Sample records for large atomic displacement

  1. Atomic displacements in ferroelectric trigonal and orthorhombic boracite structures

    USGS Publications Warehouse

    Dowty, E.; Clark, J.R.

    1972-01-01

    New crystal-structure refinements of Pca21 boracite, Mg3ClB7O13, and R??{lunate}c ericaite, Fe2.4Mg0.6ClB7O13, show that some boron and oxygen atoms are involved in the 'ferro' transitions as well as the metal and halogen atoms. The atomic displacements associated with the polarity changes are as large as 0.6A??. ?? 1972.

  2. Frictional behavior of large displacement experimental faults

    USGS Publications Warehouse

    Beeler, N.M.; Tullis, T.E.; Blanpied, M.L.; Weeks, J.D.

    1996-01-01

    The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (400 mm at 25??C and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after ???18 mm displacement, and an approximately constant strength is reached after a few tens of millimeters of sliding on initially bare surfaces. Simulated fault gouges show a large but systematic variation of friction, velocity dependence of friction, dilatancy, and degree of localization with displacement. At short displacement (<10 mm), simulated gouge is strong, velocity strengthening and changes in sliding velocity are accompanied by relatively large changes in dilatancy rate. With continued displacement, simulated gouges become progressively weaker and less velocity strengthening, the velocity dependence of dilatancy rate decreases, and deformation becomes localized into a narrow basal shear which at its most localized is observed to be velocity weakening. With subsequent displacement, the fault restrengthens, returns to velocity strengthening, or to velocity neutral, the velocity dependence of dilatancy rate becomes larger, and deformation becomes distributed. Correlation of friction, velocity dependence of friction and of dilatancy rate, and degree of localization at all displacements in simulated gouge suggest that all quantities are interrelated. The observations do not distinguish the independent variables but suggest that the degree of localization is controlled by the fault strength, not by the friction velocity dependence. The friction velocity dependence and velocity dependence of dilatancy rate can be used as qualitative measures of the degree of localization in simulated gouge, in agreement with previous studies. Theory equating the friction velocity dependence of simulated gouge to the sum of the friction velocity dependence of bare surfaces and the velocity dependence of dilatancy rate of simulated gouge fails to quantitatively account for the experimental observations.

  3. Atom interferometry using wave packets with constant spatial displacements

    E-print Network

    Su, Edward Joseph

    A standing-wave light-pulse sequence is demonstrated that places atoms into a superposition of wave packets with precisely controlled displacements that remain constant for times as long as 1 s. The separated wave packets ...

  4. Cross sections for atomic displacements in solids by fast positrons

    SciTech Connect

    Oen, Ordean S.

    1987-09-01

    The Mott series has been used to calculate the cross section for atomic displacements produced in elastic collisions between relativistic positrons and atomic nuclei. The Kinchin and Pease displacement model was used. Several elements spanning the atomic table were treated using positron energies ranging from threshold to several tens of MeV. The results are compared with previous calculations for relativistic electrons. It is found that for the same energy and atomic number the positron cross sections are always smaller (up to a factor of 5 or more). It is also found that the McKinley-Fesbach formula which is frequently used in radiation damage analysis is even less reliable for positrons than for electrons. 9 refs.

  5. Cross sections for atomic displacements in solids by fast positrons

    NASA Astrophysics Data System (ADS)

    Oen, Ordean S.

    1988-06-01

    The Mott series has been used to calculate the cross section for atomic displacements produced in elastic collisions between relativistic positrons and atomic nuclei. The Kinchin and Pease displacement model was used. Several elements spanning the atomic table were treated using positron energies ranging from threshold to several tens of MeV. The results are compared with previous calculations for relativistic electrons. It is found that for the same energy and atomic number the positron cross sections are always smaller (up to a factor of 5 or more). It is also found that the McKinley-Feshbach formula, which is frequently used in radiation damage analysis, is even less reliable for positrons than for electrons.

  6. Finding New Thermoelectric Compounds Using Crystallographic Data: Atomic Displacement Parameters

    SciTech Connect

    Chakoumakos, B.C.; Mandrus, D.G.; Sales, B.C.; Sharp, J.W.

    1999-08-29

    A new structure-property relationship is discussed which links atomic displacement parameters (ADPs) and the lattice thermal conductivity of clathrate-like compounds. For many clathrate-like compounds, in which one of the atom types is weakly bound and ''rattles'' within its atomic cage, room temperature ADP information can be used to estimate the room temperature lattice thermal conductivity, the vibration frequency of the ''rattler'', and the temperature dependence of the heat capacity. Neutron data and X-ray crystallography data, reported in the literature, are used to apply this analysis to several promising classes of thermoelectric materials.

  7. Functional Analysis of Large-scale DNA Strand Displacement Circuits

    E-print Network

    Hamadi, Yousseff

    Functional Analysis of Large-scale DNA Strand Displacement Circuits Boyan Yordanov, Christoph M prop- erties of large-scale DNA strand displacement (DSD) circuits based on Satisfiability Modulo Theories that enables us to prove the functional correctness of DNA circuit designs for arbitrary inputs

  8. On the Origin of Large Interstitial Clusters in Displacement Cascades

    SciTech Connect

    Andrew, Calder F [University of Liverpool; Barashev, Aleksandr [University of Liverpool; Bacon, David J [University of Liverpool; Osetskiy, Yury N [ORNL

    2010-01-01

    Displacement cascades with wide ranges of primary knock-on atom (PKA) energy and mass in iron were simulated using molecular dynamics. New visualisation techniques are introduced to show how the shock-front dynamics and internal structure of a cascade develop over time. These reveal that the nature of the final damage is determined early on in the cascade process. We define a zone (termed 'spaghetti') in which atoms are moved to new lattice sites and show how it is created by a supersonic shock-front expanding from the primary recoil event. A large cluster of self-interstitial atoms can form on the periphery of the spaghetti if a hypersonic recoil creates damage with a supersonic shock ahead of the main supersonic front. When the two fronts meet, the main one injects atoms into the low-density core of the other: these become interstitial atoms during the rapid recovery of the surrounding crystal. The hypersonic recoil occurs in less than 0.1 ps after the primary recoil and the interstitial cluster is formed before the onset of the thermal spike phase of the cascade process. The corresponding number of vacancies is then formed in the spaghetti core as the crystal cools, i.e. at times one to two orders of magnitude longer. By using the spaghetti zone to define cascade volume, the energy density of a cascade is shown to be almost independent of the PKA mass. This throws into doubt the conventional energy-density interpretation of an increased defect yield with increasing PKA mass in ion irradiation.

  9. On the origin of large interstitial clusters in displacement cascades

    Microsoft Academic Search

    Calder F Andrew; D. J. Bacon; A. V. Barashev; Yu. N. Osetsky

    2010-01-01

    Displacement cascades with wide ranges of primary knock-on atom (PKA) energy and mass in iron were simulated using molecular dynamics. New visualisation techniques are introduced to show how the shock-front dynamics and internal structure of a cascade develop over time. These reveal that the nature of the final damage is determined early on in the cascade process. We define a

  10. Large displacement vertical translational actuator based on piezoelectric thin films

    PubMed Central

    Qiu, Zhen; Pulskamp, Jeffrey S; Lin, Xianke; Rhee, Choong-Ho; Wang, Thomas; Polcawich, Ronald G; Oldham, Kenn

    2014-01-01

    A novel vertical translational microactuator based on thin-film piezoelectric actuation is presented, using a set of four compound bend-up/bend-down unimorphs to produce translational motion of a moving platform or stage. The actuation material is a chemical-solution deposited lead–zirconate–titanate (PZT) thin film. Prototype designs have shown as much as 120 ?m of static displacement, with 80–90 ?m displacements being typical, using four 920 ?m long by 70 ?m legs. Analytical models are presented that accurately describe nonlinear behavior in both static and dynamic operation of prototype stages when the dependence of piezoelectric coefficients on voltage is known. Resonance of the system is observed at a frequency of 200 Hz. The large displacement and high bandwidth of the actuators at low-voltage and low-power levels should make them useful to a variety of optical applications, including endoscopic microscopy. PMID:25506130

  11. Homologous Topology Optimization in Large Displacement and Buckling Problems

    Microsoft Academic Search

    Tatsuo Sekimoto; Hirohisa Noguchi

    2001-01-01

    The paper deals with homologous topology optimization of structures undergoing large deformations. The objective function is defined so that the load-displacement curve follows the prescribed trajectry, which shows a typical snap-through buckling. The geometrically non-linear behavior of the structures is modeled using the total-Lagrangian finite element formulation and the equilibrium is found using a Newton-Raphson iterative scheme. In order to

  12. SIFT flow for large-displacement object tracking.

    PubMed

    Zhang, Huanlong; Hu, Shiqiang; Zhang, Xiaoyu

    2014-09-20

    Traditional tracking methods place an emphasis on how to cope with the variations in target appearance effectively. However, when the motion displacement of the target between image frames becomes larger, these methods may be unstable. This paper presents a novel (to our knowledge) visual object tracking method. In this method, we first introduce scale-invariant feature transform (SIFT) flow into the tracking problem and develop a real-time motion prediction method to capture large displacement between consecutive image frames. Then we use belief propagation (BP) to convert the problem of finding maximum a posteriori probability (MAP) to globally minimizing an energy function to get the best matching pairs of points for producing good candidate regions of the target. And last, the refined point trajectories are obtained according to the bidirectional flow field consistency estimation and covariance region descriptor matching, which can update model states efficiently so as to achieve enhanced robustness for visual tracking. Compared with the state-of-art tracking methods, the experimental results demonstrate that the proposed algorithm shows favorable performance when the object undergoes large motion displacement between image frames. PMID:25322097

  13. Voltage-dependent Membrane Displacements Measured by Atomic Force Microscopy

    PubMed Central

    Mosbacher, J.; Langer, M.; Hörber, J.K.H.; Sachs, F.

    1998-01-01

    Cells use polar molecules in the membrane to sense changes in the transmembrane potential. The opening of voltage-gated ion channels and membrane bending due to the inverse flexoelectric effect are two examples of such electromechanical coupling. We have looked for membrane motions in an electric field using atomic (or scanning) force microscopy (AFM) with the intent of studying voltage-dependent conformational changes of ion channels. Voltage-clamped HEK293 cells were either untransfected controls or transfected with Shaker K+ channels. Using a ± 10-mV peak–peak AC carrier stimulus, untransfected cells moved 0.5–15 nm normal to the plane of the membrane. These movements tracked the voltage at frequencies >1 kHz with a phase lead of 60–120°, as expected of a displacement current. The movement was outward with depolarization, but the holding potential only weakly influenced the amplitude of the movement. In contrast, cells transfected with a noninactivating mutant of Shaker K+channels showed similar movements, but these were sensitive to the holding potential; decreasing with depolarization between ?80 and 0 mV. Searching for artifactual origins of these movements, we used open or sealed pipettes and AFM cantilever placements just above the cells. These results were negative, suggesting that the observed movements were produced by the cell membrane rather than by movement of the patch pipette, or by acoustic or electrical interactions of the membrane with the AFM tip. In control cells, the electrical motor may arise from the flexoelectric effect, where changes in potential induce changes in curvature. In transfected cells, it appears that channel-specific movements also occurred. These experiments demonstrate that the AFM may be able to exploit voltage-dependent movements as a source of contrast for imaging membrane components. The electrically induced motility will cause twitching during action potentials, and may have physiological consequences. PMID:9417135

  14. Large displacement of a static bending nanowire with surface effects

    NASA Astrophysics Data System (ADS)

    Liu, J. L.; Mei, Y.; Xia, R.; Zhu, W. L.

    2012-07-01

    Nanowires are widely used as building blocks of micro/nano devices, such as micro-sensors, probes, transistors and actuators in micro/nano-electro-mechanical systems (M/NEMS) and biotechnology. In this study, we investigated the large deformation behavior of a nanowire in consideration of its surface effects (surface elasticity and residual surface stress). For nanowires of large displacements with different boundary conditions, we established the governing equation set in combination with the residual surface stress and surface elasticity. Then a computer program of shooting method by using the commercial software MathCAD was developed to solve the boundary value problem numerically. Furthermore, the influences of surface effects on the large and infinitesimal deformation of the nanowires were quantitatively compared. These findings are beneficial to understanding the mechanism of the surface effects, and can also provide some inspirations to characterize the mechanical properties of nano-materials, and engineer new micro/nano-scaled devices.

  15. Three-dimensional anisotropic and inhomogeneous elastic media matrix analysis for small and large displacements

    Microsoft Academic Search

    J. H. Argyris

    1965-01-01

    A matrix displacement technique for analysing three-dimensional anisotropic and inhomogeneous elastic media is given for small and large displacements. The body is idealized by an assembly of finite tetrahedra. Using the novel device of ‘natural’ stresses, loads and elemental stiffness, concise expressions for stiffness of the complete system are set up. Hence small displacement solution is obtained. Extension to large

  16. The atomic anisotropic displacement tensor – completing the picture.

    PubMed

    Thorkildsen, Gunnar; Larsen, Helge B

    2015-07-01

    A simplified approach for calculating the equivalent isotropic displacement parameter is presented and the transformation property of the tensor representation U to point-group operations is analysed. Complete tables have been compiled for the restrictions imposed upon the tensor owing to the site symmetry associated with all special positions as listed in Hahn [(2011), International Tables for Crystallography, Vol. A, Space-group Symmetry, 5th revised ed. Chichester: John Wiley and Sons, Ltd]. PMID:26131902

  17. Note: Seesaw actuation of atomic force microscope probes for improved imaging bandwidth and displacement range

    SciTech Connect

    Torun, H. [Department of Electrical and Electronics Engineering, Bogazici University, Bebek, TR-34342 Istanbul (Turkey); Torello, D.; Degertekin, F. L. [G. W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332 (United States)

    2011-08-15

    The authors describe a method of actuation for atomic force microscope (AFM) probes to improve imaging speed and displacement range simultaneously. Unlike conventional piezoelectric tube actuation, the proposed method involves a lever and fulcrum ''seesaw'' like actuation mechanism that uses a small, fast piezoelectric transducer. The lever arm of the seesaw mechanism increases the apparent displacement range by an adjustable gain factor, overcoming the standard tradeoff between imaging speed and displacement range. Experimental characterization of a cantilever holder implementing the method is provided together with comparative line scans obtained with contact mode imaging. An imaging bandwidth of 30 kHz in air with the current setup was demonstrated.

  18. Large displacement formulation of a three-dimensional beam element with cross-sectional warping

    Microsoft Academic Search

    A. Dutta; D. W. White

    1992-01-01

    A displacement-based three-node beam element is formulated for analysis of the large displacement\\/large rotation response of curved structural components of rectangular cross-section, including the effects of cross-sectional warping due to torsion. Master-slave relationships are derived which facilitate the modeling of eccentric stiffeners in plate and shell structures. Efficient and explicit relationships are developed for transformation between relative through-thickness displacement and

  19. Mean square atomic displacements of LaFe4Sb12

    NASA Astrophysics Data System (ADS)

    Feldman, Joseph; Singh, David

    2005-03-01

    Calculations in the harmonic approximation of the mean square atomic displacements (MSDs) for the filled skutterudite, LaFe4Sb12, are discussed, where the first-principles based force constant model that we recently proposed for this material is employed.^1 The various values of MSDs at high temperatures are as expected, following the differences in coordination and short range force constants. The results are primarily compared with temperature dependent neutron diffraction measurements^2 of MSDs in La.75Fe3CoSb12. The differences between theory and experiment are interpreted in terms of static disorder contributions to the MSDs. In the case of the isotropic MSDs, the resulting static disorder contributions are comparable to the corresponding minimum values previously obtained^2 from a data analysis, and both the Sb and Fe values are small compared to the La value of 0.0045å^2. Nevertheless the anisotropy in the Sb static disorder is large on the basis of our analysis, and in the direction of the neighboring La site the Sb disorder parameter is comparable to the above value for La. Finally, the effect of La interactions on the Sb- and Fe-MSDs is discussed within the context of our model, as is an Einstein model, fitted to the calculated La MSD. 1. J.L. Feldman et al., Phys. Rev. B 68, 094301 (2003).2. B.C. Chakoumakos et al., Acta Cryst. B 55,341 (1999).

  20. Improved calculation of displacements per atom cross section in solids by gamma and electron irradiation

    NASA Astrophysics Data System (ADS)

    Piñera, Ibrahin; Cruz, Carlos M.; Leyva, Antonio; Abreu, Yamiel; Cabal, Ana E.; Espen, Piet Van; Remortel, Nick Van

    2014-11-01

    Several authors had estimated the displacements per atom cross sections under different approximations and models, including most of the main gamma- and electron-material interaction processes. These previous works used numerical approximation formulas which are applicable for limited energy ranges. We proposed the Monte Carlo assisted Classical Method (MCCM), which relates the established theories about atom displacements to the electron and positron secondary fluence distributions calculated from the Monte Carlo simulation. In this study the MCCM procedure is adapted in order to estimate the displacements per atom cross sections for gamma and electron irradiation. The results obtained through this procedure are compared with previous theoretical calculations. An improvement in about 10-90% for the gamma irradiation induced dpa cross section is observed in our results on regard to the previous evaluations for the studied incident energies. On the other hand, the dpa cross section values produced by irradiation with electrons are improved by our calculations in about 5-50% when compared with the theoretical approximations. When thin samples are irradiated with electrons, more precise results are obtained through the MCCM (in about 20-70%) with respect to the previous studies.

  1. Nonlinear large displacement and moderate rotational characteristics of composite beams incorporating transverse shear strain

    NASA Astrophysics Data System (ADS)

    Creaghan, Stephen G.

    1992-12-01

    This research was directed toward the investigation of nonlinear large displacements and moderate rotations of composite beam structures considering a finite element potential energy approach incorporating through the thickness shear strain as an analytical function. This approach was compared to large rotation theories. Test cases were run to evaluate numerical algorithms Riks method and displacement imposed techniques were employed. The limitations and advantages of both methods were considered. Loading arrangements included concentrated forces as well as moments.

  2. Demonstration of Vibrational Braille Code Display Using Large Displacement Micro-Electro-Mechanical Systems Actuators

    NASA Astrophysics Data System (ADS)

    Watanabe, Junpei; Ishikawa, Hiroaki; Arouette, Xavier; Matsumoto, Yasuaki; Miki, Norihisa

    2012-06-01

    In this paper, we present a vibrational Braille code display with large-displacement micro-electro-mechanical systems (MEMS) actuator arrays. Tactile receptors are more sensitive to vibrational stimuli than to static ones. Therefore, when each cell of the Braille code vibrates at optimal frequencies, subjects can recognize the codes more efficiently. We fabricated a vibrational Braille code display that used actuators consisting of piezoelectric actuators and a hydraulic displacement amplification mechanism (HDAM) as cells. The HDAM that encapsulated incompressible liquids in microchambers with two flexible polymer membranes could amplify the displacement of the MEMS actuator. We investigated the voltage required for subjects to recognize Braille codes when each cell, i.e., the large-displacement MEMS actuator, vibrated at various frequencies. Lower voltages were required at vibration frequencies higher than 50 Hz than at vibration frequencies lower than 50 Hz, which verified that the proposed vibrational Braille code display is efficient by successfully exploiting the characteristics of human tactile receptors.

  3. Mechanisms of defect production and atomic mixing in high energy displacement cascades: A molecular dynamics study

    SciTech Connect

    Diaz de la Rubia, T.; Guinan, M.W.

    1991-06-05

    We have performed molecular dynamics computer simulation studies of displacement cascades in Cu at low temperature. For 25 keV recoils we observe the splitting of a cascade into subcascades and show that cascades in Cu may lead to the formation of vacancy and interstitial dislocation loops. We discuss a new mechanism of defect production based on the observation of interstitial prismatic dislocation loop punching from cascades at 10 K. We also show that below the subcascade threshold, atomic mixing in the cascade is recoil-energy dependent and obtain a mixing efficiency that scales as the square root of the primary recoil energy. 44 refs., 12 figs.

  4. New type of eddy current sensor for large-displacement test

    Microsoft Academic Search

    Haifeng Pan; Huizhong Zhu; Zhibin Fu; Yuzheng Xu; Guanping Feng

    2001-01-01

    In this paper a new type of large displacement eddy current sensor is developed to overcome the three main disadvantages of the traditional eddy current senor. For a traditional sensor, the measurement range is limited and less than one half of the diameter of the measuring coil. The output is high sensitivity to the changes of the target material and

  5. Thermoacoustic energy analysis of transverse-pin and tortuous stacks at large acoustic displacements

    Microsoft Academic Search

    Konstantin I. Matveev

    2010-01-01

    A simplified method based on Rayleigh's criterion is developed for evaluating thermoacoustic power conversion in transverse-pin and tortuous stacks. Heat transfer and viscous losses are approximated by steady-flow correlations valid at large acoustic displacements with respect to a longitudinal pitch of a pin stack or a characteristic pore size of a random stack. A Lagrangian approach is employed to calculate

  6. NOVEL ELECTROTHERMAL BIMORPH ACTUATOR FOR LARGE OUT-OF-PLANE DISPLACEMENT AND FORCE

    E-print Network

    Technische Universiteit Delft

    for out-of-plane actuation that exploits the polymer constraint effect. The proposed concept is capable and other MEMS devices, where both large displacement and force are needed. The commonly used electrothermal of polymer could be employed, but the poor thermal conductivity still has to be overcome. Thus, an actuation

  7. Dynamics and thermodynamics of crystalline polymorphs: ?-glycine, analysis of variable-temperature atomic displacement parameters.

    PubMed

    Aree, Thammarat; Bürgi, Hans-Beat; Capelli, Silvia C

    2012-08-01

    Multitemperature synchrotron diffraction data to 0.5 Å resolution in the temperature range 10-298 K and neutron data at 18 K of the ?-glycine polymorph have been collected at the KEK photon factory (PF), SPring-8 and the Institut Laue Langevin (ILL) for the study of molecular motion in the crystal and of the associated thermodynamic functions. Atomic displacement parameters (ADPs) of non-H atoms are obtained from refinements based on nonspherical atomic scattering factors (invariom model) to minimize correlation between parameters describing thermal motion and valence electron density. The ADPs in the temperature range 50-298 K from SPring-8 connect smoothly with those from neutron diffraction at 18 K and 288-323 K. The combined ADPs from both sources covering the temperature range 18-323 K are used for a normal-mode analysis in the molecular mean field approximation. The lattice vibration frequencies from the ADP analysis and the internal vibration frequencies from an ONIOM (B3LYP/6-311+G(2d,p):PM3) calculation together with the Einstein, Debye, and Nernst-Lindemann models of heat capacity are used to calculate Cp, Hvib, and Svib values that are in good agreement with those from calorimetry. PMID:22746958

  8. Large displacement spring-like electro-mechanical thermal actuators with insulator constraint beams

    Microsoft Academic Search

    J. K. Luo; Y. Q. Fu; A. J. Flewitt; S. M. Spearing; N. A. Fleck; W. I. Milne

    2005-01-01

    A number of in-plane spring-like micro-electro-thermal-actuators with large displacements were proposed. The devices take the advantage of the large difference in the thermal expansion coefficients between the conductive arms and the insulator clamping beams. The constraint beams in one type (the spring) of these devices are horizontally positioned to restrict the expansion of the active arms in the x-direction, and

  9. Measurement of transient atomic displacements in thin films with picosecond and femtometer resolution

    E-print Network

    , and/or large pulse-to-pulse fluc- tuations, necessitating the examination of systems driven far from (Received 15 March 2014; accepted 25 April 2014; published online 6 May 2014) We report measurements to probe the atomic-scale dynamics and phonon conduction processes within systems close to equilibrium

  10. Amplifying transmission and compact suspension for a low-profile, large-displacement piezoelectric actuator

    PubMed Central

    Domke, J F; Rhee, C-H; Liu, Z; Wang, T D; Oldham, K R

    2012-01-01

    A low-profile, piezoelectrically-driven microactuator is presented that achieves very large stroke lengths within size constraints suitable for certain endoscopic microscopy applications. The actuator utilizes a transmission consisting of lever arm and chevron-beam structures to amplify high-force, low-displacement motion of a ceramic lead-zirconate-titanate (PZT) brick into large displacement of a translational platform. For ±120 V input, a full range of 486 ?m of motion is achieved, with natural frequency greater than 500 Hz. This corresponds to an anticipated In addition, the lateral translational platform is supported by a redesign of common folded silicon flexures to provide large transverse and vertical stiffness when the width of the actuator is limited. PMID:23180908

  11. Structural optimization of a large-displacement electromagnetic Lorentz force microactuator for optical switching applications

    Microsoft Academic Search

    Jeong Sam Han; Jong Soo Ko; Jan G Korvink

    2004-01-01

    This paper discusses optimization of an electromagnetic microactuator for large-displacement optical switching. The microactuator used in this research is a laterally driven electromagnetic one that provides parallel actuation to the silicon substrate surface (in-plane motion) using the Lorentz force. When the microactuator is driven by the distributed Lorentz force induced along the arch-shaped leaf springs, a buckling phenomenon in two

  12. Solvers for large-displacement fluid–structure interaction problems: segregated versus monolithic approaches

    Microsoft Academic Search

    Matthias Heil; Andrew L. Hazel; Jonathan Boyle

    2008-01-01

    We compare the relative performance of monolithic and segregated (partitioned) solvers for large- displacement fluid–structure\\u000a interaction (FSI) problems within the framework of oomph-lib, the object-oriented multi-physics finite-element library, available as open-source software at http:\\/\\/www.oomph-lib.org. Monolithic solvers are widely acknowledged to be more robust than their segregated counterparts, but are believed to be\\u000a too expensive for use in large-scale problems. We

  13. Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays

    PubMed Central

    Lu, S. G.; Chen, X.; Levard, T.; Diglio, P. J.; Gorny, L. J.; Rahn, C. D.; Zhang, Q. M.

    2015-01-01

    Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly. PMID:26079628

  14. Large Displacement in Relaxor Ferroelectric Terpolymer Blend Derived Actuators Using Al Electrode for Braille Displays.

    PubMed

    Lu, S G; Chen, X; Levard, T; Diglio, P J; Gorny, L J; Rahn, C D; Zhang, Q M

    2015-01-01

    Poly(vinylidene fluoride) (PVDF) based polymers are attractive for applications for artificial muscles, high energy density storage devices etc. Recently these polymers have been found great potential for being used as actuators for refreshable full-page Braille displays for visually impaired people in terms of light weight, miniaturized size, and larger displacement, compared with currently used lead zirconate titanate ceramic actuators. The applied voltages of published polymer actuators, however, cannot be reduced to meet the requirements of using city power. Here, we report the polymer actuator generating quite large displacement and blocking force at a voltage close to the city power. Our embodiments also show good self-healing performance and disuse of lead-containing material, which makes the Braille device safer, more reliable and more environment-friendly. PMID:26079628

  15. Dynamics and thermodynamics of crystalline polymorphs. 2. ?-Glycine, analysis of variable-temperature atomic displacement parameters.

    PubMed

    Aree, Thammarat; Bürgi, Hans-Beat; Minkov, Vasily S; Boldyreva, Elena V; Chernyshov, Dmitry; Törnroos, Karl W

    2013-08-22

    The molecular dynamics in the crystal and the thermodynamic functions of the ?-polymorph of glycine have been determined from a combination of molecular translation-libration frequencies reflecting the temperature dependence of atomic displacement parameters (ADPs), with frequencies derived from ONIOM(DFT:PM3) calculations on a 15-molecule ?-glycine cluster. ADPs have been obtained from variable-temperature diffraction data to 0.5 Å resolution collected with X-ray synchrotron (10-300 K) and sealed tube radiation (50-298 K). At the higher temperatures, the ADPs of ?-glycine from synchrotron are larger than those from sealed tube probably due to different experimental conditions. The lattice vibration frequencies from normal-mode analysis of ADPs and the internal vibration frequencies from ONIOM(B3LYP/6-311+G(2d,p):PM3) calculations agree with those from spectroscopy. Estimation of thermodynamic functions using the vibrational frequencies, the Einstein and Debye models of heat capacity, and the room-temperature compressibility provides C(p), H(vib), and S(vib) that agree with those from calorimetry. The ?-phase with higher H and G is found to be less stable than the ?-phase in the temperature range of the experiment. PMID:23865724

  16. Observation of depth-dependent atomic displacements related to dislocations in GaN by optical sectioning in the STEM

    NASA Astrophysics Data System (ADS)

    Lozano, J. G.; Guerrero-Lebrero, M. P.; Yasuhara, A.; Okinishi, E.; Zhang, S.; Humphreys, C. J.; Galindo, P. L.; Hirsch, P. B.; Nellist, P. D.

    2014-06-01

    We demonstrate that it is possible to observe depth-dependent atomic displacements in a GaN crystal due to the sufficiently small depth of field achievable in the aberration-corrected scanning transmission electron microscope. The depth-dependent displacements associated with the Eshelby twist of screw dislocations in GaN viewed end on are directly imaged, and makes possible the determination of the sign of the Burgers vector of the dislocation. The experimental results are in good agreement with theoretical images.

  17. Generation of decoherence-free displaced squeezed states of radiation fields and a squeezed reservoir for atoms in cavity QED

    E-print Network

    T. Werlang; R. Guzman; F. O. Prado; C. J. Villas-Boas

    2008-06-17

    We present a way to engineer an effective anti-Jaynes-Cumming and a Jaynes-Cumming interaction between an atomic system and a single cavity mode and show how to employ it in reservoir engineering processes. To construct the effective Hamiltonian, we analyse considered the interaction of an atomic system in a \\{Lambda} configuration, driven by classical fields, with a single cavity mode. With this interaction, we firstly show how to generate a decoherence-free displaced squeezed state for the cavity field. In our scheme, an atomic beam works as a reservoir for the radiation field trapped inside the cavity, as employed recently by S. Pielawa et al. [Phys. Rev. Lett. 98, 240401 (2007)] to generate an Einstein-Podolsky-Rosen entangled radiation state in high-Q resonators. In our scheme, all the atoms have to be prepared in the ground state and, as in the cited article, neither atomic detection nor precise interaction times between the atoms and the cavity mode are required. From this same interaction, we can also generate an ideal squeezed reservoir for atomic systems. For this purpose we have to assume, besides the engineered atom-field interaction, a strong decay of the cavity field (i.e., the cavity decay must be much stronger than the effective atom-field coupling). With this scheme, some interesting effects in the dynamics of an atom in a squeezed reservoir could be tested.

  18. Experiments on Methane Displacement by Carbon Dioxide in Large Coal Specimens

    NASA Astrophysics Data System (ADS)

    Liang, Weiguo; Zhao, Yangsheng; Wu, Di; Dusseault, Maurice B.

    2011-09-01

    Carbon dioxide (CO2) is considered to be the most important greenhouse gas in terms of overall effect. CO2 geological storage in coal beds is of academic and industrial interest because of economic synergies between greenhouse gas sequestration and coal bed methane (CH4) recovery by displacement/adsorption. Previously, most work focused on either theoretical analyses and mathematical simulations or gas adsorption-desorption experiments using coal particles of millimeter size or smaller. Those studies provided basic understanding of CH4 recovery by CO2 displacement in coal fragments, but more relevant and realistic investigations are still rare. To study the processes more realistically, we conducted experimental CH4 displacement by CO2 and CO2 sequestration with intact 100 × 100 × 200 mm coal specimens. The coal specimen permeability was measured first, and results show that the permeability of the specimen is different for CH4 and CO2; the CO2 permeability was found to be at least two orders of magnitude greater than that for CH4. Simultaneously, a negative exponential relationship between the permeability and the applied mean stress on the specimen was found. Under the experimental stress conditions, 17.5-28.0 volumes CO2 can be stored in one volume of coal, and the displacement ratio CO2-CH4 is as much as 7.0-13.9. The process of injection, adsorption and desorption, displacement, and output of gases proceeds smoothly under an applied constant pressure differential, and the CH4 content in the output gas amounted to 20-50% at early stages, persisting to 10-16% during the last stage of the experiments. Production rate and CH4 fraction are governed by complex factors including initial CH4 content, the pore and fissure fabric of the coal, the changes in this fabric as the result of differential adsorption of CO2, the applied stress, and so on. During CO2 injection and CH4 displacement, the coal can swell from effects of gas adsorption and desorption, leading to changes in the microstructure of the coal itself. Artificial stimulation (e.g. hydraulic fracturing) to improve coalbed transport properties for either CO2 sequestration or enhanced coal bed methane recovery will be necessary. The interactions of large-scale induced fractures with the fabric at the scale of observable fissures and fractures in the laboratory specimens, as well as to the pore scale processes associated with adsorption and desorption, remain of profound interest and a great challenge.

  19. Large-Deformation Displacement Transfer Functions for Shape Predictions of Highly Flexible Slender Aerospace Structures

    NASA Technical Reports Server (NTRS)

    Ko, William L.; Fleischer, Van Tran

    2013-01-01

    Large deformation displacement transfer functions were formulated for deformed shape predictions of highly flexible slender structures like aircraft wings. In the formulation, the embedded beam (depth wise cross section of structure along the surface strain sensing line) was first evenly discretized into multiple small domains, with surface strain sensing stations located at the domain junctures. Thus, the surface strain (bending strains) variation within each domain could be expressed with linear of nonlinear function. Such piecewise approach enabled piecewise integrations of the embedded beam curvature equations [classical (Eulerian), physical (Lagrangian), and shifted curvature equations] to yield closed form slope and deflection equations in recursive forms.

  20. On 'large-scale' stable fiber displacement during interfacial failure in metal matrix composites

    NASA Technical Reports Server (NTRS)

    Petrich, R. R.; Koss, D. A.; Hellmann, J. R.; Kallas, M. N.

    1993-01-01

    Experimental results are presented to show that interfacial failure in sapphire-reinforced niobium is characterized by 'large-scale' (5-15 microns) plasticity-controlled fiber displacements occurring under increasing loads. The results are based on the responses during thin-slice fiber pushout tests wherein the fiber is supported over a hole twice the fiber diameter. The results describe an interfacial failure process that should also occur near fiber ends during pullout when a fiber is well-bonded to a soft, ductile matrix, such that eventual failure occurs by shear within the matrix near the interface.

  1. Effect of mass of the primary knock-on atom on displacement cascade debris in alpha-iron

    Microsoft Academic Search

    Calder F Andrew; David J Bacon; Aleksandr Barashev; Y. N. Osetsky

    2008-01-01

    Results are presented from molecular dynamics (MD) simulations of displacement cascades created in ?-iron (Fe) by primary knock-on atoms (PKAs) with energy from 5 to 20 keV and mass chosen to represent C, Fe and Bi. Molecular Bi2 has also been simulated using two Bi PKAs, and PKA-Fe interaction potential has also been varied. Four effects are reported. First, the

  2. Evidence for large-scale effects of competition: niche displacement in Canada lynx and bobcat.

    PubMed

    Peers, Michael J L; Thornton, Daniel H; Murray, Dennis L

    2013-12-22

    Determining the patterns, causes and consequences of character displacement is central to our understanding of competition in ecological communities. However, the majority of competition research has occurred over small spatial extents or focused on fine-scale differences in morphology or behaviour. The effects of competition on broad-scale distribution and niche characteristics of species remain poorly understood but critically important. Using range-wide species distribution models, we evaluated whether Canada lynx (Lynx canadensis) or bobcat (Lynx rufus) were displaced in regions of sympatry. Consistent with our prediction, we found that lynx niches were less similar to those of bobcat in areas of sympatry versus allopatry, with a stronger reliance on snow cover driving lynx niche divergence in the sympatric zone. By contrast, bobcat increased niche breadth in zones of sympatry, and bobcat niches were equally similar to those of lynx in zones of sympatry and allopatry. These findings suggest that competitively disadvantaged species avoid competition at large scales by restricting their niche to highly suitable conditions, while superior competitors expand the diversity of environments used. Our results indicate that competition can manifest within climatic niche space across species' ranges, highlighting the importance of biotic interactions occurring at large spatial scales on niche dynamics. PMID:24174116

  3. Evidence for large-scale effects of competition: niche displacement in Canada lynx and bobcat

    PubMed Central

    Peers, Michael J. L.; Thornton, Daniel H.; Murray, Dennis L.

    2013-01-01

    Determining the patterns, causes and consequences of character displacement is central to our understanding of competition in ecological communities. However, the majority of competition research has occurred over small spatial extents or focused on fine-scale differences in morphology or behaviour. The effects of competition on broad-scale distribution and niche characteristics of species remain poorly understood but critically important. Using range-wide species distribution models, we evaluated whether Canada lynx (Lynx canadensis) or bobcat (Lynx rufus) were displaced in regions of sympatry. Consistent with our prediction, we found that lynx niches were less similar to those of bobcat in areas of sympatry versus allopatry, with a stronger reliance on snow cover driving lynx niche divergence in the sympatric zone. By contrast, bobcat increased niche breadth in zones of sympatry, and bobcat niches were equally similar to those of lynx in zones of sympatry and allopatry. These findings suggest that competitively disadvantaged species avoid competition at large scales by restricting their niche to highly suitable conditions, while superior competitors expand the diversity of environments used. Our results indicate that competition can manifest within climatic niche space across species’ ranges, highlighting the importance of biotic interactions occurring at large spatial scales on niche dynamics. PMID:24174116

  4. Generating atomic multi-dimensional entangled states under large atom-cavity detuning

    E-print Network

    Peng Shi; Li-Bo Chen; Wen-Dong Li; Chun-Nian Ren; Chun-Hong Zheng; Yong-Jian Gu

    2012-09-25

    We propose a scheme to deterministically generate atomic two-dimensional and three-dimensional entangled states by passing two 87Rb atoms through a high-Q bi-mode cavity alternately. The scheme is insensitive to atomic spontaneous decay because of large atom-cavity detuning, the influence of cavity decay is also discussed. Our strictly numerical simulation shows our proposal is good enough to demonstrate the generation of atomic entanglement with high fidelity and within the current experimental technologies.

  5. Evolution of the superposition of displaced number states with the two-atom multiphoton Jaynes-Cummings model: interference and entanglement

    E-print Network

    Faisal Aly Aly El-Orany

    2005-12-14

    In this paper we study the evolution of the two two-level atoms interacting with a single-mode quantized radiation field, namely, two-atom multiphoton Jaynes-Cummings model when the radiation field and atoms are initially prepared in the superpostion of displaced number states and excited atomic states, respectively. For this system we investigate the atomic inversion, Wigner function, phase distribution and entanglement.

  6. Giant atomic displacement at a magnetic phase transition in metastable Mn3O4

    NASA Astrophysics Data System (ADS)

    Hirai, S.; dos Santos, A. M.; Shapiro, M. C.; Molaison, J. J.; Pradhan, N.; Guthrie, M.; Tulk, C. A.; Fisher, I. R.; Mao, W. L.

    2013-01-01

    We present x-ray, neutron scattering, and heat capacity data that reveal a coupled first-order magnetic and structural phase transition of the metastable mixed-valence postspinel compound Mn3O4 at 210 K. Powder neutron diffraction measurements reveal a magnetic structure in which Mn3+ spins align antiferromagnetically along the edge-sharing a axis, with a magnetic propagation vector k=[1/2,0,0]. In contrast, the Mn2+ spins, which are geometrically frustrated, do not order until a much lower temperature. Although the Mn2+ spins do not directly participate in the magnetic phase transition at 210 K, structural refinements reveal a large atomic shift at this phase transition, corresponding to a physical motion of approximately 0.25 Å, even though the crystal symmetry remains unchanged. This “giant” response is due to the coupled effect of built-in strain in the metastable postspinel structure with the orbital realignment of the Mn3+ ion.

  7. A large outbreak of shigellosis commencing in an internally displaced population, Papua New Guinea, 2013

    PubMed Central

    Benny, Edwin; Mesere, Kelly; Pavlin, Boris I; Yakam, Logan; Ford, Rebecca; Yoannes, Mition; Kisa, Debbie; Abdad, Mohammad Y; Menda, Lincoln; Greenhill, Andrew R

    2014-01-01

    Objective The objective of this study was to investigate a large outbreak of shigellosis in Papua New Guinea that began in a camp for internally displaced persons before spreading throughout the general community. Methods Outbreak mitigation strategies were implemented in the affected area to curtail the spread of the disease. Data were collected from the surveillance system and analysed by time, place and person. Rectal swab samples were tested by standard culture methods and real-time polymerase chain reaction to determine the etiology of the outbreak. Results Laboratory analysis at two independent institutions established that the outbreak was caused by Shigella sp., with one strain further characterized as Shigella flexneri serotype 2. Approximately 1200 suspected cases of shigellosis were reported in a two-month period from two townships in Morobe Province, Papua New Guinea. The outbreak resulted in at least five deaths, all in young children. Discussion This outbreak of shigellosis highlights the threat of enteric diseases to vulnerable populations such as internally displaced persons in Papua New Guinea, as has been observed in other global settings. PMID:25648967

  8. Long-delayed bright dancing sprite with large Horizontal displacement from its parent flash

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Lu, Gaopeng; Lee, Li-Jou; Feng, Guili

    2015-07-01

    We reported in this paper the observation of a very bright long-delayed dancing sprite with distinct horizontal displacement from its parent stroke. The dancing sprite lasted only 60 ms, and the morphology consisted of three fields with two slim dim sprite elements in the first two fields and a very bright large element in the third field, different from other observations where the dancing sprites usually contained multiple elements over a longer time interval, and the sprite shape and brightness in the video field are often similar to the previous fields. The bright sprite was displaced at least 38 km from its parent cloud-to-ground (CG) stroke and occurred over comparatively higher cloud top region. The parent flash of this compact dancing sprite was of positive polarity, with only one return stroke (approximately +24 kA) and obvious continuing current process, and the charge moment change of stroke was small (barely above the threshold for sprite production). All the sprite elements occurred during the continuing current stage, and the bright long-delayed sprite element induced a considerable current pulse. The dancing feature of this sprite may be linked to the electrical charge structure, dynamics and microphysics of parent storm, and the inferred development of parent CG flash was consistent with previous very high-frequency (VHF) observations of lightning in the same region.

  9. Determination of temperature-dependent atomic displacements in the Ca10Ir4As8(Fe2As2)5 superconductor with a metallic spacer layer

    NASA Astrophysics Data System (ADS)

    Paris, E.; Joseph, B.; Iadecola, A.; Marini, C.; Kudo, K.; Mitsuoka, D.; Nohara, M.; Mizokawa, T.; Saini, N. L.

    2014-09-01

    We have used the combination of Fe K-edge and Ir L3-edge x-ray absorption measurements as a function of temperature to investigate local atomic displacements in the newly discovered Ca10Ir4As8(Fe2As2)5 superconducting system. We find relatively relaxed Fe-Fe atomic pair correlations with large displacements in the FeAs4 tetrahedra, revealed by Fe K-edge extended x-ray absorption fine structure (EXAFS) analysis. Similarly, the temperature dependence of Ir L3-edge EXAFS shows nanoscale disorder in the IrAs layer that should have a significant effect on the active FeAs-layer characteristics. Furthermore, x-ray absorption near edge structure data are presented to discuss the evolution of the unoccupied electronic states revealing the marginal role of spin-orbit coupling, while the interlayer interactions and disorder should be important for describing the physics of the Ca10Ir4As8(Fe2As2)5 system.

  10. Evolution of Rupture Style with Accumulation of Fault Displacement during Large-scale Biaxial Friction Experiments

    NASA Astrophysics Data System (ADS)

    Xu, S.; Fukuyama, E.; Yamashita, F.; Mizoguchi, K.; Takizawa, S.; Kawakata, H.

    2014-12-01

    We report results with Indian Gabbro (Vs=3.62km/s) that are obtained from a series of large-scale biaxial friction experiments conducted at NIED. We focus on strain gage array data of stick-slip events loaded with 0.01mm/s and under 6.7MPa normal stress, and find the following: (1) During early stage when the contact surface is relatively intact, ruptures mainly behave as slow-slip events, with a transition from extremely slow slip (~ 10 m/s) to normal slow slip (~ 100 m/s). (2) With the accumulation of total fault displacement, grooves indicative of locally high normal-stress patches (i.e. asperities) are generated along the sliding surface, which are primarily elongated along the loading direction and are associated with gouge formation. On the other hand, the rest part of the surface continues being polished, indicated by a contrast in light reflectivity with respect to the initial level. At this stage, rupture speeds start to increase but are still well below the shear wave speed (~ 1/4Vs). (3) After long enough total fault displacement (> 500mm), grooves and gouges of a sufficient amount are generated. The following ruptures then show a classic behavior as documented by Ohnaka (2000), which composes of a quasi-static phase, an accelerating phase, and an unstable propagation phase. Although the terminal propagation speed usually reaches a level comparable to the shear wave speed, there is a significant variability for the earlier phases among different events, suggesting that those earlier phases are more sensitive to the evolving local fault structure and/or stress heterogeneity. Further investigation reveals that fault properties (e.g. grooves and gouges) as a function of the accumulated displacement can influence both the macroscopic and the local strain drop, which are most-likely responsible for the evolution of rupture behavior under the same macroscopic loading conditions. We aim to quantify this relation in a continued study.

  11. Hardware Support for Large Atomic Units in Dynamically Scheduled Machines

    E-print Network

    Melvin, Stephen

    Hardware Support for Large Atomic Units in Dynamically Scheduled Machines Stephen W. Melvin Michael. This limitation is due in part to the fact that the units of work that the hardware treats as indivisible of the various units of work that a processor considers indi- visible, or atomic. We argue that by allowing

  12. Population of displaced levels of aluminum and copper atoms in plasma jets

    Microsoft Academic Search

    L. I. Kiselevskii; V. D. Shimanovich

    1965-01-01

    Population studies have been made for the displaced levels of aluminum 4s'4P°1\\/2,3\\/2, 5\\/2 and copper4D1\\/2, 3\\/2, 5\\/2, 7\\/2 in a plasma jet entering an evacuated space. It is found that there is an increase in the relative population (which may exceed the equilibrium value) for unstable levels of high autoionization probability. This is considered to result from accentuated recombination to

  13. Large spin relaxation rates in trapped submerged-shell atoms

    SciTech Connect

    Connolly, Colin B.; Au, Yat Shan; Doret, S. Charles; Doyle, John M. [Department of Physics, Harvard University, 17 Oxford Street, Cambridge, Massachusetts 02138 (United States); Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138 (United States); Ketterle, Wolfgang [Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Harvard-MIT Center for Ultracold Atoms, Cambridge, Massachusetts 02138 (United States)

    2010-01-15

    Spin relaxation due to atom-atom collisions is measured for magnetically trapped erbium and thulium atoms at a temperature near 500 mK. The rate constants for Er-Er and Tm-Tm collisions are 3.0x10{sup -10} and 1.1x10{sup -10} cm{sup 3} s{sup -1}, respectively, 2-3 orders of magnitude larger than those observed for highly magnetic S-state atoms. This is strong evidence for an additional, dominant, spin relaxation mechanism, electronic interaction anisotropy, in collisions between these 'submerged-shell,' Lnot =0 atoms. These large spin relaxation rates imply that evaporative cooling of these atoms in a magnetic trap will be highly inefficient.

  14. Multiple Displacement Amplification Enables Large-Scale Clonal Analysis following Retroviral Gene Therapy?

    PubMed Central

    Bleier, S.; Maier, P.; Allgayer, H.; Wenz, F.; Zeller, W. J.; Fruehauf, S.; Laufs, S.

    2008-01-01

    Analysis of the fate of retrovirally transduced cells after transplantation is often hampered by the scarcity of available DNA. We evaluated a promising method for whole-genome amplification, called multiple displacement amplification (MDA), with respect to even and accurate representation of retrovirally transduced genomic DNA. We proved that MDA is a suitable method to subsequently quantify engraftment efficiencies by quantitative real-time PCR by analyzing retrovirally transduced DNA in a background of untransduced DNA and retroviral integrations found in primary material from a retroviral transplantation model. The portion of these retroviral integrations in the amplified samples was 1.02-fold (range 0.2, to 2.1-fold) the portion determined in the original genomic DNA. Integration site analysis by ligation-mediated PCR (LM-PCR) is essential for the detection of retroviral integrations. The combination of MDA and LM-PCR showed an increase in the sensitivity of integration site analysis, as a specific integration site could be detected in a background of untransduced DNA, while the transduced DNA made up only 0.001%. These results show for the first time that MDA enables large-scale sensitive detection and reliable quantification of retrovirally transduced human genomic DNA and therefore facilitates follow-up analysis in gene therapy studies even from the smallest amounts of starting material. PMID:18077708

  15. Multiple displacement amplification enables large-scale clonal analysis following retroviral gene therapy.

    PubMed

    Bleier, S; Maier, P; Allgayer, H; Wenz, F; Zeller, W J; Fruehauf, S; Laufs, S

    2008-03-01

    Analysis of the fate of retrovirally transduced cells after transplantation is often hampered by the scarcity of available DNA. We evaluated a promising method for whole-genome amplification, called multiple displacement amplification (MDA), with respect to even and accurate representation of retrovirally transduced genomic DNA. We proved that MDA is a suitable method to subsequently quantify engraftment efficiencies by quantitative real-time PCR by analyzing retrovirally transduced DNA in a background of untransduced DNA and retroviral integrations found in primary material from a retroviral transplantation model. The portion of these retroviral integrations in the amplified samples was 1.02-fold (range 0.2, to 2.1-fold) the portion determined in the original genomic DNA. Integration site analysis by ligation-mediated PCR (LM-PCR) is essential for the detection of retroviral integrations. The combination of MDA and LM-PCR showed an increase in the sensitivity of integration site analysis, as a specific integration site could be detected in a background of untransduced DNA, while the transduced DNA made up only 0.001%. These results show for the first time that MDA enables large-scale sensitive detection and reliable quantification of retrovirally transduced human genomic DNA and therefore facilitates follow-up analysis in gene therapy studies even from the smallest amounts of starting material. PMID:18077708

  16. Subpixelic Measurement of Large 1D Displacements: Principle, Processing Algorithms, Performances and Software

    PubMed Central

    Guelpa, Valérian; Laurent, Guillaume J.; Sandoz, Patrick; Zea, July Galeano; Clévy, Cédric

    2014-01-01

    This paper presents a visual measurement method able to sense 1D rigid body displacements with very high resolutions, large ranges and high processing rates. Sub-pixelic resolution is obtained thanks to a structured pattern placed on the target. The pattern is made of twin periodic grids with slightly different periods. The periodic frames are suited for Fourier-like phase calculations—leading to high resolution—while the period difference allows the removal of phase ambiguity and thus a high range-to-resolution ratio. The paper presents the measurement principle as well as the processing algorithms (source files are provided as supplementary materials). The theoretical and experimental performances are also discussed. The processing time is around 3 ?s for a line of 780 pixels, which means that the measurement rate is mostly limited by the image acquisition frame rate. A 3-? repeatability of 5 nm is experimentally demonstrated which has to be compared with the 168 ?m measurement range. PMID:24625736

  17. Large-displacement structural durability analyses of simple bend specimen emulating rocket nozzle liners

    NASA Technical Reports Server (NTRS)

    Arya, Vinod K.; Halford, Gary R.

    1994-01-01

    Large-displacement elastic and elastic-plastic, finite-element stress-strain analyses of an oxygen-tree high-conductivity (OFHC) copper plate specimen were performed using an updated Lagrangian formulation. The plate specimen is intended for low-cost experiments that emulate the most important thermomechanical loading and failure modes of a more complex rocket nozzle. The plate, which is loaded in bending at 593 C, contains a centrally located and internally pressurized channel. The cyclic crack initiation lives were estimated using the results from the analyses and isothermal strain-controlled low-cycle fatigue data for OFHC copper. A comparison of the predicted and experimental cyclic lives showed that an elastic analysis predicts a longer cyclic life than that observed in experiments by a factor greater than 4. The results from elastic-plastic analysis for the plate bend specimen, however, predicted a cyclic life in close agreement with experiment, thus justifying the need for the more rigorous stress-strain analysis.

  18. A threaded wobble motor with a 6-pole stator-a micro motor generating large linear displacement

    Microsoft Academic Search

    Tetsuhiko Iizuka; Hiroyuki Fujita

    1996-01-01

    This paper deals with the driving principle and the experimental demonstration of a micro motor which can convert rotation into linear motion and generate large displacement. The motor is a wobble type one; its rotor and stators have screw threads. When the rotor turns, it moves linearly in the axial direction like a screw. The range of linear motion is

  19. Spin liquid phases of large spin Mott insulating ultracold atoms

    NASA Astrophysics Data System (ADS)

    Rutkowski, Todd C.; Lawler, Michael J.

    2015-03-01

    Understanding exotic forms of magnetism, primarily those driven by large spin fluctuations such as the quantum spin liquid state, is a major goal of condensed matter physics. But, the relatively small number of viable candidate materials poses a difficulty. We believe this problem can be solved by Mott insulating ultracold atoms with large spin moments that interact via whole-atom exchange. The large spin fluctuations of this exchange could stabilize exotic physics similar to condensed matter systems, all in an extremely tunable environment. We have approached the problem by performing a mean field theory for spin-f bosons in an optical lattice which is exact in the large-f limit. This setting is similar to that of SU(N) magnetism proposed for alkali-earth atoms but without the SU(N) symmetry. We find that states with long-range order, such as the spin nematic phase of f = 1 Na atoms, become highly entangled spin-liquid-like states for f = 3 Cr atoms. This is evidence that the magnetic phase diagram for Mott insulating atoms at larger spins generically contains exotic forms of magnetism.

  20. Atomic Structure Prediction with Large-Scale High Performance Computing

    NASA Astrophysics Data System (ADS)

    Wang, Cai-Zhuang; Harmon, Bruce; Nguyen, Manh Cuong; Zhao, Xin; Ho, Kai-Ming; Ames Lab, US DOE Team

    2014-03-01

    Many unknown binary or ternary materials for energy applications have very complex crystal structures, containing large number of atoms in their unit cells and possible uncertainty in composition. Computational prediction for atomic structures of such complex materials is a highly demanding work. Advances in modern large-scale high performance computational resources and computational algorithms now make it feasible to perform an efficient crystal structure prediction. We developed an adaptive genetic algorithm to perform large-scale structure search on high performance supercomputer. Examples of successful structure prediction/solving of complex materials will be presented. Further applications of the adaptive genetic algorithm to aid material discoveries will be discussed.

