Elastic Constants of Plane Orthotropic Elasticity
DEFF Research Database (Denmark)
Krenk, Steen
1979-01-01
to stress fields that are independent of the effective stiffness and the effective Poisson ratio, and a general transformation is described which is equivalent to a change of the stiffness ratio. These properties suggest the importance of the remaining shear parameter, that has the interesting property......The four independent material parameters of plane orthotropic elasti city are introduced as the effective stiffness, the effective Poisson ratio, the stiffness ratio and the shear parameter. It is proved that stress boundary value problems with zero resulting force on internal contours lead...
Plane strain problem in microstretch elastic solid
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
MS received 17 February 2000; revised 1 August 2003. Abstract. The eigenvalue approach is developed for the two-dimensional plane strain problem in a microstretch elastic medium. Applying Laplace and Fourier transforms, an infinite space subjected to a concentrated force is studied. The inte- gral transforms are ...
A general solution to some plane problems of micropolar elasticity
DEFF Research Database (Denmark)
Warren, William E.; Byskov, Esben
2008-01-01
We obtain a general solution to the field equations of plane micropolar elasticity for materials characterized by a hexagonal or equilateral triangular structure. These materials exhibit 3-fold symmetry in the plane and the elastic response is isotropic. Utilizing two displacement potential funct...
Control Plane Strategies for Elastic Optical Networks
DEFF Research Database (Denmark)
Turus, Ioan
Networks (EONs) concept is proposed as a solution to enable a more flexible handling of the optical capacity and allows an increase of available capacity over the existing optical infrastructure. One main requirement for enabling EONs is to have a flexible spectrum structure (i.e.Flex-Grid) which allows...... consumption. EONs offer the opportunity of deploying energy efficiency strategies, which benefit from the flexible nature of elastic optoelectronic devices. This thesis proposes and investigates different approaches for reducing power consumption based on EONs in realistic dynamic traffic scenarios....
Phase velocity and attenuation of plane waves in dissipative elastic ...
African Journals Online (AJOL)
An iteration method to find the roots of a complex transcendental equation is under scanner. This method identified as functional iteration method is being used mainly in wave propagation problems to calculate the phase velocity and the attenuation of plane harmonic waves in dissipative elastic plates. Few mathematical ...
Plane Wave-Perturbative Method for Evaluating the Effective Speed of Sound in 1D Phononic Crystals
Directory of Open Access Journals (Sweden)
J. Flores Méndez
2016-01-01
Full Text Available A method for calculating the effective sound velocities for a 1D phononic crystal is presented; it is valid when the lattice constant is much smaller than the acoustic wave length; therefore, the periodic medium could be regarded as a homogeneous one. The method is based on the expansion of the displacements field into plane waves, satisfying the Bloch theorem. The expansion allows us to obtain a wave equation for the amplitude of the macroscopic displacements field. From the form of this equation we identify the effective parameters, namely, the effective sound velocities for the transverse and longitudinal macroscopic displacements in the homogenized 1D phononic crystal. As a result, the explicit expressions for the effective sound velocities in terms of the parameters of isotropic inclusions in the unit cell are obtained: mass density and elastic moduli. These expressions are used for studying the dependence of the effective, transverse and longitudinal, sound velocities for a binary 1D phononic crystal upon the inclusion filling fraction. A particular case is presented for 1D phononic crystals composed of W-Al and Polyethylene-Si, extending for a case solid-fluid.
Recent developments in testing techniques for elastic mechanical properties of 1-D nanomaterials.
Wang, Weidong; Li, Shuai; Zhang, Hongti; Lu, Yang
2015-01-01
One-dimensional (1-D) nanomaterials exhibit great potentials in their applications to functional materials, nano-devices and systems owing to their excellent properties. In the past decade, considerable studies have been done, with new patents being developed, on these 1-D building blocks for for their mechanical properties, especially elastic properties, which provide a solid foundation for the design of nanoelectromechanical systems (NEMS) and predictions of reliability and longevity for their devices. This paper reviews some of the recent investigations on techniques as well as patents available for the quantitative characterization of the elastic behaviors of various 1-D nanomaterials, with particular focus on on-chip testing system. The review begins with an overview of major testing methods for 1-D nanostructures' elastic properties, including nanoindentation testing, AFM (atomic force microscopy) testing, in situ SEM (scanning electron microscopy) testing, in situ TEM (transmission electron microscopy) testing and the testing system on the basis of MEMS (micro-electro-mechanical systems) technology, followed by advantages and challenges of each testing approach. This review also focuses on the MEMS-based testing apparatus, which can be actuated and measured inside SEM and TEM with ease, allowing users to highly magnify the continuous images of the specimen while measuring load electronically and independently. The combination of on-chip technologies and the in situ electron microscopy is expected to be a potential testing technique for nanomechanics. Finally, details are presented on the key challenges and possible solutions in the implementation of the testing techniques referred above.
Finite Thin Cover on an Orthotropic Elastic Half Plane
Directory of Open Access Journals (Sweden)
Federico Oyedeji Falope
2016-01-01
Full Text Available The present work deals with the mechanical behaviour of thin films bonded to a homogeneous elastic orthotropic half plane under plain strain condition and infinitesimal strain. Both the film and semi-infinite substrate display linear elastic orthotropic behaviour. By assuming perfect adhesion between film and half plane together with membrane behaviour of the film, the compatibility condition between the coating and substrate leads to a singular integral equation with Cauchy kernel. Such an equation is straightforwardly solved by expanding the unknown interfacial stress in series of Chebyshev polynomials displaying square-root singularity at the film edges. This approach allows handling the singular behaviour of the shear stress and, in turn, reducing the problem to a linear algebraic system of infinite terms. Results are found for two loading cases, with particular reference to concentrated axial forces acting at the edges of the film. The corresponding mode II stress intensity factor has been assessed, thus providing the stress concentrations at both ends of the covering. Possible applications of the results here obtained range from MEMS, NEMS, and solar Silicon cell for energy harvesting to welded joint and building foundation.
Simple Explosive Plane Wave Booster Designs for 1-D Shock Experiments
Svingala, Forrest; Giannuzzi, Paul; Sandusky, Harold
2017-06-01
The gold standard 1-dimensional shock wave source is a flyer plate driven by a gas or powder gun. However, not all experimenters have access to such a gun, and some experiments that require large input areas (>80 cm2) and high input pressures (>15 GPa) are out of reach for most of those that do. An attractive alternative to gun-driven flyers in these cases is an explosive plane wave booster (PWB). The PWB uses an explosive train to produce a 1-D wave that can throw a flyer plate or be used directly. Shock pressure levels can be adjusted as needed through the use of attenuator plates or an explosive booster pad on the output of the PWB. Unfortunately, traditional ``dual velocity'' PWBs using two explosives require precision machining of the energetics, and as such can be difficult to produce and prohibitively expensive to purchase. This work explores several PWB designs that use cast explosives to keep costs down, and are easily scalable to the size of the required experiment. Their relative simultaneity and peak pressures are quantified using streak photography and photon Doppler velocimetry (PDV), and compared with typical values for the dual velocity lens and gun driven flyers.
Plane waves in a rotating generalized thermo-elastic solid with voids ...
African Journals Online (AJOL)
Propagation of plane waves in a rotating thermo-elastic solid with voids has been studied. The theory for thermo-elastic materials with voids developed by Iesan in the context of thermo- elastic theory of Lord and Shulman has been employed for mathematical treatment. It has been found that there exist one transverse wave ...
Reflection of plane waves from free surface of a microstretch elastic ...
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
In the present investigation, it is shown that there exists five basic waves in a microstretch elastic solid half-space. The problem of reflection of plane waves from free surface of a microstretch elastic solid half-space is studied. The energy ratios for various reflected waves are obtained for aluminium- epoxy composite as a ...
Influence of energy dissipation on plane harmonic waves through a piezo-thermo-elastic medium
Atwa, Sarhan Y.; Nazeer, M.; Adnan, J.; Rehman, Nadia
2017-07-01
The concept of thermo-elasticity proposed by Green and Naghdi is employed to study the plane harmonic waves through a piezo-electric thermo-elastic medium. An analytical technique of normal modes is adopted to find the exact solution of the problem. The theoretical results obtained are represented graphically for the particular material. It is found that energy dissipation reduces the amplitude of waves propagating through the medium. The results fully agree with physical interpretation of the problem.
Symmetric Problem of Elasticity Theory for a Half-Plane Weakened with a Round Opening and a Crack
Babloyan A.H.; Baghdasaryan A.V.
2007-01-01
The article presents the solution of a symmetric problem of elasticity theory for an elastic half-plane weakened by a round opening and a rectilinear crack, the latter being perpendicular to the edge of the half-plane. Symmetrically distributed normal loadings are given at the edges of the opening, the half-plane and banks of the split. On the infinity the half-plane spreads by equally distributed loadings with p intensity (fig.1).
A.H. Babloyan; A.V. Baghdasaryan
2007-01-01
The article presents the solution of a symmetric problem of elasticity theory for an elastic half-plane weakened by a round opening and a rectilinear internal crack, the latter being perpendicular to the edge of the half-plane. Symmetrically distributed normal loadings are given at the edges of the opening, the half-plane and banks of the split. On the infinity the half-plane spreads by equally distributed loadings with p intensity (fig.1).
Plane stress calculations with a two dimensional elastic-plastic computer program. [HEMP
Energy Technology Data Exchange (ETDEWEB)
Wilkins, M.L.; Guinan, M.W.
1976-04-05
In the study of ductile fracture it is useful to simulate fracture on the computer under plane stress conditions. In general, this is a three dimensional problem. Presented here is a method for adapting a two dimensional elastic-plastic computer program to calculate problems in plane stress as well as plane strain geometry. A simulation of a tension test of a flat aluminum plate pulled to failure is calculated with the modified two dimensional program. The results are compared with a fully three dimensional calculation. Finally a comparison is made with an experiment to demonstrate the effectiveness of the computational methods for studying fracture of work hardening materials.
Exact natural frequencies of plane structures composed of slender elastic curved members
Gupta, A. K.; Howson, W. P.
1994-08-01
Exact finite elements form the basis of a new and convenient procedure for converging with certainty upon the required natural frequencies of any plane structure composed of slender elastic curved members of constant radius. Solution of the inherent transcendental eigenvalue problem is achieved through a variation on the powerful Wittrick-Williams algorithm. Two illustrative examples are included.
Kim, Wansun; Lee, Inhwa; Kim, Dong Yoon; Yu, Youn-Yeol; Jung, Hae-Yoon; Kwon, Seyeoul; Park, Weon Seo; Kim, Taek-Soo
2017-05-01
To protect brittle layers in organic photovoltaic devices, the mechanical neutral plane strategy can be adopted through placing the brittle functional materials close to the neutral plane where stress and strain are zero during bending. However, previous research has been significantly limited in the location and number of materials to protect through using a single neutral plane. In this study, multiple neutral planes are generated using low elastic modulus adhesives and are controlled through quantitative analyses in order to protect the multiple brittle materials at various locations. Moreover, the protection of multiple brittle layers at various locations under both concave and convex bending directions is demonstrated. Multilayer structures that have soft adhesives are further analyzed using the finite element method analysis in order to propose guidelines for structural design when employing multiple neutral planes.
Elastic fields in two imperfectly bonded half-planes with a thermal inclusion of arbitrary shape
Wang, X.; Sudak, L. J.; Ru, C. Q.
2007-05-01
A general method is presented for the rigorous solution of Eshelby’s problem concerned with an arbitrary shaped inclusion embedded within one of two dissimilar elastic half-planes in plane elasticity. The bonding between the half-planes is considered to be imperfect with the assumption that the interface imperfections are uniform. Using analytic continuation, the basic boundary value problem is reduced to a set of two coupled nonhomogeneous first-order differential equations for two analytic functions defined in the lower half-plane which is free of the thermal inclusion. Using diagonalization, the two coupled differential equations are decoupled into two independent nonhomogeneous first-order differential equations for two newly defined analytic functions. The resulting closed-form solutions are given in terms of the constant imperfect interface parameters and the auxiliary function constructed from the conformal mapping which maps the exterior of the inclusion onto the exterior of the unit circle. The method is illustrated using several examples of an imperfect interface. In particular, when the same degree of imperfection is realized in both the normal and tangential directions between the two half-planes, a thermal inclusion of arbitrary shape in the upper half-plane does not cause any mean stress to develop in the lower half-plane. Alternatively, when the imperfect interface parameters are not equal, then a nonzero mean stress will be induced in the lower half-plane by the thermal inclusion of arbitrary shape in the upper half-plane. Detailed results are presented for the mean stress and the interfacial normal and shear stresses caused by a circular and elliptical thermal inclusion, respectively. Results from these calculations reveal that the imperfect bonding condition has a significant effect on the internal stress field induced within the inclusion as well as on the interfacial normal and shear stresses existing between the two half-planes especially
Laser-based linear and nonlinear guided elastic waves at surfaces (2D) and wedges (1D).
Hess, Peter; Lomonosov, Alexey M; Mayer, Andreas P
2014-01-01
The characteristic features and applications of linear and nonlinear guided elastic waves propagating along surfaces (2D) and wedges (1D) are discussed. Laser-based excitation, detection, or contact-free analysis of these guided waves with pump-probe methods are reviewed. Determination of material parameters by broadband surface acoustic waves (SAWs) and other applications in nondestructive evaluation (NDE) are considered. The realization of nonlinear SAWs in the form of solitary waves and as shock waves, used for the determination of the fracture strength, is described. The unique properties of dispersion-free wedge waves (WWs) propagating along homogeneous wedges and of dispersive wedge waves observed in the presence of wedge modifications such as tip truncation or coatings are outlined. Theoretical and experimental results on nonlinear wedge waves in isotropic and anisotropic solids are presented. Copyright © 2013 Elsevier B.V. All rights reserved.
Simplified description of out-of-plane waves in thin annular elastic plates
DEFF Research Database (Denmark)
Zadeh, Maziyar Nesari; Sorokin, Sergey
2013-01-01
Dispersion relations are derived for the out-of-plane wave propagation in planar elastic plates with constant curvature using the classical Kirchhoff thin plate theory. The dispersion diagrams and the mode shapes are compared with their counterparts for a straight plate strip and the role...... of curvature is assessed for plates with unconstrained edges. Elementary Bernoulli–Euler theory for a beam of rectangular cross-section with the circular shape of its axis is also employed to analyze the wave guide properties of this structure in its out-of-plane deformation. The applicability range...... of the elementary beam theory is validated. The wave finite element method in the formulation of the three-dimensional elasticity theory is used to ensure that the comparison of dispersion diagrams is performed in the frequency range, where the classical thin plate theory is valid. Thus, the paper summarizes...
Li, Shiguang; Oldenburg, Amy L.
2011-03-01
The detection of tumors in soft tissues, such as breast cancer, is important to achieve at the earliest stages of the disease to improve patient outcome. Tumors often exhibit a greater elastic modulus compared to normal tissues. In this paper, we report our first study to measure elastic properties of soft tissues by mapping the surface acoustic waves (SAWs) with image plane digital holography. The experimental results show that the SAW velocity is proportional to the square root of elastic modulus over a range from 3.7-122kPa in homogeneous tissue phantoms, consistent with Rayleigh wave theory. This technique also permits detection of the interface of two-layer phantoms 10mm deep under surface and the interface depth by quantifying the SAW dispersion.
Directory of Open Access Journals (Sweden)
Raphael Schween
Full Text Available Osteoarthritis of the knee affects millions of people. Elastic knee sleeves aim at relieving symptoms. While symptomatic improvements have been demonstrated as a consequence of elastic knee sleeves, evidence for biomechanical alterations only exists for the sagittal plane. We therefore asked what effect an elastic knee sleeve would have on frontal plane gait biomechanics.18 subjects (8 women, 10 men with osteoarthritis of the medial tibiofemoral joint walked over ground with and without an elastic knee sleeve. Kinematics and forces were recorded and joint moments were calculated using an inverse dynamics approach. Conditions with sleeve and without sleeve were compared with paired t-Tests.With the sleeve, knee adduction angle at ground contact was reduced by 1.9 ± 2.1° (P = 0.006. Peak knee adduction was reduced by 1.5 ± 1.6° (P = 0.004. The first peak knee adduction moment and positive knee adduction impulse were decreased by 10.1% (0.74 ± 0.9 Nm • kg-1; P = 0.002 and 12.9% (0.28 ± 0.3 Nm • s • kg-1; P < 0.004, respectively.Our study provides evidence that wearing an elastic knee sleeve during walking can reduce knee adduction angles, moments and impulse in subjects with knee osteoarthritis. As a higher knee adduction moment has previously been identified as a risk factor for disease progression in patients with medial knee osteoarthritis, we speculate that wearing a knee sleeve may be beneficial for this specific subgroup.
Fu-yao Zhao; Er-xiang Song; Jun Yang
2015-01-01
The rotary vibration of rigid friction pile can be seen approximately as a central symmetry plane problem in elasticity. The stress general solution of central symmetry plane problem in elasticity can be constructed by technique such as the Laurent expansion of the volume force. This solution has some decoupling, generalized, and convergent properties, and it can be used in stress analysis of the rotary vibration of pile. The analysis results show that the maximum value of displacement will n...
Standard test method for linear-elastic plane-strain fracture toughness KIc of metallic materials
American Society for Testing and Materials. Philadelphia
2013-01-01
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...
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...
In-Plane free Vibration Analysis of an Annular Disk with Point Elastic Support
Directory of Open Access Journals (Sweden)
S. Bashmal
2011-01-01
Full Text Available In-plane free vibrations of an elastic and isotropic annular disk with elastic constraints at the inner and outer boundaries, which are applied either along the entire periphery of the disk or at a point are investigated. The boundary characteristic orthogonal polynomials are employed in the Rayleigh-Ritz method to obtain the frequency parameters and the associated mode shapes. Boundary characteristic orthogonal polynomials are generated for the free boundary conditions of the disk while artificial springs are used to account for different boundary conditions. The frequency parameters for different boundary conditions of the outer edge are evaluated and compared with those available in the published studies and computed from a finite element model. The computed mode shapes are presented for a disk clamped at the inner edge and point supported at the outer edge to illustrate the free in-plane vibration behavior of the disk. Results show that addition of point clamped support causes some of the higher modes to split into two different frequencies with different mode shapes.
Lin, Chien-Han; Wang, Chien-Kai; Chen, Yu-An; Peng, Chien-Chung; Liao, Wei-Hao; Tung, Yi-Chung
2016-01-01
In various physiological activities, cells experience stresses along their in-plane direction when facing substrate deformation. Capability of continuous monitoring elasticity of live cell layers during a period is highly desired to investigate cell property variation during various transformations under normal or disease states. This paper reports time-lapsed measurement of live cell layer in-plane elasticity using a pressure sensor embedded microfluidic device. The sensor converts pressure-induced deformation of a flexible membrane to electrical signals. When cells are cultured on top of the membrane, flexural rigidity of the composite membrane increases and further changes the output electrical signals. In the experiments, human embryonic lung fibroblast (MRC-5) cells are cultured and analyzed to estimate the in-plane elasticity. In addition, the cells are treated with a growth factor to simulate lung fibrosis to study the effects of cell transformation on the elasticity variation. For comparison, elasticity measurement on the cells by atomic force microscopy (AFM) is also performed. The experimental results confirm highly anisotropic configuration and material properties of cells. Furthermore, the in-plane elasticity can be monitored during the cell transformation after the growth factor stimulation. Consequently, the developed microfluidic device provides a powerful tool to study physical properties of cells for fundamental biophysics and biomedical researches. PMID:27812019
National Research Council Canada - National Science Library
Liu Weidong Zhu Hua Zhou Shengqiang Bai Yalei Wang Yuan Zhao Chunsheng
2013-01-01
...） and experiments have been performed to validate the theoretical model. The in-plane characteristics of the cosine honeycomb are compared with accordion honeycomb through analytical models and experiments...
Directory of Open Access Journals (Sweden)
Chris L. de Korte
2013-03-01
Full Text Available Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding.
Hansen, Hendrik H.G.; Richards, Michael S.; Doyley, Marvin M.; de Korte, Chris L.
2013-01-01
Atherosclerotic plaque rupture can initiate stroke or myocardial infarction. Lipid-rich plaques with thin fibrous caps have a higher risk to rupture than fibrotic plaques. Elastic moduli differ for lipid-rich and fibrous tissue and can be reconstructed using tissue displacements estimated from intravascular ultrasound radiofrequency (RF) data acquisitions. This study investigated if modulus reconstruction is possible for noninvasive RF acquisitions of vessels in transverse imaging planes using an iterative 2D cross-correlation based displacement estimation algorithm. Furthermore, since it is known that displacements can be improved by compounding of displacements estimated at various beam steering angles, we compared the performance of the modulus reconstruction with and without compounding. For the comparison, simulated and experimental RF data were generated of various vessel-mimicking phantoms. Reconstruction errors were less than 10%, which seems adequate for distinguishing lipid-rich from fibrous tissue. Compounding outperformed single-angle reconstruction: the interquartile range of the reconstructed moduli for the various homogeneous phantom layers was approximately two times smaller. Additionally, the estimated lateral displacements were a factor of 2–3 better matched to the displacements corresponding to the reconstructed modulus distribution. Thus, noninvasive elastic modulus reconstruction is possible for transverse vessel cross sections using this cross-correlation method and is more accurate with compounding. PMID:23478602
Guo, Lei; Nie, Guohua
2008-02-01
This paper presents an analytical solution for the elastic fields induced by non-elastic eigenstrains in a plane elliptical inhomogeneity embedded in the orthotropic matrix under tension at infinity and inclined at any angle. The conformal transformation and complex function method for the anisotropic elastic material were used to determine the strain energies in the inhomogeneity and matrix, which were expressed by four undetermined coefficients characterizing the equilibrium boundary of the inhomogeneity due to the acting eigenstrains and external load. The use of the principle of the minimum potential energy led to analytical expressions for these coefficients and thus generated a closed-form solution for the elastic strain/stress fields. The resulting stress field in the inhomogeneity was examined and verified by checking the continuity conditions for the normal and shear stresses on the interior boundary of the matrix.
Directory of Open Access Journals (Sweden)
E. BOSCHI
1974-06-01
Full Text Available This paper is concerned with the plane strain in a theory for an arbitrary, uniformly rotating, self-gravitating, perfectly elastic Earth model with a hydrostatic initial stress field. Using the associated matrices method, a representation of Galerkin type is given. This representation enables us to derive the solution of the vibration problem corresponding to concentrated body forces.
DEFF Research Database (Denmark)
Andriollo, Tito; Thorborg, Jesper; Hattel, Jesper Henri
2016-01-01
In the present paper, for the first time in literature an exact analytical solution to Lemaitre's isotropic damage model is developed for the special case of uniaxial tensile testing. This is achieved by taking advantage of a convenient formulation of the isotropic hardening function, which allows...... obtaining an integral relationship between total strain and effective stress. By means of the generalized binomial theorem, an expression in terms of infinite series is subsequently derived. The solution is found to simplify considerably existing techniques for material parameters identification based...... on optimization, as all issues associated with classical numerical solution procedures of the constitutive equations are eliminated. In addition, an implicit implementation of the plane stress projected version of Lemaitre's model is discussed, showing that the resulting algebraic system can be reduced...
Plasmonic Bandgaps in 1D Arrays of Slits on Metal Layers Excited by Out-of-Plane Sources
Directory of Open Access Journals (Sweden)
Roberto Marani
2012-01-01
Full Text Available We analyze the effective opening of finite bands of inhibited transmission in realistic systems excited by actual out-of-plane sources. We first observe how the excitation of surface plasmon polaritons in one-dimensional arrays of metal slits depends on the angle of incidence of the source field. Then, the well-known grating-coupling equation is revised in order to find an asymmetric structure with equivalent parameters which, under perfectly normal excitation, is able to exhibit surface plasmon polariton modes at the same wavelengths of the original structure which undergoes a nonorthogonal incidence of the light. In this way we demonstrate through finite-element simulations that a realistic system, probed by a source beam in a finite light-cone, can be effectively decomposed in several equivalent systems with different physical and geometrical parameters, with results in the enlargement of the theoretically expected punctual minimum of transmission.
Directory of Open Access Journals (Sweden)
Hanson Huang
1996-01-01
Full Text Available A detailed solution to the transient interaction of plane acoustic waves with a spherical elastic shell was obtained more than a quarter of a century ago based on the classical separation of variables, series expansion, and Laplace transform techniques. An eight-term summation of the time history series was sufficient for the convergence of the shell deflection and strain, and to a lesser degree, the shell velocity. Since then, the results have been used routinely for validation of solution techniques and computer methods for the evaluation of underwater explosion response of submerged structures. By utilizing modern algorithms and exploiting recent advances of computer capacities and floating point mathematics, sufficient terms of the inverse Laplace transform series solution can now be accurately computed. Together with the application of the Cesaro summation using up to 70 terms of the series, two primary deficiencies of the previous solution are now remedied: meaningful time histories of higher time derivative data such as acceleration and pressure are now generated using a sufficient number of terms in the series; and uniform convergence around the discontinuous step wave front is now obtained, completely eradicating spurious oscillations due to the Gibbs' phenomenon. New results of time histories of response items of interest are presented.
Hasheminejad, Seyyed M.; Ghaheri, Ali; Rezaei, Shahed
2012-01-01
A two-dimensional analytical model is developed to describe the free extensional vibrations of thin elastic plates of elliptical planform with or without a confocal cutout under general elastically restrained edge conditions, based on the Navier displacement equation of motion for a state of plane stress. The model has been simplified by invoking the Helmholtz decomposition theorem, and the method of separation of variables in elliptic coordinates is used to solve the resulting uncoupled governing equations in terms of products of (even and odd) angular and radial Mathieu functions. Extensive numerical results are presented in an orderly fashion for the first three anti-symmetric/symmetric natural frequencies of elliptical plates of selected geometries under different combinations of classical (clamped and free) and flexible boundary conditions. Also, the occurrences of "frequency veering" between various modes of the same symmetry group and interchange of the associated mode shapes in the veering region are noted and discussed. Moreover, selected 2D deformed mode shapes are presented in vivid graphical form. The accuracy of solutions is checked through appropriate convergence studies, and the validity of results is established with the aid of a commercial finite element package as well as by comparison with the data in the existing literature. The set of data reported herein is believed to be the first rigorous attempt to obtain the in-plane vibration frequencies of solid and annular thin elastic elliptical plates for a wide range of plate eccentricities.
An IBEM solution to the scattering of plane SH-waves by a lined tunnel in elastic wedge space
Liu, Zhongxian; Liu, Lei
2015-02-01
The indirect boundary element method (IBEM) is developed to solve the scattering of plane SH-waves by a lined tunnel in elastic wedge space. According to the theory of single-layer potential, the scattered-wave field can be constructed by applying virtual uniform loads on the surface of lined tunnel and the nearby wedge surface. The densities of virtual loads can be solved by establishing equations through the continuity conditions on the interface and zero-traction conditions on free surfaces. The total wave field is obtained by the superposition of free field and scattered-wave field in elastic wedge space. Numerical results indicate that the IBEM can solve the diffraction of elastic wave in elastic wedge space accurately and efficiently. The wave motion feature strongly depends on the wedge angle, the angle of incidence, incident frequency, the location of lined tunnel, and material parameters. The waves interference and amplification effect around the tunnel in wedge space is more significant, causing the dynamic stress concentration factor on rigid tunnel and the displacement amplitude of flexible tunnel up to 50.0 and 17.0, respectively, more than double that of the case of half-space. Hence, considerable attention should be paid to seismic resistant or anti-explosion design of the tunnel built on a slope or hillside.
Graba, M.
2017-02-01
This paper provides a numerical analysis of selected parameters of fracture mechanics for double-edge notched specimens in tension, DEN(T), under plane strain conditions. The analysis was performed using the elastic-plastic material model. The study involved determining the stress distribution near the crack tip for both small and large deformations. The limit load solution was verified. The J-integral, the crack tip opening displacement, and the load line displacement were determined using the numerical method to propose the new hybrid solutions for calculating these parameters. The investigations also aimed to identify the influence of the plate geometry and the material characteristics on the parameters under consideration. This paper is a continuation of the author's previous studies and simulations in the field of elastic-plastic fracture mechanics.
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.
Possible second-order nonlinear interactions of plane waves in an elastic solid
Korneev, V.A.; Demcenko, A.
2014-01-01
There exist ten possible nonlinear elastic wave interactions for an isotropic solid described by three constants of the third order. All other possible interactions out of 54 combinations (triplets) of interacting and resulting waves are prohibited, because of restrictions of various kinds. The
Directory of Open Access Journals (Sweden)
Fu-yao Zhao
2015-01-01
Full Text Available The rotary vibration of rigid friction pile can be seen approximately as a central symmetry plane problem in elasticity. The stress general solution of central symmetry plane problem in elasticity can be constructed by technique such as the Laurent expansion of the volume force. This solution has some decoupling, generalized, and convergent properties, and it can be used in stress analysis of the rotary vibration of pile. The analysis results show that the maximum value of displacement will not occur at the edge of the pile and the assumption that pile cross section remains unchanged is no longer applicable, if the value of one dimensionless quantity, reflecting the angular frequency of the rotation, radius, and material properties of the pile, is larger than 1.84. Once the rotary vibration of rigid friction pile happens, the pile may lose its bearing capacity under the comprehensive effect of normal and shear stress of the pile-soil interface and it will be very difficult to recover.
Semi-analytical solution to plane strain loading of elastic layered ...
Indian Academy of Sciences (India)
coating system is simulated through three different pressure profiles for a fixed total load and loading zone ... jected to plane strain normal and sliding contact combining the approaches of Chen & Engel. (1972) and Gupta and ... of the present work and utilizes Airy stress function approach, Fourier cosine transform to solve.
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.
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Jeom Kee Paik
2012-01-01
Full Text Available The Galerkin method is applied to analyze the elastic large deflection behavior of metal plates subject to a combination of in-plane loads such as biaxial loads, edge shear and biaxial inplane bending moments, and uniformly or nonuniformly distributed lateral pressure loads. The motive of the present study was initiated by the fact that metal plates of ships and ship-shaped offshore structures at sea are often subjected to non-uniformly distributed lateral pressure loads arising from cargo or water pressure, together with inplane axial loads or inplane bending moments, but the current practice of the maritime industry usually applies some simplified design methods assuming that the non-uniform pressure distribution in the plates can be replaced by an equivalence of uniform pressure distribution. Applied examples are presented, demonstrating that the current plate design methods of the maritime industry may be inappropriate when the non-uniformity of lateral pressure loads becomes more significant.
Kashchenko, M. P.; Chashchina, V. G.
2017-11-01
The possibility of inheritance of the elastic field in the zone of appearance of the initial excited state by the wave process controlling growth of the martensite crystal is shown. The case when the wave vectors of the control waves belong to plane {110}c of the original cubic phase is analyzed. Implementability of such inheritance is demonstrated with the use of elastic moduli for single-crystal bcc titanium, which advances the predictive capacity of the dynamic theory.
Directory of Open Access Journals (Sweden)
Fabian Lamus
2011-01-01
Full Text Available This work describes a numerical model of fibre reinforced concrete elastic behaviour implemented using the finite elements method (Hughes, 2000. In structures made of this material, each point is formed by steel fibres embedded into a simple concrete matrix. The reinforced concrete is represented inside a finite element as an orthotropic material having random material direction based on the vanishing diameter fibre model (Dvorak and Bahei-el-Din, 1982 and the mixing theory modified for short length reinforcement (Oller, 2003. Statistical analysis consisted of repeating the problem’s numerical simulation where the direction of fibres was modified by a random function to set up a sampling database from the results and measure their variability. A sensitivity study of finite element size and the number of sampling data was then carried out in terms of total strain energy. Finite element size and sampling data are recommended. The average structural response of a reinforced concrete beam with different quantities of steel fibres where minimum data dispersion was observed is given as an example of applying the above.
Brandow, Heather P.; Lee, Vincent
2017-07-01
Scattering and Diffraction of elastic in-plane P- and SV- waves by a surface topography such as an elastic canyon at the surface of a half-space is a classical problem which has been studied by earthquake engineers and strong-motion seismologists for over forty years. The case of out-of-plane SH waves on the same elastic canyon that is semi-circular in shape on the half-space surface is the first such problem that was solved by analytic closed form solutions over forty years ago by Trifunac. The corresponding case of in-plane P- and SV-waves on the same circular canyon is a much more complicated problem because, the in-plane P- and SV- scattered waves have different wave speeds and together they must have zero normal and shear stresses at the half-space surface. It is not until recently in 2014 that analytic solution for such problem is found by the author in the work of Lee and Liu. This paper uses the technique of Lee and Liu of defining these stress-free scattered waves to solve the problem of the scattered and diffraction of these in-plane waves on an almost-circular surface canyon that is arbitrary in shape.
Liu, Zhongxian; Wang, Yirui; Liang, Jianwen
2016-06-01
The scattering of plane harmonic P and SV waves by a pair of vertically overlapping lined tunnels buried in an elastic half space is solved using a semi-analytic indirect boundary integration equation method. Then the effect of the distance between the two tunnels, the stiffness and density of the lining material, and the incident frequency on the seismic response of the tunnels is investigated. Numerical results demonstrate that the dynamic interaction between the twin tunnels cannot be ignored and the lower tunnel has a significant shielding effect on the upper tunnel for high-frequency incident waves, resulting in great decrease of the dynamic hoop stress in the upper tunnel; for the low-frequency incident waves, in contrast, the lower tunnel can lead to amplification effect on the upper tunnel. It also reveals that the frequency-spectrum characteristics of dynamic stress of the lower tunnel are significantly different from those of the upper tunnel. In addition, for incident P waves in low-frequency region, the soft lining tunnels have significant amplification effect on the surface displacement amplitude, which is slightly larger than that of the corresponding single tunnel.
Directory of Open Access Journals (Sweden)
Nahed S. Hussein
2014-01-01
Full Text Available A numerical boundary integral scheme is proposed for the solution to the system of eld equations of plane. The stresses are prescribed on one-half of the circle, while the displacements are given. The considered problem with mixed boundary conditions in the circle is replaced by two problems with homogeneous boundary conditions, one of each type, having a common solution. The equations are reduced to a system of boundary integral equations, which is then discretized in the usual way, and the problem at this stage is reduced to the solution to a rectangular linear system of algebraic equations. The unknowns in this system of equations are the boundary values of four harmonic functions which define the full elastic solution and the unknown boundary values of stresses or displacements on proper parts of the boundary. On the basis of the obtained results, it is inferred that a stress component has a singularity at each of the two separation points, thought to be of logarithmic type. The results are discussed and boundary plots are given. We have also calculated the unknown functions in the bulk directly from the given boundary conditions using the boundary collocation method. The obtained results in the bulk are discussed and three-dimensional plots are given. A tentative form for the singular solution is proposed and the corresponding singular stresses and displacements are plotted in the bulk. The form of the singular tangential stress is seen to be compatible with the boundary values obtained earlier. The efficiency of the used numerical schemes is discussed.
Energy Technology Data Exchange (ETDEWEB)
Cannelli, G. (Universita di Perugia, Dipartimento di Fisica, I-06100 Perugia (Italy)); Cantelli, R. (II Universita di Roma, Dipartimento di Fisica, Via E. Carnevale, I-00173 Roma (Italy)); Cordero, F. (Consiglio Nazionale delle Richerche, Istituto di Acustica O. M. Corbino,' ' via Cassia 1216, I-00189 Roma (Italy)); Ferretti, M. (Universita di Genova, Istituto di Chimica Fisica, I-16132 Genova (Italy)); Verdini, L. (Universita di Perugia, Dipartimento di Fisica, I-06100 Perugia (Italy))
1990-11-01
We report elastic-energy-dissipation measurements in YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} from 50 to 300 K at frequencies between 0.48 and 6.3 kHz. It is shown unambiguously that the two peaks around {Tc} are thermally activated with activation energies of 0.16 and 0.19 eV. When oxygen is reduced to about 6.5 atoms per formula unit, the higher-temperature process nearly disappears, while the other one increases. The peaks are interpreted in terms of jumps of the O atoms in the Cu-O basal planes, and two mechanisms are proposed and discussed: short jumps between the off-center positions in the chains and jumps between O(4) and O(5) positions of isolated atoms in hypothetical oxygen-depleted islands of the orthorhombic basal planes.
Directory of Open Access Journals (Sweden)
Rajneesh Kumar
Full Text Available The problem of reflection and refraction phenomenon due to plane waves incident obliquely at a plane interface between uniform elastic solid half-space and microstretch thermoelastic diffusion solid half-space has been studied. It is found that the amplitude ratios of various reflected and refracted waves are functions of angle of incidence, frequency of incident wave and are influenced by the microstretch thermoelastic diffusion properties of the media. The expressions of amplitude ratios and energy ratios are obtained in closed form. The energy ratios have been computed numerically for a particular model. The variations of energy ratios with angle of incidence are shown for thermoelastic diffusion media in the context of Lord-Shulman (L-S (1967 and Green-Lindsay (G-L (1972 theories. The conservation of energy at the interface is verified. Some particular cases are also deduced from the present investigation.
Zhang, Jiawei; Zhang, Jie; Zhao, Yongli; Yang, Hui; Yu, Xiaosong; Wang, Lei; Fu, Xihua
2013-01-28
Due to the prominent performance on networking virtualization and programmability, OpenFlow is widely regarded as a promising control plane technology in packet-switched IP networks as well as wavelength-switched optical networks. For the purpose of applying software programmable feature to future optical networks, we propose an OpenFlow-based control plane in Flexi-Grid optical networks. Experimental results demonstrate its feasibility of dynamic lightpath establishment and adjustment via extended OpenFlow protocol. Wireshark captures of the signaling procedure are printed out. Additionally, the overall latency including signaling and hardware for lightpath setup and adjustment is also reported.
Directory of Open Access Journals (Sweden)
Giovanni Cimatti
2014-05-01
Full Text Available We propose a new weak formulation for the plane problem of thermoelastic theory in multiply-connected domains. This permits to avoid the difficulties connected with the Cesaro-Volterra boundary conditions in the related elliptic boundary-value problem. In the second part we consider a nonlinear version of the problem assuming that the thermal conductivity depends not only on the temperature but also on the pressure. Recent studies reveals that this situation can occur in practice. A theorem of existence and uniqueness is proved for this problem.
Directory of Open Access Journals (Sweden)
Américo G Hossne
2010-12-01
Full Text Available A lineal finite element with constant traverse section, it can adopt any orientation in the plane, and their ends or nodes tie it to the rest of the elements. The kinetic energy (T and potential (V of a dynamic elastic element are the basement in the implementation of the Hamilton principle for the definition of a finite element. The definition of the kinetic energy and potential is the first step for the preliminary variational formulation to the enunciation for finite elements that it is used to solve, say, the problems of mechanisms that move in the plane using the Hamilton equation. The general objective consisted on defining the equation of the movement of a finite lineal dynamic elastic plane element using the equation of Hamilton, starting from the lagrangiana (T − V obtained with the use of a polynomial of fifth and first degree, with eight degrees of freedom, four in each node that represented the deformations: axial (u(x, traverse (w(x, slope ((dw(x/dx and bend ((d2w(x/dx2. The deformation due to traverse shearing, insignificant with respect to flexional and axial deformations, the rotational inertia and the frictional forces in the nodes, were underrated with the purpose of producing a friendly element. The specific objectives were to take place: (a the translational mass matrix [MD], (b the translational gyroscopic matrix [AD], (c the translational total rigidity matrix [KD], and (d the deformation vector (S. As a result the movement equation of a finite lineal dynamic elastic plane element was forged [MD]( ¨ S − 2¨[AD]( ˙S + {[K] − ˙2[MD] − ¨[AD]}(S = (Q . On concluded that the equation obtained variationally with the application of the Hamilton Principle is the state–of–the–art pattern, and that the procedure can be used when it is required to increase the number of the pattern freedom degrees.Un elemento finito lineal con sección transversal constante puede adoptar cualquier orientación en el plano y sus
Liu, Lei; Peng, Wei-Ren; Casellas, Ramon; Tsuritani, Takehiro; Morita, Itsuro; Martínez, Ricardo; Muñoz, Raül; Yoo, S J B
2014-01-13
Optical Orthogonal Frequency Division Multiplexing (O-OFDM), which transmits high speed optical signals using multiple spectrally overlapped lower-speed subcarriers, is a promising candidate for supporting future elastic optical networks. In contrast to previous works which focus on Coherent Optical OFDM (CO-OFDM), in this paper, we consider the direct-detection optical OFDM (DDO-OFDM) as the transport technique, which leads to simpler hardware and software realizations, potentially offering a low-cost solution for elastic optical networks, especially in metro networks, and short or medium distance core networks. Based on this network scenario, we design and deploy a software-defined networking (SDN) control plane enabled by extending OpenFlow, detailing the network architecture, the routing and spectrum assignment algorithm, OpenFlow protocol extensions and the experimental validation. To the best of our knowledge, it is the first time that an OpenFlow-based control plane is reported and its performance is quantitatively measured in an elastic optical network with DDO-OFDM transmission.
Directory of Open Access Journals (Sweden)
Yu Jing
2015-08-01
Full Text Available Based on the fundamental equations of piezoelasticity of quasicrystal media, using the symmetry operations of point groups, the linear piezoelasticity behavior of one-dimensional (1D hexagonal quasicrystals is investigated and the piezoelasticity problem of 1D hexagonal quasicrystals is decomposed into two uncoupled problems, i.e., the classical plane elasticity problem of conventional hexagonal crystals and the phonon–phason-electric coupling elasticity problem of 1D hexagonal quasicrystals. The final governing equations are derived for the phonon–phason-electric coupling anti-plane elasticity of 1D hexagonal quasicrystals. The complex variable method for an anti-plane elliptical cavity in 1D hexagonal piezoelectric quasicrystals is proposed and the exact solutions of complex potential functions, the stresses and displacements of the phonon and the phason fields, the electric displacements and the electric potential are obtained explicitly. Reducing the cavity into a crack, the explicit solutions in closed forms of electro–elastic fields, the field intensity factors and the energy release rate near the crack tip are derived.
Sekiguchi, K; Sakai, H; Witala, H; Ermisch, K; Glockle, W; Golak, J; Hatano, M; Kamada, H; Kalantar-Nayestanaki, N; Kato, H; Maeda, Y; Nishikawa, J; Nogga, A; Ohnishi, T; Okamura, H; Saito, T; Sakamoto, N; Sakoda, S; Satou, Y; Suda, K; Tamii, A; Uchigashima, T; Uesaka, T; Wakasa, T; Yako, K
The deuteron-to-proton polarization-transfer coefficients for d-p elastic scattering were precisely measured with an incoming deuteron energy of 135 MeV/nucleon at the RIKEN Accelerator Research Facility. The data are compared to theoretical predictions based on exact solution's of the three-nucleon
Deng, Xiaomin; Rosakis, Ares J.
1992-11-01
Quasi-static and dynamic crack growth under mode I plane stress, steady state, and small-scale yielding conditions was investigated for power-law hardening elastic-plastic materials which are homogenous and isotropic and obey the von Mises yield criterion and the associated flow rule. The effective stress-strain curve of the materials is assumed to follow the Ramberg-Osgood-type power law effective stress-strain curve. The results show many similarities with those found by Deng and Rosakis (1992) for linear hardening solids, except that, in case of power-law hardening materials, the plastic strain singularities at the crack tip are of logarithmic type.
Vassiliev, Dmitri
2017-04-01
We consider an infinite three-dimensional elastic continuum whose material points experience no displacements, only rotations. This framework is a special case of the Cosserat theory of elasticity. Rotations of material points are described mathematically by attaching to each geometric point an orthonormal basis that gives a field of orthonormal bases called the coframe. As the dynamical variables (unknowns) of our theory, we choose the coframe and a density. We write down the general dynamic variational functional for our rotational theory of elasticity, assuming our material to be physically linear but the kinematic model geometrically nonlinear. Allowing geometric nonlinearity is natural when dealing with rotations because rotations in dimension three are inherently nonlinear (rotations about different axes do not commute) and because there is no reason to exclude from our study large rotations such as full turns. The main result of the talk is an explicit construction of a class of time-dependent solutions that we call plane wave solutions; these are travelling waves of rotations. The existence of such explicit closed-form solutions is a non-trivial fact given that our system of Euler-Lagrange equations is highly nonlinear. We also consider a special case of our rotational theory of elasticity which in the stationary setting (harmonic time dependence and arbitrary dependence on spatial coordinates) turns out to be equivalent to a pair of massless Dirac equations. The talk is based on the paper [1]. [1] C.G.Boehmer, R.J.Downes and D.Vassiliev, Rotational elasticity, Quarterly Journal of Mechanics and Applied Mathematics, 2011, vol. 64, p. 415-439. The paper is a heavily revised version of preprint https://arxiv.org/abs/1008.3833
Nonlinear elastic waves in materials
Rushchitsky, Jeremiah J
2014-01-01
The main goal of the book is a coherent treatment of the theory of propagation in materials of nonlinearly elastic waves of displacements, which corresponds to one modern line of development of the nonlinear theory of elastic waves. The book is divided on five basic parts: the necessary information on waves and materials; the necessary information on nonlinear theory of elasticity and elastic materials; analysis of one-dimensional nonlinear elastic waves of displacement – longitudinal, vertically and horizontally polarized transverse plane nonlinear elastic waves of displacement; analysis of one-dimensional nonlinear elastic waves of displacement – cylindrical and torsional nonlinear elastic waves of displacement; analysis of two-dimensional nonlinear elastic waves of displacement – Rayleigh and Love nonlinear elastic surface waves. The book is addressed first of all to people working in solid mechanics – from the students at an advanced undergraduate and graduate level to the scientists, professional...
Hwu, Chyanbin
2010-01-01
As structural elements, anisotropic elastic plates find wide applications in modern technology. The plates here are considered to be subjected to not only in plane load but also transverse load. In other words, both plane and plate bending problems as well as the stretching-bending coupling problems are all explained in this book. In addition to the introduction of the theory of anisotropic elasticity, several important subjects have are discussed in this book such as interfaces, cracks, holes, inclusions, contact problems, piezoelectric materials, thermoelastic problems and boundary element a
Complex variable methods in elasticity
England, A H
2003-01-01
The plane strain and generalized plane stress boundary value problems of linear elasticity are the focus of this graduate-level text, which formulates and solves these problems by employing complex variable theory. The text presents detailed descriptions of the three basic methods that rely on series representation, Cauchy integral representation, and the solution via continuation. Its five-part treatment covers functions of a complex variable, the basic equations of two-dimensional elasticity, plane and half-plane problems, regions with circular boundaries, and regions with curvilinear bounda
Analytical solutions of plane elasticity problems Part I: Elastic ...
African Journals Online (AJOL)
Cette méthode a donc été appliquée à la détermination des expressions analytiques (en conservant sous leur forme symbolique tous les paramètres liés à la géométrie et au chargement) des champs de contraintes et de déplacements dans une plaque élastique sous diverses sollicitations et comportant un trou elliptique.
Directory of Open Access Journals (Sweden)
Helbig K.
2006-12-01
Full Text Available Planes of symmetry are often identified by the existence of pure cross-plane polarization. However, this type of polarization can occur without the plane being a plane of symmetry. Planes that support cross-plane polarization are called decoupling planes , since the system of three coupled linear equations in the direction cosines of the polarization vector decouples into a single cross-plane equation and a coupled pair of in-plane equations. Only if the direction perpendicular to a decoupling plane is a longitudinal direction(i. e. , if in the direction there are pure P- and S-waves, it is a plane of symmetry. Without the observation of the associated longitudinal direction, a rawdecoupling plane might be mis-interpreted as a plane of symmetry. The plane perpendicular to the i-direction is a decoupling plane if in four-subscript notation all stiffnesses with a single subscript i vanish; the i-direction is a longitudinal di-rection if all stiffnesses with three subscripts i vanish. In media of orthorhombic or higher symmetry all stiffnesses with any single or triple subscript vanish; therefore raw decoupling planes can occur only in media of monoclinic or triclinic symmetry. In triclinic symmetry, two mutually perpendicular raw decoupling planes can occur. Decoupling planes intersecting under an oblique angle are possible if the stiffnesses satisfy a number of constraints. Les plans de symétrie sont souvent identifiés par l'existence d'une polarisation pure perpendiculaire à ces plans. Cependant, ce type de polarisation peut apparaître sans que le plan soit un plan de symétrie. Les plans qui présentent une polarisation pure suivant leurs normales sont appelés plans de découplage , car le système de trois équations linéaires couplées par les cosinus directeurs du vecteur de polarisation se découple en une seule équation relative à la polarisation normale au plan et en deux équations couplées relatives aux polarisations dans le
Hall, Timothy J; Oberait, Assad A; Barbone, Paul E; Sommer, Amy M; Gokhale, Nachiket H; Goenezent, Sevan; Jiang, Jingfeng
2009-01-01
Previous work has demonstrated improved diagnostic performance of highly trained breast radiologists when provided with B-mode plus elastography images over B-mode images alone. In those studies we have observed that elasticity imaging can be difficult to perform if there is substantial motion of tissue out of the image plane. So we are extending our methods to 3D/4D elasticity imaging with 2D arrays. Further, we have also documented the fact that some breast tumors change contrast with increasing deformation and those observations are consistent with in vitro tissue measurements. Hence, we are investigating imaging tissue stress-strain nonlinearity. These studies will require relatively large tissue deformations (e.g., > 20%) which will induce out of plane motion further justifying 3D/4D motion tracking. To further enhance our efforts, we have begun testing the ability to perform modulus reconstructions (absolute elastic parameter) imaging of in vivo breast tissues. The reconstructions are based on high quality 2D displacement estimates from strain imaging. Piecewise linear (secant) modulus reconstructions demonstrate the changes in elasticity image contrast seen in strain images but, unlike the strain images, the contrast in the modulus images approximates the absolute modulus contrast. Nonlinear reconstructions assume a reasonable approximation to the underlying constitutive relations for the tissue and provide images of the (near) zero-strain shear modulus and a nonlinearity parameter that describes the rate of tissue stiffening with increased deformation. Limited data from clinical trials are consistent with in vitro measurements of elastic properties of tissue samples and suggest that the nonlinearity of invasive ductal carcinoma exceeds that of fibroadenoma and might be useful for improving diagnostic specificity. This work is being extended to 3D.
Beame, Paul; Fleming, Noah; Impagliazzo, Russell; Kolokolova, Antonina; Pankratov, Denis; Pitassi, Toniann; Robere, Robert
2017-01-01
We introduce and develop a new semi-algebraic proof system, called Stabbing Planes that is in the style of DPLL-based modern SAT solvers. As with DPLL, there is only one rule: the current polytope can be subdivided by branching on an inequality and its "integer negation." That is, we can (nondeterministically choose) a hyperplane a x \\geq b with integer coefficients, which partitions the polytope into three pieces: the points in the polytope satisfying a x \\geq b, the points satisfying a x \\l...
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
Three-dimensional Ultrasound Elasticity Imaging on an Automated Breast Volume Scanning System.
Wang, Yuqi; Nasief, Haidy G; Kohn, Sarah; Milkowski, Andy; Clary, Tom; Barnes, Stephen; Barbone, Paul E; Hall, Timothy J
2017-11-01
Ultrasound elasticity imaging has demonstrated utility in breast imaging, but it is typically performed with handheld transducers and two-dimensional imaging. Two-dimensional (2D) elastography images tissue stiffness of only a plane and hence suffers from errors due to out-of-plane motion, whereas three-dimensional (3D) data acquisition and motion tracking can be used to track out-of-plane motion that is lost in 2D elastography systems. A commercially available automated breast volume scanning system that acquires 3D ultrasound data with precisely controlled elevational movement of the 1D array ultrasound transducer was employed in this study. A hybrid guided 3D motion-tracking algorithm was developed that first estimated the displacements in one plane using a modified quality-guided search method, and then performed an elevational guided-search for displacement estimation in adjacent planes. To assess the performance of the method, 3D radiofrequency echo data were acquired with this system from a phantom and from an in vivo human breast. For both experiments, the axial displacement fields were smooth and high cross-correlation coefficients were obtained in most of the tracking region. The motion-tracking performance of the new method was compared with a correlation-based exhaustive-search method. For all motion-tracking volume pairs, the average motion-compensated cross-correlation values obtained by the guided-search motion-tracking method were equivalent to those by the exhaustive-search method, and the computation time was about a factor of 10 lesser. Therefore, the proposed 3D ultrasound elasticity imaging method was a more efficient approach to produce a high quality of 3D ultrasound strain image.
Howson, W. P.; Jemah, A. K.; Zhou, J. Q.
