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1

Large displacement spherical joint  

DOEpatents

A new class of spherical joints has a very large accessible full cone angle, a property which is beneficial for a wide range of applications. Despite the large cone angles, these joints move freely without singularities.

Bieg, Lothar F. (Albuquerque, NM); Benavides, Gilbert L. (Albuquerque, NM)

2002-01-01

2

Atomic displacements in ferroelectric trigonal and orthorhombic boracite structures  

USGS Publications Warehouse

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.

Dowty, E.; Clark, J. R.

1972-01-01

3

A Microwave Atomic Point Contact Displacement Detector  

Microsoft Academic Search

A fundamental goal of nanomechanics is position detection at the Heisenberg limit. Recent experiments have employed single-electron transistor based position readout [1,2]. In contrast we use an atomic point contact (APC) as a displacement detector. In our measurements we probe the conductance of an APC formed between a nanomechanical beam and a fixed metal point to measure the harmonic motion

N. E. Flowers-Jacobs

2005-01-01

4

A microfabricated electrochemical actuator for large displacements  

Microsoft Academic Search

A large-displacement electrochemical actuator was designed, fabricated, and tested. The large displacement is obtained by using a corrugated membrane made by physical vapor deposition of Parylene sandwiched with an intermediate layer of sputtered platinum. The layered structure is approximately 8-?m thick, with 26 grooves approximately 120-?m deep, and with a radial period of 350 ?m. The electrochemical cell consists of

Tom Stanczyk; B. Ilic; Peter J. Hesketh; James G. Boyd

2000-01-01

5

Intrinsic Noise Properties of Atomic Point Contact Displacement Detectors  

Microsoft Academic Search

We measure the noise added by an atomic point contact operated as a displacement detector. With a microwave technique, we increase the measurement speed of atomic point contacts by a factor of 500. The measurement is then fast enough to detect the resonant motion of a nanomechanical beam at frequencies up to 60 MHz and sensitive enough to observe the

N. E. Flowers-Jacobs; D. R. Schmidt; K. W. Lehnert

2007-01-01

6

Molecular dynamics study of atomic displacements in disordered solid alloys  

NASA Astrophysics Data System (ADS)

The effects of atomic displacements on the energetics of alloys plays important role in the determining the properties of alloys. We studied the atomic displacements in disordered solid alloys using molecular dynamics and Monte-Carlo methods. The diffuse scattering of pure materials, copper, gold, nickel, and palladium was calculated. The experimental data for pure Cu was obtained from diffuse scattering intensity of synchrotron x-ray radiation. The comparison showed the advantages of molecular dynamics method for calculating the atomic displacements in solid alloys. The individual nearest neighbor separations were calculated for Cu 50Au50 alloy and compared to the result of XAFS experiment. The molecular dynamics method provided theoretical predictions of nearest neighbor pair separations in other binary alloys, Cu-Pd and Cu-Al for wide range of the concentrations. We also experimentally recovered the diffuse scattering maps for the Cu47.3Au52.7 and Cu85.2Al14.8 alloy.

Puzyrev, Yevgeniy S.

7

Atom interferometry using wave packets with constant spatial displacements  

SciTech Connect

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 are subsequently recombined, resulting in atom interference patterns that probe energy differences of {approx_equal}10{sup -34} J and can provide acceleration measurements that are insensitive to platform vibrations.

Su, Edward J.; Prentiss, Mara G. [Harvard University Department of Physics, Cambridge, Massachusetts 02138 (United States); Wu Saijun [Harvard University Department of Physics, Cambridge, Massachusetts 02138 (United States); Harvard University School of Engineering and Applied Science, Cambridge, Massachusetts 02138 (United States)

2010-04-15

8

Finding New Thermoelectric Compounds Using Crystallographic Data: Atomic Displacement Parameters  

SciTech Connect

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.

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

1999-08-29

9

On the Origin of Large Interstitial Clusters in Displacement Cascades  

SciTech Connect

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.

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

2010-01-01

10

A new iterative process for accurate analysis of displaced atoms from channeling Rutherford backscattering spectrometry  

Microsoft Academic Search

We have developed an iterative process to distinguish the yield contribution of the channeled He ions directly backscattered by displaced atoms and the yield contribution from the dechanneled He ions backscattered by lattice displaced atoms in channeling Rutherford backscattering spectrometry (RBS). The iterative process is able to accurately calculate the dechanneled fraction, the directly backscattered fraction and the dechanneling cross-section.

Lin Shao; Y. Q. Wang; M. Nastasi

2006-01-01

11

Voltage-dependent Membrane Displacements Measured by Atomic Force Microscopy  

PubMed Central

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.

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

1998-01-01

12

Retrieval of the atomic displacements in the crystal from the coherent X-ray diffraction pattern.  

PubMed

The retrieval of spatially resolved atomic displacements is investigated via the phases of the direct(real)-space image reconstructed from the strained crystal's coherent X-ray diffraction pattern. It is demonstrated that limiting the spatial variation of the first- and second-order spatial displacement derivatives improves convergence of the iterative phase-retrieval algorithm for displacements reconstructions to the true solution. This approach is exploited to retrieve the displacement in a periodic array of silicon lines isolated by silicon dioxide filled trenches. PMID:24971974

Minkevich, A A; Köhl, M; Escoubas, S; Thomas, O; Baumbach, T

2014-07-01

13

Intrinsic Noise Properties of Atomic Point Contact Displacement Detectors  

Microsoft Academic Search

We measure the noise added by an atomic point contact operated as a\\u000adisplacement detector. With a microwave technique, we increase the measurement\\u000aspeed of atomic point contacts by a factor of 500. The measurement is then fast\\u000aenough to detect the resonant motion of a nanomechanical beam at frequencies up\\u000ato 60 MHz and sensitive enough to observe the

N. E. Flowers-Jacobs; D. R. Schmidt; K. W. Lehnert

2007-01-01

14

Calculations of dynamical properties of skutterudites: thermal conductivity, thermal expansivity and atomic mean square displacement  

SciTech Connect

While the thermal conductivity of the filled skutterudites has been of great interest it had not been calculated within a microscopic theory. Here a central force, Guggenheim-McGlashen, model with parameters largely extracted from first-principles calculations and from spectroscopic data, specific to LaFe{sub 4}Sb{sub 12} or CoSb{sub 3}, is employed in a Green-Kubo/molecular dynamics calculation of thermal conductivity as a function of temperature. We find that the thermal conductivity of a filled solid is more than a factor of two lower than that of an unfilled solid, assuming the 'framework' interatomic force parameters are the same between filled and unfilled solids, and that this decrease is almost entirely due to the cubic anharmonic interaction between filling and framework atoms. In addition, partially as a test of our models, we calculate thermal expansivity and isotropic atomic mean-square displacements using both molecular dynamics and lattice dynamics methods. These quantities are in reasonable agreement with experiment, increasing our confidence in the anharmonic parameters of our models. We also find an anomalously large filling-atom mode Gruneisen parameter that is apparently observed for a filled skutterudite and is observed in a clathrate.

Bernstein, Noam [Naval Research Laboratory, Washington, D.C.; Feldman, J. L. [Naval Research Laboratory, Washington, D.C.; Singh, David J [ORNL

2010-01-01

15

Intrinsic Noise Properties of Atomic Point Contact Displacement Detectors  

Microsoft Academic Search

By coupling an atomic point contact (APC) to a nanomechanical beam, we measure the noise properties of an APC, an object which is the basis of scanning tunneling microscopy and is used to create electrical contact to single molecules. Using a microwave technique, we detect the resonant motion of the nanomechanical beam at frequencies up to 200 MHz. This measurement

N. E. Flowers-Jacobs; K. W. Lehnert

2007-01-01

16

Stressed State of Slightly Sloping Rotational Shells Under Large Displacements.  

National Technical Information Service (NTIS)

The problem of the stressed state of slightly sloping shells of rotation under high degrees of displacement is reduced to the integration of Karman equations under corresponding boundary conditions. These equations are solved by the small parameter method...

Y. F. Kayuk

1970-01-01

17

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

SciTech Connect

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.

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

18

Threshold displacement and interstitial-atom formation energies in Ni sub 3 Al  

SciTech Connect

Threshold displacement energies for atomic displacements along {l angle}110{r angle}, {l angle}100{r angle} and {l angle}111{r angle} directions, and formation enthalpies of several symmetric interstitial atom configurations were calculated for Ni{sub 3}Al by computer simulation using embedded atom method'' potentials. The Ni-Ni(100) dumbbell in the plane containing only Ni atoms has the lowest interstitial-atom enthalpy although the enthalpies of other configurations are similar. Interstitial configurations involving Al atoms all have much higher enthalpies. The anisotropy of the threshold energies in Ni{sub 3}Al is similar to pure metals and no significant difference in threshold energy was observed for {l angle}110{r angle} replacement chains in rows containing all Ni atoms or alternating Ni-Al atoms. Various metastable interstitial atom configurations were observed, including crowd-ions. In addition, the spontaneous recombination volume for some configurations can be much smaller than in pure metals. The consequences of these results for radiation induced segregation and amorphization {ital are} {ital discussed}.

Caro, A.; Victoria, M. (Paul Scherrer Institute, CH-5232 Villingen (Switzerland)); Averback, R.S. (Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL (USA))

1990-07-01

19

Atomic physics using large electrostatic accelerators  

SciTech Connect

This article surveys some areas of atomic physics using large electro-static accelerators. Brief overviews of ion-atom collisions and ion-solid collisions are followed by a classified listing of recent paper. A single line, correlated electron ion recombination, is chosen to show the recent development of techniques to study various aspects of this phenomenon. 21 refs., 11 figs., 1 tab.

Datz, S.

1989-01-01

20

Development of the ENDF/B-VI Atom Displacement Cross Sections for Iron  

SciTech Connect

The atom displacement (dpa) cross sections for iron given in the ASTM Standard Practice E6 693 are based on the data from ENDF/B-IV the cross sections have been changed considerably. In particular for iron, ENDF/B-VI gives cross-section evaluations for the individual isotopes with more forward-directed inelastic scattering, and reduced magnitude of the inelastic scattering at high energies. This report provides the displacement cross sections for iron generated from the ENDF/B-VI data and documents the procedure used to calculate the new dpa cross sections.

Remec, I.; White, J.E.

1999-06-01

21

Dependence of irradiation creep on temperature and atom displacements in 20% cold worked type 316 stainless steel  

Microsoft Academic Search

Irradiation creep studies with pressurized tubes of 20 percent cold worked Type 316 stainless steel were conducted in EBR-2. Results showed that as atom displacements are extended above 5 dpa and temperatures are increased above 375°C, the irradiation induced creep rate increases with both increasing atom displacements and increasing temperature. The stress exponent for irradiation induced creep remained near unity.

1976-01-01

22

Mean square atomic displacements of LaFe4Sb12  

NASA Astrophysics Data System (ADS)

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).

Feldman, Joseph; Singh, David

2005-03-01

23

Large area light-pulse atom interferometry  

PubMed

We report the experimental demonstration of a large area atom interferometer based on extended sequences of light pulses. We characterize the interferometer through measurement of the acceleration due to gravity and demonstrate a threefold enhancement in intrinsic acceleration sensitivity. The technique is applicable to many atom interferometer configurations, including those used for measurement of rotations, gravity gradients, and Planck's over 2pi/m. PMID:11082580

McGuirk; Snadden; Kasevich

2000-11-20

24

Dynamic Characteristics of a Hydraulic Amplification Mechanism for Large Displacement Actuators Systems  

PubMed Central

We have developed a hydraulic displacement amplification mechanism (HDAM) and studied its dynamic response when combined with a piezoelectric actuator. The HDAM consists of an incompressible fluid sealed in a microcavity by two largely deformable polydimethylsiloxane (PDMS) membranes. The geometry with input and output surfaces having different cross-sectional areas creates amplification. By combining the HDAM with micro-actuators, we can amplify the input displacement generated by the actuators, which is useful for applications requiring large deformation, such as tactile displays. We achieved a mechanism offering up to 18-fold displacement amplification for static actuation and 12-fold for 55 Hz dynamic actuation.

Arouette, Xavier; Matsumoto, Yasuaki; Ninomiya, Takeshi; Okayama, Yoshiyuki; Miki, Norihisa

2010-01-01

25

Ultrahigh-resolution study of protein atomic displacement parameters at cryotemperatures obtained with a helium cryostat.  

SciTech Connect

Two X-ray data sets for a complex of human aldose reductase (h-AR) with the inhibitor IDD 594 and the cofactor NADP(+) were collected from two different parts of the same crystal to a resolution of 0.81 A at 15 and 60 K using cold helium gas as cryogen. The contribution of temperature to the atomic B values was estimated by comparison of the independently refined models. It was found that although being slightly different for different kinds of atoms, the differences (deltaB) in the isotropic equivalents B of atomic displacement parameters (ADPs) were approximately constant (about 1.7 A(2)) for well ordered atoms as the temperature was increased from 15 to 60 K. The mean value of this difference varied according to the number of non-H atoms covalently bound to the parent atom. Atoms having a B value of higher than 8 A(2) at 15 K showed much larger deviations of deltaB from the average value, which might reflect partial occupancy of atomic sites. An analysis of the anisotropy of ADPs for individual atoms revealed an increase in the isotropy of ADPs with the increase of the temperature from 15 to 60 K. In a separate experiment, a 0.93 A resolution data set was collected from a different crystal of the same complex at 100 K using cold nitrogen as a cryogen. The effects of various errors on the atomic B values were estimated by comparison of the refined models and the temperature-dependent component was inferred. It was found that both decreasing the data redundancy and increasing the resolution cutoff led to an approximately constant increase in atomic B values for well ordered atoms.

Petrova, T.; Ginell, S.; Mitschler, A.; Hazemann, I.; Schneider, T.; Cousido, A.; Lunin, V.; Joachimiak, A.; Podjarny, A,; Biosciences Division; Russian Academy of Sciences; IGBMC; Inst. of Molecular Oncology

2006-01-01

26

102?k large area atom interferometers.  

PubMed

We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102?k). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves. PMID:22026831

Chiow, Sheng-wey; Kovachy, Tim; Chien, Hui-Chun; Kasevich, Mark A

2011-09-23

27

Cusp displacement at the magnetopause for large IMF Y component  

NASA Technical Reports Server (NTRS)

The magnetic field orientation just earthward of the dayside magnetopause from 95 ISEE and 11 HEOS crossings with /By/ greater than /Bz/ in the adjacent magnetosheath indicate a statistically significant-1-earth-radius shift of the cusps toward dawn (dusk) in the Northern Hemisphere and dusk (dawn) in the Southern Hemisphere for positive (negative) By. This small shift near the magnetopause and the contrasting large shifts of some reported ionospheric cusp signatures are explained in terms of a finite thickness magnetopause model through which the cusps shift gradually from the inner to the outer edge.

Crooker, N. U.; Berchem, J.; Russell, C. T.

1987-01-01

28

Atomic force microscope cantilevers as encoder for real-time displacement measurements  

NASA Astrophysics Data System (ADS)

We have investigated the use of atomic force microscope (AFM) cantilevers as encoder for real-time high-resolution displacement measurements. Mathematical derivations show that two AFM cantilevers signals are needed for real-time forward and backward displacement measurements in any planar direction and in x- or y-axis direction respectively when two are paired with a 1D sinusoidal grating. Tuning-fork (TF) cantilevers are the best choice among AFM cantilevers for the setup of a multi-cantilever encoder head. During the study an AFM head with up to three TF cantilevers as the encoder has been designed and built. The system was experimentally tested for its performance and feasibility of realtime displacement measurements in x- or y- axis by using two cantilevers. To achieve a correct reading the distance between two cantilever tips is preset in such a way that the two 1D sinusoidal grating position-encoded signals have a quadrature phase shift form. The decoding algorithm is based on directly unwrapping of the phase from the signals in real-time. Cross-correlation filtering and differentiation process of two encoded signals could be applied to suppress the noise and to reduce the offset and tilt of the encoded signals and by this allows a successful implementation of real-time displacement measurements.

Chen, Xiaomei; Wolff, Helmut; Koenders, Ludger

2012-05-01

29

Effects of Atomic Displacements in Guinier-Preston Zone of Al-Zn Alloy on Channeling of Protons  

Microsoft Academic Search

The atomic displacements in the spherical G-P zones precipitated in an Al-Zn single crystal are studied by analyzing the backscattered energy spectra of high energy protons. The analysis is carried out on the basis of the displaced atom model proposed by Merz and Gerold. The results obtained from the analysis on direct-scattering show that the values of distortion constant are

Teruo Sakurai

1973-01-01

30

Total Lagrangian Formulation for the Large Displacement Analysis of Rectangular Plates.  

National Technical Information Service (NTIS)

In this reprint, a method for the non-linear dynamic analysis of rectangular plates that undergo large rigid body motions and small elastic deformations is presented. The large rigid body displacement of the plate is defined by the translation and rotatio...

B. Chang A. A. Shabana

1990-01-01

31

Stratification of welding fumes and grinding particles in a large factory hall equipped with displacement ventilation.  

PubMed

The purpose of the study was to investigate the performance of displacement ventilation in a large factory hall where large components of stainless steel for paper, pulp and chemical industries were manufactured. The performance of displacement ventilation was evaluated in terms of concentration distributions of welding fumes and grinding particles, flow field of the supply air and temperature distributions. Large differences in vertical stratification patterns between hexavalent chromium (Cr(VI)) and other particulate contaminants were observed. The concentration of Cr(VI) was notably lower in the zone of occupancy than in the upper part of the factory hall, whereas the concentrations of total airborne particles and trivalent chromium (Cr(III)) were higher in the occupied zone than in the upper zone. The stratification of Cr(VI) had the same tendency as the air temperature stratification caused by the displacement flow field. PMID:11513796

Niemelä, R; Koskela, H; Engström, K

2001-08-01

32

Parallel interactions at large horizontal displacement in pyridine-pyridine and benzene-pyridine dimers.  

PubMed

A study of crystal structures from the Cambridge Structural Database (CSD) and DFT calculations reveals that parallel pyridine-pyridine and benzene-pyridine interactions at large horizontal displacements (offsets) can be important, similar to parallel benzene-benzene interactions. In the crystal structures from the CSD preferred parallel pyridine-pyridine interactions were observed at a large horizontal displacement (4.0-6.0 Å) and not at an offset of 1.5 Å with the lowest calculated energy. The calculated interaction energies for pyridine-pyridine and benzene-pyridine dimers at a large offset (4.5 Å) are about 2.2 and 2.1 kcal mol(-1), respectively. Substantial attraction at large offset values is a consequence of the balance between repulsion and dispersion. That is, dispersion at large offsets is reduced, however, repulsion is also reduced at large offsets, resulting in attractive interactions. PMID:23090910

Ninkovi?, Dragan B; Andri?, Jelena M; Zari?, Snežana D

2013-01-14

33

Novel bounce drive actuator for large step displacement and low friction micromotor applications  

Microsoft Academic Search

This investigation presents an innovative bounce drive actuator (BDA) to develop a rotary micromotor with low friction and large step displacement. The BDA device has a shorter plate and wider bushing designs than the conventional scratch drive actuator (SDA), resulting in a new electrostatic bounceback driving mechanism and a larger step size of motion. The innovative bounce actuating mechanism considerably

I-Yu Huang; Guan-Ming Chen; Yen-Chi Lee; Alex Horng

2008-01-01

34

Stokes flow in an elastic tube - a large-displacement fluid-structure interaction problem  

Microsoft Academic Search

Viscous flow in elastic (collapsible) tubes is a large-displacement fluid-structure interaction problem frequently encountered in biomechanics. This paper presents a robust and rapidly converging procedure for the solution of the steady three-dimensional Stokes equations, coupled to the geometrically non-linear shell equations which describe the large deformations of the tube wall. The fluid and solid equations are coupled in a segregated

Matthias Heil

1998-01-01

35

Shakedown and steady-state responses of elastic-plastic solids in large displacements  

Microsoft Academic Search

Elastic-perfectly plastic solids (or structures) subjected to loads quasi-statically varying within a specified domain are addressed in the framework of large displacements and the additive strain decomposition rule. On the ground of Drucker's principle of stability in the large, an appropriate stability requisite (called D-stability) is formulated as the positive definiteness property of a specific functional, sum of the second

Castrenze Polizzotto; Guido Borino

1996-01-01

36

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

PubMed

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

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

2012-08-01

37

MD simulation of atomic displacement cascades in Fe-10 at.%Cr binary alloy  

NASA Astrophysics Data System (ADS)

Molecular dynamics simulation of atomic displacement cascades up to 20 keV has been performed in Fe-10 at.%Cr binary alloy at a temperature of 600 K. The N-body interatomic potentials of Finnis-Sinclair type were used. According to the obtained results the dependence of "surviving" defects amount is well approximated by power function that coincides with other researchers' results. Obtained cascade efficiency for damage energy in the range from 10 to 20 keV is ?0.2 NRT that is slightly higher than for pure ?-Fe. In post-cascade area Cr fraction in interstitials is in range 2-5% that is essentially lower than Cr content in the base alloy. The results on size and amount of vacancy and interstitial clusters generated in displacement cascades are obtained. For energies of 2 keV and higher the defect cluster average size increases and it is well approximated by a linear dependence on cascade energy both for interstitials and vacancies.

Tikhonchev, M.; Svetukhin, V.; Kadochkin, A.; Gaganidze, E.

2009-12-01

38

Modeling of XFEL induced ionization and atomic displacement in protein nanocrystals  

NASA Astrophysics Data System (ADS)

X-ray free-electron lasers enable high-resolution imaging of biological materials by using short enough pulses to outrun many of the effects of radiation damage. Experiments conducted at the LCLS have obtained diffraction data from single particles and protein nanocrystals at doses to the sample over 3 GGy. The details of the interaction of the X-ray FEL pulse with the sample determine the limits of this new paradigm for imaging. Recent studies suggest that in the case of crystalline samples, such as protein nanocrystals, the atomic displacements and loss of bound electrons in the crystal (due to the high X- ray intensity) has the effect of gating the diffraction signal, and hence making the experiment less radiation sensitive. Only the incident photon intensity in the first part of the pulse, before the Bragg diffraction has died out, is relevant to acquiring signal and the rest of the pulse will mainly contribute to a diffuse background. In this work we use a plasma based non-local thermodynamic equilibrium code to explore the displacement and the ionization of a protein nanocrystal at various X-ray wavelengths and intensities.

Caleman, Carl; Tîmneanu, Nicusor; Martin, Andrew V.; White, Thomas A.; Scott, Howard A.; Barty, Anton; Aquila, Andrew; Chapman, Henry N.

2012-10-01

39

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

PubMed Central

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.

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

2012-01-01

40

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

NASA Astrophysics Data System (ADS)

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 to produce a displacement in the y-direction only. In other two types of actuators (the deflector and the contractor), the constraint beams are positioned parallel to the active arms. When the constraint beams are on the inside of the active arms, the actuator produces an outward deflection in the y-direction. When they are on the outside of the active arms, the actuator produces an inward contraction. Analytical model and finite element analysis were used to simulate the performances. It showed that at a constant temperature, analytical model is sufficient to predict the displacement of these devices. The displacements are all proportional to the temperature and the number of the chevron sections. A two-mask process is under development to fabricate these devices, using Si3N4 as the insulator beams, and electroplated Ni as the conductive beams.

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

2005-07-01

41

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

Microsoft Academic Search

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

Jeong Sam Han; Jong Soo Ko; Jan G Korvink

2004-01-01

42

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

PubMed

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

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

2013-08-22

43

Neutron diffraction analysis of atomic displacements in ?-Pu-Ga alloys upon long-term self-irradiation  

NASA Astrophysics Data System (ADS)

The process of self-irradiation of a Pu-Ga alloy has been studied by the neutron-diffraction method with the determination of the crystal structure and root-mean-square atomic displacements < u 2> (from the data on the Debye-Waller factor). The analysis was carried out at room temperature on the sample with an fcc structure prepared on the basis of a Pu242 isotope feebly absorbing neutrons, in which a quickly decaying Pu238 isotope (1.4 at %) was added to intensify self-irradiation processes; this accelerated the aging processes by four times and allowed achieving the maximum equivalent self-irradiation time of ˜23.5 years. The fcc structure was preserved during all this time interval. An analysis of the small-angle neutron scattering has demonstrated that the sample also contained precipitates with a size of a few hundreds of microns, which did not change during the aging. A change in < u 2> (due to static displacements) occurs in two stages, i.e., a relatively rapid growth (by about 50%) during the first 5-6 years of self-irradiation, and a slow decrease in the subsequent 6-23 equivalent years to nearly the magnitude that exceeds the initial value by ˜20%. The latter stage can be explained by the sinking of continuously generated point defects to helium bubbles and dislocations loops accumulating with time. The extrapolation of the decrease in < u 2> to large aging times demonstrates that if the mechanism of point-defect accumulation initiated at the first stage of the self-irradiation does not change with time, the growth of < u 2> will disappear by about 50 years of equivalent time of self-irradiation.

Blanter, M. S.; Glazkov, V. P.; Laushkin, A. V.; Orlov, V. K.; Somenkov, V. A.; Shushunov, M. N.

2012-06-01

44

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

SciTech Connect

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 PKA mass has a major effect on cascade damage while the interaction potential has little if any. Second, the total number of point defects produced in a cascade decreases with increasing PKA mass. This fact is not accounted for in models used conventionally for estimating damage. Third, interstitial loops of <111> type and both vacancy and interstitial loops of <100> type are formed, the latter being observed in MD simulation for the first time. The probability of <100> loop appearance increases with increasing PKA mass as well as energy. Finally, there is a correlation between production of large vacancy and interstitial clusters in the same cascade.

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

2008-01-01

45

Large displacement distal chevron osteotomy for the correction of hallux valgus deformity.  

PubMed

In order to assess outcomes and complications, a retrospective study of 38 bunionectomy cases with large displacement distal chevron osteotomy (greater than or equal to 40% lateral translation) for hallux valgus was performed. Follow-up ranged from 12 to 130 months (average, 31 months). Subjective analysis consisting of the American Orthopedic Foot and Ankle Society (AOFAS) hallux metatarsophalangeal-interphalangeal scale was performed. Preoperative and postoperative radiographic intermetatarsal (IM) angles and hallux abductus angles were measured and compared. The average postoperative AOFAS score was 93.5. The average preoperative IM angle was 15.03 degrees (range 8 degrees-24 degrees) and the average postoperative IM angle was 4.84 degrees (range, -1 degree-11 degrees). The average preoperative hallux abductus angle was 29.39 degrees (range, 16 degrees-53 degrees) compared to the average postoperative hallux abductus angle of 11.39 degrees (range, 2 degrees-28 degrees). It was found that an average lateral translation of 9.8 mm was able to achieve a relative change of the IM angle of 10 degrees. Evidence is presented that supports the fact that large displacement distal chevron osteotomies can be safely performed for the correction of metatarsus primus varus greater than 15 degrees associated with hallux valgus. PMID:12194510

Stienstra, John J; Lee, Julie Ann; Nakadate, Dean T

2002-01-01

46

Modified Fabry-Perot interferometer for displacement measurement in ultra large measuring range.  

PubMed

Laser interferometers have demonstrated outstanding measuring performances for high precision positioning or dimensional measurements in the precision industry, especially in the length measurement. Due to the non-common-optical-path structure, appreciable measurement errors can be easily induced under ordinary measurement conditions. That will lead to the limitation and inconvenience for in situ industrial applications. To minimize the environmental and mechanical effects, a new interferometric displacement measuring system with the common-optical-path structure and the resistance to tilt-angle is proposed. With the integration of optomechatronic modules in the novel interferometric system, the resolution up to picometer order, high precision, and ultra large measuring range have been realized. For the signal stabilization of displacement measurement, an automatic gain control module has been proposed. A self-developed interpolation model has been employed for enhancing the resolution. The novel interferometer can hold the advantage of high resolution and large measuring range simultaneously. By the experimental verifications, it has been proven that the actual resolution of 2.5 nm can be achieved in the measuring range of 500 mm. According to the comparison experiments, the maximal standard deviation of the difference between the self-developed Fabry-Perot interferometer and the reference commercial Michelson interferometer is 0.146 ?m in the traveling range of 500 mm. With the prominent measuring characteristics, this should be the largest dynamic measurement range of a Fabry-Perot interferometer up till now. PMID:23742530

Chang, Chung-Ping; Tung, Pi-Cheng; Shyu, Lih-Horng; Wang, Yung-Cheng; Manske, Eberhard

2013-05-01

47

Large Reference Displacement Analysis of Composite Plates. Part 1. Finite Element Formulation. (Reannouncement with New Availability Information).  

National Technical Information Service (NTIS)

This investigation concerns itself with the dynamic analysis of thin, laminated composite plates consisting of layers of orthotropic laminae that undergo large arbitrary rigid body displacements and small elastic deformations. A non-linear finite element ...

J. M. Kremer A. A. Shabana G. E. Widera

1993-01-01

48

GPS Seismology: Using Precise Point Positioning for Resolving Surface Wave Displacements from Large Earthquakes  

NASA Astrophysics Data System (ADS)

High-rate continuous GPS data can provide direct, high-quality measurements of surface wave displacements generated by large earthquakes (Larson et al., 2003; Bock et al., 2004; Larson, 2009). To achieve high precision, differential positioning is often used in the GPS analysis strategy with distant reference stations held fixed. In this presentation, we examine the use of the Precise Point Positioning (PPP) technique to estimate epoch-by-epoch positions at single stations. Specifically, we use the PPP software developed by Natural Resources Canada (Heroux and Kouba, 2001) to analyze high-rate (5 Hz) GPS data collected at stations of the Plate Boundary Observatory (PBO) in southern California at the time of the M7.2 El Mayor-Cucapah Earthquake of April 4, 2010. The hypocenter for this earthquake was located in northern Baja California, approximately 50 km south of Mexicali on the US-Mexico border, at a depth of ~10 km. Large horizontal displacements were observed at a number of PBO GPS sites, with the largest peak-to-peak displacements exceeding 90 cm in the east-west component for 10-sec period waves observed at El Centro, CA (P496), located about 70 km northeast of the epicenter. The PPP technique clearly resolved surface waves with 1 to 2 cm amplitudes at sites more than 800 km away from the epicenter, illustrating that surface waves eventually reach even distant reference sites within the period of interest and can thereby introduce artifacts for differential GPS positioning. Fine-tuning of PPP methodology revealed the following: 1) Since the quality of a PPP solution will not be optimal until the carrier phase ambiguities have converged (tens of minutes), it is best to begin the analyses well before the arrival of seismic waves. To reduce computations, the data for this convergence period need not be high-rate; 2) The use of 5-second precise satellite clock sampling instead of the nominal 30-second clock sampling minimized clock interpolation errors and resulted in improved solutions; 3) Allowing some slow variation in the zenith tropospheric delay over periods of minutes appears to improve the vertical component solution. We conclude that high-rate (5 Hz) PPP can augment observations of ground displacements with periods of 1 s or longer at a resolution of 1 to 2 cm at single stations, both in the near and far fields, avoiding potential bias introduced by motions at a reference site. This makes high-rate PPP analysis of GPS data a useful technique for quantifying longer period ground motions of engineering interest.

Dragert, H.; Henton, J. A.; Lahaye, F.; Kouba, J.; Larson, K. M.; Rogers, G. C.

2010-12-01

49

X-ray study of atomic displacements in Nb/sub 3/Sn induced by radiation damage  

SciTech Connect

We have performed detailed x-ray determinations of the crystal structure of Nb/sub 3/Sn films as a function of /sup 4/He particle radiation damage. It is found that, in addition to antisite defects, substantial displacements (-0.2 A) of both the Nb and Sn atoms must be invoked to explain the data. We suggest the data are consistent with a transition from covalent to metallic bonding along the Nb chains.

Burbank, R.D.; Dynes, R.C.; Poate, J.M.

1979-09-01

50

Estimated H-atom anisotropic displacement parameters: a comparison between different methods and with neutron diffraction results.  

PubMed

Anisotropic displacement parameters (ADPs) are compared for H atoms estimated using three recently described procedures, both among themselves and with neutron diffraction results. The results convincingly demonstrate that all methods are capable of giving excellent results for several benchmark systems and identify systematic discrepancies for several atom types. A revised and extended library of internal H-atom mean-square displacements is presented for use with Madsen's SHADE web server [J. Appl. Cryst. (2006), 39, 757-758; http://shade.ki.ku.dk], and the improvement over the original SHADE results is substantial, suggesting that this is now the most readily and widely applicable of the three approximate procedures. Using this new library--SHADE2--it is shown that, in line with expectations, a segmented rigid-body description of the heavy atoms yields only a small improvement in the agreement with neutron results. The SHADE2 library, now incorporated in the SHADE web server, is recommended as a routine procedure for deriving estimates of H-atom ADPs suitable for use in charge-density studies on molecular crystals, and its widespread use should reveal remaining deficiencies and perhaps overcome the inherent bias in the majority of such studies. PMID:18560163

Munshi, Parthapratim; Madsen, Anders Ø; Spackman, Mark A; Larsen, Sine; Destro, Riccardo

2008-07-01

51

Nonlinear finite element formulation for the large displacement analysis in multibody system dynamics  

NASA Technical Reports Server (NTRS)

A total Lagrangian finite element formulation for the deformable bodies in multibody mechanical systems that undergo finite relative rotations is developed. The deformable bodies are discretized using finite element methods. The shape functions that are used to describe the displacement field are required to include the rigid body modes that describe only large translational displacements. This does not impose any limitations on the technique because most commonly used shape functions satisfy this requirement. The configuration of an element is defined using four sets of coordinate systems: Body, Element, Intermediate element, Global. The body coordinate system serves as a unique standard for the assembly of the elements forming the deformable body. The element coordinate system is rigidly attached to the element and therefore it translates and rotates with the element. The intermediate element coordinate system, whose axes are initially parallel to the element axes, has an origin which is rigidly attached to the origin of the body coordinate system and is used to conveniently describe the configuration of the element in undeformed state with respect to the body coordinate system.

Rismantab-Sany, J.; Chang, B.; Shabana, A. A.

1989-01-01

52

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

PubMed Central

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.

Guelpa, Valerian; Laurent, Guillaume J.; Sandoz, Patrick; Zea, July Galeano; Clevy, Cedric

2014-01-01

53

A metrological large range atomic force microscope with improved performance  

SciTech Connect

A metrological large range atomic force microscope (Met. LR-AFM) has been set up and improved over the past years at Physikalisch-Technische Bundesanstalt (PTB). Being designed as a scanning sample type instrument, the sample is moved in three dimensions by a mechanical ball bearing stage in combination with a compact z-piezostage. Its topography is detected by a position-stationary AFM head. The sample displacement is measured by three embedded miniature homodyne interferometers in the x, y, and z directions. The AFM head is aligned in such a way that its cantilever tip is positioned on the sample surface at the intersection point of the three interferometer measurement beams for satisfying the Abbe measurement principle. In this paper, further improvements of the Met. LR-AFM are reported. A new AFM head using the beam deflection principle has been developed to reduce the influence of parasitic optical interference phenomena. Furthermore, an off-line Heydemann correction method has been applied to reduce the inherent interferometer nonlinearities to less than 0.3 nm (p-v). Versatile scanning functions, for example, radial scanning or local AFM measurement functions, have been implemented to optimize the measurement process. The measurement software is also improved and allows comfortable operations of the instrument via graphical user interface or script-based command sets. The improved Met. LR-AFM is capable of measuring, for instance, the step height, lateral pitch, line width, nanoroughness, and other geometrical parameters of nanostructures. Calibration results of a one-dimensional grating and a set of film thickness standards are demonstrated, showing the excellent metrological performance of the instrument.

Dai, Gaoliang; Wolff, Helmut; Pohlenz, Frank; Danzebrink, Hans-Ulrich [Physikalisch-Technische Bundesanstalt (PTB), 38116 Braunschweig (Germany)

2009-04-15

54

Ion-channeling study of anomalous atomic displacements at the superconducting transition in high-T sub c materials  

SciTech Connect

Ion channeling along the (001) direction in high-quality single crystals of (Y/Er)Ba{sub 2}Cu{sub 3}O{sub 7-x} revealed an abrupt change in displacements in the a-b plane of the Cu and O atoms at the superconducting transition, {Tc}; normal Debye-like'' vibrations were found for the Y/Er and Ba atoms. The anomalous change in Cu-O displacements was found to shift directly with stoichiometry-induced changes in {Tc}, implying a direct link between the observed phonon anomaly and the superconducting transition. Recent measurements of ion-channeling along the (001) axis in (Bi{sub 1.7}Pb{sub 0.3})Sr{sub 2}Ca{sub 1}Cu{sub 2}O{sub x} single-crystals revealed a similar change at {Tc}, suggesting that this phonon anomaly is a general feature of high-{Tc} superconductivity. In order to identify more specifically the crystallographic directions and displacement amplitudes associated with the anomalous phonon behavior, axial channeling scans using RBS, as well as characteristic x-ray production, were taken at several temperatures between 30 and 300K along the (301) and (331) directions of YBa{sub 2}Cu{sub 3}O{sub 7-x} single crystals. Twins present in the specimens, and the existing static atomic displacements present along these directions, caused the channeling to be poorer along these axes compared to the (001) direction. Also, a much stronger dependence of the minimum yield on depth was observed. However, since only one twin variant generally dominated over sufficiently wide areas of the specimens, reasonably good ({approximately}10%) minimum yields could be obtained along the appropriate (331) axis, and detwinned crystals produced good results along (301). 22 refs., 5 figs.

Rehn, L.E.; Sharma, R.P.; Baldo, P.M.

1990-06-01

55

Comparison of molecular dynamics and binary collision approximation simulations for atom displacement analysis  

NASA Astrophysics Data System (ADS)

Molecular dynamics (MD) and binary collision approximation (BCA) computer simulations are employed to study surface damage by single ion impacts. The predictions of BCA and MD simulations of displacement cascades in amorphous and crystalline silicon and BCC tungsten by 1 keV Ar+ ion bombardment are compared. Single ion impacts are studied at angles of 50°, 60° and 80° from normal incidence. Four parameters for BCA simulations have been optimized to obtain the best agreement of the results with MD. For the conditions reported here, BCA agrees with MD simulation results at displacements larger than 5 Å for amorphous Si, whereas at small displacements a difference between BCA and MD arises due to a material flow component observed in MD simulations but absent from a regular BCA approach due to the algorithm limitations. MD and BCA simulation results for crystalline W are found to be in a good agreement even at small displacements, while in crystalline Si there is some difference due to displacements in amorphous pockets.

Bukonte, L.; Djurabekova, F.; Samela, J.; Nordlund, K.; Norris, S. A.; Aziz, M. J.

