method, where the complete deflection shape is assumed initially. Results are provided for rectangular plates with combinations of clamped, simply supported and free edge conditions.

  11. Suramin inhibits helicase activity of NS3 protein of dengue virus in a fluorescence-based high throughput assay format.

    PubMed

    Basavannacharya, Chandrakala; Vasudevan, Subhash G

    2014-10-24

    Dengue fever is a major health concern worldwide. The virus encoded non-structural protein 3 (NS3) is a multifunctional protein endowed with protease, helicase, nucleoside triphosphatase (NTPase) and RNA 5' triphosphatase (RTPase) activities. Helicase activity of NS3 catalyzes the unwinding of double stranded polynucleotides by utilizing the energy released from ATP hydrolysis. As this activity is essential for replication, NS3 helicase represents an attractive drug target for developing a dengue antiviral drug. Here, we report fluorescence based molecular beacon helicase assay using a duplex RNA substrate that contains a fluorophore on the 5' end and a quencher on the 3' end of one of the strands. The assay was optimized with respect to several parameters and adapted to 384-well high-throughput screening format, with an average Z' factor of 0.65. Assay validation with a small diverse set library of 1600 compounds identified, suramin as a significant inhibitor of the helicase activity of NS3. Helicase activity deficient NS3 K199A was used in a counter-screen to identify compounds interfering with the assay. Suramin inhibited DENV (dengue virus) NS3 helicase activity with a Ki of 0.75±0.03μM as a non-competitive inhibitor. The molecular beacon helicase assay together with the counter screen and suramin as a tool compound can be used to identify novel inhibitors of DENV helicase.

  12. The jubilee of plate tectonics

    NASA Astrophysics Data System (ADS)

    Glen, William; Frankel, Henry

    What should one expect at a birthday gathering for an idea that suffered disdain from birth, but was later transformed overnight into the ruling global theory of the Earth sciences? Tom Hilde and Richard Carlson (Texas A&M University, College Station, Tex.), under the auspices of the Texas A&M Geodynamics Research Institute, with the cooperation of the National Aeronautics and Space Administration (NASA) , the Inter-Union Commission on the Lithosphere, and the U.S. Geodynamics Committee, convened an unprecedented gathering of the makers of Earth science's modern revolution and a large number of their foremost disciples at Texas A&M April 22- 24 , 1987.Those who missed the show will have to read for weeks to learn of the panoply of profound new developments across the broad front of research bearing on plate tectonics, but those with an interest in their own intellectual genealogy will not be able to recapture the sense of historic moment that pervaded Rudder Tower Conference Center as many of the old revolutionaries opened windows on the past. Of the 20 key participants or originators who were invited to speak, all but four sent abstracts. Pleased and surprised by this strong response, the convenors found themselves in the rather difficult position of having to limit the number of talks by nonoriginators to 20. The unique assembly also provided the first opportunity to video interviews with more than a dozen of the originators.

  13. Spirit's Tracks around 'Home Plate'

    NASA Technical Reports Server (NTRS)

    2006-01-01

    [figure removed for brevity, see original site] Annotated Version

    This portion of an image acquired by the Mars Reconnaissance Orbiter's High Resolution Imaging Science Experiment camera shows the Spirit rover's winter campaign site. The rover is visible. So is the 'Low Ridge' feature where Spirit was parked with an 11-degree northerly tilt to maximize sunlight on the solar panels during the southern winter season. Tracks made by Spirit on the way to 'Home Plate' and to and from 'Tyrone,' an area of light-toned soils exposed by rover wheel motions, are also evident. The original image is catalogued as PSP_001513_1655_red and was taken Sept. 29, 2006.

    NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, is the prime contractor for the project and built the spacecraft. The High Resolution Imaging Science Experiment is operated by the University of Arizona, Tucson, and the instrument was built by Ball Aerospace and Technology Corp., Boulder, Colo.

  14. The Effects of the Flyer Plate's Radius of Curvature on the Performance of an Explosively Formed Projectile

    NASA Astrophysics Data System (ADS)

    Mulligan, Phillip; Baird, Jason; Hoffman, Joshua

    2011-06-01

    An explosively formed projectile (EFP) is known for its ability to penetrate vehicle armor effectively. Understanding how an EFP's physical parameters affect its performance is crucial to development of an armor capable of defeating such devices. The present study uses two flyer plate radii of curvature to identify the experimental effects the flyer plate's radius of curvature has on the measured projectile velocity, depth of penetration, and projectile shape of an EFP. The Gurney equation is an algebraic relationship for estimating the velocity imparted to a metal plate in contact with detonating explosives (1). In their attempts to calculate an EFP theoretical flyer plate velocity, the authors of this research used the open-faced-sandwich Gurney equation, whereby a semi-infinite slab of explosive is in intimate contact with a semi-infinite metal flyer plate. This equation uses the flyer-weight to charge-weight ratio and the specific explosive kinetic energy to calculate the theoretical flyer plate velocity. Two EFP designs that have two different flyer plate radii of curvature, but the same physical parameters and the same flyer-weight to charge-weight ratio should theoretically have the same velocity. Test results indicate the flyer plate's radius of curvature does not affect the projectile's velocity and that using a flat flyer plate negatively affects projectile penetration and formation.

  15. Digital Archive of UkrVO: first results of MAO NASU Solar System Bodies photographic plate processing

    NASA Astrophysics Data System (ADS)

    Ivanov, G.; Pakuliak, L.; Shatokhina, S.; Yizhakevych, E.; Kazantseva, L.; Andruk, V.

    The digitizing and processing of photographic plates with the images of the outer planets and their satellites from the archive collections of MAO NASU and AO of Kiev university included into the UkrVO Joint Digital Archive (JDA) have been made. Plates were obtained in the last half of the 20th century. The digitizing of JDA archive plates and inclusion of plate preview images into GPA database has been under way, using two models of flatbed scanners: Microtek ScanMaker 9800XL TMA and Epson Expression 10000XL. The database with metadata of plates is allocated on the computational resources of MAO NASU (http://gua.db.ukr-vo.org). Plates have been scanned at 16-bits grey dynamic range, with a resolution of 1200-1600 dpi, and saved in TIFF format. Linear dimensions of images are up to 13 thousand pixels (for plates 30.30 cm). The astrometric and photometric calibration procedures have been done in the LINUX-MIDASROMAFOT environment and Tycho-2 as reference with the image processing procedure specially developed for digitized images of huge linear dimensions on the basis of the image inherent traits. First results of digitized plate processing give the rms errors of 10 and 20 mas for RA, DEC respectively. (O-C) for plates with Pluto in comparison to JPL PLU021.DE405 has been derived of 140(RA) and 270(DEC) mas.

  16. Cretaceous to present kinematics of the Indian, African and Seychelles plates

    NASA Astrophysics Data System (ADS)

    Eagles, Graeme; Hoang, Ha H.

    2014-01-01

    An iterative inverse model of seafloor spreading data from the Mascarene and Madagascar basins and the flanks of the Carlsberg Ridge describes a continuous history of Indian-African Plate divergence since 84 Ma. Visual-fit modelling of conjugate magnetic anomaly data from near the Seychelles platform and Laxmi Ridge documents rapid rotation of a Seychelles Plate about a nearby Euler pole in Palaeocene times. As the Euler pole migrated during this rotation, the Amirante Trench on the western side of the plate accommodated first convergence and later divergence with the African Plate. The unusual present-day morphology of the Amirante Trench and neighbouring Amirante Banks can be related to crustal thickening by thrusting and folding during the convergent phase and the subsequent development of a spreading centre with a median valley during the divergent phase. The model fits FZ trends in the north Arabian and east Somali basins, suggesting that they formed in India-Africa Plate divergence. Seafloor fabric in and between the basins shows that they initially hosted a segmented spreading ridge that accommodated slow plate divergence until 71-69 Ma, and that upon arrival of the Deccan-Réunion plume and an increase to faster plate divergence rates in the period 69-65 Ma, segments of the ridge lengthened and propagated. Ridge propagation into the Indian continental margin led first to the formation of the Laxmi Basin, which accompanied extensive volcanism onshore at the Deccan Traps and offshore at the Saurashtra High and Somnath Ridge. A second propagation episode initiated the ancestral Carlsberg Ridge at which Seychelles-India and India-Africa Plate motions were accommodated. With the completion of this propagation, the plate boundaries in the Mascarene Basin were abandoned. Seafloor spreading between this time and the present has been accommodated solely at the Carlsberg Ridge.

  17. Collaborative study comparing the spiral plate and aerobic plate count methods.

    PubMed

    Gilchrist, J E; Donnelly, C B; Peeler, J T; Campbell, J E

    1977-07-01

    The spiral plate count method is a semiautomated plating technique that greatly reduces manpower and material costs normally associated with the pour plating technique. In this collaborative study, 8 laboratories compared the spiral and pour plating techniques, using 4 samples each of 3 products: frozen pumpkin pie, frozen chicken pot pie, and shampoo. The results show that 10 of the 12 comparisons of means of the pour and spiral methods were not significantly different; 2 values were significant at alpha = 0.01. Overall, the components of variance were less than that of the current milk standard, and the replicate per cent coefficient of variation was satisfactory. This study indicates that the spiral plate method is an acceptable alternative to the pour plate method; the spiral plate method has been adopted as official first action.

  18. On the Origin of Plate Tectonics

    NASA Astrophysics Data System (ADS)

    Bercovici, D.

    2014-12-01

    The emergence of plate tectonics was Earth's defining moment. How and when platetectonics started is shrouded in mystery because of the paucity of observations in theArchean as well the challenge of understanding how plates are generated. The damage theoryof lithospheric weakening by grain-reduction provides a physical framework for plategeneration. This model builds on grain-scale processes to elucidate planetary-scaletectonics, and is consistent with lab and field observations of polycrystalline rocks andlithospheric shear zones. The grain-damage model accounts for the evolution of damage andhealing (by grain growth) at various planetary conditions, hence predicts plate boundaryformation and longevity, and how they depend on surface environment. For example, the onset of prototectonics is predicted to require clement conditions tokeep healing from erasing weak zones; conversely, cool conditions possibly requiredtectonics to draw down primordial CO2. Thus whether tectonics preceded a cool climate (andwater) or vice versa is immaterial as they likely needed each other or neither wouldexist. Sparse evidence that prototectonics co-initiated with liquid water hints at thelink between tectonics, water and surface conditions. The establishment of wide-spread plate tectonics started between >4Ga and 2.7Ga, and mayhave taken over a billion years to develop. Under Earth-like conditions, combininggrain-damage with intermittent Archean protosubduction produces persistent weak zones thataccumulate to yield well developed plates within 1Gyrs. In contrast, Venus' hottersurface conditions promotes healing and prohibits weak zone accumulation, which explainswhy plate tectonics failed to spread on our sister planet. Damage and weak-zone inheritance may also influence plate evolution and reorganization inthe modern era. Changes in plate direction, such as reflected in the Emperor-Hawaiianbend, leave weak zones misaligned with plate motion, causing oblique plate boundaries

  19. Reducing chromium losses from a chromium plating bath. 1987 summer intern report. Project conducted at New Dimension Plating, Hutchinson, Minnesota

    SciTech Connect

    Achman, D.

