Finite Difference Elastic Wave Modeling Including Surface Topography
Al Muhaidib, Abdulaziz
2011-01-01T23:59:59.000Z
Surface topography and the weathered zone (i.e., heterogeneity near the earth’s surface) have great effects on elastic wave propagation. Both surface waves and body waves are contaminated by scattering and conversion by ...
Propagation of elastic waves through a lattice of cylindrical cavities
Propagation of elastic waves through a lattice of cylindrical cavities By S. Guo & P. Mc asymptotic homogenization to obtain low-frequency approximations to elastic wave propagation through periodic follows that of McIver (2007) who investigates acoustic-wave propagation through a lattice of rigid
Love wave propagation in layered magneto-electro-elastic structures
Wang, Ji
Love wave propagation in layered magneto-electro-elastic structures with initial stress J. Du, X that the initial stress has an important effect on the Love wave propagation in layered piezomagnetic at their interface. He concluded that shear surface waves propagate in the layer and attenuate along the thickness
Vel, Senthil
-rich, crustal rocks. We calculated the bulk elastic properties and resulting wave velocities for rock samplesThe influence of crenulation cleavage development on the bulk elastic and seismic properties of phyllosilicate-rich rocks Félice M.J. Naus-Thijssen a, , Andrew J. Goupee b , Scott E. Johnson a , Senthil S. Vel
Pavel Galich; Stephan Rudykh
2014-12-31T23:59:59.000Z
We analyze the propagation of elastic waves in soft materials subjected to finite deformations. We derive explicit dispersion relations, and apply these results to study elastic wave propagation in (i) nearly incompressible materials such as biological tissues and polymers, and (ii) negative Poisson's ratio or auxetic materials. We find that for nearly incompressible materials transverse wave velocities exhibit strong dependence on direction of propagation and initial strain state, whereas the longitudinal component is not affected significantly until extreme levels of deformations are attained. For highly compressible materials, we show that both pressure and shear wave velocities depend strongly on initial deformation and direction of propagation. When compression is applied, longitudinal wave velocity decreases in positive bulk modulus materials, and increases for negative bulk modulus materials; this is regardless the direction of wave prorogation. We demonstrate that finite deformations influence elastic wave propagation through combinations of induced effective compressibility and stiffness.
Elastic Wave Behavior Across Linear Slip Interfaces
Schoenberg, M.
plane waves incident at arbitrary angles upon a plane linear slip interface are computed ... Also included in these sections is an analysis ... ish, Ut is of the form.
Measurements of elastic modulus using laser-induced surface waves
Chang, D.J.; Amimoto, S.T.; Gross, R.W.F. [Aerospace Corporation, Los Angeles, CA (United States); Glenn, T. [Massachusetts Institute of Technology, Cambridge, MA (United States)
1995-12-31T23:59:59.000Z
In general, the mechanical testing methods that are utilized for alloys and polymers, e.g., dogbone, rheovibron, etc., are not applicable to thin film structures. We wish to report noncontacting measurements of the surface acoustic wave (SAW) velocity and the elastic modulus applicable to thin films of moderate thickness. An accompanying paper extends this technique to smaller film dimensions. A 15 ns pulsed YAG laser was used as the energy source to thermoelastically excite surface waves. The propagation of the waves was then observed by a second, independent He-Ne laser at a distance from the excitation spot. using the knife edge/beam deflection technique. A cylindrical lens was used to reduce the energy loading of the YAG laser on the sample to avoid damaging the surface of the specimen. The Rayleigh wave velocity is calculated from measurements of the arrival time of the surface wave as a function of distance from the ND:YAG laser spot. The shear modulus, G, can be determined from the measured speed of the surface waves, V, the specimen density, p, and Poisson`s ratio, v, according to the following relationship: V = R(v){sm_bullet}(G/p){sup {1/2}} where R(v), expressed as (0.862 + 1.14v)/(l + v), is the ratio of the Rayleigh wave velocity to the shear wave velocity and ranges from 0.86 to 0.95 Table below lists the measured surface wave velocities and the calculated shear modulus for our experimental results and the published values. Excellent agreement is observed. The depth of the SAW is approximately equal to the SAW wavelength which is approximately the laser spot size. Typically 30 {mu}m spot sizes can be readily achieved. In conclusion, SAW velocities and the modulus of elasticity of various materials have been measured. We have demonstrated that this non-contacting method can be used to characterize moderately thin films.
Spherical Wave Propagation in a Nonlinear Elastic Medium
Korneev, Valeri A.
2009-07-01T23:59:59.000Z
Nonlinear propagation of spherical waves generated by a point-pressure source is considered for the cases of monochromatic and impulse primary waveforms. The nonlinear five-constant elastic theory advanced by Murnaghan is used where general equations of motion are put in the form of vector operators, which are independent of the coordinate system choice. The ratio of the nonlinear field component to the primary wave in the far field is proportional to ln(r) where r is a propagation distance. Near-field components of the primary field do not contribute to the far field of nonlinear component.
Weak and strong wave turbulence spectra for elastic thin plate
Naoto Yokoyama; Masanori Takaoka
2013-02-15T23:59:59.000Z
Variety of statistically steady energy spectra in elastic wave turbulence have been reported in numerical simulations, experiments, and theoretical studies. Focusing on the energy levels of the system, we have performed direct numerical simulations according to the F\\"{o}ppl--von K\\'{a}rm\\'{a}n equation, and successfully reproduced the variability of the energy spectra by changing the magnitude of external force systematically. When the total energies in wave fields are small, the energy spectra are close to a statistically steady solution of the kinetic equation in the weak turbulence theory. On the other hand, in large-energy wave fields, another self-similar spectrum is found. Coexistence of the weakly nonlinear spectrum in large wavenumbers and the strongly nonlinear spectrum in small wavenumbers are also found in moderate energy wave fields.
Super-Elastic and Plastic Shock Waves Generated by Lasers N.A. Inogamov a,1
Fominov, Yakov
Super-Elastic and Plastic Shock Waves Generated by Lasers N.A. Inogamov a,1 , V.V. Zhakhovsky b,3 fortov@ihed.ras.ru, i oleynik@usf.edu Keywords: Femtosecond laser-matter interactions, elastic-plastic there is an elastic shock wave (SW), which propagates before the strong plastic shock with plastic pressures of up
Numerical modeling of elastic wave scattering by near-surface heterogeneities
Al Muhaidib, Abdulaziz
2013-01-01T23:59:59.000Z
A perturbation method for elastic waves and numerical forward modeling are used to calculate the effects of seismic wave scattering from arbitrary shape shallow subsurface heterogeneities. Wave propagation is simulated ...
Rayleigh scattering and nonlinear inversion of elastic waves
Gritto, R.
1995-12-01T23:59:59.000Z
Rayleigh scattering of elastic waves by an inclusion is investigated and the limitations determined. In the near field of the inhomogeneity, the scattered waves are up to a factor of 300 stronger than in the far field, excluding the application of the far field Rayleigh approximation for this range. The investigation of the relative error as a function of parameter perturbation shows a range of applicability broader than previously assumed, with errors of 37% and 17% for perturbations of {minus}100% and +100%, respectively. The validity range for the Rayleigh limit is controlled by large inequalities, and therefore, the exact limit is determined as a function of various parameter configurations, resulting in surprisingly high values of up to k{sub p}R = 0.9. The nonlinear scattering problem can be solved by inverting for equivalent source terms (moments) of the scatterer, before the elastic parameters are determined. The nonlinear dependence between the moments and the elastic parameters reveals a strong asymmetry around the origin, which will produce different results for weak scattering approximations depending on the sign of the anomaly. Numerical modeling of cross hole situations shows that near field terms are important to yield correct estimates of the inhomogeneities in the vicinity of the receivers, while a few well positioned sources and receivers considerably increase the angular coverage, and thus the model resolution of the inversion parameters. The pattern of scattered energy by an inhomogeneity is complicated and varies depending on the object, the wavelength of the incident wave, and the elastic parameters involved. Therefore, it is necessary to investigate the direction of scattered amplitudes to determine the best survey geometry.
- static stress).1 For isotropic materials, the speed of sound change with stress levels allows onePump and probe waves in dynamic acousto-elasticity: Comprehensive description and comparison with nonlinear elastic theories J. Rivie`re,1,a) G. Renaud,2 R. A. Guyer,1,b) and P. A. Johnson1 1 Earth
Journal of Sound and Vibration 298 (2006) 108131 Elastic wave radiation from a high frequency
Abrahams, I. David
JOURNAL OF SOUND AND VIBRATION Journal of Sound and Vibration 298 (2006) 108Â131 Elastic wave. Introduction Problems concerning the propagation, refraction and diffraction of waves are the subject method to detect defects is to analyse the scattering of the elastic waves generated by ultrasonic
Continued Fraction Absorbing Boundary Conditions for Transient Elastic Wave Propagation Modeling
Guddati, Murthy N.
Continued Fraction Absorbing Boundary Conditions for Transient Elastic Wave Propagation Modeling Md of the truncated exterior. Development of an accurate ABC for transient elastic wave propagation problems are obtained by factoring the wave equation into outward and inward propagating operators and permitting only
Double porosity modeling in elastic wave propagation for reservoir characterization
Berryman, J. G., LLNL
1998-06-01T23:59:59.000Z
Phenomenological equations for the poroelastic behavior of a double porosity medium have been formulated and the coefficients in these linear equations identified. The generalization from a single porosity model increases the number of independent coefficients from three to six for an isotropic applied stress. In a quasistatic analysis, the physical interpretations are based upon considerations of extremes in both spatial and temporal scales. The limit of very short times is the one most relevant for wave propagation, and in this case both matrix porosity and fractures behave in an undrained fashion. For the very long times more relevant for reservoir drawdown,the double porosity medium behaves as an equivalent single porosity medium At the macroscopic spatial level, the pertinent parameters (such as the total compressibility) may be determined by appropriate field tests. At the mesoscopic scale pertinent parameters of the rock matrix can be determined directly through laboratory measurements on core, and the compressibility can be measured for a single fracture. We show explicitly how to generalize the quasistatic results to incorporate wave propagation effects and how effects that are usually attributed to squirt flow under partially saturated conditions can be explained alternatively in terms of the double-porosity model. The result is therefore a theory that generalizes, but is completely consistent with, Biot`s theory of poroelasticity and is valid for analysis of elastic wave data from highly fractured reservoirs.
Journal of Mining Science, Vol. 45, No. 5, 2009 MODELING THE ELASTIC WAVE PROPAGATION
Alexandrov, Victor
427 Journal of Mining Science, Vol. 45, No. 5, 2009 MODELING THE ELASTIC WAVE PROPAGATION UDC 622.7 + 622 The wave propagation analysis revealed that the low-frequency pendulum wave propagating in a 2D block medium with periodic structure due to the action of local impulse has a two-wave
Interaction of gravitational waves with an elastic solid medium
B. Carter
2001-02-28T23:59:59.000Z
Contents. 1. Introduction. 2. Kinematics of a Material Medium: Material Representation. 3. Kinematics of a Material Medium: Convected Differentials. 4. Kinematics of a Perfect Elastic Medium. 5. Small Gravitational Perturbations of an Elastic Medium.
Numerical modeling of wave propagation in random anisotropic heterogeneous elastic media
Boyer, Edmond
Numerical modeling of wave propagation in random anisotropic heterogeneous elastic media Q.-A. Ta numerical experiments that were performed on wave propagation in a randomly generated anisotropic used for the propagation of waves in geophysical media are not compatible with the surface recordings
Multiscale Method for Elastic Wave Propagation in the Heterogeneous, Anisotropic Media
Gao, Kai
2014-08-05T23:59:59.000Z
FEM) for elastic wave propagation in heterogeneous, anisotropic media in both continuous Galerkin (CG) and discontinuous Galerkin (DG) formulations. The advantage of the multiscale basis functions is they are model-dependent, unlike the predefined polynomial basis...
Geophysical Prospecting 31,265-292, 1983. REFLECTION OF ELASTIC WAVES FROM
Santos, Juan
Geophysical Prospecting 31,265-292, 1983. REFLECTION OF ELASTIC WAVES FROM PERIODICALLY STRATIFIED from Periodically Stratified Media with Interfacial Slip, Geophysical Prospecting 31 phase propagation in some other direction. INTRODUCTION Geophysical media often exhibit anisotropic
Circumferential creeping waves around a fluid-filled cylindrical cavity in an elastic medium
Nagy, Peter B.
of fluid fuel trapped in these rather small approximately 67 mm in diameter holes would strongly affectCircumferential creeping waves around a fluid-filled cylindrical cavity in an elastic medium Waled The dispersion behavior of circumferential creeping waves around a fluid-filled cylindrical cavity in an infinite
The waves of damage in elastic-plastic lattices with waiting links: design and simulation
Cherkaev, Andrej
The waves of damage in elastic-plastic lattices with waiting links: design and simulation A damage (a neck) in an element, initiating the damage instead in another sequen- tial element. A wave of "partial damage" propagates through the chain, as all the links develop necks but do not fail. When
Analytical modeling of elastic-plastic wave behavior near grain boundaries in crystalline materials
Loomis, Eric [Los Alamos National Laboratory; Greenfield, Scott [Los Alamos National Laboratory; Luo, Shengnian [Los Alamos National Laboratory; Swift, Damian [LLNL; Peralta, Pedro [ASU
2009-01-01T23:59:59.000Z
It is well known that changes in material properties across an interface will produce differences in the behavior of reflected and transmitted waves. This is seen frequently in planar impact experiments, and to a lesser extent, oblique impacts. In anisotropic elastic materials, wave behavior as a function of direction is usually accomplished with the aid of velocity surfaces, a graphical method for predicting wave scattering configurations. They have expanded this method to account for inelastic deformation due to crystal plasticity. The set of derived equations could not be put into a characteristic form, but instead led to an implicit problem. to overcome this difficulty an algorithm was developed to search the parameters space defined by a wave normal vector, particle velocity vector, and a wave speed. A solution was said to exist when a set from this parameter space satisfied the governing vector equation. Using this technique they can predict the anisotropic elastic-plastic velocity surfaces and grain boundary scattering configuration for crystalline materials undergoing deformation by slip. Specifically, they have calculated the configuration of scattered elastic-plastic waves in anisotropic NiAl for an incident compressional wave propagating along a <111> direction and contacting a 45 degree inclined grain boundary and found that large amplitude transmitted waves exist owing to the fact that the wave surface geometry forces it to propagate near the zero Schmid factor direction <100>.
Effective medium theory of elastic waves in random networks of rods
J. I. Katz; J. J. Hoffman; M. S. Conradi; J. G. Miller
2012-06-13T23:59:59.000Z
We formulate an effective medium (mean field) theory of a material consisting of randomly distributed nodes connected by straight slender rods, hinged at the nodes. Defining novel wavelength-dependent effective elastic moduli, we calculate both the static moduli and the dispersion relations of ultrasonic longitudinal and transverse elastic waves. At finite wave vector $k$ the waves are dispersive, with phase and group velocities decreasing with increasing wave vector. These results are directly applicable to networks with empty pore space. They also describe the solid matrix in two-component (Biot) theories of fluid-filled porous media. We suggest the possibility of low density materials with higher ratios of stiffness and strength to density than those of foams, aerogels or trabecular bone.
Two-dimensional elastic wave propagation in a duraluminum sheet
Cefola, David Paul
1982-01-01T23:59:59.000Z
MENTAL PROCEDURE Experimental Design Data Acquisition Data Correction III. DATA PROCESSING 12 12 12 15 16 Wiener Filter Theory Construction of Desired. Wavelet 23 25 Wiener Filter Results 27 Bandpass Filter IV. TRAVELTIME ANALYSIS Wave... perpendicular to strike 2, Duraluminum model used in experiments 1 and 2 Relations between the Rayleigh-, P-, and S-wave velocities in an infinite medium for Poisson's ratio, o-, ranging from 0. 0 to 0. 5 Square root of energy ratios for reflected P- and S-waves...
Geophysical Prospecting 36,571-590,1988 ELASTIC WAVE PROPAGATION IN MEDIA WITH
Santos, Juan
Geophysical Prospecting 36,571-590,1988 ELASTIC WAVE PROPAGATION IN MEDIA WITH PARALLEL FRACTURES propagation in media with parallel frac- tures and aligned cracks. Geophysical Prospecting 36,571-590. A model,CT 06877-4108, USA. Institute for Earth Sciences, Department of Geophysics, PB 80021, 3508 TA Utrecht
An energy absorbing far-field boundary condition for the elastic wave equation
Petersson, N A; Sjogreen, B
2008-07-15T23:59:59.000Z
The authors present an energy absorbing non-reflecting boundary condition of Clayton-Engquist type for the elastic wave equation together with a discretization which is stable for any ratio of compressional to shear wave speed. They prove stability for a second order accurate finite-difference discretization of the elastic wave equation in three space dimensions together with a discretization of the proposed non-reflecting boundary condition. The stability proof is based on a discrete energy estimate and is valid for heterogeneous materials. The proof includes all six boundaries of the computational domain where special discretizations are needed at the edges and corners. The stability proof holds also when a free surface boundary condition is imposed on some sides of the computational domain.
Fourier analysis of wave turbulence in a thin elastic plate
Nicolas Mordant
2010-06-18T23:59:59.000Z
The spatio-temporal dynamics of the deformation of a vibrated plate is measured by a high speed Fourier transform profilometry technique. The space-time Fourier spectrum is analyzed. It displays a behavior consistent with the premises of the Weak Turbulence theory. A isotropic continuous spectrum of waves is excited with a non linear dispersion relation slightly shifted from the linear dispersion relation. The spectral width of the dispersion relation is also measured. The non linearity of this system is weak as expected from the theory. Finite size effects are discussed. Despite a qualitative agreement with the theory, a quantitative mismatch is observed which origin may be due to the dissipation that ultimately absorbs the energy flux of the Kolmogorov-Zakharov casade.
Zaretsky, E. B. [Department of Mechanical Engineering, Ben Gurion University, 84105 Beer Sheva (Israel); Kanel, G. I. [Joint Institute for High Temperatures RAS, Izhorskaya 13, bld.2, 125412 Moscow (Russian Federation)
2014-06-28T23:59:59.000Z
The evolution of the elastic precursor waves in pure tantalum and vanadium is presented at normal and elevated temperatures over propagation distances that ranged from 0.125 to 3?mm. Measurements were performed in order to obtain experimental data about the temperature-rate dependence of the yield stress of the two metals. With increasing propagation distance, the rate of the decay of elastic precursor decreases, as the shear stress in the elastic precursor wave approaches the Peierls stresses. It has been found that the decay, with propagation distance, of the post-spike minimum of the spike-like elastic precursor wave in vanadium is essentially non-monotonous. The experiments also revealed that annealing of tantalum and vanadium increases their Hugoniot elastic limit. The anomalous increase of the high strain rate yield stress with temperature, as observed earlier for some FCC and HCP metals, has not been detected in these measurements.
Johnson, P.A.; McCall, K.R.; Meegan, G.D. Jr. [Los Alamos National Lab., NM (United States)
1993-11-01T23:59:59.000Z
Experiments in rock show a large nonlinear elastic wave response, far greater than that of gases, liquids and most other solids. The large response is attributed to structural defects in rock including microcracks and grain boundaries. In the earth, a large nonlinear response may be responsible for significant spectral alteration at amplitudes and distances currently considered to be well within the linear elastic regime.
Partial-wave analysis for elastic p{sup 13}C scattering at astrophysical energies
Dubovichenko, S. B., E-mail: dubovichenko@mail.ru [V.G. Fessenkov Astrophysical Institute (Kazakhstan)
2012-03-15T23:59:59.000Z
A standard partial-wave analysis was performed on the basis of known measurements of differential cross sections for elastic p{sup 13}C scattering at energies in the range 250-750 keV. This analysis revealed that, in the energy range being considered, it is sufficient to take into account the {sup 3}S{sub 1} wave alone. A potential for the triplet {sup 3}S{sub 1}-wave state of the p{sup 13}C system in the region of the J{sup p}T = 1{sup -1} resonance at 0.55 MeV was constructed on the basis of the phase shifts obtained from the aforementioned partial-wave analysis.
INFLUENCE OF SOUND WAVE STIMULATION ON THE GROWTH OF
Boyer, Edmond
INFLUENCE OF SOUND WAVE STIMULATION ON THE GROWTH OF STRAWBERRY IN SUNLIGHT GREENHOUSE Lirong Qi differences between the circumstances of the two sunlight greenhouses, the strawberry after the sound wave disease and insect pest were enhanced. The experiment results show that sound wave stimulation can
Paris-Sud XI, UniversitÃ© de
Seismic Wave Propagation in Alluvial Basins and Influence of Site-City Interaction 1 Seismic Wave of alluvial deposits have a major influence on seismic wave propagation and amplification. However influence seismic wave propagation near the free surface. In this paper, the influence of surface structures
High-performance modeling acoustic and elastic waves using the parallel Dichotomy Algorithm
Fatyanov, Alexey G., E-mail: fat@nmsf.sscc.r [Institute of Computational Mathematics and Mathematical Geophysics, 630090 Novosibirsk (Russian Federation); Terekhov, Andrew V., E-mail: andrew.terekhov@mail.r [Institute of Computational Mathematics and Mathematical Geophysics, 630090 Novosibirsk (Russian Federation); Budker Institute of Nuclear Physics, 630090 Novosibirsk (Russian Federation); Novosibirsk State University, 630090 Novosibirsk (Russian Federation)
2011-03-01T23:59:59.000Z
A high-performance parallel algorithm is proposed for modeling the propagation of acoustic and elastic waves in inhomogeneous media. An initial boundary-value problem is replaced by a series of boundary-value problems for a constant elliptic operator and different right-hand sides via the integral Laguerre transform. It is proposed to solve difference equations by the conjugate gradient method for acoustic equations and by the GMRES(k) method for modeling elastic waves. A preconditioning operator was the Laplace operator that is inverted using the variable separation method. The novelty of the proposed algorithm is using the Dichotomy Algorithm , which was designed for solving a series of tridiagonal systems of linear equations, in the context of the preconditioning operator inversion. Via considering analytical solutions, it is shown that modeling wave processes for long instants of time requires high-resolution meshes. The proposed parallel fine-mesh algorithm enabled to solve real application seismic problems in acceptable time and with high accuracy. By solving model problems, it is demonstrated that the considered parallel algorithm possesses high performance and efficiency over a wide range of the number of processors (from 2 to 8192).
Appelo, D; Petersson, N A
2007-12-17T23:59:59.000Z
The isotropic elastic wave equation governs the propagation of seismic waves caused by earthquakes and other seismic events. It also governs the propagation of waves in solid material structures and devices, such as gas pipes, wave guides, railroad rails and disc brakes. In the vast majority of wave propagation problems arising in seismology and solid mechanics there are free surfaces. These free surfaces have, in general, complicated shapes and are rarely flat. Another feature, characterizing problems arising in these areas, is the strong heterogeneity of the media, in which the problems are posed. For example, on the characteristic length scales of seismological problems, the geological structures of the earth can be considered piecewise constant, leading to models where the values of the elastic properties are also piecewise constant. Large spatial contrasts are also found in solid mechanics devices composed of different materials welded together. The presence of curved free surfaces, together with the typical strong material heterogeneity, makes the design of stable, efficient and accurate numerical methods for the elastic wave equation challenging. Today, many different classes of numerical methods are used for the simulation of elastic waves. Early on, most of the methods were based on finite difference approximations of space and time derivatives of the equations in second order differential form (displacement formulation), see for example [1, 2]. The main problem with these early discretizations were their inability to approximate free surface boundary conditions in a stable and fully explicit manner, see e.g. [10, 11, 18, 20]. The instabilities of these early methods were especially bad for problems with materials with high ratios between the P-wave (C{sub p}) and S-wave (C{sub s}) velocities. For rectangular domains, a stable and explicit discretization of the free surface boundary conditions is presented in the paper [17] by Nilsson et al. In summary, they introduce a discretization, that use boundary-modified difference operators for the mixed derivatives in the governing equations. Nilsson et al. show that the method is second order accurate for problems with smoothly varying material properties and stable under standard CFL constraints, for arbitrarily varying material properties. In this paper we generalize the results of Nilsson et al. to curvilinear coordinate systems, allowing for simulations on non-rectangular domains. Using summation by parts techniques, we show that there exists a corresponding stable discretization of the free surface boundary condition on curvilinear grids. We also prove that the discretization is stable and energy conserving both in semi-discrete and fully discrete form. As for the Cartesian method in, [17], the stability and conservation results holds for arbitrarily varying material properties. By numerical experiments it is established that the method is second order accurate.
Partial-wave analysis of elastic {sup 4}He{sup 4}He scattering in the energy range 40-50 MeV
Dubovichenko, S. B. [Fesenkov Astrophysical Institute (Kazakhstan)], E-mail: sergey@dubovichenko.net
2008-01-15T23:59:59.000Z
A partial-wave analysis of elastic {sup 4}He{sup 4}He scattering is performed in the energy range 40-50 MeV.
Elastic-Plastic Behavior of U6Nb under Ramp Wave Loading
Hayes, D. B.; Gray, G. T. III; Hixson, R. S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hall, C. A. [Sandia National Laboratories, Albuquerque New Mexico 87185-1181 (United States)
2006-07-28T23:59:59.000Z
When uranium-niobium (6 wt.%) alloy is shock loaded, the expected elastic precursor is absent. A prior model attributed this absence to shear-induced twinning and the concomitant shear stress reduction that prevented the shocked material from reaching the plastic yield point. In the present study, carefully prepared U6Nb was subjected to shock loading to verify the adequacy of the prior model. Other samples were loaded with a ramp pressure pulse with strain rate large enough so that significant twinning would not occur during the experiment. Backward integration analyses of these latter experiments' back surface motion give stress-strain loading paths in U6Nb that suggest ordinary elastic-plastic flow. Some of the U6Nb was pre-strained by cold rolling in an effort to further ensure that twinning did not affect wave propagation. Shock and ramp loadings yielded similar results to the baseline material except, as expected, they are consistent with a higher yield stress and twinning shear stress threshold.
Variational integrators for the dynamics of thermo-elastic solids with finite speed thermal waves
Pablo Mata A; Adrian J Lew
2014-03-15T23:59:59.000Z
This paper formulates variational integrators for finite element discretizations of deformable bodies with heat conduction in the form of finite speed thermal waves. The cornerstone of the construction consists in taking advantage of the fact that the Green-Naghdi theory of type II for thermo-elastic solids has a Hamiltonian structure. Thus, standard techniques to construct variational integrators can be applied to finite element discretizations of the problem. The resulting discrete-in-time trajectories are then consistent with the laws of thermodynamics for these systems: for an isolated system, they exactly conserve the total entropy, and nearly exactly conserve the total energy over exponentially long periods of time. Moreover, linear and angular momenta are also exactly conserved whenever the exact system does. For definiteness, we construct an explicit second-order accurate algorithm for affine tetrahedral elements in two and three-dimensions, and demonstrate its performance with numerical examples.
Finite-difference schemes for elastic waves based on the integration approach
Zahradnik, J. (Charles Univ., Prague (Czech Republic). Faculty of Mathematics and Physics); O'Leary, P. (Univ. of Wyoming, Laramie, WY (United States). Dept. of Mathematics); Sochacki, J. (James Madison Univ., Harrisonburg, VA (United States). Dept. of Mathematics)
1994-06-01T23:59:59.000Z
The authors present a second order explicit finite-difference scheme for elastic waves in 2-D nonhomogeneous media. These schemes are based on integrating the equations of motion and the stress-free surface conditions across the discontinuities before discretizing them on a grid. As an alternative for the free-surface treatment, a scheme using zero density above the surface is suggested. This scheme is first order and is shown to be a natural consequence of the integrated equations of motion and is called a vacuum formalism. These schemes remove instabilities encountered in earlier integration schemes. The consistency study reveals a close link between the vacuum formalism and the integrated/discretized stress-free condition, giving priority to the vacuum formalism when a material discontinuity reaches the free surface. The two presented free-surface treatments coincide in the sense of the limit (grid size [yields] 0) for lateral homogeneity at or near the free surface.
Yoshimura, K.; Sakashita, S. [Radioactive Waste Management Funding and Research Center, Tokyo (Japan); Ando, K.; Bruines, P. [Civil Engineering Technical Division, Obayashi Corporation, Tokyo (Japan); Blechschmidt, I. [National Cooperative for the Disposal of Radioactive Waste, Wettingen (Switzerland); Kickmaier, W. [University of Applied Sciences, Northern Switzerland, Brugg (Switzerland); Onishi, Y.; Nishiyama, S. [Graduate School of Engineering, Kyoto University, Kyoto (Japan)
2007-07-01T23:59:59.000Z
The objective of this study is to establish a technique to obtain hydraulic conductivity distribution in granite rock masses using seismic tomography. We apply the characteristic that elastic wave velocity disperses in fully saturated porous media on frequency and this velocity dispersion is governed by the hydraulic conductivity - this characteristic has been confirmed in laboratory experiments. The feasibility and design of the field experiment was demonstrated in a first step with numerical simulations. In a second step we applied the technique to the fractured granite at the Grimsel Test Site in Switzerland. The emphasis of the field campaign was on the evaluation of the range of applicability of this technique. The field campaign was structured in three steps, each one corresponding to a larger spatial scale. First, the seismic tomography was applied to a small area - the two boreholes were located at a distance of 1.5 m. In the following step, we selected a larger area, in which the distance of the boreholes amounts to 10 m and the field corresponds to a more complex geology. Finally we applied the testing to a field where the borehole distance was of the order of 75 m. We also drilled a borehole to confirm hydraulic characteristic and reviewed hydraulic model in the 1.5 m cross-hole location area. The results from the field campaign are presented and their application to the various fields are discussed and evaluated. (authors)
http://rcc.its.psu.edu/hpc Influence of Temperature on Guided Wave Propagation
BjÃ¸rnstad, Ottar Nordal
http://rcc.its.psu.edu/hpc Influence of Temperature on Guided Wave Propagation Manton J. Guers Ph-established technique for studying ultrasonic wave propagation in both conventional and guided wave applications in the mechanical properties influences the guided wave propagation. In order to analysis the transient results
Gao, Kai; Gibson, Richard L; Chung, Eric T; Efendiev, Yalchin
2014-01-01T23:59:59.000Z
It is important to develop fast yet accurate numerical methods for seismic wave propagation to characterize complex geological structures and oil and gas reservoirs. However, the computational cost of conventional numerical modeling methods, such as finite-difference method and finite-element method, becomes prohibitively expensive when applied to very large models. We propose a Generalized Multiscale Generalized Multiscale Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both boundaries and the interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale medium property variations, and allows us to greatly reduce the degrees of freedom that are required to implement the modeling compared with conventional finite-element method for wave equation, while restricting the error to low values. We formulate the continuous Galerkin and di...
Long waves in water over a visco-elastic muddy seabed
Garnier, Erell-Isis
2011-01-01T23:59:59.000Z
The propagation of surface waves over a flat muddy seabed are studied. Mud is first considered as a Newtonian fluid. Water and mud equations are derived in order to obtain governing equation for surface and interface waves. ...
Appelö, Daniel
and periodic boundary conditions. The fully discrete version of the method conserves a discrete energy; curvilinear grids ; finite differences; stability; energy estimate; seismic wave propagation 1 Introduction, such as gas pipes, wave guides, railroad rails and disc brakes. In the vast majority of wave propagation
Determination of third order elastic constants in a complex solid applying coda wave interferometry
material, concrete. Concrete, a structurally heterogeneous and volumetrically mechanically damaged material nonequilibrium class3 or also the nonlinear mesoscopic class,4 and an extreme example is concrete. It is highly complex both chemically and mechani- cally, is porous and permeable, heterogeneous, and highly elastically
Sensitive imaging of an elastic nonlinear wave-scattering source in a solid Vyacheslav V. Kazakov
here, synchronous, phase lock de- tection is combined with nonlinear wave modulation for im- aging simultaneous to a group of high frequency tone bursts. Due to the cw excitation, the amplitude and phase nonlinear scattering sources. A low-frequency, continu- ous wave cw excitation is applied to the specimen
Influence of control strategy on the global efficiency of a Direct Wave Energy Converter with
Paris-Sud XI, Université de
Influence of control strategy on the global efficiency of a Direct Wave Energy Converter, France Abstract--The choice of control strategy for Direct Wave Energy Converters (DWEC) is often a simple loss model in order to design a better control strategy. Keywords--Wave energy conversion; Point
Nonlinear Shear Wave in a Non Newtonian Visco-elastic Medium
Janaki, D Banerjee M S; Chaudhuri, M
2013-01-01T23:59:59.000Z
An analysis of nonlinear transverse shear wave has been carried out on non-Newtonian viscoelastic liquid using generalized hydrodynamic(GH) model. The nonlinear viscoelastic behavior is introduced through velocity shear dependence of viscosity coefficient by well known Carreau -Bird model. The dynamical feature of this shear wave leads to the celebrated Fermi-Pasta-Ulam (FPU) problem. Numerical solution has been obtained which shows that initial periodic solutions reoccur after passing through several patterns of periodic waves. A possible explanation for this periodic solution is given by constructing modified Korteweg de Vries (mKdV) equation. This model has application from laboratory to astrophysical plasmas as well as biological systems.
Sermeus, J.; Glorieux, C., E-mail: christ.glorieux@fys.kuleuven.be [Laboratory for Acoustics and Thermal Physics, KU Leuven, University of Leuven, Celestijnenlaan 200D, B-3001 Heverlee (Belgium); Sinha, R.; Vereecken, P. M. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Center for Surface Chemistry and Catalysis, KU Leuven, University of Leuven, Kasteelpark Arenberg 23, B-3001 Leuven (Belgium); Vanstreels, K. [IMEC, Kapeldreef 75, B-3001 Leuven (Belgium)
2014-07-14T23:59:59.000Z
MnO{sub 2} is a material of interest in the development of high energy-density batteries, specifically as a coating material for internal 3D structures, thus ensuring rapid energy deployment. Its electrochemical properties have been mapped extensively, but there are, to the best of the authors' knowledge, no records of the elastic properties of thin film MnO{sub 2}. Impulsive stimulated thermal scattering (ISTS), also known as the heterodyne diffraction or transient grating technique, was used to determine the Young's modulus (E) and porosity (?) of a 500?nm thick MnO{sub 2} coating on a Si(001) substrate. ISTS is an all optical method that is able to excite and detect surface acoustic waves (SAWs) on opaque samples. From the measured SAW velocity dispersion, the Young's modulus and porosity were determined to be E?=?25?±?1?GPa and ?=42±1%, respectively. These values were confirmed by independent techniques and determined by a most-squares analysis of the carefully fitted SAW velocity dispersion. This study demonstrates the ability of the presented technique to determine the elastic parameters of a thin, porous film on an anisotropic substrate.
Culbertson, D.L.; Whitney, C.E.
1995-07-01T23:59:59.000Z
The objective of this project was to provide the gas pipeline industry with a more comprehensive understanding of the capabilities of the elastic-wave, in-line inspection system developed by British Gas (BG) for detecting stress corrosion cracking (SCC) in natural gas transmission pipelines.
Enrico Montanari; Pierluigi Fortini
1998-08-26T23:59:59.000Z
The interaction of a gravitational wave with a system made of an RLC circuit forming one end of a mechanical harmonic oscillator is investigated. We show that, in some configurations, the coherent interaction of the wave with both the mechanical oscillator and the RLC circuit gives rise to a mechanical quality factor increase of the electromagnetic signal. When this system is used as an amplifier of gravitational periodic signals in the frequency range 50-1000 Hz, at ultracryogenic temperatures and for sufficiently long integration times (up to 4 months), a sensitivity of 10^(-24)-10^(-27) on the amplitude of the metric could be achieved when thermal noise, shot noise and amplifier back--action are considered.
Unravelling the influence of water depth and wave energy on the facies diversity of shelf carbonates
Purkis, Sam
Unravelling the influence of water depth and wave energy on the facies diversity of shelf their production is tied to light and wave energy, carbonate sediments are most effectively produced in shallow energy regime to be reliable indicators of facies type when considered in isolation. Consid- ered
THE INFLUENCE OF WAVES ON THE OFFSHORE WIND Bernhard Lange, Jrgen Hjstrup*
Heinemann, Detlev
THE INFLUENCE OF WAVES ON THE OFFSHORE WIND RESOURCE Bernhard Lange, Jørgen Højstrup* Risø National and waves and thus in air-sea interaction in general. For predicting the offshore wind climate'8&7,21 The favourable wind resource at offshore compared to land sites is caused by the very low surface roughness
Alexandre Nicolas; Francesco Puosi; Hideyuki Mizuno; Jean-Louis Barrat
2015-03-05T23:59:59.000Z
Shear transformations (i.e., localised rearrangements of particles resulting in the shear deformation of a small region of the sample) are the building blocks of mesoscale models for the flow of disordered solids. In order to compute the time-dependent response of the solid material to such a shear transformation, with a proper account of elastic heterogeneity and shear wave propagation, we propose and implement a very simple Finite-Element (FE) -based method. Molecular Dynamics (MD) simulations of a binary Lennard-Jones glass are used as a benchmark for comparison, and information about the microscopic viscosity and the local elastic constants is directly extracted from the MD system and used as input in FE. We find very good agreement between FE and MD regarding the temporal evolution of the disorder-averaged displacement field induced by a shear transformation, which turns out to coincide with the response of a uniform elastic medium. However, fluctuations are relatively large, and their magnitude is satisfactorily captured by the FE simulations of an elastically heterogeneous system. Besides, accounting for elastic anisotropy on the mesoscale is not crucial in this respect. The proposed method thus paves the way for models of the rheology of amorphous solids which are both computationally efficient and realistic, in that structural disorder and inertial effects are accounted for.
The Influence of Basalt Layers on Seismic Wave Propagation
Hanssen, Peter
are to examine the effects of basalts on seismic wave propagation and the concequent implications for imaging sedimentary structures beneath them. From studies of basalt propertiesand borehole data in connection with foreward modelling and real data, I show...
Influence of Nonlinear Irregular Waves on the Fatigue Loads of an Offshore Wind Turbine
Papalambros, Panos
it acts as a bottleneck to the realization of offshore wind farms that can compete with traditional energy sources [3]. Currently, offshore wind farms are typically sited in coastal areas with water depths aroundInfluence of Nonlinear Irregular Waves on the Fatigue Loads of an Offshore Wind Turbine Michiel B
A. V. Sedelnikov; M. I Kazarina
2010-07-23T23:59:59.000Z
At this project considers the problem of analysis temperature deformation of elastic elements of the spacecraft. Spacecraft periodically appears in the earth's shadow on the sunny side when moving from the orbit. Abruptly changing the temperature field of large elastic elements can affect the dynamic characteristics of the spacecraft. This is important when dealing with the implementation of the gravity-sensitive processes on board.
A model for enhanced fluid percolation in porous media by application of low-frequency elastic waves
Beresnev, Igor
, primarily in connection with the appli- cations to enhanced oil recovery (EOR) and remediation of nonaqueousA model for enhanced fluid percolation in porous media by application of low-frequency elastic can significantly enhance transport of nonaqueous phase liquids (NAPLs) in porous media. Our analyses
Influence of the backward propagating waves on the threshold in planar nematic liquid crystal films
Dmitry O. Krimer; Andrey E. Miroshnichenko; Etienne Brasselet
2010-10-19T23:59:59.000Z
We analyze theoretically the influence of backward propagating waves on the primary threshold when a linearly polarized light impinges at normal incidence on a planarly aligned nematic liquid crystal films. We show, that the primary threshold, as a function of the phase delay induced by the nematic layer, exhibits oscillations. The amplitude of oscillations depends strongly on the drop of the refractivity indices of the nematic and outer media at the boundaries.
