53,179 research outputs found
On iterative solutions for quantum-mechanical bound states
Iterative solutions for quantum mechanical bound state
Heat flux sensor design reduces extraneous source effects
Heat flux sensor isolates the sensor and its transmitting thermocouple from undesirable heat sources by incorporating a radiator section that forms a radiation shield between mounting cup and sensor. Bonding of the thermocouple cable to the underside of the radiator provides a conductive path to dissipate extraneous heat that might otherwise reach the sensor
Heat flux sensor assembly
Heat flux sensor assembly with proviso for heat shield to reduce radiative transfer between sensor element
Viscoplastic constitutive relationships with dependence on thermomechanical history
Experimental evidence of thermomechanical history dependence in the cyclic hardening behavior of some common high-temperature structural alloys is presented with special emphasis on dynamic metallurgical changes. The inadequacy of formulating nonisothermal constitutive equations solely on the basis of isothermal testing is discussed. A representation of thermoviscoplasticity is proposed that qualitatively accounts for the observed hereditary behavior. This is achieved by formulating the scalar evolutionary equation in an established viscoplasticity theory to reflect thermomechanical path dependence. To assess the importance of accounting for thermomechanical history dependence in practical structural analyses, two qualitative models are specified: (1) formulated as if based entirely on isothermal information; (2) to reflect thermomechanical path dependence using the proposed thermoviscoplastic representation. Predictions of the two models are compared and the impact the calculated differences in deformation behavior may have on subsequent lifetime predictions is discussed
Polynomial Cointegration among Stationary Processes with Long Memory
n this paper we consider polynomial cointegrating relationships among
stationary processes with long range dependence. We express the regression
functions in terms of Hermite polynomials and we consider a form of spectral
regression around frequency zero. For these estimates, we establish consistency
by means of a more general result on continuously averaged estimates of the
spectral density matrix at frequency zeroComment: 25 pages, 7 figures. Submitted in August 200
Static solutions from the point of view of comparison geometry
We analyze (the harmonic map representation of) static solutions of the
Einstein Equations in dimension three from the point of view of comparison
geometry. We find simple monotonic quantities capturing sharply the influence
of the Lapse function on the focussing of geodesics. This allows, in
particular, a sharp estimation of the Laplacian of the distance function to a
given (hyper)-surface. We apply the technique to asymptotically flat solutions
with regular and connected horizons and, after a detailed analysis of the
distance function to the horizon, we recover the Penrose inequality and the
uniqueness of the Schwarzschild solution. The proof of this last result does
not require proving conformal flatness at any intermediate step.Comment: 41 page
A study of wing body blending for an advanced supersonic transport
Increases in supersonic cruise lift drag ratio were sought at Mach numbers 2.2 and 2.7 using wing body planform and thickness blending. Constrained twist and camber optimization was performed in the presence of nacelles. Wing and fuselage thickness distributions were optimized for either minimum volume wave drag or minimum total pressure wave drag. The zero leading edge suction lift drag ratios were determined for three wing planforms. The magnitude of the effect of leading edge suction on attainable lift drag ratio was defined on one planform and estimation of available leading edge suction was made
Epitaxial silicon growth for solar cells
Growth and fabrication procedures for the baseline solar cells are described along with measured cell parameters, and the results. Reproducibility of these results was established and the direction to be taken for higher efficiency is identified
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