    1987-12-31

    The company employs about forty people and operates for one or two eight hour shifts with an average of 315 racks of chrome plating per eight hour day. They plate a variety of metals including copper, nickel, gold, brass and chromium. Chromium is the major metal plated and is usually the last step in plating cycle. Most parts are copper plated and then nickel plated in preparation for chrome plating. The main difference between New Dimension Plating and other plating shops is the variety of parts plated. As New Dimension Plating is a job shop, a wide range of parts such as motorcycle accessories, stove parts, and custom items are metal finished. The plating lines are manual, meaning employees dip the racks into the tanks by hand. This fact along with the fact that parts vary greatly in size and shape accounts for the significant drag-out on the chromium plating line.

  20. IDENTIFICATION OF SALMONELLA-POSITIVE FECAL SAMPLES USING A 96-WELL MICROCULTURE PLATE TECHNIQUE (RX METHOD)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conventional Salmonella isolation involves multiple sample transfers to culture media performed by an experienced microbiologist. The modified semi-solid RV and XLT (RX) Plate method, a modification of the RX tube format designed by Gailey et al. (2004), consolidates pre-enrichment (buffered pepton...

  1. Flat Plate Solar Array Project: Proceedings of the 20th Project Integration Meeting

    NASA Technical Reports Server (NTRS)

    Mcdonald, R. R.

    1982-01-01

    Progress made by the Flat-Plate Solar Array Project during the period November 1981 to April 1982 is reported. Project analysis and integration, technology research in silicon material, large-area silicon sheet and environmental isolation, cell and module formation, engineering sciences, and module performance and failure analysis are covered.

  2. Relations between plate kinematics, slab geometry and overriding plate deformation in subduction zones: insights from statistical observations and laboratory modelling

    NASA Astrophysics Data System (ADS)

    Heuret, A.; Funiciello, F.; Faccenna, C.; Lallemand, S.

    2005-12-01

    3-D laboratory models have been performed in order to investigate the way plates kinematics (subducting and overriding plate absolute motions and the resulting plate convergence rate) influences the geometry of the slab and the overriding plate deformation in subduction zones. In the experiments a viscous plate of silicone (subducting plate) is pushed beneath another plate, which is itself pushed toward or pulled away from the trench (overriding plate), and sinks into a viscous layer of glucose syrup (upper mantle). The subducting and overriding plate velocities explored the variability field of natural subduction plates kinematics. The overriding plate motion exerts a primary role in the control of slab geometries and overriding plate deformation rates. The experiments have revealed two different subduction behaviours: (Style I) the overriding plate moves toward the trench and shortens at high rates, the slab is flat and deflected when reaching the bottom of the box in a forward direction; (Style II) the overriding plates moves away from the trench and shortens at low rates the slab is steep and deflected on the box bottom in a backward direction. To a lesser extent, increasing subducting plate motion is associated to increasing slab dips and overriding plate shortening. Slab geometry and overriding plate deformation are less sensitive to the overall plate convergence rate. These laboratory models behaviours are consistent with statistical analysis performed on natural subduction zones, and enlighten the first order control exerted by the overriding plate absolute motion, on the geometry adopted by the slab and the way the overriding plate deforms.

  3. Global Plate Driving Forces at 50Ma

    NASA Astrophysics Data System (ADS)

    Butterworth, N. P.; Quevedo, L. E.; Müller, R. D.

    2011-12-01

    We apply a novel workflow utilising the BEM-Earth geodynamic software to analyse the global coupled plate-mantle dynamics at 50 Ma. A subduction history model based on kinematic data going as far back as 80 Ma was developed using the GPlates software. Advection of the plates into the mantle takes into account the absolute plate motions and lithospheric thickness derived from its age to produce an estimated density heterogeneity initial model condition in the upper mantle. The resulting global model consists of regions of a mantle viscosity and density structure that is post-processed to ensure smooth non-overlapping 3D surfaces. BEM-Earth is then free to evolve the model toward the 50 Ma solution. The evolution of the model is driven by self-consistent buoyancy driven mantle dynamics. We use the model velocity output to quantify changes in forces driving the plates before and after 50 Ma. We analyse the rapid change in plate motion of India, Africa and plates in the Pacific Ocean basin by considering slab-pull, ridge-push and mantle drag/suction forces that naturally result from such top-down driven mantle flow. We compare the results with plate kinematic reconstructions and other geological observations.

  4. Scaling of energy absorbing composite plates

    NASA Technical Reports Server (NTRS)

    Jackson, Karen; Morton, John; Traffanstedt, Catherine; Boitnott, Richard

    1992-01-01

    The energy absorption response and crushing characteristics of geometrically scaled graphite-Kevlar epoxy composite plates were investigated. Three different trigger mechanisms including chamfer, notch, and steeple geometries were incorporated into the plate specimens to initiate crushing. Sustained crushing was achieved with a simple test fixture which provided lateral support to prevent global buckling. Values of specific sustained crushing stress (SSCS) were obtained which were comparable to values reported for tube specimens from previously published data. Two sizes of hybrid plates were fabricated; a baseline or model plate, and a full-scale plate with in-plane dimensions scaled by a factor of two. The thickness dimension of the full-scale plates was increased using two different techniques; the ply-level method in which each ply orientation in the baseline laminate stacking sequence is doubled, and the sublaminate technique in which the baseline laminate stacking sequence is repeated as a group. Results indicated that the SSCS is independent of trigger mechanism geometry. However, a reduction in the SSCS of 10-25 percent was observed for the full-scale plates as compared with the baseline specimens, indicating a scaling effect in the crushing response.

  5. Electrochemical Machining of Metal Plates

    SciTech Connect

    Cooper, J F; Evans, M C

    2005-03-04

    Electrochemical machining (ECM) with concentrated sodium chlorate electrolyte was used to rapidly cut a circular groove (13 cm diameter, 0.2 cm wide) through a 0.15 cm thick sheet of steel--thus opening a 5-inch porthole in as little as 10 minutes. The most favorable operating conditions were: T = 22 C; chlorate concentration 600 g NaClO{sub 3}/liter-solution; electric power of 100 A at 10 V; and flow of 0.5 l/s at a pressure drop of 10 kPa (1.5 psi). The porthole may be removed entirely by electrochemical means, or the electrochemical dissolution may continue until only thin membrane remains that is subsequently cut with a utility knife. An array of thermocouples was used to track temperature in the flowing solution and in the trough being machined; the maximum increase in temperature in the trough was 5 C over that of the flowing electrolyte which increased in temperature by 19 C because of power dissipation. ECM is shown feasible for rapid perforation of plates of ferrous and non-ferrous metals using portable equipment and commercial batteries. The technique can be extended to cut perforations of arbitrary shape through non-planar surfaces using a deformable ring cathode. Analysis of the power requirements for electrolyte flow and ECM indicate a total system weight of less than 45 kg (100 lb) using a commercial NiMH battery. The technique is recommended for reduction to practice and demonstration on full scale as an engineering prototype.

  6. Screen test for cadmium and nickel plates

    NASA Technical Reports Server (NTRS)

    Phan, Angie H.; Zimmerman, Albert H.

    1994-01-01

    A new procedure is described which was recently developed to quantify loading uniformity of nickel and cadmium plates and to screen finished electrodes prior to cell assembly. The technique utilizes the initial solubility rates of the active material in a standard chemical deloading solution at fixed conditions. The method can provide a reproducible indication of plate loading uniformity in situations where high surface loading limits the free flow of deloading solution into the internal porosity of the sinter plate. A preliminary study indicates that 'good' cell performance is associated with higher deloading rates.

  7. Laminated anisotropic reinforced plastic plates and shells

    NASA Technical Reports Server (NTRS)

    Korolev, V. I.

    1981-01-01

    Basic technical theories and engineering calculation equations for anisotropic plates and shells made of rigid reinforced plastics, mainly laminated fiberglass, are presented and discussed. Solutions are given for many problems of design of structural plates and shells, including curved sections and tanks, as well as two chapters on selection of the optimum materials, are given. Accounting for interlayer shearing and transverse separation, which are new engineering properties, are discussed. Application of the results obtained to thin three ply plates and shells wth a light elastic filler is presented and discussed.

  8. Modeling Residual Stresses in Ceramic Plates

    NASA Astrophysics Data System (ADS)

    Cantavella, V.; Moreno, A.; Mezquita, A.; Reig, Y.

    2008-02-01

    The generation of residual stresses during cooling of layered ceramic plates has been modeled. Each plate comprises a body and two thin layers (engobe and glaze). The model takes into account two types of stresses: thermal stresses, resulting from temperature gradients inside the plate during cooling, and the stresses produced by the mismatch of the coefficient of thermal expansion (CTE) of the layers. The body has been simulated using a linear viscoelastic constitutive equation. The engobe and the glaze layer have been considered as elastic solids below a certain temperature (setting temperature: Ta). Above Ta these two layers have no mechanical influence on the body.

  9. Bi-coolant flat plate solar collector

    NASA Astrophysics Data System (ADS)

    Chon, W. Y.; Green, L. L.

    The feasibility study of a flat plate solar collector which heats air and water concurrently or separately was carried out. Air flows above the collector absorber plate, while water flows in tubes soldered or brazed beneath the plate. The collector efficiencies computed for the flow of both air and water are compared with those for the flow of a single coolant. The results show that the bi-coolant collector efficiency computed for the entire year in Buffalo, New York is higher than the single-coolant collector efficiency, although the efficiency of the water collector is higher during the warmer months.

  10. Elastic buckling of tapered circular plates

    NASA Astrophysics Data System (ADS)

    Wang, C. M.; Hong, G. M.; Tan, T. J.