1995-06-01
Exact finite elements form the basis of a new and convenient procedure for converging with certainty upon any required natural frequency of out-of-plane motion of any plane structure composed of slender elastic curved members. Solution of the inherent transcendental eigenvalue problem is achieved through a variation on the powerful Wittrick-Williams algorithm. Two illustrative examples are included.
Fu, Y. B.; Ogden, R. W.
2001-05-01
This collection of papers by leading researchers in the field of finite, nonlinear elasticity concerns itself with the behavior of objects that deform when external forces or temperature gradients are applied. This process is extremely important in many industrial settings, such as aerospace and rubber industries. This book covers the various aspects of the subject comprehensively with careful explanations of the basic theories and individual chapters each covering a different research direction. The authors discuss the use of symbolic manipulation software as well as computer algorithm issues. The emphasis is placed firmly on covering modern, recent developments, rather than the very theoretical approach often found. The book will be an excellent reference for both beginners and specialists in engineering, applied mathematics and physics.
Synthesis of 1-D ZnO nanorods and polypyrrole/1-D ZnO ...
Indian Academy of Sciences (India)
... Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM), which gave the evidence of 1-D ZnO nanorods, polymerization of pyrrole monomer and strong interaction between PPy and 1-D ZnO nanorods, respectively. Photocatalytic activity of 1-D ZnO ...
Entanglement Teleportation Through 1D Heisenberg Chain
Hao, X; Zhu, S
2005-01-01
Information transmission of two qubits through two independent 1D Heisenberg chains as a quantum channel is analyzed. It is found that the entanglement of two spin-$\\frac 12$ quantum systems is decreased during teleportation via the thermal mixed state in 1D Heisenberg chain. The entanglement teleportation will be realized if the minimal entanglement of the thermal mixed state is provided in such quantum channel. High average fidelity of teleportation with values larger than 2/3 is obtained w...
Social exploration of 1D games
DEFF Research Database (Denmark)
Valente, Andrea; Marchetti, Emanuela
2013-01-01
In this paper the apparently meaningless concept of a 1 dimensional computer game is explored, via netnography. A small number of games was designed and implemented, in close contact with online communities of players and developers, providing evidence that 1 dimension is enough to produce...... interesting gameplay, to allow for level design and even to leave room for artistic considerations on 1D rendering. General techniques to re-design classic 2D games into 1D are also emerging from this exploration....
Uniqueness in inverse elastic scattering with finitely many incident waves
Energy Technology Data Exchange (ETDEWEB)
Elschner, Johannes [Weierstrass-Institut fuer Angewandte Analysis und Stochastik (WIAS) im Forschungsverbund Berlin e.V. (Germany); Yamamoto, Masahiro [Tokyo Univ. (Japan). Dept. of Mathematical Sciences
2009-07-01
We consider the third and fourth exterior boundary value problems of linear isotropic elasticity and present uniqueness results for the corresponding inverse scattering problems with polyhedral-type obstacles and a finite number of incident plane elastic waves. Our approach is based on a reflection principle for the Navier equation. (orig.)
Thermo elastic waves with thermal relaxation in isotropic micropolar ...
Indian Academy of Sciences (India)
elastic media. In isotropic elastic media Lord & Shulman (1967), Dhaliwal & Sherief (1980) deduced independently the generalized version of classical coupled theory. In the above theories flux rate ...... Eringen A C 1973 Linear theory of non-local microelasticity and dispersion of plane waves. Lett. Appl. Eng. Sci. 1: 11–17.
Tensile Instability in a Thick Elastic Body
Overvelde, Johannes; Dykstra, David; de Rooij, Rijk; Bertoldi, Katia
A range of instabilities can occur in soft bodies that undergo large deformation. While most of them arise under compressive forces, it has previously been shown analytically that a tensile instability can occur in an elastic block subjected to equitriaxial tension. Guided by this result, we conducted centimeter-scale experiments on thick elastomeric samples under generalized plane strain conditions and observed for the first time this elastic tensile instability. We found that equibiaxial stretching leads to the formation of a wavy pattern, as regions of the sample alternatively flatten and extend in the out-of-plane direction. Our work uncovers a new type of instability that can be triggered in elastic bodies, enlarging the design space for smart structures that harness instabilities to enhance their functionality.
Construction of copper-based coordination polymers with 1D chain ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Chemical Sciences; Volume 127; Issue 11. Construction of copper-based coordination polymers with 1D chain, 2D plane and wavy networks: Syntheses, structures, thermal behaviors and photoluminescence properties. Jianghua Li Chi Zhang. Articles Volume 127 Issue 11 November 2015 pp ...
Surface waves in fibre-reinforced anisotropic elastic media
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
MS received 1 March 2002. Abstract. In the paper under discussion, the problem of surface waves in fibre- reinforced anisotropic elastic media has been studied. The authors express the plane strain displacement components in terms of two scalar potentials to decouple the plane motion into P and SV waves. In the present ...
Transmission of longitudinal wave through micro-porous elastic ...
African Journals Online (AJOL)
An investigation of reflection and transmission phenomena of plane longitudinal wave from a plane interface between two distinct micropolar porous elastic solid half-spaces in welded contact has been made. Using the method of potentials, the appropriate boundary conditions at the interface are solved to obtain the ...
Zhao, Xin
2013-05-01
Elastic rods have been studied intensively since the 18th century. Even now the theory of elastic rods is still developing and enjoying popularity in computer graphics and physical-based simulation. Elastic rods also draw attention from architects. Architectural structures, NODUS, were constructed by elastic rods as a new method of form-finding. We study discrete models of elastic rods and NODUS structures. We also develop computational tools to find the equilibria of elastic rods and the shape of NODUS. Applications of elastic rods in forming torus knot and closing Bishop frame are included in this thesis.
Periodic Contact and Crack Problems in Plane Elasticity
DEFF Research Database (Denmark)
Krenk, Steen
1976-01-01
By use of singular integral equations it is demonstrated how some periodic contact and crack problems can be solved in closed form. The integral equation in question is the same which is encountered when dealing with mixed boundary conditions on a circle. As analytical evaluation of the solution ...
Elastic metamaterial beam with remotely tunable stiffness
Qian, Wei; Yu, Zhengyue; Wang, Xiaole; Lai, Yun; Yellen, Benjamin B.
2016-02-01
We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ˜30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.
Elastic metamaterial beam with remotely tunable stiffness
Energy Technology Data Exchange (ETDEWEB)
Qian, Wei [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Yu, Zhengyue [School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Wang, Xiaole [School of Electronic Information and Electrical Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Lai, Yun [College of Physics, Optoelectronics and Energy & Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Yellen, Benjamin B., E-mail: yellen@duke.edu [University of Michigan–Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University, Shanghai 200240 (China); Department of Mechanical Engineering and Materials Science, Duke University, P.O. Box 90300, Hudson Hall, Durham, North Carolina 27708 (United States)
2016-02-07
We demonstrate a dynamically tunable elastic metamaterial, which employs remote magnetic force to adjust its vibration absorption properties. The 1D metamaterial is constructed from a flat aluminum beam milled with a linear array of cylindrical holes. The beam is backed by a thin elastic membrane, on which thin disk-shaped permanent magnets are mounted. When excited by a shaker, the beam motion is tracked by a Laser Doppler Vibrometer, which conducts point by point scanning of the vibrating element. Elastic waves are unable to propagate through the beam when the driving frequency excites the first elastic bending mode in the unit cell. At these frequencies, the effective mass density of the unit cell becomes negative, which induces an exponentially decaying evanescent wave. Due to the non-linear elastic properties of the membrane, the effective stiffness of the unit cell can be tuned with an external magnetic force from nearby solenoids. Measurements of the linear and cubic static stiffness terms of the membrane are in excellent agreement with experimental measurements of the bandgap shift as a function of the applied force. In this implementation, bandgap shifts by as much as 40% can be achieved with ∼30 mN of applied magnetic force. This structure has potential for extension in 2D and 3D, providing a general approach for building dynamically tunable elastic metamaterials for applications in lensing and guiding elastic waves.
PROFILER: 1D galaxy light profile decomposition
Ciambur, Bogdan C.
2017-05-01
Written in Python, PROFILER analyzes the radial surface brightness profiles of galaxies. It accurately models a wide range of galaxies and galaxy components, such as elliptical galaxies, the bulges of spiral and lenticular galaxies, nuclear sources, discs, bars, rings, and spiral arms with a variety of parametric functions routinely employed in the field (Sérsic, core-Sérsic, exponential, Gaussian, Moffat and Ferrers). In addition, Profiler can employ the broken exponential model (relevant for disc truncations or antitruncations) and two special cases of the edge-on disc model: namely along the major axis (in the disc plane) and along the minor axis (perpendicular to the disc plane).
First Observation of Upsilon(1D) States
Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; McGee, S; Bornheim, A; Lipeles, E; Pappas, S P; Shapiro, A; Sun, W M; Weinstein, A J; Mahapatra, R; Briere, R A; Chen, G P; Ferguson, T; Tatishvili, G T; Vogel, H; Adam, N E; Alexander, J P; Berkelman, K; Boisvert, V; Cassel, David G; Drell, P S; Duboscq, J E; Ecklund, K M; Ehrlich, R; Galik, R S; Gibbons, L; Gittelman, B; Gray, S W; Hartill, D L; Heltsley, B K; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Magerkurth, A; Mahlke-Krüger, H; Meyer, T O; Mistry, N B; Nordberg, E; Patterson, J R; Peterson, D; Pivarski, J; Riley, D; Sadoff, A J; Schwarthoff, H; Shepherd, M R; Thayer, J G; Urner, D; Viehhauser, G; Warburton, A; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Potlia, V; Stöck, H; Yelton, J; Brandenburg, G; Kim, D Y J; Wilson, R; Benslama, K; Eisenstein, B I; Ernst, J; Gollin, G D; Hans, R M; Karliner, I; Lowrey, N; Plager, C; Sedlack, C; Selen, M; Thaler, J J; Williams, J; Edwards, K W; Ammar, R; Besson, D; Zhao, X; Anderson, S; Frolov, V V; Kubota, Y; Lee, S J; Li, S Z; Poling, R A; Smith, A; Stepaniak, C J; Urheim, J; Metreveli, Z V; Seth, K K; Tomaradze, A G; Zweber, P; Ahmed, S; Alam, M S; Jian, L; Saleem, M; Wappler, F; Eckhart, E; Gan, K K; Gwon, C; Hart, T; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pedlar, T K; Thayer, J B; Von Törne, E; Wilksen, T; Zoeller, M M; Muramatsu, H; Richichi, S J; Severini, H; Skubic, P L; Dytman, S A; Müller, J A; Nam, S; Savinov, V; Chen, S; Hinson, J W; Lee, J; Miller, D H; Pavlunin, V; Shibata, E I; Shipsey, I P J; Cronin-Hennessy, D; Lyon, A L; Park, C S; Park, W; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Maravin, Y; Stroynowski, R; Artuso, M; Boulahouache, C; Bukin, K; Dambasuren, E; Khroustalev, K; Mountain, R; Nandakumar, R; Skwarnicki, T; Stone, S; Wang, J C; Mahmood, A H
2002-01-01
The CLEO III experiment has recently accumulated a large statistics sample of 4.73 x 10^6 Upsilon(3S) decays. We present the first evidence for the production of the triplet Upsilon(1D) states in the four-photon cascade, Upslion(3S) -> gamma chi_b(2P), chi_b(2P) -> gamma Upsilon(1D), Upsilon(1D) -> gamma chi_b(1P), chi_b(1P) -> gamma Upsilon(1S), followed by the Upsilon(1S) annihilation to e+ e- or mu+ mu-. The signal has a significance of 9.7 standard deviations. The measured product branching ratio for these five decays, (3.3 +- 0.6 +- 0.5) x 10^{-5}, is consistent with the theoretical estimates. We see a 6.8 standard deviation signal for a state with a mass of 10162.2 +- 1.6 MeV/c^2, consistent with the Upsilon(1D_2) assignment. We also present improved measurements of the Upsilon(3S) -> pi0 pi0 Upsilon(1S) branching ratio and the associated di-pion mass distribution.
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...
DEFF Research Database (Denmark)
Hansen, Mads Fogtmann; Fagertun, Jens; Larsen, Rasmus
2011-01-01
This paper presents a fusion of the active appearance model (AAM) and the Riemannian elasticity framework which yields a non-linear shape model and a linear texture model – the active elastic appearance model (EAM). The non-linear elasticity shape model is more flexible than the usual linear...
Surface phenomena in elasticity
Zak, M.
1981-01-01
Problems of elasticity associated with the behavior of free surfaces of elastic bodies are reviewed with particular reference to the propagation of characteristic waves and the criteria of wrinkling of free surfaces. All transformations are given for the case when a free surface of an elastic body is streamlined by the flow of inviscid fluid. The wrinkling phenomenon is illustrated by example.
Barwick, Susan
2008-01-01
Unitals are key structures in projective planes, and have connections with other structures in algebra. This book presents a monograph on unitals embedded in finite projective planes. It offers a survey of the research literature on embedded unitals. It is suitable for graduate students and researchers who want to learn about this topic
Winkler boundary conditions for three-point bending tests on 1D nanomaterials
Gangadean, D.; McIlroy, David N.; Faulkner, Brian E.; Aston, D. Eric
2010-06-01
Bending tests with atomic force microscopes (AFM) is a common method for elasticity measurements on 1D nanomaterials. Interpretation of the force and deflection data is necessary to determine the Young's modulus of the tested material and has been done assuming either of two classic boundary conditions that represent two extreme possibilities for the rigidity of the sample-anchor interface. The elasticity results from the two boundary conditions differ by a factor of four. Furthermore, both boundary conditions ignore the effects of deflections in the anchors themselves. The Winkler model for beams on elastic foundations is developed here for three-point bending tests to provide a more realistic representation. Equations for computing sample elasticity are derived from two sets of boundary conditions for the Winkler model. Application of this model to interpret the measurement of mechanical stiffness of a silica nanowire at multiple points in a three-point bending is discussed. With the correct choice of boundary conditions, the Winkler model gives a better fit for the observed stiffness profile than the classical beam models while providing a result that differs from both by a factor of two and is comparable to the bulk elasticity.
Winkler boundary conditions for three-point bending tests on 1D nanomaterials.
Gangadean, D; McIlroy, David N; Faulkner, Brian E; Aston, D Eric
2010-06-04
Bending tests with atomic force microscopes (AFM) is a common method for elasticity measurements on 1D nanomaterials. Interpretation of the force and deflection data is necessary to determine the Young's modulus of the tested material and has been done assuming either of two classic boundary conditions that represent two extreme possibilities for the rigidity of the sample-anchor interface. The elasticity results from the two boundary conditions differ by a factor of four. Furthermore, both boundary conditions ignore the effects of deflections in the anchors themselves. The Winkler model for beams on elastic foundations is developed here for three-point bending tests to provide a more realistic representation. Equations for computing sample elasticity are derived from two sets of boundary conditions for the Winkler model. Application of this model to interpret the measurement of mechanical stiffness of a silica nanowire at multiple points in a three-point bending is discussed. With the correct choice of boundary conditions, the Winkler model gives a better fit for the observed stiffness profile than the classical beam models while providing a result that differs from both by a factor of two and is comparable to the bulk elasticity.
Grucker, J.; Baudon, J.; Karam, J.-C.; Perales, F.; Bocvarski, V.; Ducloy, M.
2007-04-01
1D and 2D reflection gratings (Permalloy stripes or dots deposited on silicon), immersed in an external homogeneous static magnetic field, are used to study 1D and 2D diffraction of fast metastable helium atoms He* (23S1). Both the grazing incidence used here and the repulsive potential (for sub-level m = -1) generated by the magnetisation reduce the quenching effect. This periodically structured potential is responsible for the diffraction in the incidence plane as well as for the diffraction in the perpendicular plane.
1D and 2D simulations of seismic wave propagation in fractured media
Möller, Thomas; Friederich, Wolfgang
2016-04-01
Fractures and cracks have a significant influence on the propagation of seismic waves. Their presence causes reflections and scattering and makes the medium effectively anisotropic. We present a numerical approach to simulation of seismic waves in fractured media that does not require direct modelling of the fracture itself, but uses the concept of linear slip interfaces developed by Schoenberg (1980). This condition states that at an interface between two imperfectly bonded elastic media, stress is continuous across the interface while displacement is discontinuous. It is assumed that the jump of displacement is proportional to stress which implies a jump in particle velocity at the interface. We use this condition as a boundary condition to the elastic wave equation and solve this equation in the framework of a Nodal Discontinuous Galerkin scheme using a velocity-stress formulation. We use meshes with tetrahedral elements to discretise the medium. Each individual element face may be declared as a slip interface. Numerical fluxes have been derived by solving the 1D Riemann problem for slip interfaces with elastic and viscoelastic rheology. Viscoelasticity is realised either by a Kelvin-Voigt body or a Standard Linear Solid. These fluxes are not limited to 1D and can - with little modification - be used for simulations in higher dimensions as well. The Nodal Discontinuous Galerkin code "neXd" developed by Lambrecht (2013) is used as a basis for the numerical implementation of this concept. We present examples of simulations in 1D and 2D that illustrate the influence of fractures on the seismic wavefield. We demonstrate the accuracy of the simulation through comparison to an analytical solution in 1D.
Reflection of plane waves in an initially stressed perfectly ...
Indian Academy of Sciences (India)
Reflection of plane waves is studied at a free surface of a perfectly conducting transversely isotropic elastic solid half-space with initial stress. The governing equations are solved to obtain the velocity equation which indicates the existence of two quasi planar waves in the medium. Reflection coefficients and energy.
Elastic Equilibrium of Porous Cosserat Media with Double Porosity
Directory of Open Access Journals (Sweden)
Roman Janjgava
2016-01-01
Full Text Available The static equilibrium of porous elastic materials with double porosity is considered in the case of an elastic Cosserat medium. The corresponding three-dimensional system of differential equations is derived. Detailed consideration is given to the case of plane deformation. A two-dimensional system of equations of plane deformation is written in the complex form and its general solution is represented by means of three analytic functions of a complex variable and two solutions of Helmholtz equations. The constructed general solution enables one to solve analytically a sufficiently wide class of plane boundary value problems of the elastic equilibrium of porous Cosserat media with double porosity. A concrete boundary value problem for a concentric ring is solved.
Paro, Alberto
2013-01-01
Written in an engaging, easy-to-follow style, the recipes will help you to extend the capabilities of ElasticSearch to manage your data effectively.If you are a developer who implements ElasticSearch in your web applications, manage data, or have decided to start using ElasticSearch, this book is ideal for you. This book assumes that you've got working knowledge of JSON and Java
2009-09-01
residual stresses. The self- quilibrium conditions result in an integral equation for FI. For inear-elastic constitutive behavior, FI reduces to the unit... integral equation for the average residual elas- tic strain is obtained from the equilibrium conditions requiring the average stress to vanish. It follows...ontinuities across the slip plane in the context of Volterra defects n elastic continua, may also contribute to this plastic deformation 4–7
DEFF Research Database (Denmark)
Jensen, Jonas
This PhD project investigates and further develops methods for ultrasound plane wave imaging and blood flow estimation with the objective of overcoming some of the major limitations in conventional ultrasound systems, which are related to low frame rates and only estimation of velocities along...... the ultrasound beam. The first part of the contribution investigates the compromise between frame rate and plane wave image quality including the influence of grating lobes from a λ-pitch transducer. A method for optimizing the image quality is suggested, and it is shown that the frame rate can be increased...... healthy volunteers. Complex flow patterns were measured in an anthropomorphic flow phantom and showed good agreement with the velocity field simulated using computational fluid dynamics. The last part of the contribution investigates two clinical applications. Plane wave imaging was used for slow velocity...
Transformational plane geometry
Umble, Ronald N
2014-01-01
Axioms of Euclidean Plane Geometry The Existence and Incidence Postulates The Distance and Ruler Postulates The Plane Separation Postulate The Protractor Postulate The Side-Angle-Side Postulate and the Euclidean Parallel Postulate Theorems of Euclidean Plane Geometry The Exterior Angle Theorem Triangle Congruence Theorems The Alternate Interior Angles Theorem and the Angle Sum Theorem Similar Triangles Introduction to Transformations, Isometries, and Similarities Transformations Isometries and SimilaritiesAppendix: Proof of Surjectivity Translations, Rotations, and Reflections Translations Rotations Reflections Appendix: Geometer's Sketchpad Commands Required by Exploratory Activities Compositions of Translations, Rotations, and Reflections The Three Points Theorem Rotations as Compositions of Two Reflections Translations as Compositions of Two Halfturns or Two Reflections The Angle Addition Theorem Glide Reflections Classification of Isometries The Fundamental Theorem and Congruence Classification of Isometr...
Reflection of plane waves at the free surface of a fibre-reinforced ...
Indian Academy of Sciences (India)
The propagation of plane waves in ﬁbre-reinforced, anisotropic, elastic media is discussed. The expressions for the phase velocity of quasi- P ( q P ) and quasi- S V ( q S V ) waves propagating in a plane containing the reinforcement direction are obtained as functions of the angle between the propagation and reinforcement ...
Energy Technology Data Exchange (ETDEWEB)
Lampton, Michael L.; Kim, A.; Akerlof, C.W.; Aldering, G.; Amanullah, R.; Astier, P.; Barrelet, E.; Bebek, C.; Bergstrom, L.; Berkovitz, J.; Bernstein, G.; Bester, M.; Bonissent, A.; Bower, C.; Carithers Jr., W.C.; Commins, E.D.; Day, C.; Deustua, S.E.; DiGennaro,R.; Ealet, A.; Ellis, R.S.; Eriksson, M.; Fruchter, A.; Genat, J.-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Harris, S.E.; Harvey, P.R.; Heetderks, H.D.; Holland, S.E.; Huterer, D.; Karcher, A.; Kolbe, W.; Krieger, B.; Lafever, R.; Lamoureux, J.; Levi, M.E.; Levin, D.S.; Linder,E.V.; Loken, S.C.; Malina, R.; Massey, R.; McKay, T.; McKee, S.P.; Miquel, R.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Pratt, R.; Prieto, E.; Refregier, A.; Rhodes, J.; Robinson, K.; Roe, N.; Sholl, M.; Schubnell, M.; Smadja, G.; Smoot, G.; Spadafora, A.; Tarle, G.; Tomasch,A.; von der Lippe, H.; Vincent, R.; Walder, J.-P.; Wang, G.
2002-07-29
The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square-degree field sensitive in the visible and near-infrared wavelength regime. We describe the requirements for the instrument suite and the evolution of the focal plane design to the present concept in which all the instrumentation--visible and near-infrared imagers, spectrograph, and star guiders--share one common focal plane.
Paro, Alberto
2015-01-01
If you are a developer who implements ElasticSearch in your web applications and want to sharpen your understanding of the core elements and applications, this is the book for you. It is assumed that you've got working knowledge of JSON and, if you want to extend ElasticSearch, of Java and related technologies.
Environmentally Adjusted Elasticity Measures
Shaik, Saleem
2005-01-01
Here, using input, output and nitrogen pollution data related to one state, we propose to extend the elasticity concept to include environmental pollution treated as undesirable output to provide the environmentally adjusted elasticity measures for the period, 1936-1997 in a two-step procedure.
Engineering in-plane silicon nanowire springs for highly stretchable electronics
Xue, Zhaoguo; Dong, Taige; Zhu, Zhimin; Zhao, Yaolong; Sun, Ying; Yu, Linwei
2018-01-01
Crystalline silicon (c-Si) is unambiguously the most important semiconductor that underpins the development of modern microelectronics and optoelectronics, though the rigid and brittle nature of bulk c-Si makes it difficult to implement directly for stretchable applications. Fortunately, the one-dimensional (1D) geometry, or the line-shape, of Si nanowire (SiNW) can be engineered into elastic springs, which indicates an exciting opportunity to fabricate highly stretchable 1D c-Si channels. The implementation of such line-shape-engineering strategy demands both a tiny diameter of the SiNWs, in order to accommodate the strains under large stretching, and a precise growth location, orientation and path control to facilitate device integration. In this review, we will first introduce the recent progresses of an in-plane self-assembly growth of SiNW springs, via a new in-plane solid-liquid-solid (IPSLS) mechanism, where mono-like but elastic SiNW springs are produced by surface-running metal droplets that absorb amorphous Si thin film as precursor. Then, the critical growth control and engineering parameters, the mechanical properties of the SiNW springs and the prospects of developing c-Si based stretchable electronics, will be addressed. This efficient line-shape-engineering strategy of SiNW springs, accomplished via a low temperature batch-manufacturing, holds a strong promise to extend the legend of modern Si technology into the emerging stretchable electronic applications, where the high carrier mobility, excellent stability and established doping and passivation controls of c-Si can be well inherited. Project supported by the National Basic Research 973 Program (No. 2014CB921101), the National Natural Science Foundation of China (No. 61674075), the National Key Research and Development Program of China (No. 2017YFA0205003), the Jiangsu Excellent Young Scholar Program (No. BK20160020), the Scientific and Technological Support Program in Jiangsu Province (No. BE
Elastic interaction of partially debonded circular inclusions. II. Application to fibrous composite
DEFF Research Database (Denmark)
Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon
2011-01-01
A complete analytical solution has been obtained of the elasticity problem for a plane containing periodically distributed, partially debonded circular inclusions, regarded as the representative unit cell model of fibrous composite with interface damage. The displacement solution is written...
Delocalization effects in quasi-1D models with correlated disorder
Energy Technology Data Exchange (ETDEWEB)
Tessieri, L [Instituto de Fisica y Matematicas, Universidad Michoacana de San Nicolas de Hidalgo, Edificio C-3, Ciudad Universitaria, 58060, Morelia, Mich. (Mexico); Izrailev, F M [Instituto de Fisica, Universidad Autonoma de Puebla, Apdo Postal J-48, Puebla, Pue 72570 (Mexico)
2006-09-22
We introduce a new approach to analyse the global structure of electronic states in quasi-1D models in terms of the dynamics of a system of parametric oscillators with time-dependent stochastic couplings. We thus extend to quasi-1D models the method previously applied to 1D disordered models. Using this approach, we show that a 'delocalization transition' can occur in quasi-1D models with weak disorder with long-range correlations.
Escape of O(3P), O(1D), and O(1S) from the Martian atmosphere
Fox, Jane L.; Hać, Aleksander B.
2018-01-01
We have computed here the escape probabilities, fluxes and rates for hot O atoms that are initially produced in the ground state and the first two excited metastable states, O(1D)and O(1S), in the Martian thermosphere by dissociative recombination of O2+. In order to compare our results with those of our previous calculations and with those of others, we have employed here the pre-MAVEN models that we have used previously. To compute the escape probabilities, we have employed the Monte Carlo escape code that has been described previously, but we here use for the first time energy-dependent elastic cross sections for collisions of the energetic O atoms with each of the twelve background species in our model. We also incorporate three mechanisms that interchange identities of the O(3P) and O(1D) atoms, including collisional excitation of O(3P) to O(1D), quenching of O(1D) to O(3P), and excitation exchange of O(1D) with O(3P). We find that the escape probabilities of O atoms that are produced initially as O(1D) are reduced compared to those in which these processes are not included, but the escape probabilities of O atoms that are initially produced as O(3P) are not significantly reduced. As a guide for our future research and those of other investigators, we review here what is known about the interactions of O atoms with other species in which the energies of the O atoms are altered, and several other sources of hot and escaping O, many of which have been suggested by other investigators. We will incorporate these data in a future MAVEN-like model.
Ab initio elastic constants for the lonsdaleite phases of C, Si and Ge
Energy Technology Data Exchange (ETDEWEB)
Wang, S Q [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ye, H Q [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)
2003-08-06
The elastic constants of lonsdaleite C, Si and Ge are calculated by using the plane-wave pseudopotential method in the scheme of density functional theory and the local density approximation. For comparison, the elastic constants of the cubic diamond phases of these elements, zincblende SiC and 6H-SiC, are also calculated.
Ab initio elastic constants for the lonsdaleite phases of C, Si and Ge
Wang, S. Q.; Ye, H. Q.
2003-08-01
The elastic constants of lonsdaleite C, Si and Ge are calculated by using the plane-wave pseudopotential method in the scheme of density functional theory and the local density approximation. For comparison, the elastic constants of the cubic diamond phases of these elements, zincblende SiC and 6H-SiC, are also calculated.
Elastic scattering phenomenology
Energy Technology Data Exchange (ETDEWEB)
Mackintosh, R.S. [The Open University, School of Physical Sciences, Milton Keynes (United Kingdom)
2017-04-15
We argue that, in many situations, fits to elastic scattering data that were historically, and frequently still are, considered ''good'', are not justifiably so describable. Information about the dynamics of nucleon-nucleus and nucleus-nucleus scattering is lost when elastic scattering phenomenology is insufficiently ambitious. It is argued that in many situations, an alternative approach is appropriate for the phenomenology of nuclear elastic scattering of nucleons and other light nuclei. The approach affords an appropriate means of evaluating folding models, one that fully exploits available empirical data. It is particularly applicable for nucleons and other light ions. (orig.)
Elastic and piezoelectric properties, sound velocity and Debye ...
Indian Academy of Sciences (India)
Pseudopotential plane-wave method (PP–PW) based on density functional theory (DFT) and density functional perturbation theory (DFPT) within the Teter and Pade exchangecorrelation functional form of the local spin density approximation (LSDA) is applied to study the effect of pressure on the elastic and piezoelectric ...
Response of orthotropic micropolar elastic medium due to time ...
Indian Academy of Sciences (India)
The present paper is concerned with the plane strain problem in homogeneous micropolar orthotropic elastic solids. The disturbance due to time harmonic concentrated source is investigated by employing eigen-value approach. The integral transforms have been inverted by using a numerical technique to obtain the ...
Response of multiphase magneto-electro-elastic sensors under ...
African Journals Online (AJOL)
The finite element formulation for coupled magneto-electro-elastic sensor bonded to a mild steel beam with plane stress assumption is presented in this paper. The beam is subjected to harmonic excitation with a point load at tip and a uniformly distributed load along the bottom surface of the mild steel beam. Numerical ...
Generalizations of Karp's theorem to elastic scattering theory
Tuong, Ha-Duong
Karp's theorem states that if the far field pattern corresponding to the scattering of a time-harmonic acoustic plane wave by a sound-soft obstacle in R2 is invariant under the group of rotations, then the scatterer is a circle. The theorem is generalized to the elastic scattering problems and the axisymmetric scatterers in R3.
Effect of hydrostatic pressure on the structural, elastic and electronic ...
Indian Academy of Sciences (India)
In this paper we present the results obtained from first-principles calculations of the effect of hydrostatic pressure on the strucural, elastic and electronic properties of (B3) boron phosphide, using the pseudopotential plane-wave method (PP-PW) based on density functional theory within the Teter and Pade ...
Energy Technology Data Exchange (ETDEWEB)
Foda, Omar; Wheeler, Michael [Department of Mathematics and Statistics, University of Melbourne, Parkville, Victoria 3010 (Australia)
2007-01-15
Using BKP neutral fermions, we derive a product expression for the generating function of volume-weighted plane partitions that satisfy two conditions. If we call a set of adjacent equal height-h columns, h > 0, an h-path, then 1. Every h-path can assume one of two possible colours. 2. There is a unique way to move along an h-path from any column to another.
Statistical mechanics of elasticity
Weiner, JH
2012-01-01
Advanced, self-contained treatment illustrates general principles and elastic behavior of solids. Topics include thermoelastic behavior of crystalline and polymeric solids, interatomic force laws, behavior of solids, and thermally activated processes. 1983 edition.
Elastic Properties of Chimpanzee Craniofacial Cortical Bone.
Gharpure, Poorva; Kontogiorgos, Elias D; Opperman, Lynne A; Ross, Callum F; Strait, David S; Smith, Amanda; Pryor, Leslie C; Wang, Qian; Dechow, Paul C
2016-12-01
Relatively few assessments of cranial biomechanics formally take into account variation in the material properties of cranial cortical bone. Our aim was to characterize the elastic properties of chimpanzee craniofacial cortical bone and compare these to the elastic properties of dentate human craniofacial cortical bone. From seven cranial regions, 27 cylindrical samples were harvested from each of five chimpanzee crania. Assuming orthotropy, axes of maximum stiffness in the plane of the cortical plate were derived using modified equations of Hooke's law in a Mathcad program. Consistent orientations among individuals were observed in the zygomatic arch and alveolus. The density of cortical bone showed significant regional variation (P E2 > E1 . Shear moduli were significantly different among regions (P < 0.001). The pattern by which chimpanzee cranial cortical bone varies in elastic properties resembled that seen in humans, perhaps suggesting that the elastic properties of craniofacial bone in fossil hominins can be estimated with at least some degree of confidence. Anat Rec, 299:1718-1733, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.
Jayaram, K.,
2013-01-01
Part 2: Cloud Computing; International audience; For distributed applications to take full advantage of cloud computing systems, we need middleware systems that allow developers to build elasticity management components right into the applications.This paper describes the design and implementation of ElasticRMI, a middleware system that (1) enables application developers to dynamically change the number of (server) objects available to handle remote method invocations with respect to the appl...
Kuc, Rafal
2013-01-01
A practical tutorial that covers the difficult design, implementation, and management of search solutions.Mastering ElasticSearch is aimed at to intermediate users who want to extend their knowledge about ElasticSearch. The topics that are described in the book are detailed, but we assume that you already know the basics, like the query DSL or data indexing. Advanced users will also find this book useful, as the examples are getting deep into the internals where it is needed.
Energy Technology Data Exchange (ETDEWEB)
Reshak, Ali H., E-mail: maalidph@yahoo.co.uk [School of Complex Systems, FFWP, CENAKVA - South Bohemia University CB, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O. Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Jamal, Morteza [School of Complex Systems, FFWP, CENAKVA - South Bohemia University CB, Nove Hrady 37333 (Czech Republic)
2012-12-05
Highlights: Black-Right-Pointing-Pointer A new package for calculating elastic constants of orthorhombic structure is released. Black-Right-Pointing-Pointer The package called ortho-elastic. Black-Right-Pointing-Pointer It is compatible with [FP-(L)APW+lo] method implemented in WIEN2k code. Black-Right-Pointing-Pointer Several orthorhombic structure compounds were used to test the new package. Black-Right-Pointing-Pointer 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{sup Double-Prime }({epsilon}) of polynomial fit E=E({epsilon}) of energy vs strains at zero strain ({epsilon}=0), used to calculate the orthorhombic elastic constants.
Experiments on Elastic Cloaking in Thin Plates
Stenger, Nicolas; Wilhelm, Manfred; Wegener, Martin
2012-01-01
Following a theoretical proposal [M. Farhat , Phys. Rev. Lett. 103, 024301 (2009)PRLTAO0031-900710.1103/PhysRevLett.103.024301], we design, fabricate, and characterize a cloaking structure for elastic waves in 1 mm thin structured polymer plates. The cloak consists of 20 concentric rings of 16 different metamaterials, each being a tailored composite of polyvinyl chloride and polydimethylsiloxane. By using stroboscopic imaging with a camera from the direction normal to the plate, we record movies of the elastic waves for monochromatic plane-wave excitation. We observe good cloaking behavior for carrier frequencies in the range from 200 to 400 Hz (one octave), in good agreement with a complete continuum-mechanics numerical treatment. This system is thus ideally suited for demonstration experiments conveying the ideas of transformation optics.
DEFF Research Database (Denmark)
Manolova, Anna Vasileva; Ruepp, Sarah Renée
2010-01-01
Optical Burst Switching and Generalized Multi-Protocol Label Switching have been around for more than a decade now. The topic of their integration received a fair amount of research interest. This article reviews the main proposed architectures so far and outlines their advantages and drawbacks....... The applicability analysis carried out here focuses on the actual feasibility of the integration and the potential trade-offs which appear when two contradicting principles are combined. Taking advantage of the flexibility of the GMPLS control plane does not seem to be as easy and as straightforward as expected...
Fundamentals of elasticity for Fe-bearing forsterite
Nunez Valdez, M.; Umemoto, K.; Wentzcovitch, R. M.
2009-12-01
We examine the influence of iron in forsterite, the end member of olivine, a major constituent of the Earth's upper mantle. We calculate the elastic properties of Mg2-xFexSiO4, using the plane-wave pseudopotential method for a set of representative upper mantle pressures. We investigate the effect of atomic arrangement and composition on single crystal and poly-crystalline elastic moduli. All nine elastic constants and the isotropic bulk K and shear moduli G are determined under static conditions. We also calculate wave propagation anisotropy in single crystals. Thus a thorough comparison between the elasticity of Fe-bearing and iron-free forsterite is made. Research supported by NSF/ATM 0428774 and EAR 0810272. Computations were performed at the Minnesota Supercomputing Institute.
DEFF Research Database (Denmark)
van der Laan, Paul; Sørensen, Niels N.
2017-01-01
A one-dimensional version of EllipSys, labeled as EllipSys1D is presented. Three atmospheric boundary layer test cases are used to show that results of EllipSys1D are exactly the same or very similar as results of EllipSys3D, while EllipSys1D uses 3 to 4 orders of magnitude less CPU hours compared...
Mosaic Focal Plane Development
Mason, D.; Horner, S.; Aamodt, E.
Advances in manufacturing and applied sciences have enabled the development of large ground and spaced based astronomical instruments having a Field of View (FOV) large enough to capture a large portion of the universe in a single image. A large FOV can be accomplished using light weighted optics, improved structures, and the development of mosaic Focal Plane Assemblies (mFPAs). A mFPA comprises multiple Charged Coupled Devices (CCD) mounted onto a single baseplate integrated at the focus plane of the instrument. Examples of current, or proposed, missions utilizing mFPA technology include FAME, GEST, Kepler, GAIA, LSST, and SNAP. The development of a mFPA mandates tight control on the design trades of component development, CCD definition and characterization, component integration, and performance verification testing. This paper addresses the results of the Lockheed Martin Space Systems Company (LMSSC), Advanced Technology Center (ATC) developed mFPA. The design trades and performance characterization are services provided by the LMSSC ATC but not detailed in this paper.
Static and dynamic overdetermined problems in elasticity, plasticity and post-limit deformation
Chanyshev, A. I.; Belousova, O. E.; Abdulin, I. M.
2017-10-01
Some overdetermined problems, formulated for the Laplace equation in a circle (for arbitrary class of functions, not necessarily analytical) and a half-plane, the heat equation, the one-dimensional wave equation, the elasticity equations for planar deformation, the plasticity and deformations theory problem for a plane with a circular hole, dynamic elasticity theory problems for a half-plane and a half-space with simultaneously known on one its boundary the Dirichlet condition, and the Neumann condition are investigated. Analytical and numerical solutions are constructed, stress-strain states, thermal and other states are restored, internal structure of the body, concentrated sources are determined.
Peselnick, L.; Robie, R.A.
1962-01-01
The recent measurements of the elastic constants of calcite by Reddy and Subrahmanyam (1960) disagree with the values obtained independently by Voigt (1910) and Bhimasenachar (1945). The present authors, using an ultrasonic pulse technique at 3 Mc and 25??C, determined the elastic constants of calcite using the exact equations governing the wave velocities in the single crystal. The results are C11=13.7, C33=8.11, C44=3.50, C12=4.82, C13=5.68, and C14=-2.00, in units of 1011 dyncm2. Independent checks of several of the elastic constants were made employing other directions and polarizations of the wave velocities. With the exception of C13, these values substantially agree with the data of Voigt and Bhimasenachar. ?? 1962 The American Institute of Physics.
Elastic membranes in confinement.
Bostwick, J B; Miksis, M J; Davis, S H
2016-07-01
An elastic membrane stretched between two walls takes a shape defined by its length and the volume of fluid it encloses. Many biological structures, such as cells, mitochondria and coiled DNA, have fine internal structure in which a membrane (or elastic member) is geometrically 'confined' by another object. Here, the two-dimensional shape of an elastic membrane in a 'confining' box is studied by introducing a repulsive confinement pressure that prevents the membrane from intersecting the wall. The stage is set by contrasting confined and unconfined solutions. Continuation methods are then used to compute response diagrams, from which we identify the particular membrane mechanics that generate mitochondria-like shapes. Large confinement pressures yield complex response diagrams with secondary bifurcations and multiple turning points where modal identities may change. Regions in parameter space where such behaviour occurs are then mapped. © 2016 The Author(s).
Elastic anisotropy of crystals
Directory of Open Access Journals (Sweden)
Christopher M. Kube
2016-09-01
Full Text Available An anisotropy index seeks to quantify how directionally dependent the properties of a system are. In this article, the focus is on quantifying the elastic anisotropy of crystalline materials. Previous elastic anisotropy indices are reviewed and their shortcomings discussed. A new scalar log-Euclidean anisotropy measure AL is proposed, which overcomes these deficiencies. It is based on a distance measure in a log-Euclidean space applied to fourth-rank elastic tensors. AL is an absolute measure of anisotropy where the limiting case of perfect isotropy yields zero. It is a universal measure of anisotropy applicable to all crystalline materials. Specific examples of strong anisotropy are highlighted. A supplementary material provides an anisotropy table giving the values of AL for 2,176 crystallite compounds.
Sewell, Thomas D.; Bedrov, Dmitry; Menikoff, Ralph; Smith, Grant D.
2002-07-01
Atomistic molecular dynamics simulations have been used to calculate isothermal elastic properties for beta-, alpha-, and delta-HMX. The complete elastic tensor for each polymorph was determined at room temperature and pressure via analysis of microscopic strain fluctuations using formalism due to Rahman and Parrinello [J. Chem. Phys. 76, 2662 (1982)]. Additionally, the isothermal compression curve was computed for beta-HMX for 0 less-than-or-equal p less-than-or-equal 10.6 GPa; the bulk modulus K and its pressure derivative K'were obtained from two fitting forms employed previously in experimental studies of the beta-HMX equation of state. Overall, the results indicate good agreement between the bulk modulus predicted from the measured and calculated compression curves. The bulk modulus determined directly from the elastic tensor of beta-HMX is in significant disagreement with the compression curve-based results. The explanation for this discrepancy is an area of current research.
Rogozinski, Marek
2014-01-01
This book is a detailed, practical, hands-on guide packed with real-life scenarios and examples which will show you how to implement an ElasticSearch search engine on your own websites.If you are a web developer or a user who wants to learn more about ElasticSearch, then this is the book for you. You do not need to know anything about ElastiSeach, Java, or Apache Lucene in order to use this book, though basic knowledge about databases and queries is required.
Lai, Yun
2011-06-26
Metamaterials can exhibit electromagnetic and elastic characteristics beyond those found in nature. In this work, we present a design of elastic metamaterial that exhibits multiple resonances in its building blocks. Band structure calculations show two negative dispersion bands, of which one supports only compressional waves and thereby blurs the distinction between a fluid and a solid over a finite frequency regime, whereas the other displays super anisotropy-in which compressional waves and shear waves can propagate only along different directions. Such unusual characteristics, well explained by the effective medium theory, have no comparable analogue in conventional solids and may lead to novel applications. © 2011 Macmillan Publishers Limited. All rights reserved.
Crystal structure, characterization and magnetic properties of a 1D ...
Indian Academy of Sciences (India)
A new 1D polymeric copper(II) complex [{Cu(L)(CF3COO)}2]n has been synthesized using a potentially tetradentate Schiff base ... 1D copper(II) polymer; Schiff base; crystal structure; electrochemistry; EPR; magnetic properties. 1. Introduction ... number of copper(II) poly-clusters/assemblies may be mentioned in this regard ...
1D camera geometry and its application to the self-calibration of circular motion sequences.
Wong, Kwan-Yee K; Zhang, Guoqiang; Liang, Chen; Zhang, Hui
2008-12-01
This paper proposes a novel method for robustly recovering the camera geometry of an uncalibrated image sequence taken under circular motion. Under circular motion, all the camera centers lie on a circle and the mapping from the plane containing this circle to the horizon line observed in the image can be modelled as a 1D projection. A 2 x 2 homography is introduced in this paper to relate the projections of the camera centers in two 1D views. It is shown that the two imaged circular points of the motion plane and the rotation angle between the two views can be derived directly from such a homography. This way of recovering the imaged circular points and rotation angles is intrinsically a multiple view approach, as all the sequence geometry embedded in the epipoles is exploited in the estimation of the homography for each view pair. This results in a more robust method compared to those computing the rotation angles using adjacent views only. The proposed method has been applied to self-calibrate turntable sequences using either point features or silhouettes, and highly accurate results have been achieved.
Synthesis, characterization, and physical properties of 1D nanostructures
Marley, Peter Mchael
The roster of materials exhibiting metal---insulator transitions with sharply discontinuous switching of electrical conductivity close to room temperature remains rather sparse despite the fundamental interest in the electronic instabilities manifested in such materials and the plethora of potential technological applications, ranging from frequency-agile metamaterials to electrochromic coatings and Mott field-effect transistors. Vanadium oxide bronzes with the general formula MxV2O 5, provide a wealth of compositions and frameworks where strong electron correlation can be systematically (albeit thus far only empirically) tuned. Charge fluctuations along the quasi-1D frameworks of MxV 2O5 bronzes have evinced much recent interest owing to the manifestation of colossal metal---insulator transitions and superconductivity. We start with a general review on the phase transitions, both electronic and structural, of vanadium oxide bronzes in Chapter 1. In Chapter 2, we demonstrate an unprecedented reversible transformation between double-layered (delta) and tunnel (beta) quasi-1D geometries for nanowires of a divalent vanadium bronze CaxV2O5 (x ˜0.23) upon annealing-induced dehydration and hydrothermally-induced hydration. Such a facile hydration/dehydration-induced interconversion between two prominent quasi-1D structures (accompanied by a change in charge ordering motifs) has not been observed in the bulk and is posited to result from the ease of propagation of crystallographic slip processes across the confined nanowire widths for the delta→beta conversion and the facile diffusion of water molecules within the tunnel geometries for the beta→delta reversion. We demonstrate in Chapter 3 unprecedented pronounced metal-insulator transitions induced by application of a voltage for nanowires of a vanadium oxide bronze with intercalated divalent cations, beta-PbxV 2O5 (x ˜0.33). The induction of the phase transition through application of an electric field at room
Homogenized Elastic Properties of Graphene for Small Deformations
Directory of Open Access Journals (Sweden)
Jurica Sorić
2013-09-01
Full Text Available In this paper, we provide the quantification of the linear and non-linear elastic mechanical properties of graphene based upon the judicious combination of molecular mechanics simulation results and homogenization methods. We clarify the influence on computed results by the main model features, such as specimen size, chirality of microstructure, the effect of chosen boundary conditions (imposed displacement versus force and the corresponding plane stress transformation. The proposed approach is capable of explaining the scatter of the results for computed stresses, energy and stiffness and provides the bounds on graphene elastic properties, which are quite important in modeling and simulation of the virtual experiments on graphene-based devices.
Energy Technology Data Exchange (ETDEWEB)
Popovic, Marta; Zaja, Roko [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia); Fent, Karl [University of Applied Sciences Northwestern Switzerland, School of Life Sciences, Gründenstrasse 40, CH-4132 Muttenz (Switzerland); Swiss Federal Institute of Technology (ETH Zürich), Department of Environmental System Sciences, Institute of Biogeochemistry and Pollution Dynamics, CH-8092 Zürich (Switzerland); Smital, Tvrtko, E-mail: smital@irb.hr [Laboratory for Molecular Ecotoxicology, Division for Marine and Environmental Research, Rudjer Boskovic Institute, Bijenicka 54, 10 000 Zagreb (Croatia)
2014-10-01
Polyspecific transporters from the organic anion transporting polypeptide (OATP/Oatp) superfamily mediate the uptake of a wide range of compounds. In zebrafish, Oatp1d1 transports conjugated steroid hormones and cortisol. It is predominantly expressed in the liver, brain and testes. In this study we have characterized the transport of xenobiotics by the zebrafish Oatp1d1 transporter. We developed a novel assay for assessing Oatp1d1 interactors using the fluorescent probe Lucifer yellow and transient transfection in HEK293 cells. Our data showed that numerous environmental contaminants interact with zebrafish Oatp1d1. Oatp1d1 mediated the transport of diclofenac with very high affinity, followed by high affinity towards perfluorooctanesulfonic acid (PFOS), nonylphenol, gemfibrozil and 17α-ethinylestradiol; moderate affinity towards carbaryl, diazinon and caffeine; and low affinity towards metolachlor. Importantly, many environmental chemicals acted as strong inhibitors of Oatp1d1. A strong inhibition of Oatp1d1 transport activity was found by perfluorooctanoic acid (PFOA), chlorpyrifos-methyl, estrone (E1) and 17β-estradiol (E2), followed by moderate to low inhibition by diethyl phthalate, bisphenol A, 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4 tetrahydronapthalene and clofibrate. In this study we identified Oatp1d1 as a first Solute Carrier (SLC) transporter involved in the transport of a wide range of xenobiotics in fish. Considering that Oatps in zebrafish have not been characterized before, our work on zebrafish Oatp1d1 offers important new insights on the understanding of uptake processes of environmental contaminants, and contributes to the better characterization of zebrafish as a model species. - Highlights: • We optimized a novel assay for determination of Oatp1d1 interactors • Oatp1d1 is the first SLC characterized fish xenobiotic transporter • PFOS, nonylphenol, diclofenac, EE2, caffeine are high affinity Oatp1d1substrates • PFOA, chlorpyrifos
Non-linear elastic deformations
Ogden, R W
1997-01-01
Classic in the field covers application of theory of finite elasticity to solution of boundary-value problems, analysis of mechanical properties of solid materials capable of large elastic deformations. Problems. References.
Asymmetric Vibrations of a Circular Elastic Plate on an Elastic Half Space
DEFF Research Database (Denmark)
Schmidt, H.; Krenk, Steen
1982-01-01
The asymmetric problem of a vibrating circular elastic plate in frictionless contact with an elastic half space is solved by an integral equation method, where the contact stress appears as the unknown function. By a trigonometric expansion, the problem is reduced to a number of uncoupled two......-dimensional problems. The radial variations of contact stresses and surface displacements are represented by polynomials, the coefficients of which are directly related by an infinite matrix that is a function of the vibration frequency. The results include a parametric study of the power input as a function...... of the vibration frequency of various plate stiffnesses and the normal component of the surface displacement field for simple excitation of the plate and passage of a plane Rayleigh wave....
Error Analysis on Plane-to-Plane Linear Approximate Coordinate ...
Indian Academy of Sciences (India)
c Indian Academy of Sciences. Error Analysis on Plane-to-Plane Linear Approximate Coordinate. Transformation. Q. F. Zhang1,∗, Q. Y. Peng1 & J. H. Fan2. 1Department of Computer Science, Jinan University, Guangzhou 510632, China. ... This work is partially supported by the National Natural Science Foundation.
Multiplet structure of the defect modes in 1D helical photonic crystals with twist defects
Avendaño, C. G.; Ponti, S.; Reyes, J. A.; Oldano, C.
2005-10-01
We theoretically analyse the defect modes generated by equispaced twist defects in 1D helical (cholesteric-like) structures within their frequency gap which is such that only the first two of the four eigenwaves 1±, 2± are exponentially attenuated. n0 identical defects generate n0 different defect modes, each one represented by a linear combination of the four eigenwaves. The components 1+ and 1- are by far the dominant ones and they are localized near the defect planes. We give exact analytic expressions for the elements of the transfer and scattering matrices of the defect planes, for the functions defining the defect mode when n0 = 1, and for the defect frequencies when n0 = 1, 2, 3. In the particular case n0 = 2 and twist angle θ = π/2, the difference between the two defect wavelengths λd2, λd1 depends exponentially on the distance z1 between the defect planes, going to zero for z1 → ∞ and becoming as large as the entire frequency gap for z1 → 0.
Sadeghian, H.; Goosen, J.F.L.; Bossche, A.; Van Keulen, F.
2009-01-01
In this letter, the dominant role of surface stress and surface elasticity on the overall elastic behavior of ultrathin cantilever plates is studied. A general framework based on two-dimensional plane-stress analysis is presented. Because of either surface reconstruction or molecular adsorption,
1D photonic crystal sensor integrated in a microfluidic system
DEFF Research Database (Denmark)
Nunes, Pedro; Mortensen, Asger; Kutter, Jörg Peter
2009-01-01
A refractive index sensor was designed as a 1D resonator incorporated in a microfluidic channel, where aqueous solutions were injected. A sensitivity of 480 nm/RIU and a minimum difference of Deltan = 0.002 were determined.......A refractive index sensor was designed as a 1D resonator incorporated in a microfluidic channel, where aqueous solutions were injected. A sensitivity of 480 nm/RIU and a minimum difference of Deltan = 0.002 were determined....