2013-02-01

56

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

NASA Astrophysics Data System (ADS)

We compare the relative performance of monolithic and segregated (partitioned) solvers for large- displacement fluid structure 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 too expensive for use in large-scale problems. We demonstrate that monolithic solvers are competitive even for problems in which the fluid solid coupling is weak and, hence, the segregated solvers converge within a moderate number of iterations. The efficient monolithic solution of large-scale FSI problems requires the development of preconditioners for the iterative solution of the linear systems that arise during the solution of the monolithically coupled fluid and solid equations by Newton’s method. We demonstrate that recent improvements to oomph-lib’s FSI preconditioner result in mesh-independent convergence rates under uniform and non-uniform (adaptive) mesh refinement, and explore its performance in a number of two- and three-dimensional test problems involving the interaction of finite-Reynolds-number flows with shell and beam structures, as well as finite-thickness solids.

Heil, Matthias; Hazel, Andrew L.; Boyle, Jonathan

2008-12-01

57

Relaxation Methods Applied to Engineering Problems. VIIIA. Problems Relating to Large Transverse Displacements of Thin Elastic Plates  

Microsoft Academic Search

Small transverse displacements of a flat elastic plate are governed by a single linear equation, but large displacements entail stretching of the middle surface and consequent tensions, which interacting with the curvatures (i.e. by 'membrane effect') introduce non-linear terms into the conditions of equilibrium and so make those equations no longer independent. The second-order terms were formulated by von Karman

J. R. Green; R. V. Southwell

1945-01-01

58

Critical Displacement of Host-Atoms for Amorphization in Germanium Induced by Arsenic Implantation  

NASA Astrophysics Data System (ADS)

We evaluated quantitatively the germanium (Ge) displacement induced by arsenic (As) implantation as a function of the depth from the sample surface both in the amorphous and single-crystalline regions using 70Ge/\\text{natGe isotope superlattices (SLs). The profiles of 74Ge in the Ge isotope SLs were measured by secondary ion mass spectrometry and the sample structure along the depth was observed by cross-sectional transmission electron microscopy. The critical Ge displacement for amorphization induced by As implantation is found to be 0.75 nm, which is independent of the implantation doses. This value is 50% larger than 0.5 nm for Si.

Kawamura, Yoko; Shimizu, Yasuo; Oshikawa, Hiroyuki; Uematsu, Masashi; Haller, Eugene E.; Itoh, Kohei M.

2010-07-01

59

DYNAMICS OF ATOMIC DISPLACEMENT PROCESSES. II. INFLUENCE OF CRYSTAL LATTICE ON CASCADES  

Microsoft Academic Search

Dynamic calculations carried out on the basis of a manybody lattice ; model of alpha -iron indicate that 1) An actual cubic lattice (b.c.c. or ; f.c.c.) is highly anisotropic. The random model of radiation damage, which ; assumes that all directions are equivalent as far as displacement production is ; concerned, is inadequate in describing actual conditions. Cubic lattices

Erginsoy

1963-01-01

60

Lattice-dynamical evaluation of atomic displacement parameters for coesite from an empirical force field with implications on thermodynamic properties  

Microsoft Academic Search

Using empirical potentials derived from fitting the vibrational frequencies of a group of silicates and oxides (not including\\u000a the mineral under study), a Born-von Karman rigid-ion lattice-dynamical model has been applied to the whole Brillouin zone\\u000a in coesite. The atomic anisotropic displacement parameters (A.D.P.s) derived from accurate crystal-structure refinement at\\u000a room temperature and at 15 K agree very well with

T. Pilati; F. Demartin; C. M. Gramaccioli

1998-01-01

61

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

NASA Technical Reports Server (NTRS)

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.

Arya, Vinod K.; Halford, Gary R.

1994-01-01

62

Discordant paleomagnetic poles from the Canadian Coast Plutonic Complex: Regional tilt rather than large-scale displacement  

SciTech Connect

Stratigraphic, petrologic, and isotopic data indicate that parts of the Coast Plutonic Complex and the North Cascade Range have been tilted northeast-side-up by angles of {approximately}30{degree} about north-northwest-trending axes. These tilts can account for discordant paleomagnetic directions observed in mid-Cretaceous plutons from these regions without large-scale displacement relative to North America.

Butler, R.F.; Gehrels, G.E.; McClelland, W.C. (Univ. of Arizona, Tucson (USA)); May, S.R.; Klepacki, D. (Exxon Production Research Co., Houston, TX (USA))

1989-08-01

63

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

Microsoft Academic Search

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

Tetsuhiko Iizuka; Hiroyuki Fujita

1996-01-01

64

NONLINEAR BEHAVIOR OF PILE GROUP IN DRY SAND BASED ON LATERAL CYCLIC LOADING TESTS WITH LARGE DISPLACEMENT AMPLITUDE  

Microsoft Academic Search

Nonlinear effects of soil-structure interaction under strong ground motions should be considered in the seismic design. This paper presents the results of lateral cyclic loading test for pile groups in dry sand to investigate the nonlinear behavior of the soil-pile group interaction for large displacement range. The test parameters are the number of piles, the layout of pile groups, the

Hisatoshi KASHIWA; Takashi KURATA; Michito SHOJI; Yasuhiro HAYASHI; Keiichiro SUITA; Shuji TAMURA

65

Compact multi-physics models for large-displacement multilayer cantilevers in RF MEMS circuits, antennas and sensors  

Microsoft Academic Search

We demonstrate compact analytical multi-physics models that accurately predict the deformed shape of a variety of multilayer cantilevers and the associated electrical characteristics when employed in several practical sensor and RF applications. We pay particular attention to structures relying on large mechanical displacements in order to achieve the desired performance. Practical applications of these cantilevers are shown in several important

Jeong Il Kim

2008-01-01

66

Atomic displacement parameters for spessartine Mn3Al2Si3O12 and their lattice-dynamical interpretation.  

PubMed

A rigid-ion lattice-dynamical treatment accounts reasonably well for most of the atomic displacement parameters (ADPs) reported in the literature for a synthetic sample of spessartine Mn(3)Al(2)Si(3)O(12); the model accounts less well for the ADPs of the Mn atom. These results are similar to those obtained for the corresponding garnets pyrope Mg(3)Al(2)Si(3)O(12) and almandine Fe(3)Al(2)Si(3)O(12). The results are confirmed by a very good agreement of the lattice-dynamical estimates with the experimental values of the heat capacity that are currently available, as well as those of the Raman and infrared vibrational spectra. The anomalous behaviour of the Mn atom is reflected in the entropy values. As is the case for pyrope and almandine, here the agreement with the experimental results can be markedly improved if the existence of a low-temperature order-disorder transition concerning the Mn atom is considered. The lattice-dynamical estimates for all the atoms presented here do not agree with the corresponding ADPs obtained in a crystal structure refinement of a supposedly 'pure' natural sample from Elba. In turn, these experimental ADPs do not agree with those observed for the synthetic sample, thereby showing a physical difference; such a possibility is in agreement with recent observations by other authors, who found an unexpected fluorine content in several natural specimens of spessartine. Therefore, theoretical estimates of ADPs are reliable enough to point out unexpected situations if disagreement with the observed values occurs. PMID:12456974

Gramaccioli, Carlo Maria; Pilati, Tullio; Demartin, Francesco

2002-12-01

67

Application of Proving-Ring Technology to Measure Thermally Induced Displacements in Large Boreholes in Rock.  

National Technical Information Service (NTIS)

A strain-gauged proving-ring transducer was designed and deployed to measure small diametral displacements in 0.61-m diameter boreholes in rock. The rock surrounding the boreholes was previously heated by storage of spent nuclear fuel assemblies and measu...

W. C. Patrick N. L. Reactor T. R. Butkovich

1984-01-01

68

Atomic modulation functions and structure factors for displacively modulated, high-Tc Bi2Sr2CaCu2O8+delta  

Microsoft Academic Search

The high-temperature superconducting phase Bi2Sr2CaCu2O8+delta belongs to the class of modulated structures. Its structure can be described by a basic structure and an additional harmonic displacement field which is incommensurate with respect to the basic structure. High-resolution electron microscopy was used to determine the atomic sites in the unit cell. From this the displacement field could be determined for the

O. Eibl

1990-01-01

69

Atomic-Scale Simulation of Defect Cluster Formation in High-Energy Displacement Cascades in Zirconium.  

SciTech Connect

A systematic study of damage in high-energy cascades in Zr with primary knock-on-atom (PKA) energy up to 25 keV has been carried out by molecular dynamics (MD) over a temperature range from 100-600 K. The high number of simulations for each condition of temperature and energy has revealed the wide variety of defect clusters that can be created in cascades. Mobile or sessile, two-dimensional (2D) or three-dimensional (3D) clusters of both vacancy and interstitial type can be formed. The population statistics of clusters of each type and the fraction of vacancies and self-interstitial atoms (SIA) in clusters, were obtained, and their dependence on the temperature and PKA energy were investigated. Both vacancy and SIA clusters can be mobile. However, depending on their type, self-interstitial clusters exhibit one-dimensional, planar, or three-dimensional motions, whereas vacancy clusters of only one type can glide in one dimension only. We have also performed separate MD simulations of some SIA and vacancy clusters to study their thermal stability and possible transformations.

Voskoboinikov, Roman E [University of Liverpool; Osetskiy, Yury N [ORNL; Bacon, David J [University of Liverpool

2006-01-01

70

Electronic Ferroelectricity in a Molecular Crystal with Large Polarization Directing Antiparallel to Ionic Displacement  

NASA Astrophysics Data System (ADS)

Ferroelectric polarization of 6.3?Ccm-2 is induced by the neutral-to-ionic transition, upon which nonpolar molecules of electron donor tetrathiafulvalene (TTF) and acceptor p-chloranil (CA) are incompletely ionized to ±0.60e and dimerized along the molecular stacking chain. We find that the ferroelectric properties are governed by intermolecular charge transfer rather than simple displacement of static point charge on molecules. The observed polarization and poling effect on the absolute structural configuration can be interpreted in terms of electronic ferroelectricity, which not only exhibits antiparallel polarity to the ionic displacement but also enhances the polarization more than 20 times that of the point-charge model.

Kobayashi, Kensuke; Horiuchi, Sachio; Kumai, Reiji; Kagawa, Fumitaka; Murakami, Youichi; Tokura, Yoshinori

2012-06-01

71

Electronic ferroelectricity in a molecular crystal with large polarization directing antiparallel to ionic displacement.  

PubMed

Ferroelectric polarization of 6.3???C?cm(-2) is induced by the neutral-to-ionic transition, upon which nonpolar molecules of electron donor tetrathiafulvalene (TTF) and acceptor p-chloranil (CA) are incompletely ionized to ±0.60e and dimerized along the molecular stacking chain. We find that the ferroelectric properties are governed by intermolecular charge transfer rather than simple displacement of static point charge on molecules. The observed polarization and poling effect on the absolute structural configuration can be interpreted in terms of electronic ferroelectricity, which not only exhibits antiparallel polarity to the ionic displacement but also enhances the polarization more than 20 times that of the point-charge model. PMID:23003988

Kobayashi, Kensuke; Horiuchi, Sachio; Kumai, Reiji; Kagawa, Fumitaka; Murakami, Youichi; Tokura, Yoshinori

2012-06-01

72

An efficient solver for the fully coupled solution of large-displacement fluid–structure interaction problems  

Microsoft Academic Search

This paper is concerned with the fully coupled (‘monolithic’) solution of large-displacement fluid–structure interaction problems by Newton’s method. We show that block-triangular approximations of the Jacobian matrix, obtained by neglecting selected fluid–structure interaction blocks, provide good preconditioners for the solution of the linear systems with GMRES. We present an efficient approximate implementation of the preconditioners, based on a Schur complement

Matthias Heil

2004-01-01

73

Noise-Immune Conjugate Large-Area Atom Interferometers  

Microsoft Academic Search

We present a pair of simultaneous conjugate Ramsey-Borde atom interferometers (SCI) using large (20\\\\hbar k)-momentum transfer (LMT) beam splitters, where \\\\hbar 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\\\\hbar k by a factor of 2,500. Among applications,

Sheng-Wey Chiow; Steven Chu; Holger Mueller

2009-01-01

74

Improvement in the Identification of a Crack Tip Echo in Ultrasonic Inspection using Large Displacement Ultrasound Transmission  

NASA Astrophysics Data System (ADS)

As an improvement in the imaging technique for the low S/N ratio of crack tip echo in ultrasonic inspection, we developed the Subharmonic Phased Array Crack Evaluation (SPACE) system. Although the pulser of conventional SPACE can generate large, over tens of nm, displacement ultrasound at a crack, it is effective only for closed cracks and not effective for most industrial cracks. For general use of the SPACE system in industrial inspection, we need to develop larger displacement ultrasound incidence equipment considering crack openings of the order of several nm to sub ?m. In this study, we developed a high voltage excitation SPACE and larger amplitude ultrasound incident to a crack using a high voltage proof transducer. The suitability of the developed system was investigated using typical models of cracks.

Mihara, T.; Ishida, H.

2014-06-01

75

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

PubMed

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

Park, Jin Y; Lee, Jeong Wan

2012-01-01

76

Determination of the Shear Buckling Load of a Large Polymer Composite I-Section Using Strain and Displacement Sensors  

PubMed Central

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.

Park, Jin Y.; Lee, Jeong Wan

2012-01-01

77

Nonrelativistic variationally optimized exchange potentials for Ne-like atomic ions having large atomic number  

SciTech Connect

In an earlier study, the exchange energy density {epsilon}{sub x}(r) has been calculated analytically for Ne-like atomic ions in the nonrelativistic limit of large atomic number Z. Here, though now by numerical methods based on the optimized exchange potential approximation, corresponding results are obtained for V{sub x}(r) for such ten-electron ions at large Z. The approach to the bare Coulomb limiting form of the 1/Z expansion is considered in some detail, as are corrections to the Slater potential V{sub x}{sup Sl}(r), given in terms of the exchange energy density and ground-state density {rho}(r) by 2{epsilon}{sub x}(r)/{rho}(r)

Howard, I.A. [Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp (Belgium); March, N.H. [Department of Physics, University of Antwerp, Groenenborgerlaan 171, Antwerp (Belgium); Oxford University, Oxford (United Kingdom); Talman, J.D. [Department of Applied Mathematics, University of Western Ontario, London, Ontario (Canada)

2003-10-01

78

A reduced-order model of squeeze-film damping for deformable micromechanical structures including large displacement effects  

NASA Astrophysics Data System (ADS)

We present a reduced-order model of the squeezed-film damping phenomenon which is valid for flexible structures, large displacements (with respect to the gap) and small pressure variations (with respect to the ambient pressure). This reduced-order model is obtained by transforming the Reynolds equation into a form more amenable to modal projection techniques. Our approach is validated by comparison to simulated and experimental data. Moreover, we show that in several practical cases the 'small pressure' hypothesis is not limitative, even when the gap becomes very small.

Missoffe, Alexia; Juillard, Jerome; Aubry, Denis

2008-03-01

79

Online monitoring of the distributed lateral displacement in large AC power generators using a high spatial resolution Brillouin optical fiber sensor  

NASA Astrophysics Data System (ADS)

We report for the first time, to the best of our knowledge, online monitoring of the distributed lateral displacement in large AC power generators using high spatial resolution differential pulse-width pair Brillouin optical time-domain analysis (DPP-BOTDA). To perform the measurement of distributed lateral displacements with periods of only a few cm in large AC power generators, a 2 cm spatial resolution strain measurement is realized using the differential pulse pair of 8/8.2 ns in DPP-BOTDA, and then the lateral displacements are reconstructed according to the strain-displacement relation with the assumption of a sine shape function. Using different fiberglass ripple springs, two types of lateral displacement with periods of 3 and 3.25 cm are demonstrated, obtaining a maximum displacement of 0.43 mm with a measurement accuracy of ~ 40 µm. This provides the information on the stator coil tightness through online monitoring of the distributed lateral displacement caused by the fiberglass ripple springs, and ensures safe operating conditions for large AC power generators. In addition, the large number of sensing points associated with distributed optical fiber sensors make it economically and technically practical to monitor large numbers of key components in a generator without any interference from the large magnetic and electrical fields.

Dong, Yongkang; Bao, Xiaoyi; Chen, Liang

2011-11-01

80

Large-scale separation of amino acids by continuous displacement chromatography  

SciTech Connect

Continuous annular chromatography (CAC) is a developing technology that allows truly continuous chromatographic separations. Previous work has demonstrated the utility of this technology for the separation of various materials by isocratic elution on a bench scale. Novel applications and improved operation of the process were studied in this work, demonstrating that CAC is a versatile apparatus which is capable of separations at high throughput. Three specific separation systems were investigated. Pilot-scale separations at high loadings were performed using an industrial sugar mixture as an example of scale-up for isocratic separations. Bench-scale experiments of a low concentration metal ion mixture were performed to demonstrate stepwise elution, a chromatographic technique which decreases dilution and increases sorbent capacity. Finally, the separation of mixtures of amino acids by ion exchange was investigated to demonstrate the use of displacement development on the CAC. This technique, which perhaps has the most potential, when applied to the CAC allowed simultaneous separation and concentration of multicomponent mixtures on a continuous basis. Mathematical models were developed to describe the CAC performance and optimize the operating conditions. For all the systems investigated, the continuous separation performance of the CAC was found to be very nearly the same as the batchwise performance of conventional chromatography. The technology appears, thus, to be very promising for industrial applications.

DeCarli, J.P. II; Carta, G.; Byers, C.H.

1989-10-01

81

Displacement Talbot lithography: a new method for high-resolution patterning of large areas.  

PubMed

Periodic micro and nano-structures can be lithographically produced using the Talbot effect. However, the limited depth-of-field of the self-images has effectively prevented its practical use, especially for high-resolution structures with periods less than 1 micrometer. In this article we show that by integrating the diffraction field transmitted by a grating mask over a distance of one Talbot period, one can obtain an effective image that is independent of the absolute distance from the mask. In this way high resolution periodic patterns can be printed without the depth-of-field limitation of Talbot self-images. For one-dimensional patterns the image obtained is shown to be related to the convolution of the mask transmission function with itself. This technique, which we call Displacement Talbot Lithography (DTL), enables high-resolution photolithography without the need for complex and expensive projection optics for the production of periodic structures like diffraction gratings or photonic crystals. Experimental results showing the printing of linear gratings and an array of holes on a hexagonal lattice are presented. PMID:21643324

Solak, Harun H; Dais, Christian; Clube, Francis

2011-05-23

82

The Cool Atomic Gas in the Large Magellanic Cloud  

NASA Astrophysics Data System (ADS)

We present the results of a third 21 cm absorption line survey toward the Large Magellanic Cloud (LMC) carried out with the Australia Telescope Compact Array. 20 compact continuum sources have been choosen from the 1.4 GHz snapshot continuum survey of Marx et al. (1997) to study the cool atomic gas near the supergiant shell LMC4, in the surroundings of 30 Doradus and in the direction of the eastern steep HI boundary. We have identified 20 absorption features toward 9 of the 20 sources. The properties of the cool HI clouds are investigated and are compared for the different regions of the LMC taking the results of Dickey et al. (1994, survey 2) into account. The cool HI gas in the LMC is either unusually abundant compared to the cool atomic phase of the Milky Way or the gas is clearly colder (Tc ~ 30 K) than that in our Galaxy (Tc ~ 60 K). The fraction of cool gas in the LMC compared to the warm gas is rather determined by local conditions of the interstellar medium (e.g. HII regions, SNRs) than by the distance from the gravitational centre. The properties of atomic clouds toward 30 Doradus and LMC4 suggest a higher cooling rate in these regions compared to other parts of the LMC, probably due to an enhanced pressure near the shock fronts of LMC4 and 30 Doradus. In contrast, the atomic gas is predominantly in the warm phase at the eastern steep HI boundary in spite of an expected compression zone.

Marx-Zimmer, M.; Zimmer, F.; Herbstmeier, U.; Dickey, J. M.; Staveley-Smith, L.

83

Syntectonic remagnetization in the southern Methow block: Resolving large displacements in the southern Canadian Cordillera  

USGS Publications Warehouse

The Upper Cretaceous Ventura Member of the Goat Wall unit in the southern Methow block of southern British Columbia and northern Washington State holds a syntectonic magnetization. Eight new sites from Manning Park in British Columbia give a mean direction of D = 27.5??, I = 60.1??, k = 304.7, ??95 = 3.2?? after optimal partial tilt correction. Of five groups of bedded sites from farther south in the basin reported by Bazard et al. [1990], four have a syntectonic remanence with a direction similar to what we observe. The exception is one group which has optimal concentration of remanence directions on >100% untilting and an abherent direction which must be rejected. Combining the accepted sites, the optimal differential syntilting direction is D = 11.8??, I = 61.5??, k = 39.3, ??95 = 3.4?? (N = 47), giving a mean pole of 79.8??N, 359.2??E, K = 19.5, and A95 = 4.8??. The age of the remagnetization is constrained to be between 88 and 80 Ma. Compared to cratonic North America, this result indicates that the southern Methow block was displaced from the south by 1800 ?? 500 km, meaning it lay south of the Sierra Nevada subduction zone but well north of other paleomagnetically constrained Cretaceous rock units from the Insular superterrane, including correlative strata of the Mount Tatlow area in the northern Methow block. Among several possibilities to reconcile this discrepancy, the most plausible has the whole Methow block translated coherently but with the southern Methow block strata remagnetized during transit.

Enkin, R. J.; Mahoney, J. B.; Baker, J.; Kiessling, M.; Haugerud, R. A.

2002-01-01

84

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

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

85

The variations in space of the displacement response spectrum at large periods using k-net data  

NASA Astrophysics Data System (ADS)

I use the large magnitude inland earthquakes of Japan, recorded by the accelerometric K-net network to study the spatial variations of the displacement response spectra (SD) at large frequencies. The scope is to observe directly the low frequency patterns of the seismic source radiation such as the focal mechanism and the directivity, since the asymptotic value of the displacement response spectra is the peak ground displacement (PGD). The advantage of using the SD as a proxy to the PGD, compared to a direct estimation on a double integration of the acceleration, is its stability and its simplicity. No signal processing is required to compute large period ordinates of the SD except a simple mean removal and a padding. I choose as reference a period of 10 sec. Its decay with the distance shows that it is linked mainly to the surface waves. Thus I present this type of data corrected by the square root of the distance (SD10R). I study different earthquakes with focal mechanisms either strike or dip slip. The first example is the 2000 Tottori Earthquake which is didactic since its mechanism is a strike slip and it is a well study case. When all the SD10R values are plotted on a map, they show directly the nodes of the focal mechanism as it was shown before by Takemura and al. (2009) with the S waves. The map of the SD10R deduced from the tangential components exhibits a radiation pattern characteristic of the Love's wave meanwhile a 45° rotation is observed on the SD10R map computed with the vertical component, corresponding to a Rayleigh's wave pattern. The plot of the SD10 parameter versus the azimuth shows also clearly the lobes of the focal mechanism. When the natural period of the oscillator is reduced toward 1 sec., the focal mechanism imprint vanishes around 3 sec., which is a much lower frequency that the one found by Takemura and al. (2009). However, the data are not the same as well as the measured parameter.ocal mechanism nodes observed with the SD10R computed from the tangential component of the soil acceleration.

Herrero, A.

2012-12-01

86

Large displacement FEM modelling of the cone penetration test (CPT) in normally consolidated sand  

NASA Astrophysics Data System (ADS)

A new finite element model based on a large strain formulation has been developed to study cone penetration in normally consolidated sand. An auto-adaptive remeshing technique was utilized for handling the very large distortion of sand surrounding the cone tip. A frictional contact interface utilizing Mohr-Coulomb's theory was chosen to represent interactions between the surface of the cone and sand. To model the sand behaviour, the non-associated Drucker-Prager constitutive model was selected. ABAQUS, a commercial finite element software package, was used to implement the model. The explicit solution algorithm was chosen due to its effectiveness for complicated contact problems. Analysis results proved that the model successfully captured the cone penetration behavior in sand. In addition, a chart to predict internal friction angles based on cone tip resistance for different vertical effective stresses was provided. This paper also shows a typical distribution of sleeve resistance, tip resistance - penetration relationship, and typical contours of vertical, horizontal, and shear stresses in normally consolidated sand. Finally, a non-uniform resistance was found along the length of the friction sleeve.

Susila, Endra; Hryciw, Roman D.

2003-06-01

87

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

88

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

Microsoft Academic Search

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

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

1986-01-01

89

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

NASA Astrophysics Data System (ADS)

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 Å, b=5.4549 Å, c=24.9195 Å. 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 ~0.15 Å. 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 ?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.

Vlasenko, Valery G.; Shuvaev, Anatoliy T.; Pirog, Irina V.; Drannikov, Dmitriy; Zarubin, Ivan A.

2007-02-01

90

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

NASA Astrophysics Data System (ADS)

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 coil diameter to wire diameter) SMA coils for use as actuators in morphing aerospace systems. Specifically, we describe the development and characterization of minimum achievable spring index coiled actuators made from 0.3048 mm (0.012") diameter shape memory alloy (SMA) wire for integration in textile architectures for future compression space suit applications. Production and shape setting of the coiled actuators, as well as experimental test methods, are described. Force, length and voltage relationships for multiple coil actuators are reported and discussed. The actuators exhibit a highly linear (R2 < 0.99) relationship between isometric blocking force and coil displacement, which is consistent with current SMA coil models; and SMA coil actuators demonstrate the ability to produce significant linear forces (i.e., greater than 8 N per coil) at strains up to 3x their initial (i.e., fully coiled) length. Discussions of both the potential use of these actuators in future compression space suit designs, and the broader viability of these actuators in both macro- and micro-systems, are presented.

Holschuh, Brad; Newman, Dava

2014-03-01

91

Development of a centrifugal atomization process for the production of large spherical metal powders  

Microsoft Academic Search

A centrifugal atomization process was developed for the production of large spherical metal powders. The final design of the process incorporated a low speed rotating liquid bath (RLB) for the cooling of atomized molten metal droplets generated from an atomizing disk. Experiments were conducted in an open air system with pure Ag and with an alloy of Ag-15 wt %

Funke

1991-01-01

92

Problem of large displacements of buried pipelines. Part 2. Stability of straight pipeline under ideally plastic of soil deformation  

Microsoft Academic Search

We developed analytical models of the buckling failure of initially rectilinear pipeline in the environment. We specify the\\u000a drawbacks of available analytical methods, which take no account of the possible longitudinal displacement of the pipeline\\u000a points or the limited length of the pipeline portion, as well as, in the limiting case, fail to describe the experimental\\u000a results of buckling failure

I. V. Orynyak; A. V. Bogdan

2007-01-01

93

Combination of large atomic power stations with desalination plants  

Microsoft Academic Search

Conclusions 1.The Soviet Union is one of a large number of countries interested in solving the problem of water supplies to regions with a lack of fresh water. Allowing for the scale of existing demands for water and their prospective growth, an important factor in solving the popular-economic problem is that of using nuclear power reactors of already-developed types, together

A. I. Churin; V. A. Klyachko; Yu. I. Koryakin; G. M. Solov'ev; A. A. Loginov; V. V. Rybachev

1968-01-01

94

Accommodation of Large Displacement along Thin Principal Slip Layer of a Fault: An Example of the Garam Thrust in the Paleozoic Taebaeksan Basin  

NASA Astrophysics Data System (ADS)

The principal slip layer (PSL) along which most of the shear displacement within a fault zone occurs is very narrow (less than 1-5 mm) and it is not so clear how this narrow layer accommodates a large (several m to several km) displacement. The NNW-striking and WSW-dipping Garam Thrust puts the Cambrian Wagok Formation on top of the Ordovician Mungok Formation in the Paleozoic Taebaeksan Basin of Korea. The Wagok Formation of the hanging wall is a massive dolostone consisting of euhedral dolomite grains (0.1-1 mm) and some fossil fragments. In contrast, the Mungok Formation of the footwall is a bedded limestone composed of calcite (20-150 ?m) with some fossil fragments and dolomite. The estimated minimum displacement of the thrust is about 120 m. The principal slip zone between the two formations is only 3-10 mm thick and filled by vein calcites (100-500 ?m in size) with foam texture. The hanging wall dolostone is highly fractured or “pulverized” while the footwall limestone is almost intact except a micro shear zone near the principal slip layer. In and adjacent to the principal slip layer, there are no fault rocks such as gouge or cataclasite. Prismatic euhedral quartz grains (100-200 ?m long) occurs within and around the principal slip layer suggesting infiltration of fluid rich in silica as well as carbonate along the principal slip layer. In view of the absence of fault rocks within and adjacent to the principal slip layer, the possible accommodation processes of the large displacement along the thin layer may include fault lubrication by nano-crystalline decomposition products of carbonate minerals and fluid effect. To test these possibilities, textural analyses on the principal slip zone and micro shear zone using scanning electron microscopy are under way and we will discuss these results.

Kim, S.; Ree, J.

2009-12-01

95

Ion-channeling observation of correlated atomic displacements below Tc in YBa sub 2 Cu sub 3 O sub 7-x and Pb-doped Bi sub 2 Sr sub 2 CaCu sub 2 O sub x  

SciTech Connect

Temperature dependent studies of ion channeling in high-quality, high-Tc single-crystals are summarized. The measurements revealed an abrupt change across Tc in displacements in the a-b plane of the Cu(I and 2) and 0(4) atoms; normal Debye-like'' vibrations were found for the Y and Ba atoms. The anomalous atomic displacements were found for both proton and He channeling, and manifested themselves as an abrupt increase in the critical angle and a simultaneous decrease in the minimum yield. The anomalous change in Cu-0 displacements shifted directly with stoichiometry-induced changes in Tc, implying a causal fink between the observed phonon anomaly and the superconducting state. An apparently identical anomaly was found in (Bi{sub 1.7}Pb{sub 0.3})Sr{sub 2}CaCu{sub 2}O{sub x}, indicating that it is a general feature of high-T, superconductivity. A comparison with other experimental measurements in YBa{sub 2}Cu{sub 3}O{sub 7-x}, including a detailed neutron diffraction study, indicates that the anomaly is not due to an overall reduction in average vibrational amplitude, but arises instead from a strongly correlated sequence of Cu(1 and 2) and 04 displacements that appears with the onset of superconductivity. These strongly correlated displacements are either dynamic, or they are static distortions that fail to preserve the overall crystal symmetry.

Rehn, L.E.; Sharma, R.P.; Baldo, P.M.

1992-07-01

96

Hydrogen transport diagnostics by atomic and molecular emission line profiles simultaneously measured for large helical device  

NASA Astrophysics Data System (ADS)

We observe the Balmer-?, -?, and -? lines of hydrogen atoms and Q branches of the Fulcher-? band of hydrogen molecules simultaneously with their polarization resolved for large helical device. From the fit including the line splits and the polarization dependences by the Zeeman effect, the emission locations, intensities, and the temperatures of the atoms and molecules are determined. The emission locations of the hydrogen atoms are determined outside but close to the last closed flux surface (LCFS). The results are consistent with a previous work (Phys. Plasmas 12, 042501 (2005)). On the other hand, the emission locations of the molecules are determined to be in the divertor legs, which is farer from those of the atoms. The kinetic energy of the atoms is 1 ~ 20 eV, while the rotational temperature of molecules is ~0.04 eV. Additionally, substantial wings, which originate from high velocity atoms and are not reproduced by the conventional spectral analysis, are observed in the Balmer line profiles. We develop a one-dimensional model to simulate the transport of the atoms and molecules. The model reproduces the differences of the emission locations of the atoms and molecules when their initial temperatures are assumed to be 3 eV and 0.04 eV, respectively. From the model, the wings of the Balmer-? line is attributed to the high velocity atoms exist deep inside the LCFS, which are generated by the charge exchange collisions with hot protons there.

Fujii, K.; Shikama, T.; Goto, M.; Morita, S.; Hasuo, M.

2013-01-01

97

Large two-atom two-photon vacuum Rabi oscillations in a high-quality cavity  

SciTech Connect

We predict a large cooperative effect involving two-atom two-photon vacuum Rabi oscillations in a high-quality cavity. The two-photon emission occurs as a result of simultaneous deexcitation of both atoms with two-photon resonance condition {omega}{sub 1}+{omega}{sub 2}{approx_equal}{omega}{sub a}+{omega}{sub b}, where {omega}{sub 1},{omega}{sub 2} are the atomic transition frequencies and {omega}{sub a},{omega}{sub b} are the frequencies of the emitted photons. The actual resonance condition depends on the vacuum Rabi couplings. The effect can be realized either with identical atoms in a bimodal cavity or with nonidentical atoms in a single-mode cavity.

Pathak, P.K.; Agarwal, G.S. [Physical Research Laboratory, Navrangpura, Ahmedabad 380 009 (India)

2004-10-01

98

Towards improving the quality of semiconducting diamond layers doped with large atoms  

Microsoft Academic Search

Previous studies on phosphorus- and aluminium-dopant activation in ion-implanted diamonds indicated that vacancies can either act to compensate the dopants or, when annealed at a temperature where they diffuse (600°C), they can interact to passivate these same dopant atoms. In order to improve the quality of diamond layers doped with large atoms, ways must be found to counteract such passivation.

Johan F. Prins

1999-01-01

99

Image-preprocessing method for near-wall particle image velocimetry (PIV) image interrogation with very large in-plane displacement  

NASA Astrophysics Data System (ADS)

Accurate particle image velocimetry (PIV) measurements very near the wall are still a great challenge. The problem is compounded by the very large in-plane displacement on PIV images commonly encountered in measurements in hypersonic boundary layers. An improved image-preprocessing method is presented in this paper which expands the traditional window deformation iterative multigrid scheme to PIV images with very large displacement. Before the interrogation, stationary artificial particles of uniform size are added homogeneously in the wall region. The mean squares of the intensities of signals in the flow and in the wall region are postulated to be equal when half the initial interrogation window overlaps the wall region. The initial estimation near the wall is then smoothed by data from both sides of the shear layer to reduce the large random uncertainties. Interrogations in the following iterative steps then converge to the correct results to provide accurate predictions for particle tracking velocimetries. Significant improvement is seen in Monte Carlo simulations and experimental tests. The algorithm successfully extracted the small flow structures of the second-mode wave in the hypersonic boundary layer from PIV images with low signal-noise-ratios when the traditional method was not successful.

Zhu, Yiding; Yuan, Huijing; Zhang, Chuanhong; Lee, Cunbiao

2013-12-01

100

Optically trapped atom interferometry using the clock transition of large 87Rb Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

We present a Ramsey-type atom interferometer operating with an optically trapped sample of 106 Bose-condensed 87Rb atoms. We investigate this interferometer experimentally and theoretically with an eye to the construction of future high precision atomic sensors. Our results indicate that, with further experimental refinements, it will be possible to produce and measure the output of a sub-shot-noise-limited, large atom number BEC-based interferometer. The optical trap allows us to couple the |F=1, mF=0rang?|F=2, mF=0rang clock states using a single photon 6.8 GHz microwave transition, while state selective readout is achieved with absorption imaging. We analyse the process of absorption imaging and show that it is possible to observe atom number variance directly, with a signal-to-noise ratio ten times better than the atomic projection noise limit on 106 condensate atoms. We discuss the technical and fundamental noise sources that limit our current system, and present theoretical and experimental results on interferometer contrast, de-phasing and miscibility.

Altin, P. A.; McDonald, G.; Döring, D.; Debs, J. E.; Barter, T. H.; Close, J. D.; Robins, N. P.; Haine, S. A.; Hanna, T. M.; Anderson, R. P.

2011-06-01

101

102({h_bar}/2{pi})k Large Area Atom Interferometers  

SciTech Connect

We demonstrate atom interferometers utilizing a novel beam splitter based on sequential multiphoton Bragg diffractions. With this sequential Bragg large momentum transfer (SB-LMT) beam splitter, we achieve high contrast atom interferometers with momentum splittings of up to 102 photon recoil momenta (102({h_bar}/2{pi})k). To our knowledge, this is the highest momentum splitting achieved in any atom interferometer, advancing the state-of-the-art by an order of magnitude. We also demonstrate strong noise correlation between two simultaneous SB-LMT interferometers, which alleviates the need for ultralow noise lasers and ultrastable inertial environments in some future applications. Our method is intrinsically scalable and can be used to dramatically increase the sensitivity of atom interferometers in a wide range of applications, including inertial sensing, measuring the fine structure constant, and detecting gravitational waves.

Chiow, Sheng-wey; Kovachy, Tim; Chien, Hui-Chun; Kasevich, Mark A. [Department of Physics, Stanford University, Stanford, California 94305 (United States)

2011-09-23

102

Nonextensive approach to the Thomas-Fermi model for an atom within a large magnetic field  

NASA Astrophysics Data System (ADS)

The nonextensive Thomas-Fermi model with thermal effects is extended to the case of atoms within a large magnetic field. A generalization of the Thomas-Fermi equation is derived. The virial theorem is verified and the dielectric screening process is revisited in the present extended model. Some comparisons are made with the case without a magnetic field or/and without nonextensivity.

Ourabah, Kamel; Tribeche, Mouloud

2013-09-01

103

Diffraction and vibrational dynamics of large clusters from He atom scattering  

Microsoft Academic Search

The vibrational dynamics of large Arn clusters from n=30 to n=4500 is investigated by measuring the energy loss of He atoms in a high resolution scattering experiment. The clusters are generated by adiabatic expansion through conical nozzles and contain a distribution of cluster sizes. The He supersonic nozzle beam provides a resolution of better than 1 meV. The results are

Udo Buck; Reinhard Krohne; Jörg Siebers

1993-01-01

104

The effect of large veins on spatial localization with GE BOLD at 3 T: Displacement, not blurring.  