    1995-06-01

    This paper is concerned with the elastic buckling of tapered circular plates. The study is prompted by the fact that results hitherto available are restricted to a narrow range of taper parameters and are somewhat different from each other. For the buckling analysis, a simple and yet accurate numerical method is presented. It is based on the shooting method and the Rayleigh-Ritz approach. Comprehensive generic buckling results of circular plates with linearly and parabolically varying thicknesses are generated. Comparison studies of the buckling results showed that some of the existing results were erroneous. Optimal values of taper parameters for such tapered plates are also given.

  11. Vibration and buckling of super elliptical plates

    NASA Astrophysics Data System (ADS)

    Wang, C. M.; Wang, L.; Liew, K. M.

    1994-03-01

    This paper is concerned with the vibration and buckling of a new class of plates, the periphery shape of which is defined by a super elliptical function. Such a plate shape has practical applications, as the advantageous curved corners help to diffuse stress concentrations. The loading considered for the buckling problem is that of in-plane uniform pressure along the periphery. Accurate frequency and buckling factors are tabulated for such plates with either simply supported or clamped edges. The solutions are obtained using the pb - 2 Rayleigh-Ritz method.

  12. Seismic anisotropy above a subducting plate

    SciTech Connect

    Shih, X.R.; Meyer, R.P. ); Schneider, J.F. )

    1991-08-01

    Shear-wave splitting observed in northeastern Colombia has provided evidence of seismic anisotropy in a shear zone immediately above a subducting plate. In an upper mantle composed mainly of olivine (57%) and orthopyroxene (17%), the splitting can be interpreted by wave propagation in an anisotropic medium of orthorhombic symmetry that results from alignment of these intrinsically anisotropic minerals. The mechanism of alignment is most likely the shearing associated with the subduction, aided by fluids migrating from the subducting plate when the plate exceeds 100 km in depth.

  13. Strongly coupled stress waves in heterogeneous plates.

    NASA Technical Reports Server (NTRS)

    Wang, A. S. D.; Chou, P. C.; Rose, J. L.

    1972-01-01

    Consideration of coupled stress waves generated by an impulsive load applied at one end of a semiinfinite plate. For the field equations governing the one-dimensional coupled waves a hyperbolic system of equations is obtained in which a strong coupling in the second derivatives exists. The method of characteristics described by Chou and Mortimer (1967) is extended to cover the case of strong coupling, and a study is made of the transient stress waves in a semiinfinite plate subjected to an initial step input. Coupled discontinuity fronts are found to propagate at different velocities. The normal plate stress and the bending moment at different time regimes are illustrated by graphs.

  14. Improvements in Cold-Plate Fabrication

    NASA Technical Reports Server (NTRS)

    Zaffetti, Mark A.; Taddey, Edmund P.; Laurin, Michael B.; Chabebe, Natalia

    2012-01-01

    Five improvements are reported in cold-plate fabrication. This cold plate is part of a thermal control system designed to serve on space missions. The first improvement is the merging of the end sheets of the cold plate with the face sheets of the structural honeycomb panel. The cold plate, which can be a brazed assembly, uses the honeycomb face sheet as its end sheet. Thus, when the honeycomb panel is fabricated, the face sheet that is used is already part of the cold plate. In addition to reducing weight, costs, and steps, the main benefit of this invention is that it creates a more structurally sound assembly. The second improvement involves incorporation of the header into the closure bar to pass the fluid to a lower layer. Conventional designs have used a separate header, which increases the geometry of the system. The improvement reduces the geometry, thus allowing the cold plate to fit into smaller area. The third improvement eliminates the need of hose, tube, or manifold to supply the cooling fluid externally. The external arrangement can be easily damaged and is vulnerable to leakage. The new arrangement incorporates an internal fluid transfer tube. This allows the fluid to pass from one cold plate to the other without any exposed external features. The fourth improvement eliminates separate fabrication of cold plate(s) and structural members followed by a process of attaching them to each other. Here, the structural member is made of material that can be brazed just as that of the cold plate. Now the structural member and the cold plate can be brazed at the same time, creating a monolithic unit, and thus a more structurally sound assembly. Finally, the fifth improvement is the elimination of an additional welding step that can damage the braze joints. A tube section, which is usually welded on after the braze process, is replaced with a more structurally sound configuration that can be brazed at the same time as the rest of the cold plate.

  15. Modeling Residual Stresses in Ceramic Plates

    SciTech Connect

    Cantavella, V.; Moreno, A.; Mezquita, A.; Reig, Y.

    2008-02-15

    The generation of residual stresses during cooling of layered ceramic plates has been modeled. Each plate comprises a body and two thin layers (engobe and glaze). The model takes into account two types of stresses: thermal stresses, resulting from temperature gradients inside the plate during cooling, and the stresses produced by the mismatch of the coefficient of thermal expansion (CTE) of the layers. The body has been simulated using a linear viscoelastic constitutive equation. The engobe and the glaze layer have been considered as elastic solids below a certain temperature (setting temperature: T{sub a}). Above T{sub a} these two layers have no mechanical influence on the body.

  16. Electromagnetic semitransparent δ-function plate: Casimir interaction energy between parallel infinitesimally thin plates

    NASA Astrophysics Data System (ADS)

    Parashar, Prachi; Milton, Kimball A.; Shajesh, K. V.; Schaden, M.

    2012-10-01

    We derive boundary conditions for electromagnetic fields on a δ-function plate. The optical properties of such a plate are shown to necessarily be anisotropic in that they only depend on the transverse properties of the plate. We unambiguously obtain the boundary conditions for a perfectly conducting δ-function plate in the limit of infinite dielectric response. We show that a material does not “optically vanish” in the thin-plate limit. The thin-plate limit of a plasma slab of thickness d with plasma frequency ωp2=ζp/d reduces to a δ-function plate for frequencies (ω=iζ) satisfying ζd≪ζpd≪1. We show that the Casimir interaction energy between two parallel perfectly conducting δ-function plates is the same as that for parallel perfectly conducting slabs. Similarly, we show that the interaction energy between an atom and a perfect electrically conducting δ-function plate is the usual Casimir-Polder energy, which is verified by considering the thin-plate limit of dielectric slabs. The “thick” and “thin” boundary conditions considered by Bordag are found to be identical in the sense that they lead to the same electromagnetic fields.

  17. Thermo-mechanical buckling analysis of FGM plate using generalized plate theory

    NASA Astrophysics Data System (ADS)

    Sharma, Kanishk; Kumar, Dinesh; Gite, Anil

    2016-05-01

    This paper investigates the thermo-mechanical buckling behavior of simply-supported FGM plate under the framework of generalized plate theory (GPT), which includes classical plate theory (CPT), first order shear deformation theory (FSDT) and higher order shear deformation theory (HSDT) as special cases. The governing equations for FGM plate under thermal and mechanical loading conditions are derived from the principle of virtual displacements and Navier-type solution is assumed for simply supported boundary condition. The efficiency and applicability of presented methodology is illustrated by considering various examples of thermal and mechanical buckling of FGM plates. The closed form solutions in the form of critical thermal and mechanical buckling loads, predicted by CPT, FSDT and HSDT are compared for different side-to-thickness of FGM plate. Subsequently, the effect of material gradation profile on critical buckling parameters is examined by evaluating the buckling response for a range of power law indexes. The effect of geometrical parameters on mechanical buckling of FGM plate under uni-axial and bi-axial loading conditions are also illustrated by calculating the critical load for various values of slenderness ratios. Furthermore a comparative analysis of critical thermal buckling loads of FGM plate for different temperature profiles is also presented. It is identified that all plate theories predicted approximately same critical buckling loads and critical buckling temperatures for thin FGM plate, however for thick FGM plates, CPT overestimates the critical buckling parameters. Moreover the critical buckling loads and critical buckling temperatures of FGM plate are found to be significantly lower than the corresponding homogenous isotropic ceramic plate (n=0).

  18. Compressive strength of damaged and repaired composite plates

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1992-01-01

    Tests were performed assessing the effectiveness of repair in restoring the mechanical properties of damaged, solid composite plates made of Fiberite T300/976 graphite-epoxy. Some (75%) or all (100%) of the damaged zone was cut out, and the plate was repaired by plugging and patching the hole. The effectiveness of the repair was evaluated by measuring the compressive strengths of undamaged plates, damaged plates with no cutout, damaged plates with a cutout, and plates that had been repaired.

  19. Biomechanical and biological aspects of defect treatment in fractures using helical plates.

    PubMed

    Perren, S M; Regazzoni, P; Fernandez, A A D

    2014-01-01

    The clinical case of figure 1 through figure 11 shows a series of impressive failures of plate fixation. The plates were repeatedly applied bridging a comminuted bone segment in a heavy patient. The biomechanical analysis elaborates why this happened and proposes an unconventional procedure to prevent this failure with a minimally invasive procedure. A plate bridging an open gap or a defect in a long bone diaphysis is exposed to full functional load. According to clinical observations such plate application often fails even without external load such as weight bearing. The plate risks to break through fatigue when exposed during a long time to cyclic loading. This type of failure has been observed even with broad plates as well in femoral as in tibiae. The first option to avoid such failure consists in protecting the plate by installing load sharing between plate and either bone or an additional implant. This reduces the load carried by the plate to a safe level. Load sharing with bone may be installed at surgery by establishing solid mechanical bridge between the two main fragments of the fractured bone. The optimal load sharing relies on a solid compressed contact between the main fragments. It can be established because the bone is able to take a large load which results in optimal protection of the plate. In the case of an extended comminuted bone segment it may be very difficult, traumatizing and inefficient to reconstruct the bone. In the present case it was impossible to establish load sharing through the bone. The second option protecting the plate is provided by callus bridging of the gap or defect. The formation of a solid callus bridge takes time but the fatigue failure of the plate also takes time. Therefore, the callus bridge may prevent a late fatigue failure. The surgeon may select one of several options: - Replacing the lack of bone support using a second plate which immediately alleviates plate loading. The drawback of application of a second

  20. 30 CFR 18.11 - Approval plate.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... extension(s) of approval were based. (d) A completely assembled approved machine with an integral dust collector shall bear an approval plate indicating that the requirements of part 33 of this chapter...

  1. Coloured Rings Produced on Transparent Plates

    ERIC Educational Resources Information Center

    Suhr, Wilfried; Schlichting, H. Joachim

    2007-01-01

    Beautiful colored interference rings can be produced by using transparent plates such as window glass. A simple model explains this effect, which was described by Newton but has almost been forgotten. (Contains 11 figures.)

