Plane wave method for elastic wave scattering by a heterogeneous...
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Plane wave method for elastic wave scattering by a heterogeneous fracture Citation Details In-Document Search Title: Plane wave method for elastic wave scattering by a ...
Nonlinear interaction of plane elastic waves
Korneev, V.A.; Nihei, K.T.; Myer, L.R.
1998-06-01
The paper presents basic first order results of nonlinear elastic theory by Murnaghan for elastic wave propagation in isotropic solids. The authors especially address the problem of resonant scattering of two collimated beams and present analytical solutions for amplitudes of all possible types of resonant interactions for elastic plane waves. For estimation of nonlinear scattered waves they use measured elastic parameters for sandstone. The most profound nonlinear effect is expected for interactions of two SH waves generating compressional P wave at sum frequency. Estimations show that nonlinear phenomena is likely to be observed in seismic data. Basic equations of nonlinear five-constant theory by Murnaghan are also presented.
Elastic wave velocity measurement combined with synchrotron X...
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Elastic wave velocity measurement combined with synchrotron X-ray measurements at high ... Title: Elastic wave velocity measurement combined with synchrotron X-ray measurements at ...
Wave propagation in anisotropic elastic materials and curvilinear...
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Wave propagation in anisotropic elastic materials and curvilinear coordinates using a summation-by-parts finite difference method Citation Details In-Document Search Title: Wave...
Elastic wave velocities in polycrystalline Mg[subscript 3]Al...
Office of Scientific and Technical Information (OSTI)
Title: Elastic wave velocities in polycrystalline Mgsubscript 3Alsubscript 2Sisubscript 3Osubscript 12-pyrope garnet to 24 GPa and 1300 K Authors: Chantel, Julien ; ...
Wave propagation in anisotropic elastic materials and curvilinear...
Office of Scientific and Technical Information (OSTI)
Journal Article: Wave propagation in anisotropic elastic materials and curvilinear coordinates using a summation-by-parts finite difference method Citation Details In-Document...
3D Elastic Seismic Wave Propagation Code
Energy Science and Technology Software Center (OSTI)
1998-09-23
E3D is capable of simulating seismic wave propagation in a 3D heterogeneous earth. Seismic waves are initiated by earthquake, explosive, and/or other sources. These waves propagate through a 3D geologic model, and are simulated as synthetic seismograms or other graphical output.
Spherical Wave Propagation in a Nonlinear Elastic Medium
Korneev, Valeri A.
2009-07-01
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.
Low-frequency elastic waves alter pore-scale colloid mobilization
Beckham, Richard Edward; Abdel-fattah, Amr I; Roberts, Peter M; Ibrahim, Reem; Tarimala, Sownitri
2009-01-01
Naturally occurring seismic events and artificially generated low-frequency elastic waves have been observed to alter the production rates of oil and water wells, sometimes increasing and sometimes decreasing production, and to influence the turbidity of water wells. TEe decreases in production are of particular concern - especially when artificially generated elastic waves are applied as a method for enhanced oil recovery. The exact conditions that result in a decrease in production remain unknown. While the underlying environment is certainly complex, the observed increase in water well turbidity after seismic events suggests the existence of a mechanism that can affect both the subsurface flow paths and mobilization of in-situ colloidal particles. This paper explores the macroscopic and microscopic effects of elastic wave stimulations on the release of colloidal particles and investigates the microscopic mechanism of particle release during stimulation. Experiments on a column packed with 1-mm borosilicate beads loaded with polystyrene microspheres demonstrate that low-frequency elastic wave stimulations enhance the mobilization of captured microspheres. Increasing the intensity of the stimulations increases the number of microspheres released and can also result in cyclical variations in effluent microsphere concentration during and after stimulations. Under a prolonged period of stimulation, the cyclical effluent variations coincided with fluctuations in the column pressure data. This behavior can be attributed to flow pathways fouling and/or rearrangements of the beads in the column. Optical microscopy observations of the beads during low frequency oscillations reveal that the individual beads rotate, thereby rubbing against each other and scraping off portions of the adsorbed microspheres. These results support the theory that mechanical interactions between soil grains are important mechanisms in flow path alteration and the mobilization of naturally
Elastic constants of, and Stonely waves in, molybdenum films measured by Brillouin scattering
Bell, J.A.; Zanoni, R.; Seaton, C.T.; Stegeman, G.I.; Makous, J.; Falco, C.M.
1988-02-22
The dispersion of Rayleigh, Stonely, and Sezawa acoustic waves guided by deposited thin molybdenum films has been used to evaluate selected elastic constants and film homogeneity. This work includes the first experimental observation of Stonely waves by Brillouin scattering.
Nonlinear interaction of plane elastic waves (Technical Report...
Office of Scientific and Technical Information (OSTI)
Office of Energy Research, Washington, DC (United States) Country of Publication: United States Language: English Subject: 58 GEOSCIENCES; POROUS MATERIALS; WAVE PROPAGATION; ...
An energy absorbing far-field boundary condition for the elastic wave equation
Petersson, N A; Sjogreen, B
2008-07-15
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.
Partial-wave analysis for elastic p{sup 13}C scattering at astrophysical energies
Dubovichenko, S. B.
2012-03-15
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.
Johnson, P.A.; McCall, K.R.; Meegan, G.D. Jr.
1993-11-01
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.
Super-Grid Modeling of the Elastic Wave Equation in Semi-Bounded Domains
Petersson, N. Anders; Sjögreen, Björn
2014-10-01
We develop a super-grid modeling technique for solving the elastic wave equation in semi-bounded two- and three-dimensional spatial domains. In this method, waves are slowed down and dissipated in sponge layers near the far-field boundaries. Mathematically, this is equivalent to a coordinate mapping that transforms a very large physical domain to a significantly smaller computational domain, where the elastic wave equation is solved numerically on a regular grid. To damp out waves that become poorly resolved because of the coordinate mapping, a high order artificial dissipation operator is added in layers near the boundaries of the computational domain. We prove by energy estimates that the super-grid modeling leads to a stable numerical method with decreasing energy, which is valid for heterogeneous material properties and a free surface boundary condition on one side of the domain. Our spatial discretization is based on a fourth order accurate finite difference method, which satisfies the principle of summation by parts. We show that the discrete energy estimate holds also when a centered finite difference stencil is combined with homogeneous Dirichlet conditions at several ghost points outside of the far-field boundaries. Therefore, the coefficients in the finite difference stencils need only be boundary modified near the free surface. This allows for improved computational efficiency and significant simplifications of the implementation of the proposed method in multi-dimensional domains. Numerical experiments in three space dimensions show that the modeling error from truncating the domain can be made very small by choosing a sufficiently wide super-grid damping layer. The numerical accuracy is first evaluated against analytical solutions of Lamb’s problem, where fourth order accuracy is observed with a sixth order artificial dissipation. We then use successive grid refinements to study the numerical accuracy in the more
Mixing of two collinear Rayleigh waves in an isotropic nonlinear elastic half-space
Morlock, Merlin B.; Kim, Jin-Yeon; Jacobs, Laurence J.; Qu, Jianmin
2014-02-18
Nonlinear mixing of two collinear, initially monochromatic, Rayleigh waves propagating in the same direction in an isotropic, nonlinear elastic solid is investigated analytically. A system of coupled ordinary differential equations is derived based on the Lagrange equations of the second kind to predict the evolution of the higher harmonic and combination frequency components of the fundamentals waves. Numerical results show that the energy transfer is larger for higher frequencies, and that the oscillation of the energy between the different frequency components depends on the amplitudes and frequencies of the fundamental waves. Furthermore, it is illustrated that the horizontal velocity component can form a shock wave while the vertical velocity component can form a pulse. The occurrence of these effects is independent of the specific fundamental frequencies and amplitudes that are mixed. However, the nonlinear interaction is more efficient when the mixing frequencies are close to each other which increases both effects. The analytical model is then extended by implementing diffraction effects in the parabolic approximation.
Partial-wave analysis of elastic {sup 4}He{sup 4}He scattering in the energy range 40-50 MeV
Dubovichenko, S. B.
2008-01-15
A partial-wave analysis of elastic {sup 4}He{sup 4}He scattering is performed in the energy range 40-50 MeV.
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-08-15
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 Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and 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 discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-04-14
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 Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and 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 discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Fu, Shubin; Gibson, Richard L.; Chung, Eric T.; Efendiev, Yalchin
2015-04-14
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 Finite-Element Method (GMsFEM) for elastic wave propagation in heterogeneous, anisotropic media, where we construct basis functions from multiple local problems for both the boundaries and interior of a coarse node support or coarse element. The application of multiscale basis functions can capture the fine scale mediummore » 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 discontinuous Galerkin formulation of the multiscale method, both of which have pros and cons. Applications of the multiscale method to three heterogeneous models show that our multiscale method can effectively model the elastic wave propagation in anisotropic media with a significant reduction in the degrees of freedom in the modeling system.« less
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Petersson, N. Anders; Sjogreen, Bjorn
2015-07-20
We develop a fourth order accurate finite difference method for solving the three-dimensional elastic wave equation in general heterogeneous anisotropic materials on curvilinear grids. The proposed method is an extension of the method for isotropic materials, previously described in the paper by Sjögreen and Petersson (2012) [11]. The method we proposed discretizes the anisotropic elastic wave equation in second order formulation, using a node centered finite difference method that satisfies the principle of summation by parts. The summation by parts technique results in a provably stable numerical method that is energy conserving. Also, we generalize and evaluate the super-grid far-fieldmore » technique for truncating unbounded domains. Unlike the commonly used perfectly matched layers (PML), the super-grid technique is stable for general anisotropic material, because it is based on a coordinate stretching combined with an artificial dissipation. Moreover, the discretization satisfies an energy estimate, proving that the numerical approximation is stable. We demonstrate by numerical experiments that sufficiently wide super-grid layers result in very small artificial reflections. Applications of the proposed method are demonstrated by three-dimensional simulations of anisotropic wave propagation in crystals.« less
Petersson, N. Anders; Sjogreen, Bjorn
2015-07-20
We develop a fourth order accurate finite difference method for solving the three-dimensional elastic wave equation in general heterogeneous anisotropic materials on curvilinear grids. The proposed method is an extension of the method for isotropic materials, previously described in the paper by Sjögreen and Petersson (2012) [11]. The method we proposed discretizes the anisotropic elastic wave equation in second order formulation, using a node centered finite difference method that satisfies the principle of summation by parts. The summation by parts technique results in a provably stable numerical method that is energy conserving. Also, we generalize and evaluate the super-grid far-field technique for truncating unbounded domains. Unlike the commonly used perfectly matched layers (PML), the super-grid technique is stable for general anisotropic material, because it is based on a coordinate stretching combined with an artificial dissipation. Moreover, the discretization satisfies an energy estimate, proving that the numerical approximation is stable. We demonstrate by numerical experiments that sufficiently wide super-grid layers result in very small artificial reflections. Applications of the proposed method are demonstrated by three-dimensional simulations of anisotropic wave propagation in crystals.
Sermeus, J.; Glorieux, C.; Sinha, R.; Vereecken, P. M.; Vanstreels, K.
2014-07-14
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 ?=421%, 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.
Cochrane, Alexander P.; Merrett, Craig G.; Hilton, Harry H.
2014-12-10
The advent of new structural concepts employing composites in primary load carrying aerospace structures in UAVs, MAVs, Boeing 787s, Airbus A380s, etc., necessitates the inclusion of flexibility as well as viscoelasticity in static structural and aero-viscoelastic analyses. Differences and similarities between aeroelasticity and aero-viscoelasticity have been investigated in [2]. An investigation is undertaken as to the dependence and sensitivity of aerodynamic and stability derivatives to elastic and viscoelastic structural flexibility and as to time dependent flight and maneuver velocities. Longitudinal, lateral and directional stabilities are investigated. It has been a well established fact that elastic lifting surfaces are subject to loss of control effectiveness and control reversal at certain flight speeds, which depend on aerodynamic, structural and material properties [5]. Such elastic analyses are extended to linear viscoelastic materials under quasi-static, dynamic, and sudden and gradual loading conditions. In elastic wings one of the critical static parameters is the velocity at which control reversal takes place (V{sub REV}{sup E}). Since elastic formulations constitute viscoelastic initial conditions, viscoelastic reversal may occur at speeds V{sub REV<}{sup ≧}V{sub REV}{sup E}, but furthermore does so in time at 0 < t{sub REV} ≤ ∞. The influence of the twin effects of viscoelastic and elastic materials and of variable flight velocities on longitudinal, lateral, directional and spin stabilities are also investigated. It has been a well established fact that elastic lifting surfaces are subject to loss of control effectiveness and control reversal at certain flight speeds, which depend on aerodynamic, structural and material properties [5]. Such elastic analyses are here extended to linear viscoelastic materials under quasi-static, dynamic, and sudden and gradual loading conditions. In elastic wings the critical parameter is the velocity at
Development of a New Stratigraphic Trap Exploration Using Elastic-Wave Seismic Technology
Bryan DeVault
2008-02-05
Vecta acquired 9 square miles of 9-C seismic data in Mountrail County, North Dakota with the Mission Canyon shoreline as a primary target. Vecta contracted the Institute Francais du Petrole in order to co-develop a more rigorous multicomponent seismic interpretation product. The final interpretation was very unique in that it utilized not only the 9-C seismic data but also the new jointly developed software. A Mission Canyon anomaly was developed in 2006; however, it was of insufficient size to be a commercial target at the time. Therefore, Vecta analyzed the shear data for anisotropy within the Bakken formation and successfully reentered an abandoned producer within the project area and drilled a horizontal leg through the anomalous zones of the middle member of the Bakken formation. The well was open hole completed, swab tested, sand fraced, and swab tested some more. No shows of oil were ever seen from the Bakken formation, but the well yielded considerable amounts of formation water. The well has been abandoned as non-commercial. From the swab tests, one may conclude considerable permeability exists in the formation, thus confirming the utility of the shear wave to detect fractures within the targeted formation.
Petersson, A
2009-01-29
The LDRD project 'A New Method for Wave Propagation in Elastic Media' developed several improvements to the traditional finite difference technique for seismic wave propagation, including a summation-by-parts discretization which is provably stable for arbitrary heterogeneous materials, an accurate treatment of non-planar topography, local mesh refinement, and stable outflow boundary conditions. This project also implemented these techniques in a parallel open source computer code called WPP, and participated in several seismic modeling efforts to simulate ground motion due to earthquakes in Northern California. This research has been documented in six individual publications which are summarized in this report. Of these publications, four are published refereed journal articles, one is an accepted refereed journal article which has not yet been published, and one is a non-refereed software manual. The report concludes with a discussion of future research directions and exit plan.
Tutuncu, A.N.; Podio, A.L.; Sharma, M.M.
1998-01-01
Uniaxial stress cycling experiments were conducted on dry, brine saturated and hexadecane saturated Berea sandstone samples to observe in detail the hysteresis in stress-strain diagrams and to understand the influence of different fluids on the strain amplitude dependence of elastic moduli and attenuation. Cycling experiments were also conducted with sandstone samples saturated with CTAB, a cationic surfactant that renders the mineral surfaces hydrophobic. Hexadecane and CTAB were selected so as to investigate the relative contributions of adhesion hysteresis and stick-slip sliding on attenuation in sedimentary granular rocks. Young`s moduli and Poisson`s ratios obtained from the cycling tests show a significant dependence on strain amplitude on dry as well as water and hexadecane saturated samples. Bow-tie-shaped diagrams are obtained when loading and unloading tangent moduli are plotted against strain. The type of fluid in the pore space and at the grain contacts has a large influence on the hysteresis observed in the stress-strain diagrams.
Sidler, Rolf, E-mail: rsidler@gmail.com [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)] [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland); Carcione, Jos M. [Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste (Italy)] [Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Borgo Grotta Gigante 42c, 34010 Sgonico, Trieste (Italy); Holliger, Klaus [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)] [Center for Research of the Terrestrial Environment, University of Lausanne, CH-1015 Lausanne (Switzerland)
2013-02-15
We present a novel numerical approach for the comprehensive, flexible, and accurate simulation of poro-elastic wave propagation in 2D polar coordinates. An important application of this method and its extensions will be the modeling of complex seismic wave phenomena in fluid-filled boreholes, which represents a major, and as of yet largely unresolved, computational problem in exploration geophysics. In view of this, we consider a numerical mesh, which can be arbitrarily heterogeneous, consisting of two or more concentric rings representing the fluid in the center and the surrounding porous medium. The spatial discretization is based on a Chebyshev expansion in the radial direction and a Fourier expansion in the azimuthal direction and a RungeKutta integration scheme for the time evolution. A domain decomposition method is used to match the fluidsolid boundary conditions based on the method of characteristics. This multi-domain approach allows for significant reductions of the number of grid points in the azimuthal direction for the inner grid domain and thus for corresponding increases of the time step and enhancements of computational efficiency. The viability and accuracy of the proposed method has been rigorously tested and verified through comparisons with analytical solutions as well as with the results obtained with a corresponding, previously published, and independently benchmarked solution for 2D Cartesian coordinates. Finally, the proposed numerical solution also satisfies the reciprocity theorem, which indicates that the inherent singularity associated with the origin of the polar coordinate system is adequately handled.
Local timespace mesh refinement for simulation of elastic wave propagation in multi-scale media
Kostin, Victor; Lisitsa, Vadim; Reshetova, Galina; Tcheverda, Vladimir
2015-01-15
This paper presents an original approach to local timespace grid refinement for the numerical simulation of wave propagation in models with localized clusters of micro-heterogeneities. The main features of the algorithm are the application of temporal and spatial refinement on two different surfaces; the use of the embedded-stencil technique for the refinement of grid step with respect to time; the use of the Fast Fourier Transform (FFT)-based interpolation to couple variables for spatial mesh refinement. The latter makes it possible to perform filtration of high spatial frequencies, which provides stability in the proposed finite-difference schemes. In the present work, the technique is implemented for the finite-difference simulation of seismic wave propagation and the interaction of such waves with fluid-filled fractures and cavities of carbonate reservoirs. However, this approach is easy to adapt and/or combine with other numerical techniques, such as finite elements, discontinuous Galerkin method, or finite volumes used for approximation of various types of linear and nonlinear hyperbolic equations.
Influence of ionization on reflection of solitary waves in a magnetized plasma
Jyoti,; Malik, Hitendra K.; Kumar, Ravinder; Dahiya, Raj P.
