The elastic strain energy of crystallographic shear planes in reduced tungsten trioxide
International Nuclear Information System (INIS)
Iguchi, E.; Tilley, R.J.D.
1977-01-01
Calculations of the elastic strain energy due to crystallographic shear (c.s.) planes lying upon 102, 103 and 001 planes in reduced tungsten trioxide crystals have been made. The cases analysed in detail are for both isolated c.s. planes and for pairs of c.s. planes. These results are used to determine the elastic strain energy per unit volume for crystals containing ordered arrays of c.s. planes. It was found that the magnitude of the elastic strain energy was in the sequence 001 < 102 < 103 and that at relatively small inter-c.s. spacings the curves of elastic strain energy against c.s. plane separation take the form of a series of peaks and valleys. These results are compared with experimental observations of c.s. plane spacings in substantially reduced crystals containing quasi-ordered arrays of c.s. planes and with observations of c.s. plane nucleation and growth in both slightly and more appreciably reduced crystals. It was found that the elastic strain energy plays a significant part in controlling the microstructure of c.s. plane arrays in such cases. (author)
Zhou, Yarong; Yang, Xu; Pan, Dongmei; Wang, Binglei
2018-04-01
Flexoelectricity, the coupling of strain gradient and polarization, exists in all the dielectric materials and numerous models have been proposed to study this mechanism. However, the contribution of strain gradient elasticity has typically been underestimated. In this work, inspired by the one-length scale parameter model developed by Deng et al. [19], we incorporate three length-scale parameters to carefully capture the contribution of the purely mechanical strain gradients on flexoelectricity. This three-parameter model is more flexible and could be applied to investigate the flexoelectricity in a wide range of complicated deformations. Accordingly, we carry out our analysis by studying a dielectric nanobeam under different boundary conditions. We show that the strain gradient elasticity and flexoelectricity have apparent size effects and significant influence on the electromechanical response. In particular, the strain gradient effects could significantly reduce the energy efficiency, indicating their importance and necessity. This work may be helpful in understanding the mechanism of flexoelectricity at the nanoscale and sheds light on the flexoelectricity energy harvesting.
The role of chemical free energy and elastic strain in the nucleation of zirconium hydride
International Nuclear Information System (INIS)
Barrow, A.T.W.; Toffolon-Masclet, C.; Almer, J.; Daymond, M.R.
2013-01-01
In this work a combination of synchrotron X-ray diffraction and thermodynamic modelling has been used to study the dissolution and precipitation of zirconium hydride in α-Zr establishing the role of elastic misfit strain and chemical free energy in the α → α + δ phase transformation. The nucleation of zirconium hydride is dominated by the chemical free energy where the chemical driving force for hydride precipitation is proportional to the terminal-solid solubility for precipitation and can be predicted by a function that is analogous to the universal nucleation parameter for the bainite transformation in ferrous alloys. The terminal-solid solubility for precipitation was found to be kinetically limited ⩾287 °C at a cooling rate of 5 °C min −1 or greater. The terminal solubilities were established using an offset method applied to the lattice strain data where a resolution of ∼10 wppm H can be achieved in the 〈c〉-direction. This is aided by the introduction of intra-granular strains in the 〈c〉-direction during cooling as a result of the thermal expansion anisotropy which increases the anisotropy associated with the misfitting H atoms within the α-Zr lattice
Spectral Modeling of Residual Stress and Stored Elastic Strain Energy in Thermal Barrier Coatings
Energy Technology Data Exchange (ETDEWEB)
Donegan, Sean; Rolett, Anthony
2013-12-31
Solutions to the thermoelastic problem are important for characterizing the response under temperature change of refractory systems. This work extends a spectral fast Fourier transform (FFT) technique to analyze the thermoelastic behavior of thermal barrier coatings (TBCs), with the intent of probing the local origins of failure in TBCs. The thermoelastic FFT (teFFT) approach allows for the characterization of local thermal residual stress and strain fields, which constitute the origins of failure in TBC systems. A technique based on statistical extreme value theory known as peaks-over-threshold (POT) is developed to quantify the extreme values ("hot spots") of stored elastic strain energy (i.e., elastic energy density, or EED). The resolution dependence of the teFFT method is assessed through a sensitivity study of the extreme values in EED. The sensitivity study is performed both for the local (point-by-point) eld distributions as well as the grain scale eld distributions. A convergence behavior to a particular distribution shape is demonstrated for the local elds. The grain scale fields are shown to exhibit a possible convergence to a maximum level of EED. To apply the teFFT method to TBC systems, 3D synthetic microstructures are created to approximate actual TBC microstructures. The morphology of the grains in each constituent layer as well as the texture is controlled. A variety of TBC materials, including industry standard materials and potential future materials, are analyzed using the teFFT. The resulting hot spots are quantified using the POT approach. A correlation between hot spots in EED and interface rumpling between constituent layers is demonstrated, particularly for the interface between the bond coat (BC) and the thermally grown oxide (TGO) layer.
Strain fluctuations and elastic constants
Energy Technology Data Exchange (ETDEWEB)
Parrinello, M.; Rahman, A.
1982-03-01
It is shown that the elastic strain fluctuations are a direct measure of elastic compliances in a general anisotropic medium; depending on the ensemble in which the fluctuation is measured either the isothermal or the adiabatic compliances are obtained. These fluctuations can now be calculated in a constant enthalpy and pressure, and hence, constant entropy, ensemble due to recent develpments in the molecular dynamics techniques. A calculation for a Ni single crystal under uniform uniaxial 100 tensile or compressive load is presented as an illustration of the relationships derived between various strain fluctuations and the elastic modulii. The Born stability criteria and the behavior of strain fluctuations are shown to be related.
Terasaki, Hidenori; Moriguchi, Koji; Tomio, Yusaku; Yamagishi, Hideki; Morito, Shigekazu
2017-12-01
The effect of carbon content on the density of variant-pair boundaries was investigated in 9Ni steel using an electron backscatter diffraction patterns method. The changes in the density of variant-pair boundaries were correlated with the nondestructive measured values of shear modulus of the austenite phase at the phase transformation point. Furthermore, the effective grain size was correlated with the shear modulus and the density of variant-pair boundaries. These relations are discussed from the viewpoint of self-accommodation of elastic strain energy and the nucleation event in the bainite and martensitic transformations.
Elasticity of energy consumption
International Nuclear Information System (INIS)
Stam, M.
2004-01-01
Insight is given into the price elasticities of several energy carriers. Next, attention is paid to the impact of the discussion on changes of the Regulating Energy Levy (REB, abbreviated in Dutch) in the Netherlands [nl
Energy Technology Data Exchange (ETDEWEB)
Baram, J.; Avissar, J.; Gefen, Y.; Rosen, M.
1980-05-01
The objective of this paper is to present experimental evidence concerning the acoustic energy evolved during the heating and cooling phase changes in Au-47.5 at.% Cd polycrystals. The results are examined from the point of view of the stored elastic strain energy during the martensite formation, and the frictional work that is dissipated by the movement of martensite interfaces in either direction, upon heating and cooling.
Managheb, S. A. M.; Ziaei-Rad, S.; Tikani, R.
2018-05-01
The coupling between polarization and strain gradients is called flexoelectricity. This phenomenon exists in all dielectrics with any symmetry. In this paper, energy harvesting from a Timoshenko beam is studied by considering the flexoelectric and strain gradient effects. General governing equations and related boundary conditions are derived using Hamilton's principle. The flexoelectric effects are defined by gradients of normal and shear strains which lead to a more general model. The developed model also covers the classical Timoshenko beam theory by ignoring the flexoelectric effect. Based on the developed model, flexoelectricity effect on dielectric beams and energy harvesting from cantilever beam under harmonic base excitation is investigated. A parametric study was conducted to evaluate the effects of flexoelectric coefficients, strain gradient constants, base acceleration and the attaching tip mass on the energy harvested from a cantilever Timoshenko beam. Results show that the flexoelectricity has a significant effect on the energy harvester performance, especially in submicron and nano scales. In addition, this effect makes the beam to behave softer than before and also it changes the harvester first resonance frequency. The present study provides guidance for flexoelectric nano-beam analysis and a method to evaluate the performance of energy harvester in nano-dielectric devices.
Modeling elastic anisotropy in strained heteroepitaxy.
Dixit, Gopal Krishna; Ranganathan, Madhav
2017-09-20
Using a continuum evolution equation, we model the growth and evolution of quantum dots in the heteroepitaxial Ge on Si(0 0 1) system in a molecular beam epitaxy unit. We formulate our model in terms of evolution due to deposition, and due to surface diffusion which is governed by a free energy. This free energy has contributions from surface energy, curvature, wetting effects and elastic energy due to lattice mismatch between the film and the substrate. In addition to anisotropy due to surface energy which favors facet formation, we also incorporate elastic anisotropy due to an underlying crystal lattice. The complicated elastic problem of the film-substrate system subjected to boundary conditions at the free surface, interface and the bulk substrate is solved by perturbation analysis using a small slope approximation. This permits an analysis of effects at different orders in the slope and sheds new light on the observed behavior. Linear stability analysis shows the early evolution of the instability towards dot formation. The elastic anisotropy causes a change in the alignment of dots in the linear regime, whereas the surface energy anisotropy changes the dot shapes at the nonlinear regime. Numerical simulation of the full nonlinear equations shows the evolution of the surface morphology. In particular, we show, for parameters of the [Formula: see text] [Formula: see text] on Si(0 0 1), the surface energy anisotropy dominates the shapes of the quantum dots, whereas their alignment is influenced by the elastic energy anisotropy. The anisotropy in elasticity causes a further elongation of the islands whose coarsening is interrupted due to [Formula: see text] facets on the surface.
Modeling elastic anisotropy in strained heteroepitaxy
Krishna Dixit, Gopal; Ranganathan, Madhav
2017-09-01
Using a continuum evolution equation, we model the growth and evolution of quantum dots in the heteroepitaxial Ge on Si(0 0 1) system in a molecular beam epitaxy unit. We formulate our model in terms of evolution due to deposition, and due to surface diffusion which is governed by a free energy. This free energy has contributions from surface energy, curvature, wetting effects and elastic energy due to lattice mismatch between the film and the substrate. In addition to anisotropy due to surface energy which favors facet formation, we also incorporate elastic anisotropy due to an underlying crystal lattice. The complicated elastic problem of the film-substrate system subjected to boundary conditions at the free surface, interface and the bulk substrate is solved by perturbation analysis using a small slope approximation. This permits an analysis of effects at different orders in the slope and sheds new light on the observed behavior. Linear stability analysis shows the early evolution of the instability towards dot formation. The elastic anisotropy causes a change in the alignment of dots in the linear regime, whereas the surface energy anisotropy changes the dot shapes at the nonlinear regime. Numerical simulation of the full nonlinear equations shows the evolution of the surface morphology. In particular, we show, for parameters of the Ge0.25 Si0.75 on Si(0 0 1), the surface energy anisotropy dominates the shapes of the quantum dots, whereas their alignment is influenced by the elastic energy anisotropy. The anisotropy in elasticity causes a further elongation of the islands whose coarsening is interrupted due to facets on the surface.
High energy elastic hadron scattering
International Nuclear Information System (INIS)
Fearnly, T.A.
1986-04-01
The paper deals with the WA7 experiment at the CERN super proton synchrotron (SPS). The elastic differential cross sections of pion-proton, kaon-proton, antiproton-proton, and proton-proton at lower SPS energies over a wide range of momentum transfer were measured. Some theoretical models in the light of the experimental results are reviewed, and a comprehensive impact parameter analysis of antiproton-proton elastic scattering over a wide energy range is presented. A nucleon valence core model for high energy proton-proton and antiproton-proton elastic scattering is described
Elastic interaction energies of defect structures
International Nuclear Information System (INIS)
Seitz, E.; de Fontaine, D.
1976-01-01
The elastic strain energy between point defects and small disk-shaped clusters of defects are calculated to determine stable configurations. A distortion tensor of tetragonal symmetry is assigned to each impurity atom. The tetragonality ratio t is varied to cover needle-type (t greater than 1), spherical (t = 1) and disk-type (t less than 0) strain fields. To vary the elastic properties of the host material, Fe, Cu, Al, and V were chosen as examples. Computer calculations are based on the microscopic theory of elasticity which emphasizes calculations in discrete Fourier space. Pairs of point defects order along [001] for t less than 1 and along (001) for t = 1 for all host elements. For t greater than 1 fcc lattices and bcc lattices behave differently. It is shown that only certain three dimensional periodic arrangements of parallel and perpendicular disk-like defect clusters are realized for given tetragonality ratio t and host element
Elastic constants from microscopic strain fluctuations
Sengupta; Nielaba; Rao; Binder
2000-02-01
Fluctuations of the instantaneous local Lagrangian strain epsilon(ij)(r,t), measured with respect to a static "reference" lattice, are used to obtain accurate estimates of the elastic constants of model solids from atomistic computer simulations. The measured strains are systematically coarse-grained by averaging them within subsystems (of size L(b)) of a system (of total size L) in the canonical ensemble. Using a simple finite size scaling theory we predict the behavior of the fluctuations as a function of L(b)/L and extract elastic constants of the system in the thermodynamic limit at nonzero temperature. Our method is simple to implement, efficient, and general enough to be able to handle a wide class of model systems, including those with singular potentials without any essential modification. We illustrate the technique by computing isothermal elastic constants of "hard" and "soft" disk triangular solids in two dimensions from Monte Carlo and molecular dynamics simulations. We compare our results with those from earlier simulations and theory.
Calculation of elastic-plastic strain ranges for fatigue analysis based on linear elastic stresses
International Nuclear Information System (INIS)
Sauer, G.
1998-01-01
Fatigue analysis requires that the maximum strain ranges be known. These strain ranges are generally computed from linear elastic analysis. The elastic strain ranges are enhanced by a factor K e to obtain the total elastic-plastic strain range. The reliability of the fatigue analysis depends on the quality of this factor. Formulae for calculating the K e factor are proposed. A beam is introduced as a computational model for determining the elastic-plastic strains. The beam is loaded by the elastic stresses of the real structure. The elastic-plastic strains of the beam are compared with the beam's elastic strains. This comparison furnishes explicit expressions for the K e factor. The K e factor is tested by means of seven examples. (orig.)
Strain gradient elasticity within the symmetric BEM formulation
Directory of Open Access Journals (Sweden)
S. Terravecchia,
2014-07-01
Full Text Available The symmetric Galerkin Boundary Element Method is used to address a class of strain gradient elastic materials featured by a free energy function of the (classical strain and of its (first gradient. With respect to the classical elasticity, additional response variables intervene, such as the normal derivative of the displacements on the boundary, and the work-coniugate double tractions. The fundamental solutions - featuring a fourth order partial differential equations (PDEs system - exhibit singularities which in 2D may be of the order 1/ r 4 . New techniques are developed, which allow the elimination of most of the latter singularities. The present paper has to be intended as a research communication wherein some results, being elaborated within a more general paper [1], are reported.
Tyumentsev, A. N.; Ditenberg, I. A.; Sukhanov, I. I.
2018-02-01
In the zones of strain localization in the region of elastic distortions and nanodipoles of partial disclinations representing the defects of elastically deformed medium, a theoretical analysis of the elastically stressed state and the energy of these defects, including the cases of their transformation into more complex ensembles of interrelated disclinations, is performed. Using the analytical results, the mechanisms of strain localization are discussed in the stages of nucleation and propagation of the bands of elastic and plastic strain localization formed in these zones (including the cases of nanocrystalline structure formation).
Strain-energy effects on dynamic fragmentation
International Nuclear Information System (INIS)
Glenn, L.A.; Chudnovsky, A.
1986-01-01
Grady's model of the dynamic fragmentation process, in which the average fragment size is determined by balancing the local kinetic energy and the surface energy, is modified to include the stored elastic (strain) energy. The revised model predicts that the strain energy should dominate for brittle materials, with low fracture toughness and high fracture-initiation stress. This conclusion is not borne out, however, by limited experimental data on brittle steels, even when the kinetic-energy density is small compared with the strain-energy density
Atomistic Calculation of Elastic Moduli in Strained Silicon
National Research Council Canada - National Science Library
Zhu, Richard; Pan, Ernian; Chung, Peter W; Cai, Xinli; Liew, Kim M; Buldum, Alper
2007-01-01
.... Using our approach, the bulk modulus, effective elastic stiffnesses C11, C12, and C44 of the strained silicon, including also the effective Young's modulus and Poisson's ratio, are all calculated...
Plane strain problem in microstretch elastic solid
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
College, Patti 143 416, India. 3Department of Mathematics, Guru Nanak Dev University, Amritsar 143 005, ... lem in microstretch elastic solid by employing the eigenvalue approach. 975. Page 2. 976. Rajneesh Kumar et al. 2. Basic equations ..... of the matrix A are characteristic roots of (29) assuming that real parts of qs.
Elastic energy release in great earthquakes and eruptions
Directory of Open Access Journals (Sweden)
Agust eGudmundsson
2014-05-01
Full Text Available The sizes of earthquakes are measured using well-defined, measurable quantities such as seismic moment and released (transformed elastic energy. No similar measures exist for the sizes of volcanic eruptions, making it difficult to compare the energies released in earthquakes and eruptions. Here I provide a new measure of the elastic energy (the potential mechanical energy associated with magma chamber rupture and contraction (shrinkage during an eruption. For earthquakes and eruptions, elastic energy derives from two sources: (1 the strain energy stored in the volcano/fault zone before rupture, and (2 the external applied load (force, pressure, stress, displacement on the volcano/fault zone. From thermodynamic considerations it follows that the elastic energy released or transformed (dU during an eruption is directly proportional to the excess pressure (pe in the magma chamber at the time of rupture multiplied by the volume decrease (-dVc of the chamber, so that . This formula can be used as a basis for a new eruption magnitude scale, based on elastic energy released, which can be related to the moment-magnitude scale for earthquakes. For very large eruptions (>100 km3, the volume of the feeder-dike is negligible, so that the decrease in chamber volume during an eruption corresponds roughly to the associated volume of erupted materials , so that the elastic energy is . Using a typical excess pressures of 5 MPa, it is shown that the largest known eruptions on Earth, such as the explosive La Garita Caldera eruption (27-28 million years ago and largest single (effusive Colombia River basalt lava flows (15-16 million years ago, both of which have estimated volumes of about 5000 km3, released elastic energy of the order of 10EJ. For comparison, the seismic moment of the largest earthquake ever recorded, the M9.5 1960 Chile earthquake, is estimated at 100 ZJ and the associated elastic energy release at 10EJ.
Burial stress and elastic strain of carbonate rocks
DEFF Research Database (Denmark)
Fabricius, Ida Lykke
2014-01-01
Burial stress on a sediment or sedimentary rock is relevant for predicting compaction or failure caused by changes in, e.g., pore pressure in the subsurface. For this purpose, the stress is conventionally expressed in terms of its effect: “the effective stress” defined as the consequent elastic...... strain multiplied by the rock frame modulus. We cannot measure the strain directly in the subsurface, but from the data on bulk density and P‐wave velocity, we can estimate the rock frame modulus and Biot's coefficient and then calculate the “effective vertical stress” as the total vertical stress minus...... the product of pore pressure and Biot's coefficient. We can now calculate the elastic strain by dividing “effective stress” with the rock frame modulus. By this procedure, the degree of elastic deformation at a given time and depth can be directly expressed. This facilitates the discussion of the deformation...
Atomistic modelling of diffusional phase transformations with elastic strain
International Nuclear Information System (INIS)
Mason, D R; Rudd, R E; Sutton, A P
2004-01-01
Phase transformations in 2xxx series aluminium alloys (Al-Cu-Mg) are investigated with an off-lattice atomistic kinetic Monte Carlo simulation incorporating the effects of strain around misfitting atoms and vacancies. Atomic interactions are modelled by Finnis-Sinclair potentials constructed for these simulations. Vacancy diffusion is modelled by comparing the energies of trial states, where the system is partially relaxed for each trial state. No special requirements are made about the description of atomic interactions, making our approach suitable for more fundamentally based models such as tight binding if sufficient computational resources are available. Only a limited precision is required for the energy of each trial state, determined by the value of k B T. Since the change in the relaxation displacement field caused by a vacancy hop decays as 1/r 3 , it is sufficient to determine the next move by relaxing only those atoms in a sphere of finite radius centred on the moving vacancy. However, once the next move has been selected, the entire system is relaxed. Simulations of the early stages of phase separation in Al-Cu with elastic relaxation show an enhanced rate of clustering compared to those performed on the same system with a rigid lattice
Pb nanoprecipitates in Al: Magic-shape effects due to elastic strain
DEFF Research Database (Denmark)
Hamilton, J.C.; Leoard, F.; Johnson, Erik
2007-01-01
We present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of "magic shapes," i.e., shapes having near-zero homogeneous elastic strains. Our quantitative atomistic calculations of edge energies show their effect on precipitate shape to be negligible, thus...
Cowgill, E.; Gold, R. D.; Arrowsmith, R.; Friedrich, A. M.
2015-12-01
In elastic rebound theory, hazard increases as interseismic strain rebuilds after rupture. This model is challenged by the temporal variation in the pacing of major earthquakes that is both predicted by mechanical models and suggested by some long paleoseismic records (e.g., 1-3). However, the extent of such behavior remains unclear due to a lack of long (5-25 ky) records of fault slip. Using Monte Carlo analysis of 11 offset landforms, we determined a 16-ky record of fault slip for the active, left-lateral Altyn Tagh fault, which bounds the NW margin of the Tibetan Plateau. This history reveals a pulse of accelerated slip between 6.4 and 6.0 ka, during which the fault slipped 9 +14/-2 m at a rate of 23 +35/-5 mm/y, or ~3x the 16 ky average of 8.1 +1.2/-0.9mm/y. These two modes of earthquake behavior suggest temporal variation in the rates of stress storage and release. The simplest explanation for the pulse is a cluster of 2-8 Mw > 7.5 earthquakes. Such supercyclicity has been reported for the Sunda (4) and Cascadia (3) megathrusts, but contrasts with steady slip along the strike-slip Alpine fault (5), for example. A second possibility is that the pulse reflects a single, unusually large rupture. However, this Black Swan event is unlikely: empirical scaling relationships require a Mw 8.2 rupture of the entire 1200-km-long ATF to produce 7 m of average slip. Likewise, Coulomb stress change from rupture on the adjacent North Altyn fault is of modest magnitude and overlap with the ATF. Poor temporal correlation between precipitation and the slip pulse argues against climatically modulated changes in surface loading (lakes/ice) or pore-fluid pressure. "Paleoslip" studies such as this sacrifice the single-event resolution of paleoseismology in exchange for long records that quantify both the timing and magnitude of fault slip averaged over multiple ruptures, and are essential for documenting temporal variations in fault slip as we begin to use calibrated physical
Population and energy elasticity of tornado casualties
Fricker, Tyler; Elsner, James B.; Jagger, Thomas H.
2017-04-01
Tornadoes are capable of catastrophic destruction and mass casualties, but there are yet no estimates of how sensitive the number of casualties are to changes in the number of people in harm's way or to changes in tornado energy. Here the relationship between tornado casualties (deaths and injuries), population, and energy dissipation is quantified using the economic concept of "elasticity." Records of casualties from individual tornadoes over the period 2007-2015 are fit to a regression model. The coefficient on the population term (population elasticity) indicates that a doubling in population increases the casualty rate by 21% [(17, 24)%, 95% credible interval]. The coefficient on the energy term (energy elasticity) indicates that a doubling in energy dissipation leads to a 33% [(30, 35)%, 95% credible interval] increase in the casualty rate. The difference in elasticity values show that on average, changes in energy dissipation have been relatively more important in explaining tornado casualties than changes in population. Assuming no changes in warning effectiveness or mitigation efforts, these elasticity estimates can be used to project changes in casualties given the known population trends and possible trends in tornado activity.
Elastic form factors at higher CEBAF energies
Energy Technology Data Exchange (ETDEWEB)
Petratos, G.G. [Kent State Univ., OH (United States)
1994-04-01
The prospects for elastic scattering from few body systems with higher beam energies at CEBAF is presented. The deuteron and{sup 3}He elastic structure functions A(Q{sup 2}) can be measured at sufficiently high momentum transfers to study the transition between the conventional meson-nucleon and the constituent quark-gluon descriptions. Possible improvements in the proton magnetic form factor data are also presented.
Elastic energies of coherent germanium islands on silicon
International Nuclear Information System (INIS)
Vanderbilt, D.; Wickham, L.K.
1991-01-01
Motivated by recent observations of coherent Ge island formation during growth of Ge on Si (100), the authors of this paper have carried out a theoretical study of the elastic energies associated with the evolution of a uniform strained overlayer as it segregates into coherent islands. In the context of a two-dimensional model, the authors have explored the conditions under which coherent islands may be energetically favored over both uniform epitaxial films and dislocated islands. The authors find that if the interface energy (for dislocated islands) is more than about 15% of the surface energy, then there is a range of island sizes for which the coherent island structure is preferred
International Nuclear Information System (INIS)
Kasahara, Naoto; Takasho, Hideki
1998-12-01
Elevated temperature structural design codes pay attention to strain concentration at structural discontinuities due to creep and plasticity, since it causes to enlarge creep-fatigue damage of material. One of the difficulties to predict strain concentration is its dependency on loading, constitutive equations, and relaxation time. This study investigated fundamental mechanism of strain concentration and its main factors. It was clarified that strain concentration was caused from strain redistribution between elastic and inelastic regions, which can be quantified by the elastic follow-up parameter. As a function of inelastic strain, the elastic follow-up parameter can describe variation of strain concentration during incremental loading and relaxation process, caused by transition of strain distribution from peak strain concentration to secondary stress redistribution. Structures have their own elastic follow-up characteristics as a function of inelastic strain, which is insensitive to constitutive equations. It means that application of inelastic analysis is not difficult to obtain elastic follow-up characteristics. (author)
pp elastic scattering at LHC energies
Energy Technology Data Exchange (ETDEWEB)
Kohara, A.K.; Ferreira, E.; Kodama, T. [Universidade Federal do Rio de Janeiro, Instituto de Fisica, C.P. 68528, Rio de Janeiro, RJ (Brazil)
2014-11-15
Using a unified analytic representation for the elastic scattering amplitudes of pp scattering valid for all energies above 20 GeV, the behavior of observables in the LHC collisions in the range √(s) = 2.76-14 TeV is discussed. After the precise description of dσ/dt at 7 TeV, we discuss the energy dependence of the amplitudes and expect that the proposed analytical forms give equally good predictions for the future experiments. (orig.)
pp elastic scattering at LHC energies
International Nuclear Information System (INIS)
Kohara, A.K.; Ferreira, E.; Kodama, T.
2014-01-01
Using a unified analytic representation for the elastic scattering amplitudes of pp scattering valid for all energies above 20 GeV, the behavior of observables in the LHC collisions in the range √(s) = 2.76-14 TeV is discussed. After the precise description of dσ/dt at 7 TeV, we discuss the energy dependence of the amplitudes and expect that the proposed analytical forms give equally good predictions for the future experiments. (orig.)
Clay behaviour under thermal gradients elastic and plastic strains
International Nuclear Information System (INIS)
Pintado, Xavier; Autio, Jorma; Punkkinen, Olli
2010-01-01
Document available in extended abstract form only. The nuclear waste repositories will generate strong temperature gradients at the clay barrier. The heat and water transport generate volume change in the clay. An experimental work is proposed here. The clay reference is the MX-80. The test device imposes a fixed heat flow in one side of the sample and maintains constant the temperature on the other side. Two samples are tested for symmetry. The samples are unconfined and the total mass of water remains constant. This situation creates a strong thermal gradient in the samples. The final radial strains in some places of the sample, the total vertical strain and the water content distribution will be measured just at the end of the test and some weeks later in order to distinguish the elastic strains from the plastic strains. The test period mustn't be longer than two weeks because a large quantity of water loses through the rubber membrane and the heads of the sample. The maximum temperature reached in the cooper is 90 degrees because with higher temperature, the rubber membrane is damaged. This test is already simulated by a numerical code. Thermal, thermo-hydraulic and thermo-hydro-mechanical analyses are being done. These analyses allow studying the different fluxes inside the sample and its quantification. Water content distribution is compared with the water content calculated from the reference parameters in the clay. The water distribution and the change of diameter after the test will also be studied. This experimental work will allow to know what is the percentage of the strains elastic or plastic and check the mechanical model. The experimental diameter change is compared with the diameter change calculated from the reference parameters of the clay. (authors)
Monitoring elastic strain and damage by neutron and synchrotron beams
International Nuclear Information System (INIS)
Withers, P.J.
2001-01-01
Large-scale neutron and synchrotron X-ray facilities have been providing important information for physicists and chemists for many decades. Increasingly, materials engineers are finding that they can also provide them with important information non-destructively. Highly penetrating neutron and X-ray synchrotron beams provide the materials engineer with a means of obtaining information about the state of stress and damage deep within materials. In this paper the principles underlying the elastic strain measurement and damage characterization techniques are introduced. (orig.)
Analysis of elastic strain and crystallographic texture in poled rhombohedral PZT ceramics
International Nuclear Information System (INIS)
Hall, D.A.; Steuwer, A.; Cherdhirunkorn, B.; Mori, T.; Withers, P.J.
2006-01-01
The elastic strain and crystallographic texture of a rhombohedral lead zirconate titanate ceramic have been characterised in the remanent state, after poling, using high-energy synchrotron X-ray diffraction as a function of the grain orientation ψ relative to the poling direction. It is observed that the (2 0 0) diffraction peak exhibits pronounced shifts as a function of ψ, indicating an elastic lattice strain, while others ({1 1 1}, {1 1 2} and {2 2 0}) show marked changes in intensity as a result of preferred ferroelectric domain orientation. It is shown that the (2 0 0) peak is not affected by the domain switching itself but rather acts like an elastic macrostrain sensor. A simple Eshelby analysis is used to demonstrate that both the elastic strain and texture vary systematically with ψ according to the factor (3cos 2 ψ - 1). This angular dependence is evaluated through micromechanics modelling. The physical meaning of the texture variations with ψ is also discussed
Phase diagrams of ferroelectric nanocrystals strained by an elastic matrix
Nikitchenko, A. I.; Azovtsev, A. V.; Pertsev, N. A.
2018-01-01
Ferroelectric crystallites embedded into a dielectric matrix experience temperature-dependent elastic strains caused by differences in the thermal expansion of the crystallites and the matrix. Owing to the electrostriction, these lattice strains may affect polarization states of ferroelectric inclusions significantly, making them different from those of a stress-free bulk crystal. Here, using a nonlinear thermodynamic theory, we study the mechanical effect of elastic matrix on the phase states of embedded single-domain ferroelectric nanocrystals. Their equilibrium polarization states are determined by minimizing a special thermodynamic potential that describes the energetics of an ellipsoidal ferroelectric inclusion surrounded by a linear elastic medium. To demonstrate the stability ranges of such states for a given material combination, we construct a phase diagram, where the inclusion’s shape anisotropy and temperature are used as two parameters. The ‘shape-temperature’ phase diagrams are calculated numerically for PbTiO3 and BaTiO3 nanocrystals embedded into representative dielectric matrices generating tensile (silica glass) or compressive (potassium silicate glass) thermal stresses inside ferroelectric inclusions. The developed phase maps demonstrate that the joint effect of thermal stresses and matrix-induced elastic clamping of ferroelectric inclusions gives rise to several important features in the polarization behavior of PbTiO3 and BaTiO3 nanocrystals. In particular, the Curie temperature displays a nonmonotonic variation with the ellipsoid’s aspect ratio, being minimal for spherical inclusions. Furthermore, the diagrams show that the polarization orientation with respect to the ellipsoid’s symmetry axis is controlled by the shape anisotropy and the sign of thermal stresses. Under certain conditions, the mechanical inclusion-matrix interaction qualitatively alters the evolution of ferroelectric states on cooling, inducing a structural transition
Asymptotic elastic energy in simple metals
International Nuclear Information System (INIS)
Khalifeh, J.M.
1983-07-01
The asymptotic form of the elastic binding energy ΔEsup(as)(R) between two Mg atoms in Al is expressed as a product of a lattice Green function and the dipole force tensor P. The quantity P is obtained by a nearly free electron model in which the impurity effect is introduced by a screened Ashcroft pseudopotential characterized by an excess charge ΔZ and a core radius rsub(j). (author)
Jiang, Limei; Xu, Xiaofei; Zhou, Yichun
2016-12-01
With the development of the integrated circuit technology and decreasing of the device size, ferroelectric films used in nano ferroelectric devices become thinner and thinner. Along with the downscaling of the ferroelectric film, there is an increasing influence of two strain gradient related terms. One is the strain gradient elasticity and the other one is flexoelectricity. To investigate the interrelationship between flexoelectricity and strain gradient elasticity and their combined effect on the domain structure in ferroelectric nanofilms, a phase field model of flexoelectricity and strain gradient elasticity on the ferroelectric domain evolution is developed based on Mindlin's theory of strain-gradient elasticity. Weak form is derived and implemented in finite element formulations for numerically solving the model equations. The simulation results show that upper bounds for flexoelectric coefficients can be enhanced by increasing strain gradient elasticity coefficients. While a large flexoelectricity that exceeds the upper bound can induce a transition from a ferroelectric state to a modulated/incommensurate state, a large enough strain gradient elasticity may lead to a conversion from an incommensurate state to a ferroelectric state. Strain gradient elasticity and the flexoelectricity have entirely opposite effects on polarization. The observed interrelationship between the strain gradient elasticity and flexoelectricity is rationalized by an analytical solution of the proposed theoretical model. The model proposed in this paper could help us understand the mechanism of phenomena observed in ferroelectric nanofilms under complex electromechanical loads and provide some guides on the practical application of ferroelectric nanofilms.
Elastic energy for reflection-symmetric topologies
International Nuclear Information System (INIS)
Majumdar, A; Robbins, J M; Zyskin, M
2006-01-01
Nematic liquid crystals in a polyhedral domain, a prototype for bistable displays, may be described by a unit-vector field subject to tangent boundary conditions. Here we consider the case of a rectangular prism. For configurations with reflection-symmetric topologies, we derive a new lower bound for the one-constant elastic energy. For certain topologies, called conformal and anticonformal, the lower bound agrees with a previous result. For the remaining topologies, called nonconformal, the new bound is an improvement. For nonconformal topologies we derive an upper bound, which differs from the lower bound by a factor depending only on the aspect ratios of the prism
Elastic interactions between hydrogen atoms in metals. II. Elastic interaction energies
International Nuclear Information System (INIS)
Shirley, A.I.; Hall, C.K.
1986-01-01
The fully harmonic lattice approximation derived in a previous paper is used to calculate the elastic interaction energies in the niobium-hydrogen system. The permanent-direct, permanent-indirect, induced-direct, and induced-indirect forces calculated previously each give rise to a corresponding elastic interaction between hydrogen atoms. The latter three interactions have three- and four-body terms in addition to the usual two-body terms. These quantities are calculated and compared with the corresponding two-body permanent elastic interactions obtained in the harmonic-approximation treatment of Horner and Wagner. The results show that the total induced elastic energy is approximately (1/3) the size of the total permanent elastic energy and opposite to it in sign. The total elastic energy due to three-body interactions is approximately (1/4) the size of the total two-body elastic energy, while the total four-body elastic energy is approximately 5% of the total two-body energy. These additional elastic energies are expected to have a profound effect on the thermodynamic and phase-change behavior of a metal hydride
International Nuclear Information System (INIS)
Wang, S Q; Ye, H Q; Yip, S
2006-01-01
We investigate the stress-strain relationship and elastic stability of zinc-blende GaP, GaN, InP and BN lattices under hydrostatic pressure by first-principles calculation. A simple and direct ab initio implementation for studying the mechanical properties of cubic crystals is developed. The four phases' full-set stress-strain coefficients in wide pressure ranges are theoretically calculated. The fundamental mechanism of elastic stability and the origin of phase transformation under hydrostatic pressure are explored. We found that the abilities for most of these lattices are enhanced to sustain axial strain but weaken to shear strain under higher pressure. The conditions of lattice stability are analysed using both the thermodynamic work-energy criterion and the elastic-stiffness criteria. We show that the lattice collapse of the perfect crystals is caused by the disappearance of their bulk moduli under volume dilation. Lattice defects are considered to be the main reason causing phase transformation under pressure. The correlation between the phonon softening and the variation of elastic coefficients is studied. The pressure dependence of the Kleinman internal strain parameter and its relationship to elastic stability is also explored
Influence of elastic strain on the thermodynamics and kinetics of lithium vacancy in bulk LiCoO2
Moradabadi, Ashkan; Kaghazchi, Payam; Rohrer, Jochen; Albe, Karsten
2018-01-01
The influence of elastic strain on the lithium vacancy formation and migration in bulk LiCoO2 is evaluated by means of first-principles calculations within density functional theory (DFT). Strain dependent energies are determined directly from defective cells and also within linear elasticity theory from the elastic dipole tensor (Gi j) for ground state and saddle point configurations. We analyze finite size effects in the calculation of Gi j, compare the predictions of the linear elastic model with those obtained from direct calculations of defective cells under strain, and discuss the differences. Based on our data, we calculate the variations in vacancy concentration and mobility due to the presence of external strain in bulk LiCoO2 cathodes. Our results reveal that elastic in-plane and out-of-plane strains can significantly change the ionic conductivity of bulk LiCoO2 by up to several orders of magnitude and thus strongly affect the performance of Li-secondary batteries.
Reply to Comment on 'On the importance of the free energy for elasticity under pressure'
International Nuclear Information System (INIS)
Marcus, P M; Qiu, S L
2004-01-01
All criticisms by Steinle-Neumann and Cohen of the correctness of our calculations of equilibrium structure and elastic constants under pressure from the Gibbs free energy are answered and the criticisms are rejected. The difference between the free energy and the internal energy as functions of structure is described to clarify the use of the free energy. The meaning of elastic constants in a system under pressure is discussed in order to derive the basic quadratic expansion of the free energy in the strains. The coefficients in the expansion are the elastic constants under pressure and are in agreement with well-known work. We give reasons why calculations based on the Gibbs free energy are simpler and more accurate than the usual calculations based on minima of the energy at constant volume. (reply)
Proton-proton elastic scattering at ultrahigh energies
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Shaukat, M.A.; Fazal-e-Aleem (University of the Punjab, Lahore (Pakistan). Dept. of Physics)
1981-05-30
The authors use a geometrical model of high-energy pp elastic scattering as proposed by Chou and Yong to analyse experimental data available at present and consider the predictions of the dipole pomeron model for pp elastic scattering at ultrahigh energies. Theoretical results for differential cross sections are compared with experimental data.
Superelastic stress-strain behavior in ferrogels with different types of magneto-elastic coupling
Cremer, Peet; Löwen, Hartmut; Menzel, Andreas M.
Colloidal magnetic particles embedded in an elastic polymer matrix constitute a smart material called ferrogel. It responds to an applied external magnetic field by changes in elastic properties, which can be exploited for various applications like dampers, vibration absorbers, or actuators. Under appropriate conditions, the stress-strain behavior of a ferrogel can display a fascinating feature: superelasticity, the capability to reversibly deform by a huge amount while barely altering the applied load. In a previous work, using numerical simulations, we investigated this behavior assuming that the magnetic moments carried by the embedded particles can freely reorient to minimize their magnetic interaction energy. Here, we extend the analysis to ferrogels where restoring torques by the surrounding matrix hinder rotations towards a magnetically favored configuration. For example, the particles can be chemically cross-linked into the polymer matrix and the magnetic moments can be fixed to the particle axes. We demonstrate that these systems still feature a superelastic regime. As before, the nonlinear stress-strain behavior can be reversibly tailored during operation by external magnetic fields. Yet, the different coupling of the magnetic moments causes different types of response to external stimuli. For instance, an external magnetic field applied parallel to the stretching axis hardly affects the superelastic regime but stiffens the system beyond it. Other smart materials featuring superelasticity, e.g. metallic shape-memory alloys, have already found widespread applications. Our soft polymer systems offer many additional advantages like a typically higher deformability and enhanced biocompatibility combined with high tunability.
An Elastic Plastic Contact Model with Strain Hardening for the LAMMPS Granular Package
Energy Technology Data Exchange (ETDEWEB)
Kuhr, Bryan [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Brake, Matthew Robert [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Component Science and Mechanics; Lechman, Jeremy B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Nanoscale and Reactive Processes
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.
Strain localization and elastic-plastic coupling during deformation of porous sandstone
Energy Technology Data Exchange (ETDEWEB)
Dewers, Thomas A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Issen, Kathleen A. [Clarkson Univ., Potsdam, NY (United States). Mechanical and Aeronautical Engineering; Holcomb, David J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Olsson, William A. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.; Ingraham, Mathew D. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States). Geomechanics Dept.
2017-09-12
Results of axisymmetric compression tests on weak, porous Castlegate Sandstone (Cretaceous, Utah, USA), covering a range of dilational and compactional behaviors, are examined for localization behavior. Assuming isotropy, bulk and shear moduli evolve as increasing functions of mean stress and Mises equivalent shear stress respectively, and as decreasing functions of work-conjugate plastic strains. Acoustic emissions events located during testing show onset of localization and permit calculation of observed shear and low-angle compaction localization zones, or bands, as localization commences. Total strain measured experimentally partitions into: A) elastic strain with constant moduli, B) elastic strain due to stress dependence of moduli, C) elastic strain due to moduli degradation with increasing plastic strain, and D) plastic strain. The third term is the elastic-plastic coupling strain, and though often ignored, contributes significantly to pre-failure total strain for brittle and transitional tests. Constitutive parameters and localization predictions derived from experiments are compared to theoretical predictions. In the brittle regime, predictions of band angles (angle between band normal and maximum compression) demonstrate good agreement with observed shear band angles. Compaction localization was observed in the transitional regime in between shear localization and spatially pervasive compaction, over a small range of mean stresses. In contrast with predictions however, detailed acoustic emissions analyses in this regime show low angle, compaction-dominated but shear-enhanced, localization.
Elastic scattering of low-energy electrons from ammonia
International Nuclear Information System (INIS)
Alle, D.T.; Gulley, R.J.; Buckman, S.J.; Brunger, M.J.
1992-01-01
We report absolute differential cross section measurements for vibrationally elastic electron scattering from NH 3 at incident energies from 2-30 eV. The present results, from a crossed electron-molecular beam apparatus, represent the first comprehensive experimental attempt to quantify the elastic electron-NH 3 scattering process. At each energy studied we have integrated our differential cross section data to generate total elastic and elastic momentum transfer cross sections and a critical comparison of both our differential and integral cross sections against previous experiment and theory is provided. We also report our observation of a strong Feshbach resonance in the elastic channel at an energy of 5.59 ± 0.05 eV. (Author)
Temperature dependence of grain boundary free energy and elastic constants
International Nuclear Information System (INIS)
Foiles, Stephen M.
2010-01-01
This work explores the suggestion that the temperature dependence of the grain boundary free energy can be estimated from the temperature dependence of the elastic constants. The temperature-dependent elastic constants and free energy of a symmetric Σ79 tilt boundary are computed for an embedded atom method model of Ni. The grain boundary free energy scales with the product of the shear modulus times the lattice constant for temperatures up to about 0.75 the melting temperature.
Bulk nonlinear elastic strain waves in a bar with nanosize inclusions
DEFF Research Database (Denmark)
Gula, Igor A.; Samsonov (†), Alexander M.
2018-01-01
We propose a mathematical model for propagation of the long nonlinearly elastic longitudinal strain waves in a bar, which contains nanoscale structural inclusions. The model is governed by a nonlinear doubly dispersive equation (DDE) with respect to the one unknown longitudinal strain function. We...
International Nuclear Information System (INIS)
Mungan, M.; Coppersmith, S.; Vinokur, V.M.
1999-01-01
We analyze the strains near threshold in 1-d charge density wave models at zero temperature and strong pinning. We show that in these models local strains diverge near the depinning threshold and characterize the scaling behavior of the phenomenon. This helps quantify when the underlying elastic description breaks down and plastic effects have to be included
Vattré, A.
2017-08-01
The long- and short-range interactions as well as planar reactions between two infinitely periodic sets of crossing dislocations are investigated using anisotropic elasticity theory in face- (fcc) and body- (bcc) centered cubic materials. Two preliminary cases are proposed to examine the substantial changes in the elastic stress states and the corresponding strain energies due to a slight rearrangement in the internal dislocation geometries and characters. In general, significant differences and discrepancies resulting from the considered cubic crystal structure and the approximation of isotropic elasticity are exhibited. In a third scenario, special attention is paid to connecting specific internal dislocation structures from the previous cases with non-equilibrium configurations predicted by the quantized Frank-Bilby equation for the (111) fcc and (110) bcc twist grain boundaries. The present solutions lead to the formation of energetically favorable dislocation junctions with non-randomly strain-relaxed configurations of lower energy. In particular, the local dislocation interactions and reactions form equilibrium hexagonal-shaped patterns with planar three-fold dislocation nodes without producing spurious far-field stresses.Numerical application results are presented from a selection of cubic metals including aluminum, copper, tantalum, and niobium. In contrast to the fcc materials, asymmetric dislocation nodes occur in the anisotropic bcc cases, within which the minimum-energy paths for predicting the fully strain-relaxed dislocation patterns depend on the Zener anisotropic factor with respect to unity. The associated changes in the dislocation structures as well as the removal of the elastic strain energy upon relaxations are quantified and also discussed.
Boundary value problems of the circular cylinders in the strain-gradient theory of linear elasticity
International Nuclear Information System (INIS)
Kao, B.G.
1979-11-01
Three boundary value problems in the strain-gradient theory of linear elasticity are solved for circular cylinders. They are the twisting of circular cylinder, uniformly pressuring of concentric circular cylinder, and pure-bending of simply connected cylinder. The comparisons of these solutions with the solutions in classical elasticity and in couple-stress theory reveal the differences in the stress fields as well as the apparent stress fields due to the influences of the strain-gradient. These aspects of the strain-gradient theory could be important in modeling the failure behavior of structural materials
Energy in elastic fiber embedded in elastic matrix containing incident SH wave
Williams, James H., Jr.; Nagem, Raymond J.
1989-01-01
A single elastic fiber embedded in an infinite elastic matrix is considered. An incident plane SH wave is assumed in the infinite matrix, and an expression is derived for the total energy in the fiber due to the incident SH wave. A nondimensional form of the fiber energy is plotted as a function of the nondimensional wavenumber of the SH wave. It is shown that the fiber energy attains maximum values at specific values of the wavenumber of the incident wave. The results obtained here are interpreted in the context of phenomena observed in acousto-ultrasonic experiments on fiber reinforced composite materials.
Do we understand elastic scattering up to LHC energies?
International Nuclear Information System (INIS)
Soffer, Jacques
2013-01-01
The measurements of high energy (bar sign)pp and pp elastic at ISR, SPS, and Tevatron colliders have provided usefull informations on the behavior of the scattering amplitude. A large step in energy domain is accomplished with the LHC collider presently running, giving a unique opportunity to improve our knowledge on the asymptotic regime of the elastic scattering amplitude and to verify the validity of our theoretical approach, to describe the total cross section σ tot (s), the total elastic cross section σ el (s), the ratio of the real to imaginary parts of the forward amplitude ρ(s) and the differential cross section dσ (s,t)/dt.
Price and income elasticities of residential energy demand in Germany
International Nuclear Information System (INIS)
Schulte, Isabella; Heindl, Peter
2017-01-01
We apply a quadratic expenditure system to estimate price and expenditure elasticities of residential energy demand (electricity and heating) in Germany. Using official expenditure data from 1993 to 2008, we estimate an expenditure elasticity for electricity of 0.3988 and of 0.4055 for space heating. The own price elasticity for electricity is −0.4310 and −0.5008 in the case of space heating. Disaggregation of households by expenditure and socio-economic composition reveals that the behavioural response to energy price changes is weaker (stronger) for low-income (top-income) households. There are considerable economies of scale in residential energy use but scale effects are not well approximated by the new OECD equivalence scale. Real increases in energy prices show a regressive pattern of incidence, implying that the welfare consequences of direct energy taxation are larger for low income households. The application of zero-elasticities in assessments of welfare consequences of energy taxation strongly underestimates potential welfare effects. The increase in inequality is 22% smaller when compared to the application of disaggregated price and income elasticities as estimated in this paper. - Highlights: • We estimate price, income, and expenditure elasticities for residential energy demand in Germany. • We differentiate elasticities by income groups and household type. • Electricity and space heating are necessary goods since the expenditure elasticities are smaller than unity. • Low-income households show a weaker reaction to changing prices when compared to high-income households. • Direct energy taxation has regressive effects, meaning that larger burdens fall upon low-income households.
Internal strain estimation for quantification of human heel pad elastic modulus: A phantom study.
Holst, Karen; Liebgott, Hervé; Wilhjelm, Jens E; Nikolov, Svetoslav; Torp-Pedersen, Søren T; Delachartre, Philippe; Jensen, Jørgen A
2013-02-01
Shock absorption is the most important function of the human heel pad. However, changes in heel pad elasticity, as seen in e.g. long-distance runners, diabetes patients, and victims of Falanga torture are affecting this function, often in a painful manner. Assessment of heel pad elasticity is usually based on one or a few strain measurements obtained by an external load-deformation system. The aim of this study was to develop a technique for quantitative measurements of heel pad elastic modulus based on several internal strain measures from within the heel pad by use of ultrasound images. Nine heel phantoms were manufactured featuring a combination of three heel pad stiffnesses and three heel pad thicknesses to model the normal human variation. Each phantom was tested in an indentation system comprising a 7MHz linear array ultrasound transducer, working as the indentor, and a connected load cell. Load-compression data and ultrasound B-mode images were simultaneously acquired in 19 compression steps of 0.1mm each. The internal tissue displacement was for each step calculated by a phase-based cross-correlation technique and internal strain maps were derived from these displacement maps. Elastic moduli were found from the resulting stress-strain curves. The elastic moduli made it possible to distinguish eight of nine phantoms from each other according to the manufactured stiffness and showed very little dependence of the thickness. Mean elastic moduli for the three soft, the three medium, and the three hard phantoms were 89kPa, 153kPa, and 168kPa, respectively. The combination of ultrasound images and force measurements provided an effective way of assessing the elastic properties of the heel pad due to the internal strain estimation. Copyright © 2012 Elsevier B.V. All rights reserved.
Caro, M A; Schulz, S; O'Reilly, E P
2013-01-16
We explore the calculation of the elastic properties of zinc-blende and wurtzite semiconductors using two different approaches: one based on stress and the other on total energy as a function of strain. The calculations are carried out within the framework of density functional theory in the local density approximation, with the plane wave-based package VASP. We use AlN as a test system, with some results also shown for selected other materials (C, Si, GaAs and GaN). Differences are found in convergence rate between the two methods, especially in low symmetry cases, where there is a much slower convergence for total energy calculations with respect to the number of plane waves and k points used. The stress method is observed to be more robust than the total energy method with respect to the residual error in the elastic constants calculated for different strain branches in the systems studied.
Theoretical aspects of high energy elastic nucleon scattering
Kundrat, Vojtech; Lokajicek, Milos
2010-01-01
The eikonal model must be denoted as strongly preferable for the analysis of elastic high-energy hadron collisions. The given approach allows to derive corresponding impact parameter profiles that characterize important physical features of nucleon collisions, e.g., the range of different forces. The contemporary phenomenological analysis of experimental data is, however, not able to determine these profiles unambiguously, i.e., it cannot give the answer whether the elastic hadron collisions are more central or more peripheral than the inelastic ones. However, in the collisions of mass objects (like protons) the peripheral behavior of elastic collisions should be preferred.
Energy efficiency in elastic-bandwidth optical networks
DEFF Research Database (Denmark)
Vizcaino, Jorge Lopez; Ye, Yabin; Tafur Monroy, Idelfonso
2011-01-01
of elastic bandwidth allocation, opens new horizons in the operation of optical networks. In this paper, we compare the network planning problem in an elastic bandwidth CO-OFDM-based network and a fixed-grid WDM network. We highlight the benefits that bandwidth elasticity and the selection of different......The forecasted growth in the Internet traffic has made the operators and industry to be concerned about the power consumption of the networks, and to become interested in alternatives to plan and operate the networks in a more energy efficient manner. The introduction of OFDM, and its property...
Short- and long-run elasticities in energy demand
International Nuclear Information System (INIS)
Bentzen, J.; Engsted, T.
1993-01-01
Short- and long-run energy demand elasticities are estimated on Danish annual data for 1948-90. Energy consumption, the real price of energy and real GDP appear to be non-stationary variables. Cointegration and error-correction methods are therefore applied. All estimated parameters have the expected signs and magnitudes and no evidence is found of a structural break in energy demand caused by the increases in real energy prices since 1973/74. (author)
Optimization of directional elastic energy propagation
DEFF Research Database (Denmark)
Andreassen, Erik; Chang, Hannah R.; Ruzzene, Massimo
2016-01-01
The aim of this paper is to demonstrate how topology optimization can be used to design a periodically perforated plate, in order to obtain a tailored anisotropic group velocity profile. The main method is demonstrated on both low and high frequency bending wave propagation in an aluminum plate......, but is general in the sense that it could be used to design periodic structures with frequency dependent group velocity profiles for any kind of elastic wave propagation. With the proposed method the resulting design is manufacturable. Measurements on an optimized design compare excellently with the numerical...
Analysis of elastic interactions of hadrons at high energies
International Nuclear Information System (INIS)
Yuldashev, B.S.; Fazilova, Z.F.; Ismatov, E.I.; Kurmanbai, M.S.; Ajniyazova, G.T.; Tskhay, K.V.; Medeuova, A.B.
2004-01-01
Study of elastic interactions of hadrons at high energies if of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory - unitarity condition of scattering matrix - elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interactions at high-energies, as well as for results prediction. By using experimental data on differential cross-section of elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude δ(t) the t-dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag form of differential cross-section of elastic pp(p) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of the scaling the general expressions for s- and t-dependences of inelastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadrons scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied. (author)
Analysis of elastic interactions of hadrons at high energies
International Nuclear Information System (INIS)
Fazylov, M.I.; Yuldashev, B.S.; Azhniyazova, G.T.; Ismatov, E.I.; Sartbay, T.; Kurmanbay, M.S.; Tskhay, K.V.
2004-01-01
Full text: Study of elastic interactions of hadrons at high energies if of great interest due to the fact that the amplitude of this process is the simplest, and at the same time, it is a fundamental object for theoretical and experimental researches. Study of this process allows one to have a quantitative check of various theories and models, and to make a critical selection. By using of fundamental property of theory - unitarity condition of scattering matrix - elastic scattering can be connected with inelastic reaction. Based on S-channel unitarity condition expressing elastic amplitude via inelastic overlapping function, to study the latter, as well as to describe the experimentally measured characteristics of hadron-nucleon interactions at high-energies, as well as for results prediction. By using experimental data on differential cross-section of elastic scattering of hadrons at various energies and by theoretical information on ratio of a real part and an imaginary part of scattering amplitude δ(t) the t-dependence of inelastic and elastic overlapping functions is studied. Influence of a zigzag form of differential cross-section of elastic pp(p) scattering on profile function and inelastic overlapping function to violation of geometric scaling was studied. In frames of the scaling the general expressions for s- and t-dependences of inelastic overlapping function are derived. Comparison of this function in three elastic scattering models was carried out. It was demonstrated that one would need to assume that hadrons become blacker at central part in order to correctly describe experimental angular distribution data. Dependence of differential cross-section on transfer momentum square for elastic hadrons scattering at energies of ISR and SPS in the model of inelastic overlapping function is studied
Study on elastic-plastic deformation analysis using a cyclic stress-strain curve
International Nuclear Information System (INIS)
Igari, Toshihide; Setoguchi, Katsuya; Yamauchi, Masafumi
1983-01-01
This paper presents the results of the elastic-plastic deformation analysis using a cyclic stress-strain curve with an intention to apply this method for predicting the low-cycle fatigue life. Uniaxial plastic cycling tests were performed on 2 1/4Cr-1Mo steel to investigate the correspondence between the cyclic stress-strain curve and the hysteresis loop, and also to determine what mathematical model should be used for analysis of deformation at stress reversal. Furthermore, a cyclic in-plane bending test was performed on a flat plate to clarify the validity of the cyclic stress-strain curve-based theoretical analysis. The results obtained are as follows: (1) The cyclic stress-strain curve corresponds nearly to the ascending curve of hysteresis loop scaled by a factor of 1/2 for both stress and strain. Therefore, the cyclic stress-strain curve can be determined from the shape of hysteresis loop, for simplicity. (2) To perform the elastic-plastic deformation analysis using the cyclic stress-strain curve is both practical and effective for predicting the cyclic elastic-plastic deformation of structures at the stage of advanced cycles. And Masing model can serve as a suitable mathematical model for such a deformation analysis. (author)
Strain fields and line energies of dislocations in uranium dioxide
International Nuclear Information System (INIS)
Parfitt, David C; Bishop, Clare L; Wenman, Mark R; Grimes, Robin W
2010-01-01
Computer simulations are used to investigate the stability of typical dislocations in uranium dioxide. We explain in detail the methods used to produce the dislocation configurations and calculate the line energy and Peierls barrier for pure edge and screw dislocations with the shortest Burgers vector 1/2 . The easiest slip system is found to be the {100}(110) system for stoichiometric UO 2 , in agreement with experimental observations. We also examine the different strain fields associated with these line defects and the close agreement between the strain field predicted by atomic scale models and the application of elastic theory. Molecular dynamics simulations are used to investigate the processes of slip that may occur for the three different edge dislocation geometries and nudged elastic band calculations are used to establish a value for the Peierls barrier, showing the possible utility of the method in investigating both thermodynamic average behaviour and dynamic processes such as creep and plastic deformation.
Reza Barati, Mohammad
2017-09-01
For the first time, a vibrating porous double-nanoplate system under in-plane periodic loads is modeled via the generalized nonlocal strain gradient theory (NSGT). Based on the proposed theory, one can examine both stiffness-softening and stiffness-hardening effects for a more accurate analysis of nanoplates. Nanopores or nanovoids are incorporated to the model based on a modified rule of mixture. Modeling of porous double-layered nanoplate is conducted according to a refined four-variable plate theory with fewer field variables than first-order plate theory. The governing equations and related classical and nonclassical boundary conditions are derived based on Hamilton's principle. These equations are solved for hinged nanoplates via Galerkin's method. It is shown that porosities, nonlocal parameter, strain gradient parameter, material gradation, interlayer stiffness, elastic foundation, side-to-thickness and aspect ratios have a notable impact on the vibration behavior of nanoporous materials.