  2. Optimal stabilization of indefinite plate buckling problems

    NASA Astrophysics Data System (ADS)

    Chase, J. Geoffrey; Bhashyam, Srinivas

    2001-08-01

    Indefinite plate buckling problems arise when the applied load case results in buckling loads which are not all of the same sign. Examples include the important cases of shear buckling and general combinations of tensile and compressive in-plane edge loads. Optimal controllers which actively stabilize these general, indefinite plate buckling problems, by transforming them into a system of definite plate buckling problems, are presented. Important features of this approach include the ability to select the designed closed loop critical buckling load, and to pre-determine what load cases a given controller will stabilize when the exact load combination varies or is unknown. This last result enables the control designer to know exactly, by design, what load combinations will be stabilized. A numerical example is presented where the controllers developed are employed to stabilize multiple, definite and indefinite buckling modes for laminated composite plates similar to aircraft wing skins.

  3. Vibro-acoustic analysis of composite plates

    NASA Astrophysics Data System (ADS)

    Sarigül, A. S.; Karagözlü, E.

    2014-03-01

    Vibro-acoustic analysis plays a vital role on the design of aircrafts, spacecrafts, land vehicles and ships produced from thin plates backed by closed cavities, with regard to human health and living comfort. For this type of structures, it is required a coupled solution that takes into account structural-acoustic interaction which is crucial for sensitive solutions. In this study, coupled vibro-acoustic analyses of plates produced from composite materials have been performed by using finite element analysis software. The study has been carried out for E-glass/Epoxy, Kevlar/Epoxy and Carbon/Epoxy plates with different ply angles and numbers of ply. The effects of composite material, ply orientation and number of layer on coupled vibro-acoustic characteristics of plates have been analysed for various combinations. The analysis results have been statistically examined and assessed.

  4. Characterization of Tri-lab Tantalum Plate.

    SciTech Connect

    Buchheit, Thomas E.; Cerreta, Ellen K.; Deibler, Lisa Anne; Chen, Shu-Rong; Michael, Joseph R.

    2014-09-01

    This report provides a detailed characterization Tri-lab Tantalum (Ta) plate jointly purchased from HCStark Inc. by Sandia, Los Alamos and Lawrence Livermore National Laboratories. Data in this report was compiled from series of material and properties characterization experiments carried out at Sandia (SNL) and Los Alamos (LANL) Laboratories through a leveraged effort funded by the C2 campaign. Results include microstructure characterization detailing the crystallographic texture of the material and an increase in grain size near the end of the rolled plate. Mechanical properties evaluations include, compression cylinder, sub-scale tension specimen, micohardness and instrumented indentation testing. The plate was found to have vastly superior uniformity when compare with previously characterized wrought Ta material. Small but measurable variations in microstructure and properties were noted at the end, and at the top and bottom edges of the plate.

  5. The Continental Plates are Getting Thicker.

    ERIC Educational Resources Information Center

    Kerr, Richard A.

    1986-01-01

    Reviews seismological studies that provide evidence of the existence of continental roots beneath the continents. Suggests, that through the collisions of plate tectonics, continents stabilized part of the mobile mantle rock beneath them to form deep roots. (ML)

  6. Stop motion microphotography of laser driven plates

    SciTech Connect

    Frank, A.M.; Trott, W.M.

    1994-09-01

    Laser driven plates have been used for several years for high velocity shock wave and impact studies. Recent questions about the integrity and ablation rates of these plates coupled with an improved capability for microscopic stop motion photography led to this study. For these experiments, the plates were aluminum, coated on the ends of optical fibers. A high power laser pulse in the fiber ionizes the aluminum at the fiber/coating interface. The plasma thus created accelerates the remaining aluminum to high velocities, several kilometers per second. We defined {open_quotes}thick{close_quotes} or {open_quotes}thin{close_quotes} coatings as those where a flying plate (flyer) was launched vs. the material being completely ionized. Here we were specifically interested in the thick/thin boundary to develop data for the numerical models attempting to predict flyer behavior.

  7. Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).

    PubMed

    Lemloh, Marie-Louise; Marin, Frédéric; Herbst, Frédéric; Plasseraud, Laurent; Schweikert, Michael; Baier, Johannes; Bill, Joachim; Brümmer, Franz

    2013-02-01

    In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, energy-dispersive X-ray spectroscopy, FTIR and X-ray diffraction. Our investigations revealed an organic mesh-like structure that guides the formation of new alveolar plates like a template and the role of vesicles transporting inorganic material. We further demonstrated that the inorganic part of the alveolar plates is composed out of amorphous calcium carbonate. For stabilization of the amorphous phase, the alveolar vesicles, the organic fraction and the element phosphorus may play a role. PMID:23228488

  8. A feasibility study on laser rapid forming of a complete titanium denture base plate.

    PubMed

    Wu, Jiang; Gao, Bo; Tan, Hua; Chen, Jing; Tang, Chak-Yin; Tsui, Chi-Pong

    2010-05-01

    This work attempted to integrate the technologies of computer-aided design and computer-aided manufacture (CAD/CAM) and laser rapid forming (LRF) for the fabrication of the titanium plate of a complete denture. By the combination of laser scan and reverse engineering software, the standard triangulation language (STL)-formatted denture base plate was finally designed and sliced into a sequence of numerical controlled codes. The titanium (Ti) complete denture plate was finally built, layer-by-layer, on the LRF system. To evaluate the quality of fit, a virtual adaptation test that measured and compared the profiles of the laser free formed denture plate and those of the edentulous plaster cast had been conducted, and the mean deviation was found to be 0.34 mm. After traditional dental finishing techniques, a complete denture with a Ti base plate was then made and judged to be acceptable. The CAD/CAM/LRF system is a potential candidate and a new platform for the design and manufacture of custom-made Ti denture plates and restorations. PMID:18716825

  9. Simulations of structural and dynamic anisotropy in nano-confined water between parallel graphite plates.

    PubMed

    Mosaddeghi, Hamid; Alavi, Saman; Kowsari, M H; Najafi, Bijan

    2012-11-14

    We use molecular dynamics simulations to study the structure, dynamics, and transport properties of nano-confined water between parallel graphite plates with separation distances (H) from 7 to 20 Å at different water densities with an emphasis on anisotropies generated by confinement. The behavior of the confined water phase is compared to non-confined bulk water under similar pressure and temperature conditions. Our simulations show anisotropic structure and dynamics of the confined water phase in directions parallel and perpendicular to the graphite plate. The magnitude of these anisotropies depends on the slit width H. Confined water shows "solid-like" structure and slow dynamics for the water layers near the plates. The mean square displacements (MSDs) and velocity autocorrelation functions (VACFs) for directions parallel and perpendicular to the graphite plates are calculated. By increasing the confinement distance from H = 7 Å to H = 20 Å, the MSD increases and the behavior of the VACF indicates that the confined water changes from solid-like to liquid-like dynamics. If the initial density of the water phase is set up using geometric criteria (i.e., distance between the graphite plates), large pressures (in the order of ~10 katm), and large pressure anisotropies are established within the water. By decreasing the density of the water between the confined plates to about 0.9 g cm(-3), bubble formation and restructuring of the water layers are observed.

  10. Friction behavior of network-structured CNT coating on pure titanium plate

    NASA Astrophysics Data System (ADS)

    Umeda, Junko; Fugetsu, Bunshi; Nishida, Erika; Miyaji, Hirofumi; Kondoh, Katsuyoshi

    2015-12-01

    Friction behavior of the network-structured CNTs coated pure Ti plate was evaluated by ball-on-disk wear test using SUS304 ball specimen under dry condition. The friction coefficient was significantly low and stable compared to the as-received Ti plate with no coating film. CNTs coating film had two important roles; self-lubrication and bearing effects to reduce the friction coefficient and carbon solid-solution hardening to improve the abrasive wear property of Ti plate. The annealing treatment at higher temperature (1123 K) was more effective to reduce the friction coefficient than that at lower temperature (973 K) because the Ti plate surface was uniformly covered with CNTs film even after sliding wear test. This is due to TiC interlayer formation via a reaction between Ti plate and carbon elements originated from CNTs during annealing. As a result, a strong interface bonding between CNTs film and Ti plate surface was obtained by higher temperature annealing treatment, and obstructed the detachment of CNTs film during wear test.

  11. Theoretical analysis on pulsed microwave heating of pork meat supported on ceramic plate.

    PubMed

    Basak, Tanmay; Rao, Badri S

    2010-11-01

    Theoretical analysis has been carried out to study the role of ceramic plates (alumina and SiC) and pulsed microwave heating of pork meat (Pork Luncheon Roll (PLR) and White Pudding (WP)) samples. Spatial hot spots occur either at the center of the sample or at the outer face or at the face attached with alumina plate and application of pulsing minimizes formation of hot spots within meat samples. Pulsing of microwave is characterized by set point for temperature difference (ΔTS) and on-off constraints for temperature (T'). It is found that alumina plate with higher ΔTS and lower T' may be recommended for thick meat samples (both WP and PLR) whereas for thin meat samples, lower ΔTS with alumina plate/without plate may be preferred. It is also observed that SiC plate may be selectively used with ΔTS=20K for both the pork meats. The distributed microwave incidence is found to be effective due to lesser degree of thermal runaway in absence of pulsing for both meat samples.

  12. Simulations of structural and dynamic anisotropy in nano-confined water between parallel graphite plates

    NASA Astrophysics Data System (ADS)

    Mosaddeghi, Hamid; Alavi, Saman; Kowsari, M. H.; Najafi, Bijan

    2012-11-01

    We use molecular dynamics simulations to study the structure, dynamics, and transport properties of nano-confined water between parallel graphite plates with separation distances (H) from 7 to 20 Å at different water densities with an emphasis on anisotropies generated by confinement. The behavior of the confined water phase is compared to non-confined bulk water under similar pressure and temperature conditions. Our simulations show anisotropic structure and dynamics of the confined water phase in directions parallel and perpendicular to the graphite plate. The magnitude of these anisotropies depends on the slit width H. Confined water shows "solid-like" structure and slow dynamics for the water layers near the plates. The mean square displacements (MSDs) and velocity autocorrelation functions (VACFs) for directions parallel and perpendicular to the graphite plates are calculated. By increasing the confinement distance from H = 7 Å to H = 20 Å, the MSD increases and the behavior of the VACF indicates that the confined water changes from solid-like to liquid-like dynamics. If the initial density of the water phase is set up using geometric criteria (i.e., distance between the graphite plates), large pressures (in the order of ˜10 katm), and large pressure anisotropies are established within the water. By decreasing the density of the water between the confined plates to about 0.9 g cm-3, bubble formation and restructuring of the water layers are observed.