Intrinsically polarized elastic metamaterial
Bilal, Osama; Suesstrunk, Roman; Huber, Sebastian; Daraio, Chiara
Mechanical metamaterials, with periodically repeating basic building blocks in space, expand the envelope of possible properties of matter. Metamaterials harness their effective properties through structure rather than chemical composition. Successful implementations of such materials enabled the realization of ultrastiff-utralight materials, negative Poisson ratio materials, and fluid-like solids. In this work, we theoretically analyze and experimentally implement a new design principle for mechanical metamaterials. By combining states of self-stress, topological invariants and additive manufacturing techniques, we realize a new class of three-dimensional mechanical metamaterials with polar elasticity. The fabricated specimens show, at two of its opposing faces along the same axis, an asymmetric elastic response (i.e., soft on one face and harder on the other). We design our lattice to retain angular dependency to a perpendicular load, providing a direct experimental observation of nodal Weyl lines.
Introduction to linear elasticity
Gould, Phillip L
2013-01-01
Introduction to Linear Elasticity, 3rd Edition, provides an applications-oriented grounding in the tensor-based theory of elasticity for students in mechanical, civil, aeronautical, and biomedical engineering, as well as materials and earth science. The book is distinct from the traditional text aimed at graduate students in solid mechanics by introducing the subject at a level appropriate for advanced undergraduate and beginning graduate students. The author's presentation allows students to apply the basic notions of stress analysis and move on to advanced work in continuum mechanics, plasticity, plate and shell theory, composite materials, viscoelasticity and finite method analysis. This book also: Emphasizes tensor-based approach while still distilling down to explicit notation Provides introduction to theory of plates, theory of shells, wave propagation, viscoelasticity and plasticity accessible to advanced undergraduate students Appropriate for courses following emerging trend of teaching solid mechan...
Shaheen, Aliah F; Bull, Anthony M J; Alexander, Caroline M
2015-02-01
Rigid and Elastic scapular taping is used in physical rehabilitation of shoulder impingement syndrome (SIS). It is believed to reduce pain and normalise scapular movement patterns. However, there is insufficient evidence to support its use. The aim of the study was to investigate the effect of Rigid and Elastic taping techniques on the scapular kinematics and pain in patients with SIS. Eleven patients with SIS participated in the study. They performed elevation and lowering of the arm in the scapular and sagittal planes under three conditions: Baseline, Rigid taping and Elastic taping. The movements of the thorax, humerus and scapula were tracked. Scapular displacements and scapulothoracic joint rotations were calculated. Subjects used a visual analogue scale to rate the intensity of pain at rest and during movements in both planes. Both taping techniques externally rotated the scapula in sagittal plane movements (ppain. In the scapular plane, Elastic taping increased the scapular retraction (ppain in this plane. In conclusion, both taping techniques had an effect on scapular kinematics and pain in movements occurring in the sagittal plane. Elastic taping also affected scapular kinematics in scapular plane movements, but without the concomitant decrease in pain. Copyright © 2014 Elsevier Ltd. All rights reserved.
Monitoring heat-induced changes in soft tissues with 1D transient elastography
Energy Technology Data Exchange (ETDEWEB)
Benech, Nicolas; Negreira, Carlos A [Laboratorio de Acustica Ultrasonora, Facultad de Ciencias, Igua 4225, 11400, Montevideo (Uruguay)
2010-03-21
In this paper 1D transient elastography was employed in fresh bovine skeletal muscle samples to assess the shear elastic modulus {mu} while the tissue was locally heated by means of an electrical resistance. The investigation is based on the study of the time shift of the shear wave propagation produced by the local temperature variation. The experiments show that the thermal expansion contribution to the time shift is negligible when compared with the shear wave speed variation. In such a case, the quantification of {mu} as a function of temperature becomes possible. Repeated experiments in different samples lead to a reproducible behavior of {mu} as a function of temperature. Irreversible elasticity changes are produced when the temperature exceeds a certain critical value T{sub c}. The proposed method allows estimating this value as well as the spatial extension of the resulting thermal lesion. This point is important when considering applications in monitoring focused ultrasound surgery (FUS) because the surrounding normal tissue should remain unaffected.
Elastic scattering of surface plasmon polaritons: Modeling and experiment
DEFF Research Database (Denmark)
Bozhevolnyi, Sergey I.; Coello, V.
1998-01-01
Elastic (in-plane) scattering of surface plasmon polaritons (SPP's) is modeled by considering isotropic pointlike scatterers whose responses to the incident SPP field are phenomenologically related to their effective polarizabilities. Numerical simulations of single, double, and multiple scattering...... are presented for randomly situated scatterers showing the interplay between different orders of scattering and localization phenomena. Correlation between the scattering regimes and spatial Fourier spectra of the corresponding SPP intensity distributions is considered. Various optical microcomponents (e...
Vibrations of Elastic Systems With Applications to MEMS and NEMS
Magrab, Edward B
2012-01-01
This work presents a unified approach to the vibrations of elastic systems as applied to MEMS devices, mechanical components, and civil structures. Applications include atomic force microscopes, energy harvesters, and carbon nanotubes and consider such complicating effects as squeeze film damping, viscous fluid loading, in-plane forces, and proof mass interactions with their elastic supports. These effects are analyzed as single degree-of-freedom models and as more realistic elastic structures. The governing equations and boundary conditions for beams, plates, and shells with interior and boundary attachments are derived by applying variational calculus to an expression describing the energy of the system. The advantages of this approach regarding the generation of orthogonal functions and the Rayleigh-Ritz method are demonstrated. A large number of graphs and tables are given to show the impact of various factors on the systems’ natural frequencies, mode shapes, and responses.
Flores Parra, Edgar A.; Bergamini, Andrea; Kamm, Lars; Zbinden, Paul; Ermanni, Paolo
2017-06-01
This paper reports on the first implementation of an integrated programmable hybrid phononic crystal (hPC) for wave propagation control. At the core of the novel hPC is a newly developed and tested miniaturized array of virtual floating inductances with programmable properties. The inductance is the building block for a discrete programmable electrical transmission line aimed at wave propagation control in a 1D hPC. The hybrid characteristic is the result of the coupling between a mechanical waveguide in the form of an elastic beam, and an electrical transmission line. The medium features attenuation of mechanical wave motion due to an energy transfer to the electrical domain. Over the frequency range of wave attenuation the dispersion curves of the hPC are characterized by eigenvalue mode veering. An analytical model, based on the transfer matrix method is presented, to expeditiously calculate the dispersion curves of the hPC. Furthermore, this paper provides numerical and experimental transmittance results which validate the efficiency and tunability of the programmable electrical transmission line. The novelty of this contribution is an analytical model for calculating the dispersion curves of the 1D hPC, and a miniaturized programmable virtual inductance which gives way to a ‘smart’ material.
Resonant indirect exchange in 1D semiconductor nanostructures
Energy Technology Data Exchange (ETDEWEB)
Rozhansky, I.V., E-mail: rozhansky@gmail.com [Ioffe Institute, Russian Academy of Sciences, St.Petersburg 194021 (Russian Federation); Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland); St. Petersburg State Polytechnic University, St. Petersburg 195251 (Russian Federation); Krainov, I.V.; Averkiev, N.S. [Ioffe Institute, Russian Academy of Sciences, St.Petersburg 194021 (Russian Federation); Lähderanta, E. [Lappeenranta University of Technology, P.O. Box 20, FI-53851 Lappeenranta (Finland)
2015-06-01
We consider resonant indirect exchange interaction between magnetic centers in 1D nanostructures. The magnetic centers are assumed to be coupled to the 1D conducting channel by the quantum tunneling which can be of resonant character. The indirect exchange between the centers is mediated by the free carriers of the channel. The two cases of quadratic and linear energy dispersion of the 1D free carriers are considered. The former case is attributed to conventional semiconductor (InGaAs based to be concrete) nanowires or nanowhiskers, while the latter case is associated with carbon nanotubes with magnetic adatoms. We demonstrate that whenever the energy of a bound state at the magnetic center lies within the continuum energy spectra of the delocalized carriers in the channel the indirect exchange is strongly enhanced due to effective tunnel hybridization of the bound states with the continuum. - Highlights: • A resonant indirect exchange interaction between magnetic centers mediated by a 1D conducting channel is considered. • It is shown that the indirect exchange is strongly enhanced due to resonant tunnel coupling of a magnetic bound state with the delocalized states. • The two cases of quadratic and linear energy dispersion of the 1D free carriers are considered. • Pecularities of the indirect exchange mediated by a carbon nanotube has been investigated.
Form finding in elastic gridshells.
Baek, Changyeob; Sageman-Furnas, Andrew O; Jawed, Mohammad K; Reis, Pedro M
2017-12-18
Elastic gridshells comprise an initially planar network of elastic rods that are actuated into a shell-like structure by loading their extremities. The resulting actuated form derives from the elastic buckling of the rods subjected to inextensibility. We study elastic gridshells with a focus on the rational design of the final shapes. Our precision desktop experiments exhibit complex geometries, even from seemingly simple initial configurations and actuation processes. The numerical simulations capture this nonintuitive behavior with excellent quantitative agreement, allowing for an exploration of parameter space that reveals multistable states. We then turn to the theory of smooth Chebyshev nets to address the inverse design of hemispherical elastic gridshells. The results suggest that rod inextensibility, not elastic response, dictates the zeroth-order shape of an actuated elastic gridshell. As it turns out, this is the shape of a common household strainer. Therefore, the geometry of Chebyshev nets can be further used to understand elastic gridshells. In particular, we introduce a way to quantify the intrinsic shape of the empty, but enclosed regions, which we then use to rationalize the nonlocal deformation of elastic gridshells to point loading. This justifies the observed difficulty in form finding. Nevertheless, we close with an exploration of concatenating multiple elastic gridshell building blocks.
Mathematical foundations of elasticity
Marsden, Jerrold E
1994-01-01
This advanced-level study approaches mathematical foundations of three-dimensional elasticity using modern differential geometry and functional analysis. It is directed to mathematicians, engineers and physicists who wish to see this classical subject in a modern setting with examples of newer mathematical contributions. Prerequisites include a solid background in advanced calculus and the basics of geometry and functional analysis.The first two chapters cover the background geometry ― developed as needed ― and use this discussion to obtain the basic results on kinematics and dynamics of con
Thermally Driven Elastic Micromachines
Hosaka, Yuto; Yasuda, Kento; Sou, Isamu; Okamoto, Ryuichi; Komura, Shigeyuki
2017-11-01
We discuss the directional motion of an elastic three-sphere micromachine in which the spheres are in equilibrium with independent heat baths having different temperatures. Even in the absence of prescribed motion of springs, such a micromachine can gain net motion purely because of thermal fluctuations. A relation connecting the average velocity and the temperatures of the spheres is analytically obtained. This velocity can also be expressed in terms of the average heat flows in the steady state. Our model suggests a new mechanism for the locomotion of micromachines in nonequilibrium biological systems.
Quantum electrodynamics with 1D arti cial atoms
DEFF Research Database (Denmark)
Javadi, Alisa
A 1D atom, a single quantum emitter coupled to a single optical mode, exhibits rich quantum electrodynamic (QED) e_ects and is thought to be the key ingredient for many applications in quantuminformation processing. Single quantum dots (QD) in photonic-crystal waveguides (PCW) constitute a robust...... platform for realizing a 1D atom, and are the subject of theoretical and experimental investigations in this thesis. We use _nite element method in 3D to calculate the local density of states (LDOS) in photonic-crystal membranes. The detailed spatial maps show strong inhibition of LDOS in the bandgap...... atom. One of the signatures and functions of a 1D atom is the nonlinear optical response at the single-photon level. A PCW chip is designed to experimentally study the transmission spectrum of an embedded QD. The transmission spectrum is shown to be modi_ed by 30% around the resonance of the QD...
Free Vibration and Dynamic Stability of Functionally Graded Material Plates on Elastic Foundation
I. Ramu; S.C. Mohanty
2015-01-01
The study of parametric resonance characteristics of functionally-graded material (FGM) plates on elastic foundation is proposed under biaxial in plane periodic load. Finite element method in conjunction with Hamilton’s principle is utilised to establish the governing equations in a discrete form, Floquet’s theory was applied to determine the instability regions of FGM plate resting on elastic foundation. The effects of power law index, temperature rise, and foundation coefficients on the nat...
GIS-BASED 1-D DIFFUSIVE WAVE OVERLAND FLOW MODEL
Energy Technology Data Exchange (ETDEWEB)
KALYANAPU, ALFRED [Los Alamos National Laboratory; MCPHERSON, TIMOTHY N. [Los Alamos National Laboratory; BURIAN, STEVEN J. [NON LANL
2007-01-17
This paper presents a GIS-based 1-d distributed overland flow model and summarizes an application to simulate a flood event. The model estimates infiltration using the Green-Ampt approach and routes excess rainfall using the 1-d diffusive wave approximation. The model was designed to use readily available topographic, soils, and land use/land cover data and rainfall predictions from a meteorological model. An assessment of model performance was performed for a small catchment and a large watershed, both in urban environments. Simulated runoff hydrographs were compared to observations for a selected set of validation events. Results confirmed the model provides reasonable predictions in a short period of time.
Energy Technology Data Exchange (ETDEWEB)
Toth, G.; Zavodszky, P.; Bhalla, C.P.; Richard, P.; Grabbe, S.; Aliabadi, H. [Kansas State Univ., Manhattan, KS (United States). Dept. of Physics
2001-07-01
Absolute double differential cross sections for the electron production at zero degree laboratory observation angle were measured for high velocity hydrogenic carbon, nitrogen, oxygen and fluorine ions on molecular hydrogen. The energies of these ions were chosen so the elastic scattering resonance 2p{sup 2} {sup 1}D for each case can be clearly observed near the peak of the binary encounter electron distribution. Close coupling R-matrix calculations of elastic differential cross sections of electron impact of these ions were related to the measured ion-atom cross sections by using the elastic scattering model (ESM). Excellent agreement was found between theory and experimental data. (orig.)
One-electron singular spectral features of the 1D Hubbard model at finite magnetic field
Directory of Open Access Journals (Sweden)
J.M.P. Carmelo
2017-01-01
Full Text Available The momentum, electronic density, spin density, and interaction dependences of the exponents that control the (k,ω-plane singular features of the σ=↑,↓ one-electron spectral functions of the 1D Hubbard model at finite magnetic field are studied. The usual half-filling concepts of one-electron lower Hubbard band and upper Hubbard band are defined in terms of the rotated electrons associated with the model Bethe-ansatz solution for all electronic density and spin density values and the whole finite repulsion range. Such rotated electrons are the link of the non-perturbative relation between the electrons and the pseudofermions. Our results further clarify the microscopic processes through which the pseudofermion dynamical theory accounts for the one-electron matrix elements between the ground state and excited energy eigenstates.
Energy Technology Data Exchange (ETDEWEB)
Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.
1988-12-01
Elastic emission polishing, also called elastic emission machining (EEM), is a process where a stream of abrasive slurry is used to remove material from a substrate and produce damage free surfaces with controlled surface form. It is a noncontacting method utilizing a thick elasto-hydrodynamic film formed between a soft rotating ball and the workpiece to control the flow of the abrasive. An apparatus was built in the Center, which consists of a stationary spindle, a two-axis table for the workpiece, and a pump to circulate the working fluid. The process is controlled by a programmable computer numerical controller (CNC), which presently can operate the spindle speed and movement of the workpiece in one axis only. This apparatus has been used to determine material removal rates on different material samples as a function of time, utilizing zirconium oxide (ZrO{sub 2}) particles suspended in distilled water as the working fluid. By continuing a study of removal rates the process should become predictable, and thus create a new, effective, yet simple tool for ultra-precision mechanical machining of surfaces.
Elastic behaviour of North Sea chalk
DEFF Research Database (Denmark)
Gommesen, Lars; Fabricius, Ida Lykke; Mukerji, T.
2007-01-01
chalk. In the acoustic impedance–Poisson's ratio plane, we forecast variations in porosity and hydrocarbon saturation from their influence on the elastic behaviour of the chalk. The Gassmann model and the self-consistent approximation give roughly similar predictions of the effect of fluid on acoustic...... impedance and Poisson's ratio, but we find that the high-frequency self-consistent approach gives a somewhat smaller predicted fluid-saturation effect on Poisson's ratio than the low-frequency Gassmann model. The Gassmann prediction for the near and potentially invaded zone corresponds more closely...... to logging data than the Gassmann prediction for the far, virgin zone. We thus conclude that the Gassmann approach predicts hydrocarbons accurately in chalk in the sonic-frequency domain, but the fluid effects as recorded by the acoustic tool are significantly affected by invasion of mud filtrate...
Elasticity of polymeric nanocolloidal particles
National Research Council Canada - National Science Library
Riest, Jonas; Athanasopoulou, Labrini; Egorov, Sergei A; Likos, Christos N; Ziherl, Primož
2015-01-01
.... Elasticity of individual particles directly controls their swelling, wetting, and adsorption behaviour, their aggregation and self-assembly as well as structural and rheological properties of suspensions...
Medical Ultrasonic Elasticity Imaging Techniques
Energy Technology Data Exchange (ETDEWEB)
Jeong, Mok Keun [Department of Electronics and Communications Engineering, Daejin University, Pocheon (Korea, Republic of)
2012-10-15
Breast and prostate tumors or cancers tend to be stiffer than the surrounding normal tissue. However, the difference in echogenicity between cancerous and normal tissues is not clearly distinguishable in ultrasound B-mode imaging. Thus, imaging the stiffness contrast between the two different tissue types helps to diagnose lesions quantitatively, and such a method of imaging the elasticity of human tissue is termed ultrasound elasticity imaging. Recently, elasticity imaging has become an effective complementary diagnostic modality along with ultrasound B-mode imaging. This paper presents various elasticity imaging methods that have been reported up to now and describes their characteristics and principles of operation.
Ultrafast vascular strain compounding using plane wave transmission.
Hansen, H H G; Saris, A E C M; Vaka, N R; Nillesen, M M; de Korte, C L
2014-03-03
Deformations of the atherosclerotic vascular wall induced by the pulsating blood can be estimated using ultrasound strain imaging. Because these deformations indirectly provide information on mechanical plaque composition, strain imaging is a promising technique for differentiating between stable and vulnerable atherosclerotic plaques. This paper first explains 1-D radial strain estimation as applied intravascularly in coronary arteries. Next, recent methods for noninvasive vascular strain estimation in a transverse imaging plane are discussed. Finally, a compounding technique that our group recently developed is explained. This technique combines motion estimates of subsequently acquired focused ultrasound images obtained at various insonification angles. However, because the artery moves and deforms during the multi-angle acquisition, errors are introduced when compounding. Recent advances in computational power have enabled plane wave ultrasound acquisition, which allows 100 times faster image acquisition and thus might resolve the motion artifacts. In this paper the performance of strain imaging using plane wave compounding is investigated using simulations of an artery with a vulnerable plaque and experimental data of a two-layered vessel phantom. The results show that plane wave compounding outperforms 0° focused strain imaging. For the simulations, the root mean squared error reduced by 66% and 50% for radial and circumferential strain, respectively. For the experiments, the elastographic signal-to-noise and contrast-to-noise ratio (SNR(e) and CNR(e)) increased with 2.1 dB and 3.7 dB radially, and 5.6 dB and 16.2dB circumferentially. Because of the high frame rate, the plane wave compounding technique can even be further optimized and extended to 3D in future. Copyright © 2014 Elsevier Ltd. All rights reserved.
Energy harvesting and storage in 1D devices
Sun, Hao; Zhang, Ye; Zhang, Jing; Sun, Xuemei; Peng, Huisheng
2017-06-01
Power systems and electronic devices that are bulky and rigid are not practical for use in wearable applications that require flexibility and breathability. To address this, a range of 1D energy harvesting and storage devices have been fabricated that show promise for such applications compared with their 2D and 3D counterparts. These 1D devices are based on fibres that are flexible and can accommodate deformation, for example, by twisting and stretching. The fibres can be woven into textiles and fabrics that breathe freely or can be integrated into different materials that fit the curved surface of the human body. In this Review, the development of fibre-based energy harvesting and storage devices is presented, focusing on dye-sensitized solar cells, lithium-ion batteries, supercapacitors and their integrated devices. An emphasis is placed on the interface between the active materials and the electrodes or electrolyte in the 1D devices. The differing properties of these interfaces compared with those in 2D and 3D devices are derived from the curved surface and long charge transport path in 1D electrodes.
ZnO 1-D nanostructures: Low temperature synthesis and ...
Indian Academy of Sciences (India)
Wintec
Among various nanostructures, ori- ented 1-D nanoforms are particularly important for applications such as UV laser, sensors, UV LED, field emission ... Gas phase growth techniques like chemi- cal vapour deposition (CVD), ..... Greene L E, Law M, Goldberger J, Kim F, Johnson J C, Zhang. Y, Saykally R J and Yang P 2003 ...
Active damping of the 1D rocking mode
Babakhani, B.; de Vries, Theodorus J.A.
Active damping of a rotational vibration mode in the linear guidance of a precision machine in a one dimensional (1D) setting is considered in this paper. This so-called rocking mode presents itself in machines having linear actuation. The limitation this vibration mode imposes on the machine
Performance studies on high pressure 1-D position sensitive ...
Indian Academy of Sciences (India)
Performance studies on high pressure 1-D position sensitive neutron detectors. S S DESAI and A M SHAIKH∗. Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. *Corresponding author. E-mail: shaikham@barc.gov.in. Abstract. The powder diffractometer and Hi-Q diffractometer at ...
Inverse parameter identification for a branching 1D arterial network
CSIR Research Space (South Africa)
Bogaers, Alfred EJ
2012-07-01
Full Text Available In this paper we investigate the invertability of a branching 1D arterial blood flow network. We limit our investigation to a single bifurcating vessel, where the material properties, unloaded areas and variables characterizing the input and output...
Crystal structure, characterization and magnetic properties of a 1D ...
Indian Academy of Sciences (India)
Home; Journals; Journal of Chemical Sciences; Volume 128; Issue 6. Crystal structure, characterization and magnetic properties of a 1D copper(II) polymer incorporating a Schiff base with carboxylate side arm. SHYAMAPADA SHIT MADHUSUDAN NANDY CORRADO RIZZOLI CÉDRIC DESPLANCHES SAMIRAN MITRA.
Two-phase 1D+1D model of a DMFC: development and validation on extensive operating conditions range
Energy Technology Data Exchange (ETDEWEB)
Casalegno, A.; Marchesi, R.; Parenti, D. [Dipartimento di Energetica, Politecnico di Milano (Italy)
2008-02-15
A two-phase 1D+1D model of a direct methanol fuel cell (DMFC) is developed, considering overall mass balance, methanol transport in gas phase through anode diffusion layer, methanol and water crossover. The model is quantitatively validated on an extensive range of operating conditions, 24 polarisation curves. The model accurately reproduces DMFC performance in the validation range and, outside this, it is able to predict values under feasible operating conditions. Finally, the estimations of methanol crossover flux are qualitatively and quantitatively similar to experimental measures and the main local quantities' trends are coherent with results obtained with more complex models. (Abstract Copyright [2008], Wiley Periodicals, Inc.)
Wrinkling in the deflation of elastic bubbles
Aumaitre, Elodie
2013-03-01
The protein hydrophobin HFBII self-assembles into very elastic films at the surface of water; these films wrinkle readily upon compression. We demonstrate and study this wrinkling instability in the context of non-planar interfaces by forming HFBII layers at the surface of bubbles whose interfaces are then compressed by deflation of the bubble. By varying the initial concentration of the hydrophobin solutions, we are able to show that buckling occurs at a critical packing fraction of protein molecules on the surface. Independent experiments show that at this packing fraction the interface has a finite positive surface tension, and not zero surface tension as is usually assumed at buckling. We attribute this non-zero wrinkling tension to the finite elasticity of these interfaces. We develop a simple geometrical model for the evolution of the wrinkle length with further deflation and show that wrinkles grow rapidly near the needle (used for deflation) towards the mid-plane of the bubble. This geometrical model yields predictions for the length of wrinkles in good agreement with experiments independently of the rheological properties of the adsorbed layer. © 2013 EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg.
Elasticplastic discs under plane stress conditions
Alexandrov, Sergey
2015-01-01
This Volume presents a unified approach to calculate the plane stress distribution of stress and strain in thin elastic/plastic discs subject to various loading conditions. There is a vast amount of literature on analytical and semi-analytical solutions for such discs obeying Tresca’s yield criterion and its associated flow rule. On the other hand, most of analytical and semi-analytical solutions for Mises yield criterion are based on the deformation theory of plasticity. A distinguished feature of the solutions given in the present volume is that the flow theory of plasticity and Mises yield criterion are adopted. The solutions are semi-analytical in the sense that numerical methods are only necessary to evaluate ordinary integrals and solve transcendental equations. The book shows that under certain conditions solutions based on the deformation and flow theories of plasticity coincide. All the solutions are illustrated with numerical examples. The goal of the book is to provide the reader with a vision an...
Rajapitamahuni, Anil; Zhang, Le; Singh, Vijay; Burton, John; Koten, Mak; Shield, Jeffrey; Tsymbal, Evgeny; Hong, Xia
We report a unusual giant enhancement of in-plane magnetocrystalline anisotropy (MCA) in ultrathin colossal magnetoresistive oxide films due to 1D nanoscale periodic depth modulation. High quality epitaxial thin films of La0.67Sr0.33MnO3 (LSMO) of thickness 6 nm were grown on (001) SrTiO3 substrates via off-axis radio frequency magnetron sputtering. The top 2 nm of LSMO films are patterned into periodic nano-stripes using e-beam lithography and reactive ion etching. The resulting structure consists of nano-stripes of 2 nm height and 100-200 nm width on top of a 4 nm thick continuous base layer. We employed planar Hall effect measurements to study the in-plane magnetic anisotropy of the unpatterned and nanopatterned films. The unpatterned films show a biaxial anisotropy with easy axis along [110]. The extracted anisotropy energy density is ~1.1 x 105 erg/cm3, comparable to previously reported values. In the nanopatterned films, a strong uniaxial anisotropy is developed along one of the biaxial easy axes. The corresponding anisotropy energy density is ~5.6 x 106 erg/cm3 within the nano-striped volume, comparable to that of Co. We attribute the observed uniaxial MCA to MnO6 octahedral rotations/tilts and the enhancement in the anisotropy energy density to the strain gradient within the nano-stripes.
Measurement of the elastic cross section for positive pions on carbon at 142 MeV
Energy Technology Data Exchange (ETDEWEB)
Oyer, A.T.
1976-12-01
A measurement of the elastic cross section dsigma/d..cap omega.. was made for the reaction ..pi../sup +/ + /sup 12/C ..-->.. ..pi../sup +/ + /sup 12/C with 142 MeV pions at ten angles ranging from 35 to 85/sup 0/ in the laboratory. This experiment was done at the Los Alamos Meson Physics Facility. A double focusing magnetic spectrometer observed a cylindrical styrofoam target. The resulting momentum spectra were recorded by an array of nineteen totally depleted surface barrier detectors located at the spectrometer's focal plane. The spectra from the styrofoam were composed of peaks representing proton elastic, carbon elastic, carbon inelastic, and carbon quasi-elastic channels. A function made of Gaussians representing the two body channels and a distribution representing the quasi-elastic channel was fit to the data using a nonlinear least squares algorithm. The ratio of the carbon elastic to proton elastic cross sections was calculated from the areas of the corresponding Gaussians and then multiplied by the proton elastic cross section of Bugg et al eliminating several sources of systematic errors such as beam normalization. The differential cross sections were found to have the usual diffraction structure with a forward peak and a minimum near 55/sup 0/. Finally, the carbon elastic cross sections were compared to similar ..pi../sup -/ + /sup 12/C cross sections of Binon et al using the optical model.
Engelbrecht, Jüri
2015-01-01
This book addresses the modelling of mechanical waves by asking the right questions about them and trying to find suitable answers. The questions follow the analytical sequence from elementary understandings to complicated cases, following a step-by-step path towards increased knowledge. The focus is on waves in elastic solids, although some examples also concern non-conservative cases for the sake of completeness. Special attention is paid to the understanding of the influence of microstructure, nonlinearity and internal variables in continua. With the help of many mathematical models for describing waves, physical phenomena concerning wave dispersion, nonlinear effects, emergence of solitary waves, scales and hierarchies of waves as well as the governing physical parameters are analysed. Also, the energy balance in waves and non-conservative models with energy influx are discussed. Finally, all answers are interwoven into the canvas of complexity.
PAGOSA Sample Problem. Elastic Precursor
Energy Technology Data Exchange (ETDEWEB)
Weseloh, Wayne N. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Clancy, Sean Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2016-02-03
A PAGOSA simulation of a flyer plate impact which produces an elastic precursor wave is examined. The simulation is compared to an analytic theory for the Mie-Grüneisen equation of state and an elastic-perfectly-plastic strength model.
Elasticity of Flowing Soap films
Kim, Ildoo; Mandre, Shreyas
2016-11-01
The robustness of soap films and bubbles manifests their mechanical stability. The single most important factor underlying the mechanical stability of soap films is its elasticity. Non-destructive measurement of the elasticity in these films has been cumbersome, because of its flowing nature. Here we provide a convenient, reproducible, and non-destructive method for measuring the elasticity by generating and inspecting Marangoni waves. Our method is based on generating an oblique shock by inserting a thin cylindrical obstacle in the flowing film, and converting the measured the shock angle to elasticity. Using this method, we find a constant value for the elasticity of 22 dyne/cm in the commonly used range of film widths, thicknesses or flow rates, implying that the surface of the film is chemically saturated with soap molecules.
Forgács, Péter; Lukács, Árpád; Romańczukiewicz, Tomasz
2013-12-01
It is shown that in a large class of systems, plane waves act as tractor beams: i.e., an incident plane wave can exert a pulling force on the scatterer. The underlying physical mechanism for the pulling force is due to the sufficiently strong scattering of the incoming wave into another mode carrying more momentum, in which case excess momentum is created behind the scatterer. This tractor beam or negative radiation pressure (NRP) effect, is found to be generic in systems with multiple scattering channels. In a birefringent medium, electromagnetic plane waves incident on a thin plate exert NRP of the same order of magnitude as optical radiation pressure, while in artificial dielectrics (metamaterials), the magnitude of NRP can even be macroscopic. In two dimensions, we study various scattering situations on vortices, and NRP is shown to occur by the scattering of heavy baryons into light leptons off cosmic strings, and by neutron scattering off vortices in the XY model.
Directory of Open Access Journals (Sweden)
Linero Dorian
2011-05-01
Full Text Available
Este trabajo describe un modelo numérico implementado en el método de los elementos finitos (Hughes, 2000, el cual permite simular el comportamiento elástico del concreto reforzado con fibras cortas de dirección aleatoria. En estructuras hechas de dicho material cada punto está compuesto por fibras cortas de acero embebidas en una matriz de concreto simple. En el interior de un elemento finito el concreto reforzado se representa como un material ortótropo de dirección material aleatoria, basado en el modelo de fibras con diámetro despreciable (Dvorak y Bahei-el-Din, 1982 y la teoría de mezclas modificada para refuerzo de corta longitud (Oller, 2003. El análisis estadístico realizado consiste en: repetir la simulación numérica del problema cambiando la dirección de las fibras mediante una función aleatoria, construir la base de datos de muestreo a partir de los resultados obtenidos y medir la dispersión de estos últimos. A continuación, en este trabajo se estudia la sensibilidad del tamaño de los elementos finitos y del número de datos de muestreo en el cálculo de la energía total de deformación y se establecen algunos valores recomendables. Como ejemplo de aplicación se obtuvo la respuesta estructural promedio de una viga de concreto reforzado con diferentes cuantías de fibras cortas de acero, observando una dispersión mínima de los datos.
This work describes a numerical model of fibre reinforced concrete elastic behaviour implemented using the finite elements method (Hughes, 2000. In structures made of this material, each
O( d+1 , d+1) enhanced double field theory
Hohm, Olaf; Musaev, Edvard T.; Samtleben, Henning
2017-10-01
Double field theory yields a formulation of the low-energy effective action of bosonic string theory and half-maximal supergravities that is covariant under the T-duality group O( d, d) emerging on a torus T d . Upon reduction to three spacetime dimensions and dualisation of vector fields into scalars, the symmetry group is enhanced to O( d+1 , d+1). We construct an enhanced double field theory with internal coordinates in the adjoint representation of O( d + 1 , d + 1). Its section constraints admit two inequivalent solutions, encoding in particular the embedding of D = 6 chiral and non-chiral theories, respectively. As an application we define consistent generalized Scherk-Schwarz reductions using a novel notion of generalized parallelization. This allows us to prove the consistency of the truncations of D = 6, N=(1,1) and D = 6, N=(2,0) supergravity on {AdS}_3× S^3.
Developing 1D nanostructure arrays for future nanophotonics
Directory of Open Access Journals (Sweden)
Cooke DG
2006-01-01
Full Text Available AbstractThere is intense and growing interest in one-dimensional (1-D nanostructures from the perspective of their synthesis and unique properties, especially with respect to their excellent optical response and an ability to form heterostructures. This review discusses alternative approaches to preparation and organization of such structures, and their potential properties. In particular, molecular-scale printing is highlighted as a method for creating organized pre-cursor structure for locating nanowires, as well as vapor–liquid–solid (VLS templated growth using nano-channel alumina (NCA, and deposition of 1-D structures with glancing angle deposition (GLAD. As regards novel optical properties, we discuss as an example, finite size photonic crystal cavity structures formed from such nanostructure arrays possessing highQand small mode volume, and being ideal for developing future nanolasers.
Quantitative 1D saturation profiles on chalk by NMR
DEFF Research Database (Denmark)
Olsen, Dan; Topp, Simon; Stensgaard, Anders
1996-01-01
Quantitative one-dimensional saturation profiles showing the distribution of water and oil in chalk core samples are calculated from NMR measurements utilizing a 1D CSI spectroscopy pulse sequence. Saturation profiles may be acquired under conditions of fluid flow through the sample. Results reveal...... that strong saturation gradients exist in chalk core samples after core floods, due to capillary effects. The method is useful in analysis of corefloods, e.g., for determination of capillary pressure functions...
Plane waves in noncommutative fluids
Energy Technology Data Exchange (ETDEWEB)
Abdalla, M.C.B., E-mail: mabdalla@ift.unesp.br [Instituto de Física Teórica, UNESP, Universidade Estadual Paulista, Rua Dr. Bento Teobaldo Ferraz 271, Bloco 2, Barra-Funda, Caixa Postal 70532-2, 01156-970, São Paulo, SP (Brazil); Holender, L., E-mail: holender@ufrrj.br [Grupo de Física Teórica e Matemática Física, Departamento de Física, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Cx. Postal 23851, BR 465 Km 7, 23890-000 Seropédica, RJ (Brazil); Santos, M.A., E-mail: masantos@cce.ufes.br [Departamento de Física e Química, Universidade Federal do Espírito Santo (UFES), Avenida Fernando Ferarri S/N, Goiabeiras, 29060-900 Vitória, ES (Brazil); Vancea, I.V., E-mail: ionvancea@ufrrj.br [Grupo de Física Teórica e Matemática Física, Departamento de Física, Universidade Federal Rural do Rio de Janeiro (UFRRJ), Cx. Postal 23851, BR 465 Km 7, 23890-000 Seropédica, RJ (Brazil)
2013-08-01
We study the dynamics of the noncommutative fluid in the Snyder space perturbatively at the first order in powers of the noncommutative parameter. The linearized noncommutative fluid dynamics is described by a system of coupled linear partial differential equations in which the variables are the fluid density and the fluid potentials. We show that these equations admit a set of solutions that are monochromatic plane waves for the fluid density and two of the potentials and a linear function for the third potential. The energy–momentum tensor of the plane waves is calculated.
Development of 1D Liner Compression Code for IDL
Shimazu, Akihisa; Slough, John; Pancotti, Anthony
2015-11-01
A 1D liner compression code is developed to model liner implosion dynamics in the Inductively Driven Liner Experiment (IDL) where FRC plasmoid is compressed via inductively-driven metal liners. The driver circuit, magnetic field, joule heating, and liner dynamics calculations are performed at each time step in sequence to couple these effects in the code. To obtain more realistic magnetic field results for a given drive coil geometry, 2D and 3D effects are incorporated into the 1D field calculation through use of correction factor table lookup approach. Commercial low-frequency electromagnetic fields solver, ANSYS Maxwell 3D, is used to solve the magnetic field profile for static liner condition at various liner radius in order to derive correction factors for the 1D field calculation in the code. The liner dynamics results from the code is verified to be in good agreement with the results from commercial explicit dynamics solver, ANSYS Explicit Dynamics, and previous liner experiment. The developed code is used to optimize the capacitor bank and driver coil design for better energy transfer and coupling. FRC gain calculations are also performed using the liner compression data from the code for the conceptual design of the reactor sized system for fusion energy gains.
Enhancing Solar Cell Efficiencies through 1-D Nanostructures
Directory of Open Access Journals (Sweden)
Yu Kehan
2008-01-01
Full Text Available Abstract The current global energy problem can be attributed to insufficient fossil fuel supplies and excessive greenhouse gas emissions resulting from increasing fossil fuel consumption. The huge demand for clean energy potentially can be met by solar-to-electricity conversions. The large-scale use of solar energy is not occurring due to the high cost and inadequate efficiencies of existing solar cells. Nanostructured materials have offered new opportunities to design more efficient solar cells, particularly one-dimensional (1-D nanomaterials for enhancing solar cell efficiencies. These 1-D nanostructures, including nanotubes, nanowires, and nanorods, offer significant opportunities to improve efficiencies of solar cells by facilitating photon absorption, electron transport, and electron collection; however, tremendous challenges must be conquered before the large-scale commercialization of such cells. This review specifically focuses on the use of 1-D nanostructures for enhancing solar cell efficiencies. Other nanostructured solar cells or solar cells based on bulk materials are not covered in this review. Major topics addressed include dye-sensitized solar cells, quantum-dot-sensitized solar cells, and p-n junction solar cells.
On Elasticity Measurement in Cloud Computing
Wei Ai; Kenli Li; Shenglin Lan; Fan Zhang; Jing Mei; Keqin Li; Rajkumar Buyya
2016-01-01
Elasticity is the foundation of cloud performance and can be considered as a great advantage and a key benefit of cloud computing. However, there is no clear, concise, and formal definition of elasticity measurement, and thus no effective approach to elasticity quantification has been developed so far. Existing work on elasticity lack of solid and technical way of defining elasticity measurement and definitions of elasticity metrics have not been accurate enough to capture the essence of elas...
Becker, K.; Shapiro, S.; Stanchits, S.; Dresen, G.; Kaselow, A.; Vinciguerra, S.
2005-12-01
Elastic properties of rocks are sensitive to changes of the in-situ stress and damage state. In particular, seismic velocities are strongly affected by stress-induced formation and deformation of cracks or shear-enhanced pore collapse. The effect of stress on seismic velocities as a result of pore space deformation in isotropic rock at isostatic compression may be expressed by the equation: A+K*P-B*exp (-D*P) (1), where P=Pc-Pp is the effective pressure, the pure difference between confining pressure and pore pressure. The parameter A, K, B and D describe material constants determined using experimental data. The physical meaning of the parameters is given by Shapiro (2003, in Geophysics Vol.68(Nr.2)). Parameter D is related to the stress sensitivity of the rock. A similar relation was derived by Shapiro and Kaselow (2005, in Geophysics in press) for weak anisotropic rocks under arbitrary load. They describe the stress dependent anisotropy in terms of Thomson's (1986, in Geophysics, Vol. 51(Nr.10)) anisotropy parameters ɛ and γ as a function of stress in the case of an initially isotropic rock: ɛ ∝ E2-E3, γ ∝ E3-E2 (2) with Ei=exp (D*Pi). The exponential terms Ei are controlled by the effective stress components Pi. To test this relation, we have conducted a series of triaxial compression tests on dry samples of initially isotropic Etnean Basalt in a servo-controlled MTS loading frame equipped with a pressure cell. Confining pressure was 60, 40 and 20 MPa. Samples were 5 cm in diameter and 10 cm in length. Elastic anisotropy was induced by axial compression of the samples through opening and growth of microcracks predominantly oriented parallel to the sample axis. Ultrasonic P- and S- wave velocities were monitored parallel and normal to the sample axis by an array of 20 piezoceramic transducers glued to the surface. Preamplified full waveform signals were stored in two 12 channel transient recorders. According to equation 2 the anisotropy parameters are
Elastic plastic analysis of growing cracks
Energy Technology Data Exchange (ETDEWEB)
Rice, J R; Drugan, W J; Sham, T L
1979-05-01
The elastic--plastic stress and deformation fields at the tip of a crack which grows in an ideally plastic solid under plane strain, shows small scale yielding conditions. Results of an asymptotic analysis suggests the existence of a crack tip stress state similar to that of the classical Prandtl field, but containing a zone of elastic unloading between the centered fan region and the trailing constant stress plastic region. The near tip expression for the rate of opening displacement delta at distance r from the growing tip is found to have the form delta-. = ..cap alpha.. J-./sigma/sub o/ + ..beta..(sigma/sub o//E) a-. ln(R/r) but the presence of the elastic wedge causes ..beta.. to have the revised value of 5.08 (for Poisson ratio ..nu.. = 0.3); also, (a = crack length, sigma/sub o/ = yield strength, E = elastic modulus, and J denotes the far-field value), and (1-..nu../sup 2/)K/sup 2//E for the small scale yielding conditions considered. The parameters ..cap alpha.. and R cannot be determined from the asymptotic analysis, but comparisons with finite element solutions suggest that, for small amounts of growth, ..cap alpha.. is approximately the same for stationary and growing cracks, and R scales approximately with the size of the plastic zone, being about 15% to 30% larger. For large scale yielding, a similar form applies with possible variations in ..cap alpha.. and ..beta.., in cases which maintain triaxial constraint at the crack tip. In the fully yielded case R is expected to be proportional to the dimension of the uncracked ligament. Model crack growth criterion requiring a critical delta at some fixed r from the tip, is re-examined in light of the more accurate solution. Results suggest that the J versus ..delta..a relation describing growth is dependent on the extent of yielding. It is suggested that this dependency might be small for highly ductile materials, provided that a similar triaxial constraint is maintained in all cases.
DEFF Research Database (Denmark)
Rathkjen, Arne
A state of plane stress is illustrated by means of two families of curves, each family representing constant values of a derivative of Airy's stress function. The two families of curves form a map giving in the first place an overall picture of regions of high and low stress, and in the second pl...
Plane and parabolic solar panels
Sales, J. H. O.; Suzuki, A. T.
2009-01-01
We present a plane and parabolic collector that absorbs radiant energy and transforms it in heat. Therefore we have a panel to heat water. We study how to increment this capture of solar beams onto the panel in order to increase its efficiency in heating water.
Algebraic Methods in Plane Geometry
Indian Academy of Sciences (India)
Srimath
group, taxicab number, Carmi- chael number. Algebraic Methods in Plane Geometry. 2. Cubic Curves. Shailesh A Shirali. Shailesh Shirali heads a. Community Mathematics. Center at Rishi Valley. School (KFI). He has a ..... Ian Stewart and David Tall, Algebraic Number Theory and Fermat's Last. Theorem, A K Peters, 2002.
Zapp, Kai; Orús, Román
2017-06-01
The simulation of lattice gauge theories with tensor network (TN) methods is becoming increasingly fruitful. The vision is that such methods will, eventually, be used to simulate theories in (3 +1 ) dimensions in regimes difficult for other methods. So far, however, TN methods have mostly simulated lattice gauge theories in (1 +1 ) dimensions. The aim of this paper is to explore the simulation of quantum electrodynamics (QED) on infinite lattices with TNs, i.e., fermionic matter fields coupled to a U (1 ) gauge field, directly in the thermodynamic limit. With this idea in mind we first consider a gauge-invariant infinite density matrix renormalization group simulation of the Schwinger model—i.e., QED in (1 +1 ) d . After giving a precise description of the numerical method, we benchmark our simulations by computing the subtracted chiral condensate in the continuum, in good agreement with other approaches. Our simulations of the Schwinger model allow us to build intuition about how a simulation should proceed in (2 +1 ) dimensions. Based on this, we propose a variational ansatz using infinite projected entangled pair states (PEPS) to describe the ground state of (2 +1 ) d QED. The ansatz includes U (1 ) gauge symmetry at the level of the tensors, as well as fermionic (matter) and bosonic (gauge) degrees of freedom both at the physical and virtual levels. We argue that all the necessary ingredients for the simulation of (2 +1 ) d QED are, a priori, already in place, paving the way for future upcoming results.
Coupling of Nod1D and HOTCHANNEL: static case; Acoplamiento de Nod1D y HOTCHANNEL: caso estatico
Energy Technology Data Exchange (ETDEWEB)
Gomez T, A.M. [IPN-ESFM, 07738 Mexico D.F. (Mexico); Ovando C, R. [IIE-Gcia. de Energia Nuclear, Cuernavaca, Morelos (Mexico)]. e-mail: rovando@iie.org.mx
2003-07-01
In this work the joining of the programs Nod1D and HOTCHANNEL, developed in the National Polytechnic Institute (IPN) and in the Electrical Research Institute (IIE) respectively is described. The first one allows to study the neutronic of a nuclear reactor and the second one allows to carry out the analysis of hot channel of a Boiling Water Reactor (BWR). Nod1 D is a program that it solves by nodal methods type finite element those diffusion equations in multigroup, and it is the static part of Nod Kin that it solves the diffusion equation in their time dependent part. For another side HOTCHANNEL is based on a mathematical model constituted by four conservation equations (two of mass conservation, one of motion quantity and one of energy), which are solved applying one discretization in implicit finite differences. Both programs have been verified in independent form using diverse test problems. In this work the modifications that were necessary to carry out to both for obtaining a coupled program that it provides the axial distribution of the neutron flux, the power, the burnup and the void fraction, among others parameters as much as neutronic as thermal hydraulics are described. Those are also mentioned limitations, advantages and disadvantages of the final product to which has been designated Nod1 D-HotChn. Diverse results for the Cycle 1 of the Laguna Verde Unit 1 reactor of the Nucleo electric central comparing them with those obtained directly with the CoreMasterPresto code are provided. (Author)
Power spectral density of the heterogeneous fracture compliance from scattered elastic wavefields
Minato, S.; Ghose, R.
2014-01-01
Using the scattered elastic wavefield, a method to derive the power spectral density (PSD) of the heterogeneous compliance distribution, along the plane of a single fracture, is formulated. The method involves estimation of the stress field at the fracture depth from the scattered wavefield followed
Diffraction Plane Dependence of Micro Residual Stresses in Uniaxially Extended Carbon Steels
Directory of Open Access Journals (Sweden)
T. Hanabusa
2010-12-01
Full Text Available In the stress measurement using X-ray or neutron diffraction, an elastic anisotropy as well as a plastic anisotropy of crystal must be carefully considered. In the X-ray and neutron diffraction stress measurement for polycrystalline materials, a particular {hkl} plane is used in measuring lattice strains. The dependence of an X-ray elastic constant on a diffraction plane is a typical example caused by an elastic anisotropy of the crystal. The yield strength and the work hardening rate of a single crystal depend on a crystallographic direction of the crystal. The difference in the yield strength and the work hardening rate relating to the crystallographic direction develops different residual stresses measured on each {hkl} diffraction after plastic deformation of a polycrystalline material. The present paper describes the result of the neutron stress measurement on uniaxially extended low and middle carbon steels. A tri-axial residual stress state developed in the extended specimens was measured on different kind of {hkl} diffraction plane. The measurement on the {110}, {200} and {211} diffraction showed that residual stresses increased with increasing the plastic elongation and the residual stresses on {110} were compressive, {200} were tensile and those on {211} were the middle of the former two planes.
1-D blood flow modelling in a running human body.
Szabó, Viktor; Halász, Gábor
2017-07-01
In this paper an attempt was made to simulate blood flow in a mobile human arterial network, specifically, in a running human subject. In order to simulate the effect of motion, a previously published immobile 1-D model was modified by including an inertial force term into the momentum equation. To calculate inertial force, gait analysis was performed at different levels of speed. Our results show that motion has a significant effect on the amplitudes of the blood pressure and flow rate but the average values are not effected significantly.
Enhanced transmission of electromagnetic waves through 1D plasmonic crystals.
So, Jin-Kyu; Jung, Hoe-Cheon; Min, Sun-Hong; Jang, Kyu-Ha; Bak, Seung-Ho; Park, Gun-Sik
2010-09-13
Transmission of electromagnetic waves through thick perfect conducting slabs perforated by one-dimensional arrays of rectangular holes was studied experimentally in the microwave frequency range. The observed thickness-dependent transmission clearly exhibits the evanescent and propagating nature of the involved electromagnetic excitations on the considered structures, which are effective surface plasmons and localized waveguide resonances, respectively. The 1D crystals showing transmission based on localized resonances further manifests the frequency-dependent effective refractive index depending on the filling ratio of the holes and accompanies resonant guided wave propagation.
Astronomical optics and elasticity theory
Lemaitre, Gerard Rene
2008-01-01
Astronomical Optics and Elasticity Theory provides a very thorough and comprehensive account of what is known in this field. After an extensive introduction to optics and elasticity, the book discusses variable curvature and multimode deformable mirrors, as well as, in depth, active optics, its theory and applications. Further, optical design utilizing the Schmidt concept and various types of Schmidt correctors, as well as the elasticity theory of thin plates and shells are elaborated upon. Several active optics methods are developed for obtaining aberration corrected diffraction gratings. Further, a weakly conical shell theory of elasticity is elaborated for the aspherization of grazing incidence telescope mirrors. The very didactic and fairly easy-to-read presentation of the topic will enable PhD students and young researchers to actively participate in challenging astronomical optics and instrumentation projects.
Celestial mechanics of elastic bodies
Beig, Robert; Schmidt, Bernd G.
2006-01-01
We construct time independent configurations of two gravitating elastic bodies. These configurations either correspond to the two bodies moving in a circular orbit around their center of mass or strictly static configurations.
Uniqueness theorems in linear elasticity
Knops, Robin John
1971-01-01
The classical result for uniqueness in elasticity theory is due to Kirchhoff. It states that the standard mixed boundary value problem for a homogeneous isotropic linear elastic material in equilibrium and occupying a bounded three-dimensional region of space possesses at most one solution in the classical sense, provided the Lame and shear moduli, A and J1 respectively, obey the inequalities (3 A + 2 J1) > 0 and J1>O. In linear elastodynamics the analogous result, due to Neumann, is that the initial-mixed boundary value problem possesses at most one solution provided the elastic moduli satisfy the same set of inequalities as in Kirchhoffs theorem. Most standard textbooks on the linear theory of elasticity mention only these two classical criteria for uniqueness and neglect altogether the abundant literature which has appeared since the original publications of Kirchhoff. To remedy this deficiency it seems appropriate to attempt a coherent description ofthe various contributions made to the study of uniquenes...
Elastic Properties of Mantle Minerals
Duffy, T. S.; Stan, C. V.
2012-12-01
The most direct information about the interior structure of the Earth comes from seismic wave velocities. Interpretation of seismic data requires an understanding of how sound velocities and elastic properties of minerals vary with pressure, temperature, crystal structure, and composition as well as the role of anelasticity, melts, etc. More generally, elastic moduli are important for understanding many solid-state phenomena including mechanical stability, interatomic interactions, material strength, compressibility, and phase transition mechanisms. The database of mineral elasticity measurements has been growing rapidly in recent years. In this work, we report initial results of an ongoing survey of our current knowledge of mineral elasticity at both ambient conditions and high pressures and temperatures. The analysis is selective, emphasizing single crystal measurements but also incorporating polycrystalline measurements and volume compression data as appropriate. The goal is to synthesize our current understanding of mineral elasticity in terms of structure and composition, and to identify the major remaining needs for experimental and theoretical work. Clinopyroxenes (Cpx) provide an example of our approach. A wide range of clinopyroxene compositions are found geologically and Mg-, Ca-, and Na-rich clinopyroxenes are expected to be important components in the upper mantle. The single-crystal elastic properties of a number of endmember Cpx compositions have been measured and these exhibit a range of ~25% in shear velocity. Those with monovalent cations (spodumene, jadeite) in the M2 site exhibit the highest velocities while Fe-rich (hendenbergit, acmite) compositions have the lowest velocities. The effects on velocity due to a wide range of chemical substitutions can be defined, but there are important discrepancies and omissions in the database. New measurements of omphacites, intermediate diopside-hedenbergite compositions, aegerine/acmite, augite, etc. are
Sivak, David Alexander
DNA bending elasticity on length scales of tens of basepairs is of critical importance in numerous biological contexts. Even the simplest models of DNA bending admit of few simple analytic results, thus there is a need for numerical methods to calculate experimental observables, such as distance distributions, forces, FRET efficiencies, and timescales of particular large-scale motions. We have implemented and helped develop a coarse-grained representation of DNA and various other covalently-linked groups that allows simple calculation of such observables for varied experimental systems. The simple freely-jointed chain (FJC) model and extremely coarse resolution proved useful in understanding DNA threading through nanopores, identifying steric occlusion by other parts of the chain as a prime culprit for slower capture as distance to the pore decreased. Enhanced sampling techniques of a finer resolution discrete wormlike chain (WLC) model permitted calculation of cyclization rates for small chains and identified the ramifications of a thermodynamically-sound treatment of thermal melts. Adding treatment of double-stranded DNA's helical nature and single-stranded DNA provided a model system that helped demonstrate the importance of statistical fluctuations in even highly-stressed DNA mini-loops, and allowed us to verify that even these constructs show no evidence of excitation-induced softening. Additional incorporation of salt-sensitivity to the model allowed us to calculate forces and FRET efficiencies for such mini-loops and their uncircularized precursors, thereby furthering the understanding of the nature of IHF binding and bending of its recognition sequence. Adding large volume-excluding spheres linked to the ends of the dsDNA permits calculation of distance distributions and thus small-angle X-ray scattering, whereby we demonstrated the validity of the WLC in describing bending fluctuations in DNA chains as short as 42 bp. We also make important connections
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.