Elastic layer under axisymmetric indentation and surface energy effects
Intarit, Pong-in; Senjuntichai, Teerapong; Rungamornrat, Jaroon
2018-04-01
In this paper, a continuum-based approach is adopted to investigate the contact problem of an elastic layer with finite thickness and rigid base subjected to axisymmetric indentation with the consideration of surface energy effects. A complete Gurtin-Murdoch surface elasticity is employed to consider the influence of surface stresses. The indentation problem of a rigid frictionless punch with arbitrary axisymmetric profiles is formulated by employing the displacement Green's functions, derived with the aid of Hankel integral transform technique. The problem is solved by assuming the contact pressure distribution in terms of a linear combination of admissible functions and undetermined coefficients. Those coefficients are then obtained by employing a collocation technique and an efficient numerical quadrature scheme. The accuracy of proposed solution technique is verified by comparing with existing solutions for rigid indentation on an elastic half-space. Selected numerical results for the indenters with flat-ended cylindrical and paraboloidal punch profiles are presented to portray the influence of surface energy effects on elastic fields of the finite layer. It is found that the presence of surface stresses renders the layer stiffer, and the size-dependent behavior of elastic fields is observed in the present solutions. In addition, the surface energy effects become more pronounced with smaller contact area; thus, the influence of surface energy cannot be ignored in the analysis of indentation problem especially when the indenter size is very small such as in the case of nanoindentation.
Measuring the elastic strain of individual grains in polycrystalline materials
DEFF Research Database (Denmark)
AllB, which fits centre-of-mass grain positions, orientations and strain tensors from the experimental far-field 3DXRD data, was developed. The program builds on peaksearch, ImageD11 and GrainSpotter and will eventually be implemented in the Fable GUI. By the use of simulated data the presentation will focus...... a careful calibration of the global parameters relating to the experiment (sample-to-detector distance, tilts of detector and sample and beam centre on detector) must be performed. For this purpose the option of fitting the global parameters simultaneously for any number of indexed grains is included in Fit...
Internal strain estimation for quantification of human heel pad elastic modulus: A phantom study
DEFF Research Database (Denmark)
Holst, Karen; Liebgott, Hervé; Wilhjelm, Jens E.
2013-01-01
Shock absorption is the most important function of the human heel pad. However, changes in heel pad elasticity, as seen in e.g. long-distance runners, diabetes patients, and victims of Falanga torture are affecting this function, often in a painful manner. Assessment of heel pad elasticity...... is usually based on one or a few strain measurements obtained by an external load-deformation system. The aim of this study was to develop a technique for quantitative measurements of heel pad elastic modulus based on several internal strain measures from within the heel pad by use of ultrasound images. Nine...... heel phantoms were manufactured featuring a combination of three heel pad stiffnesses and three heel pad thicknesses to model the normal human variation. Each phantom was tested in an indentation system comprising a 7MHz linear array ultrasound transducer, working as the indentor, and a connected load...
Plane strain analytical solutions for a functionally graded elastic-plastic pressurized tube
International Nuclear Information System (INIS)
Eraslan, Ahmet N.; Akis, Tolga
2006-01-01
Plane strain analytical solutions to functionally graded elastic and elastic-plastic pressurized tube problems are obtained in the framework of small deformation theory. The modulus of elasticity and the uniaxial yield limit of the tube material are assumed to vary radially according to two parametric parabolic forms. The analytical plastic model is based on Tresca's yield criterion, its associated flow rule and ideally plastic material behaviour. Elastic, partially plastic and fully plastic stress states are investigated. It is shown that the elastoplastic response of the functionally graded pressurized tube is affected significantly by the material nonhomogeneity. Different modes of plasticization may take place unlike the homogeneous case. It is also shown mathematically that the nonhomogeneous elastoplastic solution presented here reduces to that of a homogeneous one by appropriate choice of the material parameters
Fatigue analysis - computation of the actual strain range using elastic calculation
International Nuclear Information System (INIS)
Roche, R.L.
1987-04-01
The design codes used in nuclear industry do not contain all the same rules allowing to deduce from an elastic calculation the actual deformation variation. Knowledge of strain range is needed for fatigue analysis. Elastic calculation does not give the actual range. The aim of this paper is discussing ways to correct elastic results and proposing a practical method to do it. Two corrections are required. The first one is related to elastic follow up effect when shakedown is not obtained (correction on secondary stress). The second one is related to stress raisers effect (correction on peak stress). It is shown that NEUBER's rule is not convenient for the second correction when shakedown is not fulfilled [fr
A theoretical analysis of price elasticity of energy demand in multistage energy conversion systems
International Nuclear Information System (INIS)
Lowe, R.
2003-01-01
The objective of this paper is an analytical exploration of the problem of price elasticity of energy demand in multi-stage energy conversion systems. The paper describes in some detail an analytical model of energy demand in such systems. Under a clearly stated set of assumptions, the model makes it possible to explore both the impacts of the number of sub-systems, and of varying sub-system elasticities on overall system elasticity. The analysis suggests that overall price elasticity of energy demand for such systems will tend asymptotically to unity as the number of sub-systems increases. (author)
A theoretical analysis of price elasticity of energy demand in multi-stage energy conversion systems
International Nuclear Information System (INIS)
Lowe, Robert
2003-01-01
The objective of this paper is an analytical exploration of the problem of price elasticity of energy demand in multi-stage energy conversion systems. The paper describes in some detail an analytical model of energy demand in such systems. Under a clearly stated set of assumptions, the model makes it possible to explore both the impacts of the number of sub-systems, and of varying sub-system elasticities on overall system elasticity. The analysis suggests that overall price elasticity of energy demand for such systems will tend asymptotically to unity as the number of sub-systems increases
Deuteron-deuteron elastic scattering at high energies
International Nuclear Information System (INIS)
Fazal-e-Aleem; Ali, S.
1991-01-01
The eikonal picture which has theoretical foundations in some areas of physics has been successful in explaining various aspects of elastic scattering at high energies. Chou and Yang first proposed a preliminary version of the eikonal model for hadron-hadron elastic scattering. The model is based on geometrical considerations in which hadrons are treated as extended objects. Elastic scattering then results from the propagation of attenuated wave function. By assuming that at high energies the scattering amplitude is purely imaginary and that the hadronic matter distribution is proportional to the charge distribution on protons, Durand and Lipes studied high energy pp scattering on the basis of this prestine model. Later on, the model was extended to other elastic reactions. However, a survey of literature shows that it has been successful only in the diffraction peak region. It has been shown that the pristine Chou-Yange model can explain the differential cross section for deuteron-deuteron elastic scattering at √s = 53 GeV in the diffraction peak region. In order to fit the large momentum transfer data, the generalized Chou-Yang model is used
Elastic diffraction interactions of hadrons at high energies
International Nuclear Information System (INIS)
Ismatov, E.I.; Ubaev, J.K.; Tshay, K.V.; Zholdasova, S.M.; Juraev, Sh.Kh.; Essaniazov, Sh.P.
2006-01-01
Full text: 1. The diffraction theory of elastic and inelastic scattering of hadron-hadron and hadron-nucleus processes is developed. The description of experimental data on differential cross section of elastic scattering p p, p-bar p in wide range of transferred momentum is made in the frames of the developed inelastic overlap function model. The investigation of nuclei elastic scattering at the low, middle and high energies is carried out, that allowed to execute quantitative control of efficiency or quantum-field and phenomenological theories and make critical analysis of their utility. The principle of construction of realistic amplitudes of the elastic scattering is confirmed on the basic of the s- and t-channel approaches both conditions stationary of amplitudes. For a wide range of models the comparative analysis of amplitude of inelastic scattering in representation of impact parameter is executed. The expression for effective radius of interaction, effective trajectory Regge and slope of inelastic function of overlapping are analysed. In diffraction approximation the satisfactory description of the data on hadrons interaction at the energy of tens GeV with proton and deuterons is received. The features of spectra of fast particles are analysed. The theory of collective variables S, T, P which characterize a deviation degree of angular distribution of particles from spherical symmetry, the general formula for dispersion of any density of obtained, the particles decays are investigated [1-2]. 2. The solution of Lippmann-Schwinger equation investigated within the frameworks of frameworks of high -energy approximation satisfies the generalized Huygens principle used in the diffraction theory nuclear processes. The diffraction emission is considered at the interaction of charged hadrons one with another and the nuclei [3]. 3. Study of elastic interactions of hadrons at high energies is of great interest due to the fact that the amplitude of this process is the
Local, atomic-level elastic strain measurements of metallic glass thin films by electron diffraction
Energy Technology Data Exchange (ETDEWEB)
Ebner, C. [Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna (Austria); Sarkar, R. [Department of Materials Science and Engineering, School for Engineering of Matter Transport and Energy, Arizona State University, Tempe 85287 (United States); Rajagopalan, J. [Department of Materials Science and Engineering, School for Engineering of Matter Transport and Energy, Arizona State University, Tempe 85287 (United States); Department of Mechanical and Aerospace Engineering, School for Engineering of Matter Transport and Energy, Arizona State University, Tempe 85287 (United States); Rentenberger, C., E-mail: christian.rentenberger@univie.ac.at [Physics of Nanostructured Materials, Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Vienna (Austria)
2016-06-15
A novel technique is used to measure the atomic-level elastic strain tensor of amorphous materials by tracking geometric changes of the first diffuse ring of selected area electron diffraction patterns (SAD). An automatic procedure, which includes locating the centre and fitting an ellipse to the diffuse ring with sub-pixel precision is developed for extracting the 2-dimensional strain tensor from the SAD patterns. Using this technique, atomic-level principal strains from micrometre-sized regions of freestanding amorphous Ti{sub 0.45}Al{sub 0.55} thin films were measured during in-situ TEM tensile deformation. The thin films were deformed using MEMS based testing stages that allow simultaneous measurement of the macroscopic stress and strain. The calculated atomic-level principal strains show a linear dependence on the applied stress, and good correspondence with the measured macroscopic strains. The calculated Poisson’s ratio of 0.23 is reasonable for brittle metallic glasses. The technique yields a strain accuracy of about 1×10{sup −4} and shows the potential to obtain localized strain profiles/maps of amorphous thin film samples. - Highlights: • A TEM method to measure elastic strain in metallic glass films is proposed. • Method is based on tracking geometric changes in TEM diffraction patterns. • An automatic procedure is developed for extracting the local strain tensor. • Atomic-level strain in amorphous TiAl film was analysed during in-situ deformation. • Capability of the method to obtain micrometer scale strain profiles/maps is shown.
Proton-proton elastic scattering at ultrahigh energies
International Nuclear Information System (INIS)
Saleem, M.; Shaukat, M.A.; Fazal-e-Aleem
1981-01-01
Recent experimental results on proton-proton elastic scattering at high energies are discussed in the context of the comments by Chou and Yang. There does not appear to be any tendency that the experimental results would agree with the predictions of the geometrical model even at ultrahigh energies. The angular distribution structure as described by using the dipole pomeron is consistent with the experimental data at presently available high energies and predicts results quite different from the geometrical model. (author)
Proton-proton elastic scattering at ultrahigh energies
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Shaukat, M.A.; Fazal-e-Aleem (University of the Punjab, Lahore (Pakistan). Dept. of Physics)
1981-05-30
Recent experimental results on proton-proton elastic scattering at high energies are discussed in the context of the comments by Chou and Yang. There does not appear to be any tendency that the experimental results would agree with the predictions of the geometrical model even at ultrahigh energies. The angular distribution structure as described by using the dipole pomeron is consistent with the experimental data at presently available high energies and predicts results quite different from the geometrical model.
Do we understand elastic scattering up to LHC energies?
Energy Technology Data Exchange (ETDEWEB)
Soffer, Jacques [Physics Department, Temple University, Philadelphia, PA 19122-6082 (United States)
2013-04-15
The measurements of high energy (bar sign)pp and pp elastic at ISR, SPS, and Tevatron colliders have provided usefull informations on the behavior of the scattering amplitude. A large step in energy domain is accomplished with the LHC collider presently running, giving a unique opportunity to improve our knowledge on the asymptotic regime of the elastic scattering amplitude and to verify the validity of our theoretical approach, to describe the total cross section {sigma}{sub tot}(s), the total elastic cross section {sigma}{sub el}(s), the ratio of the real to imaginary parts of the forward amplitude {rho}(s) and the differential cross section d{sigma} (s,t)/dt.
Measurements of radiated elastic wave energy from dynamic tensile cracks
Boler, Frances M.
1990-01-01
The role of fracture-velocity, microstructure, and fracture-energy barriers in elastic wave radiation during a dynamic fracture was investigated in experiments in which dynamic tensile cracks of two fracture cofigurations of double cantilever beam geometry were propagating in glass samples. The first, referred to as primary fracture, consisted of fractures of intact glass specimens; the second configuration, referred to as secondary fracture, consisted of a refracture of primary fracture specimens which were rebonded with an intermittent pattern of adhesive to produce variations in fracture surface energy along the crack path. For primary fracture cases, measurable elastic waves were generated in 31 percent of the 16 fracture events observed; the condition for radiation of measurable waves appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For secondary fractures, 100 percent of events showed measurable elastic waves; in these fractures, the ratio of radiated elastic wave energy in the measured component to fracture surface energy was 10 times greater than for primary fracture.
Neutron-proton elastic scattering at high energies
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Fazal-e-Aleem (Punjab Univ., Lahore (Pakistan). Dept. of Physics)
1980-09-06
The most recent measurements of the differential and total cross sections of neutron-proton elastic scattering from 70 to 400 GeV/c have been explained by using rho as a simple pole and pomeron as a dipole. The predictions are also made regarding the energy dependence of dip and bump structure in angular distribution.
Elastic scattering of low energy γ-rays
International Nuclear Information System (INIS)
Whittingham, I.B.
1978-01-01
The current status of the theory of the elastic scattering of low energy γ rays is reviewed and a detailed analysis of the theoretical background to the recent calculation of Rayleigh scattering by W.R.Johnson and co-workers is presented
Ilton, Mark; Cox, Suzanne; Egelmeers, Thijs; Patek, S. N.; Crosby, Alfred J.
Impulsive biological systems - which include mantis shrimp, trap-jaw ants, and venus fly traps - can reach high speeds by using elastic elements to store and rapidly release energy. The material behavior and shape changes critical to achieving rapid energy release in these systems are largely unknown due to limitations of materials testing instruments operating at high speed and large displacement. In this work, we perform fundamental, proof-of-concept measurements on the tensile retraction of elastomers. Using high speed imaging, the kinematics of retraction are measured for elastomers with varying mechanical properties and geometry. Based on the kinematics, the rate of energy dissipation in the material is determined as a function of strain and strain-rate, along with a scaling relation which describes the dependence of maximum velocity on material properties. Understanding this scaling relation along with the material failure limits of the elastomer allows the prediction of material properties required for optimal performance. We demonstrate this concept experimentally by optimizing for maximum velocity in our synthetic model system, and achieve retraction velocities that exceed those in biological impulsive systems. This model system provides a foundation for future work connecting continuum performance to molecular architecture in impulsive systems.
Dislocations, the elastic energy momentum tensor and crack propagation
International Nuclear Information System (INIS)
Lung, Chi-wei
1979-07-01
Based upon dislocation theory, some stress intensity factors can be calculated for practical cases. The results obtained by this method have been found to agree fairly well with the results obtained by the conventional fracture mechanics. The elastic energy momentum tensor has been used to calculate the force acting on the crack tip. A discussion on the kinetics of migration of impurities to the crack tip was given. It seems that the crack tip sometimes may be considered as a singularity in an elastic field and the fundamental law of classical field theory is applicable on the problem in fracture of materials. (author)
Dynamic energy release rate in couple-stress elasticity
International Nuclear Information System (INIS)
Morini, L; Piccolroaz, A; Mishuris, G
2013-01-01
This paper is concerned with energy release rate for dynamic steady state crack problems in elastic materials with microstructures. A Mode III semi-infinite crack subject to loading applied on the crack surfaces is considered. The micropolar behaviour of the material is described by the theory of couple-stress elasticity developed by Koiter. A general expression for the dynamic J-integral including both traslational and micro-rotational inertial contributions is derived, and the conservation of this integral on a path surrounding the crack tip is demonstrated
Elastic positron-cadmium scattering at low energies
International Nuclear Information System (INIS)
Bromley, M. W. J.; Mitroy, J.
2010-01-01
The elastic and annihilation cross sections for positron-cadmium scattering are reported up to the positronium-formation threshold (at 2.2 eV). The low-energy phase shifts for the elastic scattering of positrons from cadmium were derived from the bound and pseudostate energies of a very large basis configuration-interaction calculation of the e + -Cd system. The s-wave binding energy is estimated to be 126±42 meV, with a scattering length of A scat =(14.2±2.1)a 0 , while the threshold annihilation parameter, Z eff , was 93.9±26.5. The p-wave phase shift exhibits a weak shape resonance that results in a peak Z eff of 91±17 at a collision energy of about 490±50 meV.
Anisotropic chemical strain in cubic ceria due to oxygen-vacancy-induced elastic dipoles.
Das, Tridip; Nicholas, Jason D; Sheldon, Brian W; Qi, Yue
2018-06-06
Accurate characterization of chemical strain is required to study a broad range of chemical-mechanical coupling phenomena. One of the most studied mechano-chemically active oxides, nonstoichiometric ceria (CeO2-δ), has only been described by a scalar chemical strain assuming isotropic deformation. However, combined density functional theory (DFT) calculations and elastic dipole tensor theory reveal that both the short-range bond distortions surrounding an oxygen-vacancy and the long-range chemical strain are anisotropic in cubic CeO2-δ. The origin of this anisotropy is the charge disproportionation between the four cerium atoms around each oxygen-vacancy (two become Ce3+ and two become Ce4+) when a neutral oxygen-vacancy is formed. Around the oxygen-vacancy, six of the Ce3+-O bonds elongate, one of the Ce3+-O bond shorten, and all seven of the Ce4+-O bonds shorten. Further, the average and maximum chemical strain values obtained through tensor analysis successfully bound the various experimental data. Lastly, the anisotropic, oxygen-vacancy-elastic-dipole induced chemical strain is polarizable, which provides a physical model for the giant electrostriction recently discovered in doped and non-doped CeO2-δ. Together, this work highlights the need to consider anisotropic tensors when calculating the chemical strain induced by dilute point defects in all materials, regardless of their symmetry.
Systematics of elastic scattering at high and intermediate energy
Energy Technology Data Exchange (ETDEWEB)
Dias De Deus, J [Instituto de Fisica e Matematica, Lisboa (Portugal); Kroll, P [Wuppertal Univ. (Gesamthochschule) (Germany, F.R.)
1977-01-01
A model for elastic scattering valid in the intermediate and high-energy region is proposed. The model includes three kinds of entities: the pomeron, a universal GS pomeron; the reggeons, also universal and of GS type; and the core, a low-energy central real piece required by dispersion relations. The number of free functions and parameters is rather small. The approach supports naive duality and, in general, agrees with the results of absorptive models.
Energy and depth resolution in elastic recoil coincidence spectrometry
Energy Technology Data Exchange (ETDEWEB)
Szilagyi, E., E-mail: szilagyi@rmki.kfki.h [KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest (Hungary)
2010-06-15
Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.
Energy and depth resolution in elastic recoil coincidence spectrometry
International Nuclear Information System (INIS)
Szilagyi, E.
2010-01-01
Elastic recoil coincidence spectrometry was implemented into the analytical ion beam simulation program DEPTH. In the calculations, effective detector geometry and multiple scattering effects are considered. Mott's cross section for the identical, spin zero particles is included. Spectra based on the individual detector signal and summing the energy of the recoiled and scattered particles originating from the same scattering events can also be calculated. To calculate this latter case, the dependency of the energy spread contributions had to be reconsidered.
Singlet channel coupling in deuteron elastic scattering at intermediate energies
International Nuclear Information System (INIS)
Al-Khalili, J.S.; Tostevin, J.A.; Johnson, R.C.
1990-01-01
Intermediate energy deuteron elastic scattering is investigated in a three-body model incorporating relativistic kinematics. The effects of deuteron breakup to singlet spin intermediate states, on the elastic scattering observables for the 58 Ni(d vector, d) 58 Ni reaction at 400 and 700 MeV, are studied quantitatively. The singlet-breakup contributions to the elastic amplitude are estimated within an approximate two-step calculation. The calculation makes an adiabatic approximation in the intermediate states propagator which allows the use of closure over the np intermediate states continuum. The singlet channel coupling is found to produce large effects on the calculated reaction tensor analysing power A yy , characteristic of a dynamically induced second-rank tensor interaction. By inspection of the calculated breakup amplitudes we show this induced interaction to be of the T L tensor type. (orig.)
Fault on-off versus strain rate and earthquakes energy
Directory of Open Access Journals (Sweden)
C. Doglioni
2015-03-01
Full Text Available We propose that the brittle-ductile transition (BDT controls the seismic cycle. In particular, the movements detected by space geodesy record the steady state deformation in the ductile lower crust, whereas the stick-slip behavior of the brittle upper crust is constrained by its larger friction. GPS data allow analyzing the strain rate along active plate boundaries. In all tectonic settings, we propose that earthquakes primarily occur along active fault segments characterized by relative minima of strain rate, segments which are locked or slowly creeping. We discuss regional examples where large earthquakes happened in areas of relative low strain rate. Regardless the tectonic style, the interseismic stress and strain pattern inverts during the coseismic stage. Where a dilated band formed during the interseismic stage, this will be shortened at the coseismic stage, and vice-versa what was previously shortened, it will be dilated. The interseismic energy accumulation and the coseismic expenditure rather depend on the tectonic setting (extensional, contractional, or strike-slip. The gravitational potential energy dominates along normal faults, whereas the elastic energy prevails for thrust earthquakes and performs work against the gravity force. The energy budget in strike-slip tectonic setting is also primarily due elastic energy. Therefore, precursors may be different as a function of the tectonic setting. In this model, with a given displacement, the magnitude of an earthquake results from the coseismic slip of the deformed volume above the BDT rather than only on the fault length, and it also depends on the fault kinematics.
International Nuclear Information System (INIS)
Vaccaro, F.P.; Hehemann, R.F.; Troiano, A.R.
1979-08-01
The influence of elastic (stress) and plastic (cold work) strains on the stress corrosion cracking of a transformable austenitic stainless steel was studied in several aqueous chloride environments. Initial polarization behavior was active for all deformation conditions as well as for the annealed state. Visual observation, potential-time, and current-time curves indicated the development of a pseudo-passive (flawed) film leading to localized corrosion, occluded cells and SCC. SCC did not initiate during active corrosion regardless of the state of strain unless severe low temperature deformation produced a high percentage of martensite. Both elastic and plastic deformation increased the sensitivity to SCC when examined on the basis of percent yield strength. The corrosion potential, the critical cracking potential, and the potential at which the current changes from anodic to cathodic were essentially unaffected by deformation. It is apparent that the basic electrochemical parameters are independent of the bulk properties of the alloy and totally controlled by surface phenomena
Fatigue analysis - computation of the actual strain range using elastic calculations (factor Ke)
International Nuclear Information System (INIS)
Roche, R.L.
1987-01-01
Pressure vessels are not eternal, their life is not endless, but must be long enough for profitable use. Fatigue is the most important damage limiting life time. It is due to variable loading and especially to deformation-controlled loading like thermal dilatation (thermal stress). Hence, it is of prime importance to perform an fatigue analysis in the design phase in order to be sure the pressure vessel life meet requirement of the design specification. It is also useful to perform such an analysis for assessing the remaining life. To compute the fatigue damage, knowledge of the strain range is needed. As calculation taking into account non linear behavior of the material are very expensive and not always reliable, the current practice is using elastic computation. The aim of this paper is to discuss the methods for correcting the elastically calculated strain range and to propose a sound and practical method
A 3D Orthotropic Strain-Rate Dependent Elastic Damage Material Model.
Energy Technology Data Exchange (ETDEWEB)
English, Shawn Allen
2014-09-01
A three dimensional orthotropic elastic constitutive model with continuum damage and cohesive based fracture is implemented for a general polymer matrix composite lamina. The formulation assumes the possibility of distributed (continuum) damage followed b y localized damage. The current damage activation functions are simply partially interactive quadratic strain criteria . However, the code structure allows for changes in the functions without extraordinary effort. The material model formulation, implementation, characterization and use cases are presented.
Stress-strain state of the elastic strip with nearly rectangular cross section
Minaeva, N. V.
2018-03-01
The article considers behavior of elastic strip in the framework of plane strain under compression. Conditions are formulated in integral form on the boundaries where the forces are imposed. All the boundary conditions are imposed on the boundary of the body in the strained state, which is necessary for investigating the continuous dependence of the solution to the corresponding task on the functions describing the difference between the shape of cross-section of the strip and a rectangle. The study of the analyticity of the problem solution with respect to small near zero parameters is carried out. The solution is found by perturbation method up to the first order of terms.
International Nuclear Information System (INIS)
Fernandez-Saez, J.; Luna de, S.; Rubio, L.; Perez-Castellanos, J. L.; Navarro, C.
2001-01-01
An earlier paper dealt with the experimental techniques used to determine the dynamic fracture properties of linear elastic materials. Here we describe those most commonly used as elastoplastic materials, limiting the study to the initiation fracture toughness at the intermediate strain rate (of around 10''2 s''-1). In this case the inertial forces are negligible and it is possible to apply the static solutions. With this stipulation, the analysis can be based on the methods of testing in static conditions. The dynamic case differs basically, from the static one, in the influence of the strain rate on the properties of the material. (Author) 57 refs
Elastic-plastic analysis of local and integral straining behaviour in a cracked plate
International Nuclear Information System (INIS)
Grueter, L.; Ruettenauer, B.
1982-01-01
For components of the primary coolant system of the German LMFBR prototype reactor SNR-300, integrity against anticipated accidents (Bethe-Tait) has to be shown for a cracked structure. Within this programme a number of tests with cracked wide plate specimens yielding overall limit strains of approximately 15% have been run; finite element calculations have been infinated for the wide plate geometry. The paper discusses the straining behaviour of a cracked plate by considering the numerical simulation of structures strained up to such high levels. The stress-strain diagram of the weldment of the austenitic stainless steel X6 CrNi 18 at 450 0 C has been used. Plane strain and stress conditions have been prescribed. The original plate dimensions (t = thickness = 40 mm; h = height = 400 mm) have been used as well as a similar, but smaller plate of t = 8.8 mm width. The crack length is defined as 0.1 t. The results show that for a cracked plate under high plastic strain the near-crack-tip-field values still govern the structural mechanical behaviour. Concerning the absolute dimensions the effects known for elasticity retain their influence in the plastic regime; however, the crack location becomes more unimportant with increasing strain, i.e. the appropriate pure geometry factor tends to unity in the plastic regime. The center-crack, defined as 2a = 0.1 t, corresponds to an equivalent edge crack of depth a = 0.05 t in the elastic case. It can be shown that for high plastic strains this correspondence remains fully valid. (orig.)
Directory of Open Access Journals (Sweden)
Azuma Takahashi
Full Text Available The mechanical interaction between blood vessels and medical devices can induce strains in these vessels. Measuring and understanding these strains is necessary to identify the causes of vascular complications. This study develops a method to measure the three-dimensional (3D distribution of strain using tomographic particle image velocimetry (Tomo-PIV and compares the measurement accuracy with the gauge strain in tensile tests.The test system for measuring 3D strain distribution consists of two cameras, a laser, a universal testing machine, an acrylic chamber with a glycerol water solution for adjusting the refractive index with the silicone, and dumbbell-shaped specimens mixed with fluorescent tracer particles. 3D images of the particles were reconstructed from 2D images using a multiplicative algebraic reconstruction technique (MART and motion tracking enhancement. Distributions of the 3D displacements were calculated using a digital volume correlation. To evaluate the accuracy of the measurement method in terms of particle density and interrogation voxel size, the gauge strain and one of the two cameras for Tomo-PIV were used as a video-extensometer in the tensile test. The results show that the optimal particle density and interrogation voxel size are 0.014 particles per pixel and 40 × 40 × 40 voxels with a 75% overlap. The maximum measurement error was maintained at less than 2.5% in the 4-mm-wide region of the specimen.We successfully developed a method to experimentally measure 3D strain distribution in an elastic silicone material using Tomo-PIV and fluorescent particles. To the best of our knowledge, this is the first report that applies Tomo-PIV to investigate 3D strain measurements in elastic materials with large deformation and validates the measurement accuracy.
Karimi, Alireza; Navidbakhsh, Mahdi; Alizadeh, Mansour; Razaghi, Reza
2014-10-01
There have been different stress-strain definitions to measure the elastic modulus of spongy materials, especially polyvinyl alcohol (PVA) sponge. However, there is no agreement as to which stress-strain definition should be implemented. This study was aimed to show how different results are given by the various definitions of stress-strain used, and to recommend a specific definition when testing spongy materials. A fabricated PVA sponge was subjected to a series of tensile tests in order to measure its mechanical properties. Three stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress) and four strain definitions (Almansi-Hamel strain, Green-St. Venant strain, engineering strain, and true strain) were used to determine the elastic modulus. The results revealed that the Almansi-Hamel strain definition exhibited the highest non-linear stress-strain relation and, as a result, may overestimate the elastic modulus at different stress definitions (second Piola-Kichhoff stress, engineering stress, and true stress). The Green-St. Venant strain definition failed to address the non-linear stress-strain relation using different definitions of stress and invoked an underestimation of the elastic modulus values. Engineering stress and strain definitions were only valid for small strains and displacements, which make them impractical when analyzing spongy materials. The results showed that the effect of varying the stress definition on the maximum stress measurements was significant but not when calculating the elastic modulus. It is important to consider which stress-strain definition is employed when characterizing the mechanical properties of spongy materials. Although the true stress-true strain definition exhibits a non-linear relation, we favor it in spongy materials mechanics as it gives more accurate measurements of the material's response using the instantaneous values.
Hybrid Simulation Modeling to Estimate U.S. Energy Elasticities
Baylin-Stern, Adam C.
This paper demonstrates how an U.S. application of CIMS, a technologically explicit and behaviourally realistic energy-economy simulation model which includes macro-economic feedbacks, can be used to derive estimates of elasticity of substitution (ESUB) and autonomous energy efficiency index (AEEI) parameters. The ability of economies to reduce greenhouse gas emissions depends on the potential for households and industry to decrease overall energy usage, and move from higher to lower emissions fuels. Energy economists commonly refer to ESUB estimates to understand the degree of responsiveness of various sectors of an economy, and use estimates to inform computable general equilibrium models used to study climate policies. Using CIMS, I have generated a set of future, 'pseudo-data' based on a series of simulations in which I vary energy and capital input prices over a wide range. I then used this data set to estimate the parameters for transcendental logarithmic production functions using regression techniques. From the production function parameter estimates, I calculated an array of elasticity of substitution values between input pairs. Additionally, this paper demonstrates how CIMS can be used to calculate price-independent changes in energy-efficiency in the form of the AEEI, by comparing energy consumption between technologically frozen and 'business as usual' simulations. The paper concludes with some ideas for model and methodological improvement, and how these might figure into future work in the estimation of ESUBs from CIMS. Keywords: Elasticity of substitution; hybrid energy-economy model; translog; autonomous energy efficiency index; rebound effect; fuel switching.
Elastic scattering and total cross section at very high energies
International Nuclear Information System (INIS)
Castaldi, R.; Sanguinetti, G.
1985-01-01
The aim of this review is to summarize the recent progress in the field of elastic scattering and total cross section in this new energy domain. In Section 2 a survey of the experimental situation is outlined. The most significant data are presented, with emphasis on the interpretation, not the specific details or technicalities. This section is therefore intended to give a self-contained look at the field, especially for the nonspecialist. In Section 3, hadron scattering at high energy is described in an impact parameter picture, which provides a model-independent intuitive geometrical representation. The diffractive character of elastic scattering, seen as the shadow of inelastic absorption, is presented as a consequence of unitarity in the s-channel. Spins are neglected throughout this review, inasmuch as the asymptotic behavior in the very high-energy limit is the main concern here. In Section 4 some relevant theorems are recalled on the limiting behavior of hadron-scattering amplitudes at infinite energy. There is also a brief discussion on how asymptotically rising total cross sections imply scaling properties in the elastic differential cross sections. A quick survey of eikonal models is presented and their predictions are compared with ISR and SPS Collider data
Integrated analysis of energy transfers in elastic-wave turbulence.
Yokoyama, Naoto; Takaoka, Masanori
2017-08-01
In elastic-wave turbulence, strong turbulence appears in small wave numbers while weak turbulence does in large wave numbers. Energy transfers in the coexistence of these turbulent states are numerically investigated in both the Fourier space and the real space. An analytical expression of a detailed energy balance reveals from which mode to which mode energy is transferred in the triad interaction. Stretching energy excited by external force is transferred nonlocally and intermittently to large wave numbers as the kinetic energy in the strong turbulence. In the weak turbulence, the resonant interactions according to the weak turbulence theory produce cascading net energy transfer to large wave numbers. Because the system's nonlinearity shows strong temporal intermittency, the energy transfers are investigated at active and moderate phases separately. The nonlocal interactions in the Fourier space are characterized by the intermittent bundles of fibrous structures in the real space.
Proton-4He elastic scattering at intermediate energies
International Nuclear Information System (INIS)
Auger, J.P.; Gillespie, J.; Lombard, R.J.
1975-12-01
Differential elastic cross sections and polarizations are calculated in a multiple scattering formalism for proton- 4 He scattering for energies in the range 0.6-24GeV and for momentum transfers up to 4.0fmsup(-1). The calculations include Coulomb and spin effects. Corrections due to target-nucleon overlap and charge exchange are estimated. The results are compared with experimental data [fr
Elastic scattering of low energy electrons by hydrogen molecule
International Nuclear Information System (INIS)
Freitas, L.C.G.; Mu-Tao, L.; Botelho, L.F.
1987-01-01
The coherent version of the Renormalized Multiple-Centre Potential Model (RMPM) has been extended to treat the elastic scattering of low energy electrons by H2 molecule. The intramolecular Multiple Scattering (MS) effect has also been included. The comparison against the experimental data shows that the inclusion of the MS improves significantly with experiment. The extension of the present method to study electron-polyatomic molecule interaction is also discussed. (author) [pt
Modelling energy and non-energy substitution: A brief survey of elasticities
International Nuclear Information System (INIS)
Frondel, Manuel
2011-01-01
Estimating the degree of substitution between energy and non-energy inputs is the key for any evaluation of environmental and energy policies. Yet, given the variety of substitution elasticities, the central question arises as to which measure would be most appropriate. Apparently, Allen's elasticities of substitution have been the most-used measures in applied production analysis. In line with , this paper argues that cross-price elasticities are preferable for many practical purposes. This conclusion is based on a survey of classical substitution measures, such as those from Allen, Morishima, and McFadden. The survey highlights the fact that cross-price elasticities are their essential ingredients. - Highlights: → Given the large variety of substitution elasticities, the central question arises as to which measure would be most appropriate. Apparently, Allen's elasticities of substitution have been the most-used measures in applied production analysis. → In line with , this paper argues that cross-price elasticities are preferable for many practical purposes. → This conclusion is based on a survey of classical substitution measures, such as those from Allen, Morishima, and McFadden. → The survey also highlights the fact that cross-price elasticities are their essential ingredients.
In-situ measurement of texture and elastic strains with HIPPO-CRATES
International Nuclear Information System (INIS)
Hartig, Ch.; Vogel, S.C.; Mecking, H.
2006-01-01
In this paper, the micromechanical interaction between constituents of a metallic material during elastic and plastic deformation are analyzed by comparing experimental results with modeling predictions. This comparison aims at determining the locally acting internal stresses, the spatial distribution of strains and the rules allowing deriving the macroscopic behavior of the material from the behavior of its microscopic constituents. We report the application of a new deformation apparatus CRATES, which allows measuring texture and crystal lattice spacings, and from these crystal lattice strains, using neutron diffraction. From the in-situ measured elastic lattice strains ε hkl the corresponding local stresses can be derived. The deformation apparatus allows uni-axial tensile or compressive deformation up to 100 kN and is specifically designed for use in the HIPPO neutron time-of-flight diffractometer. In this paper, we report initial results on an iron-copper model system (Fe100, Fe33Cu67, Fe67Cu33, vol.%) and commercial magnesium alloys (Mg-AZ31 and Mg-AZ80). Finite element calculations using a crystal-plastic constitutive law, allowing for shear and hardening of crystallographic slip-systems, were used for the interpretation of the measurements
A phase field study of strain energy effects on solute–grain boundary interactions
International Nuclear Information System (INIS)
Heo, Tae Wook; Bhattacharyya, Saswata; Chen Longqing
2011-01-01
We have studied strain-induced solute segregation at a grain boundary and the solute drag effect on boundary migration using a phase field model integrating grain boundary segregation and grain structure evolution. The elastic strain energy of a solid solution due to the atomic size mismatch and the coherency elastic strain energy caused by the inhomogeneity of the composition distribution are obtained using Khachaturyan’s microelasticity theory. Strain-induced grain boundary segregation at a static planar boundary is studied numerically and the equilibrium segregation composition profiles are validated using analytical solutions. We then systematically studied the effect of misfit strain on grain boundary migration with solute drag. Our theoretical analysis based on Cahn’s analytical theory shows that enhancement of the drag force with increasing atomic size mismatch stems from both an increase in grain boundary segregation due to the strain energy reduction and misfit strain relaxation near the grain boundary. The results were analyzed based on a theoretical analysis in terms of elastic and chemical drag forces. The optimum condition for solute diffusivity to maximize the drag force under a given driving force was identified.
Energy based methods for determining elastic plastic fracture
International Nuclear Information System (INIS)
Witt, F.J.
1979-01-01
Several methods are currently in use or under study for calculating various conditions of fracturing for varying degrees of plasticity. Among these are innovations on the J-integral concept, crack opening displacement or angle, the two parameter concept and the equivalent energy method. Methods involving crack arrest and ductile tearing also fall in this category. Each of these methods have many salient points and some efforts are underway to establish the underlying relationship between them. In this paper, the current research directions of J-integral and equivalent energy methodologies are reviewed with a broader discussion presented for the equivalent energy methodology. The fundamental basis of equivalent energy methodology rests with the volumetric energy ratio. For fractures governed by linear elastic fracture mechanics, the volumetric energy ratio is independent of flaw size and geometry and depends only on the scale factor between model and prototype and temperature. The behavioral aspects of the volumetric energy ratios have been investigated throughout the temperature range from brittle fracture to fully ductile fracture. For five different specimen and structural configurations it has been shown experimentally that the volumetric energy ratio retains its basic properties. That is, the volumetric energy ratio while changing in actual value, maintains its independence of geometry and flaw size while retaining a unique dependence on scale factor and temperature. This property interpreted in terms of fracture mechanics leads to the equivalent energy method. (orig.)
On higher-order boundary conditions at elastic-plastic boundaries in strain-gradient plasticity
DEFF Research Database (Denmark)
Niordson, Christian Frithiof
2008-01-01
are suppressed by using a very high artificial hardening modulus. Through numerical studies of pure bending under plane strain conditions, it is shown that this method predicts the build-up of higher order stresses in the pseudo-elastic regime. This has the effect of delaying the onset of incipient yield......, as well as extending the plastic zone further toward the neutral axis of the beam, when compared to conventional models. Arguments supporting the present method are presented that rest on both mathematical and physical grounds. The results obtained are compared with other methods for dealing with higher...
International Nuclear Information System (INIS)
Bellucci, H.J.
1975-11-01
The report describes the continuation of research into capability for three-dimensional elastic-plastic stress and strain analysis for fracture mechanics. A computer program, MARC-3D, has been completed and was used to analyze a cylindrical pressure vessel with a nozzle insert. A method for generating crack tip elements was developed and a model was created for a cylindrical pressure vessel with a nozzle and an imbedded flaw at the inside nozzle corner. The MARC-3D program was again used to analyze this flawed model. Documentation for the use of the MARC-3D computer program has been included as an appendix
Material selection for elastic energy absorption in origami-inspired compliant corrugations
International Nuclear Information System (INIS)
Tolman, Sean S; Delimont, Isaac L; Howell, Larry L; Fullwood, David T
2014-01-01
Elastic absorption of kinetic energy and distribution of impact forces are required in many applications. Recent attention to the potential for using origami in engineering may provide new methods for energy absorption and force distribution. A three-stage strategy is presented for selecting materials for such origami-inspired designs that can deform to achieve a desired motion without yielding, absorb elastic strain energy, and be lightweight or cost effective. Two material indices are derived to meet these requirements based on compliant mechanism theory. Finite element analysis is used to investigate the effects of the material stiffness in the Miura-ori tessellation on its energy absorption and force distribution characteristics compared with a triangular wave corrugation. An example is presented of how the method can be used to select a material for a general energy absorption application of the Miura-ori. Whereas the focus of this study is the Miura-ori tessellation, the methods developed can be applied to other tessellated patterns used in energy absorbing or force distribution applications. (paper)
Grain-resolved elastic strains in deformed copper measured by three-dimensional X-ray diffraction
DEFF Research Database (Denmark)
Oddershede, Jette; Schmidt, Søren; Poulsen, Henning Friis
2011-01-01
This X-ray diffraction study reports the grain-resolved elastic strains in about 1000 randomly oriented grains embedded in a polycrystalline copper sample. Diffraction data were collected in situ in the undeformed state and at a plastic strain of 1.5% while the sample was under tensile load...
Frictional and elastic energy in gecko adhesive detachment.
Gravish, Nick; Wilkinson, Matt; Autumn, Kellar
2008-03-06
Geckos use millions of adhesive setae on their toes to climb vertical surfaces at speeds of over 1 m s(-1). Climbing presents a significant challenge for an adhesive since it requires both strong attachment and easy, rapid removal. Conventional pressure-sensitive adhesives are either strong and difficult to remove (e.g. duct tape) or weak and easy to remove (e.g. sticky notes). We discovered that the energy required to detach adhering tokay gecko setae (W(d)) is modulated by the angle (theta) of a linear path of detachment. Gecko setae resist detachment when dragged towards the animal during detachment (theta = 30 degrees ) requiring W(d) = 5.0+/-0.86(s.e.) J m(-2) to detach, largely due to frictional losses. This external frictional loss is analogous to viscous internal frictional losses during detachment of pressure-sensitive adhesives. We found that, remarkably, setae possess a built-in release mechanism. Setae acted as springs when loaded in tension during attachment and returned elastic energy when detached along the optimal path (theta=130 degrees ), resulting in W(d) = -0.8+/-0.12 J m(-2). The release of elastic energy from the setal shaft probably causes spontaneous release, suggesting that curved shafts may enable easy detachment in natural, and synthetic, gecko adhesives.
DEFF Research Database (Denmark)
Jakobsen, Bo; Poulsen, Henning Friis; Lienert, U.
2007-01-01
A novel synchrotron-based technique "high angular resolution 3DXRD" is presented in detail, and applied to the characterization of oxygen-free, high-conductivity copper at a tensile deformation of 2%. The position and shape in reciprocal space of 14 peaks originating from deeply embedded individual...... subgrains is reported. From this dataset the density of redundant dislocations in the individual subgrains is inferred to be below 12 × 1012 m-2 on average. It is found that the subgrains on average experience a reduction in strain of 0.9 × 10-4 with respect to the mean elastic strain of the full grain...
Standard test method for linear-elastic plane-strain fracture toughness KIc of metallic materials
American Society for Testing and Materials. Philadelphia
2009-01-01
1.1 This test method covers the determination of fracture toughness (KIc) of metallic materials under predominantly linear-elastic, plane-strain conditions using fatigue precracked specimens having a thickness of 1.6 mm (0.063 in.) or greater subjected to slowly, or in special (elective) cases rapidly, increasing crack-displacement force. Details of test apparatus, specimen configuration, and experimental procedure are given in the Annexes. Note 1—Plane-strain fracture toughness tests of thinner materials that are sufficiently brittle (see 7.1) can be made using other types of specimens (1). There is no standard test method for such thin materials. 1.2 This test method is divided into two parts. The first part gives general recommendations and requirements for KIc testing. The second part consists of Annexes that give specific information on displacement gage and loading fixture design, special requirements for individual specimen configurations, and detailed procedures for fatigue precracking. Additional a...
Comparison of experiment and theory for elastic-plastic plane strain crack growth
International Nuclear Information System (INIS)
Hermann, L.; Rice, J.R.
1980-02-01
Recent theoretical results on elastic-plastic plane strain crack growth, and experimental results for crack growth in a 4140 steel in terms of the theoretical concepts are reviewed. The theory is based on a recent asymptotic analysis of crack surface opening and strain distributions at a quasi-statically advancing crack tip in an ideally-plastic solid. The analysis is incomplete in that some of the parameters which appear in it are known only approximately, especially at large scale yielding. Nevertheless, it suffices to derive a relation between the imposed loading and amount of crack growth, prior to general yielding, based on the assumption that a geometrically similar near-tip crack profile is maintained during growth. The resulting predictions for the variation of J with crack growth are found to fit well to the experimental results obtained on deeply cracked compact specimens
In-plane anisotropic strain of elastically and plastically deformed III-nitrides on lithium gallate
International Nuclear Information System (INIS)
Namkoong, Gon; Huang, Sa; Moseley, Michael; Doolittle, W. Alan
2009-01-01
We have investigated both elastically and plastically deformed GaN films on lithium gallate, LiGaO 2 , by molecular beam epitaxy. The in-plane lattice parameters were determined from high resolution X-ray diffraction and indicated two different groups of in-plane lattice parameters, influenced by the a- and b-axis of LiGaO 2 . The measured in-plane lattice parameters indicate that there exist both compressive and tensile strains of in-plane GaN along the a- and b-axis of LiGaO 2 , respectively. This anisotropic strain in GaN films forms a slight distortion of the basal-plane hexagonal structure of GaN films, leading to a different critical thickness of 4.0 ± 0.17 and 7.8 ± 0.7 nm along the a- and b-axis of LiGaO 2 , respectively.
Spin asymmetries for elastic scattering in krypton at intermediate energies
International Nuclear Information System (INIS)
Went, M R; McEachran, R P; Lohmann, Birgit; MacGillivray, W R
2002-01-01
Measurements of the spin asymmetry for elastic scattering of spin-polarized electrons from krypton are presented, for incident energies in the range 20-200 eV. The measured spin asymmetries are generally small, and do not exceed 0.25 in magnitude at any energy or angle. The experimental results are compared with calculated values of the Sherman function, obtained by solution of the Dirac-Fock equations. The calculations have been performed with the inclusion of polarization and dynamic distortion potentials, and with the addition of an absorption potential to model inelastic processes. For incident energies of 50, 60 and 65 eV, the calculated values of the Sherman function are shown to be extremely sensitive to the details of the model, with the addition of the absorption potential producing dramatically different results
Elastic scattering of low-energy electrons with Sr atoms
International Nuclear Information System (INIS)
Yuan, J.; Zhang, Z.; Wan, H.
1990-01-01
Static-exchange, plus correlation-polarization-potential calculations are performed for elastic low-energy electron scattering from Sr atoms while paying attention to the low-lying shape resonances. The correlation potential is calculated both with and without a scaling factor. A 2 D-shape resonance is produced at 1.0 eV with a parameter-free, and at 1.25 eV with a scaled, correlation potential. No 2 P-shape resonances are predicted, but evidence to support the existence of a stable negative ion Sr - in the 5s 2 5p electron configuration is given from the viewpoint of electron scattering. The bound energy of the extra electron in the negative ion is estimated by transforming the phase shift of the corresponding partial wave into the polarization quantum-defect number and extrapolating the number from positive to negative energies
np elastic scattering analyzing power characteristics at intermediate energies
International Nuclear Information System (INIS)
Abegg, R.; Davis, C.A.; Delheij, P.P.J.; Green, P.W.; Greeniaus, L.G.; Healey, D.C.; Miller, C.A.; Rodning, N.L.; Wait, G.D.; Ahmad, M.; Cairns, E.B.; Coombes, G.H.; Lapointe, C.; McDonald, W.J.; Moss, G.A.; Roy, G.; Soukup, J.; Tkachuk, R.R.; Ye, Y.; Watson, J.W.
1989-06-01
Recent measurements of charge symmetry breaking in the np system at 477 MeV, and of A oonn for np elastic scattering at 220, 325 and 425 MeV also yield accurate analyzing power data. These data allow the energy dependence of the analyzing power zero-crossing angle and the slope of the analyzing power at the zero-crossing to be determined. The incident neutron energies span a region where the zero-crossing angle is strongly energy dependent (Ε n n > 350 MeV). The results are compared to current phase shift analysis predictions, recently published LAMPF data, and the predictions of the Bonn and Paris potentials. (Author) 13 refs., 2 tabs., 2 figs
Dynamics of pre-strained bi-material elastic systems linearized three-dimensional approach
Akbarov, Surkay D
2015-01-01
This book deals with dynamics of pre-stressed or pre-strained bi-material elastic systems consisting of stack of pre-stressed layers, stack of pre-stressed layers and pre-stressed half space (or half plane), stack of pre-stressed layers as well as absolute rigid foundation, pre-stressed compound solid and hollow cylinders and pre-stressed sandwich hollow cylinders. The problems considered in the book relate to the dynamics of a moving and oscillating moving load, forced vibration caused by linearly located or point located time-harmonic forces acting to the foregoing systems. Moreover, a considerable part of the book relate to the problems regarding the near surface, torsional and axisymmetric longitudinal waves propagation and dispersion in the noted above bi-material elastic systems. The book carries out the investigations within the framework of the piecewise homogeneous body model with the use of the Three-Dimensional Linearized Theory of Elastic Waves in Initially Stressed Bodies.
US energy product supply elasticities. A survey and application to the US oil market
International Nuclear Information System (INIS)
Dahl, Carol; Duggan, Thomas E.
1996-01-01
We survey studies of simple energy supply models to find the most promising technique for developing supply elasticities in the U.S. crude oil market. The two dozen studies located include direct estimates of energy supply elasticities or cost studies from which supply or reserve elasticities can be inferred. We include all available studies for all forms of energy both primary and secondary. We find direct estimates of oil supply to obtain weak results unless depletion and price expectations are included. Oil product supply elasticities vary widely across studies but appear to be elastic. Studies that estimate reserve price elasticities by computing reserve costs appear to be the most promising for estimating reserve elasticities for fossil fuel supply. Hence we apply this technique to US oil reserves and find a reserve elasticity of 1.27
International Nuclear Information System (INIS)
Welch, D.O.
1979-01-01
Elastic strains alter (usually, but not always, adversely) the critical temperatures, magnetic fields, and current densities of superconducting A15 compounds; non-hydrostatic strain states are particularly effective in this regard. This paper is a review of the experimental evidence, obtained by a variety of techniques, concerning the strain dependence of the critical properties of a number of A15 compounds and a discussion of theoretical models for describing such effects
Skin-like pressure and strain sensors based on transparent elastic films of carbon nanotubes.
Lipomi, Darren J; Vosgueritchian, Michael; Tee, Benjamin C-K; Hellstrom, Sondra L; Lee, Jennifer A; Fox, Courtney H; Bao, Zhenan
2011-10-23
Transparent, elastic conductors are essential components of electronic and optoelectronic devices that facilitate human interaction and biofeedback, such as interactive electronics, implantable medical devices and robotic systems with human-like sensing capabilities. The availability of conducting thin films with these properties could lead to the development of skin-like sensors that stretch reversibly, sense pressure (not just touch), bend into hairpin turns, integrate with collapsible, stretchable and mechanically robust displays and solar cells, and also wrap around non-planar and biological surfaces such as skin and organs, without wrinkling. We report transparent, conducting spray-deposited films of single-walled carbon nanotubes that can be rendered stretchable by applying strain along each axis, and then releasing this strain. This process produces spring-like structures in the nanotubes that accommodate strains of up to 150% and demonstrate conductivities as high as 2,200 S cm(-1) in the stretched state. We also use the nanotube films as electrodes in arrays of transparent, stretchable capacitors, which behave as pressure and strain sensors.
Effect of plastic deformation and strain history on X-ray elastic constants
International Nuclear Information System (INIS)
Iadicola, Mark A.; Foecke, Tim
2005-01-01
The use of X-ray diffraction to measure residual stress in a crystalline material is well known. This method is currently being reapplied to the surface measurement of in situ stresses during biaxial straining of sheet metal specimens. This leads to questions of precision and calibration of the method through plastic deformation. Little is known of the change, with plastic work, in the X-ray elastic constants (XECs) that are required by the technique for stress measurement. Experiments to determine the formability of various materials using this stress measurement technique in conjunction with a typical Marciniak test (with the Raghavan variation of specimen shapes) have been performed assuming a constant value for XECs. New results of calibration experiments are presented which admit the possibility of variation of the XECs with plastic strain history and initial texture of the material. Adjustment of the data from the previously performed formability experiments is shown. Additionally, various phenomena are captured including initial yielding, change of XECs with plastic strain level (both with uniaxial and biaxial strain histories), and some of the effects of texture on the technique. This technique has potential application in verification of the assumptions made during other standard testing methods (in-plane biaxial specimen geometries and bulge testing), verifying stress predictions from finite element analyses (i.e. benchmarking experiments such as BM3), analysis of stress states in localized deformation (yield point effects), and tracking of the effect of prestraining on material formability through the process of multistage forming
Nonperturbative QCD and elastic processes at CEBAF energies
Energy Technology Data Exchange (ETDEWEB)
Radyushkin, A.V. [Old Dominion Univ., Norfolk, VA (United States)]|[Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)
1994-04-01
The author outlines how one can approach nonperturbative aspects of the QCD dynamics studying elastic processes at energies accessible at upgraded CEBAF. The author`s point is that, in the absence of a complete theory of the nonperturbative effects, a possible way out is based on a systematic use of the QCD factorization procedure which separates theoretically understood ({open_quotes}known{close_quotes}) short-distance effects and nonperturbative ({open_quotes}unknown{close_quotes}) long-distance ones. The latter include hadronic distribution amplitudes, soft components of hadronic form factors etc. Incorporating the QCD sum rule version of the QCD factorization approach, one can relate these nonperturbative functions to more fundamental objects, vacuum condensates, which accumulate information about the nonperturbative structure of the QCD vacuum. The emerging QCD sum rule picture of hadronic form factors is characterized by a dominant role of essentially nonperturbative effects in the few GeV region, with perturbative mechanisms starting to show up for momentum transfers Q{sup 2} closer to 10 GeV{sup 2} and higher. Thus, increasing CEBAF energy provides a unique opportunity for a precision study of interplay between the perturbative and nonperturbative phenomena in the QCD description of elastic processes.
Nonperturbative QCD and elastic processes at CEBAF energies
International Nuclear Information System (INIS)
Radyushkin, A.V.
1994-01-01
The author outlines how one can approach nonperturbative aspects of the QCD dynamics studying elastic processes at energies accessible at upgraded CEBAF. The author's point is that, in the absence of a complete theory of the nonperturbative effects, a possible way out is based on a systematic use of the QCD factorization procedure which separates theoretically understood (open-quotes knownclose quotes) short-distance effects and nonperturbative (open-quotes unknownclose quotes) long-distance ones. The latter include hadronic distribution amplitudes, soft components of hadronic form factors etc. Incorporating the QCD sum rule version of the QCD factorization approach, one can relate these nonperturbative functions to more fundamental objects, vacuum condensates, which accumulate information about the nonperturbative structure of the QCD vacuum. The emerging QCD sum rule picture of hadronic form factors is characterized by a dominant role of essentially nonperturbative effects in the few GeV region, with perturbative mechanisms starting to show up for momentum transfers Q 2 closer to 10 GeV 2 and higher. Thus, increasing CEBAF energy provides a unique opportunity for a precision study of interplay between the perturbative and nonperturbative phenomena in the QCD description of elastic processes
Liu, Yan-Jun; Cao, Wen-Tao; Ma, Ming-Guo; Wan, Pengbo
2017-08-02
Robust, stretchable, and strain-sensitive hydrogels have recently attracted immense research interest because of their potential application in wearable strain sensors. The integration of the synergistic characteristics of decent mechanical properties, reliable self-healing capability, and high sensing sensitivity for fabricating conductive, elastic, self-healing, and strain-sensitive hydrogels is still a great challenge. Inspired by the mechanically excellent and self-healing biological soft tissues with hierarchical network structures, herein, functional network hydrogels are fabricated by the interconnection between a "soft" homogeneous polymer network and a "hard" dynamic ferric (Fe 3+ ) cross-linked cellulose nanocrystals (CNCs-Fe 3+ ) network. Under stress, the dynamic CNCs-Fe 3+ coordination bonds act as sacrificial bonds to efficiently dissipate energy, while the homogeneous polymer network leads to a smooth stress-transfer, which enables the hydrogels to achieve unusual mechanical properties, such as excellent mechanical strength, robust toughness, and stretchability, as well as good self-recovery property. The hydrogels demonstrate autonomously self-healing capability in only 5 min without the need of any stimuli or healing agents, ascribing to the reorganization of CNCs and Fe 3+ via ionic coordination. Furthermore, the resulted hydrogels display tunable electromechanical behavior with sensitive, stable, and repeatable variations in resistance upon mechanical deformations. Based on the tunable electromechanical behavior, the hydrogels can act as a wearable strain sensor to monitor finger joint motions, breathing, and even the slight blood pulse. This strategy of building synergistic "soft and hard" structures is successful to integrate the decent mechanical properties, reliable self-healing capability, and high sensing sensitivity together for assembling a high-performance, flexible, and wearable strain sensor.
Elastic scattering of low energy γ-rays
International Nuclear Information System (INIS)
Whittingham, I.B.