PubMed

We used two different methods of region of interest (ROI) definition to investigate the spatial accuracy of functional magnetic resonance imaging (fMRI) at low and high spatial resolution. The "single-condition localizer" consisted of block alternation between a target stimulus and a mean gray background. The "differential localizer" consisted of block alternation between the target stimulus and another stimulus that filled the complement of the visual field. A separate series of scans, in which the target stimulus was presented briefly with long inter-stimulus intervals, was used to measure the hemodynamic impulse response function (HIRF). As expected, the differential localizer defined more restricted ROIs that better matched the predicted cortical representation of the target stimulus. However, at low resolution (3-mm isotropic) many voxels that responded positively to the target stimulus in the differential protocol responded negatively to the target stimulus in the single-condition localizer and in the HIRF measurements. The localization errors were attributed to voxels near large veins, which were identified based on low mean intensity and high variance. At high resolution (1.2-mm isotropic), the effects of large veins were present, but affected a smaller number of voxels. Thus, the use of differential localizers does not necessarily result in a more accurate indication of the underlying neural activity. Localization errors are reduced at higher spatial resolutions and can be eliminated by identification and removal of voxels dominated by large veins. PMID:17157534

Olman, Cheryl A; Inati, Souheil; Heeger, David J

2007-02-01

105

A practical method for the use of curvilinear coordinates in calculations of normal-mode-projected displacements and Duschinsky rotation matrices for large molecules  

NASA Astrophysics Data System (ADS)

While use of curvilinear coordinates such as bond lengths and bond angles is common in accurate spectroscopic and/or scattering calculations for triatomic and other small molecules, their use for large molecules is uncommon and restricted. For large molecules, normal-mode analysis is feasible but gives sensible results only if the dynamical or spectroscopic process being considered involves changes in angular coordinates, including ring deformations, which are so small that the motion can be approximated by its tangential component. We describe an approximate method by which curvilinear normal-mode-projected displacements and hence Franck-Condon factors, reorganization energies, and vibronic coupling constants, as well as Duschinsky (Dushinsky, Duschinskii) rotation matrices, can be evaluated for large systems. Three illustrative examples are provided: (i) to understand the nature of the first excited state of water, illustrating properties of large-amplitude bending motions; (ii) to understand the nature of the ``boat'' relaxation of the first excited state of pyridine, illustrating properties of large-amplitude torsional motions; and (iii) to understand the coupling of vibrational modes to the oxidation of bacteriochlorophyll-a, a paradigm with many applications to both chemical and biological electron transfer, illustrating properties of macrocyclic deformations. The method is interfaced to a wide variety of computational chemistry computer programs.

Reimers, Jeffrey R.

2001-11-01

106

Large-scale chromatin de-compaction induced by low light is not accompanied by nucleosomal displacement  

PubMed Central

Arabidopsis thaliana is widely used as a model to study chromatin compaction dynamics during development and in response to the environment. Signals such as prolonged heat treatment, low light and pathogen infestation are known to induce large-scale de-condensation of nuclear chromatin. Here we demonstrate that the response to different environments varies at the nucleosomal level. Our results show that in contrast to previous reports on heat and biotic infestation, low light intensity signaling does not alter nucleosomal occupancy, despite the marked effects of low light on global chromatin compaction.

Peeters, Anton JM; Fransz, Paul

2010-01-01

107

Displaced Supersymmetry  

NASA Astrophysics Data System (ADS)

The apparent absence of light superpartners at the LHC strongly constrains the viability of the MSSM as a solution to the hierarchy problem. These constraints can be significantly alleviated by R-parity violation (RPV). Bilinear R-parity violation, with the single operator LH u , does not require any special flavor structure and can be naturally embedded in a GUT while avoiding constraints from proton decay (unlike baryon-number-violating RPV). The LSP in this scenario can be naturally long-lived, giving rise to displaced vertices. Many collider searches, particularly those selecting b-jets or leptons, are insensitive to events with such detector-scale displaced decays owing to cuts on track quality and impact parameter. We demonstrate that for decay lengths in the window ˜1-103 mm, constraints on superpartner masses can be as low as ˜450 GeV for squarks and ˜40 GeV for LSPs. In some parts of parameter space light LSPs can dominate the Higgs decay width, hiding the Higgs from existing searches. This framework motivates collider searches for detector-scale displaced vertices. LHCb may be ideally suited to trigger on such events, while ATLAS and CMS may need to trigger on missing energy or multijet signatures.

Graham, Peter W.; Kaplan, David E.; Rajendran, Surjeet; Saraswat, Prashant

2012-07-01

108

A study of the relationship between interplanetary parameters and large displacements of the nightside polar cap boundary  

SciTech Connect

On July 14, 1982 the Sweden and Britain Radar-Aurora Experiment (SABRE) observed the ionospheric flow reversal boundary at {approximately} 0400 MLT to move equatorward across the radar field of view and then later to return poleward. The polar cap appeared to be considerably inflated at this time. Concurrent observations by ISEE-3 at the L1 libration point of the solar wind speed and density, and of the interplanetary magnetic field (IMF) indicated that the solar wind conditions were unusual throughout the interval under consideration. A mapping of the solar wind parameters from the L1 point to the subsolar magnetopause and thence to the SABRE local time sector indicates that the equatorward motion of the polar cap boundary was controlled by a southward turning of the IMF. The inference of a concomitant increase in open magnetic flux is supported by a comparison of the magnetopause location observed by ISEE-1 on an inbound pass in the 2,100 MLT sector with a magnetopause model based upon the solar wind measurements made by ISEE-3. Some 20 minutes after the expansion of the polar cap boundary was first seen by SABRE, there was a rapid contraction of the boundary, the casue of which was independent of the INF and solar wind parameters, and which had a poleward velocity component in excess of 1,900 m s{sup {minus}1}. the boundary as it moved across the radar field of view was highly structured and oriented at a large angle to the ionospheric footprints of the magnetic L shells. Observations in the premidnight sector by the Air Force Geophysics Laboratory (AFGL) magnetometer array indicate that the polar cap contraction is caused by substorm draining of the polar cap flux and occurs without a clearly associated trigger in the interplanetary medium. The response time in the early morning local time sector to the substorm onset switch is approximately 20 minutes, equivalent to an ionospheric azimuthal phase velocity of some 5 km s{sup {minus}1}.

Lester, M. (Univ. of Leicester (England)); Freeman, M.P.; Southwood, D.J. (Imperial College, London (England)); Waldock, J.A. (Sheffield City Polytechnic (England)); Singer, H.J. (Air Force Geophysics Lab., Bedford, MA (USA))

1990-12-01

109

Towards benchmark second-order correlation energies for large atoms: Zn2+ revisited  

NASA Astrophysics Data System (ADS)

To provide very accurate reference results for the second-order Møller-Plesset (MP2) energy and its various components for Zn2+, which plays for 3d-electron systems a similar role as Ne for smaller atoms and molecules, we have performed extensive calculation by two completely different implementations of the MP2 method: the finite element method (FEM) and the variation-perturbation (VP) method. The FEM and VP calculations yield partial wave contributions up to lmax=45 and 12, respectively. Detailed comparison of all FEM and VP energy components for lmax=12 has disclosed an extraordinary similarity, which justifies using the present results as benchmarks. The present correlation energies are compared with other works. The dependability of an earlier version of FEM, already applied to very large closed-shell atoms, is confirmed. It has been found that for larger atoms the accuracy of the analytical Hartree-Fock results has an impact on the accuracy of the MP2 energies greater than for smaller atoms. Fields of applications of the present results in studies of various electron correlation effects in 3d-electron atoms and molecules are indicated.

Flores, J. R.; S?upski, R.; Jankowski, K.; Malinowski, P.

2004-12-01

110

Method for large-scale fabrication of atomic-scale structures on material surfaces using surface vacancies  

DOEpatents

A method for forming atomic-scale structures on a surface of a substrate on a large-scale includes creating a predetermined amount of surface vacancies on the surface of the substrate by removing an amount of atoms on the surface of the material corresponding to the predetermined amount of the surface vacancies. Once the surface vacancies have been created, atoms of a desired structure material are deposited on the surface of the substrate to enable the surface vacancies and the atoms of the structure material to interact. The interaction causes the atoms of the structure material to form the atomic-scale structures.

Lim, Chong Wee (Urbana, IL); Ohmori, Kenji (Urbana, IL); Petrov, Ivan Georgiev (Champaign, IL); Greene, Joseph E. (Champaign, IL)

2004-07-13

111

Collective Excitations of a Trapped Bose–Einstein Condensate at Finite Large Atom Numbers  

Microsoft Academic Search

We study the collective excitations of a trapped Bose–Einstein condensate for a large but finite number of atoms. Since our calculations go beyond the Thomas–Fermi approximation, the “quantum pressure” and the change of chemical potential due to the density fluctuations must be considered. The small kinetic energy enhancement and chemical potential reduction can't be neglected with respect to the strong

Yongli Ma; S. T. Chui; J. C. Kimball

2002-01-01

112

Force-feedback high-speed atomic force microscope for studying large biological systems.  

PubMed

We designed and developed a high-speed atomic force microscope (HSAFM) utilizing a force-feedback scheme for imaging large biological samples. The system collects three simultaneous images: a deflection image, a topographic image, and a force image. We demonstrated that this force-feedback HSAFM is capable of acquiring large topographic images of Escherichia coli biofilms at approximately one frame per second in air. We discuss how the self-actuating cantilever and the piezo tube follow those larger biological topographic features during the HSAFM imaging process. PMID:22555172

Kim, Byung I; Boehm, Ryan D

2012-12-01

113

Atoms and quantum dots with a large number of electrons: The ground-state energy  

SciTech Connect

We compute the ground-state energy of atoms and quantum dots with a large number N of electrons. Both systems are described by a nonrelativistic Hamiltonian of electrons in a d-dimensional space. The electrons interact via the Coulomb potential. In the case of atoms (d=3), the electrons are attracted by the nucleus via the Coulomb potential. In the case of quantum dots (d=2), the electrons are confined by an external potential, whose shape can be varied. We show that the dominant terms of the ground-state energy are those given by a semiclassical Hartree-exchange energy, whose N{yields}{infinity} limit corresponds to Thomas-Fermi theory. This semiclassical Hartree-exchange theory creates oscillations in the ground-state energy as a function of N. These oscillations reflect the dynamics of a classical particle moving in the presence of the Thomas-Fermi potential. The dynamics is regular for atoms and some dots, but in general in the case of dots, the motion contains a chaotic component. We compute the correlation effects. They appear at the order NlnN for atoms, in agreement with available data. For dots, they appear at the order N.

Kunz, Herve; Rueedi, Rico [Institute of Theoretical Physics, Ecole Polytechnique Federale de Lausanne (EPFL), CH-1015 Lausanne (Switzerland)

2010-03-15

114

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

PubMed

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

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

2014-03-14

115

Large-Area Atomic Oxygen Facility Used to Clean Fire-Damaged Artwork  

NASA Technical Reports Server (NTRS)

In addition to completely destroying artwork, fires in museums and public buildings can soil a displayed artwork with so much accumulated soot that it can no longer be used for study or be enjoyed by the public. In situations where the surface has not undergone extensive charring or melting, restoration can be attempted. However, soot deposits can be very difficult to remove from some types of painted surfaces, particularly when the paint is fragile or flaking or when the top surface of the paint binder has been damaged. Restoration typically involves the use of organic solvents to clean the surface, but these solvents may cause the paint layers to swell or leach out. Also, immersion of the surface or swabbing during solvent cleaning may move or remove pigment through mechanical contact, especially if the fire damage extends into the paint binder. A noncontact technique of removing organic deposits from surfaces was developed out of NASA research on the effects of oxygen atoms on various materials. Atomic oxygen is present in the atmosphere surrounding the Earth at the altitudes where satellites typically orbit. It can react chemically with surface coatings or deposits that contain carbon. In the reaction, the carbon is converted to carbon monoxide and some carbon dioxide. Water vapor is also a byproduct of the reaction if the surface contains carbon-hydrogen bonds. To study this reaction, NASA developed Earth-based facilities to produce atomic oxygen for material exposure and testing. A vacuum facility designed and built by the Electro-Physics Branch of the NASA Glenn Research Center at Lewis Field to provide atomic oxygen over a large area for studying reactions in low Earth orbit has been used to successfully clean several full-size paintings. (This facility can accommodate paintings up to 1.5 by 2.1 m. The atomic oxygen plasma is produced between two large parallel aluminum plates using a radiofrequency power source operating at roughly 400 W. Atomic oxygen is generated uniformly over this area at an operating pressure of 1 to 5 mtorr.

Rutledge, Sharon K.; Banks, Bruce A.; Steuber, Thomas J.; Sechkar, Edward A.

2000-01-01

116

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

SciTech Connect

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.

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

117

The Enigmatic 2008 Mw 6.9 Iwate-Miyagi Nairiku, Japan, Earthquake: A Large Shallow Thrust Event with Little Surface Displacement and Scant Evidence for Paleoseismic Slip  

NASA Astrophysics Data System (ADS)

The 14 June 2008 Mw 6.9 Iwate-Miyagi Nairiku earthquake struck the mountainous region in northern Honshu and was accompanied by isolated surface ruptures along ~20 km-long NNE-trend. To understand its relation to the seismogenic faulting at depth, we conducted field investigations immediately after the mainshock, performing detailed mapping and measuring fault displacements using a total station instrument and ground-based LiDAR. More than 12 fault-rupture sites suggest that the total length of the tectonic ground breakage reaches ~20 km. Contractional features such as thrust fault exposures, flexure, tilting, and buckling deformations predominate on the rupture zone, which is consistent with reverse faulting driven by the WNW-ESE compressional stress field in northern Honshu. Shortening as well as vertical displacements were visible on cultural features such as concrete, asphalt paved roads, sidewalks, guardrails, drainage ditches, and rice paddies. Soaked soil underlying paddy fields immediately after rice transplanting worked particularly well to measure such small deformations, separating them into emerged and submerged parts. Amounts of vertical offset and horizontal shortening measured using such cultural piercing points are mostly less than 50 cm, indicating ~1m of net fault slip. Near the southern end of the rupture zone, the fault structure and slip sense become complex and measured offsets are exceptionally large. We found a ~1-km-long E-W-striking continuous rupture with up to 7 m right-lateral and 4 m vertical offsets of a paved road, trails, and rills near the northern rim of the Aratozawa dam reservoir. LiDAR measurements together with our field observations reveal features typical of strike-slip faulting such as mole tracks, fissures, pressure ridges, bulges, tilted trees, and shutter ridges, as well as the offset rills and ridges. The mapped zone of ruptures approximately locates along the central part of the surface projection of an inferred ~40-km-long west- dipping source fault and associated 2-12 km-deep aftershock zone. It also corresponds to a patch of high slip estimated from seismic and geodetic inversions. However, from the viewpoint of the long-term predictability of damaging earthquakes from surface faults, the surface fracturing occurred where no active fault was previously mapped. Although there is geomorphic evidence that strands of this fault had ruptured prehistorically, it would not have allowed us to properly evaluate entire extent of the rupture and therefore the size of the shock.

Toda, S.; Maruyama, T.; Yoshimi, M.; Awata, Y.; Kaneda, H.; Yoshioka, T.; Ando, R.

2008-12-01

118

Large-Scale Atomistic Simulations of Solid State Materials -- Modeling Many Millions of Atoms on Parallel Computers  

Microsoft Academic Search

Structural and dynamical correlations including crack propagation and fracture in nanophase materials, atomic level stresses in nanopixels, nanoindentation in crystalline and amorphous materials, and dynamics of oxidation in metallic nanoparticles will be discussed using large-scale atomistic simulations. Multiresolution molecular-dynamics (MRMD) approach for multimillion atom simulations has been used to carry out the 10-100 million atom simulations on a variety of

Priya Vashishta

2000-01-01

119

Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) Simulations of the Molecular Crystal alphaRDX.  

National Technical Information Service (NTIS)

This reference manual provides instructions for determining atomistic material properties important for modeling dislocations in the energetic molecular crystal RDX using the Large-Scale Atomic/Molecular Massively Parallel Simulator (LAMMPS) molecular dyn...

L. B. Munday P. W. Chung

2013-01-01

120

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

SciTech Connect

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.

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

121

A large-scale cold atom source in an integrating sphere  

NASA Astrophysics Data System (ADS)

An integrating sphere with a diameter of 10 cm is developed for cooling atoms. The maximum number of 2 × 1010 cold atoms is obtained from a background vapor with 220 mW cooling laser power. The cold atom number can be increased by further increasing the cooling power. Such cold atom source would have potential use for Raman-Ramsey atomic clock with good signal-to-noise ratio (SNR).

Zheng, Ben-Chang; Cheng, Hua-Dong; Meng, Yan-Ling; Liu, Peng; Wang, Xiu-Mei; Xiao, Ling; Wan, Jin-Yin; Liu, Liang

2014-05-01

122

A thermal modelling of displacement cascades in uranium dioxide  

NASA Astrophysics Data System (ADS)

The space and time dependent temperature distribution was studied in uranium dioxide during displacement cascades simulated by classical molecular dynamics (MD). The energy for each simulated radiation event ranged between 0.2 keV and 20 keV in cells at initial temperatures of 700 K or 1400 K. Spheres into which atomic velocities were rescaled (thermal spikes) have also been simulated by MD to simulate the thermal excitation induced by displacement cascades. Equipartition of energy was shown to occur in displacement cascades, half of the kinetic energy of the primary knock-on atom being converted after a few tenths of picoseconds into potential energy. The kinetic and potential parts of the system energy are however subjected to little variations during dedicated thermal spike simulations. This is probably due to the velocity rescaling process, which impacts a large number of atoms in this case and would drive the system away from a dynamical equilibrium. This result makes questionable MD simulations of thermal spikes carried out up to now (early 2014). The thermal history of cascades was compared to the heat equation solution of a punctual thermal excitation in UO2. The maximum volume brought to a temperature above the melting temperature during the simulated cascade events is well reproduced by this simple model. This volume eventually constitutes a relevant estimate of the volume affected by a displacement cascade in UO2. This definition of the cascade volume could also make sense in other materials, like iron.

Martin, G.; Garcia, P.; Sabathier, C.; Devynck, F.; Krack, M.; Maillard, S.

2014-05-01

123

An atomic-absorption method for the determination of gold in large samples of geologic materials  

USGS Publications Warehouse

A laboratory method for the determination of gold in large (100-gram) samples has been developed for use in the study of the gold content of placer deposits and of trace amounts of gold in other geologic materials. In this method the sample is digested with bromine and ethyl ether, the gold is extracted into methyl isobutyl ketone, and the determination is made by atomicabsorption spectrophotometry. The lower limit of detection is 0.005 part per million in the sample. The few data obtained so far by this method agree favorably with those obtained by assay and by other atomic-absorption methods. About 25 determinations can be made per man-day.

VanSickle, Gordon H.; Lakin, Hubert William.

1968-01-01

124

Atomic structure of a single large biomolecule from diffraction patterns of random orientations.  

PubMed

The short and intense pulses of the new X-ray free electron lasers, now operational or under construction, may make possible diffraction experiments on single molecule-sized objects with high resolution, before radiation damage destroys the sample. In a single molecule imaging (SMI) experiment thousands of diffraction patterns of single molecules with random orientations are recorded. One of the most challenging problems of SMI is how to assemble these noisy patterns of unknown orientations into a consistent single set of diffraction data. Here we present a new method which can solve the orientation problem of SMI efficiently even for large biological molecules and in the presence of noise. We show on simulated diffraction patterns of a large protein molecule, how the orientations of the patterns can be found and the structure to atomic resolution can be solved. The concept of our algorithm could be also applied to experiments where images of an object are recorded in unknown orientations and/or positions like in cryoEM or tomography. PMID:22575364

Tegze, Miklós; Bortel, Gábor

2012-07-01

125

Large-scale pseudostate calculations for electron scattering from neon atoms  

NASA Astrophysics Data System (ADS)

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)].

Zatsarinny, Oleg; Bartschat, Klaus

2012-06-01

126

High-resolution and large dynamic range nanomechanical mapping in tapping-mode atomic force microscopy.  

PubMed

High spatial resolution imaging of material properties is an important task for the continued development of nanomaterials and studies of biological systems. Time-varying interaction forces between the vibrating tip and the sample in a tapping-mode atomic force microscope contain detailed information about the elastic, adhesive, and dissipative response of the sample. We report real-time measurement and analysis of the time-varying tip-sample interaction forces with recently introduced torsional harmonic cantilevers. With these measurements, high-resolution maps of elastic modulus, adhesion force, energy dissipation, and topography are generated simultaneously in a single scan. With peak tapping forces as low as 0.6 nN, we demonstrate measurements on blended polymers and self-assembled molecular architectures with feature sizes at 1, 10, and 500 nm. We also observed an elastic modulus measurement range of four orders of magnitude (1 MPa to 10 GPa) for a single cantilever under identical feedback conditions, which can be particularly useful for analyzing heterogeneous samples with largely different material components. PMID:21832758

Sahin, Ozgur; Erina, Natalia

2008-11-01

127

BLOCK DISPLACEMENT METHOD FIELD DEMONSTRATION AND SPECIFICATIONS  

EPA Science Inventory

The Block Displacement technique has been developed as a remedial action method for isolating large tracks of ground contaminated by hazardous waste. The technique places a low permeability barrier around and under a large block of contaminated earth. The Block Displacement proce...

128

Single Cs atoms as collisional probes in a large Rb magneto-optical trap  

SciTech Connect

We study cold interspecies collisions of cesium and rubidium in a strongly imbalanced system with single and few Cs atoms. Observation of the single-atom fluorescence 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.

Weber, Claudia; John, Shincy; Spethmann, Nicolas; Meschede, Dieter; Widera, Artur [Institut fuer Angewandte Physik, Universitaet Bonn, Wegelerstr. 8, D-53115 Bonn (Germany)

2010-10-15

129

Single Cs atoms as collisional probes in a large Rb magneto-optical trap  

NASA Astrophysics Data System (ADS)

We study cold interspecies collisions of cesium and rubidium in a strongly imbalanced system with single and few Cs atoms. Observation of the single-atom fluorescence 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.

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

2010-10-01

130

Large quality factor in sheet metamaterials made from dark dielectric meta-atoms.  

PubMed

Metamaterials--or artificial electromagnetic materials--can create media with properties unattainable in nature, but mitigating dissipation is a key challenge for their further development. Here, we demonstrate a low-loss metamaterial by exploiting dark bound states in dielectric inclusions coupled to the external waves by small nonresonant metallic antennas. We experimentally demonstrate a dispersion-engineered metamaterial based on a meta-atom made from alumina, and we show that its resonance has a much larger quality factor than metal-based meta-atoms. Finally, we show that our dielectric meta-atom can be used to create sheet metamaterials with negative permittivity or permeability. PMID:24702415

Jain, Aditya; Tassin, Philippe; Koschny, Thomas; Soukoulis, Costas M

2014-03-21

131

Model for atomic layer deposition on inner wall of rectangular pipes with large aspect ratio  

NASA Astrophysics Data System (ADS)

Feasibility of thin films deposited on inner wall of rectangular pipes with length aspect ratio up to 50 by atomic layer deposition was studied, by solving kinetics equation of gas adsorption on inner wall of pipes. And the time for reactants to reach saturated adsorption in pipes was calculated. Furthermore, the process of thin film deposition by atomic layer deposition was simulated by Kinetic Monte Carlo method, and a growth model for atomic layer deposition of aluminum on inner wall of long rectangular pipes was established.

Xiong, Yuqing; Dong, Maojin; Li, Kun; Wang, Jizhou; Ren, Ni

2013-12-01

132

Crystal structure and thermoelectric properties of clathrate, Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}: Small cage volume and large disorder of the guest atom  

SciTech Connect

Samples with the type-I clathrate composition Ba{sub 8}Ni{sub x}Si{sub 46-x} have been synthesized and their structure and thermoelectric properties characterized. Microprobe analysis indicates the Ni incorporation to be 2.62{<=}x{<=}3.53. The x=3.5 phase crystallizes in the type-I clathrate structure (space group: Pm-3n) with a lattice parameter of 10.2813(3) A. The refined composition was Ba{sub 8}Ni{sub 3.5}Si{sub 42.0}, with small vacancies, 0.4 and 0.5 atoms per formula unit, at the 2a and 6c sites, respectively. The position of the Ba2 atom in the large cage was modeled using a 4-fold split position (24j site), displaced 0.18 A from the cage center (6d site). The volume of the large cage is calculated to be 146 A{sup 3}, smaller than other clathrates with similar cation displacement. The sample shows n-type behavior with a maximum of -50 {mu}V/K at 823 K above which the Seebeck coefficient decreases, suggesting mixed carriers. Lattice thermal conductivity, {kappa}{sub l}, is 55 mW/K above 600 K. - Graphical abstract: Seebeck coefficient and resistivity of the type-I clathrate Ba{sub 8}Ni{sub 3.5}Si{sub 41.0}. Structure show's large displacement of the Ba cation in the large cage (6c site). Highlights: Black-Right-Pointing-Pointer Crystal structure of the Ba{sub 8}Ni{sub 3.5}Si{sub 41.0} reported. Black-Right-Pointing-Pointer Vacancies at the 2a and 6c sites. Black-Right-Pointing-Pointer Large disorder of Ba guest atom, 0.18 A from cage center. Black-Right-Pointing-Pointer Structure is compared to Ba{sub 8}Si{sub 46} and other type-I clathrates. Black-Right-Pointing-Pointer Max Seebeck of -50.7 {mu}V/C at 798.4 K, thermal conductivity {approx}55 mW/K.

Roudebush, John H., E-mail: jhr@princeton.edu [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States); Orellana, Mike [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States); Bux, Sabah [Thermal Energy Conversion Technologies Group, Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA 91109 (United States); Yi Tanghong; Kauzlarich, Susan M. [Department of Chemistry, University of California, One Shields Ave., Davis, CA 95616 (United States)

2012-08-15

133

Ion-channeling observation of correlated atomic displacements below {Tc} in YBa{sub 2}Cu{sub 3}O{sub 7-x} and Pb-doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub x}  

SciTech Connect

Temperature dependent studies of ion channeling in high-quality, high-Tc single-crystals are summarized. The measurements revealed an abrupt change across Tc in displacements in the a-b plane of the Cu(I and 2) and 0(4) atoms; normal ``Debye-like`` vibrations were found for the Y and Ba atoms. The anomalous atomic displacements were found for both proton and He channeling, and manifested themselves as an abrupt increase in the critical angle and a simultaneous decrease in the minimum yield. The anomalous change in Cu-0 displacements shifted directly with stoichiometry-induced changes in Tc, implying a causal fink between the observed phonon anomaly and the superconducting state. An apparently identical anomaly was found in (Bi{sub 1.7}Pb{sub 0.3})Sr{sub 2}CaCu{sub 2}O{sub x}, indicating that it is a general feature of high-T, superconductivity. A comparison with other experimental measurements in YBa{sub 2}Cu{sub 3}O{sub 7-x}, including a detailed neutron diffraction study, indicates that the anomaly is not due to an overall reduction in average vibrational amplitude, but arises instead from a strongly correlated sequence of Cu(1 and 2) and 04 displacements that appears with the onset of superconductivity. These strongly correlated displacements are either dynamic, or they are static distortions that fail to preserve the overall crystal symmetry.

Rehn, L.E.; Sharma, R.P.; Baldo, P.M.

1992-07-01

134

Method for preparing ultraflat, atomically perfect areas on large regions of a crystal surface by heteroepitaxy deposition  

DOEpatents

A novel method of forming large atomically flat areas is described in which a crystalline substrate having a stepped surface is exposed to a vapor of another material to deposit a material onto the substrate, which material under appropriate conditions self arranges to form 3D islands across the substrate surface. These islands are atomically flat at their top surface, and conform to the stepped surface of the substrate below at the island-substrate interface. Thereafter, the deposited materials are etched away, in the etch process the atomically flat surface areas of the islands transferred to the underlying substrate. Thereafter the substrate may be cleaned and annealed to remove any remaining unwanted contaminants, and eliminate any residual defects that may have remained in the substrate surface as a result of pre-existing imperfections of the substrate.

El Gabaly, Farid; Schmid, Andreas K.

2013-03-19

135

Use of helium nanodroplets for assembly, transport, and surface deposition of large molecular and atomic clusters  

NASA Astrophysics Data System (ADS)

The utility of continuous beam of helium droplets for assembly, transport, and surface deposition of metal and molecular clusters is studied. Clusters of propyne having from about 10 to 104 molecules were obtained via sequential pickup of molecules by He droplets with average sizes in the range of 104-107 atoms. The maximum attainable flux of the propyne molecules carried by He droplets was found to be in the range of (5-15)×1015 molecules sr-1 s-1, being larger in larger droplets. The size of the clusters and the flux of the transported species are ultimately limited by the evaporative extinction of the entire helium droplet upon capture of particles. It is shown that the attenuation of the He droplet beam in the process of the cluster growth can be used in order to obtain the average size and the binding energy of the clusters. Furthermore, we used He droplets for assembling and surface deposition of gold and silver clusters having about 500 atoms. Typical deposition rate of metal atoms of about 3×1015 atoms sr-1 s-1 is comparable to or larger than obtained with other beam deposition techniques. We propose that doping of He droplets by Au and Ag atoms in two separate pickup chambers leads to formation of the bimetal clusters having core-shell structure.

Mozhayskiy, Vadim; Slipchenko, Mikhail N.; Adamchuk, Vera K.; Vilesov, Andrey F.

2007-09-01

136

Optically trapped atom interferometry using the clock transition of large 87Rb Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

In our original paper (Altin et al 2011 New J. Phys. 13 065020), we presented the results from a Ramsey atom interferometer operating with an optically trapped sample of up to 106 Bose-condensed 87Rb atoms in the mF = 0 clock states. We were unable to observe projection noise fluctuations on the interferometer output, which we attribute to the stability of our microwave oscillator and background magnetic field. Numerical simulations of the Gross-Pitaevskii equations for our system show that dephasing due to spatial dynamics driven by interparticle interactions accounts for much of the observed decay in fringe visibility at long interrogation times. The simulations show good agreement with the experimental data when additional technical decoherence is accounted for, and suggest that the clock states are indeed immiscible. With smaller samples of 5 × 104 atoms, we observe a coherence time of ? = 1.0+0.5-0.3 s.

Altin, P. A.; McDonald, G.; Döring, D.; Debs, J. E.; Barter, T. H.; Robins, N. P.; Close, J. D.; Haine, S. A.; Hanna, T. M.; Anderson, R. P.

2011-11-01

137

Large-Scale Atomistic Simulations of Solid State Materials -- Modeling Many Millions of Atoms on Parallel Computers  

NASA Astrophysics Data System (ADS)

Structural and dynamical correlations including crack propagation and fracture in nanophase materials, atomic level stresses in nanopixels, nanoindentation in crystalline and amorphous materials, and dynamics of oxidation in metallic nanoparticles will be discussed using large-scale atomistic simulations. Multiresolution molecular-dynamics (MRMD) approach for multimillion atom simulations has been used to carry out the 10-100 million atom simulations on a variety of parallel computer architectures including Cray T3E, SGI Origin, IBM SP, and large workstation clusters. Issues related to matching of length scales to carry out seamless simulations of electronic, atomic and continuum degrees of freedom will also be briefly discussed. Research presented in this talk is carried out in collaboration with Martina E. Bachlechner, Timothy Campbell, Ingvar Ebbsjo, Rajiv K. Kalia, Hideaki Kikuchi, Sanjay Kodiyalam, Elefterios Lidorikis, Anupam Madhukar, Aiichiro Nakano, Shuji Ogata, Subhash Saini, Fuyuki Shimojo, and Phillip Walsh. Research supported by the US DOE, NSF, AFOSR, ARO, USC-LSU MURI (DARPA & AFOSR), NASA, and LEQSF

Vashishta, Priya

2000-03-01

138

Particle displacement tracking for PIV  

NASA Technical Reports Server (NTRS)

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.

Wernet, Mark P.

1990-01-01

139

Displacement-dispersive liquid-liquid microextraction based on solidification of floating organic drop of trace amounts of palladium in water and road dust samples prior to graphite furnace atomic absorption spectrometry determination.  

PubMed

A new displacement-dispersive liquid-liquid microextraction method based on the solidification of floating organic drop was developed for separation and preconcentration of Pd(ll) in road dust and aqueous samples. This method involves two steps of dispersive liquid-liquid microextraction based on solidification. In Step 1, Cu ions react with diethyldithiocarbamate (DDTC) to form Cu-DDTC complex, which is extracted by dispersive liquid-liquid microextraction based on a solidification procedure using 1-undecanol (extraction solvent) and ethanol (dispersive solvent). In Step 2, the extracted complex is first dispersed using ethanol in a sample solution containing Pd ions, then a dispersive liquid-liquid microextraction based on a solidification procedure is performed creating an organic drop. In this step, Pd(ll) replaces Cu(ll) from the pre-extracted Cu-DDTC complex and goes into the extraction solvent phase. Finally, the Pd(ll)-containing drop is introduced into a graphite furnace using a microsyringe, and Pd(ll) is determined using atomic absorption spectrometry. Several factors that influence the extraction efficiency of Pd and its subsequent determination, such as extraction and dispersive solvent type and volume, pH of sample solution, centrifugation time, and concentration of DDTC, are optimized. PMID:24000764

Ghanbarian, Maryam; Afzali, Daryoush; Mostafavi, Ali; Fathirad, Fariba

2013-01-01

140

Structural inheritance vs large scale geodynamics, what controls the vertical displacement in the alboran-Rif sytem? Insights from 3D thermo-mechanical modeling  

NASA Astrophysics Data System (ADS)

The Alboran basin is a typical basin of the Mediterranean area in the sense that rapid extension followed a phase of thickening of the crust and is itself followed by a new shortening phase. In between these multiple phases of thickening and thinning of the crust, the thermal structure doesn't have the time to relax and participate as much as the faults and the reworked nappe stacked of different lithologies to the structural inheritage. The Alboran basin is however special because it presents the very deep (10km) basins as well as a very complex structure of the basements that features a multitude of accidents at short wavelength. We will present first the modeling assumption and the results of a preliminary parametric approach assessing in particular the evolution of subsidence rates and main faults activity with time as a function of two parameters: the strength of the lower crust and the timing of the last inversion. Comparing the results of the 3D models with the current structure of the basement, we conclude that structural inheritance can explain the structure of the eastern alboran basin and the location and geometry of the main active faults. However, the morphology of the western basin, as well as the rapid uplift that causes the Messinian Event are not captured with crustal/lithospheric scale models. We therefore use a second generation of upper mantle scale thermomechanical models to test different hypothesis concerning the formation of the western Alboran Basin and find that a 2 step removal of the mantle lithosphere from beneath the Alboran explains the structural data as well as the vertical displacement in the region.

Le Pourhiet, L.; May, D.; Smit, J.; Do Couto, D.; Gorini, C.

2011-12-01

141

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

NASA Astrophysics Data System (ADS)

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

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

2006-12-01

142

Electron Density Modeling of Large Systems Using the Transferable Atom Equivalent Method  

Microsoft Academic Search

The transferable atom equivalent (TAB) modeling method is a resource-efficient alternative to routine HF\\/SCF ab initio calculations. Electron density representations created by TAE reconstruction are designed to allow numerous molecular properties to be quickly assessed with results similar to those obtained at the HF\\/6-31 + G? level of theory. While Hartree-Fock calculations using this basis set do not provide state-of-the-art

Curt M. Breneman; Tracy R. Thompson; Marlon Rhem; Mei Dung

1995-01-01

143

Gas Atomization Precursor Powder Approach for Simplified Large-Scale Production of Oxide Dispersion  

SciTech Connect

Oxide dispersion strengthened (ODS) Ni-based alloys show promise for future energy applications that require high-temperature and oxidation resistant properties. Gas atomization reaction synthesis (GARS), with a mixed (Ar/O{sub 2}) atomization gas, is being developed as a simplified route for producing ODS precursor powders. Internal oxidation studies determined Ni-Cr-Y-(Hf or Ti) containing systems are suitable for production of ODS alloys via hot consolidation, which is used to encourage oxygen exchange between the less stable surface oxide phase and reactive alloying elements, resulting in highly stable nano-metric dispersoid formation. Size control of powders is key to optimizing microstructural and strengthening features. Aspiration and, previously, water modeling experiments were used to develop atomization process parameters that encourage controlled powder production while maintaining reduced operating costs when implemented on an industrial scale. For an increase in pour tube extension: aspiration base pressure at any given operating pressure was found to decrease while wake closure pressure was found to increase. Aspiration hysteresis was observed as recorded previously in the literature. Light emission was observed above wake closure pressures.

Meyer, John; Anderson, Iver; Rieken, Joel; Byrd, David

2011-04-01

144

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

NASA Astrophysics Data System (ADS)

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.

Pechkis, Joseph A.; Fatemi, Fredrik K.

2012-06-01

145

Precision displacement reference system  

DOEpatents

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.

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

2000-02-22

146

XY displacement device  

Microsoft Academic Search

An XY-displacement device (1) with a four-fold symmetry comprises a reference frame (10); an object mount (20) for holding an object (22) to be displaced; an X-manipulator (100) coupled between the reference frame (10) and the object mount (20), which provides a rigid coupling between the object mount (20) and a piezoelectric X-actuator (140), allows a Y-displacement of the object

W. C. Heerens; C. D. Laham; A. E. Holman

1997-01-01

147

Large-scale circulation of atomic oxygen in the MLT region  

NASA Astrophysics Data System (ADS)

The atomic oxygen green line airglow at 557.7 nm, originating from the O(1S) level, has a long history of observation, beginning with John Strutt (Lord Rayleigh IV). He drew attention to its variability, a topic that has puzzled successive investigators for decades. More recently, global observations of the oxygen airglow, interpreted with the help of global circulation models have provided some understanding. Zonally averaged satellite observations clearly demonstrate the dynamical influence of tides on the daily variations. Global maps for a single day show a longitudinal variation results from planetary waves. For a single ground-station, the observations are influenced by both, involving variability over days or weeks. During the course of the year both annual and semi-annual components of the variation have been identified. In the present investigation these are studied using data from the WIND Imaging Interferometer (WINDII) on the Upper Atmosphere Research Satellite, and model results from the TIME-GCM model. The annual variation can be described in terms of a rapid buildup of atomic oxygen in the fall, manifested as high airglow levels at polar latitudes in early winter that decay gradually during the winter period, and are abruptly terminated by a strong atomic oxygen depletion in spring that has been called the springtime transition. The summer values remain low until the sudden autumn rise that can be called the autumnal transition. However, the observations show significant differences between the northern and southern hemispheres. The semi-annual variation dominates at latitudes below 30 and appears to be the result of changes in the mixing intensity that may be linked to the semi-annual variation in the amplitude of the diurnal tide.

Shepherd, G.; Liu, G.; Roble, R.

148

On the performance of large Gaussian basis sets for the computation of total atomization energies  

NASA Technical Reports Server (NTRS)

The total atomization energies of a number of molecules have been computed using an augmented coupled-cluster method and (5s4p3d2f1g) and 4s3p2d1f) atomic natural orbital (ANO) basis sets, as well as the correlation consistent valence triple zeta plus polarization (cc-pVTZ) correlation consistent valence quadrupole zeta plus polarization (cc-pVQZ) basis sets. The performance of ANO and correlation consistent basis sets is comparable throughout, although the latter can result in significant CPU time savings. Whereas the inclusion of g functions has significant effects on the computed Sigma D(e) values, chemical accuracy is still not reached for molecules involving multiple bonds. A Gaussian-1 (G) type correction lowers the error, but not much beyond the accuracy of the G1 model itself. Using separate corrections for sigma bonds, pi bonds, and valence pairs brings down the mean absolute error to less than 1 kcal/mol for the spdf basis sets, and about 0.5 kcal/mol for the spdfg basis sets. Some conclusions on the success of the Gaussian-1 and Gaussian-2 models are drawn.

