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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

Frictional behavior of large displacement experimental faults  

USGS Publications Warehouse

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

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

1996-01-01

4

Large displacement analysis of a marine riser  

SciTech Connect

A method of static analysis for a marine riser experiencing large displacements is presented. The method is suitable for analyzing a riser having a known top tension and a possible slippage at the top slip joint. Utilizing the stationary condition of a functional coupled with an equilibrium equation, one can conveniently obtain the equilibrium configuration numerically. The configuration is expressed in terms of the rectangular coordinates. The functional representing the energy and work of the riser system is expressed in terms of the horizontal coordinate which is parameterized in terms of the vertical depth instead of arc length. For a twodimensional problem, two multipliers must be included in the functional. One of the two represents the variable axial force along the length of the riser and the other corresponds to the strain energy per unit riser length due to bending. Utilizing the finite element method, a numerical procedure to obtain the configuration of static equilibrium is given. The resulting algebraic equations are highly nonlinear and the Newton-Raphson iterative procedure is used to solve the equations. An example is given.

Huang, T.; Chucheepsakul, S.

1985-03-01

5

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

6

Frictional behavior of large displacement experimental faults  

Microsoft Academic Search

The coefficient of friction and velocity dependence of friction of initially bare surfaces and 1-mm-thick simulated fault gouges (< 90 gm) of Westerly granite were determined as a func- tion of displacement to >400 mm at 25øC and 25 MPa normal stress. Steady state negative friction velocity dependence and a steady state fault zone microstructure are achieved after --18 mm

N. M. Beeler; T. E. Tullis; M. L. Blanpied

1996-01-01

7

Intrinsic Noise Properties of Atomic Point Contact Displacement Detectors  

NASA Astrophysics Data System (ADS)

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 random thermal motion of the beam at 250 mK. We demonstrate a shot-noise limited imprecision of 2.3fm/Hz and observe a 78aN/Hz backaction force, yielding a total uncertainty in the beam’s displacement that is 42 times the standard-quantum limit.

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

2007-03-01

8

Static displacements of atoms in crystalline metallic solid solutions  

NASA Astrophysics Data System (ADS)

Measurement of diffuse x-ray scattering from binary crystalline solid solutions at more than one x-ray energy is a sensitive probe of the average interatomic distance between neighboring pairs of atoms. Deviations of these bond distances by as little as 0.001 (angstrom) are easily detected in the diffuse scattering from binary alloys consisting of atoms nearby in the periodic table and/or where x-ray energies chosen near their absorption edges can change the scattering contrast. Individual bond distances (AA, AB and BB) are recovered out to several near neighbor shells by combining three scattering measurements at x-ray energies chosen for maximum and minimum contrast. Average bond distances recovered from four metal alloys Fe(77.5)Ni(22.5), Fe(46.5)Ni(53.5), Cr(47)Fe(53) and Cr(20)Ni(80) are discussed. The authors find that the interatomic distances measured for these alloys give interesting insights to atomic displacements in solid solutions. Nearest neighbor bond distances are not well represented by phenomenological models based on pure element atomic size and concentration dependence of the lattice constants. Radial and nonradial displacements are recovered from these measurements of diffuse scattering.

Sparks, C.; Ice, G.; Jiang, X.; Zschack, P.

9

A large displacement formulation for anisotropic constitutive laws  

Microsoft Academic Search

This work has been motivated by configurations designed in our laboratory for which wood samples undergo large displacements that result in more accurate measurements.From a theoretical point of view, such configurations require a formulation able to take into account the geometrical non-linearities in the case of a highly anisotropic material. This paper proposes a solution to this specific problem in

B. Mauget; P. Perré

1999-01-01

10

Large displacement vertical translational actuator based on piezoelectric thin films  

NASA Astrophysics Data System (ADS)

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

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

2010-07-01

11

Large displacement of a static bending nanowire with surface effects  

NASA Astrophysics Data System (ADS)

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

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

2012-07-01

12

Elastic instability of crystals caused by static atom displacement: A mechanism for solid-state amorphization  

NASA Astrophysics Data System (ADS)

During the solid-state amorphization process, there have been a number of observations showing a large lattice dilatation and softening of shear elastic constants. Based on these reports, the amorphization mechanism was modeled by introducing static displacement of atoms that caused lattice strain. The calculation indicated that a crystalline structure became unstable at a critical strain value. Qualitative agreement was obtained between the calculated and experimental values of the changes in the shear elastic constant and the lattice parameter at the instability point.

Koike, J.

1993-04-01

13

Macroscopic superposition and entanglement for displaced thermal fields induced by a single atom  

Microsoft Academic Search

We show that a cavity field can evolve from an initial displaced mixed thermal state to a macroscopic superpositions of displaced thermal states via resonant interaction with a two-level atom. As a macroscopic system (meter) is really in a mixed state before coupling with the microscopic system at some temperature, our result is important for studying the quantum measurement problem

Shi-Biao Zheng

2007-01-01

14

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

Microsoft Academic Search

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

J. H. Argyris

1965-01-01

15

High-resolution electron-microscope images of crystals with correlated atomic displacements.  

PubMed

A coordinate-space multislice description of the scattering of high-energy electrons is constructed from consecutions of differential operators acting upon atomic potentials. It is used to find expressions for the intensity distribution in high-resolution electron-microscope images of crystals whose atoms are periodically displaced relative to a reference lattice according to a modulation wave. Both static correlated displacements, such as occur in modulated structures, and time-dependent correlated displacements, as are generated by phonons, are considered. Two aspects of the image are examined in detail; its translational symmetry and its dependence upon the correlations between the atomic displacements. It is shown that the intensity distribution due to scattering from static correlated displacements has the translational symmetry of the modulated structure in that projection, as determined by the component of the modulation wavevector perpendicular to the incident beam, whereas that due to scattering from phonons has the translational symmetry of the reference lattice in that projection. The former is a consequence of higher-order Laue-zone interactions. The intensity distribution due to scattering from static displacements depends upon the absolute phase of the displacement at each scattering atomic site whereas that due to scattering from phonons depends only upon the relative phase of the displacements between different scattering sites, both within the same atomic column parallel to the beam and in adjacent columns. In both cases, the influence of the component of the correlation wavevector parallel to the incident beam is different to that perpendicular to the beam; the former affects the intensity mostly at the atomic sites whilst the latter affects the intensity mostly between the atomic sites. It is also observed that, as a consequence of the periodic nature of the polarization-vector function, the interference terms are small, both relative to the non-interference term and in an absolute sense, particularly for phonon scattering. For this reason, the contribution to the image due to scattering from correlated atomic displacements will have greater and sharper atomic contrast than that due to scattering from the reference structure without displacements. In addition, this component of the intensity distribution will not exhibit strong contrast reversal when the objective-lens defocus is changed. PMID:10927244

Etheridge

1999-03-01

16

Quantitative Local Atomic Displacements from Huang Scattering Normalized by Thermal Diffuse Scattering  

NASA Astrophysics Data System (ADS)

The three-dimensional (3-D) pattern of atomic displacements at the core of a small defect or defect cluster embedded in a bulk crystal is possible to measure in principle, but difficult to obtain in practice, especially if quantitative displacements are desired. Here, it is demonstrated that a least-squares fit to the single-crystal X-ray Huang-scattering distribution surrounding an intense Bragg peak is a practical means of obtaining quantitative displacements when thermal diffuse scattering is used as an internal intensity standard. After fitting a model based on local Kanzaki forces embedded within an elastic continuum, the use of finite-defect and point-defect methods of computing and interpreting the pattern of local displacements are compared and contrasted. To make the analysis general with regard to both crystal symmetry and defect symmetry, numerical Fourier transforms are employed rather than pursuing analytical expressions for the displacements.

Campbell, Branton J.

2010-05-01

17

Atomic force microscope cantilevers as encoders for real-time forward and backward displacement measurements  

NASA Astrophysics Data System (ADS)

Atomic force microscope cantilevers have been investigated for their use as the encoder for real-time high-resolution displacement measurements, when paired with a 1D sinusoidal grating of well-known pitch. For a known one-directional (forward or backward) displacement measurement, the decoding algorithm is based on directly counting the integer periods of the grating and calculating the fractional parts at the beginning of the displacement and at the actual position by using one cantilever. Using two cantilevers arranged in the quadrature phase shift positions on the grating makes the measurement of two-directional (forward and backward) displacements possible. The decoding algorithm directly unwraps the phase between two encoded signals. Cross-correlation filtering and the differentiation process of two encoded signals are found to be very successful to guarantee the implementation of real-time displacement measurements by suppressing noise and reducing the offset and tilt of the encoded signals.

Chen, Xiaomei; Koenders, Ludger; Wolff, Helmut; Neddermeyer, Holger; Haertig, Frank

2011-09-01

18

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

19

Macroscopic superposition and entanglement for displaced thermal fields induced by a single atom  

SciTech Connect

We show that a cavity field can evolve from an initial displaced mixed thermal state to a macroscopic superpositions of displaced thermal states via resonant interaction with a two-level atom. As a macroscopic system (meter) is really in a mixed state before coupling with the microscopic system at some temperature, our result is important for studying the quantum measurement problem and decoherence under real conditions. For the two-mode case, entanglement of displaced thermal states between the modes can be obtained.

Zheng, Shi-Biao [Department of Electronic Science and Applied Physics, Fuzhou University, Fuzhou 350002 (China)

2007-03-15

20

A Continuous Formulation of the Cluster Variation Method for Atomic Displacements  

Microsoft Academic Search

We present a continuous formulation of the CVM for lattice site displacements. The basic idea is to restrict the density probability functions to Gaussians. This leads to a very simple free energy functional whose variational parameters are the covariances between the atomic coordinates.

Alphonse Finel

1994-01-01

21

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

22

Static atomic displacements in Cu&barbelow;-Mn measured with diffuse x-ray scattering  

NASA Astrophysics Data System (ADS)

Diffuse x-ray scattering of a Cu- 17.2at.% Mn single crystal, which was aged at 483 K for 2 weeks, was taken at three energies, namely, 6526, 8969, and 8909 eV, which were suited for an evaluation by the 3? technique. The values of the species-dependent static atomic displacements closely agree with those of a Georgopoulos-Cohen evaluation, which also uses the three data sets. Nearest-neighbor displacements are dominant and with ˜0.038Å largest among Cu-Mn pairs. A tendency is noted for lattice expansion between those elements (equal or unequal pairs) that are preferred in site occupancy over a random arrangement because of local atomic order.

Schönfeld, B.; Roelofs, H.; Kostorz, G.; Robertson, J. L.; Zschack, P.; Ice, G. E.

2008-04-01

23

Atomic force microscope cantilever as an encoding sensor for real-time displacement measurement  

NASA Astrophysics Data System (ADS)

A tuning fork-based atomic force microscope cantilever has been investigated for application as an encoding sensor for real-time displacement measurement. The algorithm used to encode the displacement is based on the direct count of the integer pitches of a known grating, and the calculation of the fractional parts of a pitch at the beginning and during displacement. A cross-correlation technique has been adopted and applied to the real-time signal filtering process for the determination of the pitch during scanning by using a half sinusoidal waveform template. For the first investigation, a 1D sinusoidal grating with the pitch of 300 nm is used. The repeatability of displacement measurements over a distance of 70 µm is better than 2.2 nm. As the first application, the real-time displacement of a scanning stage is measured by the new encoding principle as it is moved in an open-loop mode and closed-loop mode based on its built-in capacitance sensor.

Chen, Xiaomei; Koenders, Ludger; Wolff, Helmut; Haertig, Frank; Schilling, Meinhard

2010-10-01

24

Membrane action of unrestrained lightly reinforced concrete slabs at large displacements  

Microsoft Academic Search

Following full-scale fire tests on a steel-framed building, together with observations from real fires, it has been shown that membrane action, at large displacements, of composite floors comprising steel deck, concrete, and anti-crack mesh, is extremely beneficial to the survival of the building. It was therefore decided to review previous research conducted on unrestrained concrete slabs, under large displacements, at

Colin G Bailey

2001-01-01

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

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

PubMed

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. PMID:17139089

Petrova, Tatiana; Ginell, Stephan; Mitschler, Andre; Hazemann, Isabelle; Schneider, Thomas; Cousido, Alexandra; Lunin, Vladimir Y; Joachimiak, Andrzej; Podjarny, Alberto

2006-11-23

27

Interaction-induced atomic displacements revealed by drift-corrected dynamic force spectroscopy  

NASA Astrophysics Data System (ADS)

The three-dimensional force field above an NaCl(001) surface was measured on a fine grid by small amplitude dynamic force spectroscopy at room temperature. After careful drift corrections, maps in nominally equivalent symmetry planes as well as in sections parallel to the surface reveal distance-dependent shifts of characteristic atomic-sized features. These shifts reflect asymmetries of the probing tip apex but are mainly due to atomic displacements induced by short-range forces. In addition, weak decaying force oscillations with a period close to the interlayer spacing are detected at distances where no atomic-scale variations are expected. Stronger site-dependent changes appear in the interaction-induced energy dissipation.

Kawai, Shigeki; Glatzel, Thilo; Koch, Sascha; Baratoff, Alexis; Meyer, Ernst

2011-01-01

28

Tracking planes with large interframe displacement by fusing template and point based approaches  

Microsoft Academic Search

This paper presents a hybrid approach by fusing template and keypoint based tracking to track pose of planar textured targets with large interframe displacement. The fusion is made such that it adds to accuracy and convergence of template based tracking. The approach is not only robust against illumination changes and partial occlusion, but also free from offline pose learning and

Naeem Akhter

2011-01-01

29

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

NASA Astrophysics Data System (ADS)

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 brick into large displacement of a translational platform. For ±120 V input, a full range of 486 µm of motion is achieved, with natural frequency greater than 500 Hz. This corresponds to the anticipated value found analytically and by simulation. 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.

2011-06-01

30

Atom probe tomography characterization of thin copper layers on aluminum deposited by galvanic displacement.  

PubMed

?Ultrathin? metallization layers on the order of nanometers in thickness are increasingly used in semiconductor interconnects and other nanostructures. Aqueous deposition methods are attractive methods to produce such layers due to their low cost, but formation of ultrathin layers has proven challenging, particularly on oxide-coated substrates. This work focused on the formation of thin copper layers on aluminum, by galvanic displacement from alkaline aqueous solutions. Analysis by atom probe tomography (APT) showed that continuous copper films of approximately 1 nm thickness were formed, apparently the first demonstration of deposition of ultrathin metal layers on oxidized substrates from aqueous solutions. The APT reconstructions indicate that deposited copper replaced a portion of the surface oxide film on aluminum. The results are consistent with mechanisms in which surface hydride species on aluminum mediate deposition, either by directly reducing cupric ions or by inducing electronic conduction in the oxide, thus enabling cupric ion reduction by Al metal. PMID:22220909

Zhang, Yi; Ai, Jiahe; Hillier, Andrew C; Hebert, Kurt R

2012-01-10

31

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

32

Experimental and numerical tools for miscible fluid displacements studies in porous media with large heterogeneities  

NASA Astrophysics Data System (ADS)

We present a set of complementary experimental and numerical tools for studying miscible fluid displacements in porous media with large scale heterogeneities. Experiments are realized in transparent 2D Hele-Shaw cells allowing optical observations and in 3D packings of glass beads with an acoustical technique for imaging fluid displacements. Permeability heterogeneities are modeled by spatial variations of either the local aperture of the Hele-Shaw cell or the diameter of the grains used in the packing. The Hele-Shaw cell model provides high resolution maps of the invasion front location at regular time intervals and of the flow lines: the velocity field is determined by combining these informations. Acoustical images of relative concentration distributions in the 3D packing are in agreement with Hele-Shaw cell data and can be obtained in a broader range of experimental situations. Such experiments realized with a stabilizing density contrast between invading and displaced fluids demonstrate a strong reduction of the front width at low flow velocities, a similar reduction is obtained at high velocities with a stabilizing viscosity contrast. The technique is also applicable to study fluid displacements in natural opaque media. Numerical simulations by a Boltzmann lattice technique using a Stokes-like diffusive term to smooth out the effect of permeability discontinuities provide complementary informations. They are shown to give similar results as experiments for same flow parameter values and to allow for a fast exploration of a broad range of fluid properties and flow situations.

Berest, P.; Rakotomalala, N.; Hulin, J. P.; Salin, D.

1999-06-01

33

Experimental and numerical tools for miscible fluid displacements studies in porous media with large heterogeneities  

NASA Astrophysics Data System (ADS)

We present a set of complementary experimental and numerical tools for studying miscible fluid displacements in porous media with large scale heterogeneities. Experiments are realized in transparent 2D Hele-Shaw cells allowing optical observations and in 3D packings of glass beads with an acoustical technique for imaging fluid displacements. Permeability heterogeneities are modeled by spatial variations of either the local aperture of the Hele-Shaw cell or the diameter of the grains used in the packing. The Hele-Shaw cell model provides high resolution maps of the invasion front location at regular time intervals and of the flow lines: the velocity field is determined by combining these informations. Acoustical images of relative concentration distributions in the 3D packing are in agreement with Hele-Shaw cell data and can be obtained in a broader range of experimental situations. Such experiments realized with a stabilizing density contrast between invading and displaced fluids demonstrate a strong reduction of the front width at low flow velocities, a similar reduction is obtained at high velocities with a stabilizing viscosity contrast. The technique is also applicable to study fluid displacements in natural opaque media. Numerical simulations by a Boltzmann lattice technique using a Stokes-like diffusive term to smooth out the effect of permeability discontinuities provide complementary informations. They are shown to give similar results as experiments for same flow parameter values and to allow for a fast exploration of a broad range of fluid properties and flow situations.

Berest, P.; Rakotomalala, N.; Hulin, J. P.; Salin, D.

1999-09-01

34

Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance Measurements: Interactions and Displacement Field of a Quartz Crystal Microbalance  

Microsoft Academic Search

We analyze the interaction of two instruments often used in material science analysis, the atomic force microscope (AFM) and the quartz crystal microbalance (QCM), here combined in a single instrument for simultaneous measurements on a single sample. We show, using finite element analysis, that the in-plane displacement of a QCM oscillating in liquid with a quality factor of 2000 is

J.-M. Friedt; K. H. Choi; L. Francis; A. Campitelli

2002-01-01

35

Calculated sputtering and atomic displacement cross-sections for applications to medium voltage analytical electron microscopy  

NASA Astrophysics Data System (ADS)

The development of medium voltage electron microscopes having high brightness electron sources and ultra-high vacuum environments has been anticipated by the microscopy community now for several years. The advantages of such a configuration have been discussed to great lengths, while the potential disadvantages have for the most part been neglected. The most detrimental of these relative to microcharacterization are the effects of electron sputtering and atomic displacement to the local specimen composition. These effects have in the past been considered mainly in the high voltage electron microscope regime and generally were ignored in lower voltage instruments. Recent experimental measurements have shown that the effects of electron sputtering as well as radiation induced segregation can be observed in conventional transmission electron microscopes. It is, therefore, important to determine at what point the effects will begin to manifest themselves in the new generation of medium voltage analytical electron microscopes. In this manuscript we present new calculations which allow the individual experimentalist to determine the potential threshold levels for a particular elemental system and thus avoid the dangers of introducing artifacts during microanalysis.

Bradley, C. R.; Zaluzec, N. J.

1987-08-01

36

Experiments on Methane Displacement by Carbon Dioxide in Large Coal Specimens  

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

37

A thermo-hydraulic wax actuation system for high force and large displacement applications  

NASA Astrophysics Data System (ADS)

An actuation system, making use of paraffin wax as a smart material, has been developed for high force, large displacement applications. Wax actuators exploit the significant volumetric expansion (typically between 10 and 15%) experienced during the solid to liquid phase change of paraffin wax. When contained, this expansion results in considerable hydrostatic pressure. Traditionally, wax actuators are designed such that the wax acts directly, via a compliant seal, on an output device such as a piston. We propose using an additional intermediate (passive) fluid to transmit pressure to a separate remote actuator. In essence, we propose a solid-state 'pump' for hydraulic actuation, with no moving parts and which requires no maintenance. The pump makes use of paraffin wax pellets, submerged in hydraulic fluid. The pellets are encapsulated in silicone rubber to prevent contamination of the hydraulic fluid. Upon melting, the volumetric expansion is used to displace the hydraulic working fluid, which is in turn used to drive a conventional hydraulic actuator. Making use of only 65g of paraffin wax, heated from room temperature to 80ºC, the pump generated a blocked pressure of 45MPa and displaced 15.7ml of hydraulic fluid. The pump was used to drive a commercial actuator, and achieved a free stroke of 24.4mm and a blocked force of approximately 29kN.

Long, Craig S.; Loveday, Philip W.

2007-04-01

38

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

PubMed

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

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

2013-10-30

39

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

40

Fuzzy clustering methods: An application to atomic displacement cascades in solids  

NASA Astrophysics Data System (ADS)

Representations based on the concepts of the theory of fuzzy sets are suggested to apply to a wide variety of problems in physics. A grade of membership is associated to each element in a set, which is a measure of its distance to a prototype. Fuzzy representations are thus adequate for dealing with situations where the belongingness of an object or a phenomenon to a class is uncertain, or to situations where the classes have no exact definition. An explicit relation is shown between fuzzy representation and dimensionality. Unambiguous definitions of the degree of fuzziness, cluster overlap, and isolated points are given on the basis of an anisotropic grade of membership function. The example is treated of collision cascades generated by xenon atoms incident on a polycrystalline gold surface with energies ranging from 20 keV to 1 MeV. The cascades are simulated in the binary collision approximation with the Marlowe computer code. They are shown to germinate from simultaneously growing collisions clusters. The displacement cascades are found to be only partially space filling. This is emphasized on the basis of their fuzzy geometrical characteristics, without need of any assumption concerning self-similarity. Their possible overlap and lumping are identified on the basis of the grade of membership of each vacated lattice site to each cluster. The final cluster pattern of the vacancy distributions is shown to depend on the degree of fuzziness. The sensitivity of several properties of vacancy clusters on the degree of fuzziness is discussed. This sensitivity is suggested to be a consequence of their granular structure. Consequently, their experimental characterization may be influenced by the resolution of the observation method. Fuzzy analysis is suggested as a tool to establish the relation between measures at different scales of the same phenomenon.

Hou, M.

1989-03-01

41

Simultaneous Atomic Force Microscope and Quartz Crystal Microbalance Measurements: Interactions and Displacement Field of a Quartz Crystal Microbalance  

NASA Astrophysics Data System (ADS)

We analyze the interaction of two instruments often used in material science analysis, the atomic force microscope (AFM) and the quartz crystal microbalance (QCM), here combined in a single instrument for simultaneous measurements on a single sample. We show, using finite element analysis, that the in-plane displacement of a QCM oscillating in liquid with a quality factor of 2000 is 2 nm. The out-of-plane displacement is about one tenth of the in-plane displacement. This latter effect, due to the finite size of the electrodes, results in longitudinal acoustic waves launched in the liquid surrounding the QCM. If bounced against an obstacle, in our case the AFM cantilever holder, these longitudinal waves create standing wave patterns which cause frequency fluctuations of the resonator when it is moved, and thus decrease the QCM sensitivity.

Friedt, J.-M.; Choi, K. H.; Francis, L.; Campitelli, A.

2002-06-01

42

Exploiting Universality in Atoms with Large Scattering Lengths  

SciTech Connect

The focus of this research project was atoms with scattering lengths that are large compared to the range of their interactions and which therefore exhibit universal behavior at sufficiently low energies. Recent dramatic advances in cooling atoms and in manipulating their scattering lengths have made this phenomenon of practical importance for controlling ultracold atoms and molecules. This research project was aimed at developing a systematically improvable method for calculating few-body observables for atoms with large scattering lengths starting from the universal results as a first approximation. Significant progress towards this goal was made during the five years of the project.

Braaten, Eric

2012-05-31

43

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

44

Static atomic displacements of Sn in disordered NiAs/Ni2In type HT-Ni1+?Sn  

NASA Astrophysics Data System (ADS)

The crystal structures of the intermediate solid solution HT (high temperature) Ni1+?Sn with ?=0.28, 0.52 and 0.61 (refined Ni contents) have been analyzed in detail by X-ray diffraction on single crystals. The previously reported basic atomic arrangement, i.e., a NiAs/Ni2In structure type (P63/mmc, Ni(1) on 2a, 000, Ni(2) with an occupancy ? on 2d, 2/31/31/4, and Sn on 2c, 1/32/31/4), is confirmed. However, strong anisotropic atomic displacements occur for Sn within the a-b plane of the hexagonal unit cell, which require a Gram-Charlier expansion of the probability density function of Sn in order to obtain a good fit to the diffraction data. Direction, magnitude and the concentration dependence of the displacements can be interpreted in terms of the geometrical requirements of the different local atomic configurations in the planes z=+/-1/4, so that the displacements can be identified as static ones.

Leineweber, A.; Oeckler, O.; Zachwieja, U.

2004-03-01

45

Ionization potentials of neutral atoms and positive ions in the limit of large atomic number  

Microsoft Academic Search

The many-electron Schrödinger equation allows one to make predictions for the nonrelativistic ionization potentials of both highly charged positive atomic ions and neutral atoms in the limit of large atomic number Z . Beginning with theoretical configuration interaction data on both Li- and Be-like positive atomic ions by K.T. Chung [Phys. Rev. A 45, 7766 (1992); Phys. Rev. A 47,

Nicolás A. Cordero; Norman H. March; Julio A. Alonso

2007-01-01

46

BRIEF COMMUNICATION: Electrothermal bistability tuning in a large displacement micro actuator  

NASA Astrophysics Data System (ADS)

We report on an approach allowing simple yet efficient tuning of the bistability properties in large displacement micro actuators. The devices fabricated from silicon on insulator (SOI) wafers using a deep reactive ion etching (DRIE)-based process incorporate elastic suspension realized as a pair of beams initially curved in-plane and are operated electrostatically by a comb-drive transducer. The curvature of beam and therefore the stability characteristics of the suspension are controlled by passing a current through the suspension and resistive heating the beam material. Experimental results, which are in good agreement with the finite elements model predictions, demonstrate the feasibility of the suggested approach and show that the application of a small tuning current increases the device deflection from 42 to 56 µm, allows adjustment of the critical snap-through and snap-back voltages and makes it possible the control of latching without an additional electrode. The approach can be efficiently implemented in electrical and optical switches and threshold inertial and mass sensors where the use of long displacement actuators with an adjustable bistability range is beneficial.

Gerson, Y.; Krylov, S.; Ilic, B.

2010-11-01

47

MD simulation of atomic displacements in pure metals and metallic bilayers during low energy ion bombardment at 0K  

NASA Astrophysics Data System (ADS)

Molecular Dynamics (MD) simulations of 100eV Ar ion bombardment of (100) Ni and Al crystals, of bilayer crystals consisting of an Al (or Ni) layer on a (100) Ni (or Al) substrate, as well as pseudo-isotope bilayer crystals have been performed at 0K using tight-binding potentials. For these systems sputtering yields, energy deposition with depth, atomic relocations, production of ad-atoms, depth distributions of vacancies and interstitials per ion impact were studied for times up to 7ps. We observed that both the mean square displacement of atoms and defect production (vacancies, interstitials and ad-atoms) are larger in pure Al than in pure Ni. In addition, we observed for the bilayer systems Al/Ni and Ni/Al a high number of the near surface atomic relocations; especially ion bombardment induced exchange processes between atoms of the 1st (Al or Ni) and of the 2nd (substrate) layer. Potential energy calculations indicate that such relocations between the 1st and the 2nd layer are in both bilayer crystals energetically favourable. Both Al/Ni and Ni/Al bilayers show considerable higher production of ad-atoms as the pure Al and Ni targets. Typically ad-atoms are from the first layer, but in the Ni/Al bilayer system we found a substantial amount of Al ad-atoms from the 2nd layer (first Al layer). They contribute more to the ad-atom number than 1st layer Ni atoms. The mean square displacement of atoms in Al/Ni and Ni/Al crystals increases considerably during the thermal stages of the cascade evolution while it is almost constant in the case of the pure Al and Ni. Finally we observed that the maximum kinetic energies of atoms in the cascade volume after 4ps are lower in the Ni and Al/Ni crystals than in Al and Ni/Al crystals, reflecting the lower cohesive energy of Al as compared to Ni. Calculations with pseudo-isotope bilayer crystals were performed to elucidate the influence of mass or potential on the observed effects.

Kornich, G. V.; Betz, G.

1998-10-01

48

A planar unimorph-based actuator with large vertical displacement capability. I. Experiment  

Microsoft Academic Search

A piezoelectric actuator utilizing a planar arrangement of unimorph elements that produces displacements perpendicular to the plane of the actuator is described. The elements are connected in series mechanically so that the vertical displacement of each element adds to the vertical displacements of the other elements. Two prototype actuators were built and tested. One was stick-built from individual bars of

Daniel E. Glumac; William P. Robbins

1998-01-01

49

Giant atomic displacement at a magnetic phase transition in metastable Mn3O4  

SciTech Connect

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

Hirai, Shigeto [Stanford University; Moreira Dos Santos, Antonio F [ORNL; Shapiro, Max C [Stanford University; Molaison, Jamie J [ORNL; Pradhan, Neelam [ORNL; Guthrie, Malcolm [Carnegie Institution of Washington; Tulk, Christopher A [ORNL; Fisher, Ian R [Stanford University; Mao, Wendy [Stanford University

2013-01-01

50

Giant atomic displacement at a magnetic phase transition in metastable Mn3O4  

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

51

Implementation of tridirectional large lateral shearing displacement interferometry in temperature measurement of a diffused ethylene flame  

NASA Astrophysics Data System (ADS)

A tridirectional large lateral shearing displacement interferometric system has been proposed and used to reconstruct the temperature field of a quasi-axisymmetric diffused ethylene flame in two-dimensional (2D) and three-dimensional (3D) hypotheses. In comparison with the thermocouple results, the 2D reconstructed results affords a quantitative analysis with an average discrepancy between 20 and 40K in the full field, except in the closer part inside the peak temperature location where a high soot volume fraction exists. The 3D reconstructed results affords qualitative analysis and exhibits some asymmetrical characters, but an obvious error occurs at 1cm height where it is not suitable to use the universal correction coefficient.

Lv, Wei; Zhou, Huai-Chun; Zhu, Jin-Rong

2011-07-01

52

Large spin relaxation rates in trapped submerged-shell atoms  

SciTech Connect

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

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

2010-01-15

53

Separate determination of the amplitude of thermal vibrations and static atomic displacements in titanium carbide by neutron diffraction  

SciTech Connect

The amplitude of thermal (dynamic) atomic vibrations and meansquare static atomic displacements in titanium carbide TiC{sub x} (x = 0.97, 0.88, 0.70) have been separately determined by measuring neutron diffraction patterns at two temperatures (T{sub 1} = 300 K and T{sub 2} = 80 K). The static lattice distortions in stoichiometric titanium carbide are experimentally found to be negligible. In the TiC{sub x} homogeneity range, the amplitude {radical}u{sup 2}{sub dyn} of thermal atomic vibrations significantly increases with a decrease in the carbon concentration. The Debye temperature has been determined for the first time in the TiC{sub x} homogeneity range at both room and liquid-nitrogen temperatures.

Khidirov, I., E-mail: khidirov@inp.uz; Parpiev, A. S. [Uzbekistan Academy of Sciences, Institute of Nuclear Physics (Uzbekistan)

2011-05-15

54

Magnetic transport of trapped cold atoms over a large distance  

Microsoft Academic Search

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

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

2001-01-01

55

Large atom number Bose-Einstein condensate machines  

Microsoft Academic Search

We describe experimental setups for producing large Bose-Einstein condensates of 23Na and 87Rb. In both, a high-flux thermal atomic beam is decelerated by a Zeeman slower and is then captured and cooled in a magneto-optical trap. The atoms are then transferred into a cloverleaf-style Ioffe-Pritchard magnetic trap and cooled to quantum degeneracy with radio-frequency-induced forced evaporation. Typical condensates contain 20×106

Erik W. Streed; Ananth P. Chikkatur; Todd L. Gustavson; Micah Boyd; Yoshio Torii; Dominik Schneble; Gretchen K. Campbell; David E. Pritchard; Wolfgang Ketterle

2006-01-01

56

Atomically flat, large-sized, two-dimensional organic nanocrystals.  