  1. Displacement, county social cohesion and depression after a large-scale traumatic event

    PubMed Central

    Lê, Félice; Tracy, Melissa; Norris, Fran H.; Galea, Sandro

    2013-01-01

    Background Depression is a common and potentially debilitating consequence of traumatic events. Mass traumatic events cause wide-ranging disruptions to community characteristics, influencing the population risk of depression. In the aftermath of such events, population displacement is common. Stressors associated with displacement may increase risk of depression directly. Indirectly, persons who are displaced may experience erosion in social cohesion, further exacerbating their risk for depression. Methods Using data from a population-based cross-sectional survey of adults living in the 23 southernmost counties of Mississippi (N = 708), we modeled the independent and joint relations of displacement and county-level social cohesion with depression 18–24 months after Hurricane Katrina. Results After adjustment for individual- and county-level sociodemographic characteristics and county-level hurricane exposure, joint exposure to both displacement and low social cohesion was associated with substantially higher log-odds of depression (b = 1.34 [0.86–1.83]). Associations were much weaker for exposure only to low social cohesion (b = 0.28 [?0.35–0.90]) or only to displacement (b = 0.04 [?0.80– 0.88]). The associations were robust to additional adjustment for individually perceived social cohesion and social support. Conclusion Addressing the multiple, simultaneous disruptions that are a hallmark of mass traumatic events is important to identify vulnerable populations and understand the psychological ramifications of these events. PMID:23644724

  2. Magnetic transport of trapped cold atoms over a large distance

    Microsoft Academic Search

    Markus Greiner; Immanuel Bloch; Theodor W. Hänsch; Tilman Esslinger

    2001-01-01

    We report the transport of magnetically trapped cold atoms over a large distance. Atoms are captured in a magneto-optical trap (MOT) and loaded into a magnetic quadrupole trap. The quadrupole potential is then moved over a distance of 33 cm into an ultra-high-vacuum (UHV) chamber using a chain of quadrupole coils. By running suitable currents through the quadrupole coil pairs

  3. Electron transfer and ionic displacements as the origin of the 2D electron gas at the LAO/STO interface: Direct measurements with atomic-column spatial resolution.

    SciTech Connect

    Cantoni, Claudia [ORNL; Gazquez Alabart, Jaume [ORNL; Miletto Granozio, Fabio [Universita` di Napoli “Federico II”; Oxley, Mark P [ORNL; Varela del Arco, Maria [ORNL; Lupini, Andrew R [ORNL; Pennycook, Stephen J [ORNL; Aruta, Carmela [Universita` di Napoli “Federico II”; Scotti di Uccio, Umberto [Universita` di Napoli “Federico II”; Perna, Paolo [Universita` di Napoli “Federico II”; Maccariello, Davide [Universita` di Napoli “Federico II”

    2012-01-01

    We present direct, atomic-column-resolved scanning transmission electron microscopy and electron energy loss measurements of atomic displacements and Ti valence in abrupt, conductive LAO/STO interfaces. We find that two distinct but interrelated mechanisms are responsible for screening the diverging electric potential in the LAO film: 1) charge injection in the interfacial Ti planes, and 2) dielectric relaxation in both LAO and STO through ionic displacements. The injected charge density decays over a length of nearly 3 unit cells within the STO substrate. The total injected charge is lower than predicted by pure electronic reconstruction. The origin of this discrepancy is attributed to cation and oxygen displacements, which we observe in both LAO and STO, and generate a polarization opposite to the intrinsic polarization of the LAO film. Our data attribute a minor role to oxygen vacancies and cation intermixing.

  4. Prospects for atomic clocks based on large ion crystals

    E-print Network

    Kyle Arnold; Elnur Haciyev; Eduardo Paez; Chern Hui Lee; John Bollinger; M. D. Barrett

    2015-07-08

    We investigate the feasibility of precision frequency metrology with large ion crystals. For clock candidates with a negative differential static polarisability, we show that micromotion effects should not impede the performance of the clock. Using Lu+ as a specific example, we show that quadrupole shifts due to the electric fields from neighbouring ions do not significantly affect clock performance. We also show that effects from the tensor polarisability can be effectively managed with a compensation laser at least for a small number of ions (ion-based atomic clocks, allowing them to achieve stability levels comparable to neutral atoms in optical lattices and a viable path to greater levels of accuracy.

  5. Prospects for atomic clocks based on large ion crystals

    E-print Network

    Arnold, Kyle; Paez, Eduardo; Lee, Chern Hui; Bollinger, John; Barrett, M D

    2015-01-01

    We investigate the feasibility of precision frequency metrology with large ion crystals. For clock candidates with a negative differential static polarisability, we show that micromotion effects should not impede the performance of the clock. Using Lu+ as a specific example, we show that quadrupole shifts due to the electric fields from neighbouring ions do not significantly affect clock performance. We also show that effects from the tensor polarisability can be effectively managed with a compensation laser at least for a small number of ions (ion-based atomic clocks, allowing them to achieve stability levels comparable to neutral atoms in optical lattices and a viable path to greater levels of accuracy.

  6. Experiments on Methane Displacement by Carbon Dioxide in Large Coal Specimens

    Microsoft Academic Search

    Weiguo Liang; Yangsheng Zhao; Di Wu; Maurice B. Dusseault

    2011-01-01

    Carbon dioxide (CO2) is considered to be the most important greenhouse gas in terms of overall effect. CO2 geological storage in coal beds is of academic and industrial interest because of economic synergies between greenhouse gas\\u000a sequestration and coal bed methane (CH4) recovery by displacement\\/adsorption. Previously, most work focused on either theoretical analyses and mathematical simulations\\u000a or gas adsorption–desorption experiments

  7. Theory of a compound large-angle atom beam splitter

    SciTech Connect

    Muradyan, A. Zh.; Poghosyan, A. A.; Berman, P. R. [Department of Physics, Yerevan State University, 1 Alex Manookian, Yerevan 375025, (Armenia); Michigan Center for Theoretical Physics, FOCUS Center, and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1012, USA (United States)

    2003-09-01

    A theory of an atom beam splitter is developed involving the interaction of standing-wave field pulses with {lambda}-type atoms. The beam splitter consists of two interaction zones, both treated in the Raman-Nath approximation. There is an initial, off-resonant field (or fields) that prepares the initial atomic state, followed by interaction with a pair of standing-wave field pulses. Using this configuration one is able to create a large-angle beam splitter with a significant suppression of unwanted momentum components. The roles of relaxation and a frequency chirp are investigated, as are initial conditions for which both ground states of the {lambda} scheme are prepared by the first field. It is shown that the scheme is rather robust against fluctuations of system parameters.

  8. Determination of the shear buckling load of a large polymer composite I-section using strain and displacement sensors.

    PubMed

    Park, Jin Y; Lee, Jeong Wan

    2012-01-01

    This paper presents a method and procedure of sensing and determining critical shear buckling load and corresponding deformations of a comparably large composite I-section using strain rosettes and displacement sensors. The tested specimen was a pultruded composite beam made of vinyl ester resin, E-glass and carbon fibers. Various coupon tests were performed before the shear buckling test to obtain fundamental material properties of the I-section. In order to sensitively detect shear buckling of the tested I-section, twenty strain rosettes and eight displacement sensors were applied and attached on the web and flange surfaces. An asymmetric four-point bending loading scheme was utilized for the test. The loading scheme resulted a high shear and almost zero moment condition at the center of the web panel. The web shear buckling load was determined after analyzing the obtained test data from strain rosettes and displacement sensors. Finite element analysis was also performed to verify the experimental results and to support the discussed experimental approach. PMID:23443364

  9. Atomic displacement parameters and structural disorder of oxygen ions in the CexZr1-xO2 solid solutions (0.12<=x<=1.0): Possible factors of high catalytic activity of ceria-zirconia catalysts

    NASA Astrophysics Data System (ADS)

    Yashima, Masatomo; Wakita, Takahiro

    2009-04-01

    Crystal structures and electron-density distributions of ceria-zirconia CexZr1-xO2 compounds have been studied by the maximum-entropy method (MEM) and MEM-based pattern fitting combined with the Rietveld method using high-angular-resolution synchrotron x-ray powder diffraction data. The isotropic atomic displacement parameter of the oxygen atoms U(O) in Ce0.5Zr0.5O2 has a maximum value in CexZr1-xO2 (0.12?x ?1.0). Electron-density distribution of Ce0.5Zr0.5O2 shows a large spatial distribution of the oxygen ions. The greater U(O) and large spatial distribution of oxygen ions in Ce0.5Zr0.5O2 are possible factors of its higher catalytic activity.

  10. Search for Displaced Supersymmetry in Events with an Electron and a Muon with Large Impact Parameters

    NASA Astrophysics Data System (ADS)

    Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Erö, J.; Friedl, M.; Frühwirth, R.; Ghete, V. M.; Hartl, C.; Hörmann, N.; Hrubec, J.; Jeitler, M.; Kiesenhofer, W.; Knünz, V.; Krammer, M.; Krätschmer, I.; Liko, D.; Mikulec, I.; Rabady, D.; Rahbaran, B.; Rohringer, H.; Schöfbeck, R.; Strauss, J.; Taurok, A.; Treberer-Treberspurg, W.; Waltenberger, W.; Wulz, C.-E.; Mossolov, V.; Shumeiko, N.; Suarez Gonzalez, J.; Alderweireldt, S.; Bansal, M.; Bansal, S.; Cornelis, T.; De Wolf, E. A.; Janssen, X.; Knutsson, A.; Luyckx, S.; Ochesanu, S.; Rougny, R.; Van De Klundert, M.; Van Haevermaet, H.; Van Mechelen, P.; Van Remortel, N.; Van Spilbeeck, A.; Blekman, F.; Blyweert, S.; D'Hondt, J.; Daci, N.; Heracleous, N.; Keaveney, J.; Lowette, S.; Maes, M.; Olbrechts, A.; Python, Q.; Strom, D.; Tavernier, S.; Van Doninck, W.; Van Mulders, P.; Van Onsem, G. P.; Villella, I.; Caillol, C.; Clerbaux, B.; De Lentdecker, G.; Dobur, D.; Favart, L.; Gay, A. P. R.; Grebenyuk, A.; Léonard, A.; Mohammadi, A.; Perniè, L.; Reis, T.; Seva, T.; Thomas, L.; Vander Velde, C.; Vanlaer, P.; Wang, J.; Zenoni, F.; Adler, V.; Beernaert, K.; Benucci, L.; Cimmino, A.; Costantini, S.; Crucy, S.; Dildick, S.; Fagot, A.; Garcia, G.; Mccartin, J.; Ocampo Rios, A. A.; Ryckbosch, D.; Salva Diblen, S.; Sigamani, M.; Strobbe, N.; Thyssen, F.; Tytgat, M.; Yazgan, E.; Zaganidis, N.; Basegmez, S.; Beluffi, C.; Bruno, G.; Castello, R.; Caudron, A.; Ceard, L.; Da Silveira, G. G.; Delaere, C.; du Pree, T.; Favart, D.; Forthomme, L.; Giammanco, A.; Hollar, J.; Jafari, A.; Jez, P.; Komm, M.; Lemaitre, V.; Nuttens, C.; Pagano, D.; Perrini, L.; Pin, A.; Piotrzkowski, K.; Popov, A.; Quertenmont, L.; Selvaggi, M.; Vidal Marono, M.; Vizan Garcia, J. M.; Beliy, N.; Caebergs, T.; Daubie, E.; Hammad, G. H.; Aldá Júnior, W. L.; Alves, G. A.; Brito, L.; Correa Martins Junior, M.; Dos Reis Martins, T.; Mora Herrera, C.; Pol, M. E.; Carvalho, W.; Chinellato, J.; Custódio, A.; Da Costa, E. M.; De Jesus Damiao, D.; De Oliveira Martins, C.; Fonseca De Souza, S.; Malbouisson, H.; Matos Figueiredo, D.; Mundim, L.; Nogima, H.; Prado Da Silva, W. L.; Santaolalla, J.; Santoro, A.; Sznajder, A.; Tonelli Manganote, E. J.; Vilela Pereira, A.; Bernardes, C. A.; Dogra, S.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.; Genchev, V.; Iaydjiev, P.; Marinov, A.; Piperov, S.; Rodozov, M.; Stoykova, S.; Sultanov, G.; Vutova, M.; Dimitrov, A.; Glushkov, I.; Hadjiiska, R.; Kozhuharov, V.; Litov, L.; Pavlov, B.; Petkov, P.; Bian, J. G.; Chen, G. M.; Chen, H. S.; Chen, M.; Du, R.; Jiang, C. H.; Plestina, R.; Romeo, F.; Tao, J.; Wang, Z.; Asawatangtrakuldee, C.; Ban, Y.; Liu, S.; Mao, Y.; Qian, S. J.; Wang, D.; Zhang, L.; Zou, W.; Avila, C.; Chaparro Sierra, L. F.; Florez, C.; Gomez, J. P.; Gomez Moreno, B.; Sanabria, J. C.; Godinovic, N.; Lelas, D.; Polic, D.; Puljak, I.; Antunovic, Z.; Kovac, M.; Brigljevic, V.; Kadija, K.; Luetic, J.; Mekterovic, D.; Sudic, L.; Attikis, A.; Mavromanolakis, G.; Mousa, J.; Nicolaou, C.; Ptochos, F.; Razis, P. A.; Bodlak, M.; Finger, M.; Finger, M.; Assran, Y.; Ellithi Kamel, A.; Mahmoud, M. A.; Radi, A.; Kadastik, M.; Murumaa, M.; Raidal, M.; Tiko, A.; Eerola, P.; Fedi, G.; Voutilainen, M.; Härkönen, J.; Karimäki, V.; Kinnunen, R.; Kortelainen, M. J.; Lampén, T.; Lassila-Perini, K.; Lehti, S.; Lindén, T.; Luukka, P.; Mäenpää, T.; Peltola, T.; Tuominen, E.; Tuominiemi, J.; Tuovinen, E.; Wendland, L.; Talvitie, J.; Tuuva, T.; Besancon, M.; Couderc, F.; Dejardin, M.; Denegri, D.; Fabbro, B.; Faure, J. L.; Favaro, C.; Ferri, F.; Ganjour, S.; Givernaud, A.; Gras, P.; Hamel de Monchenault, G.; Jarry, P.; Locci, E.; Malcles, J.; Rander, J.; Rosowsky, A.; Titov, M.; Baffioni, S.; Beaudette, F.; Busson, P.; Charlot, C.; Dahms, T.; Dalchenko, M.; Dobrzynski, L.; Filipovic, N.; Florent, A.; Granier de Cassagnac, R.; Mastrolorenzo, L.; Miné, P.; Mironov, C.; Naranjo, I. N.; Nguyen, M.; Ochando, C.; Paganini, P.; Regnard, S.; Salerno, R.; Sauvan, J. B.; Sirois, Y.; Veelken, C.; Yilmaz, Y.; Zabi, A.; Agram, J.-L.; Andrea, J.; Aubin, A.; Bloch, D.; Brom, J.-M.; Chabert, E. C.; Collard, C.; Conte, E.; Fontaine, J.-C.; Gelé, D.; Goerlach, U.; Goetzmann, C.; Le Bihan, A.-C.; Van Hove, P.; Gadrat, S.; Beauceron, S.; Beaupere, N.; Boudoul, G.; Bouvier, E.; Brochet, S.; Carrillo Montoya, C. A.; Chasserat, J.; Chierici, R.; Contardo, D.; Depasse, P.; El Mamouni, H.; Fan, J.; Fay, J.; Gascon, S.; Gouzevitch, M.; Ille, B.; Kurca, T.; Lethuillier, M.; Mirabito, L.; Perries, S.; Ruiz Alvarez, J. D.; Sabes, D.; Sgandurra, L.; Sordini, V.; Vander Donckt, M.; Verdier, P.; Viret, S.; Xiao, H.; Tsamalaidze, Z.; Autermann, C.; Beranek, S.

    2015-02-01

    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at ?{s }=8 TeV . Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7 fb-1 . Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e -? final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e -? final state via R -parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to c ? =2 cm , excluding masses below 790 GeV at 95% confidence level.

  11. Search for displaced supersymmetry in events with an electron and a muon with large impact parameters.

    PubMed

    Khachatryan, V; Sirunyan, A M; Tumasyan, A; Adam, W; Bergauer, T; Dragicevic, M; Erö, J; Friedl, M; Frühwirth, R; Ghete, V M; Hartl, C; Hörmann, N; Hrubec, J; Jeitler, M; Kiesenhofer, W; Knünz, V; Krammer, M; Krätschmer, I; Liko, D; Mikulec, I; Rabady, D; Rahbaran, B; Rohringer, H; Schöfbeck, R; Strauss, J; Taurok, A; Treberer-Treberspurg, W; Waltenberger, W; Wulz, C-E; Mossolov, V; Shumeiko, N; Suarez Gonzalez, J; Alderweireldt, S; Bansal, M; Bansal, S; Cornelis, T; De Wolf, E A; Janssen, X; Knutsson, A; Luyckx, S; Ochesanu, S; Rougny, R; Van De Klundert, M; Van Haevermaet, H; Van Mechelen, P; Van Remortel, N; Van Spilbeeck, A; Blekman, F; Blyweert, S; D'Hondt, J; Daci, N; Heracleous, N; Keaveney, J; Lowette, S; Maes, M; Olbrechts, A; Python, Q; Strom, D; Tavernier, S; Van Doninck, W; Van Mulders, P; Van Onsem, G P; Villella, I; Caillol, C; Clerbaux, B; De Lentdecker, G; Dobur, D; Favart, L; Gay, A P R; Grebenyuk, A; Léonard, A; Mohammadi, A; Perniè, L; Reis, T; Seva, T; Thomas, L; Vander Velde, C; Vanlaer, P; Wang, J; Zenoni, F; Adler, V; Beernaert, K; Benucci, L; Cimmino, A; Costantini, S; Crucy, S; Dildick, S; Fagot, A; Garcia, G; Mccartin, J; Ocampo Rios, A A; Ryckbosch, D; Salva Diblen, S; Sigamani, M; Strobbe, N; Thyssen, F; Tytgat, M; Yazgan, E; Zaganidis, N; Basegmez, S; Beluffi, C; Bruno, G; Castello, R; Caudron, A; Ceard, L; Da Silveira, G G; Delaere, C; du Pree, T; Favart, D; Forthomme, L; Giammanco, A; Hollar, J; Jafari, A; Jez, P; Komm, M; Lemaitre, V; Nuttens, C; Pagano, D; Perrini, L; Pin, A; Piotrzkowski, K; Popov, A; Quertenmont, L; Selvaggi, M; Vidal Marono, M; Vizan Garcia, J M; Beliy, N; Caebergs, T; Daubie, E; Hammad, G H; Aldá Júnior, W L; Alves, G A; Brito, L; Correa Martins Junior, M; Dos Reis Martins, T; Mora Herrera, C; Pol, M E; Carvalho, W; Chinellato, J; Custódio, A; Da Costa, E M; De Jesus Damiao, D; De Oliveira Martins, C; Fonseca De Souza, S; Malbouisson, H; Matos Figueiredo, D; Mundim, L; Nogima, H; Prado Da Silva, W L; Santaolalla, J; Santoro, A; Sznajder, A; Tonelli Manganote, E J; Vilela Pereira, A; Bernardes, C A; Dogra, S; Fernandez Perez Tomei, T R; Gregores, E M; Mercadante, P G; Novaes, S F; Padula, Sandra S; Aleksandrov, A; Genchev, V; Iaydjiev, P; Marinov, A; Piperov, S; Rodozov, M; Stoykova, S; Sultanov, G; Vutova, M; Dimitrov, A; Glushkov, I; Hadjiiska, R; Kozhuharov, V; Litov, L; Pavlov, B; Petkov, P; Bian, J G; Chen, G M; Chen, H S; Chen, M; Du, R; Jiang, C H; Plestina, R; Romeo, F; Tao, J; Wang, Z; Asawatangtrakuldee, C; Ban, Y; Liu, S; Mao, Y; Qian, S J; Wang, D; Zhang, L; Zou, W; Avila, C; Chaparro Sierra, L F; Florez, C; Gomez, J P; Gomez Moreno, B; Sanabria, J C; Godinovic, N; Lelas, D; Polic, D; Puljak, I; Antunovic, Z; Kovac, M; Brigljevic, V; Kadija, K; Luetic, J; Mekterovic, D; Sudic, L; Attikis, A; Mavromanolakis, G; Mousa, J; Nicolaou, C; Ptochos, F; Razis, P A; Bodlak, M; Finger, M; Finger, M; Assran, Y; Ellithi Kamel, A; Mahmoud, M A; Radi, A; Kadastik, M; Murumaa, M; Raidal, M; Tiko, A; Eerola, P; Fedi, G; Voutilainen, M; Härkönen, J; Karimäki, V; Kinnunen, R; Kortelainen, M J; Lampén, T; Lassila-Perini, K; Lehti, S; Lindén, T; Luukka, P; Mäenpää, T; Peltola, T; Tuominen, E; Tuominiemi, J; Tuovinen, E; Wendland, L; Talvitie, J; Tuuva, T; Besancon, M; Couderc, F; Dejardin, M; Denegri, D; Fabbro, B; Faure, J L; Favaro, C; Ferri, F; Ganjour, S; Givernaud, A; Gras, P; Hamel de Monchenault, G; Jarry, P; Locci, E; Malcles, J; Rander, J; Rosowsky, A; Titov, M; Baffioni, S; Beaudette, F; Busson, P; Charlot, C; Dahms, T; Dalchenko, M; Dobrzynski, L; Filipovic, N; Florent, A; Granier de Cassagnac, R; Mastrolorenzo, L; Miné, P; Mironov, C; Naranjo, I N; Nguyen, M; Ochando, C; Paganini, P; Regnard, S; Salerno, R; Sauvan, J B; Sirois, Y; Veelken, C; Yilmaz, Y; Zabi, A; Agram, J-L; Andrea, J; Aubin, A; Bloch, D; Brom, J-M; Chabert, E C; Collard, C; Conte, E; Fontaine, J-C; Gelé, D; Goerlach, U; Goetzmann, C; Le Bihan, A-C; Van Hove, P; Gadrat, S; Beauceron, S; Beaupere, N; Boudoul, G; Bouvier, E; Brochet, S; Carrillo Montoya, C A; Chasserat, J; Chierici, R; Contardo, D; Depasse, P; El Mamouni, H; Fan, J; Fay, J; Gascon, S; Gouzevitch, M; Ille, B; Kurca, T; Lethuillier, M; Mirabito, L; Perries, S; Ruiz Alvarez, J D; Sabes, D; Sgandurra, L; Sordini, V; Vander Donckt, M; Verdier, P; Viret, S; Xiao, H; Tsamalaidze, Z; Autermann, C; Beranek, S; Bontenackels, M; Edelhoff, M; Feld, L; Hindrichs, O; Klein, K; Ostapchuk, A; Perieanu, A; Raupach, F; Sammet, J; Schael, S; Weber, H; Wittmer, B; Zhukov, V; Ata, M; Brodski, M; Dietz-Laursonn, E; Duchardt, D; Erdmann, M; Fischer, R; Güth, A; Hebbeker, T; Heidemann, C; Hoepfner, K; Klingebiel, D; Knutzen, S; Kreuzer, P; Merschmeyer, M; Meyer, A; Millet, P; Olschewski, M; Padeken, K; Papacz, P; Reithler, H; Schmitz, S A; Sonnenschein, L

    2015-02-13

    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at ?[s]=8??TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7??fb(-1). Events are selected with an electron and muon with opposite charges that both have transverse impact parameter values between 0.02 and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-? final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-? final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to c?=2??cm, excluding masses below 790 GeV at 95% confidence level. PMID:25723204

  12. Noise-Immune Conjugate Large-Area Atom Interferometers

    NASA Astrophysics Data System (ADS)

    Chiow, Sheng-Wey; Herrmann, Sven; Chu, Steven; Müller, Holger

    2009-07-01

    We present a pair of simultaneous conjugate Ramsey-Bordé atom interferometers using large (20?k)-momentum transfer beam splitters, where ?k is the photon momentum. Simultaneous operation allows for common-mode rejection of vibrational noise. This allows us to surpass the enclosed space-time area of previous interferometers with a splitting of 20?k by a factor of 2500. Using a splitting of 10?k, we demonstrate a 3.4 ppb resolution in the measurement of the fine structure constant. Examples for applications in tests of fundamental laws of physics are given.

  13. Search for Displaced Supersymmetry in events with an electron and a muon with large impact parameters

    E-print Network

    CMS Collaboration

    2015-02-17

    A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at sqrt(s) = 8 TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7 inverse femtobarns. Events are selected with an electron and a muon that have transverse impact parameter values between 0.02 cm and 2 cm. The search has been designed to be sensitive to a wide range of models with nonprompt e-mu final states. Limits are set on the "displaced supersymmetry" model, with pair production of top squarks decaying into an e-mu final state via R-parity-violating interactions. The results are the most restrictive to date on this model, with the most stringent limit being obtained for a top squark lifetime corresponding to c tau = 2 cm, excluding masses below 790 GeV at 95% confidence level.

  14. Continuum modeling of lattice structures in large displacement applications to buckling analysis

    Microsoft Academic Search

    G. Moreau; D. Caillerie

    1998-01-01

    We consider very large periodic trusses called lattice structures. In classical calculus, the periodic truss character and its global geometry are forgotten. With the homogenization method that we have developed, the lattice is replaced by a continuum model which approaches, in a certain sense, the real structure. This is true when the number of constitutive cells becomes large. The homogenization

  15. Experimental examination of wire mesh dampers subjected to large amplitude displacements

    E-print Network

    Jones, Adam Matthew

    2009-06-02

    the stability of the system. The objective of this research was to determine the properties of wire mesh dampers under large amplitude vibrations. Impact testing was first conducted on the wire mesh as a means of obtaining the large amplitudes that were...

  16. A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

    PubMed Central

    Choi, Jongsoo; Qiu, Zhen; Rhee, Choong-Ho; Wang, Thomas; Oldham, Kenn

    2014-01-01

    A novel three degree-of-freedom microactuator based on thin-film lead-zirconate-titanate (PZT) is described with its detailed structural model. Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for one corner of the stage. It has been developed to support real-time in vivo vertical cross-sectional imaging with a dual axes confocal endomicroscope for early cancer detection, having large displacements in three axes (z, ?x, ?y) and a relatively high bandwidth in the z-axis direction. Prototype microactuators closely meet the performance requirements for this application; in the out-of-plane (z-axis) direction, it has shown more than 177 ?m of displacement and about 84 Hz of structural natural frequency, when two diagonal legs are actuated at 14V. With all four legs, another prototype of the same design with lighter stage mass has achieved more than 430 ?m of out-of-plane displacement at 15V and about 200 Hz of bandwidth. The former design has shown approximately 6.4° and 2.9° of stage tilting about the x-axis and y-axis, respectively, at 14V. This paper also presents a modeling technique that uses experimental data to account for the effects of fabrication uncertainties in residual stress and structural dimensions. The presented model predicts the static motion of the stage within an average absolute error of 14.6 ?m, which approaches the desired imaging resolution, 5 ?m, and also reasonably anticipates the structural dynamic behavior of the stage. The refined model will support development of a future trajectory tracking controller for the system. PMID:25506131

  17. Achieving large stable vertical displacement in surface-micromachined microelectromechanical systems (MEMS)

    E-print Network

    Deutsch, Erik R. (Erik Robertson), 1974-

    2002-01-01

    This thesis describes electrostatic actuation techniques and mechanical design features for realizing large planar analog vertical travel in an electrostatically actuated diffractive mid-infrared optical device, which is ...

  18. Fast figuring of large optics by reactive atom plasma

    NASA Astrophysics Data System (ADS)

    Castelli, Marco; Jourdain, Renaud; Morantz, Paul; Shore, Paul

    2012-09-01

    The next generation of ground-based astronomical observatories will require fabrication and maintenance of extremely large segmented mirrors tens of meters in diameter. At present, the large production of segments required by projects like E-ELT and TMT poses time frames and costs feasibility questions. This is principally due to a bottleneck stage in the optical fabrication chain: the final figuring step. State-of-the-art figure correction techniques, so far, have failed to meet the needs of the astronomical community for mass production of large, ultra-precise optical surfaces. In this context, Reactive Atom Plasma (RAP) is proposed as a candidate figuring process that combines nanometer level accuracy with high material removal rates. RAP is a form of plasma enhanced chemical etching at atmospheric pressure based on Inductively Coupled Plasma technology. The rapid figuring capability of the RAP process has already been proven on medium sized optical surfaces made of silicon based materials. In this paper, the figure correction of a 3 meters radius of curvature, 400 mm diameter spherical ULE mirror is presented. This work demonstrates the large scale figuring capability of the Reactive Atom Plasma process. The figuring is carried out by applying an in-house developed procedure that promotes rapid convergence. A 2.3 ?m p-v initial figure error is removed within three iterations, for a total processing time of 2.5 hours. The same surface is then re-polished and the residual error corrected again down to ?/20 nm rms. These results highlight the possibility of figuring a metre-class mirror in about ten hours.

  19. Average square atomic displacement: A comparison of the lattice-dynamics, molecular-dynamics, and Monte Carlo results

    Microsoft Academic Search

    Gernot A. Heiser; Ramesh C. Shukla; E. R. Cowley

    1986-01-01

    Molecular-dynamics (MD) and Monte Carlo (MC) calculations of the mean-square displacement (MSD) have been carried out for a fcc nearest-neighbor Lennard-Jones model for a wide range of temperatures and lattice spacings. The lattice-dynamics (LD) calculations of the harmonic and the lowest-order anharmonic (cubic and quartic) contributions to the mean-square displacement were performed for the same potential model as in the

  20. Element-specific modal formulations for large-displacement multibody dynamics

    NASA Technical Reports Server (NTRS)

    Ryan, R. R.; Yoo, H. H.

    1989-01-01

    Large dispacement assumed-mode modeling techniques are examined in the context of multibody elastodynamics. The range of both general and element-specific approaches are studied with the aid of examples involving beams, plates, and shells. For systems undergoing primarily structural bending and twisting with little or no membrane distortion, it is found that fully-linear, element-specific, modal formulations provide the most accurate time history solutions at the least expense. When membrane effects become dominant in structural problems due to loading and boundary conditions, one must naturally resort to a formulation involving a nonlinear stress-strain relationship in addition to nonlinear terms associated with large overall system motion. Such nonlinear models were investigated using assumed modes and found to lead to modal convergence difficulties when standard free-free structural modes are employed. A constrained mode formulation aimed at addressing the convergence problem is proposed.

  1. XAFS and XRD Study of the Atomic Displacements in Aurivillius Phase Ferroelectric Bi2.25Ca0.5Na0.25Nb2O9

    SciTech Connect

    Vlasenko, Valery G.; Shuvaev, Anatoliy T.; Pirog, Irina V.; Drannikov, Dmitriy; Zarubin, Ivan A. [Research Institute of Physics, Rostov State University, pr. Stachki 194, Rostov-on-Don, 344090 (Russian Federation)

    2007-02-02

    The novel layered perovskite-like oxide with Aurivillius phase structure Bi2.25Ca0.5Na0.25Nb2O9 has been synthesized by solid-state reaction method. This compound is a ferroelectric with the Curie temperature 972 K. The crystal structure of Bi2.25Ca0.5Na0.25Nb2O9 has been determined from powder diffraction data recorded at room temperature. The parameters of the orthorhombic cell (space group A21am) are: a=5.4845 A, b=5.4549 A, c=24.9195 A. Using the profile of the X-ray diffraction pattern the atomic coordinates have been refined by Rietveld method and the Nb ion position in the oxygen octahedra has been found. It was shown that the Nb ion is displaced from the center of the oxygen octahedra by {approx}0.15 A. Nb K-edge EXAFS spectra were measured over the temperature range 295 K - 960 K. The interatomic distances Nb-O and the mean-square relative displacements {sigma}2 have been determined. The interatomic distances Nb-O at room temperature obtained from XAFS analysis are in a good agreement with those found from XRD data. It was revealed that the temperature increase results in the decreasing of Nb ion displacements from the center of the oxygen octahedra. However, in the vicinity of the ferroelectric phase transition the displacement of Nb ion was preserved.

  2. Performance Benefits of Large Execution Atomic Units in Dynamically Scheduled Machines

    E-print Network

    Melvin, Stephen

    Performance Benefits of Large Execution Atomic Units in Dynamically Scheduled Machines Stephen W In this paper we identify three types of atomic units, or indivisible units of work: archi- tectural atomic units (defitird by architec- ture level interrupts and exceptions). compiler atomic units (defined

  3. Displacement Field and Elastic Energy of a Circular Twist Disclination for Large Deformations - an Example how to Treat Nonlinear Boundary Value Problems with Computer Algebra Systems

    Microsoft Academic Search

    Alexander Unzicker; Karl Fabian

    2003-01-01

    A circular twist disclination is a nontrivial example of a defect in an elastic continuum that causes large deformations. The minimal potential energy and the corresponding displacement field is calculated by solving the Euler-Lagrange-equations. The nonlinear incompressibility constraint is rigorously taken into account. By using an appropriate curvilinear coordinate system a finer resolution in the regions of large deformations is

  4. Large Atomic Natural Orbital Basis Sets for the First Transition Row Atoms

    NASA Technical Reports Server (NTRS)

    Bauschlicher, Charles W., Jr.; Langhoff, Stephen R. (Technical Monitor)

    1994-01-01

    Large atomic natural orbital (ANO) basis sets are tabulated for the Sc to Cu. The primitive sets are taken from the large sets optimized by Partridge, namely (21s 13p 8d) for Sc and Ti and (20s 12p 9d) for V to Cu. These primitive sets are supplemented with three p, one d, six f, and four g functions. The ANO sets are derived from configuration interaction density matrices constructed as the average of the lowest states derived from the 3d(sup n)4s(sup 2) and 3d(sup n+1)4s(sup 1) occupations. For Ni, the 1S(3d(sup 10)) state is included in the averaging. The choice of basis sets for molecular calculations is discussed.

  5. Large spin relaxation rates in trapped submerged-shell atoms

    E-print Network

    Connolly, Colin B.

    Spin relaxation due to atom–atom collisions is measured for magnetically trapped erbium and thulium atoms at a temperature near 500 mK. The rate constants for Er–Er and Tm–Tm collisions are 3.0×10[superscript -10] and ...

  6. Air blast atomization using large air flow rates

    Microsoft Academic Search

    G. E. Andrews

    1989-01-01

    The 'jet mix' type interacting shear layer mixing flame stabilizer has been experimentally tested to ascertain combined air blast atomization and fuel\\/air mixing characteristics at gas turbine primary zone design conditions. Air blast atomization performance improves with increasing proportion of combustion airflow use for this purpose. Low Sauter mean diameter (SMD) values were achieved, but the atomization distribution deteriorated with

  7. On the use of crystal vibrational modes in the estimation of the anisotropic displacement parameters of hydrogen atoms in molecular crystals: para-Nitroaniline as a test case

    NASA Astrophysics Data System (ADS)

    Pozzi, C. Gustavo; Fantoni, Adolfo C.; Goeta, Andrés E.; de Matos Gomes, Etelvina; McIntyre, Garry J.; Punte, Graciela

    2013-09-01

    The use of crystal vibrational modes and frequencies calculated for the periodic system to complement a Translation Libration Screw (TLS) fit in the estimation of anisotropic displacement parameters (ADPs) of hydrogen atoms in molecular crystals is proposed. As a test case we have used the para-nitroaniline crystal, for which a reference set of ADPs has been obtained by performing a single crystal neutron diffraction study at 100 K. Although the largest difference between estimated and experimental reference values amounts to 0.06 Å2, this value being about six times the experimental uncertainty, the agreement is better than three experimental uncertainties for 33 out of the total of 36 ADPs. The performance of the suggested method, particularly for the amino atoms, is thoroughly analyzed.

  8. How Large are Nonadiabatic Effects in Atomic and Diatomic Systems?

    E-print Network

    Yang, Yubo; Tubman, Norm; Krogel, Jaron; Hammes-Schiffer, Sharon; Ceperley, David

    2015-01-01

    With recent developments in simulating nonadiabatic systems to high accuracy, it has become possible to determine how much energy is attributed to nuclear quantum effects beyond zero-point energy. In this work we calculate the non-relativistic ground-state energies of atomic and molecular systems without the Born-Oppenheimer approximation. For this purpose we utilize the fixed-node diffusion Monte Carlo method, in which the nodes depend on both the electronic and ionic positions. We report ground-state energies for all systems studied, ionization energies for the first-row atoms and atomization energies for the first-row hydrides. We find the ionization energies of the atoms to be nearly independent of the Born-Oppenheimer approximation, within the accuracy of our results. The atomization energies of molecular systems, however, show small effects of the nonadiabatic coupling between electrons and nuclei.

  9. Neutron scattering studies of short-range order and atomic displacements in a null-matrix nickel-62 platinum crystal

    NASA Astrophysics Data System (ADS)

    Rodriguez, Jose Abelardo

    The best known exception to the Heine-Samson and Bieber-Gautier arguments for ordering effects in transition metal alloys (similar to the Hume-Rothery rules) is a NiPt alloy, where the phase diagram is similar to the CuAu system. Using the Disk Chopper Spectrometer (DCS) at NIST, we have investigated a Null-Matrix Crystal 62 Ni0.52Pt0.48, (62 Ni has a negative scattering length, nearly equal in magnitude to Pt). Its composition has therefore been chosen whereby all effects depending on the average lattice scattering vanish. The only remaining contributions to the diffuse scattering are the Short Range Order (SRO) and Size Effect (SE) terms, to be discussed within. Such data permit the extraction of the SRO parameters (concentration-concentration correlations) as well as the displacement parameters (concentration-displacement correlations). Using the Krivoglaz-Clapp-Moss theory, we obtained the Effective Pair Interactions (EPI) between the several neighbors in the alloy. The results can be used to model the alloy in the context of electronic theory of alloy phase stability, including an evaluation of the potentially important aspect of charge transfer and ionicity.

  10. Where the atoms are: Cation disorder and anion displacement in D IIX VI-A IB IIIX VI2 semiconductors

    NASA Astrophysics Data System (ADS)

    Schorr, Susan; Tovar, Michael; Stuesser, Norbert; Sheptyakov, Denis; Geandier, Guillaume

    2006-11-01

    Structural phase transitions (tetragonal-cubic) dependent on composition as well as temperature were studied in ternary CuB IIIX 2 chalcopyrites as well as 2(ZnX) x(CuInX 2) 1-x alloys (B=Ga, In; X=S, Se, Te) by neutron and synchrotron X-ray powder diffraction. The transitions are due to a combination of disorder of the cation sublattice and displacement of the anion sublattice. The first goes along with a phase separation by chemical disorder, within a homologeous series depending on the size of the anion, for the same anion depending on the size of cation B. The temperature-dependent phase transition is clearly driven by a Cu-B anti-site occupancy. The order parameter of the phase transition, expressed as a difference in the number of electrons on the cation sites in the disordered and ordered phase, shows a critical behaviour with a critical exponent ?=0.35(7).

  11. Ionization Potentials in the Limit of Large Atomic Number

    NASA Astrophysics Data System (ADS)

    Snyder, John C.

    By extrapolating the energies of non-relativistic atoms and their ions with up to 3000 electrons within Kohn-Sham density functional theory, we find that the ionization potential remains finite and increases across a row, even as Z goes to infinity. The local density approximation for the exchange contribution becomes more accurate (or even exact) in this limit. Extended Thomas-Fermi theory matches the shell-average of both the ionization potential and density change.

  12. Optically trapped atom interferometry using the clock transition of large Rb BoseEinstein

    E-print Network

    Queensland, University of

    Optically trapped atom interferometry using the clock transition of large 87 Rb Bose f o r p h y s i c s New Journal of Physics Optically trapped atom interferometry using the clock us to couple the |F = 1, mF = 0 |F = 2, mF = 0 clock states using a single photon 6.8 GHz microwave

  13. Behavior of the chemical potential of neutral atoms in the limit of large nuclear charge

    Microsoft Academic Search

    José Luis Gázquez; Alberto Vela; Marcelo Galván

    1986-01-01

    It is shown that in the limit of large nuclear charge Z, the chemical potential of a neutral atom is given by mu~Z-1\\/3X periodic function of Z1\\/3. This expression accounts for the general behavior of the chemical potential of atoms in the Periodic Table.

  14. Air blast atomization as a function of pressure loss for large air flow rates

    Microsoft Academic Search

    G. E. Andrews

    1990-01-01

    Combined air blast atomization and fuel and air mixing was studied in an interacting shear layer jet mixing flame stabilizer, termed Jet Mix, at gas turbine primary zone design conditions. Air blast atomization improves if large proportions of the combustion air flow are used and the maximum possible airflows were used in this study, as all the primary zone air

  15. Atomic-order thermal nitridation of group IV semiconductors for ultra-large-scale integration

    NASA Astrophysics Data System (ADS)

    Murota, Junichi; Le Thanh, Vinh

    2015-03-01

    One of the main requirements for ultra-large-scale integration (ULSI) is atomic-order control of process technology. Our concept of atomically controlled processing for group IV semiconductors is based on atomic-order surface reaction control in Si-based CVD epitaxial growth. On the atomic-order surface nitridation of a few nm-thick Ge/about 4 nm-thick Si0.5Ge0.5/Si(100) by NH3, it is found that N atoms diffuse through nm-order thick Ge layer into Si0.5Ge0.5/Si(100) substrate and form Si nitride, even at 500 °C. By subsequent H2 heat treatment, although N atomic amount in Ge layer is reduced drastically, the reduction of the Si nitride is slight. It is suggested that N diffusion in Ge layer is suppressed by the formation of Si nitride and that Ge/atomic-order N layer/Si1?xGex/Si (100) heterostructure is formed. These results demonstrate the capability of CVD technology for atomically controlled nitridation of group IV semiconductors for ultra-large-scale integration. Invited talk at the 7th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2014, 2-6 November, 2014, Ha Long, Vietnam.

  16. Fission-fusion correlations for swelling and microstructure in stainless steels: effect of the helium-to-displacement-per-atom ratio

    SciTech Connect

    Odette, G.R.; Maziaz, P.J.; Spitznagel, J.A.

    1981-01-01

    The initial irradiated structural materials data base for fusion applications will be developed in fission reactors. Hence, this data may need to be adjusted using physically-based procedures to represent behavior in fusion environments, viz. - fission-fusion correlations. Such correlation should reflect a sound mechanistic understanding, and be verified in facilities which most closely simulate fusion conditions. In this paper we review the effects of only one of a number of potentially significant damage variables, the helium to displacement per atom ratio, on microstructural evolution in austenitic stainless steels. Dual-ion and helium preinjection data are analyzed to provide mechanistic guidance; these results appear to be qualitatively consistent with a more detailed comparison made between fast (EBR-II) and mixed (HFIR) spectrum neutron data for a single heat of 20% cold-worked 316 stainless steel. These two fission environments bound fusion (He/dpa ratios. A model calibrated to the fission reactor data is used to extrapolate to fusion conditions. Both the theory and broad empirical observation suggest that helium to dpa ratios have both a qualitative and quantitative influence on microstructural evolution; and that the very high and low ratios found in HFIR and EBR-II may not result in behavior which brackets intermediate fusion conditions.

  17. Dynamics and thermodynamics of crystalline polymorphs. 3. ?-Glycine, analysis of variable-temperature atomic displacement parameters, and comparison of polymorph stabilities.

    PubMed

    Aree, Thammarat; Bürgi, Hans-Beat; Chernyshov, Dmitry; Törnroos, Karl W

    2014-10-30

    In a series of systematic studies, we have investigated the molecular motion in crystals of the glycine polymorphs and determined their thermodynamic functions from an analysis of multitemperature atomic displacement parameters (ADPs) combined with ONIOM calculation on 15-molecule clusters. The studies are aimed at providing insight into the factors governing the relative stabilities of the ?-, ?-, and ?-polymorphs. This Article, the last in the series, focuses on the most stable polymorph, ?-glycine. Multitemperature diffraction data of the ?-glycine polymorph have been collected to 0.5 Å resolution between 10 and 300 K at two synchrotron beamlines, KEK Photon Factory and ID11 of the ESRF. The ADPs of ?-glycine from these sources differ significantly, as previously observed also for the other two polymorphs. A simple model of rigid body motion explains the ADPs from KEK and their temperature dependence. It provides lattice vibration frequencies that are in line with those from Raman spectroscopy. Together with the internal vibration frequencies from an ONIOM calculation, the thermodynamic functions are estimated using the Einstein, Debye, and Nernst-Lindemann models of heat capacity. The relative stabilities of the three polymorphs of glycine are discussed on the basis of the contributions to their free energies as obtained in this work and from various experimental and theoretical studies. The comparison shows that the free-energy differences are determined primarily by differences in lattice and zero-point vibrational energies. PMID:25271763

  18. Influence of static atomic displacements on composition quantification of AlGaN/GaN heterostructures from HAADF-STEM images.

    PubMed

    Schowalter, Marco; Stoffers, Ingo; Krause, Florian F; Mehrtens, Thorsten; Müller, Knut; Fandrich, Malte; Aschenbrenner, Timo; Hommel, Detlef; Rosenauer, Andreas

    2014-10-01

    In an earlier publication Rosenauer et al. introduced a method for determination of composition in AlGaN/GaN heterostructures from high-angle annular dark field (HAADF) images. Static atomic displacements (SADs) were neglected during simulation of reference data because of the similar covalent radii of Al and Ga. However, SADs have been shown (Grillo et al.) to influence the intensity in HAADF images and therefore could be the reason for an observed slight discrepancy between measured and nominal concentrations. In the present study parameters of the Stillinger-Weber potential were varied in order to fit computed elastic constants, lattice parameters and bonding energies to experimental ones. A reference data set of HAADF images was simulated, in which the new parameterization was used to account for SADs. Two reference samples containing AlGaN layers with different Al concentrations were investigated and Al concentrations in the layers determined based on the new data set. We found that these concentrations were in good agreement with nominal concentrations as well as concentrations determined using alternative techniques such as strain state analysis and energy dispersive X-ray spectroscopy. PMID:25010567

  19. Contrasting styles of large-scale displacement of unconsolidated sand: examples from the early Jurassic Navajo Sandstone on the Colorado Plateau, USA

    NASA Astrophysics Data System (ADS)

    Bryant, Gerald

    2015-04-01

    Large-scale soft-sediment deformation features in the Navajo Sandstone have been a topic of interest for nearly 40 years, ever since they were first explored as a criterion for discriminating between marine and continental processes in the depositional environment. For much of this time, evidence for large-scale sediment displacements was commonly attributed to processes of mass wasting. That is, gravity-driven movements of surficial sand. These slope failures were attributed to the inherent susceptibility of dune sand responding to environmental triggers such as earthquakes, floods, impacts, and the differential loading associated with dune topography. During the last decade, a new wave of research is focusing on the event significance of deformation features in more detail, revealing a broad diversity of large-scale deformation morphologies. This research has led to a better appreciation of subsurface dynamics in the early Jurassic deformation events recorded in the Navajo Sandstone, including the important role of intrastratal sediment flow. This report documents two illustrative examples of large-scale sediment displacements represented in extensive outcrops of the Navajo Sandstone along the Utah/Arizona border. Architectural relationships in these outcrops provide definitive constraints that enable the recognition of a large-scale sediment outflow, at one location, and an equally large-scale subsurface flow at the other. At both sites, evidence for associated processes of liquefaction appear at depths of at least 40 m below the original depositional surface, which is nearly an order of magnitude greater than has commonly been reported from modern settings. The surficial, mass flow feature displays attributes that are consistent with much smaller-scale sediment eruptions (sand volcanoes) that are often documented from modern earthquake zones, including the development of hydraulic pressure from localized, subsurface liquefaction and the subsequent escape of fluidized sand toward the unconfined conditions of the surface. The origin of the forces that produced the lateral, subsurface movement of a large body of sand at the other site is not readily apparent. The various constraints on modeling the generation of the lateral force required to produce the observed displacement are considered here, along with photodocumentation of key outcrop relationships.

  20. Theory of a compound large-angle atom beam splitter. II. Initial state deflection

    SciTech Connect

    Muradyan, A.Zh.; Muradyan, G.A.; Berman, P.R. [Department of Physics, Yerevan State University, 1 Alex Manookian, Yerevan 375025 (Armenia); Michigan Center for Theoretical Physics, FOCUS Center, and Department of Physics, University of Michigan, Ann Arbor, Michigan 48109-1012 (United States)

    2004-12-01

    The theory of a compound, large-angle atom beam splitter [A. Zh. Muradyan, A. A. Poghosyan, and P. R. Berman, Phys. Rev. A 68, 033604 (2003)] is generalized to allow for initial-state deflection. Atoms are prepared in an initial state by an off-resonant standing-wave field and then subject to two-standing-wave fields that couple the initial state to a final state. By a proper choice of parameters, atoms in the initial state can be deflected or split as a result of the interactions with the fields. The role of relaxation is considered.

  1. Light self-trapping in a large cloud of cold atoms.

    PubMed

    Labeyrie, Guillaume; Bortolozzo, Umberto

    2011-06-01

    We show that, for a near-resonant propagating beam, a large cloud of cold Rb87 atoms acts as a saturable Kerr medium and produces self-trapping of light. By side fluorescence imaging, we monitor the transverse size of the beam and, depending on the sign of the laser detuning with respect to the atomic transition, we observe self-focusing or self-defocusing, with the waist remaining stationary for an appropriate choice of parameters. We analyze our observations by using numerical simulations based on a simple two-level atom model. PMID:21633481

  2. Low spring index, large displacement Shape Memory Alloy (SMA) coil actuators for use in macro- and micro-systems

    E-print Network

    Newman, Dava

    Shape memory alloys (SMA) offer unique shape changing characteristics that can be exploited to produce low­ mass, low-bulk, large-stroke actuators. We are investigating the use of low spring index (defined as the ratio of ...

  3. Optimization of evaporative cooling towards a large number of Bose-Einstein-condensed atoms

    SciTech Connect

    Yamashita, Makoto; Mukai, Tetsuya; Mukai, Takaaki [NTT Basic Research Laboratories, NTT Corporation, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Koashi, Masato [Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240-0193 (Japan); Mitsunaga, Masaharu [Faculty of Science, Department of Physics, Kumamoto University, 2-39-1, Kurokami, Kumamoto 860-8555 (Japan); Imoto, Nobuyuki [NTT Basic Research Laboratories, NTT Corporation, 3-1, Morinosato Wakamiya, Atsugi-shi, Kanagawa 243-0198 (Japan); Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240-0193 (Japan)

    2003-02-01

    We study the optimization of evaporative cooling in trapped bosonic atoms on the basis of quantum kinetic theory of a Bose gas. The optimized cooling trajectory for {sup 87}Rb atoms indicates that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against loss of trapped atoms caused by three-body recombination. The number of condensed atoms is largely enhanced by the optimization, more than two orders of magnitude in our present calculation using relevant experimental parameters, as compared with the typical value given by the conventional evaporative cooling where the frequency of radio-frequency magnetic field is swept exponentially. In addition to this optimized cooling, it is also shown that highly efficient evaporative cooling can be achieved by an initial exponential and then a rapid linear sweep of frequency.

  4. Optimization of evaporative cooling towards a large number of Bose-Einstein condensed atoms

    E-print Network

    Makoto Yamashita; Masato Koashi; Tetsuya Mukai; Masaharu Mitsunaga; Nobuyuki Imoto; Takaaki Mukai

    2002-12-17

    We study the optimization of evaporative cooling in trapped bosonic atoms on the basis of quantum kinetic theory of a Bose gas. The optimized cooling trajectory for $^{87}$Rb atoms indicates that the acceleration of evaporative cooling around the transition point of Bose-Einstein condensation is very effective against loss of trapped atoms caused by three-body recombination. The number of condensed atoms is largely enhanced by the optimization, more than two orders of magnitude in our present calculation using relevant experimental parameters, as compared with the typical value given by the conventional evaporative cooling where the frequency of radio-frequency magnetic field is swept exponentially. In addition to this optimized cooling, it is also shown that highly efficient evaporative cooling can be achieved by an initial exponential and then a rapid linear sweep of frequency.

  5. Resonance Phenomena in Large-Angle Helium Ion-Helium Atom Collisions

    Microsoft Academic Search

    F. P. Ziemba; E. Everhart

    1959-01-01

    When He\\/sup +\\/ ions are scattered from He atoms at kev energies, a small ; fraction of thesc collisions results in large-angle scattering of the incident ; particle. Particles from He\\/sup +\\/-He collisions were analyzed to determine the ; fractions which were neutral and doubly ionized. These data are shown ; graphically. (A.C.);

  6. Measuring vulnerability to disaster displacement

    NASA Astrophysics Data System (ADS)

    Brink, Susan A.; Khazai, Bijan; Power, Christopher; Wenzel, Friedemann

    2015-04-01

    Large scale disasters can cause devastating impacts in terms of population displacement. Between 2008 and 2013, on average 27 million people were displaced annually by disasters (Yonetani 2014). After large events such as hurricane Katrina or the Port-au-Prince earthquake, images of inadequate public shelter and concerns about large scale and often inequitable migration have been broadcast around the world. Population displacement can often be one of the most devastating and visible impacts of a natural disaster. Despite the importance of population displacement in disaster events, measures to understand the socio-economic vulnerability of a community often use broad metrics to estimate the total socio-economic risk of an event rather than focusing on the specific impacts that a community faces in a disaster. Population displacement is complex and multi-causal with the physical impact of a disaster interacting with vulnerability arising from the response, environmental issues (e.g., weather), cultural concerns (e.g., expectations of adequate shelter), and many individual factors (e.g., mobility, risk perception). In addition to the complexity of the causes, population displacement is difficult to measure because of the wide variety of different terms and definitions and its multi-dimensional nature. When we speak of severe population displacement, we may refer to a large number of displaced people, an extended length of displacement or associated difficulties such as poor shelter quality, risk of violence and crime in shelter communities, discrimination in aid, a lack of access to employment or other difficulties that can be associated with large scale population displacement. We have completed a thorough review of the literature on disaster population displacement. Research has been conducted on historic events to understand the types of negative impacts associated with population displacement and also the vulnerability of different groups to these impacts. We aggregate these ideas into a framework of disaster displacement vulnerability that distinguishes between three main aspects of disaster displacement. Disaster displacement can be considered in terms of the number of displaced people and the length of that displacement. However, the literature emphasizes that the severity of disaster displacement can not be measured completely in quantitative terms. Thus, we include a measure representing people who are trapped and unable to leave their homes due to mobility, resources or for other reasons. Finally the third main aspect considers the difficulties that are associated with displacement and reflects the difference between the experiences of those who are displaced into safe and supportive environments as compared to those whose only alternate shelter is dangerous and inadequate for their needs. Finally, we apply the framework to demonstrate a methodology to estimate vulnerability to disaster displacement. Using data from the Global Earthquake Model (GEM) Social and Economic Vulnerability sub-National Database, we generate an index to measure the vulnerability of Japanese prefectures to the dimensions of displacement included in the framework. References Yonitani, M. (2014). Global Estimates 2014: People displaced by disasters. http://www.internal-displacement.org/publications/2014/global-estimates-2014-people-displaced-by-disasters/

  7. Large area growth and electrical properties of p-type WSe2 atomic layers.

    PubMed

    Zhou, Hailong; Wang, Chen; Shaw, Jonathan C; Cheng, Rui; Chen, Yu; Huang, Xiaoqing; Liu, Yuan; Weiss, Nathan O; Lin, Zhaoyang; Huang, Yu; Duan, Xiangfeng

    2015-01-14

    Transition metal dichacogenides represent a unique class of two-dimensional layered materials that can be exfoliated into single or few atomic layers. Tungsten diselenide (WSe(2)) is one typical example with p-type semiconductor characteristics. Bulk WSe(2) has an indirect band gap (? 1.2 eV), which transits into a direct band gap (? 1.65 eV) in monolayers. Monolayer WSe(2), therefore, is of considerable interest as a new electronic material for functional electronics and optoelectronics. However, the controllable synthesis of large-area WSe(2) atomic layers remains a challenge. The studies on WSe(2) are largely limited by relatively small lateral size of exfoliated flakes and poor yield, which has significantly restricted the large-scale applications of the WSe(2) atomic layers. Here, we report a systematic study of chemical vapor deposition approach for large area growth of atomically thin WSe(2) film with the lateral dimensions up to ? 1 cm(2). Microphotoluminescence mapping indicates distinct layer dependent efficiency. The monolayer area exhibits much stronger light emission than bilayer or multilayers, consistent with the expected transition to direct band gap in the monolayer limit. The transmission electron microscopy studies demonstrate excellent crystalline quality of the atomically thin WSe(2). Electrical transport studies further show that the p-type WSe(2) field-effect transistors exhibit excellent electronic characteristics with effective hole carrier mobility up to 100 cm(2) V(-1) s(-1) for monolayer and up to 350 cm(2) V(-1) s(-1) for few-layer materials at room temperature, comparable or well above that of previously reported mobility values for the synthetic WSe(2) and comparable to the best exfoliated materials. PMID:25434747

  8. Large Faraday rotation of resonant light in a cold atomic cloud

    E-print Network

    Labeyrie, G; Kaiser, R

    2001-01-01

    We experimentally studied the Faraday rotation of resonant light in an optically-thick cloud of laser-cooled rubidium atoms. Measurements yield a large Verdet constant in the range of 200 000 degrees/T/mm and a maximal polarization rotation of 150 degrees. A complete analysis of the polarization state of the transmitted light was necessary to account for the role of the probe laser's spectrum.