1978-05-01
Theoretical cross sections for the elastic scattering of 245, 334, 444, 779, 1086, 1112 and 1408 keV γ-rays by Pb are obtained for scattering angles up to 150 degrees. Three sets of Rayleigh scattering amplitudes have been computed using (1) the calculations of Johnson and Cheng, (2) the K shell calculations of Brown and co-workers supplemented by form factors amplitudes for higher shells, and (3) form factor amplitudes for all shells. Nuclear Thomson amplitudes have been included for all energies and, for 1408 keV, Delbruck scattering based upon the calculations of Papatzacos and Mork has been included. Nuclear resonance scattering is show to be negligble for all energies
Elastic energy of liquid crystals in convex polyhedra
International Nuclear Information System (INIS)
Majumdar, A; Robbins, J M; Zyskin, M
2004-01-01
We consider nematic liquid crystals in a bounded, convex polyhedron described by a director field n(r) subject to tangent boundary conditions. We derive lower bounds for the one-constant elastic energy in terms of topological invariants. For a right rectangular prism and a large class of topologies, we derive upper bounds by introducing test configurations constructed from local conformal solutions of the Euler-Lagrange equation. The ratio of the upper and lower bounds depends only on the aspect ratios of the prism. As the aspect ratios are varied, the minimum-energy conformal state undergoes a sharp transition from being smooth to having singularities on the edges. (letter to the editor)
Konow, Nicolai; Roberts, Thomas J
2015-04-07
During downhill running, manoeuvring, negotiation of obstacles and landings from a jump, mechanical energy is dissipated via active lengthening of limb muscles. Tendon compliance provides a 'shock-absorber' mechanism that rapidly absorbs mechanical energy and releases it more slowly as the recoil of the tendon does work to stretch muscle fascicles. By lowering the rate of muscular energy dissipation, tendon compliance likely reduces the risk of muscle injury that can result from rapid and forceful muscle lengthening. Here, we examine how muscle-tendon mechanics are modulated in response to changes in demand for energy dissipation. We measured lateral gastrocnemius (LG) muscle activity, force and fascicle length, as well as leg joint kinematics and ground-reaction force, as turkeys performed drop-landings from three heights (0.5-1.5 m centre-of-mass elevation). Negative work by the LG muscle-tendon unit during landing increased with drop height, mainly owing to greater muscle recruitment and force as drop height increased. Although muscle strain did not increase with landing height, ankle flexion increased owing to increased tendon strain at higher muscle forces. Measurements of the length-tension relationship of the muscle indicated that the muscle reached peak force at shorter and likely safer operating lengths as drop height increased. Our results indicate that tendon compliance is important to the modulation of energy dissipation by active muscle with changes in demand and may provide a mechanism for rapid adjustment of function during deceleration tasks of unpredictable intensity. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
Compatible-strain mixed finite element methods for incompressible nonlinear elasticity
Faghih Shojaei, Mostafa; Yavari, Arash
2018-05-01
We introduce a new family of mixed finite elements for incompressible nonlinear elasticity - compatible-strain mixed finite element methods (CSFEMs). Based on a Hu-Washizu-type functional, we write a four-field mixed formulation with the displacement, the displacement gradient, the first Piola-Kirchhoff stress, and a pressure-like field as the four independent unknowns. Using the Hilbert complexes of nonlinear elasticity, which describe the kinematics and the kinetics of motion, we identify the solution spaces of the independent unknown fields. In particular, we define the displacement in H1, the displacement gradient in H (curl), the stress in H (div), and the pressure field in L2. The test spaces of the mixed formulations are chosen to be the same as the corresponding solution spaces. Next, in a conforming setting, we approximate the solution and the test spaces with some piecewise polynomial subspaces of them. Among these approximation spaces are the tensorial analogues of the Nédélec and Raviart-Thomas finite element spaces of vector fields. This approach results in compatible-strain mixed finite element methods that satisfy both the Hadamard compatibility condition and the continuity of traction at the discrete level independently of the refinement level of the mesh. By considering several numerical examples, we demonstrate that CSFEMs have a good performance for bending problems and for bodies with complex geometries. CSFEMs are capable of capturing very large strains and accurately approximating stress and pressure fields. Using CSFEMs, we do not observe any numerical artifacts, e.g., checkerboarding of pressure, hourglass instability, or locking in our numerical examples. Moreover, CSFEMs provide an efficient framework for modeling heterogeneous solids.
Roubíček, Tomáš; Tomassetti, Giuseppe
2018-06-01
A theory of elastic magnets is formulated under possible diffusion and heat flow governed by Fick's and Fourier's laws in the deformed (Eulerian) configuration, respectively. The concepts of nonlocal nonsimple materials and viscous Cahn-Hilliard equations are used. The formulation of the problem uses Lagrangian (reference) configuration while the transport processes are pulled back. Except the static problem, the demagnetizing energy is ignored and only local non-self-penetration is considered. The analysis as far as existence of weak solutions of the (thermo) dynamical problem is performed by a careful regularization and approximation by a Galerkin method, suggesting also a numerical strategy. Either ignoring or combining particular aspects, the model has numerous applications as ferro-to-paramagnetic transformation in elastic ferromagnets, diffusion of solvents in polymers possibly accompanied by magnetic effects (magnetic gels), or metal-hydride phase transformation in some intermetallics under diffusion of hydrogen accompanied possibly by magnetic effects (and in particular ferro-to-antiferromagnetic phase transformation), all in the full thermodynamical context under large strains.
Spacecraft Dynamic Characterization by Strain Energies Method
Bretagne, J.-M.; Fragnito, M.; Massier, S.
2002-01-01
In the last years the significant increase in satellite broadcasting demand, with the wide band communication dawn, has given a great impulse to the telecommunication satellite market. The big demand is translated from operators (such as SES/Astra, Eutelsat, Intelsat, Inmarsat, EuroSkyWay etc.) in an increase of orders of telecom satellite to the world industrials. The largest part of these telecom satellite orders consists of Geostationary platforms which grow more and more in mass (over 5 tons) due to an ever longer demanded lifetime (up to 20 years), and become more complex due to the need of implementing an ever larger number of repeaters, antenna reflectors and feeds, etc... In this frame, the mechanical design and verification of these large spacecraft become difficult and ambitious at the same time, driven by the dry mass limitation objective. By the Finite Element Method (FEM), and on the basis of the telecom satellite heritage of a world leader constructor such as Alcatel Space Industries it is nowadays possible to model these spacecraft in a realistic and confident way in order to identify the main global dynamic aspects such as mode shapes, mass participation and/or dynamic responses. But on the other hand, one of the main aims consists in identifying soon in a program the most critical aspects of the system behavior in the launch dynamic environment, such as possible dynamic coupling between the different subsystems and secondary structures of the spacecraft (large deployable reflectors, thrusters, etc.). To this aim a numerical method has been developed in the frame of the Alcatel SPACEBUS family program, using MSC/Nastran capabilities and it is presented in this paper. The method is based on Spacecraft sub-structuring and strain energy calculation. The method mainly consists of two steps : 1) subsystem modal strain energy ratio (with respect to the global strain energy); 2) subsystem strain energy calculation for each mode according to the base driven
International Nuclear Information System (INIS)
Wesseh, Presley K.; Lin, Boqiang
2016-01-01
This study estimates output and substitution elasticities of renewable energy and nonrenewable energy for the Economic Community of West African States (ECOWAS) and discusses implications for expanding the former. The results show that nonrenewable energy promises greater benefits for ECOWAS economic transition, with output elasticities averaging between 0.052–0.579 and −0.055 to 0.223 for nonrenewable energy and renewable energy respectively. Overall estimated technological progress is low (−0.5% to 2.6%); the bulk coming from input efficiency. Substitution elasticities (0.02–0.94) suggest potential for switching towards renewable energy. Notwithstanding, scale, economics and sitting problems inherent in renewable power generation challenge the opportunities for energy substitution. A sustainable policy solution, therefore, appears to be one favoring scaled and efficient electricity generation from fossil energy in the short-run with a gradual switch towards renewable power in the long-run. In general, the applied model provides insights that energy efficiency enhances sustainable growth by propelling technological advancement especially when technical change is scale-biased and factor-augmenting. The study also provides insights that impacts of exogenous shocks to inputs are temporary, and hence, do not jeopardize efforts aimed at scaling output through increased and efficient use of labor, capital and energy; especially nonrenewable energy. - Highlights: • Output and substitution elasticities of energy are estimated for the ECOWAS region. • Nonrenewable energy promises greater opportunities for economic growth. • Technical progress is low and driven mainly by the efficiency of inputs. • Energy efficiency drives technological innovation. • Potential of switching towards renewable energy is high but suffers feasibility gaps.
Directory of Open Access Journals (Sweden)
Tien-Wei Shyr
2011-01-01
Full Text Available To use e-textiles as a strain-resistance sensor they need to be both elastic and conductive. Three kinds of elastic-conductive webbings, including flat, tubular, and belt webbings, made of Lycra fiber and carbon coated polyamide fiber, were used in this study. The strain-resistance properties of the webbings were evaluated in stretch-recovery tests and measured within 30% strain. It was found that tensile hysteresis and contact resistance significantly influence the tensile elasticity and the resistance sensitivity of the webbings. The results showed that the webbing structure definitely contributes to the tensile hysteresis and contact resistance. The smaller the friction is among the yarns in the belt webbing, the smaller the tensile hysteresis loss. However the close proximity of the conductive yarns in flat and tubular webbings results in a lower contact resistance.
Energy Technology Data Exchange (ETDEWEB)
Levine, Lyle E. [National Institute of Standards and Technology (NIST); Larson, Ben C [ORNL; Yang, Wenge [Carnegie Institution of Washington; Kassner, Michael E. [University of Southern California; Tischler, Jonathan Zachary [ORNL; Delos-Reyes, Michael A. [University of Southern California; Fields, Richard J. [National Institute of Standards and Technology (NIST); Liu, Wenjun [Argonne National Laboratory (ANL)
2006-01-01
The distribution of elastic strains (and thus stresses) at the sub-micrometer length scale within deformed metal single crystals has surprisingly broad implications for our understanding of important physical phenomena. These include the evolution of the complex dislocation structures that govern mechanical behavior within individual grains [1-4], the transport of dislocations through such structures [5-7], changes in mechanical properties that occur during reverse loading [8-10] (e.g. sheet metal forming), and the analyses of diffraction line profiles for microstructural studies of these phenomena [11-17]. We present the first direct, spatially-resolved measurements of the elastic strains within individual dislocation cells in copper single crystals deformed in tension and compression along <100> axes. Broad distributions of elastic strains are found, with profound implications for theories of dislocation structure evolution [4,18], dislocation transport [5-7], and the extraction of dislocation parameters from X-ray line profiles [11-17,19].
Wager, Justin C; Challis, John H
2016-03-21
During locomotion, the lower limb tendons undergo stretch and recoil, functioning like springs that recycle energy with each step. Cadaveric testing has demonstrated that the arch of the foot operates in this capacity during simple loading, yet it remains unclear whether this function exists during locomotion. In this study, one of the arch׳s passive elastic tissues (the plantar aponeurosis; PA) was investigated to glean insights about it and the entire arch of the foot during running. Subject specific computer models of the foot were driven using the kinematics of eight subjects running at 3.1m/s using two initial contact patterns (rearfoot and non-rearfoot). These models were used to estimate PA strain, force, and elastic energy storage during the stance phase. To examine the release of stored energy, the foot joint moments, powers, and work created by the PA were computed. Mean elastic energy stored in the PA was 3.1±1.6J, which was comparable to in situ testing values. Changes to the initial contact pattern did not change elastic energy storage or late stance PA function, but did alter PA pre-tensioning and function during early stance. In both initial contact patterns conditions, the PA power was positive during late stance, which reveals that the release of the stored elastic energy assists with shortening of the arch during push-off. As the PA is just one of the arch׳s passive elastic tissues, the entire arch may store additional energy and impact the metabolic cost of running. Copyright © 2016 Elsevier Ltd. All rights reserved.
p-barp elastic scattering at high energies
International Nuclear Information System (INIS)
Padua, A.B. de.
1986-01-01
The p-bar p elastic scattering is analysed in the energy range 9.78 pp werefitted under the hypothesis of a pure imaginary amplitude and writted as a sum of exponentials, that is, a(s,t) = a(s,O) Σ n i=l α i exp β i t. Using the parameters a(s,O), α i and β i we obtained the absorption constante K- pp , the form factor and the mean square radius of the - p matter distribution by the Chou-Yang model. These calculations reveal a dip around -t ≅ 1.3 (GeV/c) 2 at 31 and 62 GeV. (author) [pt
Thomas, Alec N; Borden, Mark A
2017-11-28
The microbubble offers a unique platform to study lung surfactant mechanics at physiologically relevant geometry and length scale. In this study, we compared the response of microbubbles (∼15 μm initial radius) coated with pure dipalmitoyl-phosphatidylcholine (DPPC) versus naturally derived lung surfactant (SURVANTA) when subjected to linearly increasing hydrostatic pressure at different rates (0.5-2.3 kPa/s) at room temperature. The microbubbles contained perfluorobutane gas and were submerged in buffered saline saturated with perfluorobutane at atmospheric pressure. Bright-field microscopy showed that DPPC microbubbles compressed spherically and smoothly, whereas SURVANTA microbubbles exhibited wrinkling and smoothing cycles associated with buckling and collapse. Seismograph analysis showed that the SURVANTA collapse amplitude was constant, but the collapse rate increased with the pressurization rate. An analysis of the pressure-volume curves indicated that the dilatational elasticity increased during compression for both shell types. The initial dilatational elasticity for SURVANTA was nearly twice that of DPPC at higher pressurization rates (>1.5 kPa/s), producing a pressure drop of up to 60 kPa across the film prior to condensation of the perfluorobutane core. The strain-rate dependent stiffening of SURVANTA shells likely arises from their composition and microstructure, which provide enhanced in-plane monolayer rigidity and lateral repulsion from surface-associated collapse structures. Overall, these results provide new insights into lung surfactant mechanics and collapse behavior during compression.
Rajagopal, K. R.
2011-01-06
This paper is the first part of an extended program to develop a theory of fracture in the context of strain-limiting theories of elasticity. This program exploits a novel approach to modeling the mechanical response of elastic, that is non-dissipative, materials through implicit constitutive relations. The particular class of models studied here can also be viewed as arising from an explicit theory in which the displacement gradient is specified to be a nonlinear function of stress. This modeling construct generalizes the classical Cauchy and Green theories of elasticity which are included as special cases. It was conjectured that special forms of these implicit theories that limit strains to physically realistic maximum levels even for arbitrarily large stresses would be ideal for modeling fracture by offering a modeling paradigm that avoids the crack-tip strain singularities characteristic of classical fracture theories. The simplest fracture setting in which to explore this conjecture is anti-plane shear. It is demonstrated herein that for a specific choice of strain-limiting elasticity theory, crack-tip strains do indeed remain bounded. Moreover, the theory predicts a bounded stress field in the neighborhood of a crack-tip and a cusp-shaped opening displacement. The results confirm the conjecture that use of a strain limiting explicit theory in which the displacement gradient is given as a function of stress for modeling the bulk constitutive behavior obviates the necessity of introducing ad hoc modeling constructs such as crack-tip cohesive or process zones in order to correct the unphysical stress and strain singularities predicted by classical linear elastic fracture mechanics. © 2011 Springer Science+Business Media B.V.
Wiesinger, Hans-Peter; Rieder, Florian; Kösters, Alexander; Müller, Erich; Seynnes, Olivier R
2017-01-01
Introduction: During running and jumping activities, elastic energy is utilized to enhance muscle mechanical output and efficiency. However, training-induced variations in tendon spring-like properties remain under-investigated. The present work extends earlier findings on sport-specific profiles of tendon stiffness and cross-sectional area to examine whether years of distinct loading patterns are reflected by tendons' ability to store and return energy. Methods: Ultrasound scans were performed to examine the morphological features of knee extensor and plantar flexor muscle-tendon units in elite ski jumpers, distance runners, water polo players, and sedentary controls. Tendon strain energy and hysteresis were measured with combined motion capture, ultrasonography, and dynamometry. Results: Apart from the fractional muscle-to-tendon cross-sectional area ratio being lower in the knee extensors of ski jumpers (-31%) and runners (-33%) than in water polo players, no difference in the considered muscle-tendon unit morphological features was observed between groups. Similarly, no significant difference in tendon energy storage or energy return was detected between groups. In contrast, hysteresis was lower in the patellar tendon of ski jumpers (-33%) and runners (-30%) compared to controls, with a similar trend for the Achilles tendon (significant interaction effect and large effect sizes η 2 = 0.2). Normalized to body mass, the recovered strain energy of the patellar tendon was ~50% higher in ski jumpers than in water polo players and controls. For the Achilles tendon, recovered strain energy was ~40% higher in ski jumpers and runners than in controls. Discussion: Advantageous mechanical properties related to tendon spring-like function are observed in elite athletes whose sport require effective utilization of elastic energy. However, the mechanisms underpinning the better tendon capacity of some athletes to retain elastic energy could not be ascribed to intrinsic or
8B + 208Pb Elastic Scattering at Coulomb Barrier Energies
La Commara, M.; Mazzocco, M.; Boiano, A.; Boiano, C.; Manea, C.; Parascandolo, C.; Pierroutsakou, D.; Signorini, C.; Strano, E.; Torresi, D.; Yamaguchi, H.; Kahl, D.; Di Meo, P.; Grebosz, J.; Imai, N.; Hirayama, Y.; Ishiyama, H.; Iwasa, N.; Jeong, S. C.; Jia, H. M.; Kim, Y. H.; Kimura, S.; Kubono, S.; Lin, C. J.; Miyatake, H.; Mukai, M.; Nakao, T.; Nicoletto, M.; Sakaguchi, Y.; Sánchez-Benítez, A. M.; Soramel, F.; Teranishi, T.; Wakabayashi, Y.; Watanabe, Y. X.; Yang, L.; Yang, Y. Y.
2018-02-01
The scattering process of weakly-bound nuclei at Coulomb barrier energies provides deep insights on the reaction dynamics induced by exotic nuclei. Within this framework, we measured for the first time the scattering process of the short-lived Radioactive Ion Beam (RIB) 8B (Sp = 0.1375 MeV) from a 208Pb target at 50 MeV beam energy. The 8B RIB was produced by means of the in-flight facility CRIB (RIKEN, Japan) with an average intensity on target of 10 kHz and a purity about 25%. Elastically scattering ions were detected in the angular range θc.m. = 10°-160° by means of the detector array EXPADES. A preliminary optical model analysis indicates a total reaction cross section of about 1 b, a value, once reduced, 2-3 times larger than those obtained for the reactions induced by the stable weakly-bound projectiles 6,7Li on a 208Pb target in the energy range around the Coulomb barrier.
The influence of elastic strain on the early stages of decomposition in Cu–1.7at% Fe
Rademacher, Thomas
2009-04-01
The initial stage of decomposition of homogenized Cu-1.7 at% Fe at 722 K was investigated by means of field ion microscopy (FIM), atom probe tomography (APT) and computer-assisted field ion image tomography (cFIIT). The agglomeration of atoms depending on time could be investigated and the growth of precipitates with a diameter of few nanometers was observed during ongoing nucleation. For the cFIIT measurements, an improved reconstruction algorithm was developed. Employing cFIIT in combination with FIM images, alignments of precipitates mainly in < 100 > directions were found. Besides, a general experimental concept to evaluate strain-related effects on the position of the proximate precipitate will be introduced. These analyses of the APT and cFIIT data show tendencies of a preferred < 100 > directed configuration as well. This effect can be associated with the elastic anisotropy of the Cu matrix (f.c.c.) to accommodate the volume misfit of precipitates. In accordance with previous model calculations, a preferred nucleation in < 100 > directions with respect to existing clusters can be concluded. For such cluster arrangements strain energy reduction is largest for precipitates adapting their sizes. Thus, additional stabilization against coarsening can be inferred for < 100 > alignments which result in the observed effects. (C) 2008 Published by Elsevier B.V.
Directory of Open Access Journals (Sweden)
Li Ma
2017-04-01
Full Text Available Objective: To study the correlation between the ultrasonic elastic strain ratio of thyroid cancer and the malignant biological characteristics of cancer cells in the lesions. Methods: A total of 90 patients with thyroid cancer who accepted surgical treatment in our hospital between March 2015 and September 2016 were selected as the observation group, and 50 patients who received surgery in our hospital during the same period and were with clear pathological diagnosis of thyroid adenoma were selected as the control group. According to the median of ultrasonic elastic strain ratio, the observing group were further divided into high elastic strain ratio group and low elastic strain ratio group (n=45. RT-PCR was used to determine the mRNA expression of proliferation genes, invasion genes and autophagy genes in lesions of all groups of patients. Results: The mean elastic strain ratio of observation group was significantly lower than that of control group. Proliferation gene FOXA1 mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were higher than those of control group while PP4R1 and Smac mRNA expression were lower than those of control group, and as the elastic strain ratio decreased, the FOXA1 mRNA expression increased while PP4R1 and Smac mRNA expression decreased; invasion genes BCORL1, SATB1, Twist1 and CXCR4 mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were higher than those of control group, and as the elastic strain ratio decreased, the BCORL1, SATB1, Twist1 and CXCR4 mRNA expression increased; autophagy genes ARHI, Beclin1, LC3 and PTEN mRNA expression in lesions of low elastic strain ratio group and high elastic strain ratio group were lower than those of control group, and as the elastic strain ratio decreased, the ARHI, Beclin1, LC3 and PTEN mRNA expression decreased. Conclusion: The ultrasonic elastic strain ratio of thyroid cancer is
In-plane anisotropic strain of elastically and plastically deformed III-nitrides on lithium gallate
Energy Technology Data Exchange (ETDEWEB)
Namkoong, Gon, E-mail: gnamkoon@odu.ed [Old Dominion University, Electrical and Computer Engineering, Applied Research Center, 12050 Jefferson Avenue, Newport News, VA 23606 (United States); Huang, Sa; Moseley, Michael; Doolittle, W. Alan [Georgia Institute of Technology, School of Electrical and Computer Engineering, 777 Atlantic Dr., Atlanta, GA 30332 (United States)
2009-10-30
We have investigated both elastically and plastically deformed GaN films on lithium gallate, LiGaO{sub 2}, by molecular beam epitaxy. The in-plane lattice parameters were determined from high resolution X-ray diffraction and indicated two different groups of in-plane lattice parameters, influenced by the a- and b-axis of LiGaO{sub 2}. The measured in-plane lattice parameters indicate that there exist both compressive and tensile strains of in-plane GaN along the a- and b-axis of LiGaO{sub 2}, respectively. This anisotropic strain in GaN films forms a slight distortion of the basal-plane hexagonal structure of GaN films, leading to a different critical thickness of 4.0 {+-} 0.17 and 7.8 {+-} 0.7 nm along the a- and b-axis of LiGaO{sub 2}, respectively.
Strain tensor selection and the elastic theory of incompatible thin sheets.
Oshri, Oz; Diamant, Haim
2017-05-01
The existing theory of incompatible elastic sheets uses the deviation of the surface metric from a reference metric to define the strain tensor [Efrati et al., J. Mech. Phys. Solids 57, 762 (2009)JMPSA80022-509610.1016/j.jmps.2008.12.004]. For a class of simple axisymmetric problems we examine an alternative formulation, defining the strain based on deviations of distances (rather than distances squared) from their rest values. While the two formulations converge in the limit of small slopes and in the limit of an incompressible sheet, for other cases they are found not to be equivalent. The alternative formulation offers several features which are absent in the existing theory. (a) In the case of planar deformations of flat incompatible sheets, it yields linear, exactly solvable, equations of equilibrium. (b) When reduced to uniaxial (one-dimensional) deformations, it coincides with the theory of extensible elastica; in particular, for a uniaxially bent sheet it yields an unstrained cylindrical configuration. (c) It gives a simple criterion determining whether an isometric immersion of an incompatible sheet is at mechanical equilibrium with respect to normal forces. For a reference metric of constant positive Gaussian curvature, a spherical cap is found to satisfy this criterion except in an arbitrarily narrow boundary layer.
Elastic energy loss and longitudinal straggling of a hard jet
International Nuclear Information System (INIS)
Majumder, A.
2009-01-01
The elastic energy loss encountered by jets produced in deep-inelastic scattering (DIS) off a large nucleus is studied in the collinear limit. In close analogy to the case of (nonradiative) transverse momentum broadening, which is dependent on the medium transport coefficient q, a class of medium enhanced higher twist operators which contribute to the nonradiative loss of the forward light-cone momentum of the jet (q - ) are identified and the leading correction in the limit of asymptotically high q - is isolated. Based on these operator products, a new transport coefficient e is motivated which quantifies the energy loss per unit length encountered by the hard jet. These operator products are then computed, explicitly, in the case of a similar hard jet traversing a deconfined quark-gluon plasma (QGP) in the hard-thermal-loop (HTL) approximation. This is followed by an evaluation of subleading contributions which are suppressed by the inverse light-cone momentum q - , which yields the longitudinal 'straggling', i.e., a slight change in light cone momentum due to the Brownian propagation through a medium with a fluctuating color field.
Armington elasticities for energy policy modeling: Evidence from four European countries
International Nuclear Information System (INIS)
Welsch, Heinz
2008-01-01
Elasticities of substitution among imports and competing domestic production (Armington elasticities) play an important role in computable general equilibrium (CGE) assessments of energy and climate policy. This paper provides estimates of Armington elasticities for 15 commodity groups in four European countries. Since Armington elasticities are found to be rather low on average, researchers may want to reconsider the device of using high values of Armington elasticities in CGE models to avoid unrealistic competitiveness effects or emission leakage rates associated with energy or carbon taxes or other forms of energy-related regulation. Estimated elasticities tend to be higher in the case of machinery and other investment goods than in the case of primary products, ores and chemicals, as well as consumer goods
Stress energy of elastic globe in curved space and a slip-out force
International Nuclear Information System (INIS)
Sokolov, S.N.
1990-01-01
The energy of stresses in an elastic globe in the flat space and in curved space is expressed through scalar invariants of the curved space. This energy creates an additional force acting on elastic bodies in a gravitational field. 4 refs
International Nuclear Information System (INIS)
Bui, Huy Duong
1969-01-01
In this research thesis on metal strain hardening, the author first discusses the issue of passing from microscopic values to corresponding macroscopic values. If there is generally a correspondence between them, it is not the case for plastic strain. Thus, the author studies the general properties of the boundary of the macroscopic plastic field with respect to single-crystal elastic boundaries. In the second part, the author reports an experimental study of the evolution of the elastic field boundary. In the third part, he develops elastic-plastic behaviour laws for an aggregate of cubic crystals. The objectives are to report experimental results in a more satisfying way than previous studies, and to obtain acceptable physical laws while keeping some properties of conventional laws in order to ensure the solution uniqueness, and to establish minimum principles similar to those of Nodge-Prager and of Greenberg. In order to do so, he introduces a new hypothesis: there is a statistic scattering in initial thresholds of crystals
The price elasticity of energy demand. The state of affairs in 1998
International Nuclear Information System (INIS)
De Groot, A.; Muskens, J; Velthuijsen, J.W.
1998-11-01
Within the framework of further development of energy taxes it is important to investigate the validity of the present tools by means of which the effects of energy taxes can be predicted. The estimation of the price elasticity of the energy consumption is an important aspect in the use of those tools. The results of a 1990 study on the possible effects of an energy tax are re-evaluated, based on a state-of-the-art of theoretical and empirical economic science with respect to elasticities. Also attention is paid to how the elasticities, as applied in relevant energy models, must be assessed. 43 refs
A new approach to measure the elasticity modulus for ceramics using the deformation energy method
International Nuclear Information System (INIS)
Foschini, Cesar R.; Souza, Edson A.; Borges, Ana F. S.; Pintao, Carlos A.
2016-01-01
This paper presents an alternative method to measure the modulus of elasticity to traction, E, for relatively limited sample sizes. We constructed a measurement system with a Force sensor (FS) and a Rotation movement sensor (RMS) to obtain a relationship between force (F) and bending (ΔL). It was possible by calculating the strain energy and the work of a constant force to establish a relationship between these quantities; the constant of proportionality in this relationship depends on E, I and L. I and L are the moment of inertia of the uniform cross-section in relation to an oriented axis and length, respectively, of the sample for bending. An expression that could achieve the value of E was deduced to study samples of Y-TZP ceramics. The advantages of this system compared to traditional systems are its low cost and practicality in determining E
Plastic incompatibility stresses and stored elastic energy in plastically deformed copper
Energy Technology Data Exchange (ETDEWEB)
Baczmanski, A. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland)], E-mail: baczman@ftj.agh.edu.pl; Hfaiedh, N.; Francois, M. [LASMIS, Universite de Technologie de Troyes, 11 rue Marie Curie, B.P. 2060, 10010 Troyes (France); Wierzbanowski, K. [Faculty of Physics and Applied Computer Science, AGH-University of Science and Technology, al. Mickiewicza 30, 30-059 Krakow (Poland)
2009-02-15
The X-ray diffraction method and theoretical model of elastoplastic deformation were used to examine the residual stresses in polycrystalline copper. To this end, the {l_brace}2 2 0{r_brace} strain pole figures were determined for samples subjected to different magnitudes of tensile deformation. Using diffraction data and the self-consistent model, the tensor of plastic incompatibility stress was found for each orientation of a polycrystalline grain. Crystallographic textures, macroscopic and second-order residual stresses were considered in the analysis. As a result, the distributions of elastic stored energy and von Mises equivalent stress were presented in Euler space and correlated with the preferred orientations of grains. Moreover, using the model prediction, the variation of the critical resolved shear stress with grain orientation was determined.
A new approach to measure the elasticity modulus for ceramics using the deformation energy method
Energy Technology Data Exchange (ETDEWEB)
Foschini, Cesar R.; Souza, Edson A. [Dept. of EngineeringFeb-UNESPBauru (Brazil); Borges, Ana F. S. [Dept. of MaterialFOB-USP, Bauru (Brazil); Pintao, Carlos A. [Dept. of PhysicsFC-UNESP, Bauru (Brazil)
2016-08-15
This paper presents an alternative method to measure the modulus of elasticity to traction, E, for relatively limited sample sizes. We constructed a measurement system with a Force sensor (FS) and a Rotation movement sensor (RMS) to obtain a relationship between force (F) and bending (ΔL). It was possible by calculating the strain energy and the work of a constant force to establish a relationship between these quantities; the constant of proportionality in this relationship depends on E, I and L. I and L are the moment of inertia of the uniform cross-section in relation to an oriented axis and length, respectively, of the sample for bending. An expression that could achieve the value of E was deduced to study samples of Y-TZP ceramics. The advantages of this system compared to traditional systems are its low cost and practicality in determining E.
High-energy elastic and quasi-elastic deuteron-nucleus scattering
International Nuclear Information System (INIS)
Tekou, Amouzou
1974-01-01
A study is made of deuteron-nucleus elastic and quasi-elastic scattering and the connection between the opaque nucleus model and the Glauber model is pointed out. The contributions to different cross-sections of the collisions in which the nucleus, excited by one of the nucleons of the deuteron, is brought back to the ground state by the other nucleon is analysed. Coherent deuteron disintegration is found to be highly improbable when the target nucleus is heavy and incoherent disintegration accounts for nearly all the deuteron disintegration. Thus a correct comparison between theoretical and experimental data on proton stripping must take the incoherent deuteron disintegration into consideration
Low energy elastic electron scattering from polyatomic targets
International Nuclear Information System (INIS)
Khakoo, M A
2008-01-01
New differential cross-section measurements for elastic electron scattering from ethylene (C 2 H 4 ), three primary alcohols, methanol (CH 3 OH), ethanol (C 2 H 5 OH) and propanol (C 3 H 7 OH) are reported. The measurements are obtained using the relative flow method with a thin aperture as the collimating target gas source. The relative flow method is applied without the molecular diameters restriction imposed by the relative flow pressure condition on helium (the calibrating gas) and the unknown gases (the primary alcohols). The experimental data were taken at incident electron energies of 1eV, 2eV, 5eV, 10eV, 15eV, 20eV, 30eV, 50eV and 100eV, but only a brief survey of these results will be made here. The experimental results are compared to theoretical differential cross-sections are obtained by using the variational multi-channel Schwinger method. Initial comparisons between theory and experiment show that present theory is well-able to model low electron scattering from these polyatomic targets.
Empirical assessment of energy-price policies: the case for cross-price elasticities
International Nuclear Information System (INIS)
Frondel, M.
2004-01-01
Evaluations of energy-price policies are necessarily based on measures of the substitution of energy and non-energy inputs. Facing a variety of substitution elasticities, the central question arises which measure would be appropriate. Apparently, for a long time, this question has not been at issue: Allen's elasticities of substitution (AES) have been the most-used measures in applied production analysis. This paper's main contribution is an instructive survey of the origin of substitution measures and of the trinity of empirical substitution elasticities-AES, cross-price elasticities, and the Morishima elasticities of substitution (MES)-with particular emphasis on their interpretations and the perspectives that will be captured by these measures. This survey clarifies why classical cross-price elasticities are to be preferred for many practical purposes. Berndt and Wood's (Rev. Econom. Stat. 57(1975) 259) frequently applied data set of US manufacturing is used to illustrate why assessments of energy-price policies would be better based on cross-price elasticities like the energy-price elasticity of capital, rather than on AES or MES. (author)
Empirical assessment of energy-price policies: the case for cross-price elasticities
International Nuclear Information System (INIS)
Frondel, Manuel
2004-01-01
Evaluations of energy-price policies are necessarily based on measures of the substitution of energy and non-energy inputs. Facing a variety of substitution elasticities, the central question arises which measure would be appropriate. Apparently, for a long time, this question has not been at issue: Allen's elasticities of substitution (AES) have been the most-used measures in applied production analysis. This paper's main contribution is an instructive survey of the origin of substitution measures and of the trinity of empirical substitution elasticities - AES, cross-price elasticities, and the Morishima elasticities of substitution (MES) - with particular emphasis on their interpretations and the perspectives that will be captured by these measures. This survey clarifies why classical cross-price elasticities are to be preferred for many practical purposes. Berndt and Wood's (Rev. Econom. Stat. 57 (1975) 259) frequently applied data set of US manufacturing is used to illustrate why assessments of energy-price policies would be better based on cross-price elasticities like the energy-price elasticity of capital, rather than on AES or MES
Ebrahimi, Farzad; Dabbagh, Ali
2017-02-01
Main object of the present research is an exact investigation of wave propagation responses of smart rotating magneto-electro-elastic (MEE) graded nanoscale plates. In addition, effective material properties of functionally graded (FG) nanoplate are presumed to be calculated using the power-law formulations. Also, it has been tried to cover both softening and stiffness-hardening behaviors of nanostructures by the means of employing nonlocal strain gradient theory (NSGT). Due to increasing the accuracy of the presented model in predicting shear deformation effects, a refined higher-order plate theory is introduced. In order to cover the most enormous circumstances, maximum amount of load generated by plate’s rotation is considered. Furthermore, utilizing a developed form of Hamilton’s principle, containing magneto-electric effects, the nonlocal governing equations of MEE-FG rotating nanoplates are derived. An analytical solution is obtained to solve the governing equations and validity of the solution method is proven by comparing results from present method with those of former attempts. At last, outcomes are plotted in the framework of some figures to show the influences of various parameters such as wave number, nonlocality, length scale parameter, magnetic potential, electric voltage, gradient index and angular velocity on wave frequency, phase velocity and escape frequency of the examined nanoplate.
Finite element prediction of elastic strains in beryllium compact tension specimens
International Nuclear Information System (INIS)
Guerra, F.; Varma, R.; Bourke, M.
1997-01-01
Three-dimensional finite element (FE) calculations using ABAQUS version 5.5.9 were compared to neutron diffraction measurements of a loaded, pre-cracked beryllium compact tension (CT) specimens. The objective was to validate the FE results with the experimental open-quotes elastic strainclose quotes measurements. Then the FE calculations could be used to study residual stress and other aspects of these problems in the unloaded state and the crack tip stress in the loaded state which is hard to measure experimentally. A graded FE mesh was focused on the regions containing high strain gradients, the smallest elements were approximately 0.5 mm x 0.5 mm x 0.4 mm. A standard 20-node brick element model was complemented by a model with 1/4-point elements at the crack tip. Since the neutron diffraction measurements provided a volume average of approximately a cube of edge 3.0 mm, various averaging (or integrating) techniques were used on the FE results. Several integration schemes showed good agreement with the experimental results
Kenigsberg, A.; Saffer, D. M.; Riviere, J.; Marone, C.
2017-12-01
Ultrasonic/seismic waves are widely used for probing fault zone elastic and mechanical properties (gouge composition, frictional strength, density) and elastic properties (Vp, Vs, bulk and shear moduli), as it can provide insight into key processes and fault properties during shearing. These include fabric and force chain formation, porosity evolution, and fault zone stiffness, which are in turn factors in fault slip, damage, and healing. We report on a suite of direct shear experiments on synthetic fault gouge composed of 50% smectite /50% quartz at a normal stress of 25 MPa, in which we use ultrasonic wave transmission to continuously monitor compressional and shear wave velocities (Vp, Vs) up to shear strains of 25, while simultaneously measuring friction and monitoring the evolution of density and porosity. We find that wavespeeds vary with shear strain, due to fabric development and the evolution of density and porosity. The coefficient of friction peaks at μ .47 at a shear strain of .5 - 1, decreases to a steady state value of μ .43 by shear strains of 4.5- 6 and then remains rather constant to shear strains of 6 - 25, consistent with previous work. Density increases rapidly from 1.78 g/cm3 to 1.83 g/cm3 at shear strains from 0-2 (porosity decreases from 33% to 25% over that range), and then more gradually increases to a density of 2.08 g/cm3 (porosity of 21%) at a shear strain of 25. Vp increases from 2400 m/s to 2900 m/s during the onset of shear until a shear strain of 3, and then decreases to 2400-2500 by shear strain of 7-9. At shear strains above 9, Vp slowly increases as the layer becomes denser and less porous. We interpret the co-evolving changes in friction, porosity, and elastic moduli/wavespeed to reflect fabric development and alignment of clay particles as a function of shearing. More specifically, the decrease in Vp at a shear strain of 3 reflects the clay particles gradually aligning. Once the particles are aligned, the gradual increase of
Invester Response to Consumer Elasticity, Nordic Energy Research
DEFF Research Database (Denmark)
Jensen, Stine Grenaa; Meibom, Peter; Ravn, Hans V.
2004-01-01
. The simulated investment decisions are taken in a stochastic, dynamic setting, where a key point is the timing of the investment decision in relation to the gathering of new information relative to the stochastic elements. Based on this, the consequences of the development in consumer price elasticity......, and it is generally assumed that the demand side has an important role in this, and increasingly so. However, since consumers have not earlier had the incentive to respond to electricity prices, no reliable estimate of demand elasticity is known. The purpose of the present study is to analyse the role of electricity...... demand elasticity for investments in new electricity production capacity. Electricity price scenarios generated with a partial equilibrium model (Balmorel) are combined with a model of investment decisions. In this, various scenarios concerning the development in the demand elasticity are used...
International Nuclear Information System (INIS)
Mirzade, Fikret Kh.
2005-01-01
The propagation of longitudinal strain wave in a plate with quadratic nonlinearity of elastic continuum was studied in the context of a model that takes into account the joint dynamics of elastic displacements in the medium and the concentration of the nonequilibrium laser-induced point defects. The input equations of the problem are reformulated in terms of only the total displacements of the medium points. In this case, the presence of structural defects manifests itself in the emergence of a delayed response of the system to the propagation of the strain-related perturbations, which is characteristic of media with relaxation or memory. The model equations describing the nonlinear displacement wave were derived with allowance made for the values of the relaxation parameter. The influence of the generation and relaxation of lattice defects on the propagation of this wave was analyzed. It is shown that, for short relaxation times of defects, the strain can propagate in the form of shock fronts. In the case of longer relaxation times, shock waves do not form and the strain wave propagates only in the form of solitary waves or a train of solitons. The contributions of the finiteness of the defect-recombination rate to linear and nonlinear elastic modulus, and spatial dispersion are determined
International Nuclear Information System (INIS)
Rivera, A; Garcia, G; Olivares, J; Crespillo, M L; Agulló-López, F
2011-01-01
The elastic strain/stress fields (halo) around a compressed amorphous nano-track (core) caused by a single high-energy ion impact on LiNbO 3 are calculated. A method is developed to approximately account for the effects of crystal anisotropy of LiNbO 3 (symmetry 3m) on the stress fields for tracks oriented along the crystal axes (X, Y or Z). It only considers the zero-order (axial) harmonic contribution to the displacement field in the perpendicular plane and uses effective Poisson moduli for each particular orientation. The anisotropy is relatively small; however, it accounts for some differential features obtained for irradiations along the crystallographic axes X, Y and Z. In particular, the irradiation-induced disorder (including halo) and the associated surface swelling appear to be higher for irradiations along the X- or Y-axis in comparison with those along the Z-axis. Other irradiation effects can be explained by the model, e.g. fracture patterns or the morphology of pores after chemical etching of tracks. Moreover, it offers interesting predictions on the effect of irradiation on lattice parameters.
Forward diffraction amplitude of pp and pp elastic scattering at accelerator energies
International Nuclear Information System (INIS)
Kawasaki, M.; Maehara, T.; Yonezawa, M.
2004-01-01
A simple relation between the total cross section and the forward exponential slope of the elastic differential cross section of pp and pp scattering is indicated. An interpretation of this relation is presented as the formation of a black-disk structure for the elastic diffraction interaction of hadron-hadron scattering at the nonasymptotic energy region
International Nuclear Information System (INIS)
Hojjati, M.H.; Jafari, S.
2009-01-01
Analytical solutions for the elastic-plastic stress distribution in rotating annular disks with uniform and variable thicknesses and densities are obtained under plane stress assumption. The solution employs a technique called the homotopy perturbation method. A numerical solution of the governing differential equation is also presented based on the Runge-Kutta's method for both elastic and plastic regimes. The analysis is based on Tresca's yield criterion, its associated flow rule and linear strain hardening. The results of the two methods are compared and generally show good agreement. It is shown that, depending on the boundary conditions used, the plastic core may contain one, two or three different plastic regions governed by different mathematical forms of the yield criterion. Four different stages of elastic-plastic deformation occur. The expansion of these plastic regions with increasing angular velocity is obtained together with the distributions of stress and displacement
Elastic energy and metastable phase equilibria for coherent mixtures in cubic systems
International Nuclear Information System (INIS)
Williams, R.O.
1979-02-01
Expressions were derived for the elastic energy due to coherency for cubic systems for an isotropic structure and for (100) or (111) habit planes for a lamellar structure. For the metastable equilibria the usual tangent compositions are replaced by compositions that are tangent to the elastic energy curve. For a loss of coherency there is an energy decrease due to the elastic effects and a further decrease associated with compositional changes. Information contained within this treatment permits calculation of the x-ray diffraction effects for such structures
The economic concept of elasticity and their incidence in the Colombian energy market
International Nuclear Information System (INIS)
Perez Bedoya, Edigson
1997-01-01
There are two factors that affect the elasticity, in the first place the readiness of substitutes and in second place, the number of uses that can be given, the more numerous and better they are the substitutes, will be better the elasticity. The goods that have scarce and bad substitutes will Always spread to have small elasticity. The goods with many substitutes will spread to have great elasticity; if the demand is classified in elastic or inelastic it is an important consideration, especially for the energy politics, in the relative thing to market of specific goods, in this case the electric power. If the coefficient of elasticity of the electric power was very elastic, this would imply that an increase in the rate will generate a reduction proportionally in the energy consumption bigger, the companies that they offer or they distribute energy in the case of the electricity for example, they would obtain a smaller entrance for the sale of the electric power kWh. In the practice it is difficult that it happens, for the difficulty of finding substitutes for the electric power, in other words because the elasticity of the electric power demand is inelastic. If the national government establishes a minimum rate above the price of the market balance, the kWh sales, they could decrease, the same as the entrance of the companies of the electric sector, unless the guarantee price is accompanied by minimum quotas of purchase
Energy Technology Data Exchange (ETDEWEB)
Levine, Lyle E. [National Institute of Standards and Technology (NIST); Larson, Ben C [ORNL; Yang, Wenge [ORNL; Kassner, Michael E. [University of Southern California; Tischler, Jonathan Zachary [ORNL; Delos-Reyes, Michael A. [University of Southern California; Fields, Richard J. [National Institute of Standards and Technology (NIST); Liu, Wenjun [ORNL
2006-01-01
The distribution of elastic strains at the submicrometre length scale within deformed metal single crystals has remarkably broad implications for our understanding of important physical phenomena. These include the evolution of the complex dislocation structures that govern mechanical behaviour within individual grains, the transport of dislocations through such structures, changes in mechanical properties that occur during reverse loading (for example, sheet-metal forming and fatigue), and the analyses of diffraction line profiles for microstructural studies of these phenomena.
International Nuclear Information System (INIS)
Rack, H.J.; Knorovsky, G.A.
1978-09-01
Stress-strain data which describes the influence of strain rate and temperature on the mechanical response of materials presently being used for light water reactor fuel shipping containers have been assembled. Selection of data has been limited to that which is suitable for use in finite-element elastic--plastic analysis of shipping containers (e.g., they must include complete material history profiles). Based on this information, recommendations have been made for further work which is required to complete the necessary data base
RGO-coated elastic fibres as wearable strain sensors for full-scale detection of human motions
Mi, Qing; Wang, Qi; Zang, Siyao; Mao, Guoming; Zhang, Jinnan; Ren, Xiaomin
2018-01-01
In this study, we chose highly-elastic fabric fibres as the functional carrier and then simply coated the fibres with reduced graphene oxide (rGO) using plasma treatment, dip coating and hydrothermal reduction steps, finally making a wearable strain sensor. As a result, the full-scale detection of human motions, ranging from bending joints to the pulse beat, has been achieved by these sensors. Moreover, high sensitivity, good stability and excellent repeatability were realized. The good sensing performances and economical fabrication process of this wearable strain sensor have strengthened our confidence in practical applications in smart clothing, smart fabrics, healthcare, and entertainment fields.
Elastic energy of the flux lines in the matter. The interaction energy
International Nuclear Information System (INIS)
Dolocan, Voicu
1999-01-01
A theoretical treatment of the interaction between the bodies, by using the elastic coupling through the flux lines, is presented. We show that the elastic coupling through the flux lines gives an interaction energy between two superconductor or magnetic pieces, which is inversely proportional to the distance between the two bodies. We extend this concept to the gravitational and electrical interaction. For the electrical interaction one obtains that the statics interaction energy is inversely proportional to the distance between the charges, as in the Coulomb's law, while the oscillatory interaction is inversely proportional to the third power of the distance between the charged particles. This means that at shorter distance an attraction between the two charged particles of the same sign, may appear if the oscillatory energy of interaction is larger than the statics energy of interaction. In addition, the oscillatory interaction appears only as a virtual process. We apply these results to the deuteron and to the electron pairs in superconductors. Also, for the gravitation one obtains that the interaction energy is inversely proportional to the distance between the centers of the two bodies as in Newton's law. (author)
A meta-analysis on the price elasticity of energy demand
International Nuclear Information System (INIS)
Labandeira, Xavier; Labeaga, José M.; López-Otero, Xiral
2017-01-01
Price elasticities of energy demand have become increasingly relevant in estimating the socio-economic and environmental effects of energy policies or other events that influence the price of energy goods. Since the 1970s, a large number of academic papers have provided both short and long-term price elasticity estimates for different countries using several models, data and estimation techniques. Yet the literature offers a rather wide range of estimates for the price elasticities of demand for energy. This paper quantitatively summarizes the recent, but sizeable, empirical evidence to facilitate a sounder economic assessment of (in some cases policy-related) energy price changes. It uses meta-analysis to identify the main factors affecting short and long term elasticity results for energy, in general, as well as for specific products, i.e., electricity, natural gas, gasoline, diesel and heating oil. - Highlights: • An updated and wider meta-analysis on price elasticities of energy demand. • Energy goods are shown to be price inelastic both in the short and long-term. • Results are relevant for a proper design and implementation of energy policies. • Our results refer to energy, as a whole, and specific energy goods.
Theoretical predictions for pp and panti p elastic scattering in the TeV energy domain
International Nuclear Information System (INIS)
Bourrely, C.; Martin, A.
1984-01-01
We present theoretical predictions on total cross-sections and elastic scattering in the TeV energy domain obtained from the present experimental situation at the ISR and the panti p Collider. (orig.)
thermoelastic waves without energy dissipation in an elastic plate ...
African Journals Online (AJOL)
cistvr
The first generalization, for isotropic bodies, is due to Lord & Shulman (1967) who obtained a wave-type heat equation by postulating a new law of heat conduction to replace the classical Fourier's law. ...... In this paper we have studied the thermoelastic interactions due to the punching of a cylindrical hole in an elastic plate ...
The Current Status of High Energy Elastic Scattering
Block, Martin M.; Kang, Kyungsik; White, Alan R.
The recent total cross section, σtot, and ρ-value results from the Fermilab Tevatron Collider experiments,1,2 presented at the 4th “Blois” Workshop on Elastic and Diffractive Scattering, held at Elba in May 1991, provide a natural springboard from which to launch a focused review of the field.
Stress fields and energy of disclination-type defects in zones of localized elastic distortions
Sukhanov, Ivan I.; Tyumentsev, Alexander N.; Ditenberg, Ivan A.
2016-11-01
This paper studies theoretically the elastically deformed state and analyzes deformation mechanisms in nanocrystals in the zones of localized elastic distortions and related disclination-type defects, such as dipole, quadrupole and multipole of partial disclinations. Significant differences in the energies of quadrupole and multipole configurations in comparison with nanodipole are revealed. The mechanism of deformation localization in the field of elastic distortions is proposed, which is a quasi-periodic sequence of formation and relaxation of various disclination ensembles with a periodic change in the energy of the defect.
High-Energy antipp and pp Elastic Scattering and Nucleon Structure
International Nuclear Information System (INIS)
Islam, M.M.; Innocente, V.; Fearnley, T.; Sanguinetti, G.
1987-01-01
High-energy antipp and pp elastic data from the CERN Collider and the ISR are analyzed in the nucleon valence core model. Diffraction is described by a profile function that incorporates crossing symmetry and saturation of Froissart-Martin bound. The model is found to provide a very satisfactory description of the elastic scattering over the whole range of energy and momentum transfer. Implications of the analysis on QCD models of nucleon structure are pointed out
High-Energy antipp and pp Elastic Scattering and Nucleon Structure
Energy Technology Data Exchange (ETDEWEB)
Islam, M.M.; Innocente, V.; Fearnley, T.; Sanguinetti, G.
1987-07-15
High-energy antipp and pp elastic data from the CERN Collider and the ISR are analyzed in the nucleon valence core model. Diffraction is described by a profile function that incorporates crossing symmetry and saturation of Froissart-Martin bound. The model is found to provide a very satisfactory description of the elastic scattering over the whole range of energy and momentum transfer. Implications of the analysis on QCD models of nucleon structure are pointed out.
Hanson, David E.
2011-08-01
Based on recent molecular dynamics and ab initio simulations of small isoprene molecules, we propose a new ansatz for rubber elasticity. We envision a network chain as a series of independent molecular kinks, each comprised of a small number of backbone units, and the strain as being imposed along the contour of the chain. We treat chain extension in three distinct force regimes: (Ia) near zero strain, where we assume that the chain is extended within a well defined tube, with all of the kinks participating simultaneously as entropic elastic springs, (II) when the chain becomes sensibly straight, giving rise to a purely enthalpic stretching force (until bond rupture occurs) and, (Ib) a linear entropic regime, between regimes Ia and II, in which a force limit is imposed by tube deformation. In this intermediate regime, the molecular kinks are assumed to be gradually straightened until the chain becomes a series of straight segments between entanglements. We assume that there exists a tube deformation tension limit that is inversely proportional to the chain path tortuosity. Here we report the results of numerical simulations of explicit three-dimensional, periodic, polyisoprene networks, using these extension-only force models. At low strain, crosslink nodes are moved affinely, up to an arbitrary node force limit. Above this limit, non-affine motion of the nodes is allowed to relax unbalanced chain forces. Our simulation results are in good agreement with tensile stress vs. strain experiments.
Xu, Jingping; Tripathy, Sakya; Rubin, Jonathan M; Stidham, Ryan W; Johnson, Laura A; Higgins, Peter D R; Kim, Kang
2012-03-01
Strain developed under quasi-static deformation has been mostly used in ultrasound elasticity imaging (UEI) to determine the stiffness change of tissues. However, the strain measure in UEI is often less sensitive to a subtle change of stiffness. This is particularly true for Crohn's disease where we have applied strain imaging to the differentiation of acutely inflamed bowel from chronically fibrotic bowel. In this study, a new nonlinear elastic parameter of the soft tissues is proposed to overcome this limit. The purpose of this study is to evaluate the newly proposed method and demonstrate its feasibility in the UEI. A nonlinear characteristic of soft tissues over a relatively large dynamic range of strain was investigated. A simplified tissue model based on a finite element (FE) analysis was integrated with a laboratory developed ultrasound radio-frequency (RF) signal synthesis program. Two-dimensional speckle tracking was applied to this model to simulate the nonlinear behavior of the strain developed in a target inclusion over the applied average strain to the surrounding tissues. A nonlinear empirical equation was formulated and optimized to best match the developed strain-to-applied strain relation obtained from the FE simulation. The proposed nonlinear equation was applied to in vivo measurements and nonlinear parameters were further empirically optimized. For an animal model, acute and chronic inflammatory bowel disease was induced in Lewis rats with trinitrobenzene sulfonic acid (TNBS)-ethanol treatments. After UEI, histopathology and direct mechanical measurements were performed on the excised tissues. The extracted nonlinear parameter from the developed strain-to-applied strain relation differentiated the three different tissue types with 1.96 ± 0.12 for normal, 1.50 ± 0.09 for the acutely inflamed and 1.03 ± 0.08 for the chronically fibrotic tissue. T-tests determined that the nonlinear parameters between normal, acutely inflamed and fibrotic tissue
International Nuclear Information System (INIS)
Varga, D.; Toekesi, K.; Berenyi, Z.; Toth, J.; Koever, L.
2004-01-01
Complete text of publication follows. Observation of the hydrogen peak is either challenging or impossible task for the conventional electron spectroscopy. Hydrogen was observed earlier in electron scattering experiments using transmission geometry and formvar film. In this work we show an alternative way for the detection of hydrogen peak analyzing the spectra of elastically backscattered electrons from polyethylene ((CH 2 ) n ). We take advantage of the fact that the elastic peak from polyethylene split into carbon and hydrogen components. The energy of the elastically scattered electrons is shifted from the nominal values due to the energy transfer between the primary electron and the target atoms (recoil effect). Due to the motion of the scattering atoms, a broadering of the energy width of the spectra takes place. We performed Monte Carlo simulation for 2 keV electrons penetrated and elastically backscattered from polyethylene sample. In our calculations both the elastic and inelastic scattering events were taken into account. We further assume that the thermal motion of the target atoms follows the Maxwell-Boltzmann energy distribution. After each elastic scattering the recoil energy was calculated according to ref Fig. 1 shows the geometric configuration used in the calculation. The initial angle of incident beam (θ) was 50 deg. Fig. 2 shows the gray scale plot of the intensity of electrons backscattered elastically from polyethylene. The separation between the carbon and hydrogen peaks is clearly seen. Our results show that the multiple electron scattering causes only minor changes in the energy shifts and broadenings of elastic peaks. Moreover, our simulations are in good agreement with our experimental observations. (author)
Transformation of Elastic Wave Energy to the Energy of Motion of Bodies
Vesnitskiĭ, A. I.; Lisenkova, E. E.
2002-01-01
The motion of a body along an elastic guide under the effect of an incident wave is considered. An equation describing the longitudinal motion of a body along an arbitrary guide is derived from the laws governing the energy and momentum variations for the case when the incident wave generates a single reflected wave. The equations that describe the motion of a body along a string and along a beam corresponding to the Bernoulli-Euler model are considered as examples. The process of the body acceleration along a beam of the aforementioned type is investigated. For the subcritical velocities, the law governing the motion of the body and the ratio of the kinetic energy variation to the energy supplied to the body are determined.
Aero-Hydro-Elastic Simulation Platform for Wave Energy Systems and floating Wind Turbines
DEFF Research Database (Denmark)
Kallesøe, Bjarne Skovmose
This report present results from the PSO project 2008-1-10092 entitled Aero-Hydro-Elastic Simulation Platform for Wave Energy Systems and floating Wind Turbines that deals with measurements, modelling and simulations of the world’s first combined wave and wind energy platform. The floating energy...
Directory of Open Access Journals (Sweden)
Kevin J. Maloney
2013-08-01
Full Text Available Ordered periodic microlattices with densities from 0.5 mg/cm3 to 500 mg/cm3 are fabricated by depositing various thin film materials (Au, Cu, Ni, SiO2, poly(C8H4F4 onto sacrificial polymer lattice templates. Young's modulus and strength are measured in compression and the density scaling is determined. At low relative densities, recovery from compressive strains of 50% and higher is observed, independent of lattice material. An analytical model is shown to accurately predict the transition between recoverable “pseudo-superelastic” and irrecoverable plastic deformation for all constituent materials. These materials are of interest for energy storage applications, deployable structures, and for acoustic, shock, and vibration damping.
International Nuclear Information System (INIS)
Iadicola, Mark A.; Gnäupel-Herold, Thomas H.
2012-01-01
Accurate measurement of stresses by X-ray diffraction requires accurate X-ray elastic constants. Calibration experiments are one method to determine these for a specific material in a specific condition. In this paper, uniaxial tension experiments are used to investigate the variation of these constants after uniaxial and equal-biaxial plastic deformation for an aluminum alloy (AA5754-O) of interest to the automotive industry. These data are critical for accurate measurement of the biaxial mechanical properties of the material using a recent experimental method combining specialized sheet metal forming equipment with portable X-ray diffraction equipment. The measured effective X-ray elastic constants show some minor variation with increased plastic deformation, and this behavior was found to be consistent for both uniaxially and equal-biaxially strained samples. The use of two average values for effective X-ray elastic constants, one in the rolling direction and one transverse to the rolling direction of the sheet material, is shown to be of sufficient accuracy for the combined tests of interest. Comparison of uniaxial data measured using X-ray diffraction and standard methods show good agreement, and biaxial stress–strain results show good repeatability. Additionally, the calibration data show some non-linear behavior, which is analyzed in regards to crystallographic texture and intergranular stress effects. The non-linear behavior is found to be the result of intergranular stresses based on comparison with additional measurements using other X-ray diffraction equipment and neutron diffraction.
International Nuclear Information System (INIS)
Tőkési, K.; Varga, D.; Berényi, Z.
2015-01-01
We present results of theoretical and experimental studies of the spectra of electrons backscattered elastically from polyethylene in the primary energy range between 1 and 5 keV. The experiments were performed using a high energy resolution electron spectroscopy. The theoretical interpretation is based on a Monte Carlo simulation of the recoil and Doppler effects. The separation between the carbon and hydrogen peak in the energy distributions is shown as a function of the primary electron energy. The simulations give many partial distributions separately, depending on the number of elastic scatterings (single, and multiple scatterings of different types). We show our results for intensity ratios, peak shifts and broadenings. We also present detailed analytical calculations for the main parameters of a single scattering. Finally, we present a qualitative comparison with the experimental data. We find our resulting energy distribution of elastically scattered electrons to be in good agreement with our measurements
Neff, Patrizio; Lankeit, Johannes; Ghiba, Ionel-Dumitrel; Martin, Robert; Steigmann, David
2015-08-01
We consider a family of isotropic volumetric-isochoric decoupled strain energies based on the Hencky-logarithmic (true, natural) strain tensor log U, where μ > 0 is the infinitesimal shear modulus, is the infinitesimal bulk modulus with the first Lamé constant, are dimensionless parameters, is the gradient of deformation, is the right stretch tensor and is the deviatoric part (the projection onto the traceless tensors) of the strain tensor log U. For small elastic strains, the energies reduce to first order to the classical quadratic Hencky energy which is known to be not rank-one convex. The main result in this paper is that in plane elastostatics the energies of the family are polyconvex for , extending a previous finding on its rank-one convexity. Our method uses a judicious application of Steigmann's polyconvexity criteria based on the representation of the energy in terms of the principal invariants of the stretch tensor U. These energies also satisfy suitable growth and coercivity conditions. We formulate the equilibrium equations, and we prove the existence of minimizers by the direct methods of the calculus of variations.
Variation of the energy release rate as a crack approaches and passes through an elastic inclusion
Li, Rongshun; Chudnovsky, A.
