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  • 1
    Electronic Resource
    Electronic Resource
    Elasticity of the pyrope (Mg3Al2Si3O12)-majorite (MgSiO3) garnets solid solution (2000)
    Springer
    Physics and chemistry of minerals 27 (2000), S. 445-452 
    Details
    ISSN: 1432-2021
    Keywords: Keywords Garnets ; Polycrystals ; Hot-pressing ; Elasticity ; Interferometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: Abstract Dense isotropic polycrystalline specimens of majorite-rich garnets (Py100, Py62Mj38, Py50Mj50, Py21Mj79 and Mj100) along the pyrope (Mg3Al2Si3O12 = Py100)-majorite (MgSiO3 = Mj100) join were fabricated in a 2000-ton uniaxial split-sphere anvil apparatus (USSA-2000) at pressures from 10 to 18.5 GPa and temperatures from 1200 to 1850 °C, within their stability fields in runs of 2–4-h duration, using hot-pressing techniques developed by Gwanmesia et al. (1993). These specimens are single-phased, fine-grained (≤5 mm), free of microcracks, and have bulk densities greater than 99% of the corresponding single-crystal X-ray density. Elastic compressional (P) and shear (S) wave velocities were determined at room pressure and temperature for these polycrystalline garnet specimens by phase comparison ultrasonic interferometry. For Mj100, the P and S wave velocities are within 1% of the Hashin-Shtrikman averages calculated from the single crystal elastic moduli measured by Brillouin spectroscopy. Both the elastic bulk modulus (K) and the shear modulus (G) decrease continuously with increasing majorite content from pyrope garnet (Py100) to pure majorite garnet (Mj100). The compositional dependence of K and G are given by K = 172.3 (40) − 0.085X, and G = 91.6 (10) − 0.038X, where X = mol% majorite), respectively, indicating that substitution of Si for Mg and Al decreases both K and G by about 5% along the solid solution series.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002699900054
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  • 2
    Electronic Resource
    Electronic Resource
    Measurement of the elasticity of the actin tail of Listeria monocytogenes (2000)
    Springer
    European biophysics journal 29 (2000), S. 134-140 
    Details
    ISSN: 1432-1017
    Keywords: Key wordsListeria monocytogenes ; Cell motility ; Actin gel ; Elasticity ; Optical tweezers ; Cell mechanics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Abstract We report biophysical experiments performed on the bacterium Listeria monocytogenes, a model system to study actin-based motility. Using optical tweezers and electrophoresis experiments, we find that the bacterium is firmly attached to its tail, and we demonstrate that the tail responds as an elastic gel when deformed. We have measured its elastic modulus at a value of 103–104 Pa, which is 10 times higher than the rigidity of the eukaryotic cytoplasm. These results demonstrate that the bacterium and its tail form a very robust system, consistent with the steadyness of the motion observed in vivo. We propose an elastic model for the propulsion mechanism which takes into account the connection and thus the interaction between the actin filaments. It provides a generic description of the various aspects of actin-tail based movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002490050258
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  • 3
    Electronic Resource
    Electronic Resource
    Shear circular dislocation loops investigated with elasticity theory and atomistic simulations (2000)
    Springer
    Journal of computer-aided materials design 7 (2000), S. 25-42 
    Details
    ISSN: 1573-4900
    Keywords: Copper ; Dislocation ; Elasticity ; Molecular dynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The elastic fields of displacements, strains, and stresses for a shear circular loop are obtained with the Burgers formula. In addition, interactions between two shear circular loops are obtained based on elasticity theory. A series of molecular dynamics (MD) simulations on a shear circular partial dislocation loop in copper have been performed to examine the elastic solutions. It is found that the results of the MD simulations are in good agreement with those of elasticity theory for a loop with radius ∼7.5 nm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008766500345
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  • 4
    Electronic Resource
    Electronic Resource
    Complex hypersingular integral equation for the piece-wise homogeneous half-plane with cracks (2000)
    Springer
    International journal of fracture 102 (2000), S. 177-204 
    Details
    ISSN: 1573-2673
    Keywords: Elasticity ; half-plane ; boundary integral equations ; hypersingular.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract New complex hypersingular integral equation (CHSIE) is derived for the half-plane containing the inclusions (which can have the different elastic properties), holes, notches and cracks of the arbitrary shape. This equation is obtained by superposition of the equations for each homogeneous region in a half-plane. The last equations follow from the use of complex analogs of Somigliana's displacement and stress identities (SDI and SSI) and Melan's fundamental solution (FS) written in a complex form. The universal numerical algorithm suggested before for the analogous problem for a piece-wise homogeneous plane is extended on case of a half plane. The unknown functions are approximated by complex Lagrange polynomials of the arbitrary degree. The asymptotics for the displacement discontinuities (DD) at the crack tips are taken into account. Only two types of the boundary elements (straight segments and circular arcs) are used to approximate the boundaries. All the integrals involved in CHSIE are evaluated in a closed form. A wide range of elasticity problems for a half-plane with cracks, openings and inclusions are solved numerically.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007633814813