2013-09-15
The reflection of nonlinear solitary waves is studied in a nonuniform, magnetized plasma diffusing from an ionization source along the magnetic field lines. Contribution of the ionization term is included in the continuity equation. The behavior of solitary waves is governed by modified form of Korteweg–de Vries equation (called mKdV equation). In order to investigate the reflection of solitary waves, the mKdV equations for the right and left going waves are derived, and solved by finding new transformations coupled at the point of reflection, for obtaining the expression of reflection coefficient. Contrary to the case of usual inhomogeneous plasma, the present analysis shows that a combination of usual sech{sup 2} structure and tanh structure (called the tail of soliton) arises due to the influence of ionization term. Interestingly, this tailing structure disappears after the reflection of the soliton and hence, the soliton is downshifted prominently.
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1 Summer 2001 Heat Wave This summer has proved to be downright hot in the Southern Great ... Not only is a summer heat wave uncomfortable, but it can also be ARM Facilities Newsletter ...
Influence of voltage rise time on microwave generation in relativistic backward wave oscillator
Wu, Ping; Deng, Yuqun; Sun, Jun; Teng, Yan; Shi, Yanchao; Chen, Changhua
2015-10-15
In relativistic backward wave oscillators (RBWOs), although the slow wave structure (SWS) and electron beam determine the main characteristics of beam-wave interaction, many other factors can also significantly affect the microwave generation process. This paper investigates the influence of voltage rise time on beam-wave interaction in RBWOs. Preliminary analysis and PIC simulations demonstrate if the voltage rise time is moderately long, the microwave frequency will gradually increase during the startup process until the voltage reaches its amplitude, which can be explained by the dispersion relation. However, if the voltage rise time is long enough, the longitudinal resonance of the finitely-long SWS will force the RBWO to work with unwanted longitudinal modes for a while and then gradually hop to the wanted longitudinal mode, and this will lead to an impure microwave frequency spectrum. Besides, a longer voltage rise time will delay the startup process and thus lead to a longer microwave saturation time. And if unwanted longitudinal modes are excited due to long voltage rise time, the microwave saturation time will be further lengthened. Therefore, the voltage rise time of accelerators adopted in high power microwave technology should not be too long in case unwanted longitudinal modes are excited.
Influence of wall plasma on microwave frequency and power in relativistic backward wave oscillator
Sun, Jun; Cao, Yibing; Teng, Yan; Zhang, Yuchuan; Chen, Changhua; Wu, Ping
2015-07-15
The RF breakdown of the slow wave structure (SWS), which will lead to the generation of the wall plasma, is an important cause for pulse shortening in relativistic backward wave oscillators. Although many researchers have performed profitable studies about this issue, the influence mechanism of this factor on the microwave generation still remains not-so-clear. This paper simplifies the wall plasma with an “effective” permittivity and researches its influence on the microwave frequency and power. The dispersion relation of the SWS demonstrates that the introduction of the wall plasma will move the dispersion curves upward to some extent, which is confirmed by particle-in-cell (PIC) simulations and experiments. The plasma density and volume mainly affect the dispersion relation at the upper and lower frequency limits of each mode, respectively. Meanwhile, PIC simulations show that even though no direct power absorption exists since the wall plasma is assumed to be static, the introduction of the wall plasma may also lead to the decrease in microwave power by changing the electrodynamic property of the SWS.
Winey, J. M.; Gupta, Y. M.
2014-07-21
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
Kozhevnikov, V. A.; Sherman, S. G.
2008-11-15
The partial-wave inelasticity parameters of the amplitude for elastic pion-nucleon scattering are determined with the aid of the phenomenological amplitude for inelastic {pi}N {yields} {pi}{pi}N processes in the energy range extending to the threshold for the production of two pions. The resulting inelasticity parameters are compared with their counterparts derived from modern partial-wave analyses. The largest inelastic-scattering cross section in the P11 wave is in excellent agreement with the analogous value from the analysis performed at the George Washington University in 2006. For other waves, however, the present results differ in the majority of cases from respective values given by partial-wave analyses (the distinctions are especially large for the isospin-3/2 amplitudes).
Wang, J.; Zhang, X. Yu, L.; Zhao, X.
2014-12-15
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.
WE-E-9A-01: Ultrasound Elasticity
Emelianov, S; Hall, T; Bouchard, R
2014-06-15
Principles and techniques of ultrasound-based elasticity imaging will be presented, including quasistatic strain imaging, shear wave elasticity imaging, and their implementations in available systems. Deeper exploration of quasistatic methods, including elastic relaxation, and their applications, advantages, artifacts and limitations will be discussed. Transient elastography based on progressive and standing shear waves will be explained in more depth, along with applications, advantages, artifacts and limitations, as will measurement of complex elastic moduli. Comparisons will be made between ultrasound radiation force techniques, MR elastography, and the simple A mode plus mechanical plunger technique. Progress in efforts, such as that by the Quantitative Imaging Biomarkers Alliance, to reduce the differences in the elastic modulus reported by different commercial systems will be explained. Dr. Hall is on an Advisory Board for Siemens Ultrasound and has a research collaboration with them, including joint funding by R01CA140271 for nonlinear elasticity imaging. Learning Objectives: Be reminded of the long history of palpation of tissue elasticity for critical medical diagnosis and the relatively recent advances to be able to image tissue strain in response to an applied force. Understand the differences between shear wave speed elasticity measurement and imaging and understand the factors affecting measurement and image frame repletion rates. Understand shear wave propagation effects that can affect measurements, such as essentially lack of propagation in fluids and boundary effects, so important in thin layers. Know characteristics of available elasticity imaging phantoms, their uses and limitations. Understand thermal and cavitational limitations affecting radiation force-based shear wave imaging. Have learning and references adequate to for you to use in teaching elasticity imaging to residents and technologists. Be able to explain how elasticity measurement
Influence of defects on the charge density wave of ([SnSe]1+δ)1(VSe2)1 ferecrystals
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Falmbigl, Matthias; Putzky, Daniel; Ditto, Jeffrey; Esters, Marco; Bauers, Sage R.; Ronning, Filip; Johnson, David C.
2015-07-14
A series of ferecrystalline compounds ([SnSe]1+δ)1(VSe2)1 with varying Sn/V ratios were synthesized using the modulated elemental reactant technique. Temperature-dependent specific heat data reveal a phase transition at 102 K, where the heat capacity changes abruptly. An abrupt increase in electrical resistivity occurs at the same temperature, correlated with an abrupt increase in the Hall coefficient. Combined with the magnitude and nature of the specific heat discontinuity, this suggests that the transition is similar to the charge density wave transitions in transition metal dichalcogenides. An ordered intergrowth was formed over a surprisingly wide compositional range of Sn/V ratios of 0.89 ≤more » 1 + δ ≤ 1.37. X-ray diffraction and transmission electron microscopy reveal the formation of various volume defects in the compounds in response to the nonstoichiometry. The electrical resistivity and Hall coefficient data of samples with different Sn/V ratios show systematic variation in the carrier concentration with the Sn/V ratio. There is no significant change in the onset temperature of the charge density wave transition, only a variation in the carrier densities before and after the transition. Given the sensitivity of the charge density wave transitions of transition metal dichalcogenides to variations in composition, it is very surprising that the charge density wave transition observed at 102 K for ([SnSe]1.15)1(VSe2)1 is barely influenced by the nonstoichiometry and structural defects. As a result, this might be a consequence of the two-dimensional nature of the structurally independent VSe2 layers.« less
Correlations of πN partial waves for multireaction analyses
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Doring, M.; Revier, J.; Ronchen, D.; Workman, R. L.
2016-06-15
In the search for missing baryonic resonances, many analyses include data from a variety of pion- and photon-induced reactions. For elastic πN scattering, however, usually the partial waves of the SAID (Scattering Analysis Interactive Database) or other groups are fitted, instead of data. We provide the partial-wave covariance matrices needed to perform correlated χ2 fits, in which the obtained χ2 equals the actual χ2 up to nonlinear and normalization corrections. For any analysis relying on partial waves extracted from elastic pion scattering, this is a prerequisite to assess the significance of resonance signals and to assign any uncertainty on results.more » Lastly, the influence of systematic errors is also considered.« less
Influence of space charge wave on quasilinear theory of the free-electron laser saturation
Chakhmachi, A.; Maraghechi, B.
2009-07-15
A quasilinear theory is presented that describes the self-consistent evolution of the electron beam distribution function and fields in a free-electron laser when the space charge wave is present. In the Raman regime, a high-density electron beam has an appreciable space charge potential. A broad spectrum of waves is assumed in order to have a relatively wide range of resonant particles. A one-dimensional helical magnetic field is considered and the analysis is based on the Vlasov-Maxwell equations. Two coupled differential equations are derived, which, in conjunction with conservation laws, describe the quasilinear development by the diffusion of electrons in the momentum space. This leads to the saturation of the free-electron laser instability by the plateau formation. Analytical expressions for the growth rate and for the diffusion coefficient are derived, which reduced to those in the Compton regime under appropriate conditions. By use of the linear growth rate and diffusion coefficient, an analytical expression for efficiency in Raman regime was derived. A numerical analysis is conducted to study the effects of the spectral width of radiation and the thermal spread of the electron beam on the efficiency.
Seismic waves in rocks with fluids and fractures
Berryman, J.G.
2007-05-14
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.
Simultaneous structure and elastic wave velocity measurement...
Office of Scientific and Technical Information (OSTI)
Authors: Kono, Yoshio ; Park, Changyong ; Sakamaki, Tatsuya ; Kenny-Benson, Curtis ; Shen, Guoyin ; Wang, Yanbin 1 ; UC) 2 + Show Author Affiliations (CIW) ( Publication Date: ...
Mayrhofer, P. H.; Music, D.; Schneider, J. M.
2006-11-01
Ti{sub 1-x}Al{sub x}N films and/or their alloys are employed in many industrial applications due to their excellent mechanical and thermal properties. Synthesized by plasma-assisted vapor deposition, Ti{sub 1-x}Al{sub x}N is reported to crystallize in the cubic NaCl (c) structure for AlN mole fractions below 0.4-0.91, whereas at larger Al contents the hexagonal ZnS-wurtzite (w) structure is observed. Here we use ab initio calculations to analyze the effect of composition and Al distribution on the metal sublattice on phase stability, structure, and elastic properties of c-Ti{sub 1-x}Al{sub x}N and w-Ti{sub 1-x}Al{sub x}N. We show that the phase stability of supersaturated c-Ti{sub 1-x}Al{sub x}N not only depends on the chemical composition but also on the Al distribution of the metal sublattice. An increase of the metastable solubility limit of AlN in c-Ti{sub 1-x}Al{sub x}N from 0.64 to 0.74 is obtained by decreasing the number of Ti-Al bonds. This can be understood by considering the Al distribution induced changes of the electronic structure, bond energy, and configurational entropy. This may in part explain the large variation of the metastable solubility limit reported in the literature.
Plane wave method for elastic wave scattering by a heterogeneous...
Office of Scientific and Technical Information (OSTI)
This method is based upon the spatial Fourier transform of the seismic displacement-discontinuity (SDD) boundary conditions (also called linear slip interface conditions), and ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Winske, D.; Daughton, W.
2015-02-02
We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma, 19, 072109, 2012], but at higher electron beta (βe = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with Ti = Te. At higher electron beta the level of lower hybrid waves at saturation normalized to the ion thermal energy (βi = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, themore » waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3-D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.« less
Winske, D.; Daughton, W.
2015-02-02
We present results of three-dimensional electromagnetic particle-in-cell simulations of the lower hybrid ion ring instability, similar to our earlier results [D. Winske and W. Daughton, Phys. Plasma, 19, 072109, 2012], but at higher electron beta (βe = ratio of electron thermal pressure to magnetic pressure = 0.06, rather than at 0.006) with Ti = Te. At higher electron beta the level of lower hybrid waves at saturation normalized to the ion thermal energy (βi = 0.06 also) is only slightly smaller, but the corresponding magnetic fluctuations are about an order of magnitude larger, consistent with linear theory. After saturation, the waves evolve into whistler waves, through a number of possible mechanisms, with an average growth rate considerably smaller than the linear growth rate of the lower hybrid waves, to a peak fluctuation level that is about 20% above the lower hybrid wave saturation level. The ratio of the peak magnetic fluctuations associated with the whistler waves relative to those of the saturated lower hybrid waves, the ratio of the nonlinear growth rate of whistlers relative to the linear growth rate of lower hybrid waves, the amount of energy extracted from the ring and the amount of heating of the background ions and electrons are comparable to those in the lower electron beta 3-D simulation. This suggests that even at higher electron beta, the linear and nonlinear physics of the lower hybrid ion ring instability is dominated by electrostatic, wave-particle rather than wave-wave interactions.
Gray, George Thompson III; Hull, Lawrence Mark; Livescu, Veronica; Faulkner, James; Briggs, Matthew E.; Meyer, Ross Keith; Andrews, Heather Lynn; Hare, Steven John; Jakulewicz, Micah Shawn; Shinas, Michael A.
2015-03-30
Widespread research over the past five decades has provided a wealth of experimental data and insight concerning the shock hardening, damage evolution, and the spallation response of materials subjected to square-topped shock-wave loading profiles. However, fewer quantitative studies have been conducted on the effect of direct, in-contact, high explosive (HE)-driven Taylor wave (unsupported shocks) loading on the shock hardening, damage evolution, or spallation response of materials. Systematic studies quantifying the effect of sweeping-detonation wave loading are yet sparser. In this study, the damage evolution and spallation response of Ta is shown to be critically dependent on the peak shock stress, the geometry of the sample (flat or curved plate geometry), and the shock obliquity during sweeping-detonation-wave shock loading. Sweepingwave loading in the flat-plate geometry is observed to: a) yield a lower spall strength than previously documented for 1-D supported-shock-wave loading, b) exhibit increased shock hardening as a function of increasing obliquity, and c) lead to an increased incidence of deformation twin formation with increasing shock obliquity. Sweeping-wave loading of a 10 cm radius curved Ta plate is observed to: a) lead to an increase in the shear stress as a function of increasing obliquity, b) display a more developed level of damage evolution, extensive voids and coalescence, and lower spall strength with obliquity in the curved plate than seen in the flat-plate sweeping-detonation wave loading for an equivalent HE loading, and c) no increased propensity for deformation twin formation with increasing obliquity as seen in the flat-plate geometry. The overall observations comparing and contrasting the flat versus curved sweeping-wave spall experiments with 1D loaded spallation behavior suggests a coupled influence of obliquity and geometry on dynamic shock-induced damage evolution and spall strength. Coupled experimental and modeling research
Hydrodynamic Elastic Magneto Plastic
Energy Science and Technology Software Center (OSTI)
1985-02-01
The HEMP code solves the conservation equations of two-dimensional elastic-plastic flow, in plane x-y coordinates or in cylindrical symmetry around the x-axis. Provisions for calculation of fixed boundaries, free surfaces, pistons, and boundary slide planes have been included, along with other special conditions.
Wang, Jian-Yong; Cheng, Xue-Ping; Tang, Xiao-Yan; Yang, Jian-Rong; Ren, Bo
2014-03-15
The oblique propagation of ion-acoustic soliton-cnoidal waves in a magnetized electron-positron-ion plasma with superthermal electrons is studied. Linear dispersion relations of the fast and slow ion-acoustic modes are discussed under the weak and strong magnetic field situations. By means of the reductive perturbation approach, Korteweg-de Vries equations governing ion-acoustic waves of fast and slow modes are derived, respectively. Explicit interacting soliton-cnoidal wave solutions are obtained by the generalized truncated Painlevé expansion. It is found that every peak of a cnoidal wave elastically interacts with a usual soliton except for some phase shifts. The influence of the electron superthermality, positron concentration, and magnetic field obliqueness on the soliton-cnoidal wave are investigated in detail.
Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.
1988-12-01
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.
Design guidance for elastic followup
Naugle, F.V.
1983-01-01
The basic mechanism of elastic followup is discussed in relation to piping design. It is shown how mechanistic insight gained from solutions for a two-bar problem can be used to identify dominant design parameters and to determine appropriate modifications where elastic followup is a potential problem. It is generally recognized that quantitative criteria are needed for elastic followup in the creep range where badly unbalanced lines can pose potential problems. Approaches for criteria development are discussed.
Solitary waves in nonlinear Dirac equation. From field theory to Dirac materials
Saxena, Avadh
2015-11-02
This report describes the implementation of nonlinear Dirac equations in the calculation of solitary waves. Conclusions and comments on quantum elasticity are also included.
Estimating Price Elasticity using Market-Level Appliance Data
Fujita, K. Sydny
2015-08-04
This report provides and update to and expansion upon our 2008 LBNL report “An Analysis of the Price Elasticity of Demand for Appliances,” in which we estimated an average relative price elasticity of -0.34 for major household appliances (Dale and Fujita 2008). Consumer responsiveness to price change is a key component of energy efficiency policy analysis; these policies influence consumer purchases through price both explicitly and implicitly. However, few studies address appliance demand elasticity in the U.S. market and public data sources are generally insufficient for rigorous estimation. Therefore, analysts have relied on a small set of outdated papers focused on limited appliance types, assuming long-term elasticities estimated for other durables (e.g., vehicles) decades ago are applicable to current and future appliance purchasing behavior. We aim to partially rectify this problem in the context of appliance efficiency standards by revisiting our previous analysis, utilizing data released over the last ten years and identifying additional estimates of durable goods price elasticities in the literature. Reviewing the literature, we find the following ranges of market-level price elasticities: -0.14 to -0.42 for appliances; -0.30 to -1.28 for automobiles; -0.47 to -2.55 for other durable goods. Brand price elasticities are substantially higher for these product groups, with most estimates -2.0 or more elastic. Using market-level shipments, sales value, and efficiency level data for 1989-2009, we run various iterations of a log-log regression model, arriving at a recommended range of short run appliance price elasticity between -0.4 and -0.5, with a default value of -0.45.
The Effect of Crack Orientation on the Nonlinear Interaction of a P-wave with an S-wave
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
TenCate, J. A.; Malcolm, A. E.; Feng, X.; Fehler, M. C.
2016-06-06
Cracks, joints, fluids, and other pore-scale structures have long been hypothesized to be the cause of the large elastic nonlinearity observed in rocks. It is difficult to definitively say which pore-scale features are most important, however, because of the difficulty in isolating the source of the nonlinear interaction. In this work, we focus on the influence of cracks on the recorded nonlinear signal and in particular on how the orientation of microcracks changes the strength of the nonlinear interaction. We do this by studying the effect of orientation on the measurements in a rock with anisotropy correlated with the presencemore » and alignment of microcracks. We measure the nonlinear response via the traveltime delay induced in a low-amplitude P wave probe by a high-amplitude S wave pump. We find evidence that crack orientation has a significant effect on the nonlinear signal.« less
Bradley, D.; Kalghatgi, G.T.