PubMed

Large-sized, 2D single crystals of perylene are grown by both solution-cast and physical vapor transport methods. The crystals have a atomically flat parallelogram morphology and the aspect ratios of the lateral extension compared to the thickness are up to 10(3) . The atomically flat feature leads to good interface contact, making a single-crystal field-effect transistor with higher mobility. The mobility of atomically flat crystals can be 10(3) -10(4) times higher than rough crystals. PMID:23172657

Jiang, Hui; Zhang, Keke K; Ye, Jun; Wei, Fengxia; Hu, Peng; Guo, Jun; Liang, Chunyong; Chen, Xiaodong; Zhao, Yang; McNeil, L E; Hu, Wenping; Kloc, Christian

2012-11-22

57

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

58

Continuum-type optimality criteria methods for large finite element systems with a displacement constraint. Part I  

Microsoft Academic Search

Continuum-type optimality criteria for the iterative optimization of “large” finite element systems (i.e. systems with over ten thousand finite elements) are discussed. By investigating optimization problems with up to one million elements and one million variables, it is shown that for a single displacement constraint the proposed method results in a rapid and almost uniform convergence, the rate of which,

G. I. N. Rozvany; M. Zhou; M. Rotthaus; W. Gollub; F. Spengemann

1989-01-01

59

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

PubMed

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

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

2013-05-01

60

A planar unimorph-based actuator with large vertical displacement capability. I. Experiment.  

PubMed

A piezoelectric actuator utilizing a planar arrangement of unimorph elements that produces displacements perpendicular to the plane of the actuator is described. The elements are connected in series mechanically so that the vertical displacement of each element adds to the vertical displacements of the other elements. Two prototype actuators were built and tested. One was stick-built from individual bars of PZT and aluminum, which were epoxied together and connected to each other with short aluminum connector bars. The other was fabricated monolithically from a single plate of PZT by bead-blasting the PZT plate through a steel shadowmask to mill out the desired actuator shape. Copper bars epoxied to the milled-out PZT bars then formed the unimorph elements. The unloaded output displacement of each actuator versus applied voltage was measured as well as the displacement versus applied force with no applied voltage. These measurements were in agreement with the predictions of an electromechanical model of the actuator that has been developed. The model predicted and measurements verified that stiffeners can be added to the basic geometry that will significantly increase the force output without affecting the displacement versus applied voltage characteristic. PMID:18244273

Glumac, D E; Robbins, W P

1998-01-01

61

Compensation of large motion sensor displacements during long recordings of limb movements.  

PubMed

In motion capture applications using electromagnetic tracking systems the process of anatomical calibration associates the technical frames of sensors attached to the skin with the human anatomy. Joint centers and axes are determined relative to these frames. A change of orientation of the sensor relative to the skin renders this calibration faulty. This sensitivity regarding sensor displacement can turn out to be a serious problem with movement recordings of several minutes duration. We propose the "dislocation distance" as a novel method to quantify sensor displacement and to detect gradual and sudden changes of sensor orientation. Furthermore a method to define a so called fixed technical frame is proposed as a robust reference frame which can adapt to a new sensor orientation on the skin. The proposed methods are applied to quantify the effects of sensor displacement of 120 upper and lower limb movement recordings of newborns revealing the need for a method to compensate for sensor displacement. The reliability of the fixed technical frame is quantified and it is shown that trend and dispersion of the dislocation distance can be significantly reduced. A working example illustrates the consequences of sensor displacement on derived angle time series and how they are avoided using the fixed technical frame. PMID:20206358

Karch, Dominik; Kim, Keun-Sun; Wochner, Katarzyna; Philippi, Heike; Pietz, Joachim; Dickhaus, Hartmut

2010-03-04

62

Symmetric displacement algorithms for the timing analysis of large scale circuits  

NASA Astrophysics Data System (ADS)

A number of new techniques for the time domain simulation of MOS circuits based on 'one-sweep' symmetric displacement methods are proposed. Following standard numerical analysis procedures for the characterization of integration methods, the numerical properties of these new techniques are investigated by introducing test problems that are simple enough to be studied analytically and yet complex enough to provide insight on how they will behave in general. The implementation of these methods in timing simulators is described and some experimental results that emphasize the superior accuracy and stability of symmetric displacement techniques are given.

de Micheli, G.; Newton, A. R.; Sangiovanni-Vincentelli, A.

1983-07-01

63

Symmetric displacement algorithms for the timing analysis of large scale circuits  

Microsoft Academic Search

A number of new techniques for the time domain simulation of MOS circuits based on 'one-sweep' symmetric displacement methods are proposed. Following standard numerical analysis procedures for the characterization of integration methods, the numerical properties of these new techniques are investigated by introducing test problems that are simple enough to be studied analytically and yet complex enough to provide insight

G. de Micheli; A. R. Newton; A. Sangiovanni-Vincentelli

1983-01-01

64

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

65

Experiments on Methane Displacement by Carbon Dioxide in Large Coal Specimens  

Microsoft Academic Search

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

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

2011-01-01

66

Large atom number Bose-Einstein condensate of sodium.  

PubMed

We describe the setup to create a large Bose-Einstein condensate containing more than 120 x 10(6) atoms. In the experiment a thermal beam is slowed by a Zeeman slower and captured in a dark-spot magneto-optical trap (MOT). A typical dark-spot MOT in our experiments contains 2.0 x 10(10) atoms with a temperature of 320 microK and a density of about 1.0 x 10(11) atoms/cm(3). The sample is spin polarized in a high magnetic field before the atoms are loaded in the magnetic trap. Spin polarizing in a high magnetic field results in an increase in the transfer efficiency by a factor of 2 compared to experiments without spin polarizing. In the magnetic trap the cloud is cooled to degeneracy in 50 s by evaporative cooling. To suppress the three-body losses at the end of the evaporation, the magnetic trap is decompressed in the axial direction. PMID:17503902

van der Stam, K M R; van Ooijen, E D; Meppelink, R; Vogels, J M; van der Straten, P

2007-01-01

67

Chemical and displacement atomic pair correlations in crystalline solid solutions recovered by anomalous x-ray scattering in Fe-Ni alloys  

SciTech Connect

Short-range pair correlations of atoms in crystalline solid solutions consist of both chemical and displacement correlations. Measurement of these pair correlations is fundamental to understanding the properties of solid solutions. We discuss anomalous scattering techniques which have provided an important advance in our ability to recover these pair correlations and to model the local atomic arrangements in crystalline solid solutions of Fe-Ni alloys.

Ice, G.E.; Sparks, C.J. [Oak Ridge National Lab., TN (United States); Shaffer, L.B. [Anderson Univ., Anderson, IN (United States). Dept. of Physics

1992-12-31

68

Real-time Moment Tensor Inversion and Centroid Location for Large Events from Local and Regional Displacement Records  

NASA Astrophysics Data System (ADS)

We will present here an algorithm to determine the moment tensor and centroid location for large earthquakes employing local and regional real-time displacement records from GPS or GPS/seismic data. The algorithm extracts the coseismic offset from the displacement waveforms and uses the information to invert for the moment tensor. The Green's functions for a layered Earth are obtained numerically from open source code EDGRN. To determine the centroid multiple inversions are performed simultaneously with different centroid coordinates (inversion nodes), the node with the smallest misfit is then assigned the centroid location. We will show results for two example earthquakes in simulated real-time mode using recorded 1 Hz GPS displacements: the 2003 Mw 8.3 Tokachi-Oki and the 2010 Mw 7.2 El Mayor-Cucapah events. We demonstrate that it is feasible with this methodology to obtain accurate source parameters (magnitude, fault plane geometry and style of faulting) within the first 2-3 minutes after rupture initiation, making this methodology amenable for early detection purposes and rapid source modeling.

Melgar-Moctezuma, D.; Bock, Y.; Crowell, B. W.

2011-12-01

69

Large atom number dual-species magneto-optical trap for fermionic 6Li and 40K atoms  

NASA Astrophysics Data System (ADS)

We present the design, implementation and characterization of a dual-species magneto-optical trap (MOT) for fermionic 6Li and 40K atoms with large atom numbers. The MOT simultaneously contains 5.2 × 109 6Li-atoms and 8.0 × 109 40K-atoms, which are continuously loaded by a Zeeman slower for 6Li and a 2D-MOT for 40K. The atom sources induce capture rates of 1.2 × 109 6Li-atoms/s and 1.4 × 109 40K-atoms/s. Trap losses due to light-induced interspecies collisions of ~65% were observed and could be minimized to ~10% by using low magnetic field gradients and low light powers in the repumping light of both atomic species. The described system represents the starting point for the production of a large-atom number quantum degenerate Fermi-Fermi mixture.

Ridinger, A.; Chaudhuri, S.; Salez, T.; Eismann, U.; Fernandes, D. R.; Magalhães, K.; Wilkowski, D.; Salomon, C.; Chevy, F.

2011-11-01

70

The influence of sulfur substitution on the atomic displacement in Bi{sub 2}Ti{sub 2}O{sub 7}  

SciTech Connect

To clarify the role of A{sub 2}O' and B{sub 2}O{sub 6} networks on cation displacement observed in Bi{sub 2}Ti{sub 2}O'O{sub 6}, we used density functional theory calculations to examine the effect of sulfur substitution on the O' and O sites on lone pair formation and resulting atomic displacement observed in Bi{sub 2}Ti{sub 2}O'O{sub 6}. Cation displacement in bismuth titanate is suppressed only when S is substituted on the O' site. Analysis of the electronic structure shows that S substitution on the O' site suppresses the formation of the asymmetric p-type lone pair by modifying the Bi-anion hybridization. Lone pair formation is favored in Bi{sub 2}Ti{sub 2}O'S{sub 6} and the atomic displacement is larger than that observed in Bi{sub 2}Ti{sub 2}O'O{sub 6.} This enhanced displacement is due to weaker Bi-S versus Bi-O interactions leading to significantly stronger hybridization between the Bi and O' states in Bi{sub 2}Ti{sub 2}O'S{sub 6}. We also induced lone pair formation in a metallic bismuth pyrochlore oxide (Bi{sub 2}Ru{sub 2}O'O{sub 6}) by modifying the Bi-O interactions through S substitution on the B{sub 2}O{sub 6} network, indicating atomic displacement on the A{sub 2}O' network may be achieved by modifying the B{sub 2}O{sub 6} network. - Graphical abstract: The electron localization function for Bi{sub 2}Ti{sub 2}O{sub 6}O' and Bi{sub 2}Ti{sub 2}O{sub 6}S' respectively show that sulfur substitution on the O' site will suppress lone pair formation.

Hinojosa, Beverly Brooks; Lang, Paul M. [Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 (United States); Asthagiri, Aravind, E-mail: aasthagiri@che.ufl.ed [Department of Chemical Engineering, University of Florida, Gainesville, FL 32611 (United States)

2010-01-15

71

Displacements of Sb atoms in supersaturated Sb-doped Si layer formed by molecular beam epitaxy growth  

SciTech Connect

Rutherford backscattering channeling measurements with angular scans have been carried out on <100> Sb-doped Si superlattice structures formed by molecular beam epitaxy growth. Three different crystallographic axes <100>, <111>, and <110> have been explored. We have observed Sb displacements from their substitutional sites with displacement amplitudes of 0.22 A ring in as-grown samples. The displacements increase with increasing post-growth annealing temperatures, associated with formation of nanometer size Sb precipitates.

Zhu, Lei; Thompson, Phillip E.; Zhang, Xinghang; Hollander, Mark; Shao, Lin [Ion Beam Laboratory, Department of Nuclear Engineering, Texas A and M University, College Station, Texas 77843 (United States); Code 6812, Naval Research Laboratory, Washington, DC 20375-5347 (United States); Department of Mechanical Engineering, Texas A and M University, College Station, Texas 77843-3123 (United States); Ion Beam Laboratory, Department of Nuclear Engineering, Texas A and M University, College Station, Texas 77843 (United States)

2007-04-15

72

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

73

Synthesis and photoresponse of large GaSe atomic layers.  

PubMed

We report the direct growth of large, atomically thin GaSe single crystals on insulating substrates by vapor phase mass transport. A correlation is identified between the number of layers and a Raman shift and intensity change. We found obvious contrast of the resistance of the material in the dark and when illuminated with visible light. In the photoconductivity measurement we observed a low dark current. The on-off ratio measured with a 405 nm at 0.5 mW/mm(2) light source is in the order of 10(3); the photoresponsivity is 17 mA/W, and the quantum efficiency is 5.2%, suggesting possibility for photodetector and sensor applications. The photocurrent spectrum of few-layer GaSe shows an intense blue shift of the excitation edge and expanded band gap compared with bulk material. PMID:23731066

Lei, Sidong; Ge, Liehui; Liu, Zheng; Najmaei, Sina; Shi, Gang; You, Ge; Lou, Jun; Vajtai, Robert; Ajayan, Pulickel M

2013-06-03

74

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

75

Spatial and temporal film thickness measurement of a soap bubble based on large lateral shearing displacement interferometry.  

PubMed

The film thickness of a hanging soap bubble has been studied along its gravitational orientation after its birth and before its bursting using large lateral shearing displacement interferometry, with a theoretical error of less than 0.325?. The results show that the spatial distribution of the film thickness could be approximated with an exponential model in all captured frames, especially in the lower half of the soap bubble. Before its bursting, a special zone, where the water layer has drained out while the surfactant solution layer remains, will occur at the top of the soap bubble and gradually expand toward the bottom. Moreover, the simulated fringe patterns based on the computed values match well with the experimentally observed ones. PMID:23262626

Lv, Wei; Zhou, Huaichun; Lou, Chun; Zhu, Jinrong

2012-12-20

76

Entanglement of large atomic samples: A Gaussian-state analysis  

SciTech Connect

We present a Gaussian-state analysis of the entanglement generation between two macroscopic atomic ensembles due the continuous probing of collective spin variables by optical Faraday rotation. The evolution of the mean values and the variances of the atomic variables is determined, and the entanglement is characterized by the Gaussian entanglement of formation and the logarithmic negativity. The effects of induced opposite Larmor rotation of the samples and of light absorption and atomic decay are analyzed in detail.

Sherson, Jacob; Moelmer, Klaus [QUANTOP, Danish Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK 8000 Aarhus C (Denmark)

2005-03-01

77

The liquid state of large clusters with pairwise atomic interactions  

Microsoft Academic Search

Formation of the liquid state for clusters with a pair interaction between atoms is examined within the framework of the void model, in which configurational excitation of atoms results from formation of voids. Void parameters are found from computer simulation by molecular dynamics methods for Lennard-Jones clusters and from real thermodynamic parameters of the liquid states of condensed inert gases.

R. S. Berry; B. M. Smirnov

2005-01-01

78

An extensional piggyback model for large apparent displacements along major ``thrusts'': examples from nappes of the Norwegian Caledonides (Invited)  

NASA Astrophysics Data System (ADS)

Many collisional orogens are characterized by large-scale thrusts or nappes with postulated horizontal displacements over the underlying basement exceeding 100 km. For example the Jotun Nappe of the Norwegian Caledonides has long been credited with over 300 km of lateral thrusting. A model is proposed where initial thrusting is succeeded by passive transport on top of an exhuming high pressure/ultrahigh pressure (HP/UHP) metamorphic terrane. The initial thrusting occurs when cratons collide and the leading edge of one craton is subducted beneath the other and plunged deeply into the mantle where it undergoes HP/UHP metamorphism, partial melting and the insertion of peridotites from the overlying mantle wedge. The subsequent exhumation of the subducted terrane can be accomplished by true extension, which effectively “pulls” the crustal terrane and underlying continental lithosphere out of the mantle, or by buoyancy driven crustal extrusion, which allows the crustal slab to insert itself into the overlying crust bounded below and above by a thrust fault and a low angle normal fault, respectively, or by a combination of both mechanisms. In both models, the shear traction along the top of the exhuming terrane will reverse from the earlier thrust motion (top to the foreland) to a normal displacement (top to the hinterland). The resultant shear can detach the leading edge of the upper plate from the rest of the plate allowing it to be carried passively towards the foreland on the exhuming plate with the length of transport a function of the amount of exhumation of the lower plate. The Jotun Nappe and the nappes of the Trondheim Basin were thrust (sensu stricto) unknown distances towards foreland during the early phases of the Scandian Orogeny (ca. 430-415 ma) when the western edge of Baltica was subducted into the mantle beneath the eastern margin of Laurentia. The subducted edge of Baltica was metamorphosed into a HP/UHP terrane known as the Western Gneiss Region (WGR). Kinematic indicators along the basal decollément of the Jotun Nappe and below and within the Upper and Middle Allochthons of the Trondheim Basin indicate a change in shear sense from top to the east to top to the west at essentially the same time the WGR began its exhumation out of the mantle at ca. 415 Ma. The normal sense shear along the top of the exhuming HP/UHP plate ultimately separated the leading edges of the overlying plates away from their main body, which were then carried passively (i.e. no more shear tractions along the basal decollément) or semi-passively (distributed shear along the basal decollément) eastward as the WGR was exhumed between 415-390 Ma. Thus the total apparent displacement of ca. 300 km for the Jotun Nappe was only partly the result of thrusting; most of it was the result of piggyback transport on top of the exhuming WGR. A similar mechanism can explain the present positions of other Caledonian Allochthons along the length of the orogen as well as purported large-scale nappes and thrusts in other mountain systems.

Brueckner, H. K.

2010-12-01

79

Thickness measurement of full field soap bubble film in real time based on large lateral shearing displacement interferometry  

NASA Astrophysics Data System (ADS)

Soap bubble has a profile nearly the same as a perfect sphere. Many researches focus on the measurement of the film thickness of the soap bubble over time in order to calculate the film drainage rate. Its thickness variation in gravitation field can be respectively approximated with many models, considering the cost and precision in different applications. In this research, fringe patterns of a soap bubble were captured continuously using the large lateral shearing displacement interferometry during the process from its formation to burst. From the analysis of three typical frames, it can be seen that the film thickness distribution along the gravity orientation shows a very good agreement with an exponential model. The ratio of its maximum error to the laser wavelength is 3/8, existing at the sphere's center. Moreover, it can be seen that the absolute value of the parameter k in the exponential model keeps increasing over time, while the parameter b keeps decreasing over time. Based on the parameter k from the exponential model, the maximum limit in the thickness measurement of the soap bubble film can be calculated from the function of the fringe pattern's resolution and its field coordinates. The result shows that there is a special point above the sphere's center, being the right place where the gradient of phase order changes its sign. The region near this point presents very high limitation in the film thickness measurement.

Lv, Wei; Zhou, Huai-Chun; Zhu, Jin-Rong

2012-03-01

80

Angular coefficients in large-scale atomic structure calculations  

Microsoft Academic Search

Recent calculations on atomic structure and properties have used sets of configurational states (CSFs) of dimension O(10), much larger than was envisaged in the 1970s when programs such as MCHF and GRASP were designed. Current algorithms for reducing matrix elements between open shell CSFs to a sum of Slater integrals account for a substantial part of the computational cost of

Ian P. Grant

2004-01-01

81

Atomic force microscope investigation of large-circle DNA molecules  

Microsoft Academic Search

A circular bacterial artificial chromosome of 148.9kbp on human chromosome 3 has been extended and fixed on bare mica substrates using a developed fluid capillary flow method in evaporating liquid drops. Extended circular DNA molecules were imaged with an atomic force microscope (AFM) under ambient conditions. The measured total lengths of the whole DNA molecules were in agreement with sequencing

Aiguo Wu; Lihua Yu; Zhuang Li; Huanming Yang; Erkang Wang

2004-01-01

82

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

83

Neutron scattering studies of short-range order, atomic displacements, and effective pair interactions in a null-matrix Ni0.5262Pt0.48 crystal  

NASA Astrophysics Data System (ADS)

The best known exception to the Heine-Sampson and Bieber-Gauthier arguments for ordering effects in transition metal alloys (similar to the Hume-Rothery rules) is a NiPt alloy, whose phase diagram is similar to that of the CuAu system. Using neutron scattering we have investigated the local atomic order in a null-matrix Ni0.5262Pt0.48 single crystal. In a null-matrix alloy, the isotopic composition is adjusted so that the average neutron scattering length vanishes ( Ni62 has a negative scattering length nearly equal in magnitude to that of Pt). Consequently, all contributions to the total scattering depending on the average lattice are suppressed. The only remaining components of the elastic scattering are the short-range order (SRO) and size effect terms. These data permit the extraction of the SRO parameters (concentration-concentration correlations) as well as the displacement parameters (concentration-displacement correlations). Using the Krivoglaz-Clapp-Moss theory, we obtain the effective pair interactions (EPIs) between near neighbors in the alloy. The results can be used by theorists to model the alloy in the context of the electronic theory of alloy phase stability, including a preliminary evaluation of the local species-dependent displacements. Our maps of V(q) , the Fourier transform of the EPIs, show very similar shapes in the experimental and reconstructed data. This is of importance when comparing to electronic structure calculations.

Rodriguez, J. A.; Moss, S. C.; Robertson, J. L.; Copley, J. R. D.; Neumann, D. A.; Major, J.

2006-09-01

84

Excitation of heavy hydrogenlike ions by light atoms in relativistic collisions with large momentum transfers  

NASA Astrophysics Data System (ADS)

We present a theory for excitation of heavy hydrogenlike projectile ions by light target atoms in collisions where the momentum transfers to the atom are very large on the atomic scale. It is shown that in this process the electrons and the nucleus of the atom behave as (quasi-) free particles with respect to each other and that their motion is governed by the field of the nucleus of the ion. The effect of this field on the atomic particles can be crucial for the contribution to the excitation of the ion caused by the electrons of the atom but, because of large nuclear mass, may be neglected in the contribution to the excitation due to the nucleus of the atom. The theory is applied to calculate excitation of Bi82+(1s) ions in collisions with hydrogen.

Najjari, B.; Voitkiv, A. B.

2012-05-01

85

Reversible displacement of chemisorbed n-alkanethiol molecules on Au(111) surfaces. An atomic force microscopy study  

Microsoft Academic Search

Atomic force microscopy has been used to study the structure and the stability of CH[sub 3](CH[sub 2])[sub 9]SH and CH[sub 3](CH[sub 2])[sub 17]SH molecules self-assembled on a Au(111) surface as a function of the load applied by the tip. Atomic resolution images taken during a loading and unloading cycle have revealed two sudden transitions corresponding to changes of the periodicity

G. Y. Liu; M. B. Salmeron

1994-01-01

86

Atomic force microscope investigation of large-circle DNA molecules.  

PubMed

A circular bacterial artificial chromosome of 148.9kbp on human chromosome 3 has been extended and fixed on bare mica substrates using a developed fluid capillary flow method in evaporating liquid drops. Extended circular DNA molecules were imaged with an atomic force microscope (AFM) under ambient conditions. The measured total lengths of the whole DNA molecules were in agreement with sequencing analysis data with an error range of +/-3.6%. This work is important groundwork for probing single nucleotide polymorphisms in the human genome, mapping genomic DNA, manipulating biomolecular nanotechnology, and studying the interaction of DNA-protein complexes investigated by AFM. PMID:14751264

Wu, Aiguo; Yu, Lihua; Li, Zhuang; Yang, Huanming; Wang, Erkang

2004-02-15

87

A methodology for studying the high wall displacement of large scale underground cavern complexes and it’s applications  

Microsoft Academic Search

A great number of numerical simulations of multiple schemes were conducted to investigate the stability of underground cavern complexes in three representative hydropower stations in China. The purpose was to study the displacement law of side walls of underground openings under different conditions. In the calculation, four major typical rocks, four overburden thicknesses, and five geo-stress conditions were taken into

W. S. Zhu; B. Sui; X. J. Li; S. C. Li; W. T. Wang

2008-01-01

88

Fiber optic displacement sensor with a large extendable measurement range while maintaining equally high sensitivity, linearity, and accuracy.  

PubMed

This paper presents a fiber optic displacement sensor composed of a transmissive grating panel, a reflection mirror, and two optical fibers as a transceiver. The proposed fiber optic displacement sensor guarantees a stable reflected signal acquisition for application in real industrial fields. Through a parametric study of the grating pitch of the transmissive grating panel, the signal-to-noise ratio, linearity, resolution, accuracy error, and sensitivity of the proposed sensor were investigated. The measured bidirectional movement demonstrated a peak to peak accuracy of 10.5 ?m, high linearity of 0.9996, resolution of 3.1 ?m at the full bandwidth, signal-to-noise ratio of 27.7, and high sensitivity of 31.8 ?m/rad during a movement of 16,004.0 ?m using the transmissive grating panel, which had a grating pitch of 200 ?m. Even for an extended measurement range, the proposed scheme enables the same accuracy, linearity, and sensitivity to be maintained when compared with conventional laser displacement sensors and fiber optic displacement sensors. PMID:22559566

Lee, Yeon-Gwan; Kim, Yoon-Young; Kim, Chun-Gon

2012-04-01

89

A Large Dodecahedral Cluster Containing about 480 Atoms in a 2/1 Cubic Crystalline Approximant  

NASA Astrophysics Data System (ADS)

A dodecahedral atom cluster, which is the largest atom cluster with icosahedral symmetry found in crystalline alloy phases, was observed in the cubic crystalline phase of ?-(AlPdMnSi), referred to as a 2/1 approximant of an icosahedral quasicrystal, with a lattice constant of 2.0211 nm. The large dodecahedral cluster has a diameter of about 2.6 nm and contains about 480 atoms. The atomic arrangement of the dodecahedral cluster is divided into atomic shells with icosahedral symmetry, and most of the atoms in the shells are located at special positions associated with the golden mean in the three-dimensional Penrose lattice. A small icosahedral atom cluster, formed with twelve Al atoms at the vertices and a Pd atom at the center, is located at each vertex of a dodecahedral shell with a diameter of about 2 nm. The large dodecahedral atom cluster is considered to be an important cluster for understanding the structure of an Al Pd Mn icosahedral quasicrystal.

Hiraga, Kenji; Ohsuna, Tetsu; Sugiyama, Kazumasa

1998-05-01

90

Atomic and electronic structures of large and small carbon tori  

NASA Astrophysics Data System (ADS)

The stability of large carbon tori is examined within the elasticity theory. Tori of diameter larger than 200 nm obtained by bending a single-wall nanotube and connecting the two ends together are proved to be stable. Molecular mechanics is used for optimizing the structure of a small polygonal torus (C1960) obtained by connecting short portions of (6,6) and (10,0) nanotubes with ten pairs of pentagons and heptagons. The electronic structures of both small and large tori are determined within the framework of a tight-binding Hamiltonian, and their energies are compared. By application of London theory, it is shown that a magnetic field deeply influences the electronic structure of the carbon tori.

Meunier, V.; Lambin, Ph.; Lucas, A. A.

1998-06-01

91

Effective-range corrections to three-body recombination for atoms with large scattering length  

NASA Astrophysics Data System (ADS)

Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as ?a4/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate constant, which are due to the effective range of the atoms, and study the correlation between the rate constant and the atom-dimer scattering length. Our results are applied to He4 atoms as a test case.

Hammer, H.-W.; Lähde, Timo A.; Platter, L.

2007-03-01

92

Rapid Detection and Characterization of Medium to Large Earthquakes Using Absolute Displacement Waveforms from GPS and Seismic Data  

NASA Astrophysics Data System (ADS)

We have developed and implemented an early warning system for natural hazards such as earthquakes, volcanoes, and tsunamis. It relies on a dense network of real-time GPS stations with average spacing in the 20-40 km range, with a subset of stations co-located with seismic instruments. Japan’s GEONET, the Western Canada Deformation Array (WCDA), the Bay Area Regional Deformation Network (BARD), parts of the Plate Boundary Observatory (PBO) and the California Real-Time Network (CRTN) are examples of networks that fulfill these requirements. Total (dynamic + static) displacement waveforms are computed once per second for all available network stations using a combination of GPS and seismic data obtained by instantaneous GPS positioning and multi-rate Kalman filtering. Anomalous strain detection is determined by first creating a Delaunay triangulation grid over all stations. The two principle components of strain rate are computed in each triangle from relative changes in the lengths of the sides of the triangles. Once strain reaches a pre-specified threshold, an alert is disseminated to key personnel. The alert contains the time in GMT, each station in the triangle and the value of the maximum principal component of strain. As we show in examples from the 2008 Southern California ShakeOut and 2003 Tokachi-Oki earthquakes, strain detection can be in the first few seconds or up to 20 seconds or more after the initiation of the earthquake. We comment here on strain detection thresholds and our experience with false detections. The next step is to determine the earthquake hypocenter, which is performed when displacements of four or more stations exceed preset criteria of total displacement. The system currently uses 0.1 m, which is 5-10 times greater than the precision of a single-epoch displacement estimates. The next step is to determine earthquake magnitude. We are investigating rapid modeling of earthquake magnitude through empirical scaling relationships derived from a comparison of coseismic and total displacements, each decaying as a different function of epicentral distance.

Bock, Y.; Crowell, B. W.

2009-12-01

93

A probable vacuum state containing a large number of hydrogen atom of excited state or ground state K, Rb or Cs atom  

Microsoft Academic Search

The linear Stark effect shows that the first excited state of hydrogen atom has large permanent electric dipole moment (EDM), d(H)=3eao (ao is Bohr radius). Using special capacitors our experiments discovered that the ground state K, Rb or Cs atom is polar atom with a large EDM of the order of eao as hydrogen atom of excited state. Their capacitance(C)

Pei-Lin You

2008-01-01

94

Self-alignment of a compact large-area atomic Sagnac interferometer  

NASA Astrophysics Data System (ADS)

We report on the realization of a compact atomic Mach-Zehnder-type Sagnac interferometer of 13.7 cm length, which covers an area of 19 mm2 previously reported only for large thermal beam interferometers. According to Sagnac's formula, which holds for both light and atoms, the sensitivity for rotation rates increases linearly with the area enclosed by the interferometer. The use of cold atoms instead of thermal atoms enables miniaturization of Sagnac interferometers without sacrificing large areas. In comparison with thermal beams, slow atoms offer better matching of the initial beam velocity and the velocity with which the matter waves separate. In our case, the area is spanned by a cold atomic beam of 2.79 m s-1, which is split, deflected and combined by driving a Raman transition between the two hyperfine ground states of 87Rb in three spatially separated light zones. The use of cold atoms requires a precise angular alignment and high wave front quality of the three independent light zones over the cloud envelope. We present a procedure for mutually aligning the beam splitters at the microradian level by making use of the atom interferometer itself in different configurations. With this method, we currently achieve a sensitivity of 6.1\\times 10^{-7}\\, {rad}\\, {s}^{-1}\\,Hz^{-1/2} .

Tackmann, G.; Berg, P.; Schubert, C.; Abend, S.; Gilowski, M.; Ertmer, W.; Rasel, E. M.

2012-01-01

95

Large-photon-number extraction from individual atoms trapped in an optical lattice  

SciTech Connect

The atom-by-atom characterization of quantum gases requires the development of novel measurement techniques. One particularly promising new technique demonstrated in recent experiments uses strong fluorescent laser scattering from neutral atoms confined in a short-period optical lattice to measure the positions of individual atoms in the sample. A crucial condition for the measurements is that atomic hopping between lattice sites must be strongly suppressed despite substantial photon recoil heating. This paper models three-dimensional polarization gradient cooling of atoms trapped within a far-detuned optical lattice. The atomic dynamics are simulated using a hybrid Monte Carlo and master-equation analysis in order to predict the frequency of processes which give rise to degradation or loss of the fluorescent signal during measurements. It is shown, consistently with the experimental results, that there exists a wide parameter range in which the lifetime of strongly fluorescing isolated lattice-trapped atoms is limited by background gas collisions rather than radiative processes. In these cases the total number of scattered photons can be as large as 10{sup 8} per atom. The performance of the technique is related to relevant experimental parameters.

Shotter, M. D. [Department of Physics, University of Oxford, Oxford OX1 3PU (United Kingdom) and National Institute of Standards and Technology, 100 Bureau Drive, Stop 8423, Gaithersburg, Maryland 20899-8423 (United States)

2011-03-15

96

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

97

Three-Body Recombination of {sup 6}Li Atoms with Large Negative Scattering Lengths  

SciTech Connect

The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of {sup 6}Li atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.

Braaten, Eric; Kang, Daekyoung; Platter, Lucas [Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States); Hammer, H.-W. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie) and Bethe Center for Theoretical Physics, Universitaet Bonn, 53115 Bonn (Germany)

2009-08-14

98

Three-body recombination of 6Li atoms with large negative scattering lengths.  

PubMed

The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of 6Li atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold. PMID:19792641

Braaten, Eric; Hammer, H-W; Kang, Daekyoung; Platter, Lucas

2009-08-13

99

Three-Body Recombination of Li6 Atoms with Large Negative Scattering Lengths  

NASA Astrophysics Data System (ADS)

The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for the general case of 3 different scattering lengths. Our general result is applied to the three lowest hyperfine states of Li6 atoms. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.