Naoto Yokoyama; Masanori Takaoka
2014-12-09T23:59:59.000Z
A single-wavenumber representation of nonlinear energy spectrum, i.e., stretching energy spectrum is found in elastic-wave turbulence governed by the F\\"oppl-von K\\'arm\\'an (FvK) equation. The representation enables energy decomposition analysis in the wavenumber space, and analytical expressions of detailed energy budget in the nonlinear interactions are obtained for the first time in wave turbulence systems. We numerically solved the FvK equation and observed the following facts. Kinetic and bending energies are comparable with each other at large wavenumbers as the weak turbulence theory suggests. On the other hand, the stretching energy is larger than the bending energy at small wavenumbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode $a_{\\bm{k}}$ and its companion mode $a_{-\\bm{k}}$ is observed at the small wavenumbers. Energy transfer shows that the energy is input into the wave field through stretching-energy transfer at the small wavenumbers, and dissipated through the quartic part of kinetic-energy transfer at the large wavenumbers. A total-energy flux consistent with the energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.
Edinburgh, University of
of power-law or fractal distribution of scalelengths on transmitted wave elds, and we conclude that frequency characteristics, such as the frequency of the peak attenuation, can be related to spatial size scale inclusions or fractures such as in hydrocarbon reservoirs. Several theories exist
Thermoacoustic Tomography in Elastic Media
Justin Tittelfitz
2011-10-11T23:59:59.000Z
We investigate the problem of recovering the initial displacement f for a solution u of a linear, isotropic, non-homogeneous elastic wave equation, given measurements of u on [0,T] x \\partial \\Omega, where \\Omega\\subset\\R^3 is some bounded domain containing the support of f. For the acoustic wave equation, this problem is known as thermoacoustic tomography (TAT), and has been well-studied; for the elastic wave equation, the situation is somewhat more subtle, and we give sufficient conditions on the Lam\\'e parameters to ensure that recovery is possible.
Pascal, Remy Claude Rene
2012-11-29T23:59:59.000Z
Accurate predictions of the annual energy yield from wave energy converters are essential to the development of the wave industry. The current method based on power matrices uses only a small part of the data available ...
LaCure, Mari Mae
2010-04-29T23:59:59.000Z
Waves is the supporting document to the Master of Fine Arts thesis exhibition of the same title. Exhibited March 7-12 2010 in the Art and Design Gallery at the University of Kansas, Waves was comprised of a series of mixed media drawings...
anisotropic elastic constants: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
under scale factors rescalings. Davi C. Rodrigues 2007-08-08 17 UltrasonicsBaron Propagation of elastic waves in an anisotropic functionally graded hollow cylinder in...
Water-waves as a spatial reversible dynamical system, influence of ...
2004-10-08T23:59:59.000Z
The mathematical study of travelling waves, in the context of two di- mensional ... A normal form analysis shows that in most cases, the dynamics on the center ...
Paris-Sud XI, UniversitÃ© de
and the surrounding soft tissues are attenuating media, which might affect the radiofrequency signals measured systems and media, 43.20.Mv Waveguides, wave propagation in tubes and ducts, 43.20.Px Transient radiation and scattering, 43.40.Rj Radiation from vibrating structures into fluid media, 43.35.Pt Surface waves in solids
Comparison of finite-difference and ray-theory seismograms in the elastic SEG/EAGE Salt Model,
Cerveny, Vlastislav
Comparison of finite-difference and ray-theory seismograms in the elastic SEG/EAGE Salt Model, shot-difference seismograms for a selected shot and two receiver configurations com- puted in the elastic SEG/EAGE Salt Model-waves and converted S-waves in the smoothed elastic SEG/EAGE Salt Model are computed. Keywords Elastic velocity model
Tattersall, Wade [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Chiari, Luca [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia)] [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Machacek, J. R.; Anderson, Emma; Sullivan, James P. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)] [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); White, Ron D. [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia)] [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Brunger, M. J. [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia) [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Buckman, Stephen J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia) [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Garcia, Gustavo [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain)] [Instituto de F?sica Fundamental, Consejo Superior de Investigationes Cient?ficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain); Blanco, Francisco [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)] [Departamento de F?sica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
2014-01-28T23:59:59.000Z
Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.
in the Earth. In the laboratory, the disturbance that induces elastic changes is a low-frequency wave sandstone as a function of the applied low-frequency (LF) axial strain (varied from 10À7 to 10À5 the wave speed is measured as a function of the applied static load. Dynamic acousto-elasticity uses low-frequency
Wang, J.; Zhang, X., E-mail: zhangxm@ecust.edu.cn; Yu, L.; Zhao, X. [East China University of Science and Technology, Department of Physics (China)
2014-12-15T23:59:59.000Z
In tokamaks, fusion generated ? particles may absorb lower hybrid (LH) wave energy, thus reducing the LH current drive efficiency. The absorption coefficient ?{sub ?} of LH waves due to ? particles changing with some typical parameters is calculated in this paper. Results show that ?{sub ?} increases with the parallel refraction index n{sub ?}, while decreases with the frequency of LH waves ? over a wide range. Higher background plasma temperature and toroidal magnetic field will increase the absorption. The absorption coefficient ?{sub ?} increases with n{sub e} when n{sub e} ? 8 × 10{sup 19} m{sup ?3}, while decreases with n{sub e} when n{sub e} becomes larger, and there is a peak value of ?{sub ?} when n{sub e} ? 8 × 10{sup 19} m{sup ?1} for the ITER-like scenario. The influence of spectral broadening in parametric decay instabilities on the absorption coefficient is evaluated. The value of ?{sub ?} with n{sub ?} being 2.5 is almost two times larger than that with n{sub ?} being 2.0 and is even lager in the case of 2.9, which will obviously increase the absorption of the LH power by alpha particles.
Teleconnection Pattern influence on sea wave climate in the Bay of Biscay
Boyer, Edmond
a function of offshore sea state conditions, nearshore winds, and local bathymetry. Therefore, large scale evolution. In the northern Atlantic, swell is created by storm winds that cross the Atlantic following west are one of the major factors of shoreline evolution: they are created either by local winds (wind waves
Propagation of nonlinear waves in waveguides and application to nondestructive stress measurement
Nucera, Claudio
2012-01-01T23:59:59.000Z
of ultrasonic wave propagation to identify defects in investigation of elastic wave propagation in a cylinder. Modeling guided wave propagation with application to the
Lo, W.-C.
2009-01-01T23:59:59.000Z
1988, Bulk elastic wave propagation in partially saturated1986, Compressional wave propagation in liquid and/or gassaturation and seismic-wave propagation, Annu. Rev. Earth
Transversely isotropic elasticity and poroelasticity arising from thin isotropic layers
Berryman, J.G.
1997-07-01T23:59:59.000Z
Since the classic work of Postma [1955] and Backus [1962], much has been learned about elastic constants in vertical transversely isotropic (VTI) media when the anisotropy is due to fine layering of isotropic elastic materials. However, new results are still being discovered. For example, the P-wave anisotropy parameter c{sub 11}/c{sub 33} lies in the range 1/4 {<=} c{sub 11}/c{sub 33} {<=} <{lambda}+2{mu}><1/({lambda}+2{mu})>, when the layers are themselves composed of isotropic elastic materials with Lame constants {lambda} and {mu} and the vertical average of the layers is symbolized by <{center_dot}>. The lower bound corrects a result of Postma. For porous layers, a connected solid frame forms the basis of the elastic behavior of a poroelastic medium in the presence of confining forces, while connected pores permit a percolating fluid (if present) to influence the mechanical response of the system from within. For isotropic and anisotropic poroelastic media, we establish general formulas for the behavior of transversely isotropic poroelasticity arising from laminations of isotropic components. The Backus averaging method is shown to provide elementary means of constructing general formulas. The results for confined fluids are then compared with the more general Gassmann [1951] formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement. Such results are important for applications to oil exploration using AVO (amplitude versus offset) since the presence or absence of a fluid component, as well as the nature of the fluid, is the critical issue and the ways in which the fluid influences seismic reflection data still need to be better understood.
Winey, J. M.; Gupta, Y. M. [Institute for Shock Physics and Department of Physics, Washington State University, Pullman, Washington 99164 (United States)
2014-07-21T23:59:59.000Z
Understanding and modeling the response of hcp metals to high stress impulsive loading is challenging because the lower crystal symmetry, compared to cubic metals, results in a significantly more complex material response. To gain insight into the inelastic deformation of hcp metals subjected to high dynamic stresses, shock wave compression of single crystals provides a useful approach because different inelastic deformation mechanisms can be examined selectively by shock compression along different crystal orientations. As a representative example, we report, here, on wave propagation simulations for beryllium (Be) single crystals shocked along the c-axis, a-axis, and several low-symmetry directions to peak stresses reaching 7?GPa. The simulations utilized a time-dependent, anisotropic material model that incorporated dislocation dynamics, deformation twinning, and shear cracking based descriptions of inelastic deformation. The simulation results showed good overall agreement with measured wave profiles for all the different crystal orientations examined [Pope and Johnson, J. Appl. Phys. 46, 720 (1975)], including features arising from wave mode coupling due to the highly anisotropic inelastic response of Be. This good agreement demonstrates that the measured profiles can be understood in terms of dislocation slip along basal, prismatic, and pyramidal planes, together with deformation twinning along (101{sup ¯}2) planes. Our results show that the response of shocked Be single crystals involves the simultaneous operation of multiple, distinct inelastic deformation mechanisms for all orientations except the c-axis. For shocked c-axis Be, the measured wave profiles do not provide good discrimination between pyramidal slip and other inelastic deformation mechanisms, such as shear cracking. The findings presented here provide insight into the complex inelastic deformation response of shocked Be single crystals and are expected to be useful for other hcp crystals. More broadly, the present work demonstrates the potential of shock wave propagation along low-symmetry directions to examine, and discriminate between, different inelastic deformation mechanisms in crystalline solids.
Beresnev, Igor
of oil production: A review of methods and results lgor A. Beresnev* and Paul A. Johnson ABSTRACT from earthquakes and cultural noise may alter water and oil production. In some cases wave excitation of the mechanisms are necessary. INTRODUCTION Declining production in oil recovery operations is of major concern
Environmental Influences on the LIGO Gravitational Wave Detectors during the 6th Science Run
Effler, A; Frolov, V V; Gonzalez, G; Kawabe, K; Smith, J R; Birch, J; McCarthy, R
2014-01-01T23:59:59.000Z
We describe the influence of environmental noise on LIGO detectors in the sixth science run (S6), from July 2009 to October 2010. We show results from experimental investigations testing the coupling level and mechanisms for acoustic, electromagnetic/magnetic and seismic noise to the instruments. We argument the sensors' importance for vetoes of false positive detections, report estimates of the noise sources' contributions to the detector background, and discuss the ways in which environmental coupling should be reduced in the LIGO upgrade, Advanced LIGO.
2007-01-01T23:59:59.000Z
Zhou, G. S. ?1980?. “Wave propagation method of site seismicUse of Exact Solutions of Wave Propagation Problems to Guidesolutions for body wave propagation through an elastic
Seismic waves in rocks with fluids and fractures
Berryman, J.G.
2007-05-14T23:59:59.000Z
Seismic wave propagation through the earth is often stronglyaffected by the presence of fractures. When these fractures are filledwith fluids (oil, gas, water, CO2, etc.), the type and state of the fluid(liquid or gas) can make a large difference in the response of theseismic waves. This paper summarizes recent work on methods ofdeconstructing the effects of fractures, and any fluids within thesefractures, on seismic wave propagation as observed in reflection seismicdata. One method explored here is Thomsen's weak anisotropy approximationfor wave moveout (since fractures often induce elastic anisotropy due tononuniform crack-orientation statistics). Another method makes use ofsome very convenient fracture parameters introduced previously thatpermit a relatively simple deconstruction of the elastic and wavepropagation behavior in terms of a small number of fracture parameters(whenever this is appropriate, as is certainly the case for small crackdensities). Then, the quantitative effects of fluids on thesecrack-influence parameters are shown to be directly related to Skempton scoefficient B of undrained poroelasticity (where B typically ranges from0 to 1). In particular, the rigorous result obtained for the low crackdensity limit is that the crack-influence parameters are multiplied by afactor (1 ? B) for undrained systems. It is also shown how fractureanisotropy affects Rayleigh wave speed, and how measured Rayleigh wavespeeds can be used to infer shear wave speed of the fractured medium.Higher crack density results are also presented by incorporating recentsimulation data on such cracked systems.
The elastic anisotropy of marble
Gebhard, Susan Nash
1982-01-01T23:59:59.000Z
on acoustic anisotropy in marble has been shown to be negligable in four naturally-deformed samples. Compressional-wave velocities in each of the samples were calculated from the single crystal elastic constants of calcite and the orien- tat1ons... thanks to my husband, Fred Tubb, for his patience and support. This research was supported by the National Science Foundation under grant OCN 7817919 and Office of Naval Research contract N-00014- 80-0-0013. To my mother and father, for al1...
Elasticity of hydrous wadsleyite to 12 GPa: Implications for Earth's transition zone
Duffy, Thomas S.
on elasticity of hydrous olivine polymorphs is necessary to model seismic wave speeds for potential hydrousElasticity of hydrous wadsleyite to 12 GPa: Implications for Earth's transition zone Z. Mao,1 S. D regions of the mantle. Here we report single-crystal elastic properties of wadsleyite, b-Mg2SiO4, with 0
Dynamics of structures coupled with elastic media -a review of numerical models and methods
Paris-Sud XI, UniversitÃ© de
), the structure's environment is restricted here to a large and possibly unbounded visco-elastic medium. Under in the field of structure-environment interaction problems, in which the environment is an elastic body and vibration emitted by transportation systems and wave diffraction by obstacles in an elastic medium
E. B. Herbold; V. F. Nesterenko; C. Daraio
2005-12-22T23:59:59.000Z
Strongly nonlinear phononic crystals were assembled from stainless steel spheres. Single solitary waves and splitting of an initial pulse into a train of solitary waves were investigated in different viscous media using motor oil and non-aqueous glycerol to introduce a controlled viscous dissipation. Experimental results indicate that the presence of a viscous fluid dramatically altered the splitting of the initial pulse into a train of solitary waves. Numerical simulations qualitatively describe the observed phenomena only when a dissipative term based on the relative velocity between particles is introduced.
Elastic building blocks for confined sheets
Robert D. Schroll; Eleni Katifori; Benny Davidovitch
2010-12-17T23:59:59.000Z
We study the behavior of thin elastic sheets that are bent and strained under the influence of weak, smooth confinement. We show that the emerging shapes exhibit the coexistence of two types of domains that differ in their characteristic stress distributions and energies, and reflect different constraints. A focused-stress patch is subject to a geometric, piecewise-inextensibility constraint, whereas a diffuse-stress region is characterized by a mechanical constraint - the dominance of a single component of the stress tensor. We discuss the implications of our findings for the analysis of elastic sheets that are subject to various types of forcing.
Sirajuddeen, M. Mohamed Sheik, E-mail: msheiksiraj@bsauniv.ac.in; Banu, I. B. Shameem [Department of Physics, B. S. Abdur Rahman University, Chennai-600 048 (India)
2014-05-15T23:59:59.000Z
Full Potential- Linear Augmented Plane Wave (FP-LAPW) method has been employed to study the electronic, magnetic, elastic and thermal properties of Fe-doped Zirconium nitride. In this work, Fe-atoms were doped into the super cell of ZrN in doping concentrations of 12.5%, 25% and 37.5% to replace Zr atoms. Electronic properties such as band structure and DOS were plotted and compared for the doped compounds. Charge density contours were plotted for all the doped compounds. The non-magnetic ZrN doped in different Fe concentrations were found to be ferromagnetic. Magnetic moments have been calculated and compared. Elastic properties have been studied and compared with electronic properties. Appearance of magnetic ordering and its influence with the elastic properties have been reported. Impact of 3d states of Fe in DOS plot on the elastic nature of the compounds has been highlighted. Thermal properties such as Debye temperature and molar heat capacities at low temperature have been determined. Debye temperature is found to decrease with higher doping concentrations. Molar heat capacities are found to increase with higher concentrations of Fe atoms.
acoustic wave velocity: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
the offered analytical method the determinant relation for a phase velocities of elastic waves for an arbitrary propagation directions in a piezoelectric crystal are received. The...
Time reversed wave propagation experiments in chaotic micro-structured cavities
Sprik, Rudolf
Time reversed wave propagation experiments in chaotic micro-structured cavities Rudolf Sprik a Chimie Industrielles, Paris, France Abstract The elastic wave propagation in strongly scattering solid; Elastic wave propagation The propagation of waves through systems with strong scatterers is ubiquitous
Direct and Inverse Problems for Wave Propagation in Random Media February 29, 2000
Asch, Mark
vector and #27;(z) is the dissipation. The local acoustic sound speed is given by c(z) = s K(z) #26;(z Abstract The propagation of waves (acoustic, elastic, electromagnetic) in randomly layered media is highly that our work on the acoustic wave equation can be generalized to elastic waves and electromagnetic waves
Sewell, T. D. (Thomas D.); Bedrov, D. (Dmitry); Menikoff, Ralph; Smith, G. D. (Grant D.)
2001-01-01T23:59:59.000Z
Atomistic molecular dynamics simulations have been used to calculate isothermal elastic properties for {beta}-, {alpha}-, and {delta}-HMX. The complete elastic tensor for each polymorph was determined at room temperature and pressure via analysis of microscopic strain fluctuations using formalism due to Rahman and Parrinello [J. Chem. Phys. 76,2662 (1982)]. Additionally, the isothermal compression curve was computed for {beta}-HMX for 0 {le} p {le} 10.6 GPa; the bulk modulus K and its pressure derivative K{prime} were obtained from two fitting forms employed previously in experimental studies of the {beta}-HMX equation of state. Overall, the results indicate good agreement between the bulk modulus predicted from the measured and calculated compression curves. The bulk modulus determined directly from the elastic tensor of {beta}-HMX is in significant disagreement with the compression curve-based results. The explanation for this discrepancy is an area of current research.
Elastic parabolic equation solutions for underwater acoustic problems using seismic sources
. Franka) Department of Mathematics, Marist College, 3399 North Road, Poughkeepsie, New York 12601 Robert I that it may be necessary to account for elastic bottom interactions. In order to study energy conversion elastic energy is converted to acoustic energy at the ocean-bottom interface. These waves enter
Torres-VerdÃn, Carlos
Solution of coupled acousticÂelastic wave propagation problems with anelastic attenuation using Keywords: Borehole acoustic logging Wave propagation Linear elasticity Coupled problems Hp-adaptive finite to various poroelasticity theories. Simulations of sonic tools. Numerical modeling of the wave prop- agation
Acoustic excitations and elastic heterogeneities in disordered solids
Hideyuki Mizuno; Stefano Mossa; Jean-Louis Barrat
2014-03-26T23:59:59.000Z
In the recent years, much attention has been devoted to the inhomogeneous nature of the mechanical response at the nano-scale in disordered solids. Clearly, the elastic heterogeneities that have been characterized in this context are expected to strongly impact the nature of the sound waves which, in contrast to the case of perfect crystals, cannot be completely rationalized in terms of phonons. Building on previous work on a toy model showing an amorphisation transition [Mizuno H, Mossa S, Barrat JL (2013) EPL {\\bf 104}:56001], we investigate the relationship between sound waves and elastic heterogeneities in a unified framework, by continuously interpolating from the perfect crystal, through increasingly defective phases, to fully developed glasses. We provide strong evidence of a direct correlation between sound waves features and the extent of the heterogeneous mechanical response at the nano-scale.
1.138J / 2.062J Wave Propagation, Fall 2000
Mei, Chiang C.
Linearized theory of wave phenomena in applied mechanics. Examples are chosen from elasticity, acoustics, geophysics, hydrodynamics and other subjects. Basic concepts. One dimensional examples. Characteristics, dispersion ...
Lunt, A. J. G., E-mail: alexander.lunt@eng.ox.ac.uk; Xie, M. Y.; Baimpas, N.; Korsunsky, A. M. [Department of Engineering Science, University of Oxford, Parks Road, Oxford OX1 3PJ (United Kingdom); Zhang, S. Y.; Kabra, S.; Kelleher, J. [ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell, Oxford OX11 0QX (United Kingdom); Neo, T. K. [Specialist Dental Group, Mount Elizabeth Orchard, 3 Mount Elizabeth, #08-03/08-08/08-10, Singapore 228510 (Singapore)
2014-08-07T23:59:59.000Z
Yttria Stabilised Zirconia (YSZ) is a tough, phase-transforming ceramic that finds use in a wide range of commercial applications from dental prostheses to thermal barrier coatings. Micromechanical modelling of phase transformation can deliver reliable predictions in terms of the influence of temperature and stress. However, models must rely on the accurate knowledge of single crystal elastic stiffness constants. Some techniques for elastic stiffness determination are well-established. The most popular of these involve exploiting frequency shifts and phase velocities of acoustic waves. However, the application of these techniques to YSZ can be problematic due to the micro-twinning observed in larger crystals. Here, we propose an alternative approach based on selective elastic strain sampling (e.g., by diffraction) of grain ensembles sharing certain orientation, and the prediction of the same quantities by polycrystalline modelling, for example, the Reuss or Voigt average. The inverse problem arises consisting of adjusting the single crystal stiffness matrix to match the polycrystal predictions to observations. In the present model-matching study, we sought to determine the single crystal stiffness matrix of tetragonal YSZ using the results of time-of-flight neutron diffraction obtained from an in situ compression experiment and Finite Element modelling of the deformation of polycrystalline tetragonal YSZ. The best match between the model predictions and observations was obtained for the optimized stiffness values of C11?=?451, C33?=?302, C44?=?39, C66?=?82, C12?=?240, and C13?=?50 (units: GPa). Considering the significant amount of scatter in the published literature data, our result appears reasonably consistent.
Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.
1988-12-01T23:59:59.000Z
Elastic emission polishing, also called elastic emission machining (EEM), is a process where a stream of abrasive slurry is used to remove material from a substrate and produce damage free surfaces with controlled surface form. It is a noncontacting method utilizing a thick elasto-hydrodynamic film formed between a soft rotating ball and the workpiece to control the flow of the abrasive. An apparatus was built in the Center, which consists of a stationary spindle, a two-axis table for the workpiece, and a pump to circulate the working fluid. The process is controlled by a programmable computer numerical controller (CNC), which presently can operate the spindle speed and movement of the workpiece in one axis only. This apparatus has been used to determine material removal rates on different material samples as a function of time, utilizing zirconium oxide (ZrO{sub 2}) particles suspended in distilled water as the working fluid. By continuing a study of removal rates the process should become predictable, and thus create a new, effective, yet simple tool for ultra-precision mechanical machining of surfaces.
Mazur, V. A., E-mail: ninesmartcats@yahoo.com; Chuiko, D. A. [Russian Academy of Sciences, Institute of Solar-Terrestrial Physics, Siberian Branch (Russian Federation)
2013-12-15T23:59:59.000Z
The coefficient of reflection of a fast magnetosonic wave incident on the magnetosphere from the solar wind is studied analytically in the framework of a plane-stratified model of the medium with allowance for the transverse inhomogeneity of the magnetosphere and a jump of the plasma parameters at the magnetopause. Three factors decisively affecting the properties of reflection are taken into account: the shear flow of the solar wind plasma relative to the magnetosphere; the presence of a magnetospheric magnetohydrodynamic waveguide caused by the transverse plasma inhomogeneity; and the presence of an Alfvén resonance deep in the magnetosphere, where the oscillation energy dissipates. If the solar wind velocity exceeds the wave phase velocity along the magnetopause, then the wave energy in the solar wind is negative and such a wave experiences overreflection. In the opposite case, the wave energy is positive and the wave is reflected only partially. The wave reflection has a pronounced resonant character: the reflection coefficient has deep narrow minima or high narrow maxima at the eigenfrequencies of the magnetospheric waveguide. For other frequencies, the reflection coefficient only slightly differs from unity. The wave energy influx into the magnetosphere is positive for waves with both positive and negative energies. For waves with a negative energy, this is a consequence of their overreflection, because the flux of negative energy carried away by the reflected wave exceeds the incident flux of negative energy.
Characteristics of sound propagation in shallow water over an elastic seabed with a thin cap over a lay- ered elastic seabed with a shear wave speed comparable to but lower than the water-column sound speed. A theoretical analysis and numerical modeling show that, in such environments, low attenua
Weijgaert, Rien van de
;14/03/2014 6 H L H L L Phase & Group Velocity #12;14/03/2014 7 Doppler Effect #12;14/03/2014 8 Shock Waves #12;14/03/2014 14 Supernova Remnant Cassiopeia A Supernova blast waves #12;14/03/2014 15 Tycho's Remnant (SN 1572AD A SNR flythrough Theory of Supernova Blast Waves Supernovae: Type Ia Subsonic deflagration wave turning
Relativistic elasticity of rigid rods and strings
Jose Natario
2014-09-30T23:59:59.000Z
We show that the equation of motion for a rigid one-dimensional elastic body (i.e. a rod or string whose speed of sound is equal to the speed of light) in a two-dimensional spacetime is simply the wave equation. We then solve this equation in a few simple examples: a rigid rod colliding with an unmovable wall, a rigid rod being pushed by a constant force, a rigid string whose endpoints are simultaneously set in motion (seen as a special case of Bell's spaceships paradox), and a radial rigid string that has partially crossed the event horizon of a Schwarzschild black hole while still being held from the outside.
Stability of elastic grid shells
Mesnil, Romain, M. Eng. Massachusetts Institute of Technology
2013-01-01T23:59:59.000Z
The elastic grid shell is a solution that combines double curvature and ease of mounting. This structural system, based on the deformation of an initially at grid without shear stiffness was invented more than fifty years ...
Theory of compressional and shear waves in fluidlike marine Michael J. Buckinghama)
Buckingham, Michael
possesses no skeletal frame, implying that the elastic rigidity modulus of the material is zero. A theory, and is thus a genuine wave equation, even though the sediment shows no elastic rigidity. In effect, the medium to yield expressions relating the compressional and shear wave speeds to the grain size, the porosity
WAVE SPEEDS FOR AN ELASTOPLASTIC MODEL FOR TWODIMENSIONAL DEFORMATIONS WITH A NONASSOCIATIVE FLOW of variables, the character istic speeds of plane wave solutions of the system are computed. For both plastic and elastic deformations, there are two nonzero wave speeds, referred to as fast and slow waves. It is shown
Thermal Fluctuations and Rubber Elasticity
Xiangjun Xing; Paul M. Goldbart; Leo Radzihovsky
2006-09-21T23:59:59.000Z
The effects of thermal elastic fluctuations in rubber materials are examined. It is shown that, due to an interplay with the incompressibility constraint, these fluctuations qualitatively modify the large-deformation stress-strain relation, compared to that of classical rubber elasticity. To leading order, this mechanism provides a simple and generic explanation for the peak structure of Mooney-Rivlin stress-strain relation, and shows a good agreement with experiments. It also leads to the prediction of a phonon correlation function that depends on the external deformation.
Heat transfer between elastic solids with randomly rough surfaces
B. N. J. Persson; B. Lorenz; A. I. Volokitin
2009-08-27T23:59:59.000Z
We study the heat transfer between elastic solids with randomly rough surfaces. We include both the heat transfer from the area of real contact, and the heat transfer between the surfaces in the noncontact regions. We apply a recently developed contact mechanics theory, which accounts for the hierarchical nature of the contact between solids with roughness on many different length scales. For elastic contact, at the highest (atomic) resolution the area of real contact typically consists of atomic (nanometer) sized regions, and we discuss the implications of this for the heat transfer. For solids with very smooth surfaces, as is typical in many modern engineering applications, the interfacial separation in the non-contact regions will be very small, and for this case we show the importance of the radiative heat transfer associated with the evanescent electromagnetic waves which exist outside of all bodies.
Hadron mass scaling near the s-wave threshold
Tetsuo Hyodo
2014-12-02T23:59:59.000Z
The influence of a two-hadron threshold is studied for the hadron mass scaling with respect to some quantum chromodynamics parameters. A quantum mechanical model is introduced to describe the system with a one-body bare state coupled with a single elastic two-body scattering. The general behavior of the energy of the bound and resonance state near the two-body threshold for a local potential is derived from the expansion of the Jost function around the threshold. It is shown that the same scaling holds for the nonlocal potential induced by the coupling to a bare state. In p or higher partial waves, the scaling law of the stable bound state continues across the threshold describing the real part of the resonance energy. In contrast, the leading contribution of the scaling is forbidden by the nonperturbative dynamics near the s-wave threshold. As a consequence, the bound state energy is not continuously connected to the real part of the resonance energy. This universal behavior originates in the vanishing of the field renormalization constant of the zero-energy resonance in the s wave. A proof is given for the vanishing of the field renormalization constant, together with a detailed discussion.
OFC/NFOEC '12 Summary --Elastic Networks
California at Davis, University of
DWDMNetworks regarding CAPEX and Power Consumption Axel Klekamp ALU Traffic Engineering and Network Planning consumption and CAPEX for MLR and Elastic Networks. No. of transponders and fibers used is less in elastic
Nonlinear Hysteretic Torsional Waves
J. Cabaret; P. Béquin; G. Theocharis; V. Andreev; V. E. Gusev; V. Tournat
2015-01-09T23:59:59.000Z
We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities, and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other type of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short term memory as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control devices such as strong amplitude-dependent filters.
Nonlinear Hysteretic Torsional Waves
Cabaret, J; Theocharis, G; Andreev, V; Gusev, V E; Tournat, V
2015-01-01T23:59:59.000Z
We theoretically study and experimentally report the propagation of nonlinear hysteretic torsional pulses in a vertical granular chain made of cm-scale, self-hanged magnetic beads. As predicted by contact mechanics, the torsional coupling between two beads is found nonlinear hysteretic. This results in a nonlinear pulse distortion essentially different from the distortion predicted by classical nonlinearities, and in a complex dynamic response depending on the history of the wave particle angular velocity. Both are consistent with the predictions of purely hysteretic nonlinear elasticity and the Preisach-Mayergoyz hysteresis model, providing the opportunity to study the phenomenon of nonlinear dynamic hysteresis in the absence of other type of material nonlinearities. The proposed configuration reveals a plethora of interesting phenomena including giant amplitude-dependent attenuation, short term memory as well as dispersive properties. Thus, it could find interesting applications in nonlinear wave control de...
Spherical Wave Propagation in a Nonlinear Elastic Medium Valeri Korneev
Korneev, Valeri A.
a quantitative part nor data and were abandoned until now. Currently, there is a renewed interest to nonlinear properties of seismic fields and hydrocarbon reservoir characteristics (Zhukov et al.,2008
The interior penalty discontinuous Galerkin method for elastic wave ...
Ambika p PrasadTECHBOOKS
2008-09-16T23:59:59.000Z
results that demand further research. ..... Building Blocks for arbitrary high order ... tool to simulate the seismic response of 2-D and 3-D geological structures,.
Erba, A., E-mail: alessandro.erba@unito.it; Mahmoud, A.; Dovesi, R. [Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino (Italy)] [Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino (Italy); Belmonte, D. [DISTAV, Università di Genova, Corso Europa 26, 16132 Genoa (Italy)] [DISTAV, Università di Genova, Corso Europa 26, 16132 Genoa (Italy)
2014-03-28T23:59:59.000Z
A computational strategy is devised for the accurate ab initio simulation of elastic properties of crystalline materials under pressure. The proposed scheme, based on the evaluation of the analytical stress tensor and on the automated computation of pressure-dependent elastic stiffness constants, is implemented in the CRYSTAL solid state quantum-chemical program. Elastic constants and related properties (bulk, shear and Young moduli, directional seismic wave velocities, elastic anisotropy index, Poisson's ratio, etc.) can be computed for crystals of any space group of symmetry. We apply such a technique to the study of high-pressure elastic properties of three silicate garnet end-members (namely, pyrope, grossular, and andradite) which are of great geophysical interest, being among the most important rock-forming minerals. The reliability of this theoretical approach is proved by comparing with available experimental measurements. The description of high-pressure properties provided by several equations of state is also critically discussed.
Experimental investigation of a horizontal flexible-membrane wave barrier
Choi, Hae-Jin
1997-01-01T23:59:59.000Z
A series of experiments is conducted in a two-dimensional glass-walled wave tank to confirm numerical solutions based on two-dimensional linear hydro-elastic theory for a horizontal flexible-membrane wave barrier. The model test is performed by a...
Liu, Y.M.; Mitchell, T.E. [Los Alamos National Lab., NM (United States); Wadley, H.N.G. [Virginia Univ., Charlottesville, VA (United States). Dept. of Materials Science and Engineering
1996-11-01T23:59:59.000Z
Mechanical properties of unidirectional Nicalon SiC fiber reinforced Ca aluminosilicate (CAS/SiC) and Mg aluminosilicate (MAS/SiC) glass-ceramic composites were investigated by tensile testing and nondestructive laser-ultrasound technique. The Ba-stuffed MAS was either undoped or doped with 5% borosilicate glass. Degradation of elastic stiffness constant C{sub 11} in transverse direction due to interface damage was monitored in situ by measuring the laser- generated ultrasound wave velocity. The three composite materials show different characteristics of macroscopic deformation behavior, which is correlated strongly to interface degradation. A stronger reduction trend of the elastic constant C{sub 11} is associated with a larger degree of inelastic deformation. The fracture surfaces also reveal the close relation between fiber pullout length and interfacial characteristics. Interfaces of these composites were studied by TEM; their influence on inhibiting and deflecting matrix cracks is discussed.
Elastic Hadron Scattering on Li Isotopes at Intermediate Energies
Zhusupov, M.A.; Imambekov, O. [Institute of Experimental and Theoretical Physics, Kazakh State University, ul. Timiryazeva 46, Almaty, 480121 (Kazakhstan); Ibraeva, E.T. [Institute of Nuclear Physics, National Nuclear Center of the Republic of Kazakhstan, Almaty, 480082 (Kazakhstan)
2005-01-01T23:59:59.000Z
The elastic scattering of hadrons (protons, charged pions, and positively charged kaons) on {sup 6,7,8}Li nuclei is analyzed on the basis of Glauber-Sitenko diffraction theory. A few nuclear-wave-function versions found within two- and three-particle potential cluster models are used in the calculations. It is shown that the application of these wave functions in diffraction theory makes it possible to describe adequately the experimental differential cross sections and analyzing powers in hadron scattering at intermediate energies. In this study, particular attention is given to a comparison of the scattering of different particles on the same target nucleus, as well as to a comparison of scattering of particles of the same sort on different target nuclei.
Relativistic models for quasi-elastic neutrino scattering
M. C. Martinez; P. Lava; N. Jachowicz; J. Ryckebusch; K. Vantournhout; J. M. Udias
2006-02-17T23:59:59.000Z
We present quasi-elastic neutrino-nucleus cross sections in the energy range from 150 MeV up to 5 GeV for the target nuclei 12C and 56Fe. A relativistic description of the nuclear dynamics and the neutrino-nucleus coupling is adopted. For the treatment of final-state interactions (FSI) we rely on two frameworks succesfully applied to exclusive electron-nucleus scattering: a relativistic optical potential and a relativistic multiple-scattering Glauber approximation. At lower energies, the optical-potential approach is considered to be the optimum choice, whereas at high energies a Glauber approach is more natural. Comparing the results of both calculations, it is found that the Glauber approach yields valid results down to the remarkably small nucleon kinetic energies of 200 MeV. We argue that the nuclear transparencies extracted from A(e,e'p) measurements can be used to obtain realistic estimates of the effect of FSI mechanisms on quasi-elastic neutrino-nucleus cross sections. We present two independent relativistic plane-wave impulse approximation (RPWIA) calculations of quasi-elastic neutrino-nucleus cross sections. They agree at the percent level, showing the reliability of the numerical techniques adopted and providing benchmark RPWIA results.
Active Sensor Wave Propagation Health Monitoring of Beam and Plate Structures
Giurgiutiu, Victor
1 Active Sensor Wave Propagation Health Monitoring of Beam and Plate Structures Victor Giurgiutiu, Jingjing Bao, Wei Zhao University of South Carolina ABSTRACT Active sensor wave propagation technique is a relatively new method for in-situ nondestructive evaluation (NDE). Elastic waves propagating in material
Determination of Properties of Composite Materials from the Lamb Wave Propagation
Kreinovich, Vladik
Determination of Properties of Composite Materials from the Lamb Wave Propagation: Probabilistic the Lamb waves propagate. Their propagation is de- termined by the dynamic elastic constants Â£Â¥Â¤Â¦Â¨Â§ , so we the ultrasound waves propagate in this composite material, and to reconstruct the values Â£ Â¤Â¦Â§ from the results
Theory of compressional and transverse wave propagation in consolidated porous media
Buckingham, Michael
sediments. The consolidated material is treated as an elastic medium which exhibits a specific form waves, from which expressions for the wave speeds and attenuations are established. In both cases of attenuation in sandstones, limestones, and shales; the wave speeds show weak logarithmic dispersion
Andrey Beresnyak; Alex Lazarian
2008-05-06T23:59:59.000Z
We present a model for nonlinear decay of the weak wave in three-dimensional incompressible magnetohydrodynamic (MHD) turbulence. We show that the decay rate is different for parallel and perpendicular waves. We provide a general formula for arbitrarily directed waves and discuss particular limiting cases known in the literature. We test our predictions with direct numerical simulations of wave decay in three-dimensional MHD turbulence, and discuss the influence of turbulent damping on the development of linear instabilities in the interstellar medium and on other important astrophysical processes.
Section 12: Waves and acoustics 1 Section 12: Waves and acoustics
Kohlenbach, Ulrich
Highly Porous Media Abstract 13:50 Â 14:10: Hoffmann, N.P., Chabchoub, A. (TU Hamburg-Harburg): Experiments on Peregrine soliton type deep water gravity waves Abstract 14:10 Â 14:30: Thomas MÃ¼llner (TU Wien): Acoustical performance of concreted wood fiber materials Abstract S12.4: Elastic Waves Wed, 16:00Â18:00 Chair
ELASTIC AND INELASTIC Y PRODUCTION BY MUONS
Loken, S.C.
2010-01-01T23:59:59.000Z
U.S. Department of Energy under Contract No. W-7405-ENG-48.under Contract No. W-7405-ENG-48. Ui-u ELASTIC AND INELASTIC
Elasticity driven self-organization of polarons
Maniadis, Panagiotis [Los Alamos National Laboratory; Lookman, Turab [Los Alamos National Laboratory; Bishop, Alan R [Los Alamos National Laboratory
2008-01-01T23:59:59.000Z
We use a strain description to couple long-range elastic fields adiabatically to electronic density to describe the behavior of a quantum particle in an elastic medium. We show that in this generalization of the Holstein polaron problem, a bound polaronic state results with strong long-range angular dependence in the elastic fields, but a localized electronic core. The deformation of the elastic fields creates an anisotropic, indirect interaction between polarons extending to large distances. For a given density of polarons, this interaction favors the formation of strings of polarons in preferred directions.
Thermo-optical modulation of ultrasonic surface waves for NDE Zhongyu Yan, Peter B. Nagy *
Nagy, Peter B.