2009-12-15
The functional relationship of autoignition delay time with temperature and pressure is employed to derive the propagation velocities of autoignitive reaction fronts for particular reactivity gradients, once autoignition has been initiated. In the present study of a variety of premixtures, with different functional relationships, such gradients comprise fixed initial temperature gradients. The smaller is the ratio of the acoustic speed through the mixture to the localised velocity of the autoignitive front, the greater are the amplitude and frequency of the induced pressure wave. This might lead to damaging engine knock. At higher values of the ratio, the autoignition can be benign with only small over-pressures. This approach to the effects of autoignition is confirmed by its application to a variety of experimental studies involving: (i)Imposed temperature gradients in a rapid compression and expansion machine. (ii)Onset of knock in an engine with advancing spark timing. (iii)Development of autoignition at a single hot spot in an engine. (iv)Autoignition fronts initiated by several hot spots. There is much diversity in the effects that can be produced by different fuels in different ranges of temperature and pressure. Higher values of autoignitive propagation speeds lead to increasingly severe engine knock. Such effects cannot always be predicted from the Research and Motor octane numbers. (author)
Elastic-Wavefield Seismic Stratigraphy: A New Seismic Imaging Technology
Bob A. Hardage; Milo M. Backus; Michael V. DeAngelo; Sergey Fomel; Khaled Fouad; Robert J. Graebner; Paul E. Murray; Randy Remington; Diana Sava
2006-07-31
The purpose of our research has been to develop and demonstrate a seismic technology that will provide the oil and gas industry a better methodology for understanding reservoir and seal architectures and for improving interpretations of hydrocarbon systems. Our research goal was to expand the valuable science of seismic stratigraphy beyond the constraints of compressional (P-P) seismic data by using all modes (P-P, P-SV, SH-SH, SV-SV, SV-P) of a seismic elastic wavefield to define depositional sequences and facies. Our objective was to demonstrate that one or more modes of an elastic wavefield may image stratal surfaces across some stratigraphic intervals that are not seen by companion wave modes and thus provide different, but equally valid, information regarding depositional sequences and sedimentary facies within that interval. We use the term elastic wavefield stratigraphy to describe the methodology we use to integrate seismic sequences and seismic facies from all modes of an elastic wavefield into a seismic interpretation. We interpreted both onshore and marine multicomponent seismic surveys to select the data examples that we use to document the principles of elastic wavefield stratigraphy. We have also used examples from published papers that illustrate some concepts better than did the multicomponent seismic data that were available for our analysis. In each interpretation study, we used rock physics modeling to explain how and why certain geological conditions caused differences in P and S reflectivities that resulted in P-wave seismic sequences and facies being different from depth-equivalent S-wave sequences and facies across the targets we studied.
Elastic-Wavefield Seismic Stratigraphy: A New Seismic Imaging Technology
Bob A. Hardage
2005-07-31
We have developed a numerical technique that will adjust 3-D S-wave seismic images so that they are depth equivalent to 3-D P-wave seismic images. The ability to make this type of P-SV to P-P depth registration is critical to our elastic wavefield seismic stratigraphy research because we now have higher confidence that depth-equivalent data windows are being used in the P-SV to P-P comparisons that we are making.
Lunt, A. J. G. Xie, M. Y.; Baimpas, N.; Korsunsky, A. M.; Zhang, S. Y.; Kabra, S.; Kelleher, J.; Neo, T. K.
2014-08-07
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.
Elasticity of crystalline molecular explosives
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hooks, Daniel E.; Ramos, Kyle J.; Bolme, C. A.; Cawkwell, Marc J.
2015-04-14
Crystalline molecular explosives are key components of engineered explosive formulations. In precision applications a high degree of consistency and predictability is desired under a range of conditions to a variety of stimuli. Prediction of behaviors from mechanical response and failure to detonation initiation and detonation performance of the material is linked to accurate knowledge of the material structure and first stage of deformation: elasticity. The elastic response of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and cyclotetramethylene tetranitramine (HMX), including aspects of material and measurement variability, and computational methods are described in detail. Experimental determinations of elastic tensors are compared, andmore » an evaluation of sources of error is presented. Furthermore, computed elastic constants are also compared for these materials and for triaminotrinitrobenzene (TATB), for which there are no measurements.« less
Elasticity of crystalline molecular explosives
Hooks, Daniel E.; Ramos, Kyle J.; Bolme, C. A.; Cawkwell, Marc J.
2015-04-14
Crystalline molecular explosives are key components of engineered explosive formulations. In precision applications a high degree of consistency and predictability is desired under a range of conditions to a variety of stimuli. Prediction of behaviors from mechanical response and failure to detonation initiation and detonation performance of the material is linked to accurate knowledge of the material structure and first stage of deformation: elasticity. The elastic response of pentaerythritol tetranitrate (PETN), cyclotrimethylene trinitramine (RDX), and cyclotetramethylene tetranitramine (HMX), including aspects of material and measurement variability, and computational methods are described in detail. Experimental determinations of elastic tensors are compared, and an evaluation of sources of error is presented. Furthermore, computed elastic constants are also compared for these materials and for triaminotrinitrobenzene (TATB), for which there are no measurements.
Elastic scattering and total cross sections
Cahn, R.N.
1990-03-01
This report discusses concepts of elastic scattering and cross sections of proton-proton interactions. (LSP)
Mazur, V. A. Chuiko, D. A.
2013-12-15
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 Alfvn 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.
Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin
2015-06-05
The development of reliable methods for upscaling fine scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters for materials such as finely layered media or randomly oriented or aligned fractures. In such cases, the analytic solutions for upscaled properties can be used for accurate prediction of wave propagation. However, such theories cannot be applied directly to homogenize elastic media with more complex, arbitrary spatial heterogeneity. We therefore propose a numerical homogenization algorithm based on multiscale finite element methods for simulating elastic wave propagation in heterogeneous, anisotropic elastic media. Specifically, our method used multiscale basis functions obtained from a local linear elasticity problem with appropriately defined boundary conditions. Homogenized, effective medium parameters were then computed using these basis functions, and the approach applied a numerical discretization that is similar to the rotated staggered-grid finite difference scheme. Comparisons of the results from our method and from conventional, analytical approaches for finely layered media showed that the homogenization reliably estimated elastic parameters for this simple geometry. Additional tests examined anisotropic models with arbitrary spatial heterogeneity where the average size of the heterogeneities ranged from several centimeters to several meters, and the ratio between the dominant wavelength and the average size of the arbitrary heterogeneities ranged from 10 to 100. Comparisons to finite-difference simulations proved that the numerical homogenization was equally accurate for these complex cases.
Visualization of elastic wavefields computed with a finite difference code
Larsen, S.; Harris, D.
1994-11-15
The authors have developed a finite difference elastic propagation model to simulate seismic wave propagation through geophysically complex regions. To facilitate debugging and to assist seismologists in interpreting the seismograms generated by the code, they have developed an X Windows interface that permits viewing of successive temporal snapshots of the (2D) wavefield as they are calculated. The authors present a brief video displaying the generation of seismic waves by an explosive source on a continent, which propagate to the edge of the continent then convert to two types of acoustic waves. This sample calculation was part of an effort to study the potential of offshore hydroacoustic systems to monitor seismic events occurring onshore.
Rykounov, A. A.
2015-06-07
The influence of pressure on the thermodynamic, structural, and elastic properties of the 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) molecular crystal at T = 0 is systematically studied. Calculations are carried out using density functional theory methods in a plane wave basis set with dispersion corrections for the exchange-correlation part of total energy, and ultrasoft pseudopotentials. The equilibrium unit cell parameters, the cold compression curve in the pressure range of 0–50 GPa and the sound speeds are computed. The effect of finite pressure on the molecular structure of TATB is elucidated from the analysis of relative changes in the intra- and intermolecular geometrical parameters. For the first time, the full set of elastic constants of this crystal at zero and non-zero pressures is determined from ab initio calculations. The resulted structural, elastic, and acoustic properties of TATB are shown to be in a good agreement with available experimental and theoretical data.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gao, Kai; Chung, Eric T.; Gibson, Richard L.; Fu, Shubin; Efendiev, Yalchin
2015-06-05
The development of reliable methods for upscaling fine scale models of elastic media has long been an important topic for rock physics and applied seismology. Several effective medium theories have been developed to provide elastic parameters for materials such as finely layered media or randomly oriented or aligned fractures. In such cases, the analytic solutions for upscaled properties can be used for accurate prediction of wave propagation. However, such theories cannot be applied directly to homogenize elastic media with more complex, arbitrary spatial heterogeneity. We therefore propose a numerical homogenization algorithm based on multiscale finite element methods for simulating elasticmore » wave propagation in heterogeneous, anisotropic elastic media. Specifically, our method used multiscale basis functions obtained from a local linear elasticity problem with appropriately defined boundary conditions. Homogenized, effective medium parameters were then computed using these basis functions, and the approach applied a numerical discretization that is similar to the rotated staggered-grid finite difference scheme. Comparisons of the results from our method and from conventional, analytical approaches for finely layered media showed that the homogenization reliably estimated elastic parameters for this simple geometry. Additional tests examined anisotropic models with arbitrary spatial heterogeneity where the average size of the heterogeneities ranged from several centimeters to several meters, and the ratio between the dominant wavelength and the average size of the arbitrary heterogeneities ranged from 10 to 100. Comparisons to finite-difference simulations proved that the numerical homogenization was equally accurate for these complex cases.« less
Jamison, Ryan Dale; Shen, Yu-Lin
2015-08-13
Nanoindentation is useful for evaluating the mechanical properties, such as elastic modulus, of multilayer thin film materials. A fundamental assumption in the derivation of the elastic modulus from nanoindentation is that the unloading process is purely elastic. In this work, the validity of elastic assumption as it applies to multilayer thin films is studied using the finite element method. The elastic modulus and hardness from the model system are compared to experimental results to show validity of the model. Plastic strain is shown to increase in the multilayer system during the unloading process. Additionally, the indentation-derived modulus of a monolayer material shows no dependence on unloading plasticity while the modulus of the multilayer system is dependent on unloading-induced plasticity. Lastly, the cyclic behavior of the multilayer thin film is studied in relation to the influence of unloading-induced plasticity. Furthermore, it is found that several cycles are required to minimize unloading-induced plasticity.
Indentation-derived elastic modulus of multilayer thin films: Effect of unloading induced plasticity
Jamison, Ryan Dale; Shen, Yu -Lin
2015-08-13
Nanoindentation is useful for evaluating the mechanical properties, such as elastic modulus, of multilayer thin film materials. A fundamental assumption in the derivation of the elastic modulus from nanoindentation is that the unloading process is purely elastic. In this work, the validity of elastic assumption as it applies to multilayer thin films is studied using the finite element method. The elastic modulus and hardness from the model system are compared to experimental results to show validity of the model. Plastic strain is shown to increase in the multilayer system during the unloading process. Additionally, the indentation-derived modulus of a monolayer material shows no dependence on unloading plasticity while the modulus of the multilayer system is dependent on unloading-induced plasticity. Lastly, the cyclic behavior of the multilayer thin film is studied in relation to the influence of unloading-induced plasticity. Furthermore, it is found that several cycles are required to minimize unloading-induced plasticity.
Elastic Hadron Scattering on Li Isotopes at Intermediate Energies
Zhusupov, M.A.; Imambekov, O.; Ibraeva, E.T.
2005-01-01
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.
Erba, A. Mahmoud, A.; Dovesi, R.; Belmonte, D.
2014-03-28
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.
First Principles Calculations for X-ray Resonant Spectra and Elastic Properties
Yongbin Lee
2006-05-01
In this thesis, we discuss applications of first principles methods to x-ray resonant spectra and elastic properties calculation. We start with brief reviews about theoretical background of first principles methods, such as density functional theory, local density approximation (LDA), LDA+U, and the linear augmented plane wave (LAPW) method to solve Kohn-Sham equations. After that we discuss x-ray resonant scattering (XRMS), x-ray magnetic circular dichroism (XMCD) and the branching problem in the heavy rare earths Ledges. In the last chapter we discuss the elastic properties of the second hardest material AlMgB{sub 14}.
Electron elastic differential cross sections for free atoms using a scientific visualization package
Flox, L.; Ughrin, J.; Ozturk, N.
1992-12-01
Differential cross sections (DCS) of electron elastic scattering by free indium and antimony atoms are presented. The DCS were calculated using the method of partial waves and the optical model. The optical potential consists of static, polarization and exchange terms. Comparisons of experimental data for argon and mercury are used to establish the credibility of the model. The elastic data for indium and antimony covers the range from a few hundred eV`s to a few KeV. The data are presented in a Spyglass{reg_sign} scientific visualization package format.
Influence of defects on the charge density wave of ([SnSe]_{1+?})_{1}(VSe_{2})_{1} ferecrystals
Falmbigl, Matthias; Putzky, Daniel; Ditto, Jeffrey; Esters, Marco; Bauers, Sage R.; Ronning, Filip; Johnson, David C.
2015-07-14
A series of ferecrystalline compounds ([SnSe]_{1+?})_{1}(VSe_{2})_{1} with varying Sn/V ratios were synthesized using the modulated elemental reactant technique. Temperature-dependent specific heat data reveal a phase transition at 102 K, where the heat capacity changes abruptly. An abrupt increase in electrical resistivity occurs at the same temperature, correlated with an abrupt increase in the Hall coefficient. Combined with the magnitude and nature of the specific heat discontinuity, this suggests that the transition is similar to the charge density wave transitions in transition metal dichalcogenides. An ordered intergrowth was formed over a surprisingly wide compositional range of Sn/V ratios of 0.89 ? 1 + ? ? 1.37. X-ray diffraction and transmission electron microscopy reveal the formation of various volume defects in the compounds in response to the nonstoichiometry. The electrical resistivity and Hall coefficient data of samples with different Sn/V ratios show systematic variation in the carrier concentration with the Sn/V ratio. There is no significant change in the onset temperature of the charge density wave transition, only a variation in the carrier densities before and after the transition. Given the sensitivity of the charge density wave transitions of transition metal dichalcogenides to variations in composition, it is very surprising that the charge density wave transition observed at 102 K for ([SnSe]_{1.15})_{1}(VSe_{2})_{1} is barely influenced by the nonstoichiometry and structural defects. As a result, this might be a consequence of the two-dimensional nature of the structurally independent VSe_{2} layers.
High elastic modulus polymer electrolytes
Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel
2013-10-22
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.
Influence of Elastic and Surface Strains on the Optical Properties...
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of Semiconducting Core-Shell Nanoparticles Citation Details In-Document Search ... of Semiconducting Core-Shell Nanoparticles Authors: Mangeri, John ; Heinonen, ...
Advanced Elastic/Inelastic Nuclear Data Development Project ...
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Advanced ElasticInelastic Nuclear Data Development Project Citation Details In-Document Search Title: Advanced ElasticInelastic Nuclear Data Development Project The optical model ...
Polycrystalline gamma plutonium's elastic moduli versus temperature
Migliori, Albert; Betts, J; Trugman, A; Mielke, C H; Mitchell, J N; Ramos, M; Stroe, I
2009-01-01
Resonant ultrasound spectroscopy was used to measure the elastic properties of pure polycrystalline {sup 239}Pu in the {gamma} phase. Shear and longitudinal elastic moduli were measured simultaneously and the bulk modulus was computed from them. A smooth, linear, and large decrease of all elastic moduli with increasing temperature was observed. They calculated the Poisson ratio and found that it increases from 0.242 at 519 K to 0.252 at 571 K. These measurements on extremely well characterized pure Pu are in agreement with other reported results where overlap occurs.
Cascading elastic perturbation in Japan due to the 2012 Mw 8.6 Indian Ocean Earthquake
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Delorey, A. A.; Johnson, P. A.; Chao, K.; Obara, K.
2015-10-02
Since the discovery of extensive earthquake triggering occurring in response to the 1992 Mw 7.3 Landers earthquake, it is now well established that seismic waves from earthquakes can trigger other earthquakes, tremor, slow slip, and pore pressure changes. Our contention is that earthquake triggering is one manifestation of a more widespread elastic disturbance that reveals information about Earth’s stress state. Earth’s stress state is central to our understanding of both natural and anthropogenic-induced crustal processes. Here we present that seismic waves from distant earthquakes may perturb stresses and frictional properties on faults and elastic moduli of the crust in cascadingmore » fashion. Transient dynamic stresses place crustal material into a metastable state during which material recovers through a process termed slow dynamics. This observation of widespread, dynamically induced elastic perturbation, including systematic migration of offshore seismicity, strain transients, and velocity transients, presents a new characterization of Earth’s elastic system that will advance our understanding of plate tectonics, seismicity, and seismic hazards.« less
Mahmoud, A.; Erba, A. Dovesi, R.; Doll, K.
2014-06-21
A general methodology has been devised and implemented into the solid-state ab initio quantum-mechanical CRYSTAL program for studying the evolution under geophysical pressure of the elastic anisotropy of crystalline materials. This scheme, which fully exploits both translational and point symmetry of the crystal, is developed within the formal frame of one-electron Hamiltonians and atom-centered basis functions. Six silicate garnet end-members, among the most important rock-forming minerals of the Earth's mantle, are considered, whose elastic anisotropy is fully characterized under high hydrostatic compressions, up to 60 GPa. The pressure dependence of azimuthal anisotropy and shear-wave birefringence of seismic wave velocities for these minerals are accurately simulated and compared with available single-crystal measurements.
Structure of light neutron-rich nuclei and mechanism of elastic proton scattering
Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.
2011-11-15
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.
Revisit of the relationship between the elastic properties and sound velocities at high pressures
Wang, Chenju; Yan, Xiaozhen; Xiang, Shikai Chen, Haiyan; Gu, Jianbing; Yu, Yin; Kuang, Xiaoyu
2014-09-14
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.
Elastic actuator for precise force control
Pratt, G.A.; Williamson, M.M.
1997-07-22
The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section. 30 figs.
Elastic actuator for precise force control
Pratt, Gill A.; Williamson, Matthew M.
1997-07-22
The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion. The invention also provides a torsional spring consisting of a flexible structure having at least three flat sections each connected integrally with and extending radially from a central section. Each flat section extends axially along the central section from a distal end of the central section to a proximal end of the central section.
Artemyev, A. V.; Mourenas, D.; Krasnoselskikh, V. V.
2015-06-15
In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.
Seismic Waves in Rocks with Fluids and Fractures
Berryman, J G
2006-02-06
Seismic wave propagation through the earth is often strongly affected by the presence of fractures. When these fractures are filled with fluids (oil, gas, water, CO{sub 2}, etc.), the type and state of the fluid (liquid or gas) can make a large difference in the response of the seismic waves. This paper will summarize some early work of the author on methods of deconstructing the effects of fractures, and any fluids within these fractures, on seismic wave propagation as observed in reflection seismic data. Methods to be explored here include Thomsen's anisotropy parameters for wave moveout (since fractures often induce elastic anisotropy), and some very convenient fracture parameters introduced by Sayers and Kachanov that permit a relatively simple deconstruction of the elastic behavior in terms of fracture parameters (whenever this is appropriate).
