The Experts below are selected from a list of 57 Experts worldwide ranked by ideXlab platform
Huijiang Zhao - One of the best experts on this subject based on the ideXlab platform.
-
one dimensional compressible heat conducting gas with temperature dependent Viscosity
Mathematical Models and Methods in Applied Sciences, 2016Co-Authors: Tao Wang, Huijiang ZhaoAbstract:We consider the one-dimensional compressible NaVier–Stokes system for a Viscous and heat-conducting ideal polytropic gas when the Viscosity μ and the heat conductiVity κ depend on the Specific Volume V and the temperature θ and are both proportional to h(V)θα for certain non-degenerate smooth function h. We proVe the existence and uniqueness of a global-in-time non-Vacuum solution to its Cauchy problem under certain assumptions on the parameter α and initial data, which imply that the initial data can be large if |α| is sufficiently small. Such a result appears to be the first global existence result for general adiabatic exponent and large initial data when the Viscosity coefficient depends on both the density and the temperature.
-
one dimensional compressible heat conducting gas with temperature dependent Viscosity
arXiv: Analysis of PDEs, 2015Co-Authors: Tao Wang, Huijiang ZhaoAbstract:We consider the one-dimensional compressible NaVier--Stokes system for a Viscous and heat-conducting ideal polytropic gas when the Viscosity $\mu$ and the heat conductiVity $\kappa$ depend on the Specific Volume $V$ and the temperature $\theta$ and are both proportional to $h(V)\theta^{\alpha}$ for certain non-degenerate smooth function $h$. We proVe the existence and uniqueness of a global-in-time non-Vacuum solution to its Cauchy problem under certain assumptions on the parameter $\alpha$ and initial data, which imply that the initial data can be large if $|\alpha|$ is sufficiently small. Our result appears to be the first global existence result for general adiabatic exponent and large initial data when the Viscosity coefficient depends on both the density and the temperature.
Tao Wang - One of the best experts on this subject based on the ideXlab platform.
-
one dimensional compressible heat conducting gas with temperature dependent Viscosity
Mathematical Models and Methods in Applied Sciences, 2016Co-Authors: Tao Wang, Huijiang ZhaoAbstract:We consider the one-dimensional compressible NaVier–Stokes system for a Viscous and heat-conducting ideal polytropic gas when the Viscosity μ and the heat conductiVity κ depend on the Specific Volume V and the temperature θ and are both proportional to h(V)θα for certain non-degenerate smooth function h. We proVe the existence and uniqueness of a global-in-time non-Vacuum solution to its Cauchy problem under certain assumptions on the parameter α and initial data, which imply that the initial data can be large if |α| is sufficiently small. Such a result appears to be the first global existence result for general adiabatic exponent and large initial data when the Viscosity coefficient depends on both the density and the temperature.
-
one dimensional compressible heat conducting gas with temperature dependent Viscosity
arXiv: Analysis of PDEs, 2015Co-Authors: Tao Wang, Huijiang ZhaoAbstract:We consider the one-dimensional compressible NaVier--Stokes system for a Viscous and heat-conducting ideal polytropic gas when the Viscosity $\mu$ and the heat conductiVity $\kappa$ depend on the Specific Volume $V$ and the temperature $\theta$ and are both proportional to $h(V)\theta^{\alpha}$ for certain non-degenerate smooth function $h$. We proVe the existence and uniqueness of a global-in-time non-Vacuum solution to its Cauchy problem under certain assumptions on the parameter $\alpha$ and initial data, which imply that the initial data can be large if $|\alpha|$ is sufficiently small. Our result appears to be the first global existence result for general adiabatic exponent and large initial data when the Viscosity coefficient depends on both the density and the temperature.
Alex C Hoffmann - One of the best experts on this subject based on the ideXlab platform.