1993-01-01
The variation of the energy release rate (ERP) at the tip of a crack penetrating an elastic inclusion is analyzed using an approach involving modeling the random array of microcracks or other defects by an elastic inclusion with effective elastic properties. Computations are carried out using a finite element procedure. The eight-noded isoparametric serendipity element with the shift of the midpoint to the quarter-point is used to simulate the singularity at the crack tip, and the crack growth is accommodated by implementing a mesh regeneration technique. The ERP values were calculated for various crack tip positions which simulate the process of the crack approaching and penetrating the inclusion.
Representative Stress-Strain Curve by Spherical Indentation on Elastic-Plastic Materials
Directory of Open Access Journals (Sweden)
Chao Chang
2018-01-01
Full Text Available Tensile stress-strain curve of metallic materials can be determined by the representative stress-strain curve from the spherical indentation. Tabor empirically determined the stress constraint factor (stress CF, ψ, and strain constraint factor (strain CF, β, but the choice of value for ψ and β is still under discussion. In this study, a new insight into the relationship between constraint factors of stress and strain is analytically described based on the formation of Tabor’s equation. Experiment tests were performed to evaluate these constraint factors. From the results, representative stress-strain curves using a proposed strain constraint factor can fit better with nominal stress-strain curve than those using Tabor’s constraint factors.
Model of K+p elastic scattering at high energies
International Nuclear Information System (INIS)
Fazal-e-Aleem
1985-01-01
Very recent measurements of the angular distribution for K + p elastic scattering which show a structure near -t = 3.8(GeV/c) 2 , together with the total cross section and ratio of the real and imaginary parts of the scattering amplitude for 50 2 , have been fitted by using a simple Regge-pole model with phenomenological residue functions. The break in the slope near -t = 0.5 (GeV/c) 2 observed in the differential cross section has also been explained
Strain Engineering to Modify the Electrochemistry of Energy Storage Electrodes
Muralidharan, Nitin; Carter, Rachel; Oakes, Landon; Cohn, Adam P.; Pint, Cary L.
2016-01-01
Strain engineering has been a critical aspect of device design in semiconductor manufacturing for the past decade, but remains relatively unexplored for other applications, such as energy storage. Using mechanical strain as an input parameter to modulate electrochemical potentials of metal oxides opens new opportunities intersecting fields of electrochemistry and mechanics. Here we demonstrate that less than 0.1% strain on a Ni-Ti-O based metal-oxide formed on superelastic shape memory NiTi alloys leads to anodic and cathodic peak potential shifts by up to ~30 mV in an electrochemical cell. Moreover, using the superelastic properties of NiTi to enable strain recovery also recovers the electrochemical potential of the metal oxide, providing mechanistic evidence of strain-modified electrochemistry. These results indicate that mechanical energy can be coupled with electrochemical systems to efficiently design and optimize a new class of strain-modulated energy storage materials. PMID:27283872
A dynamic elastic and inelastic scattering theory of high-energy electrons
International Nuclear Information System (INIS)
Wang Zhonglin
1990-01-01
A review is given on the applications of elastic multislice theory for simulating the images and diffractions of reflection electron microscopy. The limitation of this theory is illustrated according to some experimental observations. A generalized elastic and inelastic multislice theory is then introduced from quantum mechanics; its applications for approaching inelastic plasmon excitation and phonon excitation (or thermal diffuse scattering) are discussed. The energy-filtered inelastic high resolution images can be simulated based on this theory
Hashimoto, Yusuke; Bossini, Davide; Johansen, Tom H.; Saitoh, Eiji; Kirilyuk, Andrei; Rasing, Theo
2017-01-01
Using spin-wave tomography (SWaT), we have investigated the excitation and the propagation dynamics of optically-excited magnetoelastic waves, i.e. hybridized modes of spin waves and elastic waves, in a garnet film. By using time-resolved SWaT, we reveal the excitation dynamics of magnetoelastic waves through coherent-energy transfer between optically-excited pure-elastic waves and spin waves via magnetoelastic coupling. This process realizes frequency and wavenumber selective excitation of s...
Optical model theory of elastic electron- and positron-atom scattering at intermediate energies
International Nuclear Information System (INIS)
Joachain, C.J.
1977-01-01
It is stated that the basic idea of the optical model theory is to enable analysis of the elastic scattering of a particle from a complex target by replacing the complicated interactions between the beam and the target by an optical potential, or pseudopotential, in which the incident particle moves. Once the optical potential is determined the original many-body elastic scattering problem reduces to a one-body situation. The resulting optical potential is, however, a very complicated operator, and the formal expressions obtained from first principles for the optical potential can only be evaluated approximately in a few simple cases, such as high energy elastic hadron-nucleus scattering, for the the optical potential can be expressed in terms of two-body hadron-nucleon amplitudes, and the non-relativistic elastic scattering of fast charged particles by atoms. The elastic scattering of an electron or positron by a neutral atom at intermediate energies is here considered. Exchange effects between the projectile and the atomic electrons are considered; also absorption and polarisation effects. Applications of the full-wave optical model have so far only been made to the elastic scattering of fast electrons and positrons by atomic H, He, Ne, and Ar. Agreements of the optical model results with absolute measurements of differential cross sections for electron scattering are very good, an agreement that improves as the energy increases, but deteriorates quickly as the incident energy becomes lower than 50 eV for atomic H or 100 eV for He. For more complex atoms the optical model calculations also appear very encouraging. With regard to positron-atom elastic scattering the optical model results for positron-He scattering differ markedly at small angles from the corresponding electron-He values. It would be interesting to have experimental angular distributions of positron-atom elastic scattering in order to check predictions of the optical model theory. (U.K.)
International Nuclear Information System (INIS)
Vastola, G; Montalenti, F; Miglio, Leo
2008-01-01
Substrate pre-patterning is a new and effective route for growing ordered arrays of heteroepitaxial nanoislands. Here, by exploiting elasticity theory solved by using finite element methods, we show why islands growing inside pits are better relaxed with respect to the flat-substrate case. Pit pre-patterning is demonstrated to be more important than previously realized, allowing for further degrees of freedom in controlling not only positioning but also shape, strain, and coherence of the growing islands. Our results offer a solid interpretation for the recent experimental results obtained by the group of Professor Guenther Bauer.
X-ray diffraction study of elastic strains for modelling γ/γ' two-phase behavior
International Nuclear Information System (INIS)
Durand, L.; Massaoudi, M.; Lavelle, B.
2005-01-01
To describe the two-phase monocrystals behavior, we used has X-rays diffraction method. Our study is based on the mechanics of the continuous media framework in elasticity. We extend to the quadratic structure the study by X-rays developed at the laboratory on cubic materials with coarse grains. We show that the two phases γ and γ' undergo a tetragonal distortion and that the strains are not constant in each phase. Our results are in agreement with a study by the finite element method developed in addition
Impact picture for near-forward elastic scattering up to LHC energies
Soffer, Jacques; Wu, Tai Tsun
2015-01-01
We will recall the main feaatures of an accurate phenomenological model to describe successfully near-forward elastic scattering in a wide energy range, including ISR, SPS and Tevatron colliders. A large step in energy domain is accomplished with the LHC collider, presently running, giving the opportunity to confront the new data with the predictions of our theoretical approach.
α4He elastic scattering at high energies
International Nuclear Information System (INIS)
Usmani, A.A.; Usmani, Q.N.
1988-03-01
Differential cross sections for α 4 He elastic scattering have been calculated at incident α particle momenta of 4.32, 5.07 and 7.0 GeV/c within the framework of the Glauber multiple scattering theory. The full Glauber amplitude is calculated using the Monte Carlo method for evaluating multidimensional integrals. We find that, in general, the more realistic double Gaussian model for the density brings theory closer to experiment as compared to the generally used single Gaussian model. Our results with the double Gaussian model are in fairly good agreement with the experimented data at 4.32 and 5.07 GeV/c. (author). 11 refs, 4 figs, 1 tab
Partitioning of elastic energy in open-cell foams under finite deformations
International Nuclear Information System (INIS)
Harb, Rani; Taciroglu, Ertugrul; Ghoniem, Nasr
2013-01-01
The challenges associated with the computational modeling and simulation of solid foams are threefold—namely, the proper representation of an intricate geometry, the capability to accurately describe large deformations, and the extremely arduous numerical detection and enforcement of self-contact during crushing. The focus of this study is to assess and accurately quantify the effects of geometric nonlinearities (i.e. finite deformations, work produced under buckling-type motions) on the predicted mechanical response of open-cell foams of aluminum and polyurethane prior to the onset of plasticity and contact. Beam elements endowed with three-dimensional finite deformation kinematics are used to represent the foam ligaments. Ligament cross-sections are discretized through a fiber-based formulation that provides accurate information regarding the onset of plasticity, given the uniaxial yield stress–strain data for the bulk material. It is shown that the (hyper-) elastic energy partition within ligaments is significantly influenced by kinematic nonlinearities, which frequently cause strong coupling between the axial, bending, shear and torsional deformation modes. This deformation mode-coupling is uniquely obtained as a result of evaluating equilibrium in the deformed configuration, and is undetectable when small deformations are assumed. The relationship between the foam topology and energy partitioning at various stages of moderate deformation is also investigated. Coupled deformation modes are shown to play an important role, especially in perturbed Kelvin structures where over 70% of the energy is stored in coupled axial-shear and axial-bending modes. The results from this study indicate that it may not always be possible to accurately simulate the onset of plasticity (and the response beyond this regime) if finite deformation kinematics are neglected
Directory of Open Access Journals (Sweden)
Povolotskaya Anna
2018-01-01
Full Text Available The paper reports results of magnetic measurements made on samples of the 12GB pipe steel (strength group X42SS designed for producing pipes to be used in media with high hydrogen sulphide content, both in the initial state and after exposure to hydrogen sulphide, for 96, 192 and 384 hours under uniaxial elastic-plastic tension. At the stage of elastic deformation there is a unique correlation between the coercive force measured on a minor hysteresis loop in weak fields and tensile stress, which enables this parameter to be used for the evaluation of elastic stresses in pipes made of the 12 GB pipe steel under different conditions, including a hydrogen sulphide containing medium. The effect of the value of preliminary plastic strain, viewed as the initial stress-strain state, on the magnetic behaviour of X70 pipe steels under elastic tension and compression is studied. Plastic strain history affects the magnetic behaviour of the material during subsequent elastic deformation since plastic strain induces various residual stresses, and this necessitates taking into account the initial stress-strain state of products when developing magnetic techniques for the determination of their stress-strain parameters during operation.
International Nuclear Information System (INIS)
Gu Fangyu; Zeng Xiao
1990-01-01
It is considered impossible to inspect flaw by using ordinary mechanical measuring methods. In this paper, it is found that the stree and strain distortions of pressure vessel with 2D linear shape crack in the deep location appear the 'cat effect' on the surface of stracture, and that the location and size of the crack can be determined with strain measuring and FEM according to 'cat effect' of strain distortion
Comparison of theory and experiment for elastic-plastic plane-strain crack growth. [AISI 4140 steel
Energy Technology Data Exchange (ETDEWEB)
Hermann, L.; Rice, J.R.
1980-08-01
Recent theoretical results on elastic-plastic plane-strain crack growth are reviewed and experimental results for crack growth in a 4140 steel are discussed in terms of the theoretical concepts. The theory is based on a recent asymptotic analysis of crack surface opening and strain distributions at a quasistatically advancing crack tip in an ideally plastic solid. The analysis is incomplete in that some of the parameters which appear in it are known only approximately, especially at large-scale yielding. Nevertheless, it is sufficient for the derivation of a relation between the imposed loading and amount of crack growth prior to general yielding, based on the assumption that a geometrically similar near-tip crack profile is maintained during growth. The resulting predictions for the variation of J with crack growth are found to fit well to the experimental results obtained on deeply cracked compact specimens.
Gong, LiJie; He, Yan; Tian, Peng; Yan, Yan
2016-07-01
To determine the effect of elastic strain rate ratio method and virtual touch tissue quantification (VTQ) on the diagnosis of breast masses. Sixty female patients with breast cancer, who received surgical treatment in Daqing Oilfield General Hospital, were enrolled. All patients signed the informed consent paperwork and they were treated by routine ultrasound examination, compression elastography (CE) examination, and VTQ examination in turn. Strain ratio (SR) was checked by CE and shear wave velocity (SWV) value was measured by VTQ. The diagnostic values of different methods were evaluated by receiver operating characteristic (ROC) curves in the diagnosis of benign and malignant breast tumors. The maximum diameter and SWV value of the benign tumors were lower than those of the malignant tumors, and the SR ratio of benign masses was higher than that of malignant tumors (Pbreast mass than that used alone.
International Nuclear Information System (INIS)
Sancho, Ferran
2010-01-01
There is a considerable body of literature that has studied whether or not an adequately designed tax swap, whereby an ecotax is levied and some other tax is reduced while keeping government income constant, may achieve a so-called double dividend, that is, an increase in environmental quality and an increase in overall efficiency. Arguments in favor and against are abundant. Our position is that the issue should be empirically studied starting from an actual, non-optimal tax system structure and by way of checking the responsiveness of equilibria to revenue neutral tax regimes under alternate scenarios regarding technological substitution. With the use of a CGE model, we find that the most critical elasticity for achieving a double dividend is the substitution elasticity between labor and capital whereas the elasticity that would generate the highest reduction in carbon dioxide emissions is the substitution elasticity among energy goods.
Energy Technology Data Exchange (ETDEWEB)
Sancho, Ferran [Departament d' Economia, Universitat Autonoma de Barcelona, 08193-Bellaterra (Spain)
2010-06-15
There is a considerable body of literature that has studied whether or not an adequately designed tax swap, whereby an ecotax is levied and some other tax is reduced while keeping government income constant, may achieve a so-called double dividend, that is, an increase in environmental quality and an increase in overall efficiency. Arguments in favor and against are abundant. Our position is that the issue should be empirically studied starting from an actual, non-optimal tax system structure and by way of checking the responsiveness of equilibria to revenue neutral tax regimes under alternate scenarios regarding technological substitution. With the use of a CGE model, we find that the most critical elasticity for achieving a double dividend is the substitution elasticity between labor and capital whereas the elasticity that would generate the highest reduction in carbon dioxide emissions is the substitution elasticity among energy goods. (author)
The role of elastic energy in activities with high force and power requirements: a brief review.
Wilson, Jacob M; Flanagan, Eamonn P
2008-09-01
The purpose of this article is to provide strength and conditioning practitioners with an understanding of the role of elastic energy in activities with high force and power requirements. Specifically, the article covers 1) the nature of elasticity and its application to human participants, 2) the role of elastic energy in activities requiring a stretch-shorten cycle such as the vertical jump, 3) the role of muscular stiffness in athletic performance, 4) the control of muscular stiffness through feedforward and feedback mechanisms, and 5) factors affecting muscular stiffness. Finally, practical applications are provided. In this section, it is suggested that the storage and reuse of elastic energy is optimized at relatively higher levels of stiffness. Because stiffness decreases as fatigue ensues as well as with stretching before an event, the article emphasizes the need for proper preparation phases in a periodized cycle and the avoidance of long static stretches before high-force activities. The importance of teaching athletes to transition from eccentric to concentric movements with minimal time delays is also proposed due to the finding that time delays appear to decrease the reuse of elastic energy. In addition to teaching within the criterion tasks, evidence is provided that minimizing transitions in plyometric training, a technique demonstrated to increase musculotendinous stiffness, can optimize power output in explosive movements. Finally, evidence is provided that training and teaching programs designed to optimize muscular stiffness may protect athletes against sports-related injuries.
The elastic free energy of a tandem modular protein under force.
Valle-Orero, Jessica; Eckels, Edward C; Stirnemann, Guillaume; Popa, Ionel; Berkovich, Ronen; Fernandez, Julio M
2015-05-01
Recent studies have provided a theoretical framework for including entropic elasticity in the free energy landscape of proteins under mechanical force. Accounting for entropic elasticity using polymer physics models has helped explain the hopping behavior seen in single molecule experiments in the low force regime. Here, we expand on the construction of the free energy of a single protein domain under force proposed by Berkovich et al. to provide a free energy landscape for N tandem domains along a continuous polypeptide. Calculation of the free energy of individual domains followed by their concatenation provides a continuous free energy landscape whose curvature is dominated by the worm-like chain at forces below 20 pN. We have validated our free energy model using Brownian dynamics and reproduce key features of protein folding. This free energy model can predict the effects of changes in the elastic properties of a multidomain protein as a consequence of biological modifications such as phosphorylation or the formation of disulfide bonds. This work lays the foundations for the modeling of tissue elasticity, which is largely determined by the properties of tandem polyproteins. Copyright © 2015. Published by Elsevier Inc.
3D printing of highly elastic strain sensors using polyurethane/multiwall carbon nanotube composites
Christ, Josef F.; Hohimer, Cameron J.; Aliheidari, Nahal; Ameli, Amir; Mo, Changki; Pötschke, Petra
2017-04-01
As the desire for wearable electronics increases and the soft robotics industry advances, the need for novel sensing materials has also increased. Recently, there have been many attempts at producing novel materials, which exhibit piezoresistive behavior. However, one of the major shortcomings in strain sensing technologies is in the fabrication of such sensors. While there is significant research and literature covering the various methods for developing piezoresistive materials, fabricating complex sensor platforms is still a manufacturing challenge. Here, we report a facile method to fabricate multidirectional embedded strain sensors using additive manufacturing technology. Pure thermoplastic polyurethane (TPU) and TPU/multiwall carbon nanotubes (MWCNT) nanocomposites were 3D printed in tandem using a low-cost multi-material FDM printer to fabricate uniaxial and biaxial strain sensors with conductive paths embedded within the insulative TPU platform. The sensors were then subjected to a series of cyclic strain loads. The results revealed excellent piezoresistive responses of the sensors with cyclic repeatability in both the axial and transverse directions and in response to strains as high as 50%. Further, while strain-softening did occur in the embedded printed strain sensors, it was predictable and similar to the results found in the literature for bulk polymer nanocomposites. This works demonstrates the possibility of manufacturing embedded and multidirectional flexible strain sensors using an inexpensive and versatile method, with potential applications in soft robotics and flexible electronics and health monitoring.
Wang, Guangqing; Liao, Wei-Hsin; Yang, Binqiang; Wang, Xuebao; Xu, Wentan; Li, Xiuling
2018-05-01
Bistable piezoelectric energy harvesters are being increasingly seen as an alternative to batteries in low-power devices. However, their energy harvesting characteristics are limited. To enhance these, we use a configuration including an elastic magnifier to amplify base excitation and provide sufficient kinetic energy to overcome potential well barriers, thus leading to large-amplitude bistable motion. We derive the distributed parameter mathematical model of this configuration by using Hamilton's principle. We then investigate the nonlinear dynamic behaviors and energetic characteristics and analyze the bifurcation for the equilibrium solution of the model. The simulations and experiments show high electromechanical responses and energy generation characteristics of the proposed system over a broad frequency band. The results suggest that, compared with a typical bistable piezoelectric energy harvester, the proposed energy harvester system with an elastic magnifier can provide higher output over a broader frequency band at lower excitation levels by adjusting the system's mass and stiffness ratios.
Traffic-aware Elastic Optical Networks to leverage Energy Savings
DEFF Research Database (Denmark)
Turus, Ioan; Fagertun, Anna Manolova; Dittmann, Lars
2014-01-01
Because of the static nature of the deployed optical networks, large energy wastage is experienced today in production networks such as Telecom networks . With power-adaptive optical interfaces and suitable grooming procedures, we propose the design of more energy efficient transport networks....... Optical network reconfigurations are performed by GMPLS node controllers according to monitored traffic information. The investigated energy reduction strategies are simulated on two large scale transport networks (DT17 and COST37). The results show that the energy savings obtained by these strategies......-Europea n COST37 network, for both symbol-rate and modulation format adaptations significant savings are obtained . Mixed adaptation (jointly performing symbol-rate and modulation format adaptations) used together with optical grooming allows up to 4 4 % and 4 7 % power savings in DT17 and COST37 networks...
Islam, M M
2013-01-01
We study high energy $\\small{\\rm{pp}}$ and $\\small{\\rm{\\bar {p}p}}$ elastic scattering in the TeV region based on an effective field theory model of the proton. We phenomenologically investigate the main processes underlying elastic scattering and quantitatively describe the measured elastic d$\\small{\\sigma}$/dt at energies 7.0 TeV (LHC $\\small{\\rm{pp}}$), 1.96 TeV (Tevatron $\\small{\\rm{\\bar {p}p}}$), and 0.630 TeV (SPS $\\small{\\rm{\\bar {p}p}}$). Finally, we give our prediction for $\\small{\\rm{pp}}$ elastic d$\\small{\\sigma}$/dt at 14 TeV that will be measured by the TOTEM Collaboration.
Liu, Suihan; Burgueño, Rigoberto
2016-12-01
Axially compressed bilaterally constrained columns, which can attain multiple snap-through buckling events in their elastic postbuckling response, can be used as energy concentrators and mechanical triggers to transform external quasi-static displacement input to local high-rate motions and excite vibration-based piezoelectric transducers for energy harvesting devices. However, the buckling location with highest kinetic energy release along the element, and where piezoelectric oscillators should be optimally placed, cannot be controlled or isolated due to the changing buckling configurations. This paper proposes the concept of stiffness variations along the column to gain control of the buckling location for optimal placement of piezoelectric transducers. Prototyped non-prismatic columns with piece-wise varying thickness were fabricated through 3D printing for experimental characterization and numerical simulations were conducted using the finite element method. A simple theoretical model was also developed based on the stationary potential energy principle for predicting the critical line contact segment that triggers snap-through events and the buckling morphologies as compression proceeds. Results confirm that non-prismatic column designs allow control of the buckling location in the elastic postbuckling regime. Compared to prismatic columns, non-prismatic designs can attain a concentrated kinetic energy release spot and a higher number of snap-buckling mode transitions under the same global strain. The direct relation between the column’s dynamic response and the output voltage from piezoelectric oscillator transducers allows the tailorable postbuckling response of non-prismatic columns to be used as multi-stable energy concentrators with enhanced performance in micro-energy harvesters.
Simulation of vacancy migration energy in Cu under high strain
International Nuclear Information System (INIS)
Sato, K.; Yoshiie, T.; Satoh, Y.; Xu, Q.; Kiritani, M.
2003-01-01
The activation energy for the migration of vacancies in Cu under high strain was calculated by computer simulation using static methods. The migration energy of vacancies was 0.98 eV in the absence of deformation. It varied with the migration direction and stress direction because the distance between a vacancy and its neighboring atoms changes by deformation. For example, the migration energy for the shortest migration distance was reduced to 9.6 and 39.4% of its initial value by 10% compression and 20% elongation, respectively, while that for the longest migration distance was raised to 171.7 by 20% elongation. If many vacancies are created during high-speed deformation, the lowering of migration energy enables vacancies to escape to sinks such as surfaces, even during the shorter deformation period. The critical strain rate above which the strain rate dependence of vacancy accumulation ceases to exist increases with the lowering of vacancy migration energy
Intermediate-energy proton- 4He elastic scattering with a microscopic optical potential
International Nuclear Information System (INIS)
Alexander, Y.; Landau, R.H.
1979-01-01
A microscopic, momentum space, optical potential calculation of elastic p- 4 He scattering is compared with 100-200 MeV data over the full angular range. The least sophisticated potential explains the occurrence and energy dependence of the back angle peak. (Auth.)
Energy Technology Data Exchange (ETDEWEB)
Schultz, D.R.; Krstic, P.S. [Oak Ridge National Lab. TN (United States). Physics Div.
1997-01-01
Due to the present interest in modeling and diagnosing the edge and divertor plasma regions in magnetically confined fusion devices, we have sought to provide new calculations regarding the elastic, excitation, ionization, and charge transfer cross sections in collisions among relevant ions, neutrals, and isotopes in the low-to intermediate-energy regime. We summarize here some of our recent work. (author)
Hydrogen-induced delayed cracking: 1. Strain energy effects on hydrogen solubility
International Nuclear Information System (INIS)
Puls, M.P.
1978-08-01
treatment presented above. We conclude from this that Kearns' data represent the stress-free solvus. The shifts from Kearns' data of the heating and cooling solvi of Erickson and Hardie, determined at fairly high rates of cooling, reflect the mixture of elastic and plastic strain which has occurred in the sample to accommodate the misfit strain between hydride and matrix. Over the range of data from 400 μg/g to 100 μg/g, we estimate the amount of retained elastic strain energy to vary from 2245 J/mol to 1612 J/mol. The corresponding plastic work ranges from 2268 J/mol to 3300 J/mol. (author)
Energy scavenging strain absorber: application to kinetic dielectric elastomer generator
Jean-Mistral, C.; Beaune, M.; Vu-Cong, T.; Sylvestre, A.
2014-03-01
Dielectric elastomer generators (DEGs) are light, compliant, silent energy scavengers. They can easily be incorporated into clothing where they could scavenge energy from the human kinetic movements for biomedical applications. Nevertheless, scavengers based on dielectric elastomers are soft electrostatic generators requiring a high voltage source to polarize them and high external strain, which constitutes the two major disadvantages of these transducers. We propose here a complete structure made up of a strain absorber, a DEG and a simple electronic power circuit. This new structure looks like a patch, can be attached on human's wear and located on the chest, knee, elbow… Our original strain absorber, inspired from a sailing boat winch, is able to heighten the external available strain with a minimal factor of 2. The DEG is made of silicone Danfoss Polypower and it has a total area of 6cm per 2.5cm sustaining a maximal strain of 50% at 1Hz. A complete electromechanical analytical model was developed for the DEG associated to this strain absorber. With a poling voltage of 800V, a scavenged energy of 0.57mJ per cycle is achieved with our complete structure. The performance of the DEG can further be improved by enhancing the imposed strain, by designing a stack structure, by using a dielectric elastomer with high dielectric permittivity.
A theory of low energy π-3He elastic scattering
International Nuclear Information System (INIS)
Geffen, F.M.M. van.
1991-01-01
The main aim of this work is the construction of a first-order optical potential for the scattering of pions by 3 He at low energy with as few approximations as possible. In particular the Fermi motion is treated extremely carefully by using microscopic 3 He wave functions and by performing the complete Fermi-integral. Differential cross-sections and analyzing powers have been calculated. In a detailed comparison between the first-order optical with one which results from using the semi-factored approximation, it became clear that the latter has the following shortcomings: 1. the dependence of the subenergy on the pion-nucleus scattering angle, and 2. the independence of this energy on the relative motion of the spectator nucleons. (author). 101 refs.; 15 figs.; 3 tabs
Driver, Jonathan W; Geyer, Elisabeth A; Bailey, Megan E; Rice, Luke M; Asbury, Charles L
2017-06-19
Disassembling microtubules can generate movement independently of motor enzymes, especially at kinetochores where they drive chromosome motility. A popular explanation is the 'conformational wave' model, in which protofilaments pull on the kinetochore as they curl outward from a disassembling tip. But whether protofilaments can work efficiently via this spring-like mechanism has been unclear. By modifying a previous assay to use recombinant tubulin and feedback-controlled laser trapping, we directly demonstrate the spring-like elasticity of curling protofilaments. Measuring their mechanical work output suggests they carry ~25% of the energy of GTP hydrolysis as bending strain, enabling them to drive movement with efficiency similar to conventional motors. Surprisingly, a β-tubulin mutant that dramatically slows disassembly has no effect on work output, indicating an uncoupling of disassembly speed from protofilament strain. These results show the wave mechanism can make a major contribution to kinetochore motility and establish a direct approach for measuring tubulin mechano-chemistry.
Muscle-tendon interaction and elastic energy usage in human walking
DEFF Research Database (Denmark)
Ishikawa, Masaki; Komi, Paavo V.; Grey, Michael James
2005-01-01
The present study was designed to explore how the interaction between the fascicles and tendinous tissues is involved in storage and utilization of elastic energy during human walking. Eight male subjects walked with a natural cadence (1.4 +/- 0.1 m/s) on a 10-m-long force plate system. In vivo......-stance phase. In contrast, the soleus fascicles were lengthened until the end of the single-stance phase. These findings suggest that the elastic recoil takes place not as a spring-like bouncing but as a catapult action in natural human walking. The interaction between the muscle fascicles and tendinous...
The economic concept of the elasticity and their incidence in the Colombian energy market
International Nuclear Information System (INIS)
Perez Bedoya, Edigson
1996-01-01
The topic that is presented denotes a singular importance mainly for those who have to planning and to project the energetic sector. The Colombian energy basket has been increased, from this perspective and now the development and the taking of decisions cannot manage in isolate form, the reason of the report, more than ever it incorporates the concept of economic elasticity. This is not more than the compass that allows decanting, if the variations of the prices in the energy basket will have (x) or (y) result in the final consumer. The elasticity finally measures the reactions that from the offer and demand of energy can be unchained by a certain stimulus politics in the energy market
International Nuclear Information System (INIS)
Hisnanick, J.J.; Kyer, B.L.
1995-01-01
The role of energy in the production of manufacturing output has been debated extensively in the literature, particularly its relationship with capital and labor. In an attempt to provide some clarification in this debate, a two-step methodology was used. First under the assumption of a five-factor production function specification, we distinguished between electric and non-electric energy and assessed each component's relationship with capital and labor. Second, we calculated both the Allen and price elasticities and constructed 95% confidence intervals around these values. Our approach led to the following conclusions: that the disaggregation of the energy input into electric and non-electric energy is justified; that capital and electric energy and capital and non-electric energy are substitutes, while labor and electric energy and labor and non-electric energy are complements in production; and that capital and energy are substitutes, while labor and energy are complements. (author)
Elastic-plastic potential functionals for rates and increments of stress and strain
International Nuclear Information System (INIS)
Feijoo, R.A.; Zouain, N.
1990-03-01
In this work attention is focused in the derivation of variational formulations of the constutive relationship in the form of conjugate potential functionals from which stress and strain rates are derived as elements of the corresponding sub-differential sets. The main result obtained is a pair of potential functionals. (A.C.A.S.) [pt
Existence of solutions for the anti-plane stress for a new class of “strain-limiting” elastic bodies
Bulí ček, Miroslav; Má lek, Josef; Rajagopal, K. R.; Walton, Jay R.
2015-01-01
© 2015, Springer-Verlag Berlin Heidelberg. The main purpose of this study is to establish the existence of a weak solution to the anti-plane stress problem on V-notch domains for a class of recently proposed new models that could describe elastic materials in which the stress can increase unboundedly while the strain yet remains small. We shall also investigate the qualitative properties of the solution that is established. Although the equations governing the deformation that are being considered share certain similarities with the minimal surface problem, the boundary conditions and the presence of an additional model parameter that appears in the equation and its specific range makes the problem, as well as the result, different from those associated with the minimal surface problem.
Existence of solutions for the anti-plane stress for a new class of “strain-limiting” elastic bodies
Bulíček, Miroslav
2015-04-21
© 2015, Springer-Verlag Berlin Heidelberg. The main purpose of this study is to establish the existence of a weak solution to the anti-plane stress problem on V-notch domains for a class of recently proposed new models that could describe elastic materials in which the stress can increase unboundedly while the strain yet remains small. We shall also investigate the qualitative properties of the solution that is established. Although the equations governing the deformation that are being considered share certain similarities with the minimal surface problem, the boundary conditions and the presence of an additional model parameter that appears in the equation and its specific range makes the problem, as well as the result, different from those associated with the minimal surface problem.
Directory of Open Access Journals (Sweden)
A. Gudmundsson
2012-07-01
Full Text Available Natural hazards associated with volcanic edifices depend partly on how fracture resistant the edifices are, i.e. on their strengths. Observations worldwide indicate that large fluid-driven extension fractures (dikes, inclined sheets, shear fractures (landslides, and mixed-mode fractures (ring dikes and ring faults normally propagate more easily in a basaltic edifice (shield volcano than in a stratovolcano. For example, dike-fed eruptions occur once every few years in many basaltic edifices but once every 10^{2-3} yr in many stratovolcanoes. Large landslides and caldera collapses also appear to be more common in a typical basaltic edifice/shield volcano than in a typical stratovolcano. In contrast to a basaltic edifice, a stratovolcano is composed of mechanically dissimilar rock layers, i.e. layers with mismatching elastic properties (primarily Young's modulus. Elastic mismatch encourages fracture deflection and arrest at contacts and increases the amount of energy needed for a large-scale edifice failure. Fracture-related hazards depend on the potential energy available to propagate the fractures which, in turn, depends on the boundary conditions during fracture propagation. Here there are two possible scenarios: one in which the outer boundary of the volcanic edifice or rift zone does not move during the fracture propagation (constant displacement; the other in which the boundary moves (constant load. In the former, the total potential energy is the strain energy stored in the volcano before fracture formation; in the latter, the total potential energy is the strain energy plus the work done by the forces moving the boundary. Constant-displacement boundary conditions favor small eruptions, landslides, and caldera collapses, whereas constant-load conditions favor comparatively large eruptions, landslides, and collapses. For a typical magma chamber (sill-like with a diameter of 8 km, the strain energy change due to magma-chamber inflation
Fuel demand elasticities for energy and environmental policies: Indian sample survey evidence
International Nuclear Information System (INIS)
Gundimeda, Haripriya; Koehlin, Gunnar
2008-01-01
India has been running large-scale interventions in the energy sector over the last decades. Still, there is a dearth of reliable and readily available price and income elasticities of demand to base these on, especially for domestic use of traditional fuels. This study uses the linear approximate Almost Ideal Demand System (LA-AIDS) using micro data of more than 100,000 households sampled across India. The LA-AIDS model is expanded by specifying the intercept as a linear function of household characteristics. Marshallian and Hicksian price and expenditure elasticities of demand for four main fuels are estimated for both urban and rural areas by different income groups. These can be used to evaluate recent and current energy policies. The results can also be used for energy projections and carbon dioxide simulations given different growth rates for different segments of the Indian population. (author)
Directory of Open Access Journals (Sweden)
Philipp Beckerle
2017-09-01
Full Text Available Variable elastic actuators are very promising for applications in physical human–robot interaction. Besides enabling human safety, such actuators can support energy efficiency, especially if the natural behavior of the system is exploited. In this paper, the power and energy consumption of variable stiffness actuators with serial elasticity is investigated analytically and experimentally. Besides the fundamental mechanics, the influence of friction and electrical losses is discussed. A simple but effective stiffness control method is used to exploit the corresponding knowledge of natural dynamics by tuning the system to antiresonance operation. Despite nonlinear friction effects and additional electrical dynamics, the consideration of the ideal mechanical dynamics is completely sufficient for stiffness control. Simulations and experiments show that this yields a distinct reduction in power and energy consumption, which underlines the suitability of the control strategy.
Utilization of stored elastic energy in leg extensor muscles by men and women.
Komi, P V; Bosco, C
1978-01-01
An alternating cycle of eccentric-concentric contractions in locomotion represents a sequence when storage and utilization of elastic energy takes place. It is possible that this storage capacity and its utilization depends on the imposed stretch loads in activated muscles, and that sex differences may be present in these phenomena. To investigate these assumed differences, subjects from both sexes and of good physical condition performed vertical jumps on the force-platform from the following experimental conditions: squatting jump (SJ) from a static starting position; counter-movement jump (CMJ) from a free standing position and with a preparatory counter-movement; drop jumps (DJ) from the various heights (20 to 100 cm) on to the platform followed immediately by a vertical jump. In all subjects the SJ, in which condition no appreciable storage of elastic energy takes place, produced the lowest height of rise of the whole body center of gravity (C.G.). The stretch load (drop height) influenced the performance so that height of rise of C. of G. increased when the drop height increased from 26 up to 62 cm (males) and from 20 to 50 cm (females). In all jumping conditions the men jumped higher than the women. However, examination of the utilization of elastic energy indicated that in CMJ the female subjects were able to utilize most (congruent to 90%) of the energy produced in the prestretching phase. Similarly, in DJ the overall change in positive energy over SJ condition was higher in women as compared to men. Thus the results suggest that although the leg extensor muscles of the men subjects could sustain much higher stretch loads, the females may be able to utilize a greater portion of the stored elastic energy in jumping activities.
Application of Strain Energy on BIW Mode Optimization
Directory of Open Access Journals (Sweden)
Chang Guangbao
2015-01-01
Full Text Available This paper takes the BIW model as the research object, completes modal analysis, and verifies the finite element model by comparing the simulation results with the test results. In order to improve the frequency of BIW, the weak structure of D pillar is found and then optimized by the method of strain energy, and the frequency of BIW is changed from 28.80Hz to 32.15Hz. Finally, the method of strain energy has great positive effects on modal optimization.
Effect of elastic interphase strains on extinction in aging nimonic type alloys
International Nuclear Information System (INIS)
Gitgarts, M.I.; Ivashin, V.V.
1977-01-01
The effect of νsup(')-phase separation processes on the variation of (3) CuKsub(α) diffraction line integral intensity in KhN67VMTYu alloy ageing has been investigated, the alloy being characterized by various degrees of volumetric inconsistency between the separation phase and matrix. The ageing of KhN67VMTYu alloy, in which the separation of the νsup(')-phase does not cause interphase strains, is not accompanied by abatement of extinction: the diffraction line intensity is practically the same for both aged and tempered specimens
Directory of Open Access Journals (Sweden)
I. K. Badalakha
2009-12-01
Full Text Available The article presents the results of solving several problems of a flat deformation of elastic infinitely long massifs of different width and limited thickness. Various cases of conditions at the massif/base contact. The relationships between stressed and strained states previously suggested by the author, which differ from the generalized Hooke’s law, are used in the solutions.
Directory of Open Access Journals (Sweden)
I. K. Badalakha
2009-02-01
Full Text Available The article shows the result of solving the problem of stress-strain state of an elastic half-space because of the load action that uniformly distributed over the line, with the use of untraditional linear dependence of deformations on stressed state that is different from the generalized Hooke’s law.
Autonomous efficiency improvement or income elasticity of energy demand: Does it matter?
International Nuclear Information System (INIS)
Webster, Mort; Paltsev, Sergey; Reilly, John
2008-01-01
Observations of historical energy consumption, energy prices, and income growth in industrial economies exhibit a trend in improving energy efficiency even when prices are constant or falling. Two alternative explanations of this phenomenon are: a productivity change that uses less energy and a structural change in the economy in response to rising income. It is not possible to distinguish among these from aggregate data, and economic energy models for forecasting emissions simulate one, as an exogenous time trend, or the other, as energy demand elasticity with respect to income, or both processes for projecting energy demand into the future. In this paper, we ask whether and how it matters which process one uses for projecting energy demand and carbon emissions. We compare two versions of the MIT Emissions Prediction and Policy Analysis (EPPA) model, one using a conventional efficiency time trend approach and the other using an income elasticity approach. We demonstrate that while these two versions yield equivalent projections in the near-term, that they diverge in two important ways: long-run projections and under uncertainty in future productivity growth. We suggest that an income dependent approach may be preferable to the exogenous approach
A new impact picture for low and high energy proton-proton elastic scattering
International Nuclear Information System (INIS)
Bourrely, C.; Soffer, J.; Wu, Tai Tsun
1978-05-01
The impact picture that was used several years ago to predict the increase of total and integrated differential cross sections at high energies was improved significantly. The major improvements consist of the following: (1) the dependence of the Pomeron term on the momentum transfer is taken from a modified version of the relation between matter distribution and charge distribution; (2) Regge backgrounds are properly taken into account; and (3) a simple non-trivial form is used for the hadronic matter current in the proton. For proton-proton elastic scattering, the phenomenological differential cross section is in good agreement with the experimental data in the laboratory momentum range of 14 GeV/c to 2000 GeV/c, and is predicted for ISABELLE energy. Because of the third improvement, predictions are obtained for both polarization and R parameters for proton-proton elastic scattering
Excitation function of elastic scattering on 12C + 4He system, at low energies
International Nuclear Information System (INIS)
Perez-Torres, R.; Aguilera, E. F.; Martinez-Quiroz, E.; Murillo, G.; Belyaeva, T. L.; Maldonado-Velazquez, M.
2011-01-01
Interactions in the 12 C + 4 He system are of great interest in astrophysics and to help determine the relative abundances of elements in stars, at the end of helium burning [1, 2]. The Instituto Nacional de Investigaciones Nucleares (ININ) in Mexico, have made measurements of elastic scattering for this system, using the inverse kinematics method with thick white gas [3, 4], for E CM (0.5 - 4 MeV) θ CM = 180 o . In this work we obtain excitation functions of elastic scattering of 12 C + 4 He system with angular and energy dependence; E CM = 0.5 - 4 MeV and θ CM 100 o -170 o .Using inverse kinematics method with thick white gas and energy loss tables. (Author)
Thorpe, Chavaunne T; Godinho, Marta S C; Riley, Graham P; Birch, Helen L; Clegg, Peter D; Screen, Hazel R C
2015-12-01
While the predominant function of all tendons is to transfer force from muscle to bone and position the limbs, some tendons additionally function as energy stores, reducing the cost of locomotion. Energy storing tendons experience extremely high strains and need to be able to recoil efficiently for maximum energy storage and return. In the equine forelimb, the energy storing superficial digital flexor tendon (SDFT) has much higher failure strains than the positional common digital extensor tendon (CDET). However, we have previously shown that this is not due to differences in the properties of the SDFT and CDET fascicles (the largest tendon subunits). Instead, there is a greater capacity for interfascicular sliding in the SDFT which facilitates the greater extensions in this particular tendon (Thorpe et al., 2012). In the current study, we exposed fascicles and interfascicular matrix (IFM) from the SDFT and CDET to cyclic loading followed by a test to failure. The results show that IFM mechanical behaviour is not a result of irreversible deformation, but the IFM is able to withstand cyclic loading, and is more elastic in the SDFT than in the CDET. We also assessed the effect of ageing on IFM properties, demonstrating that the IFM is less able to resist repetitive loading as it ages, becoming stiffer with increasing age in the SDFT. These results provide further indications that the IFM is important for efficient function in energy storing tendons, and age-related alterations to the IFM may compromise function and predispose older tendons to injury. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.
The EDDA experiment: proton-proton elastic scattering excitation functions at intermediate energies
International Nuclear Information System (INIS)
Hinterberher, F.
1996-01-01
The EDDA experiment is designed to provide a high precision measurement of proton-proton elastic scattering excitation functions ranging from 0.5 to 2.5 GeV of (lab) incident kinetic energy. It is an internal target experiment utilizing the proton beam of the cooler synchrotron COSY operated by KFA Juelich. The excitation functions are measured during the acceleration ramp of COSY. (author)
Energy decay for solutions to semilinear systems of elastic waves in exterior domains
Directory of Open Access Journals (Sweden)
Marcio V. Ferreira
2006-05-01
Full Text Available We consider the dynamical system of elasticity in the exterior of a bounded open domain in 3-D with smooth boundary. We prove that under the effect of "weak" dissipation, the total energy decays at a uniform rate as $t o +infty$, provided the initial data is "small" at infinity. No assumptions on the geometry of the obstacle are required. The results are then applied to a semilinear problem proving global existence and decay for small initial data.
Dipole pomeron and. pi. /sup -/p elastic scattering at high energies
Energy Technology Data Exchange (ETDEWEB)
Fazal-E-Aleem (Panjab Univ., Lahore (Pakistan). Physics Dept.)
1982-10-16
The differential cross-sections for high-energy ..pi../sup -/p elastic scattering showing structure near -t=4 (GeV/c)/sup 2/ for psub(L)=50 and 200 GeV/c together with total cross-sections for 50<=psub(L)<=370 GeV/c, and with -t extending up to 11 (GeV/c)/sup 2/ have been fitted by using a dipole pomeron model.
Coupled modeling and simulation of electro-elastic materials at large strains
Possart, Gunnar; Steinmann, Paul; Vu, Duc-Khoi
2006-03-01
In the recent years various novel materials have been developed that respond to the application of electrical loading by large strains. An example is the class of so-called electro-active polymers (EAP). Certainly these materials are technologically very interesting, e.g. for the design of actuators in mechatronics or in the area of artificial tissues. This work focuses on the phenomenological modeling of such materials within the setting of continuum-electro-dynamics specialized to the case of electro-hyperelastostatics and the corresponding computational setting. Thereby a highly nonlinear coupled problem for the deformation and the electric potential has to be considered. The finite element method is applied to solve the underlying equations numerically and some exemplary applications are presented.
International Nuclear Information System (INIS)
Mitrofanov, Yu.P.; Peterlechner, M.; Binkowski, I.; Zadorozhnyy, M.Yu.; Golovin, I.S.; Divinski, S.V.; Wilde, G.
2015-01-01
The effects of deformation and subsequent heat treatment on the low-temperature heat capacity, enthalpy relaxation rate and mechanical losses of two Pd–Ni–P-based bulk metallic glasses of slightly different compositions and different thermal stabilities have been investigated. It was found that the crystallization temperatures decreased significantly with imposed strain and the effect was more pronounced for the alloy with a higher thermal stability. The boson heat capacity peak increases with increasing strain in both alloys. However, after annealing treatments above room temperature, it relaxes to a lower enthalpy state as compared to that of the as-quenched state for the alloy with a lower thermal stability. The existence of two counteracting processes that might be related to different shear band structures within one homogeneously deformed sample is suggested. These results agree with the internal friction data, which indicate different regimes of mechanical damping as a function of the strain amplitude, while the critical amplitude of a transition between the regimes depends on the imposed strain. The results are interpreted within the energy landscape approach and advocate that the composition-dependent local atomic configurations affect significantly the response of the glass to an applied strain
Spatial-structural interaction and strain energy structural optimisation
Hofmeyer, H.; Davila Delgado, J.M.; Borrmann, A.; Geyer, P.; Rafiq, Y.; Wilde, de P.
2012-01-01
A research engine iteratively transforms spatial designs into structural designs and vice versa. Furthermore, spatial and structural designs are optimised. It is suggested to optimise a structural design by evaluating the strain energy of its elements and by then removing, adding, or changing the
Investigation of {sup 17}F+p elastic scattering at near-barrier energies
Energy Technology Data Exchange (ETDEWEB)
El-Azab Farid, M. [Assiut University, Physics Department, Assiut (Egypt); Ibraheem, Awad A. [Al-Azhar University, Physics Department, Assiut (Egypt); King Khalid University, Physics Department, Abha (Saudi Arabia); Al-Hajjaji, Arwa S. [Taiz University, Physics Department, Taiz (Yemen)
2015-10-15
The {sup 17}F +p elastic scattering at two near-barrier energies of 3.5 and 4.3 MeV/nucleon, have been analyzed in the framework of the single folding approach. The folded potentials are constructed by folding the density-dependent (DDM3Y) effective nucleon-nucleon interaction over the nuclear density of the one-proton halo nucleus {sup 17}F. Two versions of the density are considered. In addition, two versions of the one-nucleon knock-on exchange potentials are introduced to construct the real microscopic potentials. The derived potentials supplemented by phenomenological Woods-Saxon imaginary and spin-orbit potentials produced excellent description of the differential elastic scattering cross sections at the higher energy without need to introduce any renormalization. At the lower energy, however, in order to successfully reproduce the data, it is necessary to reduce the strength of the constructed real DDM3Y potential by about 25% of its original value. Furthermore, good agreement with data is obtained using the extracted microscopic DDM3Y potentials for both real and imaginary parts. Moreover, the interesting notch test is applied to investigate the sensitivity of the elastic scattering cross section to the radial distribution of the constructed microscopic potentials. The extracted reaction (absorption) cross sections are, also, investigated. (orig.)
Investigation of 17F+p elastic scattering at near-barrier energies
International Nuclear Information System (INIS)
El-Azab Farid, M.; Ibraheem, Awad A.; Al-Hajjaji, Arwa S.
2015-01-01
The 17 F +p elastic scattering at two near-barrier energies of 3.5 and 4.3 MeV/nucleon, have been analyzed in the framework of the single folding approach. The folded potentials are constructed by folding the density-dependent (DDM3Y) effective nucleon-nucleon interaction over the nuclear density of the one-proton halo nucleus 17 F. Two versions of the density are considered. In addition, two versions of the one-nucleon knock-on exchange potentials are introduced to construct the real microscopic potentials. The derived potentials supplemented by phenomenological Woods-Saxon imaginary and spin-orbit potentials produced excellent description of the differential elastic scattering cross sections at the higher energy without need to introduce any renormalization. At the lower energy, however, in order to successfully reproduce the data, it is necessary to reduce the strength of the constructed real DDM3Y potential by about 25% of its original value. Furthermore, good agreement with data is obtained using the extracted microscopic DDM3Y potentials for both real and imaginary parts. Moreover, the interesting notch test is applied to investigate the sensitivity of the elastic scattering cross section to the radial distribution of the constructed microscopic potentials. The extracted reaction (absorption) cross sections are, also, investigated. (orig.)
Elastic strain engineering of quantum dot excitonic emission in nanomembranes and optical resonators
Energy Technology Data Exchange (ETDEWEB)
Ding, Fei; Plumhof, Johannes; Rastelli, Armando; Schmidt, Oliver [Institute for Integrative Nanosciences, IFW Dresden (Germany); Singh, Ranber; Zander, Tim; Bester, Gabriel [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)
2010-07-01
We study the effect of an external biaxial stress on the light emission of single InGaAs/GaAs(001) quantum dots (QD) embedded in a 200 nm-thick-membrane. Reversible and bi-directional spectral tuning of QD excitonic emission is demonstrated via a simple electro-mechanical device. The most intriguing finding is that biaxial strain is a reliable tool to engineer the QD electronic structure and reach color coincidence between exciton and biexciton emission, providing a vital prerequisite for the generation of polarization entangled photon pairs through a time reordering strategy. The physical origin of this new phenomenon is discussed based on the empirical pseudopotential calculations. With similar technique we study the effect of biaxial stress on single QDs embedded in microring resonators. The microrings can be reversibly stretched or squeezed, resulting in a controllable engineering of both QD emissions and optical modes. Our results open up a new tuning strategy to study cQED with semiconductor quantum dots.
Chapman, Martin Colby
1998-12-01
The design earthquake selection problem is fundamentally probabilistic. Disaggregation of a probabilistic model of the seismic hazard offers a rational and objective approach that can identify the most likely earthquake scenario(s) contributing to hazard. An ensemble of time series can be selected on the basis of the modal earthquakes derived from the disaggregation. This gives a useful time-domain realization of the seismic hazard, to the extent that a single motion parameter captures the important time-domain characteristics. A possible limitation to this approach arises because most currently available motion prediction models for peak ground motion or oscillator response are essentially independent of duration, and modal events derived using the peak motions for the analysis may not represent the optimal characterization of the hazard. The elastic input energy spectrum is an alternative to the elastic response spectrum for these types of analyses. The input energy combines the elements of amplitude and duration into a single parameter description of the ground motion that can be readily incorporated into standard probabilistic seismic hazard analysis methodology. This use of the elastic input energy spectrum is examined. Regression analysis is performed using strong motion data from Western North America and consistent data processing procedures for both the absolute input energy equivalent velocity, (Vsbea), and the elastic pseudo-relative velocity response (PSV) in the frequency range 0.5 to 10 Hz. The results show that the two parameters can be successfully fit with identical functional forms. The dependence of Vsbea and PSV upon (NEHRP) site classification is virtually identical. The variance of Vsbea is uniformly less than that of PSV, indicating that Vsbea can be predicted with slightly less uncertainty as a function of magnitude, distance and site classification. The effects of site class are important at frequencies less than a few Hertz. The regression
Local nuclear slope and curvature in high energy pp and pp-bar elastic scattering
Energy Technology Data Exchange (ETDEWEB)
Desgrolard, P. [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Kontros, J.; Lengyel, A.I. [Inst. of Electron Physics, Uzhgorod (Ukraine); Martynov, E.S. [National Academy of Sciences of Ukraine, Kiev (Ukraine). Bogolyubov Inst. for Theoretical Physics
1997-05-01
The local nuclear slope is reconstructed from the experimental angular distributions with a procedure that uses overlapping t-bins, for an energy that ranges from the ISR to the Sp-bar pS and the Tevatron. Predictions of several models of (p-bar,p) elastic scattering at high energy are tested. Only a model with two-components Pomeron and Odderon gives a satisfactory agreement with the (non fitted) slope data. The extreme sensitivity of the local nuclear curvature with the choice for a Pomeron model is emphasized. (author). 30 refs.
Differential cross sections for the elastic scattering of intermediate energy electrons from sodium
International Nuclear Information System (INIS)
Teubner, P.J.O.; Buckner, S.J.; Noble, C.J.
1977-11-01
Differential cross sections for the elastic scattering of electrons from sodium have been measured with high angular resolution for incident energies of 54.4, 75, 100 and 150 eV and over an angular range of 12 0 to 140 0 . The experimental data are compared with calculations based on the First Born approximation, the Glauber approximation and a close coupling impact parameter calculation. Calculations have been carried out for an optical model using the prescription of Vanderpoorten for localizing the absorptive part of the potential. Of the theoretical calculations the optical model is found to best reproduce the general features of the cross section at all energies. (Author)
Limitations to depth resolution in high-energy, heavy-ion elastic recoil detection analysis
International Nuclear Information System (INIS)
Elliman, R.G.; Palmer, G.R.; Ophel, T.R.; Timmers, H.
1998-01-01
The depth resolution of heavy-ion elastic recoil detection analysis was examined for Al and Co thin films ranging in thickness from 100 to 400 nm. Measurements were performed with 154 MeV Au ions as the incident beam, and recoils were detected using a gas ionisation detector. Energy spectra were extracted for the Al and Co recoils and the depth resolution determined as a function of film thickness from the width of the high- and low- energy edges. These results were compared with theoretical estimates calculated using the computer program DEPTH. (authors)
(16) {C}16C-elastic scattering examined using several models at different energies
El-hammamy, M. N.; Attia, A.
2018-05-01
In the present paper, the first results concerning the theoretical analysis of the ^{16}C + p reaction by investigating two elastic scattering angular distributions measured at high energy compared to low energy for this system are reported. Several models for the real part of the nuclear potential are tested within the optical model formalism. The imaginary potential has a Woods-Saxon shape with three free parameters. Two types of density distribution and three different cluster structures for ^{16}C are assumed in the analysis. The results are compared with each other as well as with the experimental data to give evidence of the importance of these studied items.
Energy-Dependent microscopic optical potential for p+{sup 9}Be elastic scattering
Energy Technology Data Exchange (ETDEWEB)
Maridi, H. M., E-mail: h.maridi@gmail.com [Physics Department, Faculty of Science, Cairo University, Giza 12613 (Egypt); Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen); Farag, M. Y. H., E-mail: yehiafarag@cu.edu.eg; Esmael, E. H. [Physics Department, Faculty of Applied Science, Taiz University, Taiz (Yemen)
2016-06-10
The p+{sup 9}Be elastic scattering at an energy range up to 200 MeV/nucleon is analyzed using the single-folding model. The density- and isospin-dependent M3Y-Paris nucleon-nucleon (NN) interaction is used for the real part and the NN-scattering amplitude of the high-energy approximation for the imaginary one. The analysis reveals that the cross-section data are reproduced well at energies up to 100 MeV/nucleon by use of the partial-wave expansion. For higher energies, the eikonal approximation give results better than the partial-wave expansion calculations. The volume integrals of the optical-potential parts have systematic energy dependencies, and they are parameterized in empirical formulas.
Emission and elastic strain in InGaAs/GaAs quantum wells with embedded InAs quantum dots
Energy Technology Data Exchange (ETDEWEB)
Vega-Macotela, L.G.; Polupan, G. [ESIME - Instituto Politecnico Nacional, Mexico D.F. 07738 (Mexico); Shcherbyna, Ye. [National Technical University-' ' KPI' ' , Kiev 03057 (Ukraine)
2012-07-15
Photoluminescence (PL) spectra have been studied in the symmetric GaAs/In{sub 0.15}Ga{sub 0.85}As/GaAs quantum wells (QWs) with embedded InAs quantum dots (QDs), grown at different temperatures from the range 470-535 C. The increase of QD growth temperature is accompanied by decreasing the QD surface density and the enlargement of QD lateral diameters. Simultaneously the variation of the PL intensity and PL peak positions none monotonously have been detected. To understand the reason of the variation of PL intensity and peak positions the PL temperature dependences and the X-ray diffraction (XRD) at low angles (1.75-1.92 ) have been studied. The fitting procedure is applied to analysis the temperature shift of PL peak positions. Fitting has been done on the base of empirical expression for the band gap shrinkage that uses the Einstein temperature parameter. The character non monotonous for the Ga/In inter diffusion versus QD growth temperatures has been revealed. The XRD study has detected the high intensity peaks that corresponds to the diffraction of X-ray beam from the (311) crystal planes in GaAs QWs. The position of XRD peaks in the structures with QD grown at 490-510 C is very close to the angles related to the diffraction from (311) planes in the bulk GaAs. In QD structures with QD grown at 470 and 525-535 C the (311) XRD peaks shift to the higher diffraction angles that testifies on the essential compressive strains in these structures. The reason of the variation non monotonously of elastic strain versus QD densities has been discussed (copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)
International Nuclear Information System (INIS)
Ledbetter, H.M.
1983-01-01
This chapter investigates the following five aspects of engineering-material solid-state elastic constants: general properties, interrelationships, relationships to other physical properties, changes during cooling from ambient to near-zero temperature, and near-zero-temperature behavior. Topics considered include compressibility, bulk modulus, Young's modulus, shear modulus, Poisson's ratio, Hooke's law, elastic-constant measuring methods, thermodynamic potentials, higher-order energy terms, specific heat, thermal expansivity, magnetic materials, structural phase transitions, polymers, composites, textured aggregates, and other-phenomena correlations. Some of the conclusions concerning polycrystalline elastic properties and their temperature dependence are: elastic constants are physical, not mechanical, properties which relate thermodynamically to other physical properties such as specific heat and thermal expansivity; elastic constants at low temperatures are nearly temperature independent, as required by the third law of thermodynamics; and elastic constants can be used to study directional properties of materials, such as textured aggregates and composites
International Nuclear Information System (INIS)
Kawano, Toshihiko; Talou, Patrick
2012-01-01
The statistical theories - the Hauser-Feshbach model with the width fluctuation correction - play a central role in studying nuclear reactions in the fast energy region, hence the statistical model codes are essential for the nuclear data evaluations nowadays. In this paper, we revisit issues regarding the statistical model calculations in the fast energy range, such as the inclusion of the direct channels, and the energy averaged cross sections using different statistical assumptions. Although they have been discussed for a long time, we need more precise quantitative investigations to understand uncertainties coming from the models deficiencies in the fast energy range. For example, the partition of compound formation cross section into the elastic and inelastic channels depends on the elastic enhancement factor calculated from the statistical models. In addition, unitarity of S-matrix constrains this partition when the direct reactions are involved. Practically some simple assumptions, which many nuclear reaction model codes adopt, may work reasonably for the nuclear data evaluations. However, the uncertainties on the evaluated cross sections cannot go lower than the model uncertainty itself. We perform numerical simulations by generating the resonances using the R-matrix theory, and compare the energy (ensemble) averaged cross sections with the statistical theories, such as the theories of Moldauer, HRTW (Hofmann, Richert, Tepel, and Weidenmueller), KKM (Kawai-Kerman-McVoy), and GOE (Gaussian orthogonal ensemble).