  9. Large-scale circulation of atomic oxygen in the upper mesosphere and lower thermosphere

    NASA Astrophysics Data System (ADS)

    Shepherd, Gordon G.; Liu, Guiping; Roble, Raymond G.

    The variability of the atomic oxygen green line airglow at 557.7 nm, originating from the O( 1S) level, has a long history of observation. Only recently, global observations of the oxygen airglow, interpreted with the help of global circulation models have provided some understanding. Satellite observations of winds and temperatures clearly demonstrate the dynamical influence of tides on the daily variations. Both annual and semi-annual components of the variation have been identified as occurring over the course of the year. From the large-scale circulation of the atmosphere one expects downwelling in the winter at high latitudes, causing enhanced atomic oxygen and enhanced airglow while the opposite is expected in summer. In the present investigation a search is made for this large-scale signature using data from the WIND Imaging Interferometer on the Upper Atmosphere Research Satellite, model results from the Thermosphere-Ionosphere-Mesosphere-Electrodynamics-Global Circulation Model, and earlier published results. A well-defined semi-annual variation of emission rate is found in the tropics, apparently the result of the semi-annual variation of the diurnal tide. Annual and semi-annual patterns are found at mid-latitudes, in satellite and model data, while ground-based observations detect only an annual variation, with a maximum in the autumn. At still higher latitudes the fall peak persists, but with a deep depletion of atomic oxygen in the springtime; this appears to be the signature of the large-scale circulation.

  10. Large Deviations, Central Limit and dynamical phase transitions in the atom maser

    E-print Network

    Merlijn van Horssen; Madalin Guta

    2013-10-14

    The theory of quantum jump trajectories provides a new framework for understanding dynamical phase transitions in open systems. A candidate for such transitions is the atom maser, which for certain parameters exhibits strong intermittency in the atom detection counts, and has a bistable stationary state. Although previous numerical results suggested that the "free energy" may not be a smooth function, we show that the atom detection counts satisfy a large deviations principle, and therefore we deal with a phase cross-over rather than a genuine phase transition. We argue however that the latter occurs in the limit of infinite pumping rate. As a corollary, we obtain the Central Limit Theorem for the counting process. The proof relies on the analysis of a certain deformed generator whose spectral bound is the limiting cumulant generating function. The latter is shown to be smooth, so that a large deviations principle holds by the Gartner-Ellis Theorem. One of the main ingredients is the Krein-Rutman Theorem which extends the Perron-Frobenius theory to a general class of positive compact semigroups.

  11. Large area hexagonal boron nitride monolayer as efficient atomically thick insulating coating against friction and oxidation.

    PubMed

    Li, Xuemei; Yin, Jun; Zhou, Jianxin; Guo, Wanlin

    2014-03-14

    Coating is the most widely applied technology to improve surface properties of substrates, and nanotechnology has been playing an important role in enhancing the coating performance. However, the tunability of surface properties by a single atomic layer remains poorly understood. Here we demonstrate that a chemical vapor deposited hexagonal boron nitride (h-BN) monolayer of large area and high quality can serve as a perfect coating to significantly improve friction, oxidation and electric resistance of the substrates. The exceptional low friction and insulation of h-BN monolayer coating facilitate the characterization of the h-BN film vividly by atomic force microscopy, showing the h-BN monolayer consists of domains with size within a few micrometers. This excellent coating performance together with the exceptional high thermal and chemical stability make the h-BN monolayer a promising coating material. PMID:24532053

  12. Single atom-scale diamond defect allows large Aharonov-Casher phase

    E-print Network

    D. Maclaurin; A. D. Greentree; J. H. Cole; L. C. L. Hollenberg; A. M. Martin

    2009-10-22

    We propose an experiment that would produce and measure a large Aharonov-Casher (A-C) phase in a solid-state system under macroscopic motion. A diamond crystal is mounted on a spinning disk in the presence of a uniform electric field. Internal magnetic states of a single NV defect, replacing interferometer trajectories, are coherently controlled by microwave pulses. The A-C phase shift is manifested as a relative phase, of up to 17 radians, between components of a superposition of magnetic substates, which is two orders of magnitude larger than that measured in any other atom-scale quantum system.

  13. (Atomic physics with large electrostatic accelerators): Foreign trip report, May 14, 1989--June 9, 1989

    SciTech Connect

    Datz, S.

    1989-06-12

    The traveler attended the First International Symposium on Swift Heavy Ions in Matter (SHIM '89) in Caen, France, and presented a paper on ''Dielectronic and Direct Excitation of Channeled Ions.'' He then participated in the 5th International Conference on Electrostatic Accelerators and Associated Boosters (Strasbourg, France, and Heidelberg, West Germany) and presented an invited lecture on ''Atomic Physics with Large Electrostatic Accelerators.'' The traveler visited the University of Aarhus (Denmark), where discussions were held on the present status of ASTRID; forthcoming collaborative experiments at CERN; dielectronic and radiative recombination experiments; charge dependence of double excitation and excitation-ionization collisions in helium; and crystal preparation for ORNL experiments in channeling.

  14. Single atom-scale diamond defect allows a large Aharonov-Casher phase

    SciTech Connect

    Maclaurin, D.; Hollenberg, L. C. L. [School of Physics, University of Melbourne, Parkville 3010 (Australia); Centre for Quantum Computer Technology, School of Physics, University of Melbourne, Parkville 3010 (Australia); Greentree, A. D.; Martin, A. M. [School of Physics, University of Melbourne, Parkville 3010 (Australia); Cole, J. H. [Institut fuer Theoretische Festkoerperphysik und DFG-Center for Functional Nanostructures (CFN), Universitaet Karlsruhe, 76128 Karlsruhe (Germany)

    2009-10-15

    We propose an experiment that would produce and measure a large Aharonov-Casher (AC) phase in a solid-state system under macroscopic motion. A diamond crystal is mounted on a spinning disk in the presence of a uniform electric field. Internal magnetic states of a single nitrogen-vacancy (N-V) defect, replacing interferometer trajectories, are coherently controlled by microwave pulses. The AC phase shift is manifested as a relative phase, of up to 17 radians, between components of a superposition of magnetic substates, which is two orders of magnitude larger than that measured in any other atom-scale quantum system.

  15. Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM) 

    E-print Network

    Verde Salas, Alexander José

    2014-04-28

    during injection and production operations. The Displacement Discontinuity Method (DDM) is frequently used for modeling the behavior of fractures embedded in elastic and poroelastic rocks. However, DDM requires the calculation of the influence among all...

  16. Enhancement of magneto-optic effects via large atomic coherence in optically dense media RID B-9041-2008 

    E-print Network

    Sautenkov, V. A.; Lukin, M. D.; Bednar, CJ; Novikova, I.; Mikhailov, E.; Fleischhauer, M.; Velichansky, V. L.; Welch, George R.; Scully, Marlan O.

    2000-01-01

    We utilize the generation of large atomic coherence in optically dense media to enhance the resonant nonlinear magneto-optic effect by several orders of magnitude, thereby eliminating power broadening and improving the fundamental signal...

  17. Large Faraday rotation of resonant light in a cold atomic cloud G. Labeyrie, C. Miniatura, and R. Kaiser

    E-print Network

    Kaiser, Robin

    light in an optically thick cloud of laser-cooled rubidium atoms. Measurements yield a large Verdet constant in the range of 105 °/T mm and a maximal polarization rotation of 150°. A complete analysis

  18. Enhancement of magneto-optic effects via large atomic coherence in optically dense media RID B-9041-2008

    E-print Network

    Sautenkov, V. A.; Lukin, M. D.; Bednar, CJ; Novikova, I.; Mikhailov, E.; Fleischhauer, M.; Velichansky, V. L.; Welch, George R.; Scully, Marlan O.

    2000-01-01

    and applied physics include the search for parity viola- tions @3?5# and optical magnetometry. In this paper, we demonstrate that the large atomic coherence associated with electromagnetically induced transparency ~EIT! @6,7# in op- tically thick samples...

  19. A large-sample atomic force microscope observing in both air and liquid.

    PubMed

    Fu, Xia; Zhang, Dongxian; Zhang, Haijun; Xie, Zhigang

    2011-11-01

    A large-sample atomic force microscope (AFM) that allows high resolution observation in both air and liquid has been developed. With a unique beam tracking method, laser beam is capable of reflecting off the same spot on the AFM cantilever throughout raster scan over the entire scan area, either operating in air or in liquid environment. Incorporating the stand-alone AFM probe unit with an automated large sample stage, wide-scan-range imaging can be realized with high resolution and slight distortion. In addition, an image stitching method is utilized to build a broad merged image with range up to millimeters while keeping nanometer order resolution. By using a large-volume liquid bath, large and massive sample can be observed in liquid with this AFM system. Several typical experiments have been carried out to demonstrate the imaging ability and stability of this AFM. Topographic structures of gold pattern on a glass substrate are scanned at two different places on the same specimen surface. The porosity of a sheet of filter paper is then characterized in both air and water. Finally, larger-area AFM image of anodic aluminum oxide template in oxalic acid is on spot obtained by merging several individually scanned images together. Experiments show that this AFM system can offer high resolution and wide range AFM images even for large samples with remarkable capabilities in various environments. PMID:21484944

  20. Modeling optical properties of silicon clusters by first principles: From a few atoms to large nanocrystals

    NASA Astrophysics Data System (ADS)

    Nurbawono, Argo; Liu, Shuanglong; Zhang, Chun

    2015-04-01

    Time dependent density functional tight binding (TDDFTB) method is implemented with sparse matrix techniques and improved parallelization algorithms. The method is employed to calculate the optical properties of various Si nanocrystals (NCs). The calculated light absorption spectra of small Si NCs from TDDFTB were found to be comparable with many body perturbation methods utilizing planewave basis sets. For large Si NCs (more than a thousand atoms) that are beyond the reach of conventional approaches, the TDDFTB method is able to produce reasonable results that are consistent with prior experiments. We also employed the method to study the effects of surface chemistry on the optical properties of large Si NCs. We learned that the optical properties of Si NCs can be manipulated with small molecule passivations such as methyl, hydroxyl, amino, and fluorine. In general, the shifts and profiles in the absorption spectra can be tuned with suitably chosen passivants.

  1. Calculations of atomic sputtering and displacement cross-sections in solid elements by electrons with energies from threshold to 1. 5 MV

    SciTech Connect

    Bradley, C.R.

    1988-12-01

    The kinetics of knock-on collisions of relativistic electrons with nuclei and details of the numerical evaluation of differential, recoil, and total Mott cross-sections are reviewed and discussed. The effects of electron beam induced displacement and sputtering, in the transmission electron microscope (TEM) environment, on microanalysis are analyzed with particular emphasis placed on the removal of material by knock-on sputtering. The mass loss predicted due to transmission knock-on sputtering is significant for many elements under conditions frequently encountered in microanalysis. Total Mott cross-sections are tabulated for all naturally occurring solid elements up to Z = 92 at displacement energies of one, two, four, and five times the sublimation energy and for accelerating voltages accessible in the transmission electron microscope. Fortran source code listings for the calculation of the differential Mott cross-section as a function of electron scattering angle (dMottCS), as a function of nuclear recoil angle (RECOIL), and the total Mott cross-section (TOTCS) are included. 48 refs., 21 figs., 12 tabs.

  2. The large-scale atomic and molecular gas in the Circinus galaxy

    NASA Astrophysics Data System (ADS)

    Curran, S. J.; Koribalski, B. S.; Bains, I.

    2008-09-01

    We have used the Australia Telescope Compact Array (ATCA) and the Swedish-ESO Submillimetre Telescope (SEST) to map the large-scale atomic and molecular gas in the nearby (4Mpc) Circinus galaxy. The ATCA HI mosaic of Circinus exhibits the warps in position angle and inclination revealed in the single-pointing image of Jones et al., both of which appear to settle beyond the inner 30kpc which was previously imaged. The molecular gas has been mapped in both the CO J = 1 -> 0 and J = 2 -> 1 transitions down to a column density of (3?), where we derive a total molecular gas mass of . Within a radius of 3kpc, i.e. where CO was clearly detected, the molecular fraction climbs steeply from ~ 0.7 to unity (where , cf. NHI = 1021cm-2) with proximity to the nucleus. Our HI mosaic gives an atomic gas mass of MHI ~ 6 × 109Msolar, which is 70 per cent of the fully mapped single dish value. Combining the atomic and molecular gas masses gives a total gas mass of , cf. the total dynamical mass of ~ 3 × 1011Msolar within the inner 50kpc of our mosaiced image. The total neutral gas mass to dynamical mass ratio is therefore 3 per cent, consistent with the SAS3 (Third Small Astronomy Satellite) classification of Circinus. The high (molecular) gas mass fraction of per cent found by Curran et al., only occurs close to the central ~ 0.5kpc and falls to <~10 per cent within and outwith this region, allaying previous concerns regarding the validity of applying the Galactic conversion ratio to Circinus. The rotation curve, as traced by both the HI and CO, exhibits a steep dip at ~ 1kpc, the edge of the atomic/molecular ring, within which the starburst is occurring. We find the atomic and molecular gases to trace different kinematical features and believe that the fastest part (>~130kms-1) of the subkpc ring consists overwhelmingly of molecular gas. Beyond the inner kpc, the velocity climbs to settle into a solid body rotation of ~ 150kms-1 at >~10kpc. Most of the starlight emanates from within this radius and so much of the dynamical mass, which remains climbing to the limit of our data (>~50kpc), must be due to the dark matter halo.

  3. Halo phenomenon in finite many-fermion systems: Atom-positron complexes and large-scale study of atomic nuclei

    SciTech Connect

    Rotival, V. [DPTA/Service de Physique Nucleaire, CEA/DAM Ile-de-France, BP12-91680 Bruyeres-le-Chatel (France); National Superconducting Cyclotron Laboratory, 1 Cyclotron Laboratory, East Lansing, Michigan 48824 (United States); Bennaceur, K. [Universite de Lyon, F-69003 Lyon (France); Institut de Physique Nucleaire de Lyon, CNRS/IN2P3, Universite Lyon 1, F-69622 Villeurbanne (France); CEA, Centre de Saclay, IRFU/Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Duguet, T. [National Superconducting Cyclotron Laboratory, 1 Cyclotron Laboratory, East Lansing, Michigan 48824 (United States); CEA, Centre de Saclay, IRFU/Service de Physique Nucleaire, F-91191 Gif-sur-Yvette (France); Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States)

    2009-05-15

    The analysis method proposed in V. Rotival and T. Duguet [Phys. Rev. C 79, 054308 (2009)] is applied to characterize halo properties in finite many-fermion systems. First, the versatility of the method is highlighted by applying it to light- and medium-mass nuclei as well as to atom-positron and ion-positronium complexes. Second, the dependence of nuclear halo properties on the characteristics of the energy-density functional used in self-consistent Hartree-Fock-Bogoliubov calculations is studied. We focus in particular on the influence of (i) the scheme used to regularize/renormalize the ultraviolet divergence of the local pairing functional, (ii) the angular-momentum cutoff in the single-particle basis, as well as (iii) the isoscalar effective mass, (iv) saturation density, and (v) tensor terms characterizing the particle-hole part of the energy functional. It is found that (a) the low-density behavior of the pairing functional and the regularization/renormalization scheme must be chosen coherently and with care to provide meaningful predictions, (b) the impact of pairing correlations on halo properties is significant and is the result of two competing effects, (c) the detailed characteristics of the pairing functional has, however, only little importance, and (d) halo properties depend significantly on any ingredient of the energy-density functional that influences the location of single-particle levels; i.e., the effective mass, the tensor terms, and the saturation density of nuclear matter. The latter dependencies give insights to how experimental data on medium-mass drip-line nuclei can be used in the distant future to constrain some characteristics of the nuclear energy-density functional. Last but not least, large-scale predictions of halos among all spherical even-even nuclei are performed using specific sets of particle-hole and particle-particle energy functionals. It is shown that halos in the ground state of medium-mass nuclei will be found only at the very limit of neutron stability and for a limited number of elements.

  4. Electron transfer and ionic displacements at the origin of the 2D electron gas at the LAO/STO interface: direct measurements with atomic-column spatial resolution.

    PubMed

    Cantoni, Claudia; Gazquez, Jaume; Miletto Granozio, Fabio; Oxley, Mark P; Varela, Maria; Lupini, Andrew R; Pennycook, Stephen J; Aruta, Carmela; di Uccio, Umberto Scotti; Perna, Paolo; Maccariello, Davide

    2012-08-01

    Using state-of-the-art, aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy with atomic-scale spatial resolution, experimental evidence for an intrinsic electronic reconstruction at the LAO/STO interface is shown. Simultaneous measurements of interfacial electron density and system polarization are crucial for establishing the highly debated origin of the 2D electron gas. PMID:22711448

  5. Displaced-T Site Occupancy of Hydrogen in Nb Alloyed with a High Concentration of Mo

    NASA Astrophysics Data System (ADS)

    Yagi, Eiichi; Koike, Shigetoshi; Sugawara, Takamasa; Shishido, Toetsu; Urai, Teruo; Ogiwara, Kiyoshi

    2006-03-01

    The site occupancy of hydrogen in 52 at. % Nb-48 at. % Mo alloys is investigated at room temperature for hydrogen concentrations 0.028 and 0.055 in the hydrogen-metal-atom ratio (CH=[H]/[M]) by the channelling method utilizing a nuclear reaction 1H(11B,?)?? with a 11B beam. A large portion of H atoms are located at sites displaced from tetrahedral (T) sites towards their nearest neighbour octahedral (O) sites by about 0.3 Å (displaced-T sites; d-T), which are similar to the sites observed in V under uniaxial stress and completely different from the sites observed in the Nb alloys containing undersized Mo atoms up to 26 at. %. For CH=0.028 and 0.055, 30-40% and 15-25% of H atoms are located at T sites, respectively.

  6. Large parity violating effects in atomic dysprosium with nearly degenerate Floquet eigenvalues

    E-print Network

    T. Gasenzer; O. Nachtmann

    1999-09-14

    In this article we study effects of parity nonconservation in atomic dysprosium, where one has a pair of nearly degenerate levels of opposite parity. We consider the time evolution of this two-level system within oscillatory electric and magnetic fields. These are chosen to have a periodical structure with the same period, such that a Floquet matrix describes the time evolution of the quantum states. We show that, if the states are unstable, the eigenvalues of the Floquet matrix may have contributions proportional to the square root of the parity violating interaction matrix element $H_w$ while they are almost degenerate in their parity even part. This leads to beat frequencies proportional to $\\sqrt{H_w}$ which are expected to be larger by several orders of magnitude compared to ordinary P-violating contributions which are of order $H_w$. However, for the simple field configurations we considered, it still seems to be difficult to observe these P-violating beat effects, since the states decay too fast. On the other hand, we found that, within only a few Floquet cycles, very large parity violating asymmetries with respect to experimental setups of opposite chirality may be obtained. The electric and magnetic fields as well as the time intervals necessary for this are in an experimentally accessible range. For statistically significant effects beyond one standard deviation a number of about $10^7$ atoms is required. Our ideas may be applied directly to other 2-level atomic systems and different field configurations. We hope that these ideas will stimulate experimental work in this direction.

  7. Nano-scale displacement sensing based on van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Hu, Lin; Zhao, Jin; Yang, Jinlong

    2015-05-01

    We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical displacement. For lateral displacement, the change of dz is induced by atomic layer corrugation. Despite the different stacking configurations of BLBP, we find that the change of the indirect band gap is proportional to dz-2. Furthermore, this dz-2 dependence is found to be applicable to other graphene-like corrugated bi-layer materials such as MoS2. BLBP represents a large family of bi-layer 2D atomic corrugated materials for which the electronic structure is sensitive to the interlayer vertical and lateral displacement, and thus could be used for a nano-scale displacement sensor. This can be done by monitoring the tunable electronic structure using absorption spectroscopy. Because this type of sensor is established on atomic layers coupled through vdW interactions, it provides unique applications in the measurements of nano-scale displacement induced by tiny external forces.We propose that a nano-scale displacement sensor with high resolution in weak-force systems can be realized based on vertically stacked two-dimensional (2D) atomic corrugated layer materials bound through van der Waals (vdW) interactions. Using first-principles calculations, we found that the electronic structures of bi-layer blue phosphorus (BLBP) vary appreciably with lateral and vertical interlayer displacements. The variation of the electronic structure is attributed to the change of the interlayer distance dz for both the lateral and vertical displacement. For lateral displacement, the change of dz is induced by atomic layer corrugation. Despite the different stacking configurations of BLBP, we find that the change of the indirect band gap is proportional to dz-2. Furthermore, this dz-2 dependence is found to be applicable to other graphene-like corrugated bi-layer materials such as MoS2. BLBP represents a large family of bi-layer 2D atomic corrugated materials for which the electronic structure is sensitive to the interlayer vertical and lateral displacement, and thus could be used for a nano-scale displacement sensor. This can be done by monitoring the tunable electronic structure using absorption spectroscopy. Because this type of sensor is established on atomic layers coupled through vdW interactions, it provides unique applications in the measurements of nano-scale displacement induced by tiny external forces. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr00023h

  8. 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 ?m and 40 ?m 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.

  9. Displacements, Strains, and Tilts at Teleseismic Distances

    Microsoft Academic Search

    1965-01-01

    The dislocation theory representation of faulting of Vvedenskaya, Steketee, Chin- nery, and Maruyama is used to compute the residual displacement, strain, and tilt fields at intermediate and large distances from major earthquakes. It is shown that the distant fields are large enough to be detected by modern instruments. The vertical displacement field from the Alaskan earthquake of March 27, 1964,

  10. Displacement cross sections and PKA spectra: tables and applications. [Neutron damage energy cross sections to 20 MeV, primary knockon atom spectra to 15 MeV

    Microsoft Academic Search

    D. G. Doran; N. J. Graves

    1976-01-01

    Damage energy cross sections to 20 MeV are given for aluminum, vanadium, chromium, iron, nickel, copper, zirconium, niobium, molybdenum, tantalum, tungsten, lead, and 18Cr10Ni stainless steel. They are based on ENDF\\/B-IV nuclear data and the Lindhard energy partition model. Primary knockon atom (PKA) spectra are given for aluminum, iron, niobium, tantalum, and lead for neutron energies up to 15 MeV

  11. Halo phenomenon in finite many-fermion systems: Atom-positron complexes and large-scale study of atomic nuclei

    Microsoft Academic Search

    V. Rotival; K. Bennaceur; T. Duguet

    2009-01-01

    The analysis method proposed in V. Rotival and T. Duguet [Phys. Rev. C 79, 054308 (2009)] is applied to characterize halo properties in finite many-fermion systems. First, the versatility of the method is highlighted by applying it to light- and medium-mass nuclei as well as to atom-positron and ion-positronium complexes. Second, the dependence of nuclear halo properties on the characteristics

  12. Critical displacement for unlimited displacement of earthquake-induced landslides

    NASA Astrophysics Data System (ADS)

    Fukuoka, H.; Karnawati, D.; Dok, A.

    2012-04-01

    The 30 September 2009 Padang Earthquake not only affected the buildings and infrastructure of the city, but also induced numerous landslides in the remote hill slopes. (1) A lot of shallow landslides took place along the southern crater rim of the lake Singkarak. Some of them were fluidized and ran as debris flows. (2) In a small town, located south of the lake, several large scale and long run-out landslides took place on hill slopes of pumiceous materials and claimed as many casualties. Those sands were sampled in a landslide deposits and tested by undrained ring shear apparatus by applying cyclic loading with corresponding static normal stress and shear stress. We found that about 5 cm could be the critical shear displacement when the shear resistance get smaller than shear stress due to excess pore pressure generation and thereafter unlimited displacement would appear. The critical displacement may depends on the saturation degree, static stresses acting on the slope, material, density, etc.

  13. Large-scale pseudostate calculations for electron scattering from neon atoms

    NASA Astrophysics Data System (ADS)

    Zatsarinny, Oleg; Bartschat, Klaus

    2012-06-01

    We report large-scale R-matrix (close-coupling) with pseudostates calculations for electron scattering from Ne atoms. The present calculations were performed in the nonrelativistic LS-coupling approximation with a recently developed parallel version of our suite of B-spline R-matrix codes. The principal goal was to generate converged (with the number of states in the close-coupling expansion) results for angle-integrated elastic, ionization, and total cross sections. The cross sections for excitation, which are also required for the latter, are generated in this nonrelativistic model as the sum for all terms. The close-coupling expansion used in this work includes 679 target states, with the lowest-lying 55 states representing the Ne bound spectrum and the remaining 624 states representing the ionization continuum. Our results are in close agreement with available experimental data for the elastic and total cross sections over the wide range of electron energies between 0.1 and 200 eV. With the pseudostate approach, we also obtain accurate cross sections for ionization from both the ground and the metastable states of neon. Our results confirm the very strong influence of coupling to the target continuum on theoretical predictions for excitation cross sections in Ne at intermediate energies, an effect that was previously reported by Ballance and Griffin [J. Phys. BJPAPEH0953-407510.1088/0953-4075/37/14/008 37, 2943 (2004)].

  14. Approximate symmetries in atomic nuclei from a large-scale shell-model perspective

    NASA Astrophysics Data System (ADS)

    Launey, K. D.; Draayer, J. P.; Dytrych, T.; Sun, G.-H.; Dong, S.-H.

    2015-05-01

    In this paper, we review recent developments that aim to achieve further understanding of the structure of atomic nuclei, by capitalizing on exact symmetries as well as approximate symmetries found to dominate low-lying nuclear states. The findings confirm the essential role played by the Sp(3, ?) symplectic symmetry to inform the interaction and the relevant model spaces in nuclear modeling. The significance of the Sp(3, ?) symmetry for a description of a quantum system of strongly interacting particles naturally emerges from the physical relevance of its generators, which directly relate to particle momentum and position coordinates, and represent important observables, such as, the many-particle kinetic energy, the monopole operator, the quadrupole moment and the angular momentum. We show that it is imperative that shell-model spaces be expanded well beyond the current limits to accommodate particle excitations that appear critical to enhanced collectivity in heavier systems and to highly-deformed spatial structures, exemplified by the second 0+ state in 12C (the challenging Hoyle state) and 8Be. While such states are presently inaccessible by large-scale no-core shell models, symmetry-based considerations are found to be essential.

  15. Efficient Geomechanical Simulations of Large-Scale Naturally Fractured Reservoirs Using the Fast Multipole-Displacement Discontinuity Method (FM-DDM)

    E-print Network

    Verde Salas, Alexander José

    2014-04-28

    -7. Transient response of pressure and displacements at the injector and producer wells – Case 2……………………………………… 58 Figure 5-8. Fracture response to Mode II or pore pressure loading. The fracture tends to close under this loading mode – Case 3………… 59... between DDM and FM-DDM for increasing numbers of DOFs – Case 4……………………… 64 Figure 5-14. Comparison of the CPU time between DDM and FM-DDM for increasing numbers of DOFs – Case 4……………………………. 64 Figure 5-15. Locations of the injector and producer...

  16. Particle displacement tracking for PIV

    NASA Technical Reports Server (NTRS)

    Wernet, Mark P.

    1990-01-01

    A new Particle Imaging Velocimetry (PIV) data acquisition and analysis system, which is an order of magnitude faster than any previously proposed system has been constructed and tested. The new Particle Displacement Tracing (PDT) system is an all electronic technique employing a video camera and a large memory buffer frame-grabber board. Using a simple encoding scheme, a time sequence of single exposure images are time coded into a single image and then processed to track particle displacements and determine velocity vectors. Application of the PDT technique to a counter-rotating vortex flow produced over 1100 velocity vectors in 110 seconds when processed on an 80386 PC.

  17. THE DISPLACEMENTS OF ANCHORED DIAPHRAGM WALLS

    Microsoft Academic Search

    ANNA SIEMI?SKA-LEWANDOWSKA

    Due to the influence of the engineering works on buildings in the vicinity of deep excava- tions, two large Warsaw underground stations were constantly monitored. The results of measurements of the displacements of diaphragm walls are presented. Assessment of displacements was carried out on the basis of high-precision land surveying of fixed points positioned on diaphragm walls. The conclu- sions

  18. Single Cs Atoms as Collisional Probes in a large Rb Magneto-Optical Trap

    E-print Network

    Weber, Claudia; Spethmann, Nicolas; Meschede, Dieter; Widera, Artur

    2010-01-01

    We study cold inter-species collisions of Caesium and Rubidium in a strongly imbalanced system with single and few Cs atoms. Observation of the single atom fuorescence dynamics yields insight into light-induced loss mechanisms, while both subsystems can remain in steady-state. This significantly simplifies the analysis of the dynamics, as Cs-Cs collisions are effectively absent and the majority component remains unaffected, allowing us to extract a precise value of the Rb-Cs collision parameter. Extending our results to ground state collisions would allow to use single neutral atoms as coherent probes for larger quantum systems.

  19. Large perpendicular magnetic anisotropy of single Co atom on MgO monolayer: A first-principles study

    NASA Astrophysics Data System (ADS)

    Shao, Bin; Shi, Wu-Jun; Feng, Min; Zuo, Xu

    2015-05-01

    Realizing the magnetic bit with a single atom is the ultimate goal for magnetic storage. Based on density functional theory, the magnetic anisotropy (MA) of single Co atom on MgO monolayer has been investigated. Results show that this two dimensional system possesses a large perpendicular MA, about 5.8 meV per Co atom. Besides, there exists remarkable unquenched orbital moments for different magnetization directions, which can be attributed to the reduction of coordination number in two dimensional system and is responsible for the enhanced MA. The Bloch pseudo-wavefunction and band structure of Co d-orbitals have been calculated to elucidate the origin of the perpendicular MA.

  20. A large atomic chlorine source inferred from mid-continental reactive nitrogen chemistry

    E-print Network

    mercury1 and hydrocarbons such as the greenhouse gas methane2 . Chlorine atoms also influence cycles) represents a terminal NOx sink in the lower troposphere, whereas reaction (1b) recycles NOx through ClNO2

  1. Towards large area and continuous MoS2 atomic layers via vapor-phase growth: thermal vapor sulfurization.

    PubMed

    Liu, Hongfei; Ansah Antwi, K K; Ying, Jifeng; Chua, Soojin; Chi, Dongzhi

    2014-10-10

    We report on the effects of substrate, starting material, and temperature on the growth of MoS(2) atomic layers by thermal vapor sulfurization in a tube-furnace system. With Mo as the starting material, atomic layers of MoS(2) flakes are obtained on sapphire substrates while a bell-shaped MoS(2) layer, sandwiched by amorphous SiO(2), is obtained on native-SiO(2)/Si substrates under the same sulfurization conditions. An anomalous thickness-dependent Raman shift (A(1g)) of the MoS(2) atomic layers is observed in Mo-sulfurizations on sapphire substrates, which can be attributed to the competition between the effects of thickness and the surface/interface. Both effects vary with the sulfurizing temperatures for a certain initial Mo thickness. The anomalous frequency trend of A(1g) is missing when using MoO(3) instead of Mo as the starting material. In this case, the lateral growth of MoS(2) on sapphire is also largely improved. Furthermore, the area density of the resultant MoS(2) atomic layers is significantly increased by increasing the deposition temperature of the starting MoO(3) to 700 °C; the adjacent ultrathin MoS(2) grains coalesce in one or other direction, forming connected chains in wafer scale. The thickness of the so-obtained MoS(2) is generally controlled by the thickness of the starting material; however, the structural and morphological properties of MoS(2) grains, towards large area and continuous atomic layers, are strongly dependent on the temperature of the initial material deposition, and on the temperature of sulfurization, because of the competition between surface mobility and atom evaporation. PMID:25213380

  2. Precision displacement reference system

    DOEpatents

    Bieg, Lothar F. (Albuquerque, NM); Dubois, Robert R. (Albuquerque, NM); Strother, Jerry D. (Edgewood, NM)

    2000-02-22

    A precision displacement reference system is described, which enables real time accountability over the applied displacement feedback system to precision machine tools, positioning mechanisms, motion devices, and related operations. As independent measurements of tool location is taken by a displacement feedback system, a rotating reference disk compares feedback counts with performed motion. These measurements are compared to characterize and analyze real time mechanical and control performance during operation.

  3. Large Ground-State Entropy Changes for Hydrogen Atom Transfer Reactions of Iron Complexes

    PubMed Central

    Mader, Elizabeth A.; Davidson, Ernest R.

    2008-01-01

    Reported herein are the hydrogen atom transfer (HAT) reactions of two closely related dicationic iron tris ?-diimine complexes. FeII(H2bip) (iron(II) tris[2,2?-bi-1,4,5,6-tetra-hydropyrimidine]diperchlorate) and FeII(H2bim) (iron(II) tris[2,2?-bi-2-imidazoline]diperchlorate) both transfer H• to TEMPO (2,2,6,6-tetramethyl-1-piperidinoxyl) to yield the hydroxylamine, TEMPO-H, and the respective deprotonated iron(III) species, FeIII(Hbip) or FeIII(Hbim). The ground-state thermodynamic parameters in MeCN were determined for both systems using both static and kinetic measurements. For FeII(H2bip) + TEMPO: ?G° = ?0.3 ± 0.2 kcal mol?1, ?H° =?9.4 ± 0.6 kcal mol?1, ?S° = ?30 ± 2 cal mol?1 K?1. For FeII(H2bim) + TEMPO: ?G° = 5.0 ± 0.2 kcal mol?1, ?H° = ?4.1 ± 0.9 kcal mol?1, ?S° = ?30 ± 3 cal mol?1 K?1. The large entropy changes for these reactions, |T?S°| = 9 kcal mol?1 at 298 K, are exceptions to the traditional assumption that ?S° ? 0 for simple HAT reactions. Various studies indicate that hydrogen-bonding, solvent effects, ion-pairing, and iron spin-equilibria do not make major contributions to the observed ?S°HAT. Instead, this effect arises primarily from changes in vibrational entropy upon oxidation of the iron center. Measurement of the electron transfer half-reaction entropy, |?S° Fe(H2bim)/ET| = 29 ± 3 cal mol?1 K?1, is consistent with a vibrational origin. This conclusion is supported by UHF/6-31G* calculations on the simplified reaction [FeII(H2N=CHCH=NH2)2(H2bim)]2+•••ONH2 ? [FeII(H2N=CHCH=NH2)2(Hbim)]2+•••HONH2. The discovery that ?S°HAT can deviate significantly from zero has important implications on the study of HAT and proton-coupled electron transfer (PCET) reactions. For instance, these results indicate that free energies, rather than enthalpies, should be used to estimate the driving force for HAT when transition metal centers are involved. PMID:17402735

  4. Tsunami generation by horizontal displacement of ocean bottom

    Microsoft Academic Search

    Yuichiro Tanioka; Kenji Satake

    1996-01-01

    Tsunami generation by an earthquake is generally modeled by water surface displacement identical to the vertical deformation of ocean bottom due to faulting. The effect of horizontal deformation is usually neglected. However, when the tsunami source is on a steep slope and the horizontal displacement is large relative to the vertical displacement, the effect becomes significant. We show this for

  5. Implications of Research on Displaced Workers. ERIC Digest No. 80.

    ERIC Educational Resources Information Center

    Naylor, Michele

    Worker displacement is more closely related to structural features associated with firms than to the characteristics of the individuals who lost their jobs. Despite economic growth, large numbers of displaced workers continue to experience difficulty in making labor market adjustments. Programs to retrain and reemploy displaced workers exist at…

  6. Low photon scattering rates and large optical depths of atoms in donut modes of hollow core optical fibers

    NASA Astrophysics Data System (ADS)

    Pechkis, Joseph A.; Fatemi, Fredrik K.

    2012-06-01

    We have guided cold rubidium atoms in blue-detuned hollow optical modes of a hollow fiber. These higher order modes allow large optical depth, low scattering rates, and efficient use of guide laser power. Atoms are transported through a 3-cm-long hollow fiber with a 100 micron diameter using the first three optical modes of the fiber. We compare guiding properties in the red-detuned, fundamental HE11 mode with the blue-detuned TE01 (first order) and HE12 (second order) modes. Using guide laser powers below 50 mW and detunings below 1.5 nm, we have directly measured recoil scattering rates in the three different guides and found that atoms in the HE12 mode typically have a 10x lower recoil scattering rate compared to the red-detuned HE11 mode for equal guide peak intensity. Furthermore, we have observed optical depths of ˜20 for the blue-detuned guides with recoil scattering rates below 10 Hz. We will discuss our ongoing experiments using the atoms in these guides. This work supported by the Office of Naval Research and the Defense Advanced Research Projects Agency.

  7. GRASP92: a package for large-scale relativistic atomic structure calculations

    NASA Astrophysics Data System (ADS)

    Parpia, F. A.; Froese Fischer, C.; Grant, I. P.

    2006-12-01

    Program summaryTitle of program: GRASP92 Catalogue identifier: ADCU_v1_1 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADCU_v1_1 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: no Programming language used: Fortran Computer: IBM POWERstation 320H Operating system: IBM AIX 3.2.5+ RAM: 64M words No. of lines in distributed program, including test data, etc.: 65 224 No of bytes in distributed program, including test data, etc.: 409 198 Distribution format: tar.gz Catalogue identifier of previous version: ADCU_v1_0 Journal reference of previous version: Comput. Phys. Comm. 94 (1996) 249 Does the new version supersede the previous version?: Yes Nature of problem: Prediction of atomic spectra—atomic energy levels, oscillator strengths, and radiative decay rates—using a 'fully relativistic' approach. Solution method: Atomic orbitals are assumed to be four-component spinor eigenstates of the angular momentum operator, j=l+s, and the parity operator ?=??. Configuration state functions (CSFs) are linear combinations of Slater determinants of atomic orbitals, and are simultaneous eigenfunctions of the atomic electronic angular momentum operator, J, and the atomic parity operator, P. Lists of CSFs are either explicitly prescribed by the user or generated from a set of reference CSFs, a set of subshells, and rules for deriving other CSFs from these. Approximate atomic state functions (ASFs) are linear combinations of CSFs. A variational functional may be constructed by combining expressions for the energies of one or more ASFs. Average level (AL) functionals are weighted sums of energies of all possible ASFs that may be constructed from a set of CSFs; the number of ASFs is then the same as the number, n, of CSFs. Optimal level (OL) functionals are weighted sums of energies of some subset of ASFs; the GRASP92 package is optimized for this latter class of functionals. The composition of an ASF in terms of CSFs sharing the same quantum numbers is determined using the configuration-interaction (CI) procedure that results upon varying the expansion coefficients to determine the extremum of a variational functional. Radial functions may be determined by numerically solving the multiconfiguration Dirac-Fock (MCDF) equations that result upon varying the orbital radial functions or some subset thereof so as to obtain an extremum of the variational functional. Radial wavefunctions may also be determined using a screened hydrogenic or Thomas-Fermi model, although these schemes generally provide initial estimates for MCDF self-consistent-field (SCF) calculations. Transition properties for pairs of ASFs are computed from matrix elements of multipole operators of the electromagnetic field. All matrix elements of CSFs are evaluated using the Racah algebra. Reasons for the new version: During recent studies using the general relativistic atomic structure package (GRASP92), several errors were found, some of which might have been present already in the earlier GRASP92 version (program ABJN_v1_0, Comput. Phys. Comm. 55 (1989) 425). These errors were reported and discussed by Froese Fischer, Gaigalas, and Ralchenko in a separate publication [C. Froese Fischer, G. Gaigalas, Y. Ralchenko, Comput. Phys. Comm. 175 (2006) 738-744. [7

  8. Internal Displacement Monitoring Centre

    NSDL National Science Digital Library

    The Internal Displacement Monitoring Centre (IDMC) was established twelve years ago in the hope that they would "raise awareness of the plight of internally displaced people (IDP), point to gaps in national and international responses and promote solutions reflecting international standards and best practices." The Centre also keeps a database of 50 countries in which people have been displaced within their own country due to conflicts or human rights violations. To get a sense of where displaced persons are and how many countries have IDPs, visitors can click on the small world map on the far right hand side of the homepage. Scrolling over the map will reveal the number of displaced people by continent. Visitors interested in learning about an individual country can click on the continent, then click on one of the countries for an "Internal Displacement Profile", "Country Statistics", and an "Overview". The Resources tab, at the top of any page, includes "IDMC Publications", "Picture Galleries" of internally displaced people in India, Cyprus, and the West Bank, to name a few, and "IDP Maps" which has dozens of maps of from 2001 to 2009.

  9. Calculating hyperfine couplings in large ionic crystals containing hundreds of QM atoms: subsystem DFT is the key.

    PubMed

    Kevorkyants, Ruslan; Wang, Xiqiao; Close, David M; Pavanello, Michele

    2013-11-14

    We present an application of the linear scaling frozen density embedding (FDE) formulation of subsystem DFT to the calculation of isotropic hyperfine coupling constants (hfcc's) of atoms belonging to a guanine radical cation embedded in a guanine hydrochloride monohydrate crystal. The model systems range from an isolated guanine to a 15,000 atom QM/MM cluster where the QM region is comprised of 36 protonated guanine cations, 36 chlorine anions, and 42 water molecules. Our calculations show that the embedding effects of the surrounding crystal cannot be reproduced by small model systems nor by a pure QM/MM procedure. Instead, a large QM region is needed to fully capture the complicated nature of the embedding effects in this system. The unprecedented system size for a relativistic all-electron isotropic hfcc calculation can be approached in this work because the local nature of the electronic structure of the organic crystals considered is fully captured by the FDE approach. PMID:24131238

  10. LargeN expansions in quantum mechanics, atomic physics and some O(N) invariant systems

    Microsoft Academic Search

    Ashok Chatterjee

    1990-01-01

    Some selected topics on the subject of large-N expansions are reviewed here. A brief discussion of large-N critical phenomena is also presented. Generalizing the Schrödinger equation to N-dimensional space, the idea of the large-N limit is introduced in the context of quantum mechanic and the standard methods of 1\\/N expansion such as perturbed oscillator methods and Riccati equation methods are

  11. Atomistic Simulation of Displacement Cascades in Zircon

    SciTech Connect

    Devanathan, Ram; Weber, William J.; Corrales, Louis R.; BP McGrail and GA Cragnolino

    2002-05-06

    Low energy displacement cascades in zircon (ZrSiO4) initiated by a Zr primary knock-on atom have been investigated by molecular dynamics simulations using a Coulombic model for long-range interactions, Buckingham potential for short-range interactions and Ziegler-Biersack potentials for close pair interactions. Displacements were found to occur mainly in the O sublattice, and O replacements by a ring mechanism were predominant. Clusters containing Si interstitials bridged by O interstitials, vacancy clusters and anti-site defects were found to occur. This Si-O-Si bridging is considerable in quenched liquid ZrSiO4.

  12. Atomic oxidation of large area epitaxial graphene on 4H-SiC(0001)

    SciTech Connect

    Velez-Fort, E. [Laboratoire de Photonique et de Nanostructures (CNRS-LPN), Route de Nozay, 91460 Marcoussis (France); Institut de Minéralogie et de Physique des Milieux Condensés, CNRS–UMR7590, Sorbonne Universités-Pierre et Marie Curie, 4 Pl. Jussieu, 75005 Paris (France); Ouerghi, A. [Laboratoire de Photonique et de Nanostructures (CNRS-LPN), Route de Nozay, 91460 Marcoussis (France); Silly, M. G.; Sirtti, F. [Synchrotron-SOLEIL, Saint-Aubin, BP48, F91192 Gif sur Yvette Cedex (France); Eddrief, M.; Marangolo, M. [CNRS, UMR 7588, Institut des NanoSciences de Paris (INSP), F-75005 Paris (France); Sorbonne Universités, UPMC Univ. Paris 06, UMR 7588, INSP, F-75005 Paris (France); Shukla, A. [Institut de Minéralogie et de Physique des Milieux Condensés, CNRS–UMR7590, Sorbonne Universités-Pierre et Marie Curie, 4 Pl. Jussieu, 75005 Paris (France)

    2014-03-03

    Structural and electronic properties of epitaxial graphene on 4H-SiC were studied before and after an atomic oxidation process. X-ray photoemission spectroscopy indicates that oxygen penetrates into the substrate and decouples a part of the interface layer. Raman spectroscopy demonstrates the increase of defects due to the presence of oxygen. Interestingly, we observed on the near edge x-ray absorption fine structure spectra a splitting of the ?* peak into two distinct resonances centered at 284.7 and 285.2?eV. This double structure smears out after the oxidation process and permits to probe the interface architecture between graphene and the substrate.

  13. Rydberg Atom Formation in Ultracold Plasmas: Small Energy Transfer with Large Consequences

    SciTech Connect

    Pohl, T.; Sadeghpour, H. R. [ITAMP, Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, Massachusetts 02138 (United States); Vrinceanu, D. [Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2008-06-06

    We present extensive Monte Carlo calculations of electron-impact-induced transitions between highly excited Rydberg states and provide accurate rate coefficients. For moderate energy changes, our calculations confirm the widely applied expressions in P. Mansbach and J. Keck [Phys. Rev. 181, 275 (1969)] but reveal strong deviations at small energy transfer. Simulations of ultracold plasmas demonstrate that these corrections significantly impact the short-time dynamics of three-body Rydberg atom formation. The improved rate coefficients yield quantitative agreement with recent ultracold plasma experiments.

  14. An atomic magnetometer with autonomous frequency stabilization and large dynamic range

    NASA Astrophysics Data System (ADS)

    Pradhan, S.; Mishra, S.; Behera, R.; Poornima, Dasgupta, K.

    2015-06-01

    The operation of a highly sensitive atomic magnetometer using elliptically polarized resonant light is demonstrated. It is based on measurement of zero magnetic field resonance in degenerate two level systems using polarimetric detection. The transmitted light through the polarimeter is used for laser frequency stabilization, whereas reflected light is used for magnetic field measurement. Thus, the experimental geometry allows autonomous frequency stabilization of the laser frequency leading to compact operation of the overall device and has a preliminary sensitivity of <10 pT/Hz1/2 @ 1 Hz. Additionally, the dynamic range of the device is improved by feedback controlling the bias magnetic field without compromising on its sensitivity.

  15. Large-area Sagnac atom interferometer with robust phase read out

    NASA Astrophysics Data System (ADS)

    Tackmann, Gunnar; Berg, Peter; Abend, Sven; Schubert, Christian; Ertmer, Wolfgang; Rasel, Ernst Maria

    2014-12-01

    We report on recent progress on our matter-wave Sagnac interferometer capable of resolving ultra-slow rotations below the ?rads-1 level with a 1-s measurement time and a repetition rate of 2 Hz. Two Raman interferometers are employed that are susceptible to rotation and acceleration. We demonstrate two read-out schemes exploiting the strict phase correlation of the dual interferometer, the first one locking the interferometer to the mid-fringe position, and the second relying on phase modulation combined with ellipse fitting. In both, the sensitivity to gravity acceleration is employed for controlling the differential interferometer phase without influencing the rotation signal. Furthermore, we discuss errors in the rotation signal arising from atom source instabilities combined with a residual misalignment of the three pulsed light gratings used for atomic diffraction. Monitoring the source position fluctuations allows us to suppress this spurious signal. We achieve stable operation with a sensitivity of 850 nrads-1Hz - 1 / 2 for a 1-s measurement time, and 20 nrads-1 after 4000 s of averaging. xml:lang="fr"

  16. Linking Species Traits to the Abiotic Template of Flowing Waters: Contrasting Eco physiologies Underlie Displacement of Zebra Mussels by Quagga Mussels in a Large River-Estuary

    NASA Astrophysics Data System (ADS)

    Casper, A. F.

    2005-05-01

    The St. Lawrence River-Estuary was the gateway of entry for dreissenids to North America and holds some of the oldest populations. The St. Lawrence also has four distinct physical-chemical water masses (a regional scale abiotic template) that both species inhabit. Despite their ecological similarities, quagga mussels are supplanting zebra mussels in much of their shared range. In order to try to better understand the changing distributions of these two species we compared glycogen, shell mass and tissue biomass in each of the water masses. This comparative physiological combined with experimental approaches (estuarine salinity experiments and reciprocal transplants) showed that while quagga mussels should dominate in most habitats, that abiotic/bioenergetic constraints in two regions (the Ottawa River plume and the freshwater-marine transition zone) might prevent them from dominating these locations. These findings are an example of how the interaction of landscape scale abiotic heterogeneity and a species-specific physiology can have strong impacts of distribution of biota large rivers.

  17. Polymers: Molecular Structure [A polymer is a very large molecule comprising hundreds or thousands of atoms,

    E-print Network

    Hall, Christopher

    1 Polymers: Molecular Structure [A polymer is a very large molecule comprising hundreds into chain or network structures|The concept of the polymer is one of the great ideas of twentieth century chemistry. It emerged in the 1920s amid prolonged controversy and its acceptance is closely associated

  18. Synthesis of Large and Few Atomic Layers of Hexagonal Boron Nitride on Melted Copper

    PubMed Central

    Khan, Majharul Haque; Huang, Zhenguo; Xiao, Feng; Casillas, Gilberto; Chen, Zhixin; Molino, Paul J.; Liu, Hua Kun

    2015-01-01

    Hexagonal boron nitride nanosheets (h-BNNS) have been proposed as an ideal substrate for graphene-based electronic devices, but the synthesis of large and homogeneous h-BNNS is still challenging. In this contribution, we report a facile synthesis of few-layer h-BNNS on melted copper via an atmospheric pressure chemical vapor deposition process. Comparative studies confirm the advantage of using melted copper over solid copper as a catalyst substrate. The former leads to the formation of single crystalline h-BNNS that is several microns in size and mostly in mono- and bi-layer forms, in contrast to the polycrystalline and mixed multiple layers (1–10) yielded by the latter. This difference is likely to be due to the significantly reduced and uniformly distributed nucleation sites on the smooth melted surface, in contrast to the large amounts of unevenly distributed nucleation sites that are associated with grain boundaries and other defects on the solid surface. This synthesis is expected to contribute to the development of large-scale manufacturing of h-BNNS/graphene-based electronics. PMID:25582557

  19. Multi-actuation and PI control: a simple recipe for high-speed and large-range atomic force microscopy.

    PubMed

    Soltani Bozchalooi, I; Youcef-Toumi, K

    2014-11-01

    High speed atomic force microscopy enables observation of dynamic nano-scale processes. However, maintaining a minimal interaction force between the sample and the probe is challenging at high speed specially when using conventional piezo-tubes. While rigid AFM scanners are operational at high speeds with the drawback of reduced tracking range, multi-actuation schemes have shown potential for high-speed and large-range imaging. Here we present a method to seamlessly incorporate additional actuators into conventional AFMs. The equivalent behavior of the resulting multi-actuated setup resembles that of a single high-speed and large-range actuator with maximally flat frequency response. To achieve this, the dynamics of the individual actuators and their couplings are treated through a simple control scheme. Upon the implementation of the proposed technique, commonly used PI controllers are able to meet the requirements of high-speed imaging. This forms an ideal platform for retroactive enhancement of existing AFMs with minimal cost and without compromise on the tracking range. A conventional AFM with tube scanner is retroactively enhanced through the proposed method and shows an order of magnitude improvement in closed loop bandwidth performance while maintaining large range. The effectiveness of the method is demonstrated on various types of samples imaged in contact and tapping modes, in air and in liquid. PMID:25164496

  20. Large displacement fast conducting polymer actuators

    E-print Network

    Chen, Angela Y. (Angela Ying-Ju), 1982-

    2006-01-01

    Conducting polymers are a promising class of electroactive materials that undergo volumetric changes under applied potentials, which make them particularly useful for many actuation applications. Polypyrrole , is one of ...

  1. Sensitivity function analysis of gravitational wave detection with single-laser and large-momentum-transfer atomic sensors

    NASA Astrophysics Data System (ADS)

    Tang, Biao; Zhang, Bao-Cheng; Zhou, Lin; Wang, Jin; Zhan, Ming-Sheng

    2015-03-01

    Recently, a configuration using atomic interferometers (AIs) had been suggested for the detection of gravitational waves. A new AI with some additional laser pulses for implementing large momentum transfer was also put forward, in order to reduce the effect of shot noise and laser frequency noise. We use a sensitivity function to analyze all possible configurations of the new AI and to distinguish how many momenta are transferred in a specific configuration. By analyzing the new configuration, we further explore a detection scheme for gravitational waves, in particular, that ameliorates laser frequency noise. We find that the amelioration occurs in such a scheme, but novelly, in some cases, the frequency noise can be canceled completely by using a proper data processing method. Supported by the National Natural Science Foundation of China.

  2. Effect of energy relaxation of H{sup 0} atoms at the wall on the production profile of H{sup -} ions in large negative ion sources

    SciTech Connect

    Takado, N.; Matsushita, D.; Fujino, I.; Hatayama, A.; Tobari, H.; Inoue, T. [Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522 (Japan); Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 311-0193 (Japan)

    2008-02-15

    Production and transport processes of the H{sup 0} atoms are numerically simulated using a three-dimensional Monte Carlo transport code. The code is applied to the large JAEA 10 ampere negative ion source under a Cs-seeded condition to obtain a spatial distribution of surface-produced H{sup -} ions. In this analysis, we focus on the effect of the energy relaxation of the H{sup 0} atoms at the wall on the H{sup -} ion production from the H{sup 0} atoms. The result indicates that, by considering the energy relaxation of the H{sup 0} atoms at the wall, the production profile of the surface-produced H{sup -} ion is well reflected in the production profile of the H{sup 0} atom production.