Consumer cohorts and demand elasticities
Geir Wæhler Gustavsen
2015-01-01
A mixed effects model is used to estimate intercepts, price and expenditure elasticities for vegetables, meat and fish in different cohorts. Results from Wald tests reveal that intercepts for fish are higher for older cohorts than for younger cohorts, and expenditure elasticities for meat are higher for older cohorts than for younger cohorts. The implication is that over time, when younger cohorts replace older cohorts, the total expenditure share for fish is likely to decrease contributing t...
Johnson, David A; Rose, William C; Edwards, Jonathan W; Naik, Ulhas P; Beris, Antony N
2011-03-15
A new application of 1D models of the human arterial network is proposed. We take advantage of the sensitivity of the models predictions for the pressure profiles within the main aorta to key model parameter values. We propose to use the patterns in the predicted differences from a base case as a way to infer to the most probable changes in the parameter values. We demonstrate this application using an impedance model that we have recently developed (Johnson, 2010). The input model parameters are all physiologically related, such as the geometric dimensions of large arteries, various blood properties, vessel elasticity, etc. and can therefore be patient specific. As a base case, nominal values from the literature are used. The necessary information to characterize the smaller arteries, arterioles, and capillaries is taken from a physical scaling model (West, 1999). Model predictions for the effective impedance of the human arterial system closely agree with experimental data available in the literature. The predictions for the pressure wave development along the main arteries are also found in qualitative agreement with previous published results. The model has been further validated against our own measured pressure data in the carotid and radial arteries, obtained from healthy individuals. Upon changes in the value of key model parameters, we show that the differences seen in the pressure profiles correspond to qualitatively different patterns for different parameters. This suggests the possibility of using the model in interpreting multiple pressure data of healthy/diseased individuals. Copyright © 2010 Elsevier Ltd. All rights reserved.
Free vibration of elastically supported thin cylinders including gyroscopic effects
CSIR Research Space (South Africa)
Loveday, PW
1998-10-29
Full Text Available stream_source_info loveday_1998.pdf.txt stream_content_type text/plain stream_size 30419 Content-Encoding ISO-8859-1 stream_name loveday_1998.pdf.txt Content-Type text/plain; charset=ISO-8859-1 D[R[ 747723*JSV 106...# or in_nite "rigid#[ 7 0887 Academic Press 0[ INTRODUCTION The vibration of thin elastic shells has been studied by many researchers[ The results of many of these studies have been summarised by Leissa 0 and Blevins 1 [ The literature contains numerous...
Achieving directional propagation of elastic waves via topology optimization.
He, Jingjie; Kang, Zhan
2018-01-01
This paper presents a study on topology optimization of novel material microstructural configurations to achieve directional elastic wave propagation through maximization of partial band gaps. A waveguide incorporating a periodic-microstructure material may exhibit different propagation properties for the plane elastic waves incident from different inlets. A topology optimization problem is formulated to enhance such a property with a gradient-based mathematical programming algorithm. For alleviating the issue of local optimum traps, the random morphology description functions (RMDFs) are introduced to generate random initial designs for the optimization process. The optimized designs finally converge to the orderly material distribution and numerical validation shows improved directional propagation property as expected. The utilization of linear two-dimension phononic crystal with efficient partial band gap is suitable for directional propagation with a broad frequency range. Copyright © 2017 Elsevier B.V. All rights reserved.
A Framework for Low-Communication 1-D FFT
Directory of Open Access Journals (Sweden)
Ping Tak Peter Tang
2013-01-01
Full Text Available In high-performance computing on distributed-memory systems, communication often represents a significant part of the overall execution time. The relative cost of communication will certainly continue to rise as compute-density growth follows the current technology and industry trends. Design of lower-communication alternatives to fundamental computational algorithms has become an important field of research. For distributed 1-D FFT, communication cost has hitherto remained high as all industry-standard implementations perform three all-to-all internode data exchanges (also called global transposes. These communication steps indeed dominate execution time. In this paper, we present a mathematical framework from which many single-all-to-all and easy-to-implement 1-D FFT algorithms can be derived. For large-scale problems, our implementation can be twice as fast as leading FFT libraries on state-of-the-art computer clusters. Moreover, our framework allows tradeoff between accuracy and performance, further boosting performance if reduced accuracy is acceptable.
Analytic study of 1D diffusive relativistic shock acceleration
Keshet, Uri
2017-10-01
Diffusive shock acceleration (DSA) by relativistic shocks is thought to generate the dN/dEpropto E-p spectra of charged particles in various astronomical relativistic flows. We show that for test particles in one dimension (1D), p-1=1-ln[γd(1+βd)]/ ln;[γu(1+βu)], where βu (βd) is the upstream (downstream) normalized velocity, and γ is the respective Lorentz factor. This analytically captures the main properties of relativistic DSA in higher dimensions, with no assumptions on the diffusion mechanism. Unlike 2D and 3D, here the spectrum is sensitive to the equation of state even in the ultra-relativistic limit, and (for a Jüttner-Synge equation of state) noticeably hardens with increasing 1<γu<57, before logarithmically converging back to p(γu→∞)=2. The 1D spectrum is sensitive to drifts, but only in the downstream, and not in the ultra-relativistic limit.
Entanglement and Nonlocality in Infinite 1D Systems.
Wang, Zizhu; Singh, Sukhwinder; Navascués, Miguel
2017-06-09
We consider the problem of detecting entanglement and nonlocality in one-dimensional (1D) infinite, translation-invariant (TI) systems when just near-neighbor information is available. This issue is deeper than one might think a priori, since, as we show, there exist instances of local separable states (classical boxes) which admit only entangled (nonclassical) TI extensions. We provide a simple characterization of the set of local states of multiseparable TI spin chains and construct a family of linear witnesses which can detect entanglement in infinite TI states from the nearest-neighbor reduced density matrix. Similarly, we prove that the set of classical TI boxes forms a polytope and devise a general procedure to generate all Bell inequalities which characterize it. Using an algorithm based on matrix product states, we show how some of them can be violated by distant parties conducting identical measurements on an infinite TI quantum state. All our results can be easily adapted to detect entanglement and nonlocality in large (finite, not TI) 1D condensed matter systems.
Numerical simulation of nonlinear dynamics of 1D pulsating detonations
Borisov, S. P.; Kudryavtsev, A. N.
2017-10-01
The development of 1D instability of a detonation wave is numerically simulated for a two-stage chemical model. The shock-fitting approach is employed to track the leading detonation front. In order to determine its motion, the equation for the acceleration of the shock wave derived from the Rankine-Hugoniot conditions and the characteristic relations is integrated along with the reactive Euler equations. The fifth-order WENO scheme is used, time stepping is performed with the four-stage Runge-Kutta-Gill method. It is shown that in a certain range of parameters of the problem (the degree of overdrive f, the dissociation energy Ed and the activation energy Ea ), the Zeldovich-Neumann-Döring stationary solution is unstable with respect to 1D disturbances. The evolution of disturbances at later nonlinear stages is studied. Nonlinear saturation of the growth of disturbances leads to the formation of a stable limit cycle. When changing the parameters of the problem, the period doubling bifurcation can occur leading to the appearance of pulsations with two different maxima of the amplitude.
Multigroup Synchronization in 1D-Bernoulli Chaotic Collaborative CDMA
Directory of Open Access Journals (Sweden)
Sumith Babu Suresh Babu
2017-01-01
Full Text Available Code-division multiple access (CDMA has played a remarkable role in the field of wireless communication systems, and its capacity and security requirements are still being addressed. Collaborative multiuser transmission and detection are a contemporary technique used in CDMA systems. The performance of these systems is governed by the proper accommodation of the users and by proper synchronization schemes. The major research concerns in the existing multiuser overloaded CDMA schemes are (i statistically uncorrelated PN sequences that cause multiple-access interference (MAI and (ii the security of the user’s data. In this paper, a novel grouped CDMA scheme, the 1D-Bernoulli chaotic collaborative CDMA (BCC-CDMA, is introduced, in which mutually orthogonal chaotic sequences spread the users’ data within a group. The synchronization of multiple groups in this scheme has been analyzed under MAI limited environments and the results are presented. This increases the user capacity and also provides sufficient security as a result of the correlation properties possessed by the chaotic codes. Multigroup synchronization is achieved using a 1D chaotic pilot sequence generated by the Bernoulli Map. The mathematical model of the proposed system is described and compared with the theoretical model of the synchronization in CDMA, the simulation results of which are presented.
Entanglement and Nonlocality in Infinite 1D Systems
Wang, Zizhu; Singh, Sukhwinder; Navascués, Miguel
2017-06-01
We consider the problem of detecting entanglement and nonlocality in one-dimensional (1D) infinite, translation-invariant (TI) systems when just near-neighbor information is available. This issue is deeper than one might think a priori, since, as we show, there exist instances of local separable states (classical boxes) which admit only entangled (nonclassical) TI extensions. We provide a simple characterization of the set of local states of multiseparable TI spin chains and construct a family of linear witnesses which can detect entanglement in infinite TI states from the nearest-neighbor reduced density matrix. Similarly, we prove that the set of classical TI boxes forms a polytope and devise a general procedure to generate all Bell inequalities which characterize it. Using an algorithm based on matrix product states, we show how some of them can be violated by distant parties conducting identical measurements on an infinite TI quantum state. All our results can be easily adapted to detect entanglement and nonlocality in large (finite, not TI) 1D condensed matter systems.
Hydrodynamics of planing monohull watercraft
Vorus, William S
2017-01-01
This book addresses the principles involved in the design and engineering of planing monohull power boats, with an emphasis on the theoretical fundamentals that readers need in order to be fully functional in marine design and engineering. Author William Vorus focuses on three topics: boat resistance, seaway response, and propulsion and explains the physical principles, mathematical details, and theoretical details that support physical understanding. In particular, he explains the approximations and simplifications in mathematics that lead to success in the applications of planing craft design engineering, and begins with the simplest configuration that embodies the basic physics. He leads readers, step-by-step, through the physical complications that occur, leading to a useful working knowledge of marine design and engineering. Included in the book are a wealth of examples that exemplify some of the most important naval architecture and marine engineering problems that challenge many of today’s engineers.
Conn Henry, Richard; Kilston, S.; Shostak, S.
2008-05-01
The strong advantages of SETI searches in the ecliptic plane have been pointed out by Kilston, Shostak, and Henry (2008). In our poster we show one possible history of civilizations in the galaxy, from birth, through galactic colonization, up to death - and even beyond. Should this scenario be correct, the pattern suggests that the best hope for success in SETI is exploration of the possibility that there are a few extremely ancient but non-colonizing civilizations; civilizations that, aeons ago, detected the existence of Earth (oxygen, and hence life) and of its Moon (stabilizing Earth's rotation) via observations of transits of the Sun (hence, ecliptic, which is stable over millions of years [Laskar et al. 2004]), and have been beaming voluminous information in our direction ever since, in their faint hope (now realized) that a technological "receiving” species would appear. To maintain such a targeted broadcast would be extremely cheap for an advanced civilization. A search of a swath centered on our ecliptic plane should easily find such civilizations, if they exist. We hope to carry out such a search, using the Allen Telescope Array. http://henry.pha.jhu.edu/poster.SETI.pdf References: Kilston, Steven; Shostak, Seth; & Henry, Richard Conn; "Who's Looking at You, Kid?: SETI Advantages near the Ecliptic Plane," AbSciCon 2008, April 14-17, Santa Clara, CA.; Laskar, J., et al., A&A 428, 261, 2004 This work was supported by Maryland Space Grant Consortium.
Problems in nonlinear elastic and elastic-plastic solids
Tilakraj, V R
2001-01-01
sub 0. We prove the corresponding sequence of minimisers of the mixed displacement-traction problem converges weakly to a minimiser of the pure displacement problem as the radius epsilon tends to zero. The third problem we consider is the expansion of a spherical cavity in a nonlinearly elastic-perfectly plastic solid under the action of an internal pressure P within the cavity. We calculate (i) the critical pressure required to produce unbounded expansion of the cavity in an infinite medium, and (ii) the critical pressure required to form a cavity from zero initial radius in a finite piece of material and show that both critical pressures are the same. We illustrate these results explicitly for a particular stored energy function. In this thesis we study variational problems in nonlinear elasticity and related problems for elastic-plastic solids. First, we consider a one-dimensional variational problem in nonlinear elasticity. We consider an elastic cylinder of length L subject to axially symmetric deformati...
On Characterization of Elasticity Parameters in Context of Measurement Errors
Slawinski, M. A.
2007-12-01
In this presentation, we discuss the one-to-one relation between the elasticity parameters and the traveltime and polarization of a propagating signal in the context of the measurement errors. The one-to-one relationship between seismic measurements and a model postulated in the realm of the constitutive equation of an elastic continuum provides the link between the observational and theoretical aspects of seismic tomography [1]. The existence of this link encourages us to develop methods of inferring the elasticity parameters from measurements. However, a consideration of required accuracy and the analysis of error sensitivity suggest that the pragmatic application of this one-to-one relationship might be a difficult task indeed [4]. There are eight symmetry classes of an elastic continuum whose properties are contained in the density-scaled elasticity tensor [6]. Given this tensor in an arbitrary coordinate system, we can identify to which symmetry class it belongs, as well as obtain the orientation of its symmetry axes and planes, and hence the elasticity parameters in a natural coordinate system [2]. To obtain the tensor to be studied, we consider either ray velocities and polarizations [1] or wavefront slownesses and polarizations [5]. For the former, we assume that the medium is homogeneous in order to invoke the straightness of rays to calculate ray velocity given the source and receiver position; for the latter, we assume that the medium is homogeneous in at least one direction in order to invoke the ray parameter. In spite of the limitations due to homogeneities, both approaches are sensitive to measurement errors, which are not negligible. In view of these observational concerns [4], we consider several weaker objectives based on the theoretical formulation. Rather than distinguishing among eight symmetry classes and obtaining the corresponding elasticity parameters, we might be able to distinguish among a few groups that contain several classes within
Elastic interaction of partially debonded circular inclusions. I. Theoretical solution
DEFF Research Database (Denmark)
Kushch, V.I.; Shmegera, S.V.; Mishnaevsky, Leon
2010-01-01
A complete solution has been obtained of the elasticity problem for a plane containing a finite array of partially debonded circular inclusions, regarded as the open-crack model of fibrous composite with interface damage. A general displacement solution of the single-inclusion problem has been...... derived by combining the complex potentials technique with the newly derived series expansions. This solution is valid for any non-uniform far load and is finite and exact in the case of polynomial far field. Applying the superposition principle expands this theory to the multiple inclusion problem...
A 3D Orthotropic Elastic Continuum Damage Material Model
Energy Technology Data Exchange (ETDEWEB)
English, Shawn Allen [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Brown, Arthur A. [Sandia National Lab. (SNL-CA), Livermore, CA (United States)
2013-08-01
A three dimensional orthotropic elastic constitutive model with continuum damage is implemented for polymer matrix composite lamina. Damage evolves based on a quadratic homogeneous function of thermodynamic forces in the orthotropic planes. A small strain formulation is used to assess damage. In order to account for large deformations, a Kirchhoff material formulation is implemented and coded for numerical simulation in Sandia’s Sierra Finite Element code suite. The theoretical formulation is described in detail. An example of material parameter determination is given and an example is presented.
Roles of TBC1D1 and TBC1D4 in insulin- and exercise-stimulated glucose transport of skeletal muscle
Cartee, Gregory D.
2014-01-01
This review focuses on two paralogue Rab GTPase activating proteins known as TBC1D1 Tre-2/BUB2/cdc 1 domain family (TBC1D) 1 and TBC1D4 (also called Akt Substrate of 160 kDa, AS160) and their roles in controlling skeletal muscle glucose transport in response to the independent and combined effects of insulin and exercise. Convincing evidence implicates Akt2-dependent TBC1D4 phosphorylation on T642 as a key part of the mechanism for insulin-stimulated glucose uptake by skeletal muscle. TBC1D1 ...
Mirzaali, M. J.; Hedayati, R.; Vena, P.; Vergani, L.; Strano, M.; Zadpoor, A. A.
2017-07-01
The elastic properties of mechanical metamaterials are direct functions of their topological designs. Rational design approaches based on computational models could, therefore, be used to devise topological designs that result in the desired properties. It is of particular importance to independently tailor the elastic modulus and Poisson's ratio of metamaterials. Here, we present patterned randomness as a strategy for independent tailoring of both properties. Soft mechanical metamaterials incorporating various types of patterned randomness were fabricated using an indirect additive manufacturing technique and mechanically tested. Computational models were also developed to predict the topology-property relationship in a wide range of proposed topologies. The results of this study show that patterned randomness allows for independent tailoring of the elastic properties and covering a broad area of the elastic modulus-Poisson's ratio plane. The uniform and homogenous topologies constitute the boundaries of the covered area, while topological designs with patterned randomness fill the enclosed area.
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......A computational method for dealing with higher order boundary conditions on moving elastic-plastic boundaries in strain gradient plasticity is proposed. The basic idea is to skip the notion of a purely elastic regime, and instead introduce a pseudo-elastic regime, where plastic deformations......, 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...
Connected components of irreducible maps and 1D quantum phases
Energy Technology Data Exchange (ETDEWEB)
Szehr, Oleg, E-mail: oleg.szehr@posteo.de [Centre for Quantum Information, University of Cambridge, Cambridge CB3 0WA (United Kingdom); Wolf, Michael M., E-mail: wolf@ma.tum.de [Zentrum Mathematik, Technische Universität München, 85748 Garching (Germany)
2016-08-15
We investigate elementary topological properties of sets of completely positive (CP) maps that arise in quantum Perron-Frobenius theory. We prove that the set of primitive CP maps of fixed Kraus rank is path-connected and we provide a complete classification of the connected components of irreducible CP maps at given Kraus rank and fixed peripheral spectrum in terms of a multiplicity index. These findings are then applied to analyse 1D quantum phases by studying equivalence classes of translational invariant matrix product states that correspond to the connected components of the respective CP maps. Our results extend the previously obtained picture in that they do not require blocking of physical sites, they lead to analytic paths, and they allow us to decompose into ergodic components and to study the breaking of translational symmetry.
Axial turbomachine modelling with a 1D axisymmetric approach
Energy Technology Data Exchange (ETDEWEB)
Tauveron, Nicolas [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, 17 rue des Martyrs, 38100 Grenoble (France)]. E-mail: nicolas.tauveron@cea.fr; Saez, Manuel [Commissariat a l' Energie Atomique, Direction de l' Energie Nucleaire, 17 rue des Martyrs, 38100 Grenoble (France)]. E-mail: manuel.saez@cea.fr; Ferrand, Pascal [Laboratoire de Mecanique des Fluides et d' Acoustique, Ecole Centrale de Lyon, 36 avenue de Collongue, 69134 Ecully Cedex (France)]. E-mail: pascal.ferrand@ec-lyon.fr; Leboeuf, Francis [Laboratoire de Mecanique des Fluides et d' Acoustique, Ecole Centrale de Lyon, 36 avenue de Collongue, 69134 Ecully Cedex (France)]. E-mail: francis.leboeuf@ec-lyon.fr
2007-09-15
This work concerns the design and safety analysis of direct cycle gas cooled reactor. The estimation of compressor and turbine performances in transient operations is of high importance for the designer. The first goal of this study is to provide a description of compressor behaviour in unstable conditions with a better understanding than the models based on performance maps ('traditional' 0D approach). A supplementary objective is to provide a coherent description of the turbine behaviour. The turbomachine modelling approach consists in the solution of 1D axisymmetric Navier-Stokes equations on an axial grid inside the turbomachine: mass, axial momentum, circumferential momentum and total-enthalpy balances are written. Blade forces are taken into account by using compressor or turbine blade cascade steady correlations. A particular effort has been developed to generate or test correlations in low mass flow and negative mass flow regimes, based on experimental data. The model is tested on open literature cases of the gas turbine aircraft community. For compressor and turbine, steady situations are fairly described, especially for medium and high mass flow rate. The dynamic behaviour of compressor is also quite well described, even in unstable operation (surge): qualitative tendencies (role of plenum volume and role of throttle) and some quantitative characteristics (frequency) are in a good agreement with experimental data. The application to transient simulations of gas cooled nuclear reactors is concentrated on the hypothetical 10 in. break accident. The results point out the importance of the location of the pipe rupture in a hypothetical break event. In some detailed cases, compressor surge and back flow through the circuit can occur. In order to be used in a design phase, a simplified model of surge has also been developed. This simplified model is applied to the gas fast reactor (GFR) and compared quite favourably with 1D axisymmetric simulation
DEFF Research Database (Denmark)
Treebak, Jonas Thue; Pehmøller, Christian; Kristensen, Jonas Møller
2014-01-01
We investigated the phosphorylation signatures of two Rab GTPase activating proteins TBC1D1 and TBC1D4 in human skeletal muscle in response to physical exercise and physiological insulin levels induced by a carbohydrate rich meal using a paired experimental design. Eight healthy male volunteers......; TBC1D4: S588, S751), and that responded to both insulin and exercise (TBC1D1: T596; TBC1D4: S341, T642, S704). In the insulin stimulated leg, Akt phosphorylation on both T308 and S473 correlated significantly with multiple sites on both TBC1D1 (T596) and TBC1D4 (S318, S341, S704). Interestingly......, in the exercised leg in the fasted state TBC1D1 phosphorylation (S237, T596) correlated significantly with the activity of the α2β2γ3 AMPK trimer, whereas TBC1D4 phosphorylation (S341, S704) correlated with the activity of the α2β2γ1 AMPK trimer. Our data show differential phosphorylation of TBC1D1 and TBC1D4...
Some Considerations Regarding Plane to Plane Parallelism Error Effects in Robotic Systems
Directory of Open Access Journals (Sweden)
Stelian Alaci
2015-06-01
Full Text Available The paper shows that by imposing the parallelism constraint between the measured plane and the reference plane, the position of the current plane is not univocal specified and is impossible to specify the way to attain the parallelism errors imposed by accuracy constrains. The parameters involved in the calculus of plane to plane parallelism error can be used to set univocal the relative position between the two planes.
Energy Technology Data Exchange (ETDEWEB)
Caballero, J.A. [Univ. de Sevilla (Spain). Dept. de Fisica Atomica, Molecular y Nucl.]|[Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 123, Madrid 28006 (Spain); Donnelly, T.W. [Centre for Theoretical Physics, Laboratory for Nuclear Science and Dept. of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139-4307 (United States); Moya de Guerra, E. [Instituto de Estructura de la Materia, Consejo Superior de Investigaciones Cientificas, Serrano 123, Madrid 28006 (Spain); Udias, J.M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, Avda. Complutense s/n, Madrid 28040 (Spain)
1998-03-23
The issue of factorization within the context of coincidence quasi-elastic electron scattering is revisited. Using a relativistic formalism for the entire reaction mechanism and restricting ourselves to the case of plane waves for the outgoing proton, we discuss the role of the negative-energy components of the bound nucleon wave function. (orig.). 30 refs.
SNAP Satellite Focal Plane Development
Energy Technology Data Exchange (ETDEWEB)
Bebek, C.; Akerlof, C.; Aldering, G.; Amanullah, R.; Astier, P.; Baltay, C.; Barrelet, E.; Basa, S.; Bercovitz, J.; Bergstrom, L.; Berstein, G.P.; Bester, M.; Bohlin, R.; Bonissent, A.; Bower, C.; Campbell, M.; Carithers, W.; Commins, E.; Day, C.; Deustua, S.; DiGennaro, R.; Ealet, A.; Ellis, R.; Emmett, W.; Eriksson, M.; Fouchez,D.; Fruchter, A.; Genat, J-F.; Goldhaber, G.; Goobar, A.; Groom, D.; Heetderks, H.; Holland, S.; Huterer, D.; Johnson, W.; Kadel, R.; Karcher,A.; Kim, A.; Kolbe, W.; Lafever, R.; Lamoureaux, J.; Lampton, M.; Lefevre, O.; Levi, M.; Levin, D.; Linder, E.; Loken, S.; Malina, R.; Mazure, A.; McKay, T.; McKee, S.; Miquel, R.; Morgan, N.; Mortsell, E.; Mostek, N.; Mufson, S.; Musser, J.; Roe, N.; Nugent, P.; Oluseyi, H.; Pain, R.; Palaio, N.; Pankow, D.; Perlmutter, S.; Prieto, E.; Rabinowitz,D.; Refregier, A.; Rhodes, J.; Schubnell, M.; Sholl, M.; Smadja, G.; Smith, R.; Smoot, G.; Snyder, J.; Spadafora, A.; Szymkowiak, A.; Tarle,G.; Taylor, K.; Tilquin, A.; Tomasch, A.; Vincent, D.; von der Lippe, H.; Walder, J-P.; Wang, G.
2003-07-07
The proposed SuperNova/Acceleration Probe (SNAP) mission will have a two-meter class telescope delivering diffraction-limited images to an instrumented 0.7 square degree field in the visible and near-infrared wavelength regime. The requirements for the instrument suite and the present configuration of the focal plane concept are presented. A two year R&D phase, largely supported by the Department of Energy, is just beginning. We describe the development activities that are taking place to advance our preparedness for mission proposal in the areas of detectors and electronics.
Combinatorial geometry in the plane
Hadwiger, Hugo; Klee, Victor
2014-01-01
Geared toward advanced undergraduates familiar with analysis and college geometry, this concise book discusses theorems on topics restricted to the plane such as convexity, coverings, and graphs. In addition to helping students cultivate rigorous thought, the text encourages the development of mathematical intuition and clarifies the nature of mathematical research.The two-part treatment begins with specific topics including integral distances, covering problems, point set geometry and convexity, simple paradoxes involving point sets, and pure combinatorics, among other subjects. The second pa
Contact Cohomology of the Projective Plane
Ernström, Lars; Kennedy, Gary
1997-01-01
We construct an associative ring which is a deformation of the quantum cohomology ring of the projective plane. Just as the quantum cohomology encodes the incidence characteristic numbers of rational plane curves, the contact cohomology encodes the tangency characteristic numbers.
Effects of the air sac thickness on ventilation by a 1D model of an avian respiratory system.
Urushikubo, Akira; Nakamura, Masanori; Hirahara, Hiroyuki
2013-01-01
Airflow in an avian respiratory system was simulated to study why birds affected with airsacculitis have respiratory distress. The airflow in the avian lung was modeled with a 1D electrical circuit and simulated for investigating what effect an increase in wall thickness of air sacs caused by airsacculitis has on flow in lung. The results demonstrated that thickening of the air sac wall caused anti-synchronization between an elastic recoiling force of the air sac walls and an intra-pleural pressure, bringing difficulties in expansion of air sacs to draw in airs during an inspiration period and thereby decreasing air to be pumped out during an expiration period. This was reflected in a decrease in air flow volume in parabronchi where gas exchange takes place. Therefore, it was concluded that airsacculitis causes imbalance in air flow dynamics in the avian lung and thus impairs breathing ability of birds.
Cant of Posterior Occlusal Plane in Class II Division 1 Patients - A Comparative Cephalometric Study
Directory of Open Access Journals (Sweden)
Rashmi Bhat
2010-01-01
& angular measurements. Statistical analysis was performed by Pearson product - moment correlation & student′s unpaired t- test. This study led us to the conclusion that while treating skeletalclass II division 1 malocclusion with a steep cant in the posterior occlusal plane,control of the vertical dimension of the posterior teeth is extremely important & it is recommended that class II elastics should be used as sparingly as possible.
Elastic actuation for legged locomotion
Cao, Chongjing; Conn, Andrew
2017-04-01
The inherent elasticity of dielectric elastomer actuators (DEAs) gives this technology great potential in energy efficient locomotion applications. In this work, a modular double cone DEA is developed with reduced manufacturing and maintenance time costs. This actuator can lift 45 g of mass (5 times its own weight) while producing a stroke of 10.4 mm (23.6% its height). The contribution of the elastic energy stored in antagonistic DEA membranes to the mechanical work output is experimentally investigated by adding delay into the DEA driving voltage. Increasing the delay time in actuation voltage and hence reducing the duty cycle is found to increase the amount of elastic energy being recovered but an upper limit is also noticed. The DEA is then applied to a three-segment leg that is able to move up and down by 17.9 mm (9% its initial height), which demonstrates the feasibility of utilizing this DEA design in legged locomotion.
GMPLS control plane extensions in support of flex-grid enabled elastic optical networks
DEFF Research Database (Denmark)
Turus, Ioan; Fagertun, Anna Manolova; Dittmann, Lars
2013-01-01
of generalized labels format and enable enhancements for the wavelength selection procedures. OSPF-TE enables the creation of spectrum databases based on novel LSA sub-TLV attributes capable of advertising spectrum status. Based on the implemented extensions, we propose and evaluate advanced distributed spectrum...... allocation schemes and strategies for dynamic routing algorithms in support of flex-grid optical networks....
The characteristic numbers of quartic plane curves
Vakil, Ravi
1998-01-01
The characteristic numbers of smooth plane quartics are computed using intersection theory on a component of the moduli space of stable maps. This completes the verification of Zeuthen's prediction of characteristic numbers of smooth plane curves. A short sketch of a computation of the characteristic numbers of plane cubics is also given as an illustration.
Barrier distributions from elastic scattering
Energy Technology Data Exchange (ETDEWEB)
Rowley, N. [Manchester Univ. (United Kingdom). Dept. of Physics]|[Surrey Univ., Guildford (United Kingdom). Dept. of Physics; Timmers, H.; Leigh, J.R.; Masgupta, M.; Hinde, D.J.; Mein, J.C.; Morton, C.R.; Newton, J.O. [Australian National Univ., Canberra, ACT (Australia). Dept. of Nuclear Physics
1996-01-01
A new representation of the distribution of potential barriers present in heavy ion reactions is defined in terms of the elastic scattering excitation function. Its validity is demonstrated for the systems {sup 16}0 + {sup 144,} {sup 154}Sm, {sup 186}W, {sup 208}Pb, for which precise measurements have been made. Compared with fusion barrier distributions, which show structures characteristic of collective inelastic couplings, the elastic distributions are less detailed. This appears to be due to couplings to weaker direct reaction channels. 20 refs., 3 figs.
Li, Huimin; Liu, Lin; Li, Hai-Bing; Song, Wei-Li; Bian, Xing-Ming; Zhao, Quan-Liang; Chen, Mingji; Yuan, Xujin; Chen, Haosen; Fang, Daining
2017-04-01
Since carbon-based structures of various dimensions, including one-dimensional (1D) carbon nanotubes, two-dimensional (2D) graphene and three-dimensional (3D) carbon foams, have attracted significant attention as microwave absorption fillers, we present an exceptional hetero-junction filler with a 1D-2D-1D feature, achieved by manipulating 2D graphene into 1D carbon fibers in the fiber-extruding process under the electric field. The as-fabricated 1D-2D-1D structural fillers exhibited much-improved dielectric properties and promoted microwave absorption performance in their composites, which is linked to the establishment of enhanced polarization capability, the generation of increased electric loss pathway and the creation of more favorable electromagnetic energy consumption conditions. The results suggest that employing 2D graphene in the 1D-2D-1D nanostructures played the critical role in tuning the electromagnetic response ability, because of its intrinsic electric advantages and dimensional features. To broaden the effective absorption bandwidth, periodic pattern-absorbing structures were designed, which showed combined absorption advantages for various thicknesses. Our strategy for fabricating 1D-2D-1D structural fillers illuminates a universal approach for manipulating dimensions and structures in the nanotechnology.
bessel functions for axisymmetric elasticity problems of the elastic
African Journals Online (AJOL)
HOD
homogeneous, isotropic, linear elastic half-space could be obtained by integration over the loaded region (area) with the point load solution considered as the Green function [1]. 1.1 Bessel Functions and Axisymmetric Problems. The Bessel's equations are commonly encountered in partial differential equations in bodies ...
Roles of TBC1D1 and TBC1D4 in insulin- and exercise-stimulated glucose transport of skeletal muscle
Cartee, Gregory D.
2014-01-01
This review focuses on two paralogue Rab GTPase activating proteins known as TBC1D1 Tre-2/BUB2/cdc 1 domain family (TBC1D) 1 and TBC1D4 (also called Akt Substrate of 160 kDa, AS160) and their roles in controlling skeletal muscle glucose transport in response to the independent and combined effects of insulin and exercise. Convincing evidence implicates Akt2-dependent TBC1D4 phosphorylation on T642 as a key part of the mechanism for insulin-stimulated glucose uptake by skeletal muscle. TBC1D1 phosphorylation on several insulin-responsive sites (including T596, a site corresponding to T642 in TBC1D4) does not appear to be essential for in vivo insulin-stimulated glucose uptake by skeletal muscle. In vivo exercise or ex vivo contraction of muscle result in greater TBC1D1 phosphorylation on S237 that is likely to be secondary to increased AMP-activated protein kinase activity and potentially important for contraction-stimulated glucose uptake. Several studies that evaluated both normal and insulin-resistant skeletal muscle stimulated with a physiological insulin concentration after a single exercise session found that greater post-exercise insulin-stimulated glucose uptake was accompanied by greater TBC1D4 phosphorylation on several sites. In contrast, enhanced post-exercise insulin sensitivity was not accompanied by greater insulin-stimulated TBC1D1 phosphorylation. The mechanism for greater TBC1D4 phosphorylation in insulin-stimulated muscles after acute exercise is uncertain, and a causal link between enhanced TBC1D4 phosphorylation and increased post-exercise insulin sensitivity has yet to be established. In summary, TBC1D1 and TBC1D4 have important, but distinct roles in regulating muscle glucose transport in response to insulin and exercise. PMID:25280670
Theoretical prediction of structural and elastic behavior of AlRu under pressure: A FP-LAPW study
Jain, Ekta; Pagare, Gitanjali; Devi, Hansa; Sanyal, S. P.
2015-06-01
Using full potential linearized augmented plane wave (FP-LAPW) method, the structural and elastic properties of AlRu intermetallic compound have been determined within the framework of density functional theory (DFT). The exchange correlation potential is used for generalized gradient approximations in the scheme of Perdew-Burke-Ernzerhof (GGA-PBE), Wu-Cohen (GGA-WC) and Perdew et. al. (GGA-PBEsol). Furthermore we have analyzed the trend of elastic constants (C11, C12 and C44) and elastic moduli (B, G and E) under variable pressure.
Silva, Luís Carlos; Milani, Gabriele; Lourenço, Paulo B.
2017-11-01
Two finite element homogenized-based strategies are presented for the out-of-plane behaviour characterization of an English bond masonry wall. A finite element micro-modelling approach using Cauchy stresses and first order movements are assumed for both strategies. The material nonlinearity is lumped on joints interfaces and bricks are considered elastic. Nevertheless, the first model is based on a Plane-stress assumption, in which the out-of-plane quantities are derived through on-thickness wall integration considering a Kirchhoff-plate theory. The second model is a tridimensional one, in which the homogenized out-of-plane quantities can be directly derived after solving the boundary value problem. The comparison is conducted by assessing the obtained out-of-plane bending- and torsion-curvature diagrams. A good agreement is found for the present study case.
Electrodeposition of photoactive 1D gallium selenide quantum dots
Energy Technology Data Exchange (ETDEWEB)
Gujar, T.P. [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: gujar_tp@yahoo.com; Shinde, V.R. [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of); Park, Jong-Won [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of); The Industrial Chemistry, University of Sang-Myung, Seoul 130-650 (Korea, Republic of); Lee, Hyun Kyung [Industrial Chemistry, University of Sang-Myung, Seoul 130-650 (Korea, Republic of); Jung, Kwang-Deog [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of); Joo, Oh-Shim [Clean Energy Research Center, Korea Institute of Science and Technology, Cheongryang, Seoul 130-650 (Korea, Republic of)], E-mail: joocat@kist.re.kr
2008-12-30
One-dimensional (1D) quantum dots of gallium selenide have been obtained by cathodic electrodeposition onto the tin doped indium oxide (ITO) glass substrates from aqueous acidic solutions at room temperature. Characterizations of the as-deposited films by energy dispersive X-ray (EDX) spectroscopy confirm a selenium rich chemistry, X-ray diffraction (XRD) shows that mixture of phases like GaSe/Ga{sub 2}Se{sub 3}, and optical spectroscopy shows a direct optical band gap of 2.85 eV with intermediate transition energy at 1.9 eV. From transmission electron microscopy (TEM), the films show the one-dimensional quantum dots chains in grains. Scanning electron microscopy (SEM) images indicate dimorphous placement of nanoparticles. The elementals surface analysis of the core-shell nanoparticles determined by X-ray photoelectron spectroscopy (XPS) supported the EDX results and confirmed the chemical nature of the material. The photoelectrochemical (PEC) studies of gallium selenide films were carried out and the nanocrystalline gallium selenide films were found to be photoactive in aqueous sodium thiosulphate solution.
Effective theory of black holes in the 1/D expansion
Energy Technology Data Exchange (ETDEWEB)
Emparan, Roberto [Institució Catalana de Recerca i Estudis Avançats (ICREA),Passeig Lluís Companys 23, E-08010 Barcelona (Spain); Departament de Física Fonamental, Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès 1, E-08028 Barcelona (Spain); Shiromizu, Tetsuya [Department of Mathematics, Nagoya University,Nagoya 464-8602 (Japan); Kobayashi-Maskawa Institute, Nagoya University,Nagoya 464-8602 (Japan); Suzuki, Ryotaku [Department of Physics, Osaka City University,Osaka 558-8585 (Japan); Tanabe, Kentaro [Theory Center, Institute of Particles and Nuclear Studies, KEK,Tsukuba, Ibaraki, 305-0801 (Japan); Tanaka, Takahiro [Department of Physics, Kyoto University,Kyoto, 606-8502 (Japan); Yukawa Institute for Theoretical Physics, Kyoto University,Kyoto, 606-8502 (Japan)
2015-06-23
The gravitational field of a black hole is strongly localized near its horizon when the number of dimensions D is very large. In this limit, we can effectively replace the black hole with a surface in a background geometry (e.g. Minkowski or Anti-deSitter space). The Einstein equations determine the effective equations that this ‘black hole surface’ (or membrane) must satisfy. We obtain them up to next-to-leading order in 1/D for static black holes of the Einstein-(A)dS theory. To leading order, and also to next order in Minkowski backgrounds, the equations of the effective theory are the same as soap-film equations, possibly up to a redshift factor. In particular, the Schwarzschild black hole is recovered as a spherical soap bubble. Less trivially, we find solutions for ‘black droplets’, i.e. black holes localized at the boundary of AdS, and for non-uniform black strings.
Cellular reprogramming dynamics follow a simple 1D reaction coordinate
Teja Pusuluri, Sai; Lang, Alex H.; Mehta, Pankaj; Castillo, Horacio E.
2018-01-01
Cellular reprogramming, the conversion of one cell type to another, induces global changes in gene expression involving thousands of genes, and understanding how cells globally alter their gene expression profile during reprogramming is an ongoing problem. Here we reanalyze time-course data on cellular reprogramming from differentiated cell types to induced pluripotent stem cells (iPSCs) and show that gene expression dynamics during reprogramming follow a simple 1D reaction coordinate. This reaction coordinate is independent of both the time it takes to reach the iPSC state as well as the details of the experimental protocol used. Using Monte-Carlo simulations, we show that such a reaction coordinate emerges from epigenetic landscape models where cellular reprogramming is viewed as a ‘barrier-crossing’ process between cell fates. Overall, our analysis and model suggest that gene expression dynamics during reprogramming follow a canonical trajectory consistent with the idea of an ‘optimal path’ in gene expression space for reprogramming.
3-D Whole-Core Transport Calculation with 3D/2D Rotational Plane Slicing Method
Energy Technology Data Exchange (ETDEWEB)
Yoo, Han Jong; Cho, Nam Zin [Korea Advanced Institute of Science and Technology, Daejeon (Korea, Republic of)
2014-10-15
Use of the method of characteristics (MOC) is very popular due to its capability of heterogeneous geometry treatment and widely used for 2-D core calculation, but direct extension of MOC to 3-D core is not so attractive due to huge calculational cost. 2-D/1-D fusion method was very successful for 3-D calculation of current generation reactor types (highly heterogeneous in radial direction but piece-wise homogeneous in axial direction). In this paper, 2-D MOC concept is extended to 3-D core calculation with little modification of an existing 2-D MOC code. The key idea is to suppose 3-D geometry as a set of many 2-D planes like a phone-directory book. Dividing 3-D structure into a large number of 2-D planes and solving each plane with a simple 2-D SN transport method would give the solution of a 3-D structure. This method was developed independently at KAIST but it is found that this concept is similar with that of 'plane tracing' in the MCCG-3D code. The method developed was tested on the 3-D C5G7 OECD/NEA benchmark problem and compared with the 2-D/1-D fusion method. Results show that the proposed method is worth investigating further. A new approach to 3-D whole-core transport calculation is described and tested. By slicing 3-D structure along characteristic planes and solving each 2-D plane problem, we can get 3-D solution. The numerical test results indicate that the new method is comparable with the 2D/1D fusion method and outperforms other existing methods. But more fair comparison should be done in similar discretization level.
Interaction of acoustic beam with elastic structures
Zhang, Han
This thesis describes experiments and calculations performed on the interaction of acoustic beams in water and air with planar and cylindrical elastic structures. Ultrasonic reflection measurements have been used to elucidate the phenomena of guided wave generation and reradiation by selecting beam incidence at, or near, phase-matching conditions. Under these circumstances reasonant mode conversion of accoustic wave to guided wave mode energy can occur. This interaction has been studied in rubber-coated steel, aluminum, plexiglas, and graphite-epoxy composite. The acoustic coupling media used in these experiments has been either water or air. Some theoretical modeling has also been undertaken to explain these results. The calculations performed here exploit an efficient analytical tool that simplifies the construction of finite acoustic beams. The method relies on the interesting mathematical fact that displacing a real point source into the couplex plane, converts the source into a quasi Gaussian beam. The free-space Green's function, which satisfies the inhomogeneous Helmholtz equation, is converted to a complex Green's function that describes the interaction of two beams, one from the source and the other at the observation point. The interaction with elastic structures is treated by spectral decomposition of the incident and reflected beams weighted by the plane wave reflection or transmission coefficient. The resulting spectral integral is evaluated either asymptotically along a steepest descent path, keeping track of the reflection/transmission coefficient pole contributions or numerically. In the first problem the interaction of acoustic beams with steel layered cylindrical shells is studied. The difficulty introduced by the high damping in the rubber is resolved and its influence on the signal is analyzed. The bond rigidity between the rubber and steel are accounted for in the model calculation by the so-called spring model. It is found that disbonds in the
Thomas, Siby; Ajith, K. M.; Valsakumar, M. C.
2017-11-01
This work intents to put forth the results of a classical molecular dynamics study to investigate the temperature dependent elastic constants of monolayer hexagonal boron nitride (h-BN) between 100 and 1000 K for the first time using strain fluctuation method. The temperature dependence of out-of-plane fluctuations (ripples) is quantified and is explained using continuum theory of membranes. At low temperatures, negative in-plane thermal expansion is observed and at high temperatures, a transition to positive thermal expansion has been observed due to the presence of thermally excited ripples. The decrease of Young's modulus, bulk modulus, shear modulus and Poisson's ratio with increase in temperature has been analyzed. The thermal rippling in h-BN leads to strong anharmonic behaviour that causes large deviation from the isotropic elasticity. A detailed study shows that the strong thermal rippling in large systems is also responsible for the softening of elastic constants in h-BN. From the determined values of elastic constants and elastic moduli, it has been elucidated that 2D h-BN sheets meet the Born's mechanical stability criterion in the investigated temperature range. The variation of longitudinal and shear velocities with temperature is also calculated from the computed values of elastic constants and elastic moduli.
An introduction to finite projective planes
Albert, Abraham Adrian
2015-01-01
Geared toward both beginning and advanced undergraduate and graduate students, this self-contained treatment offers an elementary approach to finite projective planes. Following a review of the basics of projective geometry, the text examines finite planes, field planes, and coordinates in an arbitrary plane. Additional topics include central collineations and the little Desargues' property, the fundamental theorem, and examples of finite non-Desarguesian planes.Virtually no knowledge or sophistication on the part of the student is assumed, and every algebraic system that arises is defined and
BESSEL FUNCTIONS FOR AXISYMMETRIC ELASTICITY ...
African Journals Online (AJOL)
The potential functions are then made to satisfy the governing field equations and the associated boundary conditions for the particular problem of a point load at the origin of the semi-infinite linear elastic isotropic soil mass. The unknown parameters of the function are thus determined and used to find the stresses, strains ...
Duration of an Elastic Collision
de Izarra, Charles
2012-01-01
With a pedagogical goal, this paper deals with a study of the duration of an elastic collision of an inflatable spherical ball on a planar surface suitable for undergraduate studies. First, the force generated by the deformed spherical ball is obtained under assumptions that are discussed. The study of the motion of the spherical ball colliding…
Kinematic support using elastic elements
Geirsson, Arni; Debra, Daniel B.
1988-01-01
The design of kinematic supports using elastic elements is reviewed. The two standard methods (cone, Vee and flat and three Vees) are presented and a design example involving a machine tool metrology bench is given. Design goals included thousandfold strain attenuation in the bench relative to the base when the base strains due to temperature variations and shifting loads. Space applications are also considered.
Hou, Peng-Fei; Chen, Bing-Jie; Zhang, Yang
2017-08-01
As a solid material between the crystal and the amorphous, the study on quasicrystals has become an important branch of condensed matter physics. Due to the special arrangement of atoms, quasicrystals own some desirable properties, such as low friction coefficient, low adhesion, high wear resistance and low porosity. Thus, quasicrystals are expected to be applied to the coating surfaces for engines, solar cells, nuclear fuel containers and heat converters. However, when the quasicrystals are used as coating material, it is very hard to simulate the coupling fields by the finite elements numerical methods because of its thin thickness and extreme stress gradient. This is the main reason why the structure of quasicrystal coating cannot be calculated accurately and stably by various numerical platform. A general solution method which can be used to solve this contact problem for a 1D hexagonal quasicrystal coating perfectly bonded to a transversely isotropic semi-infinite substrate under the point force is presented in this paper. The solutions of the Green's function under the distributed load can be obtained through the superposition principle. The simulation results show that this method is correct and effective, which has high calculation accuracy and fast convergence speed. The phonon-phason coupling field and elastic field in the coating and semi-infinite substrate will be derived based on the axisymmetric general solution, and the complicated coupling field of quasicrystals in coating contact space is explicitly presented in terms of elementary functions. In addition, the relationship between the coating thickness or external force and the stress component is also obtained to solve practical problems in engineering applications. The solutions presented not only bear theoretical merits, but also can serve as benchmarks to clarify various approximate methods.
Near-field imaging of out-of-plane light scattering in photonic crystal slabs
DEFF Research Database (Denmark)
Volkov, Valentyn; Bozhevolnyi, Sergey; Taillaert, Dirk
2003-01-01
A collection scanning near-field optical microscope (SNOM) is used to image the propagating of light at telecommunication wavelengths (1520-1570 nm) along photonic crystal (PC) slabs, which combine slab waveguides with in-plane PCs consisting of one- and two-dimensional gratings. The efficient out......-of-plane light scattering is directly observed for both 1D and 2D gratings (period 590 nm) fabricated on silicon-on-insulator wafers and the corresponding SNOM images are presented. Using the obtained SNOM images, we analyze light intensity distributions along PC gratings measured at different wavelengths and...
Elastic-plastic deformation of fiber composites with a tetragonal structure
Energy Technology Data Exchange (ETDEWEB)
Makarova, E.IU.; Svistkova, L.A. (Permskii Politekhnicheskii Institut, Perm (USSR))
1991-02-01
Results of numerical solutions are presented for elastic-plastic problems concerning arbitrary loading of unidirectional composites in the transverse plane. The nucleation and evolution of microplastic zones in the matrix and the effect of this process on the macroscopic characteristics of the composite are discussed. Attention is also given to the effect of the fiber shape on the elastic-plastic deformation of the matrix and to deformation paths realized in simple microdeformation processes. The discussion is illustrated by results obtained for a composite consisting of a VT1-0 titanium alloy matrix reinforced by Ti-Mo fibers.
Measurements of the elastic electromagnetic form factor ratio {mu}pGEp/GMp via polarization transfer
Energy Technology Data Exchange (ETDEWEB)
Olivier Gayou; Oleksandr Glamazdin; Andrei Afanasev; Arunava Saha; Brendan Fox; Bogdan Wojtsekhowski; C. Chang; Cathleen Jones; Charles Glashausser; Charles Perdrisat; D. Crovelli; Daniel Simon; David Meekins; Demetrius Margaziotis; Dipangkar Dutta; Edgar Kooijman; Elaine Schulte; Edward Brash; Edward Kinney; Eugene Chudakov; Feng Xiong; Franco Garibaldi; Garth Huber; Gerfried Kumbartzki; Guido Urciuoli; Haiyan Gao; Jordan Hovdebo; James Kelly; Javier Gomez; Jens-Ole Hansen; Jian-Ping Chen; John Calarco; John LeRose; Joseph Mitchell; Juncai Gao; Konrad Aniol; Kamal Benslama; Kathy McCormick; Cornelis De Jager; Cornelis de Jager; Kevin Fissum; Krishni Wijesooriya; Louis Bimbot; Ludyvine Morand; Luminita Todor; Moskov Amarian; Marat Rvachev; Mark Jones; Martin Epstein; Meihua Liang; Michael Kuss; Nilanga Liyanage; Adam Sarty; Paul Ulmer; Pete Markowitz; Peter Bosted; R. Holt; Riad Suleiman; Richard Lindgren; Rikki Roche; Robert Michaels; Roman Pomatsalyuk; Ronald Gilman; Ronald Ransome; Stephen Becher; Scott Dumalski; Salvatore Frullani; Seonho Choi; Sergey Malov; Sonja Dieterich; Steffen Strauch; Steve Churchwell; Ting Chang; Viktor Gorbenko; Vina Punjabi; Wang Xu; Xiangdong Ji; Zein-Eddine Meziani; Zhengwei Chai
2001-09-01
We present measurements of the ratio of the proton elastic electromagnetic form factors, {mu}pGEp/GMp. The Jefferson Lab Hall A Focal Plane Polarimeter was used to determine the longitudinal and transverse components of the recoil proton polarization in ep elastic scattering; the ratio of these polarization components is proportional to the ratio of the two form factors. These data reproduce the observation of Jones et al. [Phys. Rev. Lett. 84, 1398 (2000)], that the form factor ratio decreases significantly from unity above Q2 = 1 GeV2.
Elastic-plastic analysis of an infinite sheet having a circular hole under pressure
Hsu, Y. C.; Forman, R. G.
1975-01-01
An exact elastic-plastic solution for the stresses in an infinite sheet having a circular hole subject to pressure is obtained on the basis of J2 deformation theory together with a modified Ramberg-Osgood law. The sheet is orthotropic but isotropic in its plane. The results are assessed on the basis of Budiansky's criterion for the acceptability of J2 deformation theory. By using exact elastic-plastic stresses, the function connecting the pressure at the hole with the radial enlargement is obtained. Upon release of the pressure, residual stresses around the hole are produced.