  13. Enumeration of waterborne Escherichia coli with petrifilm plates: comparison to standard methods.

    PubMed

    Vail, J H; Morgan, R; Merino, C R; Gonzales, F; Miller, R; Ram, J L

    2003-01-01

    Escherichia coli is often monitored in environmental waters as an indicator of the possible presence of human pathogens associated with feces. Petrifilm E. coli/coliform count plates (3M, Minneapolis, MN), previously validated for enumerating E. coli in food, were tested for monitoring E. coli in environmental water. Escherichia coli counts in environmental water samples enumerated with Petrifilm were significantly correlated (R > 0.9; slope = 0.9-1.0; p < 0.001) with counts obtained with three commonly used methods, mTEC (Becton Dickinson, Sparks, MD), m-ColiBlue (Hach, Loveland, CO), and Colilert-18/IDEXX Quanti-Tray 2000 (IDEXX, Westbrook, ME). Blue colonies on Petrifilm plates were most reliably identified as E. coli when accompanied by gas formation, as determined by characterization of the colonies on MacConkey agar plates (PML Microbiologicals, Mississauga, ON, Canada) and by polymerase chair reaction (PCR) with E. coli-specific primers. The main disadvantage of Petrifilm plates for environmental water testing is the small volume (1 mL per sample) that can be tested; however, the plates appear to be suitable for screening and locating sites that exceed criteria for total body and partial body contact. Simplicity of use and storage, reliability, and relatively low cost make Petrifilm plates suitable for volunteer-based and educational water quality monitoring applications, particularly when used as a preliminary screening method to identify problem sites.

  14. Genesis of amorphous calcium carbonate containing alveolar plates in the ciliate Coleps hirtus (Ciliophora, Prostomatea).

    PubMed

    Lemloh, Marie-Louise; Marin, Frédéric; Herbst, Frédéric; Plasseraud, Laurent; Schweikert, Michael; Baier, Johannes; Bill, Joachim; Brümmer, Franz

    2013-02-01

    In the protist world, the ciliate Coleps hirtus (phylum Ciliophora, class Prostomatea) synthesizes a peculiar biomineralized test made of alveolar plates, structures located within alveolar vesicles at the cell cortex. Alveolar plates are arranged by overlapping like an armor and they are thought to protect and/or stiffen the cell. Although their morphology is species-specific and of complex architecture, so far almost nothing is known about their genesis, their structure and their elemental and mineral composition. We investigated the genesis of new alveolar plates after cell division and examined cells and isolated alveolar plates by electron microscopy, energy-dispersive X-ray spectroscopy, FTIR and X-ray diffraction. Our investigations revealed an organic mesh-like structure that guides the formation of new alveolar plates like a template and the role of vesicles transporting inorganic material. We further demonstrated that the inorganic part of the alveolar plates is composed out of amorphous calcium carbonate. For stabilization of the amorphous phase, the alveolar vesicles, the organic fraction and the element phosphorus may play a role.

  15. Numerical Study on plumes and thermochemical piles in plate-mode convection

    NASA Astrophysics Data System (ADS)

    Stein, C.; Brannaschke, K.; Hansen, U.

    2010-12-01

    Plates and plumes are two important aspects of mantle convection that both have large impact on the structure and dynamics of the Earth's mantle. Tectonic plates shield the interior from effective cooling and the movement of plates and subduction processes affect the dynamics of the interior. Thermal plumes and thermochemical piles forming at the core-mantle boundary play a further role in the mixing and evolution of the mantle. We apply a 2D numerical code to investigate the structure and evolution of the mantle in thermal and thermochemical convection. In our model plates form in a self-consistent manner, so that we can study the effect of plate-mode convection. During periods of subduction, we observe the formation of plume clusters. In cases where we apply a strong pressure-dependent viscosity, we find a few, stable Superplumes. In thermochemical convection dense material is viscously trapped by the flow and piled up beneath plumes. We will here discuss the effect of plates on plumes and piles and compare the signals they leave at the surface and core-mantle boundary.

  16. Evolution of the Mariana Convergent Plate Margin System

    NASA Astrophysics Data System (ADS)

    Fryer, Patricia

    1996-02-01

    The Mariana convergent plate margin system of the western Pacific provides opportunities for studying the tectonic and geochemical processes of intraoceanic plate subduction without the added complexities of continental geology. The system's relative geologic simplicity and the well-exposed sections of lithosphere in each of its tectonic provinces permit in situ examination of processes critical to understanding subduction tectonics. Its general history provides analogs to ancient convergent margin terranes exposed on land and helps to explain the chemical mass balance in convergent plate margins. The Mariana convergent margin's long history of sequential formation of volcanic arcs and extensional back arc basins has created a series of volcanic arcs at the eastern edge of the Philippine Sea plate. The trenchward edge of the overriding plate has a relatively sparse sediment cover. Rocks outcropping on the trench's inner slope are typical of the early formed suprasubduction zone's lithosphere and have been subjected to various processes related to its tectonic history. Pervasive forearc faulting has exposed crust and upper mantle lithosphere. Many large serpentinized peridotite seamounts are within 100 km of the trench axis. From these we can learn the history of regional metamorphism and observe and sample active venting of slab fluids. Ocean drilling recovered suprasubduction zone lava sequences erupted since the Eocene that suggest that the forearc region remains volcanologically dynamic. Seismic studies and seafloor mapping show evidence of deformation throughout forearc evolution. Large portions of uplifted southern forearc are exposed at the larger islands. Active volcanoes at the base of the eastern boundary fault of the Mariana Trough vary in size and composition along strike and record regional differences in source composition. Their locations along strike of the arc are controlled in part by cross-arc structures that also facilitate formation of submarine

  17. A clamped rectangular plate containing a crack

    NASA Technical Reports Server (NTRS)

    Tang, R.; Erdogan, F.

    1985-01-01

    The general problem of a rectangular plate clamped along two parallel sides and containing a crack parallel to the clamps is considered. The problem is formulated in terms of a system of singular integral equations and the asymptotic behavior of the stress state near the corners is investigated. Numerical examples are considered for a clamped plate without a crack and with a centrally located crack, and the stress intensity factors and the stresses along the clamps are calculated.

  18. Improved Orifice Plate for Spray Gun

    NASA Technical Reports Server (NTRS)

    Cunningham, W.

    1986-01-01

    Erratic spray pattern of commercial spray gun changed to repeatable one by simple redesign of two parts. In modified spray gun orifice plate and polytetrafluoroethylene bushing redesigned to assure centering and alignment with nozzle. Such improvement useful in many industrial applications requiring repeatable spray patterns. Might include spraying of foam insulation, paint, other protective coatings, detergents, abrasives, adhesives, process chemicals, or fuels. Unmodified spray gun produces erratic spray because lateral misalignment between orifice plate and nozzle.

  19. Electrochemical cell and separator plate thereof

    DOEpatents

    Baker, Bernard S.; Dharia, Dilip J.

    1979-01-01

    A fuel cell includes a separator plate having first and second flow channels extending therethrough contiguously with an electrode and respectively in flow communication with the cell electrolyte and in flow isolation with respect to such electrolyte. In fuel cell system arrangement, the diverse type channels are suplied in common with process gas for thermal control purposes. The separator plate is readily formed by corrugation of integral sheet material.

  20. Tomography, the geoid and plate motions

    NASA Technical Reports Server (NTRS)

    Gable, Carl W.; O'Connell, Richard J.

    1991-01-01

    The dynamics of the earth's mantle and its relationship to mantle structure as revealed by seismic tomography, the geoid, and plate motions are discussed in a critical review of U.S. research from the period 1987-1990. Sections are devoted to plates and mantle convection; seismic anomalies, flow, and the geoid; subducted slabs and the 670-km discontinuity; the physical properties of the mantle; plumes; and computational and experimental modeling efforts. Also included is a comprehensive bibliography for the period.

  1. Lighting system with heat distribution face plate

    DOEpatents

    Arik, Mehmet; Weaver, Stanton Earl; Stecher, Thomas Elliot; Kuenzler, Glenn Howard; Wolfe, Jr., Charles Franklin; Li, Ri

    2013-09-10

    Lighting systems having a light source and a thermal management system are provided. The thermal management system includes synthetic jet devices, a heat sink and a heat distribution face plate. The synthetic jet devices are arranged in parallel to one and other and are configured to actively cool the lighting system. The heat distribution face plate is configured to radially transfer heat from the light source into the ambient air.

  2. Reconstructing Plate Motions on Europa with GPlates

    NASA Astrophysics Data System (ADS)

    Cutler, B. B.; Collins, G. C.; Prockter, L. M.; Patterson, G.; Kattenhorn, S. A.; Rhoden, A.; Cooper, C. M.

    2015-12-01

    Observations of past plate tectonic - like motions in Europa's icy lithosphere have been reported in previous studies. Quantifying the nature, age, and amount of plate motion is important for geophysical models of Europa's ice shell and for astrobiology, since subsumed pates could drive the flow of nutrients into the subsurface ocean. We have used GPlates software (Williams et al., GSA Today 2012) and a mosaic of regional-resolution Galileo SSI data from orbits E11, E15, E17, and E19 to make interactive reconstructions of both the Northern Falga region (60N, 220W) and the Castalia Macula region (0N, 225W). The advantage of this method is that plate motions are calculated on a sphere, while still maintaining the original Galileo image pieces in their proper geographic locations. Previous work on the Castalia Macula region (Patterson et al. J.Struct.Geol. 2006) and the adjacent Phaidra Linea region (Patterson and Ernst, LPSC 2011) found offsets along spreading boundaries, and then calculated the best fit finite rotations to close those offsets. Though this method is mathematically rigorous and gives a statistical goodness of fit, it is not easy to test multiple hypotheses for candidate piercing points or divisions of candidate plate boundaries. Through the interactive environment, we found that we could better account for observed offsets in this region by breaking it into 32 different plates. Patterson and Ernst broke the Phaidra region into 6 plates which exhibited nonrigid behavior, where our study breaks it into 16 rigid plates. The Northern Falga Regio area is interesting due to the potential for large amounts of subsumption of Europa's icy crust in this location. The previous reconstruction (Kattenhorn and Prockter, Nat.Geosci. 2014) was based on planar geometry, and we have replicated these results using a spherically-based reconstruction. We will present the plate maps and reconstructions for both of these regions, along with the best fit rotation poles.