Elasticity and Inverse Temperature Transition in Elastin
Perticaroli, Stefania; Ehlers, Georg; Jalarvo, Niina; Katsaras, John; Nickels, Jonathan D.
2015-09-22
Structurally, elastin is protein and biomaterial that provides elasticity and resilience to a range of tissues. This work provides insights into the elastic properties of elastin and its peculiar inverse temperature transition (ITT). These features are dependent on hydration of elastin and are driven by a similar mechanism of hydrophobic collapse to an entropically favorable state. Moreover, when using neutron scattering, we quantify the changes in the geometry of molecular motions above and below the transition temperature, showing a reduction in the displacement of water-induced motions upon hydrophobic collapse at the ITT. Finally, we measured the collective vibrations of elastin gels as a function of elongation, revealing no changes in the spectral features associated with local rigidity and secondary structure, in agreement with the entropic origin of elasticity.
Elasticity and Inverse Temperature Transition in Elastin
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Perticaroli, Stefania; Ehlers, Georg; Jalarvo, Niina; Katsaras, John; Nickels, Jonathan D.
2015-09-22
Structurally, elastin is protein and biomaterial that provides elasticity and resilience to a range of tissues. This work provides insights into the elastic properties of elastin and its peculiar inverse temperature transition (ITT). These features are dependent on hydration of elastin and are driven by a similar mechanism of hydrophobic collapse to an entropically favorable state. Moreover, when using neutron scattering, we quantify the changes in the geometry of molecular motions above and below the transition temperature, showing a reduction in the displacement of water-induced motions upon hydrophobic collapse at the ITT. Finally, we measured the collective vibrations of elastinmore » gels as a function of elongation, revealing no changes in the spectral features associated with local rigidity and secondary structure, in agreement with the entropic origin of elasticity.« less
Ding, Ke; Yang, Zhong; Xu, Jian-zhong; Liu, Wen-ying; Zeng, Qiang; Hou, Fang; Lin, Sen
2015-09-10
The application of satellite cell-derived myoblasts in regenerative medicine has been restricted by the rapid loss of stemness during in vitro cell expansion using traditional culture systems. However, studies published in the past decade have highlighted the influence of substrate elasticity on stem cell fate and revealed that culture on a soft hydrogel substrate can promote self-renewal and prolong the regenerative potential of muscle stem cells. Whether hydrogel substrates have similar effects after long-term robust expansion remains to be determined. Herein we prepared an elastic chitosan/beta-glycerophosphate/collagen hydrogel mimicking the soft microenvironment of muscle tissues for use as the substrate for satellite cell culture and investigated its influence on long-term cell expansion. After 20 passages in culture, satellite cell-derived myoblasts cultured on our hydrogel substrate exhibited significant improvements in proliferation capability, cell viability, colony forming frequency, and potential for myogenic differentiation compared to those cultured on a routine rigid culture surface. Immunochemical staining and western blot analysis both confirmed that myoblasts cultured on the hydrogel substrate expressed higher levels of several differentiation-related markers, including Pax7, Pax3, and SSEA-1, and a lower level of MyoD compared to myoblasts cultured on rigid culture plates (all p<0.05). After transplantation into the tibialis anterior of nude mice, myoblasts that had been cultured on the hydrogel substrate demonstrated a significantly greater engraftment efficacy than those cultured on the traditional surface. Collectively, these results indicate that the elastic hydrogel substrate supported robust expansion of murine myoblasts and enhanced their engraftment in vivo. - Highlights: • An elastic hydrogel was designed to mimic the pliable muscle tissue microenvironment. • Myoblasts retained their stemness in long-term culture on the elastic
Indentation-derived elastic modulus of multilayer thin films: Effect of unloading induced plasticity
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jamison, Ryan Dale; Shen, Yu -Lin
2015-08-13
Nanoindentation is useful for evaluating the mechanical properties, such as elastic modulus, of multilayer thin film materials. A fundamental assumption in the derivation of the elastic modulus from nanoindentation is that the unloading process is purely elastic. In this work, the validity of elastic assumption as it applies to multilayer thin films is studied using the finite element method. The elastic modulus and hardness from the model system are compared to experimental results to show validity of the model. Plastic strain is shown to increase in the multilayer system during the unloading process. Additionally, the indentation-derived modulus of a monolayermore » material shows no dependence on unloading plasticity while the modulus of the multilayer system is dependent on unloading-induced plasticity. Lastly, the cyclic behavior of the multilayer thin film is studied in relation to the influence of unloading-induced plasticity. Furthermore, it is found that several cycles are required to minimize unloading-induced plasticity.« less
Neutrino-Nucleon Neutrino-Nucleon Neutral Current Elastic Neutral Current Elastic
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Neutrino-Nucleon Neutral Current Elastic Neutral Current Elastic Interactions in MiniBooNE Interactions in MiniBooNE Denis Perevalov Denis Perevalov University of Alabama University of Alabama for the MiniBooNE collaboration for the MiniBooNE collaboration presented by: Rex Tayloe, Indiana University Nuint '09 2 Neutrino-Nucleon NC Elastic Scattering p , n p , n Z p,n p,n - The most fundamental NC probe of the nucleus/nucleon. - Unlike CC
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Microfabricated bulk wave acoustic bandgap device
Olsson, Roy H.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, legal representative, Carol
2010-11-23
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.; El-Kady, Ihab F.; McCormick, Frederick; Fleming, James G.; Fleming, Carol
2010-06-08
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).
Mechanism of elastic and inelastic proton scattering on a {sup 15}C nucleus in diffraction theory
Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.
2012-11-15
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.
ELEMENTARY APPROACH TO SELF-ASSEMBLY AND ELASTIC PROPERTIES OF RANDOM COPOLYMERS
S. M. CHITANVIS
2000-10-01
The authors have mapped the physics of a system of random copolymers onto a time-dependent density functional-type field theory using techniques of functional integration. Time in the theory is merely a label for the location of a given monomer along the extent of a flexible chain. We derive heuristically within this approach a non-local constraint which prevents segments on chains in the system from straying too far from each other, and leads to self-assembly. The structure factor is then computed in a straightforward fashion. The long wave-length limit of the structure factor is used to obtain the elastic modulus of the network. It is shown that there is a surprising competition between the degree of micro-phase separation and the elastic moduli of the system.
Locality and rapidity of the ultra-large elastic deformation...
Office of Scientific and Technical Information (OSTI)
Locality and rapidity of the ultra-large elastic deformation of Nb nanowires in a NiTi phase-transforming matrix Title: Locality and rapidity of the ultra-large elastic deformation ...
Effect of thermo-mechanical treatment on mechanical and elastic...
Office of Scientific and Technical Information (OSTI)
Effect of thermo-mechanical treatment on mechanical and elastic properties of Ti-36Nb-5Zr alloy Title: Effect of thermo-mechanical treatment on mechanical and elastic properties of ...
U?ur, ?ule; ?yigr, Ahmet
2014-10-06
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 222 supercell.
Cascading elastic perturbation in Japan due to the 2012 M_{w} 8.6 Indian Ocean Earthquake
Delorey, A. A.; Johnson, P. A.; Chao, K.; Obara, K.
2015-10-02
Since the discovery of extensive earthquake triggering occurring in response to the 1992 M_{w} 7.3 Landers earthquake, it is now well established that seismic waves from earthquakes can trigger other earthquakes, tremor, slow slip, and pore pressure changes. Our contention is that earthquake triggering is one manifestation of a more widespread elastic disturbance that reveals information about Earths stress state. Earths stress state is central to our understanding of both natural and anthropogenic-induced crustal processes. Here we present that seismic waves from distant earthquakes may perturb stresses and frictional properties on faults and elastic moduli of the crust in cascading fashion. Transient dynamic stresses place crustal material into a metastable state during which material recovers through a process termed slow dynamics. This observation of widespread, dynamically induced elastic perturbation, including systematic migration of offshore seismicity, strain transients, and velocity transients, presents a new characterization of Earths elastic system that will advance our understanding of plate tectonics, seismicity, and seismic hazards.
Three-dimensional elastic lidar winds
Buttler, W.T.
1996-07-01
Maximum cross-correlation techniques have been used with satellite data to estimate winds and sea surface velocities for several years. Los Alamos National Laboratory (LANL) is currently using a variation of the basic maximum cross-correlation technique, coupled with a deterministic application of a vector median filter, to measure transverse winds as a function of range and altitude from incoherent elastic backscatter lidar data taken throughout large volumes within the atmospheric boundary layer. Hourly representations of three- dimensional wind fields, derived from elastic lidar data taken during an air-quality study performed in a region of complex terrain near Sunland Park, New Mexico, are presented and compared with results from an Environmental Protection Agency (EPA) approved laser doppler velocimeter. The wind fields showed persistent large scale eddies as well as general terrain following winds in the Rio Grande valley.
Effect of Nuclear Elastic Scattering on Neutral Beam Injection Heating in Thermonuclear Plasmas
Matsuura, H.; Nakao, Y.
2005-04-15
An effect of the nuclear elastic scattering (NES) on the neutral beam injection (NBI) plasma heating was examined by solving the Boltzmann-Fokker-Planck (BFP) equation for beam ion in the deuterium-tritium (DT) thermonuclear plasmas. The BFP calculations show that the enhancement in the fraction of the NBI heating power deposited to ions due to NES becomes appreciable when beam energy is larger than 1MeV, and the enhancement is strongly influenced by plasma parameters.
EXPLORING FOR SUBTLE MISSION CANYON STRATIGRAPHIC TRAPS WITH ELASTIC WAVEFIELD SEISMIC TECHNOLOGY
John Beecherl
2004-02-01
The 9C3D seismic data that will form the principal data base needed for this research program have been successfully acquired. The seismic field data exhibit a good signal-to-noise (S/N) ratio for all elastic-wave modes. Thus the major hurdle of acquiring optimal-quality 9-C seismic data has been cleared. The stratigraphic oil-reservoir target that will be the imaging objective of the seismic data-processing effort is described in this report to indicate the challenge that now confronts the data-processing phase of the project.
Temperature-dependent elastic properties of Ti{sub 1−x}Al{sub x}N alloys
Shulumba, Nina; Hellman, Olle; Rogström, Lina; Raza, Zamaan; Tasnádi, Ferenc; Odén, Magnus; Abrikosov, Igor A.
2015-12-07
Ti{sub 1−x}Al{sub x}N is a technologically important alloy that undergoes a process of high temperature age-hardening that is strongly influenced by its elastic properties. We have performed first principles calculations of the elastic constants and anisotropy using the symmetry imposed force constant temperature dependent effective potential method, which include lattice vibrations and therefore the effects of temperature, including thermal expansion and intrinsic anharmonicity. These are compared with in situ high temperature x-ray diffraction measurements of the lattice parameter. We show that anharmonic effects are crucial to the recovery of finite temperature elasticity. The effects of thermal expansion and intrinsic anharmonicity on the elastic constants are of the same order, and cannot be considered separately. Furthermore, the effect of thermal expansion on elastic constants is such that the volume change induced by zero point motion has a significant effect. For TiAlN, the elastic constants soften non-uniformly with temperature: C{sub 11} decreases substantially when the temperature increases for all compositions, resulting in an increased anisotropy. These findings suggest that an increased Al content and annealing at higher temperatures will result in a harder alloy.
Turbulence elasticityA new mechanism for transport barrier dynamics
Guo, Z. B.; Diamond, P. H.; Kosuga, Y.; Grcan, . D.
2014-09-15
We present a new, unified model of transport barrier formation in elastic drift wave-zonal flow (DW-ZF) turbulence. A new physical quantitythe delay time (i.e., the mixing time for the DW turbulence)is demonstrated to parameterize each stage of the transport barrier formation. Quantitative predictions for the onset of limit-cycle-oscillation (LCO) among DW and ZF intensities (also denoted as I-mode) and I-mode to high-confinement mode (H-mode) transition are also given. The LCO occurs when the ZF shearing rate (|?v?{sub ZF}{sup ?}|) enters the regime ??{sub k}<|?V?{sub ZF}{sup ?}|?{sub cr}{sup ?1}, where the mean E??B shear flow driven by ion pressure locks the DW-ZF system to the H-mode by reducing the delay time below the threshold value.
Elastic scattering of /sup 16/O by /sup 28/Si
Shkolnik, V.; Dehnhard, D.; Franey, M.A.
1983-08-01
Differential cross sections were measured in small angular steps at forward angles for the elastic scattering of /sup 16/O from /sup 28/Si, /sup 29/Si, and /sup 30/Si at E/sub lab/ = 60 MeV and from /sup 28/Si at six other incident energies between 45 and 63 MeV. The angular position of a peak in the diffraction pattern at theta/sub c.m./approx. =75/sup 0/ was measured as a function of the incident energy between 55 and 63 MeV in 0.5 MeV steps. Close fits to these angular distributions and those of other authors at energies between 41 and 81 MeV, some spanning the whole angular range up to 180/sup 0/, and the excitation functions at 90/sup 0/ and 180/sup 0/, were obtained in an optical model analysis. A consistent description of the data was found by the use of a surface-transparent and parity-dependent potential with a real part able to generate a pocket in the total potential. The real and imaginary strengths depend quite strongly and smoothly on the incident energy. This potential shows a transition from surface transparency to strong absorption as E/sub lab/ approaches 81 MeV. The ambiguities in the strengths of the potential are discussed. The broad dispersive potential resonances which are present in several partial waves at every energy are also discussed and their relative importance is examined.
Giant elastic tunability in strained BiFeO3 near an electrically induced phase transition
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Yu, Pu; Vasudevan, Rama K.; Tselev, Alexander; Xue, Fei; Chen, Long -Qing; Maksymovych, Petro; Kalinin, Sergei V.; Balke, Nina; Li, Q.; Cao, Y.; et al
2015-01-01
Elastic anomalies are signatures of phase transitions in condensed matters and have traditionally been studied using various techniques spanning from neutron scattering to static mechanical testing. Here, using band-excitation elastic/piezoresponse spectroscopy, we probed sub-MHz elastic dynamics of a tip bias-induced rhombohedral–tetragonal phase transition of strained (001)-BiFeO3 (rhombohedral) ferroelectric thin films from ~103 nm3 sample volumes. Near this transition, we observed that the Young's modulus intrinsically softens by over 30% coinciding with 2-3 folds enhancement of local piezoresponse. Coupled with phase-field modeling, we also addressed the influence of polarization switching and mesoscopic structural heterogeneities (e.g., domain walls) on the kinetics ofmore » this phase transition, thereby providing fresh insights into the morphotropic phase boundary (MPB) in ferroelectrics. Moreover, the giant electrically tunable elastic stiffness and corresponding electromechanical properties observed here suggest potential applications of BiFeO3 in next-generation frequency-agile electroacoustic devices, based on utilization of the soft modes underlying successive ferroelectric phase transitions.« less
Evolution of Elastic X-ray Scattering in Laser-Shocked Warm Dense Li
Kugland, N L; Gregori, G; Bandyopadhyay, S; Brenner, C; Brown, C; Constantin, C; Glenzer, S H; Khattak, F; Kritcher, A L; Niemann, C; Otten, A; Pasley, J; Pelka, A; Roth, M; Spindloe, C; Riley, D
2009-06-02
We have studied the dynamics of warm dense Li with near-elastic x-ray scattering. Li foils were heated and compressed using shock waves driven by 4 ns long laser pulses. Separate 1 ns long laser pulses were used to generate a bright source of 2.96 keV Cl Ly-{alpha} photons for x-ray scattering, and the spectrum of scattered photons was recorded at a scattering angle of 120{sup o} using a HOPG crystal operated in the von Hamos geometry. A variable delay between the heater and backlighter laser beams measured the scattering time evolution. Comparison with radiation hydrodynamics simulations shows that the plasma is highly coupled during the first several nanoseconds, then relaxes to a moderate coupling state at later times. Near-elastic scattering amplitudes have been successfully simulated using the screened one-component plasma model. Our main finding is that the near-elastic scattering amplitudes are quite sensitive to the mean ionization state {bar Z}, and by extension to the choice of ionization model in the radiation-hydrodynamics simulations used to predict plasma properties within the shocked Li.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
... Industry outreach: DOE and Wave Energy Scotland co-sponsored WEC technology workshop News, Partnership, Renewable Energy, Water Power, Workshops Industry outreach: DOE and Wave ...
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.
2015-12-24
Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs formore » large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.« less
Chang, G.; Ruehl, K.; Jones, C. A.; Roberts, J.; Chartrand, C.
2015-12-24
Modeled nearshore wave propagation was investigated downstream of simulated wave energy converters (WECs) to evaluate overall near- and far-field effects of WEC arrays. Model sensitivity to WEC characteristics and WEC array deployment scenarios was evaluated using a modified version of an industry standard wave model, Simulating WAves Nearshore (SWAN), which allows the incorporation of device-specific WEC characteristics to specify obstacle transmission. The sensitivity study illustrated that WEC device type and subsequently its size directly resulted in wave height variations in the lee of the WEC array. Wave heights decreased up to 30% between modeled scenarios with and without WECs for large arrays (100 devices) of relatively sizable devices (26 m in diameter) with peak power generation near to the modeled incident wave height. Other WEC types resulted in less than 15% differences in modeled wave height with and without WECs, with lesser influence for WECs less than 10 m in diameter. Wave directions and periods were largely insensitive to changes in parameters. Furthermore, additional model parameterization and analysis are required to fully explore the model sensitivity of peak wave period and mean wave direction to the varying of the parameters.
Expanding the World's Largest Database of Elastic Properties
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Expanding the World's Largest Database of Elastic Properties Expanding the World's Largest Database of Elastic Properties NERSC, Materials Project Help Scientists Increase Available Data Almost Ten-Fold April 7, 2015 Contact: Julie Chao, jchao@lbl.gov, 510.486.6491 Scientists at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) have published the world's largest set of data on the complete elastic properties of inorganic compounds, increasing by an order of
Elastic Scattering LIDAR Data Acquisition Visualization and Analysis
Energy Science and Technology Software Center (OSTI)
1999-10-12
ELASTIC/EVIEW is a software system that controls an elastic scattering atmospheric Light Detection and Ranging (LIDAR) instrument. It can acquire elastic scattering LIDAR data using this system and produce images of one, two, and three-dimensional atmospheric data on particulates and other atmospheric pollutants. The user interface is a modern menu driven syatem with appropriate support for user configuration and printing files.
An Analytical Elastic Plastic Contact Model with Strain Hardening...