Numerical prediction of the elastic characteristics of spatially reinforced composite materials
Anoshkin, A. N.; Pisarev, P. V.; Ermakov, D. A.; Maksimova, K. A.
2017-12-01
In this paper, the effective elastic characteristics of spatially reinforced composite materials is calculated. The problem is solved by the finite element method in the Ansys Workbench software using the periodicity cell of the material. When constructing the model, were considered the weaving scheme, the volume fraction of the reinforcing skeleton, and the geometric shape of the reinforcing filaments. The effective elastic modulesare determined by the volume averaging method. To obtain nine independent characteristics of the orthotropic material, six calculation modes were used: tensionalong the axis and ashear in the planes. The stress-strain state of reinforcing filaments is analyzed.
Synthesis and properties of a few 1-D cobaltous fumarates
Energy Technology Data Exchange (ETDEWEB)
Bora, Sanchay J., E-mail: sanchay.bora@gmail.com [Department of Chemistry, Gauhati University, Guwahati 781 014 (India); Das, Birinchi K., E-mail: das_bk@rediffmail.com [Department of Chemistry, Gauhati University, Guwahati 781 014 (India)
2012-08-15
Metal fumarates are often studied in the context of metal organic framework solids. Preparation, structure and properties of three cobalt(II) fumarates, viz. [Co(fum)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O 1, [Co(fum)(py){sub 2}(H{sub 2}O){sub 2}] 2, and [Co(fum)(4-CNpy){sub 2}(H{sub 2}O){sub 2}] 3 (fum=fumarate, py=pyridine, 4-CNpy=4-cyanopyridine) are described. All three are chain polymers involving bridging fumarato ligands between each pair of octahedral Co(II) centres, but while the first one is zigzag in structure, the latter two are linear. Indexed powder X-ray diffraction patterns, solid state electronic spectra and magnetic properties of the species are reported. Thermal decomposition behaviour of the compounds suggests that they may be suitable as precursors to make Co{sub 3}O{sub 4} via pyrolysis below 600 Degree-Sign C. - Graphical abstract: Structure and properties of three chain-polymeric cobalt(II) fumarates are described. Highlights: Black-Right-Pointing-Pointer Three fumarate bridged 1-D coordination polymers of cobalt(II) are reported. Black-Right-Pointing-Pointer While Co(II) fumarate pentahydrate is zigzag, the species having both pyridine and water as co-ligands are linear in structure. Black-Right-Pointing-Pointer Prominent lines in the powder X-ray diffraction patterns have been indexed. Black-Right-Pointing-Pointer Thermal decomposition of the species yields Co{sub 3}O{sub 4} as the final product.
Elastohydrodynamics of elliptical contacts for materials of low elastic modulus
Hamrock, B. J.; Dowson, D.
1983-01-01
The influence of the ellipticity parameter k and the dimensionless speed U, load W, and materials G parameters on minimum film thickness for materials of low elastic modulus was investigated. The ellipticity parameter was varied from 1 (a ball-on-plane configuration) to 12 (a configuration approaching a line contact); U and W were each varied by one order of magnitude. Seventeen cases were used to generate the minimum- and central-film-thickness relations. The influence of lubricant starvation on minimum film thickness in starved elliptical, elastohydrodynamic configurations was also investigated for materials of low elastic modulus. Lubricant starvation was studied simply by moving the inlet boundary closer to the center of the conjunction in the numerical solutions. Contour plots of pressure and film thickness in and around the contact were presented for both fully flooded and starved lubrication conditions. It is evident from these figures that the inlet pressure contours become less circular and closer to the edge of the Hertzian contact zone and that the film thickness decreases substantially as the serverity of starvation increases. The results presented reveal the essential features of both fully flooded and starved, elliptical, elastohydrodynamic conjunctions for materials of low elastic modulus.
Collusion and the elasticity of demand
David Collie
2004-01-01
The analysis of collusion in infinitely repeated Cournot oligopoly games has generally assumed that demand is linear, but this note uses constant-elasticity demand functions to investigate how the elasticity of demand affects the sustainability of collusion.
Dey, Mohar; Bandyopadhyay, Dipankar; Sharma, Ashutosh; Qian, Shizhi; Joo, Sang Woo
2012-10-01
We explore the electric-field-induced interfacial instabilities of a trilayer composed of a thin elastic film confined between two viscous layers. A linear stability analysis (LSA) is performed to uncover the growth rate and length scale of the different unstable modes. Application of a normal external electric field on such a configuration can deform the two coupled elastic-viscous interfaces either by an in-phase bending or an antiphase squeezing mode. The bending mode has a long-wave nature, and is present even at a vanishingly small destabilizing field. In contrast, the squeezing mode has finite wave-number characteristics and originates only beyond a threshold strength of the electric field. This is in contrast to the instabilities of the viscous films with multiple interfaces where both modes are found to possess long-wave characteristics. The elastic film is unstable by bending mode when the stabilizing forces due to the in-plane curvature and the elastic stiffness are strong and the destabilizing electric field is relatively weak. In comparison, as the electric field increases, a subdominant squeezing mode can also appear beyond a threshold destabilizing field. A dominant squeezing mode is observed when the destabilizing field is significantly strong and the elastic films are relatively softer with lower elastic modulus. In the absence of liquid layers, a free elastic film is also found to be unstable by long-wave bending and finite wave-number squeezing modes. The LSA asymptotically recovers the results obtained by the previous formulations where the membrane bending elasticity is approximately incorporated as a correction term in the normal stress boundary condition. Interestingly, the presence of a very weak stabilizing influence due to a smaller interfacial tension at the elastic-viscous interfaces opens up the possibility of fabricating submicron patterns exploiting the instabilities of a trilayer.
Scattering of Airy elastic sheets by a cylindrical cavity in a solid.
Mitri, F G
2017-11-01
The prediction of the elastic scattering by voids (and cracks) in materials is an important process in structural health monitoring, phononic crystals, metamaterials and non-destructive evaluation/imaging to name a few examples. Earlier analytical theories and numerical computations considered the elastic scattering by voids in plane waves of infinite extent. However, current research suggesting the use of (limited-diffracting, accelerating and self-healing) Airy acoustical-sheet beams for non-destructive evaluation or imaging applications in elastic solids requires the development of an improved analytical formalism to predict the scattering efficiency used as a priori information in quantitative material characterization. Based on the definition of the time-averaged scattered power flow density, an analytical expression for the scattering efficiency of a cylindrical empty cavity (i.e., void) encased in an elastic medium is derived for compressional and normally-polarized shear-wave Airy beams. The multipole expansion method using cylindrical wave functions is utilized. Numerical computations for the scattering energy efficiency factors for compressional and shear waves illustrate the analysis with particular emphasis on the Airy beam parameters and the non-dimensional frequency, for various elastic materials surrounding the cavity. The ratio of the compressional to the shear wave speed stimulates the generation of elastic resonances, which are manifested as a series of peaks in the scattering efficiency plots. The present analysis provides an improved method for the computations of the scattering energy efficiency factors using compressional and shear-wave Airy beams in elastic materials as opposed to plane waves of infinite extent. Copyright © 2017 Elsevier B.V. All rights reserved.
Modified elastic tissue-Masson trichrome stain.
Garvey, W
1984-07-01
A combined elastic tissue-Masson technique is presented which stains elastic fibers of all sizes, nuclei and connective tissue. The modified elastic tissue stain consists of hematoxylin, ferric chloride and Verhoeff's iodine; nuclei and elastic fibers are stained blue-black in six minutes without differentiation. By contrast, cytoplasmic elements are stained red, (Biebrich scarlet-acid fuchsin) and collagen is stained green (light green) or blue (aniline blue). The entire staining procedure takes approximately one hour.
Elastic least-squares reverse time migration
Feng, Zongcai
2016-09-06
Elastic least-squares reverse time migration (LSRTM) is used to invert synthetic particle-velocity data and crosswell pressure field data. The migration images consist of both the P- and Svelocity perturbation images. Numerical tests on synthetic and field data illustrate the advantages of elastic LSRTM over elastic reverse time migration (RTM). In addition, elastic LSRTM images are better focused and have better reflector continuity than do the acoustic LSRTM images.
Effects of texture on shear band formation in plane strain tension/compression and bending
DEFF Research Database (Denmark)
Kuroda, M.; Tvergaard, Viggo
2007-01-01
model analysis. Third, shear band developments in plane strain pure bending of a sheet specimen with the typical textures are studied. Regions near the surfaces in a bent sheet specimen are approximately subjected to plane strain tension or compression. From this viewpoint, the bendability of a sheet......In this study, effects of typical texture components observed in rolled aluminum alloy sheets on shear band formation in plane strain tension/compression and bending are systematically studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain...... is characterized in terms of an elastic-viscoplastic continuum slip constitutive relation. First, a simple model analysis in which the shear band is assumed to occur in a weaker thin slice of material is performed. From this simple model analysis, two important quantities regarding shear band formation...
Numerical analysis of dynamic out-of-plane loading of nonwovens
Demirci, E.; Farukh, F.; Acar, M.; Pourdeyhimi, B.; Silberschmidt, V. V.
2013-07-01
This paper presents finite element (FE) modelling of deformation behaviour of thermally bonded bicomponent fibre nonwovens under out-of-plane dynamic loading. Nonwoven fabric was treated as an assembly of two regions with distinct mechanical properties. Bond points were treated as composite material having a matrix of the sheath material reinforced with fibres of the core material. Elastic-plastic and viscous properties of the constituent fibres, obtained with tensile and relaxation tests were implemented into the FE model. The mechanical behaviour of the material under out-of-plane dynamic loading was observed with visual techniques. The deformation behaviour of nonwoven under out-of-plane dynamic loading computed with the numerical model was compared with that observed in the tests.
D'Avila, Maria Paola Santisi; Semblat, Jean-François
2014-01-01
We propose a one-directional three-component (1D-3C) approach to model the unidirectional (1D) propagation of a three component (3C) earthquake for seismic response analyses of horizontal multilayer soils, considering a 3D nonlinear constitutive behaviour for soils. An elasto-plastic cyclic constitutive behaviour of the Masing-Prandtl-Iwan type, using just the shear modulus decay curve for soil characterization, is implemented in a finite element scheme. Seismic response of soil profiles appears dependent on incident wave polarization, elastic and dynamic properties of medium and seismic impedance contrast between soil layers. Propagating a 3C signal induces a multiaxial stress interaction decreasing soil strength and increasing nonlinear effects. Soil profiles in the Tohoku area (Japan) are loaded by seismic signals recorded at outcrops or downhole, during the 2011 Tohoku earthquake. The nonlinear seismic response of each soil profile, represented in terms of acceleration, hysteresis loops and stress and str...
How can cells sense the elasticity of a substrate? An analysis using a cell tensegrity model.
De Santis, G; Lennon, A B; Boschetti, F; Verhegghe, B; Verdonck, P; Prendergast, P J
2011-10-11
A eukaryotic cell attaches and spreads on substrates, whether it is the extracellular matrix naturally produced by the cell itself, or artificial materials, such as tissue-engineered scaffolds. Attachment and spreading require the cell to apply forces in the nN range to the substrate via adhesion sites, and these forces are balanced by the elastic response of the substrate. This mechanical interaction is one determinant of cell morphology and, ultimately, cell phenotype. In this paper we use a finite element model of a cell, with a tensegrity structure to model the cytoskeleton of actin filaments and microtubules, to explore the way cells sense the stiffness of the substrate and thereby adapt to it. To support the computational results, an analytical 1D model is developed for comparison. We find that (i) the tensegrity hypothesis of the cytoskeleton is sufficient to explain the matrix-elasticity sensing, (ii) cell sensitivity is not constant but has a bell-shaped distribution over the physiological matrix-elasticity range, and (iii) the position of the sensitivity peak over the matrix-elasticity range depends on the cytoskeletal structure and in particular on the F-actin organisation. Our model suggests that F-actin reorganisation observed in mesenchymal stem cells (MSCs) in response to change of matrix elasticity is a structural-remodelling process that shifts the sensitivity peak towards the new value of matrix elasticity. This finding discloses a potential regulatory role of scaffold stiffness for cell differentiation.
Thermodynamic parameters of elasticity and electrical conductivity ...
African Journals Online (AJOL)
The thermodynamic parameters (change in free energy of elasticity, DGe; change in enthalpy of elasticity, DHe; and change in entropy of elasticity, DSe) and the electrical conductivity of natural rubber composites reinforced separately with some agricultural wastes have been determined. Results show that the reinforced ...
Some Measurements of Elasticities of Substitution
J. Tinbergen (Jan)
1946-01-01
textabstractSo far, when measuring elasticities of demand, most econometricians have concentrated upon the plain elasticity of total demand for a given commodity. For many important problems we should, in addition, like to know something of "partial elasticities," as I might provisionally call them.
Data of evolutionary structure change: 1D3AB-1SMKC [Confc[Archive
Lifescience Database Archive (English)
Full Text Available 1D3AB-1SMKC 1D3A 1SMK B C -TKVSVVGAAGTVGAAAGYNIALRDIADEVVFVDIPDKEDDTVGQAADTNHGIAYD...KLSDQYDKIS----- GFKVAILGAAGGIGQPLAMLMKMNPLVSVLHLYDV----VNAPGVTADISHMD---TGAVVRGFLGQQQLE... 1SMK C 1SMKC 1SMK C 1SMKC 1SMK C 1SMKC
Data of evolutionary structure change: 1D3AA-1SMKD [Confc[Archive
Lifescience Database Archive (English)
Full Text Available 1D3AA-1SMKD 1D3A 1SMK A D -TKVSVVGAAGTVGAAAGYNIALRDIADEVVFVDIPDKEDDTVGQAADTNHGIAYD...KLSDQYDKIS----- GFKVAILGAAGGIGQPLAMLMKMNPLVSVLHLYDV----VNAPGVTADISHMD---TGAVVRGFLGQQQLE... 1SMK D 1SMKD 1SMK D 1SMKD 1SMK D 1SMKD
Data of evolutionary structure change: 1D3AB-1SMKG [Confc[Archive
Lifescience Database Archive (English)
Full Text Available 1D3AB-1SMKG 1D3A 1SMK B G -TKVSVVGAAGTVGAAAGYNIALRDIADEVVFVDIPDKEDDTVGQAADTNHGIAYD...--AEKLSDQYDKIS- GFKVAILGAAGGIGQPLAMLMKMNPLVSVLHLYDV----VNAPGVTADISHMD---TGAVVRGFLGQQQLE... 1SMK G 1SMKG 1SMK G 1SMKG 1SMK G 1SMKG
DEFF Research Database (Denmark)
Jacque, C M; Baumann, N A; Bock, E
1976-01-01
Seven antigens specific to the nervous tissue were measured in both Jimpy and control mice. The D5 and the GFA protein, both components of the glia, are strongly increased in the mutant while the neuronal components 14-3-2, synaptin C1, D1, D2 and D3 are unchanged....
Engineering 1D Quantum Stripes from Superlattices of 2D Layered Materials
Energy Technology Data Exchange (ETDEWEB)
Gruenewald, John H.; Kim, Jungho; Kim, Heung Sik; Johnson, Jared M.; Hwang, Jinwoo; Souri, Maryam; Terzic, Jasminka; Chang, Seo Hyoung; Said, Ayman; Brill, Joseph W.; Cao, Gang; Kee, Hae-young; Seo, Sung S. Ambrose
2017-01-04
Dimensional tunability from two dimensions to one dimension is demonstrated for the first time using an artificial superlattice method in synthesizing 1D stripes from 2D layered materials. The 1D confinement of layered Sr2IrO4 induces distinct 1D quantum-confined electronic states, as observed from optical spectroscopy and resonant inelastic X-ray scattering. This 1D superlattice approach is generalizable to a wide range of layered materials.
Elasticity of Long Distance Travelling
DEFF Research Database (Denmark)
Knudsen, Mette Aagaard
2011-01-01
a household. Due to a high share of corner solutions among the expenditures on plane tickets and package travelling, the expenditures on these specific commodities are examined with a Tobit approach. The model results find both plane tickets and travel packages to be luxury goods. It also states that travel......With data from the Danish expenditure survey for 12 years 1996 through 2007, this study analyses household expenditures for long distance travelling. Household expenditures are examined at two levels of aggregation having the general expenditures on transportation and leisure relative to five other...
The Rab-GTPase-activating protein TBC1D1 regulates skeletal muscle glucose metabolism
DEFF Research Database (Denmark)
Szekeres, Ferenc; Chadt, Alexandra; Tom, Robby Z
2012-01-01
The Rab-GTPase-activating protein TBC1D1 has emerged as a novel candidate involved in metabolic regulation. Our aim was to determine whether TBC1D1 is involved in insulin as well as energy-sensing signals controlling skeletal muscle metabolism. TBC1D1-deficient congenic B6.SJL-Nob1.10 (Nob1.10(SJ...
A Collaborative Knowledge Plane for Autonomic Networks
Mbaye, Maïssa; Krief, Francine
Autonomic networking aims to give network components self-managing capabilities. Several autonomic architectures have been proposed. Each of these architectures includes sort of a knowledge plane which is very important to mimic an autonomic behavior. Knowledge plane has a central role for self-functions by providing suitable knowledge to equipment and needs to learn new strategies for more accuracy.However, defining knowledge plane's architecture is still a challenge for researchers. Specially, defining the way cognitive supports interact each other in knowledge plane and implementing them. Decision making process depends on these interactions between reasoning and learning parts of knowledge plane. In this paper we propose a knowledge plane's architecture based on machine learning (inductive logic programming) paradigm and situated view to deal with distributed environment. This architecture is focused on two self-functions that include all other self-functions: self-adaptation and self-organization. Study cases are given and implemented.
Tavakoli, J; Costi, J J
2017-12-19
The relationship between elastic fibre disorders and disc degeneration, aging and progression of spine deformity have been discussed in a small number of studies. However, the clinical relevance of elastic fibres in the annulus fibrosus (AF) of the disc is poorly understood. Ultrastructural visualization of elastic fibres is an important step towards understanding their structure-function relationship. In our previous studies, a novel technique for visualization of elastic fibres across the AF was presented and their ultrastructural organization in intra- and inter-lamellar regions was compared. Using the same novel technique in the present study, the ultrastructural organization of elastic fibres in the partition boundaries (PBs), which are located between adjacent collagen bundles, is presented for the first time. Visualization of elastic fibres in the PBs in control and partially digested (digested) samples was compared, and their orientation in two different cutting planes (transverse and oblique) were discussed. The ultrastructural analysis revealed that elastic fibres in PBs were a well-organized dense and complex network having different size and shape. Adjacent collagen bundles in a cross section (CS) lamella appear to be connected to each other, where elastic fibres in the PBs were merged in parallel or penetrated into the collagen bundles. There was no significant difference in directional coherency coefficient of elastic fibres between the two different cutting planes (p = .35). The present study revealed that a continuous network of elastic fibres may provide disc integrity by connecting adjacent bundles of CS lamellae together. Compared to our previous studies, the density of the elastic fibre network in PBs was lower, and fibre orientation was similar to the intra-lamellar space and inter-lamellar matrix. A detailed ultrastructural study in the partition boundaries of the annulus fibrosus within the disc revealed a well-organized elastic fibre
Radioactivity in the galactic plane
Walraven, G. D.; Haymes, R. C.
1976-01-01
The paper reports the detection of a large concentration of interstellar radioactivity during balloon-altitude measurements of gamma-ray energy spectra in the band between 0.02 and 12.27 MeV from galactic and extragalactic sources. Enhanced counting rates were observed in three directions towards the plane of the Galaxy; a power-law energy spectrum is computed for one of these directions (designated B 10). A large statistical deviation from the power law in a 1.0-FWHM interval centered near 1.16 MeV is discussed, and the existence of a nuclear gamma-ray line at 1.15 MeV in B 10 is postulated. It is suggested that Ca-44, which emits gamma radiation at 1.156 MeV following the decay of radioactive Sc-44, is a likely candidate for this line, noting that Sc-44 arises from Ti-44 according to explosive models of supernova nucleosynthesis. The 1.16-MeV line flux inferred from the present data is shown to equal the predicted flux for a supernova at a distance of approximately 3 kpc and an age not exceeding about 100 years.
Luminosity calibration from elastic scattering
Stenzel, H
2006-01-01
The absolute luminosity of the LHC at the ATLAS interaction point will be calibrated by the measurement of the t-distribution of elastic pp-scattering in the Coulomb-Nuclear interference region. The ALFA detector housed in Roman Pots located 240m away from IP1 is designed to approach the beam at mm distance and to measure elastic pp-scattering at micro-radian scattering angles. This measurement will be performed with dedicated runs using a special beam optics with high beta* and parallel-to-point focusing in order to access the Coulomb regime. In this note the expected performance of this method, evaluated with a simulation of the experimental set-up, is presented.
Elastic sealants for surgical applications.
Annabi, Nasim; Yue, Kan; Tamayol, Ali; Khademhosseini, Ali
2015-09-01
Sealants have emerged as promising candidates for replacing sutures and staples to prevent air and liquid leakages during and after the surgeries. Their physical properties and adhesion strength to seal the wound area without limiting the tissue movement and function are key factors in their successful implementation in clinical practice. In this contribution, the advances in the development of elastic sealants formed from synthetic and natural materials are critically reviewed and their shortcomings are pointed out. In addition, we highlight the applications in which elasticity of the sealant is critical and outline the limitations of the currently available sealants. This review will provide insights for the development of novel bioadhesives with advanced functionality for surgical applications. Copyright © 2015 Elsevier B.V. All rights reserved.
Elasticity of Crosslinked Biopolymer Networks
Lubensky, Tom
2007-03-01
Crosslinked networks of biopolymers exhibit an enormous variety of nonlinear elastic behaviors depending on the rigidity of constituent polymers and the geometry and topology of the network. This talk will present a brief review of the general theory of nonlinear elasticity. It will then discuss the phenomenon of strain stiffening in networks of semiflexible polymers and present a theory [1] of this phenomena based on the nonlinear force-extension curve of these polymers and the simplifying assumption of affine response. The nonlinear stress-strain curves predicted by this theory agree remarkably well with experiments on a number of different polymer networks. Limitations and extensions of the simple theory including extensions to nonaffine behavior will also be discussed. [1] Storm, Cornelis, Jennifer J. Pastore, Jennifer J., Fred C. MacKintosh, Fred C., T.C. Lubensky, T.C., and Paul A. Janmey, Paul A., Nature 435, 191-194 (2005).
Elasticity of Relativistic Rigid Bodies?
Smarandache, Florentin
2013-10-01
In the classical Twin Paradox, according to the Special Theory of Relativity, when the traveling twin blasts off from the Earth to a relative velocity v =√{/3 } 2 c with respect to the Earth, his measuring stick and other physical objects in the direction of relative motion shrink to half their lengths. How is that possible in the real physical world to have let's say a rigid rocket shrinking to half and then later elongated back to normal as an elastic material when it stops? What is the explanation for the traveler's measuring stick and other physical objects, in effect, return to the same length to their original length in the Stay-At-Home, but there is no record of their having shrunk? If it's a rigid (not elastic) object, how can it shrink and then elongate back to normal? It might get broken in such situation.
In vivo measurements of human neck skin elasticity using MRI and finite element modeling.
An, Yunqiang; Ji, Changjin; Li, Yong; Wang, Jianxia; Zhang, Xinyue; Huang, Yaqi
2017-04-01
The assessment of mechanical properties of the human skin is very important in investigating the mechanism of obstructive sleep apnea, a common disorder characterized by repetitive collapse and obstruction of the upper airway during sleep. In this study, a unique method, combining magnetic resonance imaging (MRI) and finite element modeling (FEM), was developed to obtain the value of the in vivo elastic modulus of the neck skin. A total of 22 subjects, 16 males and six females, were recruited to participate in the MRI studies. The changes in the airway and the neck size resulting from fluid shift from the lower body to the neck were measured based on the MR images. A two-dimensional plane strain FE model was built to simulate such changes in the neck cross-section for each subject. Solving an inverse problem using FEM by matching the measured data, we obtained the in vivo elastic modulus of the neck skin to be 1.78 ± 1.73 MPa. Results showed that the elastic modulus tended to increase with age and body mass index for these subjects. A sensitivity analysis of the muscle and fat mechanical parameters was also performed to test their effects on the predicted skin elasticity. The unique method developed in this study for measuring the in vivo elastic modulus of the neck skin is quite effective, and the skin elasticity value obtained using this method is credible. © 2017 American Association of Physicists in Medicine.
RF/Optical Demonstration: Focal Plane Assembly
Hoppe, D. J.; Chung, S.; Kovalik, J.; Gama, E.; Fernandez, M. M.
2016-11-01
In this article, we describe the second-generation focal plane optical assembly employed in the RF/optical demonstration at DSS-13. This assembly receives reflected light from the two mirror segments mounted on the RF primary. The focal plane assembly contains a fast steering mirror (FSM) to stabilize the focal plane spot, a pupil camera to aid in aligning the two segments, and several additional cameras for receiving the optical signal prior to as well as after the FSM loop.
Elastic sealants for surgical applications
Annabi, Nasim; Yue, Kan; Tamayol, Ali; Khademhosseini, Ali
2015-01-01
Sealants have emerged as promising candidates for replacing sutures and staples to prevent air and liquid leakages during and after the surgeries. Their physical properties and adhesion strength to seal the wound area without limiting the tissue movement and function are key factors in their successful implementation in clinical practice. In this contribution, the advances in the development of elastic sealants formed from synthetic and natural materials are critically reviewed and their shor...
Transient waves in visco-elastic media
Ricker, Norman
1977-01-01
Developments in Solid Earth Geophysics 10: Transient Waves in Visco-Elastic Media deals with the propagation of transient elastic disturbances in visco-elastic media. More specifically, it explores the visco-elastic behavior of a medium, whether gaseous, liquid, or solid, for very-small-amplitude disturbances. This volume provides a historical overview of the theory of the propagation of elastic waves in solid bodies, along with seismic prospecting and the nature of seismograms. It also discusses the seismic experiments, the behavior of waves propagated in accordance with the Stokes wave
Large Format Uncooled Focal Plane Array Project
National Aeronautics and Space Administration — Black Forest Engineering has identified innovative modifications in uncooled focal plane array (UFPA) architecture and processing that allows development of large...
Energy Technology Data Exchange (ETDEWEB)
Taylor, DeCarlos E., E-mail: decarlos.e.taylor.civ@mail.mil [U.S. Army Research Laboratory, Aberdeen Proving Ground, Maryland 21005 (United States)
2014-08-07
The elastic constants of the α and γ polymorphs of cyclotrimethylene trinitramine (RDX) have been computed using dispersion corrected density functional theory (DFT). The DFT results validate the values obtained in several experiments using ultrasonic and impulsive stimulated thermal scattering techniques and disagree with those obtained using Brillouin scattering which, in general, exceed the other experimental and theoretical results. Compressibility diagrams at zero pressure are presented for the ab, ac, and bc crystallographic planes, and the anisotropic linear compressibility within the ac plane of α-RDX at 0 GPa, observed using ultrasonic and impulsive stimulated thermal scattering measurements, is verified using DFT. The pressure dependence of the elastic constants of α-RDX (0–4 GPa) and γ-RDX (4–8 GPa) is also presented.
Zero-frequency and slow elastic modes in phononic monolayer granular membranes.
Zheng, Li-Yang; Pichard, Hélène; Tournat, Vincent; Theocharis, Georgios; Gusev, Vitalyi
2016-07-01
We theoretically study the dispersion properties of elastic waves in hexagonal and honeycomb monolayer granular membranes with either out-of-plane or in-plane particle motion. The particles interact predominantly via normal and transverse contact rigidities. When rotational degrees of freedom are taken into account, the bending and torsional rigidities of the intergrain contacts can control some of the phononic modes. The existence of zero-frequency modes, zero-group-velocity modes and their transformation into slow propagating phononic modes due to weak bending and torsional intergrain interactions are investigated. We also study the formation and manipulation of Dirac cones and multiple degenerated modes. This could motivate variety of potential applications in elastic waves control by manipulating the contact rigidities in granular phononic crystals. Copyright © 2015 Elsevier B.V. All rights reserved.
In-situ neutron diffraction of LaCoO3 perovskite under uniaxial compression. II. Elastic properties
Lugovy, Mykola; Aman, Amjad; Chen, Yan; Orlovskaya, Nina; Kuebler, Jakob; Graule, Thomas; Reece, Michael J.; Ma, Dong; Stoica, Alexandru D.; An, Ke
2014-07-01
Calculations of elastic constants and development of elastic anisotropy under uniaxial compression in originally isotropic polycrystalline LaCoO3 perovskite are reported. The lattice strains in individual (hkl) planes as well as average lattice strain were determined both for planes oriented perpendicular and parallel to the loading direction using in-situ neutron diffraction. Utilizing average lattice strains as well as lattice strains along the a and c crystallographic directions, an attempt was made to determine Poisson's ratio of LaCoO3, which was then compared with that measured using an impulse excitation technique. The elastic constants were calculated and Young's moduli of LaCoO3 single crystal in different crystallographic directions were estimated.
Energy Technology Data Exchange (ETDEWEB)
Lugovy, Mykola [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Institute for Problems of Materials Science, Kiev 03142 (Ukraine); Aman, Amjad; Orlovskaya, Nina, E-mail: Nina.Orlovskaya@ucf.edu [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Chen, Yan [Department of Mechanical and Aerospace Engineering, University of Central Florida, Orlando, Florida 32816 (United States); Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Kuebler, Jakob; Graule, Thomas [Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for High Performance Ceramics, Ueberlandstrasse 129, 8600 Duebendorf (Switzerland); Reece, Michael J. [The School of Engineering and Materials Science, Queen Mary, University of London, London E1 4NS (United Kingdom); Ma, Dong; Stoica, Alexandru D.; An, Ke [Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
2014-07-07
Calculations of elastic constants and development of elastic anisotropy under uniaxial compression in originally isotropic polycrystalline LaCoO{sub 3} perovskite are reported. The lattice strains in individual (hkl) planes as well as average lattice strain were determined both for planes oriented perpendicular and parallel to the loading direction using in-situ neutron diffraction. Utilizing average lattice strains as well as lattice strains along the a and c crystallographic directions, an attempt was made to determine Poisson's ratio of LaCoO{sub 3}, which was then compared with that measured using an impulse excitation technique. The elastic constants were calculated and Young's moduli of LaCoO{sub 3} single crystal in different crystallographic directions were estimated.
Modelling the elastic properties of cellulose nanopaper
DEFF Research Database (Denmark)
Mao, Rui; Goutianos, Stergios; Tu, Wei
2017-01-01
The elastic modulus of cellulose nanopaper was predicted using a two-dimensional (2D) micromechanical fibrous network model. The elastic modulus predicted by the network model was 12 GPa, which is well within the range of experimental data for cellulose nanopapers. The stress state in the network...... revealed both tensile and compressive stresses during elastic deformation of the model. The length, diameter, waviness and elastic modulus of the cellulose nanofibres were varied in the model and their effect on the elastic modulus of fibrous networks was studied. It was found that high values of elastic...... moduli of cellulose networks could be obtained for long, thin and straight nanofibres of high stiffness. The effect of inter-fibre bonding and network density was also investigated. Increasing fibre-fibre interactions facilitated stress transfer in cellulose networks and led to a higher elastic modulus...
One-Dimensional Mass-Spring Chains Supporting Elastic Waves with Non-Conventional Topology
Directory of Open Access Journals (Sweden)
2016-04-01
Full Text Available There are two classes of phononic structures that can support elastic waves with non-conventional topology, namely intrinsic and extrinsic systems. The non-conventional topology of elastic wave results from breaking time reversal symmetry (T-symmetry of wave propagation. In extrinsic systems, energy is injected into the phononic structure to break T-symmetry. In intrinsic systems symmetry is broken through the medium microstructure that may lead to internal resonances. Mass-spring composite structures are introduced as metaphors for more complex phononic crystals with non-conventional topology. The elastic wave equation of motion of an intrinsic phononic structure composed of two coupled one-dimensional (1D harmonic chains can be factored into a Dirac-like equation, leading to antisymmetric modes that have spinor character and therefore non-conventional topology in wave number space. The topology of the elastic waves can be further modified by subjecting phononic structures to externally-induced spatio-temporal modulation of their elastic properties. Such modulations can be actuated through photo-elastic effects, magneto-elastic effects, piezo-electric effects or external mechanical effects. We also uncover an analogy between a combined intrinsic-extrinsic systems composed of a simple one-dimensional harmonic chain coupled to a rigid substrate subjected to a spatio-temporal modulation of the side spring stiffness and the Dirac equation in the presence of an electromagnetic field. The modulation is shown to be able to tune the spinor part of the elastic wave function and therefore its topology. This analogy between classical mechanics and quantum phenomena offers new modalities for developing more complex functions of phononic crystals and acoustic metamaterials.
Motivation and compliance with intraoral elastics.
Veeroo, Helen J; Cunningham, Susan J; Newton, Jonathon Timothy; Travess, Helen C
2014-07-01
Intraoral elastics are commonly used in orthodontics and require regular changing to be effective. Unfortunately, poor compliance with elastics is often encountered, especially in adolescents. Intention for an action and its implementation can be improved using "if-then" plans that spell out when, where, and how a set goal, such as elastic wear, can be put into action. Our aim was to determine the effect of if-then plans on compliance with elastics. To identify common barriers to compliance with recommendations concerning elastic wear, semistructured interviews were carried out with 14 adolescent orthodontic patients wearing intraoral elastics full time. Emerging themes were used to develop if-then plans to improve compliance with elastic wear. A prospective pilot study assessed the effectiveness of if-then planning aimed at overcoming the identified barriers on compliance with elastic wear. Twelve participants were randomized equally into study and control groups; the study group received information about if-then planning. The participants were asked to collect used elastics, and counts of these were used to assess compliance. A wide range of motivational and volitional factors were described by the interviewed participants, including the perceived benefits of elastics, cues to remember, pain, eating, social situations, sports, loss of elastics, and breakages. Compliance with elastic wear was highly variable among patients. The study group returned more used elastics, suggesting increased compliance, but the difference was not significant. The use of if-then plans might improve compliance with elastic wear when compared with routine clinical instructions. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.
A Sibelobe Suppressing Beamformer for Coherent Plane Wave Compounding
Directory of Open Access Journals (Sweden)
Wei Guo
2016-11-01
Full Text Available Contrast degradation is a critical problem in ultrasound plane wave imaging (PWI resulting from signals leakage from the sidelobes. An ideal sidelobe reduction method may enhance the contrast without remarkably increasing computational load. To this end, we introduce a new singular value decomposition (SVD sidelobe reduction beamformer for coherent plane wave compounding (CPWC based on a previous work. The SVD takes advantage of the benefits of the different features of the mainlobe and sibelobe in terms of spatio-angular coherence and removes the sidelobes before the final coherent summation. This SVD-based method provides a three-dimensional approach (2D in the space and 1D in the angle while the computation load is kept satisfactory by a dimension-reduced operation before the SVD. To directly observe the sidelobe level, we demonstrate the performance of our SVD method with a point spread function (PSF simulation. Compared to CPWC, our method shows a 6.2 dB reduction in the peak sidelobe level (PSL. We also applied our method to the anechoic cyst inside the speckle for the imaging contrast. Both in the simulation and phantom studies, our method enhances the contrast-to-noise ratio (CNR by more than 10%. Therefore, this new beamformer can be an efficient way to suppress sidelobes in PWI.
Static response of elastic inflated wrinkled membranes
Barsotti, Riccardo; Ligarò, Salvatore S.
2014-05-01
In this paper we present an effective numerical algorithm for determining the equilibrium shapes of inflated elastic membranes susceptible to wrinkling. The use of a two-state constitutive law and the introduction of a suitable criterion allow for accounting for wrinkling of the membrane, although in an approximated way. In the active state, the material is able to transmit only tensile stresses; vice versa, in the passive state it is stress-free and can contract freely. Equilibrium of the membrane in the current inflated configuration is enforced by recourse to the minimum total potential energy principle, whereas the Lagrange multipliers method is used to solve the minimum problem by accounting for the aforesaid nonlinear constitutive law. We use an expressly developed iterative-incremental numerical algorithm, consistent with the established governing set of equations, for accurately monitoring the evolution of the stress field in the membrane during the inflation process. Specifically, we suppose that the membrane reaches its final shape at the end of a four-stage loading process corresponding to the temporary enforcement and the subsequent removal of a fictitious antagonist plane traction acting uniformly along its entire boundary. By this way it is possible to solve with great accuracy the set of governing equilibrium equations by means of a numerical procedure in which the membrane's tangent stiffness is always kept different from zero. The soundness of the proposed algorithm is verified by comparing the results with well-known solutions available in the literature. In particular, for each specific value of pressure, the current configuration of the inflated membrane found by assuming that compressions are allowed is compared in details to the corresponding pseudo-deformed surface, obtained by assuming a tension-only response.
Energy Technology Data Exchange (ETDEWEB)
Nihei, K.T.; Nakagawa, S.; Reverdy, F.; Meyer, L.R.; Duranti, L.; Ball, G.
2010-12-15
Sediments undergoing compaction typically exhibit transversely isotropic (TI) elastic properties. We present a new experimental apparatus, the phased array compaction cell, for measuring the TI elastic properties of clay-rich sediments during compaction. This apparatus uses matched sets of P- and S-wave ultrasonic transducers located along the sides of the sample and an ultrasonic P-wave phased array source, together with a miniature P-wave receiver on the top and bottom ends of the sample. The phased array measurements are used to form plane P-waves that provide estimates of the phase velocities over a range of angles. From these measurements, the five TI elastic constants can be recovered as the sediment is compacted, without the need for sample unloading, recoring, or reorienting. This paper provides descriptions of the apparatus, the data processing, and an application demonstrating recovery of the evolving TI properties of a compacting marine sediment sample.
Modeling and analysis of waves in a heat conducting thermo-elastic plate of elliptical shape
Directory of Open Access Journals (Sweden)
R. Selvamani
Full Text Available Wave propagation in heat conducting thermo elastic plate of elliptical cross-section is studied using the Fourier expansion collocation method based on Suhubi's generalized theory. The equations of motion based on two-dimensional theory of elasticity is applied under the plane strain assumption of generalized thermo elastic plate of elliptical cross-sections composed of homogeneous isotropic material. The frequency equations are obtained by using the boundary conditions along outer and inner surface of elliptical cross-sectional plate using Fourier expansion collocation method. The computed non-dimensional frequency, velocity and quality factor are plotted in dispersion curves for longitudinal and flexural (symmetric and antisymmetric modes of vibrations.
Fatima, Bushra; Acharya, Nikita; Sanyal, Sankar P.
2016-05-01
The structural stability, electronic structure, elastic and mechanical properties of TiZn and ZrZn intermetallics have been studied using ab-initio full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation for exchange and correlation potentials. The various structural parameters, such as lattice constant (a0), bulk modulus (B), and its pressure derivative (B') are analysed and compared. The investigation of elastic constants affirm that both TiZn and ZrZn are elastically stable in CsCl (B2 phase) structure. The electronic structures have been analysed quantitatively from the band structure which reveals the metallic nature of these compounds. To better illustrate the nature of bonding and charge transfer, we have also studied the Fermi surfaces. The three well known criterion of ductility namely Pugh's rule, Cauchy's pressure and Frantsevich rule elucidate the ductile nature of these compounds.
Energy Technology Data Exchange (ETDEWEB)
Fatima, Bushra, E-mail: bushrafatima25@gmail.com; Acharya, Nikita; Sanyal, Sankar P. [Department of Physics, Barkatullah University, Bhopal, 462026 (India)
2016-05-06
The structural stability, electronic structure, elastic and mechanical properties of TiZn and ZrZn intermetallics have been studied using ab-initio full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation for exchange and correlation potentials. The various structural parameters, such as lattice constant (a{sub 0}), bulk modulus (B), and its pressure derivative (B’) are analysed and compared. The investigation of elastic constants affirm that both TiZn and ZrZn are elastically stable in CsCl (B{sub 2} phase) structure. The electronic structures have been analysed quantitatively from the band structure which reveals the metallic nature of these compounds. To better illustrate the nature of bonding and charge transfer, we have also studied the Fermi surfaces. The three well known criterion of ductility namely Pugh’s rule, Cauchy’s pressure and Frantsevich rule elucidate the ductile nature of these compounds.
Steady-state, elastic-plastic growth of slanted cracks in symmetrically loaded plates
DEFF Research Database (Denmark)
Nielsen, Kim Lau; Hutchinson, J. W.
2017-01-01
Elastic and elastic-plastic results are obtained for a semi-infinite slanted through-crack propagating in a symmetrically loaded plate strip with the aim of providing theoretical background to commonly observed plate tearing behavior. Were it is not for the slant of the crack through the thickness...... of the plate, the problem would be mode I, but due to the slant the local conditions along the crack front are a combination of mode I and mode III. A three-dimensional formulation for steady-state crack propagation is employed to generate distributions of effective stress, stress triaxiality and Lode...... parameter through the plate in the plastic zone at the crack tip. The distribution of the mode I and mode III stress intensity factors along the crack front are obtained for the elastic problem. The out-of-plane bending constraint imposed on the plate significantly influences the mixed mode behavior along...
Focal-plane sensor-processor chips
Zarándy, Ákos
2011-01-01
Focal-Plane Sensor-Processor Chips explores both the implementation and application of state-of-the-art vision chips. Presenting an overview of focal plane chip technology, the text discusses smart imagers and cellular wave computers, along with numerous examples of current vision chips.
The variability plane of accreting compact objects
Körding, E.G.; Migliari, S.; Fender, R.; Belloni, T.; Knigge, C.; McHardy, I.
2007-01-01
Recently, it has been shown that soft-state black hole X-ray binaries and active galactic nuclei populate a plane in the space defined by the black hole mass, accretion rate and characteristic frequency. We show that this plane can be extended to hard-state objects if one allows a constant offset
Andrews, D.J.
1985-01-01
A numerical boundary integral method, relating slip and traction on a plane in an elastic medium by convolution with a discretized Green function, can be linked to a slip-dependent friction law on the fault plane. Such a method is developed here in two-dimensional plane-strain geometry. Spontaneous plane-strain shear ruptures can make a transition from sub-Rayleigh to near-P propagation velocity. Results from the boundary integral method agree with earlier results from a finite difference method on the location of this transition in parameter space. The methods differ in their prediction of rupture velocity following the transition. The trailing edge of the cohesive zone propagates at the P-wave velocity after the transition in the boundary integral calculations. Refs.
The transverse shear deformation behaviour of magneto-electro-elastic shell
Energy Technology Data Exchange (ETDEWEB)
Albarody, Thar M. Badri; Al-Kayiem, Hussain H. [UniversitiTeknologi PETRONAS, Perak (Malaysia); Faris, Waleed [International Islamic University Malaysia, Perak (Malaysia)
2016-01-15
Compared to the large number of possible magneto-electro-elastic shell theories, very few exact solutions determining the in-plane stresses, electric displacements and magnetic inductions are possible. While, solving the magneto-electro-elastic shell equations in terms of thermo-magneto-electro-elastic generalized field functions on arbitrary domains and for general conditions exactly are not always possible. In the present work, a linear version of magneto-electro-elastic shell with simply supported boundary conditions, solved exactly, provided that the lamination scheme is cross-ply or anti-symmetric angle-ply laminates. The exact solution that introduced herein can measure the in-plane stresses, electric displacements and magnetic inductions. It also allow for an accurate and usually elegant and conclusive investigation of the various sensations in a shell structure. However, it is important for micro-electro-mechanical shell applications to have an approach available that gives the transverse shear deformation Behaviour for cases that cannot examine experimentally. An investigated examples were accompanied and noteworthy conclusions were drawn which highlight the issues of the implementation of the exact solution, implication of the effects of the material properties, lay-ups of the constituent layers, and shell parameters on the static Behaviour.
Slipping and rolling on an inclined plane
Energy Technology Data Exchange (ETDEWEB)
Aghamohammadi, Cina [Department of Electrical Engineering, Sharif University of Technology, PO Box 11365-11155, Tehran (Iran, Islamic Republic of); Aghamohammadi, Amir, E-mail: mohamadi@alzahra.ac.ir [Department of Physics, Alzahra University, Tehran 19938-91176 (Iran, Islamic Republic of)
2011-07-15
In the first part of the paper, using a direct calculation two-dimensional motion of a particle sliding on an inclined plane is investigated for general values of friction coefficient ({mu}). A parametric equation for the trajectory of the particle is also obtained. In the second part of the paper, the motion of a sphere on the inclined plane is studied. It is shown that the evolution equation for the contact point of a sliding sphere is similar to that of a point particle sliding on an inclined plane whose friction coefficient is 7/2 {mu}. If {mu} > 2/7 tan {theta}, for any arbitrary initial velocity and angular velocity, the sphere will roll on the inclined plane after some finite time. In other cases, it will slip on the inclined plane. In the case of rolling, the centre of the sphere moves on a parabola. Finally the velocity and angular velocity of the sphere are exactly computed.
Study the Z-Plane Strip Capacitance
Energy Technology Data Exchange (ETDEWEB)
Parikh, H.; /Illinois U., Urbana; Swain, S.; /SLAC
2005-12-15
The BaBaR detector at the Stanford Linear Accelerator Center is currently undergoing an upgrade to improve its muon and neutral hadron detection system. The Resistive Plate Chambers (RPCs) that had been used till now have deteriorated in performance over the past few years and are being replaced by Limited Streamer Tube (LSTs). Each layer of the system consists of a set of up to 10 streamer tube modules which provide one coordinate ({phi} coordinate) and a single ''Z-plane'' which provides the Z coordinate of the hit. The large area Z-planes (up to 12m{sup 2}) are 1mm thick and contain 96 copper strips that detect the induced charge from avalanches created in the streamer tube wires. All the Z-planes needed for the upgrade have already been constructed, but only a third of the planes were installed last summer. After installing the 24 Z-planes last year, it was learned that 0.7% of the strips were dead when put inside the detector. This was mainly due to the delicate solder joint between the read-out cable and the strip, and since it is difficult to access or replace the Z-planes inside the detector, it is very important to perform various tests to make sure that the Z-planes will be efficient and effective in the long term. We measure the capacitance between the copper strips and the ground plane, and compare it to the theoretical value that we expect. Instead of measuring the capacitance channel by channel, which would be a very tedious job, we developed a more effective method of measuring the capacitance. Since all the Z-planes were built at SLAC, we also built a smaller 46 cm by 30 cm Z-plane with 12 strips just to see how they were constructed and to gain a better understanding about the solder joints.
Variable Joint Elasticities in Running
Peter, Stephan; Grimmer, Sten; Lipfert, Susanne W.; Seyfarth, Andre
In this paper we investigate how spring-like leg behavior in human running is represented at joint level. We assume linear torsion springs in the joints and between the knee and the ankle joint. Using experimental data of the leg dynamics we compute how the spring parameters (stiffness and rest angles) change during gait cycle. We found that during contact the joints reveal elasticity with strongly changing parameters and compare the changes of different parameters for different spring arrangements. The results may help to design and improve biologically inspired spring mechanisms with adjustable parameters.
Graff, Karl F
1991-01-01
This highly useful textbook presents comprehensive intermediate-level coverage of nearly all major topics of elastic wave propagation in solids. The subjects range from the elementary theory of waves and vibrations in strings to the three-dimensional theory of waves in thick plates. The book is designed not only for a wide audience of engineering students, but also as a general reference for workers in vibrations and acoustics. Chapters 1-4 cover wave motion in the simple structural shapes, namely strings, longitudinal rod motion, beams and membranes, plates and (cylindrical) shells. Chapter
Wave propagation in elastic solids
Achenbach, Jan
1984-01-01
The propagation of mechanical disturbances in solids is of interest in many branches of the physical scienses and engineering. This book aims to present an account of the theory of wave propagation in elastic solids. The material is arranged to present an exposition of the basic concepts of mechanical wave propagation within a one-dimensional setting and a discussion of formal aspects of elastodynamic theory in three dimensions, followed by chapters expounding on typical wave propagation phenomena, such as radiation, reflection, refraction, propagation in waveguides, and diffraction. The treat
Elastic Moduli of Carbon Nanohorns
Directory of Open Access Journals (Sweden)
Dinesh Kumar
2011-01-01
Full Text Available Carbon nanotube is a special case of carbon nanohorns or carbon nanocones with zero apex angle. Research into carbon nanohorns started almost at the same time as the discovery of nanotubes in 1991. Most researchers focused on the investigation of nanotubes, and the exploration of nanohorns attracted little attention. To model the carbon nanohorns, we make use of a more reliable second-generation reactive empirical bond-order potential by Brenner and coworkers. We investigate the elastic moduli and conclude that these nanohorns are equally strong and require in-depth investigation. The values of Young's and Shear moduli decrease with apex angle.
Sadeghian, H.; Goosen, J. F. L.; Bossche, A.; van Keulen, F.
2009-06-01
In this letter, the dominant role of surface stress and surface elasticity on the overall elastic behavior of ultrathin cantilever plates is studied. A general framework based on two-dimensional plane-stress analysis is presented. Because of either surface reconstruction or molecular adsorption, there exists a surface stress and a surface elasticity imbalance between top and bottom surface of the cantilever. The surface elasticity imbalance creates an extra bending-extensional coupling which has not been taken into account previously. This leads to a modified extensional stiffness, bending stiffness and bending-extensional coupling stiffness. Due to the surface stress imbalance, an extended Stoney's formula for self-bending of ultrathin cantilevers is derived.
Dudar, O. I.; Dudar, E. S.
2017-11-01
The features of application of the 1D dimensional finite element method (FEM) in combination with the laminar solutions method (LSM) for the calculation of underground ventilating networks are considered. In this case the processes of heat and mass transfer change the properties of a fluid (binary vapour-air mix). Under the action of gravitational forces it leads to such phenomena as natural draft, local circulation, etc. The FEM relations considering the action of gravity, the mass conservation law, the dependence of vapour-air mix properties on the thermodynamic parameters are derived so that it allows one to model the mentioned phenomena. The analogy of the elastic and plastic rod deformation processes to the processes of laminar and turbulent flow in a pipe is described. Owing to this analogy, the guaranteed convergence of the elastic solutions method for the materials of plastic type means the guaranteed convergence of the LSM for any regime of a turbulent flow in a rough pipe. By means of numerical experiments the convergence rate of the FEM - LSM is investigated. This convergence rate appeared much higher than the convergence rate of the Cross – Andriyashev method. Data of other authors on the convergence rate comparison for the finite element method, the Newton method and the method of gradient are provided. These data allow one to conclude that the FEM in combination with the LSM is one of the most effective methods of calculation of hydraulic and ventilating networks. The FEM - LSM has been used for creation of the research application programme package “MineClimate” allowing to calculate the microclimate parameters in the underground ventilating networks.
DEFF Research Database (Denmark)
Bergemann, Maria; Collet, Remo; Schönrich, Ralph
2016-01-01
/Fe] ratios close to solar even at [Fe/H] ~ -2. This is at variance with results of classical abundance analyses based on local thermodynamic equilibrium (LTE) and 1D model stellar atmospheres, which argue for a constant elevated [Mg/Fe] in metal-poor stars of the Galactic thick disk and halo.......We have analysed high-resolution spectra of 328 stars and derived Mg abundances using non-local thermodynamic equilibrium (NLTE) spectral line formation calculations and plane-parallel model stellar atmospheres derived from the mean stratification of 3D hydrodynamical surface convection simulations...
Biomechanical differences between incline and plane hopping.
Kannas, Theodoros M; Kellis, Eleftherios; Amiridis, Ioannis G
2011-12-01
Kannas, TM, Kellis, E, and Amiridis, IG. Biomechanical differences between incline and plane hopping. J Strength Cond Res 25(12): 3334-3341, 2011-The need for the generation of higher joint power output during performance of dynamic activities led us to investigate the force-length relationship of the plantar flexors during consecutive stretch-shortening cycles of hopping. The hypothesis of this study was that hopping (consecutive jumps with the knee as straight as possible) on an inclined (15°) surface might lead to a better jumping performance compared with hopping on a plane surface (0°). Twelve active men performed 3 sets of 10 consecutive hops on both an incline and plane surface. Ground reaction forces; ankle and knee joint kinematics; electromyographic (EMG) activity from the medial gastrocnemius (MG), soleus (Sol) and tibialis anterior (TA); and architectural data from the MG were recorded. The results showed that participants jumped significantly higher (p plane surface (27.52 ± 4.97 cm). No differences in temporal characteristics between the 2 types of jumps were observed. Incline hopping induced significantly greater ankle dorsiflexion and knee extension at takeoff compared with plane hopping (p propulsion phase were significantly higher during incline compared with that during plane hopping (p plane surface.