Braaten, Eric; Hammer, H.-W.; Kang, Daekyoung; Platter, Lucas

2009-08-01

100

On the refinement of time-resolved diffraction data: comparison of the random-distribution and cluster-formation models and analysis of the light-induced increase in the atomic displacement parameters  

SciTech Connect

Expressions for the random-distribution and cluster-formation models for light-induced changes in crystals studied by time-resolved diffraction are presented. The two models can be distinguished on the basis of differences in the predicted intensities. The light-induced increase in the atomic displacement parameters is analyzed with both simulated and experimental data sets.

Vorontsov, Ivan I.; Coppens, Philip (SUNYB)

2010-07-20

101

Three-body Recombination of Fermionic Atoms with Large Scattering Lengths  

NASA Astrophysics Data System (ADS)

The 3-body recombination rate at threshold for fermions with three spin states and large scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the three scattering lengths and the Efimov parameter, which can be complex valued. Semi-analytic results are obtained for the cases of negative scattering lengths, two of which are equal. The general result is applied to the three lowest hyperfine states of Lithium-6 atoms in regions of the magnetic field in which the three scattering lengths are all large and negative. Comparisons with recent experiments provide indications of loss features associated with Efimov trimers near the 3-atom threshold.

Kang, Daekyoung; Braaten, Eric; Hammer, Hans-Werner; Platter, Lucas

2009-05-01

102

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

SciTech Connect

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

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

1981-01-01

103

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

104

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

SciTech Connect

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

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

2003-02-01

105

Effective-range corrections to three-body recombination for atoms with large scattering length  

SciTech Connect

Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as ({Dirac_h}/2{pi})a{sup 4}/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate constant, which are due to the effective range of the atoms, and study the correlation between the rate constant and the atom-dimer scattering length. Our results are applied to {sup 4}He atoms as a test case.

Hammer, H.-W.; Laehde, Timo A.; Platter, L. [Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Universitaet Bonn, 53115 Bonn (Germany); Department of Physics, University of Washington, Seattle, Washington 98195-1560 (United States); Department of Physics and Astronomy, Ohio University, Athens, Ohio 45701 (United States)

2007-03-15

106

A large range metrological atomic force microscope and its uncertainty analysis  

NASA Astrophysics Data System (ADS)

The atomic force microscope (AFMs) is widely used in nanotechnology research and industry. To ensure the quantity consistency, the measurement precision of these machines must be calibrated and trace back to SI international unit. In the calibration process, first the standard grating pitch artifact is calibrated by metrological atomic force microscope which has the direct tracing capability; then the grating pitch artifact is transferred to calibrate the common AFMs. Because the importance of metrological atomic force microscope in nanometer tracing, the NIM of China has developed a large range metrological atomic force microscope with 50mm×50mm×2mm scan area. In this paper, the structure and performance of this instrument will be introduced briefly. The instrument utilizes a series of novel designs like hybrid air bearing and sliding guide platform, three dimensional orthogonal piezo scanner head, multi-pass interferometer and Fourier harmonic components separation method to achieve both high precision measurement in small area and fast measurement in large area. As a metrological instrument, the error sources and uncertainties of mAFM are also analyzed, theoretical analysis and experiments show the standard uncertainty of the mAFM is less than 2nm in small range and 20nm in large range

Gao, S.; Li, Q.; Li, W.; Lu, M.; Shi, Y.

2013-05-01

107

Production of exotic atoms at energies available at the CERN Large Hadron Collider  

SciTech Connect

We study in details the space-time dependence of the production of muonic, pionic, and other exotic atoms by the coherent photon exchange between nuclei at the Large Hadron Collider at CERN. We show that a multipole expansion of the electromagnetic interaction yields an useful insight of the bound-free production mechanism which has not been explored in the literature. Predictions for the spatial, temporal, and angular distribution, as well as the total cross sections, for the production of exotic atoms are also included.

Bertulani, C. A.; Ellermann, M. [Department of Physics and Astronomy, Texas A and M University-Commerce, Commerce, Texas 75429 (United States)

2010-04-15

108

Electronic transport in large systems through a QUAMBO–NEGF approach: Application to atomic carbon chains  

NASA Astrophysics Data System (ADS)

The conductance of single-atom carbon chain (SACC) between two zigzag graphene nanoribbons (GNR) is studied by an efficient scheme utilizing tight-binding (TB) parameters generated via quasi-atomic minimal basis set orbitals (QUAMBOs) and non-equilibrium Green's function (NEGF). Large systems (SACC contains more than 50 atoms) are investigated and the electronic transport properties are found to correlate with SACC's parity. The SACCs provide a stable off or on state in broad energy region (0.1–1 eV) around Fermi energy. The off state is not sensitive to the length of SACC while the corresponding energy region decreases with the increase of the width of GNR.

Fang, X. W.; Zhang, G. P.; Yao, Y. X.; Wang, C. Z.; Ding, Z. J.; Ho, K. M.

2011-10-01

109

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

110

High-performance experimental apparatus for large atom number 87Rb Bose-Einstein condensates  

NASA Astrophysics Data System (ADS)

We describe our high-performance experimental apparatus for producing large atom number 87Rb Bose-Einstein condensates by using a double magneto-optical trap (MOT) system that consists of a two-dimensional MOT (2D MOT) and a three-dimensional MOT (3D MOT). As an atomic beam source for loading the 3D MOT, we use a unique 2D MOT system with two-color pushing beams, which increase the loading rate and the total number of atoms in the 3D MOT, compared to a pure 2D MOT by a factor of 20. After MOT compression and polarization gradient cooling, atoms are optically pumped into a magnetically trappable hyperfine state | F = 1, m F = -1> to be loaded into a quadrupole-Ioffe-configuration (QUIC) trap. We enhance this optical pumping process by up to 300% by using two laser beams. After rf evaporative cooling, a Bose-Einstein condensate (BEC) with more than 2 × 107 atoms is achieved.

Noh, Jiho; Park, Sung Jong; Park, Chang Yong; Lee, Won-Kyu; Yu, Dai-Hyuk; Mun, Jongchul

2012-10-01

111

Large scale growth and characterization of atomic hexagonal boron nitride layers.  

PubMed

Hexagonal boron nitride (h-BN), a layered material similar to graphite, is a promising dielectric. Monolayer h-BN, so-called "white graphene", has been isolated from bulk BN and could be useful as a complementary two-dimensional dielectric substrate for graphene electronics. Here we report the large area synthesis of h-BN films consisting of two to five atomic layers, using chemical vapor deposition. These atomic films show a large optical energy band gap of 5.5 eV and are highly transparent over a broad wavelength range. The mechanical properties of the h-BN films, measured by nanoindentation, show 2D elastic modulus in the range of 200-500 N/m, which is corroborated by corresponding theoretical calculations. PMID:20698639

Song, Li; Ci, Lijie; Lu, Hao; Sorokin, Pavel B; Jin, Chuanhong; Ni, Jie; Kvashnin, Alexander G; Kvashnin, Dmitry G; Lou, Jun; Yakobson, Boris I; Ajayan, Pulickel M

2010-08-11

112

Synthesis of large-area MoS2 atomic layers with chemical vapor deposition.  

PubMed

Large-area MoS(2) atomic layers are synthesized on SiO(2) substrates by chemical vapor deposition using MoO(3) and S powders as the reactants. Optical, microscopic and electrical measurements suggest that the synthetic process leads to the growth of MoS(2) monolayer. The TEM images verify that the synthesized MoS(2) sheets are highly crystalline. PMID:22467187

Lee, Yi-Hsien; Zhang, Xin-Quan; Zhang, Wenjing; Chang, Mu-Tung; Lin, Cheng-Te; Chang, Kai-Di; Yu, Ya-Chu; Wang, Jacob Tse-Wei; Chang, Chia-Seng; Li, Lain-Jong; Lin, Tsung-Wu

2012-03-30

113

Effective-range corrections to three-body recombination for atoms with large scattering length  

Microsoft Academic Search

Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as ℏa4\\/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate

H.-W. Hammer; Timo A. Lähde; L. Platter

2007-01-01

114

Effective-range corrections to three-body recombination for atoms with large scattering length  

Microsoft Academic Search

Few-body systems with large scattering length a have universal properties that do not depend on the details of their interactions at short distances. The rate constant for three-body recombination of bosonic atoms of mass m into a shallow dimer scales as (\\/2)a\\/m times a log-periodic function of the scattering length. We calculate the leading and subleading corrections to the rate

L. Platter; Timo A. Laehde; H.-W. Hammer

2007-01-01

115

Three-Body Recombination of Li Atoms with Large Negative Scattering Lengths  

Microsoft Academic Search

The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for

Eric Braaten; Daekyoung Kang; Lucas Platter; H.-W. Hammer

2009-01-01

116

Three-Body Recombination of Li6 Atoms with Large Negative Scattering Lengths  

Microsoft Academic Search

The three-body recombination rate at threshold for distinguishable atoms with large negative pair scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the 3 scattering lengths and the Efimov parameter, which can be complex-valued. We provide semianalytic expressions for the cases of 2 or 3 equal scattering lengths, and we obtain numerical results for

Eric Braaten; H.-W. Hammer; Daekyoung Kang; Lucas Platter

2009-01-01

117

Effective-range corrections to three-body recombination for atoms with large scattering length  

Microsoft Academic Search

Few-body systems with large scattering length a have universal properties\\u000athat do not depend on the details of their interactions at short distances. The\\u000arate constant for three-body recombination of bosonic atoms of mass m into a\\u000ashallow dimer scales as \\\\hbar a^4\\/m times a log-periodic function of the\\u000ascattering length. We calculate the leading and subleading corrections to the

H.-W. Hammer; Timo A. Lahde; L. Platter

2007-01-01

118

A convenient method of aligning large DNA molecules on bare mica surfaces for atomic force microscopy.  

PubMed

Large DNA molecules remain difficult to be imaged by atomic force microscopy (AFM) because of the tendency of aggregation. A method is described to align long DNA fibers in a single direction on unmodified mica to facilitate AFM studies. The clear background, minimal overstretching, high reproducibility and convenience of this aligning procedure make it useful for physical mapping of genome regions and the studies of DNA-protein complexes. PMID:9753751

Li, J; Bai, C; Wang, C; Zhu, C; Lin, Z; Li, Q; Cao, E

1998-10-15

119

A convenient method of aligning large DNA molecules on bare mica surfaces for atomic force microscopy.  

PubMed Central

Large DNA molecules remain difficult to be imaged by atomic force microscopy (AFM) because of the tendency of aggregation. A method is described to align long DNA fibers in a single direction on unmodified mica to facilitate AFM studies. The clear background, minimal overstretching, high reproducibility and convenience of this aligning procedure make it useful for physical mapping of genome regions and the studies of DNA-protein complexes.

Li, J; Bai, C; Wang, C; Zhu, C; Lin, Z; Li, Q; Cao, E

1998-01-01

120

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

2012-04-17

121

Guest displacement in silicon clathrates  

Microsoft Academic Search

We study both theoretically and experimentally the structure of the doped silicon clathrate II NaxSi34. We find that contrary to published works, the sodium atoms do not retain the Td symmetry inside the Si28 cages and move about 1 Å away from the center of the cage. This displacement, in conjunction with that of a sodium atom in an adjacent

Florent Tournus; Bruno Masenelli; Patrice Mélinon; Damien Connétable; Xavier Blase; Anne Marie Flank; Pierre Lagarde; Christian Cros; Michel Pouchard

2004-01-01

122

Effects of threshold displacement energy on defect production by displacement cascades in ?, ? and ?-LiAlO2  

NASA Astrophysics Data System (ADS)

Threshold displacement energy evaluation and a series of displacement cascade simulations in ?, ?, and ?-LiAlO2 were performed using molecular dynamics. Threshold displacement energy evaluations indicated that higher absolute ionic charge values and larger densities both increase threshold displacement energy. The displacement cascade simulations suggest that the influence of different crystal structures on the number of interstitial atoms generated in a displacement cascade is explainable almost entirely by the difference of the threshold displacement energy.

Tsuchihira, H.; Oda, T.; Tanaka, S.

2013-11-01

123

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

124

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

SciTech Connect

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

Datz, S.

1989-06-12

125

Towards sympathetic cooling of large molecules: cold collisions between benzene and rare gas atoms  

NASA Astrophysics Data System (ADS)

This paper reports on calculations of collisional cross sections for the complexes X-C6H6 (X=3He, 4He, Ne) at temperatures in the range 1 ?K-10 K and shows that relatively large cross sections in the 103-105 Å2 range are available for collisional cooling. Both elastic and inelastic processes are considered in this temperature range. The calculations suggest that sympathetically cooling benzene to microkelvin temperatures is feasible using these co-trapped rare gas atoms in an optical trap.

Barletta, P.; Tennyson, J.; Barker, P. F.

2009-05-01

126

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

127

Displacement cascades in diatomic materials  

SciTech Connect

A new function, the specified-projectile displacement function p/sub ijk/ (E), is introduced to describe displacement cascades in polyatomic materials. This function describes the specific collision events that produce displacements and hence adds new information not previously available. Calculations of p/sub ijk/ (E) for MgO, Al/sub 2/O/sub 3/ and TaO are presented and discussed. Results show that the parameters that have the largest effect on displacement collision events are the PKA energy and the mass ratio of the atom types in the material. It is further shown that the microscopic nature of the displacement events changes over the entire recoil energy range relevant to fusion neutron spectra and that these changes are different in materials whose mass ratio is near one than in those where it is far from one.

Parkin, D.M.; Coulter, C.A.

1981-01-01

128

Calculation of the atomic spin densities and energy band gaps of carbon high-spin aromatic (pi) large macromolecular systems  

Microsoft Academic Search

In this work we have calculated the atomic spin densities and energy band gaps of three kinds of large carbon unlocalized high-spin aromatic systems, consisting of 1000 to 10 000 atoms. The selected systems, nanotubes, graphenes, and polyaryls, have obvious theoretical and technical interest. The results obtained for nanotubes and graphenes confirm and expand the ones published by other authors.

J. R. A´lvarez Collado

2008-01-01

129

Investigation of The Synergistic Influence of Irradiation Temperature and Atomic Displacement Rate on the Microstructural Evolution of Ion-Irradiated Model Austenitic Alloy Fe-15Cr-16Ni  

SciTech Connect

A comprehensive experimental investigation of microstructural evolution has been conducted on Fe-15Cr-16Ni irradiated with 4.0 MeV nickel ions in the High Fluence Irradiation Facility of the University of Tokyo. Irradiations proceeded to dose levels ranging from ~0.2 to ~26 dpa at temperatures of 300, 400 and 500 degrees C at displacement rates of 1 x 10^-4, 4 x 10^-4 and 1 x 10^-3 dpa/sec. This experiment is one of two companion experiments directed toward the study of the dependence of void swelling on displacement rate. The other experiment proceeded at seven different but lower dpa rates in FFTF-MOTA at ~400 degrees C. In both experiments the swelling was found at every irradiation condition studied to monotonically increase with decreases in dpa rate. The microstructural evolution under ion irradiation was found to be very sensitive to the displacement rate at all three temperatures. The earliest and most sensitive component of microstructure to both temperature and especially displacement rate was found to be the Frank loops. The second most sensitive component was found to be the void microstructure, which co-evolves with the loop and dislocation microstructure. These data support the prediction that void swelling will probably be higher in lower-flux fusion devices and PWRs at a given irradiation temperature when compared to irradiations conducted at higher dpa rates in fast reactors.

Okita, Taira; Iwai, Takeo; Sekimura, Naoto; Garner, Francis A.

2002-03-31

130

The displacement cascade in ceramic oxides  

NASA Astrophysics Data System (ADS)

The displacement cascade in ceramic oxides is studied using the atomic scattering methods of Lindhard et al. and the Monte Carlo TRIM methods of Biersack et al. The results concentrate on the effects of cascade energy and material mass ratio. It is seen that the heavy metal atom is preferentially displaced relative to the lighter O atom and that compositional changes can occur on the scale of the cascade.

Parkin, Don. M.

1990-02-01

131

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

132

The Quantum Mechanics of Chemical Kinetics of Homogeneous Gas Phase Reactions II. Approximations for Displacement Reaction between an Atom and a Diatomic Molecule  

Microsoft Academic Search

The quantum mechanics of a displacement reaction: AB+C?A+BC, has been considered and the results have been applied to the reaction: H2+Br?H+HBr at 500°K. The potential energy of the reacting system is based upon the London approximation as modified by Eyring and Polanyi. The absolute rate has been found to be a sensitive function of the coulombic energy fraction; when this

S. Golden; A. M. Peiser

1949-01-01

133

Tip-induced large-area oxide bumps and composition stoichiometry test via atomic force microscopy  

NASA Astrophysics Data System (ADS)

Using atomic force microscope (AFM) tip, local large-area oxide bumps were induced on a native SiO2 layer applied with a static 10 V in an ambient surrounding. It can be seen in the backscattered electron (BE) images that the oxide bumps were SiOx layer, not the native SiO2 layer. Also, the spectra of energy dispersive X-ray spectrometer (EDS) displayed that the oxide bumps contained oxygen more than did the native SiO2 layer, indicating that the O/Si ratio of the oxide bump is greater than two. A comparison of the growth rates of the point oxide protrusions on the oxide bumps and on the native SiO2, can be used to directly determined the composition stoichiometry (the O/Si ratio (=x)) of the oxide bumps.

Lu, Yo-Shan; Wu, Hsin-I.; Wu, Sheng Yun; Ma, Yuan-Ron

2007-09-01

134

RTV 21 Displacements  

SciTech Connect

A seal is needed for the cover of the Nitrogen Test Vessel in order to prevent leakage of the N{sub 2} gas. This seal is to be molded out of RTV 21. In this experiment, the Modulus of Elasticity of the RTV was sought after, and the displacements of the RTV due to various stresses were measured to see if they were large enough to provide a tight seal between the vessel and its cover.

Kurita, C.H.; /Fermilab

1987-02-04

135

Large-field behavior of the LoSurdo-Stark resonances in atomic hydrogen  

SciTech Connect

The Schroedinger equation for atomic hydrogen in a large electric field [ital F] is solved by separation in parabolic coordinates. As [ital F][r arrow][infinity], the scaled field [ital f] that enters the separated equations tends to 0. Thus the large-[ital F] asymptotics depend on the small-[ital f] behavior of the separated equations, each of which in turn is equivalent to a quarticly perturbed two-dimensional anharmonic oscillator. The Bender-Wu branch cuts of the oscillator play a major role in the hydrogen asymptotics. A simple iterative algorithm permits the calculation of the branch points at which two eigenvalues coincide. We have found numerically that, as [ital F][r arrow][infinity], the separation constant [beta][sub 1] returns to the smaller of the unperturbed values [beta][sub 1][sup (0)] or [beta][sub 2][sup (0)]. At the same time, [beta][sub 2] tends to the negative of the smaller value. As the real electric field [ital F] increases from 0 to [infinity], in each case that [beta][sub 1][sup (0)] and [beta][sub 2][sup (0)] are not equal, the trajectory of either [ital f] or [ital e][sup [minus][ital i][pi

Alvarez, G. (Departamento de Fisica Teorica, Facultad de Ciencias Fisicas, Universidad Complutense, 28040 Madrid (Spain)); Silverstone, H.J. (Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218 (United States))

1994-12-01

136

Fabrication of large scale nanostructures based on a modified atomic force microscope nanomechanical machining system  

NASA Astrophysics Data System (ADS)

The atomic force microscope (AFM) tip-based nanomechanical machining has been demonstrated to be a powerful tool for fabricating complex 2D/3D nanostructures. But the machining scale is very small, which holds back this technique severely. How to enlarge the machining scale is always a major concern for the researches. In the present study, a modified AFM tip-based nanomechanical machining system is established through combination of a high precision X-Y stage with the moving range of 100 mm × 100 mm and a commercial AFM in order to enlarge the machining scale. It is found that the tracing property of the AFM system is feasible for large scale machining by controlling the constant normal load. Effects of the machining parameters including the machining direction and the tip geometry on the uniform machined depth with a large scale are evaluated. Consequently, a new tip trace and an increasing load scheme are presented to achieve a uniform machined depth. Finally, a polymer nanoline array with the dimensions of 1 mm × 0.7 mm, the line density of 1000 lines/mm and the average machined depth of 150 nm, and a 20 × 20 polymer square holes array with the scale of 380 ?m × 380 ?m and the average machined depth of 250 nm are machined successfully. The uniform of the machined depths for all the nanostructures is acceptable. Therefore, it is verified that the AFM tip-based nanomechanical machining method can be used to machine millimeter scale nanostructures.

Hu, Z. J.; Yan, Y. D.; Zhao, X. S.; Gao, D. W.; Wei, Y. Y.; Wang, J. H.

2011-12-01

137

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

Microsoft Academic Search

Halogen atoms and oxides are highly reactive and can profoundly affect atmospheric composition. Chlorine atoms can decrease the lifetimes of gaseous elemental mercury and hydrocarbons such as the greenhouse gas methane. Chlorine atoms also influence cycles that catalytically destroy or produce tropospheric ozone, a greenhouse gas potentially toxic to plant and animal life. Conversion of inorganic chloride into gaseous chlorine

Joel A. Thornton; James P. Kercher; Theran P. Riedel; Nicholas L. Wagner; Julie Cozic; John S. Holloway; William P. Dubé; Glenn M. Wolfe; Patricia K. Quinn; Ann M. Middlebrook; Becky Alexander; Steven S. Brown

2010-01-01

138

Large fluctuations in the disassembly rate of microtubules revealed by atomic force microscopy.  

PubMed

Atomic force microscopy (AFM) in situ has been used to observe the cold disassembly dynamics of microtubules at a previously unrealised spatial resolution. Microtubules either electrostatically or covalently bound to aminosilane surfaces disassembled at room temperature under buffer solutions with no free tubulin present. This process was followed by taking sequential tapping-mode AFM images and measuring the change in the microtubule end position as a function of time, with an spatial accuracy down to +/-20nm and a temporal accuracy of +/-1s. As well as giving average disassembly rates on the order of 1-10 tubulin monomers per second, large fluctuations in the disassembly rate were revealed, indicating that the process is far from smooth and linear under these experimental conditions. The surface bound rates measured here are comparable to the rates for GMPCPP-tubulin microtubules free in solution, suggesting that inhibition of tubulin curvature through steric hindrance controls the average, relatively low disassembly rate. The large fluctuations in this rate are thought to be due to multiple pathways in the kinetics of disassembly with differing rate constants and/or stalling due to defects in the microtubule lattice. Microtubules that were covalently bound to the surface left behind the protofilaments covalently cross-linked to the aminosilane via glutaraldehyde during the disassembly process. Further work is needed to quantitatively assess the effects of surface binding on protofibril disassembly rates, reveal any differences in disassembly rates between the plus and minus ends and to enable assembly as well as disassembly to be imaged in the microscope fluid cell in real-time. PMID:12801676

Thomson, Neil H; Kasas, Sandor; Riederer, Beat M; Catsicas, Stefan; Dietler, Giovanni; Kulik, Andrzej J; Forró, László

139

Rotary reactor for atomic layer deposition on large quantities of nanoparticles  

SciTech Connect

Challenges are encountered during atomic layer deposition (ALD) on large quantities of nanoparticles. The particles must be agitated or fluidized to perform the ALD surface reactions in reasonable times and to prevent the particles from being agglomerated by the ALD film. The high surface area of nanoparticles also demands efficient reactant usage because large quantities of reactant are required for the surface reactions to reach completion. The residence time of the reactant in a fluidized particle bed reactor may be too short for high efficiency if the ALD surface reactions have low reactive sticking coefficients. To address these challenges, a novel rotary reactor was developed to achieve constant particle agitation during static ALD reactant exposures. In the design of this new reactor, a cylindrical drum with porous metal walls was positioned inside a vacuum chamber. The porous cylindrical drum was rotated by a magnetically coupled rotary feedthrough. By rotating the cylindrical drum to obtain a centrifugal force of less than one gravitational force, the particles were agitated by a continuous 'avalanche' of particles. In addition, an inert N{sub 2} gas pulse helped to dislodge the particles from the porous walls and provided an efficient method to purge reactants and products from the particle bed. The effectiveness of this rotary reactor was demonstrated by Al{sub 2}O{sub 3} ALD on ZrO{sub 2} particles. A number of techniques including transmission electron microscopy, Fourier transform infrared spectroscopy, and x-ray photoelectron spectroscopy confirmed that the Al{sub 2}O{sub 3} ALD film conformally coats the ZrO{sub 2} particles. Combining static reactant exposures with a very high surface area sample in the rotary reactor also provides unique opportunities for studying the surface chemistry during ALD.

McCormick, J. A.; Cloutier, B. L.; Weimer, A. W.; George, S. M. [Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309 (United States); Department of Chemical and Biological Engineering, University of Colorado, Boulder, Colorado 80309 and Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309 (United States)

2007-01-15

140

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

141

Investigation of Atomic Displacements at a Sigma3 {111} Twin Boundary in BaTiO3 by Means of Phase-Retrieval Electron Microscopy  

Microsoft Academic Search

We applied the technique of focal-series reconstruction in high-resolution electron microscopy for a precise determination of the spacings between atomic columns at a Sigma3 \\\\{111\\\\} twin boundary in perovskite BaTiO3. We succeeded in observing a predicted expansion of the nearest Ti-Ti spacing across the boundary plane and found additionally a contraction of the nearest BaO-BaO spacing. Moreover, the direct visualization

C. L. Jia; A. Thust

1999-01-01

142

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

Microsoft Academic Search

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

D. G. Doran; N. J. Graves

1976-01-01

143

Large-Scale Extended Emission around the Helix Nebula: Dust, Molecules, Atoms, and Ions  

NASA Astrophysics Data System (ADS)

We present new observations of the ionized gas, molecular gas, and cool dust in the Helix Nebula (NGC 7293). The ionized gas is observed in the form of an H? image, which is constructed using images from the Southern H? Sky Survey Atlas. The molecular emission was mapped using the H2 v=1-->0 S(1) line at 2.122 ?m. The far-infrared (FIR) observations were obtained using ISOPHOT on the Infrared Space Observatory. The H? observations are more sensitive than previous measurements and show the huge extent of the Helix, confirming it as a density-bounded nebula and showing previously unseen point-symmetric structures. The H2 observations show that the molecular gas follows the distribution of molecular material shown in previous work. The molecular emission is confined to that part of the nebula seen in the classic optical image. Furthermore, comparison of the H2 emission strength with time-dependent models for photodissociation regions (PDRs) shows that the emission arises from thermal excitation of the hydrogen molecules in PDRs and not from shocks. The FIR observations, at 90 and 160 ?m, represent mostly contributions from thermal dust emission from cool dust grains but include a small contribution from ionized atomic lines. Comparison of the FIR emission with the H? observation shows that the dust and ionized gas are coincident and extend to ~1100" radius. This equates to a spatial radial extent of more than 1 pc (assuming a distance to the Helix of ~200 pc). Assuming that the outer layers of the circumstellar shell have spherical symmetry, radiative transfer modeling of the emission in H? gives a shell mass of ~1.5 Msolar. However, the modeling does not cover the outermost part of the shell (beyond ~600" radius), and therefore this is a lower limit for the shell mass. Moreover, the models suggest the need for very large dust grains, with ~80% of the dust mass in grains larger than 3.5 ?m. Comparison of these new observations with previous observations shows the large-scale stratification of the Helix in terms of ionized gas and dust, as well as the coexistence of molecular species inside the ionized zones, where molecules survive in dense condensations and cometary knots.

Speck, A. K.; Meixner, M.; Fong, D.; McCullough, P. R.; Moser, D. E.; Ueta, T.

2002-01-01

144

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

145

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...

146

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

147

Block Displacement Method Field Demonstration and Specifications.  

National Technical Information Service (NTIS)

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...

T. P. Brunsing

1987-01-01

148

The Atomic-scale Growth of Large-Area Monolayer Graphene on Single-Crystal Copper Substrates  

Microsoft Academic Search

We study the growth and microscopic structure of large-area graphene monolayers, grown on copper single crystals by chemical vapor deposition (CVD) in ultra-high vacuum (UHV). Using atomic-resolution scanning tunneling microscopy (STM), we find that graphene grows primarily in registry with the underlying copper lattice for both Cu(111) and Cu(100). The graphene has a hexagonal superstructure on Cu(111) with a significant

L. Zhao; K. T. Rim; H. Zhou; R. He; T. F. Heinz; A. Pinczuk; G. W. Flynn; A. N. Pasupathy

2010-01-01

149

Large Amplitude Elastic Motions in Proteins from a Single-Parameter, Atomic Analysis  

Microsoft Academic Search

Normal mode analysis (NMA) is a leading method for studying long-time dynamics and elasticity of biomolecules. The method proceeds from complex semiempirical potentials characterizing the covalent and noncovalent interactions between atoms. It is widely accepted that such detailed potentials are essential to the success of NMA's. We show that a single-parameter potential is sufficient to reproduce the slow dynamics in

Monique M. Tirion

1996-01-01

150

Mass Media Displacement and Saturation  

Microsoft Academic Search

This study addresses the contradiction between the theoretical displacement of incumbent media by new media versus empirical evidence of rising consumption of both new and incumbent media. By analyzing 4 years of biannual daypart media consumption surveys, this research reveals trends in the consumer use of advertiser-supported media in the United States. Large gains were seen in new media, such

Jay Newell; Joseph J. Pilotta; John C. Thomas

2008-01-01

151

Local Structure of Displacively Disordered Pyrochlore Dielectrics  

SciTech Connect

Local cation environments in the pyrochlore dielectrics A{sub 2}B{sub 2}O6O' = (Bi,M){sub 2}(M,Nb){sub 2}O{sub 6}O' (M = Zn, Fe) were determined from the extended X-ray absorption fine structure. The A cations and O' ions are displaced from their ideal positions, yielding the effective (4 + 2 + 2) coordination for the A cations. The A-cation displacements are directed toward a pair of the framework O atoms; the specific displacement directions are determined by the nature of the A cations (i.e., Bi, Zn, Fe) and the local Nb/Zn (or Nb/Fe) B-site configurations. Local correlations among the atomic displacements and both [A{sub 4}O'] and [A{sub 2}B{sub 2}O] configurations provide near-ideal bond valence sums for all constituent species in these pyrochlore structures.

Krayzman,V.; Levin, I.; Woicik, J.

2007-01-01

152

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

153

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

Microsoft Academic Search

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

Ashok Chatterjee

1990-01-01

154

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

155

Large-area tungsten diselenide atomic layers on an insulator substrate grown by vapor phase chemical deposition  

NASA Astrophysics Data System (ADS)

Group IV transition metal dichalcogenides such as WS2 and WSe2 are one of attracting material classes which have a physical two dimension of one atomic layer and atomically thin layers like graphene. These materials have interesting features such as an indirect bulk gap makes a transition to a direct band gap in monolayer. Recent research results of FETs showed that a high effective hole mobility of 250 cm^2 /V s with subthreshold swing of 60 mV/dec from an exfoliated monolayer. Indeed it is natural to think that artificial large area synthesis is needed for practical applications. Here we report the large-area tungsten diselenide layers on SiO2 substrate using vapor phase deposition method. Selenium source was evaporated from certain distances to a tungsten thin film on SiO2/Si wafer. Nitrogen gas was flowed during all processes as a carrier gas. Growth was performed at 700 ˜ 900 Celsius degree. The size of atomic tungsten diselenide layers simply depends on a wafer and quartz tube size. Good qualities of selected tungsten diselenide layers were investigated by AFM/EFM, SEM/TEM, and Raman spectroscopy. FET and PL data also will be presented.

Yoo, Kwonjae; Kang, Il-Suk; Park, Yehoon; Ahn, Chi Won; Shin, Jongwoo; Yool Jung, Dae; Cho, Byung Jin; Choi, Sung-Yool; Choi, Hongkyw

2013-03-01

156

Vortices in atomic Bose-Einstein condensates in the large-gas-parameter region  

NASA Astrophysics Data System (ADS)

In this work we compare the results of the Gross-Pitaevskii and modified Gross-Pitaevskii equations with ab initio variational Monte Carlo calculations for Bose-Einstein condensates of atoms in axially symmetric traps. We examine both the ground state and excited states having a vortex line along the z axis at high values of the gas parameter and demonstrate an excellent agreement between the modified Gross-Pitaevskii and ab initio Monte Carlo methods, both for the ground and vortex states.

Nilsen, J. K.; Mur-Petit, J.; Guilleumas, M.; Hjorth-Jensen, M.; Polls, A.