  3. Method for plating with metal oxides

    DOEpatents

    Silver, G.L.; Martin, F.S.

    1994-08-23

    A method is disclosed of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate. 1 fig.

  4. Method for plating with metal oxides

    SciTech Connect

    Silver, Gary L.; Martin, Frank S.

    1994-08-23

    A method of plating hydrous metal oxides on at least one substrate, which method is indifferent to the electrochemical properties of the substrate, and comprises reacting metallic ions in aqueous solution with an appropriate oxidizing agent such as sodium hypochlorite or calcium sulfite with oxygen under suitable conditions of pH and concentration such that oxidation and precipitation of metal oxide are sufficiently slow to allow satisfactory plating of metal oxide on the substrate.

  5. Predicting Farnsworth Lantern success with a six-plate series of the Ishihara pseudoisochromatic plates.

    PubMed

    Hackman, R J

    2001-12-01

    The Farnsworth Lantern (FALANT) is the definitive color vision test for the Navy, Marine Corps, and Coast Guard. It is also the definitive color vision test for aviation personnel in the Army. Results from it are also accepted by the Federal Aviation Administration. For various reasons, it is desirable to have an alternative test that can predict success (i.e., a passing score) on the FALANT. In 1991, it was shown that a 14-plate series of Ishihara pseudoisochromatic plates could predict FALANT success provided the proper passing criteria was chosen. Interest has arisen regarding whether or not a 6-plate series of Ishihara plates can predict FALANT success. A study was undertaken to answer this question. It appears that a 6-plate series of Ishihara pseudoisochromatic plates can predict FALANT success.

  6. [Experimental study on carbon fiber reinforced plastic plate--analysis of stabilizing force required for plate].

    PubMed

    Iizuka, H

    1990-11-01

    Plates currently in use for the management of bone fracture made of metal present with various problems. We manufactured carbon fiber reinforced plastic (CFRP) plates from Pyrofil T/530 puriplegs overlaid at cross angles of +/- 10 degrees, +/- 20 degrees, and +/- 30 degrees for trial and carried out an experimental study on rabbit tibiofibular bones using 316L stainless steel plates of comparable shape and size as controls. The results indicate the influence of CFRP plate upon cortical bone was milder than that of stainless steel plate, with an adequate stabilizing force for the repair of fractured rabbit tibiofibular bones. CFRP has the advantages over metals of being virtually free from corrosion and fatigue, reasonably radiolucent and able to meet a wide range of mechanical requirements. This would make CFRP plate quite promising as a new devices of treating fracture of bones.

  7. Vibration of Rectangular Plates Using Plate Characteristic Functions as Shape Functions in the RAYLEIGH RITZ Method

    NASA Astrophysics Data System (ADS)

    Rajalingham, C.; Bhat, R. B.; Xistris, G. D.

    1996-06-01

    The plate characteristic functions are used to express the deflection shapes in the Rayleigh-Ritz method to study rectangular plate vibrations. Since the plate characteristic functions are reasonable approximations to the vibration modes, they are found to improve the convergence of vibration frequencies. These plate frequencies are used to check the accuracy of the Rayleigh frequencies associated with the plate characteristic function modes. Computations are carried out for each of the four mode categories of a clamped square plate. In each mode category, the first 30 natural frequencies are tabulated and the first nine mode diagrams are drawn. The results show that the choice of specific shape functions enhances the effectiveness of the Rayleigh-Ritz method.

  8. Abrupt plate accelerations shape rifted continental margins

    NASA Astrophysics Data System (ADS)

    Brune, Sascha; Williams, Simon E.; Butterworth, Nathaniel P.; Müller, R. Dietmar

    2016-08-01

    Rifted margins are formed by persistent stretching of continental lithosphere until breakup is achieved. It is well known that strain-rate-dependent processes control rift evolution, yet quantified extension histories of Earth’s major passive margins have become available only recently. Here we investigate rift kinematics globally by applying a new geotectonic analysis technique to revised global plate reconstructions. We find that rifted margins feature an initial, slow rift phase (less than ten millimetres per year, full rate) and that an abrupt increase of plate divergence introduces a fast rift phase. Plate acceleration takes place before continental rupture and considerable margin area is created during each phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The extension models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength–velocity feedback, which can be robustly inferred for diverse lithosphere configurations and rheologies. Our results explain differences between proximal and distal margin areas and demonstrate that abrupt plate acceleration during continental rifting is controlled by the nonlinear decay of the resistive rift strength force. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time.

  9. Abrupt plate accelerations shape rifted continental margins.

    PubMed

    Brune, Sascha; Williams, Simon E; Butterworth, Nathaniel P; Müller, R Dietmar

    2016-08-11

    Rifted margins are formed by persistent stretching of continental lithosphere until breakup is achieved. It is well known that strain-rate-dependent processes control rift evolution, yet quantified extension histories of Earth's major passive margins have become available only recently. Here we investigate rift kinematics globally by applying a new geotectonic analysis technique to revised global plate reconstructions. We find that rifted margins feature an initial, slow rift phase (less than ten millimetres per year, full rate) and that an abrupt increase of plate divergence introduces a fast rift phase. Plate acceleration takes place before continental rupture and considerable margin area is created during each phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The extension models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength--velocity feedback, which can be robustly inferred for diverse lithosphere configurations and rheologies. Our results explain differences between proximal and distal margin areas and demonstrate that abrupt plate acceleration during continental rifting is controlled by the nonlinear decay of the resistive rift strength force. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time.

  10. Modeling the hydrodynamics of Phloem sieve plates.

    PubMed

    Jensen, Kaare Hartvig; Mullendore, Daniel Leroy; Holbrook, Noel Michele; Bohr, Tomas; Knoblauch, Michael; Bruus, Henrik

    2012-01-01

    Sieve plates have an enormous impact on the efficiency of the phloem vascular system of plants, responsible for the distribution of photosynthetic products. These thin plates, which separate neighboring phloem cells, are perforated by a large number of tiny sieve pores and are believed to play a crucial role in protecting the phloem sap from intruding animals by blocking flow when the phloem cell is damaged. The resistance to the flow of viscous sap in the phloem vascular system is strongly affected by the presence of the sieve plates, but the hydrodynamics of the flow through them remains poorly understood. We propose a theoretical model for quantifying the effect of sieve plates on the phloem in the plant, thus unifying and improving previous work in the field. Numerical simulations of the flow in real and idealized phloem channels verify our model, and anatomical data from 19 plant species are investigated. We find that the sieve plate resistance is correlated to the cell lumen resistance, and that the sieve plate and the lumen contribute almost equally to the total hydraulic resistance of the phloem translocation pathway.

  11. The planar jet-plate oscillator

    NASA Astrophysics Data System (ADS)

    Arthurs, David; Ziada, Samir

    2011-01-01

    The aeroacoustic noise generated by a high speed, planar gas jet impinging on a flat plate is investigated experimentally. The jet used in this study is typical of those commonly found in industrial applications such as in various coating control and heat transfer processes. Normal jet impingement on the plate is found to generate strong acoustic tones over a wide range of impingement distances and jet velocities. The characteristics of these tones, as a function of the jet velocity and impingement distance, are quantified. Phase and amplitude measurements of the pressure fluctuations on the impingement plate indicate that the acoustic tones are generated by an antisymmetric instability mode of the jet oscillation. The effect of plate inclination in both the transverse and span-wise directions, with respect to the incident jet, is also studied. The jet-plate tone is found to be much more sensitive to changes in the span-wise plate inclination than to changes in the transverse inclination, but in both cases, a complete suppression of the tone is found to be possible.

  12. Optimization of a clamped plate silencer.

    PubMed

    Wang, Chunqi; Han, Jun; Huang, Lixi

    2007-02-01

    A previous theoretical study [L. Huang, J. Acoust. Soc. Am. 119, 2628-2638 (2006)] shows that, in a duct, a simply supported plate covering a side-branch rigid cavity can function effectively as a wave reflector over a broad range of low to medium frequencies. In this study, analytical formulation is extended to the boundary condition of clamped plate, which is easier to implement in practice. The theoretical model is tested experimentally using balsawood, which has a very high stiffness to mass ratio. The spectral peaks and shapes of the measured TL are in agreement with those calculated theoretically, attempts are also made to account for the considerable sound absorption in the rig. Further numerical studies based on the validated model show that, for a uniform plate, the optimal stopband is narrower and the lower band limit is worse than that of the simply supported configuration. However, a wave reflector using nonuniform, clamped plates with thinner ends out-performs the simply supported configuration in every aspect. Analyses show that the improvement is attributed to the increased acoustic radiation efficiency over the bulk length of the nonuniform plate, which behaves more like a rigid plate.

  13. Corrosion test cell for bipolar plates

    DOEpatents

    Weisbrod, Kirk R.

    2002-01-01

    A corrosion test cell for evaluating corrosion resistance in fuel cell bipolar plates is described. The cell has a transparent or translucent cell body having a pair of identical cell body members that seal against opposite sides of a bipolar plate. The cell includes an anode chamber and an cathode chamber, each on opposite sides of the plate. Each chamber contains a pair of mesh platinum current collectors and a catalyst layer pressed between current collectors and the plate. Each chamber is filled with an electrolyte solution that is replenished with fluid from a much larger electrolyte reservoir. The cell includes gas inlets to each chamber for hydrogen gas and air. As the gases flow into a chamber, they pass along the platinum mesh, through the catalyst layer, and to the bipolar plate. The gas exits the chamber through passageways that provide fluid communication between the anode and cathode chambers and the reservoir, and exits the test cell through an exit port in the reservoir. The flow of gas into the cell produces a constant flow of fresh electrolyte into each chamber. Openings in each cell body is member allow electrodes to enter the cell body and contact the electrolyte in the reservoir therein. During operation, while hydrogen gas is passed into one chamber and air into the other chamber, the cell resistance is measured, which is used to evaluate the corrosion properties of the bipolar plate.

  14. Data analysis for surface plate calibration

    SciTech Connect

    Burton, R.N.