Office of Scientific and Technical Information (OSTI)
Journal Article: An Analytical Elastic Plastic Contact Model with Strain Hardening and Frictional Effects for Normal and Oblique Impacts. Citation Details In-Document Search Title:...
High elastic modulus polymer electrolytes suitable for preventing...
Office of Scientific and Technical Information (OSTI)
electrolytes suitable for preventing thermal runaway in lithium batteries Citation Details In-Document Search Title: High elastic modulus polymer electrolytes suitable for ...
Elastic recoil detection analysis of 3He.
Doyle, Barney Lee; Knapp, James Arthur; Wampler, William R.; Banks, James Clifford; Arstila, Kai Atso
2003-08-01
We give the results of a study using Monte Carlo ion interaction codes to simulate and optimize elastic recoil detection analysis for {sup 3}He buildup in tritide films. Two different codes were used. The primary tool was MCERD, written especially for simulating ion beam analysis using optimizations and enhancements for greatly increasing the probabilities for the creation and the detection of recoil atoms. MPTRIM, an implementation of the TRIMRC code for a massively parallel computer, was also used for comparison and for determination of absolute yield. This study was undertaken because of a need for high-resolution depth profiling of 3He and near-surface light impurities (e.g. oxygen) in metal hydride films containing tritium.
Active Seismic Techniques | Open Energy Information
Technique: Seismic Techniques Information Provided by Technique Lithology: Rock unit density influences elastic wave velocities. StratigraphicStructural: Structural geology-...
Borehole Seismic Techniques | Open Energy Information
Technique: Downhole Techniques Information Provided by Technique Lithology: Rock unit density influences elastic wave velocities StratigraphicStructural: Structural geology-...
Vertical Seismic Profiling | Open Energy Information
Borehole Seismic Techniques Information Provided by Technique Lithology: Rock unit density influences elastic wave velocities. StratigraphicStructural: Structural geology-...
Teleseismic-Seismic Monitoring | Open Energy Information
Passive Seismic Techniques Information Provided by Technique Lithology: Rock unit density influences elastic wave velocities. StratigraphicStructural: Map geothermal...
On the grade consistent theories of micromorphic elastic solids
Iesan, D.
2011-02-10
For the investigation of specific nonlocal phenomena the second-order displacement gradient has been added to the independent constitutive variables used in the classical theories of elastic solids. In this paper we outline the hystorical development of the subject and present a nonlinear grade consistent theory of micromorphic elastic solids in which the independent constitutive variables are the deformation gradient, the second-order displacement gradient, microdeformation tensor, and microdeformation gradient. Then, we present the linearized theory and establish a uniqueness result with no definiteness assumption on the elastic coefficients. The theory is used to obtain the basic eqations of a grade consistent theory of microstretch elastic bodies. The field equations for an isotropic and homogeneous elastic body are presented. A counterpart of the Cauchy-Kowalevski-Somigliana solution of the classical elastodynamics is established.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Qi, Xintong; Wang, Xuebing; Chen, Ting; Li, Baosheng
2016-03-30
Compressional and shear wave velocities of the α phase of hafnium have been measured up to 10.4 GPa at room temperature using ultrasonic interferometry in a multi-anvil apparatus. A finite strain equation of state analysis yielded Ks0 = 110.4 (5) GPa, G0 = 54.7(5) GPa,Ks0' = 3.7 and G0' = 0.6 for the elastic bulk and shear moduli and their pressure derivatives at ambient conditions. Complementary to the experimental data, the single crystal elastic constants, elastic anisotropy and the unit cell axial ratio c/a of α-hafnium at high pressures were investigated by Density Functional Theory (DFT) based first principles calculations.more » A c/a value of 1.605 is predicted for α-Hf at 40 GPa, which is in excellent agreement with previous experimental results. The low-pressure derivative of the shear modulus observed in our experimental data up to 10 GPa was found to originate from the elastic constant C44 which exhibits negligible pressure dependence within the current experimental pressure range. At higher pressures (>10 GPa), C44 was predicted to soften and the shear wave velocity νS trended to decrease with pressure, which can be interpreted as a precursor to the α-ω transition similar to that observed in other group IV elements (titanium and zirconium). Here, the acoustic velocities, bulk and shear moduli, and the acoustic Debye temperature (θD = 240.1 K) determined from the current experiments were all compared well with those predicted by our theoretical DFT calculations.« less
Menikoff, Ralph
2015-12-14
The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.
Elastic modulus of phases in Ti–Mo alloys
Zhang, Wei-dong; Liu, Yong; Wu, Hong; Song, Min; Zhang, Tuo-yang; Lan, Xiao-dong; Yao, Tian-hang
2015-08-15
In this work, a series of binary Ti–Mo alloys with the Mo contents ranging from 3.2 to 12 at.% were prepared using non-consumable arc melting. The microstructures were investigated by X-ray diffraction and transmission electron microscope, and the elastic modulus was evaluated by nanoindentation testing technique. The evolution of the volume fractions of ω phase was investigated using X-ray photoelectron spectroscopy. The results indicated that the phase constitution and elastic modulus of the Ti–Mo alloys are sensitive to the Mo content. Ti–3.2Mo and Ti–8Mo alloys containing only α and β phases, respectively, have a low elastic modulus. In contrast, Ti–4.5Mo, Ti–6Mo, Ti–7Mo alloys, with different contents of ω phase, have a high elastic modulus. A simple micromechanical model was used to calculate the elastic modulus of ω phase (E{sub ω}), which was determined to be 174.354 GPa. - Highlights: • Ti–Mo alloys with the Mo contents ranging from 3.2 to 12 at.% were investigated. • XPS was used to investigate the volume fractions of ω phase. • The elastic modulus of Ti–Mo alloys is sensitive to the Mo content. • The elastic modulus of ω phase was determined to be 174.354 GPa.
Catching a Wave: Innovative Wave Energy Device Surfs for Power...
Office of Environmental Management (EM)
Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii July 29, 2015 - 12:00pm Addthis...
Interaction of a nonlinear spin-wave and magnetic soliton in a uniaxial anisotropic ferromagnet
Li Zaidong Li Qiuyan; He Pengbin; Bai Zhanguo; Sun Yubao
2007-12-15
We study the interaction of a nonlinear spin-wave and magnetic soliton in a uniaxial anisotropic ferromagnet. By means of a reasonable assumption and a straightforward Darboux transformation one- and two-soliton solutions in a nonlinear spin-wave background are obtained analytically, and their properties are discussed in detail. On the background of a nonlinear spin-wave the amplitude of the envelope soliton has the spatial and temporal period, and soliton can be trapped only in space. The amplitude and wave number of spin-wave have the different contribution to the width, velocity, and amplitude of soliton solutions. The envelope of solution hold the shape of soliton, and the amplitude of each envelope soliton keeps invariability before and after collision which shows the elastic collision of two envelope soliton on the background of a nonlinear spin-wave.
Elasticity of single-crystal olivine at high pressures and temperature...
Office of Scientific and Technical Information (OSTI)
Elasticity of single-crystal olivine at high pressures and temperatures Citation Details In-Document Search Title: Elasticity of single-crystal olivine at high pressures and ...
Martin, F.; Jaouen, C.; Pacaud, J.; Abadias, G.; Djemia, Ph.; Ganot, F.
2005-01-15
The interdependence between the microstructure of sputter-deposited Ni(111)/Mo(110) superlattices and their elastic behavior is investigated as a function of the bilayer period ({lambda}). Brillouin light scattering measurements show that a drastic softening of the effective shear modulus occurs with decreasing {lambda}, until {lambda}=2 nm where it reaches -62%. Ion irradiation is here used to trigger stress relaxation and to induce, in a controlled way, interdiffusion and structural changes allowing us thus to investigate their influence on the elastic anomaly. At a very low irradiation dose (0.1 displacements per atom), the relief of the lattice expansion and associated compressive stresses does not induce any change of the elastic response, which indicates that the elastic behavior of the as-grown multilayers is not correlated with the presence of elastic strains. Furthermore, a detailed x-ray diffraction analysis shows that the unstrained lattice parameter of Mo layers exhibit a linear dependence with the interface density, while the Ni unstrained lattice parameter remains nearly unchanged in the same {lambda} range. This effect can be attributed to an interfacial mixing of a constant Ni amount ({approx}1.5 monolayers) into the Mo layers, as a consequence of a dynamic segregation of Ni atoms during growth. Thus, the formation of interfacial metastable and supersaturated solid solutions, structurally and mechanically unstable, appears as the origin of the huge elastic softening observed in this system. At high ion fluences, when the mixing process becomes dominant, the present study also provides experimental data on phase transformation in 'driven' alloys, by addressing the issue of the stability of out-of-equilibrium structures under irradiation.
Elastic properties of gamma-Pu by resonant ultrasound spectroscopy
Migliori, Albert; Betts, J; Trugman, A; Mielke, C H; Mitchell, J N; Ramos, M; Stroe, I
2009-01-01
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.
Wave Energy | Open Energy Information
Wave Energy Jump to: navigation, search Contents 1 Description 2 History 3 Technology 4 Current and Possible Wave Farms 5 Pros and Cons Description Wave energy (or wave power) is...
Ultra Deep Wave Equation Imaging and Illumination
Alexander M. Popovici; Sergey Fomel; Paul Sava; Sean Crawley; Yining Li; Cristian Lupascu
2006-09-30
In this project we developed and tested a novel technology, designed to enhance seismic resolution and imaging of ultra-deep complex geologic structures by using state-of-the-art wave-equation depth migration and wave-equation velocity model building technology for deeper data penetration and recovery, steeper dip and ultra-deep structure imaging, accurate velocity estimation for imaging and pore pressure prediction and accurate illumination and amplitude processing for extending the AVO prediction window. Ultra-deep wave-equation imaging provides greater resolution and accuracy under complex geologic structures where energy multipathing occurs, than what can be accomplished today with standard imaging technology. The objective of the research effort was to examine the feasibility of imaging ultra-deep structures onshore and offshore, by using (1) wave-equation migration, (2) angle-gathers velocity model building, and (3) wave-equation illumination and amplitude compensation. The effort consisted of answering critical technical questions that determine the feasibility of the proposed methodology, testing the theory on synthetic data, and finally applying the technology for imaging ultra-deep real data. Some of the questions answered by this research addressed: (1) the handling of true amplitudes in the downward continuation and imaging algorithm and the preservation of the amplitude with offset or amplitude with angle information required for AVO studies, (2) the effect of several imaging conditions on amplitudes, (3) non-elastic attenuation and approaches for recovering the amplitude and frequency, (4) the effect of aperture and illumination on imaging steep dips and on discriminating the velocities in the ultra-deep structures. All these effects were incorporated in the final imaging step of a real data set acquired specifically to address ultra-deep imaging issues, with large offsets (12,500 m) and long recording time (20 s).
Nefkens, B.M.K.; Barlow, D.B.; Kessler, R.S.; Kim, G.J.; Pillai, C.; Price, J.W.; Wightman, J.A.; Hall, S.; Lane, D.W.; Loe, S.R.; and others
1988-11-20
The verification of the existing sets of ..pi..N scattering phases is sought via the determination of the A and R spin rotation parameters in ..pi../sup +/p and ..pi../sup -/p elastic scattering. The preliminary results of this first measurement of these parameters for incident pion momenta from 427 to 657 MeV/c, show agreement with the gross features of the partial-wave analyses by the groups from VPI, Karlsruhe-Helsinki, and Carnegie-Mellon-LBL. There is room for improvement.
Elastic-Waveform Inversion with Compressive Sensing for Sparse Seismic Data
Lin, Youzuo; Huang, Lianjie
2015-01-26
Accurate velocity models of compressional- and shear-waves are essential for geothermal reservoir characterization and microseismic imaging. Elastic-waveform inversion of multi-component seismic data can provide high-resolution inversion results of subsurface geophysical properties. However, the method requires seismic data acquired using dense source and receiver arrays. In practice, seismic sources and/or geophones are often sparsely distributed on the surface and/or in a borehole, such as 3D vertical seismic profiling (VSP) surveys. We develop a novel elastic-waveform inversion method with compressive sensing for inversion of sparse seismic data. We employ an alternating-minimization algorithm to solve the optimization problem of our new waveform inversion method. We validate our new method using synthetic VSP data for a geophysical model built using geologic features found at the Raft River enhanced-geothermal-system (EGS) field. We apply our method to synthetic VSP data with a sparse source array and compare the results with those obtained with a dense source array. Our numerical results demonstrate that the velocity mode ls produced with our new method using a sparse source array are almost as accurate as those obtained using a dense source array.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Mchedlishvili, D.; Chiladze, D.; Dymov, S.; Bagdasarian, Z.; Barsov, S.; Gebel, R.; Gou, B.; Hartmann, M.; Kacharava, A.; Keshelashvili, I.; et al
2016-02-03
The differential cross section for proton-proton elastic scattering has been measured at a beam kinetic energy of 1.0 GeV and in 200 MeV steps from 1.6 to 2.8 GeV for centre-of-mass angles in the range from 12°-16° to 25°-30°, depending on the energy. A precision in the overall normalisation of typically 3% was achieved by studying the energy losses of the circulating beam of the COSY storage ring as it passed repeatedly through the windowless hydrogen target of the ANKE magnetic spectrometer. It is shown that the data have a significant impact upon the results of a partial wave analysis.more » Furthermore, after extrapolating the differential cross sections to the forward direction, the results are broadly compatible with the predictions of forward dispersion relations.« less
Metamaterials-based sensor to detect and locate nonlinear elastic sources
Gliozzi, Antonio S.; Scalerandi, Marco; Miniaci, Marco; Bosia, Federico; Pugno, Nicola M.
2015-10-19
In recent years, acoustic metamaterials have attracted increasing scientific interest for very diverse technological applications ranging from sound abatement to ultrasonic imaging, mainly due to their ability to act as band-stop filters. At the same time, the concept of chaotic cavities has been recently proposed as an efficient tool to enhance the quality of nonlinear signal analysis, particularly in the ultrasonic/acoustic case. The goal of the present paper is to merge the two concepts in order to propose a metamaterial-based device that can be used as a natural and selective linear filter for the detection of signals resulting from the propagation of elastic waves in nonlinear materials, e.g., in the presence of damage, and as a detector for the damage itself in time reversal experiments. Numerical simulations demonstrate the feasibility of the approach and the potential of the device in providing improved signal-to-noise ratios and enhanced focusing on the defect locations.
Determination of Elastic Twist in Horizontal Axis Wind Turbines (HAWTs)
Stoddard, F.; Nelson, V.; Starcher, K.; Andrews, B.
2006-06-01
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.
Expanding the World's Largest Database of Elastic Properties
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
looking at how the process can be accelerated even more. "We want to use statistical learning to extract information to build predictive models in order to predict the elastic...
Imaging shock waves in diamond with both high temporal and spatial resolution at an XFEL
Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.
2015-06-18
The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.
Elastic-plastic response charts for nuclear overpressures. Final report
Guice, L.K.; Kiger, S.A.
1984-06-01
The single-degree-of-freedom equation of motion for an elastic-plastic system with forcing functions that are representative of nuclear weapon simulations is nondimensionalized and solved. Numerical solutions are calculated by the Newmark Beta method, and response charts incorporating nondimensionalized structural and loading parameters for the Speicher-Brode nuclear pressure history description are provided. A computer code is presented for solving the elastic-plastic problem for Speicher-Brode overpressure as well as triangular-shaped overpressures.
Microsoft Word - Fuel Substitution Elasticities final.docx
Gasoline and Diesel Fuel Update (EIA)
Fuel Competition in Power Generation and Elasticities of Substitution June 2012 Independent Statistics & Analysis www.eia.gov U.S. Department of Energy Washington, DC 20585 U.S. Energy Information Administration | Fuel Competition in Power Generation and Elasticities of Substitution i This report was prepared by the U.S. Energy Information Administration (EIA), the statistical and analytical agency within the U.S. Department of Energy. By law, EIA's data, analyses, and forecasts are
Cycloidal Wave Energy Converter
Stefan G. Siegel, Ph.D.
2012-11-30
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
Giant elastic tunability in strained BiFeO_{3} near an electrically induced phase transition
Yu, Pu; Vasudevan, Rama K.; Tselev, Alexander; Xue, Fei; Chen, Long -Qing; Maksymovych, Petro; Kalinin, Sergei V.; Balke, Nina; Li, Q.; Cao, Y.; Laanait, N.
2015-01-01
Elastic anomalies are signatures of phase transitions in condensed matters and have traditionally been studied using various techniques spanning from neutron scattering to static mechanical testing. Here, using band-excitation elastic/piezoresponse spectroscopy, we probed sub-MHz elastic dynamics of a tip bias-induced rhombohedral–tetragonal phase transition of strained (001)-BiFeO_{3} (rhombohedral) ferroelectric thin films from ~10^{3} nm^{3} sample volumes. Near this transition, we observed that the Young's modulus intrinsically softens by over 30% coinciding with 2-3 folds enhancement of local piezoresponse. Coupled with phase-field modeling, we also addressed the influence of polarization switching and mesoscopic structural heterogeneities (e.g., domain walls) on the kinetics of this phase transition, thereby providing fresh insights into the morphotropic phase boundary (MPB) in ferroelectrics. Moreover, the giant electrically tunable elastic stiffness and corresponding electromechanical properties observed here suggest potential applications of BiFeO_{3} in next-generation frequency-agile electroacoustic devices, based on utilization of the soft modes underlying successive ferroelectric phase transitions.
Measurement of np elastic scattering spin-spin correlation parameters at 484, 634, and 788 MeV
Garnett, R.W.
1989-03-01
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.
Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; et al
2015-01-01
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 (Hmore » 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« less
Influence of interstitial Mn on magnetism in room-temperature ferromagnet Mn(1+delta)Sb
Taylor, Alice E; Berlijn, Tom; Hahn, Steven E; May, Andrew F; Williams, Travis J; Poudel, Lekhanath N; Calder, Stuart A; Fishman, Randy Scott; Stone, Matthew B; Aczel, Adam A; Cao, Huibo; Lumsden, Mark D; Christianson, Andrew D
2015-01-01
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
Pore-fluid effects on seismic waves in vertically fractured earth with orthotropic symmetry
Berryman, J.G.
2010-05-15
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.
Wouters, L.F.
1960-08-30
Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.