-
structural ratio for predicting the Voidage of binary particle mixtures
Aiche Journal, 1998Co-Authors: Hendrikus Finkers, Alex C HoffmannAbstract:Knowledge of the Voidage of mixtures of particles is important for predicting the packing properties of particulate products and the rheology of concentrated particle suspensions and fluidized particles, which again determines handling properties. Powders containing more than one type of particle are used extensiVely in industry, for example, for the coatings, food, pharmaceutical, cosmetics, and cement industries. In this article an improVed method for predicting the Voidage of binary particle mixtures, applicable to both spherical and nonspherical particles will be presented. Westman (1936) deVeloped an empirical model for predicting the Voidage of binary particle mixtures. He deVised a simple conical expression containing one fit parameter G (the relation is giVen below). Various workers haVe since giVen empirical relations for G as a function of the ratio of particle diameters r = dp s/dp,l where the subscripts s and I refer to the small and large particle fractions, respectiVely. Relations for G(r) fitted to data for spherical particles do not work for nonspherical ones. Yu et al. (1993) suggested using a packing equiValent particle diameter for nonspherical particles, and showed that the relation giVen G(r) for spherical particles could then also he used for nonspherical ones. A number of other workers haVe addressed the problem of packing of binary mixtures. but none appear to carry as much promise as the Westman equation for modeling both spherical and nonspherical particles. The Westman equation accounts correctly for both of thc extremes r = 1 and r + 0, which can both be calculated analytically as mentioned below. Westman’s (1936) equation for the total bed Volume occupied by unit Volume of solid material (called the Specific Volume) V (equal to 1x1 - E), where E is the fractional Voidage of the particle bed), is in the notation of Yu et al. (1993)
Ashraf M Alam - One of the best experts on this subject based on the ideXlab platform.
-
free Volume glass transition and degree of branching in ethylene α olefin copolymers positron lifetime differential scanning calorimetry wide angle x ray scattering and density studies
Macromolecular Chemistry and Physics, 2006Co-Authors: D Bamford, G Dlubek, T Lupke, Duncan Kilburn, J Stejny, Tammo J Menke, Ashraf M AlamAbstract:Positron annihilation lifetime spectroscopy, differential scanning calorimetry, wide-angle X-ray scattering, and density measurements were used to systematically study the Variation of the glass transition temperature Tg and the mean size ν h of holes (local free Volumes) in n-alkyl branched polyethylenes. The samples were commercial ethylene-rich copolymers with 1-propene, 1-butene, and 1-octene comonomers. From the total Specific Volume V and the crystallinity X c the Specific Volume of the amorphous phase Va was estimated and used to calculate the Specific hole-free Volume V f . It was found that T g and X c decrease and V, V a , V f , and ν h increase with increasing weight fraction of comonomers. Both the real crystalline and amorphous Specific Volumes decrease with increasing crystallinity X c . For not too high contents of comonomers, Tg decreases and ν h increases linearly with the number and with the length of n-alkyl branches. This behaVior was attributed to an increased segmental mobility caused by branching. Both Tg and ν h follow linear master curVes as a function of the degree of branching if this is defined as the fractional number of carbon atoms in the side chains compared with the total number of carbon atoms. A method for estimating T g from ν h measured at room temperature is shown. The number density of holes N h shows a slight Variation from 0.6 to 0.8 (±0.1) nm -3 with increasing branching.
Hendrikus Finkers - One of the best experts on this subject based on the ideXlab platform.
-
structural ratio for predicting the Voidage of binary particle mixtures
Aiche Journal, 1998Co-Authors: Hendrikus Finkers, Alex C HoffmannAbstract:Knowledge of the Voidage of mixtures of particles is important for predicting the packing properties of particulate products and the rheology of concentrated particle suspensions and fluidized particles, which again determines handling properties. Powders containing more than one type of particle are used extensiVely in industry, for example, for the coatings, food, pharmaceutical, cosmetics, and cement industries. In this article an improVed method for predicting the Voidage of binary particle mixtures, applicable to both spherical and nonspherical particles will be presented. Westman (1936) deVeloped an empirical model for predicting the Voidage of binary particle mixtures. He deVised a simple conical expression containing one fit parameter G (the relation is giVen below). Various workers haVe since giVen empirical relations for G as a function of the ratio of particle diameters r = dp s/dp,l where the subscripts s and I refer to the small and large particle fractions, respectiVely. Relations for G(r) fitted to data for spherical particles do not work for nonspherical ones. Yu et al. (1993) suggested using a packing equiValent particle diameter for nonspherical particles, and showed that the relation giVen G(r) for spherical particles could then also he used for nonspherical ones. A number of other workers haVe addressed the problem of packing of binary mixtures. but none appear to carry as much promise as the Westman equation for modeling both spherical and nonspherical particles. The Westman equation accounts correctly for both of thc extremes r = 1 and r + 0, which can both be calculated analytically as mentioned below. Westman’s (1936) equation for the total bed Volume occupied by unit Volume of solid material (called the Specific Volume) V (equal to 1x1 - E), where E is the fractional Voidage of the particle bed), is in the notation of Yu et al. (1993)