    1997-08-01

    A surface plate is used to establish a reference plane used for making precision dimensional measurements. Ideally, the surface should be perfectly flat. Since it is impossible to create a perfectly flat surface, surface plate are calibrated to determine how much they deviate from a perfectly flat surface. Once a surface plate is calibrated, the user can determine if the plate is flat enough for use in a particular application. The currently accepted method of data analysis for surface plate calibration, the Moody method, does not give optimum results because of the arbitrary way in which the reference plane is chosen. The exact solution, wherein the reference plane is located in the optimum position, has been worked out and is given in a step by step procedure along with all of the necessary equations. The amount of calculation involved in a typical example proved to be prohibitive even for a computer, so an alternate solution using a least squares criterion for locating the reference plane was developed. Results were comparable with those from Moody`s method with values being smaller or greater depending on the shape of the plate.

  15. Vibration analysis of annular-like plates

    NASA Astrophysics Data System (ADS)

    Cheng, L.; Li, Y. Y.; Yam, L. H.

    2003-05-01

    The existence of eccentricity of the central hole for an annular plate results in a significant change in the natural frequencies and mode shapes of the structure. In this paper, the vibration analysis of annular-like plates is presented based on numerical and experimental approaches. Using the finite element analysis code Nastran, the effects of the eccentricity, hole size and boundary condition on vibration modes are investigated systematically through both global and local analyses. The results show that analyses for perfect symmetric conditions can still roughly predict the mode shapes of "recessive" modes of the plate with a slightly eccentric hole. They will, however, lead to erroneous results for "dominant" modes. In addition, the residual displacement mode shape is verified as an effective parameter for identifying damage occurring in plate-like structures. Experimental modal analysis on a clamped-free annular-like plate is performed, and the results obtained reveal good agreement with those obtained by numerical analysis. This study provides guidance on modal analysis, vibration measurement and damage detection of plate-like structures.

  16. Abrupt plate accelerations shape rifted continental margins.

    PubMed

    Brune, Sascha; Williams, Simon E; Butterworth, Nathaniel P; Müller, R Dietmar

    2016-08-11

    Rifted margins are formed by persistent stretching of continental lithosphere until breakup is achieved. It is well known that strain-rate-dependent processes control rift evolution, yet quantified extension histories of Earth's major passive margins have become available only recently. Here we investigate rift kinematics globally by applying a new geotectonic analysis technique to revised global plate reconstructions. We find that rifted margins feature an initial, slow rift phase (less than ten millimetres per year, full rate) and that an abrupt increase of plate divergence introduces a fast rift phase. Plate acceleration takes place before continental rupture and considerable margin area is created during each phase. We reproduce the rapid transition from slow to fast extension using analytical and numerical modelling with constant force boundary conditions. The extension models suggest that the two-phase velocity behaviour is caused by a rift-intrinsic strength--velocity feedback, which can be robustly inferred for diverse lithosphere configurations and rheologies. Our results explain differences between proximal and distal margin areas and demonstrate that abrupt plate acceleration during continental rifting is controlled by the nonlinear decay of the resistive rift strength force. This mechanism provides an explanation for several previously unexplained rapid absolute plate motion changes, offering new insights into the balance of plate driving forces through time. PMID:27437571

  17. Diffuse oceanic plate boundaries: Strain rates, vertically averaged rheology, and comparisons with narrow plate boundaries and stable plate interiors

    NASA Astrophysics Data System (ADS)

    Gordon, Richard G.

    Diffuse plate boundaries occur in both oceanic and continental lithosphere and cover ≈ 15% of Earth's solid surface. The fastest plate speeds accommodated across diffuse oceanic plate boundaries are ≈ 15 mm/yr. The smallest strain rates averaged across narrow plate boundaries are at least 102 times larger than the largest strain rates across diffuse oceanic plate boundaries and at least 102 times larger than those across stable plate interiors. The effective viscosity (ηeff) of the lithosphere is estimated from the ratio of vertically averaged shear stresses to strain rates for three tectonic settings: (i) oceanic transform fault zones, for which ηeff = 3 ×1016 to 5×1019 Pa s, comparable to estimates for the asthenosphere, (ii) diffuse oceanic plate boundaries, for which ηeff = 1×1023 to 6×l023 Pa s, ≈ 10 times larger than for diffuse continental plate boundaries, and (iii) stable plate interiors, for which ηeff = 1x1024 to 2×1027 Pa s. The rheology of oceanic lithosphere over times longer than earthquake cycles is modeled as a plastic layer overlying a layer that deforms by creeping flow [Martinod and Davy, 1992]. Oceanic lithosphere deforms when the yield strength of the upper lithosphere is exceeded. The vertically averaged rheology of deforming oceanic lithosphere can be approximated by a power-law fluid for which ɛ. ∝ (τs)n where ɛ. is the rate of shear strain and τs is the shear stress. If the ratio of the yield strength of the upper lithosphere to the force required to deform the lower lithosphere at a strain rate of 10-16 s-1 is varied from 10-2 to 102 , the calculated value of n varies from ≈3 to ≈300. The map-view aspect ratio of a deforming zone in a thin sheet of power-law fluid is proportional to n-½ [England et al., 1985]. A profile of displacement versus distance inferred from a seismic profile across the Central Indian Basin (India-Capricorn diffuse oceanic plate boundary), where the lithosphere is about 60-Myr old

  18. Vibration Analysis of Rectangular Isotropic Thick Plates Using Mindlin Plate Characteristic Functions

    NASA Astrophysics Data System (ADS)

    Lee, J. M.; Kim, K. C.

    1995-11-01

    An iterative Kantorovich method is presented for the vibration analysis of rectangular isotropic thick plates. Mindlin plate characteristic functions are derived in general forms by the Kantorovich method initially starting with Timoshenko beam functions consistent with the boundary conditions of the plate. Through numerical calculations of a natural pairs and dynamic responses of appropriate models, it has been confirmed that the method presented is superior to the Rayleigh-Ritz analysis or the FEM analysis in accuracy and computational efficiency.

  19. Current plate velocities relative to the hotspots incorporating the NUVEL-1 global plate motion model

    SciTech Connect

    Gripp, A.E.; Gordon, R.G. )

    1990-07-01

    NUVEL-1 is a new global model of current relative plate velocities which differ significantly from those of prior models. Here the authors incorporate NUVEL-1 into HS2-NUVEL1, a new global model of plate velocities relative to the hotspots. HS2-NUVEL1 was determined from the hotspot data and errors used by Minster and Jordan (1978) to determine AM1-2, which is their model of plate velocities relative to the hotspots. AM1-2 is consistent with Minster and Jordan's relative plate velocity model RM2. Here the authors compare HS2-NUVEL1 with AM1-2 and examine how their differences relate to differences between NUVEL-1 and RM2. HS2-NUVEL1 plate velocities relative to the hotspots are mainly similar to those of AM1-2. Minor differences between the two models include the following: (1) in HS2-NUVEL1 the speed of the partly continental, apparently non-subducting Indian plate is greater than that of the purely oceanic, subducting Nazca plate; (2) in places the direction of motion of the African, Antarctic, Arabian, Australian, Caribbean, Cocos, Eurasian, North American, and South American plates differs between models by more than 10{degree}; (3) in places the speed of the Australian, Caribbean, Cocos, Indian, and Nazca plates differs between models by more than 8 mm/yr. Although 27 of the 30 RM2 Euler vectors differ with 95% confidence from those of NUVEL-1, only the AM1-2 Arabia-hotspot and India-hotspot Euler vectors differ with 95% confidence from those of HS2-NUVEL1. Thus, substituting NUVEL-1 for RM2 in the inversion for plate velocities relative to the hotspots changes few Euler vectors significantly, presumably because the uncertainty in the velocity of a plate relative to the hotspots is much greater than the uncertainty in its velocity relative to other plates.

  20. Thermal stresses and deflections of cross-ply laminated plates using refined plate theories

    NASA Technical Reports Server (NTRS)

    Khdeir, A. A.; Reddy, J. N.

    1991-01-01

    Exact analytical solutions of refined plate theories are developed to study the thermal stresses and deflections of cross-ply rectangular plates. The state-space approach in conjunction with the Levy method is used to solve exactly the governing equations of the theories under various boundary conditions. Numerical results of the higher-order theory of Reddy for thermal stresses and deflections are compared with those obtained using the classical and first-order plate theories.

  1. Wavelength calibration of objective prism plates by transformation from direct plates

    NASA Astrophysics Data System (ADS)

    Tucholke, Hans-Joachim

    The zero points for galaxy redshift measurements from objective prison plates are obtained through the transformation of object positions from the corresponding direct plates. About 1000 G-stars per plate are employed. The transformation characteristics for three adjacent fields near the South Galactic Pole are presented. The mean residuals are about 5 microns, corresponding to a redshift error of about 700 km/s at z = 0.

  2. Barrel organ of plate tectonics - a new tool for outreach and education

    NASA Astrophysics Data System (ADS)

    Broz, Petr; Machek, Matěj; Šorm, Zdar

    2016-04-01

    Plate tectonics is the major geological concept to explain dynamics and structure of Earth's outer shell, the lithosphere. In the plate tectonic theory processes in the Earth lithosphere and its dynamics is driven by the relative motion and interaction of lithospheric plates. Geologically most active regions on Earth often correlate with the lithospheric plate boundaries. Thus for explaining the earth surface evolution, mountain building, volcanism and earthquake origin it is important to understand processes at the plate boundaries. However these processes associated with plate tectonics usually require significant period of time to take effects, therefore, their entire cycles cannot be directly observed in the nature by humans. This makes a challenge for scientists studying these processes, but also for teachers and popularizers trying to explain them to students and to the general public. Therefore, to overcome this problem, we developed a mechanical model of plate tectonics enabling demonstration of most important processes associated with plate tectonics in real time. The mechanical model is a wooden box, more specifically a special type of barrel organ, with hand painted backdrops in the front side. These backdrops are divided into several components representing geodynamic processes associated with plate tectonics, specifically convective currents occurring in the mantle, sea-floor spreading, a subduction of the oceanic crust under the continental crust, partial melting and volcanism associated with subduction, a formation of magmatic stripes, an ascent of mantle plume throughout the mantle, a volcanic activity associated with hot spots, and a formation and degradation of volcanic islands on moving lithospheric plate. All components are set in motion by a handle controlled by a human operator, and the scene is illuminated with colored lights controlled automatically by an electric device embedded in the box. Operation of the model may be seen on www

  3. An experimental investigation of decelerating flow about two-dimensional cambered plates

    SciTech Connect

    Sarpkaya, T.