International Nuclear Information System (INIS)
Kamaya, Masayuki
2012-01-01
Although the plastic strain induced in materials increases the mechanical strength, it may reduce the fracture toughness. In this study, the change in fracture toughness of SM490 carbon steel due to pre-straining was investigated using a stress-based criterion for ductile crack initiation. The specimens with blunt notch of various radiuses were used in addition to those with conventional fatigue pre-cracking. The degree of applied plastic strain was 5%, 10% or 20%. The fracture toughness was largest when the induced plastic strain was 5%, although it decreased for the plastic strains of 10% and 20%. The stress and strain distributions near the crack tip of fracture toughness test specimens was investigated by elastic-plastic finite element analyses using a well-correlated stress-strain curve for large strain. It was shown that the critical condition at the onset of the ductile crack was better correlated with the equivalent stress than the plastic strain at the crack tip. By using the stress-based criterion, which was represented by the equivalent stress and stress triaxiality, the change in the fracture toughness due to pre-straining could be reasonably explained. Based on these results, it was concluded that the stress-based criterion should be used for predicting the ductile crack initiation. (author)
Energy Technology Data Exchange (ETDEWEB)
Sahmani, Saeid; Bahrami, Mohsen [Amirkabir University of Technology, Tehran (Iran, Islamic Republic of)
2015-01-15
In the current paper, dynamic stability analysis of microbeams subjected to piezoelectric voltage is presented in which the microbeam is integrated with piezoelectric layers on the lower and upper surfaces. Both of the flutter and divergence instabilities of microbeams with clamped-clamped and clamped-free boundary conditions are predicted corresponding to various values of applied voltage. To take size effect into account, the classical Timoshenko beam theory in conjunction with strain gradient elasticity theory is utilized to develop nonclassical beam model containing three additional internal length scale parameters. By using Hamilton's principle, the higher-order governing differential equations and associated boundary conditions are derived. Afterward, generalized differential quadrature method is employed to discretize the size-dependent governing differential equations along with clamped-clamped and clamped-free end supports. The critical piezoelectric voltages corresponding to various values dimensionless length scale parameter are evaluated and compared with those predicted by the classical beam theory. It is revealed that in the case of clamped-free boundary conditions, the both of flutter and divergence instabilities occur. However, for the clamped-clamped microbeams, only divergence instability takes place.
Phason elasticity and surface roughening
International Nuclear Information System (INIS)
Tang Leihan; Jaric, M.V.
1990-01-01
The phason elasticity of two-dimensional (2D) equilibrium quasicrystals is discussed in analogy with surface roughening phenomena. Taking a Penrose tiling model as an example, we show that the phason elastic energy is linear in the phason strain at zero temperature (T = 0), but becomes quadratic at any T > 0 and sufficiently small strain. Heuristic and real-space renormalization group arguments are given for the thermal roughening of the hyper-surface which represents quasicrystal tiling. Monte Carlo method is applied to illustrate the logarithmically diverging phason fluctuations and power-law diffraction intensities at T > 0. For three-dimensional systems, we present arguments which suggest a finite temperature transition between two quasicrystal phases, characterized by linear and quadratic phason elastic energy, respectively. (author). 17 refs, 12 figs
Energy Technology Data Exchange (ETDEWEB)
Galarraga, Ibon, E-mail: ibon.galarraga@bc3research.org; Gonzalez-Eguino, Mikel, E-mail: mikel.gonzalez@bc3research.org; Markandya, Anil, E-mail: anil.markandya@bc3research.org
2011-12-15
This article proposes a combined approach for estimating willingness to pay for the attributes represented by energy efficiency labels and providing reliable price elasticities of demand (own and cross) for close substitutes (e.g. those with low energy efficiency and those with higher energy efficiency). This is done by using the results of the hedonic approach together with the Quantity Based Demand System (QBDS) model. The elasticity results obtained with the latter are then compared with those simulated using the Linear Almost Ideal Demand System (LA/AIDS). The methodology is applied to the dishwasher market in Spain: it is found that 15.6% of the final price is actually paid for the energy efficiency attribute. This accounts for about Euro 80 of the average market price. The elasticity results confirm that energy efficient appliances are more price elastic than regular ones. - Highlights: > The article shows a combined approach for estimating willingness to pay for energy efficiency labels and price elasticities. > The results of the hedonic approach is used together with the Quantity Based Demand System (QBDS) model. > The elasticity results are compared with those simulated using the Linear Almost Ideal Demand System (LA/AIDS). > The methodology is applied to the dishwasher market in Spain.
Forward elastic scattering and total cross-section at very high energies
International Nuclear Information System (INIS)
Castaldi, R.
1985-01-01
The successful cooling technique of antiproton beams at CERN has recently allowed the acceleration of proton and antiproton bunches simultaneously circulating in opposite directions in the SPS. Hadron-hadron collisions could so be produced at a centre-of-mass energy one order of magnitude higher than previously available, thus opening a new wide range of energies to experimentation. This technique also made it possible to replace one of the two proton beams in the ISR by a beam of antiprotons, allowing a direct precise comparison, by the same detectors, of pp and anti pp processes at the same energies. The recent results are summarized of the forward elastic scattering and total cross-section in this new energy domain. (Mori, K.)
Han PHOUMIN; Shigeru KIMURA
2014-01-01
This study uses time series data of selected ASEAN and East Asia countries to investigate the patterns of price and income elasticity of energy demand. Applying a dynamic log-linear energy demand model, both short-run and long-run price and income elasticities were estimated by country. The study uses three types of dependent variable “energy demand” such as total primary energy consumption (TPES), total final energy consumption (TFEC) and total final oil consumption (TFOC) to regress on its ...
Elastic scattering of polarized protons from 3He at intermediate energies
International Nuclear Information System (INIS)
Hasell, D.K.; Bracco, A.; Gubler, H.P.
1982-09-01
Using the polarized proton beam facility of the TRIUMF cyclotron, differential cross sections and analyzing powers have been measured in the angular range 20 0 - 150 0 c.m. for proton elastic scattering from 3 He at incident proton energies of 200, 300, 415 and 515 MeV. The differential cross sections exhibit a minimum at t = -0.33 (GeV/c) 2 which becomes more pronounced with increasing energy. There is evidence for the onset of a second minimum corresponding to the interference between double and triple scattering amplitudes. Large analyzing powers are observed at the lower energies. The data from the present analysis, together with data obtained from the literature in the energy range 100-1000 MeV, have been analyzed within the framework of the Glauber multiple scattering formalism. Nucleon-nucleon scattering parameters were taken from a global phase shift analysis of nucleon-nucleon elastic scattering data. Reasonable agreement with the data is obtained
Energy and target dependence of projectile breakup effect in the elastic scattering of 6Li
International Nuclear Information System (INIS)
Sakuragi, Y.
1986-03-01
Over the wide range of incident energy (E lab = 40 ∼ 170 MeV) and target mass number (A = 12 ∼ 208), projectile breakup effects in the elastic scattering of 6 Li have been investigated with a microscopic coupled-channel method. The coupling to the 6 Li → α + d breakup process is treated with the method of coupled discretized continuum channels (CDCC). 6 Li-target interactions are provided by the folding of the M3Y effective nucleon-nucleon potential with nucleon densities of colliding nuclei. The calculation well reproduces the observed elastic scattering for all the targets and incident energies without any renormalization in the real folding potentials. The breakup effect is found to depend little on the energy and target, which is confirmed by calculating the dynamical polarization potentials induced by the coupling to the breakup process. Almost irrespectively of energy and target, the potential has a repulsive real part with strength of about 40 % of the folding potential in addition to a negligible imaginary part, which explains well the empirical reduction factor of the double-folding model. Discussions are made on the origin of repulsive nature of the breakup effect. (author)
Measurement of the elastic, total and diffraction cross sections at tevatron energies
International Nuclear Information System (INIS)
Belforte, S.
1993-11-01
The CDF collaboration has measured the differential elastic cross section dσ el /dt, the single diffraction dissociation double differential cross section d 2 σ sd /dM 2 dt and the total inelastic cross section for antiproton-proton collisions at center of mass energies √s = 546 and 1,800 GeV. Data for this measurement have been collected in short dedicated runs during the 1988--1989 data taking period of CDF. The elastic scattering slope is 15.28 ± 0.58 (16.98 ± 0.25) GeV -2 at √s = 546 (1,800) GeV. Using the luminosity independent method (1 + ρ 2 )σ T is measured to be 62.64 ± 0.95 (81.83 ± 2.29) mb at √s = 546 (1,800) GeV. Assuming ρ = 0.15 the elastic, total and single diffraction cross sections are σ el = 12.87 ± 0.30, σ T = 61.26 ± 0.93 and σ sd = 7.89 ± 0.33 mb (σ el = 19.70 ± 0.85, σ T = 80.03 ± 2.24 and σ sd = 9.46 ± 0.44 mb) at √s = 546 (1,800) GeV
Energy Technology Data Exchange (ETDEWEB)
Bauer, Fabian; Römer, Ulrich, E-mail: ulrich.roemer@kit.edu; Fidlin, Alexander; Seemann, Wolfgang [Institute of Engineering Mechanics, Karlsruhe Institute of Technology (Germany)
2016-11-15
This paper presents a method to optimize the energy efficiency of walking bipedal robots by more than 80 % in a speed range from 0.3 to 2.3 m/s using elastic couplings—mechanical springs with movement speed independent parameters. The considered planar robot consists of a trunk, two two-segmented legs, two actuators in the hip joints, two actuators in the knee joints and an elastic coupling between the shanks. It is modeled as underactuated system to make use of its natural dynamics and feedback controlled via input–output linearization. A numerical optimization of the joint angle trajectories as well as the elastic couplings is performed to minimize the average energy expenditure over the whole speed range. The elastic couplings increase the swing leg motion’s natural frequency thus making smaller steps more efficient which reduce the impact loss at the touchdown of the swing leg. The process of energy turnover is investigated in detail for the robot with and without elastic coupling between the shanks. Furthermore, the influences of the elastic couplings’ topology and of joint friction are analyzed. It is shown that the optimization of the robot’s motion and elastic coupling towards energy efficiency leads to a slightly slower convergence rate of the controller, yet no loss of stability, but a lower sensitivity with respect to disturbances. The optimal elastic coupling discovered via numerical optimization is a linear torsion spring with transmissions between the shanks. A design proposal for this elastic coupling—which does not affect the robot’s trunk and parallel shank motion and can be used to enhance an existing robot—is given for planar as well as spatial robots.
Elastic Scattering Of 6,7Li+80Se At Near And Above Barrier Energies
International Nuclear Information System (INIS)
Fimiani, L.; Marti, G. V.; Capurro, O. A.; Barbara, E. de; Testoni, J. E.; Zalazar, L.; Arazi, A.; Cardona, M. A.; Carnelli, P.; Figueira, J. M.; Hojman, D.; Martinez Heimann, D.; Negri, A. E.; Pacheco, A. J.; Fernandez Niello, J. O.
2010-01-01
In this work we propose to study the elastic scattering of the weakly bound projectiles 6,7 Li on an intermediate mass target 80 Se. From the experimental results presented here, precise angular distributions at energies below, around and above the nominal Coulomb barriers of the systems were obtained. The final goal of our work is to determine the characteristic parameters of the optical potential and use them to address the question of whether the usual threshold anomaly or the breakup threshold anomaly are present or not in these systems.
11. international conference on elastic and diffractive scattering: towards high energy frontiers
Energy Technology Data Exchange (ETDEWEB)
NONE
2005-07-01
This conference is held every 2 years. Every time these conferences on elastic and diffractive scattering adapt their content to the most recent experimental and theoretical results concerning not only quantum chromodynamics (QCD) but also other fields of particle physics where diffractive physics is present. This year, besides classical themes such as: -) forward scattering, -) total cross-sections, -) real parts, and -) pomeron and odderon, the participants have addressed many other subjects such as: -) LHC physics, -) non-perturbative approaches to high-energy scattering, -) the dipole model, -) small-x evolution, -) hard diffraction in QCD, -) nuclear shadowing, -) diffractive Higgs studies, -) spin effects, -) 4-quarks and 5-quarks, or -) B-physics.
11. international conference on elastic and diffractive scattering: towards high energy frontiers
International Nuclear Information System (INIS)
2005-01-01
This conference is held every 2 years. Every time these conferences on elastic and diffractive scattering adapt their content to the most recent experimental and theoretical results concerning not only quantum chromodynamics (QCD) but also other fields of particle physics where diffractive physics is present. This year, besides classical themes such as: -) forward scattering, -) total cross-sections, -) real parts, and -) pomeron and odderon, the participants have addressed many other subjects such as: -) LHC physics, -) non-perturbative approaches to high-energy scattering, -) the dipole model, -) small-x evolution, -) hard diffraction in QCD, -) nuclear shadowing, -) diffractive Higgs studies, -) spin effects, -) 4-quarks and 5-quarks, or -) B-physics
Study of 40Ca-40Ca elastic scattering at intermediate energy
International Nuclear Information System (INIS)
Kumar, Ashok; Srivastava, B.B.
1980-01-01
The differential cross sections for 40 Ca- 40 Ca elastic scattering have been calculated at laboratory incident energy of 240 MeV using a sharp cut off of the partial waves below a critical angular momentum, 1sub(c)' to account for absorption. The effective 40 Ca- 40 Ca potential is taken to be the sum of a real nuclear potential and the Coulomb potential. The calculated differential cross sections which are in fair agreement with the experimental data are presented and discussed. (author)
A new description of high energy antiproton (proton)-proton elastic scattering
International Nuclear Information System (INIS)
Barshay, S.; Technion-Israel Inst. of Tech., Haifa. Dept. of Physics); Goldberg, J.
1987-01-01
We develop a generalization of the geometric picture for high-energy antiproton (proton)-proton elastic scattering. The eikonal at each impact parameter is considered to have fluctuations about an average value, and is thus characterized by a distribution. A connection to parton branching is made through the specific form of the distribution function for the eikonal. A unified physical theory with significant fluctuations accurately describes the anti p(p)-p data at both √s = 546 GeV and 53 GeV. The fluctuation parameter is remarkably well given by that directly observed in multiparticle production. (orig.)
New description of high energy antiproton (proton)-proton elastic scattering
Energy Technology Data Exchange (ETDEWEB)
Barshay, S; Goldberg, J
1987-10-15
We develop a generalization of the geometric picture for high-energy antiproton (proton)-proton elastic scattering. The eikonal at each impact parameter is considered to have fluctuations about an average value, and is thus characterized by a distribution. A connection to parton branching is made through the specific form of the distribution function for the eikonal. A unified physical theory with significant fluctuations accurately describes the anti p(p)-p data at both ..sqrt..s = 546 GeV and 53 GeV. The fluctuation parameter is remarkably well given by that directly observed in multiparticle production.
Li, Jun; Zhang, Song Bin; Ye, Bang Jiao; Wang, Jian Guo; Janev, R. K.
2017-09-01
Low-energy electron elastic scattering and impact ionization with hydrogenlike helium in Debye plasmas have been investigated by employing the exterior complex scaling method. The interactions between charged particles in the plasmas have been represented by Debye-Hückel potentials. The 1 s -1 s elastic collision strengths below the n =2 excitation threshold of He+ dominated by resonance structures are calculated for different screening lengths. As the screening strength increases, the resonance peaks studied [2(1,0) 2 +1Se,3Po,1De , and 2(0,1) 2 +1Po] exhibit blueshifts and then redshifts with a further increase of the screening strength, which results in dramatic changes of the collision strengths. It is found that these dynamic variation features of the resonances are related to the changes of energy levels of He+ in the screened potential and geometric configurations of resonances. Triple-differential-ionization cross sections in coplanar geometries at 6-Ry incident electron energy are also reported, significant changes are observed with varying screening length.
International Nuclear Information System (INIS)
Dou, L.; Kauppila, W.E.; Kwan, C.K.; Stein, T.S.
1993-01-01
We have measured absolute values of elastic differential cross sections (DCS's) for positron (e + ) scattering by argon (8.7-300 eV), krypton (6.7-400 eV), and also neon (13.6-400 eV) using a crossed-beam experimental setup. When the DCS's are plotted at fixed scattering angles of 30 degrees, 60 degrees, 90 degrees, and 120 degrees versus energy it has been found that well-defined resonance-like structures were found at an energy of 55-60 eV for argon and at 25 and 200 eV for krypton, with a broader structure found between 100-200 eV for neon. These observed resonance-like structures are unusual because they occur at energies well above the known inelastic thresholds for these atoms. They may represent examples of open-quotes coupled channel shape resonancesclose quotes, first predicted by Higgins and Burke for e + -H scattering in the vicinity of 36 eV (width ∼ 4 eV), which occurs only when both the elastic and positronium formation scattering channels are considered together. A more recent e + -H calculation by Hewitt et al. supports the Higgins and Burke prediction. These predictions and the present observations suggest the existence of a new type of atomic scattering resonance
Li Ma; Rong Zhou; Yun-Zhu Li
2017-01-01
Objective: To study the correlation between the ultrasonic elastic strain ratio of thyroid cancer and the malignant biological characteristics of cancer cells in the lesions. Methods: A total of 90 patients with thyroid cancer who accepted surgical treatment in our hospital between March 2015 and September 2016 were selected as the observation group, and 50 patients who received surgery in our hospital during the same period and were with clear pathological diagnosis of thyroid...
Experimental studies and microscopic analysis of the elastic scattering of low energy nucleons
International Nuclear Information System (INIS)
Tarrats-Saugnac, Annie.
1982-05-01
Data on the elastic scattering of low energy nucleons (between 20 and 40 MeV) by nuclei distributed throughout the entire mass table are examined in the framework of a microscopic approach. Two major problems occur at these low energies which do not occur at higher energies: the Pauli principle limits the interaction possibilities of projectiles with bound nucleons in the nucleus; it is not possible to neglect the antisymmetrization between projectiles and nucleon targets resulting in the addition of a nonlocal term to the potential. A quadratic moment approximation is used. As regards the inhibition of reactions inside the nucleus by the Pauli principle, an effective interaction with a relatively simple analytical form and easy to use for systematic analyses was determined [fr
Total and elastic electron scattering cross sections from Xe at intermediate and high energies
International Nuclear Information System (INIS)
Garcia, G; Pablos, J L de; Blanco, F; Williart, A
2002-01-01
Experimental total electron scattering cross sections from Xe in the energy range 300-5000 eV have been obtained with experimental errors of about 3%. The method was based on the measurement of the attenuation of a linear electron beam through a Xe gas cell in combination with an electron spectroscopy technique to analyse the energy of the transmitted electrons. Differential and integral elastic cross sections have been calculated using a scattering potential method which includes relativistic effects. The consistency of our theoretical and experimental results is also discussed in the paper. Finally, analytical formulae depending on two parameters, namely the number of target electrons and the atomic polarizability, are given to reproduce the experimental data for Ne, Ar, Kr and Xe in the energy range 500-10 000 eV
Small-angle p-p elastic scattering at energies between 285 and 572 Me V
Aebischer, D; Greeniaus, L G; Hess, R; Junod, A; Lechanoine-Leluc, C; Nikles, J C; Rapin, D; Serre, Claude; Werren, D W
1976-01-01
Low energy proton-proton elastic scattering has been studied using an arrangement of multiwire proportional chambers at the CERN synchrocyclotron. Accurate measurements of the angular distribution for laboratory scattering angles in the range 1.5 to 10 degrees have been made at eight incident kinetic energies between 285 and 572 MeV. The interferences between the Coulomb and nuclear scattering amplitudes is used to determine the ratio alpha /sub p/=Re phi /sup N //sub +/(o)/Im phi /sup N//sub +/(o), where phi /sup N//sub +/(o) is the non-flip nuclear forward amplitude. alpha p is found to be positive and falling with energy, but is sensitive to the type of parameterization used. Reasonable consistency with dispersion relation calculations is obtained. (21 refs).
Gradient-index phononic crystal lens-based enhancement of elastic wave energy harvesting
Tol, S.; Degertekin, F. L.; Erturk, A.
2016-08-01
We explore the enhancement of structure-borne elastic wave energy harvesting, both numerically and experimentally, by exploiting a Gradient-Index Phononic Crystal Lens (GRIN-PCL) structure. The proposed GRIN-PCL is formed by an array of blind holes with different diameters on an aluminum plate, where the blind hole distribution is tailored to obtain a hyperbolic secant gradient profile of refractive index guided by finite-element simulations of the lowest asymmetric mode Lamb wave band diagrams. Under plane wave excitation from a line source, experimentally measured wave field validates the numerical simulation of wave focusing within the GRIN-PCL domain. A piezoelectric energy harvester disk located at the first focus of the GRIN-PCL yields an order of magnitude larger power output as compared to the baseline case of energy harvesting without the GRIN-PCL on the uniform plate counterpart.
Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial
Directory of Open Access Journals (Sweden)
Riaz U. Ahmed
2014-11-01
Full Text Available This letter presents the possibility of energy scavenging (ES utilizing the physics of acousto-elastic metamaterial (AEMM at low frequencies (<∼3KHz. It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester, simultaneously. AEMM’s are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ∼3 KHz, maximum power in the micro Watts (∼35µW range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (∼30nW power against 10KΩ resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ∼10µW – ∼90µW between 0.2 KHz and 1.5 KHz acoustic frequencies.
Effective elastic properties of damaged isotropic solids
International Nuclear Information System (INIS)
Lee, U Sik
1998-01-01
In continuum damage mechanics, damaged solids have been represented by the effective elastic stiffness into which local damage is smoothly smeared. Similarly, damaged solids may be represented in terms of effective elastic compliances. By virtue of the effective elastic compliance representation, it may become easier to derive the effective engineering constants of damaged solids from the effective elastic compliances, all in closed form. Thus, in this paper, by using a continuum modeling approach based on both the principle of strain energy equivalence and the equivalent elliptical micro-crack representation of local damage, the effective elastic compliance and effective engineering constants are derived in terms of the undamaged (virgin) elastic properties and a scalar damage variable for both damaged two-and three-dimensional isotropic solids
Energy-loss of He ions in carbon allotropes studied by elastic resonance in backscattering spectra
Energy Technology Data Exchange (ETDEWEB)
Tosaki, Mitsuo, E-mail: tosaki.mitsuo.3v@kyoto-u.ac.jp [Radioisotope Research Center, Kyoto University, Kyoto 606-8501 (Japan); Rauhala, Eero [Department of Physics, University of Helsinki (Finland)
2015-10-01
Backscattering spectra for {sup 4}He ions incident on carbon allotropes have been measured in the energy range from 4.30 to 4.95 MeV in steps of 50–100 keV at scattering angles of 106° and 170°. We used three carbon allotropes: graphite, diamond and amorphous carbon. For all these allotropes, we can observe the sharp ({sup 4}He, {sup 12}C) elastic nuclear resonance at the He ion energy of 4.265 MeV in the backscattering spectra. By varying the incident He energy, we have systematically analyzed the profiles of the resonance peaks to study the energy-loss processes: stopping cross-sections and energy-loss straggling around the interesting region of the stopping maximum at about 500 keV. We focus on the resonance profiles and investigate an allotropic effect concerning the energy-loss. Furthermore, an energy bunching effect on the straggling is presented and the mechanism is discussed.
Energy-efficient routing, modulation and spectrum allocation in elastic optical networks
Tan, Yanxia; Gu, Rentao; Ji, Yuefeng
2017-07-01
With tremendous growth in bandwidth demand, energy consumption problem in elastic optical networks (EONs) becomes a hot topic with wide concern. The sliceable bandwidth-variable transponder in EON, which can transmit/receive multiple optical flows, was recently proposed to improve a transponder's flexibility and save energy. In this paper, energy-efficient routing, modulation and spectrum allocation (EE-RMSA) in EONs with sliceable bandwidth-variable transponder is studied. To decrease the energy consumption, we develop a Mixed Integer Linear Programming (MILP) model with corresponding EE-RMSA algorithm for EONs. The MILP model jointly considers the modulation format and optical grooming in the process of routing and spectrum allocation with the objective of minimizing the energy consumption. With the help of genetic operators, the EE-RMSA algorithm iteratively optimizes the feasible routing path, modulation format and spectrum resources solutions by explore the whole search space. In order to save energy, the optical-layer grooming strategy is designed to transmit the lightpath requests. Finally, simulation results verify that the proposed scheme is able to reduce the energy consumption of the network while maintaining the blocking probability (BP) performance compare with the existing First-Fit-KSP algorithm, Iterative Flipping algorithm and EAMGSP algorithm especially in large network topology. Our results also demonstrate that the proposed EE-RMSA algorithm achieves almost the same performance as MILP on an 8-node network.
Addressing preservation of elastic contrast in energy-filtered transmission electron microscopy
Energy Technology Data Exchange (ETDEWEB)
Brown, H.G.; D' Alfonso, A.J.; Forbes, B.D.; Allen, L.J., E-mail: lja@unimelb.edu.au
2016-01-15
Energy-filtered transmission electron microscopy (EFTEM) images with resolutions of the order of an Ångström can be obtained using modern microscopes corrected for chromatic aberration. However, the delocalized nature of the transition potentials for atomic ionization often confounds direct interpretation of EFTEM images, leading to what is known as “preservation of elastic contrast”. In this paper we demonstrate how more interpretable images might be obtained by scanning with a focused coherent probe and incoherently averaging the energy-filtered images over probe position. We dub this new imaging technique energy-filtered imaging scanning transmission electron microscopy (EFISTEM). We develop a theoretical framework for EFISTEM and show that it is in fact equivalent to precession EFTEM, where the plane wave illumination is precessed through a range of tilts spanning the same range of angles as the probe forming aperture in EFISTEM. It is demonstrated that EFISTEM delivers similar results to scanning transmission electron microscopy with an electron energy-loss spectrometer but has the advantage that it is immune to coherent aberrations and spatial incoherence of the probe and is also more resilient to scan distortions. - Highlights: • Interpretation of EFTEM images is complicated by preservation of elastic contrast. • More direct images obtained by scanning with a focused coherent probe and averaging. • This is equivalent to precession EFTEM through the solid angle defined by the probe. • Also yields similar results to energy-loss scanning transmission electron microscopy. • Scanning approach immune to probe aberrations and resilient to scan distortions.
International Nuclear Information System (INIS)
Nakamura, A.; Satta, L.
1985-03-01
The tensor analyzing power for pd backward elastic scattering is calculated in the energy range 150 <= Tsub(p) <= 800 MeV. Two main contributions are considered: the one nucleon exchange and the so called triangle graph, including pp → πd as a subprocess. The pd backward elastic cross section and tensor analyzing power are fairly well reproduced by the model. (author)
The calibration of elastic scattering angular distribution at low energies on HIRFL-RIBLL
Energy Technology Data Exchange (ETDEWEB)
Zhang, G.X. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Zhang, G.L., E-mail: zgl@buaa.edu.cn [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Lin, C.J., E-mail: cjlin@ciae.ac.cn [China Institute of Atomic Energy, Beijing 102413 (China); Qu, W.W. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); School of Radiation Medicine and Protection, Medical College of Soochow University, Soochow 215123 (China); Yang, L.; Ma, N.R. [China Institute of Atomic Energy, Beijing 102413 (China); Zheng, L. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Jia, H.M.; Sun, L.J. [China Institute of Atomic Energy, Beijing 102413 (China); Liu, X.X.; Chu, X.T.; Yang, J.C. [School of Physics and Nuclear Energy Engineering, Beihang University, Beijing 100191 (China); Wang, J.S.; Xu, S.W.; Ma, P.; Ma, J.B.; Jin, S.L.; Bai, Z.; Huang, M.R. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Zang, H.L. [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); and others
2017-02-21
The precise calibration of angular distribution of heavy-ion elastic scattering induced by Radioactive Ion Beams (RIBs) at energies around Coulomb barrier on the Radioactive Ion Beam Line in Lanzhou (RIBLL) at the Heavy-Ion Research Facility in Lanzhou (HIRFL) is presented. The beam profile and the scattering angles on the target are deduced by a measurement with two Multi Wire Proportional Chambers (MWPC), and four sets of detector telescopes (including Double-sided Silicon Strip Detectors (DSSD) placed systematically along the beam line, incorporating with Monte Carlo simulation. The MWPCs were used to determine the beam trajectory before the target, and the energies and the positions of scattered particles on the detectors were measured by the DSSDs. Minor corrections on the beam spot and the detector position are performed by assuming the pure Rutherford scattering at angles which are smaller than the related grazing angle. This method is applied for the elastic scattering of {sup 17}F on {sup 89}Y target at E{sub lab}=59 MeV and 50 MeV.
Study of the proton-proton elastic scattering at high energies through eikonal models
International Nuclear Information System (INIS)
Martini, Alvaro Favinha
1995-01-01
The proton-proton elastic scattering in the center of mass energy region 23 to 63 GeV is investigated through a multiple diffraction model. As an introduction to the subject, a detailed review of the fundamental basis of the Multiple Diffraction Formalism and a survey of the multiple diffraction models (geometrical) currently used are presented. The goal of this investigation is to reformulate one of these models, which makes use of an elementary (parton-parton) amplitude purely imaginary and is not able to predict the ρ-parameter (the ratio of the forward real and imaginary parts of the hadronic amplitude). Introducing a real part for the elementary amplitude proportional to the imaginary part, improvements in the formalism are obtained. It is shown that this new approach is able to reproduce all experimental data on differential and integrated cross sections (total, elastic and inelastic), but not the ρ-parameter as function of the energy. Then, starting from fitting of this parameter an overall reproduction of the physical observables is obtained, with the exception of the dip region (diffractive minimum in the differential cross section) overall description are also not firmly reached in all these models. Finally, alternatives to improve the results in a future research are suggested and discussed. (author)
International Nuclear Information System (INIS)
Abegg, R.; Davis, C.A.; Delheij, P.P.J.; Greeniaus, L.G.; Healey, D.C.; Miller, C.A.; Wait, G.D.; Ahmad, M.; Green, P.W.; Lapointe, C.; McDonald, W.J.; Moss, G.A.; Rodning, N.L.; Roy, G.; Ye, Y.
1989-06-01
In order to improve existing I=0 phase shift solutions, the spin correlation parameter, A NN , and the analyzing powers, A 0N and A N0 , have been measured in n-p elastic scattering over an angular range of 50 degrees -150 degrees (c.m.) at three neutron energies, 220, 325 and 425 MeV to an absolute accuracy of ±0.03. The data have a profound effect on various phase parameters, particularly the 1 P 1 , 3 D 2 and ε 1 phase parameters which in some cases change by almost a degree. With exception of the highest energy, the data support the predictions of the latest version of the Bonn potential. Also the analyzing power data (A 0N and A N0 ) measured at 477 MeV in a different experiment over a limited angular range (60 degrees - 80 degrees (c.m.)) are reported here. (Author) 30 refs., 10 figs., 5 tabs
Saleem, Mohammed; Morlot, Sandrine; Hohendahl, Annika; Manzi, John; Lenz, Martin; Roux, Aurélien
2015-02-01
In endocytosis, scaffolding is one of the mechanisms to create membrane curvature by moulding the membrane into the spherical shape of the clathrin cage. However, the impact of membrane elastic parameters on the assembly and shape of clathrin lattices has never been experimentally evaluated. Here, we show that membrane tension opposes clathrin polymerization. We reconstitute clathrin budding in vitro with giant unilamellar vesicles (GUVs), purified adaptors and clathrin. By changing the osmotic conditions, we find that clathrin coats cause extensive budding of GUVs under low membrane tension while polymerizing into shallow pits under moderate tension. High tension fully inhibits polymerization. Theoretically, we predict the tension values for which transitions between different clathrin coat shapes occur. We measure the changes in membrane tension during clathrin polymerization, and use our theoretical framework to estimate the polymerization energy from these data. Our results show that membrane tension controls clathrin-mediated budding by varying the membrane budding energy.
Directory of Open Access Journals (Sweden)
Yang Yu
2013-01-01
Full Text Available The structural scheme of mechanical elastic energy storage (MEES system served by permanent magnet synchronous motor (PMSM and bidirectional converters is designed. The aim of the research is to model and control the complex electromechanical system. The mechanical device of the complex system is considered as a node in generalized coordinate system, the terse nonlinear dynamic model of electromechanical coupling for the electromechanical system is constructed through Lagrange-Maxwell energy method, and the detailed deduction of the mathematical model is presented in the paper. The theory of direct feedback linearization (DFL is applied to decouple the nonlinear dynamic model and convert the developed model from nonlinear to linear. The optimal control theory is utilized to accomplish speed tracking control for the linearized system. The simulation results in three different cases show that the proposed nonlinear dynamic model of MEES system is correct; the designed algorithm has a better control performance in contrast with the conventional PI control.
Evolving and energy dependent optical model description of heavy-ion elastic scattering
International Nuclear Information System (INIS)
Michaelian, K.
1996-01-01
We present the application of a genetic algorithm to the problem of determining an energy dependent optical model description of heavy-ion elastic scattering. The problem requires a search for the global best optical model potential and its energy dependence in a very rugged 12 dimensional parameter space of complex topographical features with many local minima. Random solutions are created in the first generation. The fitness of a solution is related to the χ 2 fit of the calculated differential cross sections with the experimental data. Best fit solutions are evolved through cross over and mutation following the biological example. This genetic algorithm approach combined with local gradient minimization is shown to provide a global, complete and extremely efficient search method, well adapted to complex fitness landscapes. These characteristics, combined with the facility of application, should make it the search method of choice for a wide variety of problems from nuclear physics. (Author)
Formation Energies of Native Point Defects in Strained-Layer Superlattices (Postprint)
2017-06-05
potential; bulk materials; total energy calculations; entropy; strained- layer superlattice (SLS) 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...AFRL-RX-WP-JA-2017-0217 FORMATION ENERGIES OF NATIVE POINT DEFECTS IN STRAINED- LAYER SUPERLATTICES (POSTPRINT) Zhi-Gang Yu...2016 Interim 11 September 2013 – 5 November 2016 4. TITLE AND SUBTITLE FORMATION ENERGIES OF NATIVE POINT DEFECTS IN STRAINED- LAYER SUPERLATTICES
Wave energy transfer in elastic half-spaces with soft interlayers.
Glushkov, Evgeny; Glushkova, Natalia; Fomenko, Sergey
2015-04-01
The paper deals with guided waves generated by a surface load in a coated elastic half-space. The analysis is based on the explicit integral and asymptotic expressions derived in terms of Green's matrix and given loads for both laminate and functionally graded substrates. To perform the energy analysis, explicit expressions for the time-averaged amount of energy transferred in the time-harmonic wave field by every excited guided or body wave through horizontal planes and lateral cylindrical surfaces have been also derived. The study is focused on the peculiarities of wave energy transmission in substrates with soft interlayers that serve as internal channels for the excited guided waves. The notable features of the source energy partitioning in such media are the domination of a single emerging mode in each consecutive frequency subrange and the appearance of reverse energy fluxes at certain frequencies. These effects as well as modal and spatial distribution of the wave energy coming from the source into the substructure are numerically analyzed and discussed.
First-principles investigation of strain effects on the energy gaps in silicon nanoclusters
International Nuclear Information System (INIS)
Peng, X-H; Alizadeh, A; Bhate, N; Varanasi, K K; Kumar, S K; Nayak, S K
2007-01-01
First-principles density functional calculations were performed to study strain effects on the energy gaps in silicon nanoclusters with diameter ranging from 0.6 to 2 nm. Hydrostatic and non-hydrostatic strains have been found to affect the energy gaps differently. For the same strain energy density, non-hydrostatic strain leads to a significantly larger change in the energy gap of silicon clusters compared to that of the hydrostatic strain case. In contrast, hydrostatic and non-hydrostatic strain effects on the energy gaps of bulk Si or larger size Si quantum dots are comparable. Non-hydrostatic strains break the tetrahedral bonding symmetry in silicon, resulting in significant variation in the energy gaps due to the splitting of the degenerate orbitals in the clusters. Our results suggest that the combination of energy gaps and strains permits the engineering of photoluminescence in silicon nanoclusters and offers the possibility of designing novel optical devices and chemical sensors
International Nuclear Information System (INIS)
Murphy, M.C.; Batte, A.D.; Stringer, M.B.
1979-01-01
High strain fatigue problem in steam turbine. Cyclic stress strain hysteresis loops and stress relaxation behaviour in 16 h dwell period tests. Variation of stress and strain during tests under nominally strain controlled conditions. Definition of test conditions and of criteria for crack initiation and failure. Comparison of reverse bend and push pull failure data. (orig.) 891 RW/orig. 892 RKD [de
International Nuclear Information System (INIS)
Stribeck, Norbert; Zeinolebadi, Ahmad; Fakirov, Stoyko; Bhattacharyya, Debes; Botta, Stephan
2013-01-01
Straining of PVA/PE and PVA/PP blends (70:30) is monitored by small-angle x-ray scattering (SAXS). Sheet-extruded films with different predraw ratio are investigated. The discrete SAXS of predrawn samples originates from polyolefin nanofibrils inside of polyolefin microfibrils immersed in a PVA matrix. PE nanofibrils deform less than the macroscopic strain without volume change. PP nanofibrils experience macroscopic strain. They lengthen but their diameter does not decrease. This is explained by strain-induced crystallization of PP from an amorphous depletion shell around the core of the nanofibril. The undrawn PVA/PE film exhibits isotropic semicrystalline nanostructure. Undrawn PVA/PP holds PP droplets containing oriented stacks of semicrystalline PP like neat precursors of hard-elastic thermoplasts. Respective predrawn films are softer than the undrawn material, indicating conversion into the hard-elastic state. Embedding of the polyolefin significantly retards neck formation. The polyolefin microfibrils can easily be extracted from the water-soluble matrix. (paper)
Mitchell, Michael R.; Leibler, Stanislas
2018-05-01
The abundance of available static protein structural data makes the more effective analysis and interpretation of this data a valuable tool to supplement the experimental study of protein mechanics. Structural displacements can be difficult to analyze and interpret. Previously, we showed that strains provide a more natural and interpretable representation of protein deformations, revealing mechanical coupling between spatially distinct sites of allosteric proteins. Here, we demonstrate that other transformations of displacements yield additional insights. We calculate the divergence and curl of deformations of the transmembrane channel KcsA. Additionally, we introduce quantities analogous to bend, splay, and twist deformation energies of nematic liquid crystals. These transformations enable the decomposition of displacements into different modes of deformation, helping to characterize the type of deformation a protein undergoes. We apply these calculations to study the filter and gating regions of KcsA. We observe a continuous path of rotational deformations physically coupling these two regions, and, we propose, underlying the allosteric interaction between these regions. Bend, splay, and twist distinguish KcsA gate opening, filter opening, and filter-gate coupling, respectively. In general, physically meaningful representations of deformations (like strain, curl, bend, splay, and twist) can make testable predictions and yield insights into protein mechanics, augmenting experimental methods and more fully exploiting available structural data.
Non-resonant energy harvester with elastic constraints for low rotating frequencies
Machado, Sebastián P.; Febbo, Mariano; Gatti, Claudio D.; Ramirez, José M.
2017-11-01
This paper presents a non-resonant piezoelectric energy harvester (PEH) which is designed to capture energy from low frequency rotational vibration. The proposed device works out of the plane of rotation where the motion of a mass-spring system is transferred to a piezoelectric layer with the intention to generate energy to power wireless structural monitoring systems or sensors. The mechanical structure is formed by two beams with rigid and elastic boundary conditions at the clamped end. On the free boundaries, heavy masses connected by a spring are placed in order to increase voltage generation and diminish the natural frequency. A mathematical framework and the equations governing the energy-harvesting system are presented. Numerical simulations and experimental verifications are performed for different rotation speeds ranging from 0.7 to 2.5 Hz. An output power of 125 μW is obtained for maximum rotating frequency demonstrating that the proposed design can collect enough energy for the suggested application.
On the limitations introduced by energy spread in elastic recoil detection analysis
International Nuclear Information System (INIS)
Szilagyi, E.
2001-01-01
Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV 127 I 23+ ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed
On the limitations introduced by energy spread in elastic recoil detection analysis
Energy Technology Data Exchange (ETDEWEB)
Szilagyi, E. E-mail: szilagyi@rmki.kfki.hu
2001-07-01
Improvements in experimental techniques have led to monolayer depth resolution in heavy ion elastic recoil detection analysis (HI-ERDA). Evaluation of the spectra, however, is not trivial. The spectra, using even the best experimental set-up, are subject to finite energy resolution of both extrinsic and intrinsic origin. A proper account for energy spread is necessary to extract the correct depth profile from the measured spectra. With calculation of the correct energy (or depth) resolution of a given method, one can decide in advance whether or not the method will resolve details of interest in the depth profile. To achieve the best depth resolution, it is also possible to find optimum parameters for the experiments. The limitations introduced by the energy spread effects are discussed. An example for simulation is shown for high energy resolution HI-ERDA measurements. Satisfactory agreement between the simulated and the measured HI-ERDA spectra taken by 60 MeV {sup 127}I{sup 23+} ions on highly oriented pyrolythic graphite (HOPG) sample is found, in spite of the non-equilibrium charge state of the recoils and the difference in the stopping powers caused by the given charge state of the incident ion and the recoil, which are not taken into account. To achieve more precise data evaluation these effects should be included in simulation codes, or all the subspectra corresponding to different recoils charge states should be measured and summed.
Aero-hydro-elastic simulation platform for wave energy systems and floating wind turbines
Energy Technology Data Exchange (ETDEWEB)
Kallesoee, B.S.
2011-01-15
This report present results from the PSO project 2008-1-10092 entitled Aero-Hydro-Elastic Simulation Platform for Wave Energy Systems and floating Wind Turbines that deals with measurements, modelling and simulations of the world's first combined wave and wind energy platform. The floating energy conversion platform, Poseidon, is owned and operated by Floating Power Plant A/S. The platform has been operating for two test periods; one period where it was operating as a wave energy conversion platform only and one period where the three turbines was mounted and the platform operated as a combined wind and wave energy platform. The PSO project has equipped the platform with comprehensive measurements equipment for measuring platform motion, wave and wind conditions and turbine loads. Data from the first test period has been used for determine if the turbine could be mounted on the platform. Preliminary analysis of data from the second test period indicates that the platform is suitable as wind turbine foundation and that the turbines reduce the platform motion. (Author)
Ajaxon, Ingrid; Acciaioli, Alice; Lionello, Giacomo; Ginebra, Maria-Pau; Öhman-Mägi, Caroline; Baleani, Massimiliano; Persson, Cecilia
2017-10-01
Calcium phosphate cements (CPCs) should ideally have mechanical properties similar to those of the bone tissue the material is used to replace or repair. Usually, the compressive strength of the CPCs is reported and, more rarely, the elastic modulus. Conversely, scarce or no data are available on Poisson's ratio and strain-to-crack-initiation. This is unfortunate, as data on the elastic response is key to, e.g., numerical model accuracy. In this study, the compressive behaviour of brushite, monetite and apatite cements was fully characterised. Measurement of the surface strains was done using a digital image correlation (DIC) technique, and compared to results obtained with the commonly used built-in displacement measurement of the materials testers. The collected data showed that the use of fixed compression platens, as opposed to spherically seated ones, may in some cases underestimate the compressive strength by up to 40%. Also, the built-in measurements may underestimate the elastic modulus by up to 62% as compared to DIC measurements. Using DIC, the brushite cement was found to be much stiffer (24.3 ± 2.3GPa) than the apatite (13.5 ± 1.6GPa) and monetite (7.1 ± 1.0GPa) cements, and elastic moduli were inversely related to the porosity of the materials. Poisson's ratio was determined to be 0.26 ± 0.02 for brushite, 0.21 ± 0.02 for apatite and 0.20 ± 0.03 for monetite. All investigated CPCs showed low strain-to-crack-initiation (0.17-0.19%). In summary, the elastic modulus of CPCs is substantially higher than previously reported and it is concluded that an accurate procedure is a prerequisite in order to properly compare the mechanical properties of different CPC formulations. It is recommended to use spherically seated platens and measuring the strain at a relevant resolution and on the specimen surface. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.
Zhu, Haiyan; Shi, Liwei; Li, Shuaiqi; Duan, Yifeng; Zhang, Shaobo; Xia, Wangsuo
2018-04-01
The effects of hydrostatic pressure and biaxial strains on the elastic and electronic properties of a superhard material t-C8B2N2 have been studied using first-principles calculations. The structure is proven to be mechanically and dynamically stable under the applied external forces. All the elastic constants (except C66) and elastic modulus increase (decrease) with increasing pressure and compressive (tensile) biaxial strain ɛxx. A microscopic model is used to calculate the Vicker's hardness of every single bond as well as the crystal. The hardness of t-C8B2N2 (64.7 GPa) exceeds that of c-BN (62 GPa) and increases obviously by employing pressure and compressive ɛxx. Furthermore, the Debye temperature and anisotropy of sound velocities for t-C8B2N2 have been discussed. t-C8B2N2 undergoes an indirect to direct bandgap transition when ɛxx > 2%; however, the indirect bandgap character of the material remains under pressure.
Analysis of pp and pp-bar elastic scattering amplitudes at high energies
Energy Technology Data Exchange (ETDEWEB)
Ferreira, E.; Kodama, T.; Kohara, A.K. [Universidade Federal do Rio de Janeiro (IF/UFRJ), RJ (Brazil). Inst. de Fisica
2012-07-01
Full text: A careful analysis of high energies elastic scattering data at 7 TeV for pp, 1800 - 1950 GeV for pp-bar and 540 -541 GeV for pp-bar in terms of its amplitudes has been performed as natural extension of previous analysis for lower energies. The disentanglement of the real and imaginary parts is written consistently with constraints from dispersion relations for amplitudes and for slopes, and also satisfying the universal asymptotic behavior for large |t| values due to the three gluon Exchange process. Values for the imaginary and real slopes and for the total cross section at 7 TeV, 1800-1950 GeV and 540-541 GeV are presented, and the shape of the differential cross section at 14 TeV, with a dip/bump structure more marked and at a smaller values of |t| is predicted. It is predicted that future measurements at large |t| will be connected smoothly with the perturbative tail observed in the interval 5.5 to 14.2 GeV{sup 2} at lower energies and that a marked dip would be observed in pp-bar scattering near this tail range. It is stressed for the consistent description of elastic pp and pp-bar data and pointed out the importance of the future measurements in the Coulomb interference range and in the transition range to the perturbative tail where the perturbative and non-perturbative effects appears together. (author)
Strain energy storage and dissipation rate in active cell mechanics
Agosti, A.; Ambrosi, D.; Turzi, S.
2018-05-01
When living cells are observed at rest on a flat substrate, they can typically exhibit a rounded (symmetric) or an elongated (polarized) shape. Although the cells are apparently at rest, the active stress generated by the molecular motors continuously stretches and drifts the actin network, the cytoskeleton of the cell. In this paper we theoretically compare the energy stored and dissipated in this active system in two geometric configurations of interest: symmetric and polarized. We find that the stored energy is larger for a radially symmetric cell at low activation regime, while the polar configuration has larger strain energy when the active stress is beyond a critical threshold. Conversely, the dissipation of energy in a symmetric cell is always larger than that of a nonsymmetric one. By a combination of symmetry arguments and competition between surface and bulk stress, we argue that radial symmetry is an energetically expensive metastable state that provides access to an infinite number of lower-energy states, the polarized configurations.
International Nuclear Information System (INIS)
Tuerkekul, Berna; Unakitan, Goekhan
2011-01-01
Agriculture has an important role in every country's development. Particularly, the contribution of agriculture to development and competitiveness is increasing with agricultural productivity growth. Productivity, in turn, is closely associated with direct and indirect use of energy as an input. Therefore, the importance of energy in agriculture cannot be denied as one of the basic inputs to the economic growth process. Following the importance of energy in Turkish agriculture, this study aims to estimate the long- and short-run relationship of energy consumption, agricultural GDP, and energy prices via co-integration and error correction (ECM) analysis. Annual data from 1970 to 2008 for diesel and electricity consumptions are utilized to estimate long-run and short-run elasticities. According to ECM analysis, for the diesel demand model, the long-run income and price elasticities were calculated as 1.47 and -0.38, respectively. For the electricity demand model, income and price elasticities were calculated at 0.19 and -0.72, respectively, in the long run. Briefly, in Turkey, support for energy use in agriculture should be continued in order to ensure sustainability in agriculture, increase competitiveness in international markets, and balance farmers' income. - Research highlights: → We estimate the long and short run elasticities for diesel and electricity demands in agriculture. → The long-run income and price elasticities calculated as 1.47 and 0.38, respectively for diesel. → The long run Income and price elasticities calculated as 0.19 and 0.72 for electricity.
Energy Technology Data Exchange (ETDEWEB)
Tuerkekul, Berna, E-mail: berna.turkekul@ege.edu.t [Department of Agricultural Economics, Faculty of Agriculture, Ege University, 35100 Izmir (Turkey); Unakitan, Goekhan, E-mail: unakitan@nku.edu.t [Department of Agricultural Economics, Faculty of Agriculture, Namik Kemal University, Tekirdag (Turkey)
2011-05-15
Agriculture has an important role in every country's development. Particularly, the contribution of agriculture to development and competitiveness is increasing with agricultural productivity growth. Productivity, in turn, is closely associated with direct and indirect use of energy as an input. Therefore, the importance of energy in agriculture cannot be denied as one of the basic inputs to the economic growth process. Following the importance of energy in Turkish agriculture, this study aims to estimate the long- and short-run relationship of energy consumption, agricultural GDP, and energy prices via co-integration and error correction (ECM) analysis. Annual data from 1970 to 2008 for diesel and electricity consumptions are utilized to estimate long-run and short-run elasticities. According to ECM analysis, for the diesel demand model, the long-run income and price elasticities were calculated as 1.47 and -0.38, respectively. For the electricity demand model, income and price elasticities were calculated at 0.19 and -0.72, respectively, in the long run. Briefly, in Turkey, support for energy use in agriculture should be continued in order to ensure sustainability in agriculture, increase competitiveness in international markets, and balance farmers' income. - Research highlights: {yields} We estimate the long and short run elasticities for diesel and electricity demands in agriculture. {yields} The long-run income and price elasticities calculated as 1.47 and 0.38, respectively for diesel. {yields} The long run Income and price elasticities calculated as 0.19 and 0.72 for electricity.
The Strain Energy, Seismic Moment and Magnitudes of Large Earthquakes
Purcaru, G.
2004-12-01
The strain energy Est, as potential energy, released by an earthquake and the seismic moment Mo are two fundamental physical earthquake parameters. The earthquake rupture process ``represents'' the release of the accumulated Est. The moment Mo, first obtained in 1966 by Aki, revolutioned the quantification of earthquake size and led to the elimination of the limitations of the conventional magnitudes (originally ML, Richter, 1930) mb, Ms, m, MGR. Both Mo and Est, not in a 1-to-1 correspondence, are uniform measures of the size, although Est is presently less accurate than Mo. Est is partitioned in seismic- (Es), fracture- (Eg) and frictional-energy Ef, and Ef is lost as frictional heat energy. The available Est = Es + Eg (Aki and Richards (1980), Kostrov and Das, (1988) for fundamentals on Mo and Est). Related to Mo, Est and Es, several modern magnitudes were defined under various assumptions: the moment magnitude Mw (Kanamori, 1977), strain energy magnitude ME (Purcaru and Berckhemer, 1978), tsunami magnitude Mt (Abe, 1979), mantle magnitude Mm (Okal and Talandier, 1987), seismic energy magnitude Me (Choy and Boatright, 1995, Yanovskaya et al, 1996), body-wave magnitude Mpw (Tsuboi et al, 1998). The available Est = (1/2μ )Δ σ Mo, Δ σ ~=~average stress drop, and ME is % \\[M_E = 2/3(\\log M_o + \\log(\\Delta\\sigma/\\mu)-12.1) ,\\] % and log Est = 11.8 + 1.5 ME. The estimation of Est was modified to include Mo, Δ and μ of predominant high slip zones (asperities) to account for multiple events (Purcaru, 1997): % \\[E_{st} = \\frac{1}{2} \\sum_i {\\frac{1}{\\mu_i} M_{o,i} \\Delta\\sigma_i} , \\sum_i M_{o,i} = M_o \\] % We derived the energy balance of Est, Es and Eg as: % \\[ E_{st}/M_o = (1+e(g,s)) E_s/M_o , e(g,s) = E_g/E_s \\] % We analyzed a set of about 90 large earthquakes and found that, depending on the goal these magnitudes quantify differently the rupture process, thus providing complementary means of earthquake characterization. Results for some
Beskopylny, Alexey; Kadomtseva, Elena; Strelnikov, Grigory
2017-10-01
The stress-strain state of a rectangular slab resting on an elastic foundation is considered. The slab material is isotropic. The slab has stiffening ribs that directed parallel to both sides of the plate. Solving equations are obtained for determining the deflection for various mechanical and geometric characteristics of the stiffening ribs which are parallel to different sides of the plate, having different rigidity for bending and torsion. The calculation scheme assumes an orthotropic slab having different cylindrical stiffness in two mutually perpendicular directions parallel to the reinforcing ribs. An elastic foundation is adopted by Winkler model. To determine the deflection the Bubnov-Galerkin method is used. The deflection is taken in the form of an expansion in a series with unknown coefficients by special polynomials, which are a combination of Legendre polynomials.
Nucleon charge exchange reaction and antiproton elastic scattering at intermediate energies
International Nuclear Information System (INIS)
Kronenfeld, J.
1985-02-01
This work treats the medium energy nuclear (p,n) charge exchange reaction to analog states and the low energy elastic scattering of antiprotons and investigates the central aspects of a microscopic theory based on multiple-scattering series which are pertinent to these reactions. A two-step term of the Distorted Wave Impulse Approximation (DWIA) in treating the (p,n) reaction, was included. For the very absorptive p-bar interaction with nuclei we conjecture that a partial infinite summation, constituing a renormalization of the single scattering term of the optical potential series provides the dominant feature of this interaction. In this work the excitation of analog states is calculated and it was found that the (p,n) reaction is described fairly well by the DWIA. In the first part of the work the (p,n) reaction in the energy range 100-200 MeV was treated. The DWIA calculations were based on eikonalization. In the second part of the work the p-barA interaction with the selfconsistent scheme mentioned above, for scattering energies 30-120 MeV, was examined. (author)
An optimization method of VON mapping for energy efficiency and routing in elastic optical networks
Liu, Huanlin; Xiong, Cuilian; Chen, Yong; Li, Changping; Chen, Derun
2018-03-01
To improve resources utilization efficiency, network virtualization in elastic optical networks has been developed by sharing the same physical network for difference users and applications. In the process of virtual nodes mapping, longer paths between physical nodes will consume more spectrum resources and energy. To address the problem, we propose a virtual optical network mapping algorithm called genetic multi-objective optimize virtual optical network mapping algorithm (GM-OVONM-AL), which jointly optimizes the energy consumption and spectrum resources consumption in the process of virtual optical network mapping. Firstly, a vector function is proposed to balance the energy consumption and spectrum resources by optimizing population classification and crowding distance sorting. Then, an adaptive crossover operator based on hierarchical comparison is proposed to improve search ability and convergence speed. In addition, the principle of the survival of the fittest is introduced to select better individual according to the relationship of domination rank. Compared with the spectrum consecutiveness-opaque virtual optical network mapping-algorithm and baseline-opaque virtual optical network mapping algorithm, simulation results show the proposed GM-OVONM-AL can achieve the lowest bandwidth blocking probability and save the energy consumption.
On the rank 1 convexity of stored energy functions of physically linear stress-strain relations
Czech Academy of Sciences Publication Activity Database
Šilhavý, Miroslav; Bertram, A.; Böhlke, T.
2007-01-01
Roč. 86, č. 3 (2007), s. 235-243 ISSN 0374-3535 Institutional research plan: CEZ:AV0Z10190503 Keywords : generalized linear elastic law s * generalized strain measures * rank 1 convexity Subject RIV: BA - General Mathematics Impact factor: 0.743, year: 2007
The exponentiated Hencky-logarithmic strain energy. Improvement of planar polyconvexity
Czech Academy of Sciences Publication Activity Database
Ghiba, I.-D.; Neff, P.; Šilhavý, Miroslav
2015-01-01
Roč. 71, May (2015), s. 48-51 ISSN 0020-7462 Institutional support: RVO:67985840 Keywords : finite isotropis elasticity * polyconvexity * logarithmic strain Subject RIV: BA - General Mathematics Impact factor: 1.920, year: 2015 http://www.sciencedirect.com/science/article/pii/S0020746215000190
Analyzing power for π-p elastic scattering in the energy region of the Roper resonance
International Nuclear Information System (INIS)
Mokhtari, A.; Briscoe, W.J.; Eichon, A.D.; Fitzgerald, D.H.; Kim, G.J.; Nefkens, B.M.K.; Wightman, J.A.; Sadler, M.E.
1986-01-01
High-precision measurements of the analyzing power A/sub N/ in π - p elastic scattering at p/sub π/ = 471--687 MeV/c are presented and compared with the results of recent πN partial-wave analyses (PWA's) by the Karlsruhe-Helsinki, CMU-LBL, and VPI groups. While agreeing with the main features of the measured angular dependence of A/sub N/, the three PWA's yield larger values than the measurements at forward angles at p/sub π/ = 471, 547, and 625 MeV/c. At 687 MeV/c the PWA's do not agree with the data at far backward angles. We estimate the effect of our data on the phase shifts in this energy region, which includes the Roper resonance
Correlations among observables in the neutron-deuteron elastic scattering at low energies
International Nuclear Information System (INIS)
Frederico, T.; Goldman, I.D.
1984-01-01
The 2 S amplitude of the n-d elastic scattering appears like function of the dublet ( 2 a) scattering length in the three nucleons calculations. The correlation of Kcotg 2 δ o with 2 a, with separable N-N potential calculations, is obtained and the result is independent of the N-N potential. The 2 δ o (n-d) values obtained with these lines, using 2 a=.65F (experimental value), agree with p-d data. 2 S and 4 S scattering amplitude and tritium energy (E T ) calculations are performed with the zero-range model and an alternative deduction is proposed. These results for the E T and Kcotg 2 δ o correlation with 2 a show the limitations of this model. (L.C.) [pt
Energy Technology Data Exchange (ETDEWEB)
Khiabani, Nasser; Hasani, Karim [Department of Economics, Institute for Management and Planning Studies, Mokhtar Asgari Str.10, 19395, Tehran (Iran, Islamic Republic of)
2010-09-15
Ignoring technical and allocative inefficiencies or embedding one of them alone in a system of input demands may result in biased elasticities. We consider a comprehensive model including technical inefficiency (in input and output forms) and allocative inefficiency and apply it to panel data from Iran's manufacturing sector. The results show that the presence of both inefficiencies affects the computed elasticities of demand and substitution. Moreover, in spite of current waste of energy in Iran's manufacturing, the elimination of environmental constraints will prompt the manufacturing firms to increase the utilization of energy relative to both capital and labor. (author)
Energy efficient three-layer panels and elastic compliance of their middle layer
Directory of Open Access Journals (Sweden)
Petrov Stanislav
2017-01-01
Full Text Available Three-layer panels are referred to light weight energy efficient building envelopes. According to current trends, mineral wool from basalt fiber is preferable to be used as panels middle layer. All three-layers of the construction together account for mechanical properties, though these layers taken separately have very different mechanical properties. The work of such a composite design has a number of features that require careful consideration when calculating the panels for strength. Thus, it has not yet been described how squeeze reduction of a relatively soft middle layer affects the load bearing capacity of a panel. When panels are exposed to external loads, their middle layer is squeezed thus changing the characteristics of the panel. This effect is particularly evident in supporting structures. Besides, squeeze reduction of the middle layer changes its elastic-plastic propeties. The purpose of this work is to study the effect of the middle layer of an energy efficient panel squeeze reduction on its load bearing capacity. When solving this task, the authors worked out a methodology which takes into account squeeze reduction of a middle layer and its effect on load bearing capacity of the panel. The researches introduced an algorithm for solving this task and created a tool that allows to easily receive the exact solution. The paper presents this methodology and describes a computer program for calculating three-layer panels with account of changing elastic compliance of a middle layer. The main result of the work is an extended methodology of calculation of the panels and an obtained engineering tool that allows to quickly obtain an extended solution.
