154,429 research outputs found

    The third order elastic constants of nacl and kcl single crystals

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    Ultrasonic wave velocity measurements for determining third-order elastic constants of sodium and potassium chloride single crystal

    Finite element analysis of laminated plates and shells, volume 1

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    The finite element method is used to investigate the static behavior of laminated composite flat plates and cylindrical shells. The analysis incorporates the effects of transverse shear deformation in each layer through the assumption that the normals to the undeformed layer midsurface remain straight but need not be normal to the mid-surface after deformation. A digital computer program was developed to perform the required computations. The program includes a very efficient equation solution code which permits the analysis of large size problems. The method is applied to the problem of stretching and bending of a perforated curved plate

    Fitting Precision Electroweak Data with Exotic Heavy Quarks

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    The 1999 precision electroweak data from LEP and SLC persist in showing some slight discrepancies from the assumed standard model, mostly regarding bb and cc quarks. We show how their mixing with exotic heavy quarks could result in a more consistent fit of all the data, including two unconventional interpretations of the top quark.Comment: 7 pages, no figure, 2 typos corrected, 1 reference update

    Microwave emission from dry and wet snow

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    A microscopic model was developed to study the microwave emission from snow. In this model, the individual snow particles are considered to be the scattering centers. Mie scattering theory for spherical particles is then used to compute the volume scattering and extinction coefficients of the closely packed scattering spheres, which are assumed not to interact coherently. The results of the computations show significant volume scattering effects in the microwave region which result in low observed emissivities from cold, dry snow. In the case of wet snow, the microwave emissivities are increased considerably, in agreement with earlier experimental observations in which the brightness temperatures have increased significantly at the onset of melting

    Combustion: Structural interaction in a viscoelastic material

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    The effect of interaction between combustion processes and structural deformation of solid propellant was considered. The combustion analysis was performed on the basis of deformed crack geometry, which was determined from the structural analysis. On the other hand, input data for the structural analysis, such as pressure distribution along the crack boundary and ablation velocity of the crack, were determined from the combustion analysis. The interaction analysis was conducted by combining two computer codes, a combustion analysis code and a general purpose finite element structural analysis code

    Rational Approximate Symmetries of KdV Equation

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    We construct one-parameter deformation of the Dorfman Hamiltonian operator for the Riemann hierarchy using the quasi-Miura transformation from topological field theory. In this way, one can get the approximately rational symmetries of KdV equation and then investigate its bi-Hamiltonian structure.Comment: 14 pages, no figure

    Shifting RbR_b with AFBbA^b_{FB}

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    Precision measurements at the ZZ resonance agree well with the standard model. However, there is still a hint of a discrepancy, not so much in RbR_b by itself (which has received a great deal of attention in the past several years) but in the forward-backward asymmetry AFBbA^b_{FB} together with RbR_b. The two are of course correlated. We explore the possibilty that these and other effects are due to the mixing of bLb_L and bRb_R with one or more heavy quarks.Comment: 11 pages, 1 Figure, LaTex fil
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