2005-05-01

157

Metastable helium Bose-Einstein condensate with a large number of atoms  

SciTech Connect

We have produced a Bose-Einstein condensate of metastable helium ({sup 4}He*) containing over 1.5x10{sup 7} atoms, which is a factor of 25 higher than previously achieved. The improved starting conditions for evaporative cooling are obtained by applying one-dimensional Doppler cooling inside a magnetic trap. The same technique is successfully used to cool the spin-polarized fermionic isotope ({sup 3}He*), for which thermalizing collisions are highly suppressed. Our detection techniques include absorption imaging, time-of-flight measurements on a microchannel plate detector, and ion counting to monitor the formation and decay of the condensate.

Tychkov, A. S.; Jeltes, T.; McNamara, J. M.; Tol, P. J. J.; Herschbach, N.; Hogervorst, W.; Vassen, W. [Laser Centre Vrije Universiteit, De Boelelaan 1081, 1081 HV Amsterdam (Netherlands)

2006-03-15

158

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

159

Measurement of deep groove structures using a self-fabricated long tip in a large range metrological atomic force microscope  

NASA Astrophysics Data System (ADS)

Metrological atomic force microscopes are widely used in national metrology institutes for measuring step height, lateral pitch and surface roughness. However, the maximum measurable depth or height variation is limited by both the vertical scanning range of the AFM and the tip height and sharpness of the tip at the end of the cantilever. A normal commercial AFM typically has a vertical scanning range less than 10 µm and a tip height of the cantilever only up to 15 µm so that it can be used to detect only relatively smooth surfaces or shallow structures up to several micrometres. To overcome these limitations, we have successfully integrated a long diamond tip of up to 120 µm developed at Namiki Precision Jewel Co., Ltd of Japan onto our large range metrological atomic force microprobe (LRM-AFM) for deep groove structure measurement. The LRM-AFM is based on a nano-measuring machine with a large scanning range of 25 mm in the X and Y axes and 5 mm in the Z axis. This paper describes the long diamond tip fabrication process and especially its application in the LRM-AFM for measuring deep groove structures of a step height of up to 100 µm. In addition, the mechanical quality factor (Q) of the diamond tip micro-cantilever was detected in the system. The results demonstrate that the system is capable of calibrating and measuring the surface structure with deep groove in tens of micrometres.

Wang, S. H.; Tan, S. L.; Xu, G.; Koyama, K.

2011-09-01

160

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

161

Three-body Recombination of Fermionic Atoms with Large Scattering Lengths  

Microsoft Academic Search

The 3-body recombination rate at threshold for fermions with three spin states and large scattering lengths is calculated in the zero-range approximation. The only parameters in this limit are the three scattering lengths and the Efimov parameter, which can be complex valued. Semi-analytic results are obtained for the cases of negative scattering lengths, two of which are equal. The general

Daekyoung Kang; Eric Braaten; Hans-Werner Hammer; Lucas Platter

2009-01-01

162

A New Large Echelle Spectrometer for Measuring Atomic Transition Probabilities of Fe-group Ions  

NASA Astrophysics Data System (ADS)

Accurate atomic transition probabilities for weak lines connected to the ground and low metastable levels of Fe-group ions are needed for elemental abundance studies on metal-poor stars. Metal-poor stars represent the oldest observable stellar generation and offer a direct probe into the early history of nucleosynthesis and the chemical evolution of the Galaxy. Unexplained trends in relative Fe-group abundances, such as [Co/Cr], as a function of metallicity, or [Fe/H], have been observed. These trends may result from a breakdown in the local thermodynamic equilibrium (LTE) approximation used in traditional photosphere models underlying elemental abundance determinations. The ground and low metastable levels of Fe-group ions contain most of the Fe-group material in a stellar photosphere, and thus second spectra lines with low E.P.s are essentially immune to non-LTE effects. To improve lab data on important Fe-group lines we have developed a novel instrument based on a 3 meter focal length vacuum echelle spectrograph combined with an aberration corrected cross dispersion system and a UV sensitive CCD array. This spectrometer is capable of recording both emission and absorption spectra with high resolving power, very broad wavelength coverage, and high signal-to-noise. It is also free from the multiplex noise of a FTS, making it ideally suited for measuring branching fractions of very weak lines. The combination of very accurate branching fractions with radiative lifetimes from time-resolved laser-induced fluorescence will yield accurate absolute transition probabilities of weak second spectra lines with low E.P.s for the Fe-group elements. Instrument design and preliminary results will be presented. Supported by NASA Grant NNX09AL13G.

Wood, Michael; Lawler, J. E.

2012-01-01

163

Point processes and stochastic displacement fields.  

PubMed

The effect of a stochastic displacement field on a statistically independent point process is analyzed. Stochastic displacement fields can be divided into two large classes: spatially correlated and uncorrelated. For both cases exact transformation equations for the two-point correlation function and the power spectrum of the point process are found, and a detailed study of them with important paradigmatic examples is done. The results are general and in any dimension. Particular attention is devoted to the kind of large-scale correlations that can be introduced by the displacement field and to the realizability of arbitrary "superhomogeneous" point processes. PMID:15697458

Gabrielli, Andrea

2004-12-23

164

Tactile suppression of displacement.  

PubMed

In vision, the discovery of the phenomenon of saccadic suppression of displacement has made important contributions to the understanding of the stable world problem. Here, we report a similar phenomenon in the tactile modality. When scanning a single Braille dot with two fingers of the same hand, participants were asked to decide whether the dot was stationary or whether it was displaced from one location to another. The stimulus was produced by refreshable Braille devices that have dots that can be swiftly raised and recessed. In some conditions, the dot was stationary. In others, a displacement was created by monitoring the participant's finger position and by switching the dot activation when it was not touched by either finger. The dot displacement was of either 2.5 mm or 5 mm. We found that in certain cases, displaced dots were felt to be stationary. If the displacement was orthogonal to the finger movements, tactile suppression occurred effectively when it was of 2.5 mm, but when the displacement was of 5 mm, the participants easily detected it. If the displacement was medial-lateral, the suppression effect occurred as well, but less often when the apparent movement of the dot opposed the movement of the finger. In such cases, the stimulus appeared sooner than when the brain could predict it from finger movement, supporting a predictive rather than a postdictive differential processing hypothesis. PMID:20842353

Ziat, Mounia; Hayward, Vincent; Chapman, C Elaine; Ernst, Marc O; Lenay, Charles

2010-09-15

165

The displaced aggression questionnaire.  

PubMed

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to engage in displaced aggression). The trait measure demonstrated good internal consistency and test-retest reliability as well as convergent and discriminant construct validity. Unlike other related personality measures, trait displaced aggression significantly predicted indirect indicators of real-world displaced aggression (i.e., self-reported domestic abuse and road rage) as well as laboratory displaced aggression in 2 experiments. PMID:16784350

Denson, Thomas F; Pedersen, William C; Miller, Norman

2006-06-01

166

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

167

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

168

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

2011-05-16

169

Internal Displacement Monitoring Centre  

NSDL National Science Digital Library

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

170

Influence of qubit displacements on quantum logic operations in a silicon-based quantum computer with constant interaction  

SciTech Connect

The errors caused by qubit displacements from their prescribed locations in an ensemble of spin chains are estimated analytically and calculated numerically for a quantum computer based on phosphorus donors in silicon. We show that it is possible to polarize (initialize) the nuclear spins even with displaced qubits by using controlled-NOT gates between the electron and nuclear spins of the same phosphorus atom. However, a controlled-NOT gate between the displaced electron spins is implemented with large error because of the exponential dependence of exchange interaction constant on the distance between the qubits. If quantum computation is implemented on an ensemble of many spin chains, the errors can be small if the number of chains with displaced qubits is small.

Kamenev, D. I.; Berman, G. P. [Theoretical Division, T-13, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Tsifrinovich, V. I. [Department of Physics, Polytechnic University, Brooklyn, New York 11201 (United States)

2006-10-15

171

Kinematics Problem: Displacement  

NSDL National Science Digital Library

A bowling ball is lifted from rest onto a shelf by an external agent (position is in meters and time is in seconds). Rank the paths by the displacement of the bowling ball during the animations (greatest first).

Christian, Wolfgang; Belloni, Mario

2006-01-20

172

Precision Displacement Mechanism (PDM).  

National Technical Information Service (NTIS)

A mechanism designed to fulfill the requirements of the Precision Displacement Mechanism (PDM) for the Far Infrared and Submillimeter Space Telescope (FIRST) antenna is described. The PDM function is to perform the fine adjustment of the position of the m...

J. I. Bueno F. Delcampo P. Coste

1993-01-01

173

Electron displacement damage in cobalt in a high voltage electron microscope  

Microsoft Academic Search

If a lattice atom receives, as the result of a collision with an incident projectile, an energy in excess of the displacement threshold energy Ed, then it is displaced from its lattice site, thereby creating at least one vacancy and one interstitial atom. High voltage electron microscopes with beam energies sufficient to transfer to a lattice atom an energy E>

L. M. Howe

1970-01-01

174

Variance and covariance of accumulated displacement estimates.  

PubMed

Tracking large deformations in tissue using ultrasound can enable the reconstruction of nonlinear elastic parameters, but poses a challenge to displacement estimation algorithms. Such large deformations have to be broken up into steps, each of which contributes an estimation error to the final accumulated displacement map. The work reported here measured the error variance for single-step and accumulated displacement estimates using one-dimensional numerical simulations of ultrasound echo signals, subjected to tissue strain and electronic noise. The covariance between accumulation steps was also computed. These simulations show that errors due to electronic noise are negatively correlated between steps, and therefore accumulate slowly, whereas errors due to tissue deformation are positively correlated and accumulate quickly. For reasonably low electronic noise levels, the error variance in the accumulated displacement estimates is remarkably constant as a function of step size, but increases with the length of the tracking kernel. PMID:23493610

Bayer, Matthew; Hall, Timothy J

2013-04-01

175

Atomistic Simulation of Displacement Cascades in Zircon  

SciTech Connect

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

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

2002-05-06

176

Large-area vapor-phase growth and characterization of MoS(2) atomic layers on a SiO(2) substrate.  

PubMed

Atomic-layered MoS(2) is synthesized directly on SiO(2) substrates by a scalable chemical vapor deposition method. The large-scale synthesis of an atomic-layered semiconductor directly on a dielectric layer paves the way for many facile device fabrication possibilities, expanding the important family of useful mono- or few-layer materials that possess exceptional properties, such as graphene and hexagonal boron nitride (h-BN). PMID:22334392

Zhan, Yongjie; Liu, Zheng; Najmaei, Sina; Ajayan, Pulickel M; Lou, Jun

2012-02-15

177

Laser spectroscopic observation and large-scale configuration-interaction calculation of doubly excited msns 1Se states of Ca atoms  

Microsoft Academic Search

With multistep laser excitation via 4sn's Rydberg states, doubly excited msns 1Se states (m=6, 9<=n<=20 m=7, 9<=n<=20 m=10, 10<=n<=20 except n=11) of Ca atoms have been observed, and their energy levels have been obtained. The large-scale configuration-interaction calculation for Ca atoms has also been executed using a discrete two-electron basis set, in which a frozen Ca2+ core is assumed and

Norio Morita; Toshifumi Suzuki

1990-01-01

178

Displacement of large-scale open solar magnetic fields from the zone of active longitudes and the heliospheric storm of November 3-10, 2004: 2. "Explosion" of singularity and dynamics of sunspot formation and energy release  

NASA Astrophysics Data System (ADS)

A more detailed scenario of one stage (August-November 2004) of the quasibiennial MHD process "Origination ... and dissipation of the four-sector structure of the solar magnetic field" during the decline phase of cycle 23 has been constructed. It has been indicated that the following working hypothesis on the propagation of an MHD disturbance westward (in the direction of solar rotation) and eastward (toward the zone of active longitudes) with the displacement of the large-scale open solar magnetic field (LOSMF) from this zone can be constructed based on LOSMF model representations and data on sunspot formation, flares, active filaments, and coronal ejections as well as on the estimated contribution of sporadic energy release to the flare luminosity and kinetic energy of ejections: (1) The "explosion" of the LOSMF singularity and the formation in the explosion zone of an anemone active region (AR), which produced the satellite sunspot formation that continued west and east of the "anemone," represented a powerful and energy-intensive source of MHD processes at this stage. (2) This resulted in the origination of two "governing" large-scale MHD processes, which regulated various usual manifestations of solar activity: the fast LOSMF along the neutral line in the solar atmosphere, strongly affecting the zone of active longitudes, and the slow LOSMF in the outer layers of the convection zone. The fronts of these processes were identified by powerful (about 1031 erg) coronal ejections. (3) The collision of a wave reflected from the zone of active longitudes with the eastern front of the hydromagnetic impulse of the convection zone resulted in an increase in LOSMF magnetic fluxes, origination of an active sector boundary in the zone of active longitudes, shear-convergent motions, and generation and destabilization of the flare-productive AR 10696 responsible for the heliospheric storm of November 3-10, 2004.

Ivanov, K. G.

2010-12-01

179

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

180

Global displacement models 1  

Microsoft Academic Search

An introduction into global displacement models is presented. The local dynamical equation in the Eulerian and the Lagrangean description is reviewed with reference to stress tensors of type Cauchy, Piola, Kirchhoff and Finger. Constitutive equations for linear viscoelastic material with isotropic prestress are discussed. The role of frame velocity and frame acceleration or of Coriolis acceleration, Euler acceleration (gyroscopic or

E. W. Grafarend

1982-01-01

181

Character displacement in Hydrobia  

Microsoft Academic Search

Fenchel's study of size variation in Hydrobiid snails in the Limfjord, Denmark, provides one of the most convincing cases of ecological character displacement available. In order to assess the generality of the phenomena within the Hydrobia genus, allopatric and sympatric Hydrobia ventrosa, H. neglecta and H. ulvae were collected from 24 coastal sites around Eastern England in July and October,

A. J. Cherrill; R. James

1987-01-01

182

Romanticism displaced and placeless  

Microsoft Academic Search

Displacement, deriving mainly from the circumstances of the first modern world war, is an abiding notion in European Romanticism. It can take the form of a fragmentation of psychic identity through loss of nationality, as we find in Ugo Foscolo, or of the exile’s split between nationalist identities, as exemplified by Germaine de Staël’s Corinne. But in the literature of

Stuart Curran

2009-01-01

183

Tidal station displacements  

Microsoft Academic Search

Theoretical modeling of the station displacements produced by tidal deformations of the Earth due to lunisolar gravitational forces is a necessary part of the analysis of space geodetic data. To attain the accuracies demanded by the precision of the data, a generalized version of the Love number formalism has to be used wherein the classical Love and Shida numbers are

P. M. Mathews; V. Dehant; John M. Gipson

1997-01-01

184

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

185

Experimental measurement of local displacement and chemical pair correlations in crystalline solid solutions.  

National Technical Information Service (NTIS)

Measurement of near-neighbor atomic arrangements in crystalline solid solutions is well established and provides meaningful values for chemical preference of atoms for their near neighbors to beyond the first ten neighboring shells. Static displacements (...

C. L. Sparks G. E. Ice J. L. Robertson L. B. Shaffer

1993-01-01

186

Displaced patella fractures.  

PubMed

Displaced patella fractures often result in disruption of the extensor mechanism of the knee. An intact extensor mechanism is a requirement for unassisted gait. Therefore, operative treatment of the displaced patella fracture is generally recommended. The evaluation of the patella fracture patient includes examination of extensor mechanism integrity. Operative management of patella fractures normally includes open reduction with internal fixation, although partial patellectomy is occasionally performed, with advancement of quadriceps tendon or patellar ligament to the fracture bed. Open reduction with internal fixation has historically been performed utilizing anterior tension band wiring, although comminution of the fracture occasionally makes this fixation construct inadequate. Supplementation or replacement of the tension band wire construct with interfragmentary screws, cerclage wire or suture, and/or plate-and-screw constructs may add to the stability of the fixation construct. Arthrosis of the patellofemoral joint is very common after healing of patella fractures, and substantial functional deficits may persist long after fracture healing has occurred. PMID:23966286

Della Rocca, Gregory J

2013-08-21

187

The Displaced Aggression Questionnaire  

Microsoft Academic Search

Previous measures of aggressive personality have focused on direct aggression (i.e., retaliation toward the provoking agent). An original self-report measure of trait displaced aggression is presented. Exploratory and confirmatory factor analyses provided support for a 3-factor conceptualization of the construct. These analyses identified an affective dimension (angry rumination), a cognitive dimension (revenge planning), and a behavioral dimension (general tendency to

Thomas F. Denson; William C. Pedersen; Norman Miller

2006-01-01

188

Above Water: Buoyancy & Displacement  

NSDL National Science Digital Library

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

Jersey, New; Center, Liberty S.; Coalition, New J.

2006-01-01

189

Large projects at the accelerator mass spectrometry facility at the China Institute of Atomic Energy during the last 12 years  

NASA Astrophysics Data System (ADS)

Progress made by the Accelerator Mass Spectrometry (AMS) facility at the China Institute of Atomic Energy (CIAE) since 1999 is reported in terms of system upgrades, exploration with other long-lived isotopes, advancements in methodology, and new applications.

Shan, Jiang; Ming, He; Kejun, Dong; Yinggen, Ouyang; Yueming, Hu; Qubo, You; Yiwen, Bao; Jian, Yuan; Wei, Wang; Chaoli, Li; Shaoyong, Wu

2013-01-01

190

Digital Fiber Optic Displacement Sensors.  

National Technical Information Service (NTIS)

A digital fiber optic displacement sensor using a Mach-Zehnder interferometer was tested. The theoretical sensitivity of digital interferometer displacement sensors, and the dual polarization method are presented. Experimental results show that interferom...

N. Fuerstenau

1987-01-01

191

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

192

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

193

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

194

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.

195

Transferring cold atoms in double magneto-optical trap by a continuous-wave transfer laser beam with large red detuning.  

PubMed

A novel scheme of transferring cold atoms in a double magneto-optical trap (MOT) system has been experimentally demonstrated. Cold cesium atoms trapped in a vapor-cell MOT are efficiently transferred to an ultrahigh-vacuum (UHV) MOT by a continuous-wave divergent Gaussian transfer laser beam. When large red detuning and moderate intensity are adopted for the transfer laser beam, enhancement of the recapturing of atoms in the UHV MOT is clearly observed. Using the divergent transfer laser beam (diameter of approximately 1.60 mm in the vapor-cell MOT region) with typical power of approximately 20.2 mW, up to approximately 85% of transfer efficiency is obtained when the frequency detuning is set to around -1.2 GHz, and it is not sensitive to small detuning variation. This transfer is much efficient compared with that in the case of continuous-wave near-resonance weak transfer laser beam (typical power of order of approximately 100 microW and typical frequency detuning of approximately-10 MHz) which is normally used in double-MOT experiment. The enhancement is ascribed to the guiding effect on cold atomic flux by transverse dipole potential of the large red-detuned transfer laser beam. PMID:19123554

Wang, Junmin; Wang, Jing; Yan, Shubin; Geng, Tao; Zhang, Tiancai

2008-12-01

196

Bonding study of TiC and TiN. I. High-precision x-ray-diffraction determination of the valence-electron density distribution, Debye-Waller temperature factors, and atomic static displacements in TiC0.94 and TiN0.99  

NASA Astrophysics Data System (ADS)

Single-crystal, high-precision, high-resolution x-ray-diffraction measurements of the substoichiometric refractory compounds TiC and TiN have been performed with AgK? radiation. Severe anisotropic general extinction affects the intense low-order reflections. Inhomogeneity in the mosaic spread and domain size produces small but significant differences between reflection and antireflection for the same plane of diffraction. These effects have been modeled and refined together with a scale factor, isotropic thermal parameters, a population parameter of the nonmetal site, the amplitude of metal-atom static displacements around nonmetal vacancies, and an atomic model which includes occupancy factors of the separate orbital contributions of the valence electrons combined with ? expansion-contraction parameters. At convergence, the ``agreement indices'' (or ``reliability factors'') were R=0.0025 for TiC0.94 and R=0.0023 for TiN0.99. The refined population parameters indicate a chemical composition of TiC0.939(9) and TiN0.99(2). The mean-square amplitudes of thermal vibrations, Ti=0.002 38(2) AṦ, C=0.003 35(8) AṦ, Ti=0.002 94(1) AṦ, and N=0.003 08(12) AṦ are consistent with the respective atomic masses. 36% of the metal atoms in TiC0.94 are involved in a relaxation around the nonmetal vacancies, being displaced from their sublattice sites by 0.097(2) Å along [100]. No evidence for static displacements was found in TiN0.99. The valence-electron density distribution can be described satisfactorily in terms of deformed atoms. No buildup of charge density occurs between atomic sites. Our analysis, similar to a Mulliken partitioning, shows first that ionicity is important, with a charge transfer from the metal to the nonmetal of [2.1(4)]e in the carbide and [1.9(4)]e in the nitride, and secondly that the charge asphericity around the metal atoms is larger in the former than in the latter, while no departure from spherical symmetry is observed around the nonmetal atoms. The titanium 3d electrons can be split into a spherical shell that contains [1.27(6)]e plus an excess of [0.24(5)]e shared by two orbitals of eg symmetry in the carbide and conversely into a spherical shell that contains [0.88(11)]e plus an excess of [0.12(9)]e shared by three orbitals of t2g symmetry in the nitride. This suggests that the metal-to-metal bonding is similar in TiC and in TiN while the metal-to-nonmetal bonding is greater in TiC than in TiN.

Dunand, A.; Flack, H. D.; Yvon, K.

1985-02-01

197

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

SciTech Connect

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

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

1986-12-01

198

Insuring Displaced Workers: Human Capital Losses and Severance Pay Design  

Microsoft Academic Search

Displaced workers, especially long tenured workers, face large human capital losses. Private firms frequently offer insurance against this threat in the form of severance pay – scheduled benefits linked in expectation to the worker’s human capital loss. We explore this linkage, first reviewing common severance benefit algorithms and then comparing them with simple models of capitalized job displacement losses on

Shuaizhang Feng; Donald O. Parsons

2006-01-01

199

Tourist displacement in two South African sport mega-events  

Microsoft Academic Search

Crowding-out (or displacement) of non-event visitors has received little attention in the literature on the impact of sports events, largely because it cannot be measured accurately. This paper discusses such effects in conceptual terms and reports the results of an analysis of data on tourist arrivals in South Africa aimed at estimating the displacement effects of two sports events held

Johan Fourie; Krige Siebrits; Karly Spronk

2011-01-01

200

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

1986-01-01

201

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

Microsoft Academic Search

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

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

1999-01-01

202

Protein–water displacement distributions  

Microsoft Academic Search

The statistical properties of fast protein–water motions are analyzed by dynamic neutron scattering experiments. Using isotopic exchange, one probes either protein or water hydrogen displacements. A moment analysis of the scattering function in the time domain yields model-independent information such as time-resolved mean square displacements and the Gauss-deviation. From the moments, one can reconstruct the displacement distribution. Hydration water displays

Wolfgang Doster; Marcus Settles

2005-01-01

203

MRI of displaced meniscal fragments.  

PubMed

A torn meniscus frequently requires surgical fixation or debridement as definitive treatment. Meniscal tears with associated fragment displacement, such as bucket handle and flap tears, can be difficult to recognize and accurately describe on MRI, and displaced fragments can be challenging to identify at surgery. A displaced meniscal fragment can be obscured by synovium or be in a location not usually evaluated at arthroscopy. We present a pictorial essay of meniscal tears with displaced fragments in patients referred to a pediatric hospital in order to increase recognition and accurate interpretation by the radiologist, who in turn can help assist the surgeon in planning appropriate therapy. PMID:21863288

Dunoski, Brian; Zbojniewicz, Andrew M; Laor, Tal

2011-08-24

204

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

NASA Astrophysics Data System (ADS)

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 constant for lifetime degradation in SiC is lower than that for GaAs by more than three orders of magnitude, indicating a greatly superior resistance of SiC to displacement damage in most radiation environments.

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

1991-12-01

205

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

Microsoft Academic Search

The influence of negative-energy states (NES) on forbidden magnetic-dipole\\u000a$ns_{1\\/2}-(n+1)s_{1\\/2}$ transitions in alkali-metal atoms is investigated. We\\u000afind that the NES contributions are significant in almost all cases and for\\u000arubidium reduce the transition rate by a factor of 8. We tabulate\\u000amagnetic-dipole (M_1) transition amplitudes for the alkalis. Our M_1 value for\\u000acesium, where accurate measurements are available, differs

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

1999-01-01

206

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

NASA Astrophysics Data System (ADS)

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

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

2009-06-01

207

CHARACTER DISPLACEMENT IN POLYPHENIC TADPOLES  

Microsoft Academic Search

Biologists have long known that closely related species are often phenotypically different where they occur together, but are indistinguishable where they occur alone. The causes of such character displacement are controversial, however. We used polyphenic spadefoot toad tadpoles (Spea bombifrons and S. multiplicata) to test the hypothesis that character displacement evolves to minimize competition for food. We also sought to

David W. Pfennig; Peter J. Murphy

2000-01-01

208

Response of CsI(Tl) scintillators over a large range in energy and atomic number of ions. Part II: calibration and identification in the INDRA array  

NASA Astrophysics Data System (ADS)

The light output of the 324 CsI(Tl) scintillators of INDRA has been measured over large ranges in energy: 1-80AMeV and in atomic number of incident ions: /Z=1-60. An analytical expression for the non-linear total light response as a function of the energy and the identity of the ion is developed. It depends on four parameters. For three of them, connected to CsI(Tl) intrinsic characteristics, fixed values are proposed. Two applications are presented: energy calibration and fragment identification in telescopes using a CsI(Tl) crystal as residual energy detector.

Pârlog, M.; Borderie, B.; Rivet, M. F.; T?b?caru, G.; Chbihi, A.; Elouardi, M.; Le Neindre, N.; Lopez, O.; Plagnol, E.; Tassan-Got, L.; Auger, G.; Bacri, Ch. O.; Bellaize, N.; Bocage, F.; Bougault, R.; Bouriquet, B.; Brou, R.; Buchet, P.; Charvet, J. L.; Colin, J.; Cussol, D.; Dayras, R.; Demeyer, A.; Doré, D.; Durand, D.; Frankland, J. D.; Galichet, E.; Genouin-Duhamel, E.; Gerlic, E.; Hudan, S.; Guinet, D.; Lautesse, P.; Lavaud, F.; Laville, J. L.; Lecolley, J. F.; Leduc, C.; Legrain, R.; Louvel, M.; Maskay, A. M.; Nalpas, L.; Normand, J.; Péter, J.; Rosato, E.; Saint-Laurent, F.; Steckmeyer, J. C.; Tamain, B.; Tirel, O.; Vient, E.; Volant, C.; Wieleczko, J. P.

2002-04-01

209

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

210

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

SciTech Connect

This paper reports on the frequency response of silicon carbide (SiC) light-emitting diodes that have 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 {plus minus} 7 keV, corresponding to an atomic displacement threshold energy, E{sub d}, of 21.8 {plus minus} 1.5 eV for the carbon atom. No evidence was seen of persistent damage due to displacement of silicon atoms. For electrons of energies greater than 0.5 MeV, the damage constant for lifetime degradation in SiC is lower than that for GaAs by more than three orders of magnitude, indicating a greatly superior resistance of SiC to displacement damage in most radiation environments.

Barry, A.L. (Communication Research Center, Ottawa (CA)); Lehmann, B.; Fritsch, D.; Braunig, D. (Hahn-Meitner-Inst. Berlin GmbH, Berlin (DE))

1991-12-01

211

Projected atomic structure of a large-angle (001). sigma. = 5 (theta = 36. 9/sup 0/) twist boundary in gold: diffraction analysis and theoretical predictions  

SciTech Connect

The projected atomic structure of a large angle (001) ..sigma.. = 5 (theta = 36.9/sup 0/) twist boundary in Au was determined using x-ray diffraction techniques. The extra reflections resulting from the periodic structure of the boundary were studied using synchrotron radiation. The observed structure factor rules are consistent with the boundary existing in the exact (no translation away from) coincidence configuration. The projected structure was determined using a variable coordinate and reliability factor analysis which was simplified by the low value of ..sigma.., the boundary symmetry and the assumption of a thin boundary region. The structure thus determined consists of groups of atoms which have undergone large rotations about 0-elements in the planes immediately adjacent to the boundary. The structure is made up of separate patches of median fcc structure in analogy with small angle boundaries. Various structures calculated by computer relaxation techniques using interatomic potentials are also presented and compared with the diffraction results. These structures also show rotational relaxations about 0-elements but the degree of the rotation is much smaller than was determined by diffraction leading to a distortion of the median fcc structure. Consequently, there is only limited correspondence between the computer results and experimental observations.

Budai, J.; Bristowe, P.D.; Sass, S.L.

1982-09-01

212

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

213

Community-wide character displacement in barnacles: a new perspective for past observations  

Microsoft Academic Search

We tested for community-wide character displacement of feeding leg length and shell morphology in two barnacle communities on the west coast of North America (southern California, USA and Vancouver Island, Canada). Neither community exhibited even displacement in shell morphology. Both barnacle communities, however, exhibited remarkably evenly displaced feeding leg length, despite large differences in geography and species composition (between the

Kerry B. Marchinko; Michael T. Nishizaki; K. C. Burns

2004-01-01

214

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

215

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

216

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

217

Displaced apophyseal olecranon fracture in a healthy child.  

PubMed

Olecranon apophyseal fractures in children are uncommon. The bulk of these injuries are nondisplaced and therefore can be treated nonoperatively. Few published reports of children with displaced fractures of the olecranon apophysis exist, and the large majority of reports describe children with osteogenesis imperfecta. We report our experience with the case of an 11-year-old, healthy, male patient without osteogenesis imperfecta who sustained a displaced olecranon apophyseal fracture during a fall. PMID:18274017

Carney, Joseph R; Fox, David; Mazurek, Michael T

2007-12-01

218

Asymptomatic Motor Cortex Displacement due to a Giant Arachnoid Cyst  

Microsoft Academic Search

Cerebral lesions are held to induce plastic changes of the brain. Less well established, however, is how much space-occupying brain lesions may only displace functional representations. In a 66-year-old man we show, by means of functional magnetic resonance imaging and transcranial magnetic stimulation, a profound displacement of the motor cortex due to a large asymptomatic arachnoid cyst. Thus, the chronically

J. Nickel; S. Jörgens; P. Bussfeld; R. J. Seitz

2008-01-01

219

Competitive adsorption, displacement, and transport of organic matter on iron oxide: II. Displacement and transport  

SciTech Connect

The competitive interactions between organic matter compounds and mineral surfaces are poorly understood, yet these interactions may play a significant role in the stability and co-transport of mineral colloids and/or environmental contaminants. In this study, the processes of competitive adsorption, displacement, and transport of Suwannee River natural organic matter (SR-NOM) are investigated with several model organic compounds in packed beds of iron oxide-coated quartz columns. Results demonstrated that strongly-binding organic compounds are competitively adsorbed and displace those weakly-bound organic compounds along the flow path. Among the four organic compounds studied, polyacrylic acid (PAA) appeared to be the most competitive, whereas SR-NOM was more competitive than phthalic and salicylic acids. A diffuse adsorption and sharp desorption front (giving an appearance of irreversible adsorption) of the SR-NOM breakthrough curves are explained as being a result of the competitive time-dependent adsorption and displacement processes between different organic components within the SR-NOM. The stability and transport of iron oxide colloids varied as one organic component competitively displaces another. Relatively large quantities of iron oxide colloids are transported when the more strongly-binding PAA competitively displaces the weakly-binding SR-NOM or when SR-NOM competitively displaces phthalic and salicylic acids. Results of this study suggest that the chemical composition and hence the functional behavior of NOM (e.g., in stabilizing mineral colloids and in complexing contaminants) can change along its flow path as a result of the dynamic competitive interactions between heterogeneous NOM subcomponents. Further studies are needed to better define and quantify these NOM components as well as their roles in contaminant partitioning and transport. 37 refs., 10 figs.

Gu, B; Mehlhorn, T.L.; Liang, Liyuan [Oak Ridge National Lab., TN (United States)] [and others

1996-08-01

220

MOLECULAR AND ATOMIC GAS IN THE LARGE MAGELLANIC CLOUD. II. THREE-DIMENSIONAL CORRELATION BETWEEN CO AND H I  

SciTech Connect

We compare the CO (J = 1-0) and H I emission in the Large Magellanic Cloud in three dimensions, i.e., including a velocity axis in addition to the two spatial axes, with the aim of elucidating the physical connection between giant molecular clouds (GMCs) and their surrounding H I gas. The CO J = 1-0 data set is from the second NANTEN CO survey and the H I data set is from the merged Australia Telescope Compact Array (ATCA) and Parkes Telescope surveys. The major findings of our analysis are as follows: (1) GMCs are associated with an envelope of H I emission, (2) in GMCs [average CO intensity] propor to [average H I intensity]{sup 1.1+}-{sup 0.1}, and (3) the H I intensity tends to increase with the star formation activity within GMCs, from Type I to Type III. An analysis of the H I envelopes associated with GMCs shows that their average line width is 14 km s{sup -1} and the mean density in the envelope is 10 cm{sup -3}. We argue that the H I envelopes are gravitationally bound by GMCs. These findings are consistent with a continual increase in the mass of GMCs via H I accretion at an accretion rate of 0.05 M{sub sun} yr{sup -1} over a timescale of 10 Myr. The growth of GMCs is terminated via dissipative ionization and/or stellar-wind disruption in the final stage of GMC evolution.