Dong, Bing; Zhou, Xiao-Lin E-mail: lkworld@126.com; Chang, Jing; Liu, Ke E-mail: lkworld@126.com
2014-08-07
The structural and elastic properties of RuN{sub 2} were investigated through the first-principles calculation using generalized gradient approximation (GGA) and local density approximation (LDA) within the plane-wave pseudopotential density functional theory. The obtained equilibrium structure and mechanical properties are in excellent agreement with other theoretical results. Then we compared the elastic modulus of RuN{sub 2} with several other isomorphic noble metal nitrides. Results show that RuN{sub 2} can nearly rival with OsN{sub 2} and IrN{sub 2}, which indicate RuN{sub 2} is a potentially ultra-incompressible and hard material. By the elastic stability criteria, it is predicted that RuN{sub 2} is stable in our calculations (0–100 GPa). The calculated B/G ratios indicate that RuN{sub 2} possesses brittle nature at 0 GPa and when the pressure increases to 13.4 GPa (for LDA) or 20.8 GPa (for GGA), it begins to prone to ductility. Through the quasi-harmonic Debye model, we also investigated the thermodynamic properties of RuN{sub 2}.
Oblique solitary waves in a five component plasma
Sijo, S.; Manesh, M.; Sreekala, G.; Venugopal, C.; Neethu, T. W.; Renuka, G.
2015-12-15
We investigate the influence of a second electron component on oblique dust ion acoustic solitary waves in a five component plasma consisting of positively and negatively charged dust, hydrogen ions, and hotter and colder electrons. Of these, the heavier dust and colder photo-electrons are of cometary origin while the other two are of solar origin; electron components are described by kappa distributions. The K-dV equation is derived, and different attributes of the soliton such as amplitude and width are plotted for parameters relevant to comet Halley. We find that the second electron component has a profound influence on the solitary wave, decreasing both its amplitude and width. The normalized hydrogen density strongly influences the solitary wave by decreasing its width; the amplitude of the solitary wave, however, increases with increasing solar electron temperatures.
Hydrogen, Deuterium and Tritium in Palladium: An Elastic Constants Study
Bach, H.T.; Schwarz, R.B.; Tuggle, D.G.
2005-07-15
We have used resonant ultrasound spectroscopy to measure the three independent elastic constants of Pd-H, Pd-D, and Pd-T single crystal at 300K as a function of hydrogen, deuterium, and tritium concentration, respectively. The addition of interstitial H (D, or T) atoms, located at (0,1/2,0) in the fcc Pd lattice, affects all three elastic constants C', C{sub 44}, and B. In the mixed ({alpha}+{beta}) phase, and with increasing H isotope, the shear modulus C' shows an abnormal softening whereas C{sub 44} and B do not. This is explained in terms of Zener-type an elastic relaxations affecting the shape of the hydride phases in the coherent({alpha}+{beta}) two-phase mixture In the single {beta}-phase, C' shows a strong isotope dependence whereas C{sub 44} and B show none. This behavior is explained in terms of differences in the excitation of optical phonons. In Pd-T, {sup 3}He is produced by the radioactive decay of tritium. We have measured in situ the swelling and the change in the elastic constants in Pd-T as a function of aging time. Aging ({sup 3}He formation) affects all three elastic constants. These measurements are being used to understand the early stages of {sup 3}H-{sup 3}He cluster formation in aged Pd-T crystal.
Price-elastic demand in deregulated electricity markets
Siddiqui, Afzal S.
2003-05-01
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.
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.
Leavitt, M.A.; Lutz, I.C.
1958-08-01
An amplifier circuit is described for amplifying sigmals having an alternating current component superimposed upon a direct current component, without loss of any segnnent of the alternating current component. The general circuit arrangement includes a vibrator, two square wave amplifiers, and recombination means. The amplifier input is connected to the vibrating element of the vibrator and is thereby alternately applied to the input of each square wave amplifier. The detailed circuitry of the recombination means constitutes the novelty of the annplifier and consists of a separate, dual triode amplifier coupled to the output of each square wave amplifier with a recombination connection from the plate of one amplifier section to a grid of one section of the other amplifier. The recombination circuit has provisions for correcting distortion caused by overlapping of the two square wave voltages from the square wave amplifiers.
Wave induced density modification in RF sheaths and close to wave launchers
Van Eester, D.; Lu, Ling-Feng
2015-12-10
With the return to full metal walls - a necessary step towards viable fusion machines - and due to the high power densities of current-day ICRH (Ion Cyclotron Resonance Heating) or RF (radio frequency) antennas, there is ample renewed interest in exploring the reasons for wave-induced sputtering and formation of hot spots. Moreover, there is experimental evidence on various machines that RF waves influence the density profile close to the wave launchers so that waves indirectly influence their own coupling efficiency. The present study presents a return to first principles and describes the wave-particle interaction using a 2-time scale model involving the equation of motion, the continuity equation and the wave equation on each of the time scales. Through the changing density pattern, the fast time scale dynamics is affected by the slow time scale events. In turn, the slow time scale density and flows are modified by the presence of the RF waves through quasilinear terms. Although finite zero order flows are identified, the usual cold plasma dielectric tensor - ignoring such flows - is adopted as a first approximation to describe the wave response to the RF driver. The resulting set of equations is composed of linear and nonlinear equations and is tackled in 1D in the present paper. Whereas the former can be solved using standard numerical techniques, the latter require special handling. At the price of multiple iterations, a simple ’derivative switch-on’ procedure allows to reformulate the nonlinear problem as a sequence of linear problems. Analytical expressions allow a first crude assessment - revealing that the ponderomotive potential plays a role similar to that of the electrostatic potential arising from charge separation - but numerical implementation is required to get a feeling of the full dynamics. A few tentative examples are provided to illustrate the phenomena involved.
First-principles elastic properties of (alpha)-Pu
Soderlind, P; Klepeis, J E
2008-11-04
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.
A robust absorbing layer method for anisotropic seismic wave modeling
Mtivier, L.; Brossier, R.; Labb, S.; Operto, S.; Virieux, J.
2014-12-15
When applied to wave propagation modeling in anisotropic media, Perfectly Matched Layers (PML) exhibit instabilities. Incoming waves are amplified instead of being absorbed. Overcoming this difficulty is crucial as in many seismic imaging applications, accounting accurately for the subsurface anisotropy is mandatory. In this study, we present the SMART layer method as an alternative to PML approach. This method is based on the decomposition of the wavefield into components propagating inward and outward the domain of interest. Only outgoing components are damped. We show that for elastic and acoustic wave propagation in Transverse Isotropic media, the SMART layer is unconditionally dissipative: no amplification of the wavefield is possible. The SMART layers are not perfectly matched, therefore less accurate than conventional PML. However, a reasonable increase of the layer size yields an accuracy similar to PML. Finally, we illustrate that the selective damping strategy on which is based the SMART method can prevent the generation of spurious S-waves by embedding the source in a small zone where only S-waves are damped.
Ghosh, G.
2015-08-15
A comprehensive computational study of elastic properties of cementite (Fe{sub 3}C) and its alloyed counterparts (M{sub 3}C (M = Al, Co, Cr, Cu, Fe, Hf, Mn, Mo, Nb, Ni, Si, Ta, Ti, V, W, Zr, Cr{sub 2}FeC and CrFe{sub 2}C) having the crystal structure of Fe{sub 3}C is carried out employing electronic density-functional theory (DFT), all-electron PAW pseudopotentials and the generalized gradient approximation for the exchange-correlation energy (GGA). Specifically, as a part of our systematic study of cohesive properties of solids and in the spirit of materials genome, following properties are calculated: (i) single-crystal elastic constants, C{sub ij}, of above M{sub 3}Cs; (ii) anisotropies of bulk, Young’s and shear moduli, and Poisson’s ratio based on calculated C{sub ij}s, demonstrating their extreme anisotropies; (iii) isotropic (polycrystalline) elastic moduli (bulk, shear, Young’s moduli and Poisson’s ratio) of M{sub 3}Cs by homogenization of calculated C{sub ij}s; and (iv) acoustic Debye temperature, θ{sub D}, of M{sub 3}Cs based on calculated C{sub ij}s. We provide a critical appraisal of available data of polycrystalline elastic properties of alloyed cementite. Calculated single crystal properties may be incorporated in anisotropic constitutive models to develop and test microstructure-processing-property-performance links in multi-phase materials where cementite is a constituent phase.
Wave-wave interactions in solar type III radio bursts
Thejappa, G.; MacDowall, R. J.
2014-02-11
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.
Studying the proton 'radius' puzzle with ?p elastic scattering
Gilman, R.
2013-11-07
The disagreement between the proton radius determined from muonic hydrogen and from electronic measurements is called the proton radius puzzle. The resolution of the puzzle remains unclear and appears to require new experimental results. An experiment to measure muon-proton elastic scattering is presented here.
Hietala, Vincent M.; Vawter, Gregory A.
1993-01-01
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.
Hietala, V.M.; Vawter, G.A.
1993-12-14
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.
Weinstein, Alla
2011-11-01
Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.
Quasi-Rayleigh waves in butt-welded thick steel plate
Kamas, Tuncay E-mail: victorg@sc.edu Giurgiutiu, Victor E-mail: victorg@sc.edu Lin, Bin E-mail: victorg@sc.edu
2015-03-31
This paper discusses theoretical and experimental analyses of weld guided surface acoustic waves (SAW) through the guided wave propagation (GWP) analyses. The GWP analyses have been carried out by utilizing piezoelectric wafer active sensors (PWAS) for in situ structural inspection of a thick steel plate with butt weld as the weld bead is ground flush. Ultrasonic techniques are commonly used for validation of welded structures in many in-situ monitoring applications, e.g. in off-shore structures, in nuclear and pressure vessel industries and in a range of naval applications. PWAS is recently employed in such ultrasonic applications as a resonator as well as a transducer. Quasi-Rayleigh waves a.k.a. SAW can be generated in relatively thick isotropic elastic plate having the same phase velocity as Rayleigh waves whereas Rayleigh waves are a high frequency approximation of the first symmetric (S0) and anti-symmetric (A0) Lamb wave modes. As the frequency becomes very high the S0 and the A0 wave speeds coalesce, and both have the same value. This value is exactly the Rayleigh wave speed and becomes constant along the frequency i.e. Rayleigh waves are non-dispersive guided surface acoustic waves. The study is followed with weld-GWP tests through the pitch-catch method along the butt weld line. The tuning curves of quasi-Rayleigh wave are determined to show the tuning and trapping effect of the weld bead that has higher thickness than the adjacent plates on producing a dominant quasi-Rayleigh wave mode. The significant usage of the weld tuned and guided quasi-Rayleigh wave mode is essentially discussed for the applications in the in-situ inspection of relatively thick structures with butt weld such as naval offshore structures. The paper ends with summary, conclusions and suggestions for future work.
Wave propagation in an epoxy-graphite laminate
Clements, B.E.; Johnson, J.N.; Addessio, F.L.
1997-11-01
The third-order, nonhomogenized, dynamic method of cells is used to calculate the particle velocity for a shock wave experiment involving an epoxy{endash}graphite laminate. Constitutive relations suitable for the various materials are used. This includes linear and nonlinear elasticity and, when appropriate, viscoelasticity. It is found to be beneficial to incorporate artificial viscosity into the analysis. Artificial viscosity successfully removes the unphysical high-frequency ringing in the numerical solutions of the theory, while leaving the physical oscillations, characteristic of wave propagation in a periodic laminate, largely undiminished. It also allows the viscoelastic relaxed moduli to be closer to their unrelaxed counterparts than in a previous calculation, thus making them more acceptable. The results agree well with the corresponding plate-impact experiment, and are compared to the second-order theory of Clements, Johnson, and Hixson [Phys. Rev. E, {bold 54}, 6876 (1996)]. {copyright} {ital 1997 American Institute of Physics.}
Energy Science and Technology Software Center (OSTI)
2007-01-08
WPP is a massively parallel, 3D, C++, finite-difference elastodynamic wave propagation code. Typical applications for wave propagation with WPP include: evaluation of seismic event scenarios and damage from earthquakes, non-destructive evaluation of materials, underground facility detection, oil and gas exploration, predicting the electro-magnetic fields in accelerators, and acoustic noise generation. For more information, see Users Manual [1].
Gravitational Waves Community Lecture
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Gravitational Waves Community Lecture Gravitational Waves Community Lecture WHEN: Sep 19, 2016 7:30 PM - 8:30 PM WHERE: Grand Ballroom at the Eldorado Hotel 309 W San Francisco St Santa Fe, New Mexico 87501 USA (505) 988-4455 SPEAKER: Gabriela Gonzalez CONTACT: Linda Anderman (505) 665-9196 CATEGORY: Bradbury INTERNAL: Calendar Login Event Description Sponsored by Los Alamos National Laboratory, University of New Mexico, St. John's College and Santa Fe Community College The Los Alamos National
Internal energy relaxation in shock wave structure
Josyula, Eswar Suchyta, Casimir J.; Boyd, Iain D.; Vedula, Prakash
2013-12-15
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.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Osti, Naresh C.; Mamontov, Eugene; Ramirez-cuesta, A.; Wesolowski, David J.; Diallo, S. O.
2015-12-10
Understanding the molecular behavior of water in spatially restricted environments is important to better understanding its role in many biological, chemical and geological processes. Here we examine the translational diffusion of water confined to a variety of substrates, from flat surfaces to nanoporous media, in the context of a recently proposed universal scaling law (Chiavazzo 2014) [1]. Using over a dozen previous neutron scattering results, we test the validity of this law, evaluating separately the influence of the hydration amount, and the effects of the size and morphology of the confining medium. Additionally, we investigate the effects of changing instrumentmore » resolutions and fitting models on the applicability of this law. Finally, we perform quasi-elastic neutron scattering measurements on water confined inside nanoporous silica to further evaluate this predictive law, in the temperature range 250≤T≤290 K.« less
Osti, Naresh C.; Mamontov, Eugene; Ramirez-cuesta, A.; Wesolowski, David J.; Diallo, S. O.
2015-12-10
Understanding the molecular behavior of water in spatially restricted environments is important to better understanding its role in many biological, chemical and geological processes. Here we examine the translational diffusion of water confined to a variety of substrates, from flat surfaces to nanoporous media, in the context of a recently proposed universal scaling law (Chiavazzo 2014) [1]. Using over a dozen previous neutron scattering results, we test the validity of this law, evaluating separately the influence of the hydration amount, and the effects of the size and morphology of the confining medium. Additionally, we investigate the effects of changing instrument resolutions and fitting models on the applicability of this law. Finally, we perform quasi-elastic neutron scattering measurements on water confined inside nanoporous silica to further evaluate this predictive law, in the temperature range 250≤T≤290 K.
Single-Crystal Elasticity of the Deep-Mantle Magnesite at High...
Office of Scientific and Technical Information (OSTI)
Journal Article: Single-Crystal Elasticity of the Deep-Mantle Magnesite at High Pressure and Temperature Citation Details In-Document Search Title: Single-Crystal Elasticity of the ...
Laser generation and detection of longitudinal and shear acoustic waves in a diamond anvil cell
Chigarev, Nikolay; Zinin, Pavel; Ming Lichung; Amulele, George; Bulou, Alain; Gusev, Vitalyi
2008-11-03
Laser ultrasonics in a point-source-point-receiver configuration is applied for the evaluation of elastic properties of nontransparent materials in a diamond anvil cell at high pressures. Measurement of both longitudinal and shear acoustic wave velocities in an iron foil at pressures up to 23 GPa does not require any information in addition to the one obtained by all-optical pump-probe technique.
Adler, Thomas A.
1996-01-01
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.
Measurements of the Influence of Acceleration and Temperature of Bodies on their Weight
Dmitriev, Alexander L.
2008-01-21
A brief review of experimental research of the influence of acceleration and temperatures of test mass upon gravitation force, executed between the 1990s and the beginning of 2000 at the St.-Petersburg State University of Information Technologies, Mechanics and Optics in cooperation with D. I. Mendeleev's Institute of Metrology is provided. According to a phenomenological notion, the acceleration of a test mass caused by external action, for example electromagnetic forces, results in changes of the gravitational properties of this mass. Consequences are a dependence upon gravity on the size and sign of test mass acceleration, and also on its absolute temperature. Results of weighing a rotor of a mechanical gyroscope with a horizontal axis, an anisotropic crystal with the big difference of the speed of longitudinal acoustic waves, measurements of temperature dependence of weight of metal bars of nonmagnetic materials, and also measurement of restitution coefficients at quasi-elastic impact of a steel ball about a massive plate are given. In particular, a reduction of apparent mass of a horizontal rotor with relative size 3.10{sup -6} at a speed of rotation of 18.6 thousand rev/min was observed. A negative temperature dependence of the weight of a brass core with relative size near 5.10{sup -4} K{sup -1} at room temperature was measured; this temperature factor was found to be a maximum for light and elastic metals. All observably experimental effects, have probably a general physical reason connected with the weight change dependent upon acceleration of a body or at thermal movement of its microparticles. The reduction of mass at high temperatures is of particular interest for propulsion applications.
Inelastic processes in seismic wave generation by underground explosions
Rodean, H.C.
1980-08-01
Theories, computer calculations, and measurements of spherical stress waves from explosions are described and compared, with emphasis on the transition from inelastic to almost-elastic relations between stress and strain. Two aspects of nonspherical explosion geometry are considered: tectonic strain release and surface spall. Tectonic strain release affects the generation of surface waves; spall closure may also. The reduced-displacement potential is a common solution (the equivalent elastic source) of the forward and inverse problems, assuming a spherical source. Measured reduced-displacement potentials are compared with potentials calculated as solutions of the direct and inverse problems; there are significant differences between the results of the two types of calculations and between calculations and measurements. The simple spherical model of an explosion is not sufficient to account for observations of explosions over wide ranges of depth and yield. The explosion environment can have a large effect on explosion detection and yield estimation. The best sets of seismic observations for use in developing discrimination techniques are for high-magnitude high-yield explosions; the identification problem is most difficult for low-magnitude low-yield explosions. Most of the presently available explosion data (time, medium, depth, yield, etc.) are for explosions in a few media at the Nevada Test Site; some key questions concerning magnitude vs yield and m/sub b/ vs M/sub s/ relations can be answered only by data for explosions in other media at other locations.
A new paradigm for the molecular basis of rubber elasticity
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hanson, David E.; Barber, John L.