Sukhanov, Ivan I.; Ditenberg, Ivan A.
2017-12-01
The paper provides a theoretical analysis of elastic stresses and elastic energy distribution in nanostructured metal materials in the vicinity of nanograin boundaries with a high partial disclination density. The analysis demonstrates the stress field distribution in disclination grain boundary configurations as a function of nanograin size, taking into account the superposition of these stresses in screening the disclination pile-ups. It is found that the principal stress tensor components reach maximum values only in disclination planes P ≈ E/25 and that the stress gradients peak at nodal points ∂P/∂x ≈ 0.08E nm-1. The shear stress components are localized within the physical grain size, and the specific elastic energy distribution for such configurations reveals characteristic local maxima which can be the cause for physical broadening of nanograin boundaries.
S-wave elastic scattering of ${\\it o} $-Ps from $\\text {H} _2 $ at low energy
Zhang, J. -Y.
2018-03-08
The confined variational method is applied to investigate the low-energy elastic scattering of ortho-positronium from $\\\\text{H}_2$ by first-principles quantum mechanics. Describing the correlation effect with explicitly correlated Gaussians, we obtain accurate $S$-wave phase shifts and pick-off annihilation parameters for different incident momenta. By a least-squares fit of the data to the effective-range theory, we determine the $S$-wave scattering length, $A_s=2.06a_0$, and the zero-energy value of the pick-off annihilation parameter, $^1\\\\!\\\\text{Z}_\\\\text{eff}=0.1858$. The obtained $^1\\\\!\\\\text{Z}_\\\\text{eff}$ agrees well with the precise experimental value of $0.186(1)$ (J.\\\\ Phys.\\\\ B \\\\textbf{16}, 4065 (1983)) and the obtained $A_s$ agrees well with the value of $2.1(2)a_0$ estimated from the average experimental momentum-transfer cross section for Ps energy below 0.3 eV (J.\\\\ Phys.\\\\ B \\\\textbf{36}, 4191 (2003)).
Abboud, A; Kirchlechner, C; Keckes, J; Conka Nurdan, T; Send, S; Micha, J S; Ulrich, O; Hartmann, R; Strüder, L; Pietsch, U
2017-06-01
The full strain and stress tensor determination in a triaxially stressed single crystal using X-ray diffraction requires a series of lattice spacing measurements at different crystal orientations. This can be achieved using a tunable X-ray source. This article reports on a novel experimental procedure for single-shot full strain tensor determination using polychromatic synchrotron radiation with an energy range from 5 to 23 keV. Microbeam X-ray Laue diffraction patterns were collected from a copper micro-bending beam along the central axis (centroid of the cross section). Taking advantage of a two-dimensional energy-dispersive X-ray detector (pnCCD), the position and energy of the collected Laue spots were measured for multiple positions on the sample, allowing the measurement of variations in the local microstructure. At the same time, both the deviatoric and hydrostatic components of the elastic strain and stress tensors were calculated.
International Nuclear Information System (INIS)
Rao, S.I.; Dimiduk, D.M.; Parthasarathy, T.A.; El-Awady, J.; Woodward, C.; Uchic, M.D.
2011-01-01
The nudged elastic band (NEB) method is used to evaluate activation energies for dislocation intersection cross-slip in face-centered cubic (fcc) nickel and copper, to extend our prior work which used an approximate method. In this work we also extend the study by including Hirth locks (HL) in addition to Lomer-Cottrell locks and glide locks (GL). Using atomistic (molecular statics) simulations with embedded atom potentials we evaluated the activation barrier for a dislocation to transform from fully residing on the glide plane to fully residing on the cross-slip plane when intersecting a 120 o forest dislocation in both Ni and Cu. The initial separation between the screw and the intersecting dislocation on the (1 1 1) glide plane is varied to find a minimum in the activation energy. The NEB method gives energies that are ∼10% lower than those reported in our prior work. It is estimated that the activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming GL in Ni and Cu are ∼0.47 and ∼0.65 eV, respectively, and from the fully cross-slip plane state to the partially cross-slipped state forming LC are ∼0.68 and ∼0.67 eV. The activation energies for cross-slip from the fully glide plane state to the partially cross-slipped state at the 120 o intersection forming HL in Ni and Cu are estimated to be ∼0.09 and ∼0.31 eV, respectively. These values are a factor of 3-20 lower than the activation energy for bulk cross-slip in Ni and, a factor of 2-6 lower than the activation energy for cross-slip in Cu estimated by Friedel-Escaig analysis. These results suggest that cross-slip should nucleate preferentially at selected screw dislocation intersections in fcc materials and the activation energies for such mechanisms are also a function of stacking fault energy.
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Fazal-E-Aleem; Azhar, I.A.
1988-06-01
The various characteristics of pp and antipp elastic scattering at high energies are explained by using the generalized Chou-Yang model which takes into consideration the anisotropic scattering of objects constituting colliding particles. The model is also used to extract the form factor and radius of the ..lambda.. particle.
International Nuclear Information System (INIS)
Grande, P.L.; Fichtner, P.F.P.; Behar, M.; Zawislak, E.F.C.
1988-01-01
Measurements of deepness of implanted ions in carbon films, show the possibility that the energy elastic component given to the medium, could be affected by the ineslastic stopping parcel, which could cause a total stopping power, smaller than the expected. (A.C.A.S.) [pt
Elastic scattering of {sup 12} C by {sup 12} C at intermediate energies
Energy Technology Data Exchange (ETDEWEB)
Khallaf, S A.E. [Department of Physics, Faculty of Science, Assiut University, Assiut, (Egypt); Abdel-Rahman, M A; Abdel-Raheem, S K; Mahmoud, S W.Z. [Department of Physics, Faculty of Science, El-Minia University, El-Minia, (Egypt)
1997-12-31
Using the double folding model (DF), the real part of the central potential for {sup 12} C + {sup 12} C system is derived. This potential as well as the single folding cluster model potential (SFC) were used to calculate the total and differential cross sections for {sup 12} C elastically scattered on {sup 12} C at three laboratory energies; E{sub 1ab}. = 300, 344.5 and 360 MeV. The calculations were carried out using five sets of nucleon nucleon (NN) interaction of the integrable Gaussian form and two sets of parameters for the nuclear matter density of the harmonic oscillator form. The transparency of the target nucleus was found to increase as the projectile energy increases. Good fits between the present calculations and the experimental data as well as the previously published calculations were obtained. The present simple methods used to calculate the real part of the optical potential stand on equal footing with the density dependent (DDM 3 Y) procedure and it reduces the potential computing time enormously. The suitable choice of NN interaction as well as nuclear matter densities is important. 24 figs., 3 tabs.
Korolev, G. A.; Dobrovolsky, A. V.; Inglessi, A. G.; Alkhazov, G. D.; Egelhof, P.; Estradé, A.; Dillmann, I.; Farinon, F.; Geissel, H.; Ilieva, S.; Ke, Y.; Khanzadeev, A. V.; Kiselev, O. A.; Kurcewicz, J.; Le, X. C.; Litvinov, Yu. A.; Petrov, G. E.; Prochazka, A.; Scheidenberger, C.; Sergeev, L. O.; Simon, H.; Takechi, M.; Tang, S.; Volkov, V.; Vorobyov, A. A.; Weick, H.; Yatsoura, V. I.
2018-05-01
The absolute differential cross section for small-angle proton elastic scattering on the proton-rich 8B nucleus has been measured in inverse kinematics for the first time. The experiment was performed using a secondary radioactive beam with an energy of 0.7 GeV/u at GSI, Darmstadt. The active target, namely hydrogen-filled time projection ionization chamber IKAR, was used to measure the energy, angle and vertex point of the recoil protons. The scattering angle of the projectiles was simultaneously determined by the tracking detectors. The measured differential cross section is analyzed on the basis of the Glauber multiple scattering theory using phenomenological nuclear-density distributions with two free parameters. The radial density distribution deduced for 8B exhibits a halo structure with the root-mean-square (rms) matter radius Rm = 2.58 (6) fm and the rms halo radius Rh = 4.24 (25) fm. The results on 8B are compared to those on the mirror nucleus 8Li investigated earlier by the same method. A comparison is also made with previous experimental results and theoretical predictions for both nuclei.
Pion elastic scattering from polarized 13C in the energy region of the P33 resonance
International Nuclear Information System (INIS)
Yifen, Yen
1992-08-01
Asymmetries (A y ) and differential cross sections (dσ/dΩ) were measured for π + and π - elastic scattering using polarized and unpolarized 13 C targets. The experiment was done at the Los Alamos Meson Physics Facility with the pion beam from the Low Energy Pion channel. The scattered pions were detected with the Large Acceptance Spectrometer. The 13 C nuclei in 13 C-enriched 1-butanol were polarized by the dynamic nuclear polarilization method. Angular distributions of both A y and dσ/dΩ were measured below the P 33 resonance at the incident energy of 130 MeV for π + and π - , and above the resonance at 223 MeV for π + and at 226 MeV for π - . In addition, A y and dσ/dΩ were measured in a range of momentum transfers, 1.75 ≤ q ≤ 2.05 fm - , at several energies. At 130 MeV, the values of A y are significantly different from zero for π - scattering. For π + at 130 MeV and for both π - and π + at all other energies, the A y are mostly consistent with zero. Theoretical analyses were done using different nuclear structure models. The data were not reproduced by the presently available nuclear wave functions. It was found that the asymmetry is strongly sensitive to the quadrupole spin flip part of the transition. The data of this thesis complement measurements of the magnetic form factor from electron scattering. In attempts to fit both the asymmetry and the magnetic form factor, it was found that the pion asymmetry data are not reproduced by the wavefunctions which fit the magnetic form factor at low momentum transfers
Alfat, Sayahdin; Kimura, Masato; Firihu, Muhammad Zamrun; Rahmat
2018-05-01
In engineering area, investigation of shape effect in elastic materials was very important. It can lead changing elasticity and surface energy, and also increase of crack propagation in the material. A two-dimensional mathematical model was developed to investigation of elasticity and surface energy in elastic material by Adaptive Finite Element Method. Besides that, behavior of crack propagation has observed for every those materials. The government equations were based on a phase field approach in crack propagation model that developed by Takaishi-Kimura. This research has varied four shape domains where physical properties of materials were same (Young's modulus E = 70 GPa and Poisson's ratio ν = 0.334). Investigation assumptions were; (1) homogeneous and isotropic material, (2) there was not initial cracking at t = 0, (3) initial displacement was zero [u1, u2] = 0) at initial condition (t = 0), and (4) length of time simulation t = 5 with interval Δt = 0.005. Mode I/II or mixed mode crack propagation has been used for the numerical investigation. Results of this studies were very good and accurate to show changing energy and behavior of crack propagation. In the future time, this research can be developed to complex phenomena and domain. Furthermore, shape optimization can be investigation by the model.
International Nuclear Information System (INIS)
Gatti, R; UhlIk, F; Montalenti, F
2008-01-01
We present a novel computational method for finding the concentration profile which minimizes the elastic energy stored in heteroepitaxial islands. Based on a suitable combination of continuum elasticity theory and configurational Monte Carlo, we show that such profiles can be readily found by a simple, yet fully self-consistent, iterative procedure. We apply the method to SiGe/Si islands, considering realistic three-dimensional shapes (pyramids, domes and barns), finding strongly non-uniform distributions of Si and Ge atoms, in qualitative agreement with several experiments. Moreover, our simulated selective-etching profiles display, in some cases, a remarkable resemblance to the experimental ones, opening intriguing questions on the interplay between kinetic, entropic and elastic effects
Elastic scattering of 7Li projectiles in the energy range of 20 to 34 MeV
International Nuclear Information System (INIS)
Khallaf, S.A.E.
1983-01-01
As far as it is known, the Watanabe folding model has not been used to analyse the elastic scattering of 7 Li projectiles. The main purpose of the present work is to calculate the differential cross sections for 7 Li elastic scattering von 90 Zr, 48 , 40 Ca, 16 O and 12 C at incident energies of 20 to 34 MeV using the Watanabe folding model and to study the applicability of this model for 7 Li elastic scattering. The potentials of 7 Li ions are revealed by Taylor expansions of alpha and triton cluster potentials. The resulting differential cross sections are compared with the predicted cross sections using phenomenological potentials of 7 Li ions. (orig./WL)
International Nuclear Information System (INIS)
Isaac Samuel, B.; Choudhary, B.K.; Bhanu Sankara Rao, K.
2010-01-01
Tensile tests were conducted on type 316 L(N) stainless steel over a wide temperature range of 300-1123 K employing strain rates ranging from 3.16 X 10 -5 to 3.16 X 10 -3/s . The variation of strain energy in terms of modulus of resilience and modulus of toughness over the wide range of temperatures and strain rates were examined. The variation in modulus of resilience with temperature and strain rate did not show the signatures of dynamic strain ageing (DSA). However, the modulus of toughness exhibited a plateau at the intermediate temperatures of 523-1023 K. Further, the distribution of energy absorbed till necking and energy absorbed from necking till fracture were found to characterise the deformation and damage processes, respectively, and exhibited anomalous variations in the temperature range 523-823 K and 823-1023 K, respectively. In addition to the observed manifestations of DSA such as serrated load-elongation curve, peaks/plateaus in flow stress, ultimate tensile strength and work hardening rate, negative strain rate sensitivity and ductility minima, the observed anomalous variations in modulus of toughness at intermediate temperatures (523-1023 K) can be regarded as yet another key manifestation of DSA. At temperatures above 1023 K, a sharp decrease in the modulus of toughness and also in the strain energies up to necking and from necking to fracture observed, with increasing temperature and decreasing strain rate, reveal the onset of dynamic recovery leading to early cross slip and climb processes. (author)
Direct strain energy harvesting in automobile tires using piezoelectric PZT-polymer composites
Ende, D.A. van den; Wiel, H.J. van de; Groen, W.A.; Zwaag, S. van der
2012-01-01
Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical
Direct strain energy harvesting in automobile tires using piezoelectric PZT–polymer composites
Van den Ende, D.A.; Van de Wiel, H.J.; Groen, W.A.; Van der Zwaag, S.
2011-01-01
Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical
The influence of elastic strain on the early stages of decomposition in Cu–1.7at% Fe
Rademacher, Thomas; Al-Kassab, Talaat; Kirchheim, Reiner
2009-01-01
with FIM images, alignments of precipitates mainly in < 100 > directions were found. Besides, a general experimental concept to evaluate strain-related effects on the position of the proximate precipitate will be introduced. These analyses of the APT and c
High-energy elastic recoil detection heavy ions for light element analysis
International Nuclear Information System (INIS)
Goppelt-Langer, P.; Yamamoto, S.; Takeshita, H.; Aoki, Y.; Naramoto, H.
1994-01-01
The detection of light and medium heavy elements in not homogeneous solids is a severe problem in ion beam analysis. Heavy elements can be detected by the well established Rutherford backscattering technique (RBS). In a homogeneous host material most impurities can be easily analyzed by secondary ion mass spectroscopy (SIMS). Some isotopes ( 3 He, 6 Li, 10 B) can be measured by nuclear reaction analysis (NRA) using thermal neutrons inducing (n, p) or (n, α) reactions. Others can be detected by energetic ion beams by nuclear reactions (e.g. 15 N( 1 H, αγ) 12 C for analysis of hydrogen). A high content of H, D or T can be also determined by elastic recoil detection using an energetic He beam. The latter technique has been developed to a universal method for detection of light and heavy elements in any target, using a high energetic heavy ion beam and a detector system, which is able to identify the recoils and delivers energy and position of the particles. (author)
International Nuclear Information System (INIS)
Boonekamp, Piet G.M.
2007-01-01
In the Netherlands it seems likely that the large number of new policy measures in the past decade has influenced the response of households to changing prices. To investigate this issue the energy trends in the period 1990-2000 have been simulated with a bottom-up model, applied earlier for scenario studies, and extensive data from surveys. For a number of alternative price cases the elasticity values found are explained using the bottom-up changes in energy trends. One finding is that the specific set of saving options defines for a great part the price response. The price effect has been analysed too in combination with the policy measures standards, subsidies and energy taxes. The simulation results indicate that the elasticity value could be 30-40% higher without these measures. (author)
Rakitin, M. S.; Mirzoev, A. A.; Mirzaev, D. A.
2018-04-01
Mobile hydrogen, when dissolving in metals, redistributes due to the density gradients and elastic stresses, and enables destruction processes or phase transformations in local volumes of a solvent metal. It is rather important in solid state physics to investigate these interactions. The first-principle calculations performed in terms of the density functional theory, are used for thermodynamic simulation of the elastic stress effect on the energy of hydrogen dissolution in α-Fe crystal lattice. The paper presents investigations of the total energy of Fe-H system depending on the lattice parameter. As a result, the relation is obtained between the hydrogen dissolution energy and stress. A good agreement is shown between the existing data and simulation results. The extended equation is suggested for the chemical potential of hydrogen atom in iron within the local stress field. Two parameters affecting the hydrogen distribution are compared, namely local stress and phase transformations.
International Nuclear Information System (INIS)
Ma, Ben
2015-01-01
Although there has been extensive debate in the literature that addresses the impact of urbanization on total energy use, the relative magnitude of each impact channel has not been empirically examined and urbanization's effects on energy transition dynamics in China remains unknown. Using panel datasets at the provincial level from 1986 to 2011, this paper employs dynamic models to investigate both the long-run and short-run elasticities of urbanization on energy intensities and the most significant impact channel is identified. Coal intensity and electricity intensity are also modeled to reveal energy transition dynamics driven by urbanization. A set of newly developed regression techniques, namely well-performed common correlated effects mean group (CCEMG) and augmented mean group (AMG) estimators, are used to treat residual cross-sectional dependence, nonstationary residuals, and unlikely-to-hold homogeneous slope assumptions. The results obtained verify that the net effects of urbanization on overall energy intensity and electricity intensity are statistically positive, with long-run elasticities of 0.14% to 0.37% and 0.23% to 0.29%, respectively, whereas China's urbanization does not significantly increase coal intensity. The fact that short-run elasticities account for a majority of corresponding long-run values indicates that the short-run effect, that is, indirect energy use induced by urban infrastructures is the most significant impact channel of urbanization on energy use in China. An energy transition from high-pollution coal to clean electricity is also present in China, although the fundamental transition to renewable energy is still in its infancy. From a regional perspective, urbanization exerts asymmetric impacts on provincial energy use so that energy policies associated with urbanization should be province-specific. The findings also illustrate that for a panel dataset on regional dimension within large and fast-growing economies such
Graphene nanoribbon as an elastic damper
Evazzade, Iman; Lobzenko, Ivan P.; Saadatmand, Danial; Korznikova, Elena A.; Zhou, Kun; Liu, Bo; Dmitriev, Sergey V.
2018-05-01
Heterostructures composed of dissimilar two-dimensional nanomaterials can have nontrivial physical and mechanical properties which are potentially useful in many applications. Interestingly, in some cases, it is possible to create heterostructures composed of weakly and strongly stretched domains with the same chemical composition, as has been demonstrated for some polymer chains, DNA, and intermetallic nanowires supporting this effect of two-phase stretching. These materials, at relatively strong tension forces, split into domains with smaller and larger tensile strains. Within this region, average strain increases at constant tensile force due to the growth of the domain with the larger strain, at the expense of the domain with smaller strain. Here, the two-phase stretching phenomenon is described for graphene nanoribbons with the help of molecular dynamics simulations. This unprecedented feature of graphene that is revealed in our study is related to the peculiarities of nucleation and the motion of the domain walls separating the domains of different elastic strain. It turns out that the loading–unloading curves exhibit a hysteresis-like behavior due to the energy dissipation during the domain wall nucleation and motion. Here, we put forward the idea of implementing graphene nanoribbons as elastic dampers, efficiently converting mechanical strain energy into heat during cyclic loading–unloading through elastic extension where domains with larger and smaller strains coexist. Furthermore, in the regime of two-phase stretching, graphene nanoribbon is a heterostructure for which the fraction of domains with larger and smaller strain, and consequently its physical and mechanical properties, can be tuned in a controllable manner by applying elastic strain and/or heat.
Czech Academy of Sciences Publication Activity Database
Poživilová, Alena; Plešek, Jiří
2005-01-01
Roč. 482, č. 482 (2005), s. 327-330 ISSN 0255-5476 R&D Projects: GA ČR(CZ) GA101/03/0331; GA ČR(CZ) GP106/03/D038 Institutional research plan: CEZ:AV0Z20760514 Keywords : acoustoelasticity * large strains * third order elastic moduli Subject RIV: JG - Metallurgy Impact factor: 0.399, year: 2005
International Nuclear Information System (INIS)
Popov, N.N.; Panchenko, A.M.; Sevryugina, I.V.; Novikov, S.A.
2002-01-01
The data are obtained for the influence of preliminary plastic deformation of titanium nickelide in an austenitic state on the character of its elastic properties variation during various type phase transitions. It is shown that the defect structure evolution occurring as a result of shock wave loading has a combined ambiguous effect on microstructural mechanisms being the basis for martensitic phase transformations. Shock wave loading is stated to stimulate the dislocation-displacement mechanism of R-phase formation and to increase the stability of R-phase to R→B19'-transition [ru
Continuum mechanics elasticity, plasticity, viscoelasticity
Dill, Ellis H
2006-01-01
FUNDAMENTALS OF CONTINUUM MECHANICSMaterial ModelsClassical Space-TimeMaterial BodiesStrainRate of StrainCurvilinear Coordinate SystemsConservation of MassBalance of MomentumBalance of EnergyConstitutive EquationsThermodynamic DissipationObjectivity: Invariance for Rigid MotionsColeman-Mizel ModelFluid MechanicsProblems for Chapter 1BibliographyNONLINEAR ELASTICITYThermoelasticityMaterial SymmetriesIsotropic MaterialsIncompressible MaterialsConjugate Measures of Stress and StrainSome Symmetry GroupsRate Formulations for Elastic MaterialsEnergy PrinciplesGeometry of Small DeformationsLinear ElasticitySpecial Constitutive Models for Isotropic MaterialsMechanical Restrictions on the Constitutive RelationsProblems for Chapter 2BibliographyLINEAR ELASTICITYBasic EquationsPlane StrainPlane StressProperties of SolutionsPotential EnergySpecial Matrix NotationThe Finite Element Method of SolutionGeneral Equations for an Assembly of ElementsFinite Element Analysis for Large DeformationsProblems for Chapter 3Bibliograph...
Energy evolution of the large-t elastic scattering and its correlation with multiparticle production
International Nuclear Information System (INIS)
Troshin, S. M.
2013-01-01
It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep-elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle production processes.
Energy evolution of the large-t elastic scattering and its correlation with multiparticle production
Energy Technology Data Exchange (ETDEWEB)
Troshin, S. M. [Institute for High Energy Physics, Protvino, Moscow Region, 142281 (Russian Federation)
2013-04-15
It is emphasized that the collective dynamics associated with color confinement is dominating over a point-like mechanism related to a scattering of the proton constituents at the currently available values of the momentum transferred in proton elastic scattering at the LHC. Deep-elastic scattering and its role in the dissimilation of the absorptive and reflective asymptotic scattering mechanisms are discussed with emphasis on the experimental signatures associated with the multiparticle production processes.
International Nuclear Information System (INIS)
Pierrard, J.; Bruneton, C.; Bystricky, J.; Cozzika, G.; Deregel, J.; Ducros, Y.; Gaidot, A.; Khantine-Langlois, F.; Lehar, F.; Lesquen, A. de; Merlo, J.P.; Miyashita, S.; Movchet, J.; Raoul, J.C.; Van Rossum, L.; Kanavets, V.P.
1975-01-01
The spin rotation parameter R in pp and π + p elastic scattering at 45GeV/c has been measured at the Serpukhov accelerator, for /t/ ranging from 0.2 to 0.5(GeV/c) 2 . The results are presented, together with previous R measurements at 3.8, 6, 16 and 40GeV/c, and are compared with the predictions of Regge pole models. The equality of the values for R in proton-proton and pion-proton scattering, within the experimental errors, is a test of factorization of the residues. An s-channel helicity amplitude analysis for pion-nucleon scattering at 40GeV/c is made using all available data. Significant results are obtained for the non flip amplitude in isoscalar exchange and for flip amplitudes on both isovector and isoscalar exchanges. The helicity flip in isoscalar exchange is non negligible. The energy dependence of this amplitude, at 6, 16 and 40GeV/c, is compared with predictions of Regge pole models [fr
Low-energy elastic-scattering of alpha particles from [sup 34]S, [sup 50]Cr and [sup 62]Ni
Energy Technology Data Exchange (ETDEWEB)
Bredbacka, AA. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Brenner, M. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Kaellman, K.-M. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Manngaard, P. (Department of Physics, AAbo Akademi, 20500 AAbo (Finland)); Mate, Z. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary)); Szilagyi, S. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary)); Zolnai, L. (Institute of Nuclear Research of the Hungarian Academy of Sciences, H-4001 Debrecen Pf. 51 (Hungary))
1994-07-11
Angular distributions of elastically scattered alpha particles were measured for the [sup 34]S, [sup 50]Cr and [sup 62]Ni target nuclei in the energy range 12.8-20.0 MeV. The experimental data were analysed using the phenomenological optical model with the Saxon-Woods form factor; in the case of [sup 34]S the squared Saxon-Woods form factor was also applied. Phenomena such as the anomalous energy dependence of the potential near the Coulomb barrier, the discrete ambiguity problem, the low-mass and low-energy limit of applicability of the optical model are discussed using the real volume integral values obtained. ((orig.))
Limão-Vieira, P.; Horie, M.; Kato, H.; Hoshino, M.; Blanco, F.; García, G.; Buckman, S. J.; Tanaka, H.
2011-12-01
We report absolute elastic differential, integral and momentum transfer cross sections for electron interactions with CCl4. The incident electron energy range is 1.5-100 eV, and the scattered electron angular range for the differential measurements varies from 15°-130°. The absolute scale of the differential cross section was set using the relative flow technique with helium as the reference species. Comparison with previous total cross sections shows good agreement. Atomic-like behaviour in this scattering system is shown here for the first time, and is further investigated by comparing the CCl4 elastic cross sections to recent results on the halomethanes and atomic chlorine at higher impact energies [H. Kato, T. Asahina, H. Masui, M. Hoshino, H. Tanaka, H. Cho, O. Ingólfsson, F. Blanco, G. Garcia, S. J. Buckman, and M. J. Brunger, J. Chem. Phys. 132, 074309 (2010)], 10.1063/1.3319761.
Gao, Longfei
2018-02-22
We consider numerical simulation of the isotropic elastic wave equations arising from seismic applications with non-trivial land topography. The more flexible finite element method is applied to the shallow region of the simulation domain to account for the topography, and combined with the more efficient finite difference method that is applied to the deep region of the simulation domain. We demonstrate that these two discretization methods, albeit starting from different formulations of the elastic wave equation, can be joined together smoothly via weakly imposed interface conditions. Discrete energy analysis is employed to derive the proper interface treatment, leading to an overall discretization that is energy-conserving. Numerical examples are presented to demonstrate the efficacy of the proposed interface treatment.
Gao, Longfei; Keyes, David E.
2018-01-01
We consider numerical simulation of the isotropic elastic wave equations arising from seismic applications with non-trivial land topography. The more flexible finite element method is applied to the shallow region of the simulation domain to account for the topography, and combined with the more efficient finite difference method that is applied to the deep region of the simulation domain. We demonstrate that these two discretization methods, albeit starting from different formulations of the elastic wave equation, can be joined together smoothly via weakly imposed interface conditions. Discrete energy analysis is employed to derive the proper interface treatment, leading to an overall discretization that is energy-conserving. Numerical examples are presented to demonstrate the efficacy of the proposed interface treatment.
Energy Technology Data Exchange (ETDEWEB)
Anderson, E. K.; Boadle, R. A.; Machacek, J. R.; Makochekanwa, C.; Sullivan, J. P. [ARC Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Chiari, L. [ARC Centre for Antimatter-Matter Studies, Flinders University, GPO Box 2100, Adelaide, 5001 SA (Australia); Buckman, S. J., E-mail: Stephen.buckman@anu.edu.au [ARC Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra 0200 (Australia); Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Brunger, M. J. [ARC Centre for Antimatter-Matter Studies, Flinders University, GPO Box 2100, Adelaide, 5001 SA (Australia); Institute of Mathematical Sciences, University of Malaya, Kuala Lumpur (Malaysia); Garcia, G. [Instituto de Fısica Fundamental, Consejo Superior de Investigationes Cientıficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain); Blanco, F. [Departamento de Fısica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain); Ingolfsson, O. [Department of Chemistry, Science Institute, University of Iceland, Reykjavík 107 (Iceland)
2014-07-21
Measurements of the grand total and total positronium formation cross sections for positron scattering from uracil have been performed for energies between 1 and 180 eV, using a trap-based beam apparatus. Angular, quasi-elastic differential cross section measurements at 1, 3, 5, 10, and 20 eV are also presented and discussed. These measurements are compared to existing experimental results and theoretical calculations, including our own calculations using a variant of the independent atom approach.
International Nuclear Information System (INIS)
Troiano, A.R.
1975-12-01
Homogeneous deformation of type 310 austenitic stainless steel only slightly influenced the corrosion potential in a boiling 3 percent NaCl aqueous environment. The difference in a deaerated solution was of the order of 25 mV and somewhat more for an aerated solution. Elastic strains appeared to have little or no influence on the corrosion potential for fully annealed as well as 10 percent and 25 percent homogeneously deformed 310 steel. Oxygen in the environment shifted the corrosion potential several hundred millivolts in the less active direction. The critical cracking potential in a deaerated 3 percent NaCl solution was approximately the same for the annealed and homogeneously deformed specimens at approximately -125 mV SCE
Energy Technology Data Exchange (ETDEWEB)
Gauron, Pierre; Basarab Nicolescu [Theoretical Physics Division, Inst. de Physique Nucleaire, Paris-11 Univ., 91 - Orsay (France); Leader Elliot [Birkbeck College, Malet Street, London WCIE 7HX (United Kingdom)
1999-10-01
We generalize a relation proposed recently by Giffon, Predazzi and Samokhin, linked to the behaviour of elastic scattering at asymptotically high energies. We demonstrate that their result, established within a limited class of possible asymptotic behaviour, is actually very general and can be proved in an essentially axiomatic framework. We discuss how this relation can be used as a basis for detecting new phenomena at RHIC and LHC energies. (authors)
International Nuclear Information System (INIS)
Singh, R.N.; Stahle, P.; Sairam, K.; Ristmana, Matti; Banerjee, S.
2008-01-01
The objective of the present investigation is to predict the habit plane of δ-hydride precipitating in α-Zr at 25 and 300 deg C using strain energy minimization technique. The δ-hydride phase is modeled to undergo isotropic elastic and plastic deformation. The α-Zr phase was modeled to undergo transverse isotropic elastic deformation. Both isotropic plastic and transverse isotropic plastic deformations of α-Zr were considered. Further, both perfect and linear work-hardening plastic behaviors of zirconium and its hydride were considered. Accommodation strain energy of δ-hydrides forming in α-Zr crystal was computed using initial strain method as a function of hydride nuclei orientation. Hydride was modeled as disk with circular edge. The simulation was carried out using materials properties reported at 25 and 300 deg C. Contrary to several habit planes reported in literature for δ-hydrides precipitating in α-Zr crystal the total accommodation energy minima suggests only basal plane i.e. (0001) as the habit plane. (author)
Evolution of soft-phonon modes in Fe-Pd shape memory alloy under large elastic-like strains
Czech Academy of Sciences Publication Activity Database
Seiner, Hanuš; Stoklasová, Pavla; Sedlák, Petr; Ševčík, Martin; Janovská, Michaela; Landa, Michal; Fukuda, T.; Yamaguchi, T.; Kakeshita, T.
2016-01-01
Roč. 105, Februar (2016), s. 182-188 ISSN 1359-6454 R&D Projects: GA ČR GA14-15264S Institutional support: RVO:61388998 Keywords : anisotropic elasticity * single crystal * phase transitions * surface acoustic waves (SAW) Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 5.301, year: 2016 http://ac.els-cdn.com/S1359645415301348/1-s2.0-S1359645415301348-main.pdf?_tid=1309c656-fb07-11e5-888b-00000aab0f01&acdnat=1459844530_9f54d29d7437d07cc7b3dae3fbb0a882
Guerrero-López, Carlos M; Unar-Munguía, Mishel; Colchero, M Arantxa
2017-02-10
Chile is the second world's largest per capita consumer of caloric beverages. Caloric beverages are associated with overweight, obesity and other chronic diseases. The objective of this study is to estimate the price elasticity of demand for soft drinks, other sugar-sweetened beverages and high-energy dense foods in urban areas in Chile in order to evaluate the potential response of households' consumption to changes in prices. We used microdata from the VII Family Budget Survey 2012-2013, which collects information on expenditures made by Chilean urban households on items such as beverages and foods. We estimated a Linear Approximation of an Almost Ideal Demand System Model to derive own and cross price elasticities of milk, coffee, tea and other infusions, plain water, soft drinks, other flavored beverages, sweet snacks, sugar and honey, and desserts. We considered the censored nature of the data and included the Inverse Mills Ratio in each equation of the demand system. We estimated a Quadratic Almost Ideal Demand System and a two-part model as sensitivity analysis. We found an own price-elasticity of -1.37 for soft drinks. This implies that a price increase of 10% is associated with a reduction in consumption of 13.7%. We found that the rest of food and beverages included in the demand system behave as substitutes for soft drinks. For instance, plain water showed a cross-price elasticity of 0.63: a 10% increase in price of soft drinks could lead to an increase of 6.3% of plain water. Own and cross price elasticities were similar between models. The demand of soft drinks is price sensitive among Chilean households. An incentive system such as subsidies to non-sweetened beverages and tax to soft drinks could lead to increases in the substitutions for other healthier beverages.
Directory of Open Access Journals (Sweden)
Carlos M. Guerrero-López
2017-02-01
Full Text Available Abstract Background Chile is the second world’s largest per capita consumer of caloric beverages. Caloric beverages are associated with overweight, obesity and other chronic diseases. The objective of this study is to estimate the price elasticity of demand for soft drinks, other sugar-sweetened beverages and high-energy dense foods in urban areas in Chile in order to evaluate the potential response of households’ consumption to changes in prices. Methods We used microdata from the VII Family Budget Survey 2012–2013, which collects information on expenditures made by Chilean urban households on items such as beverages and foods. We estimated a Linear Approximation of an Almost Ideal Demand System Model to derive own and cross price elasticities of milk, coffee, tea and other infusions, plain water, soft drinks, other flavored beverages, sweet snacks, sugar and honey, and desserts. We considered the censored nature of the data and included the Inverse Mills Ratio in each equation of the demand system. We estimated a Quadratic Almost Ideal Demand System and a two-part model as sensitivity analysis. Results We found an own price-elasticity of −1.37 for soft drinks. This implies that a price increase of 10% is associated with a reduction in consumption of 13.7%. We found that the rest of food and beverages included in the demand system behave as substitutes for soft drinks. For instance, plain water showed a cross-price elasticity of 0.63: a 10% increase in price of soft drinks could lead to an increase of 6.3% of plain water. Own and cross price elasticities were similar between models. Conclusions The demand of soft drinks is price sensitive among Chilean households. An incentive system such as subsidies to non-sweetened beverages and tax to soft drinks could lead to increases in the substitutions for other healthier beverages.
Low energy 16O+208Pb elastic scattering: an attempt to analyze the microscopic effective potential
International Nuclear Information System (INIS)
Mau, N.V.; Ferrero, J.L.; Pacheco, J.C.; Bilwes, B.
1991-03-01
Elastic scattering of 16 O on 208 Pb is studied at 96, 104, 129.5, 192, 216.6 and 312.6 MeV. The 16 O+ 208 Pb potential is calculated first in the closure approximation model and compared to semi-phenomenological potentials. Then detailed contributions to the polarization real potential and to the imaginary potential due to the coupling of the elastic channels to the inelastic channels are calculated. The results are compared to the authors' model potential and used to test the main assumptions of the model. From that comparison a qualitative interpretation of the success of the model is proposed. At last the elastic scattering cross sections are calculated and compared to the data. (author) 41 refs., 6 figs., 5 tabs
Directory of Open Access Journals (Sweden)
Schlömerkemper Anja
2015-01-01
Full Text Available A major open problem in the mathematical analysis of martensitic phase transformations is the derivation of explicit formulae for the set of recoverable strains and for the relaxed energy of the system. These are governed by the mathematical notion of quasiconvexity. Here we focus on bounds on these quasiconvex hulls and envelopes in the setting of geometrically-linear elasticity. Firstly, we will present mathematical results on triples of transformation strains. This yields further insight into the quasiconvex hull of the twelve transformation strains in cubic-to-monoclinic phase transformations. Secondly, we consider bounds on the energy of such materials based on the so-called energy of mixing thus obtaining a lamination upper bound on the quasiconvex envelope of the energy. Here we present a new algorithm that yields improved upper bounds and allows us to relate numerical results for the lamination upper bound on the energy with theoretical inner bounds on the quasiconvex hull of triples of transformation strains.
Energy Technology Data Exchange (ETDEWEB)
Wielunski, L S [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics
1997-12-31
The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.
Energy Technology Data Exchange (ETDEWEB)
Wielunski, L.S. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Lindfield, NSW (Australia). Div. of Applied Physics
1996-12-31
The sensitivity of hydrogen elastic recoil detection ( ERD ) is usually limited by the low energy background in the ERD spectrum. A number of 4.5 MeV He{sup ++} hydrogen ERD spectra from different hydrogen implanted samples are compared. The samples are chosen with different atomic numbers from low Z (carbon) to high Z (tungsten carbide) to observe the effects of multiple scattering and double scattering within the sample material. The experimental depth resolution and levels of the low energy background in ERD spectra are compared with theoretical predictions from multiple and double scattering. 10 refs., 2 tabs., 5 figs.
Study of the elastic scattering of {sup 6}He on {sup 208}Pb at energies around the Coulomb barrier
Energy Technology Data Exchange (ETDEWEB)
Sanchez-Benitez, A.M. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Escrig, D. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Alvarez, M.A.G.; Andres, M.V. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Angulo, C. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Borge, M.J.G. [Instituto de Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Cabrera, J. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Cherubini, S. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Demaret, P. [Centre de Recherches du Cyclotron, Universite Catholique de Louvain, B-1348 Louvain-la-Neuve (Belgium); Espino, J.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Figuera, P. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Freer, M. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Garcia-Ramos, J.E. [Departamento de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain); Gomez-Camacho, J. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain); Gulino, M. [INFN Laboratori Nazionali del Sud, I-95123 Catania (Italy); Kakuee, O.R. [Van der Graaff Laboratory, Nuclear Research Centre, AEOI, PO Box 14155-1339, Tehran (Iran, Islamic Republic of); Martel, I. [Dept. de Fisica Aplicada, Universidad de Huelva, E-21071 Huelva (Spain)], E-mail: imartel@uhu.es; Metelko, C. [School of Physics and Astronomy, University of Birmingham, B15 2TT Birmingham (United Kingdom); Moro, A.M. [Dept. de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, E-41080 Sevilla (Spain)] (and others)
2008-04-15
The elastic scattering of {sup 6}He on {sup 208}Pb has been measured at laboratory energies of 14, 16, 18 and 22 MeV. These data were analyzed using phenomenological Woods-Saxon form factors and optical model calculations. A semiclassical polarization potential was used to study the effect of the Coulomb dipole polarizability. Evidence for long range absorption, partially arising from Coulomb dipole polarizability, is reported. The energy variation of the optical potential was found to be consistent with the dispersion relations which connect the real and imaginary parts of the potential.
Martensitic textures: Multiscale consequences of elastic compatibility
International Nuclear Information System (INIS)
Shenoy, S.R.; Lookman, T.; Saxena, A.; Bishop, A.R.
2001-03-01
We show that a free energy entirely in the order-parameter strain variable(s), rather than the displacement field, provides a unified understanding of martensitic textures. We use compatibility equations, linking the strain tensor components in the bulk and at interfaces, that induce anisotropic order-parameter strain interactions. These two long-range bulk/interface potentials, together with local compositional fluctuations, drive the formation of global elastic textures. Relaxational simulations show the spontaneous formation (and evolution under stress/temperature quenches) of equal width parallel twins, branched twins, and tweed, including characteristic scaling of twin width with twin length. (author)
Elasticity theory and applications
Saada, Adel S; Hartnett, James P; Hughes, William F
2013-01-01
Elasticity: Theory and Applications reviews the theory and applications of elasticity. The book is divided into three parts. The first part is concerned with the kinematics of continuous media; the second part focuses on the analysis of stress; and the third part considers the theory of elasticity and its applications to engineering problems. This book consists of 18 chapters; the first of which deals with the kinematics of continuous media. The basic definitions and the operations of matrix algebra are presented in the next chapter, followed by a discussion on the linear transformation of points. The study of finite and linear strains gradually introduces the reader to the tensor concept. Orthogonal curvilinear coordinates are examined in detail, along with the similarities between stress and strain. The chapters that follow cover torsion; the three-dimensional theory of linear elasticity and the requirements for the solution of elasticity problems; the method of potentials; and topics related to cylinders, ...
Energy Technology Data Exchange (ETDEWEB)
Morcelle, V.; Lichtenthaeler, R.; Guimaraes, V.; Lepine-Szily, A.; Faria, P.N.; Camargo, O.; Barioni, A.; Mendes Junior, D.R.; Condori, R.P.; Zamora, J.C.; Morais, M.C.; Pires, K.C.C.; Scarduelli, V.; Leistenschneider, E.; Zagatto, V.A.B. [Universidade de Sao Paulo (USP), SP (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)
2011-07-01
Full text: Elastic scattering angular distributions and total reaction cross sections of the neutron halo projectile nucleus {sup 6}He on a {sup 58}Ni target at energies around the Coulomb barrier are presented. The measurements were obtained at pelletron accelerator at the University of Sao Paulo (Brazil) and the {sup 6}He radioactive secondary beam has been produced in the RIBRAS system through the {sup 9}Be({sup 7}Li, {sup 6}He){sup 10}B production reaction. The elastic scattering angular distributions obtained at E{sub Lab}= 12.5, 16.5 and 21.0 MeV, have been analysed by using optical model, using the Sao Paulo and Wood-Saxon potentials and the respective total reaction cross sections have been obtained. The total reaction cross sections have been reduced using the Wong formula and the UFF equation and are compared with other stable and unstable systems from the literature. (author)
Energy dependence of the analyzing power Ayo in the anti p p elastic scattering
International Nuclear Information System (INIS)
Bertini, R.
1991-01-01
The analysing power data A yo of the anti p p elastic scattering at six beam momenta from P lab = 439 MeV/c up to 988 MeV/c are plotted as a function of In(-t). The regularities shown by the data are discussed
A closed analytic form for p-d elastic scattering at high energy
International Nuclear Information System (INIS)
Li, Y.; Lo, S.
1983-01-01
Using a simple harmonic oscillator wave function for deuteron it is possible to give an analytic solution in closed form for p-d elastic scattering. It has the advantage of displaying clearly all the contributions separately (D-wave, spin flip etc.). It can also fit experimental data
Nuclear and partonic dynamics in high energy elastic nucleus-nucleus scattering
International Nuclear Information System (INIS)
Malecki, A.
1991-01-01
A hybrid description of diffraction which combines a geometrical modelling of multiple scattering with many-channel effects resulting from intrinsic dynamics on nuclear and sub-nuclear level is presented. The application to the 4 He- 4 He elastic scattering is very satisfactory. Our analysis suggests that at large momentum transfers the parton constituents of nucleons immersed in nuclei are deconfined. (author)
International Nuclear Information System (INIS)
Shahram Shahrooi; Ibrahim Henk Metselaar; Zainul Huda; Ghezavati, H.R.
2009-01-01
Full text: In this study, the plastic strain energy under multiaxial fatigue condition has been calculated in the cyclic plasticity models by the stress-strain hysteresis loops. Then, using the results of these models, the fatigue lives in energy-based fatigue model is predicted and compared to experimental data. Moreover, a weighting factor on shear plastic work is presented to decrease the life factors in the model fatigue. (author)
Strain Energy Density in the Elastodynamics of the Spacetime Continuum and the Electromagnetic Field
Directory of Open Access Journals (Sweden)
Millette P. A.
2013-04-01
Full Text Available We investigate the strain energy density of the spacetime continuum in the Elasto- dynamics of the Spacetime Continuum by applying continuum m echanical results to strained spacetime. The strain energy density is a scalar. W e find that it is separated into two terms: the first one expresses the dilatation energy density (the “mass” longitu- dinal term while the second one expresses the distortion en ergy density (the “massless” transverse term. The quadratic structure of the energy rel ation of Special Relativity is found to be present in the theory. In addition, we find that the kinetic energy pc is car- ried by the distortion part of the deformation, while the dil atation part carries only the rest-mass energy. The strain energy density of the electrom agnetic energy-momentum stress tensor is calculated. The dilatation energy density (the rest-mass energy density of the photon is found to be 0 as expected. The transverse dis tortion energy density is found to include a longitudinal electromagnetic energy fl ux term, from the Poynting vector, that is massless as it is due to distortion, not dilatation, of the spacetime con- tinuum. However, because this energy flux is along the direct ion of propagation (i.e. longitudinal, it gives rise to the particle aspect of the el ectromagnetic field, the photon.
Elastic scattering of 7Li + 27Al at several angles in the 7-11 MeV energy range
International Nuclear Information System (INIS)
Abriola, D.; Carnelli, P.; Arazi, A.; Figueira, J.M.; Capurro, O.A.; Cardona, M.A.; Fernandez Niello, J.O.; Hojman, D.; Fimiani, L.; Grinberg, P.; Martinez Heimann, D.; Marti, G.V.; Negri, A.E.; Pacheco, A.J.
2010-01-01
Elastic cross sections for the 7 Li + 27 Al system were measured at laboratory energies between 7 and 11 MeV in steps of 0.25 MeV, and angles between 135 o and 170 o in steps of 5 o . Excitation functions for the elastic scattering were measured using an array of eight Si surface-barrier detectors whereas a solid-state telescope was used to estimate and subtract background from other reactions. Contamination from α particles arising from the 7 Li breakup process at E lab ≥ 10 MeV makes the use of these energies inadvisable for RBS applications. The present results are compared with previous data obtained at 165 o (E lab ≤ 6 MeV), 140 o and 170 o (E lab ≤ 8 MeV). The experimental data were analyzed in terms of the Optical Model. Two different energy-independent potentials were found. These optical potentials allow an interpolation with physical meaning to other energies and scattering angles. The experimental cross sections will be uploaded to the IBANDL database.
International Nuclear Information System (INIS)
Francois, D.
1975-01-01
The study of potential energy variations in a loaded elastic solid containing a crack leads to determination of the crack driving force G. Generalization of this concept to cases other than linear elasticity leads to definition of the integral J. In a linear solid, the crack tip stress field is characterized by a single parameter: the stress-intensity factor K. When the crack tip plastic zone size is confined to the elastic singularity J=G, it is possible to establish relationship between these parameters and plastic strain (and in particular the crack tip opening displacement delta). The stress increases because of the triaxiality effect. This overload rises with increasing strain hardening. When the plastic zone size expands, using certain hypotheses, delta can be calculated. The plastic strain intensity is exclusively dependent on parameter J [fr
Elastic scattering of polarized deuterons from 40Ca and 58Ni at intermediate energies
International Nuclear Information System (INIS)
Sen, N. van; Arvieux, J.; Yanlin, Y.; Gaillard, G.; Bonin, B.; Boudard, A.; Bruge, G.; Lugol, J.C.; Babinet, R.; Hasegawa, T.; Soga, F.; Cameron, J.M.; Neilson, G.C.; Sheppard, D.M.
1985-01-01
Angular distributions of cross section, and Asub(y) and Asub(yy) analyzing powers were measured for polarized deuteron elastic scattering from 58 Ni at 200, 400 and 700 MeV, and 40 Ca at 700 MeV. Phenomenological potentials were obtained from an optical model analysis of the data. The total reaction cross sections deduced were compared to predictions from the Glauber theory optical limit. (orig.)
Energy Technology Data Exchange (ETDEWEB)
Arretche, F. [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, Santa Catarina (Brazil)], E-mail: farretche@hotmail.com; Mazon, K.T.; Michelin, S.E. [Departamento de Fisica, Universidade Federal de Santa Catarina, 88040-900, Florianopolis, Santa Catarina (Brazil); Fujimoto, M.M. [Departamento de Fisica, Universidade Federal do Parana, 81531-990, Curitiba, Parana (Brazil); Iga, I.; Lee, M.-T. [Departamento de Quimica, Universidade Federal de Sao Carlos, 13565-905, Sao Paulo (Brazil)
2008-02-15
Iterative Schwinger variational methods and the method of continued fractions, widely used for electron-molecule scattering, are applied for the first time to investigate positron-molecule interactions. Specifically, integral and differential cross sections for elastic positron scattering by CO in the (0.5-20) eV energy range are calculated and reported. In our calculation, a static plus correlation-polarization potential is used to represent the collisional dynamics. Our calculated results are in general agreement with the theoretical and experimental data available in the literature.
Nonlocal elasticity tensors in dislocation and disclination cores
International Nuclear Information System (INIS)
Taupin, V.; Gbemou, K.; Fressengeas, C.; Capolungo, L.
2017-01-01
We introduced nonlocal elastic constitutive laws for crystals containing defects such as dislocations and disclinations. Additionally, the pointwise elastic moduli tensors adequately reflect the elastic response of defect-free regions by relating stresses to strains and couple-stresses to curvatures, elastic cross-moduli tensors relating strains to couple-stresses and curvatures to stresses within convolution integrals are derived from a nonlocal analysis of strains and curvatures in the defects cores. Sufficient conditions are derived for positive-definiteness of the resulting free energy, and stability of elastic solutions is ensured. The elastic stress/couple stress fields associated with prescribed dislocation/disclination density distributions and solving the momentum and moment of momentum balance equations in periodic media are determined by using a Fast Fourier Transform spectral method. Here, the convoluted cross-moduli bring the following results: (i) Nonlocal stresses and couple stresses oppose their local counterparts in the defects core regions, playing the role of restoring forces and possibly ensuring spatio-temporal stability of the simulated defects, (ii) The couple stress fields are strongly affected by nonlocality. Such effects favor the stability of the simulated grain boundaries and allow investigating their elastic interactions with extrinsic defects, (iii) Driving forces inducing grain growth or refinement derive from the self-stress and couple stress fields of grain boundaries in nanocrystalline configurations.
Analyses of Alpha-Alpha Elastic Scattering Data in the Energy Range 140 - 280 MeV
Energy Technology Data Exchange (ETDEWEB)
Shehadeh, Zuhair F. [Taif University, Taif (Saudi Arabia)
2017-01-15
The differential and the reaction cross-sections for 4He-4He elastic scattering data have been nicely obtained at four energies ranging from 140 MeV to 280 MeV (lab system), namely, 140, 160, 198 and 280 MeV, by using a new optical potential with a short-range repulsive core. The treatment has been handled relativistically as υ/c > 0.25 for the two lower energies and υ/c > 0.31 for the two higher ones. In addition to explaining the elastic angular distributions, the adopted potentials accounted for the structure that may exist at angles close to 90◦ , especially for the 198 and the 280-MeV incident energies. No renormalization has been used, and all our potential parameters are new. The necessity of including a short-range repulsive potential term in our real nuclear potential part has been demonstrated. Our results contribute to solving a long-standing problem concerning the nature of the alpha-alpha potential. This is very beneficial in explaining unknown alpha-nucleus and nucleus-nucleus relativistic reactions by using the cluster formalism.
Energy Technology Data Exchange (ETDEWEB)
Farag, M.Y.H.; Esmael, E.H. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Maridi, H.M. [Cairo University, Physics Department, Faculty of Science, Giza (Egypt); Taiz University, Physics Department, Faculty of Applied Science, Taiz (Yemen)
2012-11-15
The proton elastic scattering data on some light exotic nuclei, namely, {sup 6,} {sup 8}He, {sup 9,} {sup 11}Li, and {sup 10,} {sup 11,} {sup 12}Be, at energies below than 100MeV/nucleon are analyzed using the single folding optical model. The real, imaginary, and spin-orbit parts of the optical potential (OP) are constructed only from the folded potentials and their derivatives using M3Y effective nucleon-nucleon interaction. These OP parts, their renormalization factors and their volume integrals are studied. The surface and spin-orbit potentials are important to fit the experimental data. Three model densities for halo nuclei are used and the sensitivity of the cross-sections to these densities is tested. The imaginary OP within high-energy approximation is used and compared with the single folding OP. This OP with few and limited fitting parameters, which have systematic behavior with incident energy, successfully describes the proton elastic scattering data with exotic nuclei. (orig.)
Feng, Huifang
2013-05-31
The 〈112̄0〉 perfect dislocation in MgB2 is suggested to dissociate into two partial dislocations in an energy favorable way 〈112̄0〉 → 1/2 〈112̄0〉 + SF + 1/2 〈112̄0〉. This dissociation style is a correction of the previous dissociation 〈1000〉 → 1/3 〈11̄00〉 SF + 1/3 〈 2100〉proposed by Zhu et al. to model the partial dislocations and stacking fault observed by transmission electron microscopy. The latter dissociation results in a maximal stacking fault energy rather than a minimal one according to the generalized stacking fault energy calculated from first-principles methods. Furthermore, the elastic constants and anisotropy of MgB2 under different pressure are investigated. The core structures and mobilities of the 〈112̄0〉 dissociated dislocations are studied within the modified Peierls-Nabarro (P-N) dislocation theory. The variational method is used to solve the modified P-N dislocation equation and the Peierls stress is also determined under different pressure. High pressure effects on elastic anisotropy, core structure and Peierls stress are also presented. © 2013 Springer Science+Business Media New York.
Small-angle p--p elastic scattering at energies between 285 and 572 MeV
International Nuclear Information System (INIS)
Aebischer, D.; Favier, B.; Greeniaus, L.G.; Hess, R.; Junod, A.; Lechanoine, C.; Nikles, J.C.; Rapin, D.; Richard-Serre, C.; Werren, D.W.
1976-01-01
Differential cross sections for elastic p--p scattering have been measured at 285, 348, 398, 414, 455, 497, 530, and 572 MeV kinetic energy. The experiment was performed at the CERN synchrocyclotron, using multiwire proportional chambers placed directly in a proton beam. Scattering was observed for theta between approx. 15 and 10 0 in the laboratory system. The ratio α/sub p/ of the real and imaginary parts of the non-spin-flip nuclear forward amplitude was derived from the interference between the Coulomb and nuclear amplitudes. The values obtained are model dependent, but in this energy range α/sub p/ is positive and decreases with energy. Qualitatively good agreement with dispersion-relation predictions is observed
Intersubband energies in strain-compensated InGaN/AlInN quantum well structures
Energy Technology Data Exchange (ETDEWEB)
Park, Seoung-Hwan, E-mail: shpark@cu.ac.kr [Department of Electronics Engineering, Catholic University of Daegu, Hayang, Kyeongsan, Kyeongbuk, 712-702 (Korea, Republic of); Ahn, Doyeol [Institute of Quantum Information Processing and Systems, University of Seoul, 90 Jeonnong, Tongdaimoon-Gu, Seoul, Korea 130-743 (Korea, Republic of)
2016-01-15
Intersubband transition energies in the conduction band for strain-compensated InGaN/AlInN quantum well (QW) structures were investigated as a function of strain based on an effective mass theory with the nonparabolicity taken into account. In the case of an InGaN/AlInN QW structure lattice-matched to GaN, the wavelength is shown to be longer than 1.55 μm. On the other hand, strain-compensated QW structures show that the wavelength of 1.55 μm can be reached even for the QW structure with a relatively small strain of 0.3 %. Hence, the strain-compensated QW structures can be used for telecommunication applications at 1.55 μm with a small strain, compared to conventional GaN/AlN QW structure.
On the Landau-de Gennes Elastic Energy of a Q-Tensor Model for Soft Biaxial Nematics
Mucci, Domenico; Nicolodi, Lorenzo
2017-12-01
In the Landau-de Gennes theory of liquid crystals, the propensities for alignments of molecules are represented at each point of the fluid by an element Q of the vector space S_0 of 3× 3 real symmetric traceless matrices, or Q-tensors. According to Longa and Trebin (1989), a biaxial nematic system is called soft biaxial if the tensor order parameter Q satisfies the constraint tr(Q^2) = {const}. After the introduction of a Q-tensor model for soft biaxial nematic systems and the description of its geometric structure, we address the question of coercivity for the most common four-elastic-constant form of the Landau-de Gennes elastic free-energy (Iyer et al. 2015) in this model. For a soft biaxial nematic system, the tensor field Q takes values in a four-dimensional sphere S^4_ρ of radius ρ ≤ √{2/3} in the five-dimensional space S_0 with inner product = tr(QP). The rotation group it{SO}(3) acts orthogonally on S_0 by conjugation and hence induces an action on S^4_ρ \\subset {S}_0. This action has generic orbits of codimension one that are diffeomorphic to an eightfold quotient S^3/H of the unit three-sphere S^3, where H={± 1, ± i, ± j, ± k} is the quaternion group, and has two degenerate orbits of codimension two that are diffeomorphic to the projective plane RP^2. Each generic orbit can be interpreted as the order parameter space of a constrained biaxial nematic system and each singular orbit as the order parameter space of a constrained uniaxial nematic system. It turns out that S^4_ρ is a cohomogeneity one manifold, i.e., a manifold with a group action whose orbit space is one-dimensional. Another important geometric feature of the model is that the set Σ _ρ of diagonal Q-tensors of fixed norm ρ is a (geodesic) great circle in S^4_ρ which meets every orbit of S^4_ρ orthogonally and is then a section for S^4_ρ in the sense of the general theory of canonical forms. We compute necessary and sufficient coercivity conditions for the elastic energy by
Jamalpoor, A.; Ahmadi-Savadkoohi, A.; Hosseini-Hashemi, Sh
2016-10-01
This paper deals with the theoretical analysis of free vibration and biaxial buckling of magneto-electro-elastic (MEE) microplate resting on Kelvin-Voigt visco-Pasternak foundation and subjected to initial external electric and magnetic potentials, using modified strain gradient theory (MSGT). Kirchhoff plate model and Hamilton’s principle are employed to extract the governing equations of motion. Governing equations were analytically solved to obtain clear closed-form expression for complex natural frequencies and buckling loads using Navier’s approach. Numerical results are presented to reveal variations of natural frequency and buckling load ratio of MEE microplate against different amounts of the length scale parameter, initial external electric and magnetic potentials, aspect ratio, damping and transverse and shear stiffness parameters of the visco-Pasternak foundation, length to thickness ratio, microplate thickness and higher modes. Numerical results of this study illustrate that by increasing thickness-to-material length scale parameter ratio, both natural frequency and buckling load ratio predicted by MSGT and modified couple stress theory are reduced because the non-dimensional length scale parameter tends to decrease the stiffness of structures and make them more flexible. In addition, results show that initial external electric and initial external magnetic potentials have no considerable influence on the buckling load ratio and frequency of MEE microplate as the microplate thickness increases.