Directory of Open Access Journals (Sweden)
Maity N.
2017-06-01
Full Text Available The article is concernedwith the possibility of plane wave propagation in a rotating elastic medium under the action of magnetic and thermal fields. The material is assumed to be fibre-reinforced with increased stiffness, strength and load bearing capacity. Green and Nagdhi’s concepts of generalized thermoelastic models II and III have been followed in the governing equations expressed in tensor notation. The effects of various parameters of the applied fields on the plane wave velocity have been shown graphically.
Demand Elasticities for Mobile Telecommunications in Austria
Dewenter, Ralf; Haucap, Justus
2007-01-01
This paper analyses price elasticities in the Austrian market for mobile telecommunications services using data on firm specific tariffs in the period between January 1998 and March 2002. Dynamic panel data regressions are used to estimate short-run and long-run demand elasticities for business customers and for private consumers with both postpaid contracts and prepaid cards.We find that business customers have a higher elasticity of demand than private consumers, where postpaid customers te...
Active elastic metamaterials with applications in acoustics
Pope, Simon; Laalej, Hatim; Daley, Steve
2012-01-01
International audience; Elastic metamaterials provide a new approach to solving existing problems in acoustics. They have also been associated with novel concepts such as acoustic invisibility and subwavelength imaging. To be applied to many of the proposed applications a metamaterial would need to have the desired mass density and elastic moduli over a wide frequency band. To minimise scatter in acoustics applications the impedance of solid elastic metamaterials also need to be matched to th...
Einstein viscosity with fluid elasticity
Einarsson, Jonas; Yang, Mengfei; Shaqfeh, Eric S. G.
2018-01-01
We give the first correction to the suspension viscosity due to fluid elasticity for a dilute suspension of spheres in a viscoelastic medium. Our perturbation theory is valid to O (ϕ Wi2) in the particle volume fraction ϕ and the Weissenberg number Wi =γ ˙λ , where γ ˙ is the typical magnitude of the suspension velocity gradient, and λ is the relaxation time of the viscoelastic fluid. For shear flow we find that the suspension shear-thickens due to elastic stretching in strain "hot spots" near the particle, despite the fact that the stress inside the particles decreases relative to the Newtonian case. We thus argue that it is crucial to correctly model the extensional rheology of the suspending medium to predict the shear rheology of the suspension. For uniaxial extensional flow we correct existing results at O (ϕ Wi ) , and find dramatic strain-rate thickening at O (ϕ Wi2) . We validate our theory with fully resolved numerical simulations.
Elegent -- an elastic event generator
Kašpar, Jan
2014-01-01
Although elastic scattering of nucleons may look like a simple process, it presents a long-lasting challenge for theory. Due to missing hard energy scale, the perturbative QCD can not be applied. Instead, many phenomenological/theoretical models have emerged. In this paper we present a unified implementation of some of the most prominent models in a C++ library, moreover extended to account for effects of the electromagnetic interaction. The library is complemented with a number of utilities. For instance, programs to sample many distributions of interest in four-momentum transfer squared, t, impact parameter, b, and collision energy sqrt(s). These distributions at ISR, SppS, RHIC, Tevatron and LHC energies are available for download from the project web site. Both in the form of ROOT files and PDF figures providing comparisons among the models. The package includes also a tool for Monte-Carlo generation of elastic scattering events, which can easily be embedded in any other program framework.
Yosano, Akira; Katakura, Akira; Takaki, Takashi; Shibahara, Takahiko
2009-05-01
In this study, we investigated how method of mandibular fixation influenced longterm postoperative stability of the maxilla in Class III cases. In particular, we investigated change in the maxillary occlusal plane after Occlusal Plane Alteration. Therefore, we focused on change in the palatal plane to evaluate stability of the maxillary occlusal plane, as the position of the palatal plane affects the maxillary occlusal plane. This study included 16 patients diagnosed with mandibular protrusion. Alteration of the occlusal plane was achieved by clockwise rotation of the maxilla by Le Fort I osteotomy and mandibular setback was performed by bilateral sagittal split ramus osteotomy. We analyzed and examined lateral cephalometric radiographs taken at 1 month, 3 months, 6 months, and 1 year after surgery. Stability achieved by two methods of mandibular fixation was compared. In one group of patients (group S) titanium screws were used, and in the other group (group P) titanium-locking mini-plates were used. No significant displacement was recognized in group S, whereas an approximately 0.7mm upward vertical displacement was recognized in the anterior nasal spine in group P. As a result, not only the angle of the palatal plane and S-N plane, but also occlusal plane angle in group P showed a greater decrease than that in group S. The results suggest that fixing the mandible with screws yielded greater stability of the maxilla and maxillary occlusal plane than fixing the mandible with titanium plates.
Geometry of the plane Cremona maps
Alberich-Carramiñana, Maria
2002-01-01
This book provides a self-contained exposition of the theory of plane Cremona maps, reviewing the classical theory. The book updates, correctly proves and generalises a number of classical results by allowing any configuration of singularities for the base points of the plane Cremona maps. It also presents some material which has only appeared in research papers and includes new, previously unpublished results. This book will be useful as a reference text for any researcher who is interested in the topic of plane birational maps.
Faraday wave lattice as an elastic metamaterial
Domino, L; Patinet, Sylvain; Eddi, A
2016-01-01
Metamaterials enable the emergence of novel physical properties due to the existence of an underlying sub-wavelength structure. Here, we use the Faraday instability to shape the fluid-air interface with a regular pattern. This pattern undergoes an oscillating secondary instability and exhibits spontaneous vibrations that are analogous to transverse elastic waves. By locally forcing these waves, we fully characterize their dispersion relation and show that a Faraday pattern presents an effective shear elasticity. We propose a physical mechanism combining surface tension with the Faraday structured interface that quantitatively predicts the elastic wave phase speed, revealing that the liquid interface behaves as an elastic metamaterial.
Faraday wave lattice as an elastic metamaterial.
Domino, L; Tarpin, M; Patinet, S; Eddi, A
2016-05-01
Metamaterials enable the emergence of novel physical properties due to the existence of an underlying subwavelength structure. Here, we use the Faraday instability to shape the fluid-air interface with a regular pattern. This pattern undergoes an oscillating secondary instability and exhibits spontaneous vibrations that are analogous to transverse elastic waves. By locally forcing these waves, we fully characterize their dispersion relation and show that a Faraday pattern presents an effective shear elasticity. We propose a physical mechanism combining surface tension with the Faraday structured interface that quantitatively predicts the elastic wave phase speed, revealing that the liquid interface behaves as an elastic metamaterial.
Engineering 1D Quantum Stripes from Superlattices of 2D Layered Materials.
Gruenewald, John H; Kim, Jungho; Kim, Heung Sik; Johnson, Jared M; Hwang, Jinwoo; Souri, Maryam; Terzic, Jasminka; Chang, Seo Hyoung; Said, Ayman; Brill, Joseph W; Cao, Gang; Kee, Hae-Young; Seo, Sung S Ambrose
2017-01-01
Dimensional tunability from two dimensions to one dimension is demonstrated for the first time using an artificial superlattice method in synthesizing 1D stripes from 2D layered materials. The 1D confinement of layered Sr 2 IrO 4 induces distinct 1D quantum-confined electronic states, as observed from optical spectroscopy and resonant inelastic X-ray scattering. This 1D superlattice approach is generalizable to a wide range of layered materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack
Energy Technology Data Exchange (ETDEWEB)
Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
2017-01-24
This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.
Directory of Open Access Journals (Sweden)
Szeptyński P.
2017-06-01
Full Text Available A general proposition of an energy-based limit condition for anisotropic materials exhibiting strength-differential effect (SDE based on spectral decomposition of elasticity tensors and the use of scaling pressure-dependent functions is specified for the case of orthotropic materials. A detailed algorithm (based on classical solutions of cubic equations for the determination of elastic eigenstates and eigenvalues of the orthotropic stiffness tensor is presented. A yield condition is formulated for both two-dimensional and three-dimensional cases. Explicit formulas based on simple strength tests are derived for parameters of criterion in the plane case. The application of both criteria for the description of yielding and plastic deformation of metal sheets is discussed in detail. The plane case criterion is verified with experimental results from the literature.
Lawton, Anna P; Prigozy, Theodore I; Brossay, Laurent; Pei, Bo; Khurana, Archana; Martin, Donald; Zhu, Tiancheng; Späte, Kira; Ozga, Megda; Höning, Stefan; Bakke, Oddmund; Kronenberg, Mitchell
2005-03-15
The short cytoplasmic tail of mouse CD1d (mCD1d) is required for its endosomal localization, for the presentation of some glycolipid Ags, and for the development of Valpha14i NKT cells. This tail has a four-amino acid Tyr-containing motif, Tyr-Gln-Asp-Ile (YQDI), similar to those sequences known to be important for the interaction with adaptor protein complexes (AP) that mediate the endosomal localization of many different proteins. In fact, mCD1d has been shown previously to interact with the AP-3 adaptor complex. In the present study, we mutated each amino acid in the YQDI motif to determine the importance of the entire motif sequence in influencing mCD1d trafficking, its interaction with adaptors, and its intracellular localization. The results indicate that the Y, D, and I amino acids are significant functionally because mutations at each of these positions altered the intracellular distribution of mCD1d and reduced its ability to present glycosphingolipids to NKT cells. However, the three amino acids are not all acting in the same way because they differ with regard to how they influence the intracellular distribution of CD1d, its rate of internalization, and its ability to interact with the mu subunit of AP-3. Our results emphasize that multiple steps, including interactions with the adaptors AP-2 and AP-3, are required for normal trafficking of mCD1d and that these different steps are mediated by only a few cytoplasmic amino acids.
Kim, Taeyong; Ding, Ding; Yim, Jong-Hyuk; Jho, Young-Dahl; Minnich, Austin J.
2017-08-01
Molybdenum disulfide (MoS2), a member of transition-metal dichalcogenide family, is of intense interest due to its unique electronic and thermoelectric properties. However, reports of its in-plane thermal conductivity vary due to the difficulty of in-plane thermal conductivity measurements on thin films, and an experimental measurement of the in-plane sound velocity has not been reported. Here, we use time-resolved transient grating spectroscopy to simultaneously measure the in-plane elastic and thermal properties of free-standing MoS2 membranes at room temperature. We obtain a longitudinal acoustic phonon velocity of 7000 ± 40 m s-1 and an in-plane thermal conductivity of 74 ± 21 W m-1K-1. Our measurements provide useful insights into the elastic and thermal properties of MoS2 and demonstrate the capability of transient grating spectroscopy to investigate the in-plane vibrational properties of van der Waals materials that are challenging to characterize with conventional methods.
Directory of Open Access Journals (Sweden)
Taeyong Kim
2017-08-01
Full Text Available Molybdenum disulfide (MoS2, a member of transition-metal dichalcogenide family, is of intense interest due to its unique electronic and thermoelectric properties. However, reports of its in-plane thermal conductivity vary due to the difficulty of in-plane thermal conductivity measurements on thin films, and an experimental measurement of the in-plane sound velocity has not been reported. Here, we use time-resolved transient grating spectroscopy to simultaneously measure the in-plane elastic and thermal properties of free-standing MoS2 membranes at room temperature. We obtain a longitudinal acoustic phonon velocity of 7000 ± 40 m s−1 and an in-plane thermal conductivity of 74 ± 21 W m−1K−1. Our measurements provide useful insights into the elastic and thermal properties of MoS2 and demonstrate the capability of transient grating spectroscopy to investigate the in-plane vibrational properties of van der Waals materials that are challenging to characterize with conventional methods.
Calculation of exact vibration modes for plane grillages by the dynamic stiffness method
Hallauer, W. L., Jr.; Liu, R. Y. L.
1982-01-01
A dynamic stiffness method is developed for the calculation of the exact modal parameters for plane grillages which consist of straight and uniform beams with coincident elastic and inertial axes. Elementary bending-torsion beam theory is utilized, and bending translation is restricted to one direction. The exact bending-torsion dynamic stiffness matrix is obtained for a straight and uniform beam element with coincident elastic and inertial axes. The element stiffness matrices are assembled using the standard procedure of the static stiffness method to form the dynamic stiffness matrix of the complete grillage. The exact natural frequencies, mode shapes, and generalized masses of the grillage are then calculated by solving a nonlinear eigenvalue problem based on the dynamic stiffness matrix. The exact modal solutions for an example grillage are calculated and compared with the approximate solutions obtained by using the finite element method.
Xu, Xing-Wang; Peters, Stephen; Liang, Guang-He; Zhang, Bao-Lin
2016-01-01
We report on a new mechanical principle, which suggests that a confined liquid in the elastic lithosphere has the potential to transmit a maximum applied compressive stress. This stress can be transmitted to the internal contacts between rock and liquid and would then be transformed into a normal compressive stress with tangential tensile stress components. During this process, both effective compressive normal stress and tensile tangential stresses arise along the liquid–rock contact. The minimum effective tensile tangential stress causes the surrounding rock to rupture. Liquid-driven fracture initiates at the point along the rock–liquid boundary where the maximum compressive stress is applied and propagates along a plane that is perpendicular to the minimum effective tensile tangential stress and also is perpendicular to the minimum principal stress.
Titanium Heat Pipe Thermal Plane Project
National Aeronautics and Space Administration — The objective of the Phase II program is to complete the development of the titanium heat pipe thermal plane and establish all necessary steps for production of this...
Large Format Uncooled Focal Plane Array Project
National Aeronautics and Space Administration — Uncooled focal plane arrays have improved dramatically and array sizes of 320x240 elements in a 50-?m pitch are commercially available at affordable cost. Black...
Titanium Heat Pipe Thermal Plane Project
National Aeronautics and Space Administration — Thermacore Inc. proposes an innovative titanium heat pipe thermal plane for passive thermal control of individual cells within a fuel cell stack. The proposed...
Causal inheritence in plane wave quotients
Energy Technology Data Exchange (ETDEWEB)
Hubeny, Veronika E.; Rangamani, Mukund; Ross, Simon F.
2003-11-24
We investigate the appearance of closed timelike curves in quotients of plane waves along spacelike isometries. First we formulate a necessary and sufficient condition for a quotient of a general spacetime to preserve stable causality. We explicitly show that the plane waves are stably causal; in passing, we observe that some pp-waves are not even distinguishing. We then consider the classification of all quotients of the maximally supersymmetric ten-dimensional plane wave under a spacelike isometry, and show that the quotient will lead to closed timelike curves iff the isometry involves a translation along the u direction. The appearance of these closed timelike curves is thus connected to the special properties of the light cones in plane wave spacetimes. We show that all other quotients preserve stable causality.
Elastic Wave Radiation from a Line Source of Finite Length
Energy Technology Data Exchange (ETDEWEB)
Aldridge, D.F.
1998-11-04
Straightforward algebraic expressions describing the elastic wavefield produced by a line source of finite length are derived in circular cylindrical coordinates. The surrounding elastic medium is assumed to be both homogeneous and isotropic, anc[ the source stress distribution is considered axisymmetic. The time- and space-domain formulae are accurate at all distances and directions from the source; no fa-field or long-wavelength assumptions are adopted for the derivation. The mathematics yield a unified treatment of three different types of sources: an axial torque, an axial force, and a radial pressure. The torque source radiates only azirnuthally polarized shear waves, whereas force and pressure sources generate simultaneous compressional and shear radiation polarized in planes containing the line source. The formulae reduce to more familiar expressions in the two limiting cases where the length of the line source approaches zero and infinity. Far-field approximations to the exact equations indicate that waves radiated parallel to the line source axI.s are attenuated relative to those radiated normal to the axis. The attenuation is more severe for higher I?equencies and for lower wavespeeds. Hence, shear waves are affected more than compressional waves. This fi-equency- and directiondependent attenuation is characterized by an extremely simple mathematical formula, and is readily apparent in example synthetic seismograms.
Shaganov, Igor I; Perova, Tatiana S; Moore, R Alan; Berwick, Kevin
2005-05-26
The spectral properties of composite materials based on small particles under 1D, 2D, and 3D size confinement are described using a combination of dispersive internal field and effective media theory approaches. Calculations performed for a number of crystalline materials have shown that the peak position and intensity of the vibrational band of the material under conditions of 1D, 2D, and 3D size confinement are changed, whereas the bandwidth of the band remains the same. In the case of 3D confinement, the peak position of the spectrum of isolated "mesoparticles" (epsilon(meso)(2)) appears to be very close to the intrinsic frequency of the lattice vibrations, calculated from the elastic constants of this crystal, as well as to the Fröhlich's frequency. The largest shift (Deltanu) of the peak frequency, nu(max), from the bulk value is obtained in the case of 1D confinement when the peak position is practically coincident with the frequency of the longitudinal optical phonon (nu(LO)). These shifts are the result of intermolecular interactions, including both resonant and induced resonant dipole-dipole interactions.
Phase stability and elastic properties of Cr-V alloys
Energy Technology Data Exchange (ETDEWEB)
Gao, M C; Suzuki, Y; Schweiger, H; Doğan, Ö N; Hawk, J; Widom, M
2013-01-23
V is the only element in the periodic table that forms a complete solid solution with Cr and thus is particularly important in alloying strategy to ductilize Cr. This study combines first-principles density functional theory calculations and experiments to investigate the phase stability and elastic properties of Cr–V binary alloys. The cluster expansion study reveals the formation of various ordered compounds at low temperatures that were not previously known. These compounds become unstable due to the configurational entropy of bcc solid solution as the temperature is increased. The elastic constants of ordered and disordered compounds are calculated at both T = 0 K and finite temperatures. The overall trends in elastic properties are in agreement with measurements using the resonant ultrasound spectroscopy method. The calculations predict that addition of V to Cr decreases both the bulk modulus and the shear modulus, and enhances the Poisson’s ratio, in agreement with experiments. Decrease in the bulk modulus is correlated to decrease in the valence electron density and increase in the lattice constant. An enhanced Poisson’s ratio for bcc Cr–V alloys (compared to pure Cr) is associated with an increased density of states at the Fermi level. Furthermore, the difference charge density in the bonding region in the (110) slip plane is highest for pure Cr and decreases gradually as V is added. The present calculation also predicts a negative Cauchy pressure for pure Cr, and it becomes positive upon alloying with V. The intrinsic ductilizing effect from V may contribute, at least partially, to the experimentally observed ductilizing phenomenon in the literature.
Energy Technology Data Exchange (ETDEWEB)
Ozaki, N.; Lappalainen, J.; Linnoila, M. [National Institute on Alcohol Abuse and Alcoholism, Rockville, MD (United States)] [and others
1995-04-24
Serotonin (5-HT){sub ID} receptors are 5-HT release-regulating autoreceptors in the human brain. Abnormalities in brain 5-HT function have been hypothesized in the pathophysiology of various psychiatric disorders, including obsessive-compulsive disorder, autism, mood disorders, eating disorders, impulsive violent behavior, and alcoholism. Thus, mutations occurring in 5-HT autoreceptors may cause or increase the vulnerability to any of these conditions. 5-HT{sub 1D{alpha}} and 5-HT{sub 1D{Beta}} subtypes have been previously localized to chromosomes 1p36.3-p34.3 and 6q13, respectively, using rodent-human hybrids and in situ localization. In this communication, we report the detection of a 5-HT{sub 1D{alpha}} receptor gene polymorphism by single strand conformation polymorphism (SSCP) analysis of the coding sequence. The polymorphism was used for fine scale linkage mapping of 5-HT{sub 1D{alpha}} on chromosome 1. This polymorphism should also be useful for linkage studies in populations and in families. Our analysis also demonstrates that functionally significant coding sequence variants of the 5-HT{sub 1D{alpha}} are probably not abundant either among alcoholics or in the general population. 14 refs., 1 fig., 1 tab.
Slip patterns and preferred dislocation boundary planes
DEFF Research Database (Denmark)
Winther, G.
2003-01-01
The planes of deformation induced extended planar dislocation boundaries are analysed in two different co-ordinate systems, namely the macroscopic system defined by the deformation axes and the crystallographic system given by the crystallographic lattice. The analysis covers single and polycryst......The planes of deformation induced extended planar dislocation boundaries are analysed in two different co-ordinate systems, namely the macroscopic system defined by the deformation axes and the crystallographic system given by the crystallographic lattice. The analysis covers single...
Attitude analysis in Flatland: The plane truth
Shuster, Malcolm D.
1993-01-01
Many results in attitude analysis are still meaningful when the attitude is restricted to rotations about a single axis. Such a picture corresponds to attitude analysis in the Euclidean plane. The present report formalizes the representation of attitude in the plane and applies it to some well-known problems. In particular, we study the connection of the 'additive' and 'multiplicative' formulations of the differential corrector for the quaternion in its two-dimensional setting.
Carroll symmetry of plane gravitational waves
Duval, C.; Gibbons, G W; Horvathy, P. A.; Zhang, P. -M.
2017-01-01
The well-known 5-parameter isometry group of plane gravitational waves in $4$ dimensions is identified as Levy-Leblond's Carroll group in $2+1$ dimensions with no rotations. Our clue is that plane waves are Bargmann spaces into which Carroll manifolds can be embedded. We also comment on the scattering of light by a gravitational wave and calculate its electric permittivity considered as an impedance-matched metamaterial.
Large Focal Plane Arrays for Future Missions
Scowen, Paul A.; Nikzad, Shouleh; Hoenk, Michael; Gontijo, Ivair; Shapiro, Andrew; Greer, Frank; Jones, Todd; Seshadri, Suresh; Jacquot, Blake; Monacos, Steve; Lisman, Doug; Dickie, Matthew; Blacksberg, Jordana
2009-01-01
We outline the challenges associated with the development and construction of large focal plane arrays for use both on the ground and in space. Using lessons learned from existing JPL-led and ASU/JPL partnership efforts to develop technology for, and design such arrays and imagers for large focal planes, we enumerate here the remaining problems that need to be solved to make such a venture viable. Technologies we consider vital for further development include: (1) architectures, processes, ci...
Cell visco-elasticity measured with AFM and optical trapping at sub-micrometer deformations.
Directory of Open Access Journals (Sweden)
Schanila Nawaz
Full Text Available The measurement of the elastic properties of cells is widely used as an indicator for cellular changes during differentiation, upon drug treatment, or resulting from the interaction with the supporting matrix. Elasticity is routinely quantified by indenting the cell with a probe of an AFM while applying nano-Newton forces. Because the resulting deformations are in the micrometer range, the measurements will be affected by the finite thickness of the cell, viscous effects and even cell damage induced by the experiment itself. Here, we have analyzed the response of single 3T3 fibroblasts that were indented with a micrometer-sized bead attached to an AFM cantilever at forces from 30-600 pN, resulting in indentations ranging from 0.2 to 1.2 micrometer. To investigate the cellular response at lower forces up to 10 pN, we developed an optical trap to indent the cell in vertical direction, normal to the plane of the coverslip. Deformations of up to two hundred nanometers achieved at forces of up to 30 pN showed a reversible, thus truly elastic response that was independent on the rate of deformation. We found that at such small deformations, the elastic modulus of 100 Pa is largely determined by the presence of the actin cortex. At higher indentations, viscous effects led to an increase of the apparent elastic modulus. This viscous contribution that followed a weak power law, increased at larger cell indentations. Both AFM and optical trapping indentation experiments give consistent results for the cell elasticity. Optical trapping has the benefit of a lower force noise, which allows a more accurate determination of the absolute indentation. The combination of both techniques allows the investigation of single cells at small and large indentations and enables the separation of their viscous and elastic components.
Elasticity of the Coracohumeral Ligament in Patients with Adhesive Capsulitis of the Shoulder.
Wu, Chueh-Hung; Chen, Wen-Shiang; Wang, Tyng-Guey
2016-02-01
To evaluate the elasticity of the coracohumeral ligament (CHL) in healthy individuals and patients with clinical findings suggestive of unilaterally involved adhesive capsulitis of the shoulder (ACS). The institutional review board approved this single-institution prospective study, which was performed between November 15, 2012, and July 8, 2014. Informed consent was obtained from all subjects. Measurement of CHL thickness was performed in the axial oblique plane under shoulder maximal external rotation. Shear-wave elastography (SWE) was used to evaluate elasticity of the CHL in healthy individuals (11 men, 19 women aged 22-62 years) and those with clinical findings suggestive of ACS (nine men, 11 women aged 41-70 years). SWE was performed in the shoulder-neutral position and under maximal external rotation. The Wilcoxon signed-rank test was performed to compare the thickness and elastic modulus of the CHL between bilateral shoulders. In all subjects, the CHL elastic modulus was larger under maximal external rotation than in the neutral position (P elastic modulus between the dominant and nondominant shoulders. For patients presumed to have ACS, the CHL thickness was significantly greater in the symptomatic shoulder than in the unaffected shoulder (P elastic modulus of the symptomatic shoulder (median, 234.8 kPa; interquartile range [IQR], 174.4-256.7 kPa) was significantly greater than that of the unaffected shoulder (median, 203.3 kPa; IQR, 144.1-242.7 kPa) in the shoulder-neutral position (P = .004) but not under maximal external rotation (P = .123). When bilateral shoulders were maintained at the same angle of external rotation, the CHL elastic modulus was greater in the symptomatic shoulder than in the unaffected shoulder (P = .005). In patients with clinical findings suggestive of ACS, SWE showed that the CHL is stiffer in the symptomatic shoulder than in the unaffected shoulder. © RSNA, 2015.
The Zwicky Transient Facility Galactic Plane Survey
Prince, Thomas; Zwicky Transient Facility (ZTF) Project Team
2018-01-01
The Zwicky Transient Faciility (ZTF) is a new survey camera mounted on the 1.2m Oschin Schmidt Telescope on Mount Palomar. The camera has a 47 square degree field of view and is expected to start public survey observations in early 2018. The public surveys are undertaken with support provided by the NSF MSIP program. One of the two public surveys is a twice nightly scan of the central Galactic Plane visible from Mount Palomar, one scan in r-band and one in g-band. Publicly accessible data from the survey will be one of two types: (1) prompt alerts of variable activity of Galactic Plane sources using image difference source identification, and (2) photometric light curves of Galactic Plane sources extracted from calibrated images. Data will be made accessible through the Caltech Image Processing and Analysis Center (IPAC). The ZTF Galactic Plane Survey, combined with Gaia and PanSTARRS data, will be an exciting new resource for time domain astronomy observations of Galactic sources.We will describe the details of the ZTF Galactic Plane survey, including estimated coverage of the plane and light curve sampling. We will also describe plans for public access to the data, as well as comment on some of the important science that will be possible using the survey data.
Deep plane facelifting for facial rejuvenation.
Gordon, Neil; Adam, Stewart
2014-08-01
The purpose of this article is to provide the facial plastic surgeon with anatomical and embryologic evidence to support the use of the deep plane technique for optimal treatment of facial aging. A detailed description of the procedure is provided to allow safe and consistent performance. Insights into anatomical landmarks, technical nuances, and alternative approaches for facial variations are presented. The following points will be further elucidated in the article. The platysma muscle/submuscular aponeurotic system/galea are the continuous superficial cervical fascia encompassing the majority of facial fat, and this superficial soft tissue envelope is poorly anchored to the face. The deep cervical fascia binds the structural aspects of the face and covers the facial nerve and buccal fat pad. Facial aging is mainly due to gravity's long-term effects on the superficial soft tissue envelope, with more subtle effects on the deeper structural compartments. The deep plane is the embryologic cleavage plane between these fascial layers, and is the logical place for facial dissection. The deep plane allows access to the buccal fat pad for treatment of jowling. Soft tissue mobilization is maximized in deep plane dissections and requires careful hairline planning. Flap advancement creates tension only at the fascia level allowing natural, tension-free skin closure, and long-lasting outcomes. The deep plane advancement flap is well vascularized and resistant to complications. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.
Mathematical methods for elastic plates
Constanda, Christian
2014-01-01
Mathematical models of deformation of elastic plates are used by applied mathematicians and engineers in connection with a wide range of practical applications, from microchip production to the construction of skyscrapers and aircraft. This book employs two important analytic techniques to solve the fundamental boundary value problems for the theory of plates with transverse shear deformation, which offers a more complete picture of the physical process of bending than Kirchhoff’s classical one. The first method transfers the ellipticity of the governing system to the boundary, leading to singular integral equations on the contour of the domain. These equations, established on the basis of the properties of suitable layer potentials, are then solved in spaces of smooth (Hölder continuous and Hölder continuously differentiable) functions. The second technique rewrites the differential system in terms of complex variables and fully integrates it, expressing the solution as a combination of complex ana...
Multidiscipline simulation of elastic manipulators
Directory of Open Access Journals (Sweden)
T. Rølvåg
1992-10-01
Full Text Available This paper contributes to multidiscipline simulation of elastic robot manipulators in FEDEM. All developments presented in this paper are based on the formulations in FEDEM, a simulation system developed by the authors which combines finite element, mechanism and control analysis. In order to establish this general simulation system as an efficient multidiscipline robot design tool a robot control system including a high level robot programming language, interpolation algorithms, path generation algorithms, forward and inverse kinematics, control systems, gear and transmission models are implemented. These new features provide a high level of integration between traditionally separate design disciplines from the very beginning of the design and optimization process. Several simulations have shown that high fidelity mathematical models can be derived and used as a basis for dynamic analysis and controller design in FEDEM.
Wrinkling of Pressurized Elastic Shells
Vella, Dominic; Ajdari, Amin; Vaziri, Ashkan; Boudaoud, Arezki
2011-10-01
We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the number of wrinkles formed in terms of the internal pressurization and material properties of the shell. These results are validated by numerical simulations. We show that the evolution of the wrinkle length with increasing indentation can be understood for highly pressurized shells from membrane theory. These results suggest that the position and number of wrinkles may be used in combination to give simple methods for the estimation of the mechanical properties of highly pressurized shells.
Wrinkling of Pressurized Elastic Shells
Vella, Dominic
2011-10-01
We study the formation of localized structures formed by the point loading of an internally pressurized elastic shell. While unpressurized shells (such as a ping-pong ball) buckle into polygonal structures, we show that pressurized shells are subject to a wrinkling instability. We study wrinkling in depth, presenting scaling laws for the critical indentation at which wrinkling occurs and the number of wrinkles formed in terms of the internal pressurization and material properties of the shell. These results are validated by numerical simulations. We show that the evolution of the wrinkle length with increasing indentation can be understood for highly pressurized shells from membrane theory. These results suggest that the position and number of wrinkles may be used in combination to give simple methods for the estimation of the mechanical properties of highly pressurized shells. © 2011 American Physical Society.
Elastic modulus of hard tissues.
Bar-On, Benny; Wagner, H Daniel
2012-02-23
This work aims at evaluating the elastic modulus of hard biological tissues by considering their staggered platelet micro-structure. An analytical expression for the effective modulus along the stagger direction is formulated using three non-dimensional structural variables. Structures with a single staggered hierarchy (e.g. collagen fibril) are first studied and predictions are compared with the experimental results and finite element simulations from the literature. A more complicated configuration, such as an array of fibrils, is analyzed next. Finally, a mechanical model is proposed for tooth dentin, in which variations in the multi-scale structural hierarchy are shown to significantly affect the macroscopic mechanical properties. Copyright © 2011 Elsevier Ltd. All rights reserved.
Optimization Of Elastic Bridge Trusses
Directory of Open Access Journals (Sweden)
Ignas Rimkus
2013-12-01
Full Text Available The article analyzes the problems of optimizing elastic bridgetrusses, which is a tool for seeking the establishment of theminimum volume (mass of construction and optimization of thecross-section area and height as well as the structure of the truss.It has been formulated as a nonlinear discrete mathematical programmingproblem. The upper band of the truss works not onlyfor compression but also for bending. The cross-sections of theelements are designed from rolled steel sections. Mathematicalmodels are prepared by using the finite element method and complyingwith requirements for the strength, stiffness and stabilityof the structure. The formulated problems are solved referringto an iterative process and applying the mathematical softwarepackage “MATLAB” along with routine “fmincon”. The ratio ofbuckling is corrected in every case of iteration. Requirementsfor cross-section assortment (discretion are fulfilled employingthe branch and bound method.
High elastic modulus polymer electrolytes
Balsara, Nitash Pervez; Singh, Mohit; Eitouni, Hany Basam; Gomez, Enrique Daniel
2013-10-22
A polymer that combines high ionic conductivity with the structural properties required for Li electrode stability is useful as a solid phase electrolyte for high energy density, high cycle life batteries that do not suffer from failures due to side reactions and dendrite growth on the Li electrodes, and other potential applications. The polymer electrolyte includes a linear block copolymer having a conductive linear polymer block with a molecular weight of at least 5000 Daltons, a structural linear polymer block with an elastic modulus in excess of 1.times.10.sup.7 Pa and an ionic conductivity of at least 1.times.10.sup.-5 Scm.sup.-1. The electrolyte is made under dry conditions to achieve the noted characteristics.
Reversible simulations of elastic collisions
Energy Technology Data Exchange (ETDEWEB)
Perumalla, Kalyan S.; Protopopescu, Vladimir A.
2013-05-01
Consider a system of N identical hard spherical particles moving in a d-dimensional box and undergoing elastic, possibly multi-particle, collisions. We develop a new algorithm that recovers the pre-collision state from the post-collision state of the system, across a series of consecutive collisions, \\textit{with essentially no memory overhead}. The challenge in achieving reversibility for an n-particle collision (where, in general, n<< N) arises from the presence of nd-d-1 degrees of freedom (arbitrary angles) during each collision, as well as from the complex geometrical constraints placed on the colliding particles. To reverse the collisions in a traditional simulation setting, all of the particular realizations of these degrees of freedom (angles) during the forward simulation must be tracked. This requires memory proportional to the number of collisions, which grows very fast with N and d, thereby severely limiting the \\textit{de facto} applicability of the scheme. This limitation is addressed here by first performing a pseudo-randomization of angles, which ensures determinism in the reverse path for any values of n and d. To address the more difficult problem of geometrical and dynamic constraints, a new approach is developed which correctly samples the constrained phase space. Upon combining the pseudo-randomization with correct phase space sampling, perfect reversibility of collisions is achieved, as illustrated for n<=3, d=2, and n=2, d=3. This result enables, for the first time, reversible simulations of elastic collisions with essentially zero memory accumulation. In principle, the approach presented here could be generalized to larger values of n, which would be of definite interest for molecular dynamics simulations at high densities.
Ramanna, J.; Yedukondalu, N.; Ramesh Babu, K.; Vaitheeswaran, G.
2013-06-01
We report the structural, elastic, electronic, and optical properties of antiperovskite alkali metal oxyhalides Na3OCl, Na3OBr, and K3OBr using two different density functional methods within generalized gradient approximation (GGA). Plane wave pseudo potential (PW-PP) method has been used to calculate the ground state structural and elastic properties while the electronic structure and optical properties are calculated explicitly using full potential-linearized augmented plane wave (FP-LAPW) method. The calculated ground state properties of the investigated compounds agree quite well with the available experimental data. The predicted elastic constants using both PW-PP and FP-LAPW methods are in good accord with each other and show that the materials are mechanically stable. The low values of the elastic moduli indicate that these materials are soft in nature. The bulk properties such as shear moduli, Young's moduli, and Poisson's ratio are derived from the calculated elastic constants. Tran-Blaha modified Becke-Johnson (TB-mBJ) potential improves the band gaps over GGA and Engel-Vosko GGA. The computed TB-mBJ electronic band structure reveals that these materials are direct band gap insulators. The complex dielectric function of the metal oxyhalide compounds have been calculated and the observed prominent peaks are analyzed through the TB-mBJ electronic structures. By using the knowledge of complex dielectric function other important optical properties including absorption, reflectivity, refractive index and loss function have been obtained as a function of energy.
Evaluation of Antenna Foundation Elastic Modulus
Mcginness, H.; Anderson, G.
1983-01-01
An experiment to measure the elastic deflection of the DSS 14 concrete pedestal under the weight of the antenna was conducted in February 1983 and is compared to a similiar experiment made in 1968. Comparison of the results confirms the decrease in elastic modulus measured on core samples recently taken from the pedestal.
Modulography: elasticity imaging of atherosclerotic plaques
R. Baldewsing (Radj)
2006-01-01
textabstractModulography is an experimental elasticity imaging method. It has potential to become an all-in-one in vivo tool (a) for detecting vulnerable atherosclerotic coronary plaques, (b) for assessing information related to their rupture-proneness and (c) for imaging their elastic material
Elastic moduli of nearly pure polycrystalline plutonium
Migliori, Albert; Shekhter, Arkady; Betts, Jon B.; Fanelli, Victor
2012-02-01
We measure elastic moduli of microalloyed poly-crystalline cylindrical specimen of Pu-239. We observe α->β->γ->δ phase transitions and find that the elastic moduli of nearly pure plutonium are the same as those of Ga-stabilized plutonium.
Wave propagation in elastic layers with damping
DEFF Research Database (Denmark)
Sorokin, Sergey; Darula, Radoslav
2016-01-01
The conventional concepts of a loss factor and complex-valued elastic moduli are used to study wave attenuation in a visco-elastic layer. The hierarchy of reduced-order models is employed to assess attenuation levels in various situations. For the forcing problem, the attenuation levels are found...
Vibrations of a pipe on elastic foundations
Indian Academy of Sciences (India)
R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22
is investigated. Two cases of elastic foundations are considered: rotational and both linear and rotational. The major findings are the variations in frequency with flow velocity and displacements at different points and times. Keywords. Cantilevered pipe; vibrations of pipes; elastic foundations; exter- nal transverse force. 1.
Elastic least-squares reverse time migration
Feng, Zongcai
2017-03-08
We use elastic least-squares reverse time migration (LSRTM) to invert for the reflectivity images of P- and S-wave impedances. Elastic LSRTMsolves the linearized elastic-wave equations for forward modeling and the adjoint equations for backpropagating the residual wavefield at each iteration. Numerical tests on synthetic data and field data reveal the advantages of elastic LSRTM over elastic reverse time migration (RTM) and acoustic LSRTM. For our examples, the elastic LSRTM images have better resolution and amplitude balancing, fewer artifacts, and less crosstalk compared with the elastic RTM images. The images are also better focused and have better reflector continuity for steeply dipping events compared to the acoustic LSRTM images. Similar to conventional leastsquares migration, elastic LSRTM also requires an accurate estimation of the P- and S-wave migration velocity models. However, the problem remains that, when there are moderate errors in the velocity model and strong multiples, LSRTMwill produce migration noise stronger than that seen in the RTM images.
Elasticity of a quantum monolayer solid
DEFF Research Database (Denmark)
Bruch, Ludwig Walter
1992-01-01
A perturbation-theory formulation of the zero-temperature elastic constants is used to verify symmetry relations for a (monolayer) triangluar lattice. A generalization of the Cauchy relation between the two elastic constants of the triangular lattice with central-pair-potential interactions...
If d is super-metric, then d/(1+d) is super-metric
Warrens, Matthijs
2017-01-01
If a function d is metric, a well-known result is that d/(1 + d) is also metric. We consider m-ary analogs of the binary notion of semimetric, called hemi-metrics and super-metrics. The metrics are totally symmetric maps from Xm+1 into R≥0. It is shown that, if d is supermetric, then d/(1 + d) is
The FLO Diffusive 1D-2D Model for Simulation of River Flooding
Directory of Open Access Journals (Sweden)
Costanza Aricò
2016-05-01
Full Text Available An integrated 1D-2D model for the solution of the diffusive approximation of the shallow water equations, named FLO, is proposed in the present paper. Governing equations are solved using the MArching in Space and Time (MAST approach. The 2D floodplain domain is discretized using a triangular mesh, and standard river sections are used for modeling 1D flow inside the section width occurring with low or standard discharges. 1D elements, inside the 1D domain, are quadrilaterals bounded by the trace of two consecutive sections and by the sides connecting their extreme points. The water level is assumed to vary linearly inside each quadrilateral along the flow direction, but to remain constant along the direction normal to the flow. The computational cell can share zero, one or two nodes with triangles of the 2D domain when lateral coupling occurs and more than two nodes in the case of frontal coupling, if the corresponding section is at one end of the 1D channel. No boundary condition at the transition between the 1D-2D domain has to be solved, and no additional variable has to be introduced. Discontinuities arising between 1D and 2D domains at 1D sections with a top width smaller than the trace of the section are properly solved without any special restriction on the time step.
Analytical solutions for some defect problems in 1D hexagonal and ...
Indian Academy of Sciences (India)
We study some typical defect problems in one-dimensional (1D) hexagonal and two-dimensional (2D) octagonal quasicrystals. The first part of this investigation addresses in detail a uniformly moving screw dislocation in a 1D hexagonal piezoelectric quasicrystal with point group 6. A general solution is derived in terms ...
Data of evolutionary structure change: 1B99C-2AZ1D [Confc[Archive
Lifescience Database Archive (English)
Full Text Available GSDS--VESAN >E --HHHHH> ATOM 316...>D 2AZ1D HGSDHEDEGANE >E HHH...pdbID>1B99 C 1B99C EELLT-EVKPN ...> - > ATOM 3319 CA GLU C 141 17.330 5.755...DChain>2AZ1D DELVDWDRDAS re>GG EEGGHcture
Data of evolutionary structure change: 1D07A-2PSEA [Confc[Archive
Lifescience Database Archive (English)
Full Text Available 1D07A-2PSEA 1D07 2PSE A A ---------GA----KPFGEKKFIEIKGRRMAYIDEGTG--DPILFQHGNPTSSYL...MPI-EWADFPEQDRDLFQAFRSQAGEELVLQDNVFVEQVLPGLILRPLSEAEMAAYREPFLAAGEARRPTLSWPRQIPIAGT-PADVVAIARDYAGWLSE...2PSE A 2PSEA DSEKHAENAVIF...2PSE A 2PSEA PLVKGGKPDVV ...2PSE A 2PSEA LRASDDLPKLF
Sodium-dependent transport of [3H](1D)chiro-inositol by Tetrahymena.
Kersting, Michael C; Ryals, Phillip E
2004-01-01
The transport characteristics of (1D)chiro-inositol by the ciliate Tetrahymena were examined in competition studies employing [3H](1D)chiro-inositol. (1D)chiro-Inositol transport was competed by unlabeled (1D)chiro-inositol, myo-inositol, scyllo-inositol, and D-glucose in a concentration-dependent manner. Conversely, (1D)chiro-inositol competed for [3H]myo- and [3H]scyllo-inositol transport. Lineweaver-Burke analysis of the competition data indicated a Km of 10.3 mM and a Bmax of 4.7 nmol/min/mg for (1D)chiro-inositol. Transport of (1D)chiro-inositol was inhibited by cytochalasin B, an inhibitor of facilitated glucose transporters, and phlorizin, an inhibitor of sodium-dependent transporters. Removal of sodium from the radiolabeling buffer also inhibited uptake. The presence of 0.64 mM calcium or magnesium ions exerted negligible effects on transport, although potassium was inhibitory. [3H](1D)chiro-Inositol was shown to be incorporated into Tetrahymena phosphoinositides.
Data of evolutionary structure change: 1D6VH-3GJFK [Confc[Archive
Lifescience Database Archive (English)
Full Text Available 1D6VH-3GJFK 1D6V 3GJF H K QVQLQQSGAELMKPGASVKISCKATGYTFSSY-WIEWVK...ntryChain> 3GJF K 3GJFK DVGGYNYVS...tryChain> 3GJF K 3GJFK QWKSHRSYSC...indel> 2 3GJF K 3GJFK...dex>3 3GJF K 3GJFK
A rational route to SCM materials based on a 1-D cobalt selenocyanato coordination polymer.
Boeckmann, Jan; Näther, Christian
2011-07-07
Thermal annealing of a discrete complex with terminal SeCN anions and monodentate coligands enforces the formation of a 1D cobalt selenocyanato coordination polymer that shows slow relaxation of the magnetization. Therefore, this approach offers a rational route to 1D materials that might show single chain magnetic behaviour. This journal is © The Royal Society of Chemistry 2011
dTBC1D7 regulates systemic growth independently of TSC through insulin signaling.
Ren, Suxia; Huang, Zengyi; Jiang, Yuqiang; Wang, Tao
2017-11-29
The insulin signaling pathway plays key roles in systemic growth. TBC1D7 has recently been identified as the third subunit of the tuberous sclerosis complex (TSC), a negative regulator of cell growth. Here, we used Drosophila as a model system to dissect the physiological function of TBC1D7 in vivo. In mutants lacking TBC1D7, cell and organ growth were promoted, and TBC1D7 limited cell growth in a cell-nonautonomous and TSC-independent manner. TBC1D7 is specifically expressed in insulin-producing cells in the fly brain and regulated biosynthesis and release of insulin-like peptide 2, leading to systemic growth. Furthermore, animals carrying the dTBC1D7 mutation were hypoglycemic, short-lived, and sensitive to oxidative stress. Our findings provide new insights into the physiological function of TBC1D7 in the systemic control of growth, as well as insights into human disorders caused by TBC1D7 mutation. © 2018 Ren et al.
Three-dimensional microstructural effects on plane strain ductile crack growth
DEFF Research Database (Denmark)
Tvergaard, Viggo; Needleman, Alan
2006-01-01
Ductile crack growth under mode 1, plane strain, small scale yielding conditions is analyzed. Overall plane strain loading is prescribed, but a full 3D analysis is carried out to model three dimensional microstructural effects. An elastic-viscoplastic constitutive relation for a porous plastic...... solid is used to model the material. Two populations of secondphase particles are represented, large inclusions with low strength, which result in large voids near the crack tip at an early stage, and small second-phase particles, which require large strains before cavities nucleate. The larger...... inclusions are represented discretely and the effects of different three dimensional distributions on the crack path and on the overall crack growth rate are analyzed. For comparison purposes, a two dimensional distribution of cylindrical inclusions is analyzed. Crack growth occurs off the initial crack...
Digital image plane holography (DIPH) for two-phase flow diagnostics in multiple planes
Palero, V.; Lobera, J.; Arroyo, M. P.
2005-08-01
A technique for measuring the size and displacement of the disperse phase in two planes of a two-phase flow is presented. Digital image plane holography (DIPH) is used for the simultaneous recording and independent reconstruction of both planes. Each fluid plane is illuminated with two laser sheets propagating in opposite directions. The defocused image fields are holographically recorded at 90°, and can be reconstructed either in a defocused or in the best-focused plane. The analysis of the images in a defocused plane provides the sizes, while the cross-correlation of the focused images provides the velocity field, as in a regular particle image velocimetry (PIV) experiment. For air bubbles freely drifting in glycerine, diameters from 50 μm to 400 μm and displacements of up to 300 μm have been measured.
Directory of Open Access Journals (Sweden)
Sujan Chowdhury
2011-01-01
Full Text Available Novel one-dimensional (1D ceria nanostructure has been investigated as a promising and practical approach for the reforming of methanol reaction. Size and shape of the ceria nanomaterials are directly involved with the catalytic activities. Several general synthesis routes as including soft and hard template-assemble phenomenon for the preparation of 1D cerium oxide are discussed. This preparation phenomenon is consisting with low cost and ecofriendly. Nanometer-sized 1D structure provides a high-surface area that can interact with methanol and carbon-monoxide reaction. Overall, nanometer-sized structure provides desirable properties, such as easy recovery and regeneration. As a result, the use of 1D cerium has been suitable for catalytic application of reforming. In this paper, we describe the 1D cerium oxide syntheses route and then summarize their properties in the field of CO oxidation and steam reforming of methanol approach.
Indentation metrology of clamped, ultra-thin elastic sheets.
Vella, Dominic; Davidovitch, Benny
2017-03-15
We study the indentation of ultrathin elastic sheets clamped to the edge of a circular hole. This classical setup has received considerable attention lately, being used by various experimental groups as a probe to measure the surface properties and stretching modulus of thin solid films. Despite the apparent simplicity of this method, the geometric nonlinearity inherent in the mechanical response of thin solid objects renders the analysis of the resulting data a nontrivial task. Importantly, the essence of this difficulty is in the geometric coupling between in-plane stress and out-of-plane deformations, and hence is present in the behaviour of Hookean solids even when the slope of the deformed membrane remains small. Here we take a systematic approach to address this problem, using the membrane limit of the Föppl-von-Kármán equations. This approach highlights some of the dangers in the use of approximate formulae in the metrology of solid films, which can introduce large errors; we suggest how such errors may be avoided in performing experiments and analyzing the resulting data.
Cd1d is expressed on dermal dendritic cells and monocyte-derived dendritic cells.
Gerlini, G; Hefti, H P; Kleinhans, M; Nickoloff, B J; Burg, G; Nestle, F O
2001-09-01
CD1 proteins are a family of cell surface molecules that present lipid antigens to T cells. We investigated skin dendritic cells and monocyte-derived dendritic cells for expression of CD1 molecules using a panel of 10 different monoclonal antibodies focusing on the recently described CD1d molecule. By immunohistochemical analysis, CD1d expression in normal human skin was restricted to dendritic appearing cells in the papillary dermis mainly located in a perivascular localization. Langerhans cells did not show detectable CD1d expression in situ. Epidermal/dermal cell suspensions analyzed by flow cytometry demonstrated distinct subpopulations of HLA-DR positive dermal dendritic cells expressing CD1a, CD1b, and CD1c. CD1d was expressed on HLA-DRbright dermal antigen-presenting cells in dermal suspensions (16% +/- 3.6%), as well as on highly enriched dermal dendritic cells migrating out of skin explants (60.5% +/- 8.0%). Migrated mature dermal dendritic cells coexpressed CD83 and CD1d. Western blot analysis on microdissected skin sections revealed the presence of a 50-55 kDa CD1d molecule in dermis, suggesting that CD1d is highly glycosylated in skin. Both immature and mature monocyte-derived dendritic cells cultured in autologous plasma expressed CD1d molecules. In contrast, culture in fetal bovine serum downregulated CD1d expression. In conclusion, antigen-presenting cells in skin express different sets of CD1 molecules including CD1d and might play a role in lipid antigen presentation in various skin diseases. Differential expression of CD1 molecules depending on culture conditions might have an impact on clinical applications of dendritic cells for immunotherapy.
Wave Propagation in Elastic Solids
1992-06-01
2VN VNi +A2 V n +Vn H )+A I_--U A2 N j1 N, 2 k2 12 1- UN1,j+4I) At 2(1 3 u)( (116) 2L kT3 37 2. Application of the Stress Free Boundary Condition for...ij) is a2 1 - - _~ + DXDfl (139) p277 Thus -x---y at that node in Figure 12 is represented by 1 [ 2vn ’, + vn"~ v+ 0v -v7 _v,~~ n] 2h2 [ ij +l 1 + - v,j...l) + d(2)*rlv2(2:jl-1)... +d(3)*(rlvl(3:jl) + rlvl(l~jl-2)) ... +d(4)*(rlu2Cl:jl-2) - rlu2(3:jl)) ... - td (5)*(rlul(3:jl)- rlul(1:-jl )) ; yr = d(l
New empirical generalizations on the determinants of price elasticity
Bijmolt, THA; Van Heerde, HJ; Pieters, RGM
The importance of pricing decisions for firms has fueled an extensive stream of research on price elasticities. In an influential meta-analytical study, Tellis (1988) summarized price elasticity research findings until 1986. However, empirical generalizations on price elasticity require
GLAMER - II. Multiple-plane gravitational lensing
Petkova, Margarita; Metcalf, R. Benton; Giocoli, Carlo
2014-12-01
We present an extension to multiple planes of the gravitational lensing code GLAMER. The method entails projecting the mass in the observed light-cone on to a discrete number of lens planes and inverse ray-shooting from the image to the source plane. The mass on each plane can be represented as haloes, simulation particles, a projected mass map extracted form a numerical simulation or any combination of these. The image finding is done in a source-oriented fashion, where only regions of interest are iteratively refined on an initially coarse image plane grid. The calculations are performed in parallel on shared memory machines. The code is able to handle different types of analytic haloes (NFW, NSIE, power law, etc.), haloes extracted from numerical simulations and clusters constructed from semi-analytic models (MOKA). Likewise, there are several different options for modelling the source(s) which can be distributed throughout the light-cone. The distribution of matter in the light-cone can be either taken from a pre-existing N-body numerical simulations, from halo catalogues, or are generated from an analytic mass function. We present several tests of the code and demonstrate some of its applications such as generating mock images of galaxy and galaxy cluster lenses.
The horizontal plane appearances of scoliosis
DEFF Research Database (Denmark)
Illés, Tamás S.; Burkus, Máté; Somoskeőy, Szabolcs
2017-01-01
Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two-/three-dimen......Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two...... cases of a normal spine and a thoracic scoliosis are presented. Results: For a normal spine, vector projections in the transverse plane are aligned with the posterior-anterior anatomical axis. For a scoliotic spine, vector projections in the horizontal plane provide information on the lateral...... of scoliosis. The approach used is simple. These results are sufficient for a first visual analysis furnishing significant clinical information in all three anatomical planes. This visualization represents a reasonable compromise between mathematical purity and practical use....