Martin, J. M. L.

1992-01-01

149

Compressed Facade Displacement Maps  

Microsoft Academic Search

We describe an approach to render massive urban models. To prevent a memory transfer bottleneck, we propose to render the models from a compressed representation directly. Our solution is based on rendering crude building outlines as polygons and generating details by ray-tracing displacement maps in the fragment shader. We demonstrate how to compress a displacement map so that a decompression

Saif Ali; Jieping Ye; Anshuman Razdan; Peter Wonka

2009-01-01

150

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)

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.

Casper, A. F.

2005-05-01

151

Hydrogen atom with a Yukawa potential: Perturbation theory and continued-fractions--Pade approximants at large order  

SciTech Connect

A simple power-series method is developed to calculate to large order the Rayleigh-Schroedinger perturbation expansions for energy levels of a hydrogen atom with a Yukawa-type screened Coulomb potential. Perturbation series for the 1s, 2s, and 2p levels, shown not to be of the Stieltjes type, are calculated to 100th order. Nevertheless, the poles of the Pade approximants to these series generally avoid the region of the positive real axis 0 < lambda < lambda(, where lambda( represents the coupling constant threshold. As a result, the Pade sums afford accurate approximations to E(lambda) in this domain. The continued-fraction representations to these perturbation series have been accurately calculated to large (100th) order and demonstrate a curious ''quasioscillatory,'' but non-Stieltjes, behavior. Accurate values of E(lambda) as well as lambda( for the 1s, 2s, and 2p levels are reported.

Vrscay, E.R.

1986-02-01

152

A Googol of Atoms? A Directed Case in Estimation and Large Numbers  

NSDL National Science Digital Library

What is a googol?  Invented by Edward Kasner, an American mathematician who popularized the number in his 1940 book, Mathematics and the Imagination, it is a 1 followed by a hundred zeros. This directed case in estimation and very large numbers was written for a college-level introductory astronomy course, although it could also be used in a variety of other courses in chemistry, planetary science, biology, and mathematics.

Shawl, Stephen J.

2003-01-01

153

Conflict, displacement and health in the Middle East.  

PubMed

Displacement is a hallmark of modern humanitarian emergencies. Displacement itself is a traumatic event that can result in illness or death. Survivors face challenges including lack of adequate shelter, decreased access to health services, food insecurity, loss of livelihoods, social marginalisation as well as economic and sexual exploitation. Displacement takes many forms in the Middle East and the Arab World. Historical conflicts have resulted in long-term displacement of Palestinians. Internal conflicts have driven millions of Somalis and Sudanese from their homes. Iraqis have been displaced throughout the region by invasion and civil strife. In addition, large numbers of migrants transit Middle Eastern countries or live there illegally and suffer similar conditions as forcibly displaced people. Displacement in the Middle East is an urban phenomenon. Many displaced people live hidden among host country populations in poor urban neighbourhoods - often without legal status. This represents a challenge for groups attempting to access displaced populations. Furthermore, health information systems in host countries often do not collect data on displaced people, making it difficult to gather data needed to target interventions towards these vulnerable populations. The following is a discussion of the health impacts of conflict and displacement in the Middle East. A review was conducted of published literature on migration and displacement in the region. Different cases are discussed with an emphasis on the recent, large-scale and urban displacement of Iraqis to illustrate aspects of displacement in this region. PMID:21590557

Mowafi, Hani

2011-01-01

154

Elucidating common structural features of human pathogenic variations using large-scale atomic-resolution protein networks.  

PubMed

With the rapid growth of structural genomics, numerous protein crystal structures have become available. However, the parallel increase in knowledge of the functional principles underlying biological processes, and more specifically the underlying molecular mechanisms of disease, has been less dramatic. This notwithstanding, the study of complex cellular networks has made possible the inference of protein functions on a large scale. Here, we combine the scale of network systems biology with the resolution of traditional structural biology to generate a large-scale atomic-resolution interactome-network comprising 3,398 interactions between 2,890 proteins with a well-defined interaction interface and interface residues for each interaction. Within the framework of this atomic-resolution network, we have explored the structural principles underlying variations causing human-inherited disease. We find that in-frame pathogenic variations are enriched at both the interface and in the interacting domain, suggesting that variations not only at interface "hot-spots," but in the entire interacting domain can result in alterations of interactions. Further, the sites of pathogenic variations are closely related to the biophysical strength of the interactions they perturb. Finally, we show that biochemical alterations consequent to these variations are considerably more disruptive than evolutionary changes, with the most significant alterations at the protein interaction interface. PMID:24599843

Das, Jishnu; Lee, Hao Ran; Sagar, Adithya; Fragoza, Robert; Liang, Jin; Wei, Xiaomu; Wang, Xiujuan; Mort, Matthew; Stenson, Peter D; Cooper, David N; Yu, Haiyuan

2014-05-01

155

The Embedded Atom Model and large-scale MD simulation of tin under shock loading  

NASA Astrophysics Data System (ADS)

The goal of the work was to develop an interatomic potential, that can be used in large-scale classical MD simulations to predict tin properties near the melting curve, the melting curve itself, and the kinetics of melting and solidification when shock and ramp loading. According to phase diagram, shocked tin melts from bcc phase, and since the main objective was to investigate melting, the EAM was parameterized for bcc phase. The EAM was optimized using isothermal compression data (experimental at T=300 K and ab-initio at T=0 K for bcc, fcc, bct structures), experimental and QMD data on the Hugoniot and on the melting at elevated pressures. The Hugoniostat calculations centred at ?-tin at ambient conditions showed that the calculated Hugoniot is in good agreement with experimental and QMD data above p-bct transition pressure. Calculations of overcooled liquid in pressure range corresponding to bcc phase showed crystallization into bcc phase. Since the principal Hugoniot of tin originates from the ?-tin that is not described by this EAM the special initial state of bcc samples was constructed to perform large-scale MD simulations of shock loading.

Sapozhnikov, F. A.; Ionov, G. V.; Dremov, V. V.; Soulard, L.; Durand, O.

2014-05-01

156

Residential Displacement: An Update.  

National Technical Information Service (NTIS)

The report provides an assessment of the displacement phenomenon, based mainly on the results of HUD-sponsored research and technical assistance projects. A summary of these projects' results addresses the neighborhood revitalization process and displacem...

M. S. Davis G. Ferguson

1981-01-01

157

Advanced Triangulation Displacement Sensors  

NASA Technical Reports Server (NTRS)

Advanced optoelectronic triangulation displacement sensors undergoing development. Highly miniaturized, more stable, more accurate, and relatively easy to use. Incorporate wideband electronic circuits suitable for real-time monitoring and control of displacements. Measurements expected to be accurate to within nanometers. In principle, sensors mass-produced at relatively low unit cost. Potential applications numerous. Possible industrial application in measuring runout of rotating shaft or other moving part during fabrication in "zero-defect" manufacturing system, in which measured runout automatically corrected.

Poteet, Wade M.; Cauthen, Harold K.

1996-01-01

158

Large-dimension configuration-interaction calculations of positron binding to the group-II atoms  

SciTech Connect

The configuration-interaction (CI) method is applied to the calculation of the structures of a number of positron binding systems, including e{sup +}Be, e{sup +}Mg, e{sup +}Ca, and e{sup +}Sr. These calculations were carried out in orbital spaces containing about 200 electron and 200 positron orbitals up to l=12. Despite the very large dimensions, the binding energy and annihilation rate converge slowly with l, and the final values do contain an appreciable correction obtained by extrapolating the calculation to the l{yields}{infinity} limit. The binding energies were 0.00317 hartree for e{sup +}Be, 0.0170 hartree for e{sup +}Mg, 0.0189 hartree for e{sup +}Ca, and 0.0131 hartree for e{sup +}Sr.

Bromley, M. W. J.; Mitroy, J. [Department of Physics, San Diego State University, San Diego, California 92182 (United States); Faculty of Technology, Charles Darwin University, Darwin NT 0909 (Australia)

2006-03-15

159

Large nonlinear optical rectification in atomic hexagonal layers with broken space inversion symmetry  

NASA Astrophysics Data System (ADS)

Motivated by possible applications in optoelectronics, we consider nonlinear optical rectification (NOR) in two planar hexagonal lattice structures with broken space inversion symmetry—namely, in graphene epitaxially grown on a SiC substrate and in boronitrene (a monolayer of BN). For both structures, we calculate the second-order nonlinear optical susceptibility ?(2)(0?, - ?) relevant to the NOR effect and evaluate a bias voltage V0 appearing at the structure terminals under strong laser irradiation. We show that the reason for the ?(2)(0?, - ?) being nonvanishing in the examined structures is their sublattice (inversion) asymmetry combined with the trigonal symmetry of their ?-electron energy bands near the corners of the hexagonal Brillouin zone of those structures. In spite of being rather small, the trigonal warping of the energy bands involved is found to provide a remarkably large magnitude of the NOR susceptibility, reaching the order of 5 × 10-4 esu for the graphene/SiC overlayer system when the pump photon energy ?? approaches the bandgap energy EG (?0.26 eV) of the overlying graphene. For a graphene sample of a few microns length, irradiated by a normally incident laser beam with a relatively moderate power density of 10 kW cm-2, the corresponding optical rectification voltage V0 is estimated to be as large as several millivolts. Moreover, the sign of the voltage (i.e., its polarity) can be sharply reversed by sweeping the photon energy through the inter-?-band resonance condition ?? = EG. This frequency-controlled optical switching, if realized, will be a potent technique for graphene-based photonics and optoelectronics.

Margulis, Vl A.; Muryumin, E. E.; Gaiduk, E. A.

2013-10-01

160

Internal displacement in Burma.  

PubMed

The internal displacement of populations in Burma is not a new phenomenon. Displacement is caused by numerous factors. Not all of it is due to outright violence, but much is a consequence of misguided social and economic development initiatives. Efforts to consolidate the state by assimilating populations in government-controlled areas by military authorities on the one hand, while brokering cease-fires with non-state actors on the other, has uprooted civilian populations throughout the country. Very few areas in which internally displaced persons (IDPs) are found are not facing social turmoil within a climate of impunity. Humanitarian access to IDP populations remains extremely problematic. While relatively little information has been collected, assistance has been focused on targeting accessible groups. International concern within Burma has couched the problems of displacement within general development modalities, while international attention along its borders has sought to contain displacement. With the exception of several recent initiatives, few approaches have gone beyond assistance and engaged in the prevention or protection of the displaced. PMID:11026156

Lanjouw, S; Mortimer, G; Bamforth, V

2000-09-01

161

Large-Area Atomically Thin MoS2 Nanosheets Prepared Using Electrochemical Exfoliation.  

PubMed

Molybdenum disulfide (MoS2) is an extremely intriguing material because of its unique electrical and optical properties. The preparation of large-area and high-quality MoS2 nanosheets is an important step in a wide range of applications. This study demonstrates that monolayer and few-layer MoS2 nanosheets can be obtained from electrochemical exfoliation of bulk MoS2 crystals. The lateral size of the exfoliated MoS2 nanosheets is in the 5-50 ?m range, which is much larger than that of chemically or liquid-phase exfoliated MoS2 nanosheets. The MoS2 nanosheets undergo low levels of oxidation during electrochemical exfoliation. In addition, microscopic and spectroscopic characterizations indicate that the exfoliated MoS2 nanosheets are of high quality and have an intrinsic structure. A back-gate field-effect transistor was fabricated using an exfoliated monolayer MoS2 nanosheet. The on/off current ratio is over 10(6), and the field-effect mobility is approximately 1.2 cm(2) V(-1) s(-1); these values are comparable to the results for micromechanically exfoliated MoS2 nanosheets. The electrochemical exfoliation method is simple and scalable, and it can be applied to exfoliate other transition metal dichalcogenides. PMID:24937086

Liu, Na; Kim, Paul; Kim, Ji Heon; Ye, Jun Ho; Kim, Sunkook; Lee, Cheol Jin

2014-07-22

162

Displacement of large-scale open solar magnetic fields from the zone of active longitudes and the heliospheric storm of November 3-10, 2004: 1. The field dynamics and solar activity  

NASA Astrophysics Data System (ADS)

The dynamics of the large-scale open field and solar activity at the second stage of the MHD process, including the origination and disappearance of the four-sector structure during the decline phase of cycle 23 (the stage when the blocking field is displaced from the main zone of active longitudes), has been considered. Extremely fast changes in the scales of one of new sectors (from an extremely small sector (“singularity”) to a usual sector that originated after the uniform expansion (“explosion”) of singularity with a “kick” into the zone of active longitudes, westward motion of the MHD disturbance front in the direction of solar rotation, and formation of an active quasi-rigidly corotating sector boundary responsible for the heliospheric storm of November 2004) have been detected in the field dynamics. It has been indicated that a very powerful group of sunspots AR 10656 (which disappeared after the explosion) with an area of up to 1540 ppmh (part per million hemisphere), a considerable deficit of the external energy release, and zero geoeffectiveness in spite of the closeness to the Earth helioprojection existed within singularity. It has been assumed that the energy escaped from this group with effort owing to the interaction between coronal ejections and narrow sector walls (singularity), and a considerable part of the energy was released in the outer layers of the convective zone, as a result of which singularity exploded and this explosion was accompanied by the above effects in the large-scale field and solar activity.

Ivanov, K. G.

2010-06-01

163

A force platform for large human displacements.  

PubMed

This paper provides details of a force platform assembly suitable for measuring the magnitude, position and direction of ground reaction forces for manual handling tasks involving several footsteps in any horizontal direction. An approach to increase the natural frequency with the use of a vibration absorber is used; this frequency was found to be 41+/-2 Hz. The results show a maximum error of 22 N (2% of the full scale output) when a person performs repetitive movements from a squat position to a full extension and back to the squat position. Static tests show the maximal errors to be, vertically, 1.5% of the full scale output (1818+/-33 N), and horizontally, 4.9% of the full scale output (1177+/-6 N). PMID:11413067

Desjardins, P; Gagnon, M

2001-03-01

164

Fluid structure interaction with large structural displacements  

Microsoft Academic Search

The calculation of viscous flows inside deformable structures faces major difficulties when enforcing the kinematic compatibility at the fluid structure interface and updating the geometry of the domain. This paper proposes to overcome these problems by considering the fluid and the structure as a unique continuous medium, to be studied in a fixed reference configuration. The resulting problem is then

P. Le Tallec; J. Mouro

2001-01-01

165

Force based displacement measurement in micromechanical devices  

SciTech Connect

We demonstrate how force detection methods based on atomic force microscopy can be used to measure displacement in micromechanical devices. We show the operation of a simple microfabricated accelerometer, the proof mass of which incorporates a tip which can be moved towards an opposing surface. Both noncontact operation using long range electrostatic forces and tapping mode operation are demonstrated. The displacement sensitivity of the present device using feedback to control the tip-surface separation is approximately 1 nm. {copyright} 2001 American Institute of Physics.

O {close_quote}Shea, S. J.; Ng, C. K.; Tan, Y. Y.; Xu, Y.; Tay, E. H.; Chua, B. L.; Tien, N. C.; Tang, X. S.; Chen, W. T.

2001-06-18

166

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, Marshall G. (Woodside, CA)

1985-01-01

167

Water displacement mercury pump  

DOEpatents

A water displacement mercury pump has a fluid inlet conduit and diffuser, a valve, a pressure cannister, and a fluid outlet conduit. The valve has a valve head which seats in an opening in the cannister. The entire assembly is readily insertable into a process vessel which produces mercury as a product. As the mercury settles, it flows into the opening in the cannister displacing lighter material. When the valve is in a closed position, the pressure cannister is sealed except for the fluid inlet conduit and the fluid outlet conduit. Introduction of a lighter fluid into the cannister will act to displace a heavier fluid from the cannister via the fluid outlet conduit. The entire pump assembly penetrates only a top wall of the process vessel, and not the sides or the bottom wall of the process vessel. This insures a leak-proof environment and is especially suitable for processing of hazardous materials.

Nielsen, M.G.

1984-04-20

168

Bragg optical displacement sensor  

NASA Astrophysics Data System (ADS)

A novel optical displacement sensor based on Bragg effect is described. A green light bema was used to excite a Rh6G dye solution in Shank type geometry. The beam was split up by a dielectric mirror and the two equal intensity vertically polarized light beams were folded by two mirrors to interfere in the dye cell. The lasing wavelength was found to be a precise function of the half angle between the beams. The vibrating body was attached to one of the folding mirror. In normal operation the lasing line wavelength was unchanged but during mirror vibration corresponding to this 1 degree was 87 micrometers . The sensor resolution was about 1.3 angstrom/micrometers . This ultrashell displacement sensor can be used to determine the frequency of vibration or simple displacements in ultraprecise applications.

Khan, Nasrullah

1999-11-01

169

Optical displacement sensor  

DOEpatents

An optical displacement sensor is disclosed which uses a vertical-cavity surface-emitting laser (VCSEL) coupled to an optical cavity formed by a moveable membrane and an output mirror of the VCSEL. This arrangement renders the lasing characteristics of the VCSEL sensitive to any movement of the membrane produced by sound, vibrations, pressure changes, acceleration, etc. Some embodiments of the optical displacement sensor can further include a light-reflective diffractive lens located on the membrane or adjacent to the VCSEL to control the amount of lasing light coupled back into the VCSEL. A photodetector detects a portion of the lasing light from the VCSEL to provide an electrical output signal for the optical displacement sensor which varies with the movement of the membrane.

Carr, Dustin W. (Albuquerque, NM)

2008-04-08

170

Spectral properties of displacement models  

NASA Astrophysics Data System (ADS)

The recent study of Schrodinger operators with random potentials has provided significant insight into our understanding of the electronic properties of disordered media. This work presents new results concerning the spectrum of a class of random operators called displacement models. Such models may be used to model solids in which the positions of the individual atoms are randomly perturbed from an ideal periodic lattice. In particular, we will provide a characterization of the almost sure spectral minimum of the random displacement model, bounds on the integrated density of states, and a rigourous proof of the lack of classical Lifshitz tails under suitable assumptions on the random parameters. The fundamental tool used throughout the work is a quite general phenomenon in the spectral theory of Neumann problems, which we dub "bubbles tend to the boundary." How should a given compactly supported potential be placed into a bounded domain so as to minimize or maximize the first Neumann eigenvalue of the Schrdinger operator on this domain? For square or rectangular domains and reflection symmetric potentials, we show that the first Neumann eigenvalue is minimized when the potential sits in one of the corners of the domain and is maximized when it sits in the center of the domain. With different methods we also show a corresponding result for smooth strictly convex domains.

Baker, Steven

171

Internally displaced persons.  

PubMed

There were estimated to be over 20 million internally displaced persons (IDPs) at the end of 1999, a number that surpasses global estimates of refugees. Displacement exposes IDPs to new hazards and accrued vulnerability. These dynamics result in greater risk for the development of illness and death. Often, access of IDPs to health care and humanitarian assistance is excluded deliberately by conflicting parties. Furthermore, the arrival of IDPs into another community or region strains local health systems, and the host population ends up sharing the sufferings of the internally displaced. Health outcomes are dismaying. From a health perspective, the best option is to avoid human displacement. WHO contributes to the prevention of displacement by working for sustainable development. Placing health high on the political agenda helps maintain stability, and thereby, reduce the likelihood for displacement. Primary responsibility for assisting IDPs, irrespective of the cause, rests with the national government. However, where the government is unwilling or unable to provide the necessary aid, the international humanitarian community must step in, with WHO playing a major role in the health sector. There is consensus among the partners of the World Health Organization (WHO) that, in emergencies, the WHO must: 1) take the lead in rapid health assessment, epidemiological and nutritional surveillance, epidemic preparedness, essential drugs management, control of communicable diseases, and physical and psychosocial rehabilitation; and 2) provide guidelines and advice on nutritional requirements and rehabilitation, immunisation, medical relief items, and reproductive health. If the vital health needs of IDPs--security, food, water, shelter, sanitation and household items--are not satisfied, the provision of health services alone cannot save lives. Community participation is essential, and community participation implies bolstering the assets and capacities of the beneficiaries. PMID:11875794

Leus, X; Wallace, J; Loretti, A

2001-01-01

172

Identification and morphology of point defect clusters created in displacement cascades in ?-zirconium  

NASA Astrophysics Data System (ADS)

Atomic scale computer simulation of high-energy displacement cascades in ?-zirconium has been carried out for a wide range of primary knock-on atom energy (10-25 keV) and temperature (100-600 K). A large number of vacancy and self-interstitial atom (SIA) clusters of various shapes and sizes was generated in more than 240 cascades. In spite of the variety of cluster structures, they can be categorized into three distinct configurations for vacancy and SIA clusters. Internal atom arrangements for all point defect clusters have been established and the type of stacking faults that can be assigned to vacancy clusters identified. The explanation of different relaxation patterns of prismatic vacancy loops occupying either even or odd number of neighbouring close-packed planes is suggested. Transformation of the pyramid-like vacancy cluster with a basal-plane extrinsic fault into prismatic vacancy loop is considered.

Voskoboinikov, R. E.; Osetsky, Yu. N.; Bacon, D. J.

2006-01-01

173

Efficient methods for including quantum effects in Monte Carlo calculations of large systems: Extension of the displaced points path integral method and other effective potential methods to calculate properties and distributions  

NASA Astrophysics Data System (ADS)

We present a procedure to calculate ensemble averages, thermodynamic derivatives, and coordinate distributions by effective classical potential methods. In particular, we consider the displaced-points path integral (DPPI) method, which yields exact quantal partition functions and ensemble averages for a harmonic potential and approximate quantal ones for general potentials, and we discuss the implementation of the new procedure in two Monte Carlo simulation codes, one that uses uncorrelated samples to calculate absolute free energies, and another that employs Metropolis sampling to calculate relative free energies. The results of the new DPPI method are compared to those from accurate path integral calculations as well as to results of two other effective classical potential schemes for the case of an isolated water molecule. In addition to the partition function, we consider the heat capacity and expectation values of the energy, the potential energy, the bond angle, and the OH distance. We also consider coordinate distributions. The DPPI scheme performs best among the three effective potential schemes considered and achieves very good accuracy for all of the properties considered. A key advantage of the effective potential schemes is that they display much lower statistical sampling variances than those for accurate path integral calculations. The method presented here shows great promise for including quantum effects in calculations on large systems.

Mielke, Steven L.; Dinpajooh, Mohammadhasan; Siepmann, J. Ilja; Truhlar, Donald G.

2013-01-01

174

Efficient methods for including quantum effects in Monte Carlo calculations of large systems: extension of the displaced points path integral method and other effective potential methods to calculate properties and distributions.  

PubMed

We present a procedure to calculate ensemble averages, thermodynamic derivatives, and coordinate distributions by effective classical potential methods. In particular, we consider the displaced-points path integral (DPPI) method, which yields exact quantal partition functions and ensemble averages for a harmonic potential and approximate quantal ones for general potentials, and we discuss the implementation of the new procedure in two Monte Carlo simulation codes, one that uses uncorrelated samples to calculate absolute free energies, and another that employs Metropolis sampling to calculate relative free energies. The results of the new DPPI method are compared to those from accurate path integral calculations as well as to results of two other effective classical potential schemes for the case of an isolated water molecule. In addition to the partition function, we consider the heat capacity and expectation values of the energy, the potential energy, the bond angle, and the OH distance. We also consider coordinate distributions. The DPPI scheme performs best among the three effective potential schemes considered and achieves very good accuracy for all of the properties considered. A key advantage of the effective potential schemes is that they display much lower statistical sampling variances than those for accurate path integral calculations. The method presented here shows great promise for including quantum effects in calculations on large systems. PMID:23298031

Mielke, Steven L; Dinpajooh, Mohammadhasan; Siepmann, J Ilja; Truhlar, Donald G

2013-01-01

175

Needs of Displaced Homemakers.  

ERIC Educational Resources Information Center

As part of its five-year state plan for vocational education, the California State Department of Education and the Chancellor's Office of the California Community Colleges commissioned a study of the needs of displaced homemakers. (These women's needs were relevant to the state's plans for vocational education because the Education Amendments of…

Arnold, Carolyn; Marzone, Jean

176

Stability of Helium Clusters during Displacement Cascades  

SciTech Connect

The interaction of displacement cascades with helium-vacancy clusters is investigated using molecular dynamics simulations. The He-vacancy clusters initially consist of 20 vacancies with a Helium-to-vacancy ratio ranging from 0.2 to 3. The primary knock-on atom (PKA) energy, Ep, varies from 2 keV to 10 keV, and the PKA direction is chosen such that a displacement cascade is able to directly interact with a helium-vacancy cluster. The simulation results show that the effect of displacement cascades on a helium-vacancy cluster strongly depends on both the helium-to-vacancy ratio and the PKA energy. For the same PKA energy, the size of helium-vacancy clusters increases with the He/V ratio, but for the same ratio, the cluster size changes more significantly with increasing PKA energy. It has been observed that the He-vacancy clusters can be dissolved when the He/V ratio less than 1, but they are able to re-nucleate during the thermal spike phase, forming small He-V nuclei. When the He/V ratio is larger than 1, the He-V clusters can absorb a number of vacancies produced by displacement cascades, forming larger He-V clusters. These results are discussed in terms of PKA energy, helium-to-vacancy ratio, number of vacancies produced by cascades, and mobility of helium atoms.

Yang, Li; Zu, Xiaotao T.; Xiao, H. Y.; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Wang, Zhiguo; Liu, K. Z.

2007-02-01

177

First-order character of the displacive structural transition in BaWO4  

NASA Astrophysics Data System (ADS)

Nearly all displacive transitions have been considered to be continuous or second order, and the rigid unit mode (RUM) provides a natural candidate for the soft mode. However, in-situ X-ray diffraction and Raman measurements show clearly the first-order evidences for the scheelite-to-fergusonite displacive transition in BaWO4: a 1.6% volume collapse, coexistence of phases, and hysteresis on release of pressure. Such first-order signatures are found to be the same as the soft modes in BaWO4, which indicates the scheelite-to-fergusonite displacive phase transition hides a deeper physical mechanism. By the refinement of atomic displacement parameters, we further show that the first-order character of this phase transition stems from a coupling of large compression of soft BaO8 polyhedrons to the small displacive distortion of rigid WO4 tetrahedrons. Such a coupling will lead to a deeper physical insight in the phase transition of the common scheelite-structured compounds.

Tan, Da-Yong; Xiao, Wan-Sheng; Zhou, Wei; Chen, Ming; Xiong, Xiao-Lin; Song, Mao-Shuang

2012-08-01

178

Development of a large-range atomic force microscope measuring system for optical free form surface characterization  

NASA Astrophysics Data System (ADS)

In this paper, a large-range atomic force microscope (AFM) measuring system is developed for optical free form surface characterization. Based on the self-sensing tuning fork probe, a compact AFM head is developed, which is easy to combine with a scanning stage. Depending on the probe's unique structure and the usage of dynamic working mode, the tip-sample interaction force is reduced, improving the system's dynamic response performance. A two-platform structure is applied in the system, which combines a PZT stage with a motor driving platform. A dual feedback strategy is applied to ensure a measuring range up to 25 mm × 25 mm × 5 mm. The system includes three laser interferometers to make the measuring data traced to the ‘meter’ definition. A standard one-dimensional grating is tested to show the performance of the system. A millimeter scale optical free form surface with a sinusoidal structure array is measured relying on the two-platform structure implemented. The high frequency information and low frequency information of the sample are separated automatically, which represent the profile and roughness, respectively.

Guo, Tong; Wang, Longlong; Chen, Jinping; Fu, Xing; Hu, Xiaotang

2012-11-01

179

Features of the atomic structure of the impurities complexes in the irradiated materials doped by the elements with a large atomic radii.  

National Technical Information Service (NTIS)

The interaction between impurity atoms and radiation-induced defects in Ni(Sc), Ni(Ti), Ni(Pr) and Ni(Y) alloys irradiated with 5 and 30 MeV electrons were studied by the residual resistivity measurements, and the methods of reciprocal damage rate and pos...

I. M. Neklyudov A. N. Sleptsov I. G. Marchenko S. N. Sleptsov

1995-01-01

180

Displacement and Velocity Ratios  

NSDL National Science Digital Library

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.

Bourassa, James; Rosz, John

2011-04-05

181

Optical displacement measuring device  

Microsoft Academic Search

Theoretical considerations of a lightweight, frictionless, optical displacement measuring device (ODMD) are discussed. Experimental results show its resolution and accuracy to be better than 2.5 x 10 to the -8th m with a linear range of 7.5 x 10 to the -5th m, and less than 0.2% change of voltage signal in 600 hours; it has high cycling ability, no

G. F. Weissmann; H. L. Carter Jr.; R. R. Hart

1979-01-01

182

Displacement chromatography applied to trace component analysis  

SciTech Connect

Displacement chromatography has been used primarily for the isolation of relatively large quantities of materials in preparative scale separations. The authors show that it also offers advantages for the enrichment of trace components. During displacement development, significant compression of the trace component bands occurs. This enrichment is studied both experimentally and theoretically. The theoretical model is based on the solution of the mass balance equations for nonlinear chromatography, assuming competitive Langmuir isotherms. The system studied experimentally consisted of parts-per-million levels of {beta}-naphthylamine and an impurity of the naphthylamine as the sample and diethyl phthalate as the displacer. The band profiles of the trace components were monitored by fluorescence detection while the displacer was monitored by UV absorbance. Wavelengths were chosen such that the profiles of the sample and the displacer could be monitored independently. Trace enrichment by band compression was achieved by increasing the displacer concentration. Experimental results show very narrow bands at enhanced concentrations as compared to the relatively broad Gaussian-shaped profiles observed in linear elution chromatography. The experimental results are in agreement with theoretical predictions of peak shape.

Ramsey, R.; Katti, A.M.; Guiochon, G. (Univ. of Tennessee, Knoxville (USA) Oak Ridge National Laboratory, TN (USA))

1990-12-01

183

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

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

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

2009-01-01

184

Evidencing `Tight Bound States' in the Hydrogen Atom:. Empirical Manipulation of Large-Scale XD in Violation of QED  

NASA Astrophysics Data System (ADS)

In this work we extend Vigier's recent theory of `tight bound state' (TBS) physics and propose empirical protocols to test not only for their putative existence, but also that their existence if demonstrated provides the 1st empirical evidence of string theory because it occurs in the context of large-scale extra dimensionality (LSXD) cast in a unique M-Theoretic vacuum corresponding to the new Holographic Anthropic Multiverse (HAM) cosmological paradigm. Physicists generally consider spacetime as a stochastic foam containing a zero-point field (ZPF) from which virtual particles restricted by the quantum uncertainty principle (to the Planck time) wink in and out of existence. According to the extended de Broglie-Bohm-Vigier causal stochastic interpretation of quantum theory spacetime and the matter embedded within it is created annihilated and recreated as a virtual locus of reality with a continuous quantum evolution (de Broglie matter waves) governed by a pilot wave - a `super quantum potential' extended in HAM cosmology to be synonymous with the a `force of coherence' inherent in the Unified Field, UF. We consider this backcloth to be a covariant polarized vacuum of the (generally ignored by contemporary physicists) Dirac type. We discuss open questions of the physics of point particles (fermionic nilpotent singularities). We propose a new set of experiments to test for TBS in a Dirac covariant polarized vacuum LSXD hyperspace suggestive of a recently tested special case of the Lorentz Transformation put forth by Kowalski and Vigier. These protocols reach far beyond the recent battery of atomic spectral violations of QED performed through NIST.

Amoroso, Richard L.; Vigier, Jean-Pierre

2013-09-01

185

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS  

Microsoft Academic Search

Direct pump control of hydraulic systems is more energy efficient than throttle valve based methods to control hydra ulic systems. This requires variable displacement pumps that are responsive and capable of electronic control. Such Electronic Displacement Controlled (EDC) pumps tend to be significantl y larger, heavier and more expensive than fixed displacement c oun- terparts. In addition, achievable control bandwidths

Perry Y. Li; Cassie Y. Li; Thomas R. Chase

186

DISPLACEMENT SPECTRA FOR SEISMIC DESIGN  

Microsoft Academic Search

Displacement-based seismic design and assessment of structures require the reliable definition of displacement spectra for a wide range of periods and damping levels. The displacement spectra derived from acceleration spectra in existing seismic codes do not provide a suitable answer and there are no existing frequency-dependent attenuation relationships derived specifically for this purpose. Using a carefully processed dataset of European

JULIAN J. BOMMER; AMR S. ELNASHAI

1999-01-01

187

Limitations on the Extent of Off-Center Displacements in Tbmno(3) From EXAFS Measurements  

SciTech Connect

We present extended x-ray-absorption fine structure (EXAFS) data at the Mn K and Tb L{sub 3} edges that provide upper limits on the possible displacements of any atoms in TbMnO{sub 3}. The displacements must be less than 0.005--0.01 {angstrom} for all atoms, which eliminates the possibility of moderate distortions (0.02 {angstrom}) with a small c-axis component, but for which the displacements in the ab plane average to zero. Assuming the polarization arises from a displacement of the O2 atoms along the c axis, the measured polarization then leads to an O2 displacement that is at least 6 x 10{sup -4} {angstrom}, well below our experimental limit. Thus, a combination of the EXAFS and the measured electrical polarization indicate that the atomic displacements likely lie in the range 6 x 10{sup -4}--5 x 10{sup 03} {angstrom}.

Bridges, F.; Downs, C.; O'Brien, T.; Jeong, I.-K.; Kimura, T.

2009-06-02

188

Displacement Data Assimilation  

NASA Astrophysics Data System (ADS)

Geometric corrections are blended with nonlinear/non-Gaussian estimation methods to produced improved data assimilation outcomes on problems where features are critical. Problems of this sort are the estimation of hurricane tracks, tracking jet meandering, front propagation, among many others. The geometric correction is made possible by a data preserving map. It makes corrections on phase, primarily, as well as in the amplitude. The displacement assimilation is embedded in the analysis stage of a nonlinear/non-Gaussian Bayesian data assimilation scheme, such as the path integral method. In addition to showing how the method improves upon the results, as compared to more standard methodologies.

Restrepo, J. M.; Rosenthal, S.; Venkataramani, S.

2013-05-01

189

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

SciTech Connect

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.

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

190

Energy dependence of electron damage and displacement threshold energy in 6H silicon carbide  

Microsoft Academic Search

The frequency response of silicon carbide (SiC) light-emitting diodes has been used to measure the energy dependence of displacement damage produced in 6H SiC by energetic electrons. The minimum electron energy required to produce displacement damage was determined to be 108±7 keV, corresponding to an atomic displacement of silicon atoms. For electrons of energies greater than 0.5 MeV, the damage

A. L. Barry; B. Lehmann; D. Fritsch; D. Braeunig

1991-01-01

191

Computer simulation of displacement cascade effects in metals  

NASA Astrophysics Data System (ADS)

Significant advances have been made over the past decade in using computer simulation to investigate the mechanisms associated with defect production by displacement cascades in metals. As reported at COSIRES '92 by Diaz de la Rubia et al. (Rad. Eff. and Def. Sol.130-131 (1994) 39) and COSIRES '94 by Bacon et al. (Nucl. Instrum. and Meth. B102 (1995) 37) a variety of metals of different crystal structure have been modelled over primary-knock-on energies from the threshold for displacement up to several keV, and these studies have shed considerable light on the physics of the cascade process by utilising realistic interatomic potentials with reasonably large model size. They have also shown that the efficiency for production of Frenkel defects is much less than the estimates given by earlier binary-collision models, and that self-interstitial atoms can actually form clusters during the cascade process itself. The present review updates the 1994 paper by discussing more-recent simulations that have gone beyond those referred to above. It includes research dealing with effects on defect formation of cascade energy, irradiation temperature, alloying (solid solutions, ordered alloys and precipitates), and the presence of a nearby surface. Issues such as defect clustering and cascade overlap are also reviewed. The overall aim is to demonstrate that computer simulation still provides a unique means of gaining information on cascade damage processes in metals.

Bacon, D. J.; Calder, A. F.; Gao, F.

192

Adapting to variable prismatic displacement  

NASA Technical Reports Server (NTRS)

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.

Welch, Robert B.; Cohen, Malcolm M.

1989-01-01

193

Displacements, mean-squared displacements, and codisplacements for the calculation of nonequilibrium properties.  

PubMed

We study two situations in which nonequilibrium phenomena can be efficiently calculated using displacements, mean-squared displacements, or codisplacements instead of accumulating velocities or currents. The flow velocity profile for a fluid confined within a pore can be expressed as a sum of displacements within slabs from a molecular dynamics trajectory. In this form, an accurate flow profile is obtained from very sparse sampling of the trajectory. We also recast the linear response theory expression for the flow velocity profile in terms of mean codisplacements and demonstrate that this provides an efficient route for estimating the Green-Kubo expression for the velocity profile. Finally, we calculate the ionic contribution to the frequency-dependent electric susceptibility using dipolar displacements, instead of the conventional current-current correlation function. We expect these methods to be useful for generating transport properties from stored trajectories in very large systems or systems where relaxation times are long. PMID:24791611

Agnihotri, Mithila V; Chen, Si-Han; Beck, Corey; Singer, Sherwin J

2014-07-17

194

Variable displacement blower  

DOEpatents

A blower having a stationary casing for rotatably supporting a rotor assembly having a series of open ended chambers arranged to close against the surrounding walls of the casing. Pistons are slidably mounted within each chamber with the center of rotation of the pistons being offset in regard to the center of rotation of the rotor assembly whereby the pistons reciprocate in the chambers as the rotor assembly turns. As inlet port communicates with the rotor assembly to deliver a working substance into the chamber as the pistons approach a top dead center position in the chamber while an outlet port also communicates with the rotor to exhaust the working substance as the pistons approach a bottom dead center position. The displacement of the blower is varied by adjusting the amount of eccentricity between the center of rotation of the pistons and the center of rotation of the rotor assembly.

Bookout, Charles C. (Niskayuna, NY) [Niskayuna, NY; Stotts, Robert E. (Clifton Park, NY) [Clifton Park, NY; Waring, Douglass R. (Ballston Spa, NY) [Ballston Spa, NY; Folsom, Lawrence R. (Ohain, BE) [Ohain, BE

1986-01-01

195

Displacement measurement of a shaker in an accelerometer calibration system  

Microsoft Academic Search

The vibration displacement of a shaker in an accelerometer calibration system is detected by a Michelson type of a phase quadrature laser interferometer. The interferometric signals are stored in a digital storage scope and transferred to a computer for displacement calculation. Due to the high resolution, fast acquisition speed, and large memory capacity of the scope, this system demonstrates a

Gwo-Sheng Peng; Chien-Ming Wu; Yeu-Jong Huang

1996-01-01

196

Displacement parameter inversion for a novel electromagnetic underground displacement sensor.  