Fukui, Y.; Kawamura, A.; Murai, M.; Iritani, H.; Mizuno, N.; Mizuno, Y.; Onishi, T.; Muller, E. [Department of Astrophysics, Nagoya University, Furocho, Chikusaku, Nagoya 464-8602 (Japan); Wong, T. [Astronomy Department, University of Illinois, 1002 W. Green Street, Urbana, IL 61801 (United States); Hughes, A. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122 (Australia); Ott, J. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States); Staveley-Smith, L. [School of Physics M013, University of Western Australia, Crawley, WA 6009 (Australia); Kim, S., E-mail: fukui@a.phys.nagoya-u.ac.j, E-mail: kawamura@a.phys.nagoya-u.ac.j [Department of Astronomy and Space Science, Sejong University, KwangJin-gu, KunJa-dong 98, Seoul 143-747 (Korea, Republic of)

2009-11-01

221

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

222

Molecular Dynamics Simulations of Displacement Cascades in Single and Polycrystalline Zirconia  

SciTech Connect

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

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

2009-03-10

223

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

224

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

225

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

226

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

227

Multiple displacement motor driven power drive unit  

Microsoft Academic Search

A multiple displacement motor driven power drive unit having two separate hydraulic systems each with a variable displacement hydraulic motor having its output connected to a torque summing gear train. A control provides for operation of one or the other of the motors at full displacement while the other motor is at zero displacement and free-wheels. There is a manual

Burandt

1985-01-01

228

Reassociation rate limited displacement of DNA strands by branch migration.  

PubMed Central

Large branched DNA structures are constructed by two-step reassociation of separated complementary strands from restriction fragments of different lengths. The displacement of DNA strands initially annealed to longer complementary DNA sequences, a process mediated by branch migration, is very rapid and has thus far been followed only under conditions which are second order, DNA reassociation rate limiting. The average lifetime of branched DNA leading to displacement of 1.6 Kb strands is estimated to be less than 10 seconds under conditions of DNA reassociation, Tm-25 degrees C. Several DNA-binding drugs, including intercalating dyes, have been tested to determine their influence, if any, on the kinetics of DNA strand displacements by branch migration. Only actinomycin D was found to have significant effect under the conditions we have described. The kinetics of the strand displacement in the presence of low concentrations of actinomycin D remain second order and slower rate of strand displacement must be attributed to decreased rate of reassociation of DNA strands to form the branched intermediates. Consideration is given to the potential manipulation of DNA structures at site-directed branches and the limitations due to rapid strand displacements. The feasibility of constructing sufficiently large branched DNA regions to approach first order, branch migration rate limiting kinetics is also discussed. Images

Green, C; Tibbetts, C

1981-01-01

229

Dedicated ultrasound speckle tracking to study tendon displacement  

NASA Astrophysics Data System (ADS)

Ultrasound can be used to study tendon and muscle movement. However, quantization is mostly based on manual tracking of anatomical landmarks such as the musculotendinous junction, limiting the applicability to a small number of muscle-tendon units. The aim of this study is to quantify tendon displacement without employing anatomical landmarks, using dedicated speckle tracking in long B-mode image sequences. We devised a dedicated two-dimensional multikernel block-matching scheme with subpixel accuracy to handle large displacements over long sequences. Images were acquired with a Philips iE33 with a 7 MHz linear array and a VisualSonics Vevo 770 using a 40 MHz mechanical probe. We displaced the flexor digitorum superficialis of two pig cadaver forelegs with three different velocities (4,10 and 16 mm/s) over 3 distances (5, 10, 15 mm). As a reference, we manually determined the total displacement of an injected hyperechogenic bullet in the tendons. We automatically tracked tendon parts with and without markers and compared results to the true displacement. Using the iE33, mean tissue displacement underestimations for the three different velocities were 2.5 +/- 1.0%, 1.7 +/- 1.1% and 0.7 +/- 0.4%. Using the Vevo770, mean tissue displacement underestimations were 0.8 +/- 1.3%, 0.6 +/- 0.3% and 0.6 +/- 0.3%. Marker tracking displacement underestimations were only slightly smaller, showing limited tracking drift for non-marker tendon tissue as well as for markers. This study showed that our dedicated speckle tracking can quantify extensive tendon displacement with physiological velocities without anatomical landmarks with good accuracy for different types of ultrasound configurations. This technique allows tracking of a much larger range of muscle-tendon units than by using anatomical landmarks.

Korstanje, Jan-Wiebe H.; Selles, Ruud W.; Stam, Henk J.; Hovius, Steven E. R.; Bosch, Johan G.

2009-02-01

230

Photoionization of hydrogen atoms by coherent intense high-frequency short laser pulses: Direct propagation of electron wave packets on large spatial grids  

NASA Astrophysics Data System (ADS)

The time-dependent Schrödinger equation for the hydrogen atom and its interaction with coherent intense high-frequency short laser pulses is solved numerically exactly by propagating single-electron wave packets. Thereby, the wave function is followed in space and time for times longer than the pulse duration. Results are explicitly shown for 3 and 10 fs pulses. Particular attention is paid to identifying the effect of dynamic interference of photoelectrons emitted with the same kinetic energy at different times in the rising and falling sides of the pulse as predicted by Demekhin and Cederbaum [Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.108.253001 108, 253001 (2012)]. In order to be able to see the dynamic interference pattern in the computed electron spectra, the photoelectron wave packet has to be propagated over long distances. Clearly, the complex absorption potentials often employed to compute the spectra of emitted particles cannot be used to detect dynamic interference. For the considered high-frequency pulses of 3 and 10 fs duration, this requires enormously large spatial grids. The photoionization and above-threshold ionization spectra presently computed are found to exhibit pronounced dynamic interference patterns. The patterns are in very good agreement with previously published results on the photoionization spectra, where available, which were computed using a completely different method, thus supporting the previously made assumption that the above-threshold ionization processes are very weak for the considered pulse intensities and high carrier frequency. The quiver motion in space and time of a free electron in strong laser pulses is also investigated numerically. Finally, a discussion is presented of how fast the atom is ionized by an intense pulse.

Demekhin, Philipp V.; Hochstuhl, David; Cederbaum, Lorenz S.

2013-08-01

231

Oxygen atom transfer reactions of iridium and osmium complexes: theoretical study of characteristic features and significantly large differences between these two complexes.  

PubMed

Oxygen atom transfer reaction between ML(3)=O and ML(3) (L = 2,4,6-trimethylphenyl (Mes) for M = Ir and L = 2,6-diisopropylphenylimide (NAr) for M = Os) was theoretically investigated by DFT method. The optimized geometry of (Mes)(3)Ir-O-Ir(Mes)(3) agrees well with the experimental one, although those of (CH(3))(3)Ir-O-Ir(CH(3))(3) and Ph(3)Ir-O-IrPh(3) are much different from the experimental one of the Mes complex. These results indicate that the bulky ligand plays important roles to determine geometry of the mu-oxo dinuclear Ir complex. Theoretical study of the real systems presents clear pictures of these oxygen atom transfer reactions, as follows: In the Ir reaction system, (i) the mu-oxo bridged dinuclear complex is more stable than the infinite separation system in potential energy surface, indicating this is incomplete oxygen atom transfer reaction which does not occur at very low temperature, (ii) unsymmetrical transition state is newly found, in which one Ir-O distance is longer than the other one, (iii) unsymmetrical local minimum is also newly found between the transition state and the infinite separation system, and (iv) activation barrier (E(a)) is very small. In the Os reaction system, (v) the transition state is symmetrical, while no intermediate is observed unlike the Ir reaction system, and (vi) E(a) is very large. These results are consistent with the experimental results that the reaction rapidly occurs in the Ir system but very slowly in the Os system, and that the mu-oxo bridged dinuclear intermediate is detected in the Ir system but not in the Os system. To elucidate the reasons of these differences between Ir and Os systems, the E(a) value is decomposed into the nuclear and electronic factors. The former is the energy necessary to distort ML(3) and ML(3)=O moieties from their equilibrium geometries to those in the transition state. The latter depends on donor-acceptor interaction between ML(3)=O and ML(3). The nuclear factor is much larger in the Os system than in the Ir system and it contributes to about 70% of the difference in E(a). The energy gap between the donor orbital of ML(3) and the acceptor orbital of ML(3)=O is much larger in the Os system than in the Ir system, which also contributes to the lower E(a) value of the Ir system than that of the Os system. PMID:19670885

Ishikawa, Atsushi; Nakao, Yoshihide; Sato, Hirofumi; Sakaki, Shigeyoshi

2009-09-01

232

Sectoral Change and Worker Displacement.  

National Technical Information Service (NTIS)

The research addresses dislocated worker problems and provides a comprehensive view of worker displacement and its role in the evolution of unemployment patterns over the past twenty-five years. The first part of the study measures a aggregate rate of wor...

R. Topel K. Murphy S. Davis L. Katz

1990-01-01

233

Stochastic Microgeometry for Displacement Mapping  

Microsoft Academic Search

Creating surfaces with intricate small-scale features (mi- crogeometry) and detail is an important task in geomet- ric modeling and computer graphics. We present a model processing method capable of producing a wide variety of complex surface features based on displacement mapping and stochastic geometry. The latter is a branch of mathe- matics that analyzes and characterizes the statistical prop- erties

Craig A. Schroeder; David E. Breen; Christopher D. Cera; William C. Regli

2005-01-01

234

Job Displacement, Disability, and Divorce  

Microsoft Academic Search

Earnings shocks should affect divorce probability by changing a couple's expected gains from marriage. We find that the divorce hazard rises after a spouse's job displacement but does not change after a spousal disability. This difference casts doubt on a purely pecuniary motivation for divorce following earnings shocks, since both types of shocks exhibit similar long-run economic consequences. Furthermore, the

2004-01-01

235

Knowledge Integration and Displaced Volume  

Microsoft Academic Search

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as

Marcia C. Linn; Bat-Sheva Eylon

2000-01-01

236

RECREATION BENEFITS AND DISPLACED FACILITIES  

EPA Science Inventory

A new recreation site or improvement of an existing site results in an increase in demand for that site perhaps at the expense of substitute facilities. A brief literature review indicates differing views on how benefits from displaced facilities should be treated. The author dem...

237

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

238

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

239

Interfacial effects in oil displacements  

SciTech Connect

The surface stress-deformation behavior of some real phase interfaces, such as crude oil-brine interfaces, is believed to be viscoelastic. In an effort to provide a general framework for understanding such behavior, the author has proposed the simple surface material, for which the present stress is determined by the past history of only the surface deformation gradient. After considering the concept of isotropy, the author is led to isotropic simple surface materials and the simple surface fluid. The linear Boussinesq surface fluid is a limiting case of the simple surface fluid, for which the relaxation time of the surface is so short or the flow so slow that memory effects disappear. Both the measurement of surface viscoelastic behavior and its effect upon the entrapment and displacement of residual oil are discussed. Unstable foams are used for mobility control in the displacement of residual oil by carbon dioxide or nitrogen. A qualitative analysis is developed for the displacement of an unstable foam in a porous media. The effects of the magnitude of the London-van der Waals forces, of the surface tension, of the surface viscosities, of the quality (volume fraction of the gas), of the bubble size, and of the viscosity of the foaming agent solution are investigated. Finally, a statistical structural model is used in the context of local volume averaging to examine the effects of interfacial tension, the interfacial viscosities, and wetting upon the capillary pressure and relative permeability functions in an unsteady-state displacement. Within the immediate the neighborhood of a displacement front, simulations, especially of inhibitions, should employ unsteady-state relative permeabilities.

Ramamohan, T.R.

1985-01-01

240

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

241

An Inexpensive Interferometric Setup for Measuring Microscopic Displacements  

NASA Astrophysics Data System (ADS)

In an interesting article published in an issue of The Physics Teacher, Reichert1 gives some didactic examples about static friction force between a plastic block and a wooden plane on which it rests. To explain the experiments, he uses a simple model based on a microscopic ``elastic band'' that connects the atoms of both surfaces. Reichert remarks that ``the block moves, albeit a microscopic distance,'' and that it would be helpful if the student could see these displacements. In another paragraph he states that ``measuring it (displacement) requires delicate and expensive optical instruments.'' Effectively, a measurement of such small displacements generally requires interferometric devices. At our university, we teach basic physics and we are aware of the difficulties that beginners have grasping the concepts involved in static friction force. At the same time, as our research field is related to optics metrology, we could not ignore Reichert's statement. Could we design an experimental device to measure the microscopic displacement referred to by Reichert, keeping it inexpensive and easy to implement? Incidentally, in the same issue of The Physics Teacher, Sawicki2 gives an excellent example of how, with a few common elements, a simple experiment of interferometric measurement can be put within students' reach. In this paper, we suggest the use of a simple interferometric device, built with very common and inexpensive elements, and describe an experiment on static friction force in which the instrument is applied to measure microscopic displacements.

Alanís, Elvio; Romero, Graciela; Martínez, Carlos; Álvarez, Liliana; Salazar, Germán

2004-04-01

242

Measuring Electric Field Induced Subpicometer Displacement of Step Edge Ions  

NASA Astrophysics Data System (ADS)

We provide unambiguous evidence that the applied electrostatic field displaces step atoms of ionic crystal surfaces by subpicometers in different directions via the measurement of the lateral force interactions by bimodal dynamic force microscopy combined with multiscale theoretical simulations. Such a small imbalance in the electrostatic interaction of the shifted anion-cation ions leads to an extraordinary long-range feature potential variation and is now detectable with the extreme sensitivity of the bimodal detection.

Kawai, Shigeki; Canova, Filippo Federici; Glatzel, Thilo; Hynninen, Teemu; Meyer, Ernst; Foster, Adam S.

2012-10-01

243

Pressure Propagation and Brine Displacement in CO2 Storage Formations: The Role of Sealing Units  

Microsoft Academic Search

If carbon dioxide capture and storage technologies are implemented on a large scale, enormous amounts of CO2 will be injected and sequestered underground, which means that large volumes of native brines will be displaced. Provided that there is hydraulic communication to shallow formations, such brine displacement from deep storage reservoirs may impact the hydrologic conditions in fresh-water aquifers, for example

C. Tsang; J. T. Birkholzer; Q. Zhou

2007-01-01

244

Experimental measurement of local displacement and chemical pair correlations in crystalline solid solutions  

SciTech Connect

Measurement of near-neighbor atomic arrangements in crystalline solid solutions is well established and provides meaningful values for chemical preference of atoms for their near neighbors to beyond the first ten neighboring shells. Static displacements (atomic size) between these atom pairs have mostly been either ignored in the recovery of the local pair preferences or removed by making use of the displacement scattering dependence on momentum transfer. With intense and energy tunable x-ray synchrotron sources, our ability to recover these static displacements between atoms has greatly improved. Data taken with multiple x-ray energies to obtain the contrast necessary to separate like from unlike neighbor pair distances are discussed for the two cases studied to date: A locally ordered Ni{sub 77.5}Fe{sub 22.5} crystal and a locally clustered Fe{sub 53}Cr{sub 47} crystal. Analysis of experimental parameters and data gives the systematic and statistical errors on the recovered parameters. Meaningful atomic displacements from the mean lattice can be measured and recovered. These displacements help us understand material properties and will provide theorists with tests for their calculations.

Sparks, C.L.; Ice, G.E.; Robertson, J.L. [Oak Ridge National Lab., TN (United States); Shaffer, L.B. [Anderson Univ., Anderson, IN (United States)

1993-10-01

245

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

2013-09-30

246

Hot-solvent miscible displacement  

SciTech Connect

This work describes an experimental and theoretical investigation of miscible displacement under nonisothermal conditions. The hot miscible floods were performed in an adiabatic glass bead pack, displacing one hydrocarbon by a more viscous hydrocarbon, the latter being at an elevated temperature. As a result, dispersion of both mass and heat took place, and was determined by temperature and concentration measurements. The system was simulated by coupled convective-diffusion and thermal conduction-convection equations. The results of the numerical as well as an approximate analytical solution were compared with the experimentally observed behavior. The numerical and experimental results point to the factors which should be considered in the choice of a solvent for a thermal-miscible type oil recovery process.

Awang, M.; Farouq Ali, S.M.

1980-01-01

247

Knowledge integration and displaced volume  

NSDL National Science Digital Library

This study contrasted spontaneous and reflective knowledge integration instruction delivered using a computer learning environment to enhance understanding of displaced volume. Both forms of instruction provided animated experiments and required students to predict outcomes, observe results, and explain their ideas. In addition, the reflective instruction diagnosed specific inconsistencies in student reasoning and encouraged students to reflect on these dilemmas as well as to construct general principles. We distinguished the impact of instruction on students who believed scientific phenomena are governed by principles (cohesive beliefs) versus students who believed that science is a collection of unrelated ldquofactsrdquo (dissociated beliefs). Students typically held multiple models of displacement, using different explanations depending on the form of assessment. For example, we found that 17% of these middle school students made accurate predictions about displacement experiments prior to instruction and 25% could construct an accurate general principle. However, only 12% consistently used the same explanation across assessments. After instruction, students were more accurate and more consistent: over 50% accurately predicted experimental outcomes, 79% gave an accurate general principle, and about 40% gave consistent responses. We found no advantages for enhanced animations over straightforward animated experiments. The reflective integration instruction led to more substantial long-term changes in student understanding than did spontaneous integration instruction. Furthermore, on a delayed posttest we found that students with cohesive beliefs not only sustained their understanding of displaced volume, but, when exposed to reflective integration instruction, actually continued to construct more predictive views following instruction. In contrast, students with dissociated beliefs made no long-term progress independent of the form of instruction.

Linn, Marcia; Eylon, Bat-Sheva

2006-12-07

248

Refugees and Internally Displaced People  

Microsoft Academic Search

Millions of refugees and internally displaced people (IDP) reflect the human consequences of armed conflicts and disasters\\u000a around the world. These individuals, families, communities, and societies suffer from conditions of war and violence, all\\u000a of which can be considered human rights violations, including torture, rape, abductions, sexual violation, war wounds, deprivation\\u000a of basic needs, ethnic cleansing, persecution and harassment, loss

Nancy Baron; Soeren Buus Jensen; Joop T. V. M. Jong

249

Atomic and electronic structure of the corundum ([alpha]-alumina) (0001) surface  

SciTech Connect

Using a tight-binding, total-energy model, we predict the atomic and electronic structure of the relaxed (1[times]1) corundum (0001) surface. The surface shows a large, bond-length-conserving relaxation, which is allowed by the topology of the surface. The relaxation is driven by a rehybridization of the surface Al atoms to [ital sp][sup 2], and an accompanying drop in the energy of occupied surface states, during the relaxation. Displacements of surface atoms from bulk positions are as large as 0.7 A, and should be observable using a low-energy electron diffraction intensity analysis. Full relaxed atomic positions are reported, as well as a wavelength-resolved surface band structure, including orbital characters of surface states.

Godin, T.J.; LaFemina, J.P. (Molecular Science Research Center, Pacific Northwest Laboratory, P.O. Box 999, Richland, Washington 99352 (United States))

1994-03-15

250

Design of Nafion actuator with enhanced displacement  

NASA Astrophysics Data System (ADS)

A new actuator system has been developed. This actuator uses Nafion, a solid electrolyte, in combination with Platinum Copper (Pt-Cu) electrodes and mobile ions of Cu2+ to create much larger actuation displacement at smaller levels of applied voltage (1V or less). This actuator provides bending deformation. Large deformation is provided by electrode reaction of copper. Since this reaction is reversible, Cu electrode is not consumed by using polarity change of applied voltage. This actuation mechanism is different from others. Because the induction of the large deflection of Nafion, the large number of the mobile cations is essential. Although it is possible to induce a large deflection by applying a higher electric field as alternative way, this would introduce the electrolysis of water that is not desired unless the device is always submerged in water. To convert bending deformation to liner actuation, we designed a device using a pair of Nafion actuator, which is termed as loop actuator. This loop actuator can be designed into the device with large force by making parallel array. Solid polymer electrolyte-metal composite actuator contains water inside. Therefore coating that prevents water from evaporation is needed for its use in dry condition.

Uchida, Mikio; Xu, Chunye; Le Guilly, Marie; Taya, Minoru

2002-07-01

251

An atomic model of crack tip deformation in aluminum using an embedded atom potential  

Microsoft Academic Search

The atomic configuration at the tip of a mode 1 crack in aluminum is modeled by means of molecular dynamics calculations using an embedded atom potential. This potential intrinsically incorporates many-body contributions. This paper is concerned with the characteristics of the atomic displacement fields in comparison to the linear elastic predictions and dislocation emission phenomena. Three crack\\/crystal orientations are examined

R. G. Hoagland; M. S. Daw; S. M. Foiles; M. I. Baskes

1990-01-01

252

High Throughput Screening of Potential Displacer Molecules.  

National Technical Information Service (NTIS)

A bioproduct may be selectively separated from one or more impurities by means of a displacement chromatography system that includes a solvent, a chromatographic resin and a chemically selective displacer. The method includes: dissolving the bioproduct an...

S. M. Cramer K. Rege J. Dordick N. Tugcu

2005-01-01

253

Histone Displacement during Nucleotide Excision Repair  

PubMed Central

Nucleotide excision repair (NER) is an important DNA repair mechanism required for cellular resistance against UV light and toxic chemicals such as those found in tobacco smoke. In living cells, NER efficiently detects and removes DNA lesions within the large nuclear macromolecular complex called chromatin. The condensed nature of chromatin inhibits many DNA metabolizing activities, including NER. In order to promote efficient repair, detection of a lesion not only has to activate the NER pathway but also chromatin remodeling. In general, such remodeling is thought on the one hand to precede NER, thus allowing repair proteins to efficiently access DNA. On the other hand, after completion of the repair, the chromatin must be returned to its previous undamaged state. Chromatin remodeling can refer to three separate but interconnected processes, histone post-translational modifications, insertion of histone variants and histone displacement (including nucleosome sliding). Here we review current knowledge, and speculate about current unknowns, regarding those chromatin remodeling activities that physically displace histones before, during and after NER.

Dinant, Christoffel; Bartek, Jiri; Bekker-Jensen, Simon

2012-01-01

254

Histone Displacement during Nucleotide Excision Repair.  

PubMed

Nucleotide excision repair (NER) is an important DNA repair mechanism required for cellular resistance against UV light and toxic chemicals such as those found in tobacco smoke. In living cells, NER efficiently detects and removes DNA lesions within the large nuclear macromolecular complex called chromatin. The condensed nature of chromatin inhibits many DNA metabolizing activities, including NER. In order to promote efficient repair, detection of a lesion not only has to activate the NER pathway but also chromatin remodeling. In general, such remodeling is thought on the one hand to precede NER, thus allowing repair proteins to efficiently access DNA. On the other hand, after completion of the repair, the chromatin must be returned to its previous undamaged state. Chromatin remodeling can refer to three separate but interconnected processes, histone post-translational modifications, insertion of histone variants and histone displacement (including nucleosome sliding). Here we review current knowledge, and speculate about current unknowns, regarding those chromatin remodeling activities that physically displace histones before, during and after NER. PMID:23202955

Dinant, Christoffel; Bartek, Jiri; Bekker-Jensen, Simon

2012-10-17

255

Giant atoms cast long shadow  

SciTech Connect

Atoms swollen with energy can serve as supersensitive detectors. They also probe the shadow realm where the quantum world of the atom gives way to the familiar classical world. Created in the laboratory, where they live for a few milliseconds inside vacuum chambers, Rydberg atoms acquire their girth when one or sometimes two of their electrons are excited to very high energy levels, displacing them far from the nuclear core. This article describes the atoms, the history of their identification, and future possibilities. 2 figs.

Amato, I.

1996-07-19

256

Multiple displacement amplification on single cell and possible PGD applications  

Microsoft Academic Search

Multiple displacement amplification (MDA) is a technique used in the amplification of very low amounts of DNA and reported to yield large quantities of high-quality DNA. We used MDA to amplify the whole genome directly from a single cell. The most common techniques used in PGD are PCR and fluorescent in-situ hybridization (FISH). There are many limitations to these techniques

Ali Hellani; Serdar Coskun; Moncef Benkhalifa; Abelghani Tbakhi; Nadia Sakati; Ali Al-Odaib; Pinar Ozand

2004-01-01

257

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

258

Clinical application of multiple displacement amplification in preimplantation genetic diagnosis  

Microsoft Academic Search

Multiple displacement amplification (MDA) is a technique used in the amplification of very small amounts of DNA. MDA is reported to yield large quantities of high-quality DNA. The applicability of MDA to single cells was recently demonstrated as a potential technique for preimplantation genetic diagnosis (PGD). This paper shows the first clinical application of MDA in PGD. Two cycles of

Ali Hellani; Serdar Coskun; Abdelghhani Tbakhi; Saad Al-Hassan

2005-01-01

259

Biologically based analysis of lung cancer incidence in a large Canadian occupational cohort with low-dose ionizing radiation exposure, and comparison with Japanese atomic bomb survivors.  

PubMed

Lung cancer incidence is analyzed in a large Canadian National Dose Registry (CNDR) cohort with individual annual dosimetry for low-dose occupational exposure to gamma and tritium radiation using the two-stage clonal expansion model (TSCE) and extensions of the model with up to 10 initiation steps. Models with clonal expansion turned off provide very poor fits and are rejected. Characteristic and distinct temporal patterns of excess relative risk (ERR) are found for dose response affecting early, middle, or late stages of carcinogenesis, that is, initiation with one or more stages, clonal expansion, or malignant conversion. Both fixed lag and lag distributions are used to model time from first malignant cell to incidence. Background rates are adjusted for gender and birth cohort. Lacking individual smoking data, surrogate annual smoking doses based on U.S. annual per capita cigarette consumption appear to account for much of the birth cohort effect, leaving radiation dose response relatively unchanged. The mean cumulative exposure for males receiving nonzero cumulative doses of gamma and tritium radiation was 18.2 mSv. The males have a significant dose response with 33 out of a total of 322 lung cancer cases attributable to radiation. There were 78 incident lung cancer among females, (with mean cumulative exposure of 3.8 mSv among females with nonzero exposure). The dose response for females appears smaller than for males but does not differ significantly from zero or from the male dose response. Findings for males include significant dose-response relationships for promotion and malignant conversion, but not initiation, and a protraction effect (sometimes called an inverse-dose-rate effect, where risk increases with protraction of a given dose). The dose response predicted by our analysis appears consistent with the risk for lung cancer incidence in the Japanese atomic bomb survivors cohort, provided that proper adjustments are made for duration of exposure and differences in background rate parameters. PMID:16840251

Hazelton, William D; Moolgavkar, Suresh H; Curtis, Stanley B; Zielinski, Jan M; Ashmore, J Patrick; Krewski, Daniel

2006-06-01

260

Ecological Character Displacement in Adaptive Radiation  

Microsoft Academic Search

I give an overview of the observational and experimental evidence for ecological character displacement in adaptive radiation. Sixty-one published cases of character displacement involving closely related species (congeners) make up the observational data set. All cases involve divergence, even though parallel and convergent dis- placement are theoretically possible. Character ratios in sympatry were greatest when displacement was symmetric (mean 1.54)

Dolph Schluter

2000-01-01

261

Atrioventricular plane displacement in female endurance athletes  

Microsoft Academic Search

WISLØFF, U., J. HELGERUD, A. STØYLEN, and Ø. ELLINGSEN. Atrioventricular plane displacement in female endurance athletes. Med. Sci. Sports Exerc., Vol. 33, No. 9, 2001, pp. 1503-1510. Introduction: A novel hypothesis for increased ventricular pumping describes the heart as a displacement pump, in which atrioventricular plane displacement (AVPD) is an important mechanism. The hypothesis predicts that AVPD increases at high

ULRIK WISLØFF; JAN HELGERUD; ASBJØRN STØYLEN; ØYVIND ELLINGSEN

262

Burglary Reduction and the Myth of Displacement  

Microsoft Academic Search

Burglary remains a significant crime problem across Australia. While the Australian Institute of Criminology is keen to encourage burglary reduction initiatives, it often encounters the view that targeted operations simply displace crime to another area. This perception of total crime displacement is common, but has no strong evidential basis. While some studies have measured a modest degree of displacement in

Jerry Ratcliffe

2002-01-01

263

Wavelet denoising of displacement estimates in elastography  

Microsoft Academic Search

Wavelet shrinkage denoising of the displacement estimates to reduce noise artefacts, especially at high overlaps in elastography, is presented in this paper. Correlated errors in the displacement estimates increase dramatically with an increase in the overlap between the data segments. These increased correlated errors (due to the increased correlation or similarity between consecutive displacement estimates) generate the so-called “worm” artefact

Udomchai Techavipoo; Tomy Varghese

2004-01-01

264

Displacement Current and Surface Flashover  

SciTech Connect

High-voltage vacuum insulator failure is generally due to surface flashover rather than insulator bulk breakdown. Vacuum surface flashover is widely believed to be initiated by a secondary electron emission avalanche along the vacuum-insulator interface. This process requires a physical mechanism to cause secondary electrons emitted from the insulator surface to return to that surface. Here, we show that when an insulator is subjected to a fast high-voltage pulse, the magnetic field due to displacement current through the insulator can provide this mechanism. This indicates the importance of the voltage pulse shape, especially the rise time, in the flashover initiation process.

harris, J R; Caporaso, G J; Blackfield, D; Chen, Y J

2007-07-17

265

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

266

Inductive Displacement Sensor for Force Measuring in Humanoid Robotic Application: Testing the Invariance on Angular Displacement  

Microsoft Academic Search

A planar displacement inductive sensor, usable in robotics, is presented in the paper. The sensor is composed of two sensor elements. The first sensor element detects vertical displacement while the second sensor element detects horizontal displacement. Combining information from these two sensor elements, it is possible to determine displacement in a plane. Sensor element is a pair of meander coils.

Snezana M. Djuric; Laszlo Nagy; Mirjana Damnjanovic

2009-01-01

267

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 also practice adding and subtracting electrons from an atom and determining the overall charges on atoms.

Integrated Teaching And Learning Program

268

A large displacement formulation for anisotropic beam analysis  

Microsoft Academic Search

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

Marco Borri; Teodoro Merlini

1986-01-01

269

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

270

A theoretical model to predict both horizontal displacement and vertical displacement for electromagnetic induction-based deep displacement sensors.  

PubMed

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

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

2011-12-28

271

Adsorptive displacement analysis of many-component priority pollutants on activated carbon  

Microsoft Academic Search

Multiple trace contaminants on activated carbon are determined by adsorptive displacement, i.e., equilibration in a solvent containing a large excess of a strongly adsorbing solute (displacer). Many components are desorbed completely. For most of the others, the adsorption isotherms become linear and mutually independent with a zero intercept, and the amount of the remaining adsorbed contaminant is readily calculable. The

Sharad. Thakkar; Milton. Manes

1987-01-01

272

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

273

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

274

Design and modeling for comb drive actuator with enlarged static displacement  

Microsoft Academic Search

New comb drives using high stiffness ratio springs are designed and modeled to provide capabilities of large static displacement and continuous motion for applications, such as micro XY stage, two dimensional lens scanner, variable optical attenuator, and optical switch, etc. The maximum static displacement of conventional comb drive is constrained by the side sticking effect of comb finger electrodes. Since

Chihchung Chen; Chengkuo Lee

2004-01-01

275

Length-displacement scaling relations and the development of faults  

NASA Astrophysics Data System (ADS)

Faults are complex systems whose growth and general evolution are still not well understood. Such an understanding, however, is important for several reasons: one is that seismogenic faults generate earthquakes and another is that faults are major conduits for fluids (groundwater, geothermal water, gas, oil, magma). It is widely accepted that faults normally initiate from 'flaws' or weaknesses in the rocks, but their subsequent development and growth and their seismogenic activity are less well understood. Here we present results on the slip/displacement-length scaling relations, both for faults and co-seismic ruptures, from a single comparatively small area, namely the eastern flank of the volcano Etna, Italy (Sicily). Using these data, together with data from the literature and analytical and numerical models, we provide a general growth model for faults. Following an earthquake in a fault zone, the co-seismic rupture length and the slip are commonly measured. Similarly, in a structural analysis of major faults, the total fault length and displacement are measured when possible. It is well known that typical rupture length - slip ratios are generally orders of magnitude larger than typical fault length-displacement ratios. So far, however, most of the measured co-seismic ruptures and faults have been from different areas and commonly hosted by rocks of widely different mechanical properties (which have strong effects on these ratios). The data presented here is composed of length-displacement ratios from 7 fault zones in Holocene lava flows on the flanks of the volcano Etna and 19 co-seismic rupture lengths-slips mostly from the same fault zones and thus hosted by rocks with largely the same mechanical properties. For the co-seismic ruptures, the average length is 3,657 m, the average slip 0.31 m, and the average length-slip ratio 19,595. For the faults, the average length is 6,341 m, the average displacement 73 m, and the average length-displacement ratio 130. Thus, the average rupture-slip ratio is about 150-times larger than the length-displacement ratio. We propose that the differences between the length-slip and the length-displacement ratios can be partly explained by dynamic Young's modulus of fault zone being 101-2-times greater than its static modulus. In this model, the dynamic modulus controls the length-slip ratios whereas the static modulus controls the length-displacement ratio. We suggest that the common aseismic slip in fault zones is partly due to adjustment of the short-term seismogenic length-slip ratios to the long-term length-displacement ratios. Fault displacement is here regarded as analogous to plastic flow, in which case the long-term displacement can be very large so long as sufficient shear stress concentrates in the fault. In conclusion, this model explains, partly at least, the difference in the slip/displacement-length scaling relations between co-seismic ruptures and faults and also explains slow earthquakes and aseismic slip, features that are now known to be very common in active fault zones.