  3. Zircon U-Pb ages and Hf isotopic compositions of alkaline silicic magmatic rocks in the Phan Si Pan-Tu Le region, northern Vietnam: Identification of a displaced western extension of the Emeishan Large Igneous Province

    NASA Astrophysics Data System (ADS)

    Usuki, Tadashi; Lan, Ching-Ying; Tran, Trong Hoa; Pham, Thi Dung; Wang, Kuo-Lung; Shellnutt, Gregory J.; Chung, Sun-Lin

    2015-01-01

    In-situ zircon U-Pb and Hf isotope analyses were carried out for alkaline silicic magmatic rocks from the Phan Si Pan-Tu Le region in northern Vietnam to constrain their possible sources and to determine their petrogenetic relationship with the Emeishan Large Igneous Province (ELIP), SW China. Nine granites and nine rhyolites yield zircon 206Pb/238U ages from 262 Ma to 249 Ma, coinciding with the timing of silicic magmatism in the Panxi area of the ELIP. The zircon ?Hf(t) values (+14 to +3) of these granites and rhyolites suggest a moderately depleted mantle source and overlap with those of peralkaline and metaluminous granites in the Panxi area [i.e. ?Hf(t) = +14 to +4]. The zircon Hf isotope ratios show that the zircons probably record the original source characteristics whereas whole-rock Nd isotope data indicate an evidence for crustal contamination that may have occurred at lower temperatures during magma emplacement. The synchroneity, coupled with petrological and geochemical similarities, indicate that silicic rocks from the Phan Si Pan-Tu Le region are cogenetic with the Panxi silicic plutonic rocks and that they are likely derived by similar petrogenetic processes (i.e. fractionation of mafic magmas or partial melting of mafic rocks). Therefore, we propose that the Phan Si Pan-Tu Le region represents a displaced portion of the ELIP inner zone.

  4. Displacement and Velocity Ratios

    NSDL National Science Digital Library

    Bourassa, James

    This interactive presentation, created by James Bourassa and John Rosz for the Electromechanical Digital Library, discusses displacement and velocity ratios. Bourassa and Rosz begin by providing detailed definitions of both topics and then provide mathematical examples of each. Once this basic explanation is complete, the authors allow students to practice these theories in a set of self-correcting quiz questions. Bourassa and Rosz explain each using helpful interactive flash animations. These are not only useful in explanation, but they allow the student to more fully engage with the topic. Overall, this is a nice introduction to the physical and mathematical concepts of displacement and velocity ratios. This could be a valuable learning resource in everything from a physics to a technical education classroom.

  5. Above Water: Buoyancy & Displacement

    NSDL National Science Digital Library

    New Jersey

    2006-01-01

    In an investigation called "Shape It!" learners craft tiny boats out of clay, set them afloat on water and then add weight loads to them, in order to explore: how objects stay afloat in water; what the relationship is among surface tension, buoyancy, density and displacement; and how shape, size, and type of material affect an object's ability to remain buoyant. The introductory text discusses how heavy steel ships can float on bodies of water like rivers, bays and oceans.

  6. Displacement Based Multilevel Structural Optimization

    NASA Technical Reports Server (NTRS)

    Sobieszezanski-Sobieski, J.; Striz, A. G.

    1996-01-01

    In the complex environment of true multidisciplinary design optimization (MDO), efficiency is one of the most desirable attributes of any approach. In the present research, a new and highly efficient methodology for the MDO subset of structural optimization is proposed and detailed, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures is performed. In the system level optimization, the design variables are the coefficients of assumed polynomially based global displacement functions, and the load unbalance resulting from the solution of the global stiffness equations is minimized. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. The approach is expected to prove very efficient since the design task is broken down into a large number of small and efficient subtasks, each with a small number of variables, which are amenable to parallel computing.

  7. Atomically Flat Silicon Surface and Silicon\\/Insulator Interface Formation Technologies for (100) Surface Orientation Large-Diameter Wafers Introducing High Performance and Low-Noise Metal–Insulator–Silicon FETs

    Microsoft Academic Search

    Rihito Kuroda; Tomoyuki Suwa; Akinobu Teramoto; Rui Hasebe; Shigetoshi Sugawa; Tadahiro Ohmi

    2009-01-01

    Technology to atomically flatten the silicon surface on (100) orientation large-diameter wafer and the formation technology of an atomically flat insulator film\\/silicon interface are developed in this paper. Atomically flat silicon surfaces composed of atomic terraces and steps are obtained on (100) orientation 200-mm-diameter wafers by annealing in pure argon ambience at 1200degC for 30 min. Atomically flat surfaces with

  8. The role of energetic displacement cascades in ion beam modifications of materials

    SciTech Connect

    Averback, R.S.; Kim, S.J.; Diaz de la Rubia, T.

    1986-12-01

    The roles of energetic displacement cascades are ubiquitous in the fields of radiation damage and ion beam modifications of materials. These roles can be described on two time scales. For the first, which lasts approx. =10/sup -11/ s, small cascade volumes are characterized by large supersaturations of point defects and energy densities in excess of some tenths of eV's per atom. During this period, the system can be driven far from equilibrium with significant rearrangement of target atoms and the production of Frenkel pairs. Studies of ion beam mixing in conjunction with molecular dynamics computer simulations, have contributed largely toward understanding these dynamic cascade processes. At later times, the microstructure of the material evolves as cascades begin to overlap, or at elevated temperatures, point defects migrate away from their nascent cascades. It is shown how the primary state of damage in cascades influences this microstructural development. Examples involving radiation enhanced diffusion and ion-induced amorphization are discussed. 40 refs.

  9. Wage Loss Following Displacement: The Role of Union Coverage.

    ERIC Educational Resources Information Center

    Kuhn, Peter; Sweetman, Arthur

    1998-01-01

    Data from two Canadian surveys showed that only 32% of dislocated workers had unionized jobs before displacement; their wage loss represented about 80% of wages lost by all displaced workers surveyed. Losing union status was associated with large wage losses regardless of whether they switched industries. (SK)

  10. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor)

    1991-01-01

    Polyimidazoles (Pl) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl)imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethylacetamide, sulfolane, N-methylpyrroldinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperature under nitrogen. The di(hydroxyphenyl)imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl)imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxyphenyl)imidazole monomer. This synthetic route has provided high molecular weight Pl of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  11. Polyimidazoles via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (inventor); Hergenrother, Paul M. (inventor)

    1992-01-01

    Polyimidazoles (PI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) imidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The reactions are carried out in polar aprotic solvents such as N,N-dimethyl acetamide, sulfolane, N-methylpyrrolidinone, dimethylsulfoxide, or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) imidazole monomers are prepared by reacting an aromatic aldehyde with a dimethoxybenzil or by reacting an aromatic dialdehyde with a methoxybenzil in the presence of ammonium acetate. The di(methoxyphenyl) imidazole is subsequently treated with aqueous hydrobromic acid to give the di(hydroxphenyl) imidazole monomer. This synthetic route has provided high molecular weight PI of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the availability of a large variety of activated aromatic dihalides and dinitro compounds.

  12. Adapting to variable prismatic displacement

    NASA Technical Reports Server (NTRS)

    Welch, Robert B.; Cohen, Malcolm M.

    1989-01-01

    In each of two studies, subjects were exposed to a continuously changing prismatic displacement with a mean value of 19 prism diopters (variable displacement) and to a fixed 19-diopter displacement (fixed displacement). In Experiment 1, significant adaptation (post-pre shifts in hand-eye coordination) was found for fixed, but not for variable, displacement. Experiment 2 demonstrated that adaptation was obtained for variable displacement, but it was very fragile and is lost if the measures of adaptation are preceded by even a very brief exposure of the hand to normal or near-normal vision. Contrary to the results of some previous studies, an increase in within-S dispersion was not found of target pointing responses as a result of exposure to variable displacement.

  13. Large shape-persistent metal-invertible 15-Nsp(2)-donor-atom macrocycles functioning as trinucleating ligands.

    PubMed

    Stadler, Adrian-Mihail; Jiang, Ji-Jun; Wang, Hai-Ping; Bailly, Corinne

    2013-05-01

    Reaction of 4,6-dihydrazinopyrimidines with 2,6-dicarbonylpyridines produces, under metal-free or template conditions, a new class of [3 + 3] macrocycles with 15 Nsp(2) donor atoms. Nine Nsp(2) atoms are on the external circumference of the macrocycle. The macrocycle can bind metal ions and produce trinuclear complexes along with the motion of the nine outer Nsp(2) atoms to inner positions (a motion of inversion of the macrocycle). PMID:23546549

  14. Modeling elastomer displacements for tactile sensing applications

    SciTech Connect

    Novak, J.L.

    1990-02-01

    Many capacitance-based tactile sensors measure the displacements of an elastic substrate at multiple sites. A large number of sensing applications, however, require knowledge of the surface forces. This report considers the problem of reconstructing these surface forces from the measured displacements. Two models for reconstruction are considered. Contacts in which the area is much smaller than the dimensions of the compliant surface are modelled using a linear elastic half-space. Analyses of the deformations using this model confirm a strong coupling between normal and tangential displacements for normal, tangential or arbitrary loads. Using a spatial frequency formulation, the minimum spatial sampling densities for reconstructing displacements (as a prerequisite to reconstructing forces) are shown to be significantly smaller than those required for reconstructing strains. The second model, the bonded spring, is introduced for surface contacts which extend over the entire sensor surface. A nonlinear stress-strain relationship is included since tactile sensors undergo relatively large deformations. An empirical relationship between elastic pad geometry and the effective modulus of elasticity is also presented. 22 refs., 5 figs., 1 tab.

  15. Site Change of Hydrogen in Niobium on Alloying with Oversized Ta Atoms

    NASA Astrophysics Data System (ADS)

    Yagi, Eiichi; Yoshii, Motoyasu; Okada, Yoshinori; Matsuba, Hiroshi; Miyahara, Kazuya; Koike, Shigetoshi; Sugawara, Takamasa; Shishido, Toetsu; Ogiwara, Kiyoshi

    2009-06-01

    In order to clarify a difference in hydrogen interaction with oversized solute atoms and with undersized solute atoms in bcc metals in the low solute concentration region, the site occupancy of hydrogen in Nb alloyed with 5 at. % of oversized Ta atoms has been studied at room temperature for hydrogen concentrations of 0.018 and 0.025 at the hydrogen-to-metal-atom ratio (CH=[H]/[M]) by the channelling method utilizing a nuclear reaction 1H(11B,?)?? with a 11B beam of an energy of 2.03 MeV. Clearly different from the result on hydrogen in Nb alloyed with undersized Mo atoms, in both specimens H atoms are distributed over tetrahedral (T) sites and the displaced-T sites (d-T sites) which are displaced from T sites by about 0.25 Å towards their nearest neighbour octahedral (O) sites. The T site is more favourable for hydrogen occupancy, but the number of available T sites is limited, and excess H atoms occupy the d-T sites. Therefore, in contrast to a strong attractive interaction between hydrogen and undersized Mo atoms (trapping), there exists no such a strong attractive interaction between hydrogen and oversized Ta atoms. It is considered that the trapping of hydrogen by undersized solute atoms is effective to the large enhancement of the terminal solubility of hydrogen (TSH) on alloying with undersized solute atoms, at least, in the low solute concentration region.

  16. Numerical analysis of the production profile of H{sup 0} atoms and subsequent H{sup -} ions in large negative ion sources

    SciTech Connect

    Takado, N.; Hanatani, J.; Hatayama, A. [Keio University, 3-14-1 Hiyoshi, Kouhoku-ku, Yokohama 223-8522 (Japan); Tobari, H.; Inoue, T.; Hanada, M.; Kashiwagi, M.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukouyama, Naka 311-0193 (Japan)

    2008-03-01

    The production and transport processes of H{sup 0} atoms are numerically simulated using a three-dimensional Monte Carlo transport code. The code is applied to the large JAEA 10 ampere negative ion source under the Cs-seeded condition to obtain a spatial distribution of surface-produced H{sup -} ions. In this analysis, the amount of H{sup 0} atoms produced through dissociation processes of H{sub 2} molecules is calculated from the electron temperature and density obtained by Langmuir probe measurements. The high-energy tail of electrons, which greatly affects H{sup 0} atom production, is taken into account by fitting a single-probe characteristic as a two-temperature Maxwellian distribution. In the H{sup 0} atom transport process, the energy relaxation of the H{sup 0} atoms, which affects the surface H{sup -} ion production rate, is taken into account. The result indicates that the surface H{sup -} ion production is enhanced near the high-electron-temperature region where H{sup 0} atom production is localized.

  17. Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor

    PubMed Central

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  18. Displacement parameter inversion for a novel electromagnetic underground displacement sensor.

    PubMed

    Shentu, Nanying; Li, Qing; Li, Xiong; Tong, Renyuan; Shentu, Nankai; Jiang, Guoqing; Qiu, Guohua

    2014-01-01

    Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named "EELA forward modeling-approximate inversion method". Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0-100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications. PMID:24858960

  19. Phase stabilization of laser beams in a cold atom accelerometer

    E-print Network

    Byrne, Nicole (Nicole Malenie)

    2014-01-01

    A cold atom accelerometer measures the displacement of a proof mass of laser cooled atoms with respect to an instrument reference frame. The cold atom interferometer's reference frame is defined by a pair of specially ...

  20. Strategies for displacing oil

    NASA Astrophysics Data System (ADS)

    Rao, Vikram; Gupta, Raghubir

    2015-03-01

    Oil currently holds a monopoly on transportation fuels. Until recently biofuels were seen as the means to break this stranglehold. They will still have a part to play, but the lead role has been handed to natural gas, almost solely due to the increased availability of shale gas. The spread between oil and gas prices, unprecedented in its scale and duration, will cause a secular shift away from oil as a raw material. In the transport fuel sector, natural gas will gain traction first in the displacement of diesel fuel. Substantial innovation is occurring in the methods of producing liquid fuel from shale gas at the well site, in particular in the development of small scale distributed processes. In some cases, the financing of such small-scale plants may require new business models.

  1. DNA nanotechnology. Programming colloidal phase transitions with DNA strand displacement.

    PubMed

    Rogers, W Benjamin; Manoharan, Vinothan N

    2015-02-01

    DNA-grafted nanoparticles have been called "programmable atom-equivalents": Like atoms, they form three-dimensional crystals, but unlike atoms, the particles themselves carry information (the sequences of the grafted strands) that can be used to "program" the equilibrium crystal structures. We show that the programmability of these colloids can be generalized to the full temperature-dependent phase diagram, not just the crystal structures themselves. We add information to the buffer in the form of soluble DNA strands designed to compete with the grafted strands through strand displacement. Using only two displacement reactions, we program phase behavior not found in atomic systems or other DNA-grafted colloids, including arbitrarily wide gas-solid coexistence, reentrant melting, and even reversible transitions between distinct crystal phases. PMID:25657244

  2. The use of galvanic displacement in synthesizing Pt(Cu) catalysts with the core-shell structure

    Microsoft Academic Search

    B. I. Podlovchenko; T. D. Gladysheva; A. Yu. Filatov; L. V. Yashina

    2010-01-01

    The formation of a Pt(Cu) bimetallic catalyst on the carbon support by galvanic displacement of copper electrodeposits with\\u000a platinum (PtCl62? as the displacing agent) is systematically studied. Composition, structure, and electrocatalytic properties of samples corresponding\\u000a to different stages of copper displacement are analyzed. For substantially long displacement times, the formation of stable\\u000a Pt(Cu)st particles with the atomic ratio Pt: Cu

  3. Regenerative rotary displacer Stirling engine

    Microsoft Academic Search

    Naotsugu Isshiki; Luca Raggi; S. Isshiki; K. Hirata; H. Watanabe

    1996-01-01

    A few rotary displacer Stirling engines whose displacers have one gas pocket space at one side, and rotate in a main enclosed cylinder, which is heated from one side and cooled from the opposite side without any regenerator have been tried and studied for a considerable time by the authors. They then tried to improve this engine by equipping them

  4. Displacement based multilevel structural optimization

    NASA Technical Reports Server (NTRS)

    Striz, Alfred G.

    1995-01-01

    Multidisciplinary design optimization (MDO) is expected to play a major role in the competitive transportation industries of tomorrow, i.e., in the design of aircraft and spacecraft, of high speed trains, boats, and automobiles. All of these vehicles require maximum performance at minimum weight to keep fuel consumption low and conserve resources. Here, MDO can deliver mathematically based design tools to create systems with optimum performance subject to the constraints of disciplines such as structures, aerodynamics, controls, etc. Although some applications of MDO are beginning to surface, the key to a widespread use of this technology lies in the improvement of its efficiency. This aspect is investigated here for the MDO subset of structural optimization, i.e., for the weight minimization of a given structure under size, strength, and displacement constraints. Specifically, finite element based multilevel optimization of structures (here, statically indeterminate trusses and beams for proof of concept) is performed. In the system level optimization, the design variables are the coefficients of assumed displacement functions, and the load unbalance resulting from the solution of the stiffness equations is minimized. Constraints are placed on the deflection amplitudes and the weight of the structure. In the subsystems level optimizations, the weight of each element is minimized under the action of stress constraints, with the cross sectional dimensions as design variables. This approach is expected to prove very efficient, especially for complex structures, since the design task is broken down into a large number of small and efficiently handled subtasks, each with only a small number of variables. This partitioning will also allow for the use of parallel computing, first, by sending the system and subsystems level computations to two different processors, ultimately, by performing all subsystems level optimizations in a massively parallel manner on separate processors. It is expected that the subsystems level optimizations can be further improved through the use of controlled growth, a method which reduces an optimization to a more efficient analysis with only a slight degradation in accuracy. The efficiency of all proposed techniques is being evaluated relative to the performance of the standard single level optimization approach where the complete structure is weight minimized under the action of all given constraints by one processor and to the performance of simultaneous analysis and design which combines analysis and optimization into a single step. It is expected that the present approach can be expanded to include additional structural constraints (buckling, free and forced vibration, etc.) or other disciplines (passive and active controls, aerodynamics, etc.) for true MDO.

  5. Large-scale synthesis of metastable TiO2(B) nanosheets with atomic thickness and their photocatalytic properties.

    PubMed

    Xiang, Guolei; Li, Tianyang; Zhuang, Jing; Wang, Xun

    2010-09-28

    A one-pot method was developed to prepare atomic thick nanosheets of metastable TiO(2)(B), which has a unique open structure owing to the coupling of intrinsic channels and the preferentially exposed (010) facets. They display high activity of doping due to the rapid incorporation and diffusion along these open channels. PMID:20730205

  6. Visualization of a Large Set of Hydrogen Atomic Orbital Contours Using New and Expanded Sets of Parametric Equations

    ERIC Educational Resources Information Center

    Rhile, Ian J.

    2014-01-01

    Atomic orbitals are a theme throughout the undergraduate chemistry curriculum, and visualizing them has been a theme in this journal. Contour plots as isosurfaces or contour lines in a plane are the most familiar representations of the hydrogen wave functions. In these representations, a surface of a fixed value of the wave function ? is plotted…

  7. Evidence for a large enrichment of interstitial oxygen atoms in the nanometer-thick metal layer at the NbO/Nb (110) interface

    NASA Astrophysics Data System (ADS)

    Arfaoui, I.; Guillot, C.; Cousty, J.; Antoine, C.

    2002-06-01

    The oxide/metal interface induced by surface segregation of oxygen during the annealing of a Nb single crystal in UHV has been studied by photoemission spectroscopy with synchrotron radiation. With 260 and 350 eV photons, four well-resolved peaks A, B, C, D are found in spectra within the 200-210 eV range of binding energy. One couple of peaks (A and C) is associated with 3d5/2 and 3d3/2 core levels of Nb atoms in the metal while the other one (B and D), shifted by 1.4 eV when compared to A and C, corresponds to 3d levels of oxidized Nb atoms. The metal peak A at 202.3 eV is formed by three 3d5/2 components: a peak due to a metallic state (202.1 eV) and two components shifted by 0.2 and 0.5 eV, which are attributed to Nb6O and Nb4O compounds due to interstitial atoms of oxygen, respectively. The estimated concentration of the interstitial oxygen atoms in the nanometer-thick metal skin underlying the NbO/Nb interface corresponds to a large enrichment when compared to the one in the Nb bulk.

  8. Measurement of axial injection displacement with trim coil current unbalance.

    PubMed

    Kireeff Covo, Michel

    2014-08-01

    The Dee probe used for measuring internal radial beam intensity shows large losses inside the radius of 20 cm of the 88 in. cyclotron. The current of the top and bottom innermost trim coil 1 is unbalanced to study effects of the axial injection displacement. A beam profile monitor images the ion beam bunches, turn by turn. The experimental bunch center of mass position is compared with calculations of the magnetic mirror effect displacement and shows good agreement. PMID:25173318

  9. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole...Materials (ASTM) E 29-67. (b) For rotary engines, displacement means the maximum...

  10. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole...Materials (ASTM) E 29-67. (b) For rotary engines, displacement means the maximum...

  11. 40 CFR 205.153 - Engine displacement.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and rounded to the nearest whole...Materials (ASTM) E 29-67. (b) For rotary engines, displacement means the maximum...

  12. Displacement sensing system and method

    DOEpatents

    VunKannon, Jr., Robert S

    2006-08-08

    A displacement sensing system and method addresses demanding requirements for high precision sensing of displacement of a shaft, for use typically in a linear electro-dynamic machine, having low failure rates over multi-year unattended operation in hostile environments. Applications include outer space travel by spacecraft having high-temperature, sealed environments without opportunity for servicing over many years of operation. The displacement sensing system uses a three coil sensor configuration, including a reference and sense coils, to provide a pair of ratio-metric signals, which are inputted into a synchronous comparison circuit, which is synchronously processed for a resultant displacement determination. The pair of ratio-metric signals are similarly affected by environmental conditions so that the comparison circuit is able to subtract or nullify environmental conditions that would otherwise cause changes in accuracy to occur.

  13. Protein-water displacement distributions.

    PubMed

    Doster, Wolfgang; Settles, Marcus

    2005-06-01

    The statistical properties of fast protein-water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays two dynamical components, related to librational motions and anomalous diffusion along the protein surface. Rotational transitions of side chains, in particular of methyl groups, persist in the dehydrated and in the solvent-vitrified protein structure. The interaction with water induces further continuous protein motions on a small scale. Water acts as a plasticizer of displacements, which couple to functional processes such as open-closed transitions and ligand exchange. PMID:15893505

  14. Geometric Deformation-Displacement Maps

    Microsoft Academic Search

    Gershon Elber

    2002-01-01

    Texture mapping, bump mapping, and displacement maps are central instruments in computer graphics aiming to achieve photo-realistic renderings. In all these techniques, the mapping is typically one-to-one and a single surface location is assigned a single texture color, normal, or displacement. Other specialized techniques have also been developed for the rendering of supplementary surface details such as fur hair, or

  15. Hybrid functionals for large periodic systems in an all-electron, numeric atom-centered basis framework

    NASA Astrophysics Data System (ADS)

    Levchenko, Sergey V.; Ren, Xinguo; Wieferink, Jürgen; Johanni, Rainer; Rinke, Patrick; Blum, Volker; Scheffler, Matthias

    2015-07-01

    We describe a framework to evaluate the Hartree-Fock exchange operator for periodic electronic-structure calculations based on general, localized atom-centered basis functions. The functionality is demonstrated by hybrid-functional calculations of properties for several semiconductors. In our implementation of the Fock operator, the Coulomb potential is treated either in reciprocal space or in real space, where the sparsity of the density matrix can be exploited for computational efficiency. Computational aspects, such as the rigorous avoidance of on-the-fly disk storage, and a load-balanced parallel implementation, are also discussed. We demonstrate linear scaling of our implementation with system size by calculating the electronic structure of a bulk semiconductor (GaAs) with up to 1,024 atoms per unit cell without compromising the accuracy.

  16. Are large concentration of atomic H storable in tritium-impregnated solid in H2 below 0.10 K

    NASA Technical Reports Server (NTRS)

    Rosen, G.; Webeler, R. W. H.

    1979-01-01

    The storage and release of atomic hydrogen produced by the beta decay of tritium contained in a crystalline solid H2 matrix at concentrations greater than 2% and temperatures below 0.80 K are investigated. The temperature of a sample chamber containing tritium-impregnated H2 and placed in the mixing chamber of a dilution refrigerator was measured as the chamber was heated and cooled in order to determine the rates of energy storage and release. It is found that for samples containing 1.2 wt.% tritium, after storage at 0.054 K for 40 h, an increase in sample temperature to a trigger point of 0.17 K leads to an energy release due to the destabilization of atomic H in H2 as predicted by the phenomenological rate process theory. For a tritium weight fraction of 2.5%, energy releases were triggered at 0.54 and 0.82 K after storage at 0.080 K, indicating the trapping of H atoms at the sites of T2 and HT molecules in the sample. The application of a 15 kG magnetic field is shown to increase the storage capacity of T2 traps while reducing that of HT traps, and to lower the trigger temperatures of both. Results suggest that the direct conversion of nuclear energy to chemical energy may become technically feasible in the future.

  17. Development of a high dynamic range spectroscopic system for observation of neutral hydrogen atom density distribution in Large Helical Device core plasma

    SciTech Connect

    Fujii, K., E-mail: fujii@me.kyoto-u.ac.jp; Atsumi, S.; Watanabe, S.; Shikama, T.; Hasuo, M. [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan)] [Department of Mechanical Engineering and Science, Graduate School of Engineering, Kyoto University, Kyoto 606-8540 (Japan); Goto, M.; Morita, S. [National Institute for Fusion Science, Toki 509-5292 (Japan)] [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-02-15

    We report development of a high dynamic range spectroscopic system comprising a spectrometer with 30% throughput and a camera with a low-noise fast-readout complementary metal-oxide semiconductor sensor. The system achieves a 10{sup 6} dynamic range (?20 bit resolution) and an instrumental function approximated by a Voigt profile with Gauss and Lorentz widths of 31 and 0.31 pm, respectively, for 656 nm light. The application of the system for line profile observations of the Balmer-? emissions from high temperature plasmas generated in the Large Helical Device is also presented. In the observed line profiles, emissions are detected in far wings more than 1.0 nm away from the line center, equivalent to neutral hydrogen atom kinetic energies above 1 keV. We evaluate atom density distributions in the core plasma by analyzing the line profiles.

  18. First-principles studies on vacancy-modified interstitial diffusion mechanism of oxygen in nickel, associated with large-scale atomic simulation techniques

    SciTech Connect

    Fang, H. Z.; Shang, S. L.; Wang, Y.; Liu, Z. K. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Alfonso, D.; Alman, D. E. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); National Energy Technology Laboratory, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Shin, Y. K.; Zou, C. Y.; Duin, A. C. T. van [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Lei, Y. K.; Wang, G. F. [National Energy Technology Laboratory Regional University Alliance, U.S. Department of Energy, Pittsburgh, Pennsylvania 15236 (United States); Department of Mechanical Engineering and Materials Science, University of Pittsburgh, Pennsylvania 15261 (United States)

    2014-01-28

    This paper is concerned with the prediction of oxygen diffusivities in fcc nickel from first-principles calculations and large-scale atomic simulations. Considering only the interstitial octahedral to tetrahedral to octahedral minimum energy pathway for oxygen diffusion in fcc lattice, greatly underestimates the migration barrier and overestimates the diffusivities by several orders of magnitude. The results indicate that vacancies in the Ni-lattice significantly impact the migration barrier of oxygen in nickel. Incorporation of the effect of vacancies results in predicted diffusivities consistent with available experimental data. First-principles calculations show that at high temperatures the vacancy concentration is comparable to the oxygen solubility, and there is a strong binding energy and a redistribution of charge density between the oxygen atom and vacancy. Consequently, there is a strong attraction between the oxygen and vacancy in the Ni lattice, which impacts diffusion.

  19. Molecular Dynamics Simulations of Displacement Cascades in Single and Polycrystalline Zirconia

    SciTech Connect

    Du Jincheng [Department of Materials Science and Engineering, Center for Advanced Scientific Computing and Modeling, University of North Texas (United States)

    2009-03-10

    Displacement cascades in zirconia have been studied using classical molecular dynamics simulations. Polycrystalline zirconia with nano-meter grains were created using Voronoi polyhedra construction and studied in comparison with single crystalline zirconia. The results show that displacement cascades with similar kinetic energy generated larger number of displaced atoms in polycrystalline than in the single crystal structure. The fraction of atoms with coordination number change was also higher in polycrystalline zirconia that was explained to be due to the diffusion of oxygen and relaxation at grain boundaries.

  20. DISPLACEMENT CASCADE SIMULATION IN TUNGSTEN AT 1025 K

    SciTech Connect

    Setyawan, Wahyu; Nandipati, Giridhar; Roche, Kenneth J.; Heinisch, Howard L.; Kurtz, Richard J.; Wirth, Brian D.

    2013-09-30

    Molecular dynamics simulation was employed to investigate the irradiation damage properties of bulk tungsten at 1025 K (0.25 melting temperature). A comprehensive data set of primary cascade damage was generated up to primary knock-on atom (PKA) energies 100 keV. The dependence of the number of surviving Frenkel pairs (NFP) on the PKA energy (E) exhibits three different characteristic domains presumably related to the different cascade morphologies that form. The low-energy regime < 0.2 keV is characterized by a hit-or-miss type of Frenkel pair (FP) production near the displacement threshold energy of 128 eV. The middle regime 0.3 – 30 keV exhibits a sublinear dependence of log(NFP) vs log(E) associated with compact cascade morphology with a slope of 0.73. Above 30 keV, the cascade morphology consists of complex branches or interconnected damage regions. In this extended morphology, large interstitial clusters form from superposition of interstitials from nearby damage regions. Strong clustering above 30 keV results in a superlinear dependence of log(NFP) vs log(E) with a slope of 1.365. At 100 keV, an interstitial cluster of size 92 and a vacancy cluster of size 114 were observed.

  1. Large-Scale Fabrication of Carbon Nanotube Probe Tips For Atomic Force Microscopy Critical Dimension Imaging Applications

    NASA Technical Reports Server (NTRS)

    Ye, Qi Laura; Cassell, Alan M.; Stevens, Ramsey M.; Meyyappan, Meyya; Li, Jun; Han, Jie; Liu, Hongbing; Chao, Gordon

    2004-01-01

    Carbon nanotube (CNT) probe tips for atomic force microscopy (AFM) offer several advantages over Si/Si3N4 probe tips, including improved resolution, shape, and mechanical properties. This viewgraph presentation discusses these advantages, and the drawbacks of existing methods for fabricating CNT probe tips for AFM. The presentation introduces a bottom up wafer scale fabrication method for CNT probe tips which integrates catalyst nanopatterning and nanomaterials synthesis with traditional silicon cantilever microfabrication technology. This method makes mass production of CNT AFM probe tips feasible, and can be applied to the fabrication of other nanodevices with CNT elements.

  2. Displacement rank of the Drazin inverse

    NASA Astrophysics Data System (ADS)

    Diao, Huaian; Wei, Yimin; Qiao, Sanzheng

    2004-05-01

    In this paper, we study the displacement rank of the Drazin inverse. Both Sylvester displacement and the generalized displacement are discussed. We present upper bounds for the ranks of the displacements of the Drazin inverse. The general results are applied to the group inverse of a structured matrix such as close-to-Toeplitz, generalized Cauchy, Toeplitz-plus-Hankel, and Bezoutians.

  3. Dual pressure displacement control system

    SciTech Connect

    Louis, J.E.; Klocke, C.C.

    1988-02-02

    This patent describes a dual pressure servo control system for a variable displacement hydraulic unit having displacement setting means positioned by a hydraulic servo mechanism. The hydraulic unit is provided with main loop lines at least one of which is capable of being subjected to high main loop pressure during operation of the hydraulic unit, a control line including a displacement control valve providing a controlled flow of fluid under pressure to the servo mechanism, and a source of fluid under pressure for the control line comprising a low pressure source connected to the control line through a check valve and high pressure source comprising of a high pressure control line connected to the control line downstream of the check valve. The high pressure control line includes a flow restriction limiting flow to the control line means and generating a significant flow induced pressure drop in the high pressure control line once movement in the servo mechanism is initiated.

  4. Large-scale analysis of high-speed atomic force microscopy data sets using adaptive image processing

    PubMed Central

    Erickson, Blake W; Coquoz, Séverine; Adams, Jonathan D; Burns, Daniel J

    2012-01-01

    Summary Modern high-speed atomic force microscopes generate significant quantities of data in a short amount of time. Each image in the sequence has to be processed quickly and accurately in order to obtain a true representation of the sample and its changes over time. This paper presents an automated, adaptive algorithm for the required processing of AFM images. The algorithm adaptively corrects for both common one-dimensional distortions as well as the most common two-dimensional distortions. This method uses an iterative thresholded processing algorithm for rapid and accurate separation of background and surface topography. This separation prevents artificial bias from topographic features and ensures the best possible coherence between the different images in a sequence. This method is equally applicable to all channels of AFM data, and can process images in seconds. PMID:23213638

  5. Rotor component displacement measurement system

    DOEpatents

    Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

    2003-05-27

    A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

  6. Accurate Measurement of Electron Beam Induced Displacement Cross Sections for Single-Layer Graphene

    E-print Network

    Krasheninnikov, Arkady V.

    the atomic displacement (``knock-on'') cross section by counting the lost atoms as a function of the electron resolution [2,3] inevitably entail increased doses per area that need to be applied to a sample. The need an image has been acquired. In spite of a wide range of previous studies concerning irradiation damage

  7. Assessing building displacement with GPS

    Microsoft Academic Search

    Andrés Seco; Fermín Tirapu; Francisco Ramírez; Beñat García; Jesús Cabrejas

    2007-01-01

    In the frame of its researches concerning GPS positioning the Universidad Pública de Navarra has carried out in 2003 a study to know the possibilities of this positioning technique for monitoring building's displacements. A 30m concrete building was monitored for several months by observations from a geodetic micronetwork placed around.During the observation period the computed variations in position have standard

  8. DISPLACEMENT BASED SEISMIC DESIGN METHODS.

    SciTech Connect

    HOFMAYER,C.MILLER,C.WANG,Y.COSTELLO,J.

    2003-07-15

    A research effort was undertaken to determine the need for any changes to USNRC's seismic regulatory practice to reflect the move, in the earthquake engineering community, toward using expected displacement rather than force (or stress) as the basis for assessing design adequacy. The research explored the extent to which displacement based seismic design methods, such as given in FEMA 273, could be useful for reviewing nuclear power stations. Two structures common to nuclear power plants were chosen to compare the results of the analysis models used. The first structure is a four-story frame structure with shear walls providing the primary lateral load system, referred herein as the shear wall model. The second structure is the turbine building of the Diablo Canyon nuclear power plant. The models were analyzed using both displacement based (pushover) analysis and nonlinear dynamic analysis. In addition, for the shear wall model an elastic analysis with ductility factors applied was also performed. The objectives of the work were to compare the results between the analyses, and to develop insights regarding the work that would be needed before the displacement based analysis methodology could be considered applicable to facilities licensed by the NRC. A summary of the research results, which were published in NUREGICR-6719 in July 2001, is presented in this paper.

  9. Laboratory displacement with micellar solutions

    Microsoft Academic Search

    1967-01-01

    Slugs of micellar solutions, displaced by thickened water, were evaluated in Berea sandstone cores, previously waterflooded to residual oil saturation. The performance and flow behavior of one of these slugs is described. Flooding performance is remarkable: A 1% pore volume slug recovered 59% of the tertiary oil-in-place, while a 5% pore volume slug recovered 100% of the crude oil from

  10. Large increase in the electron capture and excitation cross sections for Li+ colliding with atomic H under UV laser assistance

    NASA Astrophysics Data System (ADS)

    Domínguez-Gutiérrez, F. J.; Cabrera-Trujillo, R.

    2015-07-01

    Neutralization and ash products due to electron capture processes in plasmas reduce the efficiency of energy generation in fusion Tokamak reactors. Therefore, lithium ions have been used to improve the efficiency of energy generation where good control of the electron capture process is required. Here, we show that an intense (1.4× {{10}13} W cm?2), ultra-short (1 fs at full width half-maximum) Gaussian laser pulse in the UV region can enhance the electron capture process on L{{i}+}+H(1s) in the low collision keV energy region. We find a factor of 10 enhancement in electron capture cross-section at impact energies lower than 10 keV amu?1 for an 80 nm wavelength laser and a factor of 2 for the excitation process in the hydrogen atom as compared to the laser-free case. In contrast, for a 200 nm wavelength laser the increase of the electron capture cross-sections takes place around 1 keV amu?1 by a factor of 3 and no enhancement for the excitation process. Our results show that the UV assisted production of Li can be controlled, particularly for short UV wave-length for a specific collision energy range. We anticipate that our findings will facilitate UV laser control of the Li production in Tokamak reactors and encourage further experimental work in this system.

  11. INFLUENCE OF MASS ON DISPLACEMENT THRESHOLD

    SciTech Connect

    Setyawan, Wahyu; Selby, A.; Nandipati, Giridhar; Roche, Kenneth J.; Kurtz, Richard J.; Wirth, Brian D.

    2014-12-30

    Molecular dynamics simulations are performed to investigate the effect of mass on displacement threshold energy in Cr, Mo, Fe and W. For each interatomic potential, the mass of the atoms is varied among those metals for a total of 16 combinations. The average threshold energy over all crystal directions is calculated within the irreducible crystal directions using appropriate weighting factors. The weighting factors account for the different number of equivalent directions among the grid points and the different solid angle coverage of each grid point. The grid points are constructed with a Miller index increment of 1/24 for a total of 325 points. For each direction, 10 simulations each with a different primary-knock-on atom are performed. The results show that for each interatomic potential, the average threshold energy is insensitive to the mass; i.e., the values are the same within the standard error. In the future, the effect of mass on high-energy cascades for a given interatomic potential will be investigated.

  12. Low-temperature in situ large strain plasticity of ceramic SiC nanowires and its atomic-scale mechanism.

    PubMed

    Han, X D; Zhang, Y F; Zheng, K; Zhang, X N; Zhang, Z; Hao, Y J; Guo, X Y; Yuan, J; Wang, Z L

    2007-02-01

    Large strain plasticity is phenomenologically defined as the ability of a material to exhibit an exceptionally large deformation rate during mechanical deformation. It is a property that is well established for metals and alloys but is rarely observed for ceramic materials especially at low temperature ( approximately 300 K). With the reduction in dimensionality, however, unusual mechanical properties are shown by ceramic nanomaterials. In this Letter, we demonstrated unusually large strain plasticity of ceramic SiC nanowires (NWs) at temperatures close to room temperature that was directly observed in situ by a novel high-resolution transmission electron microscopy technique. The continuous plasticity of the SiC NWs is accompanied by a process of increased dislocation density at an early stage, followed by an obvious lattice distortion, and finally reaches an entire structure amorphization at the most strained region of the NW. These unusual phenomena for the SiC NWs are fundamentally important for understanding the nanoscale fracture and strain-induced band structure variation for high-temperature semiconductors. Our result may also provide useful information for further studying of nanoscale elastic-plastic and brittle-ductile transitions of ceramic materials with superplasticity. PMID:17298014

  13. A wireless laser displacement sensor node for structural health monitoring.

    PubMed

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  14. A Wireless Laser Displacement Sensor Node for Structural Health Monitoring

    PubMed Central

    Park, Hyo Seon; Kim, Jong Moon; Choi, Se Woon; Kim, Yousok

    2013-01-01

    This study describes a wireless laser displacement sensor node that measures displacement as a representative damage index for structural health monitoring (SHM). The proposed measurement system consists of a laser displacement sensor (LDS) and a customized wireless sensor node. Wireless communication is enabled by a sensor node that consists of a sensor module, a code division multiple access (CDMA) communication module, a processor, and a power module. An LDS with a long measurement distance is chosen to increase field applicability. For a wireless sensor node driven by a battery, we use a power control module with a low-power processor, which facilitates switching between the sleep and active modes, thus maximizing the power consumption efficiency during non-measurement and non-transfer periods. The CDMA mode is also used to overcome the limitation of communication distance, which is a challenge for wireless sensor networks and wireless communication. To evaluate the reliability and field applicability of the proposed wireless displacement measurement system, the system is tested onsite to obtain the required vertical displacement measurements during the construction of mega-trusses and an edge truss, which are the primary structural members in a large-scale irregular building currently under construction. The measurement values confirm the validity of the proposed wireless displacement measurement system and its potential for use in safety evaluations of structural elements. PMID:24084114

  15. Dynamic displacement measurement of bridges using vision-based system

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Jae; Fukuda, Yoshio; Shinozuka, Masanobu

    2006-03-01

    Measuring the displacement of flexible bridges directly is difficult particularly on monumental suspension bridges. Since these bridges cross over sea channels or large rivers, installation of conventional devices for displacement measurement is technically not easy and costly, if not impossible. In this study, real-time displacement measurement of bridges was carried out by means of digital image processing techniques. This is innovative, highly cost-effective and easy to implement, and yet maintains the advantages of dynamic measurement and high resolution. First, the measurement point is marked on the bridge with a target panel of known geometry. A commercially available digital video camcorder is installed on a fixed point some distance from the bridge (e.g. on the coast) or on a pier (abutment) of the bridge which can be regarded as a fixed point. The camcorder with a telescopic device installed takes a motion picture of the target marked. Meanwhile, the displacement of the target is calculated using an image processing technique, which requires a target recognition algorithm, projection of the captured image, and calculation of the actual displacement using target geometry and the number of pixels moved. To measure the displacement at multiple locations on the bridge, an effective synchronized vision-based system was developed using master/slave system and wireless data communication. For the purpose of verification, the measured displacement by synchronized vision-based system was compared with the data measured by a contact-type sensor, a linear variable differential transformer (LVDT) from laboratory tests. The displacement measured by the proposed method showed a good agreement with the data from the conventional sensors. A field test on a pedestrian suspension bridge was also carried out to check the feasibility of the proposed system.

  16. Sample displacement batch chromatography of proteins.

    PubMed

    Kotasinska, Marta; Richter, Verena; Kwiatkowski, Marcel; Schlüter, Hartmut

    2014-01-01

    In downstream processing large scale chromatography plays an important role. For its development screening experiments followed by pilot plant chromatography are mandatory steps. Here we describe fast, simple, and inexpensive methods for establishing a preparative chromatography for the separation of complex protein mixtures, based on sample displacement batch chromatography. The methods are demonstrated by anion-exchange chromatography of a human plasma protein fraction (Cohn IV-4), including the screening step and scaling up of the chromatography by a factor of 100. The results of the screening experiments and the preparative chromatography are monitored by SDS-PAGE electrophoresis. In summary we provide a protocol which should be easily adaptable for the chromatographic large scale purification of other proteins, in the laboratory as well as in industry for commercial manufacturing. For the latter these protocols cover the initial piloting steps for establishing a sample batch chromatography based on packed columns rather than batch chromatography. PMID:24648085

  17. Free displacer and Ringbom displacer for a Malone refrigerator

    SciTech Connect

    Swift, G.W.; Brown, A.O.

    1994-05-01

    Malone refrigeration uses a liquid near its critical point (instead of the customary gas) as the working fluid in a Stirling, Brayton, or similar regenerative or recuperative cycle. Thus far, we have focused on the Stirling cycle, to avoid the difficult construction of the high-pressure-difference counterflow recuperator required for a Brayton machine. Our first Malone refrigerator used liquid propylene (C{sub 3}H{sub 6}) in a double-acting 4-cylinder Stirling configuration. First measurements with a free displacer used in a liquid working fluid are presented. The displacer was operated both in harmonic mode and in Ringbom mode, in liquid carbon dioxide. The results are in reasonable agreement with expectations.

  18. Investigations on the development of a mixed displacement-pressure formulation for an anelastic displacement-field finite element

    NASA Astrophysics Data System (ADS)

    Rusovici, Razvan

    2006-03-01

    Space and weapon delivery systems contain guidance components and payload that need to be protected from the extremely harsh acoustic excitation present during launch operations. The above example represents just one application where high-damping viscoelastic materials are used in the design of shock and vibration isolation components. The shock transients generally encountered are characterized by a broad frequency spectrum. Widely available finite element codes do not offer the proper tools to model the frequency- dependent mechanical properties of viscoelastic materials over the frequency domain of interest. An added difficulty is the large Poissson's ratio exhibited by some of these materials, which indicates that previously developed displacement-based finite element formulations should be complemented with mixed pressure-displacement finite element formulations. A pure displacement-based finite element generally predicts the displacements well, if the mesh used is fine enough, but the same thing may not be said about the values of the predicted stresses. The Anelastic Displacement Fields (ADF) method is employed herein to model frequency-dependence of material properties within a time-domain finite element framework and using a mixed displacement-pressure finite element formulation. Finite elements based on this new formulation are developed.

  19. Cold Atoms

    NASA Astrophysics Data System (ADS)

    Bellac, Michel Le

    2014-11-01

    This chapter and the following one address collective effects of quantum particles, that is, the effects which are observed when we put together a large number of identical particles, for example, electrons, helium-4 or rubidium-85 atoms. We shall see that quantum particles can be classified into two categories, bosons and fermions, whose collective behavior is radically different. Bosons have a tendency to pile up in the same quantum state, while fermions have a tendency to avoid each other. We say that bosons and fermions obey two different quantum statistics, the Bose-Einstein and the Fermi-Dirac statistics, respectively. Temperature is a collective effect, and in Section 5.1 we shall explain the concept of absolute temperature and its relation to the average kinetic energy of molecules. We shall describe in Section 5.2 how we can cool atoms down thanks to the Doppler effect, and explain how cold atoms can be used to improve the accuracy of atomic clocks by a factor of about 100. The effects of quantum statistics are prominent at low temperatures, and atom cooling will be used to obtain Bose-Einstein condensates at low enough temperatures, when the atoms are bosons.

  20. Atomic structure from large-area, low-dose exposures of materials: A new route to circumvent radiation damage?

    PubMed Central

    Meyer, J.C.; Kotakoski, J.; Mangler, C.

    2014-01-01

    Beam-induced structural modifications are a major nuisance in the study of materials by high-resolution electron microscopy. Here, we introduce a new approach to circumvent the radiation damage problem by a statistical treatment of large, noisy, low-dose data sets of non-periodic configurations (e.g. defects) in the material. We distribute the dose over a mixture of different defect structures at random positions and with random orientations, and recover representative model images via a maximum likelihood search. We demonstrate reconstructions from simulated images at such low doses that the location of individual entities is not possible. The approach may open a route to study currently inaccessible beam-sensitive configurations. PMID:24315660

  1. Polybenzimidazole via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergenrother, Paul M. (Inventor); Smith, Joseph G. (Inventor)

    1994-01-01

    Di(hydroxyphenyl)benzimidazole monomers were prepared from phenyl-4-hydroxybenzoate and aromatic bis(o-diamine)s. These monomers were used in the synthesis of soluble polybenzimidazoles. The reaction involved the aromatic nucleophilic displacement of various di(hydroxyphenyl)benzimidazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds in the presence of an alkali metal base. These polymers exhibited lower glass transition temperatures, improved solubility, and better compression moldability over their commercial counterparts.

  2. Upscaling of Miscible Displacement Processes

    Microsoft Academic Search

    Dengen Zhou; Jairam Kamath; Lou Durlofsky; Erling H. Stenby

    In this paper, we present an approach for upscaling miscible displacement processes using a modified Todd-Longstaff (T-L) formulation. The T-L formulation is modified to include pseudo fractional flow curves. The pseudo fractional flow curves are calculated for each upscaled grid using the upscaling technique proposed by Christie et al.1 The new procedure is applied to a 2-D cross-section model. We

  3. Multiple displacement amplification improves PGD for fragile X syndrome

    Microsoft Academic Search

    P. Burlet; N. Frydman; N. Gigarel; V. Kerbrat; G. Tachdjian; E. Feyereisen; J.-P. Bonnefont; R. Frydman; A. Munnich; J. Steffann

    2006-01-01

    We report an improvement in the PGD test for fragile X syndrome (FXS). Recently, multiple displacement amplification (MDA) has been reported to yield large amounts of DNA from single cells. Taking into account this technique, we developed a new PGD test for FXS, enabling combined analysis of linked polymorphic markers with the study of the non-expanded CGG repeat. Single cell

  4. A Note from Bosnia and Herzegovina: Leading a Displaced Life

    Microsoft Academic Search

    Inela Selimovic

    2011-01-01

    Upon revisiting 11 July 1995 in Srebrenica, Bosnia and Herzegovina (BiH), this piece reflects on a group of the Srebrenica genocide survivors as they continue through, as well as, struggle with their healing processes as internally displaced persons in a small village near Sarajevo. Largely left on their own since 1995, these families' existence has significantly depended on the humane

  5. A Note from Bosnia and Herzegovina: Leading a Displaced Life

    Microsoft Academic Search

    Inela Selimovic

    2011-01-01

    :Upon revisiting 11 July 1995 in Srebrenica, Bosnia and Herzegovina (BiH), this piece reflects on a group of the Srebrenica genocide survivors as they continue through, as well as, struggle with their healing processes as internally displaced persons in a small village near Sarajevo. Largely left on their own since 1995, these families' existence has significantly depended on the humane

  6. Gamma displacement cross-sections in various materials

    E-print Network

    Motta, Arthur T.

    Electric (GE) Advanced Boiling Water Reactor (ABWR) indicated that the calculated gamma displacement damage of reactor pressure vessel (RPV) steels in the HFIR reactor (Rehn and Birtcher, 1993; Farrell et al. 1994 there is a large water gap, gamma damage can become comparable to that produced by neutrons, on a straight

  7. Optimal optical measurement of small displacements

    Microsoft Academic Search

    Magnus T. L. Hsu; Vincent Delaubert; Ping Koy Lam; Warwick P. Bowen

    2004-01-01

    We derive the quantum noise limit for the optical beam displacement of a TEM00 mode. Using a multimodal analysis, we show that the conventional split detection scheme for measuring beam displacement is non-optimal with ~80% efficiency. We propose a new displacement measurement scheme that is optimal for small beam displacement. This scheme utilizes a homodyne detection set-up that has a

  8. Optimum Small Optical Beam Displacement Measurement

    Microsoft Academic Search

    Magnus T. L. Hsu; Vincent Delaubert; Ping Koy Lam; Warwick Bowen

    2004-01-01

    We derive the quantum noise limit for the optical beam displacement of a\\u000aTEM00 mode. Using a multimodal analysis, we show that the conventional split\\u000adetection scheme for measuring beam displacement is non-optimal with 80%\\u000aefficiency. We propose a new displacement measurement scheme that is optimal\\u000afor small beam displacement. This scheme utilises a homodyne detection setup\\u000athat has a

  9. Optimal optical measurement of small displacements

    Microsoft Academic Search

    Magnus T L Hsu; Vincent Delaubert; Ping Koy Lam; Warwick P Bowen

    2004-01-01

    We derive the quantum noise limit for the optical beam displacement of a TEM00 mode. Using a multimodal analysis, we show that the conventional split detection scheme for measuring beam displacement is non-optimal with ?80% efficiency. We propose a new displacement measurement scheme that is optimal for small beam displacement. This scheme utilizes a homodyne detection set-up that has a

  10. Displacement chromatography of isomers and therapeutic compounds

    Microsoft Academic Search

    Yan Qi; Junxiong Huang

    2002-01-01

    Displacement chromatography was successfully used to separate a binary isomer mixture, epirubicin and doxorubicin, on Kromasil KR100-10 C18 250×4.6 mm I.D. (10 ?m) column. Displacement parameters such as the types and the concentrations of displacer, the composition and the flow rate of the mobile phase were critically examined in this study. The displacer employed was 30 mg\\/ml benzethonium chloride. Loading

  11. Water Mist Suppression in Conjunction with Displacement

    E-print Network

    Hickman, Mark

    Water Mist Suppression in Conjunction with Displacement Ventilation By Benjamin Piers Hume-2758 #12;#12;Displacement Water Mist System Masters of Fire Engineering Thesis 2003 i A man of genius makes Water Mist System Masters of Fire Engineering Thesis 2003 ii #12;Displacement Water Mist System Masters

  12. Torsional stress measurement by axial displacement

    Microsoft Academic Search

    J. J. Deer

    1971-01-01

    An apparatus is described for the measurement of torque by converting angular displacement to axial displacement. A stress-responsive pulley is loosely mounted on a drive shaft by a plain bearing and a short screw-threaded section. The pulley is attached to the shaft by means of a torsion spring. In use a retarding effect upon the pulley causes angular displacement within

  13. Study of the fragmentation of a displacement cascade in subcascades within the Binary Collision Approximation framework

    SciTech Connect

    Luneville, Laurence [CEA, Saclay, France; Simone, David [CEA, Saclay, France; Weber, William J [ORNL

    2011-01-01

    When a material is subjected to irradiation, many primary defects are cre- ated at the atomic level by sequences of ballistic collision events to form highly disordered regions defined as displacement cascades. The long term evolution of materials under irradiation is dictated by the number and the spatial distribution of the surviving defects in the displacement cascade. The peculiar power law shape of collision cross sections is responsible for the frag- mentation of a displacement cascade into smaller subcascades. However, it remains difficult to define a subcascade. Within the fractal geometry frame- work, we demonstrate in this work that the set of atomic trajectories in a displacement cascade exhibit a fractal behavior. From this analysis, we present a new criterion to describe the fragmentation of a displacement cas- cade and to calculate the distribution and the number of defects from this fragmentation. Such an analysis provides the natural framework to estimate the number of defects created in a displacement cascade to integrate with results of MD simulations. From this defiintion of the fragmentation of a displacement cascade, this work gives some new insights to describe both the primary defects produced in a material under irradiation and then to compare different irradiations performed with different particles.

  14. Agent-Based and Population-Based Simulation of Displacement of Crime (extended abstract)

    E-print Network

    Bosse, Tibor

    Agent-Based and Population-Based Simulation of Displacement of Crime (extended abstract) Tibor are agent-based. However, when the number of agents considered becomes large, population-based simulation-based and a population-based simulation model of crime displacement, and reports a comparative evaluation of the two

  15. Juvenile Songbirds Compensate for Displacement to Oceanic Islands during Autumn Migration

    PubMed Central

    Thorup, Kasper; Ortvad, Troels Eske; Rabøl, Jørgen; Holland, Richard A.; Tøttrup, Anders P.; Wikelski, Martin

    2011-01-01

    To what degree juvenile migrant birds are able to correct for orientation errors or wind drift is still largely unknown. We studied the orientation of passerines on the Faroe Islands far off the normal migration routes of European migrants. The ability to compensate for displacement was tested in naturally occurring vagrants presumably displaced by wind and in birds experimentally displaced 1100 km from Denmark to the Faroes. The orientation was studied in orientation cages as well as in the free-flying birds after release by tracking departures using small radio transmitters. Both the naturally displaced and the experimentally displaced birds oriented in more easterly directions on the Faroes than was observed in Denmark prior to displacement. This pattern was even more pronounced in departure directions, perhaps because of wind influence. The clear directional compensation found even in experimentally displaced birds indicates that first-year birds can also possess the ability to correct for displacement in some circumstances, possibly involving either some primitive form of true navigation, or ‘sign posts’, but the cues used for this are highly speculative. We also found some indications of differences between species in the reaction to displacement. Such differences might be involved in the diversity of results reported in displacement studies so far. PMID:21464975

  16. Optimum Small Optical Beam Displacement Measurement

    E-print Network

    Hsu, M T L; Lam, P K; Bowen, W P; Hsu, Magnus T.L.; Delaubert, Vincent; Lam, Ping Koy; Bowen, Warwick

    2004-01-01

    We derive the quantum noise limit for the optical beam displacement of a TEM00 mode. Using a multimodal analysis, we show that the conventional split detection scheme for measuring beam displacement is non-optimal with 80% efficiency. We propose a new displacement measurement scheme that is optimal for small beam displacement. This scheme utilises a homodyne detection setup that has a TEM10 mode local oscillator. We show that although the quantum noise limit to displacement measurement can be surpassed using squeezed light in appropriate spatial modes for both schemes, the TEM10 homodyning scheme out-performs split detection for all values of squeezing.

