Showing papers on "Elasticity (economics) published in 1978"
TL;DR: In this article, the authors considered some equilibrium finite element methods for two-dimensional elasticity problems and established L 2-estimates of orderO(h 2 ) for both stresses and displacements.
Abstract: We consider some equilibrium finite element methods for two-dimensional elasticity problems. The stresses and the displacements are approximated by using piecewise linear functions. We establishL 2-estimates of orderO(h 2) for both stresses and displacements.
188 citations
TL;DR: In this article, the authors compared the price predictions of the elasticity and monetary theories of balance of payments adjustment with actual price behavior, and found that price levels tended to rise with appreciations and fall with depreciations.
172 citations
TL;DR: In this article, the elastic constants of orthoenstatite have been determined from Brillouin-scattering measurements, and they are c 11 = 2.247, c 22 = 1.527, c 31 = 0.541 and c 12 = 0.724 Mbar.
167 citations
TL;DR: In this paper, the authors discuss the measurement of elasticity of factor substitution and bias of technical change, and provide necessary conditions for observations to be consistent with the factor augmentation hypothesis, and give limits on the values of the elasticity and bias required for consistency.
Abstract: Publisher Summary This chapter discusses the measurement of elasticity of factor substitution and bias of technical change. Empirical studies of the relationships between disembodied technical change and aggregate economic growth have frequently measured the rate of technical progress. The identifiability of the elasticity and bias will depend on what is in fact true about the economy and on what the economist assumes a priori to be true. One possible outcome of an econometric experiment is an inconsistency of the maintained hypothesis with the observations. The assumption that technical progress is factor augmenting is frequently employed in empirical work. The chapter provides necessary conditions for observations to be consistent with the factor augmentation hypothesis, and gives limits on the values of the elasticity and bias required for consistency. Inner bounds on the range of indeterminacy of the elasticity and bias are established in the case that the factor augmentation hypothesis is true.
164 citations
TL;DR: In this article, a criterion is presented which assures that a bilinear system may be stabilized with a feedback control which yields the feedback system globally asymptotically stable.
Abstract: A criterion is presented which assures that a bilinear system may be stabilized with a feedback control which yields the feedback system globally asymptotically stable. Applications to stabilization of columns with follower load are presented.
122 citations
TL;DR: In this paper, a brief introduction to the nonlinear theory of elasticity is given, followed by a detailed discussion of the underlying boundary value problems and a discussion demonstrates why this theory is far more difficult than most nonlinear theories of mathematical physics.
Abstract: Publisher Summary This chapter gives a brief introduction to the nonlinear theory of elasticity It presents a concise derivation of the basic equations followed by a detailed discussion of the underlying boundary value problems The discussion demonstrates why this theory is far more difficult than most nonlinear theories of mathematical physics The notation used in the chapter is summarized in a tabulated form The material time derivative is defined in the chapter A discussion is presented in the chapter on mass distribution, reference density, system of forces, surface forces, body forces, and the balance of momentum The salient features of the equation of elasticity are compared with those of the Navier–Stokes equations The elasticity tensor is defined, the boundary value problems of elastostatics are discussed, and the displacement problem is also elaborated in the chapter
93 citations
85 citations
TL;DR: It is explained how complete connectivity conditions can be used to replace boundary integral equations in many situations, and it is shown that completeness is satisfied not only in steady-state problems such as potential, reduced wave equation and static and quasi-static elasticity, but also in time-dependent problemssuch as heat and wave equations and dynamical elasticity.
Abstract: In previous papers Herrera developed a theory of connectivity that is applicable to the problem of connecting solutions defined in different regions, which occurs when solving partial differential equations and many problems of mechanics. In this paper we explain how complete connectivity conditions can be used to replace boundary integral equations in many situations. We show that completeness is satisfied not only in steady-state problems such as potential, reduced wave equation and static and quasi-static elasticity, but also in time-dependent problems such as heat and wave equations and dynamical elasticity. A method to obtain bases of connectivity conditions, which are independent of the regions considered, is also presented.