2015-02-19
The molecular basis for rubber elasticity is arguably the oldest and one of the most important questions in the field of polymer physics. The theoretical investigation of rubber elasticity began in earnest almost a century ago with the development of analytic thermodynamic models, based on simple, highly-symmetric configurations of so-called Gaussian chains, i.e. polymer chains that obey Markov statistics. Numerous theories have been proposed over the past 90 years based on the ansatz that the elastic force for individual network chains arises from the entropy change associated with the distribution of end-to-end distances of a free polymer chain. There aremore » serious philosophical objections to this assumption and others, such as the assumption that all network nodes undergo affine motion and that all of the network chains have the same length. Recently, a new paradigm for elasticity in rubber networks has been proposed that is based on mechanisms that originate at the molecular level. Using conventional statistical mechanics analyses, quantum chemistry, and molecular dynamics simulations, the fundamental entropic and enthalpic chain extension forces for polyisoprene (natural rubber) have been determined, along with estimates for the basic force constants. Concurrently, the complex morphology of natural rubber networks (the joint probability density distributions that relate the chain end-to-end distance to its contour length) has also been captured in a numerical model. When molecular chain forces are merged with the network structure in this model, it is possible to study the mechanical response to tensile and compressive strains of a representative volume element of a polymer network. As strain is imposed on a network, pathways of connected taut chains, that completely span the network along strain axis, emerge. Although these chains represent only a few percent of the total, they account for nearly all of the elastic stress at high strain. Here we provide
Theoretical study of plasma effect on a conical shock wave
Kuo, S.P.; Kuo, Steven S.
2006-03-15
Experiments conducted previously in a Mach 2.5 wind tunnel showed that localized plasma generated by an on-board 60 Hz electric discharge in front of a 60 deg. cone-shaped model considerably increases the shock angle of the attached shock generated by the cone model. Based on the measured power and cycle energy of the electric discharge, the estimated peak and average temperature enhancements were too low to justify the heating effect as a possible cause of the observed shock wave modification. In this work, a theory also using a cone model as the shock wave generator is presented to explain the observed plasma effect on the shock wave. Through electron-neutral elastic collisions and ion-neutral charge transfer collisions, plasma generated in front of the baseline shock front can deflect the incoming flow before it reaches the cone model; such a flow deflection modifies the structure of the shock wave generated by the cone model from a conic shape to a slightly curved one. The shock remains to be attached to the tip of the cone; however, the shock front moves upstream to increase the shock angle, consistent with the experimental results.
Byers, Loren W.; Ten Cate, James A.; Johnson, Paul A.
2012-06-28
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.
Yerganian, Simon Scott
2003-02-11
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
2001-07-17
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.
Tuck, J.L.
1955-03-01
This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.
Lucas, Timothy S.
1991-01-01
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.
Precision Measurements of the Proton Elastic Form Factor Ratio
Douglas Higinbotham
2010-08-01
New high precision polarization measurements of the proton elastic form factor ratio in the Q^2 from 0.3 to 0.7 [GeV/c]^2 have been made. These elastic H(e,e'p) measurementswere done in Jefferson Lab's Hall A using 80% longitudinally polarized electrons and recoil polarimetry. For Q^2 greater than 1 [GeV/c]^2, previous polarization data indicated a strong deviation of the form factor ratio from unity which sparked renewed theoretical and experimental interest in how two-photon diagrams have been taken into account. The new high precision data indicate that the deviation from unity, while small, persists even at Q^2 less than 1 [GeV/c]^2.
Measurement of neutrino flux from neutrino-electron elastic scattering
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Park, J.; Aliaga, L.; Altinok, O.; Bellantoni, L.; Bercellie, A.; Betancourt, M.; Bodek, A.; Bravar, A.; Budd, H.; Cai, T.; et al
2016-06-10
In muon-neutrino elastic scattering on electrons is an observable neutrino process whose cross section is precisely known. Consequently a measurement of this process in an accelerator-based νμ beam can improve the knowledge of the absolute neutrino flux impinging upon the detector; typically this knowledge is limited to ~10% due to uncertainties in hadron production and focusing. We also isolated a sample of 135±17 neutrino-electron elastic scattering candidates in the segmented scintillator detector of MINERvA, after subtracting backgrounds and correcting for efficiency. We show how this sample can be used to reduce the total uncertainty on the NuMI νμ flux frommore » 9% to 6%. Finally, our measurement provides a flux constraint that is useful to other experiments using the NuMI beam, and this technique is applicable to future neutrino beams operating at multi-GeV energies.« less
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.
2015-03-17
The tensile behavior of a Ni₆₀Nb₄₀ 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
Elastic properties of Pu metal and Pu-Ga alloys
Soderlind, P; Landa, A; Klepeis, J E; Suzuki, Y; Migliori, A
2010-01-05
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.
Deformable elastic network refinement for low-resolution macromolecular crystallography
Schrder, Gunnar F.; Levitt, Michael; Brunger, Axel T.
2014-09-01
An overview of applications of the deformable elastic network (DEN) refinement method is presented together with recommendations for its optimal usage. Crystals of membrane proteins and protein complexes often diffract to low resolution owing to their intrinsic molecular flexibility, heterogeneity or the mosaic spread of micro-domains. At low resolution, the building and refinement of atomic models is a more challenging task. The deformable elastic network (DEN) refinement method developed previously has been instrumental in the determinion of several structures at low resolution. Here, DEN refinement is reviewed, recommendations for its optimal usage are provided and its limitations are discussed. Representative examples of the application of DEN refinement to challenging cases of refinement at low resolution are presented. These cases include soluble as well as membrane proteins determined at limiting resolutions ranging from 3 to 7 . Potential extensions of the DEN refinement technique and future perspectives for the interpretation of low-resolution crystal structures are also discussed.
Hardness, elastic, and electronic properties of chromium monoboride
Han, Lei; Wang, Shanmin; Zhu, Jinlong; Han, Songbai; Li, Wenmin; Chen, Bijuan; Wang, Xiancheng; Yu, Xiaohui E-mail: liubc@jlu.edu.cn Long, Youwen; Cheng, Jinguang; Jin, Changqing; Liu, Baochang E-mail: liubc@jlu.edu.cn; Zhang, Ruifeng E-mail: liubc@jlu.edu.cn; Zhang, Jianzhong; Zhao, Yusheng
2015-06-01
We report high-pressure synthesis of chromium monoboride (CrB) at 6 GPa and 1400 K. The elastic and plastic behaviors have been investigated by hydrostatic compression experiment and micro-indentation measurement. CrB is elastically incompressible with a high bulk modulus of 269.0 (5.9) GPa and exhibits a high Vickers hardness of 19.6 (0.7) GPa under the load of 1 kg force. Based on first principles calculations, the observed mechanical properties are attributed to the polar covalent Cr-B bonds interconnected with strong zigzag B-B covalent bonding network. The presence of metallic Cr bilayers is presumably responsible for the weakest paths in shear deformation.
Barrier distribution of quasi-elastic backward scattering
Mitsuoka, S.; Ikezoe, H.; Nishio, K.; Watanabe, Y.; Jeong, S. C.; Ishiyama, H.; Hirayama, Y.; Imai, N.; Miyatake, H.
2009-05-04
In order to study the nucleus-nucleus interaction in Pb-based cold fusion, we have measured excitation functions for quasi-elastic scattering of {sup 48}Ti, {sup 54}Cr, {sup 56}Fe, {sup 64}Ni, {sup 70}Zn and {sup 86}Kr projectiles on {sup 208}Pb target at backward angles. The barrier distributions were derived from the first derivative of measured quasi-elastic scattering cross sections relative to the Rutherford scattering cross section. The centroids of the barrier distributions show a deviation from several predicted barrier heights toward the low energy side. The shape of the barrier distributions is well reproduced by the results of a coupled-channel calculation taking account of the coupling effects of two phonon excitations of the quadrupole vibration for the projectiles and of the octupole vibration for the {sup 208}Pb target.
Atomic picture of elastic deformation in a metallic glass
Wang, X. D.; Aryal, S.; Zhong, C.; Ching, W. Y.; Sheng, H. W.; Zhang, H.; Zhang, D. X.; Cao, Q. P.; Jiang, J. Z.
2015-03-17
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, mainly caused by inhomogeneous distribution of excess volumes in the form of newly formed subatomic cavities.
Adaptive multiconfigurational wave functions
Evangelista, Francesco A.
2014-03-28
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.
Elastic-plastic analysis of the SS-3 tensile specimen
Majumdar, S.
1998-09-01
Tensile tests of most irradiated specimens of vanadium alloys are conducted using the miniature SS-3 specimen which is not ASTM approved. Detailed elastic-plastic finite element analysis of the specimen was conducted to show that, as long as the ultimate to yield strength ratio is less than or equal to 1.25 (which is satisfied by many irradiated materials), the stress-plastic strain curve obtained by using such a specimen is representative of the true material behavior.
Advanced Elastic/Inelastic Nuclear Data Development Project
Harmon, Frank; Chowdhury, Partha; Greife, Uwe; Fisher Hicks, Sally; Tsvetkov, Pavel; Rahn Vanhoy, Jeffrey; Hill, Tony; Kawano, Toshihiko; Slaughter, David
2015-06-08
The optical model is used to analyze the elastic and inelastic scattering of nucleons, deuterons, hellions, tritons, and alpha particles by the nuclei. Since this paper covers primarily neutron-nucleus scattering, the focus will be limited to only that interaction. For the sake of this model, the nucleus is described as a blob of nuclear matter with properties based upon its number of nucleons. This infers that a single potential can describe the interaction of particles with different energies with different nuclei.
Neutral Current Elastic Interactions in MiniBooNE
Dharmapalan, Ranjan; /Alabama U.
2011-10-01
Neutral Current Elastic (NCE) interactions in MiniBooNE are discussed. In the neutrino mode MiniBooNE reported: the flux averaged NCE differential cross section as a function of four-momentum transferred squared, an axial mass (M{sub A}) measurement, and a measurement of the strange quark spin content of the nucleon, {Delta}s. In the antineutrino mode we present the background-subtracted data which is compared with the Monte Carlo predictions.
Decay of helical Kelvin waves on a quantum vortex filament
Van Gorder, Robert A.
2014-07-15
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
Marsh, S.P.
1988-03-08
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.
1987-03-12
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.
Marsh, Stanley P. (Los Alamos, NM)
1988-01-01
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.
Wouters, L.F.
1958-10-28
The detection of the shape and amplitude of a radiation wave is discussed, particularly an apparatus for automatically indicating at spaced lntervals of time the radiation intensity at a flxed point as a measure of a radiation wave passing the point. The apparatus utilizes a number of photomultiplier tubes surrounding a scintillation type detector, For obtainlng time spaced signals proportional to radiation at predetermined intervals the photolnultiplier tubes are actuated ln sequence following detector incidence of a predetermined radiation level by electronic means. The time spaced signals so produced are then separately amplified and relayed to recording means.
Quantum positron acoustic waves
Metref, Hassina; Tribeche, Mouloud
2014-12-15
Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Hao, Shijie; Cui, Lishan; Wang, Hua; Jiang, Daqiang; Liu, Yinong; Yan, Jiaqiang; Ren, Yang; Han, Xiaodong; Brown, Dennis E.; Li, Ju
2016-02-10
Crystals held at ultrahigh elastic strains and stresses may exhibit exceptional physical and chemical properties. Individual metallic nanowires can sustain ultra-large elastic strains of 4-7%. However, retaining elastic strains of such magnitude in kilogram-scale nanowires is challenging. Here, we find that under active load, ~5.6% elastic strain can be achieved in Nb nanowires in a composite material. Moreover, large tensile (2.8%) and compressive (-2.4%) elastic strains can be retained in kilogram-scale Nb nanowires when the composite is unloaded to a free-standing condition. It is then demonstrated that the retained tensile elastic strains of Nb nanowires significantly increase their superconducting transitionmore » temperature and critical magnetic fields, corroborating ab initio calculations based on BCS theory. This free-standing nanocomposite design paradigm opens new avenues for retaining ultra-large elastic strains in great quantities of nanowires and elastic-strain-engineering at industrial scale.« less
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.
2015-01-08
We report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (dσ_{ν-barN→ν-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.
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.; et al
2015-01-08
We report the measurement of the flux-averaged antineutrino neutral current elastic scattering cross section (dσν-barN→ν-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.
Energy current imaging method for time reversal in elastic media
Anderson, Brian E; Ulrich, Timothy J; Le Bas, Pierre - Yves A; Larmat, Carene; Johnson, Paul A; Guyer, Robert A; Griffa, Michele
2009-01-01
An energy current imaging method is presented for use in locating sources of wave energy during the back propagation stage of the time reversal process. During the back propagation phase of an ideal time reversal experiment, wave energy coalesces from all angles of incidence to recreate the source event; after the recreation, wave energy diverges in every direction. An energy current imaging method based on this convergence/divergence behavior has been developed. The energy current imaging method yields a smaller spatial distribution for source reconstruction than is possible with traditional energy imaging methods.
Recent results in the study of heavy-ion elastic scattering at large angles. [180/sup 0/
Barrette, J.; Kahana, S.
1983-01-01
The observation, a few years ago, of unexpected large cross sections at backward angles in the elastic scattering of mass-asymmetric heavy ion systems gave us hope that we could learn something new and more precise on the properties of the average ion-ion potential. The subsequent observation of broad regular structures in the elastic and inelastic excitation functions near theta/sub cm/ = 180/sup 0/ were also very promising. Numerous models were proposed to explain some or all the observed features. These models can be divided mainly in two groups. Some try to modify directly the average optical potential whereas others associate the observed cross sections to a modification of specific partial waves outside the scope of the optical potential. This separation in two groups is not always clear since as demonstrated adding a Regge pole to a strongly absorbing potential is under some conditions perfectly equivalent to changing the shape of this potential. Similarly the resonances added to an S matrix can be understood as the manifestation of the potential resonances of a completely different optical potential. We describe recent calculations which have been carried on to try to understand the behavior of the data near the barrier.
Ibraeva, E. T.; Zhusupov, M. A.; Imambekov, O.; Sagindykov, Sh. Sh.
2008-07-15
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.
Menikoff, Ralph
2012-04-03
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.
Haynes Wave Basin | Open Energy Information
Wave Basin Jump to: navigation, search Basic Specifications Facility Name Haynes Wave Basin Overseeing Organization Texas A&M (Haynes) Hydrodynamic Testing Facility Type Wave Basin...
Microfabricated bulk wave acoustic bandgap device (Patent) |...
Office of Scientific and Technical Information (OSTI)
Microfabricated bulk wave acoustic bandgap device Title: Microfabricated bulk wave acoustic bandgap device A microfabricated bulk wave acoustic bandgap device comprises a periodic ...
Wave Star Energy | Open Energy Information
Star Energy Jump to: navigation, search Name: Wave Star Energy Place: Denmark Zip: DK-2920 Product: Denmark-based private wave device developer. References: Wave Star Energy1...
Elgen Wave | Open Energy Information
Elgen Wave Jump to: navigation, search Name: Elgen Wave Region: United States Sector: Marine and Hydrokinetic Website: www.elgenwave.com This company is listed in the Marine and...
Lo, W.-C.; Sposito, G.; Majer, E.
2007-02-01
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.
Solar type III radio bursts modulated by homochromous Alfvn waves
Zhao, G. Q.; Chen, L.; Wu, D. J.
2013-12-10
Solar type III radio bursts and their production mechanisms have been intensively studied in both theory and observation and are believed to be the most important signatures of electron acceleration in active regions. Recently, Wu et al. proposed that the electron-cyclotron maser emission (ECME) driven by an energetic electron beam could be responsible for producing type III bursts and pointed out that turbulent Alfvn waves can greatly influence the basic process of ECME via the oscillation of these electrons in the wave fields. This paper investigates effects of homochromous Alfvn waves (HAWs) on ECME driven by electron beams. Our results show that the growth rate of the O-mode wave will be significantly modulated by HAWs. We also discuss possible application to the formation of fine structures in type III bursts, such as so-called solar type IIIb radio bursts.
Property:Maximum Wave Height(m) at Wave Period(s) | Open Energy...
at Wave Period(s) Jump to: navigation, search Property Name Maximum Wave Height(m) at Wave Period(s) Property Type String Pages using the property "Maximum Wave Height(m) at Wave...
Phase stability and elastic properties of Cr-V alloys
Gao, M. C.; Suzuki, Y.; Schweiger, H.; Do?an, .N.; Hawk, J.; Widom M.
2013-02-20
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 CrV 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 Poissons 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 Poissons ratio for bcc CrV 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.
Erba, A. Dovesi, R.; Maul, J.; De La Pierre, M.
2015-05-28
We report accurate ab initio theoretical predictions of the elastic, seismic, and structural anisotropy of the orthorhombic Mg{sub 2}SiO{sub 4} forsterite crystal at high pressures (up to 20 GPa) and temperatures (up to its melting point, 2163 K), which constitute earth’s upper mantle conditions. Single-crystal elastic stiffness constants are evaluated up to 20 GPa and their first- and second-order pressure derivatives reported. Christoffel’s equation is solved at several pressures: directional seismic wave velocities and related properties (azimuthal and polarization seismic anisotropies) discussed. Thermal structural and average elastic properties, as computed within the quasi-harmonic approximation of the lattice potential, are predicted at high pressures and temperatures: directional thermal expansion coefficients, first- and second-order pressure derivatives of the isothermal bulk modulus, and P-V-T equation-of-state. The effect on computed properties of five different functionals, belonging to three different classes of approximations, of the density functional theory is explicitly investigated.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Fisher Research Group Layered Chalcogenides 29 February 2008 Controlling the Wave by Brad Plummer, SLAC Communications Stanford University researchers working in part at SSRL have discovered a novel set of properties pertaining to a compound of materials called tritellurides. These compounds, composed of three atoms of tellurium and a single atom of one of the rare earth elements, demonstrate unique electronic properties that can be controlled by altering the temperature of the material. The
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
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Evidence for residual elastic strain in deformed natural quartz
Kunz, Martin; Chen, Kai; Tamura,Nobumichi; Wenk, Hans-Rudolf
2009-01-30
Residual elastic strain in naturally deformed, quartz-containing rocks can be measured quantitatively in a petrographic thin section with high spatial resolution using Laue microdiffraction with white synchrotron x-rays. The measurements with a resolution of one micrometer allow the quantitative determination of the deviatoric strain tensor as a function of position within the crystal investigated. The observed equivalent strain values of 800-1200 microstrains represent a lower bound of the actual preserved residual strain in the rock, since the stress component perpendicular to the cut sample surface plane is released. The measured equivalent strain translates into an equivalent stress in the order of {approx} 50 MPa.
Green's function evaluation for three-dimensional exponentially graded elasticity
Criado Portero, Rafael M; Gray, Leonard J; Mantic, Vladislav; Paris, Federico
2008-01-01
The numerical implementation of the Green's function for an isotropic exponentially graded three dimensional elastic solid is reported. The formulas for the nonsingular {\\lq}grading term{\\rq} in this Green's function, originally deduced by Martin et al., \\emph{Proc. R. Soc. Lond. A, 458, 1931-1947, 2000}, are quite complicated, and a small error in one of the formulas is corrected. The evaluation of the fundamental solution is tested by employing indirect boundary integral formulation using a Galerkin approximation to solve several problems having analytic solutions. The numerical results indicate that the Green's function formulas, and their evaluation, are correct.