CSIR Research Space (South Africa)
Bogaers, Alfred EJ
2012-07-01
Full Text Available In this paper we outline the development of a 1D finite volume model to solve for blood flow through the arterial system. The model is based on a staggered spatial discretization which leads to a stable solution scheme. This scheme can accurately...
Use of optimized 1D TOCSY NMR for improved quantitation and metabolomic analysis of biofluids
Energy Technology Data Exchange (ETDEWEB)
Sandusky, Peter [Eckerd College, Department of Chemistry (United States); Appiah-Amponsah, Emmanuel; Raftery, Daniel, E-mail: raftery@purdue.edu [Purdue University, Department of Chemistry (United States)
2011-04-15
One dimensional selective TOCSY experiments have been shown to be advantageous in providing improved data inputs for principle component analysis (PCA) (Sandusky and Raftery 2005a, b). Better subpopulation cluster resolution in the observed scores plots results from the ability to isolate metabolite signals of interest via the TOCSY based filtering approach. This report reexamines the quantitative aspects of this approach, first by optimizing the 1D TOCSY experiment as it relates to the measurement of biofluid constituent concentrations, and second by comparing the integration of 1D TOCSY read peaks to the bucket integration of 1D proton NMR spectra in terms of precision and accuracy. This comparison indicates that, because of the extensive peak overlap that occurs in the 1D proton NMR spectra of biofluid samples, bucket integrals are often far less accurate as measures of individual constituent concentrations than 1D TOCSY read peaks. Even spectral fitting approaches have proven difficult in the analysis of significantly overlapped spectral regions. Measurements of endogenous taurine made over a sample population of human urine demonstrates that, due to background signals from other constituents, bucket integrals of 1D proton spectra routinely overestimate the taurine concentrations and distort its variation over the sample population. As a result, PCA calculations performed using data matrices incorporating 1D TOCSY determined taurine concentrations produce better scores plot subpopulation cluster resolution.
Usuki, Tsuneo
2013-09-01
The moduli of conventional elastic structural materials are extended to one of the viscoelastic materials through a modification whereby the dynamic moduli converge to the static moduli of elasticity as the fractional order approaches zero. By plotting phase velocity curves and group velocity curves of plane waves and Rayleigh surface wave for a viscoelastic material (polyvinyl chloride foam), the influence of the fractional order of viscoelasticity is examined. The phase and group velocity curves in the high frequency range were derived for longitudinal, transverse, and Rayleigh waves inherent to the viscoelastic material. In addition, the equation for the phase velocity was mathematically derived on the complex plane, too, and graphically illustrated. A phenomenon was found that, at the moment when the fractional order of the time derivative reaches an integer value 1, the curve on the complex plane becomes completely different, exhibiting snap-through behavior. We examined the mechanism of the snap-through mathematically. Numerical calculation examples were solved, and good agreement was confirmed between the numerical calculation and the analytical expression mentioned above. From the results of the numerical example, regularities were derived for the absolute value of the complex phase and group velocities on the complex plane.
Rosario, Daniel E; Brigham, John C; Aquino, Wilkins
2008-11-01
A numerical study is presented to show the potential for using vibroacoustic-based experiments to identify elastic material properties of orthotropic cylindrical vessels immersed in fluids. Sensitivity analyses and a simulated inverse problem are shown to quantify the potential for material characterization through the use of acoustic emissions. For comparison purposes, the analyses are also shown with the normal component of the velocity at the surface of the cylinder as the measured response in place of the acoustic pressure. The simulated experiment consisted of an orthotropic cylinder immersed in water with an impact force applied to the surface of the cylinder. The material parameters of the cylinder considered in the analyses were the circumferential and longitudinal elastic moduli, and the in-plane shear modulus. The velocity response is shown to provide sufficient information for characterizing all three moduli from a single experiment. Alternatively, the acoustic pressure response is shown to provide sufficient information for characterizing only the two elastic moduli from a single experiment. The analyses show that the acoustic pressure response does not have sufficient sensitivity to the in-plane shear modulus for characterization purposes.
Estimation of In vivo Cancellous Bone Elasticity
Otani, Takahiko; Mano, Isao; Tsujimoto, Toshiyuki; Yamamoto, Tadahito; Teshima, Ryota; Naka, Hiroshi
2009-07-01
The effect of decreasing bone density (a symptom of osteoporosis) is greater for cancellous bone than for dense cortical bone, because cancellous bone is metabolically more active. Therefore, the bone density or bone mineral density of cancellous bone is generally used to estimate the onset of osteoporosis. Elasticity or elastic constant is a fundamental mechanical parameter and is directly related to the mechanical strength of bone. Accordingly, elasticity is a preferable parameter for assessing fracture risk. A novel ultrasonic bone densitometer LD-100 has been developed to determine the mass density and elasticity of cancellous bone with a spatial resolution comparable to that of peripheral quantitative computed tomography. Bone density and bone elasticity are evaluated using ultrasonic parameters based on fast and slow waves in cancellous bone by modeling the ultrasonic wave propagation path. Elasticity is deduced from the measured bone density and the propagation speed of the fast wave. Thus, the elasticity of cancellous bone is approximately expressed by a cubic equation of bone density.
Application of numerical methods to elasticity imaging.
Castaneda, Benjamin; Ormachea, Juvenal; Rodríguez, Paul; Parker, Kevin J
2013-03-01
Elasticity imaging can be understood as the intersection of the study of biomechanical properties, imaging sciences, and physics. It was mainly motivated by the fact that pathological tissue presents an increased stiffness when compared to surrounding normal tissue. In the last two decades, research on elasticity imaging has been an international and interdisciplinary pursuit aiming to map the viscoelastic properties of tissue in order to provide clinically useful information. As a result, several modalities of elasticity imaging, mostly based on ultrasound but also on magnetic resonance imaging and optical coherence tomography, have been proposed and applied to a number of clinical applications: cancer diagnosis (prostate, breast, liver), hepatic cirrhosis, renal disease, thyroiditis, arterial plaque evaluation, wall stiffness in arteries, evaluation of thrombosis in veins, and many others. In this context, numerical methods are applied to solve forward and inverse problems implicit in the algorithms in order to estimate viscoelastic linear and nonlinear parameters, especially for quantitative elasticity imaging modalities. In this work, an introduction to elasticity imaging modalities is presented. The working principle of qualitative modalities (sonoelasticity, strain elastography, acoustic radiation force impulse) and quantitative modalities (Crawling Waves Sonoelastography, Spatially Modulated Ultrasound Radiation Force (SMURF), Supersonic Imaging) will be explained. Subsequently, the areas in which numerical methods can be applied to elasticity imaging are highlighted and discussed. Finally, we present a detailed example of applying total variation and AM-FM techniques to the estimation of elasticity.
National Research Council Canada - National Science Library
Renaud, G; Rivière, J; Le Bas, P.‐Y; Johnson, P.A
2013-01-01
... ). The approach, termed dynamic acousto‐elasticity, is the dynamic analog of static acousto‐elasticity where the wave speed is measured as a function of the applied static load. Dynamic acousto‐elasticity uses low...
1D to 3D diffusion-reaction kinetics of defects in crystals
DEFF Research Database (Denmark)
Trinkaus, H.; Heinisch, H.L.; Barashev, A.V.
2002-01-01
Microstructural features evolving in crystalline solids from diffusion-reaction kinetics of mobile components depend crucially on the dimension of the underlying diffusion process which is commonly assumed to be three-dimensional (3D). In metals, irradiation-induced displacement cascades produce...... clusters of self-interstitials performing 1D diffusion. Changes between equivalent 1D diffusion paths and transversal diffusion result in diffusion-reaction kinetics between one and three dimensions. An analytical approach suggests a single-variable function (master curve) interpolating between the 1D...... and 3D limiting cases. The analytical result is fully confirmed by kinetic Monte Carlo simulations....
SIMULATION OFTHERMO-ELASTICS PROPERTIESOFTHERMALBARRIERCOATINGS
Directory of Open Access Journals (Sweden)
A.M.Ferouani M. Ferouani
2015-07-01
Full Text Available Thermal barrier coatings are used to protect different parts in compressors and turbines from heat. They are generally composed of two layers, one metallic layer providing resistance to heat corrosion and oxidation, and one thermally insulating ceramic layer. Two different techniques are industrially used. Plasma spray results in a lamellar structure granting a low thermal conductivity, but with a low thermal expansion compliance. Electron Beam Physical Vapour Deposition generates a columnar structure allowing a better accommodation of the thermal expansion stresses, entailing improved lifetime of the coating, but with a higher thermal conductivity. The aim of the paper presented here is to develop a procedure of analysis based on the micro structural observation for the prediction of the properties of new coatings in court of industrial development and to predict the effect of the posterior thermal treatment on the properties of the coatings carried out. For a given coating, one has to calculate linear elasticity and its evolution with the temperature as well as thermal expansion, aiming at predicting different parameters related to the in service deterioration.
Elastic/Inelastic Measurement Project
Energy Technology Data Exchange (ETDEWEB)
Yates, Steven [Univ. of Kentucky, Lexington, KY (United States); Hicks, Sally [Univ. of Dallas, TX (United States); Vanhoy, Jeffrey [U.S. Naval Academy, Annapolis, MD (United States); McEllistrem, Marcus [Univ. of Kentucky, Lexington, KY (United States)
2016-03-01
The work scope involves the measurement of neutron scattering from natural sodium (^{23}Na) and two isotopes of iron, ^{56}Fe and ^{54}Fe. Angular distributions, i.e., differential cross sections, of the scattered neutrons will be measured for 5 to 10 incident neutron energies per year. The work of the first year concentrates on ^{23}Na, while the enriched iron samples are procured. Differential neutron scattering cross sections provide information to guide nuclear reaction model calculations in the low-energy (few MeV) fast-neutron region. This region lies just above the isolated resonance region, which in general is well studied; however, model calculations are difficult in this region because overlapping resonance structure is evident and direct nuclear reactions are becoming important. The standard optical model treatment exhibits good predictive ability for the wide-region average cross sections but cannot treat the overlapping resonance features. In addition, models that do predict the direct reaction component must be guided by measurements to describe correctly the strength of the direct component, e.g., β_{2} must be known to describe the direct component of the scattering to the first excited state. Measurements of the elastic scattering differential cross sections guide the optical model calculations, while inelastic differential cross sections provide the crucial information for correctly describing the direct component. Activities occurring during the performance period are described.
Capillary stretching of elastic fibers
Protiere, Suzie; Stone, Howard A.; Duprat, Camille
2014-11-01
Fibrous media consisting of constrained flexible fibers can be found in many engineered systems (membranes in filters, woven textile, matted paper). When such materials interact with a liquid, the presence of liquid/air interfaces induces capillary forces that deform the fibers. To model this interaction we study the behaviour of a finite volume of liquid deposited on two parallel flexible fibers clamped at both ends. A tension along the fibers is imposed and may be varied. We show that the system undergoes various morphological changes as the interfiber distance, the elasticity and the tension of the fibers are varied. For a certain range of parameters, the liquid spreads along the fibers and pulls them together, leading to the ``zipping'' of the fibers. This capillary adhesion can then be enhanced or reduced by changing the tension within the fibers. We will show that balancing stretching and capillary forces allows the prediction of this transition as well as the conditions for which detachment of the fibers occurs. These results may be used to prevent the clogging of fibrous membranes or to optimize the capture of liquids.
Marangoni elasticity of flowing soap films
Kim, Ildoo; Mandre, Shreyas
2016-01-01
We measure the Marangoni elasticity of a flowing soap film to be 22 dyne/cm irrespective of its width, thickness, flow speed, or the bulk soap concentration. We perform this measurement by generating an oblique shock in the soap film and measuring the shock angle, flow speed and thickness. We postulate that the elasticity is constant because the film surface is crowded with soap molecules. Our method allows non-destructive measurement of flowing soap film elasticity, and the value 22 dyne/cm ...
Elasticity of Substitution and Antidumping Measures
DEFF Research Database (Denmark)
Drud Hansen, Jørgen; Meinen, Philipp; Nielsen, Jørgen Ulff-Møller
therefore also vary inversely with the elasticity of substitution at least for countries which have a strong focus on prices in the determination of their anti-dumping measures. We test this for ten countries from 1990 to 2009 using data on anti-dumping from Chad Bown (2010) and US-data at 8-digit level......Abstract This paper analyzes the role of the elasticity of substitution for anti-dumping decisions across countries. In monopolistic competition models with cost heterogeneous firms across countries, price differences vary inversely with the elasticity of substitution. Anti-dumping duties should...
Elastic stiffness of a Skyrmion crystal.
Nii, Y; Kikkawa, A; Taguchi, Y; Tokura, Y; Iwasa, Y
2014-12-31
We observe the elastic stiffness and ultrasonic absorption of a Skyrmion crystal in the chiral-lattice magnet MnSi. The Skyrmion crystal lattice exhibits a stiffness 3 orders of magnitude smaller than that of the atomic lattice of MnSi, being as soft as the flux line lattice in type-II superconductors. The observed anisotropic elastic responses are consistent with the cylindrical shape of the Skyrmion spin texture. Phenomenological analysis reveals that the spin-orbit coupling is responsible for the emergence of anisotropic elasticity in the Skyrmion lattice.
Marangoni elasticity of flowing soap films
Kim, Ildoo; Mandre, Shreyas
2017-08-01
We measure the Marangoni elasticity of a flowing soap film to be 22 mN/m irrespective of its width, thickness, flow speed, or the bulk soap concentration. We perform this measurement by generating an oblique shock in the soap film and measuring the shock angle, flow speed, and thickness. We postulate that the elasticity is constant because the film surface is crowded with soap molecules. Our method allows nondestructive measurement of flowing soap film elasticity and the value 22 mN/m is likely applicable to other similarly constructed flowing soap films.
Topologically protected elastic waves in one-dimensional phononic crystals of continuous media
Kim, Ingi; Iwamoto, Satoshi; Arakawa, Yasuhiko
2018-01-01
We report the design of silica-based 1D phononic crystals (PnCs) with topologically distinct complete phononic bandgaps (PnBGs) and the observation of a topologically protected state of elastic waves at their interface. By choosing different structural parameters of unit cells, two PnCs can possess a common PnBG with different topological natures. At the interface between the two PnCs, a topological interface mode with a quality factor of ∼5,650 is observed in the PnBG. Spatial confinement of the interface mode is also confirmed by the photoelastic imaging technique. Such topologically protected elastic states are potentially applicable in the construction of novel phononic devices.
Asymmetric Junctions Boost in-Plane Thermal Transport in Pillared Graphene.
Sakhavand, Navid; Shahsavari, Rouzbeh
2017-11-15
Hybrid 3D nanoarchitectures by covalent connection of 1D and 2D nanomaterials are currently in high demands to overcome the intrinsic anisotropy of the parent materials. This letter reports the junction configuration-mediated thermal transport properties of Pillared Graphene (PGN) using reverse nonequilibrium molecular dynamics simulations. The asymmetric junctions can offer ∼20% improved in-plane thermal transport in PGN, unlike the intuition that their wrinkled graphene sheets cause phonon scattering. This asymmetric trait, which entails lower phonon scattering provides a new degree of freedom to boost thermal properties of PGN and potentially other hybrid nanostructures.
Asymmetric deep bite with a canted occlusal plane: a case report.
Pinho, Teresa
2013-05-01
Asymmetry and deep bite malocclusions provide management difficulties for clinicians and the combination invites special concern. The purpose of the present paper is to describe a clinical case presenting with an asymmetric deep bite, a canted occlusal plane, a Class II canine relationship on the right side and a Class III canine relationship on the left side, with deviations of both dental midlines to the right. A lower right premolar impaction contributed to the asymmetry and a left first maxillary molar extraction was required for endodontic reasons. A straight-wire technique was used for eighteen months to achieve second molar mesialisation, as well as dental levelling and alignment. To unravel the mandibular arch, resolve the deep bite and manage the canted the lower occlusal plane, two bite turbos were attached to the palatal surface of the maxillary central incisors. In addition, a sectiona Multiloop Edgewise Arch-Wire (MEAW) was placed on the left side and maintained for nine months. Different lower MEAW activation (lateral left lower extrusion) and tip-back control on the posterior teeth were essential mechanics to increase vertical dimension on the lower left side and allow for Class III dental correction. Short Class II vertical elastics on the right side and Class III elastics on the left side were applied. The asymmetric mechanics allowed the case to be treated to a stable sagittal and vertical occlusal result.
Human CD1d-Restricted Natural Killer T (NKT) Cell Cytotoxicity Against Myeloid Cells
National Research Council Canada - National Science Library
Chen, Xiuxu; Gumperz, Jenny E
2006-01-01
CD1d-restricted natural killer T cells (NKT cells) are a unique subpopulation of T lymphocytes that have been shown to be able to promote potent anti-tumor responses in a number of different murine (mouse...
Sensitivity of groundwater recharge using climatic analogues and HYDRUS-1D
National Research Council Canada - National Science Library
Leterme, B; Mallants, D; Jacques, D
2012-01-01
...; this includes estimation of groundwater recharge for the next millennia. Groundwater recharge was simulated using the Richards based soil water balance model HYDRUS-1D and meteorological time series from analogue stations...
Energy Technology Data Exchange (ETDEWEB)
Kong, Chen; Lange, Jeffrey J.; Samovski, Dmitri [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Su, Xiong [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Liu, Jialiu [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States); Sundaresan, Sinju [Department of Internal Medicine, Center for Human Nutrition Washington University School of Medicine, St. Louis, MO 63110 (United States); Stahl, Philip D., E-mail: pstahl@wustl.edu [Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, MO 63110 (United States)
2013-05-03
Highlights: •Hominoid-specific oncogene TBC1D3 is targeted to plasma membrane by palmitoylation. •TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. •TBC1D3 palmitoylation governs growth factors-induced TBC1D3 degradation. •Post-translational modifications may regulate oncogenic properties of TBC1D3. -- Abstract: Expression of the hominoid-specific oncoprotein TBC1D3 promotes enhanced cell growth and proliferation by increased activation of signal transduction through several growth factors. Recently we documented the role of CUL7 E3 ligase in growth factors-induced ubiquitination and degradation of TBC1D3. Here we expanded our study to discover additional molecular mechanisms that control TBC1D3 protein turnover. We report that TBC1D3 is palmitoylated on two cysteine residues: 318 and 325. The expression of double palmitoylation mutant TBC1D3:C318/325S resulted in protein mislocalization and enhanced growth factors-induced TBC1D3 degradation. Moreover, ubiquitination of TBC1D3 via CUL7 E3 ligase complex was increased by mutating the palmitoylation sites, suggesting that depalmitoylation of TBC1D3 makes the protein more available for ubiquitination and degradation. The results reported here provide novel insights into the molecular mechanisms that govern TBC1D3 protein degradation. Dysregulation of these mechanisms in vivo could potentially result in aberrant TBC1D3 expression and promote oncogenesis.
Can a 2-D MT frequency response always be interpreted as a 1-D response?
Parker, Robert L.
2010-04-01
Weidelt and Kaikkonen showed that in the transverse magnetic (TM) mode of magnetotellurics it is not always possible to match exactly the 2-D response at a single site with a 1-D model, although a good approximation usually seems possible. We give a new elementary example of this failure. We show for the first time that the transverse electric (TE) mode responses can also be impossible to match with a 1-D response, and that the deviations can be very large.
Physical Activity Levels of Adolescents with Type 1 Diabetes Physical Activity in T1D.
de Lima, Valderi Abreu; Mascarenhas, Luis Paulo Gomes; Decimo, Juliana Pereira; de Souza, William Cordeiro; Monteiro, Anna Louise Stellfeld; Lahart, Ian; França, Suzana Nesi; Leite, Neiva
2017-05-01
The aim of this study was to evaluate the level of physical activity and cardiorespiratory fitness in teenagers with type 1 diabetes mellitus (T1D) in comparison with healthy scholar participants. Total of 154 teenagers (T1D = 45 and CON = 109). Height, weight, cardiorespiratory fitness (VO2max), and the level of physical activity by the Bouchard's Physical Activity Record were measured, and glycated hemoglobin (HbA1c) in T1D. The VO2max was lower in the T1D (38.38 ± 7.54) in comparison with the CON (42.44 ± 4.65; p < .05). The VO2max had correlation with the amount of time of moderate-to-vigorous physical activity (r = .63; p = .0001) and an inverse correlation with sedentary activities (r= -0.46; p = .006). In the T1D the levels of HbA1c had an inverse correlation with the amount of time of moderate-to-vigorous physical activity (r= -0.34; p = .041) and correlation with the BMI z-score (r = .43; p = .017). Only 37,8% of the participants in the T1D reached the adequate amount of daily moderate-to-vigorous intensity physical activity, in the CON 81,7% reached the WHO's recommendation. T1D had less cardiorespiratory capacity then healthy controls, the teenagers of T1D with lower BMI z-score and that dedicated a greater time in moderate-to-vigorous intensity physical activity demonstrated a better glycemic control.
An effective introduction to structural crystallography using 1D Gaussian atoms
Smith, Emily; Evans, Gwyndaf; Foadi, James
2017-11-01
The most important quantitative aspects of computational structural crystallography can be introduced in a satisfactory way using 1D truncated and periodic Gaussian functions to represent the atoms in a crystal lattice. This paper describes in detail and demonstrates 1D structural crystallography starting with the definition of such truncated Gaussians. The availability of the computer programme CRONE makes possible the repetition of the examples provided in the paper as well as the creation of new ones.
Protective mucosal immunity mediated by epithelial CD1d and IL-10.
Olszak, Torsten; Neves, Joana F; Dowds, C Marie; Baker, Kristi; Glickman, Jonathan; Davidson, Nicholas O; Lin, Chyuan-Sheng; Jobin, Christian; Brand, Stephan; Sotlar, Karl; Wada, Koichiro; Katayama, Kazufumi; Nakajima, Atsushi; Mizuguchi, Hiroyuki; Kawasaki, Kunito; Nagata, Kazuhiro; Müller, Werner; Snapper, Scott B; Schreiber, Stefan; Kaser, Arthur; Zeissig, Sebastian; Blumberg, Richard S
2014-05-22
The mechanisms by which mucosal homeostasis is maintained are of central importance to inflammatory bowel disease. Critical to these processes is the intestinal epithelial cell (IEC), which regulates immune responses at the interface between the commensal microbiota and the host. CD1d presents self and microbial lipid antigens to natural killer T (NKT) cells, which are involved in the pathogenesis of colitis in animal models and human inflammatory bowel disease. As CD1d crosslinking on model IECs results in the production of the important regulatory cytokine interleukin (IL)-10 (ref. 9), decreased epithelial CD1d expression--as observed in inflammatory bowel disease--may contribute substantially to intestinal inflammation. Here we show in mice that whereas bone-marrow-derived CD1d signals contribute to NKT-cell-mediated intestinal inflammation, engagement of epithelial CD1d elicits protective effects through the activation of STAT3 and STAT3-dependent transcription of IL-10, heat shock protein 110 (HSP110; also known as HSP105), and CD1d itself. All of these epithelial elements are critically involved in controlling CD1d-mediated intestinal inflammation. This is demonstrated by severe NKT-cell-mediated colitis upon IEC-specific deletion of IL-10, CD1d, and its critical regulator microsomal triglyceride transfer protein (MTP), as well as deletion of HSP110 in the radioresistant compartment. Our studies thus uncover a novel pathway of IEC-dependent regulation of mucosal homeostasis and highlight a critical role of IL-10 in the intestinal epithelium, with broad implications for diseases such as inflammatory bowel disease.
Juan, Pierre-Alexandre; Dingreville, Rémi
2017-02-01
Interfacial crack fields and singularities in bimaterial interfaces (i.e., grain boundaries or dissimilar materials interfaces) are considered through a general formulation for two-dimensional (2-D) anisotropic elasticity while accounting for the interfacial structure by means of an interfacial elasticity paradigm. The interfacial elasticity formulation introduces boundary conditions that are effectively equivalent to those for a weakly bounded interface. This formalism considers the 2-D crack-tip elastic fields using complex variable techniques. While the consideration of the interfacial elasticity does not affect the order of the singularity, it modifies the oscillatory effects associated with problems involving interface cracks. Constructive or destructive "interferences" are directly affected by the interface structure and its elastic response. This general formulation provides an insight on the physical significance and the obvious coupling between the interface structure and the associated mechanical fields in the vicinity of the crack tip.
Failure of classical elasticity in auxetic foams
National Research Council Canada - National Science Library
Roh, J. H; Giller, C. B; Mott, P. H; Roland, C. M
2013-01-01
.... We find that for the first two materials, having ν ≥ 0.2, the experimental determinations of Poisson's ratio are in good agreement with values calculated from the shear and tensile moduli using the equations of classical elasticity...
ELASTIC CHARACTERIZATION OF Eucalyptus citriodora WOOD
Directory of Open Access Journals (Sweden)
Adriano Wagner Ballarin
2003-01-01
Full Text Available This paper contributed to the elastic characterization of Eucalyptus citriodora grown inBrazil, considering an orthotropic model and evaluating its most important elastic constants.Considering this as a reference work to establish basic elastic ratios — several important elasticconstants of Brazilian woods were not determined yet - the experimental set-up utilized one tree of 65years old from plantations of “Horto Florestal Navarro de Andrade”, at Rio Claro-SP, Brazil. All theexperimental procedures attended NBR 7190/97 – Brazilian Code for wooden structures –withconventional tension and compression tests. Results showed statistical identity between compressionand tension modulus of elasticity. The relation observed between longitudinal and radial modulus ofelasticity was 10 (EL/ER ≈ 10 and same relation, considering shear modulus (modulus of rigidity was20 (EL/GLR ≈ 20. These results, associated with Poisson’s ratios herein determined, allow theoreticalmodeling of wood mechanical behavior in structures.
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 20; Issue 3. Trigonometric Characterization of Some Plane Curves. B Barua J Das. General Article Volume 20 ... Author Affiliations. B Barua1 J Das1. Indian Society of Nonlinear Analysts (INSA), 248 B, B B Chatterjee Road, Kolkata 700 042, W B, India ...
Copernican Revolution in the Complex Plane
Indian Academy of Sciences (India)
IAS Admin
Starting from a simplified model of the Ptole- maic system in the complex plane, we show that. Copernicus' innovation did not merely consist of choosing a reference frame in which the plan- etary motions were simpler, but in finding the size of the planetary orbits expressed in what we now call astronomical units. In modern ...
End Site Control Plane Subsystem (ESCPS)
Energy Technology Data Exchange (ETDEWEB)
Swany, Douglas Martin [Univ. of Delaware, Newark, DE (United States)
2014-08-12
This project researched extending the control plane for dynamic networks into end sites like campuses and laboratories. Key aspects of consideration were signaling over local area network technologies, application integration and monitoring. We studied design considerations for such environments and developed and demonstrated a useful proof of concept implementation and documented implementation strategies for heterogeneous networks.
Optical interconnections to focal plane arrays
Energy Technology Data Exchange (ETDEWEB)
Rienstra, J.L.; Hinckley, M.K.
2000-11-01
The authors have successfully demonstrated an optical data interconnection from the output of a focal plane array to the downstream data acquisition electronics. The demonstrated approach included a continuous wave laser beam directed at a multiple quantum well reflectance modulator connected to the focal plane array analog output. The output waveform from the optical interconnect was observed on an oscilloscope to be a replica of the input signal. They fed the output of the optical data link to the same data acquisition system used to characterize focal plane array performance. Measurements of the signal to noise ratio at the input and output of the optical interconnection showed that the signal to noise ratio was reduced by a factor of 10 or more. Analysis of the noise and link gain showed that the primary contributors to the additional noise were laser intensity noise and photodetector receiver noise. Subsequent efforts should be able to reduce these noise sources considerably and should result in substantially improved signal to noise performance. They also observed significant photocurrent generation in the reflectance modulator that imposes a current load on the focal plane array output amplifier. This current loading is an issue with the demonstrated approach because it tends to negate the power saving feature of the reflectance modulator interconnection concept.
Plane Smoothers for Multiblock Grids: Computational Aspects
Llorente, Ignacio M.; Diskin, Boris; Melson, N. Duane
1999-01-01
Standard multigrid methods are not well suited for problems with anisotropic discrete operators, which can occur, for example, on grids that are stretched in order to resolve a boundary layer. One of the most efficient approaches to yield robust methods is the combination of standard coarsening with alternating-direction plane relaxation in the three dimensions. However, this approach may be difficult to implement in codes with multiblock structured grids because there may be no natural definition of global lines or planes. This inherent obstacle limits the range of an implicit smoother to only the portion of the computational domain in the current block. This report studies in detail, both numerically and analytically, the behavior of blockwise plane smoothers in order to provide guidance to engineers who use block-structured grids. The results obtained so far show alternating-direction plane smoothers to be very robust, even on multiblock grids. In common computational fluid dynamics multiblock simulations, where the number of subdomains crossed by the line of a strong anisotropy is low (up to four), textbook multigrid convergence rates can be obtained with a small overlap of cells between neighboring blocks.
Techniques to measure complex-plane fields
CSIR Research Space (South Africa)
Dudley, Angela L
2014-09-25
Full Text Available In this work we construct coherent superpositions of Gaussian and vortex modes which can be described to occupy the complex-plane. We demonstrate how these fields can be experimentally constructed in a digital, controllable manner with a spatial...
In plane oscillation of a bifilar pendulum
Hinrichsen, Peter F.
2016-11-01
The line tensions, the horizontal and vertical accelerations as well as the period of large angle oscillations parallel to the plane of a bifilar suspension are presented and have been experimentally investigated using strain gauges and a smart phone. This system has a number of advantages over the simple pendulum for studying large angle oscillations, and for measuring the acceleration due to gravity.
Copernican Revolution in the Complex Plane
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 17; Issue 11. Copernican Revolution in the Complex Plane - An Algebraic Way to Show the "Chief Point" of Copernican Innovation. Giorgio Goldoni. General Article Volume 17 Issue 11 November 2012 pp 1065-1084 ...
Southwest, Frontier planes clip wings in Phoenix
National Research Council Canada - National Science Library
Ben Mutzabaugh
2017-01-01
... reports did not specify which one. Video from ABC 15 of Phoenix showed damage to the wing tip of the Southwest plane. A separate image tweeted by CBS 5 of Phoenix indicated that the wing of the Frontier aircraft also was damaged. The Frontier flight was bound for Denver, and the carrier put passengers on a replacement aircraft. Passengers on Southwest's ...
Laser Dazzling of Focal Plane Array Cameras
Schleijpen, H.M.A.; Dimmeler, A.; Eberle, B; Heuvel, J.C. van den; Mieremet, A.L.; Bekman, H.H.P.T.; Mellier, B.
2007-01-01
Laser countermeasures against infrared focal plane array cameras aim to saturate the full camera image. In this paper we will discuss the results of dazzling experiments performed with MWIR lasers. In the “low energy” pulse regime we observe an increasing saturated area with increasing power. The
Deep-Plane Lipoabdominoplasty in East Asians.
Kim, June-Kyu; Jang, Jun-Young; Hong, Yoon Gi; Sim, Hyung Bo; Sun, Sang Hoon
2016-07-01
The objective of this study was to develop a new surgical technique by combining traditional abdominoplasty with liposuction. This combination of operations permits simpler and more accurate management of various abdominal deformities. In lipoabdominoplasty, the combination of techniques is of paramount concern. Herein, we introduce a new combination of liposuction and abdominoplasty using deep-plane flap sliding to maximize the benefits of both techniques. Deep-plane lipoabdominoplasty was performed in 143 patients between January 2007 and May 2014. We applied extensive liposuction on the entire abdomen followed by a sliding flap through the deep plane after repairing the diastasis recti. The abdominal wound closure was completed with repair of Scarpa's fascia. The average amount of liposuction aspirate was 1,400 mL (700-3,100 mL), and the size of the average excised skin ellipse was 21.78×12.81 cm (from 15×10 to 25×15 cm). There were no major complications such as deep-vein thrombosis or pulmonary embolism. We encountered 22 cases of minor complications: one wound infection, one case of skin necrosis, two cases of undercorrection, nine hypertrophic scars, and nine seromas. These complications were solved by conservative management or simple revision. The use of deep-plane lipoabdominoplasty can correct abdominal deformities more effectively and with fewer complications than traditional abdominoplasty.
Trigonometric Characterization of Some Plane Curves
Indian Academy of Sciences (India)
IAS Admin
In this section, various types of families of algebraic curves are considered. Equations of these curves are written either in Cartesian coordinates (x, y) or in terms of plane polar coordinates (r, θ). In some cases, para- metric equations are also considered. 3.1 Astroid. In Cartesian coordinates, the equation of an astroid (Fig-.
Deep-Plane Lipoabdominoplasty in East Asians
Directory of Open Access Journals (Sweden)
June-Kyu Kim
2016-07-01
Full Text Available BackgroundThe objective of this study was to develop a new surgical technique by combining traditional abdominoplasty with liposuction. This combination of operations permits simpler and more accurate management of various abdominal deformities. In lipoabdominoplasty, the combination of techniques is of paramount concern. Herein, we introduce a new combination of liposuction and abdominoplasty using deep-plane flap sliding to maximize the benefits of both techniques.MethodsDeep-plane lipoabdominoplasty was performed in 143 patients between January 2007 and May 2014. We applied extensive liposuction on the entire abdomen followed by a sliding flap through the deep plane after repairing the diastasis recti. The abdominal wound closure was completed with repair of Scarpa's fascia.ResultsThe average amount of liposuction aspirate was 1,400 mL (700–3,100 mL, and the size of the average excised skin ellipse was 21.78×12.81 cm (from 15×10 to 25×15 cm. There were no major complications such as deep-vein thrombosis or pulmonary embolism. We encountered 22 cases of minor complications: one wound infection, one case of skin necrosis, two cases of undercorrection, nine hypertrophic scars, and nine seromas. These complications were solved by conservative management or simple revision.ConclusionsThe use of deep-plane lipoabdominoplasty can correct abdominal deformities more effectively and with fewer complications than traditional abdominoplasty.
VLBI Ecliptic Plane Survey: VEPS-1
Shu, Fengchun; Petrov, Leonid; Jiang, Wu; Xia, Bo; Jiang, Tianyu; Cui, Yuzhu; Takefuji, Kazuhiro; McCallum, Jamie; Lovell, Jim; Yi, Sang-oh; Hao, Longfei; Yang, Wenjun; Zhang, Hua; Chen, Zhong; Li, Jinling
2017-06-01
We present here the results of the first part of the VLBI Ecliptic Plane Survey (VEPS) program. The goal of the program is to find all compact sources within 7\\buildrel{\\circ}\\over{.} 5 of the ecliptic plane that are suitable as calibrators for anticipated phase referencing observations of spacecraft, and determine their positions with accuracy at the 1.5 nrad level. We run the program in two modes: search and refine. In the search mode, a complete sample of all sources brighter than 50 mJy at 5 GHz listed in the Parkes-MIT-NRAO and Green Bank 6 cm (GB6) catalogs, except those previously detected with VLBI, is observed. In the refining mode, the positions of all ecliptic plane sources, including those found in the search mode, are improved. By 2016 October, thirteen 24 hr sessions that targeted all sources brighter than 100 mJy have been observed and analyzed. Among 3320 observed target sources, 555 objects have been detected. We also conducted a number of follow-up VLBI experiments in the refining mode and improved the positions of 249 ecliptic plane sources.
Energy Technology Data Exchange (ETDEWEB)
Tattersall, Wade [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Chiari, Luca [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Machacek, J. R.; Anderson, Emma; Sullivan, James P. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); White, Ron D. [Centre for Antimatter-Matter Studies, School of Engineering and Physical Sciences, James Cook University, Townsville, 4810 Queensland (Australia); Brunger, M. J. [Centre for Antimatter-Matter Studies, School of Chemical and Physical Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Buckman, Stephen J. [Centre for Antimatter-Matter Studies, Research School of Physics and Engineering, The Australian National University, Canberra, ACT 0200 (Australia); Institute of Mathematical Sciences, University of Malaya, 50603 Kuala Lumpur (Malaysia); Garcia, Gustavo [Instituto de Fısica Fundamental, Consejo Superior de Investigationes Cientıficas (CSIC), Serrano 113-bis, E-28006 Madrid (Spain); Blanco, Francisco [Departamento de Fısica Atomica, Molecular y Nuclear, Universidad Complutense de Madrid, E-28040 Madrid (Spain)
2014-01-28
Utilising a high-resolution, trap-based positron beam, we have measured both elastic and inelastic scattering of positrons from water vapour. The measurements comprise differential elastic, total elastic, and total inelastic (not including positronium formation) absolute cross sections. The energy range investigated is from 1 eV to 60 eV. Comparison with theory is made with both R-Matrix and distorted wave calculations, and with our own application of the Independent Atom Model for positron interactions.
Elasticity modulus of rabbit middle ear ossicles determined by a novel micro-indentation technique.
Soons, Joris A M; Aernouts, Jef; Dirckx, Joris J J
2010-05-01
For the purpose of creating a finite element model of the middle ear, the ossicles can be modelled as rigid bodies or as linear elastic materials. The general elasticity parameters used are usually measured on larger bones like the femur. In order to obtain a highly realistic model, the actual elastic modulus (Young's modulus) of the ossicles themselves is needed. We developed a novel 2-needle indentation method of determining the Young's modulus of small samples based on Sneddon's solution. We introduce the second needle in such a way that small specimens can be clamped between the two needles and a symmetry plane is obtained, so that geometry-dependent sample deformations are avoided. A finite element calculated correction factor is used to compensate for the small thickness of the samples. The system was tested on several materials with known parameters in order to validate the technique, and was then used to determine the elasticity parameters of incus and malleus in rabbit. No significant differences between measurement locations were found, and we found an average Young's modulus of 16+/-3 GPa. Copyright (c) 2009 Elsevier B.V. All rights reserved.
Hierarchical elasticity of bimesogenic liquid crystals with twist-bend nematic phase
Yun, Chang-Jun; Vengatesan, M. R.; Vij, Jagdish K.; Song, Jang-Kun
2015-04-01
In 2001, Dozov predicted that twist-bend nematic phase can be spontaneously formed when K33 2, and this phase has recently been discovered in bimesogens. To verify Dozov's hypothesis, we have measured precisely the temperature dependence of the elastic constants of CB7CB in the entire temperature range of nematic phase and in twist-bend nematic phase close to the transition temperature by combing the Fréedericksz threshold methods for a twist nematic and an in-plane switching cells. Anomalous changes in K22 and K33 are observed across the phase transition. The elasticity estimated via extrapolation of the data in the high temperature region of the nematic phase seems to fully satisfy Dozov's hypothesis although the elasticity data in the vicinity of the phase transition exhibit opposite trends. This can be explained by the general nature of a hierarchical system where the macroscopic elasticity is governed mostly by the distortion of a higher level structure.
Flow of Tunable Elastic Microcapsules through Constrictions
do Nascimento, D?bora F.; Avenda?o, Jorge A.; Mehl, Ana; Moura, Maria J. B.; Carvalho, Marcio S.; Duncanson, Wynter J.
2017-01-01
We design and fabricate elastically tunable monodisperse microcapsules using microfluidics and cross-linkable polydimethylsiloxane (PDMS). The overall stiffness of the microcapsules is governed by both the thickness and cross-link ratio of the polymer shell. Flowing suspensions of microcapsules through constricted spaces leads to transient blockage of fluid flow, thus altering the flow behavior. The ability to tune microcapsule mechanical properties enables the design of elastic microcapsules...
Elastic flow instability in nanotube suspensions.
Lin-Gibson, S; Pathak, J A; Grulke, E A; Wang, H; Hobbie, E K
2004-01-30
We report an elastic instability associated with flow-induced clustering in semidilute non-Brownian colloidal nanotubes. Rheo-optical measurements are compared with simulations of mechanical flocculation in sheared fiber suspensions, and the evolving structure is characterized as a function of confinement and shear stress. The transient rheology is correlated with the evolution of highly elastic vorticity-aligned aggregates, with the underlying instability being somewhat ubiquitous in complex fluids.
Import price elasticities: reconsidering the evidence
Hélène Erkel-Rousse; Daniel Mirza
2002-01-01
Recent economic geography and trade empirical studies based on monopolistic competition suggest high levels of trade price elasticities (between 3 and 11). However, price elasticity estimations in trade equations using unit values as price proxies usually lead to lower values of around unity. We show that those inconclusive results may be due to some misspecification in these equations as well as measurement errors in prices. When suitable instrumental variables are used, within a panel of in...
Fracture imaging with converted elastic waves
Energy Technology Data Exchange (ETDEWEB)
Nihei, K.T.; Nakagawa, S.; Myer, L.R.
2001-05-29
This paper examines the seismic signatures of discrete, finite-length fractures, and outlines an approach for elastic, prestack reverse-time imaging of discrete fractures. The results of this study highlight the importance of incorporating fracture-generated P-S converted waves into the imaging method, and presents an alternate imaging condition that can be used in elastic reverse-time imaging when a direct wave is recorded (e.g., for crosswell and VSP acquisition geometries).
Metabolic syndrome and arterial elasticity in youth.
Gardner, Andrew W; Parker, Donald E; Krishnan, Sowmya; Chalmers, Laura J
2013-03-01
To compare arterial elasticity in children, adolescents, and young adults with and without metabolic syndrome (MetS), and to assess which MetS components, demographic measures, and body composition measures are associated with arterial elasticity. Two-hundred six subjects (107 females and 99 males) between the ages of 10 and 20years were recruited by local newspaper advertisements, university email advertisements, and informational flyers. Subjects were assessed on MetS components, demographic measures, body composition measures, and arterial elasticity via radial tonometry. Forty-five subjects (22%) had MetS, as defined by the International Diabetes Federation, and 161 subjects (78%) did not. The primary novel finding was that group differences were not observed for large artery elasticity index (LAEI) (MetS=16.1±4.4 (ml×mmHg(-1))×10 (mean±SD), control=15.4±4.9, (ml×mmHg(-1))×10, p=0.349), and small artery elasticity index (SAEI) (MetS=9.2±2.7 (ml×mmHg(-1))×100, control=8.4±2.9, (ml×mmHg(-1))×100, p=0.063). In the MetS group, fat free mass was positively associated with arterial elasticity, and was the strongest multivariate predictor of LAEI (partial R(2)=0.41) and SAEI (partial R(2)=0.29). Youth with MetS did not exhibit differences in LAEI and SAEI compared to controls. Furthermore, fat free mass of youth with MetS was positively associated with arterial elasticity, and was the strongest predictor of both LAEI and SAEI. The clinical implication is that exercise intervention designed to increase fat free mass might increase arterial elasticity in youth, particularly in youth with MetS. Copyright © 2013 Elsevier Inc. All rights reserved.
Kuni, B; Mussler, J; Kalkum, E; Schmitt, H; Wolf, S I
2016-09-01
To evaluate the effects of kinesiotape, non-elastic tape, and soft brace on segmental foot kinematics during drop landing in subjects with chronic ankle instability and healthy subjects. Controlled study with repeated measurements. Three-dimensional motion analysis laboratory. Twenty participants with chronic ankle instability and 20 healthy subjects. The subjects performed drop landings with 17 retroreflective markers on the foot and lower leg in four conditions: barefoot, with kinesiotape, with non-elastic tape and with a soft brace. Ranges of motion of foot segments using a foot measurement method. In participants with chronic ankle instability, midfoot movement in the frontal plane (inclination of the medial arch) was reduced significantly by non-elastic taping, but kinesiotaping and bracing had no effect. In healthy subjects, both non-elastic taping and bracing reduced that movement. In both groups, non-elastic taping and bracing reduced rearfoot excursion in inversion/eversion significantly, which indicates a stabilisation effect. No such effect was found with kinesiotaping. All three methods reduced maximum plantar flexion significantly. Non-elastic taping stabilised the midfoot best in patients with chronic ankle instability, while kinesiotaping did not influence foot kinematics other than to stabilise the rearfoot in the sagittal plane. ClinicalTrials.gov NCT01810471. Copyright © 2015 Chartered Society of Physiotherapy. Published by Elsevier Ltd. All rights reserved.
Tailoring of in-plane magnetic anisotropy in polycrystalline cobalt thin films by external stress
Energy Technology Data Exchange (ETDEWEB)
Kumar, Dileep, E-mail: dkumar@csr.res.in [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Singh, Sadhana [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Vishawakarma, Pramod [School of Nanotechnology, RGPV, Bhopal 462036 (India); Dev, Arun Singh; Reddy, V.R. [UGC-DAE Consortium for Scientic Research, Khandwa Road, Indore 452001 (India); Gupta, Ajay [Amity Center for Spintronic Materials, Amity University, Sector 125, Noida 201303 (India)
2016-11-15
Polycrystalline Co films of nominal thickness ~180 Å were deposited on intentionally curved Si substrates. Tensile and compressive stresses of 100 MPa and 150 MPa were induced in the films by relieving the curvature. It has been found that, within the elastic limit, presence of stress leads to an in-plane magnetic anisotropy in the film and its strength increases with increasing stress. Easy axis of magnetization in the films is found to be parallel/ transverse to the compressive /tensile stresses respectively. The origin of magnetic anisotropy in the stressed films is understood in terms of magneto- elastic coupling, where the stress try to align the magnetic moments in order to minimize the magneto-elastic as well as anisotropy energy. Tensile stress is also found to be responsible for the surface smoothening of the films, which is attributed to the movement of the atoms associated with the applied stress. The present work provides a possible way to tailor the magnetic anisotropy and its direction in polycrystalline and amorphous films using external stress. - Highlights: • Tensile and compressive stresses were induced in Co films by removing the bending force from the substrates after film deposition. • Controlled external mechanical stress is found to be responsible for magnetic anisotropies in amorphous and polycrystalline thin films, where crystalline anisotropy is absent. • Tensile stress leads to surface smoothening of the polycrystalline Co films.
Income Elasticity Literature Review | Science Inventory | US ...
Following advice from the SAB Council, when estimating the economic value of reductions in air pollution-related mortality and morbidity risk, EPA accounts for the effect of personal income on the willingness to pay to reduce the risk of adverse health outcomes. These income growth adjustment factors are calculated using a combination of income elasticity estimates and income growth projections, both of which have remained essentially unchanged since 1999. These income elasticity estimates vary according to the severity of illness. EPA recently received advice from the SAB regarding the range of income elasticities to apply as well as the research standards to use when selecting income elasticity estimates. Following this advice, EPA consulted with a contractor to update its income elasticity and income growth projections, and generate new income growth adjustment factors. The SAB would evaluate the income elasticity estimates identified in the EPA-provided literature review, determining the extent to which these estimates are appropriate to use in human health benefits assessments.
Elastic reflection waveform inversion with variable density
Li, Yuanyuan
2017-08-17
Elastic full waveform inversion (FWI) provides a better description of the subsurface than those given by the acoustic assumption. However it suffers from a more serious cycle skipping problem compared with the latter. Reflection waveform inversion (RWI) provides a method to build a good background model, which can serve as an initial model for elastic FWI. Therefore, we introduce the concept of RWI for elastic media, and propose elastic RWI with variable density. We apply Born modeling to generate the synthetic reflection data by using optimized perturbations of P- and S-wave velocities and density. The inversion for the perturbations in P- and S-wave velocities and density is similar to elastic least-squares reverse time migration (LSRTM). An incorrect initial model will lead to some misfits at the far offsets of reflections; thus, can be utilized to update the background velocity. We optimize the perturbation and background models in a nested approach. Numerical tests on the Marmousi model demonstrate that our method is able to build reasonably good background models for elastic FWI with absence of low frequencies, and it can deal with the variable density, which is needed in real cases.
Wang, Ji; Yang, Jiashi; Li, Jiangyu
2007-03-01
Energy trapping has important applications in the design of thickness-shear resonators. Considerable efforts have been made for the effective utilization and improvement of energy trapping with variations of plate configurations, such as adding electrodes and contouring. As a new approach in seeking improved energy trapping feature, we analyze thickness-shear vibrations in an elastic plate with functionally graded material (FGM) of in-plane variation of mechanical properties, such as elastic constants and density. A simple and general equation governing the thickness-shear modes is derived from a variational analysis. A plate with piecewise constant material properties is analyzed as an example. It is shown that such a plate can support thickness-shear vibration modes with obvious energy trapping. Bechmann's number for the existence of only one trapped mode also can be determined accordingly.
Sensitivity of Miniaturized Photo-elastic Transducer for Small Force Sensing
Directory of Open Access Journals (Sweden)
Naceur-Eddine KHELIFA
2015-01-01
Full Text Available The sensitivity of a force sensor based on photo-elastic effect in a monolithic Nd- YAG laser depends strongly on the geometrical shape and dimensions of the laser medium. The theoretical predictions of sensitivity are in good agreement with first results obtained with a plano- concave cylindrical crystal of (4´4 mm and some values reported by other groups. However, for small size of the laser sensor, the developed model predicts sensitivity, about 30 % higher than the values given by available experiments. In this paper, we present experimental results obtained with a force sensor using a miniaturized monolithic cylindrical Nd-YAG laser of dimensions (2´3 mm with suitable optical coatings on its plane end faces. The new result of measurement concerning the sensitivity has allowed us to refine the theoretical model to treat photo-elastic force sensors with small dimensions.
Buckling of a stiff thin film on an elastic graded compliant substrate.
Chen, Zhou; Chen, Weiqiu; Song, Jizhou
2017-12-01
The buckling of a stiff film on a compliant substrate has attracted much attention due to its wide applications such as thin-film metrology, surface patterning and stretchable electronics. An analytical model is established for the buckling of a stiff thin film on a semi-infinite elastic graded compliant substrate subjected to in-plane compression. The critical compressive strain and buckling wavelength for the sinusoidal mode are obtained analytically for the case with the substrate modulus decaying exponentially. The rigorous finite element analysis (FEA) is performed to validate the analytical model and investigate the postbuckling behaviour of the system. The critical buckling strain for the period-doubling mode is obtained numerically. The influences of various material parameters on the results are investigated. These results are helpful to provide physical insights on the buckling of elastic graded substrate-supported thin film.
Structural, electronic and elastic properties of REIr2 (RE=La and Ce) Laves phase compounds
Shrivastava, Deepika; Fatima, Bushra; Sanyal, Sankar P.
2016-05-01
REIr2 (RE = La and Ce) Laves phase intermetallic compounds were investigated with respect to their structural, electronic and elastic properties using full potential linearized augmented plane wave (FP-LAPW) method within generalized gradient approximation (GGA) as implemented in WIEN2k code. The ground state properties such as lattice constants (a0), bulk modulus (B), pressure derivative of bulk modulus (Bꞌ) and density of state at Fermi level N(EF) have been obtained by optimization method. The electronic structure (BS, TDOS and PDOS) reveals that these Laves phase compounds are metallic in nature. The calculated elastic constants indicate that these compounds are mechanically stable at ambient pressure and found to be ductile in nature.
Parametric Stability of Non-Linearly Elastic Composite Plates by Lyapunov Exponents
GILAT, R.; ABOUDI, J.
2000-08-01
The dynamic stability of non-linearly elastic composite plates subjected to periodic in-plane loading is investigated. Infinitely wide plates made of resin matrix composite are considered. The non-linearly elastic behavior of the resin matrix is modelled by the generalized Ramberg-Osgood representation. The effect of the matrix non-linearity on the overall response of the composite is predicted by the micromechanical method of cells. The dynamic stability analysis is performed by evaluating the largest Lyapunov exponent, the sign of which indicates whether the system is stable or not. It is shown that this approach forms a convenient tool for predicting parametric stability of non-linear composite structures.
Acharya, Nikita; Fatima, Bushra; Chouhan, Sunil Singh; Sanyal, Sankar P.
2013-06-01
We have investigated the structural, electronic, elastic and thermal properties of CoTi and CoZr using ab-initio full potential linearized plane wave method (FP-LAPW) method within generalized gradient approximation (GGA). The calculated the ground state and electronic properties such as lattice constant (a0), bulk modulus (B0), its pressure derivative (B0') and density of states at Fermi level N (EF) which are in good agreement with other experimental and theoretical results. The elastic constants (C11, C12 and C44) are also calculated for these compounds. Ductility has been analyzed by Pugh's rule (B/GH) ratio and Cauchy's pressure (C12-C44). To the best of our knowledge, the elastic and thermal properties of CoZr are calculated first time.