Thermo-optical modulation of ultrasonic surface waves for NDE Zhongyu Yan, Peter B. Nagy 45221-0070, USA Abstract The well-known thermo-elastic effect of laser irradiation can be exploited specimens can be readily de- tected by exploiting this optically induced thermo-elastic modulation during
Transforming Wave Propagation in Layered Media via Instability-Induced Interfacial Wrinkling
Rudykh, Stephan
The ability to control wave propagation in highly deformable layered media with elastic instability-induced wrinkling of interfacial layers is presented. The onset of a wrinkling instability in initially straight interfacial ...
1.138J / 2.062J / 18.376J Wave Propagation, Fall 2004
Akylas, Triantaphyllos R.
This course discusses the Linearized theory of wave phenomena in applied mechanics. Examples are chosen from elasticity, acoustics, geophysics, hydrodynamics and other subjects. The topics include: basic concepts, one ...
Aidun, J.B.; Addessio, F.L.
1995-11-01T23:59:59.000Z
The theoretical basis of the homogenization technique developed by Aboudi is presented and assessed. Given the constitutive relations of the constituents, this technique provides an equivalent, homogeneous, constitutive model of unidirectional, continuous-fiber-reinforced composites. The expressions that comprise the first-order version of the technique are given special attention as this treatment has considerable practical value. Nonlinear elasticity effects are added to it. This extension increases the accuracy of numerical simulations of high strain-rate loadings. It is particularly important for any dynamic loading in which shock waves might be produced, including crash safety, armor, and munitions applications. Examples illustrate that elastic nonlinearity can make substantial contributions at strains of only a few per cent. These contributions are greatest during post-yield inelastic deformation. The micromechanics-based homogenization technique is shown to facilitate use of an efficient approximate treatment of elastic nonlinearity in composites with isotropic matrix materials.
Francine Luppé; Jean-Marc Conoir; Andrew N. Norris
2011-10-06T23:59:59.000Z
The dispersion relation is derived for the coherent waves in fluid or elastic media supporting viscous and thermal effects and containing randomly distributed spherical scatterers. The formula obtained is the generalization of Lloyd and Berry's [Proc. Phys. Soc. Lond. 91, 678-688, 1067], the latter being limited to fluid host media, and it is the three-dimensional counterpart of that derived by Conoir and Norris [Wave Motion 47, 183-197, 2010] for cylindrical scatterers in an elastic host medium.
Nucleon and $?$ elastic and transition form factors
Jorge Segovia; Ian C. Cloet; Craig D. Roberts; Sebastian M. Schmidt
2014-09-03T23:59:59.000Z
We compute nucleon and Delta elastic and transition form factors, and compare predictions made using a framework built upon a Faddeev equation kernel and interaction vertices that possess QCD-like momentum dependence with results obtained using a vector-vector contact-interaction. The comparison emphasises that experiment is sensitive to the momentum dependence of the running couplings and masses in the strong interaction sector of the Standard Model and highlights that the key to describing hadron properties is a veracious expression of dynamical chiral symmetry breaking in the bound-state problem. Amongst the results we describe, the following are of particular interest: $G_E^p(Q^2)/G_M^p(Q^2)$ possesses a zero at $Q^2=9.5GeV^2$; any change in the interaction which shifts a zero in the proton ratio to larger $Q^2$ relocates a zero in $G_E^n(Q^2)/G_M^n(Q^2)$ to smaller $Q^2$; and there is likely a value of momentum transfer above which $G_E^n>G_E^p$. Regarding the $\\Delta(1232)$-baryon, we find that, inter alia: the electric monopole form factor exhibits a zero; the electric quadrupole form factor is negative, large in magnitude, and sensitive to the nature and strength of correlations in the $\\Delta(1232)$ Faddeev amplitude; and the magnetic octupole form factor is negative so long as rest-frame P- and D-wave correlations are included. In connection with the N-to-Delta transition, the momentum-dependence of the magnetic transition form factor, $G_M^\\ast$, matches that of $G_M^n$ once the momentum transfer is high enough to pierce the meson-cloud; and the electric quadrupole ratio is a keen measure of diquark and orbital angular momentum correlations.
Estimation of scalar moments from explosion-generated surface waves
Stevens, J.L.
1985-04-01T23:59:59.000Z
Rayleigh waves from underground nuclear explosions are used to estimate scaler moments for 40 Nevada Test Site (NTS) explosions and 18 explosions at the Soviet East Kazakh test site. The Rayleigh wave spectrum is written as a product of functions that depend on the elastic structure of the travel path, the elastic structure of the source region and the Q structure of the path. Results are used to examine the worldwide variability of each factor and the resulting variability of surface wave amplitudes. The path elastic structure and Q structure are found by inversion of Rayleigh wave phase and group velocities and spectral amplitudes. The Green's function derived from this structure is used to estimate the moments of explosions observed along the same path. This procedure produces more consistent amplitude estimates than conventional magnitude measurements. Network scatter in log moment is typically 0.1. In contrast with time-domain amplitudes, the elastic structure of the travel path causes little variability in spectral amplitudes. When the mantle Q is constrained to a value of approximately 100 at depths greater than 120 km, the inversion for Q and moment produces moments that remain constant with distance. Based on the best models available, surface waves from NTS explosions should be larger than surface waves from East Kazakh explosions with the same moment. Estimated scaler moments for the largest East Kazakh explosions since 1976 are smaller than the estimated moments for the largest NTS explosions for the same time period.
Random Parking and Rubber Elasticity Mathew Penrose
Penrose, Mathew
Random Parking and Rubber Elasticity Mathew Penrose (University of Bath) Joint work with Antoine), Imperial January 2013 #12;Rubber Elasticity Let d, n N (e.g. d = n = 3). Suppose D Rd is a bounded domain. D represents a piece of rubber. Let L Rd be a locally finite point process. L D the locations
ROCK ELASTIC PROPERTIES: DEPENDENCE ON MICROSTRUCTURE
ROCK ELASTIC PROPERTIES: DEPENDENCE ON MICROSTRUCTURE James G. Berryman and Patricia A. Berge Lawrence Livermore National Laboratory P. O. Box 808 L202 Livermore, CA 945519900 #12; ROCK ELASTIC PROPERTIES: DEPENDENCE ON MICROSTRUCTURE James G. Berryman and Patricia A. Berge Lawrence Livermore National
Elastic–Plastic Spherical Contact Modeling Including Roughness Effects
Li, L.; Etsion, I.; Talke, F. E.
2010-01-01T23:59:59.000Z
A multilevel model for elastic–plastic contact between ajunction growth of an elastic–plastic spherical contact. J.nite element based elastic–plastic model for the contact of
Wave propagation and instabilities in monolithic and periodically structured elastomeric materials; revised manuscript received 3 October 2008; published 14 November 2008 Wave propagation in elastomeric states can influence wave propagation and hence interpretation of data. In the case of periodically
High elastic modulus polymer electrolytes
Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel
2013-10-22T23:59:59.000Z
A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics.
Two-wave interaction in ideal magnetohydrodynamics
T. V. Zaqarashvili; B. Roberts
2006-02-24T23:59:59.000Z
The weakly nonlinear interaction of sound and linearly polarised Alfv{\\'e}n waves propagating in the same direction along an applied magnetic field is studied. It is found that a sound wave is coupled to the Alfv{\\'e}n wave with double period and wavelength when the sound and Alfv{\\'e}n speeds are equal. The Alfv{\\'e}n wave drives the sound wave through the ponderomotive force, while the sound wave returns energy back to the Alfv{\\'e}n wave through the parametric (swing) influence. As a result, the two waves alternately exchange their energy during propagation. The process of energy exchange is faster for waves with stronger amplitudes. The phenomenon can be of importance in astrophysical plasmas, including the solar atmosphere and solar wind.
Structure of light neutron-rich nuclei and mechanism of elastic proton scattering
Ibraeva, E. T., E-mail: ibr@inp.kz [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Zhusupov, M. A. [Al-Farabi Kazakh National University (Kazakhstan); Imambekov, O. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan)
2011-11-15T23:59:59.000Z
Differential cross sections for elastic p{sup 6}He, p{sup 8}Li, and p{sup 9}Li scattering at two energies of 70 and 700 MeV per nucleon were calculated within the Glauber theory of multiple diffractive scattering. Threeparticle wave functions ({alpha}-n-n for {sup 6}He, {alpha}-t-n for {sup 8}Li, and {sup 7}Li-n-n for {sup 9}Li) were used for realistic potentials of intercluster interactions. The sensitivity of elastic scattering to proton-nucleus interaction and to the structure of nuclei was explored. In particular, the dependence of the differential cross section on the contribution of higher order collisions, on scattering on the core and peripheral nucleons, and on the contribution of small wave-function components and their asymptotic behavior was determined. A comparison with available experimental data and with the results of calculations within different formalisms was performed.
Hydrogen Species Motion in Piezoelectrics: A Quasi-Elastic Neutron...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Species Motion in Piezoelectrics: A Quasi-Elastic Neutron Scattering Study. Hydrogen Species Motion in Piezoelectrics: A Quasi-Elastic Neutron Scattering Study. Abstract: Hydrogen...
Revisit of the relationship between the elastic properties and sound velocities at high pressures
Wang, Chenju; Yan, Xiaozhen [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); Institute of Atomic and Molecular Sciences, Sichuan University, Chengdu 610065 (China); Xiang, Shikai, E-mail: skxiang@caep.ac.cn; Chen, Haiyan [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); Gu, Jianbing; Yu, Yin [National Key Laboratory of Shock Wave and Detonation Physics, Institute of Fluid Physics, PO Box 919-102, Mianyang, Sichuan 621900 (China); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Kuang, Xiaoyu [Institute of Atomic and Molecular Sciences, Sichuan University, Chengdu 610065 (China); International Centre for Materials Physics, Academia Sinica, Shenyang 110016 (China)
2014-09-14T23:59:59.000Z
The second-order elastic constants and stress-strain coefficients are defined, respectively, as the second derivatives of the total energy and the first derivative of the stress with respect to strain. Since the Lagrangian and infinitesimal strain are commonly used in the two definitions above, the second-order elastic constants and stress-strain coefficients are separated into two categories, respectively. In general, any of the four physical quantities is employed to characterize the elastic properties of materials without differentiation. Nevertheless, differences may exist among them at non-zero pressures, especially high pressures. Having explored the confusing issue systemically in the present work, we find that the four quantities are indeed different from each other at high pressures and these differences depend on the initial stress applied on materials. Moreover, the various relations between the four quantities depicting elastic properties of materials and high-pressure sound velocities are also derived from the elastic wave equations. As examples, we calculated the high-pressure sound velocities of cubic tantalum and hexagonal rhenium using these nexus. The excellent agreement of our results with available experimental data suggests the general applicability of the relations.
Molecular elasticity and the geometric phase
Joseph Samuel; Supurna Sinha
2003-01-23T23:59:59.000Z
We present a method for solving the Worm Like Chain (WLC) model for twisting semiflexible polymers to any desired accuracy. We show that the WLC free energy is a periodic function of the applied twist with period 4 pi. We develop an analogy between WLC elasticity and the geometric phase of a spin half system. These analogies are used to predict elastic properties of twist-storing polymers. We graphically display the elastic response of a single molecule to an applied torque. This study is relevant to mechanical properties of biopolymers like DNA.
Intraclass Price Elasticity & Electric Rate Design
Gresham, K. E.
1987-01-01T23:59:59.000Z
Electric rate design relies on cost incurrance for pricing and pricing structures. However, as utilities move into a marketing mode, rate design needs to respond more to customer reactions to pricing changes. Intraclass price elasticities aid rate...
Mechanical behavior of elastic rods under constraint
Miller, James Thomas, Ph. D. Massachusetts Institute of Technology
2014-01-01T23:59:59.000Z
We present the results of an experimental investigation of the mechanics of thin elastic rods under a variety of loading conditions. Four scenarios are explored, with increasing complexity: i) the shape of a naturally ...
Coiling of elastic rods on rigid substrates
Khalid Jawed, Mohammad
We investigate the deployment of a thin elastic rod onto a rigid substrate and study the resulting coiling patterns. In our approach, we combine precision model experiments, scaling analyses, and computer simulations toward ...
Coiling of elastic rods on rigid substrates
Khalid Jawed, Mohammad
2014-01-01T23:59:59.000Z
We investigate the deployment of a thin elastic rod onto a rigid substrate and study the resulting coiling patterns. In our approach, we combine precision model experiments, scaling analyses, and computer simulations towards ...
Continuously-Variable Series-Elastic Actuator
Mooney, Luke M.
Actuator efficiency is an important factor in the design of powered leg prostheses, orthoses, exoskeletons, and legged robots. A continuously-variable series-elastic actuator (CV-SEA) is presented as an efficient actuator ...
Strong coupling effects in near-barrier heavy-ion elastic scattering
N. Keeley; K. W. Kemper; K. Rusek
2014-09-25T23:59:59.000Z
Accurate elastic scattering angular distribution data measured at bombarding energies just above the Coulomb barrier have shapes that can markedly differ from or be the same as the expected classical Fresnel scattering pattern depending on the structure of the projectile, the target or both. Examples are given such as 18O + 184W and 16O + 148,152Sm where the expected rise above Rutherford scattering due to Coulomb-nuclear interference is damped by coupling to the target excited states, and the extreme case of 11Li scattering, where coupling to the 9Li + n + n continuum leads to an elastic scattering shape that cannot be reproduced by any standard optical model parameter set. The recent availability of high quality 6He, 11Li and 11Be data provides further examples of the influence that coupling effects can have on elastic scattering. Conditions for strong projectile-target coupling effects are presented with special emphasis on the importance of the beam-target charge combination being large enough to bring about the strong coupling effects. Several measurements are proposed that can lead to further understanding of strong coupling effects by both inelastic excitation and nucleon transfer on near-barrier elastic scattering. A final note on the anomalous nature of 8B elastic scattering is presented as it possesses a more or less normal Fresnel scattering shape whereas one would a priori not expect this due to the very low breakup threshold of 8B. The special nature of 11Li is presented as it is predicted that no matter how far above the Coulomb barrier the elastic scattering is measured, its shape will not appear as Fresnel like whereas the elastic scattering of all other loosely bound nuclei studied to date should eventually do so as the incident energy is increased, making both 8B and 11Li truly "exotic".
Intraclass Price Elasticity & Electric Rate Design
Gresham, K. E.
INTRACLASS PRICE ELASTICITY &ELECTRIC RATE DESIGN KEVIN E. GRESHAM Senior Research Analyst Houston Lighting & Power Company Houston, Texas ABSTRACT PRICE ELASTICITY Electric ~ate design relies on cost incur rance for pricing and pricing... industries are already affecting electric utilities. Cogeneration is one example of competition which effects electric utilities. Utilities now have a competing source of generation which often causes load and revenue losses. Competition has specifically...
Tsvankin, Ilya
is believed to be common for fractured reservoirs, the dif- ficulties in dealing with nine independent elastic of P-wave trav- eltime inversion and data processing algorithms in or- thorhombic media. INTRODUCTION.g., Sayers, 1994a) that TI (or hexagonal) symmetry ad- equately describes the elastic properties of shales
DNA Twist Elasticity: Mechanics and Thermal Fluctuations
Supurna Sinha; Joseph Samuel
2010-11-30T23:59:59.000Z
The elastic properties of semiflexible polymers are of great importance in biology. There are experiments on biopolymers like double stranded DNA, which twist and stretch single molecules to probe their elastic properties. It is known that thermal fluctuations play an important role in determining molecular elastic properties, but a full theoretical treatment of the problem of twist elasticity of fluctuating ribbons using the simplest worm like chain model (WLC) remains elusive. In this paper, we approach this problem by taking first a mechanical approach and then incorporating thermal effects in a quadratic approximation applying the Gelfand-Yaglom (GY) method for computing fluctuation determinants. Our study interpolates between mechanics and statistical mechanics in a controlled way and shows how profoundly thermal fluctuations affect the elasticity of semiflexible polymers. The new results contained here are: 1) a detailed study of the minimum energy configurations with explicit expressions for their energy and writhe and plots of the extension versus Link for these configurations. 2) a study of fluctuations around the local minima of energy and approximate analytical formulae for the free energy of stretched twisted polymers derived by the Gelfand Yaglom method. We use insights derived from our mechanical approach to suggest calculational schemes that lead to an improved treatment of thermal fluctuations. From the derived formulae, predictions of the WLC model for molecular elasticity can be worked out for comparison against numerical simulations and experiments.
Paul S. Wesson
2012-12-11T23:59:59.000Z
As an example of the unification of gravitation and particle physics, an exact solution of the five-dimensional field equations is studied which describes waves in the classical Einstein vacuum. While the solution is essentially 5D in nature, the waves exist in ordinary 3D space, and may provide a way to test for an extra dimension.
Interaction Dynamics of Singular Wave Fronts
Holm, Darryl D
2013-01-01T23:59:59.000Z
Some of the most impressive singular wave fronts seen in Nature are the transbasin oceanic internal waves, which may be observed from the Space Shuttle as they propagate and interact with each other, for example, in the South China Sea. The characteristic feature of these strongly nonlinear wavefronts is that they reconnect when two of them collide transversely. We derive the EPDiff equation, and use it to model this phenomenon as elastic collisions between singular wave fronts (solitons) whose momentum is distributed along curves moving in the plane. Numerical methods for EPDiff based on compatible differencing algorithms (CDAs) are used for simulating these collisions among curves. The numerical results show the same nonlinear behavior of wavefront reconnections as that observed for internal waves in the South China Sea. We generalize the singular solutions of EPDiff for other applications, in computational anatomy and in imaging science, where the singular wavefronts are evolving image outlines, whose mome...
Under consideration for publication in J. Fluid Mech. 1 Ocean waves and ice sheets
Craster, Richard
; Wadhams & Holt, 1991) to pack ice (Robin, 1963) and even glacial ice tongues (Holdsworth, 1969; Squire etUnder consideration for publication in J. Fluid Mech. 1 Ocean waves and ice sheets By N. J waves incident on icecovered ocean. The ice cover is idealized as a plate of elastic material for which
WAVE-SOLID INTERACTIONS IN SHOCK INDUCED DEFORMATION PROCESSES Paper #1003
Yao, Y. Lawrence
pressure created by the shock wave is above the dynamic yield stress (Hugonoit Elastic Limit, HEL) of metalWAVE-SOLID INTERACTIONS IN SHOCK INDUCED DEFORMATION PROCESSES Paper #1003 Yajun Fan, Youneng Wang 10027, USA Abstract A model was developed for material deformation processes induced by laser generated
Zeng, Chong; Xia, Jianghai; Miller, Richard D.; Tsoflias, Georgios P.
2012-01-01T23:59:59.000Z
Rayleigh waves are generated along the free surface and their propagation can be strongly influenced by surface topography. Modeling of Rayleigh waves in the near surface in the presence of topography is fundamental to the study of surface waves...
Quark Structure of the Nucleon and Angular Asymmetry of Proton-Neutron Hard Elastic Scattering
Carlos G. Granados; Misak M. Sargsian
2009-07-29T23:59:59.000Z
We investigate an asymmetry in the angular distribution of hard elastic proton-neutron scattering with respect to 90deg center of mass scattering angle. We demonstrate that the magnitude of the angular asymmetry is related to the helicity-isospin symmetry of the quark wave function of the nucleon. Our estimate of the asymmetry within the quark-interchange model of hard scattering demonstrates that the quark wave function of a nucleon based on the exact SU(6) symmetry predicts an angular asymmetry opposite to that of experimental observations. On the other hand the quark wave function based on the diquark picture of the nucleon produces an asymmetry consistent with the data. Comparison with the data allowed us to extract the relative sign and the magnitude of the vector and scalar diquark components of the quark wave function of the nucleon. These two quantities are essential in constraining QCD models of a nucleon. Overall, our conclusion is that the angular asymmetry of a hard elastic scattering of baryons provides a new venue in probing quark-gluon structure of baryons and should be considered as an important observable in constraining the theoretical models.
BOUSSINESQ MODELING OF SURFACE WAVES DUE TO UNDERWATER LANDSLIDES
topography, and the equations of motion for the landslide and surface waves are solved simultaneouslyBOUSSINESQ MODELING OF SURFACE WAVES DUE TO UNDERWATER LANDSLIDES DENYS DUTYKH AND HENRIK KALISCH Abstract. Consideration is given to the influence of an underwater landslide on waves at the surface
BOUSSINESQ MODELING OF SURFACE WAVES DUE TO UNDERWATER LANDSLIDES
topography, and the equations of motion for the landslide and surface waves are solved simultaneouslyBOUSSINESQ MODELING OF SURFACE WAVES DUE TO UNDERWATER LANDSLIDES DENYS DUTYKH # AND HENRIK KALISCH Abstract. Consideration is given to the influence of an underwater landslide on waves at the surface
Wave represents displacement Wave represents pressure Source -Sound Waves
Colorado at Boulder, University of
Wave represents displacement Wave represents pressure Source - Sound Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency Wave represents pressure Target - Radio Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency
Optical theorem and elastic nucleon scattering
Milos V. Lokajicek; Vojtech Kundrat
2009-06-22T23:59:59.000Z
In the theoretical analysis of high-energy elastic nucleon scattering one starts commonly from the description based on the validity of optical theorem, which allows to derive the value of total cross section directly from the experimentally measured t-dependence of elastic differential cross section. It may be shown, however, that this theorem has been derived on the basis of one assumption that might be regarded perhaps as acceptable for long-range (e.g., Coulomb) forces but must be denoted as quite unacceptable for finite-range hadron forces. Consequently, the conclusions leading to the increase of total cross section with energy at higher collision energies must be newly analyzed. The necessity of new analysis concerns also the derivation of elastic scattering t-dependence at very low transverse momenta from measured data.
Elasticity of Twist-Bend Nematic Phases
Epifanio G. Virga
2014-04-12T23:59:59.000Z
The ground state of twist-bend nematic liquid crystals is a heliconical molecular arrangement in which the nematic director precesses uniformly about an axis, making a fixed angle with it. Both precession senses are allowed in the ground state of these phases. When one of the two \\emph{helicities} is prescribed, a single helical nematic phase emerges. A quadratic elastic theory is proposed here for each of these phases which features the same elastic constants as the classical theory of the nematic phase, requiring all of them to be positive. To describe the helix axis, it introduces an extra director field which becomes redundant for ordinary nematics. Putting together helical nematics with opposite helicities, we reconstruct a twist-bend nematic, for which the quadratic elastic energies of the two helical variants are combined in a non-convex energy.
Elastic and Proton Dynamics of the DNA
V. L. Golo
2008-03-28T23:59:59.000Z
The subject of this report is the dynamics of elastic system in conjunction with hydrogen bonds of the DNA. We draw attention to the draw-back of the familiar rod model of the DNA, and make a case of constructing models that could accommodate the intrinsic structure of the DNA. In this respect studying the interplay among the elastic system and the protons of the DNA, is of interest, for it could accommodate the inter-strand as well as the tunneling modes of protons. Following this direction, we come to the conclusion that the elastic-proton dynamics may have a bearing on biophysics of the DNA. The phenomenon of point mutations is discussed within this framework.
Amimoto, S.T.; Chang, D.J. [Aerospace Corporation, Los Angeles, CA (United States)
1995-12-31T23:59:59.000Z
Recently picosecond techniques have been used to generate surface acoustic waves (SAW) with wavelengths of a few microns. Previously generation of short SAW wavelengths required a laser pulse duration shorter than the transit time of the acoustic wave as it traverses the spatial pattern produced by the laser and a thermal relaxation time much faster than the acoustic time constant. In this paper we wish to report an investigation using spatially and temporally modulated light beams using long lasers pulses as a means to generate short acoustic wavelengths. Such a method may be useful in measuring the elastic modulus of thin films. The experiment that is being conducted utilizes two laser beams, one at frequency, vo, and the other at a shifted frequency, vo-v{prime}, to form a traveling interference pattern. The method of generating these frequencies will be described. By adjusting the angle between the two laser beams, the surface wave speed of an arbitrary material used for a thin film can be selectively matched. Using a YAG laser at 1064 rim to create the moving gratings, surface acoustic wavelengths of 1-3 microns may be generated in a variety of materials. The penetration depth of the acoustic wave is approximately the wavelength itself, thus, this method is well suited for characterizing thin films. For multiple thin film layers of different materials, SAW can be selectively produced in any layer of interest provided the top layers are transparent enough to allow the laser energy to be deposited on the intended layer. The presence of these modulated surface waves is detected by a He-Ne laser using light scattering. From the measured surface acoustic wave velocity, Poisson`s ratio, and the specimen density, the elastic modulus may be calculated. Measurements in progress will be reported for a variety of materials.
Phenomenological explanation of elastic anomalies in superlattices
Grimsditch, M.; Fullerton, E.E. [Argonne National Lab., IL (United States); Schuller, I.K. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics
1993-06-01T23:59:59.000Z
The experimental fact that measured elastic and structural properties of superlattices are strongly correlated can be understood on the basis of a simple model based on the packing of hard spheres. The model is consistent with features of many models that have been proposed to explain the supermodulus effect; but contrary to previous explanations, it allows predictions for a given pair of constitutents to be made. For an arbitrary pair of elements, it predicts the existence or non-existence of an elastic anomaly, and a rough estimate of its magnitude.
U?ur, ?ule [Central Research and Practice Laboratory (AH?LAB), Ahi Evran University, 40100 K?r?ehir (Turkey); ?yigör, Ahmet [Department of Physics, Faculty of Science, Gazi University, 06500 Ankara (Turkey)
2014-10-06T23:59:59.000Z
The electronic, elastic and dynamical properties of the quaternary alloy FeNiMnAl have been investigated using a pseudopotential plane wave method within the generalized gradient approximation (GGA). We determined the lattice parameters and the bulk modulus B. In addition, the elastic properties such as elastic constans (C{sub 11}, C{sub 12} and C{sub 44}), the shear modulus G, the young modulus E, the poisson's ratio ? and the B/G ratio are also given. The FeNiMnAl Heusler alloy exhibit a ferromagnetic half-metallic behavior with the total magnetic moment of 4.02 ?{sub B}. The phonon dispersion of FeNiMnAl has been performed using the density functional theory and the direct method with 2×2×2 supercell.
Yakov Itin; Friedrich W. Hehl
2014-11-19T23:59:59.000Z
We study properties of the fourth rank elasticity tensor C within linear elasticity theory. First C is irreducibly decomposed under the linear group into a "Cauchy piece" S (with 15 independent components) and a "non-Cauchy piece" A (with 6 independent components). Subsequently, we turn to the physically relevant orthogonal group, thereby using the metric. We find the finer decomposition of S into pieces with 9+5+1 and of A into those with 5+1 independent components. Some reducible decompositions, discussed earlier by numerous authors, are shown to be inconsistent. --- Several physical consequences are discussed. The Cauchy relations are shown to correspond to A=0. Longitudinal and transverse sound waves are basically related by S and A, respectively.
Mechanism of elastic and inelastic proton scattering on a {sup 15}C nucleus in diffraction theory
Ibraeva, E. T., E-mail: ibr@inp.kz [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Zhusupov, M. A. [Al-Farabi Kazakh National University (Kazakhstan); Imambekov, O. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan)
2012-11-15T23:59:59.000Z
The amplitudes for elastic and inelastic proton scattering on the neutron-rich nucleus {sup 15}C (to its J{sup {pi}} = 5/2{sup +} level in the latter case) in inverse kinematics were calculated within Glauber diffraction theory. First- and second-order terms were taken into account in the multiple-scattering operator. The {sup 15}C wave function in the multiparticle shell model was used. This made it possible to calculate not only respective differential cross sections but also the contribution of proton scattering on nucleons occurring in different shells. The differential cross sections for elastic and inelastic scattering were calculated at the energies of 0.2, 0.6, and 1 GeV per nucleon.
Analysis of the DENZ04 low-energy $\\pi^\\pm p$ elastic-scattering data
Matsinos, Evangelos
2012-01-01T23:59:59.000Z
This paper presents the results of an analysis of the DENZ04 low-energy $\\pi^\\pm p$ differential cross sections. We first analysed separately the $\\pi^+ p$ and the $\\pi^- p$ elastic-scattering measurements on the basis of standard low-energy expansions of the s- and p-wave $K$-matrix elements. After the removal of the outliers (eleven degrees of freedom in the initial database), we subjected the truncated $\\pi^\\pm p$ elastic-scattering databases into a common optimisation scheme using the ETH model; the optimisation failed to produce reasonable values for the model parameters. The phase-shift solution, extracted from the model fit to the data, is very odd. The problems we have encountered in the analysis of the DENZ04 data are due to the shape of the angular distributions of their $\\pi^+ p$ differential cross sections.
Energy dissipation in wave propagation in general relativistic plasma
Ajanta Das; S. Chatterjee
2009-11-03T23:59:59.000Z
Based on a recent communication by the present authors the question of energy dissipation in magneto hydrodynamical waves in an inflating background in general relativity is examined. It is found that the expanding background introduces a sort of dragging force on the propagating wave such that unlike the Newtonnian case energy gets dissipated as it progresses. This loss in energy having no special relativistic analogue is, however, not mechanical in nature as in elastic wave. It is also found that the energy loss is model dependent and also depends on the number of dimensions.
THE RESPONSE OF SOLIDS TO ELASTIC/ PLASTIC INDENTATION
Chiang, S.S.
2013-01-01T23:59:59.000Z
OF SOLIDS TO ELASTIC/PLASTIC INDENTATION S.S. Chiang, D.B.134. Table I Normalized Plastic Zone Size (B) and Materialken from the elastic/plastic boundary, surface intersection,
Nonaffine rubber elasticity for stiff polymer networks
C. Heussinger; B. Schaefer; E. Frey
2007-11-26T23:59:59.000Z
We present a theory for the elasticity of cross-linked stiff polymer networks. Stiff polymers, unlike their flexible counterparts, are highly anisotropic elastic objects. Similar to mechanical beams stiff polymers easily deform in bending, while they are much stiffer with respect to tensile forces (``stretching''). Unlike in previous approaches, where network elasticity is derived from the stretching mode, our theory properly accounts for the soft bending response. A self-consistent effective medium approach is used to calculate the macroscopic elastic moduli starting from a microscopic characterization of the deformation field in terms of ``floppy modes'' -- low-energy bending excitations that retain a high degree of non-affinity. The length-scale characterizing the emergent non-affinity is given by the ``fiber length'' $l_f$, defined as the scale over which the polymers remain straight. The calculated scaling properties for the shear modulus are in excellent agreement with the results of recent simulations obtained in two-dimensional model networks. Furthermore, our theory can be applied to rationalize bulk rheological data in reconstituted actin networks.
The elasticity of -helices Seungho Choe
Sun, Sean
The elasticity of -helices Seungho Choe Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218 Sean X. Suna Department of Mechanical Engineering and Whitaker chemical energy into mechanical work. Binding of nucleotides such as ATP generates a local- ized force
the nonlinear dependence of sound propagation speed with pressure, we evidence the anomalous elastic softness show that the propagation of surface sound waves provides insights into the structure of the elastic--and seismic geology [7,8]. In both cases, a surpris- ingly low speed of sound ( $ 50 m=s) was observed
Anisotropic thermo-elasticity in 2D -- Part II: Applications
Jens Wirth
2007-11-15T23:59:59.000Z
In this note we present concrete applications of the general treatment of anisotropic thermo-elasticity developed in Part I.
Wave turbulence served up on a plate
Pablo Cobelli; Philippe Petitjeans; Agnes Maurel; Vincent Pagneux; Nicolas Mordant
2009-10-28T23:59:59.000Z
Wave turbulence in a thin elastic plate is experimentally investigated. By using a Fourier transform profilometry technique, the deformation field of the plate surface is measured simultaneously in time and space. This enables us to compute the wavevector-frequency Fourier ($\\mathbf k, \\omega$) spectrum of the full space-time deformation velocity. In the 3D ($\\mathbf k, \\omega$) space, we show that the energy of the motion is concentrated on a 2D surface that represents a nonlinear dispersion relation. This nonlinear dispersion relation is close to the linear dispersion relation. This validates the usual wavenumber-frequency change of variables used in many experimental studies of wave turbulence. The deviation from the linear dispersion, which increases with the input power of the forcing, is attributed to weak non linear effects. Our technique opens the way for many new extensive quantitative comparisons between theory and experiments of wave turbulence.
Microfabricated bulk wave acoustic bandgap device
Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming leg, Carol
2010-06-08T23:59:59.000Z
A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).
Microfabricated bulk wave acoustic bandgap device
Olsson, Roy H. (Albuquerque, NM); El-Kady, Ihab F. (Albuquerque, NM); McCormick, Frederick (Albuquerque, NM); Fleming, James G. (Albuquerque, NM); Fleming, legal representative, Carol (Albuquerque, NM)
2010-11-23T23:59:59.000Z
A microfabricated bulk wave acoustic bandgap device comprises a periodic two-dimensional array of scatterers embedded within the matrix material membrane, wherein the scatterer material has a density and/or elastic constant that is different than the matrix material and wherein the periodicity of the array causes destructive interference of the acoustic wave within an acoustic bandgap. The membrane can be suspended above a substrate by an air or vacuum gap to provide acoustic isolation from the substrate. The device can be fabricated using microelectromechanical systems (MEMS) technologies. Such microfabricated bulk wave phononic bandgap devices are useful for acoustic isolation in the ultrasonic, VHF, or UHF regime (i.e., frequencies of order 1 MHz to 10 GHz and higher, and lattice constants of order 100 .mu.m or less).
Jackson, Jennifer M.
High-pressure sound velocities and elasticity of aluminous MgSiO3 perovskite to 45 GPa lateral variations of seismic wave speeds in Earth's lower mantle are due at least in part to a chemical, J. M., J. Zhang, J. Shu, S. V. Sinogeikin, and J. D. Bass (2005), High-pressure sound velocities
Topology drives calcium wave propagation in 3D astrocyte networks Jules Lallouette, Hugues Berry
Boyer, Edmond
Topology drives calcium wave propagation in 3D astrocyte networks Jules Lallouette, Hugues Berry themselves inter-connected as networks and communicate via chemical wave propagation. How astrocyte wave work, we investigate the influence of the character- istics of the network topology on wave propagation
Effects of pore fluids in the subsurface on ultrasonic wave propagation
Seifert, P.K.
1998-05-01T23:59:59.000Z
This thesis investigates ultrasonic wave propagation in unconsolidated sands in the presence of different pore fluids. Laboratory experiments have been conducted in the sub-MHz range using quartz sand fully saturated with one or two liquids. Elastic wave propagation in unconsolidated granular material is computed with different numerical models: in one-dimension a scattering model based on an analytical propagator solution, in two dimensions a numerical approach using the boundary integral equation method, in three dimensions the local flow model (LFM), the combined Biot and squirt flow theory (BISQ) and the dynamic composite elastic medium theory (DYCEM). The combination of theoretical and experimental analysis yields a better understanding of how wave propagation in unconsolidated sand is affected by (a) homogeneous phase distribution; (b) inhomogeneous phase distribution, (fingering, gas inclusions); (c) pore fluids of different viscosity; (d) wettabilities of a porous medium. The first study reveals that the main ultrasonic P-wave signatures, as a function of the fraction on nonaqueous-phase liquids in initially water-saturated sand samples, can be explained by a 1-D scattering model. The next study investigates effects of pore fluid viscosity on elastic wave propagation, in laboratory experiments conducted with sand samples saturated with fluids of different viscosities. The last study concentrates on the wettability of the grains and its effect on elastic wave propagation and electrical resistivity.
Constraining the gravitational wave energy density of the Universe using Earth's ring
Coughlin, Michael
2014-01-01T23:59:59.000Z
The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density o...
Variability in Long-Wave Runup as a Function of Nearshore Bathymetric Features
Dunkin, Lauren M.
2011-08-08T23:59:59.000Z
wave setup and runup. The influence of bathymetric features on long-wave runup can be used in evaluating the vulnerability of coastal regions to erosion and dune overtopping, evaluating the changing morphology, and implementing plans to protect...
Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb
Taylor, Alice E [ORNL; Berlijn, Tom [ORNL; Hahn, Steven E [ORNL; May, Andrew F [ORNL; Williams, Travis J [ORNL; Poudel, Lekhanath N [ORNL; Calder, Stuart A [ORNL; Fishman, Randy Scott [ORNL; Stone, Matthew B [ORNL; Aczel, Adam A [ORNL; Cao, Huibo [ORNL; Lumsden, Mark D [ORNL; Christianson, Andrew D [ORNL
2015-01-01T23:59:59.000Z
We report elastic and inelastic neutron scattering measurements of the high-TC ferromagnet Mn(1+delta)Sb. Measurements were performed on a large, TC = 434 K, single crystal with interstitial Mn content of delta=0.13. The neutron diffraction results reveal that the interstitial Mn has a magnetic moment, and that it is aligned antiparallel to the main Mn moment. We perform density functional theory calculations including the interstitial Mn, and find the interstitial to be magnetic in agreement with the diffraction data. The inelastic neutron scattering measurements reveal two features in the magnetic dynamics: i) a spin-wave-like dispersion emanating from ferromagnetic Bragg positions (H K 2n), and ii) a broad, non-dispersive signal centered at forbidden Bragg positions (H K 2n+1). The inelastic spectrum cannot be modeled by simple linear spin-wave theory calculations, and appears to be significantly altered by the presence of the interstitial Mn ions. The results show that the influence of the int
Packing of elastic wires in flexible shells
Vetter, Roman; Herrmann, Hans J
2015-01-01T23:59:59.000Z
The packing problem of long thin filaments that are injected into confined spaces is of fundamental interest for physicists, biologists and materials engineers alike. How linear threads pack and coil is well known only for the ideal case of rigid containers, however. Here, we force long elastic rods into flexible spatial confinement borne by an elastic shell to examine under which conditions recently acquired knowledge on wire packing in rigid spheres breaks down. We find that unlike in rigid cavities, friction plays a key role by giving rise to the emergence of two distinct packing patterns. At low friction, the wire densely coils into an ordered toroidal bundle with semi-ellipsoidal cross section, while at high friction, it packs into a highly disordered, self-similar structure. These two morphologies are shown to be separated by a continuous phase transition.
Packing of elastic wires in flexible shells
Roman Vetter; Falk K. Wittel; Hans J. Herrmann
2015-04-03T23:59:59.000Z
The packing problem of long thin filaments that are injected into confined spaces is of fundamental interest for physicists, biologists and materials engineers alike. How linear threads pack and coil is well known only for the ideal case of rigid containers, however. Here, we force long elastic rods into flexible spatial confinement borne by an elastic shell to examine under which conditions recently acquired knowledge on wire packing in rigid spheres breaks down. We find that unlike in rigid cavities, friction plays a key role by giving rise to the emergence of two distinct packing patterns. At low friction, the wire densely coils into an ordered toroidal bundle with semi-ellipsoidal cross section, while at high friction, it packs into a highly disordered, self-similar structure. These two morphologies are shown to be separated by a continuous phase transition.
Elastic electron scattering from formic acid
Trevisan, Cynthia S.; Orel, Ann E.; Rescigno, Thomas N.
2006-07-31T23:59:59.000Z
Following our earlier study on the dynamics of low energy electron attachment to formic acid, we report the results of elastic low-energy electron collisions with formic acid. Momentum transfer and angular differential cross sections were obtained by performing fixed-nuclei calculations employing the complex Kohn variational method. We make a brief description of the technique used to account for the polar nature of this polyatomic target and compare our results with available experimental data.