PubMed

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

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

2014-01-01

197

Displacement Parameter Inversion for a Novel Electromagnetic Underground Displacement Sensor  

PubMed Central

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.

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

2014-01-01

198

A cold-atoms based processor for deterministic quantum computation with one qubit in intractably large Hilbert spaces  

NASA Astrophysics Data System (ADS)

We propose the use of Rydberg interactions and ensembles of cold atoms in mixed state for the implementation of a protocol for deterministic quantum computation with one quantum bit that can be readily operated in high dimensional Hilbert spaces. We propose an experimental test for the scalability of the protocol and to study the physics of discord. Furthermore, we explore the possibility of extending to non-trivial unitaries, such as those associated to many-body physics. Finally develop a scheme to add control to cold atom unitaries in order to facilitate their implementation in our proposal.

Mansell, C. W.; Bergamini, S.

2014-05-01

199

CVD synthesis of large-area, highly crystalline MoSe2 atomic layers on diverse substrates and application to photodetectors.  

PubMed

Synthesis of large-area, atomically thin transition metal dichalcogenides (TMDs) on diverse substrates is of central importance for the large-scale fabrication of flexible devices and heterojunction-based devices. In this work, we successfully synthesized a large area of highly-crystalline MoSe2 atomic layers on SiO2/Si, mica and Si substrates using a simple chemical vapour deposition (CVD) method at atmospheric pressure. Atomic force microscopy (AFM) and Raman spectroscopy reveal that the as-grown ultrathin MoSe2 layers change from a single layer to a few layers. Photoluminescence (PL) spectroscopy demonstrates that while the multi-layer MoSe2 shows weak emission peaks, the monolayer has a much stronger emission peak at ?1.56 eV, indicating the transition from an indirect to a direct bandgap. Transmission electron microscopy (TEM) analysis confirms the single-crystallinity of MoSe2 layers with a hexagonal structure. In addition, the photoresponse performance of photodetectors based on MoSe2 monolayer was studied for the first time. The devices exhibit a rapid response of ?60 ms and a good photoresponsivity of ?13 mA/W (using a 532 nm laser at an intensity of 1 mW mm(-2) and a bias of 10 V), suggesting that MoSe2 monolayer is a promising material for photodetection applications. PMID:24965908

Xia, Jing; Huang, Xing; Liu, Ling-Zhi; Wang, Meng; Wang, Lei; Huang, Ben; Zhu, Dan-Dan; Li, Jun-Jie; Gu, Chang-Zhi; Meng, Xiang-Min

2014-07-10

200

A study of the cool gas in the Large Magellanic Cloud. I. Properties of the cool atomic phase - a third H i absorption survey  

NASA Astrophysics Data System (ADS)

The cool atomic interstellar medium of the Large Magellanic Cloud (LMC) seems to be quite different from that in the Milky Way. In a series of three papers we study the properties of the cool atomic hydrogen in the LMC (Paper I), its relation to molecular clouds using SEST-CO-observations (Paper II) and the cooling mechanism of the atomic gas based on ISO-[\\CII]-investigations (Paper III). In this paper we present the results of a third 21 cm absorption line survey toward the LMC carried out with the Australia Telescope Compact Array (ATCA). 20 compact continuum sources, which are mainly in the direction of the supergiant shell LMC 4, toward the surroundings of 30 Doradus and toward the eastern steep \\HI\\ boundary, have been chosen from the 1.4 GHz snapshot continuum survey of Marx et al. We have identified 20 absorption features toward nine of the 20 sources. The properties of the cool \\HI\\ clouds are investigated and are compared for the different regions of the LMC taking the results of Dickey et al. (survey 2) into account. We find that the cool \\HI\\ gas in the LMC is either unusually abundant compared to the cool atomic phase of the Milky Way or the gas is clearly colder (\\Tc\\ ~ 30 K) than that in our Galaxy (\\Tc\\ ~ 60 K). The properties of atomic clouds toward 30 Doradus and LMC 4 suggest a higher cooling rate in these regions compared to other parts of the LMC, probably due to an enhanced pressure near the shock fronts of LMC 4 and 30 Doradus. The detected cool atomic gas toward the eastern steep \\HI\\ boundary might be the result of a high compression of gas at the leading edge. The Australia Telescope is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO.

Marx-Zimmer, M.; Herbstmeier, U.; Dickey, J. M.; Zimmer, F.; Staveley-Smith, L.; Mebold, U.

2000-02-01

201

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

NASA Technical Reports Server (NTRS)

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.

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

1979-01-01

202

Gas Miscible Displacement Enhanced Oil Recovery. Technology Status Report.  

National Technical Information Service (NTIS)

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 densit...

1985-01-01

203

Regenerative rotary displacer Stirling engine  

Microsoft Academic Search

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

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

1996-01-01

204

Feature-based Displacement Mapping  

Microsoft Academic Search

Displacement mapping was originally created as a rendering tool to provide small-scale modulation of an underlying smooth surface. However, it has now emerged as a sculpting tool, to the extent that complex geometry can effectively be added to a scene at rendering time. The attendant complexity of displacement maps is placing increased demands on rendering systems, from quality, perfor- mance,

Xiaohuan Corina Wang; Jérôme Maillot; Eugene Fiume; Victor Ng-thow-hing; Andrew Woo; Sanjay Bakshi

2000-01-01

205

Is fibular fracture displacement consistent with tibiotalar displacement?  

PubMed

We believed open reduction with internal fixation is required for supination-external rotation ankle fractures located at the level of the distal tibiofibular syndesmosis (Lauge-Hanssen SER II and Weber B) with 2 mm or more fibular fracture displacement. The rationale for surgery for these ankle fractures is based on the notion of elevated intraarticular contact pressures with lateral displacement. To diagnose these injuries, we presumed that in patients with a fibular fracture with at least 2 mm fracture displacement, the lateral malleolus and talus have moved at least 2 mm in a lateral direction without medial displacement of the proximal fibula. We reviewed 55 adult patients treated operatively for a supination-external rotation II ankle fracture (2 mm or more fibular fracture displacement) between 1990 and 1998. On standard radiographs, distance from the tibia to the proximal fibula, distance from the tibia to the distal fibula, and displacement at the level of the fibular fracture were measured. These distances were compared preoperatively and postoperatively. We concluded tibiotalar displacement cannot be reliably assessed at the level of the fracture. Based on this and other studies, we believe there is little evidence to perform open reduction and internal fixation of supination-external rotation II ankle fractures. Level of Evidence: Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence. PMID:19582527

van den Bekerom, Michel P J; van Dijk, C Niek

2010-04-01

206

Insect Wing Displacement Measurement Using Digital Holography  

SciTech Connect

Insects in flight have been studied with optical non destructive techniques with the purpose of using meaningful results in aerodynamics. With the availability of high resolution and large dynamic range CCD sensors the so called interferometric digital holographic technique was used to measure the surface displacement of in flight insect wings, such as butterflies. The wings were illuminated with a continuous wave Verdi laser at 532 nm, and observed with a CCD Pixelfly camera that acquire images at a rate of 11.5 frames per second at a resolution of 1392x1024 pixels and 12 Bit dynamic range. At this frame rate digital holograms of the wings were captured and processed in the usual manner, namely, each individual hologram is Fourier processed in order to find the amplitude and phase corresponding to the digital hologram. The wings displacement is obtained when subtraction between two digital holograms is performed for two different wings position, a feature applied to all consecutive frames recorded. The result of subtracting is seen as a wrapped phase fringe pattern directly related to the wing displacement. The experimental data for different butterfly flying conditions and exposure times are shown as wire mesh plots in a movie of the wings displacement.

Aguayo, Daniel D.; Mendoza Santoyo, Fernando; Torre I, Manuel H. de la; Caloca Mendez, Cristian I. [Centro de Investigaciones en Optica A. C., Loma del Bosque 115, Lomas del Campestre, Leon, Guanajuato, Mexico 37150 (Mexico)

2008-04-15

207

Insect Wing Displacement Measurement Using Digital Holography  

NASA Astrophysics Data System (ADS)

Insects in flight have been studied with optical non destructive techniques with the purpose of using meaningful results in aerodynamics. With the availability of high resolution and large dynamic range CCD sensors the so called interferometric digital holographic technique was used to measure the surface displacement of in flight insect wings, such as butterflies. The wings were illuminated with a continuous wave Verdi laser at 532 nm, and observed with a CCD Pixelfly camera that acquire images at a rate of 11.5 frames per second at a resolution of 1392×1024 pixels and 12 Bit dynamic range. At this frame rate digital holograms of the wings were captured and processed in the usual manner, namely, each individual hologram is Fourier processed in order to find the amplitude and phase corresponding to the digital hologram. The wings displacement is obtained when subtraction between two digital holograms is performed for two different wings position, a feature applied to all consecutive frames recorded. The result of subtracting is seen as a wrapped phase fringe pattern directly related to the wing displacement. The experimental data for different butterfly flying conditions and exposure times are shown as wire mesh plots in a movie of the wings displacement.

Aguayo, Daniel D.; Santoyo, Fernando Mendoza; de La Torre I., Manuel H.; Mendez, Cristian I. Caloca

2008-04-01

208

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

NASA Technical Reports Server (NTRS)

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.

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

2004-01-01

209

Large area, 38 nm half-pitch grating fabrication by using atomic spacer lithography from aluminum wire grids.  

PubMed

We wrapped 150 nm period aluminum wire grid polarizer (WGP) with AlSiOx by using atomic layer deposition at 250 degrees C. The nanometer precision coating defined the spacer to double the spatial frequency of the 100 mm diameter grating fabricated by using a legacy immersion holography setup at 351 nm wavelength. Half-pitch grating of approximately 38 nm was demonstrated with good pattern uniformity, excellent repeatability, and a wide processing window. We believe 10 nm half-pitch grating over even larger areas are viable, overcoming one major hurdle to commercialize nanoimprint. PMID:17163695

Liu, Xiaoming; Deng, Xuegong; Sciortino, Paul; Buonanno, Mike; Walters, Frank; Varghese, Ron; Bacon, Joel; Chen, Lei; O'Brien, Nada; Wang, Jian Jim

2006-12-01

210

Large Contributions of Negative-Energy States to Forbidden Magnetic-Dipole Transition Amplitudes in Alkali-Metal Atoms  

NASA Astrophysics Data System (ADS)

The influence of negative-energy states (NES) on forbidden magnetic-dipole ns1/2-\\(n+1\\)s1/2 transitions in alkali-metal atoms is investigated. We find that the NES contributions are significant in almost all cases and, for rubidium, reduce the transition rate by a factor of 8. We tabulate magnetic-dipole \\(M1\\) transition amplitudes for the alkalis. Our M1 value for cesium, where accurate measurements are available, differs from experiment by 16%. We briefly discuss the feasibility of an experimental test of NES effects.

Savukov, I. M.; Derevianko, A.; Berry, H. G.; Johnson, W. R.

1999-10-01

211

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

PubMed

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(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. PMID:24593356

Fujii, K; Atsumi, S; Watanabe, S; Shikama, T; Goto, M; Morita, S; Hasuo, M

2014-02-01

212

Sub-Picosecond Dynamics of Displacement Cascades  

NASA Astrophysics Data System (ADS)

Sub-picosecond x-ray pulses produced by the Linac Coherent Light Source (LCLS) now enable real time experimental measurements of atomic displacement cascade structure and dynamics on sub-picosecond time scales. Such measurements will make possible the first direct experimental test of molecular dynamics (MD) displacement cascade simulations. Here we will discuss the potential to use single, seeded, 100-fs LCLS hard x-ray pulses focused to ˜100 nm diameter by diamond-based Fresnel zone plate optics to make real-time diffuse scattering measurements on 50 keV Ar-ion-induced cascades in thin single-crystal samples. We will present x-ray Bragg diffuse scattering calculations based on ˜ 4M atom, 25 keV primary knock-on energy MD cascade simulations demonstrating that temporally-random, 100 fs LCLS x-ray pulse measurements of diffuse scattering near low index Bragg reflections can be time-ordered from sub-picoseconds to a few picoseconds. Time ordering is made possible in this regime by the distinct nature of diffuse scattering profiles as a function of time that are produced by shock-induced pressure waves according to MD cascade simulations in Fe. The expected results and the experimental challenges anticipated to perform such measurements will be discussed.

Larson, Bennett; Tischler, Jon; Stoller, Roger; Osetskiy, Yuri; David, Christian

2012-02-01

213

Displacement based multilevel structural optimization  

NASA Technical Reports Server (NTRS)

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.

Striz, Alfred G.

1995-01-01

214

Channelling measurements of the trapping of Al interstitial atoms by Ge atoms in an Al0.1% Ge crystal  

Microsoft Academic Search

It was shown by channelling-backscattering measurements that Ge atoms were displaced from lattice sites during 70-90K He+ irradiation of Al-0.1 at.%Ge crystals. This displacement was about 1.1 AA in (100) directions, and was due to the trapping of self-interstitial Al atoms by Ge atoms, predominantly in the mixed dumbbell configuration. The displaced Ge atoms returned to normal lattice sites during

M. L. Swanson; L. M. Howe; A. F. Quenneville; P. Offermann; K. H. Ecker

1980-01-01

215

Borehole optical lateral displacement sensor  

DOEpatents

There is provided by this invention an optical displacement sensor that utilizes a reflective target connected to a surface to be monitored to reflect light from a light source such that the reflected light is received by a photoelectric transducer. The electric signal from the photoelectric transducer is then imputed into electronic circuitry to generate an electronic image of the target. The target`s image is monitored to determine the quantity and direction of any lateral displacement in the target`s image which represents lateral displacement in the surface being monitored. 4 figs.

Lewis, R.E.

1998-10-20

216

Modified Newmark model for seismic displacements of compliant slopes  

SciTech Connect

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 the dynamic response, including the effects of permanent displacements, of the material above the failure surface is presented. The modified Newmark analysis shows that the decoupled approach produces somewhat conservative estimates of permanent displacements for stiff and/or shallow failure masses, but that it may produce unconservative estimates for failure masses that are soft and/or deep. Many slopes of large, lined landfills may fall into this latter category. The notion of a slope spectrum, which illustrates the effect of the natural period of a potential failure mass on permanent slope displacement, is also introduced.

Kramer, S.L. [Univ. of Washington, Seattle, WA (United States). Dept. of Civil Engineering; Smith, M.W. [GeoEngineers, Inc., Redmond, WA (United States)

1997-07-01

217

Using CIDS with Displaced Workers.  

ERIC Educational Resources Information Center

Discusses the use of the Virginia Vital Information for Education and Work program at J. Sargeant Reynolds Community College, with particular emphasis on career planning and placement services and outreach efforts. Highlights special displaced workers programs with industry. (DMM)

Amburgey, Lillian; Sanborn, Carleton H.

1987-01-01

218

Polyimidazoles Via Aromatic Nucleophilic Displacement  

NASA Technical Reports Server (NTRS)

Experiments show variety of polyimidazoles prepared by aromatic nucleophilic displacement, from reactions of bisphenol imidazoles with activated difluoro compounds. Polyimidazoles have good mechanical properties making them suitable for use as films, moldings, and adhesives.

Connell, John W.; Hergenrother, Paul M.

1990-01-01

219

Clavicle fracture with intrathoracic displacement.  

PubMed

Clavicle fractures are common, and most are isolated injuries. Injury to the nearby subclavian vessels and brachial plexus have classically been described as potential complications of clavicle fractures. However, in the setting of a substantially displaced clavicle fracture, concomitant thoracic trauma is relatively frequent. Injury to the thorax can be difficult to identify on physical examination, and advanced imaging modalities may be required for diagnosis. The evaluation, workup, and management of a patient with intrathoracic displacement of a clavicle fracture are described. Despite the significant fracture displacement and associated pneumothorax, the injury severity was not clinically obvious. Imaging, including a screening chest radiograph and subsequent axial computed tomography, played an important role in diagnosis and management. The patient underwent successful open reduction and plate fixation. A thoracostomy tube was not required at any point during the hospitalization. The patient recovered uneventfully and returned to full work duty by 3 months postoperatively. Including the current report, only 3 cases of intrathoracic displacement of the clavicle have been published in the English literature. All involved fractures of the middle third of the clavicle. The severity of displacement was not obvious in any patient, and diagnosis was dependent on additional imaging. Given the frequency of associated chest trauma and limitations of physical examination, chest radiography should be considered in the evaluation of patients with substantially displaced clavicle fractures. PMID:23937761

Lohse, Grant R; Lee, Donald H

2013-08-01

220

Reactions of large water cluster anions with hydrogen chloride: formation of atomic hydrogen and phase separation in the gas phase.  

PubMed

The reactions of water cluster anions (H2O)n-, n = 30-70, with hydrogen chloride have been studied by Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry. The first HCl taken up by the clusters is presumably ionically dissolved. The solvated electron recombines with the proton, which is thereby reduced to atomic hydrogen and evaporates from the cluster. This process is accompanied by blackbody radiation and collision induced loss of water molecules. Subsequent collisions lead to uptake of HCl and loss of H2O, yielding mixed clusters Cl-(HCl)m(H2O)n until they are saturated with HCl. Those saturated clusters lose H2O and HCl in a characteristic sequence. The final stage of the reaction, involving clusters with m = 0-4 and n = 0-6, is studied in detail with density functional theory calculations. The Cl-(HCl)4(H2O)6 cluster represents an example for supramolecular self-organization in the gas phase: it consists of a tetrahedral Cl-(HCl)4, connected on one side of the tetrahedron to a compact water hexamer. PMID:17315996

Siu, Chi-Kit; Balaj, O Petru; Bondybey, Vladimir E; Beyer, Martin K

2007-03-21

221

THE EFFECTS OF GRAIN BOUNDARIES ON RADIATION DAMAGE PRODUCTION BY DISPLACEMENT CASCADES IN αFe  

Microsoft Academic Search

It is well known that grain boundaries in metals can be sinks for migrating defects such as mobile interstitial atoms, but less is known about the effects of grain boundaries on defect production and defect-grain boundary interactions due to displacement cascades in the vicinity of grain boundaries. Molecular dynamics simulations were performed for displacement cascades in the vicinity of both

Howard L. Heinisch; Richard J. Kurtz; Fei Gao

2011-01-01

222

Nucleation, kinetics and morphology of displacive phase transformations in iron  

NASA Astrophysics Data System (ADS)

An extensive, systematic molecular dynamics (MD) study is performed for analysing the nucleation, kinetics and morphology characteristics of thermally-induced, displacive phase transformations from face-centred cubic (fcc) to body-centred cubic (bcc) iron. At the atomic level these transformation characteristics are influenced by a number of factors, including (i) the appearance of free surfaces, (ii) the initial presence of fcc-bcc grain boundaries, (iii) the existence of point defects (i.e., atomic vacancies) near a grain boundary, (iv) the initial thermal velocities of the atoms, and (v) the specific interatomic potential used. Other MD studies that capture the overall transformation behaviour of iron well have often underestimated or ignored the influence by these factors on the transformation response, with the risk of putting the accuracy, generality and physical explanation of the MD results on loose grounds. The present research illustrates the relative contribution of each of the above factors by means of a detailed comparison study for three different interatomic potentials. The accuracy of the interatomic potentials is established by validating for the fcc and bcc phases the calculated elastic moduli, cohesive energy, vacancy formation energy and interfacial energy against experimental and ab initio data reported in the literature. The importance of calibrating material data of both the stable bcc phase and the metastable fcc phase - instead of the stable bcc phase only - is demonstrated. The numerical results call for general caution when interpreting phenomena that start close to instability points and therefore are sensitive to small disturbances; a large spread in the overall transformation time is found under different initial thermal velocities, interfacial lattice incoherence, boundary conditions (free vs. periodic), and interatomic potentials, where for completely transformed atomic systems the discrepancy between the maximum and minimum transformation time appears to be more than a factor of 150. The transformation time is phenomenologically related to the overall activation energy and the cohesive energy difference of the fcc and bcc phases, which, beyond a certain combination of values, may even prevent the transformation process from occurring. Also, the morphology of the bcc product phase is remarkably sensitive to the type of boundary conditions and the choice of interatomic potential, while the influence by both the set of initial thermal velocities and the interfacial lattice incoherence only becomes apparent for specific atomic samples that transform relatively slowly. The presence of fcc-bcc grain boundaries increases the spatial heterogeneity of transformation events, with the appearance of an increasing number of vacancies at the grain boundary giving rise to a larger overall transformation time. The 10 main results following from the present MD study are conveniently summarised at the end of this communication.

Suiker, A. S. J.; Thijsse, B. J.

2013-11-01

223

Displacement currents in geoelectromagnetic problems  

NASA Astrophysics Data System (ADS)

The influence of displacement currents in conventional geoelectromagnetic (GEM) methods using unimodal transversal electric (TE) or multimodal TE and TM (transversal magnetic) fields is only significant at very high frequencies in the frequency domain or at extremely early times in the time domain. The transient process in the latter includes three stages: the propagation through air, the propagation through earth and the diffusion within the earth. The influence of displacement currents is significant mainly during the former two stages, normally up to several tens to a few hundreds of nanoseconds. The behavior is essentially different in novel GEM methods using a vertical electric dipole (VED) or circular electric dipole (CED) sources of unimodal TM-fields. Under certain geoelectric conditions, the influence of displacement currents in these methods might be crucial at late times as well. This happens, if the model consists of insulating layers. In the absence of displacement currents, such layers would totally mask underlying structures. However, TM-fields including displacement currents depend on geoelectric parameters below insulating layers at late times.

Mogilatov, Vladimir; Goldman, Mark; Persova, Marina; Soloveichik, Yury

2014-06-01

224

A reference material for dynamic displacement calibration  

NASA Astrophysics Data System (ADS)

Calibration of displacement and strain measurement systems is an essential step in providing traceability and confidence in stress and strain distributions obtained from experiment and used to validate simulations employed in engineering design. Reference materials provide a simple, well-defined distribution of the measured quantity that can be traced to an international standard and can be used to assess the uncertainty associated with the measurement system. Previous work has established a reference material and procedure for calibrating optical systems for measuring static, in-plane strain distributions and also demonstrated its use. A new effort is in progress to extend this work to the measurement of three-dimensional displacement distributions induced by cyclic and dynamic loading, including transients and large-scale deformation. The first step in this effort has been to define both the essential and desirable attributes of a reference material for calibrating systems capable of measurements of dynamic displacement and strain. An international consortium of research laboratories, system designers, manufacturers and end-users has identified a list of attributes and members of the experimental mechanics community have been asked to weight the importance of these attributes. The attributes are being utilised to evaluate candidate designs for the reference material which have been generated through a series of brain-storming sessions within the consortium.

Davighi, A.; Hack, E.; Patterson, E.; Whelan, M.

2010-06-01

225

Dual pressure displacement control system  

SciTech Connect

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.

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

1988-02-02

226

Displacer Effects on Pre-adsorbed Polystyrenes In Nanoporous Silica  

NASA Astrophysics Data System (ADS)

The addition of low molecular weight displacers has been used to probe the nature of adsorbed polymer chains on surfaces, and we have employed the displacers to understand the adsorption of polystyrene (PS) onto nanopores of silica particles in cyclohexane. When the radius of gyration (Rg) of PS is smaller than the pore radius (Rp) of the nanoporous silica, the displacement behavior of PS on nanopore surfaces is in quantitative agreement with that of PS on flat surfaces. However, when Rg of PS is larger than Rp of nanopores, the addition of displacers after preadsorbing PS in nanopores has increased the surface access of PS by a factor as large as 100% -200%, depending on the relative size ratio of Rg/Rp. On the contrary, when the displacers are mixed with cylcohexane prior to the PS adsorption in small nanopores, the surface access of PS is monotonically dependent of the composition of displacers. This suggests that the larger PS chains adsorbed in smaller pores are kinetically entrapped with severely limited mobility, and the addition of displacers will facilitate the diffusion of PS in nanopores by inducing a weaker surface binding and swelling of the congested PS chains in nanopores.

Ryu, Chang Y.; Kim, Chansu; Batson, Joel; Kumar, Sanat

2007-03-01

227

Generation of displaced squeezed superpositions of coherent states  

SciTech Connect

We study the method of generation of states that approximate superpositions of large-amplitude coherent states (SCSs) with high fidelity in free-traveling fields. Our approach is based on the representation of an arbitrary single-mode pure state, and SCSs in particular, in terms of displaced number states with an arbitrary displacement amplitude. The proposed optical scheme is based on alternation of photon additions and displacement operators (in the general case, N photon additions and N - 1 displacements are required) with a seed coherent state to generate both even and odd displaced squeezed SCSs regardless of the parity of the used photon additions. It is shown that the optical scheme studied is sensitive to the seed coherent state if the other parameters are unchanged. Output states can approximate either even squeezed SCS or odd SCS shifted relative to each other by some value. This allows constructing a local rotation operator, in particular, the Hadamard gate, which is a mainframe element for quantum computation with coherent states. We also show that three-photon additions with two intermediate displacement operators are sufficient to generate even displaced squeezed SCS with the amplitude 1.7 and fidelity more than 0.99. The effects deteriorating the quality of output states are considered.

Podoshvedov, S. A., E-mail: sapo66@mail.ru [South Ural State University, Department of General and Theoretical Physics (Russian Federation)

2012-03-15

228

EMatch: an efficient method for aligning atomic resolution subunits into intermediate-resolution cryo-EM maps of large macromolecular assemblies  

PubMed Central

Structural analysis of biological machines is essential for inferring their function and mechanism. Nevertheless, owing to their large size and instability, deciphering the atomic structure of macromolecular assemblies is still considered as a challenging task that cannot keep up with the rapid advances in the protein-identification process. In contrast, structural data at lower resolution is becoming more and more available owing to recent advances in cryo-electron microscopy (cryo-EM) techniques. Once a cryo-EM map is acquired, one of the basic questions asked is what are the folds of the components in the assembly and what is their configuration. Here, a novel knowledge-based computational method, named EMatch, towards tackling this task for cryo-EM maps at 6–10?Å resolution is presented. The method recognizes and locates possible atomic resolution structural homologues of protein domains in the assembly. The strengths of EMatch are demonstrated on a cryo-EM map of native GroEL at 6?Å resolution.

Dror, Oranit; Lasker, Keren; Nussinov, Ruth; Wolfson, Haim

2007-01-01

229

DISPLACEMENT CASCADE SIMULATION IN TUNGSTEN AT 1025 K  

SciTech Connect

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.

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

2013-09-30

230

Retraining Displaced Workers. Policy Brief  

ERIC Educational Resources Information Center

Robert LaLonde of the University of Chicago and Daniel Sullivan of the Federal Reserve Bank of Chicago suggest that retraining through our nation's community colleges is a way to reduce the skills gaps of at least some of these displaced workers and increase their reemployment earnings. Although workers may still experience significant earnings…

LaLonde, Robert; Sullivan, Daniel

2010-01-01

231

DISPLACEMENT BASED SEISMIC DESIGN METHODS.  

SciTech Connect

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.

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

2003-07-15

232

Silicon threshold displacement energy determined by photoluminescence in electron-irradiated cubic silicon carbide  

SciTech Connect

In view of the potential use of silicon carbide (SiC) in the nuclear industry, it is of major interest to understand point defect formation in this material. This work is a contribution to the determination of the silicon threshold displacement energy in the cubic polytype of SiC using electron irradiations with increasing energies from 275 to 680 keV. The photoluminescence signal of the silicon vacancy was related to the number of displacements per atom in the silicon sublattice. This quantity was calculated taking into account the energy loss and angular dispersion of electrons in the target. A best fit of experimental data was obtained for a displacement cross section using a threshold displacement energy of 25 eV along the [100] lattice direction. We checked the relevance of this result by comparing the experimental concentration of silicon single vacancies measured by electron paramagnetic resonance spectroscopy with the theoretical number of displaced silicon atoms.

Lefevre, Jeremie; Esnouf, Stephane; Petite, Guillaume [Laboratoire des Solides Irradies, CEA-IRAMIS, CNRS, Ecole Polytechnique, F-91128 Palaiseau Cedex (France); Costantini, Jean-Marc [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette Cedex (France)

2009-01-15

233

Interaction of displacement cascade with helium bubbles in alpha-iron: Computer simulation  

SciTech Connect

Molecular dynamics (MD) method has been performed to study the interaction of displacement cascade with He bubbles with two sets of potentials. The results show that the stability of He bubbles depends much on the initial He-vacancy (He/V) ratio and the recoil energy. For an initial He/V ratio of 3, the cascade leads to the increase in the number of vacancies in the He bubble and the decrease in the He/V ratio. For an initial He/V ratio of 0.5, the interaction of a cascade with the He/V bubble results in the decrease in the number of vacancies and the increase in the He/V ratio. For an initial He/V ratio of 1, the stability of the bubbles slightly depends on the primary knock-on atom (PKA) energy. Furthermore, a large number of self-interstitial atom clusters are formed after cascade collision for the He/V ratio of 3, while large vacancy clusters are observed for the He/V ratio of 0.5. However, some differences of defect production and clustering between the two sets of potentials are observed, which may be associated the formation energies of He-V clusters, the binding energies of vacancies and He atoms to the clusters and the probability of subcascade formation.

Pu, Jin; Yang, Li; Gao, Fei; Heinisch, Howard L.; Kurtz, Richard J.; Zu, Xiaotao T.

2008-09-01

234

Electrodynamic Displacement of Atomic Energy Levels. II. Lamb Shift  

Microsoft Academic Search

The vacuum fluctuations of the photon and pair fields modify the interaction of an electron with an electromagnetic field. The effects on the energy levels are conveniently described in terms of the mass operator and the vacuum polarization potential. An operator calculus for handling the mass operator is used to separate the contribution of low energy quanta, for which the

Robert Karplus; Abraham Klein; Julian Schwinger

1952-01-01

235

Electrodynamic Displacement of Atomic Energy Levels. I. Hyperfine Structure  

Microsoft Academic Search

The vacuum fluctuations of the photon and pair fields modify the interaction of an electron with an electromagnetic field. The effects on the energy levels are conveniently described in terms of the mass operator and the vacuum polarization potential. A gauge-covariant expansion of the mass operator for the motion of an electron in a weak external electromagnetic field is derived;

Robert Karplus; Abraham Klein

1952-01-01

236

Free displacer and Ringbom displacer for a Malone refrigerator  

SciTech Connect

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.

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

1994-05-01

237

Contribution of nuclear displacements to the static polarizability of molecules in an external electric field: Application to fluorinated fullerenes C{sub 60}F{sub n}  

SciTech Connect

In molecules with ionic contributions to the binding, the contribution of nuclear displacements (due to the external field) to the static polarizability can be decisive. Using the finite field method, we optimized the structure with and without a finite external electric field by a total energy minimization and we calculated the polarizability from the induced dipole moment. In C{sub 60}F{sub n}, fluorination mostly increases the polarizability. Only for n=2 and 18, where the molecule without an external field has a very large dipole moment, does fluorination decrease it. For large n (n=20, 36, and 48), the polarizability per added F atom due to nuclear displacements is increased by a factor of about 2. The validity of the additivity model has been discussed.

Zagorodniy, K.; Taut, M.; Hermann, H. [Leibniz Institute for Solid State and Materials Research, IFW Dresden, P.O. Box 270016, 01171 Dresden (Germany)

2006-05-15

238

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents during alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

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

1991-01-01

239

Polyphenylquinoxalines via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polyphenylquinoxalines are prepared by the nucleophilic displacement reaction of di(hydroxyphenyl)quinoxaline monomers with activated aromatic dihalides or dinitro compounds. The reactions are carried out in polar aprotic solvents using alkali metal bases at elevated temperatures under nitrogen. The di(hydroxyphenyl)quinoxaline monomers are prepared either by reacting stoichiometric quantities of aromatic bis(o-diamines) with a hydroxybenzil or by reacting o-phenylenediamine with a dihydroxybenzil or bis(hydroxyphenylglyoxylyl)benzene.

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

1990-01-01

240

Polybenzimidazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

241

PHON: A program to calculate phonons using the small displacement method  

NASA Astrophysics Data System (ADS)

The program PHON calculates force constant matrices and phonon frequencies in crystals. From the frequencies it also calculates various thermodynamic quantities, like the Helmholtz free energy, the entropy, the specific heat and the internal energy of the harmonic crystal. The procedure is based on the small displacement method, and can be used in combination with any program capable to calculate forces on the atoms of the crystal. In order to examine the usability of the method, I present here two examples: metallic Al and insulating MgO. The phonons of these two materials are calculated using density functional theory. The small displacement method results are compared with those obtained using the linear response method. In the case of Al the method provides accurate phonon frequencies everywhere in the Brillouin Zone (BZ). In the case of MgO the longitudinal branch of the optical phonons near the centre of the BZ is incorrectly described as degenerate with the two transverse branches, because the non-analytical part of the dynamical matrix is ignored here; however, thermodynamic properties like the Helmholtz free are essentially unaffected. Program summaryProgram title: PHON Catalogue identifier: AEDP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 19 580 No. of bytes in distributed program, including test data, etc.: 612 193 Distribution format: tar.gz Programming language: Fortran 90 Computer: Any Unix, Linux Operating system: Unix RAM: Depends on super-cell size, but usually negligible Classification: 7.8 External routines: Subprograms ZHEEV and DSYEV (Lapack); needs BLAS. A tutorial is provided with the distribution which requires the installation of the quantum-espresso package ( http://www.quantum-espresso.org) Nature of problem: Stable crystals at low temperature can be well described by expanding the potential energy around the atomic equilibrium positions. The movements of the atoms around their equilibrium positions can then be described using harmonic theory, and is characterised by global vibrations called phonons, which can be identified by vectors in the Brillouin zone of the crystal, and there are 3 phonon branches for each atom in the primitive cell. The problem is to calculate the frequencies of these phonons for any arbitrary choice of q-vector in the Brillouin zone. Solution method: The small displacement method: each atom in the primitive cell is displaced by a small amount, and the forces induced on all the other atoms in the crystal are calculated and used to construct the force constant matrix. Supercells of ˜100 atoms are usually large enough to describe the force constant matrix up to the range where its elements have fallen to negligibly small values. The force constant matrix is then used to compute the dynamical matrix at any chosen q-vector in the Brillouin zone, and the diagonalisation of the dynamical matrix provides the squares of the phonon frequencies. The PHON code needs external programs to calculate these forces, and it can be used with any program capable of calculating forces in crystals. The most useful applications are obtained with codes based on density functional theory, but there is no restriction on what can be used. Running time: Negligible, typically a few seconds (or at most a few minutes) on a PC. It can take longer if very dense meshes of q-points are needed, for example, to compute very accurate phonon density of states.

Alfè, Dario

2009-12-01

242

Measurement of Cantilever Displacement Using a Compact Disk/Digital Versatile Disk Pickup Head  

NASA Astrophysics Data System (ADS)

We use the optical pickup head of a commercial compact disk (CD)/digital versatile disk (DVD) read only memory (ROM) drive to detect the vertical displacement of micro fabricated cantilever in atomic force microscopy (AFM). Both the contact and AC modes of AFM are demonstrated. The single atomic steps of graphite can be resolved, indicating that atomic resolution in the vertical displacement detection can be achieved with this new setup. The low cost, compact size, and the light weight of CD/DVD optical pickups may offer new advantages in future AFM designs.

Hwu, En?Te; Huang, Kuang?Yuh; Hung, Shao?Kang; Hwang, Ing?Shouh

2006-03-01

243

A wireless laser displacement sensor node for structural health monitoring.  

PubMed

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

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

2013-01-01

244

A Wireless Laser Displacement Sensor Node for Structural Health Monitoring  

PubMed Central

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.

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

2013-01-01

245

Dynamic displacement measurement of bridges using vision-based system  

NASA Astrophysics Data System (ADS)

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.

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

2006-04-01

246

Effect of coupling displacement on thermal current of Frenkel-Kontorova lattices  

NASA Astrophysics Data System (ADS)

Effect of coupling displacement on thermal current of Frenkel-Kontorova (FK) lattices in the underdamped case is investigated by means of numerical calculations. The results indicate that: (i) as the system has less atoms and is symmetric, the coupling displacement can boost up its thermal current, and absolute value of the thermal current as a function of the coupling displacement exhibits one or two peaks, determined by period of the FK lattices. (ii) As the system with less atoms is asymmetric, the coupling displacement affects its thermal current only in the case of either negative temperature difference or positive temperature difference, depending on asymmetry of the on-site potentials of the FK lattices. The coupling displacement cannot only enhance negative differential thermal resistance effect but also regulate thermal rectifier of the system as a thermal switch. (iii) Along with an increasing atomic number of the FK lattices, the effect of the coupling displacement on the system gradually disappears. Our results have the implication that the coupling displacement between nonlinear lattices plays a crucial role in the design of thermal devices.

Zhang, Jianqiang; Chen, Xiuhua; Chen, Ruyin; Nie, Linru; Zheng, Zhigang

2014-06-01

247

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2013 CFR

...ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Motorcycles § 205.153 Engine displacement. (a) Engine displacement must be calculated using nominal engine values and...

2013-07-01

248

Fixture for Linearly Variable Displacement Transducers  

NASA Technical Reports Server (NTRS)

Original point of interest on shear panel tracked throughout loading. Technique and fixture measure out-of-plane displacements on shear panel using linearly variable displacement transducers (LVDT's) while tracking original panel location. Technique adaptable to any size shear panel.

Farley, G. L.; Baker, D. J.

1985-01-01

249

Meridional displacement of the Antarctic Circumpolar Current.  

PubMed

Observed long-term warming trends in the Southern Ocean have been interpreted as a sign of increased poleward eddy heat transport or of a poleward displacement of the entire Antarctic Circumpolar Current (ACC) frontal system. The two-decade-long record from satellite altimetry is an important source of information for evaluating the mechanisms governing these trends. While several recent studies have used sea surface height contours to index ACC frontal displacements, here altimeter data are instead used to track the latitude of mean ACC transport. Altimetric height contours indicate a poleward trend, regardless of whether they are associated with ACC fronts. The zonally averaged transport latitude index shows no long-term trend, implying that ACC meridional shifts determined from sea surface height might be associated with large-scale changes in sea surface height more than with localized shifts in frontal positions. The transport latitude index is weakly sensitive to the Southern Annular Mode, but is uncorrelated with El Niño/Southern Oscillation. PMID:24891396

Gille, Sarah T

2014-07-13

250

High-accuracy displacement interferometry in air  

NASA Astrophysics Data System (ADS)

The absolute accuracy of laser interferometers employed in displacement metrology is limited by two dominant factors: uncertainties in the source vacuum wavelength and the refractive index of the ambient air. In this paper we describe an interferometer system designed to minimize these uncertainties. Based on a commercial interferometer, the new system features direct measurement of the vacuum wavelength by frequency comparison with a portable iodine-stabilized He-Ne laser. The refractive index of air is computed from accurately measured values of pressure, temperature, and relative humidity. Combined with a desktop computer, the interferometer system permits the automated field measurement of displacement errors (such as those associated with precision machine tools) with an absolute accuracy of 8.5 parts in 10^8. Performance of the interferometer in field metrology is illustrated by the results of recent validation testing of the large optics diamond turning machine (LODTM) at Lawrence Livermore National Laboratory. These results highlight the need for new measurements of the absolute refractive index of standard air in order to reduce a limiting uncertainty on such measurements of +-5 parts in 10^8.