International Nuclear Information System (INIS)
Reshak, Ali H.; Jamal, Morteza
2012-01-01
Highlights: ► A new package for calculating elastic constants of orthorhombic structure is released. ► The package called ortho-elastic. ► It is compatible with [FP-(L)APW+lo] method implemented in WIEN2k code. ► Several orthorhombic structure compounds were used to test the new package. ► Elastic constants calculated using this package show good agreement with experiment. - Abstract: A new package for calculating the elastic constants of orthorhombic structure is released. The package called ortho-elastic. The formalism of calculating the ortho-elastic constants is described in details. The package is compatible with the highly accurate all-electron full-potential (linearized) augmented plane-wave plus local orbital [FP-(L)APW+lo] method implemented in WIEN2k code. Several orthorhombic structure compounds were used to test the new package. We found that the calculated elastic constants using the new package show better agreement with the available experimental data than the previous theoretical results used different methods. In this package the second-order derivative E ″ (ε) of polynomial fit E=E(ε) of energy vs strains at zero strain (ε=0), used to calculate the orthorhombic elastic constants.
Applicability of Martin close-quote s equations in high-energy elastic hadron scattering
International Nuclear Information System (INIS)
Kundrat, V.; Lokajicek, M.
1997-01-01
The validity region of Martin close-quote s equations enabling one to determine the t dependence of the real part of the elastic hadron amplitude from its imaginary part is critically reexamined. It can be concluded on the basis of a more precise analysis that quite unjustified and in principle incorrect physical results are obtained if the equations are used outside this region, i.e., for |t|approx-gt 0.15 GeV 2 . copyright 1997 The American Physical Society
The neutron elastic scatterirg differential cross sections in energy range below 440 keV
International Nuclear Information System (INIS)
Zo In Ok; Nikolenko, V.G.; Popov, A.B.; Samosvat, G.S.
1985-01-01
The intensities of elastically scattered neutrons have been measured on Ti, Ni, Fe, Zn, Ge, Se, Zr, Mo, Ru, Rh, Pd, Ag, Cd, 116 Sn, 117 Sn, 118 Sn, 119 Sn, 120 Sn, 122 Sn, 124 Sn, Te, Ta, W, Re targets at 45 deg, 90 deg and 135 deg angles on the IBR-30 reactor. The differential cross sections were descried by the formula σ(THETA)=σsub(s)/σ4π[1+ωsub(1)Psub(1)(cos THETA)+ωsub(2)Psub(2)(cos THETA)]. The tables on σsub(s)(E), ω 1 (E) and ω 2 (E) obtained from the experimental data are given
Elastic scattering of polarized neutrons by 3He at low energy
International Nuclear Information System (INIS)
Drigo, L.; Tornielli, G.; Zannoni, G.
1982-01-01
Elastic scattering by 3 He for 1.67, 2.43, 3.0, 3.4 and 7.8 MeV neutron beams of known polarization was measured at seven angles from 25 0 to 155 0 using a high pressure gas scintillation counter. The geometrical and multiple scattering effects were accounted for by the Monte Carlo technique. The corrected results were compared with previous experimental data and with the existing predictions based on microscopic calculations and phenomenological analyses. (author)
International Nuclear Information System (INIS)
Vucic, S.; Potvliege, R.M.; Joachain, C.J.; Louvain Univ., Louvain-la-Neuve
1987-01-01
We study the elastic scattering of electrons by the metastable states H(2s), He(2 1 S) and He(2 3 S) at intermediate energies within the framework of the third-order optical potential theory. The first-, second- and third-order contributions to the optical potential are analysed separately, and are compared with the corresponding quantities for e - H(1s) and e - He(1 1 S) elastic scattering. Results for positron impact scattering are also presented. (author)
Rodgers, Michael J.; Wen, Shengmin; Keer, Leon M.
2000-08-01
A three-dimensional quasi-static model of faulting in an elastic half-space with a horizontal change of material properties (i.e., joined elastic quarter spaces) is considered. A boundary element method is used with a stress drop slip zone approach so that the fault surface relative displacements as well as the free surface displacements are approximated in elements over their respective domains. Stress intensity factors and free surface displacements are calculated for a variety of cases to show the phenomenological behavior of faulting in such a medium. These calculations showed that the behavior could be distinguished from a uniform half-space. Slip in a stiffer material increases, while slip in a softer material decreases the energy release rate and the free surface displacements. Also, the 1989 Kalapana earthquake was located on the basis of a series of forward searches using this method and leveling data. The located depth is 8 km, which is the closer to the seismically inferred depth than that determined from other models. Finally, the energy release rate, which can be used as a fracture criterion for fracture at this depth, is calculated to be 11.1×106 J m-2.
Structural aspects of elastic deformation of a metallic glass
International Nuclear Information System (INIS)
Hufnagel, T. C.; Ott, R. T.; Almer, J.
2006-01-01
We report the use of high-energy x-ray scattering to measure strain in a Zr 57 Ti 5 Cu 20 Ni 8 Al 10 bulk metallic glass in situ during uniaxial compression in the elastic regime up to stresses of approximately 60% of the yield stress. The strains extracted in two ways--directly from the normalized scattering data and from the pair correlation functions--are in good agreement with each other for length scales greater than 4 A. The elastic modulus calculated on the basis of this strain is in good agreement with that reported for closely related amorphous alloys based on macroscopic measurements. The strain measured for atoms in the nearest-neighbor shell, however, is smaller than that for more distant shells, and the effective elastic modulus calculated from the strain on this scale is therefore larger, comparable to crystalline alloys of similar composition. These observations are in agreement with previously proposed models in which the nominally elastic deformation of a metallic glass has a significant anelastic component due to atomic rearrangements in topologically unstable regions of the structure. We also observe that the distribution of the atomic-level stresses in the glass becomes more uniform during loading. This implies that the stiffness of metallic glasses may have an entropic contribution, analogous to the entropic contribution in rubber elasticity
Elastic scattering of 16O+16O at energies E/A between 5 and 8 MeV
International Nuclear Information System (INIS)
Nicoli, M. P.; Haas, F.; Freeman, R. M.; Aissaoui, N.; Beck, C.; Elanique, A.; Nouicer, R.; Morsad, A.; Szilner, S.; Basrak, Z.
1999-01-01
The elastic scattering of 16 O+ 16 O has been measured at nine energies between E lab =75 and 124 MeV. The data cover up to 100 degree sign in the c.m. and can be described in terms of phenomenological and folding model potentials which reproduce the main features observed. In agreement with studies at higher energies in this and similar systems, refractive effects are present in the angular distributions at all energies. In particular, the passage of Airy minima through 90 degree sign at E c.m. =40, 47.5, and 62 MeV explains the deep minima observed in the excitation function. The real part of the optical potential is found to vary very little with energy over the studied interval, but the imaginary part shows a rapid change in its shape at incident energy about 90 MeV. Nonetheless, the energy dependence of the volume integral of the real and imaginary parts is in agreement with dispersion relation predictions. (c) 1999 The American Physical Society
International Nuclear Information System (INIS)
Ismail, Atef; Lee, Yen Cheong; Tammam, M.
2015-01-01
Proton elastic scattering at various incident energies is one method to study nuclear density distributions and nuclear radii. Single folding potential describing the p-scattering on 40 Ca over a broad energy range 9–48.4 MeV is constructed. The resulting potential does not need any renormalization to fit the measured elastic scattering angular distributions and total reaction cross-sections. Furthermore, correlation between volume integral and proton incident energy is discussed. Theoretical calculations are in a good agreement with existing experimental data. (author)
International Nuclear Information System (INIS)
Kudryavtsev, A.E.; Markushin, V.E.
1985-01-01
The experimental data on the low energy elastic p-barp scattering in the Coulomb-nuclear interference region and on the shift and width of the 1s level of p-barp-atom are analysed. The partial wave amplitudes for l=0.1 are extracted. The p-wave amplitude is in fair agreement with the atomic data for the 2p state and exhibits some energy structure. It is shown that the real-to-imaginary ratio of the p-barp forward elastic-scattering amplitude becomes negative in an energy interval just near p-barp-threshold
A nonlinear theory for elastic plates with application to characterizing paper properties
M. W. Johnson; Thomas J. Urbanik
1984-03-01
A theory of thin plates which is physically as well as kinematically nonlinear is, developed and used to characterize elastic material behavior for arbitrary stretching and bending deformations. It is developed from a few clearly defined assumptions and uses a unique treatment of strain energy. An effective strain concept is introduced to simplify the theory to a...
Role of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ
Bhattacharya, S.
2014-06-12
Perovskite-type SrTiO3-δ ceramics are multifunctional materials with significant potential as n-type thermoelectric (TE) materials. The electronic and thermal transport properties of spark plasma sintered polycrystalline Sr1-xYxTiO3-δ (x=0.05, 0.075, 0.1) ceramics are systematically investigated from (15-800) K. The Sr0.9Y0.1TiO3-δ simultaneously exhibits a large Seebeck coefficient, α>-80μV/K and moderately high electrical resistivity, ρ∼0.8mΩ-cm at a carrier concentration of ∼1021cm-3 at 300K resulting in a high TE power factor defined herein as (α2σT)∼0.84W/m-K at 760K. Despite the similar atomic masses of Sr (87.6g/mol) and Y (88.9g/mol), the lattice thermal conductivity (κL) of Sr1-xY xTiO3-δ is significantly reduced with increased Y-doping, owing to the smaller ionic radii of Y3+ (∼1.23Å, coordination number 12) compared to Sr2+ (∼1.44Å, coordination number 12) ions. In order to understand the thermal conductivity reduction mechanism, the κL in the Sr1-xY xTiO3-δ series are phenomenologically modeled with a modified Callaway\\'s equation from 30-600K. Phonon scattering by elastic strain field due to ionic radii mismatch is found to be the prominent scattering mechanism in reducing κL of these materials. In addition, the effect of Y-doping on the elastic moduli of Sr1-xY xTiO3-δ (x=0, 0.1) is investigated using resonant ultrasound spectroscopy, which exhibits an anomaly in x=0.1 in the temperature range 300-600K. As a result, the phonon mean free path is found to be further reduced in the Sr0.9Y0.1TiO3-δ compared to that of SrTiO3-δ, resulting in a considerably low thermal conductivity κ∼2.7W/m-K at 760K. Finally, we report a thermoelectric figure of merit (ZT)∼0.3 at 760K in the Sr0.9Y 0.1TiO3-δ, the highest ZT value reported in the Y-doped SrTiO3 ceramics thus far. © 2014 AIP Publishing LLC.
Role of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ
Bhattacharya, S.; Mehdizadeh Dehkordi, A.; Tennakoon, S.; Adebisi, R.; Gladden, J. R.; Darroudi, T.; Alshareef, Husam N.; Tritt, T. M.
2014-01-01
Perovskite-type SrTiO3-δ ceramics are multifunctional materials with significant potential as n-type thermoelectric (TE) materials. The electronic and thermal transport properties of spark plasma sintered polycrystalline Sr1-xYxTiO3-δ (x=0.05, 0.075, 0.1) ceramics are systematically investigated from (15-800) K. The Sr0.9Y0.1TiO3-δ simultaneously exhibits a large Seebeck coefficient, α>-80μV/K and moderately high electrical resistivity, ρ∼0.8mΩ-cm at a carrier concentration of ∼1021cm-3 at 300K resulting in a high TE power factor defined herein as (α2σT)∼0.84W/m-K at 760K. Despite the similar atomic masses of Sr (87.6g/mol) and Y (88.9g/mol), the lattice thermal conductivity (κL) of Sr1-xY xTiO3-δ is significantly reduced with increased Y-doping, owing to the smaller ionic radii of Y3+ (∼1.23Å, coordination number 12) compared to Sr2+ (∼1.44Å, coordination number 12) ions. In order to understand the thermal conductivity reduction mechanism, the κL in the Sr1-xY xTiO3-δ series are phenomenologically modeled with a modified Callaway's equation from 30-600K. Phonon scattering by elastic strain field due to ionic radii mismatch is found to be the prominent scattering mechanism in reducing κL of these materials. In addition, the effect of Y-doping on the elastic moduli of Sr1-xY xTiO3-δ (x=0, 0.1) is investigated using resonant ultrasound spectroscopy, which exhibits an anomaly in x=0.1 in the temperature range 300-600K. As a result, the phonon mean free path is found to be further reduced in the Sr0.9Y0.1TiO3-δ compared to that of SrTiO3-δ, resulting in a considerably low thermal conductivity κ∼2.7W/m-K at 760K. Finally, we report a thermoelectric figure of merit (ZT)∼0.3 at 760K in the Sr0.9Y 0.1TiO3-δ, the highest ZT value reported in the Y-doped SrTiO3 ceramics thus far. © 2014 AIP Publishing LLC.
Energy Technology Data Exchange (ETDEWEB)
Turner, Todd J.; Shade, Paul A.; Bernier, Joel V.; Li, Shiu Fai; Schuren, Jay C.; Lind, Jonathan; Lienert, Ulrich; Kenesei, Peter; Suter, Robert M.; Blank, Basil; Almer, Jonathan
2016-03-18
High-energy diffraction microscopy (HEDM) constitutes a suite of combined X-ray characterization methods, which hold the unique advantage of illuminating the microstructure and micromechanical state of a material during concurrent in situ mechanical deformation. The data generated from HEDM experiments provides a heretofore unrealized opportunity to validate meso-scale modeling techniques, such as crystal plasticity finite element modeling (CPFEM), by explicitly testing the accuracy of these models at the length scales where the models predict their response. Combining HEDM methods with in situ loading under known and controlled boundary conditions represents a significant challenge, inspiring the recent development of a new high-precision rotation and axial motion system for simultaneously rotating and axially loading a sample. In this paper, we describe the initial HEDM dataset collected using this hardware on an alpha-titanium alloy (Ti-7Al) under in situ tensile deformation at the Advanced Photon Source, Argonne National Laboratory. We present both near-field HEDM data that maps out the grain morphology and intragranular crystallographic orientations and far-field HEDM data that provides the grain centroid, grain average crystallographic orientation, and grain average elastic strain tensor for each grain. Finally, we provide a finite element mesh that can be utilized to simulate deformation in the volume of this Ti-7Al specimen. The dataset supporting this article is available in the National Institute of Standards and Technology (NIST) repository (http://hdl.handle.net/11256/599).
Elastic scattering of intermediate energy protons on 4He and 12C
International Nuclear Information System (INIS)
Khan, Z.A.
1981-01-01
The elastic angular distribution and polarization of approx. equal to 1 GeV protons on 4 He and 12 C have been analysed using the recently proposed correlation expansion for the Glauber amplitude by retaining terms up to three-body density only. The calculations include Coulomb and spin effects. Using realistic form factors for target nuclei it is found that we need to consider only up to the second-order density term to provide a satisfactory explanation of both kinds of experimental data in the available momentum transfer region. The contribution of the three-body density term is only marginal except in 4 He differential cross-section in the cm angular range 45 0 0 . (orig.)
Hinterberger, F; Altmeier, M; Bauer, F; Bisplinghoff, J; Büsser, K; Busch, M; Colberg, T; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jonas, E; Krause, H; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuk, T; Meinerzhagen, A; Naehle, O; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Trelle, H J; Weise, E; Wellinghausen, A; Woller, K; Ziegler, R
2000-01-01
The EDDA experiment at the cooler synchrotron COSY measures proton-proton elastic scattering excitation functions in the momentum range 0.8 - 3.4 GeV/c. In phase 1 of the experiment, spin-averaged differential cross sections were measured continuously during acceleration with an internal polypropylene (CH sub 2) fiber target, taking particular care to monitor luminosity as a function of beam momentum. In phase 2, excitation functions of the analyzing power A sub N and the polarization correlation parameters A sub N sub N , A sub S sub S and A sub S sub L are measured using a polarized proton beam and a polarized atomic hydrogen beam target. The paper presents recent d sigma/d OMEGA and A sub N data. The results provide excitation functions and angular distributions of high precision and internal consistency. No evidence for narrow structures was found. The data are compared to recent phase shift solutions.
Analyzing powers in π+p elastic scattering at intermediate energies
International Nuclear Information System (INIS)
Mokhtari, A.; Briscoe, W.J.; Eichon, A.D.
1985-01-01
The analyzing power, A/sub N/, has been measured for π + p elastic scattering at p/sub π/ = 471, 547, 625, and 687 MeV/c on a transversely polarized target. The results are compared with three recent partial-wave analyses for the isospin (3/2) channel. The agreement with our data for all three analyses is good at 471 MeV/c and reasonable at 547 and 625 MeV/c. At 687 MeV/c two of the analyses show a sharp maximum near costheta = -0.4 which is not seen in the data. There is no indication in our data of the existence of new, narrow Δ resonances
International Nuclear Information System (INIS)
Levits'kij, R.R.; Lyisnij, B.M.
2003-01-01
In order to study the dielectric, piezoelectric and elastic properties of ferroelectrics and antiferroelectrics of the KH 2 PO 4 family, we consider an extended proton tunneling model that takes into account the shear strain u 6 . In the four-particle cluster approximation for the short-range interactions and the mean field approximation for the long-range interaction we calculate the transverse components of the dielectric susceptibility tensor of the KH 2 PO 4 family ferroelectrics
Directory of Open Access Journals (Sweden)
O. A. Ponkratenko
2015-10-01
Full Text Available Diffraction range of available experimental differential cross sections of heavy ions on light nuclei elastic scattering for 17 pairs of the interacting nuclei with 4 ≤ А ≤ 20 have been analyzed in the projectile energy wide interval from 1 to 100 МеV/nucleon. Diffraction maxima and minima positions in the transferred momentum coordinates depending on projectile energy demonstrate smooth behavior at energies higher 2 - 4 МeV/nucleon, and practically do not depend on energy at energies up to 30 - 40 МеV/nucleon. These energy dependences of maxima (minima positions can be parameterized by simple functions. It was found the suitable approximations that describe reasonably the energy dependence of the maxima (minima positions of the experimental elastic scattering differential cross sections. These approximations were evaluated with the same parameters for all colliding nuclei groups.
International Nuclear Information System (INIS)
Ponkratenko, O.A.; Pyirnak, Val. M.; Rudchik, A.A.; Stepanenko, Yu.M.; Uleshchenko, V.V.; Shirma, Yu.O.
2015-01-01
Diffraction range of available experimental differential cross sections of heavy ions on light nuclei elastic scattering for the interactive nuclei 17 pairs with 4 ≤ A ≤ 20 have been analyzed in the projectile energy wide interval from 1 to 100 MeV/nucleon. Diffraction maxima and minima positions in the transferred momentum coordinates depending on projectile energy demonstrate smooth behavior at energies higher 2 - 4 MeV/nucleon and at energies to 30 - 40 MeV/nucleon - practically does not depend on energy. These energy dependences of maxima (minima) position. can be parameterized by simple functions. It was found the suitable approximations that describe reasonable the energy dependence of the maxima (minima) positions of the experimental elastic scattering differential cross sections. These approximations were evaluated with the same parameters for all colliding nuclei groups
Non-Conventional Thermodynamics and Models of Gradient Elasticity
Directory of Open Access Journals (Sweden)
Hans-Dieter Alber
2018-03-01
Full Text Available We consider material bodies exhibiting a response function for free energy, which depends on both the strain and its gradient. Toupin–Mindlin’s gradient elasticity is characterized by Cauchy stress tensors, which are given by space-like Euler–Lagrange derivative of the free energy with respect to the strain. The present paper aims at developing a first version of gradient elasticity of non-Toupin–Mindlin’s type, i.e., a theory employing Cauchy stress tensors, which are not necessarily expressed as Euler–Lagrange derivatives. This is accomplished in the framework of non-conventional thermodynamics. A one-dimensional boundary value problem is solved in detail in order to illustrate the differences of the present theory with Toupin–Mindlin’s gradient elasticity theory.
Elastic scattering and quasi-elastic transfers
International Nuclear Information System (INIS)
Mermaz, M.C.
1978-01-01
Experiments are presented which it will be possible to carry out at GANIL on the elastic scattering of heavy ions: diffraction phenomena if the absorption is great, refraction phenomena if absorption is low. The determination of the optical parameters can be performed. The study of the quasi-elastic transfer reactions will make it possible to know the dynamics of the nuclear reactions, form exotic nuclei and study their energy excitation spectrum, and analyse the scattering and reaction cross sections [fr
International Nuclear Information System (INIS)
Yang, D.S.; Nguyen Minh, D.; Chanchole, S.; Gharbi, H.; Valli, P.; Bornert, M.
2010-01-01
Document available in extended abstract form only. The construction of underground nuclear waste repositories will strongly disturb the initial thermo-hydro-chemo-mechanical equilibrium of the site. In addition to direct mechanical perturbations during excavation, which induce redistribution of the stresses and possible damage of the surrounding rock mass, the ventilation of the galleries will also modify the moisture content of the rock, resulting in shrinking or swelling, and more generally modifying the physical-chemical properties of the material. Safety concerns about preservation of confining properties of rock mass at short and long time scales require a deep understanding of the hydro-mechanical behavior of the host rock. In particular the dependence of elastic, possibly anisotropic, moduli and nonlinear properties (plasticity, damage, creep...) as a function of the moisture level, need to be quantified. In addition, in order to construct physically based micromechanical models of these dependencies, the various micro-mechanisms at their origin and their characteristic scales need to be identified. Various independent studies agree on the decrease of overall rigidity and failure stress of argillite with increasing humidity. A recent study making use of optical full-field strain measurement techniques on centi-metric samples under uniaxial compression suggests that this apparent decrease of elastic properties on wet samples can be essentially explained by the presence of a millimetric network of 'meso-cracks', induced by the preliminary unconfined hydration process. Indeed, thanks to the full-field measurement technique, it was possible to show that the mechanical response of undamaged areas, in-between cracks, was very similar at all moisture contents, both in terms of average strains and strain fluctuations at the micrometric scale of the composite structure of the rock (matrix clay + other mineral inclusions). The preliminary hydro
Study of the {sup 6}He+{sup 9}Be elastic scattering at low energies
Energy Technology Data Exchange (ETDEWEB)
Pires, K.C.C.; Lichtenthaeler, R.; Lepine-Szily, A.; Guimaraes, V.; Faria, P.N.; Crema, E.; Barioni, A.; Mendes Junior, V.; Morcelle, V.; Morais, M.C.; Pampa Condori, R.; Huiza, J.F.P. [Universidade de Sao Paulo (IF/USP), SP (Brazil). lnst. de Fisica. Dept. de Fisica Nuclear; Moro, A.M.; Rodriguez-Gallardo, M. [University of Seville (Sri Lanka). Dept. of Atomic, Molecular and Nuclear Physics; Assuncao, M. [Universidade Federal de Sao Paulo (UNIFESP), SP (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP) Sao Paulo, SP (Brazil); Mukherjee, S. [University of Baroda, Vadodara (India). Faculty of Science. Dept. of Physics
2011-07-01
New data of the {sup 6}He+{sup 9}Be elastic scattering at E{sub lab}=16.2MeV and 21.3MeV have been measured. A very large reaction cross section has been previously observed in the collision of {sup 6}He with medium and heavy mass targets, which has been attributed to high 6He breakup probability in the strong Coulomb + nuclear interaction. More recently the importance of neutron transfer reactions between projectile and target has been pointed out. The main goal of the present experiment is to investigate the halo nature of the {sup 6}He nucleus by its interaction with a light target. The experiment has been performed at the Pelletron Laboratory of the Institute of Physics of the University of Sao Paulo, Brazil, using the RIBRAS facility. The RIBRAS system consists of two superconducting solenoids used to focus and select the radioactive secondary beam. The {sup 6}He secondary beam was produced by the {sup 9}Be({sup 7}Li,{sup 6}He) reaction with a {sup 7}Li primary beam of 200nA. The detection system consisted of four {Delta}E-E Silicon telescopes, with 20{mu}m and 1000{mu}m thickness respectively, which allow to separate the {sup 6}He particles from the {sup 7}Li, {sup 4}He, and light particles contaminants. The {sup 6}He+{sup 9}Be angular distributions have been analyzed with optical model, Coupled Channels (CC) and Continuum Discretized Coupled Channels (CDCC) calculations. The comparison between the experimental data and the CDCC calculations allow us to conclude that the breakup of the projectile via the coupling to the {sup 6}He 2{sup +} resonance is very important to reproduce the data. In addition, we studied the effect of excitation of the {sup 9}Be target explicitly by a CC calculation, using a collective model to describe the excitation of the first low lying states of {sup 9}Be. We found that the coupling to these states significantly affects the elastic scattering. From this analysis it was possible to obtain the total reaction cross section which was
Energy absorption at high strain rate of glass fiber reinforced mortars
Directory of Open Access Journals (Sweden)
Fenu Luigi
2015-01-01
Full Text Available In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF was finally evaluated.
Neutron Elastic Scattering Cross Sections of Iron and Zinc in the Energy Region 2.5 to 8.1 MeV
International Nuclear Information System (INIS)
Holmqvist, B.; Johansson, S.G.; Lodin, G.; Wiedling, T.; Kiss, A.
1966-12-01
Angular distributions were measured for the elastic scattering of neutrons from iron at five energies between 3.0 and 8. 1 MeV and from zinc at eight energies between 2.5 and 8.1 MeV. Time-of-flight technique was used. Corrections for neutron flux attenuation, multiple elastic scattering, and the finite geometry of the source-sample detector system were made by using a Monte Carlo program. An optical model potential with Saxon-Woods form factors was used to fit theoretical angular distributions to the experimental ones. The parameter values giving the best fits to the experimental distributions were calculated by a computer
Energy Technology Data Exchange (ETDEWEB)
Saleem, M.; Fazal-e-Aleem; Rifique, M.
1987-03-01
The recent experimental measurements for anti-pp and ..cap alpha cap alpha.. elastic scattering at high energies have shown that the Chou-Yang conjecture regarding the relationship between the electromagnetic and the hadronic form factor of a particle is only an approximation. A new ansatz has been proposed to obtain hadronic form factors of proton and the ..cap alpha..-particle. These form factors have been used to explain the various characteristics of anti-pp, ..cap alpha cap alpha.. and p..cap alpha.. elastic scattering at high energies.
Neutron Elastic Scattering Cross Sections of Iron and Zinc in the Energy Region 2.5 to 8.1 MeV
Energy Technology Data Exchange (ETDEWEB)
Holmqvist, B; Johansson, S G; Lodin, G; Wiedling, T [AB Atomenergi, Nyko eping (Sweden); Kiss, A [Inst. for Experimental Physics, Univ. of Debrecen, De brecen (Hungary)
1966-12-15
Angular distributions were measured for the elastic scattering of neutrons from iron at five energies between 3.0 and 8. 1 MeV and from zinc at eight energies between 2.5 and 8.1 MeV. Time-of-flight technique was used. Corrections for neutron flux attenuation, multiple elastic scattering, and the finite geometry of the source-sample detector system were made by using a Monte Carlo program. An optical model potential with Saxon-Woods form factors was used to fit theoretical angular distributions to the experimental ones. The parameter values giving the best fits to the experimental distributions were calculated by a computer.
Data-Driven Problems in Elasticity
Conti, S.; Müller, S.; Ortiz, M.
2018-01-01
We consider a new class of problems in elasticity, referred to as Data-Driven problems, defined on the space of strain-stress field pairs, or phase space. The problem consists of minimizing the distance between a given material data set and the subspace of compatible strain fields and stress fields in equilibrium. We find that the classical solutions are recovered in the case of linear elasticity. We identify conditions for convergence of Data-Driven solutions corresponding to sequences of approximating material data sets. Specialization to constant material data set sequences in turn establishes an appropriate notion of relaxation. We find that relaxation within this Data-Driven framework is fundamentally different from the classical relaxation of energy functions. For instance, we show that in the Data-Driven framework the relaxation of a bistable material leads to material data sets that are not graphs.
Polarization of recoil deuteron in ed elastic scattering at medium energies
International Nuclear Information System (INIS)
Bhalerao, R. S.
1981-12-01
Vector and tensor polarizations of the recoil deuteron in ed elastic scattering are calculated for THETA=0deg-180deg and q 2 2 . A longitudinally polarized electron beam is assumed to scatter off an unpolarized deuteron target. Calculations are made in the relativistic impulse approximation using a recently described approach based on the Bethe-Salpeter equation. Results are different, at high q 2 even qualitatively so, from those of a non-relativistic calculation, and a relativistic calculation which takes the spectator nucleon on-mass-shell. In the light of these results a recent suggestion that the polarization measurements would throw new light on the off-shell behavior and tensor force strength of the NN interaction are reexamined. Results are also presented for the three deuteron form factors Gsub(C), Gsub(Q), and Gsub(M), and the often-needed related quantities Ssub(S), Ssub(Q), and Ssub(M). The latter results may have an important implication in high-momentum transfer reactions involving deuteron. (author)
International Nuclear Information System (INIS)
Gajo, A.
2011-01-01
A general approach is proposed for defining the macroscopic free energy density function (and its complement, the free enthalpy) of a saturated porous medium submitted to finite deformations under non-isothermal conditions, in the case of compressible fluid and solid constituents. Reference is made to an elementary volume treated as an 'open system', moving with the solid skeleton. The proposed free energy depends on the generalised strains (namely an appropriate measure of the strain of the solid skeleton and the variation in fluid mass content) and the absolute temperatures of the solid and fluid phases (which are assumed to differ from each other for the sake of generality). This macroscopic energy proves to be a potential for the generalised stresses (namely the associated measure of the total stress and the free enthalpy of the pore fluid per unit mass) and the entropies of the solid and fluid phases. In contrast with mixture theories, the resulting free energy is not the simple sum of the free energies of the single constituents. Two simplified cases are examined in detail, i.e. the semi-linear theory (originally proposed for isothermal conditions and extended here to non-isothermal problems) and the linear theory. The proposed approach paves the way to the consistent non-isothermal-hyper-elastic-plastic modelling of saturated porous media with a compressible fluid and solid constituents. (authors)
Implementation of a demand elasticity model in the building energy management system
Ożadowicz, A.; Grela, J.; Babar, M.
2016-01-01
Nowadays, crucial part of modern Building Automation and Control Systems (BACS) is electric energy management. An active demand side management is very important feature of a Building Energy Management Systems (BEMS) integrated within the BACS. Since demand value changes in time and depends on
Erler, Norbert; Groß, Michael
2015-05-01
Since many years the relevance of fibre-reinforced polymers is steadily increasing in fields of engineering, especially in aircraft and automotive industry. Due to the high strength in fibre direction, but the possibility of lightweight construction, these composites replace more and more traditional materials as metals. Fibre-reinforced polymers are often manufactured from glass or carbon fibres as attachment parts or from steel or nylon cord as force transmission parts. Attachment parts are mostly subjected to small strains, but force transmission parts usually suffer large deformations in at least one direction. Here, a geometrically nonlinear formulation is necessary. Typical examples are helicopter rotor blades, where the fibres have the function to stabilize the structure in order to counteract large centrifugal forces. For long-run analyses of rotor blade deformations, we have to apply numerically stable time integrators for anisotropic materials. This paper presents higher-order accurate and numerically stable time stepping schemes for nonlinear elastic fibre-reinforced continua with anisotropic stress behaviour.
Grain-boundary free energy in an assembly of elastic disks.
Lusk, Mark T; Beale, Paul D
2004-02-01
Grain-boundary free energy is estimated as a function of misoriention for symmetric tilt boundaries in an assembly of nearly hard disks. Fluctuating cell theory is used to accomplish this since the most common techniques for calculating interfacial free energy cannot be applied to such assemblies. The results are analogous to those obtained using a Leonard-Jones potential, but in this case the interfacial energy is dominated by an entropic contribution. Disk assemblies colorized with free and specific volume elucidate differences between these two characteristics of boundary structure. Profiles are also provided of the Helmholtz and Gibbs free energies as a function of distance from the grain boundaries. Low angle grain boundaries are shown to follow the classical relationship between dislocation orientation/spacing and misorientation angle.
Bekhet, Hussain Ali; Harun, Nor Hamisham
2017-01-01
Renewable energy is a significant issue in attaining low-carbon emissions for Malaysia’s economic development path. Therefore, this study investigates the determinants (capital, labour, economic growth, and financial development), which has an influence on renewable energy generation, using time-series data from 1982 to 2015 period. The augmented Cobb–Douglas production function, F-bound test, and vector error correction model are employed to achieve the objectives of the study. The result of...
International Nuclear Information System (INIS)
Pillai, C.; Barlow, D.B.; Berman, B.L.; Briscoe, W.J.; Mokhtari, A.; Nefkens, B.M.K.; Sadler, M.E.
1991-01-01
Data are presented on the energy and angle dependence of the charge-symmetry superratio R and simple ratios r 1 ' and r 2 ' for π ± elastic scattering from 3 H and 3 He. r 1 ' and r 2 ' were normalized with respect to π + d and π - d elastic scattering, which is assumed to have the ratio 1.0. The beam energies are T π =142, 180, and 220 MeV, and the scattering angle, θ L , ranges from 40 degree to 110 degree. In all cases measured it is found that R>1, r 1 ' congruent 1, and r 2 ' >1. These results provide substantial evidence for charge-symmetry violation. The angular distributions for π ± H and π ± 3 He elastic scattering also have been measured and comparisons are made with various model calculations
International Nuclear Information System (INIS)
Guiasu, I.
1978-01-01
The elastic γ-nucleon scattering represents an indirect powerful method for the nucleon structure investigation. Some theoretical aspects of this problem are treated in the presented thesis. After a general introduction into the subject and a short review of the up-to-date literature, the first chapter contains kinematics and dynamical preliminaries of reaction γ+N→γ+N. In chapter II, the low energy theorems are discussed and extended up to six power in the photon laboratory energies, ω; the six structure dependent constants which appear in the differential cross section in this order are defined and computed, and an extraction for the proton electromagnetic polarizabilities α,β from the experimental data is performed. A new dispersive analysis of the γ+N→γ+N process at photon laboratory energies lower than 450 Mev is introduced and used for numerical calculation in chapter III; some improvements are obtained in the comparison with the experimental data, with respect to other previous calculations. In the last chapter, two different sum rules for the difference (α-β) are established and numerically computed - these theoretical predictions agree with the values extracted from experience; based on the analyticity properties of the invariant amplitudes, an inequality is written down connecting an integral over the differential cross section of the process and the static properties of the nucleon (mass, charge, anomalous magnetic moment). (author)
Controlling the exciton energy of a nanowire quantum dot by strain fields
Energy Technology Data Exchange (ETDEWEB)
Chen, Yan; Zhang, Jiaxiang; Ding, Fei, E-mail: f.ding@ifw-dresden.de [Institute for Integrative Nanosciences, IFW Dresden, Helmholtz Strasse 20, 01069 Dresden (Germany); Zadeh, Iman Esmaeil; Jöns, Klaus D.; Fognini, Andreas; Zwiller, Val [Kavli Institute of Nanoscience, Delft University of Technology, 2600 GA Delft (Netherlands); Reimer, Michael E. [Institute for Quantum Computing and Department of Electrical and Computer Engineering, University of Waterloo, Waterloo, N2L 3G1 (Canada); Dalacu, Dan; Poole, Philip J. [National Research Council, Ottawa, Ontario K1A 0R6 (Canada); Schmidt, Oliver G. [Institute for Integrative Nanosciences, IFW Dresden, Helmholtz Strasse 20, 01069 Dresden (Germany); Material Systems for Nanoelectronics, Chemnitz University of Technology, Reichenhainer Strasse 70, 09107 Chemnitz (Germany)
2016-05-02
We present an experimental route to engineer the exciton energies of single quantum dots in nanowires. By integrating the nanowires onto a piezoelectric crystal, we controllably apply strain fields to the nanowire quantum dots. Consequently, the exciton energy of a single quantum dot in the nanowire is shifted by several meVs without degrading its optical intensity and single-photon purity. Second-order autocorrelation measurements are performed at different strain fields on the same nanowire quantum dot. The suppressed multi-photon events at zero time delay clearly verify that the quantum nature of single-photon emission is well preserved under external strain fields. The work presented here could facilitate on-chip optical quantum information processing with the nanowire based single photon emitters.
Influence of ceramic dental crown coating substrate thickness ratio on strain energy release rate
Khasnulhadi, K.; Daud, R.; Mat, F.; Noor, S. N. F. M.; Basaruddin, K. S.; Sulaiman, M. H.
2017-10-01
This paper presents the analysis of coating substrate thickness ratio effect on the crown coating fracture behaviour. The bi-layer material is examined under four point bending with pre-crack at the bottom of the core material by using finite element. Three different coating thickness of core/substrate was tested which is 1:1, 1:2 and 2:1. The fracture parameters are analysed based on bilayer and homogenous elastic interaction. The result shows that the ratio thickness of core/veneer provided a significant effect on energy release rate.
Elastic properties of Gum Metal
International Nuclear Information System (INIS)
Kuramoto, Shigeru; Furuta, Tadahiko; Hwang, Junghwan; Nishino, Kazuaki; Saito, Takashi
2006-01-01
In situ X-ray diffraction measurements under tensile loading and dynamic mechanical analysis were performed to investigate the mechanisms of elastic deformation in Gum Metal. Tensile stress-strain curves for Gum Metal indicate that cold working substantially decreases the elastic modulus while increasing the yield strength, thereby confirming nonlinearity in the elastic range. The gradient of each curve decreased continuously to about one-third its original value near the elastic limit. As a result of this decrease in elastic modulus and nonlinearity, elastic deformability reaches 2.5% after cold working. Superelasticity is attributed to stress-induced martensitic transformations, although the large elastic deformation in Gum Metal is not accompanied by a phase transformation
Robust piezoelectric composites for energy harvesting in high-strain environments
Ende, D.A. van der; Groen, W.A.; Zwaag, S. van der
2013-01-01
High-strain environments, such as are found in automobile tires, provide deformation energy that can be harvested using piezoelectric materials, for instance, for powering electronics such as wireless sensors. Despite numerous efforts, none of the present devices easily satisfy the stringent
Baziar, Mohammad H.; Jafarian, Yaser; Shahnazari, Habib; Movahed, Vahid; Amin Tutunchian, Mohammad
2011-11-01
Liquefaction is a catastrophic type of ground failure, which usually occurs in loose saturated soil deposits under earthquake excitations. A new predictive model is presented in this study to estimate the amount of strain energy density, which is required for the liquefaction triggering of sand-silt mixtures. A wide-ranging database containing the results of cyclic tests on sand-silt mixtures was first gathered from previously published studies. Input variables of the model were chosen from the available understandings evolved from the previous studies on the strain energy-based liquefaction potential assessment. In order to avoid overtraining, two sets of validation data were employed and a particular monitoring was made on the behavior of the evolved models. Results of a comprehensive parametric study on the proposed model are in accord with the previously published experimental observations. Accordingly, the amount of strain energy required for liquefaction onset increases with increase in initial effective overburden pressure, relative density, and mean grain size. The effect of nonplastic fines on strain energy-based liquefaction resistance shows a more complicated behavior. Accordingly, liquefaction resistance increases with increase in fines up to about 10-15% and then starts to decline for a higher increase in fines content. Further verifications of the model were carried out using the valuable results of some downhole array data as well as centrifuge model tests. These verifications confirm that the proposed model, which was derived from laboratory data, can be successfully utilized under field conditions.
Loendersloot, Richard; Ooijevaar, T.H.; Warnet, Laurent; Akkerman, Remko; de Boer, Andries; Meguid, S.A.; Gomes, J.F.S.
2009-01-01
The feasibility of a vibration based damage identification method is investigated. The Modal Strain Energy method is applied to a T–beam structure. The dynamic response of an intact structure and a damaged, delaminated structure is analysed employing a commercially available Finite Element package.
Regional Differences in the Price-Elasticity of Demand for Energy
Energy Technology Data Exchange (ETDEWEB)
Bernstein, M. A.; Griffin, J.
2006-02-01
At the request of the National Renewable Energy Laboratory (NREL), the RAND Corporation examined the relationship between energy demand and energy prices with the focus on whether the relationships between demand and price differ if these are examined at different levels of data resolution. In this case, RAND compares national, regional, state, and electric utility levels of data resolution. This study is intended as a first step in helping NREL understand the impact that spatial disaggregation of data can have on estimating the impacts of their programs. This report should be useful to analysts in NREL and other national laboratories, as well as to policy nationals at the national level. It may help them understand the complex relationships between demand and price and how these might vary across different locations in the United States.
Deflection of high energy channeled charged particles by elastically bent silicon single crystals
International Nuclear Information System (INIS)
Gibson, W.M.; Kim, I.J.; Pisharodoy, M.; Salman, S.M.; Sun, C.R.; Wang, G.H.; Wijayawardana, R.; Forster, J.S.; Mitchell, I.V.; Baker, S.I.; Carrigan, R.A. Jr.; Toohig, T.E.; Avdeichikov, V.V.; Ellison, J.A.; Siffert, P.
1984-01-01
An experiment has been carried out to observe the deflection of charged particles by planar channeling in bent single crystals of silicon for protons with energy up to 180 GeV. Anomolous loss of particles from the center point of a three point bending apparatus was observed at high incident particle energy. This effect has been exploited to fashion a 'dechanneling spectrometer' to study dechanneling effects due to centripital displacement of channeled particle trajectories in a bent crystal. The bending losses generally conform to the predictions of calculations based on a classical model. (orig.)
DEFF Research Database (Denmark)
Dyre, Jeppe; Olsen, Niels Boye; Christensen, Tage Emil
1996-01-01
A model for the viscosity of glass-forming molecular liquids is proposed in which a "flow event" requires a local volume increase. The activation energy for a flow event is identified with the work done in shoving aside the surrounding liquid; this work is proportional to the high-frequency shear...
Energy Technology Data Exchange (ETDEWEB)
Holmqvist, B; Johansson, S G; Lodin, G; Wiedling, T [AB Atomenergi, Nyko eping (Sweden); Salama, M [Reactor and Neutron Physics Dept., Atomic Energy Es tablishment, Cairo (Egypt)
1970-07-01
Elastic neutron scattering measurements have been performed on the natural elements chromium, iron and nickel. Angular distributions were recorded in the interval 20 to 160 deg at several energies in the region 1.77 to 2.76 MeV. The experimental data were analysed in terms of the optical model, applying a spherical nuclear potential.
Negative stiffness honeycombs as tunable elastic metamaterials
Goldsberry, Benjamin M.; Haberman, Michael R.
2018-03-01
Acoustic and elastic metamaterials are media with a subwavelength structure that behave as effective materials displaying atypical effective dynamic properties. These material systems are of interest because the design of their sub-wavelength structure allows for direct control of macroscopic wave dispersion. One major design limitation of most metamaterial structures is that the dynamic response cannot be altered once the microstructure is manufactured. However, the ability to modify wave propagation in the metamaterial with an external stimulus is highly desirable for numerous applications and therefore remains a significant challenge in elastic metamaterials research. In this work, a honeycomb structure composed of a doubly periodic array of curved beams, known as a negative stiffness honeycomb (NSH), is analyzed as a tunable elastic metamaterial. The nonlinear static elastic response that results from large deformations of the NSH unit cell leads to a large variation in linear elastic wave dispersion associated with infinitesimal motion superposed on the externally imposed pre-strain. A finite element model is utilized to model the static deformation and subsequent linear wave motion at the pre-strained state. Analysis of the slowness surface and group velocity demonstrates that the NSH exhibits significant tunability and a high degree of anisotropy which can be used to guide wave energy depending on static pre-strain levels. In addition, it is shown that partial band gaps exist where only longitudinal waves propagate. The NSH therefore behaves as a meta-fluid, or pentamode metamaterial, which may be of use for applications of transformation elastodynamics such as cloaking and gradient index lens devices.
International Nuclear Information System (INIS)
Hostachy, J.Y.
1987-01-01
The elastic and inelastic scattering angular distributions of 12 C on the targets 12 C and 208 Pb have been measured at the Laboratoire National Saturne (Saclay) using the spectrometer SPES 1. The data have been analysed in the framework of the optical model with Woods-Saxon potentials. A near side/far side decomposition of the cross-section has provided a more detailed insight into the refraction effects. These analysises show that the strong absorption radius, the reaction cross-section, and consequently the absorption in the surface region, decrease when the incident energy increases, allowing to probe the inner part of the ion-ion potential. The transparency region extends down to a radial internuclei distance of about 3 fm for the 12 C - 12 C system and 8 fm for the 12 C - 208 Pb system. The onset of a decrease of the imaginary potential has been deduced for the two systems. The real potential is also decreasing, but much more rapidly for the 12 C - 208 Pb system than for 12 C- 12 C. We have also developed a microscopic approach in the optical limit of the Glauber theory, including the Pauli-blocking, the Fermi motion and the nucleus finite size effects. For the intermediate energies, the calculations are in fair agreement with the experimental data [fr
International Nuclear Information System (INIS)
Miyashiro, S.; Fujita, S.; Okita, T.; Okuda, H.
2012-01-01
Highlights: ► Strain effects on defect formation were evaluated at various PKA energies by MD. ► Radiation-induced defects were increased numerically by external strain. ► Enhanced formation of larger clusters causes the numerical increase of defects. ► Strain influence on the number of defects was greatest at about 20 keV PKA. ► Cluster size, which is mostly affected by strain, was greater with higher PKA energy. - Abstract: Molecular Dynamics (MD) simulations were conducted to investigate the influence of applied tensile strain on defect production during cascade damages at various Primary Knock-on Atom (PKA) energies of 1–30 keV. When 1% strain was applied, the number of surviving defects increased at PKA energies higher than 5 keV, although they did not increase at 1 keV. The rate of increase by strain application was higher with higher PKA energy, and attained the maximum at 20 keV PKA energy with a subsequent gradual decrease at 30 keV PKA energy The cluster size, mostly affected by strain, was larger with higher PKA energy, although clusters with fewer than seven interstitials did not increase in number at any PKA energy.
Regge pole plus cut model for proton-antiproton elastic scattering at collider and tevatron energies
International Nuclear Information System (INIS)
Aleem, Fazal; Saleem, Mohammad
1988-01-01
The Regge pole plus cut model has been used to explain the data at the collider energies √=546 and 630 GeV and the most recent differential cross-section results at √=1.8 TeV. Predictions of the model at 1.8 and 40 TeV are compared with those of Bourrely et al. (1984). (author). 22 refs., 7 figs
Direct strain energy harvesting in automobile tires using piezoelectric PZT–polymer composites
International Nuclear Information System (INIS)
Van den Ende, D A; Van de Wiel, H J; Groen, W A; Van der Zwaag, S
2012-01-01
Direct piezoelectric strain energy harvesting can be used to power wireless autonomous sensors in environments where low frequency, high strains are present, such as in automobile tires during operation. However, these high strains place stringent demands on the materials with respect to mechanical failure or depolarization, especially at elevated temperatures. In this work, three kinds of ceramic–polymer composite piezoelectric materials were evaluated and compared against state-of-the-art piezoelectric materials. The new composites are unstructured and structured composites containing granular lead zirconate titanate (PZT) particles or PZT fibers in a polyurethane matrix. The composites were used to build energy harvesting patches which were attached to a tire and tested under simulated rolling conditions. The energy density of the piezoelectric ceramic–polymer composite materials is initially not as high as that of the reference materials (a macro-fiber composite and a polyvinylidene fluoride polymer). However, the area normalized power output of the composites after temperature and strain cycling is comparable to that of the reference devices because the piezoelectric ceramic–polymer composites did not degrade during operation. (paper)
Sellers, Benjamin D; James, Natalie C; Gobbi, Alberto
2017-06-26
Reducing internal strain energy in small molecules is critical for designing potent drugs. Quantum mechanical (QM) and molecular mechanical (MM) methods are often used to estimate these energies. In an effort to determine which methods offer an optimal balance in accuracy and performance, we have carried out torsion scan analyses on 62 fragments. We compared nine QM and four MM methods to reference energies calculated at a higher level of theory: CCSD(T)/CBS single point energies (coupled cluster with single, double, and perturbative triple excitations at the complete basis set limit) calculated on optimized geometries using MP2/6-311+G**. The results show that both the more recent MP2.X perturbation method as well as MP2/CBS perform quite well. In addition, combining a Hartree-Fock geometry optimization with a MP2/CBS single point energy calculation offers a fast and accurate compromise when dispersion is not a key energy component. Among MM methods, the OPLS3 force field accurately reproduces CCSD(T)/CBS torsion energies on more test cases than the MMFF94s or Amber12:EHT force fields, which struggle with aryl-amide and aryl-aryl torsions. Using experimental conformations from the Cambridge Structural Database, we highlight three example structures for which OPLS3 significantly overestimates the strain. The energies and conformations presented should enable scientists to estimate the expected error for the methods described and we hope will spur further research into QM and MM methods.
International Nuclear Information System (INIS)
Murray, Gabriel; Gandhi, Farhan
2010-01-01
Morphing aerospace structures could benefit from the ability of structural elements to transition from a stiff load-bearing state to a relatively compliant state that can undergo large deformation at low actuation cost. The present paper focuses on multi-layered beams with controllable flexural stiffness—comprising polymer layers affixed to the surfaces of a base beam and cover layers, in turn, affixed to the surfaces of the polymer layers. Heating the polymer through the glass transition reduces its shear modulus, decouples the cover layers from the base beam and reduces the overall flexural stiffness. Although the stiffness and actuation force required to bend the beam reduce, the energy required to heat the polymer layer must also be considered. Results show that for beams with low slenderness ratios, relatively thick polymer layers, and cover layers whose extensional stiffness is high, the decoupling of the cover layers through softening of the polymer layers can result in flexural stiffness reductions of over 95%. The energy savings are also highest for these configurations, and will increase as the deformation of the beam increases. The decoupling of the cover layers from the base beam through the softening of the polymer reduces the axial strains in the cover layers significantly; otherwise material failure would prevent large deformation. Results show that when the polymer layer is stiff, the cover layers are the dominant contributors to the total energy in the beam, and the energy in the polymer layers is predominantly axial strain energy. When the polymer layers are softened the energy in the cover layers is a small contributor to the total energy which is dominated by energy in the base beam and shear strain energy in the polymer layer
Twisting failure of centrally loaded open-section columns in the elastic range
Kappus, Robert
1938-01-01
In the following report a complete theory of twisting failure by the energy method is developed, based on substantially the same assumptions as those employed by Wagner and Bleich. Problems treated in detail are: the stress and strain condition under St. Venant twist and in twist with axial constraint; the concept of shear center and the energy method for problems of elastic stability.
DEFF Research Database (Denmark)
Langbein, Wolfgang Werner; Hvam, Jørn Märcher
2002-01-01
The directional dynamics of the resonant Rayleigh scattering from a semiconductor microcavity is investigated. When optically exciting the lower polariton branch, the strong dispersion results in a directional emission on a ring. The coherent emission ring shows a reduction of its angular width...... for increasing time after excitation, giving direct evidence for the time-energy uncertainty in the dynamics of the scattering by disorder. The ring width converges with time to a finite value, a direct measure of an intrinsic momentum broadening of the polariton states localized by multiple disorder scattering....
Do we understand near-forward elastic scattering up to TeV energies?
Bourrely, Claude; Wu, Tai Tsun
2015-01-01
In 1970, on purely theoretical grounds, all total hadronic total cross sections were predicted to increase without limit for higher and higher energies. This was contrary to the conventional belief at that time. In 1978, an accurate phenomeno- logical model was formulated for the case of proton-proton and antiproton-proton interactions. The parameters for this model were slightly improved in 1984 using the additional available experimental data. Since then, for thirty years these param- eters have not changed. This development, including especially the difficult task of formulating this phenomenological model and the comparison of the predictions of this model with later experimental results, is summarized.
Microscopic study of elastic and inelastic ALPHA-nucleus scattering at medium energies
International Nuclear Information System (INIS)
Dao Tien Khoa; Hoang Si Than; Do Cong Cuong; Ngo Van Luyen; Nguyen Ngoc Quynh; Nguyen Tuan Anh
2007-01-01
Analyses of the inelastic α + 12 C scattering at medium energies have indicated that the strength of the Hoyle state (the isoscalar O 2 + excitation at 7.65 MeV in 12 C) seems to exhaust only 7 to 9% of the monopole energy weighted sum rule (EWSR), compared to about 15% of the EWSR extracted from inelastic electron scattering data. The full monopole transition strength predicted by realistic microscopic α-cluster models of the Hoyle state can be shown to exhaust up to 22% of the EWSR. To explore the missing monopole strength in the inelastic α + 12 C scattering, we have performed a fully microscopic folding model analysis of the inelastic α + 12 C scattering at E lab =104 to 240 MeV using the 3-α resonating group wave function of the Hoyle state obtained by Kamimura, and a complex density-dependent M3Y interaction newly parametrized based on the Brueckner Hartree Fock results for nuclear matter. Our folding model analysis has shown consistently that the missing monopole strength of the Hoyle state is not associated with the uncertainties in the analysis of the α + 12 C scattering, but is most likely due to the short lifetime and weakly bound structure of this state which significantly enhances absorption in the exit α + 12 C * (O 2 + ) channel. (author)
International Nuclear Information System (INIS)
Baktibayev, M.K.; Burminskii, V.P.; Burtebaev, N.; Dzazairov -Kakhramanov, V.; Hassan, S.F.; Satpaev, N.K.; Zazulin, D.M.
2004-01-01
Full text: The fulfillment of planned works on measurements of differential cross sections of elastic scattering of protons on nuclear 12 C at the energy region of 350†1050 keV suggests the preparation of thin self - supporting carbon target. The self - supporting target is necessary in order to perform investigations in the total angular range. In the future last data will be used in order to determine optical potentials and scattering phases for this nuclear in the energy range of astrophysical interest. There was prepared target layer of the 12 C with natural composition of carbon and of thickness of 17.4 μg/cm 2 . The spraying was conducted in the vacuum evaporation installation (VUP - 4) by an electron bombardment method. Carbon was sprayed on a glass plate with previously deposited of layer salt. After a heating during 12 hours at the temperature of 150 o C the film of carbon was floated from glass plate and self - supporting target has been picked up on the specially prepared target frame. In order to determine thickness of target there was used the resonance chamber, installed in the protons channel of the accelerator RAC - 2 - 1 (INP NNC RK), with the help of which there was measured energy loss of the protons beam during the passage through target, disposed in the central chamber. For this purpose there was used the reaction 27 Al(p,γ) 28 Si with narrow resonance with E R = 992 keV and with detection of gamma-quanta with E γ = 1779 keV. On shift of the resonance E R =992 keV in the reaction 27 Al(p,γ) 28 Si, which takes place owing to protons energy loss in the thickness of carbon film, and using table values of brake quantities S(E p )[MeV·cm 2 /g] [1], there was determined thickness of this fine film. Such the method allows to determine thicknesses of films in the interval of (10 † 100) mcg/cm 2 with the accuracy of not worse than 5%. In the present work there were carried out measurements of angular distributions of cross sections of the
International Nuclear Information System (INIS)
Phan, Thien Q.; Levine, Lyle E.; Lee, I-Fang; Xu, Ruqing; Tischler, Jonathan Z.; Huang, Yi; Langdon, Terence G.; Kassner, Michael E.
2016-01-01
Synchrotron X-ray microbeam diffraction was used to measure the full elastic long range internal strain and stress tensors of low dislocation density regions within the submicrometer grain/subgrain structure of equal-channel angular pressed (ECAP) aluminum alloy AA1050 after 1, 2, and 8 passes using route B C . This is the first time that full tensors were measured in plastically deformed metals at this length scale. The maximum (most tensile or least compressive) principal elastic strain directions for the unloaded 1 pass sample for the grain/subgrain interiors align well with the pressing direction, and are more random for the 2 and 8 pass samples. The measurements reported here indicate that the local stresses and strains become increasingly isotropic (homogenized) with increasing ECAP passes using route B C . The average maximum (in magnitude) LRISs are −0.43 σ a for 1 pass, −0.44 σ a for 2 pass, and 0.14 σ a for the 8 pass sample. These LRISs are larger than those reported previously because those earlier measurements were unable to measure the full stress tensor. Significantly, the measured stresses are inconsistent with the two-component composite model.
International Nuclear Information System (INIS)
Ho, T.; Rabitz, H.