Excitation of intense acoustic waves in hexagonal crystals
Alshits, V. I., E-mail: alshits@ns.crys.ras.ru; Bessonov, D. A.; Lyubimov, V. N. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)] [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
2013-11-15T23:59:59.000Z
Resonant excitation of an intense elastic wave using reflection of a pump wave from a free surface of hexagonal crystal is described. A resonance arises in the case of specially chosen propagation geometry where the reflecting boundary slightly deviates from symmetric orientation and the propagation direction of an intense reflected wave is close to that of an exceptional bulk wave, which satisfies the free boundary condition in unperturbed symmetric orientation. It is shown that, in crystals with elastic moduli c{sub 44}>c{sub 66}, a resonance arises when the initial boundary is chosen parallel to the hexagonal axis 6, whereas in crystals characterized by the relation c{sub 44}
Incrocci, Thomas Paul
1970-01-01T23:59:59.000Z
. . . . . . . . , . . . ~ . ~ INTRODUCTION BACKGROUND TO THE PROBLEM Theory of Mountain Waves Mountain Waves and Clear Air Turbulence (CAT). Page iv v vi viii The Vertical Propagation and Transfer of Energy of Mountain Waves into the Stratosphere The Influence of Wind... and wave energy under the influence of wind shear (Booker and Bretherton, 1967). A critical level, if it exists, is the level at which the horizontal phase velocity of the wave equals the mean wind speed. If a wave passes through a criti- cal level...
Environmental bias and elastic curves on surfaces
Jemal Guven; Dulce María Valencia; Pablo Vázquez-Montejo
2014-08-15T23:59:59.000Z
The behavior of an elastic curve bound to a surface will reflect the geometry of its environment. This may occur in an obvious way: the curve may deform freely along directions tangent to the surface, but not along the surface normal. However, even if the energy itself is symmetric in the curve's geodesic and normal curvatures, which control these modes, very distinct roles are played by the two. If the elastic curve binds preferentially on one side, or is itself assembled on the surface, not only would one expect the bending moduli associated with the two modes to differ, binding along specific directions, reflected in spontaneous values of these curvatures, may be favored. The shape equations describing the equilibrium states of a surface curve described by an elastic energy accommodating environmental factors will be identified by adapting the method of Lagrange multipliers to the Darboux frame associated with the curve. The forces transmitted to the surface along the surface normal will be determined. Features associated with a number of different energies, both of physical relevance and of mathematical interest, are described. The conservation laws associated with trajectories on surface geometries exhibiting continuous symmetries are also examined.
Preferred orientation and elastic anisotropy in shales.
Lonardelli, I.; Wenk, H.-R.; Ren, Y.; Univ. of California at Berkeley
2007-03-01T23:59:59.000Z
Anisotropy in shales is becoming an important issue in exploration and reservoir geophysics. In this study, the crystallographic preferred orientation of clay platelets that contributes to elastic anisotropy was determined quantitatively by hard monochromatic X-ray synchrotron diffraction in two different shales from drillholes off the coast of Nigeria. To analyze complicated diffraction images with five different phases (illite/smectite, kaolinite, quartz, siderite, feldspar) and many overlapping peaks, we applied a methodology based on the crystallographic Rietveld method. The goal was to describe the intrinsic physical properties of the sample (phase composition, crystallographic preferred orientation, crystal structure, and microstructure) and compute macroscopic elastic properties by averaging single crystal properties over the orientation distribution for each phase. Our results show that elastic anisotropy resulting from crystallographic preferred orientation of the clay particles can be determined quantitatively. This provides a possible way to compare measured seismic anisotropy and texture-derived anisotropy and to estimate the contribution of the low-aspect ratio pores aligned with bedding.
Coda wave interferometry 1 Coda wave interferometry
Snieder, Roel
Coda wave interferometry 1 Coda wave interferometry An interferometer is an instrument that is sensitive to the interference of two or more waves (optical or acoustic). For example, an optical interferometer uses two interfering light beams to measure small length changes. Coda wave interferometry
Surface wave acoustics of granular packing under gravity
Clement, Eric; Andreotti, Bruno [PMMH, ESPCI, CNRS (UMR 7636) and Univ. Paris 6 and Paris 7, 10 rue Vauquelin, 75005 Paris (France); Bonneau, Lenaic [PMMH, ESPCI, CNRS (UMR 7636) and Univ. Paris 6 and Paris 7, 10 rue Vauquelin, 75005 Paris (France)
2009-06-18T23:59:59.000Z
Due to the non-linearity of Hertzian contacts, the speed of sound in granular matter increases with pressure. For a packing under gravity and in the presence of a free surface, bulk acoustic waves cannot propagate due to the inherent refraction toward the surface (the mirage effect). Thus, only modes corresponding to surface waves (Raleigh-Hertz modes) are able to propagate the acoustic signal. First, based on a non-linear elasticity model, we describe the main features associated to these surface waves. We show that under gravity, a granular packing is from the acoustic propagation point of view an index gradient waveguide that selects modes of two distinct families i.e. the sagittal and transverse waves localized in the vicinity of the free surface. A striking feature of these surface waves is the multi-modal propagation: for both transverse and sagittal waves, we show the existence of a infinite but discrete series of propagating modes. In each case, we determine the mode shape and and the corresponding dispersion relation. In the case of a finite size system, a geometric waveguide is superimposed to the index gradient wave guide. In this later case, the dispersion relations are modified by the appearance of a cut-off frequency that scales with depth. The second part is devoted to an experimental study of surface waves propagating in a granular packing confined in a long channel. This set-up allows to tune a monomodal emission by taking advantage of the geometric waveguide features combined with properly designed emitters. For both sagittal and transverses waves, we were able to isolate a single mode (the fundamental one) and to plot the dispersion relation. This measurements agree well with the Hertzian scaling law as predicted by meanfield models. Furthermore, it allows us to determine quantitatively relations on the elastic moduli. However, we observe that our data yield a shear modulus abnormally weak when compared to several meanfield predictions.
Nonlinear acoustic/seismic waves in earthquake processes
Johnson, Paul A. [Geophysics Group, Los Alamos National Laboratory, Los Alamos National Laboratory, Los Alamos New Mexico 87544 (United States)
2012-09-04T23:59:59.000Z
Nonlinear dynamics induced by seismic sources and seismic waves are common in Earth. Observations range from seismic strong ground motion (the most damaging aspect of earthquakes), intense near-source effects, and distant nonlinear effects from the source that have important consequences. The distant effects include dynamic earthquake triggering-one of the most fascinating topics in seismology today-which may be elastically nonlinearly driven. Dynamic earthquake triggering is the phenomenon whereby seismic waves generated from one earthquake trigger slip events on a nearby or distant fault. Dynamic triggering may take place at distances thousands of kilometers from the triggering earthquake, and includes triggering of the entire spectrum of slip behaviors currently identified. These include triggered earthquakes and triggered slow, silent-slip during which little seismic energy is radiated. It appears that the elasticity of the fault gouge-the granular material located between the fault blocks-is key to the triggering phenomenon.
Dynamics of Bianchi type I elastic spacetimes
Simone Calogero; J. Mark Heinzle
2007-06-26T23:59:59.000Z
We study the global dynamical behavior of spatially homogeneous solutions of the Einstein equations in Bianchi type I symmetry, where we use non-tilted elastic matter as an anisotropic matter model that naturally generalizes perfect fluids. Based on our dynamical systems formulation of the equations we are able to prove that (i) toward the future all solutions isotropize; (ii) toward the initial singularity all solutions display oscillatory behavior; solutions do not converge to Kasner solutions but oscillate between different Kasner states. This behavior is associated with energy condition violation as the singularity is approached.
Lessons from LHC elastic and diffractive data
A. D. Martin; V. A. Khoze; M. G. Ryskin
2014-10-13T23:59:59.000Z
In the light of LHC data, we discuss the global description of all high energy elastic and diffractive data, using a one-pomeron model, but including multi-pomeron interactions. The LHC data indicate the need of a $k_t(s)$ behaviour, where $k_t$ is the gluon transverse momentum along the partonic ladder structure which describes the pomeron. We also discuss tensions in the data, as well as the $t$ dependence of the slope of $d\\sigma_{el}/dt$ in the small $t$ domain.
Elastic and diffractive scattering at D0
Edwards, Tamsin; /Manchester U.
2004-04-01T23:59:59.000Z
The first search for diffractively produced Z bosons in the muon decay channel is presented, using a data set collected by the D0 detector at the Fermilab Tevatron at {radical}s = 1.96 TeV between April and September 2003, corresponding to an integrated luminosity of approximately 110 pb{sup -1}. The first dN/d|t| distribution for proton-antiproton elastic scattering at this c.o.m. energy is also presented, using data collected by the D0 Forward Proton Detector between January and May 2002. The measured slope is reproduced by theoretical predictions.
The effect of elastic strain on M-center distribution in LiF
Wolny, Richard Frank
1962-01-01T23:59:59.000Z
of lithium fluoride, illustrating the Seitz and Knox models of the M-center 3 2. A two dimensional lattice of lithium fluoride, illustrating the F and P -centers. 2 4 3. Prism sub]ected to torque about z-axis 4. Cross-section of a rectangular crystal... was to determine the influence of elastic strain on the production of M-centers in crystals of lithium fluoride. g secondary objective was to observe whether the amount of time that a crystal was strained had any effect on the M-center distribution. Data...
Motivation Elastic Net Computation Elastic-Net and algorithms for computing the
Recht, Ben
Solution Lemma Given data set (y, X) and (1, 2), define an artificial data set (y, X) by X (n+p)Ã?p = (1 + 2 compute the elastic-net estimator ^(enet), and then we construct the adaptive weights by ^wj = (|^j
New Atomic Force Microscope Spectroscopy Probes Local Elasticity...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Materials Characterization New Atomic Force Microscope Spectroscopy Probes Local Elasticity March 04, 2015 Shown is a contact resonance frequency image after nano-oxidation of a...
anomalous elastic behavior: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of symmetry and relevance, we introduce a minimal Landau-Ginzburg-Wilson elastic energy for nematic elastomers. Performing a diagrammatic low temperature expansion, we...
Failure Stress and Apparent Elastic Modulus of Diesel Particulate...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
test specimen geometries and test methods for brittle materials are adapted to DPF architecture to evaluate failure initiation stress and apparent elastic modulus of the ceramics....
Wave motions in unbounded poroelastic solids infused with compressible fluids
Quiligotti, S; dell'Isola, F
2010-01-01T23:59:59.000Z
Looking at rational solid-fluid mixture theories in the context of their biomechanical perspectives, this work aims at proposing a two-scale constitutive theory of a poroelastic solid infused with an inviscid compressible fluid. The propagation of steady-state harmonic plane waves in unbounded media is investigated in both cases of unconstrained solid-fluid mixtures and fluid-saturated poroelastic solids. Relevant effects on the resulting characteristic speed of longitudinal and transverse elastic waves, due to the constitutive parameters introduced, are finally highlighted and discussed.
Comparison of elastic and inelastic analyses
Ammerman, D. J.; Heinstein, M. W.; Wellman, G. W.
1992-01-01T23:59:59.000Z
The use of inelastic analysis methods instead of the traditional elastic analysis methods in the design of radioactive material (RAM) transport packagings leads to a better understanding of the response of the package to mechanical loadings. Thus, better assessment of the containment, thermal protection, and shielding integrity of the package after a structural accident event can be made. A more accurate prediction of the package response can lead to enhanced safety and also allow for a more efficient use of materials, possibly leading to a package with higher capacity or lower weight This paper will discuss the advantages and disadvantages of using inelastic analysis in the design of RAM shipping packages. When using inelastic analysis the entire nonlinear response of the material must be known, including the effects of temperature changes and strain rate. There currently is not an acceptance criteria for this type of analysis that is approved by regulatory agencies. Inelastic analysis acceptance criteria based on failure stress, failure strain, or plastic energy density could be developed. For both elastic and inelastic analyses it is also important to include other sources of stress in the analyses, such as fabrication stresses, thermal stresses, stresses from bolt preloading, and contact stresses at material interfaces.
Possible Zero-Flux Transport induced by Density Waves in a Tube filled with Solid Helium
Kwang-Hua W. Chu
2006-11-07T23:59:59.000Z
Macroscopic derivation of the entrainment in a supersolid cylinder induced by a surface elastic wave (of small amplitude) propagating along the flexible interface is conducted by considering the nonlinear coupling between the interface and the rarefaction effect. We obtain the critical bounds for zero-volume-flow-rate states corresponding to specific rarefaction measure and wave number which is relevant to the rather small critical velocity or disappearance of supersolid flows reported by Rittner and Reppy.
The generalized solutions of the Lama's equations in the case of running loads. The shock waves
Lyudmila A. Alexeyeva
2012-04-07T23:59:59.000Z
The system of Lama's equations is investigated, describing the motion of the elastic media under subsonic, transonic and supersonic velocities of the moving source of distributions, and its decisions in space of generalized vector-functions. The questions are considered connected with arising shock waves, which appear in ambience under supersonic source of distributions. On base of the generalized functions theories the method of the determination of the conditions on gaps of the decisions and their derivatives on shock waves fronts is offered.
Geometrical vs wave optics under gravitational waves
Raymond Angélil; Prasenjit Saha
2015-05-20T23:59:59.000Z
We present some new derivations of the effect of a plane gravitational wave on a light ray. A simple interpretation of the results is that a gravitational wave causes a phase modulation of electromagnetic waves. We arrive at this picture from two contrasting directions, namely null geodesics and Maxwell's equations, or, geometric and wave optics. Under geometric optics, we express the geodesic equations in Hamiltonian form and solve perturbatively for the effect of gravitational waves. We find that the well-known time-delay formula for light generalizes trivially to massive particles. We also recover, by way of a Hamilton-Jacobi equation, the phase modulation obtained under wave optics. Turning then to wave optics - rather than solving Maxwell's equations directly for the fields, as in most previous approaches - we derive a perturbed wave equation (perturbed by the gravitational wave) for the electromagnetic four-potential. From this wave equation it follows that the four-potential and the electric and magnetic fields all experience the same phase modulation. Applying such a phase modulation to a superposition of plane waves corresponding to a Gaussian wave packet leads to time delays.
Slow Waves in Fractures Filled with Viscous Fluid
Korneev, Valeri
2008-01-08T23:59:59.000Z
Stoneley guided waves in a fluid-filled fracture generally have larger amplitudes than other waves, and therefore, their properties need to be incorporated in more realistic models. In this study, a fracture is modeled as an infinite layer of viscous fluid bounded by two elastic half-spaces with identical parameters. For small fracture thickness, I obtain a simple dispersion equation for wave-propagation velocity. This velocity is much smaller than the velocity of a fluid wave in a Biot-type solution, in which fracture walls are assumed to be rigid. At seismic prospecting frequencies and realistic fracture thicknesses, the Stoneley guided wave has wavelengths on the order of several meters and an attenuation Q factor exceeding 10, which indicates the possibility of resonance excitation in fluid-bearing rocks. The velocity and attenuation of Stoneley guided waves are distinctly different at low frequencies for water and oil. The predominant role of fractures in fluid flow at field scales is supported by permeability data showing an increase of several orders of magnitude when compared to values obtained at laboratory scales. These data suggest that Stoneley guided waves should be taken into account in theories describing seismic wave propagation in fluid-saturated rocks.
Are deep-ocean-generated surface-wave microseisms observed on land?
Gerstoft, Peter
-array beamforming. Below 0.2 Hz, modeling and some observations suggest that some deep water-generated elastic p [Latham and Sutton, 1966; Fukao et al., 2010], sediment shear modes [Schreiner and Dorman, 1990 or location. The combination of added wind energy imparted to the waves over time, and/or dispersion
Folding model analysis of pion elastic and inelastic scattering from {sup 6}Li and {sup 12}C
Ebrahim, A. A., E-mail: aebrahim@aun.edu.eg [Assiut University, Physics Department (Egypt)
2013-04-15T23:59:59.000Z
{pi}{sup {+-}}-Nucleus scattering cross sections are calculated applying the Watanabe superposition model with a phenomenological Woods-Saxon potential. The phenomenological potential parameters are searched for {pi}{sup {+-}} scattering from {sup 6}Li and {sup 12}C to reproduce not only differential elastic cross sections but also inelastic and total and reaction cross sections at pion kinetic energies from 50 to 672 MeV. The optical potentials of {sup 6}Li and {sup 12}C are calculated in terms of the alpha particle and deuteron optical potentials. Inelastic scattering has been analyzed using the distorted waves from elastic-scattering data. The values of deformation lengths thus obtained compare very well with the ones reported earlier.
Net Balanced Floorplanning Based on Elastic Energy Model
Nannarelli, Alberto
Net Balanced Floorplanning Based on Elastic Energy Model Wei Liu and Alberto Nannarelli Dept variations can introduce extra signal skew, it is desirable to have floorplans with balanced net delays based on the elastic energy model. The B*-tree, which is based on an ordered binary tree, is used
Rubber Elasticity: Solution of the James-Guth Model
B. E. Eichinger
2015-03-21T23:59:59.000Z
The solution of the many-body statistical mechanical theory of elasticity formulated by James and Guth in the 1940s is presented. The remarkable aspect of the solution is that it gives an elastic free energy that is essentially equivalent to that developed by Flory over a period of several decades.
Hybrid Simulation Modeling to Estimate U.S. Energy Elasticities
Hybrid Simulation Modeling to Estimate U.S. Energy Elasticities by Adam C. Baylin-Stern B.A. & Sc in the estimation of ESUBs from CIMS. Keywords: Elasticity of substitution; hybrid energy-economy model; translog-Stern Degree: Project No.: Master of Resource Management 535 Title of Thesis: Hybrid Simulation Modeling
Elastic nucleon scattering at small angles at LHC energies
S. V. Goloskokov; S. P. Kuleshov; O. V. Selyugin
1997-07-02T23:59:59.000Z
Predictions of the elastic proton-proton cross sections at energies of LHC are calculate on the base of the high energy dynamical model. The growth of $ds/dt$ at fixed transfer momenta are shown. The form of eikonal of elastic hadron scattering at super high energies is discussed.
CAPITAL FOR ENERGY AND INTER-FUEL ELASTICITIES OF SUBSTITUTION
substitution elasticity and inter-fuel substitution elasticities, determine how much a change in the price the standard econometric approach, grounded in behaviorally realistic historical statistics, and linear in the case of switching from oil to natural gas and natural gas to electricity. It was also found that all
Nitrogen Contamination in Elastic Neutron Scattering Songxue Chi,ab
Lynn, Jeffrey W.
Nitrogen Contamination in Elastic Neutron Scattering Songxue Chi,ab Jeffrey W. Lynn,a* Ying Chen a neutron scattering measurement is a contribution to the background, especially in inelastic measurements of having N2 in the sample environment system during elastic neutron scattering measurements on a single
Modeling Elastic Properties in Finite-Element Analysis: How Much
Modeling Elastic Properties in Finite- Element Analysis: How Much Precision Is Needed to Produce analysis was investigated using a finite-element model of a Macaca fascicularis skull. Four finite-element realistically using the orthotropic elastic properties employed in analysis 4. Results suggest that finite-element
Impact of Acid Additives on Elastic Modulus of Viscoelastic Surfactants
Khan, Waqar Ahmad
2012-02-14T23:59:59.000Z
In live acid solutions at concentrations of HCl namely 15-20 wt% HCl, elastic modulus remained quite low as compared to 10-12 wt% HCl concentrations. At 10 wt% HCl concentration, elastic modulus was 3.4 Pa observed whereas at 20 wt% HCl...
Acoustic waves in a Biot-type porous snow model: The fast slow wave in light snow
Sidler, Rolf
2015-01-01T23:59:59.000Z
Wave velocities, attenuation and reflection coefficients in snow can not be explained by the widely used elastic or viscoelastic models for wave propagation. Instead, Biot's model of wave propagation in porous materials should be used. However, the application of Biot's model is difficult due to the large property space of the underlying porous material. Here we use the properties of ice and air as well as empirical relationships to define the properties of snow as a function of porosity. This reduction allows to predict phase velocities and attenuation of the shear- and compressional-waves as functions of porosity or density. For light snow the peculiarity was found that the velocity of the compressional wave of the first kind is lower than the compressional wave of the second kind that is commonly referred to as the "slow" wave. The reversal of the velocities comes with an increase of attenuation for the first compressional wave. This is in line with the common observation that sound is strongly absorbed af...
Elastic moduli of nickel and iron aluminides
Manjigani, Sreedhar
1993-01-01T23:59:59.000Z
waves generated by the PUCOT were used to resonate the samples at ultrasonic frequencies. Longitudinal measurements were made at 100 kHz and the torsional measurements were made at 80 kHz. Tests were conducted from room temperature up to 1100'C...
Elastic Metal Alloy Refrigerants: Thermoelastic Cooling
None
2010-10-01T23:59:59.000Z
BEETIT Project: UMD is developing an energy-efficient cooling system that eliminates the need for synthetic refrigerants that harm the environment. More than 90% of the cooling and refrigeration systems in the U.S. today use vapor compression systems which rely on liquid to vapor phase transformation of synthetic refrigerants to absorb or release heat. Thermoelastic cooling systems, however, use a solid-state material—an elastic shape memory metal alloy—as a refrigerant and a solid to solid phase transformation to absorb or release heat. UMD is developing and testing shape memory alloys and a cooling device that alternately absorbs or creates heat in much the same way as a vapor compression system, but with significantly less energy and a smaller operational footprint.
Phonons and elasticity in critically coordinated lattices
T C Lubensky; C L Kane; Xiaoming Mao; A Souslov; Kai Sun
2015-03-04T23:59:59.000Z
Much of our understanding of vibrational excitations and elasticity is based upon analysis of frames consisting of sites connected by bonds occupied by central-force springs, the stability of which depends on the average number of neighbors per site $z$. When $zzero energy and the number, $N_S$, of states of self stress, in which springs can be under positive or negative tension while forces on sites remain zero, it explores the properties of periodic square, kagome, and related lattices for which $z=z_c$ and the relation between states of self stress and zero modes in periodic lattices to the surface zero modes of finite free lattices (with free boundary conditions). It shows how modifications to the periodic kagome lattice can eliminate all but trivial translational zero modes and create topologically distinct classes, analogous to those of topological insulators, with protected zero modes at free boundaries and at interfaces between different topological classes.
,2) provide a kinematic description of water waves, which to this point means that the conditionsWater Waves Roger Grimshaw May 7, 2003 Abstract A short review of the theory of weakly nonlinear water waves, prepared for the forthcoming Encyclopedia of Nonlinear Science 1 Introduction Water waves
Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry
Berryman, J.G.
2010-05-15T23:59:59.000Z
For elastically noninteracting vertical-fracture sets at arbitrary orientation angles to each other, a detailed model is presented in which the resulting anisotropic fractured medium generally has orthorhombic symmetry overall. Some of the analysis methods and ideas of Schoenberg are emphasized, together with their connections to other similarly motivated and conceptually related methods by Sayers and Kachanov, among others. Examples show how parallel vertical-fracture sets having HTI (horizontal transversely isotropic) symmetry transform into orthotropic fractured media if some subsets of the vertical fractures are misaligned with the others, and then the fractured system can have VTI (vertical transversely isotropic) symmetry if all of the fractures are aligned randomly or half parallel and half perpendicular to a given vertical plane. An orthotropic example having vertical fractures in an otherwise VTI earth system (studied previously by Schoenberg and Helbig) is compared with the other examples treated and it is finally shown how fluids in the fractures affect the orthotropic poroelastic system response to seismic waves. The key result is that fracture-influence parameters are multiplied by a factor of (1-B), where 0 {le} B < 1 is Skempton's second coefficient for poroelastic media. Skempton's B coefficient is itself a measurable characteristic of fluid-saturated porous rocks, depending on porosity, solid moduli, and the pore-fluid bulk modulus. For heterogeneous porous media, connections between the present work and earlier related results of Brown and Korringa are also established.
Huang, Jianbin
Thermo-responsive viscoelastic wormlike micelle to elastic hydrogel transition in dual report a thermo-responsive phase transition from a viscoelastic wormlike micelle solution to an elastic
E-Print Network 3.0 - active site elasticity Sample Search Results
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
; Engineering ; Materials Science 54 Analysis of the elastic behaviour of silica aerogels taken as a percolating system Summary: 289 Analysis of the elastic behaviour of...
Constraining the gravitational wave energy density of the Universe using Earth's ring
Michael Coughlin; Jan Harms
2014-06-04T23:59:59.000Z
The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density of gravitational waves to values in the range 0.035 - 0.15 normalized by the critical energy density of the Universe at frequencies between 0.3mHz and 5mHz, using 10 years of data from the gravimeter network of the Global Geodynamics Project that continuously monitors Earth's oscillations. This work is the first step towards a systematic investigation of the sensitivity of gravimeter networks to gravitational waves. Further advance in gravimeter technology could improve sensitivity of these networks and possibly lead to gravitational-wave detection.
aging elastic material: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
framework predicts the appearance of traveling waves which might account for the propagation of actomyosin contractile waves observed during morphogenesis. Dierkes, Kai;...
the wave model A traveling wave is an organized disturbance
Winokur, Michael
1 waves the wave model A traveling wave is an organized disturbance propagating at a well-defined wave speed v. · In transverse waves the particles of the medium move perpendicular to the direction of wave propagation. · In longitudinal waves the particles of the medium move parallel to the direction
Electron Trapping in Shear Alfven Waves that Power the Aurora
Watt, Clare E. J.; Rankin, Robert [University of Alberta, Edmonton, Alberta (Canada)
2009-01-30T23:59:59.000Z
Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm plasma sheet, electrons become trapped in shear Alfven waves, preventing immediate wave damping. As waves move to regions with larger v{sub Te}/v{sub A}, their parallel electric field decreases, and the trapped electrons escape their influence. The resulting electron distribution functions compare favorably with in situ observations, demonstrating for the first time a self-consistent link between Alfven waves and electrons that form aurora.
Elastic properties of gamma-Pu by resonant ultrasound spectroscopy
Migliori, Albert [Los Alamos National Laboratory; Betts, J [Los Alamos National Laboratory; Trugman, A [Los Alamos National Laboratory; Mielke, C H [Los Alamos National Laboratory; Mitchell, J N [Los Alamos National Laboratory; Ramos, M [Los Alamos National Laboratory; Stroe, I [WORXESTER, MA
2009-01-01T23:59:59.000Z
Despite intense experimental and theoretical work on Pu, there is still little understanding of the strange properties of this metal. We used resonant ultrasound spectroscopy method to investigate the elastic properties of pure polycrystalline Pu at high temperatures. Shear and longitudinal elastic moduli of the {gamma}-phase of Pu were determined simultaneously and the bulk modulus was computed from them. A smooth linear and large decrease of all elastic moduli with increasing temperature was observed. We calculated the Poisson ratio and found that it increases from 0.242 at 519K to 0.252 at 571K.
Effect of elasticity of wall on diffusion in nano channel
Tankeshwar, K., E-mail: tankesh@pu.ac.in [Computer Centre, Panjab University Chandigarh,- 160014 (India); Srivastava, Sunita [Department of Physics, Panjab University, Chandigarh 160014 (India)
2014-04-24T23:59:59.000Z
Confining walls of nano channel are taken to be elastic to study their effect on the diffusion coefficient of fluid flowing through the channel. The wall is elastic to the extent that it responses to molecular pressure exerted by fluid. The model to study diffusion is based on microscopic considerations. Results obtained for fluid confining to 20 atomic diameter width contrasted with results obtained by considering rigid and smooth wall. The effect of roughness of wall on diffusion can be compensated by the elastic property of wall.
A Modified Fermi Model for Wave-Particle Interactions in Plasmas
De Marco, Rossana; Carbone, Vincenzo; Veltri, Pierluigi [Dipartimento di Fisica and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia (CNISM), Universita della Calabria, Ponte P. Bucci Cubo 31C, 87036 Rende (Serbia and Montenegro) (Italy)
2006-03-31T23:59:59.000Z
Wave-particle interactions in plasmas are investigated through a nonlinear map that describes elastic collisions between an ensemble of particles and two barriers. The amplitude of the barriers, proportional to the energy of the wave, can increase or decrease due to the sequence of stochastic collisions. After an initial exponential decrease, the nonlinear strong trapping regime is characterized by low-frequency oscillations of the amplitude of the barriers around a certain saturation value. This is a transitory phenomenon stemming from the dynamical approach towards equilibrium in the wave-particle conservative system.
Steady-state propagation of a Mode III crack in couple stress elastic materials
G. Mishuris; A. Piccolroaz; E. Radi
2012-07-14T23:59:59.000Z
This paper is concerned with the problem of a semi-infinite crack steadily propagating in an elastic solid with microstructures subject to antiplane loading applied on the crack surfaces. The loading is moving with the same constant velocity as that of the crack tip. We assume subsonic regime, that is the crack velocity is smaller than the shear wave velocity. The material behaviour is described by the indeterminate theory of couple stress elasticity developed by Koiter. This constitutive model includes the characteristic lengths in bending and torsion and thus it is able to account for the underlying microstructure of the material as well as for the strong size effects arising at small scales and observed when the representative scale of the deformation field becomes comparable with the length scale of the microstructure, such as the grain size in a polycrystalline or granular aggregate. The present analysis confirms and extends earlier results on the static case by including the effects of crack velocity and rotational inertia. By adopting the criterion of maximum total shear stress, we discuss the effects of microstructural parameters on the stability of crack propagation.
Measurement of the analysing power in proton-proton elastic scattering at small angles
Z. Bagdasarian; D. Chiladze; S. Dymov; A. Kacharava; G. Macharashvili; S. Barsov; R. Gebel; B. Gou; M. Hartmann; I. Keshelashvili; A. Khoukaz; P. Kulessa; A. Kulikov; A. Lehrach; N. Lomidze; B. Lorentz; R. Maier; D. Mchedlishvili; S. Merzliakov; S. Mikirtychyants; M. Nioradze; H. Ohm; M. Papenbrock; D. Prasuhn; F. Rathmann; V. Serdyuk; V. Shmakova; R. Stassen; H. Stockhorst; I. I. Strakovsky; H. Ströher; M. Tabidze; A. Täschner; S. Trusov; D. Tsirkov; Yu. Uzikov; Yu. Valdau; C. Wilkin; R. L. Workman
2014-10-28T23:59:59.000Z
The proton analysing power in $\\vec{p}p$ elastic scattering has been measured at small angles at COSY-ANKE at 796 MeV and five other beam energies between 1.6 and 2.4 GeV using a polarised proton beam. The asymmetries obtained by detecting the fast proton in the ANKE forward detector or the slow recoil proton in a silicon tracking telescope are completely consistent. Although the analysing power results agree well with the many published data at 796 MeV, and also with the most recent partial wave solution at this energy, the ANKE data at the higher energies lie well above the predictions of this solution at small angles. An updated phase shift analysis that uses the ANKE results together with the World data leads to a much better description of these new measurements.
Determination of elastic properties of a film-substrate system by using the neural networks
Xu Baiqiang; Shen Zhonghua; Ni Xiaowu; Wang Jijun; Guan Jianfei; Lu Jian [Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Faculty of Science, Jiangsu University, Zhenjiang 212013 (China); Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China); Faculty of Science, Jiangsu University, Zhenjiang 212013 (China); Department of Applied Physics, Nanjing University of Science and Technology, Nanjing 210094 (China)
2004-12-20T23:59:59.000Z
An inverse method based on artificial neural network (ANN) is presented to determine the elastic properties of films from laser-genrated surface waves. The surface displacement responses are used as the inputs for the ANN model; the outputs of the ANN are the Young's modulus, density, Poisson's ratio, and thickness of the film. The finite element method is used to calculate the surface displacement responses in a film-substrate system. Levenberg Marquardt algorithm is used as numerical optimization to speed up the training process for the ANN model. In this method, the materials parameters are not recovered from the dispersion curves but rather directly from the transient surface displacement. We have also found that this procedure is very efficient for determining the materials parameters of layered systems.
Effect of conformations on charge transport in a thin elastic tube
Balakrishnan, Radha
2008-01-01T23:59:59.000Z
We study the effect of conformations on charge transport in a thin elastic tube. Using the Kirchhoff model for a tube with any given Poisson ratio, cross-sectional shape and intrinsic twist, we obtain a class of exact solutions for its conformation. The tube's torsion is found in terms of its intrinsic twist and its Poisson ratio, while its curvature satisfies a nonlinear differential equation which supports exact {\\it periodic} solutions in the form of Jacobi elliptic functions, which we call {\\it conformon lattice} solutions. These solutions typically describe conformations with loops. Each solution induces a corresponding quantum effective {\\it periodic} potential in the Schr\\"{o}dinger equation for an electron in the tube. The wave function describes the delocalization of the electron along the central axis of the tube. We discuss some possible applications of this novel mechanism of charge transport.
Effect of conformations on charge transport in a thin elastic tube
Radha Balakrishnan; Rossen Dandoloff
2008-03-24T23:59:59.000Z
We study the effect of conformations on charge transport in a thin elastic tube. Using the Kirchhoff model for a tube with any given Poisson ratio, cross-sectional shape and intrinsic twist, we obtain a class of exact solutions for its conformation. The tube's torsion is found in terms of its intrinsic twist and its Poisson ratio, while its curvature satisfies a nonlinear differential equation which supports exact {\\it periodic} solutions in the form of Jacobi elliptic functions, which we call {\\it conformon lattice} solutions. These solutions typically describe conformations with loops. Each solution induces a corresponding quantum effective {\\it periodic} potential in the Schr\\"{o}dinger equation for an electron in the tube. The wave function describes the delocalization of the electron along the central axis of the tube. We discuss some possible applications of this novel mechanism of charge transport.
Quasi-elastic neutrino charged-current scattering cross sections on oxygen
A. V. Butkevich; S. A. Kulagin
2007-10-26T23:59:59.000Z
The charged-current quasi-elastic scattering of muon neutrinos on oxygen target is computed for neutrino energies between 200 MeV and 2.5 GeV using the relativistic distorted-wave impulse approximation with relativistic optical potential, which was earlier successfully applied to describe electron-nucleus data. We study both neutrino and electron processes and show that the reduced exclusive cross sections for neutrino and electron scattering are similar. The comparison with the relativistic Fermi gas model (RFGM), which is widely used in data analyses of neutrino experiments, shows that the RFGM fails completely when applied to exclusive cross section data and leads to overestimated values of inclusive and total cross sections. We also found significant nuclear-model dependence of exclusive, inclusive and total cross sections for about 1 GeV energy.
Iwo Bialynicki-Birula
2005-08-26T23:59:59.000Z
Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, the photon wave function exists as long as it can be precisely defined and made useful.
Elastic Z^0 production at HERA
Luca Stanco
2014-10-13T23:59:59.000Z
The production of $Z^{0}$ bosons in the reaction $eparrow eZ^{0}p^{(*)}$, where $p^{(*)}$ stands for a proton or a low-mass nucleon resonance, has been studied in $ep$ collisions at HERA using the ZEUS detector. The analysis is based on a data sample collected between 1996 and 2007, amounting to 496\\, pb$^{-1}$ of integrated luminosity. The $Z^{0}$ was measured in the hadronic decay mode. The elasticity of the events was ensured by a cut on $\\eta_{{\\rm max}} 3.0$, where $\\eta_{{\\rm max}}$ is the maximum pseudorapidity of energy deposits in the calorimeter defined with respect to the proton beam direction. A signal was observed at the $Z^{0}$ mass. The cross section of the reaction $ep arrow eZ^{0}p^{(*)}$ was measured to be $\\sigma (ep arrow eZ^{0}p^{(*)}) = {\\rm 0.13 \\pm{0.06} ({\\rm stat.}) \\pm{0.01} ({\\rm syst.})}\\, {\\rm pb}$, in agreement with the Standard Model prediction of $0.16\\, {\\rm pb}$. This is the first measurement of $Z^{0}$ production in $ep$ collisions. In this paper we report the already published ZEUS result by adding the sensitivities of the most recent similar results from CMS and ATLAS.
Random parking, Euclidean functionals, and rubber elasticity
Antoine Gloria; Mathew D. Penrose
2012-03-06T23:59:59.000Z
We study subadditive functions of the random parking model previously analyzed by the second author. In particular, we consider local functions $S$ of subsets of $\\mathbb{R}^d$ and of point sets that are (almost) subadditive in their first variable. Denoting by $\\xi$ the random parking measure in $\\mathbb{R}^d$, and by $\\xi^R$ the random parking measure in the cube $Q_R=(-R,R)^d$, we show, under some natural assumptions on $S$, that there exists a constant $\\bar{S}\\in \\mathbb{R}$ such that % $$ \\lim_{R\\to +\\infty} \\frac{S(Q_R,\\xi)}{|Q_R|}\\,=\\,\\lim_{R\\to +\\infty}\\frac{S(Q_R,\\xi^R)}{|Q_R|}\\,=\\,\\bar{S} $$ % almost surely. If $\\zeta \\mapsto S(Q_R,\\zeta)$ is the counting measure of $\\zeta$ in $Q_R$, then we retrieve the result by the second author on the existence of the jamming limit. The present work generalizes this result to a wide class of (almost) subadditive functions. In particular, classical Euclidean optimization problems as well as the discrete model for rubber previously studied by Alicandro, Cicalese, and the first author enter this class of functions. In the case of rubber elasticity, this yields an approximation result for the continuous energy density associated with the discrete model at the thermodynamic limit, as well as a generalization to stochastic networks generated on bounded sets.
Rogue Wave Modes for the Long Wave-Short Wave Resonance Kwok Wing CHOW*(1)
1 Rogue Wave Modes for the Long Wave-Short Wave Resonance Model Kwok Wing CHOW*(1) , Hiu Ning CHAN.45.Yv; 47.35.Fg ABSTRACT The long wave-short wave resonance model arises physically when the phase velocity of a long wave matches the group velocity of a short wave. It is a system of nonlinear evolution
Longitudinal Wave Propagation in Relativistic Two-fluid Plasmas around Reissner-Nordstrom Black Hole
Md. Atiqur Rahman
2010-11-28T23:59:59.000Z
The 3+1 spacetime formulation of general relativity is used to investigate the transverse waves propagating in a plasma influenced by the gravitational field of Reissner-Nordstrom black hole, as explained in an earlier paper, to take account of relativistic effects due to the event horizon. Here, a local approximation is used to investigate the one-dimensional radial propagation of longitudinal waves. We derive the dispersion relation for these waves and solve it numerically for the wave number k.
Determination of Elastic Twist in Horizontal Axis Wind Turbines (HAWTs)
Stoddard, F.; Nelson, V.; Starcher, K.; Andrews, B.
2006-06-01T23:59:59.000Z
This report presents the results of a project at the Alternative Energy Institute (AEI) which measured and calculated the elastic twist of three representative composite horizontal-axis blades: Carter 300, Gougeon ESI 54, and UTRC 8 kW.
Elastic properties of superconducting MAX phases from first principles calculations
I. R. Shein; A. L. Ivanovskii
2010-06-03T23:59:59.000Z
Using first-principles density functional calculations, a systematic study on the elastic properties for all known superconducting MAX phases (Nb2SC, Nb2SnC, Nb2AsC, Nb2InC, Mo2GaC and Ti2InC) was performed. As a result, the optimized lattice parameters, independent elastic constants, indicators of elastic anisotropy and brittle/ductile behavior as well as the so-called machinability indexis were calculated. We derived also bulk and shear moduli, Young's moduli, and Poisson's ratio for ideal polycrystalline MAX aggregates. The results obtained were discussed in comparison with available theoretical and experimental data and elastic parameters for other layered superconductors.