Estler, W. Tyler

1985-03-01

251

Method for quantitative determination and separation of trace amounts of chemical elements in the presence of large quantities of other elements having the same atomic mass  

DOEpatents

Photoionization via autoionizing atomic levels combined with conventional mass spectroscopy provides a technique for quantitative analysis of trace quantities of chemical elements in the presence of much larger amounts of other elements with substantially the same atomic mass. Ytterbium samples smaller than 10 ng have been detected using an ArF* excimer laser which provides the atomic ions for a time-of-flight mass spectrometer. Elemental selectivity of greater than 5:1 with respect to lutetium impurity has been obtained. Autoionization via a single photon process permits greater photon utilization efficiency because of its greater absorption cross section than bound-free transitions, while maintaining sufficient spectroscopic structure to allow significant photoionization selectivity between different atomic species. Separation of atomic species from others of substantially the same atomic mass is also described.

Miller, C.M.; Nogar, N.S.

1982-09-02

252

Displacement Compensation of Temperature Probe Data  

NASA Technical Reports Server (NTRS)

Analysis of temperature data from a probe in a vertical Bridgman furnace growing germanium crystals revealed a displacement of the temperature profile due to conduction error. A theoretical analysis shows that the displacement compensation is independent of local temperature gradient. A displacement compensation value should become a standard characteristic of temperature probes used for temperature profile measurements.

Welch, Christopher S.; Hubert, James A.; Barber, Patrick G.

1996-01-01

253

The everyday violence of forced displacement : community, memory and identity politics among Kurdish internal forced migrants in Turkey  

Microsoft Academic Search

Kurds in Turkey: the everyday violence of their forced displacement. Roughly fifteen years ago, more than one million Kurds were forcibly displaced from their villages in Southeast Turkey, mostly by Turkish security troops, who were engaged in a violent struggle with the PKK, an armed organization that strives for Kurdish self-rule. Large numbers of displaced Kurds migrated to cities in

M. T. Geerse

2011-01-01

254

Wireless Power Transfer during Displacement Using Electromagnetic Coupling in Resonance  

Microsoft Academic Search

This paper proposes a novel way for achieving wireless power transfer from a transmitting antenna to a receiving antenna. This technique is suitable for charging electric vehicles (EVs) because the proposed antennas can transfer power wirelessly with high efficiencies when the antennas are displaced and have large air gaps. This technique utilizes near-field antennas at resonance; however, this technique is

Takehiro Imura; Hiroyuki Okabe; Toshiyuki Uchida; Yoichi Hori

2010-01-01

255

Multiple displacement amplification improves PGD for fragile X syndrome  

Microsoft Academic Search

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

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

2006-01-01

256

Plasma atomic layer etching  

Microsoft Academic Search

Summary form only given. The thinning of the dielectric in the metal (and non-metal) gate stacks and the need to resolve etching on an atomic layer basis present large technological challenges. Conventional plasma processes which utilize reactive ion etching typically do not have sufficient controllability to achieve atomic layer resolution and to avoid damage. To ensure atomic-level control it is

A. Agarwal; M. J. Kushner

2006-01-01

257

Anharmonic thermal motion of atoms in thermoelectric Mg2Si studied via convergent-beam electron diffraction  

NASA Astrophysics Data System (ADS)

We study the thermal motion of the atoms in the thermoelectric material Mg2Si by using electron diffraction. The nanodiffraction or convergent-beam electron diffraction technique we use allows us to observe simultaneously many Bragg reflections with large reciprocal lattice vectors. Previous observations of anharmonicity by single-crystal x-ray diffraction are confirmed, and we determine the anharmonicity parameter of the Mg atom in the tetrahedral environment with high accuracy, ?=(-4.27±0.14)×10-12 erg Å-3 around room temperature. In an alternative picture the Mg atom tends to vibrate around positions displaced 4.50±0.14 pm from the center of the tetrahedron.

Valset, K.; Taftø, J.; Wu, L.; Zhu, Y.

2011-12-01

258

Interferometric fiber optic displacement sensor  

DOEpatents

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.

Farah, J.

1999-04-06

259

Interferometric fiber optic displacement sensor  

SciTech Connect

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.

Farah, J.

1995-05-30

260

Interferometric fiber optic displacement sensor  

DOEpatents

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.

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

1999-01-01

261

Interferometric fiber optic displacement sensor  

DOEpatents

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.

Farah, John (M.I.T. Branch P.O. Box 301, Cambridge, MA 02139)

1995-01-01

262

Heavy neutrino searches at the LHC with displaced vertices  

NASA Astrophysics Data System (ADS)

Sterile neutrinos with masses in the range of 1-100 GeV have been searched for in a variety of experiments. Here, we discuss the prospects of searching for sterile neutrinos at the LHC using displaced vertices. Two different cases are discussed: (i) the standard model extended with sterile neutrinos, and (ii) right-handed neutrinos in a left-right symmetric extension of the standard model. A dedicated displaced vertex search will allow us to probe parts of the parameter space not accessible to other searches, but both cases will require a large luminosity.

Helo, J. C.; Kovalenko, S. G.; Hirsch, M.

2014-04-01

263

A Molecular dynamics study of helium bubble stability during high-energy displacement cascades in ?-iron  

SciTech Connect

The interactions of high-energy displacement cascades with helium bubbles in ?-Fe are investigated using molecular dynamics simulations. Initial bubbles with the volumes of 212 and 636 Å3 are considered, and the helium-to-vacancy (He/V) ratio in the bubbles varies from 0.5 to 3. Primary knock-on atom (PKA) energy, Ep, is up to 40 keV. The results show that the change of nm-sized He bubbles due to displacement cascade does not depend much on the bubble size, but rather on the He/V ratio and the recoil energy. For the initial He/V ratio less than 1, the size of the bubbles decreases with increasing PKA energy, but the He/V ratio increases. However, for the initial He/V ratio of 3, the size of the bubbles increases, and the He/V ratio decreases with PKA energy. For the initial He/V ratio of 1, the ratio of the small bubble decreases slightly, but the ratio of the large bubble remains unchanged for lower PKA energy, and increases slightly for higher PKA energy. The reasons for these observed phenomena have been explained.

Pu, Jin; Yang, Li; Zu, Xiaotao; Gao, Fei

2007-08-01

264

Non-contact displacement estimation using Doppler radar.  

PubMed

Non-contact Doppler radar has been used extensively for detection of physiological motion. Most of the results published to date have been focused on estimation of the physiological rates, such as respiratory rate and heart rate, with CW and modulated waveforms in various settings. Accurate assessment of chest displacement may take this type of monitoring to the new level, by enabling the estimation of associated cardiopulmonary volumes, and possibly pulse pressure. To obtain absolute chest displacement with highest precision, full nonlinear phase demodulation of the quadrature radar outputs must be performed. The accuracy of this type of demodulation is limited by the drifting received RF power, varying dc offset, and channel quadrature imbalance. In this paper we demonstrate that if relatively large motion is used to calibrate the system, smaller motion displacement may be acquired with the accuracy on the order of 30 µm. PMID:23366212

Gao, Xiaomeng; Singh, Aditya; Yavari, Ehsan; Lubecke, Victor; Boric-Lubecke, Olga

2012-01-01

265

Variable delivery, fixed displacement pump  

DOEpatents

A variable delivery, fixed displacement pump comprises a plurality of pistons reciprocated within corresponding cylinders in a cylinder block. The pistons are reciprocated by rotation of a fixed angle swash plate connected to the pistons. The pistons and cylinders cooperate to define a plurality of fluid compression chambers each have a delivery outlet. A vent port is provided from each fluid compression chamber to vent fluid therefrom during at least a portion of the reciprocal stroke of the piston. Each piston and cylinder combination cooperates to close the associated vent port during another portion of the reciprocal stroke so that fluid is then pumped through the associated delivery outlet. The delivery rate of the pump is varied by adjusting the axial position of the swash plate relative to the cylinder block, which varies the duration of the piston stroke during which the vent port is closed.

Sommars, Mark F. (Sparland, IL)

2001-01-01

266

An ion displacement membrame model.  

PubMed

The usual assumption in treating the diffusion of ions in an electric field has been that the movement of each ion is independent of the movement of the others. The resulting equation for diffusion by a succession of spontaneous jumps has been well stated by Parlin and Eyring. This paper will consider one simple case in which a different assumption is reasonable. Diffusion of monovalent positive ions is considered as a series of jumps from one fixed negative site to another. The sites are assumed to be full (electrical neutrality). Interaction occurs by the displacement of one ion by another. An ion leaves a site if and only if another ion, not necessarily of the same species, attempts to occupy the same site. Flux ratios and net fluxes are given as functions of the electrical potential, concentration ratios, and number of sites encountered in crossing the membrane. Quantitative comparisons with observations of Hodgkin and Keynes are presented. PMID:6048876

Hladky, S B; Harris, J D

1967-09-01

267

Displaced electrode process for welding  

SciTech Connect

A method is described for the butt-welding of a relatively heavy mass to a relatively small mass such as a thin-wall tube. In butt-welding heat is normally applied at the joint between the two pieces which are butt-welded together. The application of heat at the joint results in overheating the tube which causes thinning of the tube walls and porosity in the tube material. This is eliminated by displacing the welding electrode away from the seam toward the heavier mass so that heat is applied to the heavy mass and not at the butt seam. Examples of the parameters used in welding fuel rods are given. The cladding and end plugs were made of Zircalloy. The electrode used was of 2 percent thoriated tungsten. (auth)

Heichel, L.J.

1975-08-26

268

Are Surface Displacements Representative of Slip at Seismogenic Depths? Implications for Geologic Slip Rate Studies  

Microsoft Academic Search

It has long been recognized that during large strike-slip earthquakes surface displacements are in many instances smaller than displacements at depth. This is often interpreted to imply that a significant proportion of the slip at depth is accommodated by distributed deformation near the surface. We hypothesize that the degree to which deformation is localized at the surface is fundamentally controlled

B. Haravitch; J. F. Dolan; Y. Klinger

2009-01-01

269

Displaced Children in U.S. History: Stories of Courage and Survival  

ERIC Educational Resources Information Center

This article focuses on the experiences and survival of displaced children in four large migrations in U.S. history. The chaos and despair caused by Hurricane Katrina are reminders that the displacement and survival of children are timely and relevant topics for the social studies curriculum. Hurricane Katrina was the worst natural disaster in…

Betts, Brenda

2006-01-01

270

A tale of three cities: Crime and displacement after Hurricane Katrina  

Microsoft Academic Search

When Hurricane Katrina struck New Orleans in August 2005, it greatly disrupted both the physical and social structures of that community. One consequence of the hurricane was the displacement of large numbers of New Orleans residents to other cities, including Houston, San Antonio, and Phoenix. There has been media speculation that such a grand-scale population displacement led to increased crime

Sean P. Varano; Joseph A. Schafer; Jeffrey M. Cancino; Scott H. Decker; Jack R. Greene

2010-01-01

271

The 2011 Tohoku-Oki earthquake: displacement reaching the trench axis.  

PubMed

We detected and measured coseismic displacement caused by the 11 March 2011 Tohoku-Oki earthquake [moment magnitude (M(W)) 9.0] by using multibeam bathymetric surveys. The difference between bathymetric data acquired before and after the earthquake revealed that the displacement extended out to the axis of the Japan Trench, suggesting that the fault rupture reached the trench axis. The sea floor on the outermost landward area moved about 50 meters horizontally east-southeast and ~10 meters upward. The large horizontal displacement lifted the sea floor by up to 16 meters on the landward slope in addition to the vertical displacement. PMID:22144619

Fujiwara, Toshiya; Kodaira, Shuichi; No, Tetsuo; Kaiho, Yuka; Takahashi, Narumi; Kaneda, Yoshiyuki

2011-12-01

272

New method of evaluation for interatomic interaction potential in LEIS with large-angle scattering using the two-atom scattering model  

NASA Astrophysics Data System (ADS)

The interaction potential between an incident ion and a target atom in impact-collision ion scattering spectroscopy (ICISS), which is a specialization of low energy ion scattering (LEIS) and its variants, i.e. ICISS with detection of neutrals (NICISS), coaxial ICISS (CAICISS) and impact-collision atom scattering spectroscopy with detection of neutrals (NICASS), has been evaluated by the new method using the dependence of the total scattering angle on the impact parameter for the first collision in the numerical calculations based on the two-atom scattering model (TWASM). From the comparison of determined values of scaling factor for the Firsov screening length by three-dimensional computer simulations with calculated ones by TWASM, it became obviously that the interatomic potentials for the various combinations of an incident ion and a target atom in LEIS are suitably given by the Moliere potential with the reduced Firsov screening length employing the scaling factor obtained in TWASM calculations.

Takeuchi, Wataru; Matsuda, Naoki

2008-03-01

273

Parental displacement and adolescent suicidality: exploring the role of failed belonging.  

PubMed

Prior studies have demonstrated that events causing displacement from parents--such as parental death, abandonment of the adolescent, or divorce--represent a risk factor for adolescent suicide, but research to date has not established a theoretical model explaining the association between parental displacement and adolescent suicidal behavior. The current studies examined the construct of failed belonging proposed by the interpersonal theory of suicide as one factor that may link parental displacement with adolescent suicide. Study 1 found that low levels of belonging mediated the association between parental displacement and adolescent suicide attempts in a large, urban community sample of older adolescents between the ages of 18 and 23. In Study 2, parental displacement interacted with low belonging to predict suicide attempts, such that adolescents (average age = 16.6 years; SD = 1.2) who experienced both displacement and low levels of belonging had the highest risk for suicide. PMID:22023272

Timmons, Katherine A; Selby, Edward A; Lewinsohn, Peter M; Joiner, Thomas E

2011-01-01

274

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

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.

Pauling, Linus

1988-01-01

275

Character displacement in the fighting colours of Hetaerina damselflies.  

PubMed

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

Anderson, Christopher N; Grether, Gregory F

2010-12-01

276

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

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

Pauling, Linus

1989-01-01

277

COMPETITIVE DISPLACEMENT AMONG INSECTS AND ARACHNIDS  

Microsoft Academic Search

? Abstract Competitive displacement,is the most severe outcome,of interspecific competition. For the purposes of this review, we define this type of displacement as the removal,of a formerly established species from a habitat as a result of direct or indirect competitive,interactions with another species. We reviewed,the literature for recent putative cases of competitive displacement,among,insects and arachnids and assessed the evidence,for the

Stuart R. Reitz; John T. Trumble

2001-01-01

278

An improved displacement damage monitor LED  

Microsoft Academic Search

A frequency-domain technique for measuring carrier lifetime in GaAs light-emitting-diode (LED) displacement damage monitors capable of high sensitivity and repeatability is developed. Applications of this technique that take advantage of the high sensitivity of this method, including the measurement of the threshold energy for lattice displacement in GaAs, are described. The measured minimum electron energy for displacement damage was 270±15

A. L. Barry; R. Maxseiner; R. Wojcik; M. A. Briere; D. Braeunig

1990-01-01

279

Transverse sacral fractures with anterior displacement  

Microsoft Academic Search

Transverse fractures of the sacrum with anterior displacement are the rarest type of transverse sacral fractures. They usually\\u000a occur at the S1–S2 region in suicide jumpers. A clinical study was performed to evaluate the diagnosis, treatment and outcome\\u000a of transverse sacral fractures with anterior displacement. We present six patients with a transverse fracture of the sacrum\\u000a with anterior displacement. All

George S. Sapkas; Andreas F. Mavrogenis; Panayiotis J. Papagelopoulos

2008-01-01

280

Lateral displacement estimation using tissue incompressibility  

Microsoft Academic Search

Using the incompressibility property of soft tissue, lateral displacements can be reconstructed from axial strain measurements. Results of simulations and experiments on gelatin-based tissue equivalent phantoms are compared with theoretical displacements, as well as estimates derived from traditional speckle tracking. Incompressibility processing greatly improves the accuracy and signal-to-noise ratio (SNR) of lateral displacement measurements compared with more traditional speckle tracking

Mark A. Lubinski; Stanislav Y. Emelianov; K. R. Raghavan; Andrew E. Yagle; Andrei R. Skovoroda; Matthew O'Donnell

1996-01-01

281

Microbial Adhesion in Flow Displacement Systems  

PubMed Central

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.

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

2006-01-01

282

Intrinsic Mean Square Displacement in Proteins  

NASA Astrophysics Data System (ADS)

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.

Vural, Derya; Glyde, Henry R.

2012-02-01

283

Polybenzoxazole via aromatic nucleophilic displacement  

NASA Technical Reports Server (NTRS)

Polybenzoxazoles (PBO) are heterocyclic macromolecules which were first synthesized in a two-step process by the initial formation of aromatic diacid chlorides with bis(o-aminophenol)s through solution condensation of aromatic diacid chlorides with bis(o-aminophenol)s followed by thermal cyclodehydration. Since then several methods were utilized in their synthesis. The most common synthetic method for PBO involves a polycondensation of bis(o-aminophenol)s with aromatic diacid diphenyl esters. Another preparative route involves the solution polycondensation of the hydrochloride salts of bis(o-amino phenol)s with aromatic diacids in polyphosphoric acid. Another synthetic method involves the initial formation of poly(o-hydroxy amide)s from silylated bis(o-aminophenol)s with aromatic diacid chlorides followed by thermal cyclodehydration to PBO. A recent preparative route involves the reaction of aromatic bisphenols with bis(fluorophenyl) benzoxazoles by the displacement reaction to form PBO. The novelty of the present invention is that high molecular weight PBO of new chemical structures are prepared that exhibit a favorable combination of physical and mechanical properties.

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

1993-01-01

284

Tetrahedral atom ordering in sodium feldspars: a Monte Carlo study  

NASA Astrophysics Data System (ADS)

The substitutional disorder of Al and Si atoms in sodium feldspars has been analyzed by Monte Carlo simulations. To study the influence of non-configurational degrees of freedom on the order—disorder process, we performed simulations allowing atom displacements along with interchanges between Al and Si atoms. It is found that the coupling between configurational and displacive degrees of freedom is important to explain the order—disorder properties of this compound from a microscopic point of view.

Gordillo, M. C.; Herrero, C. P.

1995-05-01

285

Effects of Fault Displacement on Emplacement Drifts  

SciTech Connect

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.

F. Duan

2000-04-25

286

Gumdrop Atoms  

NSDL National Science Digital Library

Students use gumdrops and toothpicks to make lithium atom models. Using these models, they investigate the makeup of atoms, including their relative size. Students are then asked to form molecules out of atoms, much in the same way they constructed atoms out of the particles that atoms are made of. Students also practice adding and subtracting electrons from an atom and determining the overall charges on atoms.

Integrated Teaching And Learning Program

287

Displaced femoral neck fractures in the elderly  

Microsoft Academic Search

This study evaluated the relationship of the disposition and outcome of patients with displaced femoral neck fractures with the type of surgical treatment. From 1993 to 1996, 186 patients with displaced femoral neck fractures who were 65 years of age or older were treated at one hospital. One hundred and twenty fractures were treated with reduction and internal fixation; 66

Richard Iorio; William L Healy; David Appleby; John Milligan; Michael Dube

2004-01-01

288

Gas Miscible Displacement Enhanced Oil Recovery.  

National Technical Information Service (NTIS)

The general goal of the Gas Miscible Displacement Project is to support high-risk, long-term CO sub 2 /EOR research that does not duplicate or displace private and other public R and D efforts. More specifically, the project goals are: (1) to understand t...

1984-01-01

289

Horizontal displacements of rock foundations of dams  

SciTech Connect

This paper uses geodetic survey methods to assess the horizontal displacements of dam foundations for several hydroelectric power plants in the Soviet Union. The effects of filling the reservoirs are outlined and the dependence of the degree of displacement on dam height is analyzed. The results are tabulated.

Karlson, A.A.

1987-08-01

290

Investigation of operating parameters in high-performance displacement chromatography.  

PubMed

The effect of operational parameters of displacement chromatography was examined in the separation of various mixtures such as that of the main hydrolysis products of methylfurylbutyrolactone, a potential anticancer drug, the diastereoisomers benzoyl-D- and benzoyl-L-phenylalanyl-L-alanyl-L-proline, as well as polyethylene glycol homologues containing 1-10 ethylene oxide units. The chromatograph was assembled from modules generally used in analytical high-performance liquid chromatography (HPLC) and the column effluent was analyzed by an on-line HPLC unit at 30-sec intervals. Octadecyl-silica was used throughout as the stationary phase. Derivatives of ethylene glycol and propylene glycol as well as tetrabutylammonium bromide and n-butanol were used as displacers. The throughput was used as the measure of efficiency. In the absence of axial dispersion, for a given separation various displacers are expected to yield the same efficiency if the slope of the operating line is kept the same by appropriate adjustment of displacer concentrations. In practice, however, the optimum slope of the operating line has to be determined experimentally as most available chromatographic systems depart from ideal behavior. The dependence of the throughput on the flow-rate and feed load also indicated the presence of non-equilibrium phenomena and the optimum value of these parameters was established experimentally. In most cases water was used as the carrier solvent but the separation of poorly soluble peptides required the use of hydro-organic carriers. Results obtained with octadecyl-silicas of different origin and a given displacer were found to vary significantly suggesting that even for stationary phases of the same type the selection of displacer requires special consideration. Most experiments were carried out with columns having dimensions customary in analytical HPLC. Increasing the inner diameter of the column did not result in the expected increase in throughout probably due to poor distribution of the sample at the column entrance. Therefore scaling-up the process requires careful engineering of inlet conditions. Throughput can be increased by connecting a small inner diameter column to the outlet of a large diameter preparative column. As theoretical predictions for ideal displacement chromatography do not hold in practice when axial dispersion is significant, optimization of the process requires experimental support. The results obtained in the separation of a variety of mixtures shed light on the most important operational aspects of displacement chromatography and suggest approaches to find optimum conditions.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:4044730

Frenz, J; van der Schrieck, P; Horváth, C

1985-08-01

291

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

NASA Technical Reports Server (NTRS)

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.

Soares, Schubert F. (Inventor)

2002-01-01

292

Microwave-accelerated speciation analysis for butyltin compounds in sediments and biomaterials by large volume injection capillary gas chromatography quartz furnace atomic absorption spectrometry  

Microsoft Academic Search

A method for speciation analysis of butyltins in sediments and biomaterials by capillary GC with atomic absorption spectrometric detection was developed. Mono-, di- and tributyltin in sediments were quantitatively leached with 50% acetic acid, whereas biomaterials were dissolved in a 25% tetramethyl ammonium hydroxide (TMAH) solution; both processes were completed under the action of a low-power focused microwave field within

Joanna Szpunar; Michiel Ceulemans; Vincent O. Schmitt; Freddy C. Adams; Ryszard ?obi?ski

1996-01-01

293

Real-time PCR genotyping using displacing probes  

PubMed Central

Simple and reliable genotyping technology is a key to success for high-throughput genetic screening in the post-genome era. Here we have developed a new real-time PCR genotyping approach that uses displacement hybridization-based probes: displacing probes. The specificity of displacing probes could be simply assessed through denaturation analysis before genotyping was implemented, and the probes designed with maximal specificity also showed the greatest detection sensitivity. The ease in design, the simple single-dye labeling chemistry and the capability to adopt degenerated negative strands for point mutation genotyping make the displacing probes both cost effective and easy to use. The feasibility of this method was first tested by detecting the C282Y mutation in the human hemochromatosis gene. The robustness of this approach was then validated by simultaneous genotyping of five different types of mutation in the human ?-globin gene. Sixty-two human genomic DNA samples with nine known genotypes were accurately detected, 32 random clinical samples were successfully screened and 114 double-blind DNA samples were all correctly genotyped. The combined merits of reliability, flexibility and simplicity should make this method suitable for routine clinical testing and large-scale genetic screening.

Cheng, Jinping; Zhang, Yongyou; Li, Qingge

2004-01-01

294

Displacement thresholds in central and peripheral vision during tracking  

NASA Technical Reports Server (NTRS)

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.

Haines, R. F.

1986-01-01

295

Crustal Displacements Due to Continental Water Loading  

NASA Technical Reports Server (NTRS)

The effects of long-wavelength (> 100 km), seasonal variability in continental water storage on vertical crustal motions are assessed. The modeled vertical displacements (delta-r(sub M)) 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 delta-r(sub M) with observed Global Positioning System (GPS) heights (delta-r(sub O)) (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 delta-r(sub O) time series are adjusted by delta-r(sub M), their variances are reduced, on average, by an amount equal to the variance of the delta-r(sub M). Of the delta-r(sub O) 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 delta-r(sub M). The delta-r(sub M) 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.

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

2001-01-01

296

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

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.

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

297

Quantitative evaluation of germanium displacement induced by arsenic implantation using germanium isotope superlattices  

NASA Astrophysics Data System (ADS)

The displacement of germanium (Ge) atoms induced by arsenic (As) ion implantation at room temperature was investigated using Ge isotope superlattices grown by molecular beam epitaxy. The depth profiles of 74Ge isotopes in the 70Ge/ natGe isotope superlattices before and after ion implantation were obtained by secondary ion mass spectrometry. By representing the experimental data using a conventional integral model, Ge atomic displacement as a function of depth was obtained, from which we determined that 0.75 nm is the critical displacement necessary to make the structure appear amorphous under examination by cross-sectional transmission electron microscopy. However, we found that the amorphous Ge layers were recrystallized due to a local elevation of temperature caused by the implantation, which indicates that the samples should be cooled down during implantation to avoid the regrowth of amorphous Ge layers for this analysis.

Kawamura, Yoko; Shimizu, Yasuo; Oshikawa, Hiroyuki; Uematsu, Masashi; Haller, Eugene E.; Itoh, Kohei M.

2009-12-01

298

Displacive radiation-induced structural contraction in nanocrystalline ZrN  

NASA Astrophysics Data System (ADS)

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.

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

2012-07-01

299

Systematic calculation of threshold displacement energies: Case study in rutile  

NASA Astrophysics Data System (ADS)

A generalized and systematic method of calculating threshold displacement energies (Ed) using molecular dynamics simulations has been developed and applied to rutile TiO2. Statistically representative results have been achieved through fine sampling of impact energy and trajectory for each atomic species. Each impact trajectory is drawn from a uniform distribution of points on a unit sphere, along which, primary knock-on atoms (PKAs) with kinetic energies in the range of 20-200 eV were introduced into lattices equilibrated to 300 K. Various definitions of Ed are explored, with values presented as probabilities of defect formation. Results for the Ti PKA agree well with experimental data with a value of Ed at around 69 eV. Simulations of O PKAs contrast greatly with Ti PKAs, with displacements occurring at significantly lower energies, resulting in an O value of Ed at 19 eV. Analysis shows that replacement chains on the O sublattice are a common feature and play a significant role in governing defect formation in rutile.

Robinson, M.; Marks, N. A.; Whittle, K. R.; Lumpkin, G. R.

2012-03-01

300

Nanoscale in-plane displacement evaluation by AFM scanning and digital image correlation processing  

Microsoft Academic Search

A quantitative evaluation of the structure deformation of microfabricated electromechanical systems is important for the design and functional control of microsystems. When the displacement measurement of the microstructure’s surface is to be made in a domain smaller than a few microns, both spatial sampling resolution and measuring sensitivity should reach nanoscale levels. In this paper, an atom force microscope (AFM)

S Chang; C S Wang; C Y Xiong; J Fang

2005-01-01

301

Development and Evolution of Character Displacement  

PubMed Central

Character displacement occurs when competition for either resources or successful reproduction imposes divergent selection on interacting species, causing divergence in traits associated with resource use or reproduction. Here, we describe how character displacement can be mediated either by genetically canalized changes (i.e., changes that reflect allelic or genotype frequency changes) or by phenotypic plasticity. We also discuss how these two mechanisms influence the tempo of character displacement. Specifically, we suggest that, under some conditions, character displacement mediated by phenotypic plasticity might occur more rapidly than that mediated by genetically canalized changes. Finally, we describe how these two mechanisms may act together and determine character displacement’s mode, such that it proceeds through an initial phase in which trait divergence is environmentally induced to a later phase in which divergence becomes genetically canalized. This plasticity-first hypothesis predicts that character displacement should be generally mediated by ancestral plasticity and that it will arise similarly in multiple, independently evolving populations. We conclude by highlighting future directions for research that would test these predictions.

Pfennig, David W.; Pfennig, Karin S.

2012-01-01

302

Modeling averaged displacement fronts in heterogeneous media with multirate mass transfer models  

NASA Astrophysics Data System (ADS)

The morphology of fluid-fluid interfaces during immiscible displacement has been studied intensely on length scales where the pore space is resolved. Depending on the dimensionless numbers of the flow process, the front morphology can be different: compact or irregular with different cluster distributions of trapped displaced fluid. There are also flow regimes with a cross-over from a compact displacing fluid far away from the front and irregular fluid distribution at the front. If displacement is considered on larger length scales, the pore space and fluid-fluid interfaces can no longer be resolved. The front is in this case rather described by an isoline of the displacing fluid saturation. Displacement fronts on large length scales in heterogeneous media can also show complex front morphology: compact or irregular with fluid clusters of displaced fluid that are trapped behind the front. As displaced fluid may also be immobilized (meaning it is not trapped, but it is surrounded by displacing fluid, so that the surrounding material has a very low permeability) and is in this case displaced only very slowly, one also finds a cross-over regime with a compact region far away from the front and an irregular front. The morphology is influenced by the interplay of heterogeneous structure and the stability of the displacement process. We focus on displacement scenarios with crossover from irregular fluid distribution around the front due to immobilized fluid that is eventually displaced to compact far behind the front. To have a quantification of the front morphology is important, for example, to estimate mass transfer of given components between the fluids. We study the front morphology using numerical simulations of displacement processes in porous media composed of two different materials. We consider different heterogeneous structures. We consider flow scenarios with different capillary number and viscosity ratio of the fluids. It is demonstrated that the connectivity of the heterogeneous structure has a crucial influence on the front morphology. For these numerical simulations we compare the averaged fluid distribution to an upscaled one-dimensional model. In the upscaled model, the immobilization of displaced fluid behind the front is captured by a double continuum approach, where the immobilized fluid is considered an immobile continuum. The size of the immobile continuum changes with time. The flow is modeled in the mobile continuum with a multi-rate mass-transfer term to capture exchange with the immobile domain. The rate coefficients for the mass transfer have to be estimated from the size distribution of immobilized fluid clusters. It is demonstrated that such a simplified model can describe the displacement well, if the front morphology is not too complex.

Neuweiler, Insa; Heiss, Veronica; Tecklenburg, Jan

2013-04-01

303

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

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

304

New techniques for the non-contact measurement of displacer motion of a miniature split-Stirling cryocooler  

NASA Astrophysics Data System (ADS)

This paper proposes optional methods to calibrate the static sensitivity of the measurement of displacer motion inside the cold finger of a split-Stirling cryocooler. The relative displacement measurement method, as previously proposed, required that the regenerator matrix material should have such a high magnetic permeability that the linear variable-differential transformer (LVDT) could measure the displacer motion without large signal amplification. This would be impossible for low-permeability materials, e.g. stainless steel 316L and 304L, contained in the displacer. Therefore, three options are proposed for the calibration of static sensitivity: contact, purge or dynamic calibration methods. Temperature compensation is also found to be necessary to transfer the LVDT voltage to the true displacer displacement when performing the non-contact measurement of the displacer motion.

Yang, Y. P.; Huang, B. J.; Chen, F. M.; Chien, S. B.; Shieh, T. F.

305

Anion-exchange displacement centrifugal partition chromatography.  

PubMed

Ion-exchange displacement chromatography has been adapted to centrifugal partition chromatography. The use of an ionic liquid, benzalkonium chloride, as a strong anion-exchanger has proven to be efficient for the preparative separation of phenolic acid regioisomers. Multigram quantities of a mixture of three hydroxycinnamic acid isomers were separated using iodide as a displacer. The displacement process was characterized by a trapezoidal profile of analyte concentration in the eluate with narrow transition zones. By taking advantage of the partition rules involved in support-free liquid-liquid chromatography, a numerical separation model is proposed as a tool for preliminary process validation and further optimization. PMID:15516108

Maciuk, Alexandre; Renault, Jean-Hugues; Margraff, Rodolphe; Trébuchet, Philippe; Zèches-Hanrot, Monique; Nuzillard, Jean-Marc

2004-11-01

306

Efficiency Improvements to the Displacement Based Multilevel Structural Optimization Algorithm  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

307

PDT - PARTICLE DISPLACEMENT TRACKING SOFTWARE  

NASA Technical Reports Server (NTRS)

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.

Wernet, M. P.

1994-01-01

308

Is Stereocilia Velocity or Displacement Feedback Used in the Cochlear Amplifier?  

NASA Astrophysics Data System (ADS)

Outer hair cells (OHC) play an important role in cochlear amplification. The OHC senses stereocilia motion and creates a force feedback to the organ of Corti. It is largely accepted that the stereocilia displacement drives the OHC apical conductance change, which, in turn, drives somatic motility. Recent research shows that the tension gated OHC current exhibits fast adaptation in response to stereocilia displacement. Such an adaptation process resembles a high-pass filter or differentiator, at least for the inward current. Since velocity is the derivative of displacement, fast adaptation may indicate that it is the stereocilia velocity, rather than displacement is the more important driver of the OHC apical conductance. We changed our multi-compartment, piezo-electro-mechanical model to sense stereocilia velocity rather than displacement. This new model can well match measured basilar membrane velocity and our own cochlear microphonic data.

Lu, Shan; Mountain, David; Hubbard, Allyn

2009-02-01

309

Multiphoton Production and Detection of Atoms.  

National Technical Information Service (NTIS)

The production of atomic fragments from a compound using multiphoton dissociation was investigated for metal centered and hetero atom centered compounds. The atoms were detected by multiphoton ionization. Metal centered systems generated large amounts of ...

P. C. Engelking

1985-01-01

310

Te atom splitting and modulated structure in calaverite  

Microsoft Academic Search

By a crystal structure refinement of calaverite, (Au, Ag) Te2, it was found that Te atom is split symmetrically to the both-side of mirror plane where Te atoms are supposed to exist. We assumed a regular wavy displacement of Te atom in the calaverite structure and tried to explain the superstructure observed in this mineral.

Shigeho Sueno; Mitsuyoshi Kimata; Masaaki Ohmasa

1979-01-01

311

Bucky gel actuator displacement: experiment and model  

NASA Astrophysics Data System (ADS)

Bucky gel actuator (BGA) is a dry electroactive nanocomposite which is driven with a few volts. BGA’s remarkable features make this tri-layered actuator a potential candidate for morphing applications. However, most of these applications would require a better understanding of the effective parameters that influence the BGA displacement. In this study, various sets of experiments were designed to investigate the effect of several parameters on the maximum lateral displacement of BGA. Two input parameters, voltage and frequency, and three material/design parameters, carbon nanotube type, thickness, and weight fraction of constituents were selected. A new thickness ratio term was also introduced to study the role of individual layers on BGA displacement. A model was established to predict BGA maximum displacement based on the effect of these parameters. This model showed good agreement with reported results from the literature. In addition, an important factor in the design of BGA-based devices, lifetime, was investigated.

Ghamsari, A. K.; Jin, Y.; Zegeye, E.; Woldesenbet, E.

2013-02-01

312

Nonlinear stability analysis of miscible displacements  

Microsoft Academic Search

A simulator for three-dimensional horizontal miscible displacements in porous media is developed. Using this simulator, we examine the initiation and development of instabilities, viscous fingers and gravity tongues.

Shih-Hsien Chang; John C. Slattery

1990-01-01

313

Hydrocarbon Displacement by Carbon Dioxide Dispersions.  

National Technical Information Service (NTIS)

The US Department of Energy's (DOE) Morgantown Energy Technology Center (METC) is investigating methods to control the mobility of carbon dioxide for use in gas miscible displacements of hydrocarbons that are found in petroleum reservoirs. Carbon dioxide ...

J. R. Duda

1986-01-01

314

Computer Simulation of High Energy Displacement Cascades.  

National Technical Information Service (NTIS)

A methodology developed for modeling many aspects of high energy displacement cascades with molecular level computer simulations is reviewed. The initial damage state is modeled in the binary collision approximation (using the MARLOWE computer code), and ...

H. L. Heinisch

1988-01-01

315

Atmospheric pressure loading displacement of SLR stations  

Microsoft Academic Search

This paper addresses the local displacement at ground stations of the world-wide Satellite Laser Ranging (SLR) network induced by atmospheric pressure variations. Since currently available modelling options do not satisfy the requirements for the target application (real-time availability, complete coverage of SLR network), a new representation is developed. In a first step, the 3-dimensional displacements are computed from a 6-hourly

D. Bock; R. Noomen; H.-G. Scherneck

2005-01-01

316

Earthquake-induced soil displacements and their impact on rehabilitations.  

PubMed

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

Konagai, Kazuo

2011-01-01

317

A 3D nano driving system with large-stroke  

NASA Astrophysics Data System (ADS)

To satisfy the need of precision displacement, a 3D Nano driving system, which including metrological vertical scanning system and coplanar 2D precision stage with large-stroke and nanopositioning resolution, is developed in this paper. The coarse-fine dual-stage actuators have been applied in the 3D Nano driving system in X, Y and Z directions. The servomotors combining with precision lead screws and linear guides are used to actuate the coarse driving, and piezoelectric actuators combining with parallel board flexure hinges are used to actuate the fine driving. Three laser interferometers are used to measure the displacement in X, Y and Z directions respectively. The structure and principle of the system is introduced and the displacement range and displacement resolution of the system are also analyzed in details. The 3D Nano driving system has been successfully applied in the white light interference based atomic force probe scanning measurement system for ultra-precision surface topography developed in our laboratory. The experimental results show that the nano-driving in X, Y, Z directions can be realized by the 3D Nano driving system.