Validation of the one-dimensional compositional reservoir simulator (CRSIM-1D): Technical note
Energy Technology Data Exchange (ETDEWEB)
Klara, S.M.; Holifield, T.F.
1987-11-01
The analysis presented in this manuscript validates the one-dimensional compositional reservoir simulator (CRSIM-1D). CRSIM-1D was developed at the Morgantown Energy Technology Center (METC), and is the first stage of an ongoing investigation of methods for increasing sweep efficiency of miscible EOR carbon dioxide (CO/sub 2/) floods. After its development, the simulator was validated to (1) ensure reliable predictions, (2) understand the sensitivity of input parameters, and (3) identify stability limitations of the code. The results from this study are presented in this report. The first part of this report summarized the results from the comparison of predictions from CRSIM-1D with both experimental data and the predictions from simulators. Four problems from the literature were examined: (1) 3-component oil displaced by a rich gas using single-point upstream weighting, (2) 3-component oil displaced by a rich gas using two-point upstream weighting, (3) 3-component oil displaced by a lean gas, and (4) 15-component oil displaced by CO/sub 2/. In all cases, the results from CRSIM-1D compare well with the results from the literature. Additionally, this report discusses the sensitivity of CRSIM-1D with regard to computational and physical variables. Sensitivities were evaluated for a wide range of physical variables (injection rate, porosity, etc.) and computational variables (time step size and grid size). Part of this evaluation compares CRSIM-1D's predictions to exact solutions that exist for simple problems such as incompressible immiscible floods. These comparisons should provide potential users with insight into the accuracy of predictions from CRSIM-1D. 18 refs., 15 tabs.
The autophagy machinery restrains iNKT cell activation through CD1D1 internalization.
Keller, Christian W; Loi, Monica; Ewert, Svenja; Quast, Isaak; Theiler, Romina; Gannagé, Monique; Münz, Christian; De Libero, Gennaro; Freigang, Stefan; Lünemann, Jan D
2017-06-03
Invariant natural killer T (iNKT) cells are innate T cells with powerful immune regulatory functions that recognize glycolipid antigens presented by the CD1D protein. While iNKT cell-activating glycolipids are currently being explored for their efficacy to improve immunotherapy against infectious diseases and cancer, little is known about the mechanisms that control CD1D antigen presentation and iNKT cell activation in vivo. CD1D molecules survey endocytic pathways to bind lipid antigens in MHC class II-containing compartments (MIICs) before recycling to the plasma membrane. Autophagosomes intersect with MIICs and autophagy-related proteins are known to support antigen loading for increased CD4+ T cell immunity. Here, we report that mice with dendritic cell (DC)-specific deletion of the essential autophagy gene Atg5 showed better CD1D1-restricted glycolipid presentation in vivo. These effects led to enhanced iNKT cell cytokine production upon antigen recognition and lower bacterial loads during Sphingomonas paucimobilis infection. Enhanced iNKT cell activation was independent of receptor-mediated glycolipid uptake or costimulatory signals. Instead, loss of Atg5 in DCs impaired clathrin-dependent internalization of CD1D1 molecules via the adaptor protein complex 2 (AP2) and, thus, increased surface expression of stimulatory CD1D1-glycolipid complexes. These findings indicate that the autophagic machinery assists in the recruitment of AP2 to CD1D1 molecules resulting in attenuated iNKT cell activation, in contrast to the supporting role of macroautophagy in CD4+ T cell stimulation.
3D Quasi-Static Ultrasound Elastography With Plane Wave In Vivo.
Papadacci, Clement; Bunting, Ethan A; Konofagou, Elisa E
2017-02-01
In biological tissue, an increase in elasticity is often a marker of abnormalities. Techniques such as quasi-static ultrasound elastography have been developed to assess the strain distribution in soft tissues in two dimensions using a quasi-static compression. However, as abnormalities can exhibit very heterogeneous shapes, a three dimensional approach would be necessary to accurately measure their volume and remove operator dependency. Acquisition of volumes at high rates is also critical to performing real-time imaging with a simple freehand compression. In this study, we developed for the first time a 3D quasi-static ultrasound elastography method with plane waves that estimates axial strain distribution in vivo in entire volumes at high volume rate. Acquisitions were performed with a 2D matrix array probe of 2.5 MHz frequency and 256 elements. Plane waves were emitted at a volume rate of 100 volumes/s during a continuous motorized and freehand compression. 3D B-mode volumes and 3D cumulative axial strain volumes were successfully estimated in inclusion phantoms and in ex vivo canine liver before and after a high intensity focused ultrasound ablation. We also demonstrated the in vivo feasibility of the method using freehand compression on the calf muscle of a human volunteer and were able to retrieve 3D axial strain volume at a high volume rate depicting the differences in stiffness of the two muscles which compose the calf muscle. 3D ultrasound quasi-static elastography with plane waves could become an important technique for the imaging of the elasticity in human bodies in three dimensions using simple freehand scanning.
Huygens-Fresnel picture for electron-molecule elastic scattering★
Baltenkov, Arkadiy S.; Msezane, Alfred Z.
2017-11-01
The elastic scattering cross sections for a slow electron by C2 and H2 molecules have been calculated within the framework of the non-overlapping atomic potential model. For the amplitudes of the multiple electron scattering by a target the wave function of the molecular continuum is represented as a combination of a plane wave and two spherical waves generated by the centers of atomic spheres. This wave function obeys the Huygens-Fresnel principle according to which the electron wave scattering by a system of two centers is accompanied by generation of two spherical waves; their interaction creates a diffraction pattern far from the target. Each of the Huygens waves, in turn, is a superposition of the partial spherical waves with different orbital angular momenta l and their projections m. The amplitudes of these partial waves are defined by the corresponding phases of electron elastic scattering by an isolated atomic potential. In numerical calculations the s- and p-phase shifts are taken into account. So the number of interfering electron waves is equal to eight: two of which are the s-type waves and the remaining six waves are of the p-type with different m values. The calculation of the scattering amplitudes in closed form (rather than in the form of S-matrix expansion) is reduced to solving a system of eight inhomogeneous algebraic equations. The differential and total cross sections of electron scattering by fixed-in-space molecules and randomly oriented ones have been calculated as well. We conclude by discussing the special features of the S-matrix method for the case of arbitrary non-spherical potentials. Contribution to the Topical Issue "Low energy positron and electron interactions", edited by James Sullivan, Ron White, Michael Bromley, Ilya Fabrikant, and David Cassidy.
Elastic modulus measurements of LDEF glasses and glass-ceramics using a speckle technique
Wiedlocher, D. E.; Kinser, D. L.
1992-01-01
Elastic moduli of five glass types and the glass-ceramic Zerodur, exposed to a near-earth orbit environment on the Long Duration Exposure Facility (LDEF), were compared to that of unexposed samples. A double exposure speckle photography technique utilizing 633 nm laser light was used in the production of the speckle pattern. Subsequent illumination of a double exposed negative using the same wavelength radiation produces Young's fringes from which the in-plane displacements are measured. Stresses imposed by compressive loading produced measurable strains in the glasses and glass-ceramic.
Research on assessment of bolted joint state using elastic wave propagation
Kędra, R.; Rucka, M.
2015-07-01
The work contains results of experimental investigation of elastic wave propagation in a bolted single-lap joint. Tests were carried out for the excitation perpendicular to the connection plane. In experimental studies, PZT transducers were used for both excitation and registration of ultrasonic waves. The analyses took into account varying contact conditions between the elements of the connection depending on the value of the prestressing force. The influence of loosening/tightening of bolts on the energy dissipation was analysed. The experimental results proved the influence of bolt torque on quantitative characteristics of the signals. To improve the diagnostic possibilities only the initial parts of signals were analysed.
Elasticity $\\mathscr{M}$-tensors and the Strong Ellipticity Condition
Ding, Weiyang; Liu, Jinjie; Qi, Liqun; Yan, Hong
2017-01-01
In this paper, we propose a class of tensors satisfying the strong ellipticity condition. The elasticity $\\mathscr{M}$-tensor is defined with respect to the M-eigenvalues of elasticity tensors. We prove that any nonsingular elasticity $\\mathscr{M}$-tensor satisfies the strong ellipticity condition by employing a Perron-Frobenius-type theorem for M-spectral radii of nonnegative elasticity tensors. We also establish other equivalent definitions of nonsingular elasticity $\\mathscr{M}$-tensors.
Is the Armington Elasticity Really Constant across Importers?
Yilmazkuday, Hakan
2009-01-01
This paper shows that the Armington elasticity, which refers to both the elasticity of substitution across goods and the price elasticity of demand under the assumption of a large number of varieties, systematically changes from one importer country to another in an international trade context. Then a natural question to ask is "What determines the Armington elasticity?" The answer comes from the distinction between the elasticity of demand with respect to the destination price (i.e., the Arm...
Noncoherent Spectral Optical CDMA System Using 1D Active Weight Two-Code Keying Codes
Directory of Open Access Journals (Sweden)
Bih-Chyun Yeh
2016-01-01
Full Text Available We propose a new family of one-dimensional (1D active weight two-code keying (TCK in spectral amplitude coding (SAC optical code division multiple access (OCDMA networks. We use encoding and decoding transfer functions to operate the 1D active weight TCK. The proposed structure includes an optical line terminal (OLT and optical network units (ONUs to produce the encoding and decoding codes of the proposed OLT and ONUs, respectively. The proposed ONU uses the modified cross-correlation to remove interferences from other simultaneous users, that is, the multiuser interference (MUI. When the phase-induced intensity noise (PIIN is the most important noise, the modified cross-correlation suppresses the PIIN. In the numerical results, we find that the bit error rate (BER for the proposed system using the 1D active weight TCK codes outperforms that for two other systems using the 1D M-Seq codes and 1D balanced incomplete block design (BIBD codes. The effective source power for the proposed system can achieve −10 dBm, which has less power than that for the other systems.
1D pixelated MV portal imager with structured privacy film: a feasibility study
Baturin, Pavlo; Shedlock, Daniel; Myronakis, Marios; Berbeco, Ross; Star-Lack, Josh
2017-03-01
Modern amorphous silicon flat panel-based electronic portal imaging devices that utilize thin gadolinium oxysulfide scintillators suffer from low quantum efficiencies (QEs). Thick two dimensionally (2D) pixelated scintillator arrays offer an effective but expensive option for increasing QE. To reduce costs, we have investigated the possibility of combining a thick one dimensional (1D) pixelated scintillator (PS) with an orthogonally placed 1D structured optical filter to provide for overall good 2D spatial resolution. In this work, we studied the potential for using a 1D video screen privacy film (PF) to serve as a directional optical attenuator and filter. A Geant4 model of the PF was built based on reflection and transmission measurements taken with a laser-based optical reflectometer. This information was incorporated into a Geant4-based x-ray detector simulator to generate modulation transfer functions (MTFs), noise power spectra (NPS), and detective quantum efficiencies (DQEs) for various 1D and 2D configurations. It was found that the 1D array with PF can provide the MTFs and DQEs of 2D arrays. Although the PF significantly reduced the amount of optical photons detected by the flat panel, we anticipate using a scintillator with an inherently high optical yield (e.g. cesium iodide) for MV imaging, where fluence rates are inherently high, will still provide adequate signal intensities for the imaging tasks associated with radiotherapy.
Starbugs: focal plane fiber positioning technology
Goodwin, Michael; Heijmans, Jeroen; Saunders, Ian; Brzeski, Jurek; Saunders, Will; Muller, Rolf; Haynes, Roger; Gilbert, James
2010-07-01
We report on the technological achievements of our latest Starbug prototypes and their implications for smart focal plane fiber positioning applications for wide-field astronomy. The Starbugs are innovative self-motile miniature robotic devices that can simultaneously and independently position fibers or payloads over a field plate located at the telescope's focal plane. The Starbugs concept overcomes many of the limitations associated with the traditional 'pick and place' positioners where a robot places fixed buttons onto the field plate. The new Starbug prototypes use piezoelectric actuators and have the following features: (i) new 'lift-and-step' method (discrete step) for accurate positioning over different surfaces; and (ii) operate in an inverted hanging position underneath a transparent field plate, removing the need for fibercable retractors. In this paper, we present aspects of the Starbug prototypes, including the theoretical model, mechanical design, experimental setup, algorithms, performance and applications for astronomical instrumentation.
Structure analysis for plane geometry figures
Feng, Tianxiao; Lu, Xiaoqing; Liu, Lu; Li, Keqiang; Tang, Zhi
2013-12-01
As there are increasing numbers of digital documents for education purpose, we realize that there is not a retrieval application for mathematic plane geometry images. In this paper, we propose a method for retrieving plane geometry figures (PGFs), which often appear in geometry books and digital documents. First, detecting algorithms are applied to detect common basic geometry shapes from a PGF image. Based on all basic shapes, we analyze the structural relationships between two basic shapes and combine some of them to a compound shape to build the PGF descriptor. Afterwards, we apply matching function to retrieve candidate PGF images with ranking. The great contribution of the paper is that we propose a structure analysis method to better describe the spatial relationships in such image composed of many overlapped shapes. Experimental results demonstrate that our analysis method and shape descriptor can obtain good retrieval results with relatively high effectiveness and efficiency.
Multi-planed unified switching topologies
Chen, Dong; Heidelberger, Philip; Sugawara, Yutaka
2017-07-04
An apparatus and method for extending the scalability and improving the partitionability of networks that contain all-to-all links for transporting packet traffic from a source endpoint to a destination endpoint with low per-endpoint (per-server) cost and a small number of hops. An all-to-all wiring in the baseline topology is decomposed into smaller all-to-all components in which each smaller all-to-all connection is replaced with star topology by using global switches. Stacking multiple copies of the star topology baseline network creates a multi-planed switching topology for transporting packet traffic. Point-to-point unified stacking method using global switch wiring methods connects multiple planes of a baseline topology by using the global switches to create a large network size with a low number of hops, i.e., low network latency. Grouped unified stacking method increases the scalability (network size) of a stacked topology.
Waveguide metacouplers for in-plane polarimetry
Pors, Anders
2016-01-01
The state of polarization (SOP) is an inherent property of the vectorial nature of light and a crucial parameter in a wide range of remote sensing applications. Nevertheless, the SOP is rather cumbersome to probe experimentally, as conventional detectors only respond to the intensity of the light, hence loosing the phase information between orthogonal vector components. In this work, we propose a new type of polarimeter that is compact and well-suited for in-plane optical circuitry, while allowing for immediate determination of the SOP through simultaneous retrieval of the associated Stokes parameters. The polarimeter is based on plasmonic phase-gradient birefringent metasurfaces that facilitate normal incident light to launch in-plane photonic waveguide modes propagating in six predefined directions with the coupling efficiencies providing a direct measure of the incident SOP. The functionality and accuracy of the polarimeter, which essentially is an all-polarization sensitive waveguide metacoupler, is confi...
Teal Amber Visible Focal Plane Technology
Johnson, Charles R.; Burczewski, Ron
1981-12-01
Deep-space surveillance missions have imposed severe demands on existing technology and simulated the search for new, advanced technology developments to provide higher performance. Defense Advanced Research Projects Agency (DARPA) sponsored Teal Amber as a visible charge-coupled device (CCD) and associated focal plane signal processing technology development and demonstration program. This paper describes this large-scale, staring-array-sensor concept. The current state of art in the resulting visibled CCD imagers is specified, along with the focal plane signal processor implementation in low power-weight-volume large-scale integrated (LSI) circuitry. Performance requirements and analytic predictions are compared to demonstration system results from an electro-optical test site in White Sands, New Mexico.
Elastic compliance of single-edge-notched tension SE(T (or SENT specimens
Directory of Open Access Journals (Sweden)
B. Tyson
2014-10-01
Full Text Available There has been a trend recently to use specimen geometries for toughness measurement that are more representative of actual flaw geometries in service. A prominent example is the use of single-edge-notched tension specimens for assessment of surface flaws in pipelines. To obtain a resistance (R curve, i.e. J-integral or CTOD as a function of crack growth, it is necessary to monitor the crack size as a function of J or CTOD. To facilitate obtaining these data from a single specimen, the elastic CMOD unloading compliance C has been used in several testing programs to estimate crack size. C is a function of several variables in addition to crack size – notably, specimen constraint (plane stress or plane strain. In this paper, the dependence of C on these variables will be discussed.
Morphological segmentation for sagittal plane image analysis.
Bezerra, F N; Paula, I C; Medeiros, F S; Ushizima, D M; Cintra, L S
2010-01-01
This paper introduces a morphological image segmentation method by applying watershed transform with markers to scale-space smoothed images and furthermore provides images for clinical monitoring and analysis of patients. The database comprises sagittal plane images taken from a digital camera of patients submitted to Global Postural Reeducation (GPR) physiotherapy treatment. Orthopaedic specialists can use these segmented images to diagnose posture problems, assess physiotherapy treatment evolution and thus reduce diagnostic errors due to subjective analysis.
Wafer plane inspection for advanced reticle defects
Nagpal, Rajesh; Ghadiali, Firoz; Kim, Jun; Huang, Tracy; Pang, Song
2008-05-01
Readiness of new mask defect inspection technology is one of the key enablers for insertion & transition of the next generation technology from development into production. High volume production in mask shops and wafer fabs demands a reticle inspection system with superior sensitivity complemented by a low false defect rate to ensure fast turnaround of reticle repair and defect disposition (W. Chou et al 2007). Wafer Plane Inspection (WPI) is a novel approach to mask defect inspection, complementing the high resolution inspection capabilities of the TeraScanHR defect inspection system. WPI is accomplished by using the high resolution mask images to construct a physical mask model (D. Pettibone et al 1999). This mask model is then used to create the mask image in the wafer aerial plane. A threshold model is applied to enhance the inspectability of printing defects. WPI can eliminate the mask restrictions imposed on OPC solutions by inspection tool limitations in the past. Historically, minimum image restrictions were required to avoid nuisance inspection stops and/or subsequent loss of sensitivity to defects. WPI has the potential to eliminate these limitations by moving the mask defect inspections to the wafer plane. This paper outlines Wafer Plane Inspection technology, and explores the application of this technology to advanced reticle inspection. A total of twelve representative critical layers were inspected using WPI die-to-die mode. The results from scanning these advanced reticles have shown that applying WPI with a pixel size of 90nm (WPI P90) captures all the defects of interest (DOI) with low false defect detection rates. In validating CD predictions, the delta CDs from WPI are compared against Aerial Imaging Measurement System (AIMS), where a good correlation is established between WPI and AIMSTM.
Nueva movilidad : Park & ride Les Planes
Guerrero Riveiro, Fermín Hernán
2016-01-01
El ejercicio nace con un extenso análisis sobre las realidades del Area Metropolitana de Barcelona que pone de manifiesto el déficit de estacionamientos de disuasión o "Parks and Rides" en torno a las estaciones de tren. Posteriormente se explora, a fondo, uno de estos puntos detectados (Les Planes) y se plantean una serie de intervenciones de mejora.
Out-of-plane chiral domain wall spin-structures in ultrathin in-plane magnets
Chen, Gong; Kang, Sang Pyo; Ophus, Colin; N'diaye, Alpha T.; Kwon, Hee Young; Qiu, Ryan T.; Won, Changyeon; Liu, Kai; Wu, Yizheng; Schmid, Andreas K.
2017-05-01
Chiral spin textures in ultrathin films, such as skyrmions or chiral domain walls, are believed to offer large performance advantages in the development of novel spintronics technologies. While in-plane magnetized films have been studied extensively as media for current- and field-driven domain wall dynamics with applications in memory or logic devices, the stabilization of chiral spin textures in in-plane magnetized films has remained rare. Here we report a phase of spin structures in an in-plane magnetized ultrathin film system where out-of-plane spin orientations within domain walls are stable. Moreover, while domain walls in in-plane films are generally expected to be non-chiral, we show that right-handed spin rotations are strongly favoured in this system, due to the presence of the interfacial Dzyaloshinskii-Moriya interaction. These results constitute a platform to explore unconventional spin dynamics and topological phenomena that may enable high-performance in-plane spin-orbitronics devices.
Kamas, Tuncay; Lin, Bin; Giurgiutiu, Victor
2013-04-01
This paper discusses theoretical analysis of electro-mechanical impedance spectroscopy (EMIS) of piezoelectric wafer active sensor (PWAS). Both free and constrained PWAS EMIS models are developed for in-plane (lengthwise) and outof plane (thickness wise) mode. The paper starts with the general piezoelectric constitutive equations that express the linear relation between stress, strain, electric field and electric displacement. This is followed by the PWAS EMIS models with two assumptions: 1) constant electric displacement in thickness direction (D3) for out-of-plane mode; 2) constant electric field in thickness direction (E3) for in-plane mode. The effects of these assumptions on the free PWAS in-plane and out-of-plane EMIS models are studied and compared. The effects of internal damping of PWAS are considered in the analytical EMIS models. The analytical EMIS models are verified by Coupled Field Finite Element Method (CF-FEM) simulations and by experimental measurements. The extent of the agreement between the analytical and experimental EMIS results is discussed. The paper ends with summary, conclusions, and suggestions for future work.
The Off-plane Grating Rocket Experiment
Donovan, Benjamin
2018-01-01
The next generation of X-ray spectrometers necessitate significant increases in both resolution and effective area to achieve the science goals set forth in the 2010 Decadal Survey and the 2013 Astrophysics Roadmap. The Off-plane Grating Rocket Experiment (OGRE), an X-ray spectroscopy suborbital rocket payload currently scheduled for launch in Q3 2020, will serve as a testbed for several key technologies which can help achieve the desired performance increases of future spectrometers. OGRE will be the first instrument to fly mono-crystalline silicon X-ray mirrors developed at NASA Goddard Space Flight Center. The payload will also utilize an array of off-plane gratings manufactured at The Pennsylvania State University. Additionally, the focal plane will be populated with an array of four electron-multiplying CCDs developed by the Open University and XCAM Ltd. With these key technologies, OGRE hopes to achieve the highest resolution on-sky soft X-ray spectrum to date. We discuss the optical design, expected performance, and the current status of the payload.
Numerical Flow Analysis of Planing Boats
Brucker, Kyle; O'Shea, Thomas; Dommermuth, Douglas; Fu, Thomas
2012-11-01
The focus of this presentation is to describe the recent effort to validate the computer code Numerical Flow Analysis (NFA) for the prediction of hydrodynamic forces and moments associated with deep-V planing craft. This detailed validation effort was composed of two parts. The first part focuses on assessing NFA's ability to predict pressures on the surface of a 10 degree deadrise wedge during impact with an undisturbed free surface. Detailed comparisons to pressure gauges are presented for two different drop heights, 6 inches and 10 inches. Results show NFA accurately predicted pressures during the slamming event. The second part of the validation study focused on assessing how well NFA was able to accurately model the complex multiphase flow associated with high Froude number flows, specifically the formation of the spray sheet. NFA simulations of a planing hull fixed at various angles of roll (0 degrees, 10 degrees, 20 degrees, and 30 degrees) were compared to experiments from Judge (2012). Comparisons to underwater photographs illustrate NFA's ability to model the formation of the spray sheet and the free surface turbulence associated with planing boat hydrodynamics.
Blackfolds, plane waves and minimal surfaces
Energy Technology Data Exchange (ETDEWEB)
Armas, Jay [Physique Théorique et Mathématique, Université Libre de Bruxelles and International Solvay Institutes, ULB-Campus Plaine CP231, B-1050 Brussels (Belgium); Albert Einstein Center for Fundamental Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland); Blau, Matthias [Albert Einstein Center for Fundamental Physics, University of Bern,Sidlerstrasse 5, 3012 Bern (Switzerland)
2015-07-29
Minimal surfaces in Euclidean space provide examples of possible non-compact horizon geometries and topologies in asymptotically flat space-time. On the other hand, the existence of limiting surfaces in the space-time provides a simple mechanism for making these configurations compact. Limiting surfaces appear naturally in a given space-time by making minimal surfaces rotate but they are also inherent to plane wave or de Sitter space-times in which case minimal surfaces can be static and compact. We use the blackfold approach in order to scan for possible black hole horizon geometries and topologies in asymptotically flat, plane wave and de Sitter space-times. In the process we uncover several new configurations, such as black helicoids and catenoids, some of which have an asymptotically flat counterpart. In particular, we find that the ultraspinning regime of singly-spinning Myers-Perry black holes, described in terms of the simplest minimal surface (the plane), can be obtained as a limit of a black helicoid, suggesting that these two families of black holes are connected. We also show that minimal surfaces embedded in spheres rather than Euclidean space can be used to construct static compact horizons in asymptotically de Sitter space-times.
Numerical modelling of orthogonal cutting: application to woodworking with a bench plane.
Nairn, John A
2016-06-06
A numerical model for orthogonal cutting using the material point method was applied to woodcutting using a bench plane. The cutting process was modelled by accounting for surface energy associated with wood fracture toughness for crack growth parallel to the grain. By using damping to deal with dynamic crack propagation and modelling all contact between wood and the plane, simulations could initiate chip formation and proceed into steady-state chip propagation including chip curling. Once steady-state conditions were achieved, the cutting forces became constant and could be determined as a function of various simulation variables. The modelling details included a cutting tool, the tool's rake and grinding angles, a chip breaker, a base plate and a mouth opening between the base plate and the tool. The wood was modelled as an anisotropic elastic-plastic material. The simulations were verified by comparison to an analytical model and then used to conduct virtual experiments on wood planing. The virtual experiments showed interactions between depth of cut, chip breaker location and mouth opening. Additional simulations investigated the role of tool grinding angle, tool sharpness and friction.
A 4-Mid-Node Plane Model of Base Force Element Method on Complementary Energy Principle
Directory of Open Access Journals (Sweden)
Yinghua Liu
2013-01-01
Full Text Available Using the base forces as fundamental variables to describe the stress state and the displacement gradients that are the conjugate variables of the base forces to describe the deformation state for the two-dimensional elasticity problems, a 4-mid-node plane model of base force element method (BFEM based on complementary energy principle is proposed. In this paper, the complementary energy of an element of the BFEM is constructed by using the base forces. The equilibrium conditions are released by the Lagrange multiplier method, and a modified complementary energy principle described by the base forces is obtained. The formulation of the 4-mid-node plane element of the BFEM is derived by assuming that the stress is uniformly distributed on each edge of the plane elements. A procedure of the BFEM on complementary energy principle is developed using MATLAB language. The numerical results of examples show that this model of the BFEM has high precision and is free from mesh sensitivity. This model shows good performances.
Precession-torque-driven domain-wall motion in out-of-plane materials
Peeters, M. J. G.; Ummelen, F. C.; Lalieu, M. L. M.; Kim, J.-S.; Swagten, H. J. M.; Koopmans, B.
2017-05-01
Domain-wall (DW) motion in magnetic nanostrips is intensively studied, in particular because of the possible applications in data storage. In this work, we will investigate a novel method of DW motion using magnetic field pulses, with the precession torque as the driving mechanism. We use a one dimensional (1D) model to show that it is possible to drive DWs in out-of-plane materials using the precession torque, and we identify the key parameters that influence this motion. Because the DW moves back to its initial position at the end of the field pulse, thereby severely complicating direct detection of the DW motion, depinning experiments are used to indirectly observe the effect of the precession torque. The 1D model is extended to include an energy landscape in order to predict the influence of the precession torque in the depinning experiments. Although preliminary experiments did not yet show an effect of the precession torque, our calculations indicate that depinning experiments can be used to demonstrate this novel method of DW motion in out-of-plane materials, which even allows for coherent motion of multiple domains when the Dzyaloshinskii-Moriya interaction is taken into account.
A 1-D model of the nonlinear dynamics of the human lumbar intervertebral disc
Marini, Giacomo; Huber, Gerd; Püschel, Klaus; Ferguson, Stephen J.
2017-01-01
Lumped parameter models of the spine have been developed to investigate its response to whole body vibration. However, these models assume the behaviour of the intervertebral disc to be linear-elastic. Recently, the authors have reported on the nonlinear dynamic behaviour of the human lumbar intervertebral disc. This response was shown to be dependent on the applied preload and amplitude of the stimuli. However, the mechanical properties of a standard linear elastic model are not dependent on the current deformation state of the system. The aim of this study was therefore to develop a model that is able to describe the axial, nonlinear quasi-static response and to predict the nonlinear dynamic characteristics of the disc. The ability to adapt the model to an individual disc's response was a specific focus of the study, with model validation performed against prior experimental data. The influence of the numerical parameters used in the simulations was investigated. The developed model exhibited an axial quasi-static and dynamic response, which agreed well with the corresponding experiments. However, the model needs further improvement to capture additional peculiar characteristics of the system dynamics, such as the change of mean point of oscillation exhibited by the specimens when oscillating in the region of nonlinear resonance. Reference time steps were identified for specific integration scheme. The study has demonstrated that taking into account the nonlinear-elastic behaviour typical of the intervertebral disc results in a predicted system oscillation much closer to the physiological response than that provided by linear-elastic models. For dynamic analysis, the use of standard linear-elastic models should be avoided, or restricted to study cases where the amplitude of the stimuli is relatively small.
Polarization bandgaps and fluid-like elasticity in fully solid elastic metamaterials.
Ma, Guancong; Fu, Caixing; Wang, Guanghao; Del Hougne, Philipp; Christensen, Johan; Lai, Yun; Sheng, Ping
2016-11-21
Elastic waves exhibit rich polarization characteristics absent in acoustic and electromagnetic waves. By designing a solid elastic metamaterial based on three-dimensional anisotropic locally resonant units, here we experimentally demonstrate polarization bandgaps together with exotic properties such as 'fluid-like' elasticity. We construct elastic rods with unusual vibrational properties, which we denote as 'meta-rods'. By measuring the vibrational responses under flexural, longitudinal and torsional excitations, we find that each vibration mode can be selectively suppressed. In particular, we observe in a finite frequency regime that all flexural vibrations are forbidden, whereas longitudinal vibration is allowed-a unique property of fluids. In another case, the torsional vibration can be suppressed significantly. The experimental results are well interpreted by band structure analysis, as well as effective media with indefinite mass density and negative moment of inertia. Our work opens an approach to efficiently separate and control elastic waves of different polarizations in fully solid structures.
Ahn, Young Kwan; Lee, Hyung Jin; Kim, Yoon Young
2017-08-30
Conical refraction, which is quite well-known in electromagnetic waves, has not been explored well in elastic waves due to the lack of proper natural elastic media. Here, we propose and design a unique anisotropic elastic metamaterial slab that realizes conical refraction for horizontally incident longitudinal or transverse waves; the single-mode wave is split into two oblique coupled longitudinal-shear waves. As an interesting application, we carried out an experiment of parallel translation of an incident elastic wave system through the anisotropic metamaterial slab. The parallel translation can be useful for ultrasonic non-destructive testing of a system hidden by obstacles. While the parallel translation resembles light refraction through a parallel plate without angle deviation between entry and exit beams, this wave behavior cannot be achieved without the engineered metamaterial because an elastic wave incident upon a dissimilar medium is always split at different refraction angles into two different modes, longitudinal and shear.
Energy Technology Data Exchange (ETDEWEB)
Wolfenden, R.; Kirkman, S.
1983-02-23
With deuterium present in the formyl group, the equilibrium constant for transfer of N-methylformamide from chloroform to D/sub 2/O at 25/sup 0/C was enhanced by a factor of 3.1 +- 0.15%, as estimated independently by proton magnetic resonance and by double-labeling experiments in which /sup 14/C and /sup 3/H were incorporated alternatively into the methyl group. The distribution coefficient of acetaldehyde-1-d between D/sub 2/O and the vapor phase, on the other hand, differed from that of acetaldehyde by less than 0.5%.
Zhao, Cong; Xiao, Jun; Li, Yong; Chu, Qiyi; Xu, Ting; Wang, Bendong
2017-12-01
As one of the most common process induced defects of automated fiber placement, in-plane fiber waviness and its influences on mechanical properties of fiber reinforced composite lack experimental studies. In this paper, a new approach to prepare the test specimen with in-plane fiber waviness is proposed in consideration of the mismatch between the current test standard and actual fiber trajectory. Based on the generation mechanism of in-plane fiber waviness during automated fiber placement, the magnitude of in-plane fiber waviness is characterized by axial compressive strain of prepreg tow. The elastic constants and tensile strength of unidirectional laminates with in-plane fiber waviness are calculated by off-axis and maximum stress theory. Experimental results show that the tensile properties infade dramatically with increasing magnitude of the waviness, in good agreement with theoretical analyses. When prepreg tow compressive strain reaches 1.2%, the longitudinal tensile modulus and strength of unidirectional laminate decreased by 25.5% and 57.7%, respectively.
Probing hysteretic elasticity in weakly nonlinear materials
Energy Technology Data Exchange (ETDEWEB)
Johnson, Paul A [Los Alamos National Laboratory; Haupert, Sylvain [UPMC UNIV PARIS; Renaud, Guillaume [UPMC UNIV PARIS; Riviere, Jacques [UPMC UNIV PARIS; Talmant, Maryline [UPMC UNIV PARIS; Laugier, Pascal [UPMC UNIV PARIS
2010-12-07
Our work is aimed at assessing the elastic and dissipative hysteretic nonlinear parameters' repeatability (precision) using several classes of materials with weak, intermediate and high nonlinear properties. In this contribution, we describe an optimized Nonlinear Resonant Ultrasound Spectroscopy (NRUS) measuring and data processing protocol applied to small samples. The protocol is used to eliminate the effects of environmental condition changes that take place during an experiment, and that may mask the intrinsic elastic nonlinearity. As an example, in our experiments, we identified external temperature fluctuation as a primary source of material resonance frequency and elastic modulus variation. A variation of 0.1 C produced a frequency variation of 0.01 %, which is similar to the expected nonlinear frequency shift for weakly nonlinear materials. In order to eliminate environmental effects, the variation in f{sub 0} (the elastically linear resonance frequency proportional to modulus) is fit with the appropriate function, and that function is used to correct the NRUS calculation of nonlinear parameters. With our correction procedure, we measured relative resonant frequency shifts of 10{sup -5} , which are below 10{sup -4}, often considered the limit to NRUS sensitivity under common experimental conditions. Our results show that the procedure is an alternative to the stringent control of temperature often applied. Applying the approach, we report nonlinear parameters for several materials, some with very small nonclassical nonlinearity. The approach has broad application to NRUS and other Nonlinear Elastic Wave Spectroscopy approaches.
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.
Acute effect of hemodialysis on arterial elasticity.
Sağ, Saim; Yeşilbursa, Dilek; Yildiz, Abdulmecit; Dilek, Kamil; Şentürk, Tunay; Serdar, Osman Akın; Aydinlar, Ali
2015-01-01
Reduced arterial elasticity is an independent predictor of cardiovascular mortality in patients with end-stage renal disease (ESRD). Hemodialysis (HD) treatment per se can bring additional risk factors for vascular disease. Our study was designed to determine whether a single hemodialysis session leads to an acute alteration in parameters of arterial elasticity in ESRD. In this study, 58 patients undergoing chronic hemodialysis and 29 healthy controls were enrolled. Large artery elasticity index (LAEI) and the small artery elasticity index (SAEI) were measured by applanation tonometry. The acute effect of a hemodialysis session on arterial elasticity indices was assessed by comparison of prehemodialysis and posthemodialysis determinations. At baseline, LAEI did not differ significantly in patients compared with controls. In contrast, the SAEI was significantly lower in patients (4.1 ± 2.6 mL/mmHg x 100) than in healthy individuals (8.9 ± 3.4 mL/mmHg x 100, P < 0.05). In patients with ESRD, no significant changes in LAEI was observed after HD, but SAEI deteriorated significantly (from 4.1 ± 2.6 mL/mmHg x 100 to 3.4 ± 2.3, P < 0.05). We conclude that ESRD patients face a significant reduction in SAEI, which is exacerbated by a dialysis procedure.
Yielding elastic tethers stabilize robust cell adhesion.
Directory of Open Access Journals (Sweden)
Matt J Whitfield
2014-12-01
Full Text Available Many bacteria and eukaryotic cells express adhesive proteins at the end of tethers that elongate reversibly at constant or near constant force, which we refer to as yielding elasticity. Here we address the function of yielding elastic adhesive tethers with Escherichia coli bacteria as a model for cell adhesion, using a combination of experiments and simulations. The adhesive bond kinetics and tether elasticity was modeled in the simulations with realistic biophysical models that were fit to new and previously published single molecule force spectroscopy data. The simulations were validated by comparison to experiments measuring the adhesive behavior of E. coli in flowing fluid. Analysis of the simulations demonstrated that yielding elasticity is required for the bacteria to remain bound in high and variable flow conditions, because it allows the force to be distributed evenly between multiple bonds. In contrast, strain-hardening and linear elastic tethers concentrate force on the most vulnerable bonds, which leads to failure of the entire adhesive contact. Load distribution is especially important to noncovalent receptor-ligand bonds, because they become exponentially shorter lived at higher force above a critical force, even if they form catch bonds. The advantage of yielding is likely to extend to any blood cells or pathogens adhering in flow, or to any situation where bonds are stretched unequally due to surface roughness, unequal native bond lengths, or conditions that act to unzip the bonds.
Yielding Elastic Tethers Stabilize Robust Cell Adhesion
Whitfield, Matt J.; Luo, Jonathon P.; Thomas, Wendy E.
2014-01-01
Many bacteria and eukaryotic cells express adhesive proteins at the end of tethers that elongate reversibly at constant or near constant force, which we refer to as yielding elasticity. Here we address the function of yielding elastic adhesive tethers with Escherichia coli bacteria as a model for cell adhesion, using a combination of experiments and simulations. The adhesive bond kinetics and tether elasticity was modeled in the simulations with realistic biophysical models that were fit to new and previously published single molecule force spectroscopy data. The simulations were validated by comparison to experiments measuring the adhesive behavior of E. coli in flowing fluid. Analysis of the simulations demonstrated that yielding elasticity is required for the bacteria to remain bound in high and variable flow conditions, because it allows the force to be distributed evenly between multiple bonds. In contrast, strain-hardening and linear elastic tethers concentrate force on the most vulnerable bonds, which leads to failure of the entire adhesive contact. Load distribution is especially important to noncovalent receptor-ligand bonds, because they become exponentially shorter lived at higher force above a critical force, even if they form catch bonds. The advantage of yielding is likely to extend to any blood cells or pathogens adhering in flow, or to any situation where bonds are stretched unequally due to surface roughness, unequal native bond lengths, or conditions that act to unzip the bonds. PMID:25473833
Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process.
Li, Fa-Liang; Zhang, Hai-Jun
2017-08-25
The sol-gel method is a simple and facile wet chemical process for fabricating advanced materials with high homogeneity, high purity, and excellent chemical reactivity at a relatively low temperature. By adjusting the processing parameters, the sol-gel technique can be used to prepare hollow sphere and 1D structural materials that exhibit a wide application in the fields of catalyst, drug or gene carriers, photoactive, sensors and Li-ion batteries. This feature article reviewed the development of the preparation of hollow sphere and 1D structural materials using the sol-gel method. The effects of calcination temperature, soaking time, pH value, surfactant, etc., on the preparation of hollow sphere and 1D structural materials were summarized, and their formation mechanisms were generalized. Finally, possible future research directions of the sol-gel technique were outlined.
Synthesis of Hollow Sphere and 1D Structural Materials by Sol-Gel Process
Li, Fa-Liang; Zhang, Hai-Jun
2017-01-01
The sol-gel method is a simple and facile wet chemical process for fabricating advanced materials with high homogeneity, high purity, and excellent chemical reactivity at a relatively low temperature. By adjusting the processing parameters, the sol-gel technique can be used to prepare hollow sphere and 1D structural materials that exhibit a wide application in the fields of catalyst, drug or gene carriers, photoactive, sensors and Li-ion batteries. This feature article reviewed the development of the preparation of hollow sphere and 1D structural materials using the sol-gel method. The effects of calcination temperature, soaking time, pH value, surfactant, etc., on the preparation of hollow sphere and 1D structural materials were summarized, and their formation mechanisms were generalized. Finally, possible future research directions of the sol-gel technique were outlined. PMID:28841188
PC-1D installation manual and user's guide
Energy Technology Data Exchange (ETDEWEB)
Basore, P.A.
1991-05-01
PC-1D is a software package for personal computers that uses finite-element analysis to solve the fully-coupled two-carrier semiconductor transport equations in one dimension. This program is particularly useful for analyzing the performance of optoelectronic devices such as solar cells, but can be applied to any bipolar device whose carrier flows are primarily one-dimensional. This User's Guide provides the information necessary to install PC-1D, define a problem for solution, solve the problem, and examine the results. Example problems are presented which illustrate these steps. The physical models and numerical methods utilized are presented in detail. This document supports version 3.1 of PC-1D, which incorporates faster numerical algorithms with better convergence properties than previous versions of the program. 51 refs., 17 figs., 5 tabs.
1-D Compression Behaviour of Acid Sulphate Soils Treated with Alkali-Activated Slag
Islam, Shahidul; Haque, Asadul; Bui, Ha Hong
2016-01-01
Improvements of soft soils by mechanically mixing cementitious additives have been widely practised for construction of infrastructure. Mixing of additives improves strength and compressibility properties of soils through the development of soil structure. This study investigates the 1-D compression behaviour of alkali-activated slag treated acid sulphate soils (ASS) cured up to 365 days. The void ratio-logarithm of pressure (e-logσ′) behaviour of treated ASS, including the destructuration behaviour, with additive contents and curing time have been analysed. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses have been undertaken to explain the observed variations of the 1-D compression behaviour. This paper presents the results of these analyses in view of obtaining an insight into the 1-D compression behaviour of treated ASS with the help of mineralogical analysis. PMID:28773415
1-D Compression Behaviour of Acid Sulphate Soils Treated with Alkali-Activated Slag
Directory of Open Access Journals (Sweden)
Shahidul Islam
2016-04-01
Full Text Available Improvements of soft soils by mechanically mixing cementitious additives have been widely practised for construction of infrastructure. Mixing of additives improves strength and compressibility properties of soils through the development of soil structure. This study investigates the 1-D compression behaviour of alkali-activated slag treated acid sulphate soils (ASS cured up to 365 days. The void ratio-logarithm of pressure (e-logσ′ behaviour of treated ASS, including the destructuration behaviour, with additive contents and curing time have been analysed. X-ray diffraction (XRD and scanning electron microscopy (SEM analyses have been undertaken to explain the observed variations of the 1-D compression behaviour. This paper presents the results of these analyses in view of obtaining an insight into the 1-D compression behaviour of treated ASS with the help of mineralogical analysis.
3+1D Massless Weyl Spinors from Bosonic Scalar-Tensor Duality
Directory of Open Access Journals (Sweden)
Andrea Amoretti
2014-01-01
Full Text Available We consider the fermionization of a bosonic-free theory characterized by the 3+1D scalar-tensor duality. This duality can be interpreted as the dimensional reduction, via a planar boundary, of the 4+1D topological BF theory. In this model, adopting the Sommerfield tomographic representation of quantized bosonic fields, we explicitly build a fermionic operator and its associated Klein factor such that it satisfies the correct anticommutation relations. Interestingly, we demonstrate that this operator satisfies the massless Dirac equation and that it can be identified with a 3+1D Weyl spinor. Finally, as an explicit example, we write the integrated charge density in terms of the tomographic transformed bosonic degrees of freedom.
rft1d: Smooth One-Dimensional Random Field Upcrossing Probabilities in Python
Directory of Open Access Journals (Sweden)
Todd C. Pataky
2016-07-01
Full Text Available Through topological expectations regarding smooth, thresholded n-dimensional Gaussian continua, random field theory (RFT describes probabilities associated with both the field-wide maximum and threshold-surviving upcrossing geometry. A key application of RFT is a correction for multiple comparisons which affords field-level hypothesis testing for both univariate and multivariate fields. For unbroken isotropic fields just one parameter in addition to the mean and variance is required: the ratio of a field's size to its smoothness. Ironically the simplest manifestation of RFT (1D unbroken fields has rarely surfaced in the literature, even during its foundational development in the late 1970s. This Python package implements 1D RFT primarily for exploring and validating RFT expectations, but also describes how it can be applied to yield statistical inferences regarding sets of experimental 1D fields.
A study of uniform stars using 1/d-expansions and numerical methods
Gaunt, D. S.; Yu, T. C.
2000-02-01
We study a lattice model of an interacting uniform self-avoiding star polymer with f branches. A 1/d -expansion for the limiting reduced free energy is derived through order 1/d for general f and, for f = 3, to order 1/d 2 . The terms in the expansion are independent of f and agree term by term with the corresponding expansion for interacting self-avoiding walks. We also present a miscellany of numerical results obtained by more conventional series and Monte Carlo techniques. All our results, both past and present, support the conjecture that the limiting reduced free energies of f -stars, walks and polygons are identical for all values of the interaction parameter icons/Journals/Common/beta" ALT="beta" ALIGN="TOP"/> .
Dynamical Analysis and Big Bang Bifurcations of 1D and 2D Gompertz's Growth Functions
Rocha, J. Leonel; Taha, Abdel-Kaddous; Fournier-Prunaret, D.
In this paper, we study the dynamics and bifurcation properties of a three-parameter family of 1D Gompertz's growth functions, which are defined by the population size functions of the Gompertz logistic growth equation. The dynamical behavior is complex leading to a diversified bifurcation structure, leading to the big bang bifurcations of the so-called “box-within-a-box” fractal type. We provide and discuss sufficient conditions for the existence of these bifurcation cascades for 1D Gompertz's growth functions. Moreover, this work concerns the description of some bifurcation properties of a Hénon's map type embedding: a “continuous” embedding of 1D Gompertz's growth functions into a 2D diffeomorphism. More particularly, properties that characterize the big bang bifurcations are considered in relation with this coupling of two population size functions, varying the embedding parameter. The existence of communication areas of crossroad area type or swallowtails are identified for this 2D diffeomorphism.
Northern Korean Peninsula 1-D velocity model from surface wave dispersion and full-waveform data
Lee, S. J.; Rhie, J.; Kim, S.; Kang, T. S.; Cho, C.
2016-12-01
Monitoring seismic activities in the northern Korean Peninsula is important not only for understanding the characteristics of earthquakes but also for watching nuclear tests. To better monitor those natural and man-made seismic activities, reliable seismic velocity models are required. However, the seismic velocity structure of the region is not known well due to the lack of available seismic data directly measured in the region. This study presents 1-D velocity models of the region using two different datasets comprised of two-year-long continuous waveform and the 2013 North Korea nuclear test event waveform recorded at stations surrounding the region. Two reference 1-D models for the inland and offshore areas (Western East Sea) were estimated by 1-D inversion of surface wave dispersion measurements from ambient noise cross-correlations of the continuous waveform. To investigate the variations in the velocity models, many 1-D models for the paths between the 2013 nuclear test site and stations in China and South Korea were constructed by forward waveform modeling. The velocity variations are not significant for both models representing the inland and offshore paths, respectively. The 1-D models for the inland paths are similar to the models constructed for the southern Korean Peninsula. Interestingly, waveforms sampling through the offshore paths are not well explained by simple 1-D isotropic models. The preliminary result indicates that there exists radial anisotropy with SH being faster than SV by 3-5% in the upper mantle beneath the offshore northern Korean Peninsula, although further studies are necessary to explain the origin of anisotropy. A proper characterization of propagation effects along the offshore paths would be useful for monitoring future nuclear tests because many seismic stations in the eastern South Korea record waveforms sampling the offshore region from the nuclear test site to those stations.
Regulation of DNA methylation on EEF1D and RPL8 expression in cattle.
Liu, Xuan; Yang, Jie; Zhang, Qin; Jiang, Li
2017-10-01
Dynamic changes to the epigenome play a critical role in a variety of biology processes and complex traits. Many important candidate genes have been identified through our previous genome wide association study (GWAS) on milk production traits in dairy cattle. However, the underlying mechanism of candidate genes have not yet been clearly understood. In this study, we analyzed the methylation variation of the candidate genes, EEF1D and RPL8, which were identified to be strongly associated with milk production traits in dairy cattle in our previous studies, and its effect on protein and mRNA expression. We compared DNA methylation profiles and gene expression levels of EEF1D and RPL8 in five different tissues (heart, liver, mammary gland, ovary and muscle) of three cows. Both genes showed the highest expression level in mammary gland. For RPL8, there was no difference in the DNA methylation pattern in the five tissues, suggesting no effect of DNA methylation on gene expression. For EEF1D, the DNA methylation levels of its first CpG island differed in the five tissues and were negatively correlated with the gene expression levels. To further investigate the function of DNA methylation on the expression of EEF1D, we collected blood samples of three cows at early stage of lactation and in dry period and analyzed its expression and the methylation status of the first CpG island in blood. As a result, the mRNA expression of EEF1D in the dry period was higher than that at the early stage of lactation, while the DNA methylation level in the dry period was lower than that at the early stage of lactation. Our result suggests that the DNA methylation of EEF1D plays an important role in the spatial and temporal regulation of its expression and possibly have an effect on the milk production traits.
Vitamin D Receptor Gene Polymorphisms Influence T1D Susceptibility among Pakistanis
Mukhtar, Maryam; Batool, Andleeb; Wajid, Abdul; Qayyum, Iram
2017-01-01
Background. The vitamin D receptor (VDR) gene regulates insulin secretion from the pancreas and acts as a mediator of the immune response through vitamin D. Polymorphism in VDR causes alterations in the functioning of vitamin D, leading to type 1 diabetes (T1D) predisposition. The aim of the present study was to determine VDR gene polymorphism in association with T1D in Pakistanis. Methods. The association was evaluated by selecting rs2228570 (FokΙ), rs7975232 (ApaΙ), and rs731236 (TaqΙ) poly...
On the potentialities of 3D-1D coupled models in hemodynamics simulations.
Blanco, P J; Pivello, M R; Urquiza, S A; Feijóo, R A
2009-05-11
This work comprises a step towards the quantitative and qualitative analysis of coupled local and global hemodynamics phenomena in the arterial system. The aim of this work is to present some numerical examples to put in evidence the importance of the use of 3D-1D coupled models in hemodynamics problems when carrying out simulations of rather complex situations. Accordingly, some cases for which classical modeling cannot be applied are identified and solved. The results obtained here allow us to assess some interrelations between local pointwise quantities (defined at the level of the 3D model) and global mean quantities (defined at the level of the 1D model).
On the origin of multi-step spin transition behaviour in 1D nanoparticles
Chiruta, Daniel; Jureschi, Catalin-Maricel; Linares, Jorge; Dahoo, Pierre Richard; Garcia, Yann; Rotaru, Aurelian
2015-09-01
To investigate the spin state switching mechanism in spin crossover (SCO) nanoparticles, a special attention is given to three-step thermally induced SCO behavior in 1D chains. An additional term is included in the standard Ising-like Hamiltonian to account for the border interaction between SCO molecules and its local environment. It is shown that this additional interaction, together with the short range interaction, drives the multi-steps thermal hysteretic behavior in 1D SCO systems. The relation between a polymeric matrix and this particular multi-step SCO phenomenon is discussed accordingly. Finally, the environmental influence on the SCO system's size is analyzed as well.
Dopamine D1-D2 receptor heteromer signaling pathway in the brain: emerging physiological relevance
Directory of Open Access Journals (Sweden)
Hasbi Ahmed
2011-06-01
Full Text Available Abstract Dopamine is an important catecholamine neurotransmitter modulating many physiological functions, and is linked to psychopathology of many diseases such as schizophrenia and drug addiction. Dopamine D1 and D2 receptors are the most abundant dopaminergic receptors in the striatum, and although a clear segregation between the pathways expressing these two receptors has been reported in certain subregions, the presence of D1-D2 receptor heteromers within a unique subset of neurons, forming a novel signaling transducing functional entity has been shown. Recently, significant progress has been made in elucidating the signaling pathways activated by the D1-D2 receptor heteromer and their potential physiological relevance.
Szewczyk, Dawid; Bauer, Andreas; Holt, Rune M.
2018-01-01
some of the cases higher stress-sensitivity of elastic properties can be seen in the direction parallel to the bedding plane.
Transverse plane gait problems in children with cerebral palsy.
Rethlefsen, Susan A; Kay, Robert M
2013-06-01
Transverse plane deviations are significant contributors to pathologic gait in children with cerebral palsy (CP). Due to limitations in neuromuscular control, balance, strength and coordination, transverse plane gait deviations are poorly tolerated in these children. Transverse plane malalignment results in lever arm dysfunction and can be seen with either intoeing or out-toeing. Frequent causes of transverse plane problems and lever arm dysfunction include long bone (femoral and/or tibial) torsion, pelvic rotation, and pes varus or valgus. Computerized motion analysis facilitates accurate identification of transverse plane abnormalities. This article addresses appropriate identification and treatment of transverse plane gait deviations in children with CP.