Kinematic quantities of finite elastic and plastic deformation
T. Fülöp; P. Ván
2012-03-05T23:59:59.000Z
Kinematic quantities for finite elastic and plastic deformations are defined via an approach that does not rely on auxiliary elements like reference frame and reference configuration, and that gives account of the inertial-noninertial aspects explicitly. These features are achieved by working on Galilean spacetime directly. The quantity expressing elastic deformations is introduced according to its expected role: to measure how different the current metric is from the relaxed/stressless metric. Further, the plastic kinematic quantity is the change rate of the stressless metric. The properties of both are analyzed, and their relationship to frequently used elastic and plastic kinematic quantities is discussed. One important result is that no objective elastic or plastic quantities can be defined from deformation gradient.
Instrumentation for multiaxial mechanical testing of inhomogeneous elastic membranes
Herrmann, Ariel Marc
2006-01-01T23:59:59.000Z
This thesis presents the design, development, and construction of an instrument for biaxial mechanical testing of inhomogeneous elastic membranes. The instrument incorporates an arrangement of linear motion stages for ...
Acoustic modes in metallic nanoparticles: Atomistic versus elasticity modeling
Combe, Nicolas; Saviot, Lucien [CNRS, CEMES (Centre d'Elaboration des Materiaux et d'Etudes Structurales), BP 94347, 29 Rue J. Marvig, F-31055 Toulouse, France and Universite de Toulouse, UPS, F-31055 Toulouse (France); Institut Carnot de Bourgogne, UMR 5209 CNRS - Universite de Bourgogne, 9 Avenue A. Savary, BP 47870, F-21078 Dijon Cedex (France)
2009-07-15T23:59:59.000Z
The validity of the linear elasticity theory is examined at the nanometer scale by investigating the vibrational properties of silver and gold nanoparticles whose diameters range from about 1.5-4 nm. Comparing the vibration modes calculated by elasticity theory and atomistic simulation based on the embedded-atom method, we first show that the anisotropy of the stiffness tensor in elastic calculation is essential to ensure a good agreement between elastic and atomistic models. Second, we illustrate the reduction in the number of vibration modes due to the diminution of the number of atoms when reducing the nanoparticles size. Finally, we exhibit a breakdown of the frequency-spectra scaling of the vibration modes and attribute it to surface effects. Some critical sizes under which such effects are expected, depending on the material and the considered vibration modes, are given.
Actin network architecture and elasticity in lamellipodia of melanoma cells
Schmidt, Volker
Actin network architecture and elasticity in lamellipodia of melanoma cells Frank Fleischer1 melanoma cells. This method is based on fitting multi-layer geometrical statistical models to electron
Exploiting Covariate Similarity in Sparse Regression via the Pairwise Elastic Net
Low, Steven H.
. Furthermore, un- like the Lasso, the Elastic Net can yield a sparse esti- mate with more than n non-zero477 Exploiting Covariate Similarity in Sparse Regression via the Pairwise Elastic Net Alexander to regression regulariza- tion called the Pairwise Elastic Net is pro- posed. Like the Elastic Net, it simultane
Exploiting Covariate Similarity in Sparse Regression via the Pairwise Elastic Net
Blei, David M.
, the Elastic Net can yield a sparse esti- mate with more than n non-zero weights (Efron et al., 2004). One canExploiting Covariate Similarity in Sparse Regression via the Pairwise Elastic Net Alexander Lorbert- tion called the Pairwise Elastic Net is pro- posed. Like the Elastic Net, it simultane- ously performs
Strange Quark Contribution to the Nucleon Spin from Electroweak Elastic Scattering Data
S. F. Pate; J. P. Schaub; D. P. Trujillo
2012-08-29T23:59:59.000Z
The total contribution of strange quarks to the intrinsic spin of the nucleon can be determined from a measurement of the strange-quark contribution to the nucleon's elastic axial form factor. We have studied the strangeness contribution to the elastic vector and axial form factors of the nucleon, using elastic electroweak scattering data. Specifically, we combine elastic $\
Elastic energy of proteins and the stages of protein folding
Lei, Jinzhi
2010-01-01T23:59:59.000Z
We propose a universal elastic energy for proteins, which depends only on the radius of gyration $R_{g}$ and the residue number $N$. It is constructed using physical arguments based on the hydrophobic effect and hydrogen bonding. Adjustable parameters are fitted to data from the computer simulation of the folding of a set of proteins using the CSAW (conditioned self-avoiding walk) model. The elastic energy gives rise to scaling relations of the form $R_{g}\\sim N^{\
Mathur, Manikandan S.
Internal waves are a ubiquitous and significant means of momentum and energy transport in the oceans, atmosphere, and astrophysical bodies. Here, we show that internal wave propagation in nonuniform density stratifications, ...
Mercier, Matthieu J.
We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (Exp. Fluids, vol. 42, 2007, pp. 123–130). This ...
Measurement of np elastic scattering spin-spin correlation parameters at 484, 634, and 788 MeV
Garnett, R.W.
1989-03-01T23:59:59.000Z
The spin-spin correlation parameters C/sub LL/ and C/sub SL/ were measured for np elastic scattering at the incident neutron kinetic energy of 634 MeV. Good agreement was obtained with previously measured data. Additionally, the first measurement of the correlation parameter C/sub SS/ was made at the three energies, 484, 634, and 788 MeV. It was found that the new values, in general, do not agree well with phase shift predictions. A study was carried out to determine which of the isospin-0 partial waves will be affected by this new data. It was found that the /sup 1/P/sub 1/ partial wave will be affected significantly at all three measurement energies. At 634 and 788 MeV, the /sup 3/S/sub 1/ phase shifts will also change. 29 refs., 21 figs., 16 tabs.
Torsional waves propagation in an initially stressed dissipative cylinder
M. M. Selim
2009-03-28T23:59:59.000Z
The present paper has been framed to show the effect of damping on the propagation of torsional waves in an initially stressed, dissipative, incompressible cylinder of infinite length. A governing equation has been formulated on Biot's incremental deformation theory. The velocities of torsional waves are obtained as complex ones, in which real part gives the phase velocity of propagation and corresponding imaginary part gives the damping. The study reveals that the damping of the medium has strong effect in the propagation of torsional wave. Since every medium has damping so it is more realistic to use the damped wave equation instead of the undamped wave equation. The study also shows that the velocity of propagation of such waves depend on the presence of initial stress. The influences of damping and initial stresses are shown separately.
Degasperis, Antonio; Aceves, Alejandro B
2015-01-01T23:59:59.000Z
We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.
Internal wave instability: Wave-wave versus wave-induced mean flow interactions
Sutherland, Bruce
, known as parametric sub- harmonic instability, results generally when a disturbance of one frequency imparts energy to disturbances of half that frequency.13,14 Generally, a plane periodic internal wave, energy from primary waves is transferred, for example, to waves with half frequency. Self
Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino
Merlino, Robert L.
Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino Department of Physics and Astronomy with their announcement that: "We find that a new type of sound wave, namely, the dust-acoustic waves, can appear" [1 and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some
Performance Assessment of the Wave Dragon Wave Energy Converter
Hansen, René Rydhof
Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performanceMar, Nissum Bredning, Hanstholm, North Sea, Ekofisk, Wave-to-wire, Wave energy. I. INTRODUCTION The wave
Krauklis wave in a stack of alternating fluid-elastic layers
Korneev, V.A.
2013-01-01T23:59:59.000Z
of the material parameters: Geofisica internacional: Revistade la Union Geofisica Mexicana auspiciada porel Instituto de Geofisica de la Universidad Nacional
Elastic-wave identification of penetrable obstacles using shape-material sensitivity framework
Guzina, Bojan
in general has been the subject of intensive mathematical and computational research [40,26,13,16], only Palaiseau Cedex, France b Department of Civil Engineering, University of Minnesota, Minneapolis, MN 55455-material sensitivity Elastodynamics Identification Inclusion Boundary element method Constrained optimization a b s t r
Gravity, capillary and dilational wave mode resonance at a visco-elastic two-fluid interface
Brown, Susan Jayne, 1967-
2005-01-01T23:59:59.000Z
(cont.) space corresponding to experimental conditions to thereby interpret the experimental results. We tested this method on noisy simulated data sets and then applied it to published experimental data sets. We designed ...
Measurement of the antineutrino neutral-current elastic differential cross section
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Aguilar-Arevalo, A. ?A.; Brown, B. ?C.; Bugel, L.; Cheng, G.; Church, E. ?D.; Conrad, J. ?M.; Dharmapalan, R.; Djurcic, Z.; Finley, D. ?A.; Ford, R.; Garcia, F. ?G.; Garvey, G. ?T.; Grange, J.; Huelsnitz, W.; Ignarra, C.; Imlay, R.; Johnson, R. ?A.; Karagiorgi, G.; Katori, T.; Kobilarcik, T.; Louis, W. ?C.; Mariani, C.; Marsh, W.; Mills, G. ?B.; Mirabal, J.; Moore, C. ?D.; Mousseau, J.; Nienaber, P.; Osmanov, B.; Pavlovic, Z.; Perevalov, D.; Polly, C. ?C.; Ray, H.; Roe, B. ?P.; Russell, A. ?D.; Shaevitz, M. ?H.; Spitz, J.; Stancu, I.; Tayloe, R.; Van de Water, R. ?G.; Wascko, M. ?O.; White, D. ?H.; Wickremasinghe, D. ?A.; Zeller, G. ?P.; Zimmerman, E. ?D.
2015-01-01T23:59:59.000Z
We report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (d??-barN??-barN/dQ2) on CH2 by the MiniBooNE experiment using the largest sample of antineutrino neutral current elastic candidate events ever collected. The ratio of the antineutrino to neutrino neutral current elastic scattering cross sections and a ratio of the antineutrino neutral current elastic to antineutrino charged current quasi elastic cross sections are also presented.
On the S-wave piD-scattering length in the relativistic field theory model of the deuteron
A. N. Ivanov; N. I. Troitskaya; M. Faber; H. Oberhummer
1997-01-16T23:59:59.000Z
The S-wave scattering length of the strong pion-deuteron (pi D) scattering is calculated in the relativistic field theory model of the deuteron suggested in [1,2].The theoretical result agrees well with the experimental data. The important role of the Delta-resonance contribution to the elastic pi D-scattering is confirmed.
Stages of destruction and elastic compression of granular nanoporous carbon medium at high pressures
I. M. Neklyudov; O. P. Ledenyov; N. B. Bobrova; A. A. Chupikov
2015-05-14T23:59:59.000Z
The granular nanoporous carbon medium, made of the cylindrical coal granules of the adsorbent of SKT 3, at an influence by the high pressures from 1MPa to 3GPa has been researched. The eight consecutive stages of the materials specific volume change, which is characterized by a certain dependence of the volume change on the pressure change, have been registered. It is shown that there is a linear dependence on the double log log plot of the materials specific volume change on the pressure for an every stage of considered process. The two stages are clearly distinguished such as a stage of materials mechanical destruction, and a stage of elastic compression of material without the disintegration of structure at a nanscale. The hysteresis dependence of the materials specific volume change on the pressure change at the pressure decrease is observed. The small disperse coal dust particles jettisoning between the high pressure cell and the base plate was observed, resulting in the elastic stress reduction in relation to the small disperse coal dust particles volume. The obtained research data can be used to improve the designs of air filters for the radioactive chemical elements absorption at the NPP with the aims to protect the environment.
Coastal Wave Generation and Wave Breaking over Terrain: Two Problems in Mesoscale Wave Dynamics
Qian, Tingting
2010-07-14T23:59:59.000Z
Two problems in mesoscale wave dynamics are addressed: (i) wave-turbulence interaction in a breaking mountain wave and (ii) gravity wave generation associated with coastal heating gradients. The mean and turbulent structures in a breaking mountain...
Coastal Wave Generation and Wave Breaking over Terrain: Two Problems in Mesoscale Wave Dynamics
Qian, Tingting
2010-07-14T23:59:59.000Z
Two problems in mesoscale wave dynamics are addressed: (i) wave-turbulence interaction in a breaking mountain wave and (ii) gravity wave generation associated with coastal heating gradients. The mean and turbulent structures in a breaking mountain...
Pacôme Delva; Marie-Christine Angonin; Philippe Tourrenc
2006-09-20T23:59:59.000Z
We calculate and compare the response of light wave interferometers and matter wave interferometers to gravitational waves. We find that metric matter wave interferometers will not challenge kilometric light wave interferometers such as Virgo or LIGO, but could be a good candidate for the detection of very low frequency gravitational waves.
Time Reversal in Solids (Linear and Nonlinear Elasticity): Multimedia Resources in Time Reversal
DOE Data Explorer [Office of Scientific and Technical Information (OSTI)]
Dynamic nonlinear elastic behavior, nonequilibrium dynamics, first observed as a curiosity in earth materials has now been observed in a great variety of solids. The primary manifestations of the behavior are characteristic wave distortion, and slow dynamics, a recovery process to equilibrium that takes place linearly with the logarithm of time, over hours to days after a wave disturbance. The link between the diverse materials that exhibit nonequilibrium dynamics appears to be the presence of soft regions, thought to be 'damage' at many scales, ranging from order 10-9 m to 10-1 m at least. The regions of soft matter may be distributed as in a rock sample, or isolated, as in a sample with a single crack [LANLhttp://www.lanl.gov/orgs/ees/ees11/geophysics/nonlinear/nonlinear.shtml]. The Geophysics Group (EES-11) at Los Alamos National Laboratory has posted two or more multimedia items under each of the titles below to demonstrate aspects of their work: 1) Source Reconstruction Using Time Reversal; 2) Robustness and Efficiency of Time Reversal Acoustics in Solid Media; 3) Audio Example of Time Reversal - Speech Privacy; 4) Crack Imagining with Time Reversal - Experimental Results; 5) Time Reversal of the 2004 (M9.0) Sumatra Earthquake.
Mode III interfacial crack in the presence of couple stress elastic materials
Andrea Piccolroaz; Gennady Mishuris; Enrico Radi
2011-04-02T23:59:59.000Z
In this paper we are concerned with the problem of a crack lying at the interface between dissimilar materials with microstructure undergoing antiplane deformations. The micropolar behaviour of the materials is described by the theory of couple stress elasticity developed by Koiter (1964). This constitutive model includes the characteristic lengths in bending and torsion and thus it is able to account for the underlying microstructure of the two materials. We perform an asymptotic analysis to investigate the behaviour of the solution near the crack tip. It turns out that the stress singularity at the crack tip is strongly influenced by the microstructural parameters and it may or may not show oscillatory behaviour depending on the ratio between the characteristic lengths.
Price-elastic demand in deregulated electricity markets
Siddiqui, Afzal S.
2003-05-01T23:59:59.000Z
The degree to which any deregulated market functions efficiently often depends on the ability of market agents to respond quickly to fluctuating conditions. Many restructured electricity markets, however, experience high prices caused by supply shortages and little demand-side response. We examine the implications for market operations when a risk-averse retailer's end-use consumers are allowed to perceive real-time variations in the electricity spot price. Using a market-equilibrium model, we find that price elasticity both increases the retailers revenue risk exposure and decreases the spot price. Since the latter induces the retailer to reduce forward electricity purchases, while the former has the opposite effect, the overall impact of price responsive demand on the relative magnitudes of its risk exposure and end-user price elasticity. Nevertheless, price elasticity decreases cumulative electricity consumption. By extending the analysis to allow for early settlement of demand, we find that forward stage end-user price responsiveness decreases the electricity forward price relative to the case with price-elastic demand only in real time. Moreover, we find that only if forward stage end-user demand is price elastic will the equilibrium electricity forward price be reduced.
Cycloidal Wave Energy Converter
Stefan G. Siegel, Ph.D.
2012-11-30T23:59:59.000Z
This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.
Elastic and plastic properties of soils influencing the design of rigid pavements
Khuri, Fuad I.
1954-01-01T23:59:59.000Z
B 1 ?? i t i J *>. . i - i ~ i ' - o D? e? .u c f.M fC L )^ - ; 4 '6 . CBBTB ? 3 1 J >4 * ' ? z . d . 4... s ? ? -W flj ? ? f t 3 f t ? c g ? S
Elastic and plastic properties of soils influencing the design of rigid pavements
Khuri, Fuad I.
1954-01-01T23:59:59.000Z
s ............................................................................... 1 3 3 3 7 8 11 11 12 16 19 26 33 33 47 55 EX III. DETERMINATION OF THE PERTINENT STRESS-STRAIN CHARACTERISTICS OF THE S O I L .................................................. 82 A . P repara tion of S a m p l e... s .................................................................82 B. Unconfined C om press ion T e s t s .................................................. 85 C. Var ied Latera l P r e s su r e T r iax ia l T e s t s ............................. 88 D. Repetitive Load T riax ia l T e...
Elastic breakup cross sections of well-bound nucleons
K. Wimmer; D. Bazin; A. Gade; J. A. Tostevin; T. Baugher; Z. Chajecki; D. Coupland; M. A. Famiano; T. K. Ghosh; G. F. Grinyer M. E. Howard; M. Kilburn; W. G. Lynch; B. Manning; K. Meierbachtol; P. Quarterman; A. Ratkiewicz; A. Sanetullaev; R. H. Showalter; S. R. Stroberg; M. B. Tsang; D. Weisshaar; J. Winkelbauer; R. Winkler; M. Youngs
2014-12-07T23:59:59.000Z
The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the re- moval of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.
Temperature relationship of the elastic constants of vanadium
Belousov, O.K.
1987-09-01T23:59:59.000Z
Information on the elastic constants of vanadium and their temperature relationship is limited and ambiguous. This article gives the values of these characteristics for VEL-2 electron beam remelted vanadium with a purity of about 99.8%. The elastic properties were measured in heating from 20 to 1600/sup 0/C in a vacuum. The relationship of the modulus of elasticity to temperature has two almost linear portions in the 20-300 and 300-1350/sup 0/C ranges and then a more intense reduction in it is observed. The shear modulus drops sharply starting with 800/sup 0/C and decreases to G = 36 kN/mm/sup 2/ at 1600/sup 0/C. Poisson's ratio has values close to 0.3. Its most significant increase starts with 1400/sup 0/C.e
Biaxial Deformations of Rubber: Entanglements or Elastic Fluctuations?
Xiangjun Xing
2010-11-01T23:59:59.000Z
The classical theory of rubber elasticity fails in the regime of large deformation. The un- derlying physical mechanism has been under debate for long time. In this work, we test the recently proposed mechanism of thermal elastic fluctuations by Xing, Goldbart and Radzi- hovsky1 against the biaxial stress-strain data of three distinct polymer networks with very different network structures, synthesized by Urayama2 and Kawabata3 respectively. We find that both the two parameters version and the one-parameter version of the XGR theory provide satisfactory description of the elasticity in whole deformation range. For comparison, we also fit the same sets of data using the slip-link model by Edwards and Vilgis with four parameters. The fitting qualities of two theories are found to be comparable.
Spatial Distributions of Local Elastic Moduli Near the Jamming Transition
Hideyuki Mizuno; Leonardo E. Silbert; Matthias Sperl
2015-04-10T23:59:59.000Z
Recent progress in studies of the nanoscale mechanical responses in amorphous solids has highlighted a strong degree of heterogeneity in the elastic moduli of thermal glassy systems. In this contribution, using computer simulations, we study the elastic heterogeneities in athermal amorphous solids, composed of isotropic, static, sphere packings near the jamming transition. We employ techniques based on linear response theory which avoid the need to invoke any explicit deformation. Not only do we validate these procedures by reproducing established scaling laws for the global elastic moduli, but our technique reveals new power-law behaviors in the spatial fluctuations of the local moduli. The local moduli are randomly distributed in space, and are described by Gaussian probability distributions all the way down to the transition point. However, the moduli fluctuations grow as the jamming threshold is approached, through which we are able to identify a characteristic length scale, associated with the shear modulus heterogeneities.
Impedance of rigid bodies in one-dimensional elastic collisions
Santos, Janilo; Nelson, Osman Rosso
2012-01-01T23:59:59.000Z
In this work we study the problem of one-dimensional elastic collisions of billiard balls, considered as rigid bodies, in a framework very different from the classical one presented in text books. Implementing the notion of impedance matching as a way to understand eficiency of energy transmission in elastic collisions, we find a solution which frames the problem in terms of this conception. We show that the mass of the ball can be seen as a measure of its impedance and verify that the problem of maximum energy transfer in elastic collisions can be thought of as a problem of impedance matching between different media. This approach extends the concept of impedance, usually associated with oscillatory systems, to system of rigid bodies.
Nonlinear spherical Alfven waves
Ulf Torkelsson; G. Christopher Boynton
1997-09-23T23:59:59.000Z
We present an one-dimensional numerical study of Alfven waves propagating along a radial magnetic field. Neglecting losses, any spherical Alfven wave, no matter how small its initial amplitude is, becomes nonlinear at sufficiently large radii. From previous simulations of Alfven waves in plane parallel atmospheres we did expect the waves to steepen and produce current sheets in the nonlinear regime, which was confirmed by our new calculations. On the other hand we did find that even the least nonlinear waves were damped out almost completely before 10 solar radii. A damping of that kind is required by models of Alfven wave-driven winds from old low-mass stars as these winds are mainly accelerated within a few stellar radii.
Beyond mean-field study of elastic and inelastic electron scattering off nuclei
J. M. Yao; M. Bender; P. -H. Heenen
2015-01-21T23:59:59.000Z
Electron scattering provides a powerful tool to determine charge distributions and transition densities of nuclei. This tool will soon be available for short-lived neutron-rich nuclei. [Purpose] Beyond mean-field methods have been successfully applied to the study of excitation spectra of nuclei in the whole nuclear chart. These methods permit to determine energies and transition probabilities starting from an effective in-medium nucleon-nucleon interaction but without other phenomenological ingredients. Such a method has recently been extended to calculate the charge density of nuclei deformed at the mean-field level of approximation [J. M. Yao et al., Phys. Rev. C86, 014310 (2012)]. The aim of this work is to further extend the method to the determination of transition densities between low-lying excited states. [Method] The starting point of our method is a set of Hartree-Fock-Bogoliubov wave functions generated with a constraint on the axial quadrupole moment and using a Skyrme energy density functional. Correlations beyond the mean field are introduced by projecting mean-field wave functions on angular-momentum and particle number and by mixing the symmetry restored wave functions.[Results] We give in this paper detailed formulae derived for the calculation of densities and form factors. These formulae are rather easy to obtain when both initial and final states are $0^+$ states but are far from being trivial when one of the states has a finite $J$-value. Illustrative applications to $^{24}$Mg and to the even-mass $^{58-68}$Ni have permitted to analyse the main features of our method, in particular the effect of deformation on densities and form factors. An illustration calculation of both elastic and inelastic scattering form factors is presented....
Non-contacting transfer of elastic energy into explosive simulants for dynamic property estimation
Greeney, Nathan S.; Strovink, Kurt M.; Scales, John A. [Physics Department, Colorado School of Mines, Golden, Colorado 80401 (United States); Jessop, Andrew M.; Stuart Bolton, J. [Ray W. Herrick Laboratories, Purdue University, West Lafayette, Indiana 47907-2099 (United States); Watson, Christopher C.; Adams, Douglas E. [Purdue Center for Systems Integrity, Purdue University, Lafayette, Indiana 47905 (United States)
2014-05-21T23:59:59.000Z
Non-contacting acoustical methods can be used to extract various material properties of liquid or solid samples without disturbing the sample. These methods are useful even in the lab since they do not involve coupling anything to the sample, which might change its properties. A forteriori, when dealing with potentially dangerous materials, non-contacting methods may be the only safe solutions to mechanical characterization. Here, we show examples of using laser ultrasound to remotely insonify and monitor the elastic properties of several granular explosive simulants. The relatively short near-infrared laser pulse length (a few hundred nanoseconds) provides a broad-band thermoelastic source of ultrasound; we intentionally stay in the thermoelastic regime to avoid damaging the material. Then, we use a scanning laser Doppler vibrometer to measure the ultrasonic response of the sample. LDV technology is well established and very sensitive at ultrasonic frequencies; atomic level motions can be measured with modest averaging. The resulting impulse response of the explosive simulant can be analyzed to determine decay rates and wave speeds, with stiffer samples showing faster wave speeds and lower decay rates. On the other hand, at the low-frequency end of the acoustic spectrum, we use an electronically phased array to couple into a freely suspended sample's normal modes. This allows us to gently heat up the sample (3?°C in just under 5 min, as shown with a thermal IR camera). In addition to the practical interest in making the sample more chemically visible through heat, these two measurements (low-frequency resonant excitation vs high-frequency wave propagation) bracket the frequency range of acoustic non-destructive evaluation methods available.
Structure-borne sound Flexural wave (bending wave)
Berlin,Technische Universität
1 Structure-borne sound · Flexural wave (bending wave) »One dimensional (beam) +(/x)dx +(/x)dx = (/x) (/x)dx=(2/x2)dx Mz +(Mz/x)dx Mz vy Fy Fy +(Fy/x)dx Structure-borne sound · Bending wave flexural wave #12;2 Structure-borne sound · Two obliquely propagating waves + - + + - + - Structure
Wave Propagation Theory 2.1 The Wave Equation
2 Wave Propagation Theory 2.1 The Wave Equation The wave equation in an ideal fluid can be derived #12;66 2. Wave Propagation Theory quantities of the quiescent (time independent) medium are identified perturbations is much smaller than the speed of sound. 2.1.1 The Nonlinear Wave Equation Retaining higher
Wave momentum flux parameter: a descriptor for nearshore waves
US Army Corps of Engineers
Wave momentum flux parameter: a descriptor for nearshore waves Steven A. Hughes* US Army Engineer Available online 7 October 2004 Abstract A new parameter representing the maximum depth-integrated wave momentum flux occurring over a wave length is proposed for characterizing the wave contribution
Low-energy elastic electron interactions with pyrimidine
Palihawadana, Prasanga; Sullivan, James; Buckman, Stephen [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Brunger, Michael [Centre for Antimatter-Matter Studies, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Institute of Mathematical Sciences, University of Malaya, 50603, Kuala Lumpur (Malaysia); Winstead, Carl; McKoy, Vincent [A A Noyes Laboratory of Chemical Physics, California Institute of Technology, Pasadena, California 91125 (United States); Garcia, Gustavo [Consejo Superior de Investigaciones Cientificas, Serrano 113-bis, ES-28006 Madrid (Spain); Blanco, F. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, ES-28040 Madrid (Spain)
2011-12-15T23:59:59.000Z
We present results of measurements and calculations of elastic electron scattering from pyrimidine in the energy range 3-50 eV. Absolute differential and integral elastic cross sections have been measured using a crossed electron-molecule beam spectrometer and the relative flow technique. The measured cross sections are compared with results of calculations using the well-known Schwinger variational technique and an independent-atom model. Agreement between the measured differential cross sections and the results of the Schwinger calculations is good at lower energies but less satisfactory at higher energies where inelastic channels that should be open are kept closed in the calculations.
First-principles elastic properties of (alpha)-Pu
Soderlind, P; Klepeis, J
2009-02-18T23:59:59.000Z
Density-functional electronic-structure calculations have been used to investigate the ambient pressure and low temperature elastic properties of the ground-state {alpha} phase of plutonium metal. The electronic structure and correlation effects are modeled within a fully relativistic antiferromagnetic treatment with a generalized gradient approximation for the electron exchange and correlation functional. The 13 independent elastic constants, for the monoclinic {alpha}-Pu system, are calculated for the observed geometry. A comparison of the results with measured data from recent resonant ultrasound spectroscopy for a cast sample is made.
First-principles elastic properties of (alpha)-Pu
Soderlind, P; Klepeis, J E
2008-11-04T23:59:59.000Z
Density-functional electronic structure calculations have been used to investigate the ambient pressure and low temperature elastic properties of the ground-state {alpha} phase of plutonium metal. The electronic structure and correlation effects are modeled within a fully relativistic anti-ferromagnetic treatment with a generalized gradient approximation for the electron exchange and correlation functionals. The 13 independent elastic constants, for the monoclinic {alpha}-Pu system, are calculated for the observed geometry. A comparison of the results with measured data from resonant ultrasound spectroscopy for a cast sample is made.
Accurate hydrogen depth profiling by reflection elastic recoil detection analysis
Verda, R. D. (Raymond D.); Tesmer, Joseph R.; Nastasi, Michael Anthony,; Bower, R. W. (Robert W.)
2001-01-01T23:59:59.000Z
A technique to convert reflection elastic recoil detection analysis spectra to depth profiles, the channel-depth conversion, was introduced by Verda, et al [1]. But the channel-depth conversion does not correct for energy spread, the unwanted broadening in the energy of the spectra, which can lead to errors in depth profiling. A work in progress introduces a technique that corrects for energy spread in elastic recoil detection analysis spectra, the energy spread correction [2]. Together, the energy spread correction and the channel-depth conversion comprise an accurate and convenient hydrogen depth profiling method.
Elastic anisotropy in multifilament Nb3Sn superconducting wires
Scheuerlein, C; Alknes, P; Arnau, G; Bjoerstad, R; Bordini, B
2015-01-01T23:59:59.000Z
The elastic anisotropy caused by the texture in the Nb3Sn filaments of PIT and RRP wires has been calculated by averaging the estimates of Voigt and Reuss, using published Nb3Sn single crystal elastic constants and the Nb3Sn grain orientation distribution determined in both wire types by Electron Backscatter Diffraction. At ambient temperature the calculated Nb3Sn E-moduli in axial direction in the PIT and the RRP wire are 130 GPa and 140 GPa, respectively. The calculated E-moduli are compared with tensile test results obtained for the corresponding wires and extracted filament bundles.
Mercier, Matthieu J; Mathur, Manikandan; Gostiaux, Louis; Peacock, Thomas; Dauxois, Thierry
2015-01-01T23:59:59.000Z
We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (2007). This mechanism, which involves a tunable source comprised of oscillating plates, has so far been used for a few fundamental studies of internal waves, but its full potential has yet to be realized. Our studies reveal that this approach is capable of producing a wide variety of two-dimensional wave fields, including plane waves, wave beams and discrete vertical modes in finite-depth stratifications. The effects of discretization by a finite number of plates, forcing amplitude and angle of propagation are investigated, and it is found that the method is remarkably efficient at generating a complete wave field despite forcing only one velocity component in a controllable manner. We furthermore find that the nature of the radiated wave field is well predicted using Fourier transforms of the spatial structure of the wave generator.
Directed Relativistic Blast Wave
Andrei Gruzinov
2007-04-23T23:59:59.000Z
A spherically symmetrical ultra-relativistic blast wave is not an attractor of a generic asymmetric explosion. Spherical symmetry is reached only by the time the blast wave slows down to non-relativistic velocities, when the Sedov-Taylor-von Neumann attractor solution sets in. We show however, that a directed relativistic explosion, with the explosion momentum close to the explosion energy, produces a blast wave with a universal intermediate asymptotic -- a selfsimilar directed ultra-relativistic blast wave. This universality might be of interest for the astrophysics of gamma-ray burst afterglows.
Evidence for 2D Solitary Sound Waves in a Lipid Controlled Interface and its Biological Implications
Shamit Shrivastava; Matthias F. Schneider
2014-05-08T23:59:59.000Z
Biological membranes by virtue of their elastic properties should be capable of propagating localized perturbations analogous to sound waves. However, the existence and the possible role of such waves in communication in biology remains unexplored. Here we report the first observations of 2D solitary elastic pulses in lipid interfaces, excited mechanically and detected by FRET. We demonstrate that the nonlinearity near a maximum in the susceptibility of the lipid monolayer results in solitary pulses that also have a threshold for excitation. These experiments clearly demonstrate that the state of the interface regulates the propagation of pulses both qualitatively and quantitatively. We elaborate on the striking similarity of the observed phenomenon to nerve pulse propagation and a thermodynamic basis of cell signaling in general.
Wave Energy challenges and possibilities
© Wave Energy challenges and possibilities By: Per Resen Steenstrup www.WaveStarEnergy.com Risø-R-1608(EN) 161 #12;© Wave energy is an old story.... The first wave energy patent is 200 years old. Over the last 100 years more than 200 new wave energy devices have been developped and more than 1.000 patents
Frequency-dependent attenuation and elasticity in unconsolidated earth materials: effect of damping
Yanqing Hu; Hernán A. Makse; John J. Valenza; David L. Johnson
2014-10-20T23:59:59.000Z
We use the Discrete Element Method (DEM) to understand the underlying attenuation mechanism in granular media, with special applicability to the measurements of the so-called effective mass developed earlier. We consider that the particles interact via Hertz-Mindlin elastic contact forces and that the damping is describable as a force proportional to the velocity difference of contacting grains. We determine the behavior of the complex-valued normal mode frequencies using 1) DEM, 2) direct diagonalization of the relevant matrix, and 3) a numerical search for the zeros of the relevant determinant. All three methods are in strong agreement with each other. The real and the imaginary parts of each normal mode frequency characterize the elastic and the dissipative properties, respectively, of the granular medium. We demonstrate that, as the interparticle damping, $\\xi$, increases, the normal modes exhibit nearly circular trajectories in the complex frequency plane and that for a given value of $\\xi$ they all lie on or near a circle of radius $R$ centered on the point $-iR$ in the complex plane, where $R\\propto 1/\\xi$. We show that each normal mode becomes critically damped at a value of the damping parameter $\\xi \\approx 1/\\omega_n^0$, where $\\omega_n^0$ is the (real-valued) frequency when there is no damping. The strong indication is that these conclusions carry over to the properties of real granular media whose dissipation is dominated by the relative motion of contacting grains. For example, compressional or shear waves in unconsolidated dry sediments can be expected to become overdamped beyond a critical frequency, depending upon the strength of the intergranular damping constant.
Wave-Corpuscle Mechanics for Electric Charges
Babin, Anatoli; Figotin, Alexander
2010-01-01T23:59:59.000Z
superposition in nonlinear wave dynamics. Rev. Math. Phys.6. Babin, A. , Figotin, A. : Wave-corpuscle mechanics forV. , Fortunato, D. : Solitary waves in the nonlinear wave
Wave Energy Resource Analysis for Use in Wave Energy Conversion
Pastor, J.; Liu, Y.; Dou, Y.
2014-01-01T23:59:59.000Z
In order to predict the response of wave energy converters an accurate representation of the wave climate resource is crucial. This paper gives an overview of wave resource modeling techniques as well as detailing a methodology for estimating...
Harmonic generation of gravitational wave induced Alfven waves
Mats Forsberg; Gert Brodin
2007-11-26T23:59:59.000Z
Here we consider the nonlinear evolution of Alfven waves that have been excited by gravitational waves from merging binary pulsars. We derive a wave equation for strongly nonlinear and dispersive Alfven waves. Due to the weak dispersion of the Alfven waves, significant wave steepening can occur, which in turn implies strong harmonic generation. We find that the harmonic generation is saturated due to dispersive effects, and use this to estimate the resulting spectrum. Finally we discuss the possibility of observing the above process.
Effect of a nonlinear power take off on a wave energy converter
Bailey, Helen Louise
2011-11-22T23:59:59.000Z
This thesis is titled The influence of a nonlinear Power Take Off on a Wave Energy Converter. It looks at the effect that having a nonlinear Power Take Off (PTO) has on an inertial referenced, slack moored, point absorber, ...
Analysis of PS-converted wave seismic data in the presence of azimuthal anisotropy
Liu, Weining
2014-11-27T23:59:59.000Z
Shear-wave splitting and azimuthal variations of seismic attributes are two major anisotropic effects induced by vertically-aligned fractures. They both have influences on seismic data processing and interpretation, and ...
Bending Elasticity of Anti-Parallel b-Sheets Seungho Choe and Sean X. Sun
Sun, Sean
fluctuations of the structure at room temperature. By matching the probability distributions of elastic strainsBending Elasticity of Anti-Parallel b-Sheets Seungho Choe and Sean X. Sun Department of Mechanical
RIS-M-2586 ELASTIC-PLASTIC FRACTURE MECHANICS ANALYSIS OF A CT-SPECIMEN
RISØ-M-2586 ELASTIC-PLASTIC FRACTURE MECHANICS ANALYSIS OF A CT-SPECIMEN - A TWO-DIMENSIONAL APPROACH Gunner C. Larsen Abstract. This report documents the results obtained from an elastic-plastic
Elastic-plastic analysis of the transition divertor joint for high performance divertor target plate
Navaei, Dara
2011-01-01T23:59:59.000Z
locations of principal plastic strains in 3D warm and coldthe ARIES Team “Elastic-Plastic analysis of the transitionSAN DIEGO Elastic-Plastic Analysis of the Transition
Tirtaatmadja, Viyada
2007-01-23T23:59:59.000Z
The dynamics of drop formation and pinch-off have been investigated for a series of low viscosity elastic fluids possessing similar shear viscosities, but differing substantially in elastic properties. On initial approach ...
Efficient control of series elastic actuators through the exploitation of resonant modes
Albert, Kevin B. (Kevin Bjorn)
2007-01-01T23:59:59.000Z
This thesis explores the efficiency potential inherent to series elastic actuators during oscillatory tasks. Series elastic actuators have a spring intentionally placed at the actuator output that provides good force ...
Boyer, Edmond
-bounded positive-definite matrix-valued random fields in the context of mesoscale modeling of heterogeneous elastic; Heterogeneous materials; Apparent elasticity tensor; Mesoscale modeling; Random field; Non-Gaussian. $ J
Elastic scattering at CERN collider energies and the Chou-Yang model
Bellandi F , J.; Brunetto, S.Q.; Covolan, R.J.M.; Menon, M.J.; Pimentel, B.M.; Padua, A.B.
1987-05-01T23:59:59.000Z
The p-barp elastic scattering at ..sqrt..s-bar = 546 and 630 GeV is analyzed in the Chou-Yang model with Martin's real part in the elastic amplitude.
E-Print Network 3.0 - anomalous quasi-elastic electron Sample...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Sample search results for: anomalous quasi-elastic electron Page: << < 1 2 3 4 5 > >> 1 Neutron scattering study of the quasi-elastic spectral width in CeMg, CeMg3 and NdMg3...
Analysis of Automobile Travel Demand Elasticities with Respect to Travel Cost
Analysis of Automobile Travel Demand Elasticities with Respect to Travel Cost Oak Ridge National relationships between automobile travel demand and cost to analyze the elasticities of the demand for personal
H. Dussan; M. H. Mahzoon; R. J. Charity; W. H. Dickhoff; A. Polls
2014-10-09T23:59:59.000Z
Employing a recently-developed dispersive optical model (DOM) which allows a complete description of experimental data both above (up to 200 MeV) and below the Fermi energy in $^{40}$Ca, we demonstrate that elastic nucleon-nucleus scattering data constrain the spectral strength in the continuum of orbits that are nominally bound in the independent-particle model. In the energy domain between 0 and 200 MeV, the integrated strength or depletion number is highly sensitive to the separation of the IPM orbit to the scattering continuum. This sensitivity is determined by the influence of the surface-absorption properties of the DOM self-energy. For an ab initio calculation employing the self-energy of the charge-dependent Bonn (CDBonn) interaction which only includes the effect of short-range correlations, no such sensitivity is obtained and a depletion of 4% is predicted between 0 and 200 MeV irrespective of the orbit. The ab initio spectral strength generated with the CDBonn interaction approaches the empirical DOM spectral strength at 200 MeV. Both spectral distributions allow for an additional 3-5% of the strength at even higher energies which is associated with the influence of short-range correlations. We suggest that the non-local form of the DOM allows for an analysis of elastic-nucleon-scattering data that directly determines the depletion of bound orbits. While obviously relevant for the analysis of elastic nucleon scattering on stable targets, this conclusion holds equally well for experiments involving rare isotopes in inverse kinematics as well as experiments with electrons on atoms or molecules.