  17. Optimum Small Optical Beam Displacement Measurement

    E-print Network

    Magnus T. L. Hsu; Vincent Delaubert; Ping Koy Lam; Warwick Bowen

    2004-07-27

    We derive the quantum noise limit for the optical beam displacement of a TEM00 mode. Using a multimodal analysis, we show that the conventional split detection scheme for measuring beam displacement is non-optimal with 80% efficiency. We propose a new displacement measurement scheme that is optimal for small beam displacement. This scheme utilises a homodyne detection setup that has a TEM10 mode local oscillator. We show that although the quantum noise limit to displacement measurement can be surpassed using squeezed light in appropriate spatial modes for both schemes, the TEM10 homodyning scheme out-performs split detection for all values of squeezing.

  18. Antiprotonic Helium Atoms

    E-print Network

    O. I. Kartavtsev

    1995-07-22

    Metastable antiprotonic helium atoms $^{3,4}\\! H\\! e\\bar pe$ have been discovered recently in experiments of the delayed annihilation of antiprotons in helium media. These exotic atoms survive for an enormous time (about tens of microseconds) and carry the extremely large total angular momentum $L\\sim 30-40$. The theoretical treatment of the intrinsic properties of antiprotonic helium atoms, their formation and collisions with atoms and molecules is discussed.

  19. A Theoretical Model to Predict Both Horizontal Displacement and Vertical Displacement for Electromagnetic Induction-Based Deep Displacement Sensors

    PubMed Central

    Shentu, Nanying; Zhang, Hongjian; Li, Qing; Zhou, Hongliang; Tong, Renyuan; Li, Xiong

    2012-01-01

    Deep displacement observation is one basic means of landslide dynamic study and early warning monitoring and a key part of engineering geological investigation. In our previous work, we proposed a novel electromagnetic induction-based deep displacement sensor (I-type) to predict deep horizontal displacement and a theoretical model called equation-based equivalent loop approach (EELA) to describe its sensing characters. However in many landslide and related geological engineering cases, both horizontal displacement and vertical displacement vary apparently and dynamically so both may require monitoring. In this study, a II-type deep displacement sensor is designed by revising our I-type sensor to simultaneously monitor the deep horizontal displacement and vertical displacement variations at different depths within a sliding mass. Meanwhile, a new theoretical modeling called the numerical integration-based equivalent loop approach (NIELA) has been proposed to quantitatively depict II-type sensors’ mutual inductance properties with respect to predicted horizontal displacements and vertical displacements. After detailed examinations and comparative studies between measured mutual inductance voltage, NIELA-based mutual inductance and EELA-based mutual inductance, NIELA has verified to be an effective and quite accurate analytic model for characterization of II-type sensors. The NIELA model is widely applicable for II-type sensors’ monitoring on all kinds of landslides and other related geohazards with satisfactory estimation accuracy and calculation efficiency. PMID:22368467

  20. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1995-05-30

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 29 figs.

  1. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, John (M.I.T. P.O. Box 397301, Cambridge, MA 02139)

    1999-01-01

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically.

  2. Interferometric fiber optic displacement sensor

    DOEpatents

    Farah, J.

    1999-04-06

    A method is presented to produce a change in the optical path length in the gap between two single mode optical fibers proportional to the lateral displacement of either fiber end normal to its axis. This is done with the use of refraction or diffraction at the interface between a guiding and non-guiding media to change the direction of propagation of the light in the gap. A method is also presented for laying a waveguide on a cantilever so that the displacement of the tip of the cantilever produces a proportional path length change in the gap by distancing the waveguide from the neutral axis of the cantilever. The fiber is supported as a cantilever or a waveguide is deposited on a micromachined cantilever and incorporated in an interferometer which is made totally on a silicon substrate with the use of integrated-optic technology. A resonant element in the form of a micro-bridge is incorporated in the ridge waveguide and produces a frequency output which is readily digitizeable and immune to laser frequency noise. Finally, monolithic mechanical means for phase modulation are provided on the same sensor substrate. This is done by vibrating the cantilever or micro-bridge either electrically or optically. 23 figs.

  3. Genetics of bovine abomasal displacement.

    PubMed

    Zerbin, Ina; Lehner, Stefanie; Distl, Ottmar

    2015-04-01

    Displacement of the abomasum (DA) is a common inherited condition in Holstein cows. This article reviews the genetics of DA including risk factors, genetic parameters and molecular genetic results. Breeds other than Holsteins affected by DA include Guernseys, Jerseys, Brown Swiss, Ayrshires and Simmental-Red Holsteins. In most DA cases, left displacements of the abomasum (LDA) are seen. Lactation incidence rates are higher for DA in first lactation Holsteins compared to later lactations. For Holstein cows, heritability estimates for DA are between 0.03 and 0.53. Genetic correlation estimates among DA and milk production traits range from positive to negative. Genome-wide significant genomic regions associated with LDA are located on bovine chromosomes (BTA) 1, 3, 11, 20 and 23. Motilin-associated single nucleotide polymorphisms on BTA23 exhibit a functional relationship with LDA. Pathways for deposition of calcium, insulin-dependent diabetes mellitus and synaptic transmission are significantly related to LDA in Holsteins. Deciphering the DA-associated genomic regions and genes may be an important step in the quest to understand the underlying disease-causing mechanisms and in unravelling mutations with a causal relationship to DA. PMID:25840863

  4. Character displacement in the fighting colours of Hetaerina damselflies.

    PubMed

    Anderson, Christopher N; Grether, Gregory F

    2010-12-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. PMID:20591870

  5. Character displacement in the fighting colours of Hetaerina damselflies

    PubMed Central

    Anderson, Christopher N.; Grether, Gregory F.

    2010-01-01

    Aggression between species is a seldom-considered but potentially widespread mechanism of character displacement in secondary sexual characters. Based on previous research showing that similarity in wing coloration directly influences interspecific territorial aggression in Hetaerina damselflies, we predicted that wing coloration would show a pattern of character displacement (divergence in sympatry). A geographical survey of four Hetaerina damselfly species in Mexico and Texas showed evidence for character displacement in both species pairs that regularly occurs sympatrically. Hetaerina titia, a species that typically has large black wing spots and small red wing spots, shifted to having even larger black spots and smaller red wing spots at sites where a congener with large red wing spots is numerically dominant (Hetaerina americana or Hetaerina occisa). Hetaerina americana showed the reverse pattern, shifting towards larger red wing spots where H. titia is numerically dominant. This pattern is consistent with the process of agonistic character displacement, but the ontogenetic basis of the shift remains to be demonstrated. PMID:20591870

  6. Role of W and Mn for reliable 1X nanometer-node ultra-large-scale integration Cu interconnects proved by atom probe tomography

    SciTech Connect

    Shima, K.; Shimizu, H.; Momose, T.; Shimogaki, Y. [Department of Materials Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan); Tu, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Key Laboratory of Polar Materials and Devices, Ministry of Education, East China Normal University, Shanghai 200241 (China); Takamizawa, H.; Shimizu, Y.; Inoue, K.; Nagai, Y. [The Oarai Center, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan)

    2014-09-29

    We used atom probe tomography (APT) to study the use of a Cu(Mn) as a seed layer of Cu, and a Co(W) single-layer as reliable Cu diffusion barriers for future interconnects in ultra-large-scale integration. The use of Co(W) layer enhances adhesion of Cu to prevent electromigration and stress-induced voiding failures. The use of Cu(Mn) as seed layer may enhance the diffusion barrier performance of Co(W) by stuffing the Cu diffusion pass with Mn. APT was used to visualize the distribution of W and Mn in three dimensions with sub-nanometer resolution. W was found to segregate at the grain boundaries of Co, which prevents diffusion of Cu via the grain boundaries. Mn was found to diffuse from the Cu(Mn) layer to Co(W) layer and selectively segregate at the Co(W) grain boundaries with W, reinforcing the barrier properties of Co(W) layer. Hence, a Co(W) barrier coupled with a Cu(Mn) seed layer can form a sufficient diffusion barrier with film that is less than 2.0-nm-thick. The diffusion barrier behavior was preserved following a 1-h annealing at 400?°C. The underlayer of the Cu interconnects requires a large adhesion strength with the Cu, as well as low electrical resistivity. The use of Co(W) has previously been shown to satisfy these requirements, and addition of Mn is not expected to deteriorate these properties.

  7. Polybenzimidazoles Via Aromatic Nucleophilic Displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Hergerrother, Paul M. (Inventor); Smith, Joseph G., Jr. (Inventor)

    1997-01-01

    Novel molecular weight controlled and endcapped polybenzimidazoles (PBI) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenylbenzimidazole) monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The PBI are endcapped with mono(hydroxyphenyl)benzimidazoles. The polymerizations are carried out in polar aprotic solvents such as N-methyl-2-pyrrolidinone or N,N-dimethylacetamide using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. Mono(hydroxyphenyl)benzimidazoles are synthesized by reacting phenyl-4-hydroxybenzoate with aromatic (o-diamine)s in diphenylsulfone. Molecular weight controlled and endcapped PBI of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

  8. Displaceable Gear Torque Controlled Driver

    NASA Technical Reports Server (NTRS)

    Cook, Joseph S., Jr. (Inventor)

    1997-01-01

    Methods and apparatus are provided for a torque driver including a displaceable gear to limit torque transfer to a fastener at a precisely controlled torque limit. A biasing assembly biases a first gear into engagement with a second gear for torque transfer between the first and second gear. The biasing assembly includes a pressurized cylinder controlled at a constant pressure that corresponds to a torque limit. A calibrated gage and valve is used to set the desired torque limit. One or more coiled output linkages connect the first gear with the fastener adaptor which may be a socket for a nut. A gear tooth profile provides a separation force that overcomes the bias to limit torque at the desired torque limit. Multiple fasteners may be rotated simultaneously to a desired torque limit if additional output spur gears are provided. The torque limit is adjustable and may be different for fasteners within the same fastener configuration.

  9. SMA-based smart damper/displacement transducer

    NASA Astrophysics Data System (ADS)

    Mao, Chen-xi; Li, Hui

    2005-05-01

    An innovative smart shape memory alloy (SMA) -based damper/displacement transducer, which had comprehensive energy dissipation and strain self-sensing abilities (i.e. electric resistance vs. applied strain relationship) simultaneously, was proposed in this paper. This smart SMA-based damper/displacement transducer had three characteristics: 1) SMA wires in the damper/transducer were always elongated during the entire excitation; 2) SMA wires dissipated energy with re-centering ability due to pseudoelasticity; 3) SMA damper/transducer could simultaneously play the role of displacement transducer due to the strain self-sensing property of SMA wires in the damper. Such smart SMA-based damper/displacement transducer, incorporated into a building or a bridge, provided the potential to rapidly assess post-earthquake safety of structures. A large number of tests were conducted firstly, on the hysteresis stress-strain-electric resistance relationship of NiTi SMA wires (diameter 1.2mm). These tests were carried out under sinusoidal excitations with different loading frequencies at room temperature. The experimental results indicated that the pseudoelastic hysteresis loops of the SMA wires were dependent on loading frequency. In addition, the sensitivity coefficient of electric resistance vs. applied strain of the NiTi wires was identified to be 6.466 from the test results, which was independent of the loading frequency. Finally, shake table tests for a scaled 5-story steel frame, with the said smart SMA dampers/displacement transducers at the first story, subjected to various earthquake excitations, were conducted. The results of the shake table tests indicated that not only could the smart SMA damper/displacement transducers suppress structural seismic response effectively, but also it could monitor structural interstory drifts accurately.

  10. Fiber optic multimode displacement sensor

    NASA Astrophysics Data System (ADS)

    Fisher, Karl A.; Jarzynski, Jacek

    1996-04-01

    An underwater Optical Motion Sensor (OMS) based on a design first presented by W. B. Spillman, Schlieren multimode fiber-optic hydrophone, Applied Physics Letters 37(2), 15 July 1980, p. 145-146 is described. The displacement sensor uses the same acoustooptical intensity modulation mechanism as Spillman, however the sensing mechanism is isolated from the ambient fluid environment by a small cylindrical aluminum enclosure (1? OD×3/4?). The enclosure contains an inertial mass and the fiber collimators. The inertial mass is suspended in the center of the enclosure by three small wires rigidly mounted to the walls. The mass and wires act as a cantilever beam system with a mechanical resonance near 100 Hz. The transduction mechanism consists of two opposed optical gratings aligned and positioned between the fiber collimators. One grating is mounted on the inertial mass while the other is mounted on the lower end cap of the enclosure. Relative motion between the gratings causes a modulation of the light transmitted through the gratings. The modulated beam is focused onto a photodetector and converted to electric current. The frequency response is flat from 200 Hz-9 kHz with a minimum detectable displacement of 0.002 A and the dynamic range is 136 dB. The small size and light weight give the sensor an effective density of 1.08 g/cm3 making it almost neutrally buoyant in water. This in conjunction with the performance characteristics make this sensor suitable for use in acoustical sensing applications.

  11. Accurate measurement of electron beam induced displacement cross sections for single-layer graphene.

    PubMed

    Meyer, Jannik C; Eder, Franz; Kurasch, Simon; Skakalova, Viera; Kotakoski, Jani; Park, Hye Jin; Roth, Siegmar; Chuvilin, Andrey; Eyhusen, Sören; Benner, Gerd; Krasheninnikov, Arkady V; Kaiser, Ute

    2012-05-11

    We present an accurate measurement and a quantitative analysis of electron-beam-induced displacements of carbon atoms in single-layer graphene. We directly measure the atomic displacement ("knock-on") cross section by counting the lost atoms as a function of the electron-beam energy and applied dose. Further, we separate knock-on damage (originating from the collision of the beam electrons with the nucleus of the target atom) from other radiation damage mechanisms (e.g., ionization damage or chemical etching) by the comparison of ordinary (12C) and heavy (13C) graphene. Our analysis shows that a static lattice approximation is not sufficient to describe knock-on damage in this material, while a very good agreement between calculated and experimental cross sections is obtained if lattice vibrations are taken into account. PMID:23003063

  12. Displacement of crude oil by carbon dioxide 

    E-print Network

    Omole, Olusegun

    1980-01-01

    DISPLACEMENT OF CRUDE OIL BY CARBON DIOXIDE A Thesis by OLUSEGUN OMOLE Submitted to the Graduate College of Texas ASM University in part';al fulfillment of the requirement for the degree of MASTER OF SCIENCE December 1980 Major Subject...: Petroleum Engineering DISPLACEMENT OF CRUDE OIL BY CARBON DIOXIDE A Thesis by OLUSEGUN OMOLE Approved as to style and content by: hairman of Committee / (Member (Member (Member (Hea o Depart ent December 1980 ABSTRACT Displacement of Crude Oil...

  13. Microbial Adhesion in Flow Displacement Systems

    PubMed Central

    Busscher, Henk J.; van der Mei, Henny C.

    2006-01-01

    Flow displacement systems are superior to many other (static) systems for studying microbial adhesion to surfaces because mass transport and prevailing shear conditions can be adequately controlled and notoriously ill-defined slight rinsing steps to remove so-called “loosely adhering organisms” can be avoided. In this review, we present the basic background required to calculate mass transport and shear rates in flow displacement systems, focusing on the parallel plate flow chamber as an example. Critical features in the design of flow displacement systems are discussed, as well as different strategies for data analysis. Finally, selected examples of working with flow displacement systems are given for diverse biomedical applications. PMID:16418527

  14. Real-time detection of linear and angular displacements with a modified DVD optical head

    Microsoft Academic Search

    En-Te Hwu; Shao-Kang Hung; Chih-Wen Yang; Kuang-Yuh Huang; Ing-Shouh Hwang

    2008-01-01

    Here we demonstrate that an astigmatic detection system (ADS), constructed with a modified digital-versatile-disk (DVD) optical head, can achieve real-time measurement of a linear displacement and two-dimensional (2D) tilt angles with a high sensitivity. An atomic force microscope (AFM), using our detection system to sense the deflection of microfabricated cantilevers, can resolve single atomic steps on graphite surfaces with a

  15. Intrinsic Mean Square Displacement in Proteins

    NASA Astrophysics Data System (ADS)

    Vural, Derya; Glyde, Henry R.

    2012-02-01

    The dynamics of biological molecules is investigated in neutron scattering experiments, in molecular dynamics simulations, and using analytical theory. Specifically, the mean square displacement (MSD), exp, of hydrogen in proteins is determined from measurements of the incoherent elastic neutron scattering intensity (ENSI). The MSD, exp, is usually obtained from the dependence of the ENSI on the scattering wave vector Q. The MSD increases with increasing temperature reaching large values at room temperature. Large MSD is often associated with and used as an indicator of protein function. The observed MSD, however, depends on the energy resolution of the neutron spectrometer employed. We present a method, a first attempt, to extract the intrinsic MSD of hydrogen in protein from measurements, one that is independent of the instrument resolution. The method consists of a model of the ENSI that contains (1) the intrinsic MSD, (2) the instrument resolution width and (3) a parameter describing the motional processes that contribute to the MSD. Several examples of intrinsic MSDs in proteins obtained from fitting to data in the existing literature will be presented.

  16. Atom-Photon Entanglement

    E-print Network

    Juergen Volz; Markus Weber; Daniel Schlenk; Wenjamin Rosenfeld; Johannes Vrana; Karen Saucke; Christian Kurtsiefer; Harald Weinfurter

    2005-11-18

    We report the observation of entanglement between a single trapped atom and a single photon at a wavelength suitable for low-loss communication over large distances, thereby achieving a crucial step towards long range quantum networks. To verify the entanglement we introduce a single atom state analysis. This technique is used for full state tomography of the atom-photon qubit-pair. The detection efficiency and the entanglement fidelity are high enough to allow in a next step the generation of entangled atoms at large distances, ready for a final loophole-free Bell experiment.

  17. Icosahedral quasicrystals as twins of cubic crystals containing large icosahedral clusters of atoms: The 1012-atom primitive cubic structure of Al6CuLi3, the C-phase Al37Cu3Li21Mg3, and GaMg2Zn3

    PubMed Central

    Pauling, Linus

    1988-01-01

    Single-grain precession x-ray diffraction photographs of Al6CuLi3 have been successfully indexed on the basis of icosahedral twinning of cubic crystals with a 1012-atom primitive cubic unit with edge 25.70 Å, giving support to the proposal that the so-called icosahedral quasicrystals are twins of crystals containing eight large icosahedral clusters in the ?-W arrangement. In this compound two of the clusters consist of 104 atoms and six consist of 136 atoms, with 24 atoms shared. The same structure is assigned to the C-phase, Al37Cu3Li21Mg3, and to GaMg2Zn3. A theory of icosahedral quasicrystals and amorphous metals is described. PMID:16593929

  18. Defect structures induced by high-energy displacement cascades in ? uranium

    NASA Astrophysics Data System (ADS)

    Miao, Yinbin; Beeler, Benjamin; Deo, Chaitanya; Baskes, Michael I.; Okuniewski, Maria A.; Stubbins, James F.

    2015-01-01

    Displacement cascade simulations were conducted for the ? uranium system based on molecular dynamics. A recently developed modified embedded atom method (MEAM) potential was employed to replicate the atomic interactions while an embedded atom method (EAM) potential was adopted to help characterize the defect structures induced by the displacement cascades. The atomic displacement process was studied by providing primary knock-on atoms (PKAs) with kinetic energies from 1 keV to 50 keV. The influence of the PKA incident direction was examined. The defect structures were analyzed after the systems were fully relaxed. The states of the self-interstitial atoms (SIAs) were categorized into various types of dumbbells, the crowdion, and the octahedral interstitial. The voids were determined to have a polyhedral shape with {1 1 0} facets. The size distribution of the voids was also obtained. The results of this study not only expand the knowledge of the microstructural evolution in irradiated ? uranium, but also provide valuable references for the radiation-induced defects in uranium alloy fuels.

  19. Displacive radiation-induced structural contraction in nanocrystalline ZrN

    NASA Astrophysics Data System (ADS)

    Lu, Fengyuan; Huang, Mengbing; Yaqoob, Faisal; Lang, Maik; Namavar, Fereydoon; Trautmann, Christina; Sun, Hongtao; Ewing, Rodney C.; Lian, Jie

    2012-07-01

    Nanocrystalline ZrN thin films with 5 nm grain size, prepared by ion beam assisted deposition, maintained their isometric structure upon intensive displacive and ionizing irradiations, indicating an extremely high stability similar to bulk ZrN. However, a unique structural contraction up to 1.42% in lattice parameter occurred only in nano-sized ZrN upon displacive irradiations. A significant nitrogen loss occurred with reduced N:Zr atomic ratio to 0.88, probably due to the production of displaced nitrogen atoms and fast diffusion along grain boundaries in nanocrystalline ZrN matrix. The accumulation of nitrogen vacancies and related strain relaxation may be responsible for the structural contraction.

  20. Displacive radiation-induced structural contraction in nanocrystalline ZrN

    SciTech Connect

    Lu Fengyuan; Sun Hongtao; Lian Jie [Department of Mechanical, Aerospace and Nuclear Engineering, Rensselaer Polytech Institute, Troy, New York 12180 (United States); Huang, Mengbing; Yaqoob, Faisal [Ion Beam Laboratory, University at Albany-SUNY, Albany, New York 12222 (United States); Lang, Maik; Ewing, Rodney C. [Departments of Earth and Environmental Sciences and Materials Sciences and Engineering, University of Michigan, Ann Arbor, Michigan 48109-1005 (United States); Namavar, Fereydoon [Department of Orthopaedic Surgery and Rehabilitation, University of Nebraska Medical Center, Omaha, Nebraska 68198 (United States); Trautmann, Christina [GSI Helmholtz Center for Heavy Ion Research, 64291 Darmstadt (Germany); Technische Universitaet Darmstadt, 64289 Darmstadt (Germany)

    2012-07-23

    Nanocrystalline ZrN thin films with 5 nm grain size, prepared by ion beam assisted deposition, maintained their isometric structure upon intensive displacive and ionizing irradiations, indicating an extremely high stability similar to bulk ZrN. However, a unique structural contraction up to 1.42% in lattice parameter occurred only in nano-sized ZrN upon displacive irradiations. A significant nitrogen loss occurred with reduced N:Zr atomic ratio to 0.88, probably due to the production of displaced nitrogen atoms and fast diffusion along grain boundaries in nanocrystalline ZrN matrix. The accumulation of nitrogen vacancies and related strain relaxation may be responsible for the structural contraction.

  1. Resolution Quality and Atom Positions in Sub-Angstrom Electron Microscopy

    SciTech Connect

    O'Keefe, Michael A.; Allard, Lawrence F.; Blom, Douglas A.

    2005-02-15

    Ability to determine whether an image peak represents one single atom or several depends on resolution of the HR-(S)TEM. Rayleigh's resolution criterion, an accepted standard in optics, was derived as a means for judging when two image intensity peaks from two sources of light (stars) are distinguishable from a single source. Atom spacings closer than the Rayleigh limit have been resolved in HR-TEM, suggesting that it may be useful to consider other limits, such as the Sparrow resolution criterion. From the viewpoint of the materials scientist, it is important to be able to use the image to determine whether an image feature represents one or more atoms (resolution), and where the atoms (or atom columns) are positioned relative to one another (resolution quality). When atoms and the corresponding image peaks are separated by more than the Rayleigh limit of the HR-(S)TEM, it is possible to adjust imaging parameters so that relative peak positions in the image correspond to relative atom positions in the specimen. When atoms are closer than the Rayleigh limit, we must find the relationship of the peak position to the atom position by peak fitting or, if we have a suitable model, by image simulation. Our Rayleigh-Sparrow parameter QRS reveals the ''resolution quality'' of a microscope image. QRS values greater than 1 indicate a clearly resolved twin peak, while values between 1 and 0 mean a lower-quality resolution and an image with peaks displaced from the relative atom positions. The depth of the twin-peak minimum can be used to determine the value of QRS and the true separation of the atom peaks that sum to produce the twin peak in the image. The Rayleigh-Sparrow parameter can be used to refine relative atom positions in defect images where atoms are closer than the Rayleigh limit of the HR-(S)TEM, reducing the necessity for full image simulations from large defect models.

  2. Effects of Fault Displacement on Emplacement Drifts

    SciTech Connect

    F. Duan

    2000-04-25

    The purpose of this analysis is to evaluate potential effects of fault displacement on emplacement drifts, including drip shields and waste packages emplaced in emplacement drifts. The output from this analysis not only provides data for the evaluation of long-term drift stability but also supports the Engineered Barrier System (EBS) process model report (PMR) and Disruptive Events Report currently under development. The primary scope of this analysis includes (1) examining fault displacement effects in terms of induced stresses and displacements in the rock mass surrounding an emplacement drift and (2 ) predicting fault displacement effects on the drip shield and waste package. The magnitude of the fault displacement analyzed in this analysis bounds the mean fault displacement corresponding to an annual frequency of exceedance of 10{sup -5} adopted for the preclosure period of the repository and also supports the postclosure performance assessment. This analysis is performed following the development plan prepared for analyzing effects of fault displacement on emplacement drifts (CRWMS M&O 2000). The analysis will begin with the identification and preparation of requirements, criteria, and inputs. A literature survey on accommodating fault displacements encountered in underground structures such as buried oil and gas pipelines will be conducted. For a given fault displacement, the least favorable scenario in term of the spatial relation of a fault to an emplacement drift is chosen, and the analysis is then performed analytically. Based on the analysis results, conclusions are made regarding the effects and consequences of fault displacement on emplacement drifts. Specifically, the analysis will discuss loads which can be induced by fault displacement on emplacement drifts, drip shield and/or waste packages during the time period of postclosure.

  3. Asymptotic regimes in unstable miscible displacements in random porous media

    Microsoft Academic Search

    Z. M. Yang; Y. C. Yortsos; Dominique Salin

    2002-01-01

    We study two asymptotic regimes of unstable miscible displacements in porous media, in the two limits, where a permeability-modified aspect ratio, RL=L\\/H(kv\\/kh)1\\/2, becomes large or small, respectively. The first limit is known as transverse (or vertical) equilibrium, the second leads to the problem of non-communicating layers (the Dykstra–Parsons problem). In either case, the problem reduces to the solution of a

  4. Sequence combining of pulsed lasers using refraction-beam-displacement.

    PubMed

    Xu, Jian; Gao, Hongwei; Xu, Yiting; Bo, Yong; Peng, Qinjun; Zhang, Jingyuan; Cui, Dafu; Xu, Zuyan

    2013-01-10

    We present an approach for effectively combining high-power pulsed lasers based on a refraction displacement pulse combining technique. This approach allows for lasers combining with various repetition rates, pulse duration, polarization, output power, and wavelength. The maximum number of lasers that can be combined mainly depends on their repetition rate and pulse duration. This approach is a feasible way to combine a large number of high average power lasers while maintaining good beam quality. PMID:23314636

  5. Antibiotics as low-molecular-mass displacers in ion-exchange displacement chromatography

    Microsoft Academic Search

    Amitava Kundu; Suresh Vunnum; Steven M. Cramer

    1995-01-01

    While the ability to carry out simultaneous concentration and purification in a single displacement step has significant advantages for downstream processing of pharmaceuticals, a major impediment to the implementtion of displacement chromatography has been the lack of suitable displacer compounds. An important recent advance in the state-of-the-art of displacement chromatography has been the discovery that low-molecular-mass dendritic polymers and protected

  6. Reliable Estimation of Dense Optical Flow Fields with Large Displacements

    Microsoft Academic Search

    Luis Alvarez; Joachim Weickert; Javier Sánchez

    2000-01-01

    In this paper we show that a classic optical flow technique by Nagel and Enkelmann (1986, IEEE Trans. Pattern Anal. Mach. Intell., Vol. 8, pp. 565–593) can be regarded as an early anisotropic diffusion method with a diffusion tensor. We introduce three improvements into the model formulation that (i) avoid inconsistencies caused by centering the brightness term and the smoothness

  7. A large displacement formulation for anisotropic beam analysis

    Microsoft Academic Search

    Marco Borri; Teodoro Merlini

    1986-01-01

    Sommario E' conveniente scomporre lo spostamento di un punto di una trave in una rototraslazione della sezione cui appartiene e in uno spostamento che deforma la sezione (in-gobbamento). Si deduce la corretta approssimazione al second'ordine della deformazione per grandi spostamenti e quindi grandi rotazioni. Vengono presentate sia la formulazione lineare che quella non lineare, basate sul metodo degli spostamenti: dalla

  8. Large-scale cortical displacement of a human retinotopic map

    E-print Network

    Slotnick, Scott D.

    with arteriovenous mal- formations (AVMs), a congenital abnormality, in either the foot or hand region of primary-Walker malformation. (b) Slice through ventral extrastriate visual areas.On this and the next slice, solid arrow

  9. Displacement thresholds in central and peripheral vision during tracking

    NASA Technical Reports Server (NTRS)

    Haines, R. F.

    1986-01-01

    The effects of stimulus duration and angular velocity on a subject's judgment of displacement threshold are examined. Twenty-six male subjects between 17-45 years with uncorrected 20:20 distance acuity and normal color perception and stereopsis studied a series of forced choice, paired comparison trials in which a long, thin, collimated horizontally oriented line moved downward through 12 angles ranging from 0.6-60 arcmin and judged which stimulus moved in each pair. The displacements were produced by 0.25, 0.5, 1, 2, and 4 sec stimulus duration and 2.5, 5, 10, and 15 deg/sec angular rates. Stimulus velocity, stimulus duration, mean threshold displacement, and mean confidence results are analyzed. It is observed that displacement judgment accuracy is increased with increasing stimulus duration. The data are compared with the results of Johnson and Leibowitz (1976) and Johnson and Scobey (1982), and good correlation with the Johnson and Leibowitz data is detected. The data reveal that threshold is based on a constant stimulus velocity over this range of durations and velocities. The data are applicable to the study of the final approach to landing of medium and large commercial jet aircraft.

  10. Optimization of legacy lidar data sets for measuring near-field earthquake displacements

    NASA Astrophysics Data System (ADS)

    Glennie, Craig L.; Hinojosa-Corona, Alejandro; Nissen, Edwin; Kusari, Arpan; Oskin, Michael E.; Arrowsmith, J. Ramon; Borsa, Adrian

    2014-05-01

    Airborne lidar (light detection and ranging) topography, acquired before and after an earthquake, can provide an estimate of the coseismic surface displacement field by differencing the preevent and postevent lidar point clouds. However, estimated displacements can be contaminated by the presence of large systematic errors in either of the point clouds. We present three-dimensional displacements obtained by differencing airborne lidar point clouds collected before and after the El Mayor-Cucapah earthquake, a Mw 7.2 earthquake that occurred in 2010. The original surface displacement estimates contained large, periodic artifacts caused by systematic errors in the preevent lidar data. Reprocessing the preevent data, detailed herein, removed a majority of these systematic errors that were largely due to misalignment between the scanning mirror and the outgoing laser beam. The methodology presented can be applied to other legacy airborne laser scanning data sets in order to improve change estimates from temporally spaced lidar acquisitions.

  11. Using a 2D displacement sensor to derive 3D displacement information

    NASA Technical Reports Server (NTRS)

    Soares, Schubert F. (Inventor)

    2002-01-01

    A 2D displacement sensor is used to measure displacement in three dimensions. For example, the sensor can be used in conjunction with a pulse-modulated or frequency-modulated laser beam to measure displacement caused by deformation of an antenna on which the sensor is mounted.

  12. Video Games, Adolescents, and the Displacement Effect

    ERIC Educational Resources Information Center

    Fisher, Carla Christine

    2012-01-01

    The displacement effect (the idea that time spent in one activity displaces time spent in other activities) was examined within the lens of adolescents' video game use and their time spent reading, doing homework, in physically active sports and activities, in creative play, and with parents and friends. Data were drawn from the Panel Study…

  13. Young Children's Understanding of Displaced Aggression.

    ERIC Educational Resources Information Center

    Weiss, Michael G.; Miller, Patricia H.

    1983-01-01

    Examines early phases of understanding of causes of moderately and extremely displaced aggression. Preschool and kindergarten children three to five years of age viewed eight videotaped episodes of displaced aggression. Comprehension was assessed by means of open-ended questions and forced-choice picture selections. (Author/RH)

  14. Displaced Homemakers: Vo-Tech Workshop Guide.

    ERIC Educational Resources Information Center

    Peltier, Wanda Jo

    Written for displaced homemaker programs in vocational-technical schools, this curriculum contains material designed so that instructors can prepare student manuals appropriate to almost any educational support situation for displaced homemakers. An overview provides information on special needs groups, curriculum use, and resources and sample…

  15. Atom-by-atom nucleation and growth of graphene nanopores

    PubMed Central

    Russo, Christopher J.; Golovchenko, J. A.

    2012-01-01

    Graphene is an ideal thin membrane substrate for creating molecule-scale devices. Here we demonstrate a scalable method for creating extremely small structures in graphene with atomic precision. It consists of inducing defect nucleation centers with energetic ions, followed by edge-selective electron recoil sputtering. As a first application, we create graphene nanopores with radii as small as 3 ?, which corresponds to 10 atoms removed. We observe carbon atom removal from the nanopore edge in situ using an aberration-corrected electron microscope, measure the cross-section for the process, and obtain a mean edge atom displacement energy of 14.1 ± 0.1 eV. This approach does not require focused beams and allows scalable production of single nanopores and arrays of monodisperse nanopores for atomic-scale selectively permeable membranes. PMID:22492975

  16. Ionization of low-Rydberg-state He atoms by polar molecules. II. Large rotational-energy transfers and absolute values of the cross sections

    Microsoft Academic Search

    A. Pesnelle; C. Ronge; M. Perdrix; G. Watel

    1988-01-01

    The absolute values of cross sections for the collisional ionization of low-Rydberg-state He atoms in the n 1P state (n=14) by the polar molecules NH3, SO2, and acetone (C3H6O) are measured in a crossed-beam experiment at thermal kinetic energies, for a well-defined relative velocity. Simultaneous Penning ionization of NH3 by metastable He(23S) atoms is carried out in situ for calibration.

  17. Feasibility study on ultrasonic lateral displacement measurement for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Matsuya, Iwao; Matsumoto, Fumiya; Ihara, Ikuo

    2014-02-01

    In structural health monitoring, measuring the relative lateral displacement of the structure is essential for direct damage detection. Although large numbers of studies have been made on the development of the range finder utilizing an optical sensor, little attention has been given to the measuring method for lateral displacement. We propose a novel measurement method for directly measuring the lateral displacement of the structures by means of the air-coupled ultrasound. The measurement system is composed of two flat-type air-coupled ultrasound transducers and a steel wire as a target. The ultrasound transducers are immobilized on a fixed point, whereas a steel wire is separately arranged on the opposite side. When the steel wire is displaced laterally to the ultrasound detectors, the lateral displacement is calculated by taking advantage of the intensity ratio of the reflected ultrasound waves. The accuracy of the lateral displacement measurement is experimentally assessed by conducting a laboratory test. The estimated displacement value in the far field region of the transducer agrees well with the reference. The result shows that the developed displacement measurement method will be useful for the health diagnosis of structures.

  18. Crustal displacements due to continental water loading

    USGS Publications Warehouse

    Van Dam, T.; Wahr, J.; Milly, P.C.D.; Shmakin, A.B.; Blewitt, G.; Lavallee, D.; Larson, K.M.

    2001-01-01

    The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (??rM) have root-mean-square (RMS) values for 1994-1998 as large as 8 mm, with ranges up to 30 mm, and are predominantly annual in character. Regional strains are on the order of 20 nanostrain for tilt and 5 nanostrain for horizontal deformation. We compare ??rM with observed Global Positioning System (GPS) heights (??rO) (which include adjustments to remove estimated effects of atmospheric pressure and annual tidal and non-tidal ocean loading) for 147 globally distributed sites. When the ??rO time series are adjusted by ??rM, their variances are reduced, on average, by an amount equal to the variance of the ??rM. Of the ??rO time series exhibiting a strong annual signal, more than half are found to have an annual harmonic that is in phase and of comparable amplitude with the annual harmonic in the ??rM. The ??rM time series exhibit long-period variations that could be mistaken for secular tectonic trends or post-glacial rebound when observed over a time span of a few years.

  19. Fault displacement hazard for strike-slip faults

    USGS Publications Warehouse

    Petersen, M.D.; Dawson, T.E.; Chen, R.; Cao, T.; Wills, C.J.; Schwartz, D.P.; Frankel, A.D.

    2011-01-01

    In this paper we present a methodology, data, and regression equations for calculating the fault rupture hazard at sites near steeply dipping, strike-slip faults. We collected and digitized on-fault and off-fault displacement data for 9 global strikeslip earthquakes ranging from moment magnitude M 6.5 to M 7.6 and supplemented these with displacements from 13 global earthquakes compiled byWesnousky (2008), who considers events up to M 7.9. Displacements on the primary fault fall off at the rupture ends and are often measured in meters, while displacements on secondary (offfault) or distributed faults may measure a few centimeters up to more than a meter and decay with distance from the rupture. Probability of earthquake rupture is less than 15% for cells 200 m??200 m and is less than 2% for 25 m??25 m cells at distances greater than 200mfrom the primary-fault rupture. Therefore, the hazard for off-fault ruptures is much lower than the hazard near the fault. Our data indicate that rupture displacements up to 35cm can be triggered on adjacent faults at distances out to 10kmor more from the primary-fault rupture. An example calculation shows that, for an active fault which has repeated large earthquakes every few hundred years, fault rupture hazard analysis should be an important consideration in the design of structures or lifelines that are located near the principal fault, within about 150 m of well-mapped active faults with a simple trace and within 300 m of faults with poorly defined or complex traces.

  20. Probing baryogenesis with displaced vertices at the LHC

    NASA Astrophysics Data System (ADS)

    Cui, Yanou; Shuve, Brian

    2015-02-01

    The generation of the asymmetric cosmic baryon abundance requires a departure from thermal equilibrium in the early universe. In a large class of baryogenesis models, the baryon asymmetry results from the out-of-equilibrium decay of a new, massive particle. We highlight that in the interesting scenario where this particle has a weak scale mass, this out-of-equilibrium condition requires a proper decay length larger than O(1) mm. Such new fields are within reach of the LHC, at which they can be pair produced leaving a distinctive, displaced-vertex signature. This scenario is realized in the recently proposed mechanism of baryogenesis where the baryon asymmetry is produced through the freeze-out and subsequent decay of a meta-stable weakly interacting massive particle ("WIMP baryogenesis"). In analogy to missing energy searches for WIMP dark matter, the LHC is an excellent probe of these new long-lived particles responsible for baryogenesis via the low-background displaced vertex channel. In our paper, we estimate the limits on simplified models inspired by WIMP baryogenesis from two of the most sensitive collider searches by CMS and ATLAS with 8 TeV LHC data. We also estimate the LHC reach at 13 TeV using current strategies, and demonstrate that up to a factor of 100 improvement in cross-section limits can be achieved by requiring two displaced vertices while lowering kinematic thresholds. For meta-stable WIMPs produced through electroweak interactions, the high luminosity LHC is sensitive to masses up to 2.5 TeV for lifetimes around 1 cm, while for singlets pair-produced through the off-shell-Higgs portal, the LHC is sensitive to production cross sections of O(10) ab for benchmark masses around 150 GeV. Our analysis and proposals also generally apply to displaced vertex signatures from other new physics such as hidden valley models, twin Higgs models and displaced supersymmetry.

  1. Efficiency Improvements to the Displacement Based Multilevel Structural Optimization Algorithm

    NASA Technical Reports Server (NTRS)

    Plunkett, C. L.; Striz, A. G.; Sobieszczanski-Sobieski, J.

    2001-01-01

    Multilevel Structural Optimization (MSO) continues to be an area of research interest in engineering optimization. In the present project, the weight optimization of beams and trusses using Displacement based Multilevel Structural Optimization (DMSO), a member of the MSO set of methodologies, is investigated. In the DMSO approach, the optimization task is subdivided into a single system and multiple subsystems level optimizations. The system level optimization minimizes the load unbalance resulting from the use of displacement functions to approximate the structural displacements. The function coefficients are then the design variables. Alternately, the system level optimization can be solved using the displacements themselves as design variables, as was shown in previous research. Both approaches ensure that the calculated loads match the applied loads. In the subsystems level, the weight of the structure is minimized using the element dimensions as design variables. The approach is expected to be very efficient for large structures, since parallel computing can be utilized in the different levels of the problem. In this paper, the method is applied to a one-dimensional beam and a large three-dimensional truss. The beam was tested to study possible simplifications to the system level optimization. In previous research, polynomials were used to approximate the global nodal displacements. The number of coefficients of the polynomials equally matched the number of degrees of freedom of the problem. Here it was desired to see if it is possible to only match a subset of the degrees of freedom in the system level. This would lead to a simplification of the system level, with a resulting increase in overall efficiency. However, the methods tested for this type of system level simplification did not yield positive results. The large truss was utilized to test further improvements in the efficiency of DMSO. In previous work, parallel processing was applied to the subsystems level, where the derivative verification feature of the optimizer NPSOL had been utilized in the optimizations. This resulted in large runtimes. In this paper, the optimizations were repeated without using the derivative verification, and the results are compared to those from the previous work. Also, the optimizations were run on both, a network of SUN workstations using the MPICH implementation of the Message Passing Interface (MPI) and on the faster Beowulf cluster at ICASE, NASA Langley Research Center, using the LAM implementation of UP]. The results on both systems were consistent and showed that it is not necessary to verify the derivatives and that this gives a large increase in efficiency of the DMSO algorithm.

  2. Atomicity in electronic commerce

    Microsoft Academic Search

    J. D. Tygar

    1996-01-01

    There is tremendous demand for the ability to be able to electronically buy and sell goods over networks. This field is called electronic commerce, and it has inspired a large variety of work. Unfortunately, much of that work ignores traditional transaction processing concerns — chiefly atomicity. This paper discusses the role of atomicity in electronic commerce. It then briefly surveys

  3. Displacement chromatography of isomers and therapeutic compounds.

    PubMed

    Qi, Yan; Huang, Junxiong

    2002-06-14

    Displacement chromatography was successfully used to separate a binary isomer mixture, epirubicin and doxorubicin, on Kromasil KR100-10 C18 250x4.6 mm I.D. (10 microm) column. Displacement parameters such as the types and the concentrations of displacer, the composition and the flow rate of the mobile phase were critically examined in this study. The displacer employed was 30 mg/ml benzethonium chloride. Loading of feed at lower initial organic level of mobile phase coupled with displacement at higher organic level was found to give efficient separation. A 30-mg amount of binary isomer mixture was separated on an analytical column. The purification of epirubicin from the closely related impurities present in raw product solution by displacement chromatography was also investigated. The purity of epirubicin required was greater than 99% with a recovery of 60%. The results have indicated that this process made good use of the high feed load, low solvent costs, and high resolution characteristics of displacement chromatography and offered the chromatographic engineer a powerful tool for the preparative purification of therapeutic compounds. PMID:12141564

  4. On the calculation of line strengths, oscillator strengths and lifetimes for very large principal quantum numbers in hydrogenic atoms and ions by the McLean-Watson formula

    NASA Astrophysics Data System (ADS)

    Hey, J. D.

    2014-08-01

    As a sequel to an earlier study (Hey 2009 J. Phys. B: At. Mol. Opt. Phys. 42 125701), we consider further the application of the line strength formula derived by Watson (2006 J. Phys. B: At. Mol. Opt. Phys. 39 L291) to transitions arising from states of very high principal quantum number in hydrogenic atoms and ions (Rydberg-Rydberg transitions, n > 1000). It is shown how apparent difficulties associated with the use of recurrence relations, derived (Hey 2006 J. Phys. B: At. Mol. Opt. Phys. 39 2641) by the ladder operator technique of Infeld and Hull (1951 Rev. Mod. Phys. 23 21), may be eliminated by a very simple numerical device, whereby this method may readily be applied up to n ? 10 000. Beyond this range, programming of the method may entail greater care and complexity. The use of the numerically efficient McLean-Watson formula for such cases is again illustrated by the determination of radiative lifetimes and comparison of present results with those from an asymptotic formula. The question of the influence on the results of the omission or inclusion of fine structure is considered by comparison with calculations based on the standard Condon-Shortley line strength formula. Interest in this work on the radial matrix elements for large n and n? is related to measurements of radio recombination lines from tenuous space plasmas, e.g. Stepkin et al (2007 Mon. Not. R. Astron. Soc. 374 852), Bell et al (2011 Astrophys. Space Sci. 333 377), to the calculation of electron impact broadening parameters for such spectra (Watson 2006 J. Phys. B: At. Mol. Opt. Phys. 39 1889) and comparison with other theoretical methods (Peach 2014 Adv. Space Res. in press), to the modelling of physical processes in H II regions (Roshi et al 2012 Astrophys. J. 749 49), and the evaluation bound-bound transitions from states of high n during primordial cosmological recombination (Grin and Hirata 2010 Phys. Rev. D 81 083005, Ali-Haïmoud and Hirata 2010 Phys. Rev. D 82 063521, Ali-Haïmoud 2013 Phys. Rev. D 87 023526).

  5. Atomic Physics

    NSDL National Science Digital Library

    Christopher Griffith

    This collection provides a basic introduction to Atomic Physics. It reviews the building blocks of atomic structure, explores atomic isotopes, explains Einstein's famous equation E = mc2, and introduces the various types of radiation.

  6. Disappearing charged tracks in association with displaced leptons from supersymmetry

    E-print Network

    Christoffer Petersson

    2014-11-03

    In this note we discuss a characteristic collider signature of models of gauge mediated supersymmetry breaking in which the selectron and smuon are mass-degenerate co-NLSP. In these models, all processes involving superpartners give rise to two NLSP selectrons or smuons, each of which subsequently decays to a nearly massless LSP gravitino and an electron or a muon. In a large region of the parameter space, the NLSPs travel macroscopic distances, of the order 0.1-1000 mm, before they decay. Hence, these models give rise to collider signatures involving charged tracks that end at vertices, which are inside the detector volume but displaced with respect to the original collision point, from which an electron or a muon is emitted. In order to probe this class of models we propose a search for disappearing charged tracks in association with displaced electrons or muons.

  7. Earthquake-induced soil displacements and their impact on rehabilitations

    PubMed Central

    KONAGAI, Kazuo

    2011-01-01

    A large earthquake can trigger long lasting geotechnical problems, which pose serious issues on both rehabilitations and land conservations. Therefore one of what required of us is to deduce as much hidden signs as possible from observable changes of landforms. Though serious, damage caused by the October 23rd 2004, Mid-Niigata Prefecture Earthquake has given us a rare opportunity to study the landform changes in mountainous terrain hit by this earthquake. An attempt was made to convert changes in elevation in Eulerian description for images obtained from remote-sensing technologies to Lagrangian displacements, because Lagrangian displacements can directly describe behaviors of soils, which are typically history-dependent. This paper documents some big pictures of earthquake-inflicted landform changes obtained through this attempt. PMID:21986310

  8. Atomic-Resolution STEM Imaging of Graphene at Low Voltage of 30 kV with Resolution Enhancement by Using Large Convergence Angle

    NASA Astrophysics Data System (ADS)

    Sawada, H.; Sasaki, T.; Hosokawa, F.; Suenaga, K.

    2015-04-01

    Atomic resolution at a low accelerating voltage with aberration correction is required to reduce the electron irradiation damage in scanning transmission electron microscopy imaging. However, the reduction in resolution caused by the diffraction limit becomes severe with increasing electron wavelength at low accelerating voltages. The developed aberration corrector can compensate for higher-order aberration in scanning transmission electron microscopy to expand the uniform phase angle. The resolution for imaging graphene at 30 kV is evaluated by changing the convergence angle for a probe-forming system with a higher-order aberration corrector. A single-carbon atom on graphene is successfully imaged at atomic resolution with a cold-field emission gun by dark-field imaging at an accelerating voltage of 30 kV.

  9. Atomic-Resolution STEM Imaging of Graphene at Low Voltage of 30 kV with Resolution Enhancement by Using Large Convergence Angle.

    PubMed

    Sawada, H; Sasaki, T; Hosokawa, F; Suenaga, K

    2015-04-24

    Atomic resolution at a low accelerating voltage with aberration correction is required to reduce the electron irradiation damage in scanning transmission electron microscopy imaging. However, the reduction in resolution caused by the diffraction limit becomes severe with increasing electron wavelength at low accelerating voltages. The developed aberration corrector can compensate for higher-order aberration in scanning transmission electron microscopy to expand the uniform phase angle. The resolution for imaging graphene at 30 kV is evaluated by changing the convergence angle for a probe-forming system with a higher-order aberration corrector. A single-carbon atom on graphene is successfully imaged at atomic resolution with a cold-field emission gun by dark-field imaging at an accelerating voltage of 30 kV. PMID:25955058

  10. 40 CFR 86.419-78 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...accordance with ASTM E 29-67. (2) For rotary engines, displacement means the maximum...

  11. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...reference in § 86.1). (2) For rotary engines, displacement means the maximum...

  12. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...reference in § 86.1). (2) For rotary engines, displacement means the maximum...

  13. 40 CFR 86.419-78 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...accordance with ASTM E 29-67. (2) For rotary engines, displacement means the maximum...

  14. 40 CFR 86.419-78 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...accordance with ASTM E 29-67. (2) For rotary engines, displacement means the maximum...

  15. 40 CFR 86.419-2006 - Engine displacement, motorcycle classes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...displacement, motorcycle classes. (a)(1) Engine displacement shall be calculated using nominal engine values and rounded to the nearest whole...reference in § 86.1). (2) For rotary engines, displacement means the maximum...

  16. Scale model studies of displacement ventilation

    E-print Network

    Okutan, Galip Mehmet

    1995-01-01

    Displacement ventilation is an air conditioning method that provides conditioned air to indoor environments with the goal to improve air quality while reducing energy consumption. This study investigates the performance ...

  17. Seismic transducer measures small horizontal displacements

    NASA Technical Reports Server (NTRS)

    Greenwood, T. L.

    1965-01-01

    Pendular seismic transducer mounted on base plate measures small horizontal displacements of structures subjected to vibration where no fixed reference point is available. Enclosure of transducer in transparent plastic case prevents air currents from disturbing the pendulum balance.

  18. Interferometer for measuring displacement and distance

    Microsoft Academic Search

    Toshihiro Kubota; Makoto Nara; Toshihiko Yoshino

    1987-01-01

    A simple interferometer for measuring both relative displacement and absolute distance is fabricated that uses a laser diode. The sign of the displacementis detected by means of a lambda\\/8 plate, and the distance is measured by an FM radar technique of modulating the laser-diode frequency. Measurement accuracies of 0.02 micron for displacement and 100 microns for distance are obtained over

  19. PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE

    NASA Technical Reports Server (NTRS)

    Wernet, M. P.

    1994-01-01

    Particle Imaging Velocimetry (PIV) is a quantitative velocity measurement technique for measuring instantaneous planar cross sections of a flow field. The technique offers very high precision (1%) directionally resolved velocity vector estimates, but its use has been limited by high equipment costs and complexity of operation. Particle Displacement Tracking (PDT) is an all-electronic PIV data acquisition and reduction procedure which is simple, fast, and easily implemented. The procedure uses a low power, continuous wave laser and a Charged Coupled Device (CCD) camera to electronically record the particle images. A frame grabber board in a PC is used for data acquisition and reduction processing. PDT eliminates the need for photographic processing, system costs are moderately low, and reduced data are available within seconds of acquisition. The technique results in velocity estimate accuracies on the order of 5%. The software is fully menu-driven from the acquisition to the reduction and analysis of the data. Options are available to acquire a single image or 5- or 25-field series of images separated in time by multiples of 1/60 second. The user may process each image, specifying its boundaries to remove unwanted glare from the periphery and adjusting its background level to clearly resolve the particle images. Data reduction routines determine the particle image centroids and create time history files. PDT then identifies the velocity vectors which describe the particle movement in the flow field. Graphical data analysis routines are included which allow the user to graph the time history files and display the velocity vector maps, interpolated velocity vector grids, iso-velocity vector contours, and flow streamlines. The PDT data processing software is written in FORTRAN 77 and the data acquisition routine is written in C-Language for 80386-based IBM PC compatibles running MS-DOS v3.0 or higher. Machine requirements include 4 MB RAM (3 MB Extended), a single or multiple frequency RGB monitor (EGA or better), a math co-processor, and a pointing device. The printers supported by the graphical analysis routines are the HP Laserjet+, Series II, and Series III with at least 1.5 MB memory. The data acquisition routines require the EPIX 4-MEG video board and optional 12.5MHz oscillator, and associated EPIX software. Data can be acquired from any CCD or RS-170 compatible video camera with pixel resolution of 600hX400v or better. PDT is distributed on one 5.25 inch 360K MS-DOS format diskette. Due to the use of required proprietary software, executable code is not provided on the distribution media. Compiling the source code requires the Microsoft C v5.1 compiler, Microsoft QuickC v2.0, the Microsoft Mouse Library, EPIX Image Processing Libraries, the Microway NDP-Fortran-386 v2.1 compiler, and the Media Cybernetics HALO Professional Graphics Kernal System. Due to the complexities of the machine requirements, COSMIC strongly recommends the purchase and review of the documentation prior to the purchase of the program. The source code, and sample input and output files are provided in PKZIP format; the PKUNZIP utility is included. PDT was developed in 1990. All trade names used are the property of their respective corporate owners.

  20. Displacement sensor for indoor machine calibrations.

    PubMed

    Mudassar, Asloob Ahmad; Butt, Saira

    2013-05-20

    This paper presents a simple displacement sensor for indoor machine calibrations. The sensor, which is placed in the path of a diverging laser beam, consists of two plane mirror pieces laterally displaced with the line joining their centers initially held perpendicular to the optical axis of the beam during the displacement of the sensor with one of the mirrors always traveling along the optical axis of the laser beam. The optical signals from the two mirrors are combined and a simple detector at the interference plane counts the fringes during the sensor displacement. The sensor could be mounted on the moving head of any mechanical machine, e.g., the lathe machine for displacement calibration. The device has been tested over a range of 10 cm beyond a distance of 150 cm from a diverging laser source giving an accuracy of 1.1015 ?m. Theoretical modeling, simulation, and experimental results are presented which establish that the proposed sensor can be used as a promising displacement measuring device. PMID:23736230

  1. cif core.dic 1 ATOM SITE Dictionary name: cif core.dic

    E-print Network

    Meagher, Mary

    cif core.dic 1 ATOM SITE Dictionary name: cif core.dic Dictionary version: 2.2 Dictionary last updated: 2001-01-11 ØÓÑ × Ø Data items in the ATOM SITE category record details about the atom sites in a crystal structure, such as the positional coordinates, atomic displacement parameters, magnetic mo- ments

  2. Atomic Structure

    NSDL National Science Digital Library

    The Concord Consortium

    2011-12-11

    In this activity students explore the structure and properties of atoms. They construct models of atoms with properties of particular mass and charge; create models of atoms with different stabilities by adding or subtracting neutrons, protons, and electrons to a model atom; and determine that the same element may have varying number of neutrons and these form isotopes.Students will be able to:

  3. Atom Chips

    E-print Network

    Ron Folman; Peter Krüger; Donatella Cassettari; Björn Hessmo; Thomas Maier; Jörg Schmiedmayer

    1999-12-23

    Atoms can be trapped and guided using nano-fabricated wires on surfaces, achieving the scales required by quantum information proposals. These Atom Chips form the basis for robust and widespread applications of cold atoms ranging from atom optics to fundamental questions in mesoscopic physics, and possibly quantum information systems.