    1987-10-30

    Impulsively-started uniform flow, decelerating at specified rates, about two-dimensional cambered plates with included angles of 120, 180, and 240 degrees has been investigated experimentally in a vertical water tunnel. The forces acting on the plates have been determined as a function of the relative displacement of the fluid at subcritical Reynolds numbers. The evolution of the vortices was visualized by means of various dyes and polystyrene beads. The variation of the drag coefficient with time is interpreted in terms of the formation, growth, and motion of vortices. 15 figs.

  4. The use of short carbon fibre reinforced thermoplastic plates for fracture fixation.

    PubMed

    Gillett, N; Brown, S A; Dumbleton, J H; Pool, R P

    1985-03-01

    Thermoplastic plates of Nylon 6-10 and Polybutylene terephthalate reinforced with 30% short randomly oriented carbon fibres were tested for internal fixation of canine femoral transverse midshaft fractures. The elastic modulus of the plates was one-half that of bone: however, ultimate strength and strain in bending were comparable to bone. The fractures healed with moderate callus formation which was completely remodelled by 8 to 12 wk post surgery. Although a moderate inflammatory reaction to occasional particulate debris was noted, the materials appeared to possess the proper elastic moduli to allow sufficient support for the healing fracture without protecting the remodelling process.

  5. Pre-treatment for molybdenum or molybdenum-rich alloy articles to be plated

    DOEpatents

    Wright, Ralph R.

    1980-01-01

    This invention is a method for etching a molybdenum or molybdenum-rich alloy surface to promote the formation of an adherent bond with a subsequently deposited metallic plating. In a typical application, the method is used as a pre-treatment for surfaces to be electrolessly plated with nickel. The pre-treatment comprises exposing the crystal boundaries of the surface by (a) anodizing the surface in acidic solution to form a continuous film of gray molybdenum oxide thereon and (b) removing the film.

  6. Delaminations in composite plates under transverse static or impact loads - A model

    NASA Technical Reports Server (NTRS)

    Finn, Scott R.; Springer, George S.

    1993-01-01

    A method is presented for calculating the locations, shapes, and sizes of delaminations which occur in a fiber reinforced composite plate subjected to transverse static or dynamic (impact) loads. The plate may be simply supported, clamped, or free along its edges. A model of the delamination formation was developed. This model was then coupled with a finite element analysis. The model and the finite element analysis were implemented by a computer code which can be used to estimate the load at which damage is initiated as well as the locations, shapes, and sizes of the delaminations.

  7. The present-day number of tectonic plates

    NASA Astrophysics Data System (ADS)

    Harrison, Christopher G. A.

    2016-03-01

    The number of tectonic plates on Earth described in the literature has expanded greatly since the start of the plate tectonic era, when only about a dozen plates were considered in global models of present-day plate motions. With new techniques of more accurate earthquake epicenter locations, modern ways of measuring ocean bathymetry using swath mapping, and the use of space based geodetic techniques, there has been a huge growth in the number of plates thought to exist. The study by Bird (2003) proposed 52 plates, many of which were delineated on the basis of earthquake locations. Because of the pattern of areas of these plates, he suggested that there should be more small plates than he could identify. In this paper, I gather together publications that have proposed a total of 107 new plates, giving 159 plates in all. The largest plate (Pacific) is about 20 % of the Earth's area or 104 Mm2, and the smallest of which (Plate number 5 from Hammond et al. 2011) is only 273 km2 in area. Sorting the plates by size allows us to investigate how size varies as a function of order. There are several changes of slope in the plots of plate number organized by size against plate size order which are discussed. The sizes of the largest seven plates is constrained by the area of the Earth. A middle set of 73 plates down to an area of 97,563 km2 (the Danakil plate at number 80, is the plate of median size) follows a fairly regular pattern of plate size as a function of plate number. For smaller plates, there is a break in the slope of the plate size/plate number plot and the next 32 plates follow a pattern of plate size proposed by the models of Koehn et al. (2008) down to an area of 11,638 km2 (West Mojave plate # 112). Smaller plates do not follow any regular pattern of area as a function of plate number, probably because we have not sampled enough of these very small plates to reveal any clear pattern.

  8. Caribbean plate tectonics from seismic tomography

    NASA Astrophysics Data System (ADS)

    Ten Brink, U. S.; Villasenor, A.

    2012-12-01

    New seismic tomography in the Caribbean shows close links between the geometry and dynamics of subducting slabs and the geology of the overriding plate. Unlike most oceanic plates, the Caribbean plate lacks identifiable seafloor magnetic anomalies and fracture zones. The plate's history has therefore been inferred primarily from land geology along the plate boundary, which is complicated by large-scale shear deformation, and from finite rotations of surrounding plates.We used more than 14 million arrival times from 300,000 earthquakes to identify P-wave velocity anomalies. We relate the anomalies to the geometry and dynamics of subducting slabs and to patterns of earthquake activity, volcanism, topographic relief, and tectonic deformation. For example, we detect two separate slabs belonging to the North and South American plates, respectively, which appear to be responsible for morphologic and tectonic differences between the arcs of the Northern (from Guadeloupe northward) and Southern (from Dominica southward) Lesser Antilles. Variations in earthquake activity between Haiti and the Dominican Republic can be explained by a change in slab geometry from an underplated slab beneath Haiti to a subducting slab under the Dominican Republic. A shallow tear in the slab may explain the anomalously deep Puerto Rico Trench and the frequent earthquake swarms there. The westward shift in volcanic activity in the Northern Lesser Antilles from the Miocene Limestone Caribbees to the present arc can be attributed to the limit on convective flow imposed by the 3-D geometry of the slab at depth. A thinned South America slab under the southern Lesser Antilles may result from traction imposed on the slab by a wide forearc wedge. Variations in tectonic deformation of northern South America could be related to the location of the Caribbean Large Igneous Province north of the Maracaibo Block.

  9. Motion of the Scotia sea plates

    USGS Publications Warehouse

    Thomas, C.; Livermore, R.; Pollitz, F.

    2003-01-01

    Earthquake data from the Scotia Arc to early 2002 are reviewed in the light of satellite gravity and other data in order to derive a model for the motion of plates in the Scotia Sea region. Events with magnitude ???5, which occurred on or near the boundaries of the Scotia and Sandwich plates, and for which Centroid Moment Tensor (CMT) solutions are available, are examined. The newer data fill some of the previous sampling gaps along the boundaries of the Scotia and Sandwich plates, and provide tighter constraints on relative motions. Variations in the width of the Brunhes anomaly on evenly spaced marine magnetic profiles over the East Scotia Ridge provide new estimates of Scotia-Sandwich plate spreading rates. Since there are no stable fracture zones in the east Scotia Sea, the mean azimuth of sea floor fabric mapped by sidescan is used to constrain the direction of spreading. 18 new rate estimates and four azimuths from the East Scotia Ridge are combined with 68 selected earthquake slip vectors from the boundaries of the Scotia Sea in a least-squares inversion for the best-fitting set of Euler poles and angular rotation rates describing the 'present-day' motions of the Scotia and Sandwich plates relative to South America and Antarctica. Our preferred model (TLP2003) gives poles that are similar to previous estimates, except for Scotia Plate motion with respect to South America, which is significantly different from earlier estimates; predicted rates of motion also differ slightly. Our results are much more robust than earlier work. We examine the implications of the model for motion and deformation along the various plate boundaries, with particular reference to the North and South Scotia Ridges, where rates are obtained by closure.

  10. Large Deflections of Elastic Rectangular Plates

    NASA Astrophysics Data System (ADS)

    Razdolsky, A. G.

    2015-11-01

    It is known that elastic large deflections of thin plates are governed by von Karman nonlinear equations. The analytical solution of these equations in the general case is unfeasible. Samuel Levy, in 1942, showed that large deflections of the rectangular plate can be expressed as a double series of sine-shaped harmonics (deflection harmonics). However, this method gave no way of creating the computer algorithm of solving the problem. The stress function expression taken in the Levy's method must be revised to find the approach that takes into account of all possible products of deflection coefficients. The algorithm of solving the problem for the rectangular plate with an arbitrary aspect ratio under the action of the lateral distributed load is reported in this paper. The approximation of the plate deflection is taken in the form of double series proposed by Samuel Levy. However, the expression for the stress function is presented in the form that incorporates products of deflection coefficients in the explicit form in distinction to the Levy's expression. The number of harmonics in the deflection expression may be arbitrary. The algorithm provides composing the system of governing cubic equations, which includes the deflection coefficients in the explicit form. Solving the equation system is based on using the principle of minimum potential energy. A method of the gradient descent is applied to find the equilibrium state of the plate as the minimum point of the potential energy. A computer program is developed on the basis of the present algorithm. Numerical examples carried out for the plate model with 16 deflection harmonics illustrate the potentialities of the program. The results of solving the examples are presented in the graphical form for the plates with a different aspect ratio and may be used under designing thin-walled elements of airplane and ship structures.

  11. 49 CFR 451.21 - Safety approval plate required.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 6 2012-10-01 2012-10-01 false Safety approval plate required. 451.21 Section 451... HOMELAND SECURITY SAFETY APPROVAL OF CARGO CONTAINERS TESTING AND APPROVAL OF CONTAINERS Safety Approval Plate § 451.21 Safety approval plate required. (a) The safety approval plate must be supplied by...

  12. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  13. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  14. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  15. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  16. 21 CFR 882.4030 - Skull plate anvil.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Skull plate anvil. 882.4030 Section 882.4030 Food... DEVICES NEUROLOGICAL DEVICES Neurological Surgical Devices § 882.4030 Skull plate anvil. (a) Identification. A skull plate anvil is a device used to form alterable skull plates in the proper shape to...

  17. Making More Efficient Use Of Battery-Plate Mass

    NASA Technical Reports Server (NTRS)

    Rowlette, John J.

    1990-01-01

    Improved active material for positive plate of lead/acid electric storage battery made with additional porosity to give electrolyte access to larger plate-surface area. 65 to 68 percent of active mass of plate used to generate electric current. Batteries with new plate material offer extremely long cycle life.

  18. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  19. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...

  20. 46 CFR 154.170 - Outer hull steel plating.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Outer hull steel plating. 154.170 Section 154.170... Structure § 154.170 Outer hull steel plating. (a) Except as required in paragraph (b) of this section, the outer hull steel plating, including the shell and deck plating must meet the material standards of...