J X Zheng-Johansson; P-I Johansson
2006-08-27T23:59:59.000Z
The electromagnetic component waves, comprising together with their generating oscillatory massless charge a material particle, will be Doppler shifted when the charge hence particle is in motion, with a velocity $v$, as a mere mechanical consequence of the source motion. We illustrate here that two such component waves generated in opposite directions and propagating at speed $c$ between walls in a one-dimensional box, superpose into a traveling beat wave of wavelength ${\\mit\\Lambda}_d$$=(\\frac{v}{c}){\\mit\\Lambda}$ and phase velocity $c^2/v+v$ which resembles directly L. de Broglie's hypothetic phase wave. This phase wave in terms of transporting the particle mass at the speed $v$ and angular frequency ${\\mit\\Omega}_d=2\\pi v /{\\mit\\Lambda}_d$, with ${\\mit\\Lambda}_d$ and ${\\mit\\Omega}_d$ obeying the de Broglie relations, represents a de Broglie wave. The standing-wave function of the de Broglie (phase) wave and its variables for particle dynamics in small geometries are equivalent to the eigen-state solutions to Schr\\"odinger equation of an identical system.
Elastic modulus of viral nanotubes Zhibin Ge,2
Wu, Shin-Tson
TMV nano- tubes. The initial elastic response of TMV nanotubes can be described by finite. INTRODUCTION Tobacco mosaic virus TMV is a hollow tubular structure formed by the self-assembly of 2130 nano- particles because it combines high sensitivity in applying and measuring forces and high
Buckling-induced encapsulation of structured elastic shells under pressure
Reis, Pedro Miguel
functional origami-like structures at the nano- and microscales (1Â3), including encapsulation using hollow for dynamic actuation using a swelling-induced elastic instability (16). There are a few existing hollow shell example of a hollow shell structure satisfying geometric compatibility for gating holes. It enables
Revenue Management for Cognitive Spectrum Underlay Networks: An Interference Elasticity
Huang, Jianwei
to the large body of work on uplink power control with pricing for CDMA networks (e.g., [5][10] and a recent a total received interference power constraint at the primary user's receiver. The transmission power1 Revenue Management for Cognitive Spectrum Underlay Networks: An Interference Elasticity
Addiction to car use and dynamic elasticity measures in France
Boyer, Edmond
1 Addiction to car use and dynamic elasticity measures in France Roger Collet* Matthieu de: Transportation, Car use, Consumption, Addiction, Panel, GMM. JEL Classification: C23, D12. * Corresponding author-le-Grand Cedex, France. Tel: +33(1) 45 92 55 73. E-mail: rcollet@inrets.fr. ** Université Paris-Est. Institut
Two typical processes ... Isentropic("mechanical" reversible, elastic)
Kostic, Milivoje M.
is coupled and accompanied with energy conversions and dissipation to heat/thermal energy ... Carnot cycle12/28/2011 1 Two typical processes ... · Isentropic("mechanical" reversible, elastic) where useful provides for de-coupling of thermal energy from other types and, YES!, for reversible heat transfer
VISUALIZATION OF ELASTIC BODY DYNAMICS FOR AUTOMOTIVE ENGINE SIMULATIONS
drives, hydraulic systems and gas flow in combustion chambers. It also includes AVL Excite, a soft- ware-body system: linear elastic bod- ies (crankshaft, conrod, etc) connected by joints (bear- ings, dampers, etc a brief overview of the typical workflow of a user working with Excite be- fore the 3D view
Generalised elastic nets Miguel A. Carreira-Perpi~nan
Carreira-PerpiÃ±Ã¡n, Miguel Ã.
for combinatorial optimisation and has been applied, among other problems, to biological modelling. It has an energy the elastic net model to an arbitrary quadratic tension term, e.g. derived from a discretised differential, and show that the model is sensitive to the choice of finite difference scheme that represents
Preconditioned Conjugate Gradient Methods for Three Dimensional Linear Elasticity
Waterloo, University of
Preconditioned Conjugate Gradient Methods for Three Dimensional Linear Elasticity by John Kenneth. A brief review is also made of stopping criteria for conjugate gradient solvers. One method based and tested with poor results. iv #12;Contents 1 Introduction 1 1.1 Preconditioned Conjugate Gradient Methods
RESEARCH ARTICLE Bubble growth in visco-elastic magma: implications
Lyakhovsky, Vladimir
RESEARCH ARTICLE Bubble growth in visco-elastic magma: implications to magma fragmentation modulus, bubble growth is slow and follows an exponential law in a viscous growth regime, while for low friction and the Mohr-Coulomb failure theory, and a strain related one based on fibre elongation
MEASUREMENTS OF THE DEUTERON ELASTIC STRUCTURE FUNCTION AQ2
's continuous electron beam with energies from 3.2 to 4.4 GeV, and currents from 5 to 120 A. The beam current. CHUDAKOVa Thomas Je erson National Accelerator Facility, Newport News, Va, US The deuteron elastic structure of the experimental areas Hall A of the Thomas Je erson National Accelerator Facility JLab, using the Jlab
Neutron-deuteron elastic scattering and three-nucleon force
Chtangeev, Maxim B
2005-01-01T23:59:59.000Z
The differential cross section for neutron-deuteron elastic scattering was measured at six angles over the center-of-mass angular range 65? - 1300? and incident neutron energies 140 - 240 MeV at the LANSCE/WNR facility of ...
analysis elastic recoil: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
analysis elastic recoil First Page Previous Page 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Next Page Last Page Topic Index 1 Optimal foil shape for neutron...
ELASTIC ROCK PROPERTIES OF TIGHT GAS SANDSTONES FOR RESERVOIR CHARACTERIZATION
to successfully produce low permeability gas reservoirs. My study links rock physics to well log and seismic data shales to reservoir sandstones. Typically, the presence of gas-saturated sandstones lowers the Vp/Vs evenELASTIC ROCK PROPERTIES OF TIGHT GAS SANDSTONES FOR RESERVOIR CHARACTERIZATION AT RULISON FIELD
Secondary dust density waves excited by nonlinear dust acoustic waves
Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, M. [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States)
2012-08-15T23:59:59.000Z
Secondary dust density waves were observed in conjunction with high amplitude (n{sub d}/n{sub d0}>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, {Gamma}{approx}1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.
Byers, Loren W. [Los Alamos National Laboratory; Ten Cate, James A. [Los Alamos National Laboratory; Johnson, Paul A. [Los Alamos National Laboratory
2012-06-28T23:59:59.000Z
Nonlinear resonance ultrasound spectroscopy experiments conducted on concrete cores, one chemically and mechanically damaged by alkali-silica reactivity, and one undamaged, show that this material displays highly nonlinear wave behavior, similar to many other damaged materials. They find that the damaged sample responds more nonlinearly, manifested by a larger resonant peak and modulus shift as a function of strain amplitude. The nonlinear response indicates that there is a hysteretic influence in the stress-strain equation of state. Further, as in some other materials, slow dynamics are present. The nonlinear response they observe in concrete is an extremely sensitive indicator of damage. Ultimately, nonlinear wave methods applied to concrete may be used to guide mixing, curing, or other production techniques, in order to develop materials with particular desired qualities such as enhanced strength or chemical resistance, and to be used for damage inspection.
Possibility of s-wave pion condensates in neutron stars revisited
A. Ohnishi; D. Jido; T. Sekihara; K. Tsubakihara
2009-09-05T23:59:59.000Z
We examine possibilities of pion condensation with zero momentum (s-wave condensation) in neutron stars by using the pion-nucleus optical potential U and the relativistic mean field (RMF) models. We use low-density phenomenological optical potentials parameterized to fit deeply bound pionic atoms or pion-nucleus elastic scatterings. Proton fraction (Y_p) and electron chemical potential (mu_e) in neutron star matter are evaluated in RMF models. We find that the s-wave pion condensation hardly takes place in neutron stars and especially has no chance if hyperons appear in neutron star matter and/or b_1 parameter in U has density dependence.
Adler, Thomas A. (Corvallis, OR)
1996-01-01T23:59:59.000Z
The invention pertains a method of determining elastic and plastic mechanical properties of ceramics, intermetallics, metals, plastics and other hard, brittle materials which fracture prior to plastically deforming when loads are applied. Elastic and plastic mechanical properties of ceramic materials are determined using spherical indenters. The method is most useful for measuring and calculating the plastic and elastic deformation of hard, brittle materials with low values of elastic modulus to hardness.
Recirculation in multiple wave conversions
Brizard, A.J.
2008-01-01T23:59:59.000Z
model lies with the simple wave energy conservation law itthe recirculation of wave energy introduces interference e?particles, the tertiary-wave energy may be negative and thus
Arnold Schwarzenegger CALIFORNIA OCEAN WAVE
Arnold Schwarzenegger Governor CALIFORNIA OCEAN WAVE ENERGY ASSESSMENT Prepared For: California this report as follows: Previsic, Mirko. 2006. California Ocean Wave Energy Assessment. California Energy Systems Integration Â· Transportation California Ocean Wave Energy Assessment is the final report
LETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the
Udgaonkar, Jayant B.
#12;LETTER doi:10.1038/nature12267 Elastic energy storage in the shoulder and the evolution of high elastic energy storage and release at the shoulder. These features first appear together approximately 2. Elastic energy storage has been shown to be an important source of poweramplification formanyhigh
Elasticity measurements on minerals: a review ROSS J. ANGEL1,*, JENNIFER M. JACKSON2
Jackson, Jennifer M.
Elasticity measurements on minerals: a review ROSS J. ANGEL1,*, JENNIFER M. JACKSON2 , HANS J 91125, USA 3 Deutsches Geoforschungszentrum, 14473 Potsdam, Germany Abstract: The elasticity of minerals in the experimental methods used to determine the elastic properties of minerals. Not only have new techniques become
ON THE DERIVATION OF NONLINEAR SHELL MODELS FROM THREE-DIMENSIONAL ELASTICITY
, 74G10, 74G65. Key words and phrases. Elasticity, shells, energy minimization, Koiter. hal-00392028ON THE DERIVATION OF NONLINEAR SHELL MODELS FROM THREE-DIMENSIONAL ELASTICITY Cristinel Mardare. A nonlinearly elastic shell is modeled either by the nonlinear three- dimensional shell model or by a nonlinear
High-throughput generation of hydrogel microbeads with varying elasticity for cell encapsulation
Zandstra, Peter W.
High-throughput generation of hydrogel microbeads with varying elasticity for cell encapsulation a microfluidic approach for high-throughput generation of 3D microenvironments with different elasticity for studies of cell fate. The generation of agarose microgels with different elastic moduli was achieved by (i
Jacobsen, Steven D.
Elastic properties of transparent nano-polycrystalline diamond measured by GHz-ultrasonic interferometry Sphere resonance Nano-polycrystalline diamond NPD Elastic properties Superhard materials a b s t r a c t The sound velocities and elastic moduli of transparent nano-polycrystalline diamond (NPD) have
THE ELASTIC-PLASTIC MECHANICS OF CRACK EXTENSION James R. Rice*
THE ELASTIC-PLASTIC MECHANICS OF CRACK EXTENSION James R. Rice* ABSTRACT This paper briefly reviews progres~in the elastic plastic analysisof crack extension. Analytical results for plane strain and plane stress deformation fields are noted, and elastic-plastic fracture instability as well as transitional
FINITE-ELEMENT FORMULATIONS FOR PROBLEMS OF LARGE ELASTIC-PLASTIC DEFORMATION
FINITE-ELEMENT FORMULATIONS FOR PROBLEMS OF LARGE ELASTIC-PLASTIC DEFORMATION R. M. MCM~EKING and J elastic-plastic flow.The method is based on Hill's variational principle for incremental deformations in a manner which allows any conventions finite element program, for "small strain" elastic-plastic analysis
PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL
Clapham, Lynann
PLASTIC VERSUS ELASTIC DEFORMATION EFFECTS ON MAGNETIC BARKHAUSEN NOISE IN STEEL C.-G. STEFANITA, D) AbstractÐA study was performed to dierentiate the eects of elastic and plastic deformation on magnetic samples subjected to varying degrees of uniaxial elastic and plastic deformation up to H40% strain
ARTICLE IN PRESS 1 Effects of testing methods and conditions on the elastic
Al-Shayea, Naser Abdul-Rahman
on the elastic 2 properties of limestone rock 3 Naser A. Al-Shayea* 4 Department of Civil Engineering, King Fahd. The objective is to compare elastic properties (elastic modulus and Poisson's ratio) for 12 limestone rockfundamental mechanical properties of rock materials 34required for the analysis and design of engineering 35
Influence of flavor oscillations on neutrino beam instabilities
Mendonça, José Tito; Bret, Antoine
2014-01-01T23:59:59.000Z
We consider the collective neutrino plasma interactions, and study the electron plasma instabilities produced by a nearly mono-energetic neutrino beam in a plasma. We describe the mutual influence of neutrino flavor oscillations and electron plasma waves. We show that the neutrino flavor oscillations are not only perturbed by electron plasmas waves, but also contribute to the dispersion relation and the growth rates of neutrino beam instabilities.
Internal energy relaxation in shock wave structure
Josyula, Eswar, E-mail: Eswar.Josyula@us.af.mil; Suchyta, Casimir J. [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Boyd, Iain D. [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Vedula, Prakash [University of Oklahoma, Norman, Oklahoma 73019 (United States)] [University of Oklahoma, Norman, Oklahoma 73019 (United States)
2013-12-15T23:59:59.000Z
The Wang Chang-Uhlenbeck (WCU) equation is numerically integrated to characterize the internal structure of Mach 3 and Mach 5 shock waves in a gas with excitation in the internal energy states for the treatment of inelastic collisions. Elastic collisions are modeled with the hard sphere collision model and the transition rates for the inelastic collisions modified appropriately using probabilities based on relative velocities of the colliding particles. The collision integral is evaluated by the conservative discrete ordinate method [F. Tcheremissine, “Solution of the Boltzmann kinetic equation for high-speed flows,” Comput. Math. Math. Phys. 46, 315–329 (2006); F. Cheremisin, “Solution of the Wang Chang-Uhlenbeck equation,” Dokl. Phys. 47, 487–490 (2002)] developed for the Boltzmann equation. For the treatment of the diatomic molecules, the internal energy modes in the Boltzmann equation are described quantum mechanically given by the WCU equation. As a first step in the treatment of the inelastic collisions by the WCU equation, a two- and three-quantum system is considered to study the effect of the varying of (1) the inelastic cross section and (2) the energy gap between the quantum energy states. An alternative method, the direct simulation Monte Carlo method, is used for the Mach 3 shock wave to ensure the consistency of implementation in the two methods and there is an excellent agreement between the two methods. The results from the WCU implementation showed consistent trends for the Mach 3 and Mach5 standing shock waves simulations. Inelastic contributions change the downstream equilibrium state and allow the flow to transition to the equilibrium state further upstream.
Bowen, Ray M.
2014-01-22T23:59:59.000Z
of classical porous media models. Chapter 2 introduces the essentials of the theory of mixtures. Chapters 3,4 and 5 exploit the theory of mixtures to formulate various models of porous elastic materials. Chapter 6 is concerned with establishing connections...
B. V. Ivanov
1997-05-21T23:59:59.000Z
A coordinate transformation is found which diagonalizes the axisymmetric pp-waves. Its effect upon concrete solutions, including impulsive and shock waves, is discussed.
Wave-wave interactions in solar type III radio bursts
Thejappa, G. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); MacDowall, R. J. [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)
2014-02-11T23:59:59.000Z
The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.
Elastic properties of saturated porous rocks with aligned fractures
2003-12-02T23:59:59.000Z
This unexpected result is caused by the wave-induced flow of fluids between pores and fractures. ..... For non-fractured rock setting fracture weaknesses. DN and ...
Lyakhovsky, Vladimir
1987-01-01T23:59:59.000Z
-elastic isotropic models (Zaichenko et al. 1984; Schukin 1984). Interpretation of seismic results based on the Hooke in seismic zones implies that the traditional interpretation of geophysical investigations basedGeophys. J. R. astr. SOC.(1987) 91,429437 On the relation between seismic wave velocity and stress
Full wave simulations of lower hybrid wave propagation in tokamaks
Wright, John C.
Full wave simulations of lower hybrid wave propagation in tokamaks J. C. Wright , P. T. Bonoli , C hybrid (LH) waves have the attractive property of damping strongly via electron Landau resonance. Consequently these waves are well-suited to driving current in the plasma periphery where the electron
Decay of helical Kelvin waves on a quantum vortex filament
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-07-15T23:59:59.000Z
We study the dynamics of helical Kelvin waves moving along a quantum vortex filament driven by a normal fluid flow. We employ the vector form of the quantum local induction approximation (LIA) due to Schwarz. For an isolated filament, this is an adequate approximation to the full Hall-Vinen-Bekarevich-Khalatnikov dynamics. The motion of such Kelvin waves is both translational (along the quantum vortex filament) and rotational (in the plane orthogonal to the reference axis). We first present an exact closed form solution for the motion of these Kelvin waves in the case of a constant amplitude helix. Such solutions exist for a critical wave number and correspond exactly to the Donnelly-Glaberson instability, so perturbations of such solutions either decay to line filaments or blow-up. This leads us to consider helical Kelvin waves which decay to line filaments. Unlike in the case of constant amplitude helical solutions, the dynamics are much more complicated for the decaying helical waves, owing to the fact that the rate of decay of the helical perturbations along the vortex filament is not constant in time. We give an analytical and numerical description of the motion of decaying helical Kelvin waves, from which we are able to ascertain the influence of the physical parameters on the decay, translational motion along the filament, and rotational motion, of these waves (all of which depend nonlinearly on time). One interesting finding is that the helical Kelvin waves do not decay uniformly. Rather, such waves decay slowly for small time scales, and more rapidly for large time scales. The rotational and translational velocity of the Kelvin waves depend strongly on this rate of decay, and we find that the speed of propagation of a helical Kelvin wave along a quantum filament is large for small time while the wave asymptotically slows as it decays. The rotational velocity of such Kelvin waves along the filament will increase over time, asymptotically reaching a finite value. These decaying Kelvin waves correspond to wave number below the critical value for the Donnelly-Glaberson instability, and hence our results on the Schwarz quantum LIA correspond exactly to what one would expect from prior work on the Donnelly-Glaberson instability.
Measurement of the antineutrino neutral-current elastic differential cross section
Aguilar-Arevalo, A. ?A.; Brown, B. ?C.; Bugel, L.; Cheng, G.; Church, E. ?D.; Conrad, J. ?M.; Dharmapalan, R.; Djurcic, Z.; Finley, D. ?A.; Ford, R.; Garcia, F. ?G.; Garvey, G. ?T.; Grange, J.; Huelsnitz, W.; Ignarra, C.; Imlay, R.; Johnson, R. ?A.; Karagiorgi, G.; Katori, T.; Kobilarcik, T.; Louis, W. ?C.; Mariani, C.; Marsh, W.; Mills, G. ?B.; Mirabal, J.; Moore, C. ?D.; Mousseau, J.; Nienaber, P.; Osmanov, B.; Pavlovic, Z.; Perevalov, D.; Polly, C. ?C.; Ray, H.; Roe, B. ?P.; Russell, A. ?D.; Shaevitz, M. ?H.; Spitz, J.; Stancu, I.; Tayloe, R.; Van de Water, R. ?G.; Wascko, M. ?O.; White, D. ?H.; Wickremasinghe, D. ?A.; Zeller, G. ?P.; Zimmerman, E. ?D.
2015-01-01T23:59:59.000Z
We report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (d?_{?-barN??-barN}/dQ^{2}) on CH_{2} by the MiniBooNE experiment using the largest sample of antineutrino neutral current elastic candidate events ever collected. The ratio of the antineutrino to neutrino neutral current elastic scattering cross sections and a ratio of the antineutrino neutral current elastic to antineutrino charged current quasi elastic cross sections are also presented.
Nonlinear elasticity of composite networks of stiff biopolymers with flexible linkers
C. P. Broedersz; C. Storm; F. C. MacKintosh
2008-10-19T23:59:59.000Z
Motivated by recent experiments showing nonlinear elasticity of in vitro networks of the biopolymer actin cross-linked with filamin, we present an effective medium theory of flexibly cross-linked stiff polymer networks. We model such networks by randomly oriented elastic rods connected by flexible connectors to a surrounding elastic continuum, which self-consistently represents the behavior of the rest of the network. This model yields a crossover from a linear elastic regime to a highly nonlinear elastic regime that stiffens in a way quantitatively consistent with experiment.
Poroelastic modeling of fracture-seismic wave interaction
Nakagawa, Seiji
2008-08-15T23:59:59.000Z
Rock containing a compliant, fluid-filled fracture can be viewed as one case of heterogeneous poroelastic media. When this fracture is subjected to seismic waves, a strong contrast in the elastic stiffness between the fracture itself and the background can result in enhanced grain-scale local fluid flow. Because this flow--relaxing the pressure building up within the fracture--can increase the dynamic compliance of the fracture and change energy dissipation (attenuation), the scattering of seismic waves can be enhanced. Previously, for a flat, infinite fracture, we derived poroelastic seismic boundary conditions that describe the relationship between a finite jump in the stress and displacement across a fracture, expressed as a function of the stress and displacement at the boundaries. In this paper, we use these boundary conditions to determine frequency-dependent seismic wave transmission and reflection coefficients. Fluid-filled fractures with a range of mechanical and hydraulic properties are examined. From parametric studies, we found that the hydraulic permeability of a fracture fully saturated with water has little impact on seismic wave scattering. In contrast, the seismic response of a partially water-saturated fracture and a heterogeneous fracture filled with compliant liquid (e.g., supercritical CO{sub 2}) depended on the fracture permeability.
Broader source: Energy.gov (indexed) [DOE]
Water Power Peer Review WindWaveFloat Alla Weinstein Principle Power, Inc. aweinstein@principlepowerinc.com November 1, 2011 2 | Wind and Water Power Program eere.energy.gov...
Cavaleri, Luigi; Bidlot, Jean-Raymond
2015-01-01T23:59:59.000Z
We consider the effect of rain on wind wave generation and dissipation. Rain falling on a wavy surface may have a marked tendency to dampen the shorter waves in the tail of the spectrum, the related range increasing with the rain rate. Following the coupling between meteorological and wave models, we derive that on the whole this should imply stronger wind and higher waves in the most energetic part of the spectrum. This is supported by numerical experiments. However, a verification based on the comparison between operational model results and measured data suggests that the opposite is true. This leads to a keen analysis of the overall process, in particular on the role of the tail of the spectrum in modulating the wind input and the white-capping. We suggest that the relationship between white-capping and generation by wind is deeper and more implicative than presently generally assumed.
Hietala, V.M.; Vawter, G.A.
1993-12-14T23:59:59.000Z
The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size. 4 figures.
Halliday, David Fraser
2009-01-01T23:59:59.000Z
This thesis concerns the application of seismic interferometry to surface waves. Seismic interferometry is the process by which the wavefield between two recording locations is estimated, resulting in new recordings at ...
Kim, Seoktae
2006-04-12T23:59:59.000Z
New millimeter wave interferometric, multifunctional sensors have been studied for industrial sensing applications: displacement measurement, liquid-level gauging and velocimetry. Two types of configuration were investigated to implement the sensor...
Bush, John W. M.
Yves Couder, Emmanuel Fort, and coworkers recently discovered that a millimetric droplet sustained on the surface of a vibrating fluid bath may self-propel through a resonant interaction with its own wave field. This article ...
S. P. Wells; T. Averett; D. Barkhuff; D. H. Beck; E. J. Beise; C. Benson; H. Breuer; R. Carr; S. Covrig; J. DelCorso; G. Dodson; C. Eppstein; M. Farkhondeh; B. W. Filippone; T. Forest; P. Frasier; R. Hasty; T. M. Ito; C. Jones; W. Korsch; S. Kowalski; P. Lee; E. Maneva; K. McCarty; R. D. McKeown; J. Mikell; B. Mueller; P. Naik; M. L. Pitt; J. Ritter; V. Savu; D. T. Spayde; M. Sullivan; R. Tieulent; E. Tsentalovich; B. Yang; T. Zwart
2000-02-22T23:59:59.000Z
We report the first measurement of the vector analyzing power in inclusive transversely polarized elastic electron-proton scattering at Q^2 = 0.1 (GeV/c)^2 and large scattering angles. This quantity should vanish in the single virtual photon exchange, plane wave impulse approximation for this reaction, and can therefore provide information on double photon exchange amplitudes for electromagnetic interactions with hadronic systems. We find a non-zero value of A=-15.4+/-5.4 ppm. No calculations of this observable for nuclei other than spin 0 have been carried out in these kinematics, and the calculation using the spin orbit interaction from a charged point nucleus of spin 0 cannot describe these data.
Ibraeva, E. T., E-mail: ibr@inp.k [National Nuclear Center of the Republic of Kazakhstan, Institute for Nuclear Physics (Kazakhstan); Zhusupov, M. A.; Imambekov, O.; Sagindykov, Sh. Sh. [Al Farabi Kazakh National University (Kazakhstan)
2008-07-15T23:59:59.000Z
The differential cross sections for elastic proton scattering on the unstable neutron-rich nuclei {sup 8}Li and {sup 9}Li at E = 700 and 60 MeV per nucleon were considered. The {sup 8}Li nucleus was treated on the basis of the three-body {alpha}-t-n model, while the {sup 9}Li nucleus was considered within the {alpha}-t-n and {sup 7}Li-n-n models. The cross sections in question were calculated within Glauber diffraction theory. A comparison of the results with available experimental data made it possible to draw conclusions on the quality of the wave functions and potential used in the calculations.
Rate-dependent elastic hysteresis during the peeling of Pressure Sensitive Adhesives
Richard Villey; Costantino Creton; Pierre-Philippe Cortet; Marie-Julie Dalbe; Thomas Jet; Baudouin Saintyves; Stéphane Santucci; Loïc Vanel; David Yarusso; Matteo Ciccotti
2015-05-20T23:59:59.000Z
The modelling of the adherence energy during peeling of Pressure Sensitive Adhesives (PSA) has received much attention since the 1950's, uncovering several factors that aim at explaining their high adherence on most substrates, such as the softness and strong viscoelastic behaviour of the adhesive, the low thickness of the adhesive layer and its confinement by a rigid backing. The more recent investigation of adhesives by probe-tack methods also revealed the importance of cavitation and stringing mechanisms during debonding, underlining the influence of large deformations and of the related non-linear response of the material, which also intervenes during peeling. Although a global modelling of the complex coupling of all these ingredients remains a formidable issue, we report here some key experiments and modelling arguments that should constitute an important step forward. We first measure a non-trivial dependence of the adherence energy on the loading geometry, namely through the influence of the peeling angle, which is found to be separable from the peeling velocity dependence. This is the first time to our knowledge that such adherence energy dependence on the peeling angle is systematically investigated and unambiguously demonstrated. Secondly, we reveal an independent strong influence of the large strain rheology of the adhesives on the adherence energy. We complete both measurements with a microscopic investigation of the debonding region. We discuss existing modellings in light of these measurements and of recent soft material mechanics arguments, to show that the adherence energy during peeling of PSA should not be associated to the propagation of an interfacial stress singularity. The relevant deformation mechanisms are actually located over the whole adhesive thickness, and the adherence energy during peeling of PSA should rather be associated to the energy loss by viscous friction and by rate-dependent elastic hysteresis.
MAGNETOHYDRODYNAMIC SHALLOW WATER WAVES: LINEAR ANALYSIS
Heng, Kevin [Institute for Advanced Study, School of Natural Sciences, Einstein Drive, Princeton, NJ 08540 (United States); Spitkovsky, Anatoly, E-mail: heng@ias.ed, E-mail: anatoly@astro.princeton.ed [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States)
2009-10-01T23:59:59.000Z
We present a linear analysis of inviscid, incompressible, magnetohydrodynamic (MHD) shallow water systems. In spherical geometry, a generic property of such systems is the existence of five wave modes. Three of them (two magneto-Poincare modes and one magneto-Rossby mode) are previously known. The other two wave modes are strongly influenced by the magnetic field and rotation, and have substantially lower angular frequencies; as such, we term them 'magnetostrophic modes'. We obtain analytical functions for the velocity, height, and magnetic field perturbations in the limit that the magnitude of the MHD analogue of Lamb's parameter is large. On a sphere, the magnetostrophic modes reside near the poles, while the other modes are equatorially confined. Magnetostrophic modes may be an ingredient in explaining the frequency drifts observed in Type I X-ray bursts from neutron stars.
Plane wave holonomies in loop quantum gravity II: sine wave solution
Donald E. Neville
2014-11-10T23:59:59.000Z
This paper constructs an approximate sinusoidal wave packet solution to the equations of loop quantum gravity (LQG). There is an SU(2) holonomy on each edge of the LQG simplex, and the goal is to study the behavior of these holonomies under the influence of a passing gravitational wave. The equations are solved in a small sine approximation: holonomies are expanded in powers of sines, and terms beyond $\\sin^2$ are dropped; also, fields vary slowly from vertex to vertex. The wave is unidirectional and linearly polarized. The Hilbert space is spanned by a set of coherent states tailored to the symmetry of the plane wave case. Fixing the spatial diffeomorphisms is equivalent to fixing the spatial interval between vertices of the loop quantum gravity lattice. This spacing can be chosen such that the eigenvalues of the triad operators are large, as required in the small sine limit, even though the holonomies are not large. Appendices compute the energy of the wave, estimate the lifetime of the coherent state packet, discuss coarse-graining, and determine the behavior of the spinors used in the U(N) SHO realization of LQG.
Flow of Navier-Stokes Fluids in Cylindrical Elastic Tubes
Sochi, Taha
2013-01-01T23:59:59.000Z
Analytical expressions correlating the volumetric flow rate to the inlet and outlet pressures are derived for the time-independent flow of Newtonian fluids in cylindrically-shaped elastic tubes using a one-dimensional Navier-Stokes flow model with two pressure-area constitutive relations. These expressions for elastic tubes are the equivalent of Poiseuille and Poiseuille-type expressions for rigid tubes which were previously derived for the flow of Newtonian and non-Newtonian fluids under various flow conditions. Formulae and procedures for identifying the pressure field and tube geometric profile are also presented. The results are validated by a finite element method implementation. Sensible trends in the analytical and numerical results are observed and documented.
Elastic properties of Pu metal and Pu-Ga alloys
Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A
2010-01-05T23:59:59.000Z
We present elastic properties, theoretical and experimental, of Pu metal and Pu-Ga ({delta}) alloys together with ab initio equilibrium equation-of-state for these systems. For the theoretical treatment we employ density-functional theory in conjunction with spin-orbit coupling and orbital polarization for the metal and coherent-potential approximation for the alloys. Pu and Pu-Ga alloys are also investigated experimentally using resonant ultrasound spectroscopy. We show that orbital correlations become more important proceeding from {alpha} {yields} {beta} {yields} {gamma} plutonium, thus suggesting increasing f-electron correlation (localization). For the {delta}-Pu-Ga alloys we find a softening with larger Ga content, i.e., atomic volume, bulk modulus, and elastic constants, suggest a weakened chemical bonding with addition of Ga. Our measurements confirm qualitatively the theory but uncertainties remain when comparing the model with experiments.
Atomic picture of elastic deformation in a metallic glass
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Wang, X. D.; Aryal, S.; Zhong, C.; Ching, W. Y.; Sheng, H. W.; Zhang, H.; Zhang, D. X.; Cao, Q. P.; Jiang, J. Z.
2015-03-17T23:59:59.000Z
The tensile behavior of a Ni??Nb?? metallic glass (MG) has been studied by using ab initio density functional theory (DFT) calculation with a large cell containing 1024 atoms (614 Ni and 410 Nb). We provide insight into how a super elastic limit can be achieved in a MG. Spatially inhomogeneous responses of single atoms and also major polyhedra are found to change greatly with increasing external stress when the strain is over 2%, causing the intrinsically viscoelastic behavior. We uncover the origin of the observed super elastic strain limit under tension (including linear and viscoelastic strains) in small-sized MG samples,more »mainly caused by inhomogeneous distribution of excess volumes in the form of newly formed subatomic cavities.« less
Surface tension and contact with soft elastic solids
Robert W. Style; Callen Hyland; Rostislav Boltyanskiy; John S. Wettlaufer; Eric R. Dufresne
2013-10-11T23:59:59.000Z
Johnson-Kendall-Robert (JKR) theory is the basis of modern contact mechanics. It describes how two deformable objects adhere together, driven by adhesion energy and opposed by elasticity. However, it does not include solid surface tension, which also opposes adhesion by acting to flatten the surface of soft solids. We tested JKR theory to see if solid surface tension affects indentation behaviour. Using confocal microscopy, we characterised the indentation of glass particles into soft, silicone substrates. While JKR theory held for particles larger than a critical, elastocapillary lengthscale, it failed for smaller particles. Instead, adhesion of small particles mimicked the adsorption of particles at a fluid interface, with a size-independent contact angle between the undeformed surface and the particle given by a generalised version of Young's law. A simple theory quantitatively captures this behaviour, and explains how solid surface tension dominates elasticity for small-scale indentation of soft materials.
Autoresonant Excitation of Diocotron Waves
Wurtele, Jonathan
of the wave, the pump and the wave will phase lock at very low wave amplitude. When the pump reachesAutoresonant Excitation of Diocotron Waves J. Fajans E. Gilson U.C. Berkeley L. Friedland Hebrew of phase with the oscillator, and the os- cillator's amplitude will decrease, eventually reaching zero
Elastic Coulomb-levitation: why is ice so slippery?
Chang Q. Sun
2015-02-14T23:59:59.000Z
The elastic, less dense, polarized, and thermally stable supersolid skin lubricates ice. Molecular undercoordination shortens the H-O bond and lengthens the O:H nonbond through O-O repulsion, which is associated with low-frequency and high-magnitude of O:H vibration and a dual O-O polarization. The softer O:H springs attached with stronger molecular dipoles provide forces levitating objects sliding on ice, like Maglev or Hovercraft.
Surface effects in the crystallization process of elastic flexible polymers
Stefan Schnabel; Thomas Vogel; Michael Bachmann; Wolfhard Janke
2010-02-10T23:59:59.000Z
Investigating thermodynamic properties of liquid-solid transitions of flexible homopolymers with elastic bonds by means of multicanonical Monte Carlo simulations, we find crystalline conformations that resemble ground-state structures of Lennard-Jones clusters. This allows us to set up a structural classification scheme for finite-length flexible polymers and their freezing mechanism in analogy to atomic cluster formation. Crystals of polymers with "magic length" turn out to be perfectly icosahedral.
Systematic analysis of Persson's contact mechanics theory of randomly rough elastic surfaces
Wolf B. Dapp; Nikolay Prodanov; Martin H. Müser
2014-06-24T23:59:59.000Z
We systematically check explicit and implicit assumptions of Persson's contact mechanics theory. It casts the evolution of the pressure distribution ${\\rm Pr}(p)$ with increasing resolution of surface roughness as a diffusive process, in which resolution plays the role of time. The tested key assumptions of the theory are: (a) the diffusion coefficient is independent of pressure $p$, (b) the diffusion process is drift-free at any value of $p$, (c) the point $p=0$ acts as an absorbing barrier, i.e., once a point falls out of contact, it never reenters again, (d) the Fourier component of the elastic energy is only populated if the appropriate wave vector is resolved, and (e) it no longer changes when even smaller wavelengths are resolved. Using high-resolution numerical simulations, we quantify deviations from these approximations and find quite significant discrepancies in some cases. For example, the drift becomes substantial for small values of $p$, which typically represent points in real space close to a contact line. On the other hand, there is a significant flux of points reentering contact. These and other identified deviations cancel each other to a large degree, resulting in an overall excellent description for contact area, contact geometry, and gap distribution functions. Similar fortuitous error cancellations cannot be guaranteed under different circumstances, for instance when investigating rubber friction. The results of the simulations may provide guidelines for a systematic improvement of the theory.
Overall Dynamic Properties of 3-D periodic elastic composites
Ankit Srivastava; Sia Nemat-Nasser
2011-05-27T23:59:59.000Z
A method for the homogenization of 3-D periodic elastic composites is presented. It allows for the evaluation of the averaged overall frequency dependent dynamic material constitutive tensors relating the averaged dynamic ?eld variable tensors of velocity, strain, stress, and linear momentum. The formulation is based on micromechanical modeling of a representative unit cell of a composite proposed by Nemat-Nasser & Hori (1993), Nemat-Nasser et. al. (1982) and Mura (1987) and is the 3-D generalization of the 1-D elastodynamic homogenization scheme presented by Nemat-Nasser & Srivastava (2011). We show that for 3-D periodic composites the overall compliance (stiffness) tensor is hermitian, irrespective of whether the corresponding unit cell is geometrically or materially symmetric.Overall mass density is shown to be a tensor and, like the overall compliance tensor, always hermitian. The average strain and linear momentum tensors are, however, coupled and the coupling tensors are shown to be each others' hermitian transpose. Finally we present a numerical example of a 3-D periodic composite composed of elastic cubes periodically distributed in an elastic matrix. The presented results corroborate the predictions of the theoretical treatment.
Studying the Proton "Radius" Puzzle with ?p Elastic Scattering
R. Gilman; E. J. Downie; G. Ron; A. Afanasev; J. Arrington; O. Ates; F. Benmokhtar; J. Bernauer; E. Brash; W. J. Briscoe; K. Deiters; J. Diefenbach; C. Djalali; B. Dongwi; L. El Fassi; S. Gilad; K. Gnanvo; R. Gothe; D. Higinbotham; R. Holt; Y. Ilieva; H. Jiang; M. Kohl; G. Kumbartzki; J. Lichtenstadt; A. Liyanage; N. Liyanage; M. Meziane; Z. -E. Meziani; D. G. Middleton; P. Monaghan; K. E. Myers; C. Perdrisat; E. Piasetzsky; V. Punjabi; R. Ransome; D. Reggiani; P. Reimer; A. Richter; A. Sarty; E. Schulte; Y. Shamai; N. Sparveris; S. Strauch; V. Sulkosky; A. S. Tadepalli; M. Taragin; L. Weinstein
2013-07-29T23:59:59.000Z
The Proton Radius Puzzle is the inconsistency between the proton radius determined from muonic hydrogen and the proton radius determined from atomic hydrogen level transitions and ep elastic scattering. No generally accepted resolution to the Puzzle has been found. Possible solutions generally fall into one of three categories: the two radii are different due to novel beyond-standard-model physics, the two radii are different due to novel aspects of nucleon structure, and the two radii are the same, but there are underestimated uncertainties or other issues in the ep experiments. The MUon proton Scattering Experiment (MUSE) at the Paul Scherrer Institut is a simultaneous measurement of \\mu^+ p and e^+ p elastic scattering, as well as \\mu^- p and e^- p elastic scattering, which will allow a determination of the consistency of the \\mu p and the ep interactions. The differences between + and - charge scattering are sensitive to two-photon exchange effects, higher-order corrections to the scattering process. The slopes of the cross sections as Q^2 -> 0 determine the proton "radius". We plan to measure relative cross sections at a typical level of a few tenths of a percent, which should allow the proton radius to be determined at the level of ~0.01 fm, similar to previous ep measurements. The measurements will test several possible explanations of the proton radius puzzle, including some models of beyond-standard-model physics, some models of novel hadronic physics, and some issues in the radius extraction from scattering data.