Wang, Shuzhen; Du, Ziqiang; Xie, Tiebang

2011-08-01

318

Frequency response of polypyrrole trilayer actuator displacement  

NASA Astrophysics Data System (ADS)

Conducting polymer trilayers are attractive for use in functional devices, given low actuation voltages, operation in air and potentially useful stresses and strains; however, their dynamic behavior must be understood from an engineering perspective before they can be effectively incorporated into a design. As a step towards the identification of the actuator dynamics, frequency response analysis has been performed to identify the magnitude and phase shift of displacement in response to a sinusoidal voltage input. The low damping of the trilayer operating in air and the use of a laser displacement sensor has allowed the frequency response to be continuously identified up to 100Hz, demonstrating a resonant peak at 80Hz for a 10mm long actuator. Two linear transfer function models have been fitted to the frequency response of the trilayer displacement (i) a 3rd order model to represent the dynamics below 20Hz and (ii) a higher complexity 6th order model to also include the resonant peak. In response to a random input signal, the 3rd order model coarsely follows the experimental identified displacement, while the 6th order model is able to fully simulate the real trilayer movement. Step responses have also been obtained for the 3rd and 6th order transfer functions, with both models capable of following the first 4 seconds of experimental displacement. The application of empirical transfer function models will facilitate accurate simulation and analysis of trilayer displacement, and will lead to the design of accurate positional control systems.

John, Stephen; Alici, Gursel; Cook, Christopher

2008-05-01

319

Computer Simulation of Displacement Cascades in Nanocrystalline Ni  

Microsoft Academic Search

Large-scale molecular dynamics of cascade production of the primary damage state are performed in fcc nanocrystalline Ni of average grain diameters of 5 and 12 nm. Primary knock-on atom kinetic energies of 5-30 keV are simulated. During the thermal spike phase, significant atomic motion towards the surrounding grain boundary structure is observed, characterized by many replacement-collision sequences. Upon resolidification, the

M. Samaras; P. M. Derlet; H. van Swygenhoven; M. Victoria

2002-01-01

320

The evolution of fabric with displacement in natural brittle faults  

NASA Astrophysics Data System (ADS)

In experiments performed at room temperature on gouges, a characteristic clast size distribution (CSD) is produced with increasing strain, and shear localization is documented to begin after few millimetres of sliding. But in natural faults active at depth in the crust, mechanical processes are associated with fluid-rock interactions, which might control the deformation and strength recovery. We aim to investigate the microstructural, geochemical and mineralogical evolution of low-displacement faults with increasing shear strain. The faults (cataclasite- and pseudotachylyte-bearing) are hosted in tonalite and were active at 9-11 km and 250-300°C. The samples were collected on a large glacier-polished outcrop, where major faults (accommodating up to 4300 mm of displacement) exploit pre-existing magmatic joints and are connected by a network of secondary fractures and faults (accommodating up to 500 mm of displacement) breaking intact tonalite. We performed optical and cathodoluminescence (CL) microscope, Scanning Electron Microscope (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Rietveld X-Ray Powder Diffraction and microprobe chemical analysis in deformation zones of secondary faults with various offsets in order to evaluate the transfer of chemical species between dissolution zones and protected zones. Image analysis techniques were applied on SEM-BSE and optical microscope images to compute the CSD in samples, which experienced an increasing amount of strain. The secondary fractures are up to 5 mm thick. Within the first 20 mm of displacement, shear localizes along Y and R1 surfaces and a cataclastic foliation develops. The CSD evolves from a fractal dimension D of 1.3 in fractures without visible displacement to values above 2 after the first 500 mm of displacement. Chemical maps and CL images indicate that the foliation in cataclasite results from the rotation and fragmentation of clasts, with dissolution of quartz and passive concentration of Ti oxides and titanite in the foliation planes. The cataclasites are cemented by pervasive precipitation of K-feldspar plagues and idiomorphic, randomly oriented, epidote and chlorite. We conclude that the textures of these small displacement (< 500 mm) faults are controlled by brittle processes (fracture propagation and cataclastic comminution) similar to those reproduced in friction experiments performed on granite gouge (e.g., Beeler et al., 1996; Logan, 2007). Then progressively, stress driven fluid-rock reactions develop as fracturing and grain size reduction allows the kinetics of these reactions to be more efficient and fracture interconnection allows fluid infiltration. Healing of microfractures and fault rock cementation caused a rapid posteismic recovery of fault strength. References Beeler, N.M., Tullis, T.E., Blanpied, L., Weeks, J.D., 1996. Frictional behaviour of large displacement experimental faults. Journal of Geophysical Research 101, B4, 8697-8715. Logan, J.M., 2007. The progression from damage to localization of displacement observed in laboratory testing of porous rocks, in Lewis, H., and Couples, G.D. (eds.) The relationship between damage and localization. Geological Society of London Special Publication 289, 75-87.

Mittempergher, S.; Di Toro, G.; Gratier, J.; Aretusini, S.; Boullier-Bertrand, A.

2011-12-01

321

Modified Newmark method involving excess pore pressure to express unlimited landslide displacement  

NASA Astrophysics Data System (ADS)

Newmark method is the most popular approach to assess the displacement of landslides induced by earthquakes using seismic acceleration, slope inclination, and friction parameters. However, this method always shows limited shear displacement no matter how the acceleration is large and duration is long. This is partly because it does not include any pore pressure, especially excess pore water pressure generated under long shear displacement. As shown by series of earthquake wave-form loading undrained ring shear tests by Disaster Prevention Research Institute of Kyoto University, grain crushing or soil skelton collapse can contribute to generation of high excess pore pressure and let the soil to reach liquefaction state ("Sliding surface liquefaction"). Many of unlimited landslide displacement have been revealed that this phenomena must be the key mechanism. In the test series of mixture of silica sands and dry-ice pellets (frozen carbon-dioxide), for studying the mechanism of the gasification of methane hydrates in the submarine landslides which likely to trigger large scale submarine landslides, authors have found linear relationship between log of excess pore pressure ratio (generated pore pressure / initial effective normal stress) and log of shear displacement. By embedding this relation into the Newmark method, unlimited shear displacement can appear under certain slope inclination and exaggerated acceleration. Authors show there is critical slope inclination for unlimited displacement when given acceleration waveform.

Fukuoka, H.; Tsukui, A.

2012-12-01

322

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

Code of Federal Regulations, 2010 CFR

...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...

2009-07-01

323

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

Code of Federal Regulations, 2010 CFR

...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...

2009-07-01

324

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

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

325

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

Code of Federal Regulations, 2010 CFR

...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...

2010-07-01

326

Atom-by-atom assembly  

NASA Astrophysics Data System (ADS)

Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to ‘see’ individual atoms by means of imaging, but is also a tool that is used to ‘touch’ and ‘take’ the atoms, or to ‘hear’ their movements. Therefore, the STM can be considered as the ‘eyes’, ‘hands’ and ‘ears’ of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed.

Hla, Saw Wai

2014-05-01

327

Atom-by-atom assembly.  

PubMed

Atomic manipulation using a scanning tunneling microscope (STM) tip enables the construction of quantum structures on an atom-by-atom basis, as well as the investigation of the electronic and dynamical properties of individual atoms on a one-atom-at-a-time basis. An STM is not only an instrument that is used to 'see' individual atoms by means of imaging, but is also a tool that is used to 'touch' and 'take' the atoms, or to 'hear' their movements. Therefore, the STM can be considered as the 'eyes', 'hands' and 'ears' of the scientists, connecting our macroscopic world to the exciting atomic world. In this article, various STM atom manipulation schemes and their example applications are described. The future directions of atomic level assembly on surfaces using scanning probe tips are also discussed. PMID:24787453

Hla, Saw Wai

2014-05-01

328

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

NASA Astrophysics Data System (ADS)

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.

Kim, Junhee; Kim, Kiyoung; Sohn, Hoon

2014-01-01

329

An expanded calibration study of the explicitly correlated CCSD(T)-F12b method using large basis set standard CCSD(T) atomization energies  

NASA Astrophysics Data System (ADS)

The effectiveness of the recently developed, explicitly correlated coupled cluster method CCSD(T)-F12b is examined in terms of its ability to reproduce atomization energies derived from complete basis set extrapolations of standard CCSD(T). Most of the standard method findings were obtained with aug-cc-pV7Z or aug-cc-pV8Z basis sets. For a few homonuclear diatomic molecules it was possible to push the basis set to the aug-cc-pV9Z level. F12b calculations were performed with the cc-pVnZ-F12 (n = D, T, Q) basis set sequence and were also extrapolated to the basis set limit using a Schwenke-style, parameterized formula. A systematic bias was observed in the F12b method with the (VTZ-F12/VQZ-F12) basis set combination. This bias resulted in the underestimation of reference values associated with small molecules (valence correlation energies <0.5 Eh) and an even larger overestimation of atomization energies for bigger systems. Consequently, caution should be exercised in the use of F12b for high accuracy studies. Root mean square and mean absolute deviation error metrics for this basis set combination were comparable to complete basis set values obtained with standard CCSD(T) and the aug-cc-pVDZ through aug-cc-pVQZ basis set sequence. However, the mean signed deviation was an order of magnitude larger. Problems partially due to basis set superposition error were identified with second row compounds which resulted in a weak performance for the smaller VDZ-F12/VTZ-F12 combination of basis sets.

Feller, David; Peterson, Kirk A.

2013-08-01

330

An expanded calibration study of the explicitly correlated CCSD(T)-F12b method using large basis set standard CCSD(T) atomization energies.  

PubMed

The effectiveness of the recently developed, explicitly correlated coupled cluster method CCSD(T)-F12b is examined in terms of its ability to reproduce atomization energies derived from complete basis set extrapolations of standard CCSD(T). Most of the standard method findings were obtained with aug-cc-pV7Z or aug-cc-pV8Z basis sets. For a few homonuclear diatomic molecules it was possible to push the basis set to the aug-cc-pV9Z level. F12b calculations were performed with the cc-pVnZ-F12 (n = D, T, Q) basis set sequence and were also extrapolated to the basis set limit using a Schwenke-style, parameterized formula. A systematic bias was observed in the F12b method with the (VTZ-F12/VQZ-F12) basis set combination. This bias resulted in the underestimation of reference values associated with small molecules (valence correlation energies <0.5 E(h)) and an even larger overestimation of atomization energies for bigger systems. Consequently, caution should be exercised in the use of F12b for high accuracy studies. Root mean square and mean absolute deviation error metrics for this basis set combination were comparable to complete basis set values obtained with standard CCSD(T) and the aug-cc-pVDZ through aug-cc-pVQZ basis set sequence. However, the mean signed deviation was an order of magnitude larger. Problems partially due to basis set superposition error were identified with second row compounds which resulted in a weak performance for the smaller VDZ-F12/VTZ-F12 combination of basis sets. PMID:24006977

Feller, David; Peterson, Kirk A

2013-08-28

331

Phase separation and vortex states in binary mixture of Bose-Einstein condensates in trapping potentials with displaced centers  

Microsoft Academic Search

A system of two simultaneously trapped condensates consisting of 87Rb atoms in two different hyperfine states is investigated theoretically in the case where the minima of the trapping potentials\\u000a are displaced with respect to each other. It is shown that the small shift of the minima of the trapping potentials leads\\u000a to a considerable displacement of the centers of mass

S. T. Chui; V. N. Ryzhov; E. E. Tareyeva

2002-01-01

332

A uniaxial bioMEMS device for imaging single cell response during quantitative force-displacement measurements  

Microsoft Academic Search

A microfabricated device has been developed for imaging of a single, adherent cell while quantifying force under an applied\\u000a displacement. The device works in a fashion similar to that of a displacement-controlled uniaxial tensile machine. The device\\u000a was calibrated using a tipless atomic force microscope (AFM) cantilever and shows excellent agreement with the calculated\\u000a spring constant. A step input was

David B. Serrell; Jera Law; Andrew J. Slifka; Roop L. Mahajan; Dudley S. Finch

2008-01-01

333

A Novel “Subset Splitting” Procedure for Digital Image Correlation on Discontinuous Displacement Fields  

Microsoft Academic Search

Digital Image Correlation (DIC) is an easy to use yet powerful approach to measure displacement and strain fields. While the\\u000a method is robust and accurate for a variety of applications, standard DIC returns large error and poor correlation quality\\u000a near displacement discontinuities such as cracks or shear bands. This occurs because the subsets used for correlation can\\u000a only capture continuous

J. Poissant; F. Barthelat

2010-01-01

334

Dependence of radiation damage accumulation in iron on underlying models of displacement cascades and subsequent defect migration  

NASA Astrophysics Data System (ADS)

Groups of displacement cascades calculated independently with different simulation models and computer codes are compared on a statistical basis. The parameters used for this comparison are the number of Frenkel pairs (FP) produced, the percentages of vacancies and self-interstitial atoms (SIAs) in clusters, the spatial extent and the aspect ratio of the vacancies and the SIAs formed in each cascade. One group of cascades was generated in the binary collision approximation (BCA) and all others by full molecular dynamics (MD). The MD results differ primarily due to the empirical interatomic potentials used and, to some extent, in code strategies. Cascades were generated in simulation boxes at different initial equilibrium temperatures. Only modest differences in the predicted numbers of FP are observed, but the other cascade parameters may differ by more than 100%. The consequences of these differences on long-term cluster growth in a radiation environment are examined by means of object kinetic Monte Carlo (OKMC) simulations. These were repeated with three different parameterizations of SIA and SIA cluster mobility. The differences encompassed low to high mobility, one- and three-dimensional migration of clusters, and complete immobility of large clusters. The OKMC evolution was followed until 0.1 dpa was reached. With the range of OKMC parameters used, cluster populations after 0.1 dpa differ by orders of magnitude. Using the groups of cascades from different sources induced no difference larger than a factor of 2 in the OKMC results. No correlation could be identified between the cascade parameters considered and the number densities of vacancies and SIAs predicted by OKMC to cluster in the long term. However, use of random point defect distributions instead of those obtained for displacement cascades as input for the OKMC modeling led to significantly different results. It is therefore suggested that although the displacement cascade characteristics considered do not correlate with cluster populations in the long term, other aspects of the internal structure of cascades do.

Souidi, A.; Becquart, C. S.; Domain, C.; Terentyev, D.; Malerba, L.; Calder, A. F.; Bacon, D. J.; Stoller, R. E.; Osetsky, Yu. N.; Hou, M.

2006-09-01

335

Experimental investigation of local displacement speeds of wrinkled unsteady flames  

NASA Astrophysics Data System (ADS)

Local flame displacement speeds were measured along the flame front of laminar unsteady premixed flames wrinkled by laminar toroidal vortices. The displacement speed is argued to be the most important and sensitive parameter that must be simulated correctly in numerical simulation of turbulent flames. An axisymetric flame wrinkle is created in order to measure all components of the normal velocity vector and stretch; particle image velocimetry (PIV) and high-speed shadowgraph cinematography yield the difference between the interface velocity and the reactant gas velocity---the displacement speed. This repeatable flame-vortex interaction problem provides a useful test data to assess direct numerical simulation models and flame stretch theory. Lean and rich methane-air, and lean propane-air flames were investigated to assess stable and unstable preferential diffusion effects on local displacement speeds. The strength of the laminar toroidal vortices was varied from 1.4 to 10 times the unstretched laminar flame burning velocities, S L. Results showed that the local displacement speeds follow the trends predicted by the laminar steady-state theory, but not the magnitudes. Large variations in local displacement speed measurements were found, ranging from --6 to 10 times SL. The negative values occur at the two locations that the steady-state theory predicts low values. Planar laser induced fluorescence of the OH radical was used successfully to locate the flame front boundary in the velocity fields obtained from the PIV images. Microgravity studies at NASA Lewis 2.2 second drop tower showed that when the stabilizing influence of buoyancy is removed, the wrinkling amplitude of the premixed flames caused by toroidal vortices increases by as much as a factor of three. The degree of wrinkling for preferential diffusion unstable flames is larger than those showed by stable ones. Vorticity fields obtained from the PIV images (at one-g) indicate that baroclinic torques due to buoyancy create "flame-generated vorticity" which induces a velocity that suppresses flame wrinkles. Scaling concepts indicate that the ratio of Baroclinic torques to the Rayleigh-Taylor stabilizing force scales inversely with Froude number. In the present experiment, the velocity induced by Baroclinic torques is equal to that induced by the Rayleigh-Taylor forces. Thus, baroclinic torques in this experiment are important but not dominant.

Sinibaldi, Jose Oscar

336

Ultra-Sensitive Magnetoresistive Displacement Sensing Device  

NASA Technical Reports Server (NTRS)

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.

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

2003-01-01

337

A displacement spindle in a micro/nano level  

NASA Astrophysics Data System (ADS)

This paper presents two micro/nano level displacement sensors, which consist of a mini LDGI (linear diffraction grating interferometer) and a focus probe. These two sensors are integrated into the spindle system of a micro/nano-CMM. This micro/nano spindle system is fixed on a rectangular granite bridge to achieve the z-axis function. The motion of the spindle is driven by an ultrasonic motor on a precision cross-roller slide. Its displacement is fed back by the LDGI. A DVD pick-up head is modified with its S-curve principle as the non-contact focus probe. Mounting the probe onto the spindle head, it is possible to achieve a large displacement and nanoresolution measuring spindle system with a feedback nanomotion control scheme. After accuracy calibration and error compensation, the spindle motion to 10 mm can perform 10 nm positioning accuracy and 30 nm measurement accuracy. Experiments on some ultraprecision profiles have shown the capability of this spindle system.

Fan, Kuang-Chao; Lai, Zi-Fa; Wu, Peitsung; Chen, Yung-Chang; Chen, Yejin; Jäger, Gerd

2007-06-01

338

Atom Interferometers  

Microsoft Academic Search

Interference with atomic and molecular matter waves is a rich branch of\\u000aatomic physics and quantum optics. It started with atom diffraction from\\u000acrystal surfaces and the separated oscillatory fields technique used in atomic\\u000aclocks. Atom interferometry is now reaching maturity as a powerful art with\\u000amany applications in modern science. In this review we first describe the basic\\u000atools

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

2007-01-01

339

Atom Interferometry  

Microsoft Academic Search

The first demonstrated atom interferometers, reported in 1991 by [1] and [2] were based on the diffraction of atoms with micro fabricated structures. This class of atom interferometers is analogous\\u000a to optical interferometers, where slits or diffraction gratings have been used to divide and recombine beams of atoms. The\\u000a gratings and slits can be either material structures or periodic light

S. Chu

340

Atomic-scale study of electric dipoles near charged and uncharged domain walls in ferroelectric films.  

PubMed

Ferroelectrics are materials exhibiting spontaneous electric polarization due to dipoles formed by displacements of charged ions inside the crystal unit cell. Their exceptional properties are exploited in a variety of microelectronic applications. As ferroelectricity is strongly influenced by surfaces, interfaces and domain boundaries, there is great interest in exploring how the local atomic structure affects the electric properties. Here, using the negative spherical-aberration imaging technique in an aberration-corrected transmission electron microscope, we investigate the cation-oxygen dipoles near 180 degrees domain walls in epitaxial PbZr(0.2)Ti(0.8)O(3) thin films on the atomic scale. The width and dipole distortion across a transversal wall and a longitudinal wall are measured, and on this basis the local polarization is calculated. For the first time, a large difference in atomic details between charged and uncharged domain walls is reported. PMID:18066068

Jia, Chun-Lin; Mi, Shao-Bo; Urban, Knut; Vrejoiu, Ionela; Alexe, Marin; Hesse, Dietrich

2008-01-01

341

Gas miscible displacement enhanced oil recovery: Technology status report  

SciTech Connect

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.

Not Available

1986-10-01

342

Catalytic Molecular Logic Devices by DNAzyme Displacement.  

PubMed

Chemical reactions catalyzed by DNAzymes offer a route to programmable modification of biomolecules for therapeutic purposes. To this end, we have developed a new type of catalytic DNA-based logic gates in which DNAzyme catalysis is controlled via toehold-mediated strand displacement reactions. We refer to these as DNAzyme displacement gates. The use of toeholds to guide input binding provides a favorable pathway for input recognition, and the innate catalytic activity of DNAzymes allows amplification of nanomolar input concentrations. We demonstrate detection of arbitrary input sequences by rational introduction of mismatched bases into inhibitor strands. Furthermore, we illustrate the applicability of DNAzyme displacement to compute logic functions involving multiple logic gates. This work will enable sophisticated logical control of a range of biochemical modifications, with applications in pathogen detection and autonomous theranostics. PMID:24692254

Brown, Carl W; Lakin, Matthew R; Stefanovic, Darko; Graves, Steven W

2014-05-01

343

Forced displacement and women's security in Colombia.  

PubMed

In the protracted Colombian conflict, assistance to internally displaced persons has developed in the context of contradictory political processes. The Colombian government's launching of a transitional justice process in the midst of armed conflict has generated a complex situation displaying both conflict and post-conflict characteristics. The progressive Constitutional Court rulings on internal displacement, in particular the gender-sensitive Auto 092, constitute an attempt to bring together humanitarian interventions and transitional justice measures in a rights-based framework. However, the national government is reluctant to adopt them fully and local realities still hamper their integrated implementation. Displaced women, therefore, remain in an especially vulnerable position. This paper argues that gender-sensitive humanitarian interventions must take into account all of these complexities of scale and political process in order to make legal frameworks more effective at the local level. In these contexts, interventions should pay particular attention to strategies that contribute to transforming pre-existing gender regimes. PMID:20132270

Meertens, Donny

2010-04-01

344

Transverse sacral fractures with anterior displacement  

PubMed Central

Transverse fractures of the sacrum with anterior displacement are the rarest type of transverse sacral fractures. They usually occur at the S1–S2 region in suicide jumpers. A clinical study was performed to evaluate the diagnosis, treatment and outcome of transverse sacral fractures with anterior displacement. We present six patients with a transverse fracture of the sacrum with anterior displacement. All patients presented with bowel and bladder dysfunction, perineal anesthesia, sensory and motor deficits at the lower extremities. Prompt diagnosis of the sacral fracture was obtained in five of the six patients. Operative treatment including lumbosacral laminectomies, spine instrumentation and fusion was done in all patients. Neurological recovery was almost complete in one patient, incomplete in four patients, and none in one patient. Although reduction of the fracture was not ideal in many of these patients, long-term clinical and radiographic follow-up, and neurological improvement were rewarding.

Sapkas, George S.; Mavrogenis, Andreas F.

2007-01-01

345

Hadronic Atoms  

NASA Astrophysics Data System (ADS)

We review the theory of hadronic atoms in the framework of quantum chromodynamics, with photons and electrons included (QCD+QED). We illustrate the method by means of ?+?- atoms and briefly consider the application of the same approach to several other hadronic atoms.

Gasser, J.; Lyubovitskij, V. E.; Rusetsky, A.

2009-11-01

346

Atomic Interferometers  

Microsoft Academic Search

We examine the role of laser phase in multiphoton excitation of atomic transitions. Closed loops in excitation linkages create interfering channels which depend on atomic and laser phases. Such phase-dependent dynamics suggest the use of these transition linkages as atomic interferometers in which states can be decoupled (and population trapped). We show how phase and amplitude measurements are possible in

S. J. Buckle; S. M. Barnett; P. L. Knight; M. A. Lauder; D. T. Pegg

1986-01-01

347

Atom interferometers  

Microsoft Academic Search

Atom interferometers have opened up new areas of fundamental and applied research. As well known from photon optics, multiple-beam interferometers offer an increased sensitivity on the relative phases between interfering waves. Very recently, first atomic multiple-beam interferometers were realized. These concepts are based on an atomic beam that is spatially split into coherent partial de Broglie waves, where the number

J. Lone; K. Sengstock; W. Ertmer

1998-01-01

348

Molecular dynamics simulation of displacement cascades in UO2  

NASA Astrophysics Data System (ADS)

The primary damage induced within a uranium dioxide matrix subjected to a flux of energetic ions was investigated by classical molecular dynamics. UO2 was modeled using the set of empirical potentials based on a rigid ion model. Displacement cascades were initiated by accelerating a uranium primary knock-on atom to a kinetic energy up to 100 keV. It was first shown that the estimated RID a-thermal coefficient is well below those which are deemed relevant for spent nuclear fuels. Cascades were then purposely overlapped within the same simulation box so as to study the response of the material to increasing damage levels. During cascade overlap sequences, the growth of nanometric voids was observed. Obtained results evidenced a radiation damage controlled heterogeneous mechanism for insoluble fission product segregation in UO2.

Martin, Guillaume; Garcia, Philippe; Sabathier, Catherine; Palancher, Hervé; Maillard, Serge

2014-06-01

349

Atomic and electronic structure of oxygen vacancies and Nb-impurity in SrTiO3  

NASA Astrophysics Data System (ADS)

We present the results of a first-principle full-potential linearized augmented plane wave (FLAPW) method to study the effect of defects on the electronic structure of SrTiO3. In addition, the relaxation of nearest neighbor atoms around those defects were calculated self-consistently. The calculations were performed using the local (spin) density approximations (L(S)DA), for the exchange-correlation potential. SrTiO3 was found to experience an insulator-to-metal transition upon the formation of oxygen vacancies or the substitution of Nb at the Ti site. The formation of oxygen divacancy disclosed additional states below the conduction band edge. The crystalline lattice relaxation showed displacements of atoms in rather large defective region. The magnitudes of atomic movements, however, were not large, normally not exceeding 0.15 Å. Our results were compared to the available experimental observations.

Hamid, A. S.

2009-12-01

350

Displacement sensors using soft magnetostrictive alloys  

SciTech Connect

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.

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

351

Computing Displacements And Strains From Video Images  

NASA Technical Reports Server (NTRS)

Subpixel digital video image correlation (SDVIC) technique for measuring in-plane displacements on surfaces of objects under loads, without contact. Used for analyses of experimental research specimens or actual service structures of virtually any size or material. Only minimal preparation of test objects needed, and no need to isolate test objects from minor vibrations or fluctuating temperatures. Technique implemented by SDVIC software, producing color-graduated, full-field representations of in-plane displacements and partial derivatives with respect to position along both principal directions in each image plane. From representations, linear strains, shear strains, and rotation fields determined. Written in C language.

Russell, Samuel S.; Mcneill, Stephen R.; Lansing, Matthew D.

1996-01-01

352

Wireless Power Transfer during Displacement Using Electromagnetic Coupling in Resonance  

NASA Astrophysics Data System (ADS)

This paper proposes a novel way for achieving wireless power transfer from a transmitting antenna to a receiving antenna. This technique is suitable for charging electric vehicles (EVs) because the proposed antennas can transfer power wirelessly with high efficiencies when the antennas are displaced and have large air gaps. This technique utilizes near-field antennas at resonance; however, this technique is still being perfected. This paper describes this techniques' analysis, its results, as well as the possible antennas that are suitable for EVs.

Imura, Takehiro; Okabe, Hiroyuki; Uchida, Toshiyuki; Hori, Yoichi

353

A simple two-fiber optical displacement sensor  

NASA Technical Reports Server (NTRS)

An optical displacement sensor is described in which only a pair of large-diameter fibers is used rather than a branched bundle of many small-diameter fibers. The basic idea of the two-fiber sensor is that the axes of the fibers are at an angle to one another at the sensor face, rather than parallel as is the case for the many-fiber configuration. The sensitivity of this two-fiber sensor is approximately the same as the most sensitive configuration of the many-fiber sensor.-

Powell, J. A.

1974-01-01

354

Atom interferometers and atom holography  

SciTech Connect

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.

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

355

Quantum atomic dynamics in amorphous silicon; a path-integral Monte Carlo simulation  

Microsoft Academic Search

The quantum dynamics of atoms in amorphous silicon has been addressed by using path-integral Monte Carlo simulations. Structural results (radial distribution functions) found from these simulations agree well with experimental data. We study the quantum delocalization of the silicon atoms around their equilibrium positions. This delocalization is larger for coordination defects (fivefold-coordinated Si atoms). Correlations in the atomic displacements are

Carlos P. Herrero

2000-01-01

356

Atom interferometry  

SciTech Connect

This paper is organized as follows: In Section II we present an elementary treatment of the underlying principles of atom interferometry. The phase evolution of an atomic de Broglie wave and the coherence of an atomic beam are discussed. A beam splitter is a key component in an interferometer. The main techniques used to split an atomic beam coherently are considered in Section III. In Section IV we discuss possible applications of atom interferometry. The second part of the chapter concentrates on existing experiments in atom interferometry. Atom interferometers that have been realized are described, and experiments that use these devices are discussed. The chapter concludes with a summary and outlook. 61 refs., 14 figs.

Adams, C.S.; Carnal, O., Mlynek, J. [Universitaet Konstanz (Germany)

1994-12-31

357

Rhetorics of Displacement: Constructing Identities in Forced Relocations  

ERIC Educational Resources Information Center

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

Powell, Katrina M.

2012-01-01

358

Penn Grade Micellar Displacement Project. Final report  

Microsoft Academic Search

Results of the five year study are presented in this report. The Penn Grade Micellar Displacement Project was a test of a Microemulsion Flooding process on typical post-waterflood Bradford Third Sand Reservoir. The project was located on Pennzoil's Lawry Lease in the heart of the Bradford Field in Northern Pennsylvania. The tertiary oil recovery system was Marathon Oil Company's Maraflood

P. S. Ondrusek; W. T. Paynter

1982-01-01

359

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 ...

360

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 ...

361

A Personal Appearance Program for Displaced Homemakers.  

ERIC Educational Resources Information Center

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…

Fiore, Ann Marie; De Long, Marilyn Revell

1990-01-01

362

Ko Displacement Theory for Structural Shape Predictions  

NASA Technical Reports Server (NTRS)

The development of the Ko displacement theory for predictions of structure deformed shapes was motivated in 2003 by the Helios flying wing, which had a 247-ft (75-m) wing span with wingtip deflections reaching 40 ft (12 m). The Helios flying wing failed in midair in June 2003, creating the need to develop new technology to predict in-flight deformed shapes of unmanned aircraft wings for visual display before the ground-based pilots. Any types of strain sensors installed on a structure can only sense the surface strains, but are incapable to sense the overall deformed shapes of structures. After the invention of the Ko displacement theory, predictions of structure deformed shapes could be achieved by feeding the measured surface strains into the Ko displacement transfer functions for the calculations of out-of-plane deflections and cross sectional rotations at multiple locations for mapping out overall deformed shapes of the structures. The new Ko displacement theory combined with a strain-sensing system thus created a revolutionary new structure- shape-sensing technology.

Ko, William L.

2010-01-01

363

Displacement, velocity, and acceleration transducers for machines  

Microsoft Academic Search

Several types of displacement, velocity, and acceleration transducers are described. These transducers have certain advantages that enable their being used for measurements on machines operating at high speeds of the order of 3000 cycles per minute. The theoretical basis of the different types of transducers is explained and the technical specifications of particular instruments are given. Structural diagrams and circuit

V. I. Ghiu; A. M. Racovita; G. M. Giurovici

1978-01-01

364

Maximizing Displacement: Mass, Volume and Density  

NSDL National Science Digital Library

This is an indoor lab that uses a boat simulation to demonstrate the concepts of mass, volume and density, and their relationship to displacement. It is a problem solving activity that encourages student creativity resulting in a variety of valid solutions.

365

Oil recovery process by miscible displacement  

Microsoft Academic Search

This invention involves a process for displacement and recovery of reservoir oil by injecting a bank of polar organic solvent, a second bank of surfactant, organic additive and water, and a following bank of floodwater to drive the fluids through the formation to the producing well. The preferred polar organic solvent is tertiary amyl alcohol but other similar solvents may

Ayers; R. C. Jr

1971-01-01

366

Displacement Damage in Bipolar Linear Integrated Circuits  

NASA Technical Reports Server (NTRS)

Although many different processes can be used to manufacture linear integrated circuits, the process that is used for most circuits is optimized for high voltage -- a total power supply voltage of about 40 V -- and low cost. This process, which has changed little during the last twenty years, uses lateral and substrate p-n-p transistors. These p-n-p transistors have very wide base regions, increasing their sensitivity to displacement damage from electrons and protons. Although displacement damage effects can be easily treated for individual transistors, the net effect on linear circuits can be far more complex because circuit operation often depends on the interaction of several internal transistors. Note also that some circuits are made with more advanced processes with much narrower base widths. Devices fabricated with these newer processes are not expected to be significantly affected by displacement damage for proton fluences below 1 x 10(exp 12) p/sq cm. This paper discusses displacement damage in linear integrated circuits with more complex failure modes than those exhibited by simpler devices, such as the LM111 comparator, where the dominant response mode is gain degradation of the input transistor. Some circuits fail catastrophically at much lower equivalent total dose levels compared to tests with gamma rays. The device works satisfactorily up to nearly 1 Mrad(Si) when it is irradiated with gamma rays, but fails catastrophically between 50 and 70 krad(Si) when it is irradiated with protons.

Rax, B. G.; Johnston, A. H.; Miyahira, T.

2000-01-01

367

Variable-Displacement Hydraulic Drive Unit  

NASA Technical Reports Server (NTRS)

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.

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

1986-01-01

368

Differential spatial displacement discrimination with interfering stimuli  

Microsoft Academic Search

Differential spatial displacement discrimination thresholds were determined for a configuration of three blobs with Gaussian spatial and temporal contrast envelopes. This task is similar to the well known three-dot alignment hyperacuity task. Thresholds determined in the presence of interfering stimuli were identical to thresholds determined without these flanking stimuli. The thresholds scale linearly with stimulus size over at least two

A. Toet; J. J. Koenderink

1989-01-01

369

Opening Doors for the Displaced Worker.  

ERIC Educational Resources Information Center

Describes the many benefits now available to laid-off and displaced textile and apparel-related workers through the North American Free Trade Agreement's Transitional Adjustment Allowance (NAFTA-TAA), which allows them to attend college for the first time. Examines the effectiveness of the TAA program and concludes that there is room for "cautious…

Moore, Martha Norris

2000-01-01

370

Liquid Propellant Gun, Positive Displacement Single Valve.  

National Technical Information Service (NTIS)

An improved bi-propellant injection system for a liquid propellant gun includes a valve which is positively opened at the start of the injection of the fuel and oxidizer into the gun chamber and held at a predetermined displacement to provide a constant s...

S. E. Ayler J. W. Holtrop

1978-01-01

371

Displacement and the Summation of Frustration.  

National Technical Information Service (NTIS)

An attempt was made to explore the relationship between repeated frustrations and the displacement of aggression. The experiment consisted of a 2 X 2 X 4 factorial design: sex X self-ideal discrepancy X frustration. The four conditions of frustration invo...

P. Worchel

1967-01-01

372

Gage for Measuring Displacements in Rock Samples.  

National Technical Information Service (NTIS)

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...

D. J. Holcomb M. J. McNamee

1985-01-01

373

Displacement Gage for the Rock Mechanics Laboratory.  

National Technical Information Service (NTIS)

A gage for measuring displacements has been developed for use in the rock mechanics laboratory and in the field. The gage consists of a support ring that holds an LVDT (liner variable differential transformer), a mounting screw, and a leaf spring. The gag...

D. J. Holcomb M. J. McNamee

1984-01-01

374

Miscible displacement by high pressure nitrogen injection  

Microsoft Academic Search

Primary oil recovery frequently results in oil recoveries of only 10 to 20% of the original oil in place. Several hydrocarbon miscible methods have been tested and proven successful as a secondary or tertiary method of oil recovery under certain reservoir conditions. The use of nitrogen to develop a high-pressure miscible displacement-type recovery process has been studied in the laboratory.

M. D. Rushing; B. C. Thomasson; B. Reynolds; P. B. Crawford

1977-01-01

375

Miscible displacement by high pressure nitrogen injection  

Microsoft Academic Search

Primary oil recovery frquently results in oil recoveries of only 10 to 20% of the original oil in place. Several hydrocarbon miscible methods have been tested and proven successful as a secondary or tertiary method of oil recovery under certain reservoir conditions. The use of nitrogen to develop a high-pressure miscible displacement-type recovery process has been studied in the laboratory.

M. D. Rushing; B. C. Thomasson; B. Reynolds; P. B. Crawford

1977-01-01

376

Experimental demonstration of ecological character displacement  

Microsoft Academic Search

BACKGROUND: The evolutionary consequences of competition are of great interest to researchers studying sympatric speciation, adaptive radiation, species coexistence and ecological assembly. Competition's role in driving evolutionary change in phenotypic distributions, and thus causing ecological character displacement, has been inferred from biogeographical data and measurements of divergent selection on a focal species in the presence of competitors. However, direct experimental

Jabus G Tyerman; Melanie Bertrand; Christine C Spencer; Michael Doebeli

2008-01-01

377

Laser measurement of building vibration and displacement  

Microsoft Academic Search

This paper considers four laser systems used by the Building Research Establishment to investigate the behavior of structures. Lasers enable remote measurements of vibration and displacement to be taken where access to a structure is difficult or where fire, explosion or structural collapse creates a hazardous environment. Each system will be described and its use illustrated using measurements taken on

Andre J. Bougard; B. R. Ellis

1998-01-01

378

Test Approach Lighting for Displaced Thresholds.  

National Technical Information Service (NTIS)

The purpose of the project was to determine the extent to which multiple semiflush-mounted in-runway lighting fixtures, both steady-burning and condenser-discharge types, could replace above-ground approach lighting fixtures to obtain an interim displaced...

E. L. Reamer

1966-01-01

379

Project Evaluation: Penn Grade Micellar Displacement Project.  

National Technical Information Service (NTIS)

The Penn Grade Micellar Displacement Project tested the micellar/polymer flooding process in a low permeability portion of the Bradford Third Sand reservoir. This test, herein referred to as the Lawry Test, followed the successful test of the micellar/pol...

F. E. Suffridge

1984-01-01

380

Neuropsychological functioning in posttraumatic stress disorder following forced displacement in older adults and their offspring.  

PubMed

The aim of the present study was to investigate neuropsychological performance in an untried trauma sample of older adults displaced during childhood at the end of World War II (WWII) with and without posttraumatic stress disorder (PTSD) as well as transgenerational effects of trauma and PTSD on their offspring. Displaced older adults with (n=20) and without PTSD (n=24) and nondisplaced healthy individuals (n=11) as well as one of their respective offspring were assessed with a large battery of cognitive tests (primarily targeting memory functioning). No evidence for deficits in neuropsychological performance was found in the aging group of displaced people with PTSD. Moreover, no group difference emerged in the offspring groups. Findings may be interpreted as first evidence for a rather resilient PTSD group of older adults that is available for assessment 60 years after displacement. PMID:23896354

Jelinek, Lena; Wittekind, Charlotte E; Moritz, Steffen; Kellner, Michael; Muhtz, Christoph

2013-12-15

381

Uncertainty evaluation of displacement gradients measured by electronic speckle pattern shearing interferometry (ESPSI)  

NASA Astrophysics Data System (ADS)

Electronic speckle pattern shearing interferometry (ESPSI), also known as shearography, is a whole-field optical technique used to generate phase fringe patterns that allow us to evaluate displacement gradients. In this work, we report on a Monte Carlo computer simulation to calculate the standard uncertainties associated with the displacement gradients obtained from the experimental data yielded by ESPSI. The displacements were induced by applying tensile load to a metallic sheet sample. At each point of the illuminated area, the standard uncertainty of the gradient was taken as the standard deviation of the series of outcomes obtained by a large number of gradient evaluations. These evaluations were performed by using sets of values generated according to the probability density functions (PDFs) that we assigned to the experimental data. The reported method to evaluate the uncertainties of the displacement gradients agrees with international recommendations.