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  • 5
    Electronic Resource
    Electronic Resource
    Interaction among a row of ellipsoidal inclusions (2000)
    Springer
    International journal of fracture 102 (2000), S. 371-392 
    Details
    ISSN: 1573-2673
    Keywords: Elasticity ; body force method ; singular integral equations ; numerical analysis ; three-dimensional analysis ; stress concentration factor ; ellipsoidal inclusion.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract In this paper the interaction among a row of N ellipsoidal inclusions of revolution is considered. Inclusions in a body under both (A) asymmetric uniaxial tension in the x-direction and (B) axisymmetric uniaxial tension in the z-direction are treated in terms of singular integral equations resulting from the body force method. These problems are formulated as a system of singular integral equations with Cauchy-type or logarithmic-type singularities, where unknowns are densities of body forces distributed in the r,θ,z directions. In order to satisfy the boundary conditions along the ellipsoidal boundaries, the unknown functions are approximated by a linear combination of fundamental density functions and polynomials. The present method is found to yield rapidly converging numerical results for interface stresses. When the elastic ratio E 1⇒E I/E M〉1, the primary feature of the interaction is a large compressive or tensile stress σn on the interface θ=0. When E 1⇒E I/E M〈1, a large tensile stress σθ or σt on the interface θ=1/2π is of interest. If the spacing b/d and the elastic ratio E I/E M are fixed, the interaction effects are dominant when the shape ratio a/b is large. For any fixed shape and spacing of inclusions, the maximum stress is shown to be linear with the reciprocal of the squared number of inclusions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007604809440
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  • 6
    Electronic Resource
    Electronic Resource
    A Note on Elasticity and Price Dispersions in the Music Recording Industry (2000)
    Springer
    Review of industrial organization 17 (2000), S. 465-470 
    Details
    ISSN: 1573-7160
    Keywords: Elasticity ; music recording industry ; oligopoly ; price dispersions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Economics
    Notes: Abstract The present note examines price dispersions inthe music recording industry between new release andmid-line (older) recordings. The model employs theframework developed within the industrial economicsliterature and provides empirical results suggestingthat new release prices are lower than those ofmid-level recordings. This result follows fromdiffering buyer characteristics and varying levelsof close substitutes, leading to higher demandelasticities for new release recordings. Finally,the theoretical expectations should hold in thepresence of either significant scale economies ormodest minimum efficient scales of production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007820616596
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  • 7
    Electronic Resource
    Electronic Resource
    Rheological properties of fresh and cryopreserved human arteries tested in vitro (2000)
    Springer
    Rheologica acta 39 (2000), S. 461-468 
    Details
    ISSN: 1435-1528
    Keywords: Key words In vitro tests ; Elasticity ; Human artery ; Cryopreservation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Abstract Cryopreservation is widely used to preserve blood vessels for a while but is controversially suspected to affect the mechanical behavior of these allografts. The aim of this study was to determine whether differences in the three-dimensional mechanical behavior exist or not between fresh and cryopreserved arteries. Using a previously developed experimental system, in vitro inflation tests were performed on twenty segments of human fresh and cryopreserved arteries, in static conditions. Opening angles were also measured from images of rings in zero-stress state. The initial reference state was chosen as the unloaded state and tests were performed on specimens stretched at natural “in vivo” length. Mechanical measures calculated are “natural” (Hencky) strains (finite deformations), “true” (Cauchy) stresses in radial, circumferential, and longitudinal directions as well as strain energy per unit volume. Tangent moduli are derived from radial and circumferential stress-strain characteristics using non-linear curve fitting. Values of incremental and pressure-strain elastic parameters, wall stiffness, and compliance per unit length are also calculated. Results are presented in terms of characteristics of stresses and strains in the three directions, axial force, tangent moduli vs strains or stresses, and energy per unit volume, for both types of artery, with reference to transmural pressure. Detailed numerical results are given at mean transmural pressure or in the physiological range. Significant differences are indicated by statistic Student T-tests. Results obtained show that significant differences exist between rheological properties of fresh and cryopreserved segments of human artery. Strains, stresses, axial force, strain energy, and wall stiffness values highlight those differences whereas elastic parameters, compliance, and opening angle do not. The usefulness of some parameters to compare the mechanical behavior existing between fresh and cryopreserved arteries is therefore underlined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003970000110
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  • 8
    Electronic Resource
    Electronic Resource