  4. Autonomous dynamic displacement estimation from data fusion of acceleration and intermittent displacement measurements

    NASA Astrophysics Data System (ADS)

    Kim, Junhee; Kim, Kiyoung; Sohn, Hoon

    2014-01-01

    Addressing the importance of displacement measurement of structural responses in the field of structural health monitoring, this paper presents an autonomous algorithm for dynamic displacement estimation from acceleration integration fused with displacement data intermittently measured. The presented acceleration integration algorithm of multi-rate Kalman filtering distinguishes itself from the past study in the literature by explicitly considering acceleration measurement bias. Furthermore, the algorithm is formulated by unique state definition of integration errors and error dynamics system modeling. To showcase performance of the algorithm, a series of laboratory dynamic experiments for measuring structural responses of acceleration and displacement are conducted. Improved results are demonstrated through comparison between the proposed and past study.

  5. Atom Interferometers

    E-print Network

    Alexander D. Cronin; Joerg Schmiedmayer; David E. Pritchard

    2007-12-21

    Interference with atomic and molecular matter waves is a rich branch of atomic physics and quantum optics. It started with atom diffraction from crystal surfaces and the separated oscillatory fields technique used in atomic clocks. Atom interferometry is now reaching maturity as a powerful art with many applications in modern science. In this review we first describe the basic tools for coherent atom optics including diffraction by nanostructures and laser light, three-grating interferometers, and double wells on AtomChips. Then we review scientific advances in a broad range of fields that have resulted from the application of atom interferometers. These are grouped in three categories: (1) fundamental quantum science, (2) precision metrology and (3) atomic and molecular physics. Although some experiments with Bose Einstein condensates are included, the focus of the review is on linear matter wave optics, i.e. phenomena where each single atom interferes with itself.

  6. Two-dimensional simulations of displacement accumulation incorporating shear strain

    PubMed Central

    Bayer, Matthew; Hall, Timothy J.; Neves, Lucio P.; Carneiro, A. A. O.

    2015-01-01

    Using ultrasound images to track large tissue deformations usually requires breaking up the deformation into steps and then summing the resulting displacement estimates. The accumulated displacement estimation error therefore depends on the error in each step, but also on the statistical relationships between estimation steps. These relationships have not been thoroughly studied. Building on previous work with one-dimensional simulations, the work reported here measured error variance for single-step and accumulated displacement estimates using two-dimensional numerical simulations of ultrasound echo signals, subjected to both normal and axial shear strain as well as electronic noise. Previous results were confirmed, showing that errors due to electronic noise are negatively correlated between steps and accumulate slowly, while errors due to strain are positively correlated and accumulate quickly. These properties hold for both normal and axial shear strain. A general comparison of tracking performance for tissue under normal and axial shear strain was also performed. Under axial shear strain error variance tends to increase with larger lateral kernel sizes but decrease for larger axial kernel sizes; the opposite relationship holds under normal strain. A combination of these two types of strain limits the practical kernel size in both dimensions. PMID:24275539

  7. Measurement of a Large Chemical Reaction Rate between Ultracold Closed-Shell {sup 40}Ca Atoms and Open-Shell {sup 174}Yb{sup +} Ions Held in a Hybrid Atom-Ion Trap

    SciTech Connect

    Rellergert, Wade G.; Sullivan, Scott T.; Chen Kuang; Schowalter, Steven J.; Hudson, Eric R. [Department of Physics and Astronomy, University of California, Los Angeles, California 90095 (United States); Kotochigova, Svetlana; Petrov, Alexander [Department of Physics, Temple University, Philadelphia, Pennsylvania 19122 (United States)

    2011-12-09

    Ultracold {sup 174}Yb{sup +} ions and {sup 40}Ca atoms are confined in a hybrid trap. The charge exchange chemical reaction rate constant between these two species is measured and found to be 4 orders of magnitude larger than recent measurements in other heteronuclear systems. The structure of the CaYb{sup +} molecule is determined and used in a calculation that explains the fast chemical reaction as a consequence of strong radiative charge transfer. A possible explanation is offered for the apparent contradiction between typical theoretical predictions and measurements of the radiative association process in this and other recent experiments.

  8. Do you believe that atoms stay in place when you observe them in HREM?

    PubMed

    Van Dyck, Dirk; Lobato, Ivan; Chen, Fu-Rong; Kisielowski, Christian

    2015-01-01

    Recent advancements in aberration-corrected electron microscopy allow for an evaluation of unexpectedly large atom displacements beyond a resolution limit of ?0.5 Å, which are found to be dose-rate dependent in high resolution images. In this paper we outline a consistent description of the electron scattering process, which explains these unexpected phenomena. Our approach links thermal diffuse scattering to electron beam-induced object excitation and relaxation processes, which strongly contribute to the image formation process. The effect can provide an explanation for the well-known contrast mismatch ("Stobbs factor") between image calculations and experiments. PMID:25311646

  9. Gas miscible displacement enhanced oil recovery: Technology status report

    SciTech Connect

    Not Available

    1986-10-01

    Gas miscible displacement enhanced oil recovery research is conducted by the US Department of Energy's Morgantown Energy Technology Center to advance the application of miscible carbon dioxide flooding. This research is an integral part of a multidisciplinary effort to improve the technology for producing additional oil from US resources. This report summarizes the problems of the technology and the 1986 results of the ongoing research that was conducted to solve those problems. Poor reservoir volumetric sweep efficiency is the major problem associated with gas flooding and all miscible displacements. This problem results from the channeling and viscous fingering that occur due to the large differences between viscosity or density of the displacing and displaced fluids (i.e., carbon dioxide and oil, respectively). Simple modeling and core flooding studies indicate that, because of differences in fluid viscosities, breakthrough can occur after only 30% of the total pore volume (PV) of the rock has been injected with gas, while field tests have shown breakthrough occurring much earlier. The differences in fluid densities lead to gravity segregation. The lower density carbon dioxide tends to override the residual fluids in the reservoir. This process would be considerably more efficient if a larger area of the reservoir could be contacted by the gas. Current research has focused on the mobility control, computer simulation, and reservoir heterogeneity studies. Three mobility control methods have been investigated: (1) the use of polymers for direct thickening of high-density carbon dioxide, (2) mobile ''foam-like dispersions'' of carbon dioxide and an aqueous surfactant, and (3) in situ deposition of chemical precipitates. 22 refs., 14 figs., 6 tabs.

  10. Defect cluster formation in displacement cascades in copper

    NASA Astrophysics Data System (ADS)

    Osetsky, Yu. N.; Bacon, D. J.

    2001-06-01

    Extensive study of primary damage in displacement cascades in metals by computer simulation has shown that the total number of defects produced is significantly lower than predicted by the Norgett, Robinson and Torrens (NRT) model and that a significant fraction of the self-interstitials forms glissile clusters. However, there is a lack of variety of defect types observed in cascade simulation, which, in many cases, makes it difficult to explain experimental data. For example, experiments on copper show efficient production of stacking fault tetrahedra (SFTs) but they were not observed systematically in computer simulation. To consider this further, extensive simulation of displacement cascades in copper has been performed using two different interatomic potentials, a short-range many-body potential (MBP) and a long-range pair potential (PP). Primary knock-on-atom (PKA) energy in the range 2-20 keV and temperatures of 100 and 600 K were considered. Special attention was paid to cascade statistics and the accuracy of simulation in the collision stage. The former required many simulations for each energy whereas the latter involved a modification of the simulation method to treat a hot region with high accuracy by applying a smaller time step. Results showing the variety of clusters observed, e.g. SFTs, glissile and sessile interstitial clusters, and faulted and perfect interstitial dislocation loops, are presented.

  11. Molecular dynamics simulation of low energy displacement cascades in Cu

    NASA Astrophysics Data System (ADS)

    King, Wayne E.; Benedek, R.

    1983-07-01

    Molecular dynamics computer simulations have been performed to study properties of low-energy (< 500 eV) displacement cascades in Cu. Various aspects of the time development of cascades are considered including instantaneous number of Frenkel pairs, partitioning of kinetic and potential energies, distribution of atom kinetic energies, cascade expansion rate, and Frenkel pair distributions. The anisotropy of the threshold energy for Frenkel-pair production is interpreted in terms of "branching". Replacement sequences and the damage function are discussed based on analysis of events corresponding to 18 recoil directions. The damage function exhibits a plateau at v ~ 0.5 Frenkel pairs extending from 25-150 eV; at higher recoil energies the onset of multiple defect production is much slower than predicted by the modified Kinchin-Pease model.

  12. Wavelet denoising of displacement estimates in elastography.

    PubMed

    Techavipoo, Udomchai; Varghese, Tomy

    2004-04-01

    Wavelet shrinkage denoising of the displacement estimates to reduce noise artefacts, especially at high overlaps in elastography, is presented in this paper. Correlated errors in the displacement estimates increase dramatically with an increase in the overlap between the data segments. These increased correlated errors (due to the increased correlation or similarity between consecutive displacement estimates) generate the so-called "worm" artefact in elastography. However, increases in overlap on the order of 90% or higher are essential to improve axial resolution in elastography. The use of wavelet denoising significantly reduces errors in the displacement estimates, thereby reducing the worm artefacts, without compromising on edge (high-frequency or detail) information in the elastogram. Wavelet denoising is a term used to characterize noise rejection by thresholding the wavelet coefficients. Worm artefacts can also be reduced using a low-pass filter; however, low-pass filtering of the displacement estimates does not preserve local information such as abrupt change in slopes, causing the smoothing of edges in the elastograms. Simulation results using the analytic 2-D model of a single inclusion phantom illustrate that wavelet denoising produces elastograms with the closest correspondence to the ideal mechanical strain image. Wavelet denoising applied to experimental data obtained from an in vitro thermal lesion phantom generated using radiofrequency (RF) ablation also illustrates the improvement in the elastogram noise characteristics. PMID:15121250

  13. Ultra-Sensitive Magnetoresistive Displacement Sensing Device

    NASA Technical Reports Server (NTRS)

    Olivas, John D. (Inventor); Lairson, Bruce M. (Inventor); Ramesham, Rajeshuni (Inventor)

    2003-01-01

    An ultrasensitive displacement sensing device for use in accelerometers, pressure gauges, temperature transducers, and the like, comprises a sputter deposited, multilayer, magnetoresistive field sensor with a variable electrical resistance based on an imposed magnetic field. The device detects displacement by sensing changes in the local magnetic field about the magnetoresistive field sensor caused by the displacement of a hard magnetic film on a movable microstructure. The microstructure, which may be a cantilever, membrane, bridge, or other microelement, moves under the influence of an acceleration a known displacement predicted by the configuration and materials selected, and the resulting change in the electrical resistance of the MR sensor can be used to calculate the displacement. Using a micromachining approach, very thin silicon and silicon nitride membranes are fabricated in one preferred embodiment by means of anisotropic etching of silicon wafers. Other approaches include reactive ion etching of silicon on insulator (SOI), or Low Pressure Chemical Vapor Deposition of silicon nitride films over silicon substrates. The device is found to be improved with the use of giant magnetoresistive elements to detect changes in the local magnetic field.

  14. Inefficiency of upward displacement operating theatre ventilation.

    PubMed

    Friberg, B; Friberg, S; Burman, L G; Lundholm, R; Ostensson, R

    1996-08-01

    A new thermally based ventilation system ('Floormaster') with inlet of cool clean air at floor level, and evacuation at the ceiling of the air warmed by activity in the room (upward displacement ventilation, 17 air changes/h) was compared with a standard positive pressure (plenum) ventilation system with air supply through an inclined perforated screen along one wall at the ceiling and evacuation at floor level (conventional turbulent or mixing system, 16 air changes/h). The study was made during rigidly standardized sham operations (N = 20) performed in the same operating room by a six-member team wearing non-woven disposable or cotton clothing. In general the upward displacement system removed dust particles too small to carry bacteria (0.16-<0.3 microm, 0.001displacement system also yielded two to threefold higher air and surface bacterial counts in areas important for surgical asepsis (wound area, instrument table) especially with regard to bacterial sedimentation (0.001displacement system was insufficient elimination of the larger bacteria-carrying particles. The type of clothing worn by the members of the team did not influence the overall results. We conclude that an upward displacement system will lead to increased counts of airborne and sedimenting bacteria and thus increase the risk of postoperative infection in comparison with conventional operating room ventilation systems. PMID:8999051

  15. Implementation of 3D spatial indexing and compression in a large-scale molecular dynamics simulation database for rapid atomic contact detection

    PubMed Central

    2011-01-01

    Background Molecular dynamics (MD) simulations offer the ability to observe the dynamics and interactions of both whole macromolecules and individual atoms as a function of time. Taken in context with experimental data, atomic interactions from simulation provide insight into the mechanics of protein folding, dynamics, and function. The calculation of atomic interactions or contacts from an MD trajectory is computationally demanding and the work required grows exponentially with the size of the simulation system. We describe the implementation of a spatial indexing algorithm in our multi-terabyte MD simulation database that significantly reduces the run-time required for discovery of contacts. The approach is applied to the Dynameomics project data. Spatial indexing, also known as spatial hashing, is a method that divides the simulation space into regular sized bins and attributes an index to each bin. Since, the calculation of contacts is widely employed in the simulation field, we also use this as the basis for testing compression of data tables. We investigate the effects of compression of the trajectory coordinate tables with different options of data and index compression within MS SQL SERVER 2008. Results Our implementation of spatial indexing speeds up the calculation of contacts over a 1 nanosecond (ns) simulation window by between 14% and 90% (i.e., 1.2 and 10.3 times faster). For a 'full' simulation trajectory (51 ns) spatial indexing reduces the calculation run-time between 31 and 81% (between 1.4 and 5.3 times faster). Compression resulted in reduced table sizes but resulted in no significant difference in the total execution time for neighbour discovery. The greatest compression (~36%) was achieved using page level compression on both the data and indexes. Conclusions The spatial indexing scheme significantly decreases the time taken to calculate atomic contacts and could be applied to other multidimensional neighbor discovery problems. The speed up enables on-the-fly calculation and visualization of contacts and rapid cross simulation analysis for knowledge discovery. Using page compression for the atomic coordinate tables and indexes saves ~36% of disk space without any significant decrease in calculation time and should be considered for other non-transactional databases in MS SQL SERVER 2008. PMID:21831299

  16. Application of dynamic displacement current for diagnostics of subnanosecond breakdowns in an inhomogeneous electric field

    SciTech Connect

    Shao Tao; Zhang Cheng; Yan Ping [Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing 100190 (China); Key Laboratory of Power Electronics and Electric Drive, Chinese Academy of Sciences, Beijing 100190 (China); Tarasenko, Victor F.; Burachenko, Alexandr G.; Rybka, Dmitry V.; Kostyrya, Igor' D.; Lomaev, Mikhail I.; Baksht, Evgeni Kh. [Institute of High Current Electronics, Russian Academy of Sciences, Tomsk 634055 (Russian Federation)

    2013-05-15

    The breakdown of different air gaps at high overvoltages in an inhomogeneous electric field was investigated with a time resolution of up to 100 ps. Dynamic displacement current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a supershort avalanche electron beam (SAEB) with amplitudes of {approx}10 A and more, conductivity in the air gaps at the breakdown stage is ensured by the ionization wave, whose front propagates from the electrode of small curvature radius, and by the dynamic displacement current between the ionization wave front and the plane electrode. The amplitude of the dynamic displacement current measured by a current shunt is 100 times greater than the SAEB. It is shown that with small gaps and with a large cathode diameter, the amplitude of the dynamic displacement current during a subnanosecond rise time of applied pulse voltage can be higher than 4 kA.

  17. Rhetorics of Displacement: Constructing Identities in Forced Relocations

    ERIC Educational Resources Information Center

    Powell, Katrina M.

    2012-01-01

    Forced displacement has often involved the use of rhetoric, both by government institutions and by people who struggle not only to survive displacement, but also to resist it. In this article, the author offers first a theoretical framework that informs her thinking about displacement narratives. She briefly examines two published displacement

  18. Traumatic testicular displacement in motorcycle drivers.

    PubMed

    Je?menica, Dragan S; Alempijevi?, Djordje M; Pavleki?, Snežana; Aleksandri?, Branimir V

    2011-03-01

    Testicular displacement is a rare clinical presentation of blunt scrotal injury that may take place in road traffic accidents involving motorcycle occupants. We are presenting two cases of motorcycle occupant fatalities, 21 and 24 years of age, where testicular displacement and other signs of groin trauma have been determined. In both cases, discrete external signs of scrotal trauma were noted on examination, while unilateral and bilateral traumatic testicular displacement, respectively, have been documented at autopsy. For motorcycle occupants involved in collision, it is necessary to perform a thorough analysis of injuries, in particular to look for specific trauma arising from fuel-tank impact to genitalia and/or groin. These injuries are of great medico-legal importance both at postmortem and in clinical cases involving motorcycle occupants involved in collision. PMID:21306375

  19. Joint estimation of real squeezing and displacement

    E-print Network

    G. Chiribella; G. M. D'Ariano; M. F. Sacchi

    2006-01-18

    We study the problem of joint estimation of real squeezing and amplitude of the radiation field, deriving the measurement that maximizes the probability density of detecting the true value of the unknown parameters. More generally, we provide a solution for the problem of estimating the unknown unitary action of a nonunimodular group in the maximum likelihood approach. Remarkably, in this case the optimal measurements do not coincide with the so called square-root measurements. In the case of squeezing and displacement we analyze in detail the sensitivity of estimation for coherent states and displaced squeezed states, deriving the asymptotic relation between the uncertainties in the joint estimation and the corresponding uncertainties in the optimal separate measurements of squeezing and displacement. A two-mode setup is also analyzed, showing how entanglement between optical modes can be used to approximate perfect estimation.

  20. Displacement sensors using soft magnetostrictive alloys

    SciTech Connect

    Hristoforou, E. (NCSR Demokritos Aghia Paraskevi, Athens (Greece). Inst. of Material Science); Reilly, R.E. (King's College London (United Kingdom). Electronic and Electrical Engineering Dept.)

    1994-09-01

    The authors report results on the response of a family of displacement sensors, which are based on the magnetostrictive delay line (MDL) technique, using current conductor orthogonal to the MDL. Such sensing technique is based on the change of the magnetic circuit and the acoustic stress point of origin due to the displacement of a soft magnetic material above it. Integrated arrays of sensors can be obtained due to the acoustic delay line technique and they can be used as tactile arrays, digitizers or devices for medical application (gait analysis etc.), while absence of hysteresis and low cost of manufacturing make them competent in this sector of sensor market.

  1. Icosahedral quasicrystals of intermetallic compounds are icosahedral twins of cubic crystals of three kinds, consisting of large (about 5000 atoms) icosahedral complexes in either a cubic body-centered or a cubic face-centered arrangement or smaller (about 1350 atoms) icosahedral complexes in the ?-tungsten arrangement

    PubMed Central

    Pauling, Linus

    1989-01-01

    The twofold-axis electron-diffraction photographs of icosahedral quasicrystals are of three kinds, reflecting three different structures of the cubic crystals that by icosahedral twinning form the quasicrystals. The first kind, represented by Al13Cu4Fe3, contains two very large icosahedral complexes, each of about 4680 atoms, in the body-centered arrangement, with six smaller icosahedral complexes (104 atoms each) in the principal interstices. The second kind, represented by Al5Mn, contains four of the very large complexes in the face-centered arrangement (cubic close packing), with four of the smaller clusters in the interstices. The third kind, represented by Al6CuLi3, contains eight icosahedral complexes, each of about 1350 atoms, in the ?-W arrangement. The supporting evidence for these cubic structures is discussed as well as other evidence showing that the simple quasicrystal theory, which states that quasicrystals do not involve any translational identity operations, has to be modified. Images PMID:16594078

  2. The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks

    PubMed Central

    Müller, Corsin A.; Riemer, Stefanie; Range, Friederike; Huber, Ludwig

    2014-01-01

    Visible and invisible displacement tasks have been used widely for comparative studies of animals’ understanding of object permanence, with evidence accumulating that some species can solve invisible displacement tasks and thus reach Piagetian stage 6 of object permanence. In contrast, dogs appear to rely on associative cues, such as the location of the displacement device, during invisible displacement tasks. It remains unclear, however, whether dogs, and other species that failed in invisible displacement tasks, do so due to their inability to form a mental representation of the target object, or simply due to the involvement of a more salient but potentially misleading associative cue, the displacement device. Here we show that the use of a displacement device impairs the performance of dogs also in visible displacement tasks: their search accuracy was significantly lower when a visible displacement was performed with a displacement device, and only two of initially 42 dogs passed the sham-baiting control conditions. The negative influence of the displacement device in visible displacement tasks may be explained by strong associative cues overriding explicit information about the target object’s location, reminiscent of an overshadowing effect, and/or object individuation errors as the target object is placed within the displacement device and moves along a spatiotemporally identical trajectory. Our data suggest that a comprehensive appraisal of a species’ performance in object permanence tasks should include visible displacement tasks with the same displacement device used in invisible displacements, which typically has not been done in the past. PMID:24611641

  3. Comment on "Measurement of a large Chemical Reaction Rate between Ultracold Closed-Shell ^{40}Ca Atoms and Open-Shell ^{174}Yb^{+} Ions Held in a Hybrid Atom-Ion Trap"

    E-print Network

    Zygelman, B

    2012-01-01

    We estimate the radiative quenching rate of the $^{40}$Ca - $^{174}$Yb$^{+}$ molecular ion and find that it under-estimates the value reported in recent experiments by about 5 orders of magnitude. We comment on possible explanations for this large discrepancy.

  4. MODERN RESONANT X-RAY STUDIES OF ALLOYS: Local Order and Displacements1

    NASA Astrophysics Data System (ADS)

    Ice, G. E.; Sparks, C. J.

    1999-08-01

    The recent availability of intense synchrotron sources with selectable X-ray energies permits high-precision measurements of chemically specific atomic-pair correlations in solid-solution alloys. Short-range chemical order can be accurately measured to identify one atom in a 100 for 10 or more shells, even in alloys with elements nearby in the periodic table, and chemically specific static displacements can be measured with 0.0001 nm resolution. This new information tests theoretical models of alloy phase stability and structure and gives new insights into the physical properties of alloys.

  5. Nonlinear contact resonance spectroscopy in atomic force microscopy

    Microsoft Academic Search

    Daniel Rupp; Ute Rabe; Sigrun Hirsekorn; Walter Arnold

    2007-01-01

    There are several techniques which combine atomic force microscopy with ultrasonics. In atomic force acoustic microscopy the cantilever is forced to ultrasonic vibrations while the tip is in contact with a sample surface. The various physical forces acting between the tip and the surface depend nonlinearly on the distance. Therefore linear approximations are restricted to tip-sample displacements covering small parts

  6. SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS - EXPERIMENTAL STUDIES

    Microsoft Academic Search

    Michael B. Rannow; Haink C. Tu; Perry Y. Li; Thomas R. Chase

    2006-01-01

    The majority of hydraulic systems are controlled using a me- tering valve or the use of variable displacement pumps. Metering valve control is compact and has a high control bandwidth, but it is energy inefficient due to throttling losses. Variable d isplace- ment pumps are far more efficient as the pump only produces the required flow, but comes with the

  7. RECOVERY OF METALS USING ALUMINUM DISPLACEMENT

    EPA Science Inventory

    The removal of typical metals (Cu, Pb, Sn, Ni) from printed circuit and metal finishing waste streams was evaluated using displacement with aluminum. he metal is recovered as non-hazardous metal particles and can be recycled by smelting. n acceptable aluminum metal configuration ...

  8. RECOVERY OF METAL USING ALUMINUM DISPLACEMENT

    EPA Science Inventory

    The removal of typical metals (Cu, Pb, Sn, Ni) from printed circuit and metal finishing waste streams was evaluated using displacement with aluminum. he metal is recovered as non-hazardous metal particles and can be recycled by smelting. n acceptable aluminum metal configuration ...

  9. Dissociation and Displacement: Where Goes the “Ouch?”

    Microsoft Academic Search

    John G. Watkins; Helen H. Watkins

    1990-01-01

    Hypnosis is widely used to relieve pain. Current theory emphasizes its dissociative features. Multiple personality patients can eliminate pain in the primary personality by displacing it into underlying alters. The Hilgards demonstrated that normal hypnotized subjects can similarly dissociate pain into a covert cognitive structural system which they called the “hidden observer.” The Watkins discovered that “hidden observers” appeared to

  10. Coreflood experimental study of steam displacement

    E-print Network

    Cerutti, Andres Enrique

    1997-01-01

    The main objective of this study was to verify experimentally whether or not a Buckley-Leverett shock front exists when steam displaces oil in a porous medium, as assumed in the Aydelotte-Pope steamflood predictive model. Experiments were conducted...

  11. Phase displacement acceleration in the SSC

    SciTech Connect

    Hofmann, A.

    1984-08-01

    The SSC (Superconducting Super Collider) is supposed to operate with bunched beams and the energy radiated by synchrotron radiation is replaced by the rf-system having a synchronous phase angle slightly different from 180/sup 0/. Here the case of operating the SSC with a coasting beam is considered. In particular the possibility of replacing the radiated energy phase displacement acceleration is investigated.

  12. Embedded fiber optic beam displacement sensor

    Microsoft Academic Search

    Roger M. Crane; Eugene C. Fischer

    1991-01-01

    This document discloses a method and apparatus for the two dimensional measurement of displacements of sample materials using a photodetector grid array and optical fiber embedded in the test specimen. The system consists of a light source which is passed into one end of an optical fiber which has embedded a beam specimen, so that when the beam is placed

  13. Acoustic shear wave displacement measurement using ultrasound

    Microsoft Academic Search

    Vinayak Dutt; Randall R. Kinnick; James F. Greenleaf

    1996-01-01

    Echo ultrasound can be used to detect and measure acoustic shear waves. Earlier it has been shown that a phase contrast based magnetic resonance imaging technique can be used for cyclic shear wave displacement measurement. Echo ultrasound presents an alternate method for imaging of such shear waves. The ultrasound based method uses the phase of quadrature echo signals to estimate

  14. Variable-Displacement Hydraulic Drive Unit

    NASA Technical Reports Server (NTRS)

    Lang, D. J.; Linton, D. J.; Markunas, A.

    1986-01-01

    Hydraulic power controlled through multiple feedback loops. In hydraulic drive unit, power closely matched to demand, thereby saving energy. Hydraulic flow to and from motor adjusted by motor-control valve connected to wobbler. Wobbler angle determines motor-control-valve position, which in turn determines motor displacement. Concept applicable to machine tools, aircraft controls, and marine controls.

  15. Extracting gravity line displacement from stabilographic recordings

    Microsoft Academic Search

    Deborah L. King; Vladimir M. Zatsiorsky

    1997-01-01

    Three algorithms for determining gravity line (GL) location from center of pressure (COP) and horizontal force (Fx) recordings are suggested. The algorithms are designed to study upright standing posture and are based on the following premises: (a) the foot(feet) is a solid body and does not move, (b) the axis of rotation of the ankle joint does not displace, and

  16. Retraining Displaced Workers--Barriers and Facilitators.

    ERIC Educational Resources Information Center

    Wolansky, William D.

    Although plant closings and layoffs have been happening for a long time, today's recessions, major changes in the structure of the economy, and a tight job market have combined to make plant closings a more serious problem. Workers are faced with unemployment from both traditional labor-displacing changes, such as the increasing use of robotics;…

  17. Job Displacement and the Rural Worker.

    ERIC Educational Resources Information Center

    Podgursky, Michael

    High rates of unemployment in rural areas poses questions as what education can do with the problem. This report examines the effects of rural American economies as they grow away from agriculture and toward dependence on manufacturing and service industries. Using data from the federal Bureau of Labor Statistics' Displaced Worker Survey, the…

  18. A Personal Appearance Program for Displaced Homemakers.

    ERIC Educational Resources Information Center

    Fiore, Ann Marie; De Long, Marilyn Revell

    1990-01-01

    A career counseling program evaluated the self-esteem of 28 displaced homemakers, then presented 3 sessions on the importance of personal appearance in hiring practices, wardrobe management, nonverbal communication, professional image, and self-concept. Analysis of participant evaluations indicated improved levels of control and confidence and…

  19. Careers for Homemakers (A Displaced Homemakers Program).

    ERIC Educational Resources Information Center

    Hanks, Marlene

    St. Louis Community College's Careers for Homemakers program is a vocational counseling program designed to help displaced homemakers enter the job market for the first time or after a significant absence. The program's goal is to place participants, chosen according to academic or economic disadvantaged eligibility, in jobs consistent with their…

  20. Atom interferometers and atom holography

    SciTech Connect

    Shimizu, Fujio; Mitake, Satoru [Institute for Laser Science and CREST, University of Electro-Communications, Chofu-shi 182-8585 (Japan); Fujita, Jun-ichi [NEC Fundamental Research Laboratories, 34 Miyukigaoka, Tsukuba 305-0841 (Japan); Morinaga, Makoto [Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan); Kishimoto, Tetsuo [Institute for Laser Science and CREST, University of Electro-Communications, Chofu-shi 182-8585 (Japan); Department of Applied Physics, University of Tokyo, Bunkyo-ku, Tokyo 113 (Japan)

    1999-06-11

    Various techniques of atom manipulation with a binary hologram are discussed and demonstrated experimentally. An atomic beam of metastable neon in the 1s{sub 3} state and a SiN thin film with holes that expresses the transmission function of the hologram are used to demonstrate this technique. The gray-scale holography of atoms is demonstrated for the first time. Other possibilities of holographic manipulation of atoms are also discussed.

  1. How to avoid simulation sickness in virtual environments during user displacement

    NASA Astrophysics Data System (ADS)

    Kemeny, A.; Colombet, F.; Denoual, T.

    2015-03-01

    Driving simulation (DS) and Virtual Reality (VR) share the same technologies for visualization and 3D vision and may use the same technics for head movement tracking. They experience also similar difficulties when rendering the displacements of the observer in virtual environments, especially when these displacements are carried out using driver commands, including steering wheels, joysticks and nomad devices. High values for transport delay, the time lag between the action and the corresponding rendering cues and/or visual-vestibular conflict, due to the discrepancies perceived by the human visual and vestibular systems when driving or displacing using a control device, induces the so-called simulation sickness. While the visual transport delay can be efficiently reduced using high frequency frame rate, the visual-vestibular conflict is inherent to VR, when not using motion platforms. In order to study the impact of displacements on simulation sickness, we have tested various driving scenarios in Renault's 5-sided ultra-high resolution CAVE. First results indicate that low speed displacements with longitudinal and lateral accelerations under a given perception thresholds are well accepted by a large number of users and relatively high values are only accepted by experienced users and induce VR induced symptoms and effects (VRISE) for novice users, with a worst case scenario corresponding to rotational displacements. These results will be used for optimization technics at Arts et Métiers ParisTech for motion sickness reduction in virtual environments for industrial, research, educational or gaming applications.

  2. Scaling up digital circuit computation with DNA strand displacement cascades.

    PubMed

    Qian, Lulu; Winfree, Erik

    2011-06-01

    To construct sophisticated biochemical circuits from scratch, one needs to understand how simple the building blocks can be and how robustly such circuits can scale up. Using a simple DNA reaction mechanism based on a reversible strand displacement process, we experimentally demonstrated several digital logic circuits, culminating in a four-bit square-root circuit that comprises 130 DNA strands. These multilayer circuits include thresholding and catalysis within every logical operation to perform digital signal restoration, which enables fast and reliable function in large circuits with roughly constant switching time and linear signal propagation delays. The design naturally incorporates other crucial elements for large-scale circuitry, such as general debugging tools, parallel circuit preparation, and an abstraction hierarchy supported by an automated circuit compiler. PMID:21636773

  3. Cavity-mediated collective laser-cooling of an atomic gas inside an asymmetric trap

    E-print Network

    Oleg Kim; Almut Beige

    2015-06-09

    This paper proposes a two-stage process for the collective cooling of a non-interacting atomic gas in a slightly anharmonic, asymmetric trap inside a relatively leaky optical cavity. During the first stage, the displacement stage, the atoms accumulate a small distance away from the trap centre. During the second stage, the cooling stage, a short laser pulse is applied which translates the initial displacement of the particles into a reduction of their vibrational energy with a collectively enhanced cooling rate. If this is followed by another displacement stage and both stages of the proposed cooling process are continuously repeated, the atomic gas is expected to reach a very low temperature.

  4. Graphite filter atomizer in atomic absorption spectrometry

    NASA Astrophysics Data System (ADS)

    Katskov, Dmitri A.

    2007-09-01

    Graphite filter atomizers (GFA) for electrothermal atomic absorption spectrometry (ETAAS) show substantial advantages over commonly employed electrothermal vaporizers and atomizers, tube and platform furnaces, for direct determination of high and medium volatility elements in matrices associated with strong spectral and chemical interferences. Two factors provide lower limits of detection and shorter determination cycles with the GFA: the vaporization area in the GFA is separated from the absorption volume by a porous graphite partition; the sample is distributed over a large surface of a collector in the vaporization area. These factors convert the GFA into an efficient chemical reactor. The research concerning the GFA concept, technique and analytical methodology, carried out mainly in the author's laboratory in Russia and South Africa, is reviewed. Examples of analytical applications of the GFA in AAS for analysis of organic liquids and slurries, bio-samples and food products are given. Future prospects for the GFA are discussed in connection with analyses by fast multi-element AAS.

  5. Job displacement among single mothers: effects on children's outcomes in young adulthood.

    PubMed

    Brand, Jennie E; Thomas, Juli Simon

    2014-01-01

    Given the recent era of economic upheaval, studying the effects of job displacement has seldom been so timely and consequential. Despite a large literature associating displacement with worker well-being, relatively few studies focus on the effects of parental displacement on child well-being, and fewer still focus on implications for children of single-parent households. Moreover, notwithstanding a large literature on the relationship between single motherhood and children's outcomes, research on intergenerational effects of involuntary employment separations among single mothers is limited. Using 30 years of nationally representative panel data and propensity score matching methods, the authors find significant negative effects of job displacement among single mothers on children's educational attainment and social-psychological well-being in young adulthood. Effects are concentrated among older children and children whose mothers had a low likelihood of displacement, suggesting an important role for social stigma and relative deprivation in the effects of socioeconomic shocks on child well-being. PMID:25032267

  6. Direct evidence for atomic defects in graphene layers

    Microsoft Academic Search

    Ayako Hashimoto; Kazu Suenaga; Alexandre Gloter; Koki Urita; Sumio Iijima

    2004-01-01

    Atomic-scale defects in graphene layers alter the physical and chemical properties of carbon nanostructures. Theoretical predictions have recently shown that energetic particles such as electrons and ions can induce polymorphic atomic defects in graphene layers as a result of knock-on atom displacements. However, the number of experimental reports on these defects is limited. The graphite network in single-walled carbon nanotubes

  7. Electrode system for electric-discharge generation of atomic iodine in a repetitively pulsed oxygen - iodine laser with a large active volume

    SciTech Connect

    Kazantsev, S Yu; Kononov, I G; Podlesnykh, S V; Firsov, K N [A M Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    2010-08-03

    Possibilities for increasing the active medium volume of a chemical oxygen - iodine laser (CCOIL) with a pulsed electric-discharge generation of atomic iodine are studied. The reasons are analysed of the low stability of the transverse self-sustained volume discharge in electrode systems with metal cathodes under the conditions of the electric energy input into gas-discharge plasma that are typical for CCOILs: low pressure of mixtures containing a strongly electronegative component, low voltage of discharge burning, low specific energy depositions, and long duration of the current pulse. An efficient electrode system is elaborated with the cathode based on an anisotropically-resistive material, which resulted in a stable discharge in the mixtures of iodide (CH{sub 3}I, n-C{sub 3}H{sub 7}I, C{sub 2}H{sub 5}I) with oxygen and nitrogen at the specific energy depositions of {approx}5 J L{sup -1}, pressures of 10 - 25 Torr, and mixture volume of 2.5 L. (lasers)

  8. Crack border stress and displacement equations revisited

    NASA Technical Reports Server (NTRS)

    Eftis, J.; Subramonian, N.; Liebowitz, H.

    1977-01-01

    It is more or less accepted in fracture mechanics that the elastic stress and displacements very near to the tip of a plane line crack can be approximated with sufficient accuracy, for all geometries and outer boundary loading conditions, by a one-parameter representation, i.e., strictly in terms of the stress intensity factors KI and/or KII. It is shown here that this presumption which appears to be reasonable on face value, quantitatively speaking, is nevertheless unacceptable as a general proposition. The reason lies with the quite arbitrary practice of omitting the second term of the series representation for the stresses, a contribution which is independent of distance from the crack tip. It is not difficult to show by way of specific examples how such omission can lead to error of serious qualitative nature in the prediction of stress and displacement related quantities of interest.

  9. Character displacement of Cercopithecini primate visual signals

    PubMed Central

    Allen, William L.; Stevens, Martin; Higham, James P.

    2014-01-01

    Animal visual signals have the potential to act as an isolating barrier to prevent interbreeding of populations through a role in species recognition. Within communities of competing species, species recognition signals are predicted to undergo character displacement, becoming more visually distinctive from each other, however this pattern has rarely been identified. Using computational face recognition algorithms to model primate face processing, we demonstrate that the face patterns of guenons (tribe: Cercopithecini) have evolved under selection to become more visually distinctive from those of other guenon species with whom they are sympatric. The relationship between the appearances of sympatric species suggests that distinguishing conspecifics from other guenon species has been a major driver of diversification in guenon face appearance. Visual signals that have undergone character displacement may have had an important role in the tribe’s radiation, keeping populations that became geographically separated reproductively isolated on secondary contact. PMID:24967517

  10. Wirelessly Interrogated Position or Displacement Sensors

    NASA Technical Reports Server (NTRS)

    Woodard, Stanley E.; Taylor, Bryant D.

    2007-01-01

    Two simple position or displacement sensors based on inductance-capacitance resonant circuits have been conceived. These sensors are both powered and interrogated without use of wires and without making contact with other objects. Instead, excitation and interrogation are accomplished by means of a magnetic-field-response recorder. Both of the present position or displacement sensors consist essentially of variable rectangular parallel-plate capacitors electrically connected in series with fixed inductors. Simple inductance-capacitance circuits of the type used in these sensors are inherently robust; their basic mode of operation does not depend on maintenance of specific environmental conditions. Hence, these sensors can be used under such harsh conditions as cryogenic temperatures, high pressures, and radioactivity.

  11. Air displacement plethysmography: cradle to grave.

    PubMed

    Fields, David A; Gunatilake, Ravindu; Kalaitzoglou, Evangelia

    2015-04-01

    Differences in body composition are associated with increased disease risk in various stages of life. Despite numerous available methods in assessing body composition (air displacement plethysmography, dual-energy X-ray absorptiometry, bioelectrical impedance, hydrometry, and magnetic resonance imaging), due to innate technical limitations, the ability for one singular method to track body composition over the life span (ie, infancy to adulthood) is challenging and imperfect. The primary goal of this review is to determine if there are body composition methods that can accurately track body composition from infancy into adulthood. After careful consideration and taking into account the best available scientific evidence, we feel air displacement plethysmography is the best instrument at this time for tracking body composition, starting in infancy and forward into adulthood, partly because it is the only "practical" clinical tool currently available for use during infancy. PMID:25761768

  12. Conditional displacement operator for traveling fields

    NASA Astrophysics Data System (ADS)

    Souza, Simone; Avelar, A. T.; Malbouisson, J. M. C.; Baseia, B.

    2008-05-01

    We show that the conditional displacement operator U=exp[bbˆ(?a-??aˆ)] acting upon arbitrary states of traveling waves can be well approximated by the action of a Kerr-medium placed between two beam splitters whose respective second ports are fed by highly excited coherent states. The scheme is deterministic, since it does not employ any detection event. Applications for generation of nonclassical states and measurement of Wigner function of arbitrary states are also considered.

  13. Optoelectronic Displacement Measurement Method for Rotating Disks

    Microsoft Academic Search

    C. E. Bakis; B. J. Haldeman; R. P. Emerson

    Radial displacements on an axial surface of a rotating disk can be measured with optoelectronic sensing devices consisting\\u000a of infrared emitters and phototransistors. The aim of this investigation is to improve the stability and robustness of a previously\\u000a described optoelectronic measurement system. Stability is improved by a computerized algorithm for the control of the emitter\\u000a intensity based on feedback from

  14. Coreflood experimental study of steam displacement 

    E-print Network

    Cerutti, Andres Enrique

    1997-01-01

    COREFLOOD EXPERIMENTAL STUDY OF STEAM DISPI ACEMENT A Thesis by ANDRE S ENRIQUE CERUTTI Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... December 1997 Major Subject: Petroleum Engineering COREFLOOD EXPERIMENTAL STUDY OF STEAM DISPLACEMENT A Thesis by ANDRES ENRIQUE CERUTTI Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirements...

  15. Fiber Optic Sensing System Measures Small Displacements

    NASA Technical Reports Server (NTRS)

    Adamovsky, Grigory

    1994-01-01

    Fiber optic sensing system measures small changes in intensity of light propagating through its interferometric sensing head. Quantity determined using this approach is displacement or any other phenomenon that affects intensity of light. Sensing scheme involves imbalanced fiber optic interferometer as sensing head and amplitude modulation and detection at two radio frequencies. One important advantage over prior fiber sensors involving pulse-amplitude modulation is length of imbalance shorter.

  16. Effects of Young's modulus on fault displacement

    Microsoft Academic Search

    Agust Gudmundsson

    2004-01-01

    Elastic crack models predict a linear relationship between displacement (u) and rupture (trace) length (L) during slip in a fault zone. Attempts to find universal-scaling laws for L\\/u, however, have generally failed. Here I propose that these attempts have failed because they do not take into account the changes in the mechanical properties, in particular Young's modulus (stiffness), of the fault

  17. Measurement of Object Displacement Using Phase Stepped, Real-Time Holographic Interferometry

    Microsoft Academic Search

    Benjie Ovryn

    1992-01-01

    Phase stepped holographic interferometry is a noncontact method for measuring displacements over a large field of view with a precision of about 5 nm. The whole -field capabilities and high sensitivity of this method make it potentially unrivaled for measuring spatial inhomogeneities, for example, the proposed spatial variation of the piezoelectric coefficient in cortical bone. This dissertation has advanced the

  18. Characterizing Miscible Displacements in Heterogeneous Reservoirs Using the Karhunen–Loéve Decomposition

    Microsoft Academic Search

    Ridha B. Gharbi; Fuad Qasem; Nejib Smaoui

    2003-01-01

    The article describes the application of the Karhunen–Loéve (K–L) decomposition in characterizing miscible displacements in geostatistically generated permeable media. A large number of simulation runs were performed in several heterogeneous reservoirs, each with different dimensionless scaling groups, and the spatial fluid concentrations were mapped at various times. The heterogeneous permeable media were generated geostatistically using the Matrix Decomposition Method with

  19. Are Children Really Inferior Goods? Evidence from Displacement-Driven Income Shocks

    ERIC Educational Resources Information Center

    Lindo, Jason M.

    2010-01-01

    This paper explores the causal link between income and fertility by analyzing women's fertility response to the large and permanent income shock generated by a husband's job displacement. I find that the shock reduces total fertility, suggesting that the causal effect of income on fertility is positive. A model that incorporates the time cost of…

  20. Lubricant film thickness measurement using fiber-optic Michelson interferometer and fiber-optic displacement sensor

    Microsoft Academic Search

    Yuping Chen; Xiaodong Zhang; Ping Zhang; Chunxiang Liu

    2009-01-01

    How to accurately measure the lubricant film thickness of the hydrodynamic slide bearings has been an important research field in the condition monitor and fault diagnosis of large rotary machinery. This paper focus on a new detection approach using a fiber-optical Michelson Interferometer combined with a fiber-optical displacement sensor for the lubricant film thickness measurement. After introducing the fundamental principle,

  1. Interplate coupling beneath NE Japan inferred from three-dimensional displacement field

    Microsoft Academic Search

    Yoko Suwa; Satoshi Miura; Akira Hasegawa; Toshiya Sato; Kenji Tachibana

    2006-01-01

    The northeastern Japan arc is located in a typical subduction zone and is a seismically active region where large interplate earthquakes have occurred repeatedly. The nationwide GPS network has made it possible to investigate the crustal deformation in unprecedented detail; however, vertical displacements are less accurate than the horizontal ones and have not been used to constrain interplate coupling models.

  2. A smooth approximation of mobile platform displacement for Mobile Haptic Alessandro Formaglio Domenico Prattichizzo

    E-print Network

    Siena, Università di

    are multirate devices where the displacement sampling of mobile platform may affect the quality of haptic render of haptic rendering. 1. Introduction One of the factors affecting the realism of Virtual Re- ality/position (force/velocity) control algorithm is re- quired [8] to achieve realistic haptic interaction inside large

  3. Displacement of Black Teachers in the Eleven Southern States. Special Report.

    ERIC Educational Resources Information Center

    Hooker, Robert W.

    In order to collect information on teacher displacement, the Race Relations Information Center surveyed white and black teachers and principals, teacher association executives, attorneys, civil rights and community leaders, state and federal officials, and journalists in 11 Southern states; the survey was conducted largely by phone. Several…

  4. Road displacement model based on structural mechanics

    NASA Astrophysics Data System (ADS)

    Lu, Xiuqin; Guo, Qingsheng; Zhang, Yi

    2006-10-01

    Spatial conflict resolution is an important part of cartographic generalization, and it can deal with the problems of having too much information competing for too little space, while feature displacement is a primary operator of map generalization, which aims at resolving the spatial conflicts between neighbor objects especially road features. Considering the road object, this paper explains an idea of displacement based on structural mechanics. In view of spatial conflict problem after road symbolization, it is the buffer zones that are used to detect conflicts, then we focus on each conflicting region, with the finite element method, taking every triangular element for analysis, listing stiffness matrix, gathering system equations and calculating with iteration strategy, and we give the solution to road symbol conflicts. Being like this until all the conflicts in conflicting regions are solved, then we take the whole map into consideration again, conflicts are detected by reusing the buffer zones and solved by displacement operator, so as to all of them are handled.

  5. Comparing Teaching Approaches About Maxwell's Displacement Current

    NASA Astrophysics Data System (ADS)

    Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

    2014-08-01

    Due to its fundamental role for the consolidation of Maxwell's equations, the displacement current is one of the most important topics of any introductory course on electromagnetism. Moreover, this episode is widely used by historians and philosophers of science as a case study to investigate several issues (e.g. the theory-experiment relationship). Despite the consensus among physics educators concerning the relevance of the topic, there are many possible ways to interpret and justify the need for the displacement current term. With the goal of understanding the didactical transposition of this topic more deeply, we investigate three of its domains: (1) The historical development of Maxwell's reasoning; (2) Different approaches to justify the term insertion in physics textbooks; and (3) Four lectures devoted to introduce the topic in undergraduate level given by four different professors. By reflecting on the differences between these three domains, significant evidence for the knowledge transformation caused by the didactization of this episode is provided. The main purpose of this comparative analysis is to assist physics educators in developing an epistemological surveillance regarding the teaching and learning of the displacement current.

  6. Simultaneous muscle force and displacement transducer

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Culler, V. H. (inventors)

    1980-01-01

    A myocardial transducer for simultaneously measuring force and displacement within a very small area of myocardium is disclosed. The transducer comprised of an elongated body forked at one end to form an inverted Y shaped beam with each branch of the beam constituting a low compliant tine for penetrating the myocardium to a predetermined depth. Bonded to one of the low compliance tines is a small piezoresistive element for converting a force acting on the beam into an electrical signal. A third high compliant tine of the transducer, which measures displacement of the myocardium in a direction in line with the two low compliant tines, is of a length that just pierces the surface membrane. A small piezoresistive element is bonded to the third tine at its upper end where its bending is greatest. Displacement of the myocardium causes a deformation in curvature of the third tine, and the second small piezoresistive element bonded to the surface of its curved end converts its deformation into an electrical signal.

  7. 46 CFR 153.966 - Discharge by liquid displacement.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 2010-10-01 false Discharge by liquid displacement. 153.966 Section 153...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS...Procedures § 153.966 Discharge by liquid displacement. The person in...

  8. 46 CFR 153.966 - Discharge by liquid displacement.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2011-10-01 false Discharge by liquid displacement. 153.966 Section 153...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS...Procedures § 153.966 Discharge by liquid displacement. The person in...

  9. Isolation of monoclonal antibody charge variants by displacement chromatography.

    PubMed

    McAtee, C Patrick; Hornbuckle, Jacob

    2012-08-01

    This unit discusses the important parameters in designing and optimizing a separation of monoclonal antibody (mAb) charge variants from process streams by ion-exchange displacement chromatography, including sample preparation and selection of matrix, column, and appropriate buffer. A protocol is provided for determination of optimal column binding and displacement conditions, including cleaning and regeneration of the displacement columns. PMID:22851499

  10. Tsunami mortality and displacement in Aceh province, Indonesia

    E-print Network

    Scharfstein, Daniel

    Tsunami mortality and displacement in Aceh province, Indonesia Abdur Rofi, MA Mercy Corps Indonesia of 388 Indonesian households displaced by the December 2004 tsunami was conducted in Aceh province in February 2005.Of tsunami-displaced households in Aceh Barat and Nagan Raya districts,61.8 per cent reported

  11. From Word to Image: Displacement and Meaning in "Greed."

    ERIC Educational Resources Information Center

    Grindon, Leger

    1989-01-01

    Describes levels of displacement in Stroheim's film "Greed," including (1) the displacement of reason, pleasure, and life by the desire for gold; and (2) the displacement that points to a double movement in Stroheim's cinematic style. Argues that the film's sense of doom arises from the psychic nightmare operating through the mechanics of…

  12. Induction Machine Analysis for Arbitrary Displacement Between Multiple Winding Sets

    Microsoft Academic Search

    R. H. Nelson; P. C. Krause

    1974-01-01

    The steps in t he applied voltages of a three-phase, inverter-induction motor drive system cause undesirable pulsations in motortor By using multiple inverters connected to a multiphase machine with appropriate winding displacements, significant improvement in system performance is possible. The winding displacements required, however, are not necessarily the symmetrical displacements used in standard multiphase machines. This paper sets forth an

  13. Miscible displacement of salinity fronts: Implications for colloid mobilization

    E-print Network

    Flury, Markus

    Miscible displacement of salinity fronts: Implications for colloid mobilization Markus Flury, James on the hydrodynamic stability of the salinity displacement front. A series of experiments was conducted in packed columns where a solution of 1000 mM NaCl was displaced by 1 mM NaNO3 in a saturated porous medium

  14. Atomic supersymmetry

    NASA Technical Reports Server (NTRS)

    Kostelecky, V. Alan

    1993-01-01

    Atomic supersymmetry is a quantum-mechanical supersymmetry connecting the properties of different atoms and ions. A short description of some established results in the subject are provided and a few recent developments are discussed including the extension to parabolic coordinates and the calculation of Stark maps using supersymmetry-based models.

  15. Target micro-displacement measurement by a "comb" structure of intensity distribution in laser plasma propulsion

    NASA Astrophysics Data System (ADS)

    Zheng, Z. Y.; Zhang, S. Q.; Gao, L.; Gao, H.

    2015-05-01

    A "comb" structure of beam intensity distribution is designed and achieved to measure a target displacement of micrometer level in laser plasma propulsion. Base on the "comb" structure, the target displacement generated by nanosecond laser ablation solid target is measured and discussed. It is found that the "comb" structure is more suitable for a thin film target with a velocity lower than tens of millimeters per second. Combing with a light-electric monitor, the `comb' structure can be used to measure a large range velocity.

  16. Tracking log displacement during floods in the Tagliamento River using RFID and GPS tracker devices

    NASA Astrophysics Data System (ADS)

    Ravazzolo, D.; Mao, L.; Picco, L.; Lenzi, M. A.

    2015-01-01

    Large pieces of in-channel wood can exert an important role on the ecological and morphological properties of gravel-bed rivers. On the other side, when transported during flood events, large wood can become a source of risk for sensitive structures such as bridges. However, wood displacement and velocity in river systems are still poorly understood, especially in large gravel-bed rivers. This study focuses on log transport in a valley reach of Tagliamento River (Italy). Log displacement during flood events of different magnitudes recorded from June 2010 to October 2011 has been analysed thanks to the installation of 113 radio frequency identification (RFID) tags and 42 GPS tracker devices in logs of different dimensions. Recovery rates of logs equipped with RFID and GPS trackers were about 43% and 42%, respectively. The GPS devices allowed us to analyse in details the log displacement and transport overtime, indicating a higher log entrainment during rising limb of hydrographs. The threshold for the entrainment of logs from low bars is around 40% of bankfull water stage. No clear relationship was found between the peak of flood and log displacement length and velocity. However, log displacement length and velocity appear significantly correlated to the ratio between the peak of flow and the water stage exceeding the flow duration curve for 25% of time (i.e. the ratio hmax/h25 ratio). Log deposition was observed to occur at the peak flow, and logs transported during ordinary events are preferably deposited on low bars. This study reveals the potentials of GPS tracker devices to monitor the entrainment and movements of logs in large gravel-bed rivers during floods. These observations could be useful for better planning of river management practices and strategies involving the use of large wood pieces and could help for calibrating wood budgets at the reach scale.

  17. Displacement Energy Surface in 3C and 6H SiC

    SciTech Connect

    Devanathan, Ramaswami; Weber, William J.

    2000-02-29

    The phase stability of 3C-SiC upon heating and the threshold displacement energy (Ed) surfaces for C and Si primary knock-on atoms (PKAs) in 3C-SiC and 6H-SiC have been investigated using molecular dynamics simulations. A recently optimized Tersoff potential is used in conjunction with an ab initio repulsive potential to represent the interactions between atoms. The simulations provide important insights into phase separation of SiC upon heating, and indicate a strong anisotropy in the Ed surface for both Si and C PKAs. The two polytypes show many similarities in the nature of the Ed surface. The average displacement energy is separately determined by simulating 30 different 500 eV cascades in 3C-SiC. The minimum displacement energies of 21 eV for C and 35 eV for Si are in excellent agreement with interpretation of experimental observations and the simulations of 500 eV cascades.