Cordero, Raul R.; Labbe, Fernando

2005-06-01

382

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

NASA Astrophysics Data System (ADS)

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 ~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.

Shao, Tao; Tarasenko, Victor F.; Zhang, Cheng; Burachenko, Alexandr G.; Rybka, Dmitry V.; Kostyrya, Igor'D.; Lomaev, Mikhail I.; Baksht, Evgeni Kh.; Yan, Ping

2013-05-01

383

Drinking and displacement: a systematic review of the influence of forced displacement on harmful alcohol use.  

PubMed

This paper systematically reviews evidence about factors associated with harmful alcohol use amongst forcibly displaced persons, including refugees and internally displaced persons. Bibliographic and humanitarian-related databases were searched. The number of quantitative and qualitative studies that were screened and reviewed was 1108. Only 10 studies met inclusion criteria. Risk factors identified included gender, age, exposure to traumatic events and resulting posttraumatic stress disorder, prior alcohol consumption-related problems, year of immigration, location of residence, social relations, and postmigration trauma and stress. The evidence base was extremely weak, and there is a need to improve the quantity and quality of research about harmful alcohol use by forcibly displaced persons. PMID:20469970

Weaver, Heather; Roberts, Bayard

2010-11-01

384

Atomic form factor for twisted vortex photons interacting with atoms  

NASA Astrophysics Data System (ADS)

The relatively new atomic form factor for twisted (vortex) beams, which carry orbital angular momentum (OAM), is considered and compared to the conventional atomic form factor for plane-wave beams that carry only spin angular momentum. Since the vortex symmetry of a twisted photon is more complex that that of a plane wave, evaluation of the atomic form factor is also more complex for twisted photons. On the other hand, the twisted photon has additional parameters, including the OAM quantum number, ?, the nodal radial number, p, and the Rayleigh range, zR, which determine the cone angle of the vortex. This Rayleigh range may be used as a variable parameter to control the interaction of twisted photons with matter. Here we address (i) normalization of the vortex atomic form factor, (ii) displacement of target atoms away from the center of the beam vortex, and (iii) formulation of transition probabilities for a variety of photon-atom processes. We attend to features related to experiments that can test the range of validity and accuracy of calculations of these variations of the atomic form factor. Using the absolute square of the form factor for vortex beams, we introduce a vortex factor that can be directly measured.

Guthrey, Pierson; Kaplan, Lev; McGuire, J. H.

2014-04-01

385

Atomic Microclustering  

NASA Astrophysics Data System (ADS)

Buckminsterfullerene, C60, is a molecule with perfect symmetry made up of 60 carbon atoms arranged in the shape of a soccer ball. The geometric structure of C60 is that of a truncated icosahedron with a single carbon atom occypying each vertex. Such a structure is obtained from an icosahedron by truncating each of the 12 vertices, resulting in a 5-membered ring at the location of each vertex and a 6-membered ring corresponding to each icosahedral face. The molecule exhibits a high degree of stability. The bonding environment of each atom is identical and each atom is located at the intersection of two hexagons and a pentagon. Using numerical methods and atomic potentials of logarithmic type, I will show that the 60 particles spontaneously form 12 clusters of 5 particles per cluster. The stability of this buckyball configuration is highly sensitive to the atomic interaction law, which calculations based solely on adjacency eigenvalues do not reveal.

Khushalani, Bharat

2004-05-01

386

NEUTRON DIFFRACTION STUDIES OF THE ACTINIDE OXIDES. II. THERMAL MOTIONS OF THE ATOMS IN URANIUM DIOXIDE AND THORIUM DIOXIDE BETWEEN ROOM TEMPERATURE AND 1100 C  

Microsoft Academic Search

The mean-square thermal displacements of the atoms in UOâ and ThO\\/; sub 2\\/ were determined as a function of temperature from the analysis of two-; dimensional diffraction data. In the range investigated, 20 to 1100 deg C, the ; oxygen atoms vibrate more strongly than the metal atoms and at each temperature ; the displacements of the metal and oxygen

B. T. M. Willis; B. T. M

1963-01-01

387

Real-time displacement measurements with a Fabry-Perot cavity and a diode laser  

Microsoft Academic Search

We present the basic operating principles of a traceable measurement system suitable for use with atomic force microscopes (AFMs) and nanometer-resolution displacement sensors. Our method is based upon a tunable external-cavity diode laser system which is servo-locked via a phase-modulated heterodyne locking technique to a Fabry-Perot interferometer cavity. We discuss mechanical considerations for the use of this cavity as a

Lowell Howard; Jack Stone; Joe Fu

2001-01-01

388

Atomistic modeling of displacement cascades in La2Zr2O7 pyrochlore  

Microsoft Academic Search

An empirical potentials molecular dynamics method was used to simulate the alpha-recoil effects in the lanthanum zirconate pyrochlore La2Zr2O7, at 350 K, where a tetravalent uranium ion was used as the primary knock-on atom with a kinetic energy of 6 keV. The displacement cascades simulations have been carried out along four different crystallographic directions. A detailed analysis indicates that the

Alain Chartier; Constantin Meis; Jean-Paul Crocombette; Louis R. Corrales; William J. Weber

2003-01-01

389

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

NASA Astrophysics Data System (ADS)

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.

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

1999-08-01

390

Computer simulation of displacement cascades in nanocrystalline ni.  

PubMed

Large-scale molecular dynamics of cascade production of the primary damage state are performed in fcc nanocrystalline Ni of average grain diameters of 5 and 12 nm. Primary knock-on atom kinetic energies of 5-30 keV are simulated. During the thermal spike phase, significant atomic motion towards the surrounding grain boundary structure is observed, characterized by many replacement-collision sequences. Upon resolidification, the excess volume condenses to form vacancy dominated defects with a complex partial dislocation network forming at higher energies. PMID:11909475

Samaras, M; Derlet, P M; Van Swygenhoven, H; Victoria, M

2002-03-25

391

Computer Simulation of Displacement Cascades in Nanocrystalline Ni  

NASA Astrophysics Data System (ADS)

Large-scale molecular dynamics of cascade production of the primary damage state are performed in fcc nanocrystalline Ni of average grain diameters of 5 and 12 nm. Primary knock-on atom kinetic energies of 5-30 keV are simulated. During the thermal spike phase, significant atomic motion towards the surrounding grain boundary structure is observed, characterized by many replacement-collision sequences. Upon resolidification, the excess volume condenses to form vacancy dominated defects with a complex partial dislocation network forming at higher energies.

Samaras, M.; Derlet, P. M.; van Swygenhoven, H.; Victoria, M.

2002-03-01

392

Minimally displaced clavicle fracture after high-energy injury: Are they likely to displace?  

PubMed Central

Background Nondisplaced or minimally displaced clavicle fractures are often considered to be benign injuries. These fractures in the trauma patient population, however, may deserve closer follow-up than their low-energy counterparts. We sought to determine the initial assessment performed on these patients and the rate of subsequent fracture displacement in patients sustaining high-energy trauma when a supine chest radiograph on initial trauma survey revealed a well-aligned clavicle fracture. Methods We retrospectively reviewed the cases of trauma alert patients who sustained a midshaft clavicle fracture (AO/OTA type 15-B) with less than 100% displacement treated at a single level 1 trauma centre between 2005 and 2010. We compared fracture displacement on initial supine chest radiographs and follow-up radiographs. Orthopedic consultation and the type of imaging studies obtained were also recorded. Results Ninety-five patients with clavicle fractures met the inclusion criteria. On follow-up, 57 (60.0%) had displacement of 100% or more of the shaft width. Most patients (63.2%) in our study had an orthopedic consultation during their hospital admission, and 27.4% had clavicle radiographs taken on the day of admission. Conclusion Clavicle fractures in patients with a high-energy mechanism of injury are prone to fracture displacement, even when initial supine chest radiographs show nondisplacement. We recommend clavicle films as part of the initial evaluation for all patients with clavicle fractures and early follow-up within the first 2 weeks of injury.

Riehl, John T.; Athans, Bill J.; Munro, Mark W.; Langford, Joshua R.; Kupiszewski, Stanley J.; Haidukewych, George J.; Koval, Kenneth J.

2014-01-01

393

Combining two types of molecular dynamics for rapid computation of high-energy displacement cascades. II. Application of the method to a 70-keV cascade in a simplified nuclear glass  

NASA Astrophysics Data System (ADS)

A combined molecular dynamics method is proposed to accelerate the computation of displacement cascades in nuclear glass arising from recoil nuclei in the 70-100 keV energy range. The method combines two types of molecular dynamics calculations: classical MD with standard empirical potentials and a simplified form with the potentials reduced to their short-range component to estimate the morphology of a displacement cascade. With this method we were able to reconstitute the behavior of a simplified oxide glass impacted by a 70-keV projectile. Compared with the results obtained by classical molecular dynamics, mechanisms observed at lower energies (temporary depolymerization followed by progressive structure recovery) are correctly reproduced at 70 keV; the number of atom displacements and the intermediate depolymerization peak intensity remain linear at energies ranging from 0 to 70 keV. The large volume of the 70-keV cascade allowed us to demonstrate that structure recovery was not homogeneous: the coolest regions were less annealed than the hottest regions. The residual depolymerization was more intense in regions struck by lower-energy projectiles—i.e., at the end of the cascade. Local thermal agitation in the hottest regions rapidly diminished as it propagated, and the neighboring regions were largely unaffected. Thermal agitation in the hottest regions thus had little effect on the recovery of regions impacted by low-energy projectiles.

Delaye, J.-M.; Ghaleb, D.

2005-06-01

394

Simulation of neutron displacement damage in bipolar junction transistors using high-energy heavy ion beams.  

SciTech Connect

Electronic components such as bipolar junction transistors (BJTs) are damaged when they are exposed to radiation and, as a result, their performance can significantly degrade. In certain environments the radiation consists of short, high flux pulses of neutrons. Electronics components have traditionally been tested against short neutron pulses in pulsed nuclear reactors. These reactors are becoming less and less available; many of them were shut down permanently in the past few years. Therefore, new methods using radiation sources other than pulsed nuclear reactors needed to be developed. Neutrons affect semiconductors such as Si by causing atomic displacements of Si atoms. The recoiled Si atom creates a collision cascade which leads to displacements in Si. Since heavy ions create similar cascades in Si we can use them to create similar damage to what neutrons create. This LDRD successfully developed a new technique using easily available particle accelerators to provide an alternative to pulsed nuclear reactors to study the displacement damage and subsequent transient annealing that occurs in various transistor devices and potentially qualify them against radiation effects caused by pulsed neutrons.

Doyle, Barney Lee; Buller, Daniel L.; Hjalmarson, Harold Paul; Fleming, Robert M; Bielejec, Edward Salvador; Vizkelethy, Gyorgy

2006-12-01

395

Character displacement of Cercopithecini primate visual signals.  

PubMed

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

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

2014-01-01

396

Wirelessly Interrogated Position or Displacement Sensors  

NASA Technical Reports Server (NTRS)

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.

Woodard, Stanley E.; Taylor, Bryant D.

2007-01-01

397

Remember Me: Displaced Children of the Holocaust  

NSDL National Science Digital Library

The United States Holocaust Museum (USHM) has worked on a number of important projects, and this might be one of their most moving. Working with the archives of the World Jewish Congress (WJC), they have digitized approximately 1100 photographs of children who were displaced or orphaned as a result of the persecution carried out by the Nazis and their collaborators. The intent of this project is "to identify these children, piece together information about their wartime and postwar experiences, and facilitate renewed connections among these young survivors, their families, and other individuals who were involved in their care during and after the war." Visitors to the site can browse the photos by name or just by viewing the gallery as they see fit. The site also includes a 1945 BBC radio broadcast seeking relatives of displaced children and a section with updates on the project's progress.

398

Wireless Measurement of Rotation and Displacement Rate  

NASA Technical Reports Server (NTRS)

A magnetic field response sensor is designed to measure displacement or rotation rate without a physical connection to a power source, microprocessor, data acquisition equipment, or electrical circuitry. The sensor works with the magnetic field response recorder, which was described in Magnetic-Field-Response Measurement-Acquisition System, NASA Tech Briefs, Vol. 30, No. 6 (June 2006), page 28. These sensors are wirelessly powered and interrogated, and the measurement acquisition system and sensors are extremely lightweight.The response recorder uses oscillating magnetic fields to power the sensors. Once powered, the sensors respond with their own magnetic field. For displacement/ rotation measurements, the response recorder uses the sensor s response amplitude, which is dependent on the distance from the antenna. The recorder s antenna orientation and position are kept fixed, and the sampling period is constant.

Woodard, Stanley E.; Taylor, Bryant D.

2007-01-01

399

Tunnel monitoring using multicore fibre displacement sensor  

NASA Astrophysics Data System (ADS)

In this paper, we report the first demonstration of multiplexed fibre Bragg grating strain sensors in a multicore fibre for shape measurement and their application to structural monitoring. Sets of gratings, acting as strain gauges, are co-located in the multicore fibre such that they enable the curvature to be determined via differential strain measurement. Multiple sets of these gratings allow the curvature to be measured at several points along the fibre. In this paper, the multicore fibre is configured to measure the deflection of a simple mechanical beam arising from the displacement of concrete tunnel sections. Laboratory tests are presented in which the system was demonstrated capable of displacement measurement with a resolution of ±0.1 mm over a range of several millimetres.

MacPherson, W. N.; Silva-Lopez, M.; Barton, J. S.; Moore, A. J.; Jones, J. D. C.; Zhao, D.; Zhang, L.; Bennion, I.; Metje, N.; Chapman, D. N.; Rogers, C. D. F.

2006-05-01

400

Computing Fault Displacements from Surface Deformations  

NASA Technical Reports Server (NTRS)

Simplex is a computer program that calculates locations and displacements of subterranean faults from data on Earth-surface deformations. The calculation involves inversion of a forward model (given a point source representing a fault, a forward model calculates the surface deformations) for displacements, and strains caused by a fault located in isotropic, elastic half-space. The inversion involves the use of nonlinear, multiparameter estimation techniques. The input surface-deformation data can be in multiple formats, with absolute or differential positioning. The input data can be derived from multiple sources, including interferometric synthetic-aperture radar, the Global Positioning System, and strain meters. Parameters can be constrained or free. Estimates can be calculated for single or multiple faults. Estimates of parameters are accompanied by reports of their covariances and uncertainties. Simplex has been tested extensively against forward models and against other means of inverting geodetic data and seismic observations. This work

Lyzenga, Gregory; Parker, Jay; Donnellan, Andrea; Panero, Wendy

2006-01-01

401

Charge-displacement analysis for excited states  

NASA Astrophysics Data System (ADS)

We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place.

Ronca, Enrico; Pastore, Mariachiara; Belpassi, Leonardo; De Angelis, Filippo; Angeli, Celestino; Cimiraglia, Renzo; Tarantelli, Francesco

2014-02-01

402

Charge-displacement analysis for excited states.  

PubMed

We extend the Charge-Displacement (CD) analysis, already successfully employed to describe the nature of intermolecular interactions [L. Belpassi et al., J. Am. Chem. Soc. 132, 13046 (2010)] and various types of controversial chemical bonds [L. Belpassi et al., J. Am. Chem. Soc. 130, 1048 (2008); N. Salvi et al., Chem. Eur. J. 16, 7231 (2010)], to study the charge fluxes accompanying electron excitations, and in particular the all-important charge-transfer (CT) phenomena. We demonstrate the usefulness of the new approach through applications to exemplary excitations in a series of molecules, encompassing various typical situations from valence, to Rydberg, to CT excitations. The CD functions defined along various spatial directions provide a detailed and insightful quantitative picture of the electron displacements taking place. PMID:24511925

Ronca, Enrico; Pastore, Mariachiara; Belpassi, Leonardo; De Angelis, Filippo; Angeli, Celestino; Cimiraglia, Renzo; Tarantelli, Francesco

2014-02-01

403

Laser displacement meter application for milling diagnostics  

NASA Astrophysics Data System (ADS)

This paper presents the application of a laser displacement meter for direct multi-purpose sensing of milling tool conditions. Using a laser displacement meter, a laser beam is projected onto the cutting tool and subsequently reflected. The intensity as well as the angle of the reflected beam are measured. The signals are interpreted for identification of tool geometry, tool whirling, or vibration. Signal processing and analysis depend on the application. A prototype system has been developed to demonstrate the feasibility of various applications, namely (1) tool setting evaluation, (2) in-process measurement of milling cutter geometry and detection of tool failure, (3) continuous monitoring of milling cutter deterioration, (4) detection and measurement of chatter in milling, (5) measurement of milling tool bending and (6) thermal expansion.

Ryabov, Oleg; Mori, Kazuo; Kasashima, Nagayoshi

1998-09-01

404

Atomic Mobile  

NSDL National Science Digital Library

Learners make a mobile model of a carbon atom using clay, wire, and pipe cleaners. Learners will use the periodic table as a guide and explore how atoms are made up of a nucleus of protons and neutrons with orbiting electrons. The activity includes a PDF file of a periodic table and a guide for reading it.

History, American M.

2012-06-26

405

Atomic supersymmetry  

NASA Technical Reports Server (NTRS)

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.

Kostelecky, V. Alan

1993-01-01

406

Displacement-sensitive organic field effect transistor  

Microsoft Academic Search

Thin films of organic semiconductor copper phthalocynanine (CuPc) and Al were deposited in sequence by vacuum evaporation on a glass substrate with Ag source and drain electrodes. The effect of displacement on the properties of the fabricated field effect transistor with metal (aluminium)–semiconductor (copper phthalocyanine) Schottky junction was investigated. It was observed that the drain–source resistance of this organic field

Kh. S. Karimov; M. Saleem; M. Mahroof-Tahir; T. A. Qasuria; Adam Khan; T. A. Khan

2011-01-01

407

Displacement-sensitive organic field effect transistor  

Microsoft Academic Search

Thin films of organic semiconductor copper phthalocynanine (CuPc) and Al were deposited in sequence by vacuum evaporation on a glass substrate with Ag source and drain electrodes. The effect of displacement on the properties of the fabricated field effect transistor with metal (aluminium)–semiconductor (copper phthalocyanine) Schottky junction was investigated. It was observed that the drain–source resistance of this organic field

Kh. S. Karimov; M. Saleem; M. Mahroof-Tahir; T. A. Qasuria; Adam Khan; T. A. Khan

2012-01-01

408

Uniform displacement mode for spherical systems  

NASA Astrophysics Data System (ADS)

The paper studies a time-independent displacement mode which is an exact solution of Vlasov-Poisson equation for spherical stellar systems and it is shown that it corresponds to an aspherical mode. Bartholomew formalism is used to write it explicitly to the second order and its generating function is given. For this marginal mode it is shown that the second variation of energy delta W vanishes.

Gillon, D.

1981-06-01

409

Suppression of displacement in severely slowed saccades  

Microsoft Academic Search

Severely slowed saccades in Spinocerebellar ataxia have previously been shown to be at least partially closed-loop in nature, their long duration means that they can be modified in-flight in response to intrasaccadic target movements. In this study, a woman with these pathologically slowed saccades could modify them in-flight in response to target movements, even when saccadic suppression of displacement (SSD)

Michael R. MacAskill; Tim J. Anderson; Richard D. Jones

2000-01-01

410

Optimization of a ferromagnetic displacement sensor  

Microsoft Academic Search

The paper presents and analysis a displacement ferromagnetic sensor. The analysis is carried out in order to optimize constructive and material parameters of the sensor. The described sensor is made of a magnetic ring core flux-gate and a permanent magnet. The flux-gate works in a self saturating push-pull magnetic circuit with half-wave rectification and is controlled by means of the

C. G. Haba; P. Haba; C. Cîrstea; V. M. Cosma; M. Lozovan

1997-01-01

411

Displaced-Phase-Center Antenna Technique  

Microsoft Academic Search

This article describes Lincoln Laboratory contributions to the development of the displaced-phase-center antenna (DPCA) technique, which was used to improve the detection performance of airborne or space-borne MTI radars that are subject to clutter. In the 1950s the DPCA technique was applied to airborne early warning (AEW) radars for defense of North America against long-range bombers carrying nuclear weapons. Lincoln

Charles Edward Muehe; Melvin Labitt

2000-01-01

412

Comparing Teaching Approaches About Maxwell's Displacement Current  

NASA Astrophysics Data System (ADS)

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.

Karam, Ricardo; Coimbra, Debora; Pietrocola, Maurício

2013-07-01

413

Simultaneous muscle force and displacement transducer  

NASA Technical Reports Server (NTRS)

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.

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

1980-01-01

414

Displacement measurement with over-determined interferometer  

NASA Astrophysics Data System (ADS)

We present a concept combining traditional displacement incremental interferometry with a tracking refractometer following the fluctuations of the refractive index of air. This concept is represented by an interferometric system of three Michelson-type interferometers where two are arranged in a counter-measuring configuration and the third one is set to measure the changes of the fixed length, here the measuring range of the overall displacement. In this configuration the two counter-measuring interferometers have identical beam paths with proportional parts of the overall one. The fixed interferometer with its geometrical length of the measuring beam linked to a mechanical reference made of a high thermal-stability material (Zerodur) operates as a tracking refractometer monitoring the atmospheric refractive index directly in the beam path of the displacement measuring interferometers. This principle has been demonstrated experimentally through a set of measurements in a temperature controlled environment under slowly changing refractive index of air in comparison with its indirect measurement through Edlen formula. With locking of the laser optical frequency to fixed value of the overall optical length the concept can operate as an interferometric system with compensation of the fluctuations of the refractive index of air.

Lazar, Josef; Holá, Miroslava; Hrabina, Jan; Buchta, Zden?k.; ?íp, Ond?ej; Oulehla, Jind?ich

2012-01-01

415

YUP.SCX: Coaxing Atomic Models into Medium Resolution Electron Density Maps  

PubMed Central

The structures of large macromolecular complexes in different functional states can be determined by cryo-electron microscopy, which yields electron density maps of low to intermediate resolutions. The maps can be combined with high-resolution atomic structures of components of the complex, to produce a model for the complex that is more accurate than the formal resolution of the map. To this end, methods have been developed to dock atomic models into density maps rigidly or flexibly, and to refine a docked model so as to optimize the fit of the atomic model into the map. We have developed a new refinement method called YUP.SCX. The electron density map is converted into a component of the potential energy function to which terms for stereochemical restraints and volume exclusion are added. The potential energy function is then minimized (using simulated annealing) to yield a stereochemically-restrained atomic structure that fits into the electron density map optimally. We used this procedure to construct an atomic model of the 70S ribosome in the pre-accommodation state. Although some atoms are displaced by as much as 33 Å, they divide themselves into nearly rigid fragments along natural boundaries with smooth transitions between the fragments.

Tan, Robert K.-Z.; Devkota, Batsal; Harvey, Stephen C.

2008-01-01

416

First-principles calculation of atomic force in the LSDA+U formalism  

NASA Astrophysics Data System (ADS)

We derive a formula for the atomic force within the LSDA+U formalism by differentiating analytically the LSDA+U total-energy functional with respect to atomic positions. The rotationally invariant form of the LSDA+U functional and the fully localized limit for the double-counting term are considered. The electronic wave functions are expanded with either plane waves or pseudoatomic orbitals (PAOs). In the PAO-basis case, the Pulay correction is also considered and included. Our formula for the atomic force is numerically tested with antiferromagnetic bulk NiO and reproduces successfully the forces obtained from numerical derivative of the total-energy values with respect to atomic displacements. As an application, we study atomic vibrations in NiO and MnO, and obtain transverse-optic phonon frequencies which are consistent with previous theoretical results. Our force formula will make it very efficient to perform large-scale calculations of atomic and phononic structures of strongly correlated materials using the LSDA+U method.

Park, Se Young; Choi, Hyoung Joon

2009-10-01

417

An integrated relative displacement self-sensing magnetorheological damper: prototyping and testing  

NASA Astrophysics Data System (ADS)

In this paper, an integrated relative displacement self-sensing magnetorheological damper (IRDSMRD) and the corresponding electronic system to realize the integrated relative displacement sensing and controllable damping, including the relative displacement modulator/demodulator, circuit for superposing the carrier signal for the integrated relative displacement sensor (IRDS) on the exciting current from the controllable current driver for the controllable damping and controllable current driver are developed and tested. In the developed IRDSMRD, the exciting coil is energized by the current from the controllable current driver, on which the carrier signal for the IRDS is superposed by the superposition circuit. The amplitude modulation of the carrier signal for the IRDS by the relative displacement between the piston and cylinder of the IRDSMRD and the magnetization of the MR fluid are realized through the frequency division multiplexing of the exciting coil for both the IRDS and the MR damper and the relative displacement is accessed by demodulating the induced harmonic voltage from the induction coil of the IRDSMRD by the demodulator. The characteristics of the developed IRDSMRD, including the linearity, sensitivity and hysteresis error of the IRDS and the controllable damping force are tested on the established experimental setup based on the MTS 849 shock absorber test system and the real time simulation system. The testing results indicate that the developed IRDSMRD can not only achieve the integration of the relative displacement sensing capability but also possesses good performance of the relative displacement sensing of the IRDS and the large controllable damping force range. In addition, the performance of the IRDS will not be affected by the exciting current within a certain range and the damping force will not be degraded by the carrier signal for the IRDS. The realized principle and technology of the IRDSMRD lay a foundation for reducing the commercializing cost of MR dampers.

Wang, D. H.; Bai, X. X.; Liao, W. H.

2010-10-01

418

Displacement along the Red River Fault constrained by extension estimates and plate reconstructions  

NASA Astrophysics Data System (ADS)

Significant E-W extension and/or compression must have been generated by displacements along the Red River Fault (RRF) since its curvature does not match a small circle centered at the Euler pole for the Indochina-south China plate pair. The amount of extension perpendicular to the RRF offshore Vietnam depends on the magnitude of left-lateral displacement along the RRF. In general, the larger the left-lateral displacement along the fault, the smaller the amount of E-W extension. All purely strike-slip models of the opening of the South China Sea that assume large displacements (>250 km) along the RRF encounter major problems because they imply little extension, or even considerable shortening, offshore east Vietnam. This is inconsistent with the presence of large elongated basins offshore Vietnam. Using a plate tectonic model, we compare continental extension values implied by different magnitudes of displacement along the RRF with crustal stretching estimates derived from 2-D profiles modeled from gravity data. We utilize 2-D gravity forward models to restore the extended continental margin crust to its original position prior to extension. We find that substantial amounts of extension for offshore Vietnam can only be modeled assuming moderate displacements along the RRF compatible with the presence of a southward subducting proto-South China Sea. The total amount of ENE-WSW extension offshore northern Vietnam constrained by our 2-D gravity profiles and gravity inversion increases southward from 36 to 89 km along the Yinggehai Basin. These values of ENE-WSW extension are consistent with 250 km of left-lateral displacement along the RRF.

Mazur, S.; Green, C.; Stewart, M. G.; Whittaker, J. M.; Williams, S.; Bouatmani, R.

2012-10-01

419

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

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Engine displacement, motorcycle classes. 86.419-78 Section...Regulations for 1978 and Later New Motorcycles, General Provisions § 86.419-78 Engine displacement, motorcycle classes. (a)(1)...

2013-07-01

420

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

Code of Federal Regulations, 2013 CFR

... false Engine displacement, motorcycle classes. 86.419-2006 Section...Regulations for 1978 and Later New Motorcycles, General Provisions § 86.419-2006 Engine displacement, motorcycle classes. (a)(1)...

2013-07-01

421

Gas Miscible Displacement Enhanced Oil Recovery. Technology Status Report.  

National Technical Information Service (NTIS)

Research on gas flooding and miscible displacement, with an emphasis on improvement of CO2 flood performance is described. Low reservoir volumetric sweep efficiency is the major problem associated with gas flooding and all miscible displacements. CO2 floo...

R. J. Watts C. A. Komar

1989-01-01

422

Anharmonic Thermal Motion of Atoms in Thermoelectric Mg2Si Studied via Convergent-beam Electron Diffraction  

SciTech Connect

We study the thermal motion of the atoms in the thermoelectric material Mg{sub 2}Si by using electron diffraction. The nanodiffraction or convergent-beam electron diffraction technique we use allows us to observe simultaneously many Bragg reflections with large reciprocal lattice vectors. Previous observations of anharmonicity by single-crystal x-ray diffraction are confirmed, and we determine the anharmonicity parameter of the Mg atom in the tetrahedral environment with high accuracy, {beta} = (-4.27 {+-} 0.14) x 10{sup -12} erg {angstrom}{sup -3} around room temperature. In an alternative picture the Mg atom tends to vibrate around positions displaced 4.50 {+-} 0.14 pm from the center of the tetrahedron.

Valset K.; Wu L.; Taft, J.; Zhu, Y.

2011-12-01

423

Nonlinear strain-displacement relations and flexible multibody dynamics  

NASA Technical Reports Server (NTRS)

Dynamics of chains of flexible bodies undergoing large rigid body motions, but small elastic deflections are considered. The role of nonlinear strain-displacement relations in the development of the motion equations correct to first order in elastic deflections is investigated. The general form of these equations linearized only in the small elastic deflections is presented, and the relative significance of various nonlinear terms is studied both analytically and through the use of the numerical simulations. Numerical simulations are performed for a two link chain constrained to move in the plane, subject to hinge torques. Each link is modeled as a thin beam. Slew maneuver simulation results are compared for models with and without properly modeled kinematics of deformation. The goal of this case study is to quantify the importance of the terms in the equations of motion which arise from the inclusion of nonlinear strain-displacement relations. It is concluded that unless the consistently linearized equations in elastic deflections and speeds are available and necessary, the inconsistently (prematurely) linearized equations should be replaced in all cases by ruthlessly linearized equations: equations in which all nonlinear terms involving the elastic deflections and speeds are ignored.

Padilla, Carlos E.; Vonflotow, Andreas H.

1989-01-01

424

Interseismic Displacements: Cycle Invariance, Slip Rate, and Rheology  

NASA Astrophysics Data System (ADS)

Geodetic data are commonly interpreted in terms of strain accumulation on faults. Often such interpretations are guided by simple models of interseismic displacements near an infinite strike slip fault (e.g. Savage and Prescott, 1978). These models assume relatively simple rheologies and that the system is in a cycle invariant state, with periodic ruptures such that the displacements throughout the seismic cycle do not vary from one cycle to the next. The displacements are given by perturbations to an average arctangent displacement profile, parameterized by the slip rate and locking depth of the fault. We explore the relationship between cycle invariance, changes in slip rate, and rheology to inferences of slip rate, locking depth, and rheology in models of infinite faults with given histories and sizes of ruptures. The number of seismic cycles required to attain cycle invariance is a function of the strength of the system (parameterized by the Maxwell relaxation time, ? M) and the recurrence time of the ruptures (period, T). In systems with ? M << T the invariant average arctangent curve is established over very few seismic cycles. However, for ? M ? T or ? M > T, it takes many seismic cycles to establish cycle invariance. A consequence of this is that it is easy to confuse a large postseismic relaxation signal (low ? M) calculated ignoring all but the latest earthquake with a periodic system and a small post-seismic relaxation signal (high ? M). During transition to cycle invariance, the average stress level of the system changes by an amount ? ? , determined by ? M, T, and the stress drop in a rupture (? eq); ? ? is independent of the magnitude of the initial background stress. For low ? M, ? ? is negligible compared to ? eq, but may be much larger than ? eq for high ? M. A change in slip rate on a fault, accommodated by a change in recurrence time or ? eq, tends to force the system toward a new average stress. For weak rheologies, changes in slip rate are negligible as the system establishes cycle invariance quickly. However, for stronger rheologies, it takes many seismic cycles to attain cycle invariance, and during the non-invariant transitional time, inferences of slip rate, locking depth, and rheology will be incorrect.

Hetland, E. A.; Hager, B. H.

2003-12-01

425

Atomic gravitational wave interferometric sensor  

Microsoft Academic Search

We propose two distinct atom interferometer gravitational wave detectors, one\\u000aterrestrial and another satellite-based, utilizing the core technology of the\\u000aStanford 10 m atom interferometer presently under construction. Each\\u000aconfiguration compares two widely separated atom interferometers run using\\u000acommon lasers. The signal scales with the distance between the interferometers,\\u000awhich can be large since only the light travels over this

Savas Dimopoulos; Peter W. Graham; Jason M. Hogan; Mark A. Kasevich; Surjeet Rajendran

2008-01-01

426

Acting Atoms.  

ERIC Educational Resources Information Center

Describes a fun game in which students act as electrons, protons, and neutrons. This activity is designed to help students develop a concrete understanding of the abstract concept of atomic structure. (DKM)

Farin, Susan Archie

1997-01-01

427

Kinetic Atom.  

ERIC Educational Resources Information Center

Surveys the research of scientists like Joule, Kelvin, Maxwell, Clausius, and Boltzmann as it comments on the basic conceptual issues involved in the development of a more precise kinetic theory and the idea of a kinetic atom. (Author/SK)

Wilson, David B.

1981-01-01

428

Secondary atomization  

Microsoft Academic Search

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

D. R. Guildenbecher; C. López-Rivera; P. E. Sojka

2009-01-01

429

Stability of Miscible Displacements Across Stratified Porous Media  

SciTech Connect

This report studied macro-scale heterogeneity effects. Reflecting on their importance, current simulation practices of flow and displacement in porous media were invariably based on heterogeneous permeability fields. Here, it was focused on a specific aspect of such problems, namely the stability of miscible displacements in stratified porous media, where the displacement is perpendicular to the direction of stratification.

Shariati, Maryam; Yortsos, Yanis C.

2000-09-11

430

Displaced Homemaker Program: 1997-1999 Biennial Report.  

ERIC Educational Resources Information Center

The Washington State Displaced Homemaker Program (DHP) as administered by the Higher Education Coordinating Board (HECB) accomplished its goals during the 1997-99 biennium. Four multipurpose service centers provided services to displaced homemakers in urban and rural county areas; four programs provided services to displaced homemakers in rural…

Washington State Higher Education Coordinating Board, Olympia.

431

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

ERIC Educational Resources Information Center

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…

Grindon, Leger

1989-01-01

432

Miscible fluid displacement stability in unconfined porous media  

Microsoft Academic Search

In situ flushing groundwater remediation technologies, such as cosolvent flushing, rely on the stability of the interface between the resident and displacing fluids for efficient removal of contaminants. Contrasts in density and viscosity between the resident and displacing fluids can adversely affect the stability of the displacement front. Petroleum engineers have developed techniques to describe these types of processes; however,

James W. Jawitz; Michael D. Annable; P. S. C. Rao

1998-01-01

433

Estimation of Displacement Location for Enhanced Strain Imaging  

Microsoft Academic Search

Ultrasonic strain imaging usually begins with displacement estimates computed using finite-length sections of RF ultrasound signals. Amplitude variations in the ultrasound are known to perturb the location at which the displacement estimate is valid. If this goes uncorrected, it is a significant source of estimation noise, which is amplified when displacement fields are converted into strain images. We present a

Joel E. Lindop; Graham M. Treece; Andrew H. Gee; Richard W. Prager

2007-01-01

434

Induction Machine Analysis for Arbitrary Displacement Between Multiple Winding Sets  

Microsoft Academic Search

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

R. H. Nelson; P. C. Krause

1974-01-01

435

USING A DISPLACEMENT-BASED APPROACH FOR EARTHQUAKE LOSS ESTIMATION  

Microsoft Academic Search

A displacement-based earthquake loss assessment procedure currently under development is presented. Predictions of the degree of damage to buildings under both ground shaking and liquefaction-induced ground failure can be carried out with this method. Earthquake actions and structural reactions are represented by displacements following the observed correlation between building damage and lateral displacements. The main concept is to compare the

JULIAN J. BOMMER; RUI PINHO; HELEN CROWLEY

436

Load-Displacement Measurement on Pin-Loaded Specimens  

NASA Technical Reports Server (NTRS)

Tubes apply as displacement is registered by long armed, double-cantilever gage. Sharp points at ends of arms protrude through holes in tube walls and contact center of area of load applications. Method was devised for determining load point displacement accurately. No extraneous displacement fraction is present in measurement, and data-correction procedures are unnecessary.

Fisher, D. M.; Buzzard, R.

1982-01-01

437

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

ERIC Educational Resources Information Center

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…

Lindo, Jason M.

2010-01-01

438

Are Displaced Miogeoclinal Rocks present in metamorphic pendants in the central and southern Sierra Nevada  

Microsoft Academic Search

In high flux arcs regional tectonic events are largely preserved in small host rock pendants. It has been proposed in the Sierran arc, California that a block of passive margin sediments (Snow Lake block) has been displaced to its present location from an uncertain origin. Members of the USC undergraduate team research program have studied two pendants, the Boyden Cave

L. B. Gelbach; J. Chang; E. van Guilder; S. R. Paterson; V. Memeti

2009-01-01

439

Perceived risk, displacement and refuging in brown bears: positive impacts of ecotourism?  

Microsoft Academic Search

Ecotourism is a rapidly growing industry with unknown impacts on viewed wildlife that may require novel management action. We examined the impact of viewing activities on the behaviour of brown bears (Ursus arctos) in coastal British Columbia.Domination of the best feeding sites and human avoidance by large male bears has consistently been reported. We, however, saw displacement in time rather

Owen T. Nevin; Barrie K. Gilbert

2005-01-01

440

Finite element analysis of buried steel pipelines under strike-slip fault displacements  

Microsoft Academic Search

The present paper investigates the mechanical behavior of buried steel pipelines, crossing an active strike-slip tectonic fault. The fault is normal to the pipeline direction and moves in the horizontal direction, causing stress and deformation in the pipeline. The interacting soil–pipeline system is modelled rigorously through finite elements, which account for large strains and displacements, nonlinear material behavior and special

Polynikis Vazouras; Spyros A. Karamanos; Panos Dakoulas

2010-01-01

441

Direct evidence for atomic defects in graphene layers  

Microsoft Academic Search

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

Ayako Hashimoto; Kazu