    Application of a new separation analyzer for the characterization of dispersions stabilized with clay derivatives (2000)
    Springer
    Colloid & polymer science 278 (2000), S. 369-374 
    Details
    ISSN: 1435-1536
    Keywords: Key words Separation analyzer ; Organoclay dispersions ; Elasticity ; Emulsion stability ; Emulsions stabilized by clay derivatives
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The performance of a newly developed separation analyzer is demonstrated by characterization of the sedimentation kinetics and the swelling behavior of organoclays in binary solvent mixtures (toluene/cyclohexane) as well as by investigation of oil-in-water and water-in-oil emulsions stabilized by clay derivatives. The automatic measuring system – LUMiFuge 114 – is based on a special centrifuge with an integrated optoelectronic sensor system which allows the measuring of spatial and temporal changes of light transmission during the rotation in a variable centrifugal field (12–1200g). By using the new device a fast and reproducible characterization of settling behavior and dispersion stability was possible. Moreover, the evaluation of the long-term stability of samples with high separation stability as well as of the heterogenity of the separation process, the sample transparency and the elasticity of the sediment as a function of alternating centrifugal force could be carried out.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003960050527
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  • 9
    Electronic Resource
    Electronic Resource
    Anisotropy of Young's modulus of human tibial cortical bone (2000)
    Springer
    Medical & biological engineering & computing 38 (2000), S. 333-338 
    Details
    ISSN: 1741-0444
    Keywords: Biomechanics ; Cortical bone ; Young's modulus ; Anisotropy ; Elasticity ; Ultrasonics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The anisotropy of Young's modulus in human cortical bone was determined for all spatial directions by performing coordinate rotations of a 6 by 6 elastic stiffness matrix. The elastic stiffness coefficients were determined experimentally from ultrasonic velocity measurements on 96 samples of normal cortical bone removed from the right tibia of eight human cadavers. The following measured values were used for our analysis: c 11 =19.5 GPa, c 22 =20.1 GPa, c 33 =30.9 GPa, c 44 =5.72 GPa, c 55 =5.17 GPa, c 66 =4.05 GPa, c 23 =12.5 GPa. The remaining coefficients were determined by assuming that the specimens possessed at least an orthorhombic elastic symmetry, and further assuming that c 13 =c 23 , c 12 =c 11 –2c 66 . Our analysis revealed a substantial anisotropy in Young's modulus in the plane containing the long axis of the tibia, with maxima of 20.9 GPa parallel to the long axis, and minima of 11.8 GPa perpendicular to this axis. A less pronounced anisotropy was observed in the plane perpendicular to the long axis of the tibia. To display our results for the full three-dimensional anisotropy of cortical bone, a closed surface was used to represent Young's modulus in all spatial directions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02347055
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  • 10
    Electronic Resource
    Electronic Resource
    Controllability and Stabilization in Elasticity, Heat Conduction and Thermoelasticity: Review of Recent Developments* (2000)
    Springer
    Journal of global optimization 17 (2000), S. 353-386 
    Details
    ISSN: 1573-2916
    Keywords: Approximation ; Elasticity ; Exact and approximate controllability ; Heat equations ; Stabilization ; Thermoelasticity ; Thermoviscoelasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract The aim of this paper is to review developments in exact and approximate controllability as well as stabilization of elastic, thermoelastic, and thermo-viscoelastic bodies. Heat equations are also discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026596405554
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  • 11
    Electronic Resource
    Electronic Resource
    Generalized stress intensity factors in the interaction between two fibers in matrix (2000)
    Springer
    International journal of fracture 103 (2000), S. 19-39 
    Details
    ISSN: 1573-2673
    Keywords: Elasticity ; composite material ; fracture mechanics ; fiber ; generalized stress intensity factor ; end effect ; interaction ; rectangular inclusions.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract To evaluate the mechanical strength of fiber reinforced composites it is necessary to consider singular stresses at the end of fibers because they cause crack initiation, propagation, and final failure. The singular stress is expressed by generalized stress intensity factors defined at the corner of fibers. As a 2D model an interaction between rectangular inclusions under longitudinal tension is treated in this paper. The body force method is used to formulate the problem as a system of singular integral equations with Cauchy-type or logarithmic-type singularities, where the unknown functions are the densities of body forces distributed in infinite plates having the same elastic constants as those of the matrix and inclusions. In order to analyze the problem accurately, the unknown functions are expressed as piecewize smooth functions using two types of fundamental densities and power series, where the fundamental densities are chosen to represent the symmetric stress singularity of 1/r 1−λ 1 and the skew-symmetric stress singularity of 1/r 1−λ 2. Then, generalized stress intensity factors at the end of inclusions are systematically calculated for various locations, spacings and elastic modulus of two rectangular inclusions in a plate subjected to longitudinal tension.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007696723382
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