  18. Correlation between Displacement Damage Dose and Proton Irradiation Effects on GaInP\\/GaAs\\/Ge Space Solar Cells

    Microsoft Academic Search

    Yun-Hong Liu; Rong Wang; Xin-Yu Cui; Yong-Xia Wang

    2009-01-01

    The irradiation effects of 0.28-2.80 MeV protons on GaInP\\/GaAs\\/Ge solar cells have been analysed, and then correlated with the displacement damage dose. The results of I-V and spectral response measurements, combined with the SRIM-derived vacancies produced rates, show that the degradation of the solar cells is largely determined by the displacement damage of the GaAs sub-cell. Thus the SRIM-derived NIEL

  19. Model of delocalized atoms in the physics of the vitreous state

    SciTech Connect

    Sanditov, D. S., E-mail: Sanditov@bsu.ru [Buryat State University (Russian Federation)

    2012-07-15

    A development of the model of delocalized atoms of liquids and glasses is proposed. It is shown that the basic equation of the model for the probability of delocalization (excitation) of an atom can be obtained not only from the Clausius relation but also by other methods of statistical physics. Techniques for calculating the parameters of the model are developed. The critical displacement of an atom from the equilibrium position, which corresponds to the maximum interatomic attraction force, can be considered as a delocalization (local excitation) of this atom in an elastic continuum. The energy of the critical displacement of an atom calculated as the work of the limit elastic deformation of the interatomic bond in an elastic continuum is in agreement with the results of calculation by the model of delocalized atoms. This energy can also be calculated from the data on surface tension and atomic volume. In silicate glasses, the process of delocalization of an atom represents the critical displacement of a bridging oxygen atom in the structural fragment of a silicon-oxygen (Si-O-Si) network before the switching of the valence bond, whereas, in amorphous organic polymers, the delocalization of an atom corresponds to the limit displacement of a fragment of the main chain of a macromolecule (a group of atoms in the connecting link).

  20. Poly(1,3,4-oxadiazoles) via aromatic nucleophilic displacement

    NASA Technical Reports Server (NTRS)

    Connell, John W. (inventor); Hergenrother, Paul M. (inventor); Wolf, Peter (inventor)

    1992-01-01

    Poly(1,3,4-oxadiazoles) (POX) are prepared by the aromatic nucleophilic displacement reaction of di(hydroxyphenyl) 1,3,4-oxadiazole monomers with activated aromatic dihalides or activated aromatic dinitro compounds. The polymerizations are carried out in polar aprotic solvents such as sulfolane or diphenylsulfone using alkali metal bases such as potassium carbonate at elevated temperatures under nitrogen. The di(hydroxyphenyl) 1,3,4-oxadiazole monomers are synthesized by reacting 4-hydroxybenzoic hydrazide with phenyl 4-hydrobenzoate in the melt and also by reacting aromatic dihydrazides with two moles of phenyl 4-hydroxybenzoate in the melt. This synthetic route has provided high molecular weight POX of new chemical structure, is economically and synthetically more favorable than other routes, and allows for facile chemical structure variation due to the large variety of activated aromatic dihalides which are available.

  1. Molecule-displacive ferroelectricity in organic supramolecular solids

    NASA Astrophysics Data System (ADS)

    Ye, Heng-Yun; Zhang, Yi; Noro, Shin-Ichiro; Kubo, Kazuya; Yoshitake, Masashi; Liu, Zun-Qi; Cai, Hong-Ling; Fu, Da-Wei; Yoshikawa, Hirofumi; Awaga, Kunio; Xiong, Ren-Gen; Nakamura, Takayoshi

    2013-07-01

    Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10 kHz), and high performance in polarization switching up to 1 × 106 times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.

  2. Displaced and non-displaced Colombian children's evaluations of moral transgressions, retaliation, and reconciliation

    PubMed Central

    Ardila-Rey, Alicia; Killen, Melanie; Brenick, Alaina

    2015-01-01

    In order to assess the effects of displacement and exposure to violence on children's moral reasoning, Colombian children exposed to minimal violence (non-displaced or low-risk) (N = 99) and to extreme violence (displaced or high-risk) (N = 94), evenly divided by gender, at 6-, 9-, and 12 - years of age, were interviewed regarding their evaluation of peer-oriented moral transgressions (hitting and not sharing toys). The vast majority of children evaluated moral transgressions as wrong. Group and age differences were revealed, however, regarding provocation and retaliation. Children who were exposed to violence, in contrast to those with minimum exposure, judged it more legitimate to inflict harm or deny resources when provoked and judged it more okay to retaliate for reasons of retribution. Surprisingly, and somewhat hopefully, all children viewed reconciliation as feasible. The results are informative regarding theories of morality, culture, and the effects of violence on children's social development. PMID:25722543

  3. Bayesian Speckle Tracking. Part I: An Implementable Perturbation to the Likelihood Function for Ultrasound Displacement Estimation

    PubMed Central

    Byram, Brett; Trahey, Gregg E.; Palmeri, Mark

    2012-01-01

    A hallmark of clinical ultrasound has been accurate and precise displacement estimation. Displacement estimation accuracy has largely been considered to be limited by the Cramer-Rao lower bound (CRLB). However, the CRLB only describes the minimum variance obtainable from unbiased estimators. Unbiased estimators are generally implemented using Bayes’ theorem, which requires a likelihood function. The classic likelihood function for the displacement estimation problem is not discriminative and hard to implement for clinically relevant ultrasound with diffuse scattering. Since the classic likelihood function is not effective a perturbation is proposed. The proposed likelihood function was evaluated and compared against the classic likelihood function by converting both to posterior probability density functions (PDFs) using a non-informative prior. Example results are reported for bulk motion simulations using a 6? tracking kernel and 30 dB SNR for 1000 data realizations. The canonical likelihood function assigned the true displacement a mean probability of only 0.070±0.020, while the new likelihood function assigned the true displacement a much higher probability of 0.22±0.16. The new likelihood function shows improvements at least for bulk motion, acoustic radiation force induced motion and compressive motion, and at least for SNRs greater than 10 dB and kernel lengths between 1.5 and 12?. PMID:23287920

  4. A Mechanical Model of Neural Tissue Displacement During Lorentz Effect Imaging

    PubMed Central

    Roth, Bradley J.; Basser, Peter J.

    2009-01-01

    Song and co-workers recently proposed a method for MRI detection of biocurrents in nerves called “Lorentz Effect Imaging”. When exposed to a magnetic field, neural currents are subjected to a Lorentz force that moves the nerve. If the displacement is large enough, an artifact is predicted in the MR signal. In this paper, the displacement of a nerve of radius a in a surrounding tissue of radius b and shear modulus µ is analyzed. The nerve carries a current density J and lies in a magnetic field B. The solution to the resulting elasticity problem indicates that the nerve moves a distance BJ4?a2ln(ba). Using realistic parameters for a human median nerve in a 4 T field, this calculated displacement is 0.013 µm or less. The distribution of displacement is widespread throughout the tissue, and is not localized near the nerve. This displacement is orders of magnitude too small to be observed by conventional MRI methods. PMID:19097218

  5. Fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap

    SciTech Connect

    Heo, Myoung-Sun; Choi, Jae-yoon; Shin, Yong-il [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

    2011-01-15

    We demonstrate a fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap. A single global minimum of the trapping potential is generated by slightly displacing the plug beam from the center of the quadrupole field. With a dark magneto-optical trap and a simple rf evaporation, our system produces a condensate with N{approx_equal}10{sup 7} atoms every 17 s. The Majorana loss rates and the resultant heating rates for various temperatures are measured with and without plugging. The average energy of a spin-flipped atom is almost linearly proportional to temperature and determined to be about 60% of the average energy of a trapped atom. We present a numerical study of the evaporation dynamics in a plugged linear trap.

  6. Laser-stimulated atomic migration

    Microsoft Academic Search

    WILBUR M. FRANKLIN; PAPIYA SENGUPTA

    1972-01-01

    The effects of stimulated Raman scattering (SRS) and of infrared (IR) absorption on the scattering at defects leading to atomic migration in solids is evaluated in detail for certain systems.DeltaE\\/kT approx sum u_{ic}^{2}\\/langleu_{i}u_{i}rangle, whereDeltaEis the activation energy, uicis the many-body critical displacement in a migration event, andlangleu_{i}u_{i}rangleis the equal-time correlation function including anharmonic terms. Using the equal-time correlation for the

  7. Fiber-optic displacement sensor system 

    E-print Network

    Cava, Norayda Nora

    1990-01-01

    FIBER-OPTIC DISPLACEMENT SENSOR SYSTEM A Thesis by NORAYDA NORA CAVA Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 1990 Major Subject... and non-invasive sensing [2]. Commercially and militarily, the development of "smart skins", in which structural components are made of composite materials, has led to a need for fiber-optic based sensors [3], [4] which can be imbedded within those...

  8. Dynamics and structure of energetic displacement cascades

    SciTech Connect

    Averback, R.S.; Diaz de la Rubia, T.; Benedek, R.

    1987-12-01

    This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by molecular dynamics. Recent application of this simulation technique to Cu and Ni provides new insight into the dynamics of cascade processes. On the experimental side, new data on ion beam mixing and in situ electron microscopy studies of ion damage at low temperatures reveal the role of the thermodynamic properties of the material on cascade dynamics and structure. 38 refs., 9 figs.

  9. Superconducting inductive displacement detection of a microcantilever

    E-print Network

    Vinante, Andrea

    2014-01-01

    We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 $\\mu$T, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at $4.2$ K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

  10. Superconducting inductive displacement detection of a microcantilever

    E-print Network

    Andrea Vinante

    2014-05-14

    We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 $\\mu$T, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at $4.2$ K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

  11. Superconducting inductive displacement detection of a microcantilever

    NASA Astrophysics Data System (ADS)

    Vinante, A.

    2014-07-01

    We demonstrate a superconducting inductive technique to measure the displacement of a micromechanical resonator. In our scheme, a type I superconducting microsphere is attached to the free end of a microcantilever and approached to the loop of a dc Superconducting Quantum Interference Device (SQUID) microsusceptometer. A local magnetic field as low as 100 ?T, generated by a field coil concentric to the SQUID, enables detection of the cantilever thermomechanical noise at 4.2 K. The magnetomechanical coupling and the magnetic spring are in good agreement with image method calculations assuming pure Meissner effect. These measurements are relevant to recent proposals of quantum magnetomechanics experiments based on levitating superconducting microparticles.

  12. Combining solvent thermodynamic profiles with functionality maps of the Hsp90 binding site to predict the displacement of water molecules.

    PubMed

    Haider, Kamran; Huggins, David J

    2013-10-28

    Intermolecular interactions in the aqueous phase must compete with the interactions between the two binding partners and their solvating water molecules. In biological systems, water molecules in protein binding sites cluster at well-defined hydration sites and can form strong hydrogen-bonding interactions with backbone and side-chain atoms. Displacement of such water molecules is only favorable when the ligand can form strong compensating hydrogen bonds. Conversely, water molecules in hydrophobic regions of protein binding sites make only weak interactions, and the requirements for favorable displacement are less stringent. The propensity of water molecules for displacement can be identified using inhomogeneous fluid solvation theory (IFST), a statistical mechanical method that decomposes the solvation free energy of a solute into the contributions from different spatial regions and identifies potential binding hotspots. In this study, we employed IFST to study the displacement of water molecules from the ATP binding site of Hsp90, using a test set of 103 ligands. The predicted contribution of a hydration site to the hydration free energy was found to correlate well with the observed displacement. Additionally, we investigated if this correlation could be improved by using the energetic scores of favorable probe groups binding at the location of hydration sites, derived from a multiple copy simultaneous search (MCSS) method. The probe binding scores were not highly predictive of the observed displacement and did not improve the predictivity when used in combination with IFST-based hydration free energies. The results show that IFST alone can be used to reliably predict the observed displacement of water molecules in Hsp90. However, MCSS can augment IFST calculations by suggesting which functional groups should be used to replace highly displaceable water molecules. Such an approach could be very useful in improving the hit-to-lead process for new drug targets. PMID:24070451

  13. Gender-based violence in conflict and displacement: qualitative findings from displaced women in Colombia

    PubMed Central

    2014-01-01

    Introduction Gender-based violence (GBV) is prevalent among, though not specific to, conflict affected populations and related to multifarious levels of vulnerability of conflict and displacement. Colombia has been marked with decades of conflict, with an estimated 5.2 million internally displaced persons (IDPs) and ongoing violence. We conducted qualitative research to understand the contexts of conflict, displacement and dynamics with GBV. This as part of a multi-phase, mixed method study, in collaboration with UNHCR, to develop a screening tool to confidentially identify cases of GBV for referral among IDP women who were survivors of GBV. Methods Qualitative research was used to identify the range of GBV, perpetrators, contexts in conflict and displacement, barriers to reporting and service uptake, as well as to understand experiences of service providers. Thirty-five female IDPs, aged 18 years and older, who self-identified as survivors of GBV were enrolled for in-depth interviews in San Jose de Guaviare and Quibdo, Colombia in June 2012. Thirty-one service providers participated in six focus group discussions and four interviews across these sites. Results Survivors described a range of GBV across conflict and displacement settings. Armed actors in conflict settings perpetrated threats of violence and harm to family members, child recruitment, and, to a lesser degree, rape and forced abortion. Opportunistic violence, including abduction, rape, and few accounts of trafficking were more commonly reported to occur in the displacement setting, often perpetrated by unknown individuals. Intrafamilial violence, intimate partner violence, including physical and sexual violence and reproductive control were salient across settings and may be exacerbated by conflict and displacement. Barriers to reporting and services seeking were reported by survivors and providers alike. Conclusions Findings highlight the need for early identification of GBV cases, with emphasis on confidential approaches and active engagement of survivors in available, quality services. Such efforts may facilitate achievement of the goals of new Colombian laws, which seek to prevent and respond to GBV, including in conflict settings. Ongoing conflict and generalized GBV in displacement, as well as among the wider population, suggests a need to create sustainable solutions that are accessible to both IDPs and general populations. PMID:25076981

  14. Selective displacement chromatography in multimodal cation exchange systems.

    PubMed

    Sheth, Rahul D; Morrison, Christopher J; Cramer, Steven M

    2011-12-23

    A library of displacer analogues with varying degrees of electrostatic, hydrophobic and hydrogen bonding moieties was evaluated for their ability to enhance the selectivity of multimodal (MM) chromatography under high loading conditions. The library was screened for displacement of model proteins using a robotic liquid handling system and selective batch separations were achieved for proteins that were inseparable with linear gradient chromatography. Trends in protein displacement were identified and displacers with higher hydrophobicity and net charge exhibited improved protein displacements. Proteins that interacted with the resins primarily via electrostatic interactions were more readily displaced than those that possessed a significant hydrophobic contribution to their binding. In addition, multimodal displacers were found to be more selective than single mode electrostatic displacers. Column chromatography studies were also carried out and baseline separations were achieved for model protein pairs using selective displacement. Finally, operation of these columns in the desorption mode resulted in baseline separation of model proteins which were not separable by selective displacement chromatography. This study indicates that the inherent selectivity of MM resins can be augmented by the selectivity of the displacer under non-linear competitive binding conditions, creating new opportunities for protein separations not possible using traditional gradient operations. PMID:22098931

  15. Attenuation of Scalar Fluxes Measured with Spatially-displaced Sensors

    NASA Astrophysics Data System (ADS)

    Horst, T. W.; Lenschow, D. H.

    2009-02-01

    Observations from the Horizontal Array Turbulence Study (HATS) field program are used to examine the attenuation of measured scalar fluxes caused by spatial separation between the vertical velocity and scalar sensors. The HATS data show that flux attenuation for streamwise, crosswind, and vertical sensor displacements are each a function of a dimensionless, stability-dependent parameter n m multiplied by the ratio of sensor displacement to measurement height. The scalar flux decays more rapidly with crosswind displacements than for streamwise displacements and decays more rapidly for stable stratification than for unstable stratification. The cospectral flux attenuation model of Kristensen et al. agrees well with the HATS data for streamwise sensor displacements, although it is necessary to include a neglected quadrature spectrum term to explain the observation that flux attenuation is often less with the scalar sensor downwind of the anemometer than for the opposite configuration. A simpler exponential decay model provides good estimates for crosswind sensor displacements, as well as for streamwise sensor displacements with stable stratification. A model similar to that of Lee and Black correctly predicts flux attenuation for a combination of streamwise and crosswind displacements, i.e. as a function of wind direction relative to the sensor displacement. The HATS data for vertical sensor displacements extend the near-neutral results of Kristensen et al. to diabatic stratification and confirm their finding that flux attenuation is less with the scalar sensor located below the anemometer than if the scalar sensor is displaced an equal distance either horizontally or above the anemometer.

  16. Displacement chromatography of proteins on hydrophobic charge induction adsorbent column.

    PubMed

    Zhao, Guofeng; Sun, Yan

    2007-09-21

    Displacement chromatography of protein mixtures is proposed on hydrophobic charge induction chromatography (HCIC). We have used an HCIC medium, MEP-Hypercel as the stationary phase and a quaternary ammonium salt, benzethonium chloride, as the displacer. It was found that the multiple interactions between proteins/displacer and the HCIC sorbent, i.e. hydrophobic interaction and charge repulsion, enabled a greater flexibility for the design of displacement processes and ease of column regeneration by adjustment of pH. The capacity factors of proteins and displacers were used to predict their performances in column displacement, and the experimental results agreed well with the prediction. An isotachic displacement train of lysozyme and alpha-chymotrypsinogen A was formed with benzethonium chloride as the displacer at pH 5.0 with good yields and purities of the two proteins. Column regeneration was efficiently achieved by charge repulsion between the displacer and the adsorbent at lower pH values (pH 3 and 4). The results indicate that the displacement chromatography on HCIC is a good alternative to traditional hydrophobic displacement chromatography. PMID:17692858

  17. An atomic model of crack tip deformation in aluminum using an embedded atom potential

    SciTech Connect

    Hoagland, R.G. (Washington State University, Pullman, Washington 99164-2920 (USA)); Daw, M.S.; Foiles, S.M.; Baskes, M.I. (Sandia National Laboratory, Livermore, California 94551-0969 (USA))

    1990-02-01

    The atomic configuration at the tip of a mode 1 crack in aluminum is modeled by means of molecular dynamics calculations using an embedded atom potential. This potential intrinsically incorporates many-body contributions. This paper is concerned with the characteristics of the atomic displacement fields in comparison to the linear elastic predictions and dislocation emission phenomena. Three crack/crystal orientations are examined in which the crack plane-crack propagation directions are (010)-(100), ({bar 1}10)-(110), and ({bar 1}10)-(111). The first two models behaved in a brittle fashion as dislocation emission did not occur for reasons associated with the use of periodic boundary conditions parallel to the crack front. For the models which remained atomically sharp, the positions of the atoms near the crack tip in equilibrium configurations are different from the linear elastic predictions but, to first order, retain an {ital r}{sup 1/2} dependence, with smaller {ital K}, and with the origin displaced behind the physical crack tip. This near tip region is also observed to be elastically softer than in the far field. Dislocation emission readily proceeds in the ({bar 1}10)-(111) model by the sequential emission of partials with attendant nonzero {ital u}{sub {ital z}} displacements. The blunting is characterized by the creation of two corner defects that separate as emission occurs and relaxation of the strains in the region initially confronted by the crack tip. Additional features of the results are discussed.

  18. Resonant Atom-Dimer Relaxation in Ultracold Atoms

    E-print Network

    Kerstin Helfrich; H. -W. Hammer

    2009-07-03

    Three-body systems with large scattering length display universal phenomena associated with a discrete scaling symmetry. These phenomena include resonant enhancement of three-body loss rates when an Efimov three-body resonance is at the scattering threshold. In particular, there can be resonant peaks in the atom-dimer relaxation rate for large positive scattering length. We improve upon earlier studies and calculate the atom-dimer relaxation rate as a function of temperature using a Bose-Einstein distribution for the thermal average. As input, we use calculations of the atom-dimer scattering phase shifts from effective field theory.

  19. Mapping Out Atom-Wall Interaction with Atomic Clocks

    SciTech Connect

    Derevianko, A.; Obreshkov, B. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); Dzuba, V. A. [Department of Physics, University of Nevada, Reno, Nevada 89557 (United States); School of Physics, University of New South Wales, Sydney, 2052 (Australia)

    2009-09-25

    We explore the feasibility of probing atom-wall interaction with atomic clocks based on atoms trapped in engineered optical lattices. Optical lattice is normal to the wall. By monitoring the wall-induced clock shift at individual wells of the lattice, one would measure the dependence of the atom-wall interaction on the atom-wall separation. We find that the induced clock shifts are large and observable at already experimentally demonstrated levels of accuracy. We show that this scheme may uniquely probe the long-range atom-wall interaction in all three qualitatively distinct regimes of the interaction: van der Waals (image-charge interaction), Casimir-Polder (QED vacuum fluctuations), and Lifshitz (thermal-bath fluctuations) regimes.

  20. Mapping out atom-wall interaction with atomic clocks.

    PubMed

    Derevianko, A; Obreshkov, B; Dzuba, V A

    2009-09-25

    We explore the feasibility of probing atom-wall interaction with atomic clocks based on atoms trapped in engineered optical lattices. Optical lattice is normal to the wall. By monitoring the wall-induced clock shift at individual wells of the lattice, one would measure the dependence of the atom-wall interaction on the atom-wall separation. We find that the induced clock shifts are large and observable at already experimentally demonstrated levels of accuracy. We show that this scheme may uniquely probe the long-range atom-wall interaction in all three qualitatively distinct regimes of the interaction: van der Waals (image-charge interaction), Casimir-Polder (QED vacuum fluctuations), and Lifshitz (thermal-bath fluctuations) regimes. PMID:19905511

  1. Regression models for estimating coseismic landslide displacement

    USGS Publications Warehouse

    Jibson, R.W.

    2007-01-01

    Newmark's sliding-block model is widely used to estimate coseismic slope performance. Early efforts to develop simple regression models to estimate Newmark displacement were based on analysis of the small number of strong-motion records then available. The current availability of a much larger set of strong-motion records dictates that these regression equations be updated. Regression equations were generated using data derived from a collection of 2270 strong-motion records from 30 worldwide earthquakes. The regression equations predict Newmark displacement in terms of (1) critical acceleration ratio, (2) critical acceleration ratio and earthquake magnitude, (3) Arias intensity and critical acceleration, and (4) Arias intensity and critical acceleration ratio. These equations are well constrained and fit the data well (71% < R2 < 88%), but they have standard deviations of about 0.5 log units, such that the range defined by the mean ?? one standard deviation spans about an order of magnitude. These regression models, therefore, are not recommended for use in site-specific design, but rather for regional-scale seismic landslide hazard mapping or for rapid preliminary screening of sites. ?? 2007 Elsevier B.V. All rights reserved.

  2. Dissociation and displacement: where goes the "ouch?".

    PubMed

    Watkins, J G; Watkins, H H

    1990-07-01

    Hypnosis is widely used to relieve pain. Current theory emphasizes its dissociative features. Multiple personality patients can eliminate pain in the primary personality by displacing it into underlying alters. The Hilgards demonstrated that normal hypnotized subjects can similarly dissociate pain into a covert cognitive structural system which they called the "hidden observer." The Watkins discovered that "hidden observers" appeared to be the same phenomenon as "ego states." "Ego-state theory" assumes that human personality develops through integration and differentiation. At one end of the continuum, "differentiation" is adaptive. Ego states possess relatively permeable boundaries as in normal moods. At the other end ego-state boundaries become less permeable. Normal "differentiation" becomes maladaptive "dissociation" and multiple personalities may be created. In the intermediate range of the differentiation/dissociation continuum, "covert" ego states can be found in many normal subjects who volunteer for hypnotic laboratory experiments. Normal individuals, like multiple personalities and "hidden observer" subjects, can displace (dissociate) pain into "covert" ego states. The pain is not eliminated. This suggests that when we remove pain by hypnosis we may not be getting away "scot-free." PMID:2220652

  3. Transient digitizer with displacement current samplers

    DOEpatents

    McEwan, Thomas E. (Livermore, CA)

    1996-01-01

    A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board.

  4. Dynamic response of electromagnetic spatial displacement trackers.

    PubMed

    Adelstein, B D; Johnston, E R; Ellis, S R

    1996-01-01

    Overall system latency--the elapsed time from input human motion until the immediate consequences of that input are available in the display--is one of the most frequently cited shortcoming of current virtual environment (VE) technology. Given that spatial displacement trackers are employed to monitor head and hand position and orientation in many VE applications, the dynamic response intrinsic to these devices is an unavoidable contributor to overall system latency. In this paper, we describe a testbed and method for measurement of tracker dynamic response that use a motorized rotary swing arm to sinusoidally displace the VE sensor at a number of frequencies spanning the bandwidth of volitional human movement. During the tests, actual swing arm angle and VE sensor reports are collected and time stamped. By calibrating the time stamping technique, the tracker's internal transduction and processing time are separated from data transfer and host computer software execution latencies. We have used this test-bed to examine several VE sensors--most recently to compare latency, gain, and noise characteristics of two commercially available electromagnetic trackers: Ascension Technology Corp.'s Flock of Birds(TM) and Polhemus Inc.'s Fastrak(TM). PMID:11540397

  5. Transient digitizer with displacement current samplers

    DOEpatents

    McEwan, T.E.

    1996-05-21

    A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board. 16 figs.

  6. An interferometric strain-displacement measurement system

    NASA Technical Reports Server (NTRS)

    Sharpe, William N., Jr.

    1989-01-01

    A system for measuring the relative in-plane displacement over a gage length as short as 100 micrometers is described. Two closely spaced indentations are placed in a reflective specimen surface with a Vickers microhardness tester. Interference fringes are generated when they are illuminated with a He-Ne laser. As the distance between the indentations expands or contracts with applied load, the fringes move. This motion is monitored with a minicomputer-controlled system using linear diode arrays as sensors. Characteristics of the system are: (1) gage length ranging from 50 to 500 micrometers, but 100 micrometers is typical; (2) least-count resolution of approximately 0.0025 micrometer; and (3) sampling rate of 13 points per second. In addition, the measurement technique is non-contacting and non-reinforcing. It is useful for strain measurements over small gage lengths and for crack opening displacement measurements near crack tips. This report is a detailed description of a new system recently installed in the Mechanisms of Materials Branch at the NASA Langley Research Center. The intent is to enable a prospective user to evaluate the applicability of the system to a particular problem and assemble one if needed.

  7. Secondary atomization

    Microsoft Academic Search

    D. R. Guildenbecher; C. López-Rivera; P. E. Sojka

    2009-01-01

    When a drop is subjected to a surrounding dispersed phase that is moving at an initial relative velocity, aerodynamic forces\\u000a will cause it to deform and fragment. This is referred to as secondary atomization. In this paper, the abundant literature\\u000a on secondary atomization experimental methods, breakup morphology, breakup times, fragment size and velocity distributions,\\u000a and modeling efforts is reviewed and

  8. Experiments in cold atom optics towards precision atom interferometry

    NASA Astrophysics Data System (ADS)

    Aveline, David C.

    Atom optics has been a highly active field of research with many scientific breakthroughs over the past two decades, largely due to successful advances in laser technology, microfabrication techniques, and the development of laser cooling and trapping of neutral atoms. This dissertation details several atom optics experiments with the motivation to develop tools and techniques for precision atom wave interferometry. It provides background information about atom optics and the fundamentals behind laser cooling and trapping, including basic techniques for cold gas thermometry and absorptive detection of atoms. A brief overview of magnetic trapping and guiding in tight wire-based traps is also provided before the experimental details are presented. We developed a novel laser source of 780 nm light using frequency-doubled 1560 nm fiber amplifier. This laser system provided up to a Watt of tunable frequency stabilized light for two Rb laser cooling and trapping experiments. One system generates Bose-Einstein condensates in an optical trap while the second is based on atom chip magnetic traps. The atom chip system, detailed in this thesis, was designed and built to develop the tools necessary for transport and loading large numbers of cold atoms and explore the potential for guided atom interferometry. Techniques and results from this experiment are presented, including an efficient magnetic transport and loading method to deliver cold atom to atom chip traps. We also developed a modeling tool for the magnetic fields formed by coiled wire geometries, as well as planar wire patterns. These models helped us design traps and determine adiabatic transportation of cold atoms between macro-scale traps and micro-traps formed on atom chips. Having achieved near unity transfer efficiency, we demonstrated that this approach promises to be a consistent method for loading large numbers of atoms into micro-traps. Furthermore, we discuss an in situ imaging technique to investigate magnetic field contours of the traps and the dynamics of atoms within those confining potentials. We also controlled the propagation along the atom chip guides by accelerating atoms with longitudinal magnetic gradients, and investigated an atom focusing scheme. While the atom chip wire guides perform a role analogous to optical fibers guiding light waves, "free space" cold atoms offer great opportunity for precision interferometry. We describe a second on-going atom optics experiment that measures gravity gradients using a pair of atom fountain interferometers separated by one meter. We have demonstrated Gravity Gradiometer resolution down to 4x10-9 g/m using a 40 kg test mass. The atomic physics subsystem is described in detail, including the vacuum, cold atom source, optics, magnetic coils and shields, and vibration isolation and compensation. The system is designed to be a compact, robust, transportable instrument, taking strides towards future gravity gradient measurements in the field. In the realm of space applications, there has been interest for micro-gravity science experiments aboard the International Space Station, along with instrument development for gravity mapping of Earth and planetary bodies with satellite-based instruments. Furthermore, there are ground-based applications for gravity imaging of local density distributions, precision measurement of gravity, as well as proposals for redefining the kilogram, detecting gravitational waves and determining the Gravitational constant.

  9. Perception of Direction for Applied Tangential Skin Displacement: Effects of Speed, Displacement, and Repetition

    Microsoft Academic Search

    Brian T. Gleeson; Scott K. Horschel; William R. Provancher

    2010-01-01

    A variety of tasks could benefit from the availability of direction cues that do not rely on vision or sound. The application of tangential skin displacement at the fingertip has been found to be a reliable means of communicating direction and has potential to be rendered by a compact device. Our lab has conducted experiments exploring the use of this

  10. 26 CFR 1.9300-1 - Reduction in taxable income for housing displaced individuals.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...for providing housing to one or more Hurricane Katrina displaced individuals. For...in the case of housing provided to a Hurricane Katrina displaced individual (as defined...The term displaced individual means a Hurricane Katrina displaced individual as...

  11. 26 CFR 1.9300-1 - Reduction in taxable income for housing displaced individuals.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...for providing housing to one or more Hurricane Katrina displaced individuals. For...in the case of housing provided to a Hurricane Katrina displaced individual (as defined...The term displaced individual means a Hurricane Katrina displaced individual as...

  12. 26 CFR 1.9300-1 - Reduction in taxable income for housing displaced individuals.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...for providing housing to one or more Hurricane Katrina displaced individuals. For...in the case of housing provided to a Hurricane Katrina displaced individual (as defined...The term displaced individual means a Hurricane Katrina displaced individual as...

  13. 26 CFR 1.9300-1 - Reduction in taxable income for housing displaced individuals.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...for providing housing to one or more Hurricane Katrina displaced individuals. For...in the case of housing provided to a Hurricane Katrina displaced individual (as defined...The term displaced individual means a Hurricane Katrina displaced individual as...

  14. 26 CFR 1.9300-1 - Reduction in taxable income for housing displaced individuals.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...for providing housing to one or more Hurricane Katrina displaced individuals. For...in the case of housing provided to a Hurricane Katrina displaced individual (as defined...The term displaced individual means a Hurricane Katrina displaced individual as...

  15. Prismatic displacement effect of progressive multifocal glasses on reaction time and accuracy in elderly people

    PubMed Central

    Ellison, Ashton C; Campbell, A John; Robertson, M Clare; Sanderson, Gordon F

    2014-01-01

    Background Multifocal glasses (bifocals, trifocals, and progressives) increase the risk of falling in elderly people, but how they do so is unclear. To explain why glasses with progressive addition lenses increase the risk of falls and whether this can be attributed to false projection, this study aimed to 1) map the prismatic displacement of a progressive lens, and 2) test whether this displacement impaired reaction time and accuracy. Methods The reaction times of healthy ?75-year-olds (31 participants) were measured when grasping for a bar and touching a black line. Participants performed each test twice, wearing their progressives and new, matched single vision (distance) glasses in random order. The line and bar targets were positioned according to the maximum and minimum prismatic displacement effect through the progressive lens, mapped using a focimeter. Results Progressive spectacle lenses have large areas of prismatic displacement in the central visual axis and edges. Reaction time was faster for progressives compared with single vision glasses with a centrally-placed horizontal grab bar (mean difference 101 ms, P=0.011 [repeated measures analysis]) and a horizontal black line placed 300 mm below center (mean difference 80 ms, P=0.007). There was no difference in accuracy between the two types of glasses. Conclusion Older people appear to adapt to the false projection of progressives in the central visual axis. This adaptation means that swapping to new glasses or a large change in prescription may lead to a fall. Frequently updating glasses may be more beneficial. PMID:24872674

  16. Energy storage possibilities of atomic hydrogen

    NASA Technical Reports Server (NTRS)

    Etters, R. D.; Dugan, J. V., Jr.; Palmer, R.

    1976-01-01

    The possibility of storing large amounts of energy in a free radical system such as atomic hydrogen is analyzed. Attention is focused on theoretical calculations of the ground state properties of spin-aligned atomic triplet hydrogen, deuterium, and tritium. The solid-liquid phase transition in atomic hydrogen is also examined.

  17. Automatic Alignment of Displacement-Measuring Interferometer

    NASA Technical Reports Server (NTRS)

    Halverson, Peter; Regehr, Martin; Spero, Robert; Alvarez-Salazar, Oscar; Loya, Frank; Logan, Jennifer

    2006-01-01

    A control system strives to maintain the correct alignment of a laser beam in an interferometer dedicated to measuring the displacement or distance between two fiducial corner-cube reflectors. The correct alignment of the laser beam is parallel to the line between the corner points of the corner-cube reflectors: Any deviation from parallelism changes the length of the optical path between the reflectors, thereby introducing a displacement or distance measurement error. On the basis of the geometrical optics of corner-cube reflectors, the length of the optical path can be shown to be L = L(sub 0)cos theta, where L(sub 0) is the distance between the corner points and theta is the misalignment angle. Therefore, the measurement error is given by DeltaL = L(sub 0)(cos theta - 1). In the usual case in which the misalignment is small, this error can be approximated as DeltaL approximately equal to -L(sub 0)theta sup 2/2. The control system (see figure) is implemented partly in hardware and partly in software. The control system includes three piezoelectric actuators for rapid, fine adjustment of the direction of the laser beam. The voltages applied to the piezoelectric actuators include components designed to scan the beam in a circular pattern so that the beam traces out a narrow cone (60 microradians wide in the initial application) about the direction in which it is nominally aimed. This scan is performed at a frequency (2.5 Hz in the initial application) well below the resonance frequency of any vibration of the interferometer. The laser beam makes a round trip to both corner-cube reflectors and then interferes with the launched beam. The interference is detected on a photodiode. The length of the optical path is measured by a heterodyne technique: A 100- kHz frequency shift between the launched beam and a reference beam imposes, on the detected signal, an interferometric phase shift proportional to the length of the optical path. A phase meter comprising analog filters and specialized digital circuitry converts the phase shift to an indication of displacement, generating a digital signal proportional to the path length.

  18. Simulation of secondary fault shear displacements - method and application

    NASA Astrophysics Data System (ADS)

    Fälth, Billy; Hökmark, Harald; Lund, Björn; Mai, P. Martin; Munier, Raymond

    2014-05-01

    We present an earthquake simulation method to calculate dynamically and statically induced shear displacements on faults near a large earthquake. Our results are aimed at improved safety assessment of underground waste storage facilities, e.g. a nuclear waste repository. For our simulations, we use the distinct element code 3DEC. We benchmark 3DEC by running an earthquake simulation and then compare the displacement waveforms at a number of surface receivers with the corresponding results obtained from the COMPSYN code package. The benchmark test shows a good agreement in terms of both phase and amplitude. In our application to a potential earthquake near a storage facility, we use a model with a pre-defined earthquake fault plane (primary fault) surrounded by numerous smaller discontinuities (target fractures) representing faults in which shear movements may be induced by the earthquake. The primary fault and the target fractures are embedded in an elastic medium. Initial stresses are applied and the fault rupture mechanism is simulated through a programmed reduction of the primary fault shear strength, which is initiated at a pre-defined hypocenter. The rupture is propagated at a typical rupture propagation speed and arrested when it reaches the fault plane boundaries. The primary fault residual strength properties are uniform over the fault plane. The method allows for calculation of target fracture shear movements induced by static stress redistribution as well as by dynamic effects. We apply the earthquake simulation method in a model of the Forsmark nuclear waste repository site in Sweden with rock mass properties, in situ stresses and fault geometries according to the description of the site established by the Swedish Nuclear Fuel and Waste Management Co (SKB). The target fracture orientations are based on the Discrete Fracture Network model developed for the site. With parameter values set to provide reasonable upper bound estimates of target fracture displacements, the model generates primary fault slip and slip velocities that are both high compared to those found in real earthquakes. The calculated target fracture movements reach some tens of millimetres on 300 m diameter fractures. We also present results indicating the sensitivity of primary fault slip and target fracture movements to e.g. variation of primary fault residual strength, change of hypocenter location and variations in the initial stress field.

  19. A capacitive transducer for monitoring tridimensional submicrometric displacements

    NASA Astrophysics Data System (ADS)

    Cabiati, Franco; Giaretto, Valter; Miraldi, Elio

    2000-04-01

    A new three-in-one capacitive transducer that operates with three transformer bridges at separate frequencies is here described. Three plane capacitors result from the placing of a triangular right pyramid (the moveable element, being fixed to the point to be monitored) to face a reentrant right triangular pyramid which was carved into one of the bases of a triangular prism (the fixed element). Three out-of-balance signals result when the moveable element moves from the zero position, where each variable capacitance equals the corresponding reference one. The three differences between the currents that flow through each series of capacitances are summed up in one shielded output cable. One transconductance preamplifier converts the current signals into three superimposed voltage signals. By selecting the reference frequency to be sent to a lock-in amplifier, one can monitor the movement of the selected face of the moveable element, that is, by choosing one of the three bridge frequencies in sequence one obtains the three Cartesian components of the vectorial displacement that the moveable element has undergone. The use of glass-ceramic material with a negligible thermal expansion coefficient and the integration of reference capacitors in the body of the transducer, allow this transducer to operate within fairly large ranges of temperature and humidity. The use of a current detector with low input impedance allows this transducer to be connected to the bridges and to the preamplifier with some meters of coaxial cables, without any appreciable effects on the sensitivity. The various noise and uncertainty sources are also here discussed. A ?40 nm uncertainty with displacements in the ±12 ?m range has been obtained in a thermal test that was carried out using four transducers applied to a cylindrical aluminum sample.

  20. Connecting localized DNA strand displacement reactions.

    PubMed

    Mullor Ruiz, Ismael; Arbona, Jean-Michel; Lad, Amitkumar; Mendoza, Oscar; Aimé, Jean-Pierre; Elezgaray, Juan

    2015-07-23

    Logic circuits based on DNA strand displacement reactions have been shown to be versatile enough to compute the square root of four-bit numbers. The implementation of these circuits as a set of bulk reactions faces difficulties which include leaky reactions and intrinsically slow, diffusion-limited reaction rates. In this paper, we consider simple examples of these circuits when they are attached to platforms (DNA origamis). As expected, constraining distances between DNA strands leads to faster reaction rates. However, it also induces side-effects that are not detectable in the solution-phase version of this circuitry. Appropriate design of the system, including protection and asymmetry between input and fuel strands, leads to a reproducible behaviour, at least one order of magnitude faster than the one observed under bulk conditions. PMID:26168352

  1. Position Displacement of Diffuse Interstellar Bands

    NASA Astrophysics Data System (ADS)

    Galazutdinov, G.; Kre?owski, J.; Beletsky, Y.; Valyavin, G.

    2015-04-01

    We reconsider the already published phenomenon of the blue shift of diffuse interstellar bands, observed in spectra of HD34078 (AE Aur) and members of the Sco OB1 association, in particular HD152233. We have analyzed 29 diffuse bands. Some of them, already proven as blue-shifted in our earlier study, are now confirmed using another instrument: the 6.5 m Clay telescope equipped with the MIKE spectrograph. The high signal-to-noise ratio (over 600) of our spectra allowed us to reveal even small small-scale displacements of positions (both blue and redshifts) of diffuse bands along the considered lines of sight. In some cases, the magnitude of deviation exceeds 10 km s-1. Also, we prove that profiles of many diffuse bands in spectra of HD34078 suffer significant broadening. The origin of the observed phenomena is discussed.

  2. Optical inverse-square displacement sensor

    DOEpatents

    Howe, Robert D. (San Mateo County, CA); Kychakoff, George (King County, WA)

    1989-01-01

    This invention comprises an optical displacement sensor that uses the inverse-square attenuation of light reflected from a diffused surface to calculate the distance from the sensor to the reflecting surface. Light emerging from an optical fiber or the like is directed onto the surface whose distance is to be measured. The intensity I of reflected light is angle dependent, but within a sufficiently small solid angle it falls off as the inverse square of the distance from the surface. At least a pair of optical detectors are mounted to detect the reflected light within the small solid angle, their ends being at different distances R and R+.DELTA.R from the surface. The distance R can then be found in terms of the ratio of the intensity measurements and the separation length as ##EQU1##

  3. Optical inverse-square displacement sensor

    DOEpatents

    Howe, R.D.; Kychakoff, G.

    1989-09-12

    This invention comprises an optical displacement sensor that uses the inverse-square attenuation of light reflected from a diffused surface to calculate the distance from the sensor to the reflecting surface. Light emerging from an optical fiber or the like is directed onto the surface whose distance is to be measured. The intensity I of reflected light is angle dependent, but within a sufficiently small solid angle it falls off as the inverse square of the distance from the surface. At least a pair of optical detectors are mounted to detect the reflected light within the small solid angle, their ends being at different distances R and R + [Delta]R from the surface. The distance R can then be found in terms of the ratio of the intensity measurements and the separation length as given in an equation. 10 figs.

  4. Some comments on particle image displacement velocimetry

    NASA Technical Reports Server (NTRS)

    Lourenco, L. M.

    1988-01-01

    Laser speckle velocimetry (LSV) or particle image displacement velocimetry, is introduced. This technique provides the simultaneous visualization of the two-dimensional streamline pattern in unsteady flows as well as the quantification of the velocity field over an entire plane. The advantage of this technique is that the velocity field can be measured over an entire plane of the flow field simultaneously, with accuracy and spatial resolution. From this the instantaneous vorticity field can be easily obtained. This constitutes a great asset for the study of a variety of flows that evolve stochastically in both space and time. The basic concept of LSV; methods of data acquisition and reduction, examples of its use, and parameters that affect its utilization are described.

  5. Intrinsic mean-square displacements in proteins

    NASA Astrophysics Data System (ADS)

    Vural, Derya; Glyde, Henry R.

    2012-07-01

    The thermal mean-square displacement (MSD) of hydrogen in proteins and its associated hydration water is measured by neutron scattering experiments and used an indicator of protein function. The observed MSD as currently determined depends on the energy resolution width of the neutron scattering instrument employed. We propose a method for obtaining the intrinsic MSD of H in the proteins, one that is independent of the instrument resolution width. The intrinsic MSD is defined as the infinite time value of that appears in the Debye-Waller factor. The method consists of fitting a model to the resolution broadened elastic incoherent structure factor or to the resolution dependent MSD. The model contains the intrinsic MSD, the instrument resolution width, and a rate constant characterizing the motions of H in the protein. The method is illustrated by obtaining the intrinsic MSD of heparan sulphate (HS-0.4), ribonuclease A, and staphysloccal nuclase (SNase) from data in the literature.

  6. DNA strand displacement system running logic programs.

    PubMed

    Rodríguez-Patón, Alfonso; Sainz de Murieta, Iñaki; Sosík, Petr

    2014-01-01

    The paper presents a DNA-based computing model which is enzyme-free and autonomous, not requiring a human intervention during the computation. The model is able to perform iterated resolution steps with logical formulae in conjunctive normal form. The implementation is based on the technique of DNA strand displacement, with each clause encoded in a separate DNA molecule. Propositions are encoded assigning a strand to each proposition p, and its complementary strand to the proposition ¬p; clauses are encoded comprising different propositions in the same strand. The model allows to run logic programs composed of Horn clauses by cascading resolution steps. The potential of the model is demonstrated also by its theoretical capability of solving SAT. The resulting SAT algorithm has a linear time complexity in the number of resolution steps, whereas its spatial complexity is exponential in the number of variables of the formula. PMID:24211259

  7. Relativistic Lagrangian displacement field and tensor perturbations

    E-print Network

    Cornelius Rampf; Alexander Wiegand

    2014-12-14

    We investigate the purely spatial Lagrangian coordinate transformation from the Lagrangian to the basic Eulerian frame. We demonstrate three techniques for extracting the relativistic displacement field from a given solution in the Lagrangian frame. These techniques are (a) from defining a local set of Eulerian coordinates embedded into the Lagrangian frame; (b) from performing a specific gauge transformation; and (c) from a fully non-perturbative approach based on the ADM split. The latter approach shows that this decomposition is not tied to a specific perturbative formulation for the solution of the Einstein equations. Rather, it can be defined at the level of the non-perturbative coordinate change from the Lagrangian to the Eulerian description. Studying such different techniques is useful because it allows us to compare and develop further the various approximation techniques available in the Lagrangian formulation. We find that one has to solve the gravitational wave equation in the relativistic analysis, otherwise the corresponding Newtonian limit will necessarily contain spurious non-propagating tensor artefacts at second order in the Eulerian frame. We also derive the magnetic part of the Weyl tensor in the Lagrangian frame, and find that it is not only excited by gravitational waves but also by tensor perturbations which are induced through the non-linear frame-dragging. We apply our findings to calculate for the first time the relativistic displacement field, up to second order, for a $\\Lambda$CDM Universe in the presence of a local primordial non-Gaussian component. Finally, we also comment on recent claims about whether mass conservation in the Lagrangian frame is violated.

  8. An Experimental Microvisual Investigation of Viscously Unstable Displacements Relevant to Geological Sequestration

    NASA Astrophysics Data System (ADS)

    Buchgraber, M.; Kovscek, A. R.

    2012-12-01

    The storage of captured carbon dioxide in saline aquifers has been identified as a very promising method due to the large storage capacities and significant number of available storage sites. Although the subsurface flow of immiscible fluids has been investigated in the oil and gas industry, the characteristics of the water-CO2 fluid pair that leads to highly unstable fluid fronts is still not fully understood. So far, most modeling of storage in aquifers relies on the linear displacement theory of Buckley and Leveret. In this work, the results of two-phase laboratory displacements in transparent micromodels are reported. Experiments employ a range of mobility ratios from 0.3 to 980 and capillary numbers from 2.5×10-4 to 2.8×10-8. This range spans the parameter space of interest to sequestration. The porous media are etched silicon micromodels with Berea sandstone-like pore structures and geometry. Displacement fronts of stable and unstable drainage processes are reported and analyzed. Flow is visualized directly at the scale of the whole 5 cm by 5 cm micromodel as well as at pore-level using a reflected light microscope. Drainage results showed that there was an increase in finger number and finger size as capillary number increased for a given mobility ratio. That is, displacements showed more unstable features at large capillary number. Capillary number did not influence areal sweep efficiency, but showed significant effects on the pore level. Low capillary numbers led to greater snap off and small pores were left undrained whereas high capillary number displacements showed sweep out of both small and large pore structures leaving less wetting saturation behind. Image analysis techniques were used to evaluate the unstable displacement fronts. Results indicate that saturation does not scale with time (i.e. wave speed) and the displacement pattern follows a fractal pattern. Results obtained are also relevant to the CO2 water alternating gas process. Front stabilities at macro scale for different mobility ratios and capillary numbers

  9. Atom Interferometry

    ScienceCinema

    Mark Kasevich

    2010-01-08

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton?s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  10. Atom Interferometry

    SciTech Connect

    Mark Kasevich

    2008-05-07

    Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton’s constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gryoscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be sued to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

  11. Cenozoic evidence of displacements along the Meers Fault, southwestern Oklahoma 

    E-print Network

    Kientop, Gregory Allen

    1988-01-01

    -lateral movement (and possibly as many as four) was established near the Bedrock Pit Site. In addition, small (young) drainages are offset vert1cally due to the later Holocene displacements. Brittle deformation was associated with th1s earlier displacement(s... of the Proposed Study Geologic Setting. . . . . . . Physiographic Setting The Meers Fault Study Area . METHODOLOGY Remote Sensing . Pediment Investigation . Wichita Mountains Study Alluvial Fan Excavation Pointer Site Excavation Bedrock Pit Site . Cave...

  12. Finite displacements of points, planes, and lines via screw theory

    Microsoft Academic Search

    I. A. Parkin

    1995-01-01

    Geometrical elements, namely point, directed plane, and directed line, are here taken in isolation from any rigid body to which they may belong. The available finite screws are fully determined for a general finite displacement of each element. Each screw carries a quasi-pitch, or “quatch”, that reduces to the commonly-accepted pitch when a displacement becomes infinitesimal. Each element-displacement has its

  13. Quantifying dithiothreitol displacement of functional ligands from gold nanoparticles.

    PubMed

    Tsai, De-Hao; Shelton, Melanie P; DelRio, Frank W; Elzey, Sherrie; Guha, Suvajyoti; Zachariah, Michael R; Hackley, Vincent A

    2012-12-01

    Dithiothreitol (DTT)-based displacement is widely utilized for separating ligands from their gold nanoparticle (AuNP) conjugates, a critical step for differentiating and quantifying surface-bound functional ligands and therefore the effective surface density of these species on nanoparticle-based therapeutics and other functional constructs. The underlying assumption is that DTT is smaller and much more reactive toward gold compared with most ligands of interest, and as a result will reactively displace the ligands from surface sites thereby enabling their quantification. In this study, we use complementary dimensional and spectroscopic methods to characterize the efficiency of DTT displacement. Thiolated methoxypolyethylene glycol (SH-PEG) and bovine serum albumin (BSA) were chosen as representative ligands. Results clearly show that (1) DTT does not completely displace bound SH-PEG or BSA from AuNPs, and (2) the displacement efficiency is dependent on the binding affinity between the ligands and the AuNP surface. Additionally, the displacement efficiency for conjugated SH-PEG is moderately dependent on the molecular mass (yielding efficiencies ranging from 60 to 80% measured by ATR-FTIR and ?90% by ES-DMA), indicating that the displacement efficiency for SH-PEG is predominantly determined by the S-Au bond. BSA is particularly difficult to displace with DTT (i.e., the displacement efficiency is nearly zero) when it is in the so-called normal form. The displacement efficiency for BSA improves to 80% when it undergoes a conformational change to the expanded form through a process of pH change or treatment with a surfactant. An analysis of the three-component system (SH-PEG + BSA + AuNP) indicates that the presence of SH-PEG decreases the displacement efficiency for BSA, whereas the displacement efficiency for SH-PEG is less impacted by the presence of BSA. PMID:23104310

  14. Unrecognised displacement of mandibular molar root into the submandibular space.

    PubMed

    Nusrath, M A; Banks, R J

    2010-09-25

    We describe a case of swelling in the right submandibular and sublingual space caused by displacement of a lower second molar root in the submandibular space. This displacement was not recognised at the time of extraction. The techniques used to minimise the risk of accidental displacement of teeth and roots, during extraction are discussed. The importance of recognising this complication and methods of retrieval are highlighted. PMID:20871549

  15. Displacement chromatography of proteins on hydrophobic charge induction adsorbent column

    Microsoft Academic Search

    Guofeng Zhao; Yan Sun

    2007-01-01

    Displacement chromatography of protein mixtures is proposed on hydrophobic charge induction chromatography (HCIC). We have used an HCIC medium, MEP-Hypercel as the stationary phase and a quaternary ammonium salt, benzethonium chloride, as the displacer. It was found that the multiple interactions between proteins\\/displacer and the HCIC sorbent, i.e. hydrophobic interaction and charge repulsion, enabled a greater flexibility for the design

  16. Conditional preparation of arbitrary atomic Dicke states

    E-print Network

    Karel Lemr; Jaromir Fiurasek

    2008-12-02

    We propose an experimentally accessible procedure for conditional preparation of highly non-classical states of collective spin of an atomic ensemble. The quantum state engineering is based on a combination of QND interaction between atoms and light previously prepared in a non-Gaussian state using photon subtraction from squeezed vacuum beam, homodyne detection on the output light beam, and a coherent displacement of atomic state. The procedure is capable of non-deterministic preparation of a wide class of superpositions of atomic Dicke states. We present several techniques to optimize the performance of the protocol and maximize the trade-off between fidelity of prepared state and success probability of the scheme.

  17. Atomic Zitterbewegung in Abelian vector gauge potentials

    SciTech Connect

    Song, J.-J.; Foreman, Bradley A. [Department of Physics, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China)

    2009-10-15

    We propose a scheme to realize Zitterbewegung (ZB) with cold atoms in an Abelian vector potential. Two dark states can be created by interacting alkali-metal atoms with three coaxial Gaussian beams. Atoms moving in the subspace spanned by the two dark states feel a vector gauge potential that is nonvanishing only along the laser axis. We show that cold atoms in this Abelian vector potential undergo ZB with a large amplitude detectable in experiment.

  18. Nonstatistical fragmentation of large molecules

    NASA Astrophysics Data System (ADS)

    Stockett, M. H.; Zettergren, H.; Adoui, L.; Alexander, J. D.; BÄ`rzi?š, U.; Chen, T.; Gatchell, M.; Haag, N.; Huber, B. A.; Hvelplund, P.; Johansson, A.; Johansson, H. A. B.; Kulyk, K.; Rosén, S.; Rousseau, P.; Støchkel, K.; Schmidt, H. T.; Cederquist, H.

    2014-03-01

    We present experimental evidence for the dominance of prompt single-atom knockout in fragmenting collisions between large polycyclic aromatic hydrocarbon cations and He atoms at center-of-mass energies close to 100 eV. Such nonstatistical processes are shown to give highly reactive fragments. We argue that nonstatistical fragmentation is dominant for any sufficiently large molecular system under similar conditions.

  19. Molecular dynamics simulation of threshold displacement energies in zircon

    SciTech Connect

    Moreira, Pedro A.; Devanathan, Ramaswami; Yu, Jianguo; Weber, William J.

    2009-10-15

    Molecular-dynamics simulations were used to examine the displacement threshold energy (Ed) surface for Zr, Si and O in zircon using two different interatomic potentials. For each sublattice, the simulation was repeated from different initial conditions to estimate the uncertainty in the calculated value of Ed. The displacement threshold energies vary considerably with crystallographic direction and sublattice. The average displacement energy calculated with a recently developed transferable potential is about 120 and 60 eV for cations and anions, respectively. The oxygen displacement energy shows good agreement with experimental estimates in ceramics.