The contact of elastic regular wavy surfaces revisited
Vladislav A. Yastrebov; Guillaume Anciaux Jean-Francois Molinari
2014-09-05T23:59:59.000Z
We revisit the classic problem of an elastic solid with a two-dimensional wavy surface squeezed against an elastic flat half-space from infinitesimal to full contact. Through extensive numerical calculations and analytic derivations, we discover previously overlooked transition regimes. These are seen in particular in the evolution with applied load of the contact area and perimeter, the mean pressure and the probability density of contact pressure. These transitions are correlated with the contact area shape, which is affected by long range elastic interactions. Our analysis has implications for general random rough surfaces, as similar local transitions occur continuously at detached areas or coalescing contact zones. We show that the probability density of null contact pressures is non-zero at full contact. This might suggest revisiting the conditions necessary for applying Persson's model at partial contacts and guide the comparisons with numerical simulations. We also address the evaluation of the contact perimeter for discrete geometries and the applicability of Westergaard's solution for three-dimensional geometries.
Quantization of Perturbations in an Inflating Elastic Solid
Michael Sitwell; Kris Sigurdson
2014-07-01T23:59:59.000Z
A sufficiently rigid relativistic elastic solid can be stable for negative pressure values and thus is capable of driving a stage of accelerated expansion. If a relativistic elastic solid drove an inflationary stage in the early Universe, quantum mechanically excited perturbations would arise in the medium. We quantize the linear scalar and tensor perturbations and investigate the observational consequences of having such an inflationary period. We find that slowly varying sound speeds of the perturbations and a slowing varying equation of state of the solid can produce a slightly red-tilted scalar power spectrum that agrees with current observational data. Even in the absence of nonadiabatic pressures, perturbations evolve on superhorizon scales, due to the shear stresses within the solid. As such, the spectra of perturbations are in general sensitive to the details of the end of inflation and we characterize this dependence. Interestingly, we uncover here accelerating solutions for elastic solids with (1 + P/\\rho) significantly greater than 0 that nevertheless have nearly scale-invariant scalar and tensor spectra. Beyond theoretical interest, this may allow for the possibility of viable inflationary phenomenology relatively far from the de Sitter regime.
'Elastic' fluctuation-induced effects in smectic wetting films
Pikina, E. S., E-mail: elena@ogri.r [Russian Academy of Sciences, Oil and Gas Research Institute (Russian Federation)
2009-11-15T23:59:59.000Z
The Li-Kardar field theory approach is generalized to wetting smectic films and the 'elastic' fluctuation-induced interaction is obtained between the external flat bounding surface and distorted IA (isotropic liquid-smectic A) interface acting as an 'internal' (bulk) boundary of the wetting smectic film under the assumption that the IA interface is essentially 'softer' than the surface smectic layer. This field theory approach allows calculating the fluctuation-induced corrections in Hamiltonians of the so-called 'correlated' liquids confined by two surfaces, in the case where one of the bounding surfaces is 'rough' and with different types of surface smectic layer anchoring. We obtain that in practice, the account of thermal displacements of the smectic layers in a wetting smectic film reduces to the addition of two contributions to the IA interface Hamiltonian. The first, so-called local contribution describes the long-range thermal 'elastic' repulsion of the fluctuating IA interface from the flat bounding surface. The second, so-called nonlocal contribution is connected with the occurrence of an 'elastic' fluctuation-induced correction to the stiffness of the IA interface. An analytic expression for this correction is obtained.
Holographic p-wave superconductor models with Weyl corrections
Zhang, Lu; Jing, Jiliang
2015-01-01T23:59:59.000Z
We study the effect of the Weyl corrections on the holographic p-wave dual models in the backgrounds of AdS soliton and AdS black hole via a Maxwell complex vector field model by using the numerical and analytical methods. We find that, in the soliton background, the Weyl corrections do not influence the properties of the holographic p-wave insulator/superconductor phase transition, which is different from that of the Yang-Mills theory. However, in the black hole background, we observe that similar to the Weyl correction effects in the Yang-Mills theory, the higher Weyl corrections make it easier for the p-wave metal/superconductor phase transition to be triggered, which shows that these two p-wave models with Weyl corrections share some similar features for the condensation of the vector operator.
Lo, W.-C.; Sposito, G.; Majer, E.
2007-02-01T23:59:59.000Z
An analytical theory is presented for the low-frequency behavior of dilatational waves propagating through a homogeneous elastic porous medium containing two immiscible fluids. The theory is based on the Berryman-Thigpen-Chin (BTC) model, in which capillary pressure effects are neglected. We show that the BTC model equations in the frequency domain can be transformed, at sufficiently low frequencies, into a dissipative wave equation (telegraph equation) and a propagating wave equation in the time domain. These partial differential equations describe two independent modes of dilatational wave motion that are analogous to the Biot fast and slow compressional waves in a single-fluid system. The equations can be solved analytically under a variety of initial and boundary conditions. The stipulation of 'low frequency' underlying the derivation of our equations in the time domain is shown to require that the excitation frequency of wave motions be much smaller than a critical frequency. This frequency is shown to be the inverse of an intrinsic time scale that depends on an effective kinematic shear viscosity of the interstitial fluids and the intrinsic permeability of the porous medium. Numerical calculations indicate that the critical frequency in both unconsolidated and consolidated materials containing water and a nonaqueous phase liquid ranges typically from kHz to MHz. Thus engineering problems involving the dynamic response of an unsaturated porous medium to low excitation frequencies (e.g. seismic wave stimulation) should be accurately modeled by our equations after suitable initial and boundary conditions are imposed.
Concentration of near-inertial waves in anticyclones: an energetic argument
Danioux, Eric; Bühler, Oliver
2015-01-01T23:59:59.000Z
An overlooked conservation law for near-inertial waves propagating in a background flow provides a new perspective on the concentration of these waves in regions of anticyclonic vorticity. The conservation law implies that this concentration is a direct consequence of the decrease in spatial scales and associated increase in potential energy experienced by an initially homogeneous wave field. Scaling arguments and numerical simulations of a reduced-gravity model of mixed-layer near-inertial waves confirm this interpretation and elucidate the influence of the strength of the background flow relative to the dispersion.
Marsh, S.P.
1988-03-08T23:59:59.000Z
An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 4 figs.
Marsh, S.P.
1987-03-12T23:59:59.000Z
An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 3 figs., 3 tabs.
Travis Norsen; Damiano Marian; Xavier Oriols
2014-10-14T23:59:59.000Z
The ontology of Bohmian mechanics includes both the universal wave function (living in 3N-dimensional configuration space) and particles (living in ordinary 3-dimensional physical space). Proposals for understanding the physical significance of the wave function in this theory have included the idea of regarding it as a physically-real field in its 3N-dimensional space, as well as the idea of regarding it as a law of nature. Here we introduce and explore a third possibility in which the configuration space wave function is simply eliminated -- replaced by a set of single-particle pilot-wave fields living in ordinary physical space. Such a re-formulation of the Bohmian pilot-wave theory can exactly reproduce the statistical predictions of ordinary quantum theory. But this comes at the rather high ontological price of introducing an infinite network of interacting potential fields (living in 3-dimensional space) which influence the particles' motion through the pilot-wave fields. We thus introduce an alternative approach which aims at achieving empirical adequacy (like that enjoyed by GRW type theories) with a more modest ontological complexity, and provide some preliminary evidence for optimism regarding the (once popular but prematurely-abandoned) program of trying to replace the (philosophically puzzling) configuration space wave function with a (totally unproblematic) set of fields in ordinary physical space.
Graham, T. B.
2010-04-01T23:59:59.000Z
The IR Hot Wave{trademark} furnace is a breakthrough heat treatment system for manufacturing metal components. Near-infrared (IR) radiant energy combines with IR convective heating for heat treating. Heat treatment is an essential process in the manufacture of most components. The controlled heating and cooling of a metal or metal alloy alters its physical, mechanical, and sometimes chemical properties without changing the object's shape. The IR Hot Wave{trademark} furnace offers the simplest, quickest, most efficient, and cost-effective heat treatment option for metals and metal alloys. Compared with other heat treatment alternatives, the IR Hot Wave{trademark} system: (1) is 3 to 15 times faster; (2) is 2 to 3 times more energy efficient; (3) is 20% to 50% more cost-effective; (4) has a {+-}1 C thermal profile compared to a {+-}10 C thermal profile for conventional gas furnaces; and (5) has a 25% to 50% smaller footprint.
Lucas, Timothy S. (4614 River Mill Ct., Glen Allen, VA 23060)
1991-01-01T23:59:59.000Z
A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.
Yerganian, Simon Scott (Lee's Summit, MO)
2003-02-11T23:59:59.000Z
A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase-shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in the direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.
Yerganian, Simon Scott (Lee's Summit, MO)
2001-07-17T23:59:59.000Z
A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.
Viscosity and Riemann solutions On the Influence of Viscosity on
Canic, Suncica
Viscosity and Riemann solutions On the Influence of Viscosity on Riemann Solutions SunÅ¸cica Å¸ Cani and uniqueness of Riemann solutions are affected by the precise form of viscosity which is used to select shock on viscosity and distinguish between Lax shock waves with and without a profile. These bifurcations
Adaptive multiconfigurational wave functions
Evangelista, Francesco A., E-mail: francesco.evangelista@emory.edu [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)
2014-03-28T23:59:59.000Z
A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff ?. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than ?. The resulting ?-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (?+SD-CI), which is based on a small ?-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build ?-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The ?-CI and ?+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the ?-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the ?-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.
Real-time Water Waves with Wave Particles
Yuksel, Cem
2010-10-12T23:59:59.000Z
This dissertation describes the wave particles technique for simulating water surface waves and two way fluid-object interactions for real-time applications, such as video games. Water exists in various different forms in our environment...
Propagation of seismic waves through liquefied soils
Taiebat, Mahdi; Jeremic, Boris; Dafalias, Yannis; Kaynia, Amir; Cheng, Zhao
2010-01-01T23:59:59.000Z
the mechanisms of wave propagation and ARTICLE IN PRESS M.Numerical analysis Wave propagation Earthquake Liquefactionenergy during any wave propagation. This paper summarizes
California Small Hydropower and Ocean Wave Energy
California Small Hydropower and Ocean Wave Energy Resources IN SUPPORT OF THE 2005 INTEGRATED....................................................................................................................... 9 Ocean Wave Energy............................................................................................................. 20 Wave Energy Conversion Technology
mm-Wave Phase Shifters and Switches
Adabi Firouzjaei, Ehsan
2010-01-01T23:59:59.000Z
4.1.1 Slow wave transmissioncombiners . . . . . . . . . . . 5.3 mm-Wave implementationfailed to predict current mm-wave design trend [1] . . . . .
Heat Waves, Global Warming, and Mitigation
Carlson, Ann E.
2008-01-01T23:59:59.000Z
Heat Waves, Global Warming, and Mitigation Ann E. Carlson*2008]HEAT WAVES, GLOBAL WARMING, AND MITIGATION 175 stroke2001). 2008]HEAT WAVES, GLOBAL WARMING, AND MITIGATION 177
Sirmas, Nick
2015-01-01T23:59:59.000Z
Previous experiments have revealed that shock waves driven through dissipative gases may become unstable, for example, in granular gases, and in molecular gases undergoing strong relaxation effects. The mechanisms controlling these instabilities are not well understood. We successfully isolated and investigated this instability in the canonical problem of piston driven shock waves propagating into a medium characterized by inelastic collision processes. We treat the standard model of granular gases, where particle collisions are taken as inelastic with constant coefficient of restitution. The inelasticity is activated for sufficiently strong collisions. Molecular dynamic simulations were performed for 30,000 particles. We find that all shock waves investigated become unstable, with density non-uniformities forming in the relaxation region. The wavelength of these fingers is found comparable to the characteristic relaxation thickness. Shock Hugoniot curves for both elastic and inelastic collisions were obtaine...
Incrocci, Thomas Paul
1970-01-01T23:59:59.000Z
. . . . . . . . , . . . ~ . ~ INTRODUCTION BACKGROUND TO THE PROBLEM Theory of Mountain Waves Mountain Waves and Clear Air Turbulence (CAT). Page iv v vi viii The Vertical Propagation and Transfer of Energy of Mountain Waves into the Stratosphere The Influence of Wind... and the prevailing wind directions favorable for the development of extensive mountain wave activity in the surrounding areas (Wind directions taken from Harrison and Sowa, 1966). 24 Nid-tropospheric conditions for 1200 GNT on 19 March 1966 28 Nid...
Li, Yan.
1990-10-08T23:59:59.000Z
Ultrasonic techniques have recently been applied to the texture characterization in polycrystalline aggregates of hexagonal crystals. The basis of this application lies in the relations between the elastic constants {bar C}{sub ij} of the aggregates, which can be inferred from ultrasonic wave velocity measurements, and the orientation distribution coefficients. This communication present such relations for aggregates which possess orthotopic material symmetry and hexagonal crystal symmetry for Voigt, Reuss, and Hill averaging methods in a unified and concise representation.
Wave refraction and wave energy on Cayo Arenas
Walsh, Donald Eugene
1962-01-01T23:59:59.000Z
WAVE REFRACTION AND WAVE ENERGY ON CAYO ARENAS A Thesis By Donald E. Welsh Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... January 1962 Major Subject: Physical Oceanography WAVE REFRACTION AND WAVE ENERGY ON CAYO ARENAS A Thesis Donald E. Walsh Approved as to style and content by: Chairman of the Committee ead of Department ' / January 1962 ACKNOWLEDGMENTS...
Phase stability and elastic properties of Cr-V alloys
Gao, M. C.; Suzuki, Y.; Schweiger, H.; Do?an, Ö.N.; Hawk, J.; Widom M.
2013-02-20T23:59:59.000Z
V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and elastic properties of Cr–V binary alloys. The cluster expansion study reveals the formation of various ordered compounds at low temperatures that were not previously known. These compounds become unstable due to the configurational entropy of bcc solid solution as the temperature is increased. The elastic constants of ordered and disordered compounds are calculated at both T = 0 K and finite temperatures. The overall trends in elastic properties are in agreement with measurements using the resonant ultrasound spectroscopy method. The calculations predict that addition of V to Cr decreases both the bulk modulus and the shear modulus, and enhances the Poisson’s ratio, in agreement with experiments. Decrease in the bulk modulus is correlated to decrease in the valence electron density and increase in the lattice constant. An enhanced Poisson’s ratio for bcc Cr–V alloys (compared to pure Cr) is associated with an increased density of states at the Fermi level. Furthermore, the difference charge density in the bonding region in the (110) slip plane is highest for pure Cr and decreases gradually as V is added. The present calculation also predicts a negative Cauchy pressure for pure Cr, and it becomes positive upon alloying with V. The intrinsic ductilizing effect from V may contribute, at least partially, to the experimentally observed ductilizing phenomenon in the literature.
Application of elastic-plastic fracture mechanics to marine structures
Pathi, Amarkumar
1991-01-01T23:59:59.000Z
, as it was not possible to measure yield strength directly from the high rate tensile tests: Cryc(dynamic) ~ CTTa(dynacaic) Cryc(ciaiic) CTTc(cCaiic) (IV. 8) The basic algorithm for predicting CTOD consists of integrating (IV. 9) where B is the crack front length... OF SCIENCE May 1991 Major Subject: Mechanical Engineering APPLICATION OF ELASTIC-PLASTIC FRACTURE MECHANICS TO MARINE STRUCTURES A Thesis by AMARI&UMAR PATEII Approved as to style and content by: Ted L. Anderson (C 'r of Commi e) Ravind ona ember...
np elastic spin transfer measurements at 788 MeV
McNaughton, M. W.; Koch, K.; Supek, I.; Tanaka, N.; McNaughton, K. H.; Riley, P. J.; Ambrose, DA; Johnson, J. D.; Smith, A.; Glass, G.; Hiebert, John C.; Northcliffe, L. C.; Simon, A. J.; Adams, D. L.; Ransome, R. D.; Clayton, D. B.; Spinka, H. M.; Jepperson, R. H.; Tripard, G. E.
1991-01-01T23:59:59.000Z
PHYSICAL REVIEW C VOLUME 44, NUMBER 6 DECEMBER 1991 ARTICLES np elastic spin transfer measurements at 788 MeV M. W. McNaughton, K. Koch, I. Supek, and N. Tanaka Los Alamos National Laboratory, Los Alamos, New Mexico 87545 K. H. McNaughton, P. J... radius of about 3 rnm and centered on the 25-cm-thick liquid-deuterium (LD2) neutron-production target. B. Neutron beam magnets (LBBM6,7). The neutrons passed through the fringe fields of these magnets and were precessed about 50' from L spin. A...
Nonlinear elastic free energies and gradient Young-Gibbs measures
Roman Kotecký; Stephan Luckhaus
2012-06-26T23:59:59.000Z
We investigate, in a fairly general setting, the limit of large volume equilibrium Gibbs measures for elasticity type Hamiltonians with clamped boundary conditions. The existence of a quasiconvex free energy, forming the large deviations rate functional, is shown using a new interpolation lemma for partition functions. The local behaviour of the Gibbs measures can be parametrized by Young measures on the space of gradient Gibbs measures. In view of unboundedness of the state space, the crucial tool here is an exponential tightness estimate that holds for a vast class of potentials and the construction of suitable compact sets of gradient Gibbs measures.
Elastic Moduli Inheritance and Weakest Link in Bulk Metallic Glasses
Stoica, Alexandru Dan [ORNL; Wang, Xun-Li [ORNL; Lu, Z.P. [University of Science and Technology, Beijing; Clausen, Bjorn [Los Alamos National Laboratory (LANL); Brown, Donald [Los Alamos National Laboratory (LANL)
2012-01-01T23:59:59.000Z
We show that a variety of bulk metallic glasses (BMGs) inherit their Young s modulus and shear modulus from the solvent components. This is attributed to preferential straining of locally solvent-rich configurations among tightly bonded atomic clusters, which constitute the weakest link in an amorphous structure. This aspect of inhomogeneous deformation, also revealed by our in-situ neutron diffraction studies of an elastically deformed BMG, suggests a scenario of rubber-like viscoelasticity owing to a hierarchy of atomic bonds in BMGs.
Elastic contribution to interaction of vortices in uniaxial superconductors
Kogan, Vladimir [Ames Laboratory, DOE; Department of Physics, Iowa State University, Ames, Iowa
2013-10-24T23:59:59.000Z
The stress caused by vortices in tetragonal superconductors contributes to the intervortex interaction which depends on vortex orientation within the crystal, on elastic moduli, and is attractive within certain angular regions even in fields along the c crystal axis. For sufficiently strong stress dependence of the critical temperature, this contribution may result in distortions of the hexagonal vortex lattice for H||c. In small fields it leads to formation of a square vortex lattice with a fixed H independent spacing. This should be seen in the magnetization M(H) as a discontinuous jump of magnetization at the transition from the Meissner to mixed states.
Quasi-Elastic Scattering Measurements Morgan Wascko Imperial College London
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible forPortsmouth/Paducah47,193.70COMMUNITY AEROSOL:QuantumAprilElastic Scattering
Wilson, R.K.; Reuter, R.C. Jr.
1982-03-01T23:59:59.000Z
In previous studies of the mechanical behavior of line focusing solar collectors, the reflective surface panel was modeled as a thin, initially flat, elastic plate that underwent large displacements to attain the shape of a prescribed parabolic cylinder. Attention was focused upon the stresses that developed in an adhesive layer which bonded the deformed panel to a rigid, parabolic substructure. Among the myriad possible collector designs, some possess longitudinally oriented, hollow ribs or corrugations in the substructure which interrupt the transverse continuity of the bond line between the deformed panel and the substructure. Thus, finite gaps in the adhesive are present which create regions where the panel surface becomes intermittently supported. The presence of these gaps perturbs the otherwise smooth distribution of adhesive contact stresses and it is the analytical modeling of this behavior that is the subject of the present report. In particular, attention is devoted to gaps which overlap with the edge effect zone - a region near the rim or vertex of the deformed panel where, in the absence of uniform edge loads necessary to maintain a true parabolic shape, high stresses and associated deformations occur. Significant influences of the gap size and position in the edge effect zone are demonstrated and discussed.
Observations of the high frequency range of the wave spectrum
Prevosto, M. [IFREMER, Plouzane (France); Krogstad, H.E. [SINTEF Industrial Mathematics, Trondheim (Norway); Barstow, S. [OCEANOR, Trondheim (Norway); Guedes Soares, C. [Technical Univ. of Lisbon, Lisboa (Portugal)
1995-12-31T23:59:59.000Z
This paper takes a new look at the high frequency range of the wave spectrum. The analysis is based on data sets from two recent field campaigns offshore Portugal and Crete carried out in the MAST II WAVEMOD project, data from the WADIC experiment in the North Sea, and deep sea data from Haltenbanken and Voeringplataaet offshore Norway. In addition, the authors also show spectra obtained by spectral inversion of ERS-1 SAR imagery. The influence and calibration of wave measuring instrumentation and the use of wavenumber spectra when comparing spectra from shallow water is emphasized.
Menikoff, Ralph [Los Alamos National Laboratory
2012-04-03T23:59:59.000Z
Shock initiation in a plastic-bonded explosives (PBX) is due to hot spots. Current reactive burn models are based, at least heuristically, on the ignition and growth concept. The ignition phase occurs when a small localized region of high temperature (or hot spot) burns on a fast time scale. This is followed by a growth phase in which a reactive front spreads out from the hot spot. Propagating reactive fronts are deflagration waves. A key question is the deflagration speed in a PBX compressed and heated by a shock wave that generated the hot spot. Here, the ODEs for a steady deflagration wave profile in a compressible fluid are derived, along with the needed thermodynamic quantities of realistic equations of state corresponding to the reactants and products of a PBX. The properties of the wave profile equations are analyzed and an algorithm is derived for computing the deflagration speed. As an illustrative example, the algorithm is applied to compute the deflagration speed in shock compressed PBX 9501 as a function of shock pressure. The calculated deflagration speed, even at the CJ pressure, is low compared to the detonation speed. The implication of this are briefly discussed.
Rossen I. Ivanov
2007-07-12T23:59:59.000Z
The Euler's equations describe the motion of inviscid fluid. In the case of shallow water, when a perturbative asymtotic expansion of the Euler's equations is taken (to a certain order of smallness of the scale parameters), relations to certain integrable equations emerge. Some recent results concerning the use of integrable equation in modeling the motion of shallow water waves are reviewed in this contribution.
Magnetohydrodynamic Shearing Waves
Bryan M. Johnson
2007-02-12T23:59:59.000Z
I consider the nonaxisymmetric linear theory of a rotating, isothermal magnetohydrodynamic (MHD) shear flow. The analysis is performed in the shearing box, a local model of a thin disk, using a decomposition in terms of shearing waves, i.e., plane waves in a frame comoving with the shear. These waves do not have a definite frequency as in a normal mode decomposition, and numerical integration of a coupled set of amplitude equations is required to characterize their time dependence. Their generic time dependence, however, is oscillatory with slowly-varying frequency and amplitude, and one can construct accurate analytical solutions by applying the Wentzel-Kramers-Brillouin method to the full set of amplitude equations. The solutions have the following properties: 1) Their accuracy increases with wavenumber, so that most perturbations that fit within the disk are well-approximated as modes with time-dependent frequencies and amplitudes. 2) They can be broadly classed as incompressive and compressive perturbations, the former including the nonaxisymmetric extension of magnetorotationally unstable modes, and the latter being the extension of fast and slow modes to a differentially-rotating medium. 3) Wave action is conserved, implying that their energy varies with frequency. 4) Their shear stress is proportional to the slope of their frequency, so that they transport angular momentum outward (inward) when their frequency increases (decreases). The complete set of solutions constitutes a comprehensive linear test suite for numerical MHD algorithms that incorporate a background shear flow. I conclude with a brief discussion of possible astrophysical applications.
Elastic Properties of Rolled Uranium -- 10 wt.% Molybdenum Nuclear Fuel Foils
D. W. Brown; D. J. Alexander; K. D. Clarke; B. Clausen; M. A. Okuniewski; T. A. Sisneros
2013-11-01T23:59:59.000Z
In situ neutron diffraction data was collected during elastic loading of rolled foils of uranium-10 wt.% molybdenum bonded to a thin layer of zirconium. Lattice parameters were ascertained from the diffraction patterns to determine the elastic strain and, subsequently, the elastic moduli and Poisson’s ratio in the rolling and transverse directions. The foil was found to be elastically isotropic in the rolling plane with an effective modulus of 86 + / - 3 GPa and a Poisson’s ratio 0.39 + / - 0.04.
Elastic constants determined by nanoindentation for p-type thermoelectric half-Heusler
Gahlawat, S.; Wheeler, L.; White, K. W., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); He, R.; Chen, S.; Ren, Z. F., E-mail: zren@uh.edu, E-mail: kwwhite@uh.edu [Department of Physics and TcSUH, University of Houston, Houston, Texas 77204 (United States)
2014-08-28T23:59:59.000Z
This paper presents a study of the elastic properties of the p-type thermoelectric half-Heusler material, Hf{sub 0.44}Zr{sub 0.44}Ti{sub 0.12}CoSb{sub 0.8}Sn{sub 0.2}, using nanoindentation. Large grain-sized polycrystalline specimens were fabricated for these measurements, providing sufficient indentation targets within single grains. Electron Backscatter Diffraction methods indexed the target grains for the correlation needed for our elastic analysis of individual single crystals for this cubic thermoelectric material. Elastic properties, including the Zener ratio and the Poisson ratio, obtained from the elasticity tensor are also reported.
Elastic Constants of Ni-Mn-Ga Magnetic Shape Memory Alloys
Stipcich, M. [Universitat de Barcelona; Manosa, L. [Universitat de Barcelona; Planes, A. [Universitat de Barcelona; Morin, M. [INSA de Lyon; Zarestky, Jerel L [ORNL; Lograsso, Tom [Ames Laboratory; Stassis, C. [Ames Laboratory
2004-01-01T23:59:59.000Z
We have measured the adiabatic second order elastic constants of two Ni-Mn-Ga magnetic shape memory crystals with different martensitic transition temperatures, using ultrasonic methods. The temperature dependence of the elastic constants has been followed across the ferromagnetic transition and down to the martensitic transition temperature. Within experimental errors no noticeable change in any of the elastic constants has been observed at the Curie point. The temperature dependence of the shear elastic constant C' has been found to be very different for the two alloys. Such a different behavior is in agreement with recent theoretical predictions for systems undergoing multi-stage structural transitions.
A Numerical Algorithm for Single Phase Fluid Flow in Elastic Porous Media
Ewing, Richard E.
, petroleum, and environmental engineering for several decades. While considering the impact of the rock algorithm. KEYWORDS: geomechanics, uid ow, elastic deformation, porous media 1 Introduction Mechanical
Wave Propagation in Jointed Geologic Media
Antoun, T
2009-12-17T23:59:59.000Z
Predictive modeling capabilities for wave propagation in a jointed geologic media remain a modern day scientific frontier. In part this is due to a lack of comprehensive understanding of the complex physical processes associated with the transient response of geologic material, and in part it is due to numerical challenges that prohibit accurate representation of the heterogeneities that influence the material response. Constitutive models whose properties are determined from laboratory experiments on intact samples have been shown to over-predict the free field environment in large scale field experiments. Current methodologies for deriving in situ properties from laboratory measured properties are based on empirical equations derived for static geomechanical applications involving loads of lower intensity and much longer durations than those encountered in applications of interest involving wave propagation. These methodologies are not validated for dynamic applications, and they do not account for anisotropic behavior stemming from direcitonal effects associated with the orientation of joint sets in realistic geologies. Recent advances in modeling capabilities coupled with modern high performance computing platforms enable physics-based simulations of jointed geologic media with unprecedented details, offering a prospect for significant advances in the state of the art. This report provides a brief overview of these modern computational approaches, discusses their advantages and limitations, and attempts to formulate an integrated framework leading to the development of predictive modeling capabilities for wave propagation in jointed and fractured geologic materials.
Electron Bernstein Wave Studies in MST
Seltzman, Andrew H.; Anderson, Jay K.; Nonn, Paul D.; Kauffold, Jason X.; Forest, Cary B. [University of Wisconsin-Madison, Dept. Of Physics, 1150 University Ave., Madison, WI 53706 (United States); Diem, Stephanie J. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States)
2011-12-23T23:59:59.000Z
The overdense plasma in an RFP prevents electromagnetic waves from propagating past the edge, however use of the electron Bernstein wave (EBW) has the potential to heat and drive current in the plasma. MHD simulations have demonstrated that resistive tearing mode stability is very sensitive to gradients in the edge current density profile allowing EBW to potentially be a stabilizing influence. A new MW level experiment is being commissioned on MST to evaluate the potential use of the EBW for current profile control on the RFP. The development of new equipment includes a 5.5 GHz klystron driven by a novel switchmode power supply. A quartz window has been constructed and coupling with a cylindrical molybdenum wave guide antenna has been studied. Due to the steep edge density gradient in the RFP, it is possible to efficiently couple to the EBW with O or X mode launch. The EBW is strongly damped at the electron cyclotron resonance where it couples to the electron gyromotion and alters the electron distribution. Either Fisch-Boozer or Ohkawa current drive mechanisms can be activated to drive off axis current in the plasma. Preliminary experiments have been performed to verify high power coupling and understand heating via observed x-ray emission when compared to Fokker-Plank modeling in CQL3D.
Martin, R. W.; Sathish, S. [University of Dayton Research Institute, Structural Integrity Division 300 College Park Drive, Dayton, OH, 45469 (United States); Blodgett, M. P. [Air Force Research Lab, RXCA, Wright Patterson AFB, OH, 45433 (United States)
2013-01-25T23:59:59.000Z
The interaction of a focused acoustic beam with materials generates Rayleigh surface waves (RSW) and surface skimming longitudinal waves (SSLW). Acoustic microscopic investigations have used the RSW amplitude and the velocity measurements, extensively for grain structure analysis. Although, the presence of SSLW has been recognized, it is rarely used in acoustic imaging. This paper presents an approach to perform microstructure imaging and local elastic modulus measurements by combining both RSW and SSLW. The acoustic imaging of grain structure was performed by measuring the amplitude of RSW and SSLW signal. The microstructure images obtained on the same region of the samples with RSW and SSLW are compared and the difference in the contrast observed is discussed based on the propagation characteristics of the individual surface waves. The velocity measurements are determined by two point defocus method. The surface wave velocities of RSW and SSLW of the same regions of the sample are combined and presented as average Young's modulus image.
CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland
Haller, Merrick
CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland ABSTRACT Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms at station 139. Keywords: wave energy, survivability, breaking waves, joint distribution, OWEC INTRODUCTION
Gas Explosion Characterization, Wave Propagation
s & Dt^boooo^j RisÃ¸-R-525 Gas Explosion Characterization, Wave Propagation (Small-Scale Experiments EXPLOSION CHARACTERIZATION, WAVE PROPAGATION (Small-Scale Experiments) G.C. Larsen Abstract. A number characteristics 14 3.5. Characteristics of the primary pressure wave 21 3.6. Pressure propagation over a hard
2, 70177025, 2014 Freaque wave
NHESSD 2, 70177025, 2014 Freaque wave occurrences in 2013 P. C. Liu Title Page Abstract to the corresponding final paper in NHESS if available. Brief Communication: Freaque wave occurrences in 2013 P. C. Liu7025, 2014 Freaque wave occurrences in 2013 P. C. Liu Title Page Abstract Introduction Conclusions References
Karney, Charles
is an envelope solitary wave. These solitary waves are not solitons. The occurrence of the constant phase pulses-state propagation of one of the two lower hybrid rays in a homogeneous considering the balance between thermal break up into two types of solitary waves, constant phase pulses or envelope pulses. e examine
Microstructural Design for Stress Wave Energy Management /
Tehranian, Aref
2013-01-01T23:59:59.000Z
Nemat-Nasser, Stress-wave energy management through materialNasser, S. , 2010. Stress-wave energy management throughconstitute pressure wave energy and/or shear wave energy.
Craig, Walter
Introduction Modeling of large ocean waves Propagation speed Coherent wavetrains Near-shore wave waves #12;Introduction Modeling of large ocean waves Propagation speed Coherent wavetrains NearMaster University Tsunamis and ocean waves #12;Introduction Modeling of large ocean waves Propagation speed Coherent
Elastic Compton Scattering from the Nucleon and Deuteron
Robert P. Hildebrandt
2005-12-20T23:59:59.000Z
Goal of this work is the consistent description of elastic Compton scattering from the single nucleon and the deuteron. The theoretical framework chosen is Chiral Perturbation Theory, which is the low-energy formulation of Quantum Chromodynamics, where we extend the spectrum of active degrees of freedom from only pions and nucleons to also the Delta(1232) resonance. In the deuteron sector, we treat the nucleon-nucleon interaction non-perturbatively. Besides the Compton cross sections, our main concern is with the nucleon polarizabilities, which are a useful tool to describe the reaction of the internal nucleonic degrees of freeedom to the external electromagnetic field. Experimentally, only a few nucleon polarizabilities are known. Especially our present knowledge of the neutron polarizabilities is not satisfying. The reason why it is so difficult to determine these quantities experimentally is the finite lifetime of the free neutron. Therefore, we want to contribute to the ongoing discussion of the neutron polarizabilities by fitting the average over proton and neutron polarizabilities to the elastic deuteron Compton-scattering data. Similarly, we determine the proton polarizabilities from fits to the single-proton Compton data. We finally combine both results in order to identify the neutron polarizabilities.
Transport of organelles by elastically coupled motor proteins
Deepak Bhat; Manoj Gopalakrishnan
2014-12-17T23:59:59.000Z
Motor-driven intracellular transport is a complex phenomenon where multiple motor proteins attached to a cargo are simultaneously engaged in pulling activity, often leading to tug-of-war and bidirectional motion. However, most mathematical and computational models ignore the details of the motor-cargo interaction. A few papers have studied more realistic models of cargo transport by including elastic motor-cargo coupling, but either restricts the number of motors and/or uses purely phenomenological forms for energy-dependent hopping rates. Here, we study a generic Model In which N motors are elastically coupled to a cargo, which itself is subject to thermal noise in the cytoplasm and an additional external applied force. The motor-hopping rates are chosen to satisfy detailed balance with respect to the energy of stretching. The master equation is converted to a linear Fokker-Planck equation (LFPE), which yields the average positions of the cargo and motors, as well as their fluctuations and correlation functions. We apply this formalism to two specific forms of the hopping rates. Analytical results are obtained for mean cargo velocity, diffusion coefficient and the average force experienced by each motor for arbitrary N, and compared with numerical simulations. The expansion procedure also allows us to quantify load-sharing features among the cargo-bound motors. In general, we observe significant deviations between analytical predictions based on LFPE and the corresponding numerical results, which suggests a prominent role for higher order corrections.
Relevance of complex branch points for partial wave analysis
Ceci, S.; Svarc, A. [Rudjer Boskovic Institute, Bijenicka 54, HR-10000 Zagreb (Croatia); Doering, M. [HISKP (Theorie), Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany); Hanhart, C.; Krewald, S. [Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany); Meissner, U.-G. [HISKP (Theorie), Universitaet Bonn, Nussallee 14-16, D-53115 Bonn (Germany); Institut fuer Kernphysik and Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Institute for Advanced Simulation, Forschungszentrum Juelich, D-52425 Juelich (Germany)
2011-07-15T23:59:59.000Z
A central issue in hadron spectroscopy is to deduce--and interpret--resonance parameters, namely, pole positions and residues, from experimental data, for those are the quantities to be compared to lattice QCD or model calculations. However, not every structure in the observables derives from a resonance pole: the origin might as well be branch points, either located on the real axis (when a new channel composed of stable particles opens) or in the complex plane (when at least one of the intermediate particles is unstable). In this paper we demonstrate first the existence of such branch points in the complex plane and then show on the example of the {pi}N P{sub 11} partial wave that it is not possible to distinguish the structures induced by the latter from a true pole signal based on elastic data alone.
Chen, Changhua; Xiao, Renzhen; Sun, Jun; Song, Zhimin; Huo, Shaofei; Bai, Xianchen; Shi, Yanchao; Liu, Guozhi [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)] [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)
2013-11-15T23:59:59.000Z
This paper provides a fresh insight into the effect of non-uniform slow wave structure (SWS) used in a relativistic backward wave oscillator (RBWO) with a resonant reflector. Compared with the uniform SWS, the reflection coefficient of the non-uniform SWS is higher, leading to a lower modulating electric field in the resonant reflector and a larger distance to maximize the modulation current. Moreover, for both types of RBWOs, stronger standing-wave field takes place at the rear part of the SWS. In addition, besides Cerenkov effects, the energy conversion process in the RBWO strongly depends on transit time effects. Thus, the matching condition between the distributions of harmonic current and standing wave field provides a profound influence on the beam-wave interaction. In the non-uniform RBWO, the region with a stronger standing wave field corresponds to a higher fundamental harmonic current distribution. Particle-in-cell simulations show that with a diode voltage of 1.02 MV and beam current of 13.2 kA, a microwave power of 4 GW has been obtained, compared to that of 3 GW in the uniform RBWO.
aggregatibacter actinomycetemcomitansarcb influences: Topics...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
was compared with that of control Paris-Sud XI, Universit de 393 INFLUENCE OF CARBON AEROGEL TEXTURE ON PEMFC PERFORMANCES Computer Technologies and Information Sciences...
L. Montagnier; J. Aissa; E. Del Giudice; C. Lavallee; A. Tedeschi; G. Vitiello
2010-12-23T23:59:59.000Z
Some bacterial and viral DNA sequences have been found to induce low frequency electromagnetic waves in high aqueous dilutions. This phenomenon appears to be triggered by the ambient electromagnetic background of very low frequency. We discuss this phenomenon in the framework of quantum field theory. A scheme able to account for the observations is proposed. The reported phenomenon could allow to develop highly sensitive detection systems for chronic bacterial and viral infections.
Candan, Abdullah [Central Research and Practice Laboratory (AH?LAB), Ahi Evran University, 40100 K?r?ehir (Turkey); U?ur, Gökay [Department of Physics, Faculty of Science, Gazi University, 06500 Ankara (Turkey)
2014-10-06T23:59:59.000Z
We have performed ab-initio calculations of the structural, electronic, elastic and dynamical properties for the spinel compounds CdX{sub 2}O{sub 4} (X=Al, Ga, In) using the plane wave pseudo-potential method within the generalized gradient approximation (GGA). The calculated lattice parameters, elastic constants for these compounds are in good agreement with the previous calculated values. The computed direct band gaps of CdAl{sub 2}O{sub 4}, CdGa{sub 2}O{sub 4} and CdIn{sub 2}O{sub 4} are 2.90 eV, 1.92 eV and 1.16 eV, respectively. The lattice vibrations were calculated by direct method. The calculated phonon dispersion curves show that all compounds are dynamically stable in the spinel structure.
PHYSICAL REVIEW E 84, 061906 (2011) Mechanics of soft composites of rods in elastic gels
MacKintosh, F.C.