77 citations
Patent•
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31 Jul 1978
TL;DR: In this article, a length of tissue strip is drawn from a roll of tissue immersed partly in and moistened with a suitable liquid through a fine diameter tissue drawing hole formed through a wet tissue drawing member made of a material having high elasticity.
Abstract: A wet tissue container wherein a length of tissue strip is drawn from a roll of tissue immersed partly in and moistened with a suitable liquid through a fine diameter tissue drawing hole formed through a wet tissue drawing member made of a material having high elasticity.
76 citations
TL;DR: In this paper, exact expressions for the stresses and the displacements in an infinite elastic solid containing two spherical inclusions are presented when an arbitrary linear strain field is applied at infinity, and the analysis is based on the Boussinesq-Papkovich stress function approach and makes use of the multipole expansion technique in which the solutions are expanded into series of spherical harmonics with respect to the centers of the two spheres.
72 citations
TL;DR: Flow pattern observations in circular die entry flows in conjunction with independent shear and normal stress measurement strongly suggest that these fluids would make excellent model fluids for melt studies.
Abstract: Shear stress and first normal stress difference data are presented for materials which exhibit a constant viscosity and yet at the same time exhibit elasticity levels of the same order as polymer melts. Flow pattern observations in circular die entry flows in conjunction with independent shear and normal stress measurement strongly suggest that these fluids would make excellent model fluids for melt studies. Studies in which the influence of elasticity in the absence of shear thinning and fluid inertia can easily be made. Furthermore it is clearly shown that a realistic solution to the die entry flow problem is not obtained using second order flow theory. In the second order region the secondary cell is observed to be almost identical in size to the cell observed for an inelastic Newtonian fluid in creeping flow. Marked growth in the secondary cell as a function of elasticity is not observed until the shear rates exceed the region of second order behavior. This growth in cell size as a result of elasticity is followed at higher shear rates by a spiraling flow instability like that observed for some polymer melts.
TL;DR: In this article, the authors showed that the use of Saint-Venant's principle in the solution of elasticity problems for sandwich type structures is not justified in general, and that the exponential decay of end effects is characterized in terms of a complex eigenvalue.
Patent•
25 Apr 1978
TL;DR: In this paper, a cylinder is rigidly secured to a frame oscillating according to a vertical axis and mechanically connected to an electromagnetic device generating a reaction force; the frame is also connected to a linear electromagnetic transducer suitable to supply signals to a thromboelastogram recording apparatus.
Abstract: Apparatus for determining blood elasticity parameters, comprising a cylinder suitable to be immersed in a blood container subjected to regular oscillations. The cylinder is rigidly secured to a frame oscillating according to a vertical axis and mechanically connected to an electromagnetic device generating a reaction force; the frame is also connected to a linear electromagnetic transducer suitable to supply signals to a thromboelastogram recording apparatus.
TL;DR: It is concluded that Richards’ method should not be used when accuracy is deemed important, because it usually overestimates osmotic pressure and sometimes underestimates turgor pressure.
Abstract: The pressure bomb is being used to a much greater extent to measure some tissue – water relations parameters such as osmotic pressure, turgor pressure, and cell wall elasticity. Recently, Richards has developed a faster pressure-bomb method of obtaining these and other parameters than the method used by Hammel and modified by us. In this paper, we compare the two methods and conclude that Richards’ method should not be used when accuracy is deemed important. The Richards method usually overestimates osmotic pressure by 0.2 MPa (= 2 bars) and sometimes by 0.8 MPa (= 8 bars).
TL;DR: In this article, the configuration of a Z-shaped crack is defined by a web length, two flange lengths, and two flane-web angles, and the associated elasticity problems are solved asymptotically in terms of this small parameter.