  20. GNSS-derived Coseismic Displacement of the Gökçeada Earthquake (2014, Mw:6.9) based on 1 Hz GNSS Data

    NASA Astrophysics Data System (ADS)

    Özer Yi?it, Cemal; Tiryakio?lu, Ibrahim; Halis Saka, M.; Metin Alkan, Reha

    2015-04-01

    GNSS technology has been extensively used to measure crustal deformation and widely used to construct displacement waveforms. GNSS seismology uses GNSS receiver as displacement seismometer for earthquake studies. In other words, it can sense large dynamic displacement without saturation. In GNSS, relative positioning method requires a reference station with no-motion whereas Precise Point Positioning (PPP) method does not need any reference station. However, PPP method, unlike relative positioning method, requires readily precise GNSS satellite orbit and clock product calculated beforehand to perform absolute positioning using a single GNSS receiver data. In case of large earthquake, it may be crucial to select stable reference for relative positioning. Therefore, in order to monitor ground motion pattern caused by the earthquake, PPP method is advantageous because it provides absolute coseismic displacements with respect to a global reference frame. In this study, we investigate the pattern of coseismic displacement and velocity of the Gokceada (Turkey) earthquake (United States Geological Survey M=6.9, May 24, 2014 - 09:25:02 UTC). One hertz of 8 continuous GNSS stations, part of CORS-TR network, were processed using PPP and relative positioning techniques to estimate epoch-by-epoch positions of the sites. The epicenter distance of GNSS stations are ranging from 90 km to 250 km. CSRS-PPP and GAMIT-Track tool software were used for PPP and relative positioning solution, respectively. We analyze the ground motion characteristic of GNSS-derived displacement and velocity. Results show that the travelling time of earthquake wave for each station increased with respect to epicentral distance. Results also demonstrate that the shaking amplitude generated by the earthquake decreased while epicentral distance increased. Peak to peak displacement of the closest station to epicenter is around 10 cm and 5 cm for north and east component, respectively. For selected farthest site, peak to peak displacement is around 5 cm and 3 cm for north and east component, respectively. Arrival time difference of earthquake wave between closest and farthest sites used in this study is around 50 sec. In this paper, we also compare PPP-based displacement/velocity to relative positioning-based displacement/velocity. The result demonstrated that the PPP based solutions shows good agreement with that of the relative positioning solutions in terms of the ability to capture coseismic displacement.

  1. Atom Optics Quantum Pendulum

    E-print Network

    Muhammad Ayub; Khalid Naseer; Manzoor Ali; Farhan Saif

    2010-12-29

    We explain the dynamics of cold atoms, initially trapped and cooled in a magneto-optic trap, in a monochromatic stationary standing electromagnetic wave field. In the large detuning limit the system is modeled as a nonlinear quantum pendulum. We show that wave packet evolution of the quantum particle probes parametric regimes in the quantum pendulum which support classical period, quantum mechanical revival and super revival phenomena. Interestingly, complete reconstruction in particular parametric regime at quantum revival times is independent of potential height.

  2. Inertial forces affect fluid front displacement dynamics in a pore-throat network model

    NASA Astrophysics Data System (ADS)

    Moebius, Franziska; Or, Dani

    2014-08-01

    The seemingly regular and continuous motion of fluid displacement fronts in porous media at the macroscopic scale is propelled by numerous (largely invisible) pore-scale abrupt interfacial jumps and pressure bursts. Fluid fronts in porous media are characterized by sharp phase discontinuities and by rapid pore-scale dynamics that underlie their motion; both attributes challenge standard continuum theories of these flow processes. Moreover, details of pore-scale dynamics affect front morphology and subsequent phase entrapment behind a front and thereby shape key macroscopic transport properties of the unsaturated zone. The study presents a pore-throat network model that focuses on quantifying interfacial dynamics and interactions along fluid displacement fronts. The porous medium is represented by a lattice of connected pore throats capable of detaining menisci and giving rise to fluid-fluid interfacial jumps (the study focuses on flow rate controlled drainage). For each meniscus along the displacement front we formulate a local inertial, capillary, viscous, and hydrostatic force balance that is then solved simultaneously for the entire front. The model enables systematic evaluation of the role of inertia and boundary conditions. Results show that while displacement patterns are affected by inertial forces mainly by invasion of throats with higher capillary resistance, phase entrapment (residual saturation) is largely unaffected by inertia, limiting inertial effects on hydrological properties behind a front. Interfacial jump velocities are often an order of magnitude larger than mean front velocity, are strongly dependent on geometrical throat dimensions, and become less predictable (more scattered) when inertia is considered. Model simulations of the distributions of capillary pressure fluctuations and waiting times between invasion events follow an exponential distribution and are in good agreement with experimental results. The modeling approach provides insights into the rich pore-scale dynamics of displacement fronts; these insights not only improve the basic understanding of these ubiquitous processes, but could shed light on solute dispersion and colloids mobilization at fronts and the mechanical consequences of passing fronts.

  3. Imaging screw dislocations at atomic resolution by aberration-corrected electron optical sectioning

    PubMed Central

    Yang, H.; Lozano, J. G.; Pennycook, T. J.; Jones, L.; Hirsch, P. B.; Nellist, P. D.

    2015-01-01

    Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced parallel to the dislocation line, and therefore the screw displacements are parallel to the electron beam and become invisible when viewed end-on. Here we show that screw displacements can be imaged directly with the dislocation lying in a plane transverse to the electron beam by optical sectioning using annular dark field imaging in a scanning transmission electron microscope. Applying this technique to a mixed [a+c] dislocation in GaN allows direct imaging of a screw dissociation with a 1.65-nm dissociation distance, thereby demonstrating a new method for characterizing dislocation core structures. PMID:26041257

  4. Imaging screw dislocations at atomic resolution by aberration-corrected electron optical sectioning.

    PubMed

    Yang, H; Lozano, J G; Pennycook, T J; Jones, L; Hirsch, P B; Nellist, P D

    2015-01-01

    Screw dislocations play an important role in materials' mechanical, electrical and optical properties. However, imaging the atomic displacements in screw dislocations remains challenging. Although advanced electron microscopy techniques have allowed atomic-scale characterization of edge dislocations from the conventional end-on view, for screw dislocations, the atoms are predominantly displaced parallel to the dislocation line, and therefore the screw displacements are parallel to the electron beam and become invisible when viewed end-on. Here we show that screw displacements can be imaged directly with the dislocation lying in a plane transverse to the electron beam by optical sectioning using annular dark field imaging in a scanning transmission electron microscope. Applying this technique to a mixed [a+c] dislocation in GaN allows direct imaging of a screw dissociation with a 1.65-nm dissociation distance, thereby demonstrating a new method for characterizing dislocation core structures. PMID:26041257

  5. Similarity of atoms in molecules

    SciTech Connect

    Cioslowski, J.; Nanayakkara, A. (Florida State Univ., Tallahassee, FL (United States))

    1993-12-01

    Similarity of atoms in molecules is quantitatively assessed with a measure that employs electron densities within respective atomic basins. This atomic similarity measure does not rely on arbitrary assumptions concerning basis functions or 'atomic orbitals', is relatively inexpensive to compute, and has straightforward interpretation. Inspection of similarities between pairs of carbon, hydrogen, and fluorine atoms in the CH[sub 4], CH[sub 3]F, CH[sub 2]F[sub 2], CHF[sub 3], CF[sub 4], C[sub 2]H[sub 2], C[sub 2]H[sub 4], and C[sub 2]H[sub 6] molecules, calculated at the MP2/6-311G[sup **] level of theory, reveals that the atomic similarity is greatly reduced by a change in the number or the character of ligands (i.e. the atoms with nuclei linked through bond paths to the nucleus of the atom in question). On the other hand, atoms with formally identical (i.e. having the same nuclei and numbers of ligands) ligands resemble each other to a large degree, with the similarity indices greater than 0.95 for hydrogens and 0.99 for non-hydrogens. 19 refs., 6 tabs.

  6. Measurement of Object Displacement Using Phase Stepped, Real-Time Holographic Interferometry.

    NASA Astrophysics Data System (ADS)

    Ovryn, Benjie

    Phase stepped holographic interferometry is a noncontact method for measuring displacements over a large field of view with a precision of about 5 nm. The whole -field capabilities and high sensitivity of this method make it potentially unrivaled for measuring spatial inhomogeneities, for example, the proposed spatial variation of the piezoelectric coefficient in cortical bone. This dissertation has advanced the capabilities of this technique for the simultaneous, whole-field measurement of two or more components of displacement (1) by providing a detailed analysis of the effect of random and systematic errors on a displacement or strain measurement; (2) by demonstrating that the Carre algorithm, with phase step angles in multiples of pi/4, provides a least squares solution to an over-determined set of phase stepped intensity measurements, minimizes the affect of random and systematic intensity and phase errors and therefore is the best choice for a phase step algorithm; (3) by offering a new method for compensating for spurious systematic drift; (4) by applying of the former method to allow temporal averaging of repeatedly acquired data sets thereby increasing signal-to-noise while maintaining full spatial resolution; (5) by developing a new test procedure for calibrating the apparatus based on displacement of a poled ceramic due to the converse piezoelectric effect and (6) by introducing a two-camera method for measuring two or more components of displacement and strain simultaneously and verifying the methodology for two dimensional displacements of a piezoelectric ceramic. The evidence indicates that this method, which can employ stereo viewing with either two or three cameras, is a promising approach for the simultaneous measurement of two or more components of displacement. The method was also applied to the measurement of displacement in two old samples of dry bovine tibia, held as cantilever beams and subjected to potentials up to 900 V, however, consistent results were not found. The null results indicate either: (1) the samples were no longer piezoelectrically active; (2) the proposed model, which stipulates that the piezoelectric coefficients vary across the bone, is incorrect and/or (3) the appropriate piezoelectric constant is less than 0.001 pm/V.

  7. Landslide displacement vectors derived from multi-temporal topographic LiDAR data

    NASA Astrophysics Data System (ADS)

    Fey, Christine; Rutzinger, Martin; Bremer, Magnus; Prager, Christoph; Zangerl, Christian

    2014-05-01

    Information about slope geometry and kinematics of landslides is essential for hazard assessment, monitoring and planning of protection and mitigation measures. Especially for remote and inaccessible slopes, subsurface data (e.g. boreholes, tunnels, investigation adits) are often not available and thus the deformation characteristics must be derived from surface displacement data. In recent years, multi-temporal topographic LiDAR (Light Detection and Ranging) data became an increasingly improved tool for detecting topographic surface deformations. In this context, LiDAR-based change detection is commonly applied for quantifying surface elevation changes. Advanced change detection methods derive displacement vectors with direction and velocities of slope movements. To extract displacement vectors from LiDAR raster data (i) an approach based on feature tracking by image correlation and (ii) an approach based on feature tracking by vectors breaklines are investigated. The image correlation method is based on the IMCORR software (National Snow and Ice Data Center, University of Colorado, Boulder), implemented in a SAGA GIS module. The image correlation algorithm is based on a normalized cross-covariance method. The algorithm searches tie points in two feature rasters derived from a digital surface model acquired at different time stamps. The method assesses automatically the displacement rates and directions of distinct terrain features e.g. displaced mountain ridges or striking boulders. In contrast the vector-based breakline methods require manual selection of tie points. The breaklines are the product of vectorized curvature raster images and extracting the "upper terrain edges" (topographic ridges) and "lower terrain edges" (topographic depressions). Both methods were tested on simulated terrain with determined displacement rates in order to quantify i) the accuracy ii) the minimum detectable movement rates iii) the influence of terrain characteristics iv) the influence of input raster cell size and v) the influence of method parameter settings. Both methods were applied to investigate the development of an active rockslide in high mountain terrain. As a result, both methods yield reasonable data in order to differentiate between landslide areas and stable terrain as well as document the kinematic development of different sub-slabs within the landslide masses (featuring different movement directions and rates). Limitations are given for areas with large displacements and complex bedrock deformation, where automatic feature-tracking lead to wrong correlation results and tie points do not coincide with real displaced features. For complex deformation mechanism only the analysis method based on breaklines and manual tie point identification is suitable for vector extraction. Automated spatial analyses of topographic LiDAR data are a fundamental support to answer a variety of morphological-geological and monitoring questions.

  8. Quantifying the Interfractional Displacement of the Gastroesophageal Junction During Radiation Therapy for Esophageal Cancer

    SciTech Connect

    Wang Jingya [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Lin, Steven H., E-mail: shlin@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Dong Lei; Balter, Peter; Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Komaki, Ritsuko; Cox, James D. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Starkschall, George [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2012-06-01

    Purpose: Accounting for interfractional changes in tumor location improves the accuracy of radiation treatment delivery. The purpose of this study was to quantify the interfractional displacement of the gastroesophageal junction (GEJ) based on standard treatment setup in patients with esophageal cancer undergoing radiation therapy. Methods and Materials: Free-breathing four-dimensional computed tomography (4D-CT) datasets were acquired weekly from 22 patients during treatment for esophageal adenocarcinoma. Scans were registered to baseline (simulation) 4D-CT scans by using bony landmarks. The distance between the center of the GEJ contour on the simulation scan and the mean location of GEJ centers on subsequent scans was used to assess changes in GEJ location between fractions; displacement was also correlated with clinical and respiratory variables. Results: The mean absolute random error was 1.69 mm (range, 0.11-4.11 mm) in the lateral direction, 1.87 mm (range, 0.51-4.09 mm) in the anterior-posterior (AP) direction, and 3.09 mm (range, 0.99-6.16 mm) in the superior-inferior (SI) direction. The mean absolute systemic GEJ displacement between fractions was 2.88 mm lateral ({>=}5 mm in 14%), mostly leftward; 2.90 mm ({>=}5 mm in 14%) AP, mostly anterior; and 6.77 mm ({>=}1 cm in 18%) SI, mostly inferior. Variations in tidal volume and diaphragmatic excursion during treatment correlated strongly with systematic SI GEJ displacement (r = 0.964, p < 0.0001; and r = 0.944, p < 0.0001, respectively) and moderately with systematic AP GEJ displacement (r = 0.678, p = 0.0005; r = 0.758, p < 0.0001, respectively). Systematic displacement in the inferior direction resulted in higher-than-intended doses ({>=}60 Gy) to the GEJ, with increased hot-spot to the adjacent stomach and lung base. Conclusion: We found large (>1-cm) interfractional displacements in the GEJ in the SI (especially inferior) direction that was not accounted for when skeletal alignment alone was used for patient positioning. Because systematic displacement in the SI direction had dosimetric impact and correlated with tidal volume, better accounting for depth of breathing is needed to reduce interfractional variability.

  9. Geographical variation in reproductive character displacement in mate choice by male sailfin mollies.

    PubMed

    Gabor, C R; Ryan, M J

    2001-05-22

    Female Amazon mollies, Poecilia formosa, are a unisexual species that reproduce by gynogenesis. They must coexist and mate with males of other species (usually the mollies Poecilia latipinna or Poecilia mexicana) to induce embryogenesis, but inheritance is strictly maternal. We examined the mating preference of the male sailfin molly, P. latipinna, for female sailfin mollies versus Amazon mollies, P. formosa. We compared the mating preferences of sympatric and allopatric populations collected throughout the Gulf Coast of North America. Male P. latipinna from six populations sympatric with Amazon mollies showed a significantly greater strength of preference for conspecific sailfin females than males from five populations that were allopatric with Amazon mollies. These results provide strong evidence for reproductive character displacement of male mate choice in sympatry. Furthermore, the large geographical range of populations that we tested revealed variation among populations within sympatry and allopatry, indicating that it is important to evaluate a large number of populations when examining reproductive character displacement. PMID:11375091

  10. Correlated Formation and Stability of SIA Loops and Stacking Fault Tetrahedra in High Energy Displacement Cascades in Copper,

    SciTech Connect

    Voskoboinikov, Roman E [University of Liverpool; Osetskiy, Yury N [ORNL; Bacon, David J [University of Liverpool

    2005-01-01

    Atomistic modeling was conducted for an investigation of primary damage creation, self-interstitial and vacancy clusters formation, and their stability in high energy displacement cascades in copper. The simulations were carried out for a wide range of temperatures (100 K {le} T {le} 900 K) and primary knock-on atom (PKA) energies 5 keV {le} Epka {le} 25 keV. This study of over 400 cascades is the largest yet reported for this metal. At least 20 cascades for each (Epka, T) pair were simulated in order to ensure statistical reliability of the results. The number of surviving point defects for each cascade and the mean value for cascades at the same temperature and PKA energy were found. The corresponding fraction of self-interstitial atoms (SIA) in dislocation loops and vacancies in stacking fault tetrahedron (SFT)-like clusters was calculated. Strong spatial and size correlation of SFTs and SIA clusters at low temperatures were established. In the context of high dose irradiation and the spatial overlap of displacement cascades, the stability of SFTs and dislocation loops inside an overlapping cascade region was investigated. It was observed that an SFT destroyed in the collision phase by a cascade is always recreated. On being completely enveloped by the region of displaced atoms, both SFT and SIA dislocation loops are destroyed with corresponding decrease of the number of residual point defects, whereas partial overlapping leads to increase in size of both types of cluster.

  11. Ab initio molecular dynamics simulations of threshold displacement energies in SrTiO3

    SciTech Connect

    Liu, Bin [ORNL] [ORNL; Xiao, Haiyan [University of Tennessee, Knoxville (UTK)] [University of Tennessee, Knoxville (UTK); Zhang, Yanwen [ORNL] [ORNL; Aidhy, Dilpuneet S [ORNL] [ORNL; Weber, William J [ORNL] [ORNL

    2013-01-01

    Ab initio molecular dynamics simulations have been carried out to study low-energy recoil events in SrTiO3. The threshold displacement energies are shown to be strongly dependent on both the orientation and the corresponding atomic arrangement. The minimum threshold displacement energies are 13 eV for an O recoil along the <100> O-O chain, 25 eV for a Sr recoil along the <100> Sr-Sr chain and 38 eV for a Ti recoil along the <110> Ti-Ti chain. The weighted average threshold displacement energies along the primary crystallographic directions are 35.7, 53.5 and > 64.9 eV for O, Sr and Ti, respectively. The interstitial configurations produced by the recoil events are <100> and <111> split-interstitials for O and Sr, respectively, together with a Ti interstitial occupying a distorted bridge position between two Sr sites. It is found that the recoil events in SrTiO3 are partial- charge transfer assisted processes, and the partial- charge transfer plays an important role in these recoil events.

  12. A servo-control system for detecting micro-displacement based on interferometry

    NASA Astrophysics Data System (ADS)

    Hui, Jianhua; Yang, Yongying; Liang, Jiao; Lu, Chunhua

    2007-01-01

    Enhancing the measurement precision of the micro-displacement has become a significant trend of modern technology. This paper describes a servo-control system that can detect the displacement up to the order of nanometer on the basis of interference and resonance intensifying. The micro-displacement variance of a sample would cause the amplitude change of the microprobe, vibrating at the resonance frequency. By a point-diffraction-interference system, the amplitude change can converted to electrical signal after the photodiode detector. Then, this signal is sent to the feedback control system with PID model. Amplified by the high-voltage circuit, the feedback signal drives the piezoelectric crystal under the sample working stage to flex, keeping the distance constant between the microprobe and the sample. The circuit design possesses compact structure, good noise resistance and high stability. Apply this system to an atomic force microscope (AFM) to scan the sample surface coating aluminum fluoride. The results show that under the condition of 100 kHz resonance frequency, the image quality of sample's microscale topography with this servo-control system is evidently better than that with open-loop system. The operation only costs dozens of seconds to finish scanning 400×400 points and the precision is better than the order of nanometer.

  13. Model for transport and reaction of defects and carriers within displacement cascades in gallium arsenide

    NASA Astrophysics Data System (ADS)

    Wampler, William R.; Myers, Samuel M.

    2015-01-01

    A model is presented for recombination of charge carriers at evolving displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with the details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers, and defects within a representative spherically symmetric cluster of defects. The initial radial defect profiles within the cluster were determined through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to displacement damage from energetic particle irradiation.

  14. Complementary heterogeneous/homogeneous protocols for the synthesis of densely functionalized benzo[d]sultams: C-C bond formation by intramolecular nucleophilic aromatic fluorine displacement.

    PubMed

    Penso, Michele; Albanese, Domenico; Landini, Dario; Lupi, Vittoria; Tagliabue, Aaron

    2008-09-01

    Polyfunctionalized benzo[d]sultams 7 and 8, which contain an alpha-amino acid unit, have been synthesized from the corresponding open chain (pentafluorobenzene)sulfonamides 4 by complementary solid-liquid phase transfer catalysis (SL-PTC) and homogeneous protocols. The cyclization step proceeds through the intramolecular nucleophilic displacement of an aromatic fluorine atom. PMID:18687000

  15. Exchange energy density definitions from the optimized exchange-force, exemplified for non-relativistic Ne and Ar-like atomic ions in the limit of large nuclear charge

    Microsoft Academic Search

    N. H. March; A. Krishtal; C. Van Alsenoy; J. D. Talman

    2011-01-01

    An alternative exchange energy density (eed) in DFT is first proposed, depending on the optimized exchange force (OEF). It\\u000a is evaluated using a numerical form of OEF for the non-relativistic Ne-like atomic ion series for atomic number Z = 92. Comparison is made with the Dirac form of eed available analytically. Related results are also presented for Ar-like\\u000a atomic ions.

  16. Mega displacement waves in glacial lakes: evidence from Laguna Safuna Alta, Peru

    NASA Astrophysics Data System (ADS)

    Reynolds, J. M.; Heald, A. P.; Zapata, M.

    2003-04-01

    An anomalously large displacement wave and overtopping event have been investigated at Laguna Safuna Alta, Cordillera Blanca, Peru. On 22nd April 2002, 10M m^3 or more of rock fell from the western valley slope into the southern end of the lake and onto the lower 100 m of the glacier. Evidence from the landslide scar indicates that the mechanism of failure was principally flexural toppling of quartzites, mudstones and sandstones with beds of anthracite. Bathymetric surveys taken before and after the landslide show that about 6.4M m^3 of material entered the lake during the event. The resulting displacement wave was 80--100 m high, overtopping the end moraine, which is 80 m at its lowest point. Oscillating rebound waves had amplitudes up to around 80 m. The initial displacement wave and the largest rebound waves caused erosion of the inner and outer flanks of the moraine, damaged lake security structures, and killed cattle that had been grazing in the area; but the moraine dam remained substantially intact and the resulting flood was largely contained within a lower lake, Laguna Safuna Baja. Active backscarps and tension cracks in the slope adjacent to the rockfall indicate that a further 5M m^3 of rock may fail. Modelling the steady state stability of the now weakened moraine dam provides factors of safety below unity against a large-scale failure of the inner slope of the moraine. The moraine dam cannot be expected to resist a second large displacement wave and mitigation strategies are therefore being developed. The height of the wave produced during this event was an order of magnitude greater than values commonly reported and designed for in glacial lake remediation works.

  17. Scalable, Time-Responsive, Digital, Energy-Efficient Molecular Circuits using DNA Strand Displacement

    Microsoft Academic Search

    Ehsan Chiniforooshan; David Doty; Lila Kari; Shinnosuke Seki

    2010-01-01

    We propose a novel theoretical biomolecular design to implement any Boolean\\u000acircuit using the mechanism of DNA strand displacement. The design is scalable:\\u000aall species of DNA strands can in principle be mixed and prepared in a single\\u000atest tube, rather than requiring separate purification of each species, which\\u000ais a barrier to large-scale synthesis. The design is time-responsive: the

  18. Dealing with the Effects of Sensor Displacement in Wearable Activity Recognition

    PubMed Central

    Banos, Oresti; Toth, Mate Attila; Damas, Miguel; Pomares, Hector; Rojas, Ignacio

    2014-01-01

    Most wearable activity recognition systems assume a predefined sensor deployment that remains unchanged during runtime. However, this assumption does not reflect real-life conditions. During the normal use of such systems, users may place the sensors in a position different from the predefined sensor placement. Also, sensors may move from their original location to a different one, due to a loose attachment. Activity recognition systems trained on activity patterns characteristic of a given sensor deployment may likely fail due to sensor displacements. In this work, we innovatively explore the effects of sensor displacement induced by both the intentional misplacement of sensors and self-placement by the user. The effects of sensor displacement are analyzed for standard activity recognition techniques, as well as for an alternate robust sensor fusion method proposed in a previous work. While classical recognition models show little tolerance to sensor displacement, the proposed method is proven to have notable capabilities to assimilate the changes introduced in the sensor position due to self-placement and provides considerable improvements for large misplacements. PMID:24915181

  19. Simultaneous measurement of displacement and temperature based on thin-core fiber modal interferometer

    NASA Astrophysics Data System (ADS)

    Wu, Jixuan; Miao, Yinping; Song, Binbin; Lin, Wei; Zhang, Kailiang; Zhang, Hao; Liu, Bo; Yao, Jianquan

    2015-04-01

    An optical-fiber sensor based on a thin core fiber (TCF) has been proposed and experimentally demonstrated for simultaneous measurement of displacement and temperature. This in-line sensor consists of a segment of TCF between two segments of single-mode fibers (SMFs), and the interference between the core mode and the cladding mode of the TCF occurs. The transmission spectral responses to displacement as well as environmental temperature have been investigated. Experimental results show that the displacement sensitivities of -0.01028 nm/?m and -0.01535 nm/?m for a displacement range of 0-650 ?m have been achieved, and the corresponding temperature sensitivities reach about 0.00942 nm/°C and 0.00493 nm/°C within a large temperature range of 20-90 °C, respectively. The proposed sensor exhibits such advantages as simple structure, compact size, ease of fabrication, high sensitivity, etc. Therefore, it has potential applications in accurate multi-parameter measurements.

  20. FPGA-based smart sensor for online displacement measurements using a heterodyne interferometer.

    PubMed

    Vera-Salas, Luis Alberto; Moreno-Tapia, Sandra Veronica; Garcia-Perez, Arturo; de Jesus Romero-Troncoso, Rene; Osornio-Rios, Roque Alfredo; Serroukh, Ibrahim; Cabal-Yepez, Eduardo

    2011-01-01

    The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application. PMID:22164040

  1. Development of displacement of centre of mass during independent walking in children.

    PubMed

    Dierick, Frédéric; Lefebvre, Caroline; van den Hecke, Adélaïde; Detrembleur, Christine

    2004-08-01

    The aims of this study were to assess the characteristics of three-dimensional displacement of the centre of mass of the body (CMb) during walking in healthy children and to compare it with those of young adults. Twenty-one children (11 males, 10 females; age range 1 to 9 years) were recruited from the nursery and school attached to the Université catholique de Louvain, Brussels, Belgium; and three young adults (one male two females; mean age 26 years 4 months) were recruited from the Rehabilitation and Physical Medicine Unit of the same university. Displacement of CMb was assessed at different walking velocities in the children and adults by two successive mathematical integrations of ground reaction forces, measured by a large strain-gauge force platform. Displacement of CMb was controlled for leg length of the participant to eliminate the scaling effect that is dependent on growth. Results showed that vertical and lateral amplitudes of the CMb when controlled for leg length were greater for children before 4 years of age and that the forward amplitude when controlled for leg length was greater for children before 7 years of age. We conclude that the development of mature human CMb displacement during independent walking is a gradual neural process, evolving until the age of 7 years. PMID:15287244

  2. Detection and localization of inclusions in plates using inversion of point actuated surface displacements

    NASA Astrophysics Data System (ADS)

    Bucaro, J. A.; Romano, A. J.; Abraham, P.; Dey, S.

    2004-01-01

    A numerical simulation is carried out demonstrating the use of plate surface vibration measurements for detecting and locating inclusions within the structure. A finite element code is used to calculate normal surface displacement for both steel and mortar plates subjected to a monochromatic point force. The data is generated for the homogeneous plate and the identical plate within which exists a small rectangular inclusion. It is observed that when the elastic modulus of the inclusion is orders of magnitude lower than the base material, resonances of the inclusion produce large local displacements that are readily observed in the raw displacement data. For more modest moduli differences, there are no such directly observable effects. In this case, three inverse algorithms are used to process the displacement data. The first two are local inversion techniques that each yield a spatial map of the elastic modulus normalized by density. These algorithms successfully detect and localize the inclusion based on its modulus difference from that of the base plate. The third technique uses a form of the inhomogeneous equation of motion to obtain the induced force distribution connected with the inclusion. The spatial mapping of this force also successfully detects and localizes the inclusion.

  3. Free response of a system with negative viscous damping and displacement-dependent dry friction damping

    NASA Astrophysics Data System (ADS)

    Ferri, Aldo A.; Whiteman, Wayne E.

    2007-10-01

    A stability analysis is conducted of an autonomous single-degree-of-freedom system damped with negative viscous damping and a displacement-dependent Coulomb friction force. The geometry of the dry friction damping element yields a friction force that grows linearly with the system displacement. The most direct application of this system is in the study of a turbomachinery blade with shroud interfaces designed to achieve this geometry. Recent studies have shown that the damping of systems with this type of displacement-dependent dry friction force resembles linear structural damping and suggests that this arrangement may be an effective means of flutter suppression in these turbine and fan blade applications. For this study, the inclusion of negative viscous damping is used in order to approximate destabilizing aerodynamic forces. An exact analysis is conducted to determine the stability of this autonomous system. Results show that energy losses from the displacement-dependent dry friction damper are large enough to achieve local and even global stability under certain conditions.

  4. The comparative performance of Roots type aircraft engine superchargers as affected by change in impeller speed and displacement

    NASA Technical Reports Server (NTRS)

    Ware, Marsden; Wilson, Ernest E

    1929-01-01

    This report presents the results of tests made on three sizes of roots type aircraft engine superchargers. The impeller contours and diameters of these machines were the same, but the length were 11, 8 1/4, and 4 inches, giving displacements of 0.509, 0.382, and 0.185 cubic foot per impeller revolution. The information obtained serves as a basis for the examination of the individual effects of impeller speed and displacement on performance and of the comparative performance when speed and displacement are altered simultaneously to meet definite service requirements. According to simple theory, when assuming no losses, the air weight handled and the power required for a given pressure difference are directly proportional to the speed and the displacement. These simple relations are altered considerably by the losses. When comparing the performance of different sizes of machines whose impeller speeds are so related that the same service requirements are met, it is found that the individual effects of speed and displacement are canceled to a large extent, and the only considerable difference is the difference in the power losses which decrease with increase in the displacement and the accompanying decrease in speed. This difference is small in relation to the net power of the engine supercharger unit, so that a supercharger with short impellers may be used in those applications where the space available is very limited with any considerable sacrifice in performance.

  5. Quantum Electrodynamics of Atomic Resonances

    NASA Astrophysics Data System (ADS)

    Ballesteros, Miguel; Faupin, Jérémy; Fröhlich, Jürg; Schubnel, Baptiste

    2015-07-01

    A simple model of an atom interacting with the quantized electromagnetic field is studied. The atom has a finite mass m, finitely many excited states and an electric dipole moment, , where and is proportional to the elementary electric charge. The interaction of the atom with the radiation field is described with the help of the Ritz Hamiltonian, , where is the electric field, cut off at large frequencies. A mathematical study of the Lamb shift, the decay channels and the life times of the excited states of the atom is presented. It is rigorously proven that these quantities are analytic functions of the momentum of the atom and of the coupling constant , provided and and are sufficiently small. The proof relies on a somewhat novel inductive construction involving a sequence of `smooth Feshbach-Schur maps' applied to a complex dilatation of the original Hamiltonian, which yields an algorithm for the calculation of resonance energies that converges super-exponentially fast.

  6. Atomically-resolved mapping of polarization and electric fields across ferroelectric-oxide interfaces by Z-contrast imaging

    SciTech Connect

    Chang, Hye Jung [ORNL; Kalinin, Sergei [Oak Ridge National Laboratory (ORNL); Morozovska, A. N. [National Academy of Science of Ukraine, Kiev, Ukraine; Huijben, Mark [University of Twente, Enschede, Netherlands; Chu, Ying-Hao [National Chiao Tung University, Hsinchu, Taiwan; Yu, P [University of California, Berkeley; Ramesh, R. [University of California, Berkeley; Eliseev, E. A. [National Academy of Science of Ukraine, Kiev, Ukraine; Svechnikov, S. V. [National Academy of Science of Ukraine, Kiev, Ukraine; Pennycook, Stephen J [ORNL; Borisevich, Albina Y [ORNL

    2011-01-01

    Direct atomic displacement mapping at ferroelectric interfaces by aberration corrected scanning transmission electron microscopy(STEM) (a-STEM image, b-corresponding displacement profile) is combined with Landau-Ginsburg-Devonshire theory to obtain the complete interface electrostatics in real space, including separate estimates for the polarization and intrinsic interface charge contributions.

  7. Wireless laser range finder system for vertical displacement monitoring of mega-trusses during construction.

    PubMed

    Park, Hyo Seon; Son, Sewook; Choi, Se Woon; Kim, Yousok

    2013-01-01

    As buildings become increasingly complex, construction monitoring using various sensors is urgently needed for both more systematic and accurate safety management and high-quality productivity in construction. In this study, a monitoring system that is composed of a laser displacement sensor (LDS) and a wireless sensor node was proposed and applied to an irregular building under construction. The subject building consists of large cross-sectional members, such as mega-columns, mega-trusses, and edge truss, which secured the large spaces. The mega-trusses and edge truss that support this large space are of the cantilever type. The vertical displacement occurring at the free end of these members was directly measured using an LDS. To validate the accuracy and reliability of the deflection data measured from the LDS, a total station was also employed as a sensor for comparison with the LDS. In addition, the numerical simulation result was compared with the deflection obtained from the LDS and total station. Based on these investigations, the proposed wireless displacement monitoring system was able to improve the construction quality by monitoring the real-time behavior of the structure, and the applicability of the proposed system to buildings under construction for the evaluation of structural safety was confirmed. PMID:23648650

  8. Wireless Laser Range Finder System for Vertical Displacement Monitoring of Mega-Trusses during Construction

    PubMed Central

    Park, Hyo Seon; Son, Sewook; Choi, Se Woon; Kim, Yousok

    2013-01-01

    As buildings become increasingly complex, construction monitoring using various sensors is urgently needed for both more systematic and accurate safety management and high-quality productivity in construction. In this study, a monitoring system that is composed of a laser displacement sensor (LDS) and a wireless sensor node was proposed and applied to an irregular building under construction. The subject building consists of large cross-sectional members, such as mega-columns, mega-trusses, and edge truss, which secured the large spaces. The mega-trusses and edge truss that support this large space are of the cantilever type. The vertical displacement occurring at the free end of these members was directly measured using an LDS. To validate the accuracy and reliability of the deflection data measured from the LDS, a total station was also employed as a sensor for comparison with the LDS. In addition, the numerical simulation result was compared with the deflection obtained from the LDS and total station. Based on these investigations, the proposed wireless displacement monitoring system was able to improve the construction quality by monitoring the real-time behavior of the structure, and the applicability of the proposed system to buildings under construction for the evaluation of structural safety was confirmed. PMID:23648650

  9. Atomic structure of the sweet-tasting protein thaumatin I at pH 8.0 reveals the large disulfide-rich region in domain II to be sensitive to a pH change

    SciTech Connect

    Masuda, Tetsuya, E-mail: t2masuda@kais.kyoto-u.ac.jp [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Department of Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Ohta, Keisuke [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Department of Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Mikami, Bunzo [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)] [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Kitabatake, Naofumi [Department of Foods and Human Nutrition, Notre Dame Seishin University, Okayama 700-8516 (Japan)] [Department of Foods and Human Nutrition, Notre Dame Seishin University, Okayama 700-8516 (Japan); Tani, Fumito [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan) [Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan); Department of Natural Resources, Graduate School of Global Environmental Studies, Kyoto University, Gokasho, Uji, Kyoto 611-0011 (Japan)

    2012-03-02

    Highlights: Black-Right-Pointing-Pointer Structure of a recombinant thaumatin at pH 8.0 determined at a resolution of 1.0 A. Black-Right-Pointing-Pointer Substantial fluctuations of a loop in domain II was found in the structure at pH 8.0. Black-Right-Pointing-Pointer B-factors for Lys137, Lys163, and Lys187 were significantly affected by pH change. Black-Right-Pointing-Pointer An increase in mobility might play an important role in the heat-induced aggregation. -- Abstract: Thaumatin, an intensely sweet-tasting plant protein, elicits a sweet taste at 50 nM. Although the sweetness remains when thaumatin is heated at 80 Degree-Sign C for 4 h under acid conditions, it rapidly declines when heating at a pH above 6.5. To clarify the structural difference at high pH, the atomic structure of a recombinant thaumatin I at pH 8.0 was determined at a resolution of 1.0 A. Comparison to the crystal structure of thaumatin at pH 7.3 and 7.0 revealed the root-mean square deviation value of a C{alpha} atom to be substantially greater in the large disulfide-rich region of domain II, especially residues 154-164, suggesting that a loop region in domain II to be affected by solvent conditions. Furthermore, B-factors of Lys137, Lys163, and Lys187 were significantly affected by pH change, suggesting that a striking increase in the mobility of these lysine residues, which could facilitate a reaction with a free sulfhydryl residue produced via the {beta}-elimination of disulfide bonds by heating at a pH above 7.0. The increase in mobility of lysine residues as well as a loop region in domain II might play an important role in the heat-induced aggregation of thaumatin above pH 7.0.

  10. Multi-Method Dispatch Using Multiple Row Displacement

    E-print Network

    Szafron, Duane

    Multi-Method Dispatch Using Multiple Row Displacement Candy Pang, Wade Holst, Yuri Leontiev,wade,yuri,duane}@cs.ualberta.ca Abstract. Multiple Row Displacement (MRD) is a new dispatch tech- nique for multi-method languages-receiver projection. MRD uses comparable space to the other techniques, but has faster dispatch performance. 1

  11. Semen displacement as a sperm competition strategy in humans (2004)

    Microsoft Academic Search

    Gordon G. Gallup; Rebecca L. Burch

    We examine some of the implications of the possibility that the human penis may have evolved to compete with sperm from other males by displacing rival semen from the cervical end of the vagina prior to ejaculation. The semen displacement hypothesis integrates considerable information about genital morphology and human reproductive behavior, and can be used to generate a number of

  12. Semen Displacement as a Sperm Competition Strategy in Humans

    Microsoft Academic Search

    Gordon G. Gallup; Rebecca L. Burch

    We examine some of the implications of the possibility that the human penis may have evolved to compete with sperm from other males by displacing rival semen from the cervical end of the vagina prior to ejaculation. The semen displacement hypothesis integrates considerable information about genital morphology and human reproductive behavior, and can be used to generate a number of

  13. A note on dynamic displacement measurements using Hall effect sensors

    Microsoft Academic Search

    J. H. Giovanola; T. Kobayashi; R. W. Klopp; T. Gaines; R. Arwood

    1989-01-01

    A transducer suitable for dynamic displacement measurements is described. The transducer uses a commercially available Hall effect sensor and a permanent magnet. Displacements are obtained by measuring the variation in magnetic field strength along the permanent magnet with the Hall effect sensor. To illustrate the capabilities of the transducer, we discuss three application examples. The first example demonstrates the good

  14. Observation of displacement momentum in normal and chiral dielectrics.

    PubMed

    Rikken, G L J A; van Tiggelen, B A

    2013-05-10

    We argue that displacement currents in dielectrics are in general accompanied by mechanical momentum through total momentum conservation, quite analogous to the Einstein-de Haas effect. We report the first observation of such displacement momentum, generated by a time varying electric field in a dielectric, and by a time varying magnetic field in a chiral dielectric. PMID:23705708

  15. Optical fiber digital speckle pattern correlation method for displacement measurement

    Microsoft Academic Search

    Rongxun Liu; Xinwei Liu

    1995-01-01

    This paper briefly reviews present situation on optical fiber-speckle method used for measuring displacements or deformations of an object, and the optical fiber-digital white light speckle patterns correlation method for whole field displacement measurement on a remote surface of a trial object is revealed. The principle of correlation method is demonstrated. A special program for image correlation analysis by computer

  16. Comparisons of empirical models for unstable miscible displacement

    Microsoft Academic Search

    Newley; T. M. J

    1989-01-01

    In this paper the authors compare the Koval, Todd and Longstaff and Fayers models of unstable miscible displacement. They consider both flow in a five-spot geometry and displacements under the influence of gravity. Model predictions are compared with available experimental data and the results of direct simulation. The authors show that the Todd and Longstaff and Fayers models are in

  17. The effect of bone displacement operations on facial soft tissues.

    PubMed

    Habib, Ali; Hisham, Ahmed

    2013-01-01

    A novel biomechanical model for face soft tissue (skin, mucosa, and muscles) is introduced to investigate the effect of mandible and chin bone displacement on the overall appearance of the patient's face. Nonlinear FE analysis is applied to the model and the results obtained are used to help surgeons to decide the amount of displacement required. PMID:24110836

  18. The successive displacement process: Oil recovery during blowdown

    SciTech Connect

    Irwin, D.D.; Batychy, J.P.

    1996-12-31

    Much of Western Canada`s conventional crude oil occurs in vertically-continuous reefal carbonate structures. A common strategy has been to support oil production through downward vertical gas displacement. The gravity stable displacement yields excellent conformance and high oil recoveries with typical residual levels of 20% pore volume. Once the oil zone has been depleted leaving only a sandwich loss, the pools enter a blowdown phase to produce the gas cap from the top of structure. During the blowdown phase, if there is an underlying aquifer, the oil sandwich is displaced upwards into the previously gas-displaced oil zone, trapping gas. Due to the presence of the trapped gas saturation and the low connate water saturation (typical of carbonate reefs), the remaining oil saturation in this zone, as it is displaced by the underlying water is reduced to near miscible levels (10 - 15% PV), mobilizing incremental oil equal to 5 - 10% PV. Whether or not there an aquifer is present, bottom water injection can be applied to ensure displacement through the entire gas-displacement oil zone. The Successive Displacement (SDP), as this tertiary waterflood concept has been named, has been confirmed with full-diameter reservoir-condition core tests on carbonate cores in the laboratory. Observation from the initial stages of a full-field SDP application in Imperial Oil`s Bonnie Glen reservoir after about four years of operation provide further encouragement with performance indicating a reduction in the residual of 5-6% PV.

  19. Performance comparison of fiber optic tips in interferrometric displacement measurement

    Microsoft Academic Search

    Erik A Moro; Anthony D Puckett; Rick Grahn; Hussain Karimi; Kyle Wilson

    2010-01-01

    Fiber optic displacement sensors have many potential advantages over traditional displacement measurement techniques, including small size, immunity to electromagnetic interference, electrical isolation, and high resolution. In this report, we focus on an interferometric fiber optic sensor, where the gap between the fiber tip and the device under test forms a Fabry-Perot resonant cavity. An optical interrogator measures the reflected intensity

  20. Time-Complexity of Multilayered DNA Strand Displacement Circuits

    Microsoft Academic Search

    Georg Seelig; David Soloveichik

    2009-01-01

    Recently we have shown how molecular logic circuits with many components arranged in multiple layers can be built using DNA strand displacement reactions. The potential applications of this and similar technologies inspire the study of the computation time of mul- tilayered molecular circuits. Using mass action kinetics to model DNA strand displacement-based circuits, we discuss how computation time scales with

  1. The determination of bridge displacement using measured acceleration

    Microsoft Academic Search

    Ki-Tae Park; Sang-Hyo Kim; Heung-Suk Park; Kyu-Wan Lee

    2005-01-01

    LVDT is generally used as the method for displacement measurement. But this method cannot be applied effectively if the bridge height is so high that it is difficult to install the sensor and the measured results are not as reliable and accurate. In this paper, we suggest the initial velocity estimation method for the displacement determination algorithm to overcome these

  2. Design of Retaining Walls for Outward Displacement in Earthquakes

    Microsoft Academic Search

    J. H. Wood

    Methods for computing the outward permanent displacement of earth retaining walls, both associated with bridges or constructed as separate structures, on State Highways in New Zealand have been reviewed and compared. The most suitable methods of estimating displacements were found to be those of Ambraseys and Menu (1998) and Jibson (2007). Both these methods use readily evaluated regression equations relating

  3. Microscopic 3-D displacement field measurements using digital speckle photography

    Microsoft Academic Search

    Linda Larsson; Mikael Sjödahl; Fredrik Thuvander

    2004-01-01

    A technique to measure object shape and 3-D displacement fields in micro-scale is offered by microscopic stereo digital speckle photography. The displacement of the random features that are often present on many engineering surfaces when viewed in a microscope is measured with the system, using image correlation. In this paper the equipment, physical model and calibration routines are described. The

  4. Vertical displacement determination of a levitated superconducting mass

    Microsoft Academic Search

    Yusaku Fujii; Fuyuhiko Shiota; Yukinobu Miki; Kan Nakayama; Tadashi Morokuma

    1999-01-01

    The determination of the vertical displacement of the center of gravity of a levitated superconducting body in the National Research Laboratory of Metrology (NRLM) superconducting magnetic levitation project, which is aimed at establishing a new definition of the unit of mass based on the fundamental constants, is discussed. The translation displacement (three degrees of freedom) and the attitude change (three

  5. Methods for measuring small displacements of television images

    Microsoft Academic Search

    CIRO CAFFORIO; FABIO ROCCA

    1976-01-01

    Various techniques are described to measure, small displacements of television images. If two successive video frames are considered, their differences are approximately a linear combination of the components of the displacement of the object. If all the points of the frame undergo the same movement, then the velocity estimation problem is solved using linear estimation. However, if some points belong

  6. Theoretical and experimental study on regenerative rotary displacer Stirling engine

    Microsoft Academic Search

    Luca RAGGI; M. Katsuta; N. Isshiki; S. Isshiki

    1997-01-01

    Recently a quite new type of hot air engine called rotary displacer engine, in which the displacer is a rotating disk enclosed in a cylinder, has been conceived and developed. The working gas, contained in a notch excavated in the disk, is heated and cooled alternately, on account of the heat transferred through the enclosing cylinder that is heated at

  7. Displacement Synthesis of Cu Shells Surrounding Co Nanoparticles

    E-print Network

    Guo, John Zhanhu

    Displacement Synthesis of Cu Shells Surrounding Co Nanoparticles Zhanhu Guo,a,b, * Challa S. S. R 70813, USA Copper shells were fabricated by a displacement method around Co nanoparticles (3.2 0.6 nm) at room temperature in a copper-citrate aqueous electrolyte. The nanoparticles were synthesized by a wet

  8. The human penis as a semen displacement device

    Microsoft Academic Search

    Gordon G. Gallup Jr; Rebecca L. Burch; Mary L. Zappieri; Rizwan A. Parvez; Malinda L. Stockwell; Jennifer A. Davis

    2003-01-01

    Inanimate models were used to assess the possibility that certain features of the human penis evolved to displace semen left by other males in the female reproductive tract. Displacement of artificial semen in simulated vaginas varied as a function of glans\\/coronal ridge morphology, semen viscosity, and depth of thrusting. Results obtained by modifying an artificial penis suggest that the coronal

  9. A Novel and High-Precision Optical Displacement Sensor

    Microsoft Academic Search

    A. Rostami; M. Noshad; H. Hedayati; A. Ghanbari; F. Janabi-Sharifi

    Summary In this paper, theoretical and experimental investigation of a novel compact and high-precision (0.2 nm) optical displacement sensor is presented. The sensor operation is based on optical intensity modulation due to diffraction. A circular disk, including a central transmitter and circumferential receivers (8 and 12 configurations), is considered as high precision displacement sensor. Effects of the number of receivers

  10. MSA Comparative Crystal Chemistry The Analysis of Harmonic Displacement Factors

    E-print Network

    Downs, Robert T.

    1 MSA Comparative Crystal Chemistry Chapter 7 The Analysis of Harmonic Displacement Factors R of the displacement ellipsoids for a Si2O7 group in - quartz, SiO2, at 298 K and 838 K (Kihara, 1990). The ellipsoids be mathematically defined with a probability distribution function (p.d.f.). If we assume harmonic restoring forces

  11. Contemporary Vertical Surface Displacements in Yellowstone National Park

    Microsoft Academic Search

    J. R. Pelton; R. B. Smith

    1982-01-01

    The comparison of repeated geodetic leveling measurements is a well-established technique for the detection of contemporary vertical displacements Of the Earth's surface (see the reviews by Brown and Oliver [1976] and Vanicek et al. [1980]). The basis for contemporary vertical surface displacement studies in Yellowstone National Park was established in 1923 when leveling of second-order precision provided vertical control throughout

  12. Modified Newmark model for seismic displacements of compliant slopes

    Microsoft Academic Search

    Steven L. Kramer; Matthew W. Smith

    1997-01-01

    Newmark sliding block analyses are widely used for estimation of permanent displacements of slopes in earthquakes. The conventional Newmark model, however, neglects the dynamic response of the material above a potential failure surface. Decoupled procedures have been developed to account for that response, but they neglect the effects of permanent displacements on the response. A modified Newmark analysis that considers

  13. Airbag roll marks & displaced rocks and soil

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Looking southwest from the lander, soil disturbances indicating the spacecraft rolled through the landing site are visible. Arriving from the east, the lander, still encased in its protective airbags, rolled up a slight rise and then rolled back down to its final position. The inset at left shows displaced rocks near the rock 'Flat Top.' Dark patches of disturbed soil indicate where the rocks had originally rested Both insets show rocks that were pushed into the soil from the weight of the lander, visible from the areas of raised rims of dark, disturbed soil around several rocks. The south summit of Twin Peaks is in the background, while a lander petal, deflated airbag, and rear rover deployment ramp are in the foreground.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division of the California Institute of Technology (Caltech).

  14. Gage for measuring displacements in rock samples

    DOEpatents

    Holcomb, David J. (Albuquerque, NM); McNamee, Michael J. (Albuquerque, NM)

    1986-01-01

    A gage for measuring diametral displacement within a rock sample for use in a rock mechanics laboratory and in the field, comprises a support ring housing a linear variable differential transformer, a mounting screw, and a leaf spring. The mounting screw is adjustable and defines a first point of contact with the rock sample. The leaf spring has opposite ends fixed to the inner periphery of the mounting ring. An intermediate portion of the leaf spring projecting radially inward from the ring is formed with a dimple defining a second point of contact with the sample. The first and second points of contact are diametrically opposed to each other. The LVDT is mounted in the ring with its axis parallel to the line of measurement and its core rod received in the dimple of the leaf spring. Any change in the length of the line between the first and second support points is directly communicated to the LVDT. The leaf spring is rigid to completely support lateral forces so that the LVDT is free of all load for improved precision.

  15. Gage for measuring displacements in rock samples

    DOEpatents

    Holcomb, D.J.; McNamee, M.J.

    1985-07-18

    A gage for measuring diametral displacement within a rock sample for use in a rock mechanics laboratory and in the field, comprises a support ring housing a linear variable differential transformer (LVDT), a mounting screw, and a leaf spring. The mounting screw is adjustable and defines a first point of contact with the rock sample. The leaf spring has opposite ends fixed to the inner periphery of the mounting ring. An intermediate portion of the leaf spring projecting radially inward from the ring is formed with a dimple defining a second point of contact with the sample. The first and second points of contact are diametrically opposed to each other. The LVDT is mounted in the ring with its axis parallel to the line of measurement and its core rod received in the dimple of the leaf spring. Any change in the length of the line between the first and second support points is directly communicated to the LVDT. The leaf spring is rigid to completely support lateral forces so that the LVDT is free of all load for improved precision.

  16. atomic spectra 1 Atomic Spectra

    E-print Network

    Glashausser, Charles

    and for choice of photographic material. 8. E. Hecht: Optics, 2nd. Ed, 1987, Addison-Wesley. Chapter 5, pages 163. Preston and E. R. Dietz: The Art of Experimental Physics, pp. 397- 399, resolution of optical instruments- 169 (prisms) 9. G. R. Fowles: Introduction to Modern Optics, 2nd Ed., Holt, Rhinehart, #12;atomic

  17. Atomic Structure: Energy in Atoms

    NSDL National Science Digital Library

    National Science Teachers Association (NSTA)

    2010-05-24

    Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object is the third of three Science Objects in the Atomic Structure SciPack. It investigates

  18. Sheared sheet intrusions as a mechanism for lateral flank displacement on basaltic volcanoes: Applications to Réunion Island volcanoes

    NASA Astrophysics Data System (ADS)

    Cayol, V.; Catry, T.; Michon, L.; Chaput, M.; Famin, V.; Bodart, O.; Froger, J. L.; Romagnoli, C.

    2014-12-01

    Field work carried out on the Piton des Neiges volcano (Réunion Island) suggests that the injection of magma along detachments could trigger flank failure by conjugate opening and shear displacement [Famin and Michon, 2010]. We use 3D numerical models to compare the ability of purely opened sheet intrusions, sheared sheet intrusions, and normal faults to induce flank displacement on basaltic volcanoes (Figure). We assume that shear stress change on fractures which are not normal to a principal stress results from stress anisotropy of the host rock under gravity. Exploring a large range of stress anisotropies, fracture dips, and fracture depth over length ratios, we determine that the amount of shear displacement is independent of the proximity to the ground surface. Sheared sheet intrusions are the most efficient slip medium on volcanoes. Using our model in a forward way, we provide shear and normal displacements for buried fractures. Applying the model to a pile of sills at the Piton des Neiges volcano, we determine that the mean shear displacement caused by each intrusion was 3.7 m, leading to a total of a 180-260 m of lateral displacement for the 50 m high pile of sills. Using our model in an inverse way, we formulate a decision tree to determine some fracture characteristics and the host rock stress anisotropy from ratios of maximum surface displacements. This procedure provides a priori models, thus limits to the parameter space which can be further explored through a formal inversion. Applying this procedure to the 1.4 m co-eruptive flank displacement recorded at Piton de la Fournaise in 2007, we find that it probably originated from a shallow eastward-dipping sub-horizontal normal fault.

  19. A Linear, Millimetre Displacement-to-Frequency Transducer

    PubMed Central

    Agee, John T.; Petto, Four K.

    2012-01-01

    The paper presents a novel linear, high-fidelity millimetre displacement-to-frequency transducer, based on the resistive conversion of displacement into a proportional voltage, and then frequency. The derivation of the nonlinearity, fidelity and sensitivity of the transducer is presented. Experimental results confirm that a displacement of 0–100 mm is converted into a frequency range of 0–100 kHz, with a normalised fidelity factor of 99.91%, and a worst-case nonlinearity of less than 0.08%. Tests using laboratory standards show that a displacement of 10 mm is transduced with an accuracy of ±0.6%, and a standard deviation of 530 Hz. Estimates included in the paper show that the transducer could cost less than 1% of existing systems for millimeter displacement measurement. PMID:23112631

  20. High-stroke silicon-on-insulator MEMS nanopositioner: control design for non-raster scan atomic force microscopy.

    PubMed

    Maroufi, Mohammad; Fowler, Anthony G; Bazaei, Ali; Moheimani, S O Reza

    2015-02-01

    A 2-degree of freedom microelectromechanical systems nanopositioner designed for on-chip atomic force microscopy (AFM) is presented. The device is fabricated using a silicon-on-insulator-based process and is designed as a parallel kinematic mechanism. It contains a central scan table and two sets of electrostatic comb actuators along each orthogonal axis, which provides displacement ranges greater than ±10??m. The first in-plane resonance modes are located at 1274 Hz and 1286 Hz for the X and Y axes, respectively. To measure lateral displacements of the stage, electrothermal position sensors are incorporated in the design. To facilitate high-speed scans, the highly resonant dynamics of the system are controlled using damping loops in conjunction with internal model controllers that enable accurate tracking of fast sinusoidal set-points. To cancel the effect of sensor drift on controlled displacements, washout controllers are used in the damping loops. The feedback controlled nanopositioner is successfully used to perform several AFM scans in contact mode via a Lissajous scan method with a large scan area of 20??m × 20??m. The maximum scan rate demonstrated is 1?kHz. PMID:25725850