PHYSICAL REVIEW E 84, 061906 (2011) Mechanics of soft composites of rods in elastic gels Moumita of composites consisting of randomly distributed stiff fibers embedded in an elastic matrix in two and three of the compressibility of the composite relative to its shear compliance as a result of the addition of stiff rodlike
ANALYSIS OF ANISOTROPY IN ELASTIC CONSTANTS OF SiCp/2124 Al METAL MATRIX COMPOSITES
Hong, Soon Hyung
ANALYSIS OF ANISOTROPY IN ELASTIC CONSTANTS OF SiCp/2124 Al METAL MATRIX COMPOSITES H.K. Jung* , Y; Metal matrix composite; Elastic constants; Aspect ratio; Anisotropy 1. Introduction Metal matrix composites (MMCs) are becoming attractive materials for advanced aerospace structures because
THESIS FOR THE DEGREE OF LICENTIATE OF PHILOSOPHY Model Adaptivity in Elasticity
Patriksson, Michael
THESIS FOR THE DEGREE OF LICENTIATE OF PHILOSOPHY Model Adaptivity in Elasticity DAVID HEINTZ, Sweden 2008 #12;Model Adaptivity in Elasticity DAVID HEINTZ Â© DAVID HEINTZ, 2008 Thesis for Licentiate List of Appended Papers The licentiate thesis consists of an introductory text to subjects and methods
Flow of Volatile-Free and Volatile-Rich Basaltic Magmas through Elastic-Walled Dikes
Al Hanbali, Ahmad
averaged in "one-dimensional" flow tube. #12;Questions: · Can we obtain a simple 1D symmetric model) · Anisotropy 1 in horizontal and vertical rock stress #12;Elastic flow equations · Continuity equation t(m bFlow of Volatile-Free and Volatile-Rich Basaltic Magmas through Elastic-Walled Dikes O. Bokhove
SHELL THEORIES ARISING AS LOW ENERGY -LIMIT OF 3D NONLINEAR ELASTICITY
Lewicka, Marta
SHELL THEORIES ARISING AS LOW ENERGY -LIMIT OF 3D NONLINEAR ELASTICITY MARTA LEWICKA, MARIA to minimizers of suitable lower dimensional limit energies. In this paper we discuss shell theories arising of -limit) of the 3d nonlinear elasticity for thin shells around an arbitrary smooth 2d surface
SHELL THEORIES ARISING AS LOW ENERGY -LIMIT OF 3D NONLINEAR ELASTICITY
SHELL THEORIES ARISING AS LOW ENERGY -LIMIT OF 3D NONLINEAR ELASTICITY By Marta Lewicka Maria that the elastic energy of defor- mations scales like h4, h being the thickness of a shell, we derive a limiting dimensional limit energies. In this paper we discuss shell theories arising as -limits of higher scalings
Thermo-visco-elasticity with rate-independent plasticity in isotropic materials undergoing
Bartels, Soeren
Thermo-visco-elasticity with rate-independent plasticity in isotropic materials undergoing thermal effects. Numerical discretization of the thermo- dynamically consistent model is proposed by implicit time. These "thermo-elastic" stresses may trigger activated inelastic processes, typically slip plastic- ity or even
Paris-Sud XI, Université de
Mechanically equivalent elastic-plastic deformations and the problem of plastic spin David J author to receive correspondence (steigman@me.berkeley.edu) Abstract: The problem of plastic spin is phrased in terms of a notion of mechanical equivalence among local relaxed configurations of an elastic/plastic
Phenomenological study of parabolic and spherical indentation of elastic-ideally plastic material
Paris-Sud XI, Université de
Phenomenological study of parabolic and spherical indentation of elastic-ideally plastic material O ideally plastic materials was carried out by using precise results of finite elements calculations behaviour is found. Two elastic-plastic regimes and two plastic regimes are observed for materials of very
Elastic-Plastic Models for Stable Crack Growtht *James R. Rice
Elastic-Plastic Models for Stable Crack Growtht by *James R. Rice Mareh 1973 'PCAbh ~ ~ e c.\\. (n do not fully recover their strain upon unloading. The idealized non-linear elastic (left) and rigid-plastic,. there is ~ strain concentration created at the cut-ahead tip in the rigid-plastic material and the deformation field
Effect of elastic strain energy on self-organized pattern formation
Pan, Ernie
Effect of elastic strain energy on self-organized pattern formation E Pan1*, R Zhu1 , and P W Chung2 1 Department of Civil Engineering, University of Akron, Akron, Ohio, USA 2 US Army Research in the calculation of the binding energy among atoms. The elastic strain energy is accurately evaluated
A nonlocal problem arising in the study of magneto-elastic interactions
Shafrir, Itai
the exchange energy Eex, the elastic energy Eel and the elastic-magnetic energy Eem. Let v be the displacement(m) + Eem(m, v) + Eel(v) We neglect here other contributions to the free energy due, for example
A New Attempt to Reconcile the Statistical and Phenomenological Theories of Rubber Elasticity
Fleming, Paul D. "Dan"
A New Attempt to Reconcile the Statistical and Phenomenological Theories of Rubber Elasticity O. H theories of rubber elasticity are re- viewed briefly. Combining recent concepts proposed by Yeoh and Gent, a new theory is proposed. The proposed constitutive model for rubber vulcanizates invokes two mech
Thermal Fluctuations and Rubber Elasticity Xiangjun Xing,1,* Paul M. Goldbart,2
Goldbart, Paul M.
Thermal Fluctuations and Rubber Elasticity Xiangjun Xing,1,* Paul M. Goldbart,2 and Leo Radzihovsky, compared to that of classical rubber elasticity. To leading order, this mechanism provides a simple on the external deformation. DOI: 10.1103/PhysRevLett.98.075502 PACS numbers: 62.20.Dc, 61.41.+e The term rubber
CONSTRUCTING AN ELASTIC TOUCH PANEL WITH EMBEDDED IR-LEDS USING SILICONE RUBBER
Tanaka, Jiro
CONSTRUCTING AN ELASTIC TOUCH PANEL WITH EMBEDDED IR-LEDS USING SILICONE RUBBER Yuichiro Sakamoto a technique for the construction of an elastic touch panel using silicone rubber. The technique is similar is made of transparent silicone rubber rather than acrylic. Moreover, we embedded infrared LEDs within
COMPARISON OF ELASTIC OF POROUS CORDIERITE BY FLEXURE AND DYNAMIC TEST METHODS
Stafford, Randall [Cummins, Inc] [Cummins, Inc; Golovin, K. B. [Cummins, Inc] [Cummins, Inc; Dickinson, A. [Cummins, Inc] [Cummins, Inc; Watkins, Thomas R [ORNL] [ORNL; Shyam, Amit [ORNL] [ORNL; Lara-Curzio, Edgar [ORNL] [ORNL
2012-01-01T23:59:59.000Z
Previous work showed differences in apparent elastic modulus between mechanical flexure testing and resonance methods. Flexure tests have been conducted using non-contact optical systems to directly measure deflection for calculation of elastic modulus. Dynamic test methods for elastic modulus measurement were conducted on the same material for comparison. The results show significant difference in the apparent elastic modulus for static flexure versus dynamic methods. The significance of the difference in apparent elastic modulus on thermal stress and the hypotheses for these differences will be discussed. Dynamic measurement (resonance) and static measurement (mechanical) produce different values for elastic modulus of porous cordierite ceramic. The elastic modulus from resonance is a measure of the material response at very low strain which is different from the material response in a mechanical test with relatively large strain. The apparent elastic moduli for dynamic versus static test methods in this study are different by a factor of two. This result has significant impact on calculated stress and life in an aftertreatment component.
Sevostianov, Igor
Elsevier B.V. All rights reserved. Keywords: Polymer matrix composites; Short-fiber composite; ElasticConnection between elastic moduli and thermal conductivities of anisotropic short fiber reinforced form 29 May 2003 Abstract Cross-property connections for two phase composites derived recently
Elastic uplift in southeast Greenland due to rapid ice mass loss Shfaqat A. Khan,1
Larson, Kristine
Elastic uplift in southeast Greenland due to rapid ice mass loss Shfaqat A. Khan,1 John Wahr,2] The rapid unloading of ice from the southeastern sector of the Greenland ice sheet between 2001 and 2006), Elastic uplift in southeast Greenland due to rapid ice mass loss, Geophys. Res. Lett., 34, L21701, doi:10
FIRST-ORDER SYSTEM LEAST SQUARES (FOSLS) FOR GEOMETRICALLY NONLINEAR ELASTICITY
McCormick, Steve
and a consti- tutive equation. The equilibrium equation and associated boundary conditions relate a balance of nonlinearity into the equations of elasticity. The constitutive equation, or material law as it is sometimes-squares (FOSLS) method to approximate the solution to the equations of geometrically nonlinear elasticity in two
Swigon, David
DNA stretching modeled at the base pair level: Overtwisting and shear instability in elastic Accepted 28 October 2011 Available online 12 November 2011 Keywords: DNA mechanics Overstretching Discrete elastic model Simplex algorithm Bifurcations a b s t r a c t Stretching experiments on single DNA
ON QUASI-ELASTIC SCATTERING OF SLOW NEUTRONS IN MOLECULAR LIQUIDS
Boyer, Edmond
L-317 ON QUASI-ELASTIC SCATTERING OF SLOW NEUTRONS IN MOLECULAR LIQUIDS M. UTSURO Research Reactor de neutrons avec élargissement par rotation moléculaire dans le liquide sont étudiés dans le cadre du du benzène liquide. Abstract. 2014 The rotational broadened quasi-elastic scattering spectrum
Elastic Lennard-Jones polymers meet clusters: Differences and similarities Stefan Schnabel,1,a
Bachmann, Michael
Elastic Lennard-Jones polymers meet clusters: Differences and similarities Stefan Schnabel,1,a of elastic flexible off-lattice polymers with Lennard-Jones monomer-monomer interaction and anharmonic and nonicosahedral low-energy polymer morphologies. © 2009 American Institute of Physics. doi:10.1063/1.3223720 I
Geophysical Prospecting, 2004, 52, 183195 Effective elastic properties of randomly fractured soils
Santos, Juan
relationships be- tween pore structure and elastic properties of porous rocks is an ongoing problem and fluids, and how they control rock properties is cru- cial to a better understanding of acousticGeophysical Prospecting, 2004, 52, 183195 Effective elastic properties of randomly fractured soils
A Performance and Cost Analysis of the Amazon Elastic Compute Cloud (EC2) Cluster Compute Instance
Bjørnstad, Ottar Nordal
A Performance and Cost Analysis of the Amazon Elastic Compute Cloud (EC2) Cluster Compute Instance the availability of Elastic Compute Cloud (EC2) Cluster Compute Instances specifically designed for high compute power available on demand the question arises if cloud computing with using and Amazon EC2 HPC
Lutchen, Kenneth
Lung and alveolar wall elastic and hysteretic behavior in rats: effects of in vivo elastase P. Ingenito, and Be´la Suki. Lung and alveolar wall elastic and hysteretic behavior in rats: effects behavior of the alveolar walls and the macroscopic mechanical properties of the whole lung in an in vivo
Analysis of the elastic behaviour of silica aerogels taken as a percolating system
Paris-Sud XI, UniversitÃ© de
289 Analysis of the elastic behaviour of silica aerogels taken as a percolating system T. Woignier of silica aerogels are performed using the three points flexural technique. The elastic behaviour is studied measurement - for silica aerogels. These highly porous materials are obtained from a sol-gel process. Solvent
A CAVITATION TRACKING METHOD FOR ELASTIC-PLASTIC FLOW IN SOLIDS
Shyue, Keh-Ming
A CAVITATION TRACKING METHOD FOR ELASTIC-PLASTIC FLOW IN SOLIDS Keh-Ming Shyue Department with cavitation. The algorithm uses a simplified model system where the behavior of the materials is modeled, and the von Mises condition for the elastic-plastic phase change. To characterize the cavitation
RESEARCH NOTE: DEFLECTION EQUATION FOR THE BUCKLING OF AN ELASTIC COLUMN
Newland, David E.
13 RESEARCH NOTE: DEFLECTION EQUATION FOR THE BUCKLING OF AN ELASTIC COLUMN SUBJECTED TO SURFACE. Introduction THE EFFECT of pressure on the buckling of elastic columns has been studied for at least the last to axial load and lateral pressure. Other authors have considered the theoretical aspects (Handelman (4
A maximum entropy-least squares estimator for elastic origin-destination trip matrix estimation
Kockelman, Kara M.
A maximum entropy-least squares estimator for elastic origin- destination trip matrix estimation propose a combined maximum entropy-least squares (ME-LS) estimator, by which O- D flows are distributed-destination trip table; elastic demand; maximum entropy; least squares; subnetwork analysis; convex combination
Loading on a vertical cylinder in multidirectional waves
Chaplin, J.R.; Subbiah, K. [City Univ., London (United Kingdom). Ocean Engineering Research Center; Irani, M. [National Research Council, Ottawa, Ontario (Canada). Institute for Marine Dynamics
1995-08-01T23:59:59.000Z
This paper presents laboratory measurements of local and total loading on an isolated vertical cylinder in irregular unidirectional and multidirectional waves. Maximum Keulegan-Carpenter numbers in individual waves were about 16, and maximum reynolds numbers about 3 {times} 10{sup 4}. It is shown that in these conditions, existing theoretical and numerical models underestimate the reduction in loading on a cylinder due to wave spreading. Besides the changes that are predicted when Morison`s equation is used with constant coefficients, there are hydrodynamic influences that contribute further force reductions. Comparisons with Dena`s (1977) hybrid approach suggest that in the present conditions these reductions are in the region of 3 and 6 percent for a spreading function cos{sup 2s} {theta}, with s = 8 and s = 2, respectively. Larger reductions can be expected at higher Keulegan-Carpenter numbers, though scale effects are likely to become more important in the drag-dominated regime.
Langasite Surface Acoustic Wave Gas Sensors: Modeling and Verification
Zheng, Peng; Greve, David W.; Oppenheim, Irving J.
2013-01-01T23:59:59.000Z
We report finite element simulations of the effect of conductive sensing layers on the surface wave velocity of langasite substrates. The simulations include both the mechanical and electrical influences of the conducting sensing layer. We show that three-dimensional simulations are necessary because of the out-of-plane displacements of the commonly used (0, 138.5, 26.7) Euler angle. Measurements of the transducer input admittance in reflective delay-line devices yield a value for the electromechanical coupling coefficient that is in good agreement with the three-dimensional simulations on bare langasite substrate. The input admittance measurements also show evidence of excitation of an additional wave mode and excess loss due to the finger resistance. The results of these simulations and measurements will be useful in the design of surface acoustic wave gas sensors.
Waves on the surface of the Orion molecular cloud
Olivier Berné; Núria Marcelino; José Cernicharo
2010-11-01T23:59:59.000Z
Massive stars influence their parental molecular cloud, and it has long been suspected that the development of hydrodynamical instabilities can compress or fragment the cloud. Identifying such instabilities has proved difficult. It has been suggested that elongated structures (such as the `pillars of creation') and other shapes arise because of instabilities, but alternative explanations are available. One key signature of an instability is a wave-like structure in the gas, which has hitherto not been seen. Here we report the presence of `waves' at the surface of the Orion molecular cloud near where massive stars are forming. The waves seem to be a Kelvin-Helmholtz instability that arises during the expansion of the nebula as gas heated and ionized by massive stars is blown over pre-existing molecular gas.
The Role of Architecture in the Elastic Response of Semiflexible Polymer and Fiber Networks
Claus Heussinger; Erwin Frey
2007-01-18T23:59:59.000Z
We study the elasticity of cross-linked networks of thermally fluctuating stiff polymers. As compared to their purely mechanical counterparts, it is shown that these thermal networks have a qualitatively different elastic response. By accounting for the entropic origin of the single-polymer elasticity, the networks acquire a strong susceptibility to polydispersity and structural randomness that is completely absent in athermal models. In extensive numerical studies we systematically vary the architecture of the networks and identify a wealth of phenomena that clearly show the strong dependence of the emergent macroscopic moduli on the underlying mesoscopic network structure. In particular, we highlight the importance of the full polymer length that to a large extent controls the elastic response of the network, surprisingly, even in parameter regions where it does not enter the macroscopic moduli explicitly. We provide theoretical scaling arguments to relate the observed macroscopic elasticity to the physical mechanisms on the microscopic and the mesoscopic scale.
Second-order diffraction forces on an array of vertical cylinders in bichromatic bidirectional waves
Vazquez, J.H. [Lamar Univ., Beaumont, TX (United States). Dept. of Civil Engineering; Williams, A.N. [Univ. of Houston, TX (United States). Dept. of Civil and Environmental Engineering
1995-02-01T23:59:59.000Z
A complete second-order solution is presented for the hydrodynamic forces due to the action of bichromatic, bidirectional waves on an array of bottom-mounted, surface-piercing cylinders of arbitrary cross section in water of uniform finite depth. Based on the constant structural cross section, the first-order problem is solved utilizing a two-dimensional Green function approach, while an assisting radiation potential approach is used to obtain the hydrodynamic loads due to the second-order potential. Results are presented which illustrate the influence of wave directionality on the second-order sum and difference frequency hydrodynamic forces on a two-cylinder array. It is found that wave directionality may have a significant influence on the second-order hydrodynamic forces on these arrays and that the assumption of unidirectional waves does not always lead to conservative estimates of the second-order loading.
Mao, Chunliu
2012-02-14T23:59:59.000Z
The adhesive contact problems of a conical frustum punch indenting a transversely isotropic elastic half space and an orthotropic elastic half space are analytically studied in this thesis work. To solve the problem involving a transversely...
Overall Dynamic Constitutive Relations of Micro-structured Elastic Composites
Sia Nemat-Nasser; Ankit Srivastava
2011-05-25T23:59:59.000Z
A method for homogenization of a heterogeneous (finite or periodic) elastic composite is presented. It allows direct, consistent, and accurate evaluation of the averaged overall frequency-dependent dynamic material constitutive relations. It is shown that when the spatial variation of the field variables is restricted by a Bloch-form (Floquet-form) periodicity, then these relations together with the overall conservation and kinematical equations accurately yield the displacement or stress modeshapes and, necessarily, the dispersion relations. It also gives as a matter of course point-wise solution of the elasto-dynamic field equations, to any desired degree of accuracy. The resulting overall dynamic constitutive relations however, are general and need not be restricted by the Bloch-form periodicity. The formulation is based on micro-mechanical modeling of a representative unit cell of the composite proposed by Nemat-Nasser and coworkers; see, e.g., [1] and [2].
Complex Rheology of Nematogenic Fluid; Connection to Elastic Turbulence
Rituparno Mandal; Buddhapriya Chakrabarti; Debarshini Chakraborti; Chandan Dasgupta
2014-06-10T23:59:59.000Z
We numerically analyse the full non-linear hydrodynamic equations of a sheared nematic fluid under shear stress and strain rate controlled situations incorporating spatial heterogeneity in the gradient direction. For a certain range of imposed stress and strain rates, this extended dynamical system shows signatures of spatio-temporal chaos and transient shear banding. In the chaotic regime the power spectra of the order parameter stress and the total injected power shows power law behavior and the total injected power shows a non-Gaussian, skewed probability distribution, which bear striking resemblance to elastic turbulence phenomena observed in polymer solutions. The scaling behavior is independent of the choice of shear rate/stress control method.
Asymptotic behavior of an elastic satellite with internal friction
Emanuele Haus; Dario Bambusi
2012-12-04T23:59:59.000Z
We study the dynamics of an elastic body whose shape and position evolve due to the gravitational forces exerted by a pointlike planet. The main result is that, if all the deformations of the satellite dissipate some energy, then under a suitable nondegeneracy condition there are only three possible outcomes for the dynamics: (i) the orbit of the satellite is unbounded, (ii) the satellite falls on the planet, (iii) the satellite is captured in synchronous resonance i.e. its orbit is asymptotic to a motion in which the barycenter moves on a circular orbit, and the satellite moves rigidly, always showing the same face to the planet. The result is obtained by making use of LaSalle's invariance principle and by a careful kinematic analysis showing that energy stops dissipating only on synchronous orbits. We also use in quite an extensive way the fact that conservative elastodynamics is a Hamiltonian system invariant under the action of the rotation group.
Elastic scattering of Beryllium isotopes near the Coulomb barrier
Di Pietro, A.; Figuera, P. [INFN-Laboratori Nazionali del Sud, Catania (Italy); Amorini, F.; Fisichella, M.; Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Randisi, G.; Rizzo, F.; Santonocito, D.; Scalia, G.; Scuderi, V.; Strano, E.; Torresi, D. [Dipartimento di Fisica ed Astronomia Universita di Catania, Catania (Italy); INFN-Laboratori Nazionali del Sud, Catania (Italy); Papa, M. [INFN-Sezione di Catania, Catania (Italy); Acosta, L.; Martel, I.; Perez-Bernal, F. [Departamento de Fisica Aplicada Universidad de Huelva, Huelva (Spain); Borge, M. J. G.; Tengblad, O. [Instituto de Estructura de la Materia CSIC, Madrid (Spain)
2011-10-28T23:59:59.000Z
In this contribution, results of experiments performed with the three Beryllium isotopes {sup 9,10,11}Be on a medium mass {sup 64}Zn target, at a center of mass energy of {approx_equal}1.4 the Coulomb barrier, will be discussed. Elastic scattering angular distributions have been measured for the {sup 9,10}Be reactions. In the {sup 11}Be case the quasielastic scattering angular distribution was obtained. In the halo nucleus case, the angular distribution exhibit a non-Fresnel-type pattern with a strong damping of the Coulomb-nuclear interference peak. Moreover, it is found that the total reaction cross-section for the halo nucleus induced collision is more than double the ones extracted in the collisions induced by the non-halo Beryllium isotopes. A large contribution to the total-reaction cross-section in the {sup 11}Be case could be attributed to transfer and/or break-up events.
Noise-assisted Thouless pump in elastically deformable molecular junctions
C. A. Perroni; F. Romeo; A. Nocera; V. Marigliano Ramaglia; R. Citro; V. Cataudella
2014-04-16T23:59:59.000Z
We study a Thouless pump realized with an elastically \\textit{deformable quantum dot} whose center of mass follows a non-linear stochastic dynamics. The interplay of noise, non-linear effects, dissipation and interaction with an external time-dependent driving on the pumped charge is fully analyzed. The results show that the quantum pumping mechanism not only is not destroyed by the force fluctuations, but it becomes stronger when the forcing signal frequency is tuned close to the resonance of the vibrational mode. The robustness of the quantum pump with temperature is also investigated and an exponential decay of the pumped charge is found when the coupling to the vibrational mode is present. Implications of our results for nano-electromechanical systems are also discussed.
Flavor decomposition of the elastic nucleon electromagnetic form factors
C.D. Cates, C.W. Jager, S. Riordan, B. Wojtsekhowski
2011-06-01T23:59:59.000Z
The u- and d-quark contributions to the elastic nucleon electromagnetic form factors have been determined using experimental data on GEn , GMn , GpE , and GpM . Such a flavor separation of the form factors became possible up to 3.4 GeV2 with recent data on GEn from Hall A at JLab. At a negative four-momentum transfer squared Q2 above 1 GeV2, for both the u- and d-quark components, the ratio of the Pauli form factor to the Dirac form factor, F2/F1, was found to be almost constant, and for each of F2 and F1 individually, the d-quark component drops continuously with increasing Q2.
Bifurcations in the optimal elastic foundation for a buckling column
Rayneau-Kirkhope, Daniel; Ding, K; Mao, Yong
2010-01-01T23:59:59.000Z
We investigate the buckling under compression of a slender beam with a distributed lateral elastic support, for which there is an associated cost. For a given cost, we study the optimal choice of support to protect against Euler buckling. We show that with only weak lateral support, the optimum distribution is a delta-function at the centre of the beam. When more support is allowed, we find numerically that the optimal distribution undergoes a series of bifurcations. We obtain analytical expressions for the buckling load around the first bifurcation point and corresponding expansions for the optimal position of support. Our theoretical predictions, including the critical exponent of the bifurcation, are confirmed by computer simulations.
Micromachinable Leaky Wave Air Transducers
Khuri-Yakub, Butrus T. "Pierre"
reflection coefficient can also in a thin plate as a meam of efficient coupling of ultrasonic energy to air of the ultrasonic energy is a function of the elastic properties of the plate andmost dominantly determinedby lowerleak rates as compared to silicon and aluminum. Since these thin dates aremuch easier to fabricate wine
Nondestructive testing using stress waves: wave propagation in layered media
Ortega, Jose Alberto
2013-02-22T23:59:59.000Z
NONDESTRUCTIVE TESTING USING STRESS WAVES: WAVE PROPAGATION IN LAYERED MEDIA A Senior Honors Thesis by JOSE ALBERTO ORTEGA Submitted to the Office of Honors Program & Academic Scholarships Texas A&M University in partial fulfillment... of the requirement of the UNIVERSITY UNDERGRADUATE RESEARCH FELLOWS April 2002 Group: Engineering NONDESTRUCTIVE TESTING USI WAVE PROPAGATION IN LA A Senior Honors The ~pe -C JOSE ALBERTO ORTI /CI Submitted to the Office of Honors Program k. Academic...
Time domain analysis of a gyrotron traveling wave amplifier with misaligned electron beam
Wang, Qiushi, E-mail: qiushiwork@gmail.com; Peng, Shuyuan [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China); University of Chinese Academy of Sciences, Beijing 100039 (China); Luo, Jirun [Institute of Electronics, Chinese Academy of Sciences, P.O. Box 2652, Beijing 100080 (China)
2014-08-15T23:59:59.000Z
This article develops a time-domain theory to study the beam-wave interaction in gyrotron traveling wave amplifier (gyro-TWA) with a misaligned electron beam. The effects of beam misalignment on the TE{sub 01} mode gyro-TWA operating at the fundamental are discussed. Numerical results show that the effect of misalignment is less obvious when the input power is larger, and the influences of misalignment on the stable gain and the stable time are basically opposite.
Sunandan Gangopadhyay; Anirban Saha
2012-04-02T23:59:59.000Z
We consider the dynamics of a charged particle interacting with background electromagnetic field under the influence of linearized gravitational waves in the long wave-length and low-velocity limit. Following the prescription in \\cite{speli}, the system is quantized and the Hamiltonian is then solved by using standard algebraic iterative methods. The solution is in conformity with the classical analysis and shows the possibility of tuning the frequency by changing the magnetic field to set up resonance.
Burq, J P; Chevallier, M; Denisov, A S; Ekelöf, T J C; Fay, F; Grafström, P; Gustafsson, L; Hagberg, E; Ille, B; Kashchuk, A P; Kulikov, A V; Lambert, M; Martin, J P; Maury, S; Querrou, M; Schegelsky, V A; Tkach, I I; Verbeken, M; Vorobyov, A A
1982-01-01T23:59:59.000Z
Experimental results on pp forward elastic scattering and the possibility of universal shrinkage of the hadronic diffraction cone
Guided Wave Propagation in Tubular Section with Multi-Layered Viscoelastic Coating
Kuo, Chi-Wei 1982-
2012-11-16T23:59:59.000Z
cross-section of the pipe. The layer between radii r1 and r2 is elastic. The outer layer between radii r2 and r3 is the viscoelastic coating material. The axial direction of the cylinder is along the z-axis. The circumferential direction is defined... by the ?-axis. Fig. 2.1 Pipe model Fig. 2.2 Pipe cross-section 2.1. Longitudinal Wave along Axial Direction The Lame-Navier equation of motion for isotropic materials is 2 2 2( ) ( ) ( / )? ? ? ?? + + ? ?? = ? ? tu u u (2.1) r3 r2 r1...
S-wave K- pi+ system in D+ ---> K- pi+ pi+ decays from Fermilab E791
Meadows, B.T.; /Cincinnati U.
2005-06-01T23:59:59.000Z
A new approach to the analysis of three body decays is presented. Model-independent results are obtained for the S-wave K{pi} amplitude as a function of K{pi} invariant mass. These are compared with results from K{sup -}{pi}{sup +} elastic scattering, and the prediction of the Watson theorem, that the phase behavior be the same below K{eta}' threshold, is tested. Contributions from I = 1/2 and I = 3/2 are not resolved in this study. If I = 1/2 dominates, however, the Watson theorem does not describe these data well.
Boyer, Edmond
Trade performances and the estimation of price-elasticities: Quality matters+ By Matthieu Crozet : Traditional trade models ignoring the dimension of product quality generally lead to excessively low trade price elasticities. In this paper, we show that higher estimated trade price elasticities, more
Brown, Michael F.
Bilayers Studied by Quasi-elastic Neutron Scattering Emil Endress, Helmut Heller,§ He´le`ne CasaltaVised Manuscript ReceiVed June 27, 2002 ABSTRACT: Quasi-elastic neutron scattering (QENS) was employed to study of motion within the bilayer on the molecular dynamics time scale. In a recent quasi-elastic neutron
Jackson, Jennifer M.
2005-01-01T23:59:59.000Z
for determining the elastic moduli at high temperatures, using both electric resistive heating (to 1800 K) and CO2 by Elsevier Ltd. Keywords: Spectroscopy; Mechanical properties; High-temperature elasticity measurements by Brillouin scattering 1. Introduction Knowledge of the high-temperature elastic properties is fundamental
Frank G. Borg; Ismo Hakala; Jukka Määttälä
2007-12-24T23:59:59.000Z
We present a summary of the basic properties of the radio wave generation, propagation and reception, with a special attention to the gigahertz bandwidth region which is of interest for wireless sensor networks. We also present some measurement results which use the so-called RSSI indicator in order to track how the field strength varies with position and distance of the transceivers. We hope the paper may be useful to anyone who looks for a quick review of the fundamentals of electromagnetic theory with application to antennas.
Lipscombe, O. J. [University of Tennessee, Knoxville (UTK); Chen, G. F. [The Institute of Physics, Chinese Academy of Sciences; Fang, Chen [Purdue University; Perring, T. G. [ISIS Facility, Rutherford Appleton Laboratory; Abernathy, Douglas L [ORNL; Christianson, Andrew D [ORNL; Egami, Takeshi [ORNL; Wang, Nanlin [The Institute of Physics, Chinese Academy of Sciences; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)
2011-01-01T23:59:59.000Z
We use neutron scattering to show that spin waves in the iron chalcogenide Fe{sub 1.05}Te display novel dispersion clearly different from both the first principles density functional calculations and recent observations in the related iron pnictide CaFe{sub 2}As{sub 2}. By fitting to a Heisenberg Hamiltonian, we find that although the nearest-neighbor exchange couplings in the two systems are quite different, their next-nearest-neighbor (NNN) couplings are similar. This suggests that superconductivity in the pnictides and chalcogenides share a common magnetic origin that is intimately associated with the NNN magnetic coupling between the irons.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron SpinPrincetonUsing Maps1DOETHE FUTURE LOOKSof Energy Wave
ccsd-00009406,version1-3Oct2005 Modeling 1-D elastic P-waves in a fractured
are modeled by hyperbolic jump conditions deduced from a nonlinear contact law used in geomechanics. Existence-Barton model [1]. This model is frequently used in geomechanics to deal with quasi-static configurations
Waves on a String We consider an elastic string, with mass per length l under constant tension
Palffy-Muhoray, Peter
= -T sin 1 (1.1) and F2y = T sin 2 (1.2) Since = (x), expanding F2y in a Taylor's series gives F2y = T sin 2 T sin 1 + T cos 1 x dx (1.3) The net force in the y-direction is Fy = F2y + F1y = T cos x dx
Waves on a String We consider an elastic string, with mass per length l under constant tension
Palffy-Muhoray, Peter
= T sin 1 (1.1) and F2y = T sin 2 (1.2) Since = (x), expanding F2y in a Taylor's series gives F2y = T sin 2 ' T sin 1 + T cos 1 @ @x dx (1.3) The net force in the y-direction is Fy = F2y + F1y = T cos @ @x
A. Isebree Moens and D.J. Korteweg: on the speed of propagation of waves in elastic tubes
Tijsseling, A.S.
OF MOENS AND KORTEWEG Contemporaneously with Thomas Young [11, 12] at the end of the 18th Century, Chladni
Tang, Wei
1996-01-01T23:59:59.000Z
) change in the "no-load" travel time. The test results indicate that the LCR ultrasonic technique can linearly track the material stress-strain behavior until the yield stress level is approached. It is applicable even in a passed yield region. The LCR...
to discern material damage. Part II: Single Mode Nonlinear Resonance Acoustic Spectroscopy. Koen E-A. Van Den: koen.vandenabeele@bwk.kuleuven.ac.be ABSTRACT: The presence of mesoscopic features and damage in quasi for non-destructive material testing has been developed and applied in the field of damage detection
M. Atiqur Rahman; M. Hossain Ali
2009-02-22T23:59:59.000Z
The transverse electromagnetic waves propagating in a relativistic two-fluid plasma influenced by the gravitational field of the Reissner-Nordstr\\"{o}m-de Sitter black hole has been investigated exploiting 3+1 split of spacetime. Reformulating the two-fluid equations, the set of simultaneous linear equations for the perturbations have been derived. Using a local approximation, the one-dimensional radial propagation of Alfv\\'{e}n and high frequency electromagnetic waves are investigated. The dispersion relation for these waves is obtained and solved numerically for the wave number.
Nonlinear Hydromagnetic Wave Support of a Stratified Molecular Cloud
T. Kudoh; S. Basu
2003-06-23T23:59:59.000Z
We perform numerical simulations of nonlinear MHD waves in a gravitationally stratified molecular cloud that is bounded by a hot and tenuous external medium. We study the relation between the strength of the turbulence and various global properties of a molecular cloud, within a 1.5-dimensional approximation. Under the influence of a driving source of Alfvenic disturbances, the cloud is lifted up by the pressure of MHD waves and reaches a steady-state characterized by oscillations about a new time-averaged equilibrium state. The nonlinear effect results in the generation of longitudinal motions and many shock waves; however, the wave kinetic energy remains predominantly in transverse, rather than longitudinal, motions. There is an approximate equipartition of energy between the transverse velocity and fluctuating magnetic field (aspredicted by small-amplitude theory) in the region of the stratified cloud which contains most of the mass; however, this relation breaks down in the outer regions, particularly near the cloud surface, where the motions have a standing-wave character. This means that the Chandrasekhar-Fermi formula applied to molecular clouds must be significantly modified in such regions. Models of an ensemble of clouds show that, for various strengths of the input energy, the velocity dispersion in the cloud $\\sigma \\propto Z^{0.5}$, where $Z$ is a characteristic size of the cloud.Furthermore, $\\sigma$ is always comparable to the mean Alfven velocity of the cloud, consistent with observational results.
Excitation of non-radial stellar oscillations by gravitational waves: a first model
D. M. Siegel; M. Roth
2010-10-17T23:59:59.000Z
The excitation of solar and solar-like g modes in non-relativistic stars by arbitrary external gravitational wave fields is studied starting from the full field equations of general relativity. We develop a formalism that yields the mean-square amplitudes and surface velocities of global normal modes excited in such a way. The isotropic elastic sphere model of a star is adopted to demonstrate this formalism and for calculative simplicity. It is shown that gravitational waves solely couple to quadrupolar spheroidal eigenmodes and that normal modes are only sensitive to the spherical component of the gravitational waves having the same azimuthal order. The mean-square amplitudes in case of stationary external gravitational waves are given by a simple expression, a product of a factor depending on the resonant properties of the star and the power spectral density of the gravitational waves' spherical accelerations. Both mean-square amplitudes and surface velocities show a characteristic R^8-dependence (effective R^2-dependence) on the radius of the star. This finding increases the relevance of this excitation mechanism in case of stars larger than the Sun.
Arbitrary amplitude ion-acoustic waves in a multicomponent plasma with superthermal species
El-Tantawy, S. A. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); Moslem, W. M. [Department of Physics, Faculty of Science, Port Said University, Port Said 42521 (Egypt); International Center for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany)
2011-11-15T23:59:59.000Z
Properties of fully nonlinear ion-acoustic waves in a multicomponent plasma consisting of warm positive ions, superthermal electrons, as well as positrons, and dust impurities have been investigated. By using the hydrodynamic model for ions and superthermal electron/positron distribution, a Sagdeev potential has been derived. Existence conditions for large amplitude solitary and shock waves are presented. In order to show that the characteristics of the solitary and shock waves are influenced by the plasma parameters, the relevant numerical analysis of the Sagdeev potential is presented. The nonlinear structures, as predicted here, may be associated with the electrostatic perturbations in interstellar medium.
Elastic Differential Cross Sections for Space Radiation Applications
Charles M. Werneth; Khin M. Maung; William P. Ford; John W. Norbury; Michael D. Vera
2014-09-15T23:59:59.000Z
The eikonal, partial wave (PW) Lippmann-Schwinger, and three-dimensional Lippmann- Schwinger (LS3D) methods are compared for nuclear reactions that are relevant for space radiation applications. Numerical convergence of the eikonal method is readily achieved when exact formulas of the optical potential are used for light nuclei (A $\\le$ 16), and the momentum-space representation of the optical potential is used for heavier nuclei. The PW solution method is known to be numerically unstable for systems that require a large number of partial waves, and, as a result, the LS3D method is employed. The effect of relativistic kinematics is studied with the PW and LS3D methods and is compared to eikonal results. It is recommended that the LS3D method be used for high energy nucleon-nucleus reactions and nucleus-nucleus reactions at all energies because of its rapid numerical convergence and stability.
Solitary and freak waves in a dusty plasma with negative ions
Abdelsalam, U. M. [Department of Mathematics, Faculty of Science, Fayoum University (Egypt); Moslem, W. M. [RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, Bochum D-44780 (Germany); Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt); Khater, A. H. [Department of Mathematics, Faculty of Science, Beni-suef University (Egypt); Shukla, P. K. [RUB International Chair, International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, Bochum D-44780 (Germany); Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 (United States)
2011-09-15T23:59:59.000Z
It is shown that solitary and freak waves can propagate in a dusty plasma composed of positive and negative ions, as well as nonextensive electrons. The evolution of the solitary waves is described by the Korteweg-de Vries (KdV) equation. However, when the frequency of the carrier wave is much smaller than the ion plasma frequency then the KdV equation is also used to study the nonlinear evolution of modulationally unstable modified ion-acoustic wavepackets through the derivation of the nonlinear Schroedinger (NLS) equation. In order to show that the characteristics of the solitary and freak waves are influenced by the plasma parameters, the relevant numerical analysis of the appropriate nonlinear solutions is presented. The relevance of the present investigation to nonlinear waves in astrophysical plasma environments is discussed.
Wave Evolution On the Evolution of Curvelets
Smith, Hart F.
Curvelets Wave Evolution On the Evolution of Curvelets by the Wave Equation Hart F. Smith of Curvelets by the Wave Equation #12;Curvelets Wave Evolution Curvelets and the Second Dyadic Decomposition Curvelets A curvelet frame {} is a wave packet frame on L2(R2) based on second dyadic decomposition. f
Wave Mechanics and the Fifth Dimension
Paul S. Wesson; James M. Overduin
2013-01-28T23:59:59.000Z
Replacing 4D Minkowski space by 5D canonical space leads to a clearer derivation of the main features of wave mechanics, including the wave function and the velocity of de Broglie waves. Recent tests of wave-particle duality could be adapted to investigate whether de Broglie waves are basically 4D or 5D in nature.
Covariance Matrix of a Double-Differential Doppler-broadened Elastic Scattering Cross Section
Arbanas, Goran [ORNL; Becker, B. [Rensselaer Polytechnic Institute (RPI); Dagan, R [Institut fur Neutronenphysik und Reaktortechnik; Dunn, Michael E [ORNL; Larson, Nancy M [ORNL; Leal, Luiz C [ORNL; Williams, Mark L [ORNL
2012-01-01T23:59:59.000Z
Legendre moments of a double-differential Doppler-broadened elastic neutron scattering cross section on {sup 238}U are computed near the 6.67 eV resonance at temperature T = 10{sup 3} K up to angular order 14. A covariance matrix of these Legendre moments is computed as a functional of the covariance matrix of the elastic scattering cross section. A variance of double-differential Doppler-broadened elastic scattering cross section is computed from the covariance of Legendre moments.