Gudmundsson, Agust; De Guidi, Giorgio; Scudero, Salvatore

2013-04-01

276

Atom laser based on Raman transitions  

Microsoft Academic Search

In this paper we present an atom laser scheme using a Raman transition for the output coupling of atoms. A beam of thermal atoms (bosons) in a metastable atomic state is pumped into a multimode atomic cavity. This cavity is coupled through spontaneous emission to another cavity for the atomic ground state. Above a certain threshold pumping rate a large

G. M. Moy; J. J. Hope; C. M. Savage

1997-01-01

277

Juvenile Songbirds Compensate for Displacement to Oceanic Islands during Autumn Migration  

PubMed Central

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

Thorup, Kasper; Ortvad, Troels Eske; Rab?l, J?rgen; Holland, Richard A.; T?ttrup, Anders P.; Wikelski, Martin

2011-01-01

278

Design and analysis of displacement measurement system based on the four-quadrant detector  

NASA Astrophysics Data System (ADS)

The four-quadrant detector is mainly used in high-precision displacement measurement and other related fields. With the emergence of displacement problem in a large number of projects, the displacement measurement accuracy, speed and reliability have become increasingly demanding. In this paper, the measurement principle of four-quadrant detector is analyzed theoretically, the displacement measurement system based on four-quadrant detector is designed, and the experimental platform is built to test and validate the stability, measurement accuracy and range of the displacement measurement system. Experimental results show that: the deviation of the same spot position on measurement system is less than 0.17?m. The measurement error of spot displacement is less than 3.7?m.

Gao, Zi-jun; Dong, Li-li; Xu, Wen-hai

2013-09-01

279

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

280

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

281

Displacement Based Seismic Design Criteria  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

Costello, J.F.; Hofmayer, C.; Park, Y.J.

1999-03-29

282

DISPLACEMENT BASED SEISMIC DESIGN CRITERIA  

SciTech Connect

The USNRC has initiated a project to determine if any of the likely revisions to traditional earthquake engineering practice are relevant to seismic design of the specialized structures, systems and components of nuclear power plants and of such significance to suggest that a change in design practice might be warranted. As part of the initial phase of this study, a literature survey was conducted on the recent changes in seismic design codes/standards, on-going activities of code-writing organizations/communities, and published documents on displacement-based design methods. This paper provides a summary of recent changes in building codes and on-going activities for future codes. It also discusses some technical issues for further consideration.

HOFMAYER,C.H.

1999-03-29

283

Establishing the isotropy of displacement cascades in UO2 through molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

Simulation of displacement cascades is a valuable approach in furthering our understanding of how the physical properties of nuclear fuel evolve. Molecular dynamics simulations of displacement cascades in uranium dioxide have been performed at three different primary knock-on atom energies. Various properties of the cascade (such as the spatial extent and total number of defects) are monitored as the cascade progresses. Both the statistical variation of these properties and the dependence on the crystallographic direction of the primary knock-on atom are investigated in order to determine the isotropy of these events.

Bishop, Clare L.; Grimes, Robin W.; Parfitt, David C.

2010-10-01

284

Atomic-orbital close-coupling calculations for collisions involving fusion relevant highly charged impurity ions using very large basis sets  

SciTech Connect

The atomic-orbital close-coupling formalism is a well-known method for the semiclassical treatment of ion-atom collisions. Cross sections for these kinds of collisions are mainly needed in the analysis of certain spectroscopic data from nuclear fusion experiments as well as astrophysical data. We shall outline how the computational implementation can be improved in such a way that collisions involving heavy, highly charged impurity ions, such as Ar{sup 18+} can be treated. Furthermore we show and discuss exemplary results.

Igenbergs, Katharina; Wallerberger, Markus; Schweinzer, Josef; Aumayr, Friedrich [Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstr.8-10/134, A-1040 Vienna (Austria); Max-Planck-Institute of Plasma Physics, Boltzmannstr.2, D-85748 Garching (Germany); Institute of Applied Physics, Vienna University of Technology, Wiedner Hauptstr.8-10/134, A-1040 Vienna (Austria)

2012-05-25

285

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

Code of Federal Regulations, 2011 CFR

...false Engine displacement, motorcycle classes. 86.419-2006 Section 86.419-2006...419-2006 Engine displacement, motorcycle classes. (a)(1) Engine displacement...b) Motorcycles will be divided into classes based on engine displacement....

2011-07-01

286

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

2010-06-30

287

Cholesterol Displaces Palmitoylceramide from Its Tight Packing with Palmitoylsphingomyelin in the Absence of a Liquid-Disordered Phase  

PubMed Central

A set of different biophysical approaches has been used to explore the phase behavior of palmitoylsphingomyelin (pSM)/cholesterol (Chol) model membranes in the presence and absence of palmitoylceramide (pCer). Fluorescence spectroscopy of di-4-ANEPPDHQ-stained pSM/Chol vesicles and atomic force microscopy of supported planar bilayers show gel L?/liquid-ordered (Lo) phase coexistence within the range XChol = 0–0.25 at 22°C. At the latter compositional point and beyond, a single Lo pSM/Chol phase is detected. In ternary pSM/Chol/pCer mixtures, differential scanning calorimetry of multilamellar vesicles and confocal fluorescence microscopy of giant unilamellar vesicles concur in showing immiscibility, but no displacement, between Lo cholesterol-enriched (pSM/Chol) and gel-like ceramide-enriched (pSM/pCer) phases at high pSM/(Chol + pCer) ratios. At higher cholesterol content, pCer is unable to displace cholesterol at any extent, even at XChol < 0.25. It is interesting that an opposite strong cholesterol-mediated pCer displacement from its tight packing with pSM is clearly detected, completely abolishing the pCer ability to generate large microdomains and giving rise instead to a single ternary phase. These observations in model membranes in the absence of the lipids commonly used to form a liquid-disordered phase support the role of cholesterol as the key determinant in controlling its own displacement from Lo domains by ceramide upon sphingomyelinase activity.

Busto, Jon V.; Sot, Jesus; Requejo-Isidro, Jose; Goni, Felix M.; Alonso, Alicia

2010-01-01

288

Assessing the displacement effects of the Internet  

Microsoft Academic Search

This study examines the ''medium-centric'' and ''user-centric'' approaches in investigating the displacement effects of the Internet. Results from a random sample survey support the ''medium-centric'' approach in displacement effect. The use of the Internet does displace traditional media use of television, newspapers, and radio. The Internet performs a sub- stitutive rather than supplementary function. More important, the use of absolute

Paul S. N. Lee; Louis Leung

2008-01-01

289

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

290

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

291

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

292

Rollback Atomicity  

Microsoft Academic Search

We introduce a new non-interference criterion for concurrent programs: rollback atomicity. Similarly to other definitions of atomicity, rollback atomicity of a given concurrent execution requires that there be a matching serial execution. Rollback atomicity differs from other definitions of atomicity in two key regards. First, it is formulated as a special case of view refinement. As such, it requires a

Serdar Tasiran; Tayfun Elmas

2007-01-01

293

SMA-based smart damper/displacement transducer  

NASA Astrophysics Data System (ADS)

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

Mao, Chen-xi; Li, Hui

2005-05-01

294

Improved Wide Range Expressions for Displacements and Inverse Displacements for Standard Fracture Toughness Specimens.  

National Technical Information Service (NTIS)

Wide range expressions (interpolating polynomials) for displacements for standard ASTM fracture testing specimens have been developed. The strategy for fitting was to fit displacements as a function of crack length for all of the specimens using a similar...

J. A. Kapp

1992-01-01

295

TIMING, EXTENT, AND SPATIAL PROGRESSION OF NEOGENE DISPLACEMENT TRANSFER, SOUTHERN WALKER LANE, WESTERN GREAT BASIN  

Microsoft Academic Search

Displacement transfer through structural stepovers linking misaligned segments of large-magnitude intracontinental transcurrent faults involve components of translational and rotational displacement and strain accommodated by complex three-dimensional arrays of structures. Although vertical-axis rotation of large spatial domains is well documented in many structural stepovers, the degree to which rotation is accommodated by rigid block and\\/or by distributed strain is not adequately

J. W. Geissman; J. S. Oldow; D. F. Stockli; J. S. Grow

2009-01-01

296

Land expropriation and displacement in Bangladesh  

Microsoft Academic Search

This paper examines land grabbing in Bangladesh and views such seizures through the lens of displacement and land encroachment. Two different but potentially interacting displacement processes are examined. The first, the char riverine and coastal sediment regions that are in a constant state of formation and erosion, are contested sites ripe for power plays that uproot small producers on their

Shelley Feldman; Charles Geisler

2012-01-01

297

Planar inductive sensor for small displacement  

Microsoft Academic Search

This paper presents a meander type displacement inductive sensor, developed in printed circuit board (PCB) technology. It also describes design, realization and the input inductance measurement of sensor. The displacement in two directions (less than 0.5 mm) can be detected by using two sensor's elements (i.e. two pairs of meander coils). In each pair, one of the coils is fixed,

S. Duric; L. Nad; B. Biberdzic; M. Damnjanovic; L. Zivanov

2008-01-01

298

Displacement and Knowledge Construction in Literature Reviews.  

ERIC Educational Resources Information Center

Two literature reviews are interpreted to demonstrate how they are informed by what the author labels the "displacement story," that is, a story of how one prevailing professional paradigm is replaced by another. This study demonstrates how the narration, structure, and language in each review render particular tellings of the displacement story.…

Steinley, Gary

299

Proceedings of the Displaced Homemakers Conference.  

ERIC Educational Resources Information Center

The 1979 Displaced Homemakers Conference focused on developing awareness of services available from various Illinois agencies to displaced homemakers, generating the spirit and means for cooperative relationships among agencies serving them, and offering prototypes of how women's centers are attempting to coordinate the various services of state…

Illinois State Office of Education, Springfield. Div. of Adult Vocational and Technical Education.

300

Displacement damage analogs to ionizing radiation effects  

Microsoft Academic Search

We show that concepts, such as effective equivalent dose and the quality factor, which have long been found useful in comparing the effects of different kinds of ionizing radiation, are also applicable in correlating displacement damage effects in semiconductors. In the case of displacement damage, the energy deposition process is determined by the nonionizing energy loss (NIEL), instead of linear

Geoffrey P Summers; Edward A Burke; Michael A Xapsos

1995-01-01

301

Do Dogs (Canis familiaris) Understand Invisible Displacement?  

Microsoft Academic Search

Domestic dogs (Canis familiaris) perform above chance on invisible displacement tasks despite showing few other signs of possessing the necessary representational abilities. Four experiments investigated how dogs find an object that has been hidden in 1 of 3 opaque boxes. Dogs passed the task under a variety of control conditions, but only if the device used to displace the object

Emma Collier-Baker; Joanne M. Davis; Thomas Suddendorf

2004-01-01

302

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

PubMed

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

Russo, Christopher J; Golovchenko, J A

2012-04-06

303

Local Time Displacement of Substorm Expansion in Conjugate Hemispheres  

NASA Astrophysics Data System (ADS)

Because the Earth's magnetic field is largely dipolar and symmetric, many auroral features are conjugate between the northern and southern hemispheres. However, previous work has shown that the aurora can be nonconjugate. Most previous optical conjugacy studies have been limited to ground based observations or ground based and space based imager comparisons. In both cases at least one observation point is restricted to viewing only small scale features. Conjugate observations of the large scale behavior of the aurora have been confined to rare, serendipitous space based imager conjunctions and single spacecraft viewing of both hemispheres which is tempered by large oblique viewing angles. As the Polar spacecraft's apogee has descended in the the southern hemisphere, the Polar Ultraviolet Imager (UVI) has spent an increasing amount of time viewing the southern aurora. Simultaneously, the Wideband Imaging Camera (WIC) onboard the IMAGE spacecraft has been observing the northern aurora. By using image data from both spacecraft, we are able to systematically analyze the degree of auroral conjugacy on synoptic scales and over a wide variety of geomagnetic conditions. In this work, we focus on the conjugacy of the region of intense auroral emission during substorm onset and expansion. We find a persistent displacement in local time of the region of active aurora during substorm expansion; features in the northern hemisphere are shifted westward (duskward) relative to the conjugate point of the southern hemisphere aurora by up to a few thousand kilometers. Often there is a shift in the opposite direction observed before and at substorm onset. The same sense of displacement has been reported in earlier work. The sense or magnitude of the displacement showns no obvious correlation with the interplanetary magnetic field orientation or strength as suggested in previous studies. Therefore, we suggest that the displacement in local time of the region of intense auroral emission is a result of the asymmetric distortion of the magnetic field by the large scale field-aligned currents associated with substorms.

Fillingim, M. O.; Tung, Y.; Parks, G. K.; Mende, S. B.; Frey, H. U.; Immel, T. J.

2003-12-01

304

Miscible displacement by high-pressure gas at Block 31  

Microsoft Academic Search

The world's first large-scale miscible displacement project by high-pressure gas injection has produced 130,000,000 bbl, almost double the original estimated primary recovery of 69,000,000 bbl, at the University Block 31 field in Crane County, Texas. The field-wide project began in 1952, and will keep the unit on stream well into the future, with ultimate recovery efficiency estimated at 60%. Infill

J. H. Hardy; N. Robertson

1975-01-01

305

Resolution Quality and Atom Positions in Sub-Angstrom Electron Microscopy  

SciTech Connect

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

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

2005-02-15

306

The role of finite displacements in vocal fold modeling.  

PubMed

Human vocal folds experience flow-induced vibrations during phonation. In previous computational models, the vocal fold dynamics has been treated with linear elasticity theory in which both the strain and the displacement of the tissue are assumed to be infinitesimal (referred to as model I). The effect of the nonlinear strain, or geometric nonlinearity, caused by finite displacements is yet not clear. In this work, a two-dimensional model is used to study the effect of geometric nonlinearity (referred to as model II) on the vocal fold and the airflow. The result shows that even though the deformation is under 1?mm, i.e., less than 10% of the size of the vocal fold, the geometric nonlinear effect is still significant. Specifically, model I underpredicts the gap width, the flow rate, and the impact stress on the medial surfaces as compared to model II. The study further shows that the differences are caused by the contact mechanics and, more importantly, the fluid-structure interaction that magnifies the error from the small-displacement assumption. The results suggest that using the large-displacement formulation in a computational model would be more appropriate for accurate simulations of the vocal fold dynamics. PMID:24008392

Chang, Siyuan; Tian, Fang-Bao; Luo, Haoxiang; Doyle, James F; Rousseau, Bernard

2013-11-01

307

Displacive radiation-induced structural contraction in nanocrystalline ZrN  

SciTech Connect

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

2012-07-23

308

Molecular-dynamics simulation of displacement cascades in Cu: analysis of replacement sequences  

SciTech Connect

Molecular-dynamics computer simulations of displacement cascades in copper have been performed for recoil energies up to 450 eV. Statistical analyses of the atomic replacements are presented. Linear replacement sequence lengths are extremely short on the average. The effect of the cooling phase of the cascade is discussed.

King, W.E.; Benedek, R.

1981-01-01

309

Electron displacement damage in copper and aluminium in a high voltage electron microscope  

Microsoft Academic Search

Defect clusters are observed to form in copper and aluminium during examination at ?20°C in a high voltage electron microscope when the voltage is greater than ?500 kv and the beam current is high (0·1–0·4 ?amps in a 5 ? spot). Experimental and theoretical considerations show that the damage is the result of the direct displacement of lattice atoms by

M. J. Makin

1968-01-01

310

Crustal displacements due to continental water loading  

NASA Astrophysics Data System (ADS)

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

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

311

Rotor Displacement of the Ultrasonic Motor Having an Angular Displacement Self-Correction Function  

NASA Astrophysics Data System (ADS)

This paper deals with the experimental investigation for confirmation of rotor displacement of the ultrasonic stepping motor having an angular displacement self-correction function. The experiment focused on the relationship between the rotor’s vibration displacement and its staying position for the self-correction. The result proved that the rotor always stays at the position where the displacement is smallest by cutting a slit into the rotor. Moreover, it has also been found that the stable self-correction of rotor angular displacement depends upon both the rotor driving frequency and rotor clamping force.

Chen, Xiaoduo; Kusakabe, Chiharu; Tomikawa, Yoshiro; Takano, Takehiro

1993-09-01

312

Atomic Orbitals  

NSDL National Science Digital Library

The Atomic Orbitals website is a distribution point for the orbital image generating program "Orbital Viewer" as well as the home of a collection of images generated with the program. Atomic and molecular orbitals are constructed. For atoms, the hydrogenic solution, up to n=30, is generated and for molecules the linear combination of atomic orbitals method is used.

Manthey, David

2009-03-24

313

Atomic Structure  

NSDL National Science Digital Library

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

Consortium, The C.

2011-12-11

314

Viscoplastic fluid displacements in horizontal narrow eccentric annuli: stratification and travelling wave solutions  

NASA Astrophysics Data System (ADS)

We consider laminar displacement flows in narrow eccentric annuli, oriented horizontally, between two fluids of Herschel-Bulkley type, (i.e. including Newtonian, power-law and Bingham models). This situation is modelled via a Hele-Shaw approach. Whereas slumping and stratification would be expected in the absence of any imposed flow rate, for a displacement flow we show that there are often steady-state travelling wave solutions in this displacement. These may exist even at large eccentricities and for large density differences between the fluids. When heavy fluids displace light fluids, annular eccentricity opposes buoyancy and steady states are more prevalent than when light fluids displace heavy fluids. For large ratios of buoyancy forces to viscous forces we derive a lubrication-style displacement model. This simplification allows us to find necessary and sufficient conditions under which a displacement can be steady, which can be expressed conveniently in terms of a consistency ratio. It is interesting that buoyancy does not appear in the critical conditions for a horizontal well. Instead a competition between fluid rheologies and eccentricity is the determining factor. Buoyancy acts only to determine the axial length of the steady-state profile.

Carrasco-Teja, M.; Frigaard, I. A.; Seymour, B. R.; Storey, S.

315

Spatial displacement correlations in polymeric systems  

NASA Astrophysics Data System (ADS)

The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities.

Puosi, F.; Leporini, D.

2012-04-01

316

Spatial displacement correlations in polymeric systems.  

PubMed

The spatial correlations of the monomer displacements are studied via molecular-dynamics simulations of a melt of fully flexible, unentangled polymer chains with different length, interacting potential, density, and temperature. Both the scalar and the vector characters of the correlations are considered and their extension quantified in terms of suitable dynamical correlation lengths. Displacements performed at both short, i.e., vibrational, and long times, i.e., comparable to the structural relaxation time, are investigated. On both time scales the spatial correlations are modulated according to the radial distribution function g(r) to an extent which is determined by the character of the correlations, the time scale of the displacements and the structural slowing down. The spatial correlations of the short-time displacements have clear directional character. The modulus correlations of the long-time displacements are more marked, especially for sluggish states. Analogous findings are found by experiments on colloids. By inspecting the dynamical heterogeneities of states with slowed-down dynamics, it is observed that fast monomers exhibit correlations which are stronger and more differing from the bulk than the slow ones. It is shown that states with identical average vibrational monomer displacement exhibit identical spatial correlations of the monomer displacements pertaining to the subsets of the fast and the slow monomers characterizing both the short-time and the long-time dynamical heterogeneities. PMID:22559500

Puosi, F; Leporini, D

2012-04-28

317

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

318

Hydrogen atoms in proteins: Positions and dynamics  

PubMed Central

Hydrogen atoms constitute about half of the atoms in proteins. Thus they contribute to the complex energy landscape of proteins [Frauenfelder, H., Sligar, S. G. & Wolynes, P. G. (1991) Science 254, 1598-1603]. Neutron crystal structure analysis was used to study the positions and mean-square displacements of hydrogen in myoglobin. A test of the reliability of calculated hydrogen atom coordinates by a comparison with our experimental results has been carried out. The result shows that >70% of the coordinates for hydrogen atoms that have a degree of freedom is predicted worse than 0.2 Å. It is shown that the mean-square displacements of the hydrogen atoms obtained from the Debye-Waller factor can be divided into three classes. A comparison with the dynamic mean-square displacements calculated from the elastic intensities obtained from incoherent neutron scattering [Doster, W., Cusack, S. & Petry, W. (1989) Nature 337, 754-756] shows that mainly the side-chain hydrogen atoms contribute to dynamic displacements on a time scale faster than 100 ps.

Engler, Niklas; Ostermann, Andreas; Niimura, Nobuo; Parak, Fritz G.

2003-01-01

319

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

320

Large scale averaging of drainage at local capillary control.  

National Technical Information Service (NTIS)

Large scale averaging is important for the description of displacement processes in heterogeneous porous media for example, in petroleum reservoirs. For immiscible displacement, key objective is the determination of effective (pseudo) capillary pressure a...

Y. C. Yortsos C. Satik

1991-01-01

321

Design and experimental research on miniature fiber-optic displacement sensor  

NASA Astrophysics Data System (ADS)

A detecting method based on Fizeau interferometer for fiber-optic displacement sensing is presented to detect highprecision displacement in nanometer scale. On the basis of optical interferometry and common-path Fizeau interferometer, micro displacement can be detected by accurately measuring the distance changes between the surfaces of fiber-optic collimator and measuring mirror. Its characteristics are as follows: with common-path interferometer, dependence of energy transmitting fiber to ambient temperature is eliminated, then the effect of ambient temperature variation to the system is reduced; with the method of phase generated carrier modulation/demodulation instead of electric-control phase modulator, the optical path is formed with all-fiber components to improve the application flexibility in the system; by micro fiber-optic collimator with diameter of 1mm, the overall dimension of the displacement sensor is greatly reduced, which makes the use of the sensor more flexible. In the paper, the structure and parameters of miniature all-fiber common-path fiber-optic displacement sensor is studied, the experimental platform for high-precision displacement calibration is established, and a series of performance tests are completed. Experimental results show: with the working distance of 0-14mm, the measuring resolution of the miniature fiber-optic displacement sensor can reach 20nm, and the measuring dynamic range can get 116.9dB, which indicate that the miniature fiber-optic displacement sensor has superior performances with high resolution, high precision and large dynamic range.

Gao, Fei; Yang, Jun

2012-11-01

322

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

323

Loading effects on time-variable gravity and surface displacements  

NASA Astrophysics Data System (ADS)

The global circulation of surface geophysical fluids (e.g. atmosphere, ocean hydrology) induce mass redistribution at the Earth's surface, and therefore gravity variations and surface deformation, over a large frequency domain. With the help of Love numbers, or the Green's function formalism, an output from general circulation models (GCM), they can be modeled with a high precision on an operational basis. We present here the computations of time-variable gravity and surface displacements, due to atmospheric, non-tidal oceanic and continental hydrological loading, and show the improvement in terms of reduction of the noise signal in GRACE KBRR residuals, Jason and Topex/Poseidon crossovers, as well as surface displacement observations (GPS, SLR or VLBI).

Boy, J.; Gegout, P.; Hinderer, J.; Luthcke, S. B.; Pavlis, E. C.; Lemoine, F. G.; Rowlands, D. D.

2008-12-01

324

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

325

Dynamics and Structure of Energetic Displacement Cascades.  

National Technical Information Service (NTIS)

This paper summarizes recent progress in the understanding of energetic displacement cascades and the primary state of damage in metals. On the theoretical side, the availability of supercomputers has greatly enhanced our ability to simulate cascades by m...

R. S. Averback T. Diaz de la Rubia R. Benedek

1987-01-01

326

Development of a 3kW free-piston Stirling engine with the displacer gas-spring partially sprung to the power piston  

Microsoft Academic Search

The development of a 3-kW helium free-piston Stirling engine with a novel displacer drive is discussed. In this displacer drive, the displacer is sprung to the power piston as well as to ground. The analysis and tests indicate that a large portion of the engine power is transmitted from the displacer to the piston through the gas spring coupling between

G. Chen; J. McEntee

1991-01-01

327

Inverted liver with suprahepatic, anteriorly displaced gallbladder.  

PubMed

A suprahepatic, anteriorly displaced gallbladder in association with an inverted liver is an extremely rare congenital anomaly. We report the clinical and radiologic findings associated with a 78-year-old woman presenting with shortness of breath, desaturation, hypercapnia and hypoxemia. An abnormal chest radiograph demonstrated right hemi-diaphragmatic elevation consistent with a possible eventration. Subsequent imaging by computed tomography (CT) demonstrated an inverted liver with an anteriorly displaced, suprahepatic gallbladder. PMID:20666167

Hibbs, Harold; Ahmad, Usman

328

Polymer displacement in dye-affinity chromatography  

Microsoft Academic Search

Displacement of lactate dehydrogenase from dye-affinity matrices with poly(ethyleneimine) (PEI) was shown to be an effective elution strategy. It resulted in better recoveries and sharper elution profiles than traditional non-specific elution while the purification factors were unchanged. The elution is assumed to proceed via displacement of bound protein by PEI when the polymer binds to the dye-ligands. Complete elution of

Igor Yu. Galaev; Pär Arvidsson; Bo Mattiasson

1995-01-01

329

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

330

Development and evolution of character displacement.  

PubMed

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. PMID:22257002

Pfennig, David W; Pfennig, Karin S

2012-01-18

331

Study on optical fiber based displacement sensor  

NASA Astrophysics Data System (ADS)

Fiber optic sensor is commonly used in control and monitoring system for material deformation, strain, temperature, pressure and other industrial process parameters. Fiber optic displacement sensor based on intensity modulation can be designed by using the transmission technique where the intensity gradually changes due to change of detected laser intensity. Previous optical fiber based displacement sensors are constructed using two fibers along with a mirror arrangement or a single optical fiber acting as both transmitter and receiver such as 2X1 fiber couplers. The reported resolution of the system was in the range of 5 ?m-10 ?m. In our present study the displacement sensor composed of a laser source, optical fiber cable, microscope objective and power meter is designed. As in source-fiber coupling geometry, the microscope objective focuses the laser light onto a multimode glass fiber. The other end of the fiber is coupled to a power meter. As the fiber is displaced towards the focused spot, the detected power changes. The displacement resolution of 5 ?m is obtained with this simple setup. In the present paper, the results of theoretical analysis and experimental study of such a simple optical fiber based displacement sensor are presented.

Chakraborty, B.; Sinha, B. K.

2011-10-01

332

Displacement sensor for indoor machine calibrations.  

PubMed

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

Mudassar, Asloob Ahmad; Butt, Saira

2013-05-20

333

Biologically Based Analysis of Lung Cancer Incidence in a Large Canadian Occupational Cohort with Low-Dose Ionizing Radiation Exposure, and Comparison with Japanese Atomic Bomb Survivors  

Microsoft Academic Search

Lung cancer incidence is analyzed in a large Canadian National Dose Registry (CNDR) cohort with individual annual dosimetry for low-dose occupational exposure to gamma and tritium radiation using the two-stage clonal expansion model (TSCE) and extensions of the model with up to 10 initiation steps. Models with clonal expansion turned off provide very poor fits and are rejected. Characteristic and

William D. Hazelton; Suresh H. Moolgavkar; Stanley B. Curtis; Jan M. Zielinski; J. Patrick Ashmore; Daniel Krewski

2006-01-01

334

Determination of the displacement energy of O, Si and Zr under electron beam irradiation  

SciTech Connect

The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to {approx}1.5 x 10{sup 22} e m{sup -2} has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be {approx}400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

Edmondson, Philip D [ORNL; Weber, William J [ORNL; Namavar, Fereydoon [University of Nebraska Medical Center; Zhang, Yanwen [ORNL

2012-01-01

335

Determination of the displacement energies of O, Si and Zr under electron beam irradiation  

NASA Astrophysics Data System (ADS)

The response of nanocrystalline, stabilizer-free cubic zirconia thin films on a Si substrate to electron beam irradiation with energies of 4, 110 and 200 keV and fluences up to ˜1.5 × 1022 e m-2 has been studied to determine the displacement energies. The 110 and 200 keV irradiations were performed in situ using a transmission electron microscope; the 4 keV irradiations were performed ex situ using an electron gun. In all three irradiations, no structural modification of the zirconia was observed, despite the high fluxes and fluences. However the Si substrate on which the zirconia film was deposited was amorphized under the 200 keV electron irradiation. Examination of the electron-solid interactions reveals that the kinetic energy transfer from the 200 keV electrons to the silicon lattice is sufficient to cause atomic displacements, resulting in amorphization. The kinetic energy transfer from the 200 keV electrons to the oxygen sub-lattice of the zirconia may be sufficient to induce defect production, however, no evidence of defect production was observed. The displacement cross-section value of Zr was found to be ˜400 times greater than that of O indicating that the O atoms are effectively screened from the electrons by the Zr atoms, and, therefore, the displacement of O is inefficient.

Edmondson, P. D.; Weber, W. J.; Namavar, F.; Zhang, Y.

2012-03-01

336

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

SciTech Connect

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

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

2010-08-03

337

Time Scaling of the Rates of Produced Fluids in Laboratory Displacements  

SciTech Connect

In this report, the use of an asymptotic method, based on the time scaling of the ratio of produced fluids, to infer the relative permeability exponent of the displaced phase near its residual saturation, for immiscible displacements in laboratory cores was proposed. Sufficiently large injection rates, the existence of a power law can be detected, and its exponent inferred, by plotting in an appropriate plot the ratio of the flow rates of the two fluids at the effluent for some time after breakthrough.

Laroche, Catherine; Chen, Min; Yortsos, Yanis C.; Kamath, Jairam

2001-02-27

338

Vacancies and interstitial atoms in e--irradiated germanium  

NASA Astrophysics Data System (ADS)

High purity Ge wafers have been irradiated at low temperatures with MeV electrons and have subsequently been investigated by x-ray diffraction methods. The intensity of the Huang diffuse scattering shows that a high concentration of defects (>1019 cm-3) can be frozen in at 4 K. A large fraction of the defects is stabilized in the form of close Frenkel pairs which are characterized by the nearly perfect cancellation of the long range displacement fields of the interstitial atom and the vacancy. We discuss the absolute size of these displacements as well as the introduction rate of the defects, which is of the order of ?=3 cm-1. The high defect introduction rates are at variance to the results of electrical and optical investigations and indicate that these methods detect only a few percent of the total defect concentration which is produced and frozen in at 4 K. The consequences for the understanding of the defect production in Ge and for the assumption of an athermal migration of interstitial atoms are discussed in close relation to similar results for Si. In addition, we discuss the differences between the defect patterns observed after 4 K irradiation to those observed after room-temperature irradiations and the thermally activated defect reactions up to the final annealing at 600 K.

Ehrhart, P.; Zillgen, H.

1999-04-01

339

Atomic Interactions  

NSDL National Science Digital Library

Explore the interactions between various combinations of two atoms. Turn on the force arrows to see either the total force acting on the atoms or the individual attractive and repulsive forces. Try the "Adjustable Attraction" atom to see how changing the parameters affects the interaction.

