The Experts below are selected from a list of 68217 Experts worldwide ranked by ideXlab platform
J W Rose - One of the best experts on this subject based on the ideXlab platform.
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an Approximate Equation for the vapour side heat transfer coefficient for condensation on low finned tubes
International Journal of Heat and Mass Transfer, 1994Co-Authors: J W RoseAbstract:Abstract Simplifying approximations, together with dimensional analysis, have been used to obtain a formula for the relation between the heat flux and vapour-side temperature difference for condensation on low, integral-finned tubes. The final result involves two unknown (disposable) constants which have been determined from heat-transfer data. The resulting Equation is found to be in satisfactory agreement with experimental data from 11 investigations with various condensing fluids and a range of fin and tube geometries.
F. Zamponi - One of the best experts on this subject based on the ideXlab platform.
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Amorphous packings of hard spheres in large space dimension
Journal of Statistical Mechanics: Theory and Experiment, 2006Co-Authors: G. Parisi, F. ZamponiAbstract:In a recent paper (cond-mat/0506445) we derived an expression for the replicated free energy of a liquid of hard spheres based on the HNC free energy functional. An Approximate Equation of state for the glass and an estimate of the random close packing density were obtained in d=3. Here we show that the HNC approximation is not needed: the same expression can be obtained from the full diagrammatic expansion of the replicated free energy. Then, we consider the asymptotics of this expression when the space dimension d is very large. In this limit, the entropy of the hard sphere liquid has been computed exactly. Using this solution, we derive asymptotic expressions for the glass transition density and for the random close packing density for hard spheres in large space dimension.
G. Parisi - One of the best experts on this subject based on the ideXlab platform.
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Amorphous packings of hard spheres in large space dimension
Journal of Statistical Mechanics: Theory and Experiment, 2006Co-Authors: G. Parisi, F. ZamponiAbstract:In a recent paper (cond-mat/0506445) we derived an expression for the replicated free energy of a liquid of hard spheres based on the HNC free energy functional. An Approximate Equation of state for the glass and an estimate of the random close packing density were obtained in d=3. Here we show that the HNC approximation is not needed: the same expression can be obtained from the full diagrammatic expansion of the replicated free energy. Then, we consider the asymptotics of this expression when the space dimension d is very large. In this limit, the entropy of the hard sphere liquid has been computed exactly. Using this solution, we derive asymptotic expressions for the glass transition density and for the random close packing density for hard spheres in large space dimension.
S H Mohsenizonoozi - One of the best experts on this subject based on the ideXlab platform.
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a novel technique for estimation and control of stator flux of a salient pole pmsm in dtc method based on mtpf
IEEE Transactions on Industrial Electronics, 2003Co-Authors: Jawad Faiz, S H MohsenizonooziAbstract:A permanent-magnet synchronous machine (PMSM) can be controlled using the direct torque control (DTC) technique in three different ways, i.e., by controlling flux, reactive torque and rotor d-axis current. Frequently, the DTC technique controls the speed of the motor by controlling stator flux with the aim of obtaining an optimal torque. A varying flux, proportional to the torque, may be used instead of a fixed flux, resulting in a maximum torque per ampere or maximum torque per flux (MTPF). In this paper, a reference-flux-generating method is followed to achieve the MTPF. An Approximate Equation is then derived using numerical techniques in order to obtain the reference flux from the torque. This Equation is then applied to the DTC control system in order to obtain the reference flux. The control scheme has been verified by simulation and tests on a salient-pole permanent-magnet synchronous motor.
Hu Ya-yuan - One of the best experts on this subject based on the ideXlab platform.
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STUDY ON RELATIONSHIP BETWEEN ‘PRESENT Approximate Equation’ OF ENDOCHRONIC THEORY AND THE INCREMENT PLASTIC THEORY
Engineering mechanics, 2009Co-Authors: Hu Ya-yuanAbstract:The definition of a plastic time is presented and the intrinsic time suggested by Valanis K C is that of a specific case. Through analyzing the fundamental behavior of ‘present Approximate Equation’ of an integral endochronic model in terms of plastic time, the author reveals the necessary condition that yield surface and plastic potential exist in the ‘present Approximate Equation’. If the ‘present Approximate Equation’ has yield surface and plastic potential, the plastic factor of the ‘present Approximate Equation’ is equal to the product of the plastic time and Pfaffy’s integral denominator. When Pfaffy’s integral denominator is a positive constant, the plastic factor is equal to the plastic time. The endochronic model of dry sand with small strain is derived from the classical increment plastic theory in which the plastic time is used as the plastic factor. This model can well describe the dilatancy of sand and simulate the stress-strain response of dry sand due to cyclic loadings.