1989-01-01
Elastic differential cross sections in atomic crossed beam experiments contain detailed information about the underlying interatomic potentials. The functional sensitivity density of the cross sections with respect to the potential δσ(θ)/δV(R) reveals such information and has been implemented in an iterative inversion procedure, analogous to that of the Newton--Raphson technique. The stability of the inversion is achieved with the use of the regularization method of Tikhonov and Miller. It is shown that given a set of well resolved and noise-free differential cross section data within a limited angular range and given a reasonable starting reference potential, the recovered potential accurately resembles the desired one in the important region, i.e., the region to which the scattering data are sensitive. The region of importance depends upon the collision energy relative to the well depth of the potential under study; usually a higher collision energy penetrates deeper into the repulsive part of the potential and thus accordingly yields a more accurate potential in that part. The inversion procedure produces also a quality function indicating the well determined radial region. Moreover, the extracted potential is quite independent of the functional form of the reference potential in contrast to curve fitting approaches. As illustrations, the model inert gas systems He--Ne and Ne--Ar have been considered. For collision energies within an order of magnitude of the associated potential well depth, the attractive part of the potential can be determined to high precision provided that scattering data at small enough angles are available
The role of non-elastic nuclear processes for intermediate-energy protons in silicon targets
Energy Technology Data Exchange (ETDEWEB)
Hormaza, Joel Mesa, E-mail: jmesa@ibb.unesp.br [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil); Garcia, Cesar E., E-mail: cgarcia@instec.cu [Instituto Superior de Tecnologias y Ciencias Aplicadas (InSTEC), Havana (Cuba); Arruda Neto, Joao D.T.; Rodrigues, Tulio E., E-mail: arruda@if.usp.br, E-mail: tulio@if.usp.br [Universidade de Sao Paulo (USP), Sao Paulo, SP (Brazil). Instituto de Fisica; Schelin, Hugo R.; Denyak, Valery, E-mail: schelin@utfpr.edu.br, E-mail: denyak@gmail.com [Instituto de Pesquisa Pele Pequeno Principe, Curitiba, PR (Brazil); Paschuck, Sergei A.; Evseev, Ivan, E-mail: sergei@utfpr.edu.br, E-mail: evseev@utfpr.edu.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)
2013-07-01
The transportation of energetic ions in bulk matter is of direct interest in several areas including shielding against ions originating from either space radiations or terrestrial accelerators, cosmic ray propagation studies in galactic medium, or radiobiological effects resulting from the work place or clinical exposures. For carcinogenesis, terrestrial radiation therapy, and radiobiological research, knowledge of beam composition and interactions is necessary to properly evaluate the effects on human and animal tissues. For the proper assessment of radiation exposures both reliable transport codes and accurate input parameters are needed. In the last years efforts have been increasing in order to develop more effective models to describe and predict the damages induced by radiation in electronic devices. In this sense, the interaction of protons with those devices, particularly which operate in space, is a topic of paramount importance, mainly because although the majority of them are made with silicon, experimental data on p+Si nuclear processes is very sparse. In this work we have used a new quite sophisticated Monte Carlo multicollisional intranuclear cascade (MCMC) code for pre-equilibrium emission, plus de-excitation of residual nucleus by two ways: evaporation of particles (mainly nucleons, but also composites) and possibly fragmentation/fission in the case of heavy residues, in order to study some observable of nuclear interaction of protons between 100-200 MeV in a {sup 28}Si target. The code has been developed with very recent improvements that take into account Pauli blocking effects in a novel and more precise way, as well as a more rigorous energy balance, an energy stopping time criterion for pre-equilibrium emission and the inclusion of deuteron, triton and 3He emissions in the evaporation step, which eventually concurs with fragmentation/break-up stage. The fragment mass distributions, as well as the multiplicities and the spectra of secondary
The role of non-elastic nuclear processes for intermediate-energy protons in silicon targets
International Nuclear Information System (INIS)
Hormaza, Joel Mesa; Garcia, Cesar E.; Arruda Neto, Joao D.T.; Rodrigues, Tulio E.; Paschuck, Sergei A.; Evseev, Ivan
2013-01-01
The transportation of energetic ions in bulk matter is of direct interest in several areas including shielding against ions originating from either space radiations or terrestrial accelerators, cosmic ray propagation studies in galactic medium, or radiobiological effects resulting from the work place or clinical exposures. For carcinogenesis, terrestrial radiation therapy, and radiobiological research, knowledge of beam composition and interactions is necessary to properly evaluate the effects on human and animal tissues. For the proper assessment of radiation exposures both reliable transport codes and accurate input parameters are needed. In the last years efforts have been increasing in order to develop more effective models to describe and predict the damages induced by radiation in electronic devices. In this sense, the interaction of protons with those devices, particularly which operate in space, is a topic of paramount importance, mainly because although the majority of them are made with silicon, experimental data on p+Si nuclear processes is very sparse. In this work we have used a new quite sophisticated Monte Carlo multicollisional intranuclear cascade (MCMC) code for pre-equilibrium emission, plus de-excitation of residual nucleus by two ways: evaporation of particles (mainly nucleons, but also composites) and possibly fragmentation/fission in the case of heavy residues, in order to study some observable of nuclear interaction of protons between 100-200 MeV in a 28 Si target. The code has been developed with very recent improvements that take into account Pauli blocking effects in a novel and more precise way, as well as a more rigorous energy balance, an energy stopping time criterion for pre-equilibrium emission and the inclusion of deuteron, triton and 3He emissions in the evaporation step, which eventually concurs with fragmentation/break-up stage. The fragment mass distributions, as well as the multiplicities and the spectra of secondary particles
Strain Limits within the Scope of the Integrity Assessment of Piping Systems
International Nuclear Information System (INIS)
Mutz, Alexander
2008-01-01
Allowable stresses in nuclear power plant piping resulting from loading conditions to be considered in Germany are determined on the basis of the German Safety Standards of the Nuclear Safety Standards Commission, KTA. The limitation of the different stress categories within the analysis of the mechanical behaviour is based on a linear elastic material behaviour. Because of the ductile material used in high energy nuclear piping, a more realistic assessment can be performed on the basis of allowable strains using elastic plastic material behaviour. In the present work comparison between the analysis of piping systems considering the elastic material model and the actual elastic plastic material behaviour is performed. The possibilities of allocating plastic strains to calculated elastic stresses is discussed. A parametric study on straight pipes with the actual elastic plastic material model under pure bending is the basis of deriving the elastic plastic strains for the calculated elastic stresses. Strain limits are suggested which correspond to the different stress categories. The aim is to utilize the deformation possibilities of ductile materials used in German nuclear piping and the allocation of maximum strains to different load categories. Keywords: strain limit, ductile material, stress category. (author)
Strain Limits within the Scope of the Integrity Assessment of Piping Systems
Energy Technology Data Exchange (ETDEWEB)
Mutz, Alexander [EnBW, Durlacher Allee 93, Karlsruhe 76131 (Germany)
2008-07-01
Allowable stresses in nuclear power plant piping resulting from loading conditions to be considered in Germany are determined on the basis of the German Safety Standards of the Nuclear Safety Standards Commission, KTA. The limitation of the different stress categories within the analysis of the mechanical behaviour is based on a linear elastic material behaviour. Because of the ductile material used in high energy nuclear piping, a more realistic assessment can be performed on the basis of allowable strains using elastic plastic material behaviour. In the present work comparison between the analysis of piping systems considering the elastic material model and the actual elastic plastic material behaviour is performed. The possibilities of allocating plastic strains to calculated elastic stresses is discussed. A parametric study on straight pipes with the actual elastic plastic material model under pure bending is the basis of deriving the elastic plastic strains for the calculated elastic stresses. Strain limits are suggested which correspond to the different stress categories. The aim is to utilize the deformation possibilities of ductile materials used in German nuclear piping and the allocation of maximum strains to different load categories. Keywords: strain limit, ductile material, stress category. (author)
Energy metabolism after U.V.-irradiation in a sensitive yeast strain
International Nuclear Information System (INIS)
Kiefer, J.
1976-01-01
Stationary-phase cells of an excision-repair deficient diploid yeast (strain 2094) were UV-irradiated at exposures of up to 440 erg mm -2 and then resuspended in fresh medium. Measurements of energy metabolism per cell at periods of up to 6 hours after irradiation showed that cellular respiration was increased for all doses tested from about 3 hours after exposure, whereas fermentation did not start before about 2 hours after irradiation, never significantly exceeded control values and was markedly inhibited by the higher doses. The results suggest that respiration is under nuclear control, since a mutation in one gene is thought to be the only difference between this strain and the wild-type. The D 0 value of about 360 erg mm -2 found for the relative cellular fermentation at 2 hours after irradiation was used to give an estimate of the size of the structural gene involved, of about 3000 nucleotides, or a protein with 1000 amino-acid residues, compatible with the molecular weight of alcohol dehydrogenase. Fermentation can therefore be inhibited in this sensitive strain by lesions in the structural gene of a key enzyme. Since respiration was increased even more in repair-deficient than in repair-proficient strains, it must be assumed that higher energy metabolism is not linked to the repair process, but rather reflects a general disturbance in cellular regulation. (U.K.)
Energy Technology Data Exchange (ETDEWEB)
Novikov, I. I.; Karachinsky, L. Ya. [Connector Optics LLC (Russian Federation); Kolodeznyi, E. S.; Bougrov, V. E. [National Research University of Information Technologies, Mechanics and Optics (Russian Federation); Kurochkin, A. S.; Gladyshev, A. G.; Babichev, A. V. [Connector Optics LLC (Russian Federation); Gadzhiev, I. M.; Buyalo, M. S. [National Research University of Information Technologies, Mechanics and Optics (Russian Federation); Zadiranov, Yu. M.; Usikova, A. A., E-mail: anton@beam.ioffe.ru; Shernyakov, Yu. M. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Savelyev, A. V.; Nyapshaev, I. A. [National Research University of Information Technologies, Mechanics and Optics (Russian Federation); Egorov, A. Yu. [Connector Optics LLC (Russian Federation)
2016-10-15
The results of experimental studies of the gain properties of “thin” (3.2 nm thick) elastically strained InGaAs/InGaAlAs quantum wells emitting in the near-infrared spectral region near 1550 nm are presented. The results of studying the threshold and gain characteristics of stripe laser diodes with active regions based on “thin” quantum wells with a lattice–substrate mismatch of +1.0% show that the quantum wells under study exhibit a high modal gain of 11 cm{sup –1} and a low transparency current density of 46 A/cm{sup 2} per quantum well.
Liu, Huanlin; Yin, Yarui; Chen, Yong
2017-07-01
In order to address the problem of optimizing the spectrum resources and power consumption in elastic optical networks (EONs), we investigate the potential gains by jointly employing the light-tree splitting and traffic grooming for multicast requests. An energy-efficient multicast traffic grooming strategy based on light-tree splitting (EED-MTGS-LS) is proposed in this paper. Firstly, we design a traffic pre-processing mechanism to decide the multicast requests' routing order, which considers the request's bandwidth requirement and physical hops synthetically. Then, by dividing a light-tree to some sub-light-trees and grooming the request to these sub-light-trees, the light-tree sharing ratios of multicast requests can be improved. What's more, a priority scheduling vector is constructed, which aims to improve the success rate of spectrum assignment for grooming requests. Finally, a grooming strategy is designed to optimize the total power consumption by reducing the use of transponders and IP routers during routing. Simulation results show that the proposed strategy can significantly improve the spectrum utilization and save the power consumption.
Yokoyama, Naoto; Takaoka, Masanori
2014-12-01
A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.
Reliability assessment of a bi-material notch: Strain energy density factor approach
Czech Academy of Sciences Publication Activity Database
Klusák, Jan; Knésl, Zdeněk
2010-01-01
Roč. 53, č. 2 (2010), s. 89-93 ISSN 0167-8442 R&D Projects: GA ČR GAP108/10/2049; GA ČR GA101/08/0994 Institutional research plan: CEZ:AV0Z20410507 Keywords : crack initiation * bi-material notch * strain energy density factor Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 1.073, year: 2010
Bazant, Zdenek P; Caner, Ferhun C
2013-11-26
Although there exists a vast literature on the dynamic comminution or fragmentation of rocks, concrete, metals, and ceramics, none of the known models suffices for macroscopic dynamic finite element analysis. This paper outlines the basic idea of the macroscopic model. Unlike static fracture, in which the driving force is the release of strain energy, here the essential idea is that the driving force of comminution under high-rate compression is the release of the local kinetic energy of shear strain rate. The density of this energy at strain rates >1,000/s is found to exceed the maximum possible strain energy density by orders of magnitude, making the strain energy irrelevant. It is shown that particle size is proportional to the -2/3 power of the shear strain rate and the 2/3 power of the interface fracture energy or interface shear stress, and that the comminution process is macroscopically equivalent to an apparent shear viscosity that is proportional (at constant interface stress) to the -1/3 power of this rate. A dimensionless indicator of the comminution intensity is formulated. The theory was inspired by noting that the local kinetic energy of shear strain rate plays a role analogous to the local kinetic energy of eddies in turbulent flow.
A Membrane Model from Implicit Elasticity Theory
Freed, A. D.; Liao, J.; Einstein, D. R.
2014-01-01
A Fungean solid is derived for membranous materials as a body defined by isotropic response functions whose mathematical structure is that of a Hookean solid where the elastic constants are replaced by functions of state derived from an implicit, thermodynamic, internal-energy function. The theory utilizes Biot’s (1939) definitions for stress and strain that, in 1-dimension, are the stress/strain measures adopted by Fung (1967) when he postulated what is now known as Fung’s law. Our Fungean membrane model is parameterized against a biaxial data set acquired from a porcine pleural membrane subjected to three, sequential, proportional, planar extensions. These data support an isotropic/deviatoric split in the stress and strain-rate hypothesized by our theory. These data also demonstrate that the material response is highly non-linear but, otherwise, mechanically isotropic. These data are described reasonably well by our otherwise simple, four-parameter, material model. PMID:24282079
Zhang, Zhan; Wendt, Scott; Cosentino, Nicholas; Bond, Leonard J.
2018-04-01
Limited by photon energy, and penetration capability, traditional X-ray diffraction (XRD) strain measurements are only capable of achieving a few microns depth due to the use of copper (Cu Kα1) or molybdenum (Mo Kα1) characteristic radiation. For deeper strain depth profiling, destructive methods are commonly necessary to access layers of interest by removing material. To investigate deeper depth profiles nondestructively, a laboratory bench-top high-energy X-ray diffraction (HEXRD) system was previously developed. This HEXRD method uses an industrial 320 kVp X-Ray tube and the Kα1 characteristic peak of tungsten, to produces a higher intensity X-ray beam which enables depth profiling measurement of lattice strain. An aluminum sample was investigated with deformation/load provided using a bending rig. It was shown that the HEXRD method is capable of strain depth profiling to 2.5 mm. The method was validated using an aluminum sample where both the HEXRD method and the traditional X-ray diffraction method gave data compared with that obtained using destructive etching layer removal, performed by a commercial provider. The results demonstrate comparable accuracy up to 0.8 mm depth. Nevertheless, higher attenuation capabilities in heavier metals limit the applications in other materials. Simulations predict that HEXRD works for steel and nickel in material up to 200 µm, but experiment results indicate that the HEXRD strain profile is not practical for steel and nickel material, and the measured diffraction signals are undetectable when compared to the noise.
Tuning the energy gap of bilayer α-graphyne by applying strain and electric field
Yang, Hang; Wu, Wen-Zhi; Jin, Yu; Wan-Lin, Guo
2016-02-01
Our density functional theory calculations show that the energy gap of bilayer α-graphyne can be modulated by a vertically applied electric field and interlayer strain. Like bilayer graphene, the bilayer α-graphyne has electronic properties that are hardly changed under purely mechanical strain, while an external electric field can open the gap up to 120 meV. It is of special interest that compressive strain can further enlarge the field induced gap up to 160 meV, while tensile strain reduces the gap. We attribute the gap variation to the novel interlayer charge redistribution between bilayer α-graphynes. These findings shed light on the modulation of Dirac cone structures and potential applications of graphyne in mechanical-electric devices. Project supported by the National Key Basic Research Program of China (Grant Nos. 2013CB932604 and 2012CB933403), the National Natural Science Foundation of China (Grant Nos. 51472117 and 51535005), the Research Fund of State Key Laboratory of Mechanics and Control of Mechanical Structures, China (Grant No. 0414K01), the Nanjing University of Aeronautics and Astronautics (NUAA) Fundamental Research Funds, China (Grant No. NP2015203), and the Priority Academic Program Development of Jiangsu Higher Education Institutions.
International Nuclear Information System (INIS)
Bondarenko, S.G.; Burov, V.V.; Hamamoto, N.; Manabe, Y.; Hosaka, A.; Toki, H.
2005-01-01
Recent results obtained by the application of the Bethe-Salpeter approach to the analysis of elastic electron-deuteron scattering with the separable NN kernel are presented. We analyze the impact of the P waves (negative-energy components) on the electromagnetic properties of the deuteron and compare it with experimental data. It was shown that the contribution of the P waves must be taken into account to explain tensor polarization and charge form factor of the deuteron
Elasticity of Hard-Spheres-And-Tether Systems
International Nuclear Information System (INIS)
Farago, O.; Kantor, Y.
1999-01-01
Physical properties of a large class of systems ranging from noble gases to polymers and rubber are primarily determined by entropy, while the internal energy plays a minor role. Such systems can be conveniently modeled and numerically studied using ''hard' (i.e., ''infinity-or-zero'') potentials, such as hard sphere repulsive interactions, or inextensible (''tether'') bonds which limit the distance between the bonded monomers, but have zero energy at all permitted distances. The knowledge of elastic constants is very important for understanding the behavior of entropy-dominated systems. Computational methods for determination of the elastic constants in such systems are broadly classified into ''strain'' methods and (fluctuation methods. In the former, the elastic constants are extracted from stress-strain relations, while in the latter they are determined from measurements of stress fluctuations. The fluctuation technique usually enables more accurate and well-controlled determination of the elastic constants since in this method the elastic constants are computed directly from simulations of the un strained system with no need to deform the simulation cell and perform numerical differentiations. For central forces systems, the original ''fluctuation'' formalism can be applied provided the pair potential is twice differentiable. We have extended this formalism to apply to hard-spheres-and-tether models in which this requirement is not fulfilled. We found that for such models the components of the tensor of elastic constants can be related to (two-, three- and four-point) probability densities of contacts between hard spheres and stretched bonds. We have tested our formalism on simple (phantom networks and three-dimensional hard spheres systems
Energy Technology Data Exchange (ETDEWEB)
Manning, Gerald S., E-mail: jerrymanning@rcn.com [Department of Chemistry and Chemical Biology, Rutgers University, 610 Taylor Road, Piscataway, New Jersey 08854-8087 (United States)
2015-09-14
We give a contemporary and direct derivation of a classical, but insufficiently familiar, result in the theory of linear elasticity—a representation for the energy of a stressed elastic rod with central axis that intrinsically takes the shape of a general space curve. We show that the geometric torsion of the space curve, while playing a crucial role in the bending energy, is physically unrelated to the elastic twist. We prove that the twist energy vanishes in the lowest-energy states of a rod subject to constraints that do not restrict the twist. The stretching and contraction energies of a free helical spring are computed. There are local high-energy minima. We show the possibility of using the spring to model the chirality of DNA. We then compare our results with an available atomic level energy simulation that was performed on DNA unconstrained in the same sense as the free spring. We find some possible reflections of springlike behavior in the mechanics of DNA, but, unsurprisingly, the base pairs lend a material substance to the core of DNA that a spring does not capture.
Manning, Gerald S.
2015-09-01
We give a contemporary and direct derivation of a classical, but insufficiently familiar, result in the theory of linear elasticity—a representation for the energy of a stressed elastic rod with central axis that intrinsically takes the shape of a general space curve. We show that the geometric torsion of the space curve, while playing a crucial role in the bending energy, is physically unrelated to the elastic twist. We prove that the twist energy vanishes in the lowest-energy states of a rod subject to constraints that do not restrict the twist. The stretching and contraction energies of a free helical spring are computed. There are local high-energy minima. We show the possibility of using the spring to model the chirality of DNA. We then compare our results with an available atomic level energy simulation that was performed on DNA unconstrained in the same sense as the free spring. We find some possible reflections of springlike behavior in the mechanics of DNA, but, unsurprisingly, the base pairs lend a material substance to the core of DNA that a spring does not capture.
International Nuclear Information System (INIS)
Swol, R.W. van.
1985-01-01
The transformation of the CERN Super Proton Synchrotron (SPS) from a fixed target machine into a colliding beam facility allowed the study of antiproton-proton scattering at a centre-of-mass (CM) energy of 546 GeV. This thesis describes the measurement of antiproton-proton elastic scattering and the antiproton-proton total cross section, sigmasub(tot)(anti pp), at the CERN anti pp Collider. The aim of the experiment is to establish the considerable rise with energy of the total cross section, which was predicted after the discovery of rising proton-proton total cross sections at the CERN Intersecting Storage Rings (ISR), covering an energy range of 20-60 GeV. The experimental method used for measuring sigmasub(tot)(anti pp) with an accuracy of 1-2% consists of the simultaneous measurement of both the elastic scattering event rate at small scattering angles and the inelastic interaction rate. Using the optical theorem, the total and the elastic cross sections can then be obtained without a determination of the machine luminosity. (Auth.)
International Nuclear Information System (INIS)
Delbar, T.; Gregoire, G.; Paic, G.; Ceuleneer, R.; Michel, F.; Vanderpoorten, R.; Budzanowski, A.; Dabrowski, H.; Freindl, L.; Grotowski, K.; Micek, S.; Planeta, R.; Strzalkowski, A.; Eberhard, K.A.
1978-01-01
Angular distributions for α particle elastic scattering by /sup 40,44/Ca and excitation of the 3.73 MeV 3 - collective state of 40 Ca were measured for incident energies ranging from 40 to 62 MeV. An extensive optical model analysis of these elastic scattering cross sections and other available data, using squared Woods-Saxon form factors, results in potentials with fixed geometry for both real and imaginary parts and depths with smooth energy behavior over a broad incident energy range. These results are discussed in the frame of the semi-classical approximation developed by Brink and Takigawa. The sensitiveness of the calculated elastic scattering cross sections to the real part of the potentials as a function of the projectile-target distance has been investigated by means of a notch test. Distorted-wave Born-approximtion calculations for the excitation of the 3.73 MeV 3 - state of 40 Ca are presented
International Nuclear Information System (INIS)
Dina Al Akhrass; Bruchon, Julien; Drapier, Sylvain; Fayolle, Sebastien
2014-01-01
This paper deals with the treatment of incompressibility in solid mechanics in finite-strain elasto-plasticity. A finite-strain model proposed by Miehe, Apel and Lambrecht, which is based on a logarithmic strain measure and its work-conjugate stress tensor is chosen. Its main interest is that it allows for the adoption of standard constitutive models established in a small-strain framework. This model is extended to take into account the plastic incompressibility constraint intrinsically. In that purpose, an extension of this model to a three-field mixed finite element formulation is proposed, involving displacements, a strain variable and pressure as nodal variables with respect to standard finite element. Numerical examples of finite-strain problems are presented to assess the performance of the formulation. To conclude, an industrial case for which the classical under-integrated elements fail is considered. (authors)
The internal strain parameter of gallium arsenide measured by energy-dispersive X-ray diffraction
International Nuclear Information System (INIS)
Cousins, C.S.G.; Sheldon, B.J.; Webster, G.E.; Gerward, L.; Selsmark, B.; Staun Olsen, J.
1989-01-01
The internal strain parameter of GaAs has been measured by observing the stress-dependence of the integrated intensity of the weak 006 reflection, with the compressive stress along the [1anti 10] axis. An energy-dispersive technique was employed so that the reflection could be obtained at a photon energy close to the minimum in the structure factor, thereby approaching closely the strictly-forbidden condition that applies at any energy in the diamond structure. A value anti A=-0.138±0.005, equivalent to a bond-bending parameter ζ=0.55=0.02, has been found. This is in good agreement with recent theoretical calculations and indirect determinations related to the bandstructure of GaAs. (orig.)
P-barp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy
International Nuclear Information System (INIS)
Islam, M.M.; Fearnley, T.; Guillaud, J.P.
1984-01-01
Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range √s approx. (10-1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in p-barp and pp differential cross-sections. As energy increases beyond the ISR range (√s = (23-62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between p-barp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of p-barp and pp differential cross-sections at future collider energies √s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the p-barp differential cross-section at the ISR and SPS collider in the abs (t)-range (0.5-2.0) (GeV) 2 is stressed
anti pp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy
Energy Technology Data Exchange (ETDEWEB)
Islam, M.M. (Connecticut Univ., Storrs (USA). Dept. of Physics); Fearnley, T. (University Coll., London (UK). Dept. of Physics and Astronomy); Guillaud, J.P. (Grenoble-1 Univ., 74 - Annecy (France). Lab. de Physique des Particules)
1984-06-21
Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range ..sqrt..anti s approx.= (10/1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in anti pp and pp differential cross-sections. As energy increases beyond the ISR range (..sqrt..anti s = (23/62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between anti pp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of anti pp and pp differential cross-sections at future collider energies ..sqrt..s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the anti pp differential cross-section at the ISR and SPS collider in the vertical stroketvertical stroke-range (0.5/2.0) (GeV)/sup 2/ is stressed.
P-barp and pp elastic scattering from 10 GeV to 1000 GeV centre-of-mass energy
Energy Technology Data Exchange (ETDEWEB)
Islam, M.M. (Connecticut Univ., Storrs (USA). Dept. of Physics); Fearnley, T. (University Coll., London (UK). Dept. of Physics and Astronomy); Guillaud, J.P. (L.A.P.P. - BP909, 74019 Annecy-Le-Vieux Cedex, France)
1984-06-21
Antiproton-proton and proton-proton elastic scattering are studied simultaneously over the energy range ..sqrt..s approx. (10-1000) GeV in a nucleon valence core model proposed earlier. The scattering is described as primarily due to two processes: diffraction and hard scattering. The latter originates from the scattering of a nucleon core off another core. Destructive interference between the two processes produces dips in p-barp and pp differential cross-sections. As energy increases beyond the ISR range (..sqrt..s = (23-62) GeV), the dips get filled up, and eventually transform into shoulders or breaks at collider energies. Differences between p-barp and pp differential cross-sections persist even at collider energies. Comparison with ISR data shows that the model provides a quantitative description of pp elastic scattering in this energy range. Predictions of p-barp and pp differential cross-sections at future collider energies ..sqrt..s = 800 and 2000 GeV are given. In order to distinguish between competing models, need for measuring the p-barp differential cross-section at the ISR and SPS collider in the abs (t)-range (0.5-2.0) (GeV)/sup 2/ is stressed.
A hyper elasticity method for interactive virtual design of hearing aids
DEFF Research Database (Denmark)
Darkner, Sune; Erleben, Kenny
2011-01-01
We present a computational efficient method for isotropic hyper elasticity based on functional analysis. By selecting a class of shape functions, we arrive at a computational scheme which yields very sparse tensors. This enables fast computations of the hyper elastic energy potential and its...... derivatives. We achieve efficiency and performance through the use of shape functions that are linear in their parameters and through rotation into the eigenspace of the right Cauchy–Green strain tensor. This makes near real time evaluation of hyper elasticity of complex meshes on CPU relatively easy...... to implement. The approach does not rely on a specific shape function or material model but offers a general framework for isotropic hyper elasticity. The method is aimed at interactive and accurate non-linear hyper elastic modeling for a wide range of industrial virtual design applications, which we exemplify...
Feng, Guo-Hua; Huang, Wei-Lun
2014-12-01
This paper presents a smart tuning-fork-shaped ionic polymer metal composite (IPMC) clamping actuator for biomedical applications. The two fingers of the actuator, which perform the clamping motion, can be electrically controlled through a unique electrode design on the IPMC material. The generated displacement or strain of the fingers can be sensed using an integrated soft strain-gage sensor. The IPMC actuator and associated soft strain gage were fabricated using a micromachining technique. A 13.5×4×2 mm(3) actuator was shaped from Nafion solution and a selectively grown metal electrode formed the active region. The strain gage consisted of patterned copper foil and polyethylene as a substrate. The relationship between the strain gage voltage output and the displacement at the front end of the actuator's fingers was characterized. The equivalent Young's modulus, 13.65 MPa, of the soft-strain-gage-integrated IPMC finger was analyzed. The produced clamping force exhibited a linear increasing rate of 1.07 mN/s, based on a dc driving voltage of 7 V. Using the developed actuator to clamp soft matter and simultaneously acquire its Young's modulus was achieved. This demonstrated the feasibility of the palpation function and the potential use of the actuator in minimally invasive surgery. Copyright © 2014 Elsevier B.V. All rights reserved.
Zhang, Qianfan; Cui, Yi; Wang, Enge
2011-01-01
Silicon nanowires (SiNWs) have recently been shown to be promising as high capacity lithium battery anodes. SiNWs can be grown with their long axis along several different crystallographic directions. Due to distinct atomic configuration and electronic structure of SiNWs with different axial orientations, their lithium insertion behavior could be different. This paper focuses on the characteristics of single Li defects, including binding energy, diffusion barriers, and dependence on uniaxial strain in [110], [100], [111], and [112] SiNWs. Our systematic ab initio study suggests that the Si-Li interaction is weaker when the Si-Li bond direction is aligned close to the SiNW long axis. This results in the [110] and [111] SiNWs having the highest and lowest Li binding energy, respectively, and it makes the diffusion barrier along the SiNW axis lower than other pathways. Under external strain, it was found that [110] and [001] SiNWs are the most and least sensitive, respectively. For diffusion along the axial direction, the barrier increases (decreases) under tension (compression). This feature results in a considerable difference in the magnitude of the energy barrier along different diffusion pathways. © 2011 American Chemical Society.
Zhang, Qianfan
2011-05-19
Silicon nanowires (SiNWs) have recently been shown to be promising as high capacity lithium battery anodes. SiNWs can be grown with their long axis along several different crystallographic directions. Due to distinct atomic configuration and electronic structure of SiNWs with different axial orientations, their lithium insertion behavior could be different. This paper focuses on the characteristics of single Li defects, including binding energy, diffusion barriers, and dependence on uniaxial strain in [110], [100], [111], and [112] SiNWs. Our systematic ab initio study suggests that the Si-Li interaction is weaker when the Si-Li bond direction is aligned close to the SiNW long axis. This results in the [110] and [111] SiNWs having the highest and lowest Li binding energy, respectively, and it makes the diffusion barrier along the SiNW axis lower than other pathways. Under external strain, it was found that [110] and [001] SiNWs are the most and least sensitive, respectively. For diffusion along the axial direction, the barrier increases (decreases) under tension (compression). This feature results in a considerable difference in the magnitude of the energy barrier along different diffusion pathways. © 2011 American Chemical Society.
Exploring the tensile strain energy absorption of hybrid modified epoxies containing soft particles
International Nuclear Information System (INIS)
Abadyan, M.; Bagheri, R.; Kouchakzadeh, M.A.; Hosseini Kordkheili, S.A.
2011-01-01
Research highlights: → Two epoxy systems have been modified by combination of fine and coarse modifiers. → While both hybrid systems reveal synergistic K IC , no synergism is observed in tensile test. → It is found that coarse particles induce stress concentration in hybrid samples. → Stress concentration leads to fracture of samples at lower energy absorption levels. -- Abstract: In this paper, tensile strain energy absorption of two different hybrid modified epoxies has been systematically investigated. In one system, epoxy has been modified by amine-terminated butadiene acrylonitrile (ATBN) and hollow glass spheres as fine and coarse modifiers, respectively. The other hybrid epoxy has been modified by the combination of ATBN and recycled Tire particles. The results of fracture toughness measurement of blends revealed synergistic toughening for both hybrid systems in some formulations. However, no evidence of synergism is observed in tensile test of hybrid samples. Scanning electron microscope (SEM), transmission optical microscope (TOM) and finite element (FEM) simulation were utilized to study deformation mechanisms of hybrid systems in tensile test. It is found that coarse particles induce stress concentration in hybrid samples. This produces non-uniform strain localized regions which lead to fracture of hybrid samples at lower tensile loading and energy absorption levels.
Integrodifferential relations in linear elasticity
Kostin, Georgy V
2012-01-01
This work treats the elasticity of deformed bodies, including the resulting interior stresses and displacements.It also takes into account that some of constitutive relations can be considered in a weak form. To discuss this problem properly, the method of integrodifferential relations is used, and an advanced numerical technique for stress-strain analysis is presented and evaluated using various discretization techniques. The methods presented in this book are of importance for almost all elasticity problems in materials science and mechanical engineering.
International Nuclear Information System (INIS)
Grigoryan, L.A.; Shakhbazyan, V.A.
1976-01-01
Determined are differential cross sections for K meson elastic scattering on a 4 He nucleus for the energies of an incident particle equal to 30 and 50 GeV, the total cross section in the range from 10 to 10 3 GeV and the di(GeV/c) 2 versus energy in the range 10-100 GeV. The calculation is carried out with the eikonal and quasieikonal models of the complex moment theory. The effects of inelastic screening are shown to be very essential
International Nuclear Information System (INIS)
Nichitiu, F.; Falomkin, I.V.; Sapozhnikov, M.G.; Shcherbakov, Yu.A.; Piragino, G.
1981-06-01
In the 24 MeV-260 MeV kinetic energy interval, the energy dependent phase shift analysis of π 4 He elastic scattering is done. The eneray dependence is given by the rational fraction approximants of the partial S matrix. The search for the stable S matrix zero-pole pairs in the k and √s complex plane give some proofs for the existence of the (π 4 He) excited states in the S, P and probably D partial waves. (authors)
Gurbich, A. F.; Bokhovko, M. V.
2018-04-01
The alpha elastic scattering cross-sections for Ni, Cu, and Y were measured at the energies above the onset of the non-Rutherford scattering. The obtained experimental data along with data from literature were incorporated into the theoretical analysis in the framework of the optical model. The optimization of the model parameters provided a basis for the calculations of the differential cross-sections for Z = 28-38 elements in the energy range up to 10 MeV. The obtained cross sections were made available for common use through the SigmaCalc web site at http://sigmacalc.iate.obninsk.ru/.
A high energy microscope for local strain measurements within bulk materials
DEFF Research Database (Denmark)
Lienert, U.; Poulsen, H.F.; Martins, R.V.
2000-01-01
A novel diffraction technique for local, three dimensional strain scanning within bulk materials is presented. The technique utilizes high energy, micro-focussed synchrotron radiation which can penetrate several millimeters into typical metals. The spatial resolution can be as narrow as 1 mum...... in one dimension and in three dimensions about 5x10x100 mum(3) Bulk properties are probed non-destructively and in-situ measurements during thermo-mechanical processing are feasible. A dedicated experimental station has been constructed at the ID11 beamline of the European Synchrotron Radiation Facility...
Proton-proton elastic scattering at the LHC energy of $\\sqrt{s}$ = 7 TeV
Antchev, G.; Aspell, P.; Atanassov, I.; Avati, V.; Baechler, J.; Berardi, V.; Berretti, M.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.S.; Calicchio, M.; Catanesi, M.G.; Covault, C.; Csanad, M.
2011-01-01
Proton-proton elastic scattering has been measured by the TOTEM experiment at the CERN Large Hadron Collider at √ s = 7 TeV in dedicated runs with the Roman Pot detectors placed as close as seven times the transverse beam size (σbeam) from the outgoing beams. After careful study of the accelerator optics and the detector alignment, |t| , the square of four-momentum transferred in the elastic scattering process, has been determined with an uncertainty of δ t = 0.1 GeV √ |t|. In this letter the...
International Nuclear Information System (INIS)
Budzanowski, A.; Dabrowski, H.; Freindl, L.; Grotowski, K.; Micek, S.; Planeta, R.; Strzalkowski, A.; Bosman, M.; Leleux, P.; Macq, P.; Meulders, J.P.; Pirart, C.
1978-01-01
The differential cross sections for α particles elastically and inelastically scattered from 5 8Ni (at 29, 34, 38, and 58 MeV) and elastically scattered from 6 0Ni (at 29 and 34 MeV), are measured together with excitation functions in the 25--38 MeV region at 178.5 0 lab. These data together with the data of 26.5, 32.3, 104, and 139 MEV for 5 8Ni and 32.3 and 104 MeV for 6 0Ni from other sources were analyzed using an optical model with volume and surface absorptions and the Saxon-Woods square form factors. The analysis yielded energy dependent depths of both real and imaginary parts of the potential and constant geometric parameters. The analytical expressions for depths of the real and both absorption potentials are obtained. The coupled channel calculations using the above optical potential were performed for the first excited state of 5 8Ni. Both elastic scattering data and coupling with the first excited state of 5 8Ni are well reproduced using the above potential in the wide scattering energy range
International Nuclear Information System (INIS)
Vinodkumar, Minaxi; Bhutadia, Harshad; Antony, Bobby; Mason, Nigel
2011-01-01
This paper reports computational results of the total cross sections for electron impact on H 2 CO and HCOOH over a wide range of electron impact energies from 0.01 eV to 2 keV. The total cross section is presented as sum of the elastic and electronic excitation cross sections for incident energies. The calculation uses two different methodologies, below the ionization threshold of the target the cross section is calculated using the UK molecular R-matrix code through the Quantemol-N software package while cross sections at higher energies are evaluated using the spherical complex optical potential formalism. The two methods are found to be consistent at the transition energy (∼15 eV). The present results are, in general, found to be in good agreement with previous experimental and theoretical results (wherever available) and, thus, the present results can serve as a benchmark for the cross section over a wide range of energy.
Strain relaxation of CdTe on Ge studied by medium energy ion scattering
Energy Technology Data Exchange (ETDEWEB)
Pillet, J.C., E-mail: jean-christophe.pillet@cea.fr [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA, LETI, Département Optique et Photonique, F38054 Grenoble (France); Pierre, F. [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA, LETI, Service de Caractérisation des Matériaux et Composants, F38054 Grenoble (France); Jalabert, D. [Univ. Grenoble Alpes, CEA, LETI, MINATEC campus, F38000 Grenoble (France); CEA-INAC/UJF-Grenoble 1 UMR-E, SP2M, LEMMA, Minatec Grenoble F-38054 (France)
2016-10-01
We have used the medium energy ion scattering (MEIS) technique to assess the strain relaxation in molecular-beam epitaxial (MBE) grown CdTe (2 1 1)/Ge (2 1 1) system. A previous X-ray diffraction study, on 10 samples of the same heterostructure having thicknesses ranging from 25 nm to 10 μm has allowed the measurement of the strain relaxation on a large scale. However, the X-ray diffraction measurements cannot achieve a stress measurement in close proximity to the CdTe/Ge interface at the nanometer scale. Due to the huge lattice misfit between the CdTe and Ge, a high degree of disorder is expected at the interface. The MEIS in channeling mode is a good alternative in order to profile defects with a high depth resolution. For a 21 nm thick CdTe layer, we observed, at the interface, a high density of Cd and/or Te atoms moved from their expected crystallographic positions followed by a rapid recombination of defects. Strain relaxation mechanisms in the vicinity of the interface are discussed.
Strain-Induced Enhancement of the Electron Energy Relaxation in Strongly Correlated Superconductors
Directory of Open Access Journals (Sweden)
C. Gadermaier
2014-03-01
Full Text Available We use femtosecond optical spectroscopy to systematically measure the primary energy relaxation rate Γ_{1} of photoexcited carriers in cuprate and pnictide superconductors. We find that Γ_{1} increases monotonically with increased negative strain in the crystallographic a axis. Generally, the Bardeen-Shockley deformation potential theorem and, specifically, pressure-induced Raman shifts reported in the literature suggest that increased negative strain enhances electron-phonon coupling, which implies that the observed direct correspondence between a and Γ_{1} is consistent with the canonical assignment of Γ_{1} to the electron-phonon interaction. The well-known nonmonotonic dependence of the superconducting critical temperature T_{c} on the a-axis strain is also reflected in a systematic dependence T_{c} on Γ_{1}, with a distinct maximum at intermediate values (∼16 ps^{−1} at room temperature. The empirical nonmonotonic systematic variation of T_{c} with the strength of the electron-phonon interaction provides us with unique insight into the role of electron-phonon interaction in relation to the mechanism of high-T_{c} superconductivity as a crossover phenomenon.
Directory of Open Access Journals (Sweden)
BOLSHAKOV V. I.
2017-03-01
Full Text Available Summary. Based on the current understanding of the piles work in clayey soils; that is forming during driving process a compacted core (compacted platform in the pile tip plane and transferring the load from the pile (from the piling foundation not through the pile tip but through the pressed core (compacted platform, the stress in the soil mass by the load applied inside the elastic half-space is determined with the change in the calculated scheme of load transferring to the “homogeneous” soil mass.
Czech Academy of Sciences Publication Activity Database
Thomasová, M.; Seiner, Hanuš; Sedlák, Petr; Frost, Miroslav; Ševčík, Martin; Szurman, I.; Kocich, R.; Drahokoupil, Jan; Šittner, Petr; Landa, Michal
2017-01-01
Roč. 123, January (2017), s. 146-156 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GP14-28306P; GA ČR GA14-15264S Institutional support: RVO:61388998 ; RVO:68378271 Keywords : shape memory alloys * polycrystals * elastic behavior Subject RIV: BM - Solid Matter Physics ; Magnetism; BM - Solid Matter Physics ; Magnetism (FZU-D) OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.); Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D) Impact factor: 5.301, year: 2016
International Nuclear Information System (INIS)
Gomes, P. R. S.; Lubian, J.; Mendes-Junior, D. R.; Faria, P. N. de; Linares, R.; Sigaud, L.; Rangel, J.; Ferreira, J. L.; Paes, B.; Cardozo, E. N.; Cortes, M. R.; Canto, L. F.; Ermamatov, M. J.; Otomar, D. R.; Ferioli, E.; Lotti, P.; Hussein, M. S.
2016-01-01
We present a brief review of the reaction mechanisms involved in collisions of weakly bound projectiles with tightly bound targets, at near-barrier energies. We discuss systematic behaviors of the data, with emphasis in fusion, breakup, nucleon transfer and elastic scattering. The dependence of the breakup cross section on the charge and mass of the target is discussed, and the influence of the breakup channel on complete fusion is investigated. For this purpose, we compare reduced fusion cross sections with a benchmark universal curve. The behaviors observed in the comparisons are explained in terms of polarization potentials and of nucleon transfer followed by breakup. The influence of the breakup process on elastic scattering is also discussed. Some apparent contradictions between results of different authors are explained and some perspectives of the field are presented. (author)
Elastic constants of stressed and unstressed materials in the phase-field crystal model
Wang, Zi-Le; Huang, Zhi-Feng; Liu, Zhirong
2018-04-01
A general procedure is developed to investigate the elastic response and calculate the elastic constants of stressed and unstressed materials through continuum field modeling, particularly the phase-field crystal (PFC) models. It is found that for a complete description of system response to elastic deformation, the variations of all the quantities of lattice wave vectors, their density amplitudes (including the corresponding anisotropic variation and degeneracy breaking), the average atomic density, and system volume should be incorporated. The quantitative and qualitative results of elastic constant calculations highly depend on the physical interpretation of the density field used in the model, and also importantly, on the intrinsic pressure that usually pre-exists in the model system. A formulation based on thermodynamics is constructed to account for the effects caused by constant pre-existing stress during the homogeneous elastic deformation, through the introducing of a generalized Gibbs free energy and an effective finite strain tensor used for determining the elastic constants. The elastic properties of both solid and liquid states can be well produced by this unified approach, as demonstrated by an analysis for the liquid state and numerical evaluations for the bcc solid phase. The numerical calculations of bcc elastic constants and Poisson's ratio through this method generate results that are consistent with experimental conditions, and better match the data of bcc Fe given by molecular dynamics simulations as compared to previous work. The general theory developed here is applicable to the study of different types of stressed or unstressed material systems under elastic deformation.
Korotchenkov, Oleg; Nadtochiy, Andriy; Kuryliuk, Vasyl; Wang, Chin-Chi; Li, Pei-Wen; Cantarero, Andres
2014-03-01
The efficiency of the energy conversion devices depends in many ways on the materials used and various emerging cost-effective nanomaterials have promised huge potentials in highly efficient energy conversion. Here we show that thermoelectric voltage can be enhanced by a factor of 3 using layer-cake growth of Ge quantum dots through thermal oxidation of SiGe layers stacked in SiO2/Si3N4 multilayer structure. The key to achieving this behavior has been to strain the Ge/Si interface by Ge dots migrating to Si substrate. Calculations taking into account the carrier trapping in the dot with a quantum transmission into the neighboring dot show satisfactory agreement with experiments above ≈200 K. The results may be of interest for improving the functionality of thermoelectric devices based on Ge/Si.
Strain control of Urbach energy in Cr-doped PrFeO{sub 3}
Energy Technology Data Exchange (ETDEWEB)
Kumar, Anil; Warshi, M.K.; Mishra, Vikash; Saxena, Shailendra K.; Kumar, Rajesh; Sagdeo, Pankaj R. [Indian Institute of Technology Indore, Material Research Laboratory, Discipline of Physics and MEMS, Indore (India)
2017-09-15
Polycrystalline samples of PrFe{sub 1-x}Cr{sub x}O{sub 3} having average particle size of ∝90 nm have been prepared by wet chemical route. The structural phase purity of the prepared samples is confirmed by powder X-ray diffraction followed by Rietveld refinements. It is observed that with Cr doping, the Urbach energy (E{sub u}) increases. The E{sub u} is measure of the various disorders present in the sample, such as chemical and structural. To understand the contribution to the E{sub u} due to chemical and structural disorders, we have probed the chemical and structural disorders in the samples by elemental mappings and through X-ray diffraction experiments, respectively. Elemental mapping confirms chemical homogeneity of prepared samples. It is observed that with Cr doping the crystallographic strain increases and Urbach energy shows the similar scaling. (orig.)
Gamiz-Hernandez, Ana P; Kaila, Ville R I
2016-01-28
The Photoactive Yellow Protein (PYP) is a light-driven photoreceptor, responsible for the phototaxis of halophilic bacteria. Recently, a new short-lived intermediate (pR0) was characterized in the PYP photocycle using combined time-resolved X-ray crystallography and density functional theory calculations. The pR0 species was identified as a highly contorted cis-intermediate, which is stabilized by hydrogen bonds with protein residues. Here we show by hybrid quantum mechanics/classical mechanics (QM/MM) molecular dynamics simulations, and first-principles calculations of optical properties, that the optical shifts in the early steps of the PYP photocycle originate from the conversion of light energy into molecular strain, stored in the pR0 state, and its relaxation in subsequent reaction steps. Our calculations quantitatively reproduce experimental data, which enables us to identify molecular origins of the optical shifts. Our combined approach suggests that the short-lived pR0 intermediate stores ∼1/3 of the photon energy as molecular strain, thus providing the thermodynamic driving force for later conformational changes in the protein.
Ranković, Miloš Lj.; Maljković, Jelena B.; Tökési, Károly; Marinković, Bratislav P.
2018-02-01
Measurements and calculations for electron elastic differential cross sections (DCS) of argon atom in the energy range from 40 to 300 eV are presented. DCS have been measured in the crossed beam arrangement of the electron spectrometer with an energy resolution of 0.5 eV and angular resolution of 1.5∘ in the range of scattering angles from 20∘ to 126∘. Both angular behaviour and energy dependence of DCS are obtained in a separate sets of experiments, while the absolute scale is achieved via relative flow method, using helium as a reference gas. All data is corrected for the energy transmission function, changes of primary electron beam current and target pressure, and effective path length (volume correction). DCSs are calculated in relativistic framework by expressing the Mott's cross sections in partial wave expansion. Our results are compared with other available data.
Vliet, Jurg; Wel, Steven; Dowd, Dara
2011-01-01
While it's always been possible to run Java applications on Amazon EC2, Amazon's Elastic Beanstalk makes the process easier-especially if you understand how it works beneath the surface. This concise, hands-on book not only walks you through Beanstalk for deploying and managing web applications in the cloud, you'll also learn how to use this AWS tool in other phases of development. Ideal if you're a developer familiar with Java applications or AWS, Elastic Beanstalk provides step-by-step instructions and numerous code samples for building cloud applications on Beanstalk that can handle lots
Energy Technology Data Exchange (ETDEWEB)
Morcelle, Viviane; Gomes, P.R.S.; Lubian, J.; Mendes Junior, D.R. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil); Lichtenthaeler, R.; Guimaraes, V.; Lepine-Szily, A.; Camargo, O.; Faria, P.N. de; Gasquez, L.; Morais, M.C.; Condori, R.P.; Pires, K.C.C.; Scarduelli, V. [Universidade de Sao Paulo (USP), SP (Brazil); Barioni, A. [Universidade Federal da Bahia (UFBA), Salvador, BA (Brazil); Shorto, J.M.B. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Zamora, J.C. [Technische Universitaet Darmstadt (Germany); Aguilera, E.; Martinez-Quiroz, E. [Instituto Nacional de Investigaciones Nucleares (Mexico); Kolata, J.; Jiang, H. [University of Notre Dame, IN (United States); Bechetti, F.D.; Lamm, L.O. [Michigan University, MI (United States); Lizcano, D. [Universidad Autonoma del Estado de Mexico (Mexico)
2012-07-01
Full text: Elastic scattering measurements were performed at energies around the Coulomb barrier at the Tandem Accelerators of the Sao Paulo (USP - Brazil ) and Notre Dame (UND - USA) Universities. The {sup 7}Be is a radioactive nucleus and has been produced by the reaction {sup 6}He({sup 6}Li,{sup 9}Be) and impinged on {sup 27}Al and {sup 197}Au secondary targets using a double superconducting systems RIBRAS ( USP ) and Twinsol (UND). The elastic scattering angular distributions were analyzed through the optical model calculations, using the Woods- Saxon form factors [1] and the Sao Paulo potential [2] to fit the experimental data. The total reaction cross sections were also derived and compared with others presented at the literature for other systems. In addition, a study of the nuclear potential energy dependence has been carried out in this work in the dispersion relation context. Due to the fact that {sup 7}Be has a small breakup threshold energy, the results can provide significant information of the influence of the breakup channel on the reactions involving this projectile. For this purpose, {chi}{sup 2}- data analysis with different kind of potentials were performed to identify the energy dependence of the real (V) and imaginary (W) parts of the potential. [1] L.C. Chamon et al., Phys. Rev. C 66, (2002) 014610. [2] R.D. Wood e D.S. Saxon, Phys. Rev. 95 ( 1954) 577. (author)
Chirality-dependent anisotropic elastic properties of a monolayer graphene nanosheet.
Guo, Jian-Gang; Zhou, Li-Jun; Kang, Yi-Lan
2012-04-01
An analytical approach is presented to predict the elastic properties of a monolayer graphene nanosheet based on interatomic potential energy and continuum mechanics. The elastic extension and torsional springs are utilized to simulate the stretching and angle variation of carbon-carbon bond, respectively. The constitutive equation of the graphene nanosheet is derived by using the strain energy density, and the analytical formulations for nonzero elastic constants are obtained. The in-plane elastic properties of the monolayer graphene nanosheet are proved to be anisotropic. In addition, Young's moduli, Poisson's ratios and shear modulus of the monolayer graphene nanosheet are calculated according to the force constants derived from Morse potential and AMBER force field, respectively, and they were proved to be chirality-dependent. The comparison with experimental results shows a very agreement.
Photoswitchable Dihydroazulene Macrocycles for Solar Energy Storage: The Effects of Ring Strain.
Vlasceanu, Alexandru; Frandsen, Benjamin N; Skov, Anders B; Hansen, Anne Schou; Rasmussen, Mads Georg; Kjaergaard, Henrik G; Mikkelsen, Kurt V; Nielsen, Mogens Brøndsted
2017-10-06
Efficient energy storage and release are two major challenges of solar energy harvesting technologies. The development of molecular solar thermal systems presents one approach to address these issues by tuning the isomerization reactions of photo/thermoswitches. Here we show that the incorporation of photoswitches into macrocyclic structures is a particularly attractive solution for increasing the storage time. We present the synthesis and properties of a series of macrocycles incorporating two dihydroazulene (DHA) photoswitching subunits, bridged by linkers of varying chain length. Independent of ring size, all macrocycles exhibit stepwise, light-induced, ring-opening reactions (DHA-DHA to DHA-VHF to VHF-VHF; VHF = vinylheptafulvene) with the first DHA undergoing isomerization with a similar efficiency as the uncyclized parent system while the second (DHA-VHF to VHF-VHF) is significantly slower. The energy-releasing, VHF-to-DHA, ring closures also occur in a stepwise manner and are systematically found to proceed slower in the more strained (smaller) cycles, but in all cases with a remarkably slow conversion of the second VHF to DHA. We managed to increase the half-life of the second VHF-to-DHA conversion from 65 to 202 h at room temperature by simply decreasing the ring size. A computational study reveals the smallest macrocycle to have the most energetic VHF-VHF state and hence highest energy density.
Zhang, G. L.; Zhang, G. X.; Lin, C. J.; Lubian, J.; Rangel, J.; Paes, B.; Ferreira, J. L.; Zhang, H. Q.; Qu, W. W.; Jia, H. M.; Yang, L.; Ma, N. R.; Sun, L. J.; Wang, D. X.; Zheng, L.; Liu, X. X.; Chu, X. T.; Yang, J. C.; Wang, J. S.; Xu, S. W.; Ma, P.; Ma, J. B.; Jin, S. L.; Bai, Z.; Huang, M. R.; Zang, H. L.; Yang, B.; Liu, Y.
2018-04-01
The elastic scattering angular distributions were measured for 50- and 59-MeV 17F radioactive ion beam on a 89Y target. The aim of this work is to study the effect of the breakup of the proton halo projectile on the elastic scattering angular distribution. The experimental data were analyzed by means of the optical model with the double-folding São Paulo potential for both real and imaginary parts. The theoretical calculations reproduced the experimental data reasonably well. It is shown that the method of the data analysis is correct. In order to clarify the difference observed at large angles for the 59-MeV incident energy data, Continuum-Discretized Coupled-Channels (CDCC) calculations were performed to consider the breakup coupling effect. It is found that the experimental data show the Coulomb rainbow peak and that the effect of the coupling to the continuum states is not very significant, producing only a small hindrance of the Coulomb rainbow peak and a very small enhancement of the elastic scattering angular distribution at backward angles, suggesting that the multipole response of the neutron halo projectiles is stronger than that of the proton halo systems.
International Nuclear Information System (INIS)
Golovanova, N.F.; Il'in, I.M.; Neudatchin, V.G.; Smirnov, Yu.F.; Tchuvil'sky, Yu.M.
1976-01-01
The quasi-elastic knock-out of nucleon clusters from nuclei by an incident high-energy hadron is considered within the framework of the Glauber-Sitenko multiple scattering theory. It is shown that the significant contribution to the cross section for the process comes not only from the hadron elastic scattering by a nonexcited virtual cluster but also from collisions with an excited virtual cluster, accompanied by de-excitation of this cluster. This necessitates modification of the usual theory of quasi-elastic cluster knock-out. First, the angular correlations of the knocked-out cluster and scattered hadron are no longer determined by the momentum distribution of the cluster in the nucleus. They are determined by another form factor F(q) which can be called the modified momentum distribution. Secondly, the meaning and values of the effective numbers of clusters Nsup(eff) have been changed. Thirdly, the characteristics of the processes depend not only on the modulus of momentum q, which the cluster had in the nucleus, but also on its direction relative to an incident beam. A method has been developed for the calculation of the fractional parentage coefficients, which are necessary for the calculation of the cluster knock-out from the p-shell nuclei. (Auth.)
Nonlinear elasticity in wurtzite GaN/AlN planar superlattices and quantum dots
International Nuclear Information System (INIS)
Lepkowski, S.P.; Majewski, J.A.; Jurczak, G.
2005-01-01
The elastic stiffness tensor for wurtzite GaN and AlN show a significant hydrostatic pressure dependence, which id the evidence of nonlinear elasticity of these compounds. We have examined how the pressure dependence of elastic constants for wurtzite nitrides influences elastic and piezoelectric properties of GaN/AlN planar superlattices and quantum dots. Particularly we show that built-in hydrostatic pressure, present in both quantum wells of the GaN/AlN superlattices and GaN/AlN quantum dots, increases significantly by 0.3-0.7 GPa when nonlinear elasticity is used. Consequently, the compressive volumetric strain in quantum wells and quantum dots decreases in comparison to the case of the linear elastic theory, However, the-component of the built-in electric field in the quantum wells and quantum dots increases considerably when nonlinear elasticity is taken into account. Both effects, i.e., a decrease in the compressive volumetric strain as well as an increase in the built-in electric field, decrease the band-to-band transition energies in the quantum wells and quantum dots. (author)
Contribution of elastic tissues to the mechanics and energetics of muscle function during movement.
Roberts, Thomas J
2016-01-01
Muscle force production occurs within an environment of tissues that exhibit spring-like behavior, and this elasticity is a critical determinant of muscle performance during locomotion. Muscle force and power output both depend on the speed of contraction, as described by the isotonic force-velocity curve. By influencing the speed of contractile elements, elastic structures can have a profound effect on muscle force, power and work. In very rapid movements, elastic mechanisms can amplify muscle power by storing the work of muscle contraction slowly and releasing it rapidly. When energy must be dissipated rapidly, such as in landing from a jump, energy stored rapidly in elastic elements can be released more slowly to stretch muscle contractile elements, reducing the power input to muscle and possibly protecting it from damage. Elastic mechanisms identified so far rely primarily on in-series tendons, but many structures within muscles exhibit spring-like properties. Actomyosin cross-bridges, actin and myosin filaments, titin, and the connective tissue scaffolding of the extracellular matrix all have the potential to store and recover elastic energy during muscle contraction. The potential contribution of these elements can be assessed from their stiffness and estimates of the strain they undergo during muscle function. Such calculations provide boundaries for the possible roles these springs might play in locomotion, and may help to direct future studies of the uses of elastic elements in muscle. © 2016. Published by The Company of Biologists Ltd.
International Nuclear Information System (INIS)
Sun, Chuanwang; Ouyang, Xiaoling
2016-01-01
Urbanization, one of the most obvious characteristics of economic growth in China, has an apparent “lock-in effect” on residential energy consumption pattern. It is expected that residential sector would become a major force that drives China's energy consumption after urbanization process. We estimate price and expenditure elasticities of residential energy demand using data from China's Residential Energy Consumption Survey (CRECS) that covers households at different income levels and from different regional and social groups. Empirical results from the Almost Ideal Demand System model are in accordance with the basic expectations: the demands for electricity, natural gas and transport fuels are inelastic in the residential sector due to the unreasonable pricing mechanism. We further investigate the sensitivities of different income groups to prices of the three types of energy. Policy simulations indicate that rationalizing energy pricing mechanism is an important guarantee for energy sustainable development during urbanization. Finally, we put forward suggestions on energy pricing reform in the residential sector based on characteristics of China's undergoing urbanization process and the current energy consumption situations.
International Nuclear Information System (INIS)
Fagundes, Daniel Almeida
2010-01-01
The theoretical description of high-energy elastic hadron scattering constitutes an open problem in both, the underlying quantum field theory of strong interactions (QCD) and the phenomenological context. In this work the inverse problem in elastic hadron scattering is discussed in the impact parameter and eikonal frameworks, specifically a study on the empirical extraction of the profile, the inelastic overlap and the eikonal functions, from the experimental data and some principles and high-energy theorems (model independent). The analysis is limited to elastic proton-proton scattering in the center of momentum energy interval 19.4 - 62.5 GeV. In particular, a novel representation for the Martin's Real Part Formula is introduced but without the scaling property and suitable for empirical analysis. By means of this representation, and two other parametrizations previously introduced (constrained and unconstrained), several properties of the inelastic overlap function and the imaginary part of the eikonal (opacity) in the momentum transfer space are determined, in special: (1) evidence of a peripheral effect (tail) in the inelastic overlap function in the parameter impact space above 2 fm; (2) development of analytical parametrizations for this function leading to three gaussian components with centers at 0.0, ∼0.7 and ∼1.3 fm; (3) evidence of a finite zero (change of sign) in the opacity function in the momentum transfer space; (4) development of empirical parametrization for this function consistent with form factors as a product of two monopoles with constrained masses (not a dipole type) and a term with zero; (5) detailed discussion on the determination of the opacity function in the momentum transfer space through the semi-analytical approach. The applicability of these empirical results in the development of eikonal models (mainly those inspired in QCD) is also discussed. (author)