Simulations, Phet I.; Adams, Wendy; Blanco, John; Perkins, Kathy; Podolefsky, Noah; Wieman, Carl

2009-08-01

340

Corporate Restructuring, Downsizing, and the Middle Class: The Process and Meaning of Worker Displacement in the “New” Economy  

Microsoft Academic Search

This article conceptualizes, describes, and analyzes the phenomenon of corporate downsizing and the experience of worker displacement as a process of work and employment change that occurs within the context of structural changes in the economy, large firms and labor markets. The research is based on a case study of displaced IBM computer and Link aerospace workers in Binghamton, New

Charles Koeber

2002-01-01

341

Inverse models for fault displacement history with application to the San Jacinto and San Andreas fault zones, southern California, USA  

Microsoft Academic Search

A large number of observations, which represent a diversity of time intervals (5 Ma to present), constrain the average displacement rates along the young (1.5 Ma) San Jacinto and old (5 Ma) southernmost San Andreas fault zones in southern California. To understand the implications of these average displacement rates, we formulated an inverse problem, by which we estimate instantaneous fault

R. A. Bennett; A. M. Friedrich; K. P. Furlong

2003-01-01

342

Optical fiber rotary displacement sensor.  

PubMed

Shafts are needed in the operation and control of a broad range of manufacturing systems. Angular position of a shaft is one of the most common parameters measured in industrial and manufacturing systems. In this work, we report a class of a simple, multimode fiber intensity sensors developed to serve as a viable alternative to conventional rotary sensors. The basic structure of the twist sensor is a multimode fiber with a large core and/or a high numerical aperture (N.A.) sandwiched between two fibers with a small core and/or a low N.A. The sensor works by exciting selected modes in the multimode section of fiber. As the multimode section is twisted, mode coupling occurs, resulting in a redistribution of power in the multimode fiber. Power remaining in the selected modes is received by a pickup fiber. Fibers are joined with the aid of small capillary tubes. The usable range is about 135 degrees to 160 degrees depending on the length of twisted section. No evidence of hysteresis has been found. Based on the noise level of the detector used in the experiment and the slope of the measured sensor response, a sensitivity of 0.029' is estimated for the prototype twist sensors. PMID:20555848

West, S T; Chen, C L

1989-10-01

343

Inefficiency of upward displacement operating theatre ventilation.  

PubMed

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

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

1996-08-01

344

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

345

Cell and tissue deformation measurements: Texture correlation with third-order approximation of displacement gradients.  

PubMed

Cells remarkably are capable of large deformations during motility and when subjected to mechanical force. Measurement of mechanical deformation (i.e. displacements, strain) is critical to understand functional changes in cells and biological tissues following disease, and to elucidate basic relationships between applied force and cellular biosynthesis. Microscopy-based imaging modalities provide the ability to noninvasively visualize small cell or tissue structures and track their motion over time, often using two-dimensional (2D) digital image (texture) correlation algorithms. For the measurement of complex and nonlinear motion in cells and tissues, implementation of texture correlation algorithms with high order approximations of displacement mapping terms are needed to minimize error. Here, we extend a texture correlation algorithm with up to third-order approximation of displacement mapping terms for the measurement of cell and tissue deformation. We additionally investigate relationships between measurement error and image texture, defined by subset entropy. Displacement measurement error is significantly reduced when the order of displacement mapping terms in the texture correlation algorithm matches or exceeds the order of the deformation observed. Displacement measurement error is also inversely proportional to subset entropy, with well-defined cell and tissue structures leading to high entropy and low error. For cell and tissue studies where complex or nonlinear displacements are expected, texture correlation algorithms with high order terms are required to best characterize the observed deformation. PMID:23992835

Lim, Kai Y; Henderson, Jonathan T; Neu, Corey P

2013-08-07

346

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

347

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

348

Displacement Addition on Linking Extensional Fault Arrays in the Canyonlands Graben, Utah  

NASA Astrophysics Data System (ADS)

Studies of brittle fault populations over the past decade have revealed that large extensional faults grow by the lengthening, interaction and physical linkage of en echelon fault segments. However, the temporal evolution of displacement accumulation during segment interaction and linkage is difficult to unravel due to a lack of direct observation during each stage in the fault array development. The process of profile re-adjustment prevents reconstruction of the growth history of a fault from its final configuration, and as a result, several models for the growth trajectory of a fault array undergoing linkage are possible. Observational data with which to constrain the relative timing and mode of displacement accumulation during the linkage process are currently lacking. We use the deformation of late Pleistocene-Holocene stream systems by the growth of a active normal faults in The Grabens, Canyonlands National Park, Utah to constrain the mode of growth of fault arrays. Coupling fault displacement data with geomorphic analysis of deformed present-day and palaeo-streams, permits sequential reconstruction of both simple 2-segment fault arrays and complex multi-segment populations from their initial component segments to the present day displacement geometry. In particular, these data provide information on the relative rates of displacement addition. For example, the presence of waterfalls where streams cross fault scarps indicates abrupt rates of displacement accumulation which we can relate to the hard linkage process. The reconstruction of both three- and six-segment faults reveal common aspects of displacement distribution through time: (1) Displacement accumulation occurs almost entirely in the interaction and linkage phase. (2) Interaction between segments causes enhanced displacement addition in overlap zones. (3) Despite interaction in the soft-linkage stage, faults do not achieve a characteristic profile during this phase (4) Displacement accrues rapidly immediately following linkage, and recovery to a standard D-l profile is gained through this process. (5) The locus of displacement accumulation is not fixed in time; the central fault segment does not always experience the greatest displacement enhancement. Preliminary results of cosmogenic 10Be exposure dating of bedrock with quartz from the Permian Cedar Mesa Sandstone indicate recent (<10ka) timing of rapid displacement addition on linking faults.

Commins, D. C.; Gupta, S.; Cartwright, J. A.; Phillips, W. M.

2003-12-01

349

Plane displacement measurement of rigid body by laser speckle  

NASA Astrophysics Data System (ADS)

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than +/-14?m and +/-6.25% respectively, under the displacement range of 300?m.

Zhong, Chuan; Shen, Changyu; Lin, Zhaoxiang; Li, Ke

2010-12-01

350

Plane displacement measurement of rigid body by laser speckle  

Microsoft Academic Search

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than +\\/-14mum and +\\/-6.25% respectively, under the displacement range of 300mum.

Chuan Zhong; Changyu Shen; Zhaoxiang Lin; Ke Li

2010-01-01

351

Plane displacement measurement of rigid body by laser speckle  

Microsoft Academic Search

A measurement system of plane displacement in rigid body was designed. Plane displacement was calculated by the cross-correlation of speckle image. Measurement results showed that the absolute-error and the opposite-error of the plane displacement less than ±14 ?m and ±6.25% respectively, under the displacement range of 300 ?m.

Chuan Zhong; Changyu Shen; Linzhao Xiang; Ke Li

2010-01-01

352

Spatial distribution measurement of atomic radiation with an astigmatism-corrected Czerny-Turner-type spectrometer in the Large Helical Device  

SciTech Connect

Emission lines in the visible/UV wavelength ranges are observed with 80 lines of sight which cover an entire poloidal cross section of the plasma in the Large Helical Device. The emitted light is received with optical fibers having 100 {mu}m diameter and is guided into a 1.33 m Czerny-Turner-type spectrometer based on spherical mirrors for collimating and focusing. A charge-coupled device having 13.3x13.3 mm{sup 2} area size is used as the detector and the spectra from all the lines of sight are recorded perpendicularly to the wavelength dispersion. The spectrometer is equipped with optics located in front of the entrance slit to correct the difference between the meridional and sagittal focal points, and thus the astigmatism, which otherwise causes severe cross talk between adjacent optical fiber images on the detector, is corrected. Consequently, simultaneous spectral measurement with 80 lines of sight is realized. The Zeeman splitting of a neutral helium line, {lambda}667.8 nm (2 {sup 1}P-3 {sup 1}D), which is caused by the magnetic field for plasma confinement, is measured with the spectrometer. Though the obtained line profile is in general a superposition of several components on the same line of sight, they can be separated according to their different splitting widths. The two-dimensional poloidal distribution of the helium line intensity is obtained with the help of a tomographic technique.

Goto, Motoshi; Morita, Shigeru [National Institute for Fusion Science, Toki 509-5292 (Japan)

2006-10-15

353

Atomic replacement and vacancy formation and annihilation on iridium surfaces  

NASA Astrophysics Data System (ADS)

Field ion microscopy is used here to observe surface atomic processes when the chemical nature of an adatom differs from that of the surface atoms. On the iridium 001-plane surface, an adsorbed rhenium atom will displace an iridium atom from the substrate to form an Re-Ir-vacancy bound complex at about 230 K. On heating the sample to about 300 K, this complex dissociates and the rhenium atom becomes incorporated into the surface. This represents a kind of atomic-scale surface alloying. Alternatively, the Re-Ir cluster can be removed by field evaporation to leave a lattice vacancy, into which another adatom can subsequently diffuse.

Tsong, Tien T.; Chen, Chong-Lin

1992-01-01

354

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

355

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

PubMed

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. PMID:23742550

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

356

FPGA-Based Smart Sensor for Online Displacement Measurements Using a Heterodyne Interferometer  

PubMed Central

The measurement of small displacements on the nanometric scale demands metrological systems of high accuracy and precision. In this context, interferometer-based displacement measurements have become the main tools used for traceable dimensional metrology. The different industrial applications in which small displacement measurements are employed requires the use of online measurements, high speed processes, open architecture control systems, as well as good adaptability to specific process conditions. The main contribution of this work is the development of a smart sensor for large displacement measurement based on phase measurement which achieves high accuracy and resolution, designed to be used with a commercial heterodyne interferometer. The system is based on a low-cost Field Programmable Gate Array (FPGA) allowing the integration of several functions in a single portable device. This system is optimal for high speed applications where online measurement is needed and the reconfigurability feature allows the addition of different modules for error compensation, as might be required by a specific application.

Vera-Salas, Luis Alberto; Moreno-Tapia, Sandra Veronica; Garcia-Perez, Arturo; de Jesus Romero-Troncoso, Rene; Osornio-Rios, Roque Alfredo; Serroukh, Ibrahim; Cabal-Yepez, Eduardo

2011-01-01

357

Hybrid atom-membrane optomechanics  

NASA Astrophysics Data System (ADS)

We report on the realization of a hybrid optomechanical system in which ultracold atoms are coupled to a micromechanical membrane. The atoms are trapped in the intensity maxima of an optical standing wave formed by retroreflection of a laser beam from the membrane surface. Vibrations of the membrane displace the standing wave, thus coupling to the center-of-mass motion of the atomic ensemble. Conversely, atoms imprint their motion onto the laser light, thereby modulating the radiation pressure force on the membrane. In this way, the laser light mediates a long-distance coherent coupling between the two systems. When the trap frequency of the atoms is matched to the membrane frequency, we observe resonant energy transfer. Moreover, we demonstrate sympathetic damping of the membrane motion by coupling it to laser-cooled atoms. Theoretical investigations show that the coupling strength can be considerably enhanced by placing the membrane inside an optical cavity. This could lead to quantum coherent coupling and ground-state cooling of the membrane via a distant atomic ensemble.

Korppi, Maria; Jöckel, Andreas; Rakher, Matthew T.; Camerer, Stephan; Hunger, David; Hänsch, Theodor W.; Treutlein, Philipp

2013-08-01

358

Television and Schooling: Displacement and Distraction Hypotheses.  

ERIC Educational Resources Information Center

|Research on two hypotheses regarding television's possible negative effect on children's academic achievement is reviewed. A lack of support is found for the displacement hypothesis (time spent with television is taken away from more academically beneficial activities) and limited support for the distraction hypothesis (exposure to television…

Roberts, Donald F.; And Others

1993-01-01

359

A linear displacement power factor compensator  

Microsoft Academic Search

Nowadays, the consumer of energy has the concern in operating with a value of power factor inside of a value stipulated by the energy concessionaries. It is know that the power factor is related with the displacement power factor and the total harmonic distortion. The present work has as main objective the development and implementation of a linear compensator of

J. V. R. Nunes; R. A. M. Braga; F. B. Libano; S. L. Muller

2004-01-01

360

Character displacement and the origins of diversity.  

PubMed

In The Origin of Species, Darwin proposed his principle of divergence of character (a process now termed "character displacement") to explain how new species arise and why they differ from each other phenotypically. Darwin maintained that the origin of species and the evolution of differences between them is ultimately caused by divergent selection acting to minimize competitive interactions between initially similar individuals, populations, and species. Here, we examine the empirical support for the various claims that constitute Darwin's principle, specifically that (1) competition promotes divergent trait evolution, (2) the strength of competitively mediated divergent selection increases with increasing phenotypic similarity between competitors, (3) divergence can occur within species, and (4) competitively mediated divergence can trigger speciation. We also explore aspects that Darwin failed to consider. In particular, we describe how (1) divergence can arise from selection acting to lessen reproductive interactions, (2) divergence is fueled by the intersection of character displacement and sexual selection, and (3) phenotypic plasticity may play a key role in promoting character displacement. Generally, character displacement is well supported empirically, and it remains a vital explanation for how new species arise and diversify. PMID:21043778

Pfennig, David W; Pfennig, Karin S

2010-12-01

361

Ecological Character Displacement in Quantitative Genetic Models  

Microsoft Academic Search

We study, both analytically and numerically, models of ecological character displacement for two species that compete for the same set of food sources. These models include quantitative genetics and Lotka–Volterra type competition and are symmetric with respect to the two species. We allow for various shapes of the carrying capacity and the competition function, and we discuss under what general

Barbara Drossel; Alan McKane

1999-01-01

362

Retraining Displaced Workers--Barriers and Facilitators.  

ERIC Educational Resources Information Center

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

Wolansky, William D.

363

40 CFR 205.153 - Engine displacement.  

Code of Federal Regulations, 2013 CFR

...Materials (ASTM) E 29-67. (b) For rotary engines, displacement means the maximum...combustion chamber between two rotor tip seals minus the minimum volume of that combustion chamber between those two rotor seals times three times the number of...

2013-07-01

364

Simulation of random cell displacements in QCA  

Microsoft Academic Search

In this work, we analyze the behaviour of quantum-dot cellular automata (QCA) building blocks in the presence of random cell displacements. The QCA cells are modeled using the coherence vector description and simulations are performed using the QCADesigner tool. We evaluate various fundamental circuit elements, including the wire, the inverter, the majority gate, and the two approaches to wire crossing:

Gabriel Schulhof; Konrad Walus; Graham A. Jullien

2007-01-01

365

Acoustic shear wave displacement measurement using ultrasound  

Microsoft Academic Search

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

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

1996-01-01

366

Indian Displacement from the Loess Hills  

Microsoft Academic Search

Indian nations have been thoroughly removed from the Loess Hills of the Missouri River valley. That removal, however, does not conform to the typical story of Indian displacement from the forested East or the Great Plains; it was specific to a time and a place and reflected the changing status of Indian sovereignty in the United States. While it was

Dave McDermott

2009-01-01

367

Revisiting Schramm's Radiotown: Media Displacement and Saturation  

Microsoft Academic Search

In 1959 Wilbur Schramm collected data on the media use behavior of children in what he believed was the last remaining town in North America to have radio as its only electronic mass media, and he concluded the primary impact of new media was the displacement of incumbent media. This research returns to Schramm's “Radiotown” for two follow-up studies to

Jay Newell

2007-01-01

368

Fiber-optic couplers as displacement sensors  

NASA Astrophysics Data System (ADS)

We introduce the novel concept of using a fiber-optic coupler as a versatile displacement sensor. Comparatively long fiber-optic couplers, with a coupling region of approximately 10 mm, are manufactured using standard communication SM fiber and placed in a looped-back configuration. The result is a displacement sensor, which is robust and highly sensitive over a wide dynamic range. This displacement sensor resolves 1 - 2 µm over distances of 1 1.5 mm and is characterized by the essential absence of a 'spring constant' plaguing other strain gauge-type sensors. Consequently, it is possible to couple to extremely weak vibrations, such as the skin displacement affected by arterial heart beat pulsations. Used as a wrist-worn heartbeat monitor, the fidelity of the arterial pulse signal has been shown to be so high that it is possible to not only determine heartbeat and breathing rates, but to implement a new single-point blood pressure measurement scheme which does not squeeze the arm. In an application as a floor vibration sensor for the non-intrusive monitoring of independently living elderly, the sensor has been shown to resolve the distinct vibration spectra of different persons and different events.

Baruch, Martin C.; Gerdt, David W.; Adkins, Charles M.

2003-04-01

369

Job Displacement and the Rural Worker.  

ERIC Educational Resources Information Center

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

Podgursky, Michael

370

SOFTWARE ENABLED VARIABLE DISPLACEMENT PUMPS - EXPERIMENTAL STUDIES  

Microsoft Academic Search

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

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

2006-01-01

371

An inexpensive vertical-displacement indentation tester  

Microsoft Academic Search

A displacement transducer is used to follow the vertical movements of an indenter tip, which is forced into the material specimen under a selected dead weight load. Measurement of indentation depth under load and vertical recovery following load removal allows both plastic and elastic characteristics of the material to be evaluated. The equipment gives consistent results, is readily portable, and

P. J. P. White; M. E. Aulton

1980-01-01

372

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

373

Displacement-Type He II Heat Switch  

Microsoft Academic Search

The operation of a heat switch is described in which the conducting substance is liquid He II and in which the nonconducting state is achieved by displacing the He II with a poor conductor, e.g., Teflon. The switch is well suited for use in the first stage of a magnetic refrigerator operating with a bath temperature near 1°K. At this

Ferdinand J. Shore

1960-01-01

374

The politics of displacement in multiparty Kenya  

Microsoft Academic Search

Since the transition to multipartyism in the 1990s, internal displacement in Kenya has been part of political strategies to retain or win power. Cycles of aggression and antagonist articulation of ethnic identity of perceived hostile voters have enmeshed grievances over unequal land distribution into political discourses of exclusion. Increased use of hate speech, intimidation and inability to recover from the

Prisca Mbura Kamungi

2009-01-01

375

Investigation into Displacement of Placer Gold Particles  

Microsoft Academic Search

The experimental research in displacement of gold particles in washed-out thickness of sand-gravel layer is conducted. The parameters of ability of gold particles to migrate in pulp flow are determined, and their immersion into loose soil is investigated.

V. E. Filippov; N. G. Eremeeva; E. S. Sleptsova

2003-01-01

376

Stability analysis of miscible displacement processes  

SciTech Connect

This paper presents a linear perturbation analysis of viscosity- and gravity-induced instability in miscible displacement processes. The analysis takes into account the time-dependent behavior of the basic flow solution. It also considers the velocity dependence in the hydrodynamic dispersion expressions. By solving analytically the perturbation equations, the necessary and sufficient conditions for instability in miscible displacement processes are derived. These criteria are related to the well-known Dumore's velocity and to a critical wavelength for finger growth. Furthermore, they are calculated at the most unstable location in the solvent-oil mixing zone. The equations derived then relate quantitatively major process variables to the onset of instability in a miscible displacement process. Examples are presented to illustrate the applications of the criteria derived. It is shown that as the displacement process proceeds, the injection rate can be gradually increased. Furthermore, for dipping and stratified reservoirs, and for laboratory core experiments, a threshold time can be reached, after which the process is said to be in a state of unconditional stability.

Lee, S.T.; Culham, W.E.; Gary, K.M.

1984-04-01

377

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.

378

A wavelength encoded rotary displacement sensor  

Microsoft Academic Search

A novel concept for a digital rotary displacement sensor is presented. Broadband light issuing from the encoder input fibre is focused on a 9 bit Gray coded dis. Rays emerging from the disc under Littrow conditions are diffracted back to the input fibre by a grating. The output spectrum is encoded as a function of the disc's angular position. The

M. Maghoo; J. Marcou

1993-01-01

379

A wavelength encoded rotary displacement fibre sensor  

Microsoft Academic Search

An improved design for a fibre optic rotary encoder is described in which a Gray code disc is used to encode angular displacement information on a broadband spectrum. Broadband light from a halogen lamp is brought to the encoder by an input fibre positioned in the focal plane of an aspheric lens. A diffraction grating disperses the collimated beam of

M. Maghoo

1994-01-01

380

NDCX-II accelerator, random displacements  

ScienceCinema

The Neutralized Drift Compression Experiment-II (NDCX-II) accelerator is designed to deposit a pulse of ions almost all at once on a foil target in order to create warm dense matter. This visualization shows the progress of an ion beam through NDCX-II if the accelerating coils are randomly displaced by two millimeters.

381

DENSE: Displacement Encoding with Stimulated Echoes in Cardiac Functional MRI  

Microsoft Academic Search

Displacement encoding with stimulated echoes (DENSE) was developed for high-resolution myocardial displacement mapping. Pixel phase is modulated by myocardial displacement and data spatial resolution is limited only by pixel size. 2D displacement vector maps were generated for the systolic action in canines with 0.94 × 1.9 mm nominal in-plane resolution and 2.3 mm\\/? displacement encoding. A radial strain of 0.208

Anthony H. Aletras; Shujun Ding; Robert S. Balaban; Han Wen

1999-01-01

382

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

383

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

384

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

385

Atom Builder  

NSDL National Science Digital Library

This is a virtual manipulative that students may use to construct various atoms up to carbon by creating protons and neutrons from up and down quarks and adding electrons. Students are challenged to keep the electrical charge of the atom neutral and to ensure the imbalance between protons and neutrons doesn't become great enough to result in radioactive decay!

Online, Nova

2011-02-08

386

Democritean Atomism  

Microsoft Academic Search

An atomic structure of matter was proposed by Leucippus and Democritus in Ancient Greece in the fifth century bc as a response to an argument of Parmenides to the effect that change is impossible. For the ancient atomists permanent reality\\u000a consists of portions of being (atoms) each characterised by an unchanging shape and size. Change involves the motion and rearrangement

Alan Chalmers

387

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

388

Study of electromigration in eutectic SnPb solder stripes using the edge displacement method  

Microsoft Academic Search

Electromigration (EM) parameters in the eutectic SnPb solder were measured using the edge displacement method (EDM) and an\\u000a atomic force microscope (AFM) in the temperature range of 60° to 140°C. The measured drift velocity was found to be 0.3 Å\\/sec\\u000a when the solder stripe was stressed under 4.9×104 A\\/cm2 at 80°C, and it increased as the current density or the

C. K. Chou; Y. C. Hsu; Chih Chen

2006-01-01

389

Study of electromigration in eutectic SnPb solder stripes using the edge displacement method  

Microsoft Academic Search

Electromigration (EM) parameters in the eutectic SnPb solder were measured using the edge displacement method (EDM) and an atomic force microscope (AFM) in the temperature range of 60° to 140°C. The measured drift velocity was found to be 0.3 Å\\/sec when the solder stripe was stressed under 4.9×104 A\\/cm2 at 80°C, and it increased as the current density or the

C. K. Chou; Y. C. Hsu; Chih Chen

2006-01-01

390

InAs\\/AlGaSb Piezoresistive Cantilever for Sub-Angstrom Scale Displacement Detection  

Microsoft Academic Search

We report on the fabrication and characterization of 0.3-mum-thick piezoresistive cantilevers based on the InAs\\/AlGaSb heterostructure. The dependence of the displacement resolution on the cantilever size, which ranges from 20×10 to 2×1 {\\\\micron}2, has been studied by a novel characterization method using an atomic force microscope. The results show that downscaling the cantilevers improves their performances, and an optimum resolution

Lionel F. Houlet; Hiroshi Yamaguchi; Sen Miyashita; Yoshiro Hirayama

2004-01-01

391

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

392

Efimov physics in atom-dimer scattering of Li atoms  

Microsoft Academic Search

Li atoms in the three lowest hyperfine states display universal properties when the S-wave scattering length between each pair of states is large. Recent experiments reported four pronounced features arising from Efimov physics in the atom-dimer relaxation rate, namely two resonances and two local minima. We use the universal effective-field theory to calculate the atom-dimer relaxation rate at zero temperature.

H.-W. Hammer; Daekyoung Kang; Lucas Platter

2010-01-01

393

Large-scale percolation theory of drainage  

Microsoft Academic Search

Large-scale averaging is important for the description of displacement processes in heterogeneous porous media. For immiscible displacement, a key objective is the determination of effective (pseudo) capillary pressure and phase permeabilities. Present continuum models rely on volume averaging, mixture theories, and homogenization methods, typically under the premise of capillary control. However, such methods are intrinsically unable to provide the local

Y. C. Yortsos; C. Satik; J.-C. Bacri; D. Salin

1993-01-01

394

Adjustment to trauma exposure in refugee, displaced, and non-displaced Bosnian women.  

PubMed

The war in Bosnia resulted in the displacement of millions of civilians, most of them women. Ten years after the civil war, many of them are still living as refugees in their country of origin or abroad. Research on different refugee groups has continuously reported persistent levels of posttraumatic stress disorder (PTSD) and other mental-health problems in this population. The present study compared PTSD and self-concept in Bosnian refugee women (n = 29) with women who were internally displaced (IDP; n = 26) and non-displaced women (n = 32). Data were collected using the Bosnian Trauma Questionnaire and four scales assessing self-esteem, perceived incompetence, externality of control attribution, and persistence. IDPs scored significantly higher on PTSD symptoms, externality of control attribution and perceived incompetence, and lower on self-esteem than both refugee and non-displaced women. The level of education most strongly predicted PTSD symptom severity, followed by the type of displacement, and exposure to violence during the war. Associations of self-concept with displacement and psychopathology were inconsistent, with type of displacement predicting control attributions but not other aspects of self-concept and PTSD symptoms being partly related to perceived incompetence and self-esteem. These results support previous findings stating that, in the long run, refugees show better mental health than IDPs, and that witnessing violence is a traumatic experience strongly linked to the development of PTSD symptoms. Results further indicate that education plays an important role in the development of PTSD symptoms. Associations of control attributions and type of displacement were found; these results have not been previously documented in literature. PMID:18802740

Schmidt, Martina; Kravic, Nera; Ehlert, Ulrike

2008-09-02

395

Atomic-scale and microscale friction studies of graphite and diamond using friction force microscopy  

NASA Astrophysics Data System (ADS)

Friction between graphite and diamond surfaces against a sharp silicon nitirde tip was measured using a friction force microscope (FFM). Atomic-scale friction images of a freshly cleaved highly oriented pyrolytic graphite exhibited the same periodicity as that of the graphite surface; however, the peaks in friction profiles and those in corresponding topography profiles were displaced relative to each other. Using the Fourier expansion of the interaction potential, the conservative interatomic forces between the FFM tip and the graphite surface have been calculated. It is shown that the variations in atomic-scale friction and the observed displacement between the peaks in the frictional (or lateral) force and those in the corresponding topography can be explained by the variations in interatomic forces in the normal and lateral directions. Thus, the observed variation in friction force may not necessarily occur as a result of the commonly believed atomic-scale stick-slip process, but can be due to variation in the intrinsic lateral force between the sample and the FFM tip. At large scan sizes (50 x 50 sq nm or larger), the variation of friction for graphite and a single-crystal (IIa) diamond was found to correlate with the variations in the local slope of the sample surface, suggesting that a ratchet mechanism is responsible for variations in microscale friction.

Ruan, Ju-Ai; Bhushan, Bhushan

1994-11-01

396

Atom-by-atom spectroscopy at graphene edge  

Microsoft Academic Search

The properties of many nanoscale devices are sensitive to local atomic configurations, and so elemental identification and electronic state analysis at the scale of individual atoms is becoming increasingly important. For example, graphene is regarded as a promising candidate for future devices, and the electronic properties of nanodevices constructed from this material are in large part governed by the edge

Kazu Suenaga; Masanori Koshino

2010-01-01

397

Differential effects of tetracaine on delayed potassium channels and displacement currents in frog skeletal muscle.  

PubMed Central

1. Delayed K+-currents and displacement currents were studied with a voltage-clamp technique. 2. In normal fibres, the conductance of the delayed channel grows e-fold per 3 millivolts at sufficiently negative potentials and reaches a limiting value of 2-10 m-mho/cm2 (mean 5-8 m-mho/cm2) at positive potentials. Adding tetracaine (2 mM) reduces the limiting conductance, shifts the voltage-dependence of the delayed channel to +25 mV more positive potentials and slows the kinetics fourfold. 3. By contrast, the displacement currents are virtually unaltered by 2 mM tetracaine. Their voltage-dependence is shifted by less than 5 mV and their kinetics are unaffected. 4. Tetraethylammonium ions (TEA) are known to slow the kinetics of delayed K+-channels fivefold but fail, like tetracaine, to change the kinetics of the displacement currents. 5. Both tetracaine and TEA have thus large effects on the 'gating' of the delayed channel, yet little or none on the displacement currents. This suggests that the displacement currents in skeletal muscle are for the most part unrelated to the opening and closing of delayed channels. It is estimated that 'gating' the delayed channel in muscle may require no more than 1 or 2% of the observed charge displacement.

Almers, W

1976-01-01

398

High displacement sensitivity in asymmetric plasmonic nanostructures.  

PubMed

The strong couplings between two asymmetric plasmonic nanostructures can lead to ultra-sensitive optical responses when their separation changes. We employ electromagnetic numerical simulations to study the displacement sensitivity of two kinds of plasmonic systems: (1) a split-ring resonator and a metal rod; (2) two metal rods of asymmetric lengths. Structural asymmetry makes antiparallel current interactions possible and greatly enhances the sensitivity to 5%/nm for normalized frequency changes and 29%/nm for normalized transmittance changes. These are the highest displacement sensitivity among all physical systems investigated so far. In addition, we also find that these systems display a universal scaling curve independent of their shapes or dimensions. These asymmetric plasmonic nanostructures will open widespread applications from strain mapping, surface wave or heat wave imaging, optomechanical sensing, to environmental detections. PMID:20721229

Tseng, Hsuan-Chi; Chang, Chih-Wei

2010-08-16

399

Displacement Calibration Techniques for the LIGO Detectors  

NASA Astrophysics Data System (ADS)

Calibration of the gravitational wave data channels of the Laser Interferometer Gravitational Wave Observatory (LIGO) is critical to determining the sensitivity of the detectors to spacetime perturbations produced by distant astronomical bodies. These detectors are designed to measure relative displacement fluctuations at the level of 10-19 m/?Hz at 100 Hz. This calibration requires mirror displacement actuation that can be performed without disrupting the servo lock. For LIGO, the actuation for the length sensing and control servo uses voice-coils surrounding magnets glued to the suspended mirrors. This actuation has been calibrated using three techniques: simple Michelson, frequency modulation, and radiation pressure. These methods, which span a wide range of actuation strengths, will be described and compared.

Goetz, Evan

2008-04-01

400

Emergency contraception among refugees and the displaced.  

PubMed

In 1994, the international relief community began to recognize and address the reproductive health needs of refugees and displaced populations. A minimum initial service package of reproductive health services for refugees and the displaced, which includes emergency contraception (EC), was developed and recommended for use in refugee settings. This paper describes the experience of one international relief organization, the International Rescue Committee (IRC), in introducing EC into its worldwide reproductive health program. A recent IRC survey found that EC is available in 4 out of 14 settings where it provides reproductive health services. A case study from Tanzania demonstrates the modes of delivery, the demand for EC by women who have experienced sexual violence, and the community responses to this method of contraception. More information, education, and communication directed at refugee communities; more donor support for supplies; and institutional commitment to train staff are needed to expand refugee access to EC. PMID:9859638

Goodyear, L; McGinn, T

1998-01-01

401

A fiber-optic reflective displacement micrometer  

Microsoft Academic Search

A simple fiber-optic reflection displacement micrometer with a sensitivity of 200 mV ?m?1 and a resolution as low as 0.01 ?m is reported with a theoretical explanation of the experimental results. The sensor consists of a pulsed LED light source and a pair (A and B) of identical receiving fibers and photodetectors that detects the light reflected from the surface

Wen H. Ko; Kow-Ming Chang; Gwo-Jen Hwang

1995-01-01

402

International Monetary Fund and aid displacement.  