A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties
Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; Andr, M.; Jordanova, V. K.
2015-07-23
Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (20012010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.
A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties
Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.
2015-07-23
Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.
A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.
2015-07-23
Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of datamore » from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.« less
Ocean current wave interaction study
Hayes, J.G.
1980-09-20
A numerical model has been developed to incorporate refraction of ocean surface gravity waves by major ocean currents. The model is initialized with directional wave spectra and verified with aircraft synthetic aperture radar X band spectra, laser profilometer spectra, and pitch and roll buoy data. Data collected during the Marineland test experiment are used as surface truth observations for the wave-current study. Evidence of Gulf Stream refraction and trapping of surface waves as well as caustics in the current is shown and modeled assuming a nonuniform Gulf Stream distribution. Frequency and directional resolution of the wave spectral distribution and the current refraction patterns illustrates the need for further study of ocean current-wave interaction in wave refraction studies.
Pan Xiaoyin; Slamet, Marlina; Sahni, Viraht
2010-04-15
We extend our prior work on the construction of variational wave functions {psi} that are functionals of functions {chi}:{psi}={psi}[{chi}] rather than simply being functions. In this manner, the space of variations is expanded over those of traditional variational wave functions. In this article we perform the constrained search over the functions {chi} chosen such that the functional {psi}[{chi}] satisfies simultaneously the constraints of normalization and the exact expectation value of an arbitrary single- or two-particle Hermitian operator, while also leading to a rigorous upper bound to the energy. As such the wave function functional is accurate not only in the region of space in which the principal contributions to the energy arise but also in the other region of the space represented by the Hermitian operator. To demonstrate the efficacy of these ideas, we apply such a constrained search to the ground state of the negative ion of atomic hydrogen H{sup -}, the helium atom He, and its positive ions Li{sup +} and Be{sup 2+}. The operators W whose expectations are obtained exactly are the sum of the single-particle operators W={Sigma}{sub i}r{sub i}{sup n},n=-2,-1,1,2, W={Sigma}{sub i{delta}}(r{sub i}), W=-(1/2){Sigma}{sub i{nabla}i}{sup 2}, and the two-particle operators W={Sigma}{sub n}u{sup n},n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|. Comparisons with the method of Lagrangian multipliers and of other constructions of wave-function functionals are made. Finally, we present further insights into the construction of wave-function functionals by studying a previously proposed construction of functionals {psi}[{chi}] that lead to the exact expectation of arbitrary Hermitian operators. We discover that analogous to the solutions of the Schroedinger equation, there exist {psi}[{chi}] that are unphysical in that they lead to singular values for the expectations. We also explain the origin of the singularity.
Numerical simulation of fracture rocks and wave propagation by means of fractal theory
Valle G., R. del
1994-12-31
A numerical approach was developed for the dynamic simulation of fracture rocks and wave propagation. Based on some ideas of percolation theory and fractal growth, a network of particles and strings represent the rock model. To simulate an inhomogeneous medium, the particles and springs have random distributed elastic parameters and are implemented in the dynamic Navier equation. Some of the springs snap with criteria based on the confined stress applied, therefore creating a fractured rock consistent with the physical environment. The basic purpose of this research was to provide a method to construct a fractured rock with confined stress conditions as well as the wave propagation imposed in the model. Such models provide a better understanding of the behavior of wave propagation in fractured media. The synthetic seismic data obtained henceforth, can be used as a tool to develop methods for characterizing fractured rocks by means of geophysical inference.
Traveling waves for the mass in mass model of granular chains
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Kevrekidis, Panayotis G.; Stefanov, Atanas G.; Xu, Haitao
2016-08-01
In this work, we consider the mass in mass (or mass with mass) system of granular chains, namely, a granular chain involving additionally an internal (or, respectively, external) resonator. For these chains, we rigorously establish that under suitable “anti-resonance” conditions connecting the mass of the resonator and the speed of the wave, bell-shaped traveling-wave solutions continue to exist in the system, in a way reminiscent of the results proven for the standard granular chain of elastic Hertzian contacts. Finally, we also numerically touch upon settings, where the conditions do not hold, illustrating, in line also with recent experimental work, thatmore » non-monotonic waves bearing non-vanishing tails may exist in the latter case.« less
Antiproton-nucleus elastic and inelastic scattering at intermediate energies
Zhang, Y.; Liu, J.; Robson, B.A.; Li, Y. ||
1996-07-01
Using the experimental {bar {ital p}}{ital N} amplitude and multiple scattering theory, we obtained the antiproton optical potential at incident energies from 180 to 1800 MeV with the impulse approximation. It is found that the imaginary parts of the optical potential strengths are nearly constant between 130 and 140 MeV. The elastic data of the 180 MeV antiproton on {sup 12}C, {sup 16}O, {sup 40}Ca, and {sup 208}Pb and the inelastic data of the 180 MeV antiproton on {sup 12}C are analyzed within the framework of the eikonal approximation. The collective excitations to one-phonon levels are treated using the antiproton optical potential with the adiabatic approximation. The differential cross section of elastic scattering of 180 to 1833 MeV antiproton on {sup 12}C, on {sup 16}O, {sup 40}Ca, and {sup 208}Pb and the inelastic scattering of 180 to 1833 MeV antiproton {sup 12}C are predicted. {copyright} {ital 1996 The American Physical Society.}
Alaoui-Ismaili, N.; Guy, P.; Chassignole, B.
2014-02-18
The aim of this work is to measure the complex elastic tensor and Euler angles in very complex anisotropic media like austenitic steel welds, by inverse problem resolution from experimental data. The obtained experimental characteristics of the anisotropic material will be injected in a FE code developed by EDF enabling the simulation of an actual ultrasonic NDE of welds. The present work aims to provide reliable input data to the 3D future development of the code. In particular, this complex elastic tensor will allow to predict by modeling beam skewing ant attenuation in an austenitic weld. The investigation of such anisotropic media is very complex because of the directional dependency of the elastic stiffness tensor. Then we will discuss the use of a hybrid genetic algorithm to overcome this difficulty. The identification method is based on waveforms spectra reconstruction associated to a physical model describing wave propagation in plates, during underwater measurements. The entire procedure is qualified and validated using simulated data. Moreover, a comparison of the estimated elastic coefficients with literature values and ultrasonic measurements obtained in transmission is also given, at the end of the paper.
Bolted flange assembly: Preliminary elastic interaction data and improved bolt-up procedures
Bibel, G.; Ezell, R.
1996-01-01
Design bolt loading in a bolted flange connection is difficult to obtain because of elastic interaction. Elastic interaction data is presented for two different pipe flanges, three different gasket styles and two different bolting patterns. An algorithm that compensates for elastic interaction is given. Uniform bolt preload ({+-}2%) is obtained in a single pass bolt-up operation. The algorithm is based on experimentally obtained interaction coefficients.
WAVE DELAYING STRUCTURE FOR RECTANGULAR WAVE-GUIDES
Robertson-Shersby-Harvie, R.B.; Dain, J.
1956-11-13
This patent relates to wave-guides and in particular describes wave delaying structure located within a wave-guide. The disclosed wave-guide has an elongated fiat metal sheet arranged in a central plane of the guide and formed with a series of transverse inductive slots such that each face presents an inductive impedance to the guide. The sheet is thickened in the area between slots to increase the self capacity of the slots. Experimental results indicate that in a wave-guide loaded in accordance with the invention the guided wavelength changes more slowly as the air wavelength is changed than the guided wavelength does in wave-guides loaded by means of corrugations.
Elastic Moduli of Cemented Sphere Packs (Journal Article) | SciTech...
Office of Scientific and Technical Information (OSTI)
Journal Article: Elastic Moduli of Cemented Sphere Packs Citation Details In-Document ... Publication Date: 1999-07-01 OSTI Identifier: 850264 Resource Type: Journal Article ...
An Elastic Plastic Contact Model with Strain Hardening for the LAMMPS Granular Package
Kuhr, Bryan; Brake, Matthew Robert; Lechman, Jeremy B.
2015-03-01
The following details the implementation of an analytical elastic plastic contact model with strain hardening for normal im pacts into the LAMMPS granular package. The model assumes that, upon impact, the co llision has a period of elastic loading followed by a period of mixed elastic plas tic loading, with contributions to each mechanism estimated by a hyperbolic seca nt weight function. This function is implemented in the LAMMPS source code as the pair style gran/ep/history. Preliminary tests, simulating the pouring of pure nickel spheres, showed the elastic/plastic model took 1.66x as long as similar runs using gran/hertz/history.
Mechanical and Elastic Property Evaluation of n- and p-type Skutterudi...
Broader source: Energy.gov (indexed) [DOE]
This talk discusses the mechanical and elastic properties of skutterudites and the steps used to obtain them - discussing results in terms of module design and durability under ...
Energy Science and Technology Software Center (OSTI)
2015-02-16
The four-dimensional scattering function S(Q,w) obtained by inelastic neutron scattering measurements provides unique "dynamical fingerprints" of the spin state and interactions present in complex magnetic materials. Extracting this information however is currently a slow and complex process that may take an expert -depending on the complexity of the system- up to several weeks of painstaking work to complete. Spin Wave Genie was created to abstract and automate this process. It strives to both reduce themore » time to complete this analysis and make these calculations more accessible to a broader group of scientists and engineers.« less
Lipscombe, O. J.; Chen, G. F.; Fang, Chen; Perring, T. G.; Abernathy, Douglas L; Christianson, Andrew D; Egami, Takeshi; Wang, Nanlin; Hu, Jiangping; Dai, Pengcheng
2011-01-01
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.
Wave Energy Converter Effects on Nearshore Wave Propagation
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Energy Converter Effects on Nearshore Wave Propagation Jesse Roberts 1 , Grace Chang *2 , Craig Jones *3 Sandia National Laboratories 1515 Eubank SE, Albuquerque, NM 87123 USA 1...
Conversion of borehole Stoneley waves to channel waves in coal
Johnson, P.A.; Albright, J.N.
1987-01-01
Evidence for the mode conversion of borehole Stoneley waves to stratigraphically guided channel waves was discovered in data from a crosswell acoustic experiment conducted between wells penetrating thin coal strata located near Rifle, Colorado. Traveltime moveout observations show that borehole Stoneley waves, excited by a transmitter positioned at substantial distances in one well above and below a coal stratum at 2025 m depth, underwent partial conversion to a channel wave propagating away from the well through the coal. In an adjacent well the channel wave was detected at receiver locations within the coal, and borehole Stoneley waves, arising from a second partial conversion of channel waves, were detected at locations above and below the coal. The observed channel wave is inferred to be the third-higher Rayleigh mode based on comparison of the measured group velocity with theoretically derived dispersion curves. The identification of the mode conversion between borehole and stratigraphically guided waves is significant because coal penetrated by multiple wells may be detected without placing an acoustic transmitter or receiver within the waveguide. 13 refs., 6 figs., 1 tab.
Relevance of complex branch points for partial wave analysis
Ceci, S.; Svarc, A.; Doering, M.; Hanhart, C.; Krewald, S.; Meissner, U.-G.
2011-07-15
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.
Optical Gaussian beam interaction with one-dimensional thermal wave in the Raman-Nath configuration
Bukowski, Roman J
2009-03-01
Optical Gaussian beam interaction with a one-dimensional temperature field in the form of a thermal wave in the Raman-Nath configuration is analyzed. For the description of the Gaussian beam propagation through the nonstationary temperature field the complex geometric optics method was used. The influence of the refractive coefficient modulation by thermal wave on the complex ray phase, path, and amplitude was taken into account. It was assumed that for detection of the modulated Gaussian beam parameters two types of detector can be used: quadrant photodiodes or centroidal photodiodes. The influence of such parameters as the size and position of the Gaussian beam waist, the laser-screen (detector) distance, the thermal wave beam position and width, as well as thermal wave frequency and the distance between the probing optical beam axis and source of thermal waves on the so-called normal signal was taken into account.
Wave energy and intertidal productivity
Leigh, E.G. Jr.; Paine, R.T.; Quinn, J.F.; Suchanek, T.H.
1987-03-01
In the northern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 x 10/sup 8/ J, per m/sup 2/ in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms harness wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organism, and protect intertidal residents by knocking away their enemies or preventing them from feeding.
Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...
Wave Basin | Open Energy Information
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Guided acoustic wave inspection system
Chinn, Diane J.
2004-10-05
A system for inspecting a conduit for undesirable characteristics. A transducer system induces guided acoustic waves onto said conduit. The transducer system detects the undesirable characteristics of the conduit by receiving guided acoustic waves that contain information about the undesirable characteristics. The conduit has at least two sides and the transducer system utilizes flexural modes of propagation to provide inspection using access from only the one side of the conduit. Cracking is detected with pulse-echo testing using one transducer to both send and receive the guided acoustic waves. Thinning is detected in through-transmission testing where one transducer sends and another transducer receives the guided acoustic waves.
Harnessing Energy from Ocean Waves
Lehmann, Marcus
2015-05-06
Berkeley Lab scientist Marcus Lehmann, a member of the Lab's Cyclotron Road cohort, discusses his research on harnessing energy from ocean waves.
Elastic properties of protein functionalized nanoporous polymer films
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Charles T. Black; Wang, Haoyu; Akcora, Pinar
2015-12-16
Retaining the conformational structure and bioactivity of immobilized proteins is important for biosensor designs and drug delivery systems. Confined environments often lead to changes in conformation and functions of proteins. In this study, lysozyme is chemically tethered into nanopores of polystyrene thin films, and submicron pores in poly(methyl methacrylate) films are functionalized with streptavidin. Nanoindentation experiments show that stiffness of streptavidin increases with decreasing submicron pore sizes. Lysozymes in polystyrene nanopores are found to behave stiffer than the submicron pore sizes and still retain their specific bioactivity relative to the proteins on flat surfaces. Lastly, our results show that proteinmore » functionalized ordered nanoporous polystyrene/poly(methyl methacrylate) films present heterogeneous elasticity and can be used to study interactions between free proteins and designed surfaces.« less
Elastic properties of protein functionalized nanoporous polymer films
Charles T. Black; Wang, Haoyu; Akcora, Pinar
2015-12-16
Retaining the conformational structure and bioactivity of immobilized proteins is important for biosensor designs and drug delivery systems. Confined environments often lead to changes in conformation and functions of proteins. In this study, lysozyme is chemically tethered into nanopores of polystyrene thin films, and submicron pores in poly(methyl methacrylate) films are functionalized with streptavidin. Nanoindentation experiments show that stiffness of streptavidin increases with decreasing submicron pore sizes. Lysozymes in polystyrene nanopores are found to behave stiffer than the submicron pore sizes and still retain their specific bioactivity relative to the proteins on flat surfaces. Lastly, our results show that protein functionalized ordered nanoporous polystyrene/poly(methyl methacrylate) films present heterogeneous elasticity and can be used to study interactions between free proteins and designed surfaces.
Elastic Electron Scattering from Tritium and Helium-3
DOE R&D Accomplishments [OSTI]
Collard, H.; Hofstadter, R.; Hughes, E. B.; Johansson, A.; Yearian, M. R.; Day, R. B.; Wagner, R. T.
1964-10-01
The mirror nuclei of tritium and helium-3 have been studied by the method of elastic electron scattering. Absolute cross sections have been measured for incident electron energies in the range 110 - 690 MeV at scattering angles lying between 40 degrees and 135 degrees in this energy range. The data have been interpreted in a straightforward manner and form factors are given for the distributions of charge and magnetic moment in the two nuclei over a range of four-momentum transfer squared 1.0 - 8.0 F{sup -2}. Model-independent radii of the charge and magnetic moment distributions are given and an attempt is made to deduce form factors describing the spatial distribution of the protons in tritium and helium-3.
A Double Scattering Analytical Model For Elastic Recoil Detection Analysis
Barradas, N. P.; Lorenz, K.; Alves, E.; Darakchieva, V.
2011-06-01
We present an analytical model for calculation of double scattering in elastic recoil detection measurements. Only events involving the beam particle and the recoil are considered, i.e. 1) an ion scatters off a target element and then produces a recoil, and 2) an ion produces a recoil which then scatters off a target element. Events involving intermediate recoils are not considered, i.e. when the primary ion produces a recoil which then produces a second recoil. If the recoil element is also present in the stopping foil, recoil events in the stopping foil are also calculated. We included the model in the standard code for IBA data analysis NDF, and applied it to the measurement of hydrogen in Si.
NN inversion potentials intermediate energy proton-nucleus elastic scattering
Arellano, H.F.; Brieva, F.A.; Love, W.G.; Geramb, H.V. von
1995-10-01
Recently developed nucleon-nucleon interactions using the quantum inverse scattering method shed new fight on the off-shell properties of the internucleon effective force for nucleon-nucleus scattering. Calculations of proton elastic scattering from {sup 40}Ca and {sup 208}Pb in the 500 MeV region show that variations in off-shell contributions are determined to a great extent by the accuracy with which the nucleon-nucleon phase shifts are reproduced. The study is based on the full-folding approach to the nucleon-nucleus optical potential which allows a deep understanding of the interplay between on- and off-shell effects in nucleon scattering. Results and the promising extension offered by the inversion potentials beyond the range of validity of the low-energy internucleon forces will be discussed.
Yang, Jinwen; Gao, Tao; Liu, Benqiong; Sun, Guangai; Chen, Bo
2015-03-28
Structural, elastic anisotropy, dynamical, and thermodynamic properties of U{sub 2}Ti have been studied by employing density functional theory and density functional perturbative theory. The optimized lattice parameters a, c, unit volume V, bulk modulus B, and bond lengths d{sub U-U}, d{sub U-Ti} of U{sub 2}Ti are in favorable agreement with the available experimental data and other theoretical values. The elastic constants under pressure were obtained using “energy-strain” method. The polycrystalline modulus, Poisson's ratio, brittle/ductile characteristics, Debye temperature and the integration of elastic wave velocities over different directions, and hardness under pressure are also evaluated successfully. The anisotropy of the directional bulk modulus and the Young's modulus is systematically predicted for the first time. It turns out that U{sub 2}Ti should be stabilized mechanically up to 100 GPa, this compound just possesses slightly elastic anisotropy at zero pressure; however, the anisotropy becomes more and more significant with the increasing pressure. In particular, the phonon dispersion curves and phonon density of state under pressure are reported for the first time. The Raman and infrared-active phonon modes at Γ point are further assigned. Our results indicate that U{sub 2}Ti is also stable dynamically up to 100 GPa. Additionally, within the calculated phonon density of states, the thermodynamic properties are predicted.
Topological horseshoes in travelling waves of discretized nonlinear wave equations
Chen, Yi-Chiuan; Chen, Shyan-Shiou; Yuan, Juan-Ming
2014-04-15
Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.