Abstract: The configuration of a Z-shaped crack is defined by a web length, two flange lengths, and two flange-web angles. A Z-shaped crack is said to be slender if the flange-web ratios are small. These ratios may then be characterized by a slenderness parameter e. The associated elasticity problems are solved asymptotically in terms of this small parameter. Formal asymptotic expansions are developed, and explicit procedures are given for obtaining a solution accurate to the order of e. This solution is fundamental to the determination of the maximum energy-release rate in linear clastic fracture mechanics. Using the maximum-energy-release-rate criterion, a tension-compression specimen with a crack is studied in the accompanying paper.
TL;DR: In this article, the interlaminar stresses generated in a four layer [45, −45] and [θ, 0, 0, 0, θ] laminate in uniform bending are presented.
TL;DR: In this article, a simple labour supply model that incorporates commuting time in a utility maximizing framework was proposed, and the elasticity of housing prices with respect to the latter is estimated to be about 10 percent.
TL;DR: In this paper, a general analytic framework is described in which estimators of the elasticity of capital-labor substitution and other production parameters can be examined for specification bias, and tests are developed for the following sources of possible bias in the usual cross-section estimates of industry production functions: (1) nonconstant returns to scale and nonhomotheticity in production, (2) inclusion of productive factors other than capital and labor, particularly raw materials, (3) variations in output prices faced by firms, and (4) non-constancy of substitution.
Abstract: Publisher Summary This chapter describes a general analytic framework in which estimators of the elasticity of capital-labor substitution and other production parameters can be examined for specification bias. Econometric methods are devised for testing the production model against specific alternatives of interest. In particular, tests are developed for the following sources of possible bias in the usual cross-section estimates of industry production functions: (1) nonconstant returns to scale and nonhomotheticity in production, (2) inclusion of productive factors other than capital and labor, particularly raw materials, (3) variations in output prices faced by firms, and (4) nonconstancy of the elasticity of substitution. The chapter discusses a useful reformulation of production possibilities in terms of cost functions and describes the elasticity of substitution. It also discusses the assumptions underlying the usual estimation procedures and evidence in the literature concerning their validity.
Journal Article•
TL;DR: In this article, the differential production approach is applied to world trade matrices of 1971 and 1975, which yields a price elasticity estimate of the demand for foreign food of about −0.7.
TL;DR: In this article, the application of boundary element method in elasticity is described, starting by discussing the basic weighted residual expressions, together with the numerical integration schemes for three dimensional elasticity and specialized to two dimensional case.
TL;DR: In this article, uniaxial tension and compression experiments are reported on crosslinked poly(dimethylsiloxane) networks in the unswollen state over the range 0.5 1 region with decreasing slope.
Abstract: Results of uniaxial tension and compression experiments are reported on crosslinked poly(dimethylsiloxane) networks in the unswollen state over the range 0.5 1 region with decreasing slope. These results are in agreement with the predictions of recent elasticity theories that incorporate the effect of junction-chain entanglements in the elastic free energy.
Posted Content•
TL;DR: In this paper, the authors discuss the measurement of elasticity of factor substitution and bias of technical change, and provide necessary conditions for observations to be consistent with the factor augmentation hypothesis, and give limits on the values of the elasticity and bias required for consistency.
Abstract: Publisher Summary This chapter discusses the measurement of elasticity of factor substitution and bias of technical change. Empirical studies of the relationships between disembodied technical change and aggregate economic growth have frequently measured the rate of technical progress. The identifiability of the elasticity and bias will depend on what is in fact true about the economy and on what the economist assumes a priori to be true. One possible outcome of an econometric experiment is an inconsistency of the maintained hypothesis with the observations. The assumption that technical progress is factor augmenting is frequently employed in empirical work. The chapter provides necessary conditions for observations to be consistent with the factor augmentation hypothesis, and gives limits on the values of the elasticity and bias required for consistency. Inner bounds on the range of indeterminacy of the elasticity and bias are established in the case that the factor augmentation hypothesis is true.