PubMed

Several recent papers find evidence that global health aid is being diverted to reserves, education, military, or other sectors, and is displacing government spending. This is suggested to occur because ministers of finance have competing, possibly corrupt, priorities and deprive the health sector of resources. Studies have found that development assistance for health routed to governments has a negative impact on health spending and that similar assistance routed to private nongovernmental organizations has a positive impact. An alternative hypothesis is that World Bank and IMF macro-economic policies, which specifically advise governments to divert aid to reserves to cope with aid volatility and keep government spending low, could be causing the displacement of health aid. This article evaluates whether aid displacement was greater when countries undertook a new borrowing program from the IMF between 1996 and 2006. As found in existing studies, for each $1 of development assistance for health, about $0.37 is added to the health system. However, evaluating IMF-borrowing versus non-IMF-borrowing countries reveals that non-borrowers add about $0.45 whereas borrowers add less than $0.01 to the health system. On average, health system spending grew at about half the speed when countries were exposed to the IMF than when they were not. It is important to take account of the political economy of global health finance when interpreting data on financial flows. PMID:21319721

Stuckler, David; Basu, Sanjay; McKee, Martin

2011-01-01

403

Contactless sub-millimeter displacement measurements  

NASA Astrophysics Data System (ADS)

Weather effects on foldable domes, as used at the DOT and GREGOR, are investigated, in particular the correlation between the wind field and the stresses caused to both metal framework and tent clothing. Camera systems measure contactless the displacement of several dome points. The stresses follow from the measured deformation pattern. The cameras placed near the dome floor do not disturb telescope operations. In the set-ups of DOT and GREGOR, these cameras are up to 8 meters away from the measured points and must be able to detect displacements of less than 0.1 mm. The cameras have a FireWire (IEEE1394) interface to eliminate the need for frame grabbers. Each camera captures 15 images of 640 × 480 pixels per second. All data is processed on-site in real-time. In order to get the best estimate for the displacement within the constraints of available processing power, all image processing is done in Fourier-space, with all convolution operations being pre-computed once. A sub-pixel estimate of the peak of the correlation function is made. This enables to process the images of four cameras using only one commodity PC with a dual-core processor, and achieve an effective sensitivity of up to 0.01 mm. The deformation measurements are well correlated to the simultaneous wind measurements. The results are of high interest to upscaling the dome design (ELTs and solar telescopes).

Sliepen, Guus; Jägers, Aswin P. L.; Bettonvil, Felix C. M.; Hammerschlag, Robert H.

2008-07-01

404

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

405

Atom Lasers.  

National Technical Information Service (NTIS)

The general goal of this research was the generation, manipulation and characterization of coherent and non-classical matter waves, including atom lasers. The research involved both a theoretical and an experimental component. Major achievements from the ...

P. Meystre P. Jessen

2000-01-01

406

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 Suenaga; Alexandre Gloter; Koki Urita; Sumio Iijima

2004-01-01

407

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

408

Uncovering deformation processes from surface displacements  

NASA Astrophysics Data System (ADS)

The aim of this talk is to provide an overview about the most recent outcomes in Earth Sciences, describe the role of satellite remote sensing, together with GPS, ground measurement and further data, for geophysical parameter retrieval in well known case studies where the combined approach dealing with the use of two or more techniques/datasets have demonstrated their effectiveness. The Earth Sciences have today a wide availability of instruments and sensors able to provide scientists with an unprecedented capability to study the physical processes driving earthquakes, volcanic eruptions, landslides, and other dynamic Earth systems. Indeed measurements from satellites allow systematic observation of the Earth surface covering large areas, over a long time period and characterized by growing sample intervals. Interferometric Synthetic Aperture Radar (InSAR) technique has demonstrated its effectiveness to investigate processes responsible for crustal faulting stemming from the detection of surface deformation patterns. Indeed using satellite data along ascending and descending orbits, as well as different incident angles, it is possible in principle to retrieve the full 3D character of the ground motion. To such aim the use of GPS stations providing 3D displacement components is a reliable complementary instrument. Finally, offset tracking techniques and Multiple Aperture Interferometry (MAI) may provide a contribution to the analysis of horizontal and NS deformation vectors. The estimation of geophysical parameters using InSAR has been widely discussed in seismology and volcanology, and also applied to deformation associated with groundwater and other subsurface fluids. These applications often involve the solution of an inverse problem, which means the retrieval of optimal source parameters at depth for volcanoes and earthquakes, from the knowledge of surface deformation from InSAR. In recent years, InSAR measurements combined with traditional seismological and geophysical data, such as teleseismic waveforms, strong motion records and GPS, have also been used by geophysicists for improved rupture models. Many models use equations for a uniform elastic half space stemming from the Okada formulation, but improved data constraints and the use of increasingly sophisticated modeling and inverse methods allowed for the exploration of models with variation of elastic properties in layers or more complex representation of fault and lithosphere structure and rheology. In volcanic studies the role of GPS and InSAR lies in the measurement of pre-eruptive inflation, co-eruptive deflation and the post-eruptive response. The spatio-temporal evolution of volcanic processes, the "breathing" of a volcano, can be monitored with temporal series of InSAR interferograms using multitemporal InSAR techniques. The measured deformation can be used as constraints for the formulation of the inverse problem, to retrieve information concerning the depth, size, shape of the magma chamber (and pressure change) and magma supply dynamics. Deformation modeling commonly relies on simple point sources, dikes and sills; or more complex volume-change sources to produce the different surface deformation patterns caused by magma intrusion.

Stramondo, Salvatore

2013-04-01

409

Atomic entanglement and decoherence  

NASA Astrophysics Data System (ADS)

The generation of entanglement in atomic systems plays a central topic in the fields of quantum information storage and processing. Moreover, a special category of entangled states of multi-atom ensembles, spin squeezed states, have been proven to lead to considerable improvement in the sensitivity of precision measurements compared to systems involving uncorrelated atoms. A treatment of entanglement in open systems is, however, incomplete without a precise description of the process of decoherence which necessarily accompanies it. The theory of entanglement and decoherence are the two main topics of this thesis. Methods are described for the generation of strong correlations in large atomic ensembles using either cavity quantum electrodynamics or measurement outcome conditioned quantum dynamics. Moreover, the description of loss of entanglement resulting from the coupling to a noise reservoir (electromagnetic vacuum) is explored. A spin squeezing parameter is used throughout this thesis as both a measure of entanglement strength and as an indication of the sensitivity improvement above the so-called standard quantum limit (sensitivity obtained with uncorrelated particles) in metrology. The first scheme considered consists of a single mode cavity field interacting with a collection of atoms for which spin squeezing is produced in both resonant and off-resonant regimes. In the resonant case, transfer of squeezing from a field state to the atoms is analyzed, while in the off-resonant regime squeezing is produced via an effective nonlinear interaction (one-axis twisting Hamiltonian). A second, more experimentally realistic case, is one involving the interaction of free space atoms with laser pulses; a projective measurement of a source field originating from atomic fluctuations provides a means of preparing atomic collective states such as spin squeezed and Schrodinger cat states. A new "unravelling" is proposed, that employs the detection of photon number in a single output channel and is capable of producing mesoscopic Schrodinger cat states in a single step. As a first step to understanding the role of cooperative decoherence, of importance in the case of dense pencil-shaped atomic ensembles, the collective spin decoherence of a two multilevel atom system is derived. This calculation is also relevant to entanglement loss for two qubits manipulated using with reading/writing pulses. Finally, a scheme is proposed in which arbitrarily strong entanglement can be produced in a four-wave mixing setup, where the preparation of the atoms in a dark state limits the decoherence to negligible values.

Genes, Claudiu

410

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

411

Digital atomic force microscope moiré method.  

PubMed

In this study, a novel digital atomic force microscope (AFM) moiré method is established to measure the displacement and strain fields. The moiré pattern is generated by the interference between the specimen grating and the virtual reference grating formed by digital image processes. The overlapped image is filtered by the 2-D wavelet transformation to obtain clear interference moiré patterns. From moiré patterns, the displacement and strain fields can be analyzed. The experimental results show that the digital AFM moiré method is very sensitive and easy to realize in nanoscale measurements. PMID:15450663

Liu, Chia-Ming; Chen, Lien-Wen

2004-11-01

412

Development and validation of ultrasound speckle tracking to quantify tendon displacement.  

PubMed

Ultrasound can be used to study tendon movement. However, measurement of tendon movement is mostly based on manual tracking of anatomical landmarks such as the musculo-tendinous junction, limiting the applicability to a small number of muscle-tendon units. The aim of this study was to quantify tendon displacement without anatomical landmarks using a speckle tracking algorithm optimized for tendons in long B-mode image sequences. A dedicated two-dimensional multi-kernel block-matching scheme with subpixel motion estimation was devised to handle large displacements over long sequences. The accuracy of the tracking on porcine tendons was evaluated during different displacements and velocities. Subsequently, the accuracy of tracking the flexor digitorum superficialis (FDS) of a human cadaver hand was evaluated. Finally, the in-vivo accuracy of the tendon tracking was determined by measuring the movement of the FDS at the wrist level. For the porcine experiment and the human cadaver arm experiment tracking errors were, on average, 0.08 and 0.05mm, respectively (1.3% and 1.0%). For the in-vivo experiment the tracking error was, on average, 0.3mm (1.6%). This study demonstrated that our dedicated speckle tracking can quantify tendon displacement at different physiological velocities without anatomical landmarks with high accuracy. The technique allows tracking over large displacements and in a wider range of tendons than by using anatomical landmarks. PMID:20152983

Korstanje, Jan-Wiebe H; Selles, Ruud W; Stam, Henk J; Hovius, Steven E R; Bosch, Johan G

2010-02-11

413

Theoretical studies of atomic transitions  

SciTech Connect

This paper discusses: lifetime of excited states; core-polarization studies; large relativistic calculations; Monte Carlo Hartree-Fock (MCHF) atomic structure package; and MCHF codes for the hypercube. (LSP)

Fischer, C.F.

1990-10-01

414

46 CFR 153.966 - Discharge by liquid displacement.  

Code of Federal Regulations, 2011 CFR

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

2011-10-01

415

46 CFR 153.966 - Discharge by liquid displacement.  

Code of Federal Regulations, 2012 CFR

... 2012-10-01 false Discharge by liquid displacement. 153.966 Section 153...DANGEROUS CARGOES SHIPS CARRYING BULK LIQUID, LIQUEFIED GAS, OR COMPRESSED GAS HAZARDOUS...Procedures § 153.966 Discharge by liquid displacement. The person in...

2012-10-01

416

Alcohol disorder amongst forcibly displaced persons in northern Uganda  

Microsoft Academic Search

BackgroundAlcohol use may be a coping mechanism for the stressors related to forced displacement. The aim of this study was to investigate levels and determinants of alcohol disorder amongst internally displaced persons (IDPs) in northern Uganda.

Bayard Roberts; Kaducu Felix Ocaka; John Browne; Thomas Oyok; Egbert Sondorp

2011-01-01

417

How to predict very large and complex crystal structures  

NASA Astrophysics Data System (ADS)

Evolutionary crystal structure prediction proved to be a powerful approach in discovering new materials. Certain limitations are encountered for systems with a large number of degrees of freedom (“large systems”) and complex energy landscapes (“complex systems”). We explore the nature of these limitations and address them with a number of newly developed tools. For large systems a major problem is the lack of diversity: any randomly produced population consists predominantly of high-energy disordered structures, offering virtually no routes toward the ordered ground state. We offer two solutions: first, modified variation operators that favor atoms with higher local order (a function we introduce here), and, second, construction of the first generation non-randomly, using pseudo-subcells with, in general, fractional atomic occupancies. This enhances order and diversity and improves energies of the structures. We introduce an additional variation operator, coordinate mutation, which applies preferentially to low-order (“badly placed”) atoms. Biasing other variation operators by local order is also found to produce improved results. One promising version of coordinate mutation, explored here, displaces atoms along the eigenvector of the lowest-frequency vibrational mode. For complex energy landscapes, the key problem is the possible existence of several energy funnels - in this situation it is possible to get trapped in one funnel (not necessarily containing the ground state). To address this problem, we develop an algorithm incorporating the ideas of abstract “distance” between structures. These new ingredients improve the performance of the evolutionary algorithm USPEX, in terms of efficiency and reliability, for large and complex systems.

Lyakhov, Andriy O.; Oganov, Artem R.; Valle, Mario

2010-09-01

418

Miscible flooding with displacing fluid containing additive compositions  

SciTech Connect

A method for displacing hydrocarbons from a hydrocarbon-bearing subterranean reservoir by injecting a displacing fluid comprising a primary fluid such as carbon dioxide or rich gas, and an additive such as nitrogen, methane, flue gas, propane, butane, LPG, hydrogen sulfide, carbon monoxide, and mixtures thereof, said additive having a concentration sufficient to adjust the phase equilibrium of mixtures of the displacing fluid with reservoir hydrocarbons. The additive adjusts the phase equilibrium so that utilization of the displacing fluid is more efficient.

Fussell, D. D.; Yellig, W. F.

1985-12-10

419

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

420

Pop Internationalism: Has A Half Century of World Music Trade Displaced Local Culture?  

Microsoft Academic Search

Advances in communication technologies over the past half century have made the cultural goods of one country more readily available to consumers in another, raising concerns that cultural products from large economies – in particular the US – will displace the indigenous cultural products of smaller economies. In this paper we provide stylized facts about the global music consumption and

Fernando Ferreira; Joel Waldfogel

2010-01-01

421

The use of multiple displacement amplification to amplify complex DNA libraries  

Microsoft Academic Search

Complex libraries for genomic DNA and cDNA sequencing analyses are typically amplified using bacterial propagation. To reduce biases, large numbers of colonies are plated and scraped from solid-surface agar. This process is time consuming, tedious and limits scaling up. At the same time, multiple displacement amplification (MDA) has been recently developed as a method for in vitro ampli- fication of

Melissa J. Fullwood; Jack J. S. Tan; Patrick W. P. Ng; Kuo Ping Chiu; Jun Liu; Chia Lin Wei; Yijun Ruan

2008-01-01

422

Resonant atom-dimer relaxation in ultracold atoms  

NASA Astrophysics Data System (ADS)

Three-body systems with large scattering length display universal phenomena associated with a discrete scaling symmetry. These phenomena include resonant enhancement of three-body loss rates when an Efimov three-body resonance is at the scattering threshold. In particular, there can be resonant peaks in the atom-dimer relaxation rate for large positive scattering length. We improve upon earlier studies and calculate the atom-dimer relaxation rate as a function of temperature using a Bose-Einstein distribution for the thermal average. As input, we use calculations of the atom-dimer scattering phase shifts from effective field theory.

Helfrich, K.; Hammer, H.-W.

2009-06-01

423

Character displacement of song and morphology in African tinkerbirds  

Microsoft Academic Search

Divergence in acoustic signals between populations of animals can lead to species recognition failure, reproductive isolation, and speciation. Character displacement may facilitate coexistence of species in natural communities, yet evidence for character displace- ment in acoustic signals is scant. Here, we find evidence of character displacement in song as well as body size and bill size of 2 related African

Alexander N. G. Kirschel; Daniel T. Blumstein; Thomas B. Smith

2009-01-01

424

CHARACTER DISPLACEMENT VIA AGGRESSIVE INTERFERENCE IN APPALACHIAN SALAMANDERS  

Microsoft Academic Search

Ecological character displacement occurs when sympatric species compete with one another, resulting in morphological divergence. Theoretically, character displace- ment can evolve from a number of ecological interactions, such as exploitation, interference, or predation, but most examples describe species competing exploitatively for limiting resources (typically food). Here I report a case of character displacement evolving from aggressive behavioral interference, found in

Dean C. Adams

2004-01-01

425

Reconsidering the Displacement Hypothesis: Television's Influence on Children's Time Use.  

ERIC Educational Resources Information Center

|Reexamines assumptions about the displacement mechanism, which states that television displaces other activities. Considers strengths and weaknesses of various methodologies used to test the displacement hypothesis. Examines data from an eight-year panel study of the introduction of television to South Africa. Uses a variety of methodologies to…

Mutz, Diana C.; And Others

1993-01-01

426

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

427

Conflict, displacement and health in the Middle East  

Microsoft Academic Search

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

Hani Mowafi

2011-01-01

428

A review of the recent empirical literature on displaced workers  

Microsoft Academic Search

This article reviews the empirical literature on job displacement. Job displacement is widespread and strongly countercyclical (tending to peak during economic downturns), but concentrated in industries and states that are doing poorly, relative either to other industries and states or to their own prior performance. Displaced workers experience more nonemployment than do nondisplaced workers, but the difference fades after about

Bruce C. Fallick

1996-01-01

429

Multilayer atom chips for versatile atom micromanipulation  

SciTech Connect

We employ a combination of optical and electron-beam lithography to create an atom chip combining submicron wire structures with larger conventional wires on a single substrate. The multilayer fabrication enables crossed wire configurations, greatly enhancing the flexibility in designing potentials for ultracold quantum gases and Bose-Einstein condensates. Large current densities of >6x10{sup 7} A/cm{sup 2} and high voltages of up to 65 V across 0.3 {mu}m gaps are supported by even the smallest wire structures. We experimentally demonstrate the flexibility of the next generation atom chip by producing Bose-Einstein condensates in magnetic traps created by a combination of wires involving all different fabrication methods and structure sizes.

Trinker, M.; Haslinger, S.; Manz, S.; Betz, T.; Schneider, S.; Schumm, T. [Atominstitut, Vienna University of Technology, 1020 Vienna (Austria); Groth, S. [Physikalisches Institut, Universitaet Heidelberg, 69120 Heidelberg (Germany); Bar-Joseph, I. [Department of Condensed Matter Physics, Weizmann Institute of Science, Rehovot 76100 (Israel); Schmiedmayer, J. [Atominstitut, Vienna University of Technology, 1020 Vienna (Austria); Physikalisches Institut, Universitaet Heidelberg, 69120 Heidelberg (Germany)

2008-06-23

430

Experiments in cold atom optics towards precision atom interferometry  

NASA Astrophysics Data System (ADS)

Atom optics has been a highly active field of research with many scientific breakthroughs over the past two decades, largely due to successful advances in laser technology, microfabrication techniques, and the development of laser cooling and trapping of neutral atoms. This dissertation details several atom optics experiments with the motivation to develop tools and techniques for precision atom wave interferometry. It provides background information about atom optics and the fundamentals behind laser cooling and trapping, including basic techniques for cold gas thermometry and absorptive detection of atoms. A brief overview of magnetic trapping and guiding in tight wire-based traps is also provided before the experimental details are presented. We developed a novel laser source of 780 nm light using frequency-doubled 1560 nm fiber amplifier. This laser system provided up to a Watt of tunable frequency stabilized light for two Rb laser cooling and trapping experiments. One system generates Bose-Einstein condensates in an optical trap while the second is based on atom chip magnetic traps. The atom chip system, detailed in this thesis, was designed and built to develop the tools necessary for transport and loading large numbers of cold atoms and explore the potential for guided atom interferometry. Techniques and results from this experiment are presented, including an efficient magnetic transport and loading method to deliver cold atom to atom chip traps. We also developed a modeling tool for the magnetic fields formed by coiled wire geometries, as well as planar wire patterns. These models helped us design traps and determine adiabatic transportation of cold atoms between macro-scale traps and micro-traps formed on atom chips. Having achieved near unity transfer efficiency, we demonstrated that this approach promises to be a consistent method for loading large numbers of atoms into micro-traps. Furthermore, we discuss an in situ imaging technique to investigate magnetic field contours of the traps and the dynamics of atoms within those confining potentials. We also controlled the propagation along the atom chip guides by accelerating atoms with longitudinal magnetic gradients, and investigated an atom focusing scheme. While the atom chip wire guides perform a role analogous to optical fibers guiding light waves, "free space" cold atoms offer great opportunity for precision interferometry. We describe a second on-going atom optics experiment that measures gravity gradients using a pair of atom fountain interferometers separated by one meter. We have demonstrated Gravity Gradiometer resolution down to 4x10-9 g/m using a 40 kg test mass. The atomic physics subsystem is described in detail, including the vacuum, cold atom source, optics, magnetic coils and shields, and vibration isolation and compensation. The system is designed to be a compact, robust, transportable instrument, taking strides towards future gravity gradient measurements in the field. In the realm of space applications, there has been interest for micro-gravity science experiments aboard the International Space Station, along with instrument development for gravity mapping of Earth and planetary bodies with satellite-based instruments. Furthermore, there are ground-based applications for gravity imaging of local density distributions, precision measurement of gravity, as well as proposals for redefining the kilogram, detecting gravitational waves and determining the Gravitational constant.

Aveline, David C.

431

Atom Interferometry  

SciTech Connect

Atom de Broglie wave interferometry has emerged as a tool capable of addressing a diverse set of questions in gravitational and condensed matter physics, and as an enabling technology for advanced sensors in geodesy and navigation. This talk will review basic principles, then discuss recent applications and future directions. Scientific applications to be discussed include measurement of G (Newton's constant), tests of the Equivalence Principle and post-Newtonian gravity, and study of the Kosterlitz-Thouless phase transition in layered superfluids. Technology applications include development of precision gyroscopes and gravity gradiometers. The talk will conclude with speculative remarks looking to the future: Can atom interference methods be used to detect gravity waves? Can non-classical (entangled/squeezed state) atom sources lead to meaningful sensor performance improvements?

Kasevich, Mark (Stanford University)

2008-05-08

432

Estimating multiphase flow functions from displacement experiments  

SciTech Connect

A method to obtain accurate estimates of relative permeability functions from low flood rate dynamic displacement data is presented. The simultaneous estimation of the capillary pressure function from this data is also discussed. These functions are estimated using a regression-based approach by parameter estimation with a numerical coreflood simulator. Pressure drop and production data are matched with the coreflood simulator. This estimation problem is solved through minimization of the appropriate weighted least-square objective function. Careful consideration is given to the functional representation of the relative permeability and capillary pressure functions so that the most accurate estimates of those properties can be obtained.

Richmond, P.C.; Watson, A.T. (Texas A and M Univ., College Station, TX (US))

1988-01-01

433

Atomic Orbitals  

NSDL National Science Digital Library

The Atomic Orbitals Web site "was established as part of an (ongoing) project at Purdue University to develop 'visualization modules' for general chemistry students." Using the Chime plug-in, which allows unique and stunning visualizations, visitors can learn what an atomic orbital is; what the 1s, 2s, 3s, 2p, 3p, and 3d orbitals are; what hybrid orbitals are; and more. The combination of easy-to-read descriptions and educational graphics make the site a great learning resource for high school and even college level chemistry students.

2007-06-05

434

Mechanisms of In Situ Rock Displacement During Hypervelocity Impact: Field and Microscopic Observations  

NASA Astrophysics Data System (ADS)

The nature of rock deformation due to hypervelocity impact is discussed, especially with regard to the larger terrestrial structures (e.g., Sudbury, Vredefort, Manicouagan). Based on field observations and thin section microscopy, evidence is presented for two end-members of rock response to extreme strain rates: (1) bulk deformation, due to pervasive fracture generation and ensuing micro-displacement with melting; (2) localized large-displacement faulting, accompanied by friction melt generation (pseudotachylytes). There is no evidence for bulk "fluidization" at the thin section scale, except where bulk melting has occurred during impact melt sheet generation, wherein truly fluid (igneous) rocks are formed.

Spray, J. G.

2003-02-01

435

Integrated microinterferometric sensor for in-plane displacement measurement.  

PubMed

We present an integrated sensor based on a grating interferometer (GI) for in-plane displacement measurement in microregions of large engineering structures. The system concept and design, based on a monolithic version of Czarnek's GI, is discussed in detail. The technology chain of the GI measurement head (MH), including the master fabrication and further replication by means of hot embossing, is described. The numerical analyses of the MH by means of geometric ray tracing and scalar wave propagation are provided. They allow us to determine geometrical tolerance values as well as refractive index homogeneity and nonflatness of MH working surfaces, which provide proper beam guiding. Finally the demonstrative measurement performed with a model of the sensor is presented. PMID:21068855

Kr??el, Jerzy; Kujawi?ska, Ma?gorzata; Mohr, Jürgen; Guttmann, Markus; Wissmann, Markus; Tonchev, Svetlen; Parriaux, Olivier

2010-11-10

436

Integrated microinterferometric sensor for in-plane displacement measurement  

SciTech Connect

We present an integrated sensor based on a grating interferometer (GI) for in-plane displacement measurement in microregions of large engineering structures. The system concept and design, based on a monolithic version of Czarnek's GI, is discussed in detail. The technology chain of the GI measurement head (MH), including the master fabrication and further replication by means of hot embossing, is described. The numerical analyses of the MH by means of geometric ray tracing and scalar wave propagation are provided. They allow us to determine geometrical tolerance values as well as refractive index homogeneity and nonflatness of MH working surfaces, which provide proper beam guiding. Finally the demonstrative measurement performed with a model of the sensor is presented.

Krezel, Jerzy; Kujawinska, Malgorzata; Mohr, Juergen; Guttmann, Markus; Wissmann, Markus; Tonchev, Svetlen; Parriaux, Olivier

2010-11-10

437

Molecule-displacive ferroelectricity in organic supramolecular solids  

PubMed Central

Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N?-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10?kHz), and high performance in polarization switching up to 1 × 106 times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.

Ye, Heng-Yun; Zhang, Yi; Noro, Shin-ichiro; Kubo, Kazuya; Yoshitake, Masashi; Liu, Zun-Qi; Cai, Hong-Ling; Fu, Da-Wei; Yoshikawa, Hirofumi; Awaga, Kunio; Xiong, Ren-Gen; Nakamura, Takayoshi

2013-01-01

438

Fabry-Pérot interferometry for long range displacement sensing  

NASA Astrophysics Data System (ADS)

We investigate different optical configurations of a low-finesse Fabry-Pérot interferometer used for displacement sensing. The different configurations of the Fabry-Pérot cavity are selected in order to achieve large measurement ranges and angular alignment tolerances and to make the interferometer applicable for targets of various reflectivity ranges. The possible working ranges and angular alignment tolerances are characterized with respect to the interference contrast which is a measure for the signal quality. The use of a confocal arrangement enables a measurement range of up to about 0.4 m, or to work with an angular tolerance of more than +/-0.2\\convolu. In order to predict the optical response of arbitrary configurations of the Fabry-Pérot interferometer, we introduce a simulation method based on the Airy formula and the fiber optic coupling efficiency.

Thurner, Klaus; Braun, Pierre-François; Karrai, Khaled

2013-09-01

439

Molecule-displacive ferroelectricity in organic supramolecular solids  

NASA Astrophysics Data System (ADS)

Ferroelectricity is essential to many forms of current technology, ranging from sensors and actuators to optical or memory devices. In this circumstance, organic ferroelectrics are of particular importance because of their potential application in tomorrow's organic devices, and several pure organic ferroelectrics have been recently developed. However, some problems, such as current leakage and/or low working frequencies, make their application prospects especially for ferroelectric memory (FeRAM) not clear. Here, we describe the molecule-displacive ferroelectricity of supramolecular adducts of tartaric acid and 1,4-diazabicyclo[2.2.2]octane N,N'-dioxide. The adducts show large spontaneous polarization, high rectangularity of the ferroelectric hysteresis loops even at high operation frequency (10 kHz), and high performance in polarization switching up to 1 × 106 times without showing fatigue. It opens great perspectives in terms of applications, especially in organic FeRAM.

Ye, Heng-Yun; Zhang, Yi; Noro, Shin-Ichiro; Kubo, Kazuya; Yoshitake, Masashi; Liu, Zun-Qi; Cai, Hong-Ling; Fu, Da-Wei; Yoshikawa, Hirofumi; Awaga, Kunio; Xiong, Ren-Gen; Nakamura, Takayoshi

2013-07-01

440

Moral Reasoning in Violent Contexts: Displaced and Non-Displaced Colombian Children's Evaluations of Moral Transgressions, Retaliation, and Reconciliation  

ERIC Educational Resources Information Center

|In order to assess the effects of displacement and exposure to violence on children's moral reasoning, Colombian children exposed to minimal violence (non-displaced or low risk; N = 99) and to extreme violence (displaced or high risk; N = 94), evenly divided by gender at 6, 9, and 12 years of age, were interviewed regarding their evaluation of…

Ardila-Rey, Alicia; Killen, Melanie; Brenick, Alaina

2009-01-01

441

Moral Reasoning in Violent Contexts: Displaced and Non-Displaced Colombian Children's Evaluations of Moral Transgressions, Retaliation, and Reconciliation  

ERIC Educational Resources Information Center

In order to assess the effects of displacement and exposure to violence on children's moral reasoning, Colombian children exposed to minimal violence (non-displaced or low risk; N = 99) and to extreme violence (displaced or high risk; N = 94), evenly divided by gender at 6, 9, and 12 years of age, were interviewed regarding their evaluation of…

Ardila-Rey, Alicia; Killen, Melanie; Brenick, Alaina

2009-01-01

442

Displaced homemakers self-sufficiency assistance Act [15 November 1990].  

PubMed

On November 15, 1990, the US enacted the Displaced Homemakers Self-Sufficiency Assistance Act to establish a program to assist in the provision of services to displaced homemakers. Under this Act, each state will receive one competitive grant each fiscal year to 1) provide services to displaced homemakers (including referral services, career counseling, testing and evaluation, basic skills, literacy and bilingual training, recruitment and outreach, as well as job development and placement) and 2) set up statewide model and demonstration projects to serve rural displaced homemakers, minority displaced homemakers, women 40 and older, and provide for nontraditional or self-employment training. PMID:12177846

1990-01-01

443

Fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap  

SciTech Connect

We demonstrate a fast production of large {sup 23}Na Bose-Einstein condensates in an optically plugged magnetic quadrupole trap. A single global minimum of the trapping potential is generated by slightly displacing the plug beam from the center of the quadrupole field. With a dark magneto-optical trap and a simple rf evaporation, our system produces a condensate with N{approx_equal}10{sup 7} atoms every 17 s. The Majorana loss rates and the resultant heating rates for various temperatures are measured with and without plugging. The average energy of a spin-flipped atom is almost linearly proportional to temperature and determined to be about 60% of the average energy of a trapped atom. We present a numerical study of the evaporation dynamics in a plugged linear trap.

Heo, Myoung-Sun; Choi, Jae-yoon; Shin, Yong-il [Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of)

2011-01-15

444

Transient digitizer with displacement current samplers  

DOEpatents

A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board.

McEwan, Thomas E. (Livermore, CA)

1996-01-01

445

Transient digitizer with displacement current samplers  

DOEpatents

A low component count, high speed sample gate, and digitizer architecture using the sample gates is based on use of a signal transmission line, a strobe transmission line and a plurality of sample gates connected to the sample transmission line at a plurality of positions. The sample gates include a strobe pickoff structure near the strobe transmission line which generates a charge displacement current in response to propagation of the strobe signal on the strobe transmission line sufficient to trigger the sample gate. The sample gate comprises a two-diode sampling bridge and is connected to a meandered signal transmission line at one end and to a charge-holding cap at the other. The common cathodes are reverse biased. A voltage step is propagated down the strobe transmission line. As the step propagates past a capacitive pickoff, displacement current i=c(dv/dT), flows into the cathodes, driving the bridge into conduction and thereby charging the charge-holding capacitor to a value related to the signal. A charge amplifier converts the charge on the charge-holding capacitor to an output voltage. The sampler is mounted on a printed circuit board, and the sample transmission line and strobe transmission line comprise coplanar microstrips formed on a surface of the substrate. Also, the strobe pickoff structure may comprise a planar pad adjacent the strobe transmission line on the printed circuit board. 16 figs.

McEwan, T.E.

1996-05-21

446

Statistical analysis of undersampled dynamic displacement measurements  

NASA Astrophysics Data System (ADS)

The Lutrive highway bridges are two twin bridges built in 1972 by the cantilever method with mid-span articulations. The bridge deck consists of a box girder of variable depth. In 1997 this bridge was instrumented with 30 SOFO fiber optic deformation sensors installed inside the box girder. This sensor network is mainly aimed at measuring the short- and long-term spatial displacements of one of the spans. This includes the displacement resulting from the daily variations of temperature and the long-term creep effects. It was found that these same sensors could also be used to capture the quasi-static part of the dynamic deformation of the bridge under traffic load. Although the measurement system can acquire measurements only at intervals a few seconds apart, it was found that these 'snapshots' could give interesting information about the low frequency quasi-static deformations of the bridge. The data from pair of sensors was combined to obtain information about the instantaneous curvature variations of the bridge. This curvature data was then analyzed statistically to extract information about the dynamic traffic loads. This measurement and analysis method was validated in a fatigue test on a concrete slab.

Inaudi, Daniele; Conte, Joel P.; Perregaux, Nicholas; Vurpillot, Samuel

1998-06-01

447

Do alternative energy sources displace fossil fuels?  

NASA Astrophysics Data System (ADS)

A fundamental, generally implicit, assumption of the Intergovernmental Panel on Climate Change reports and many energy analysts is that each unit of energy supplied by non-fossil-fuel sources takes the place of a unit of energy supplied by fossil-fuel sources. However, owing to the complexity of economic systems and human behaviour, it is often the case that changes aimed at reducing one type of resource consumption, either through improvements in efficiency of use or by developing substitutes, do not lead to the intended outcome when net effects are considered. Here, I show that the average pattern across most nations of the world over the past fifty years is one where each unit of total national energy use from non-fossil-fuel sources displaced less than one-quarter of a unit of fossil-fuel energy use and, focusing specifically on electricity, each unit of electricity generated by non-fossil-fuel sources displaced less than one-tenth of a unit of fossil-fuel-generated electricity. These results challenge conventional thinking in that they indicate that suppressing the use of fossil fuel will require c