This paper is concerned with scaling limits in kinetic semiconductor models. For the classical Vlasov-Poisson-Fokker-Planck equation and its quantum mechanical counterpart, the Wigner-Poisson-Fokker-Planck equation, three distinguished scaling regimes are presented. Using Hilbert and Chapman-Enskog expansions, we derive two drift-diiusion type approximations. The test case of a n + ?n?n + diode...

This paper is concerned with scaling limits in kinetic semiconductor models. For the classical Vlasov-Poisson-Fokker-Planck equation and its quantum mechanical counterpart, the Wigner-Poisson-Fokker-Planck equation, three distinguished scaling regimes are presented. Using Hilbert and Chapman-Enskog expansions, we derive two drift-diffusion type approximations. The test case of a n+−n−n+ diode r...

This work deals with a noncollisional kinetic model for non-neutral plasmas in a Penning trap. Using the spatial coordinates r, theta, z and the axial velocity v(z) as phase-space variables, a kinetic model is developed starting from the kinetic equation for the distribution function f(r,theta,z,v(z),t). In order to reduce the complexity of the model, the kinetic equations are integrated along ...

Enzyme hydrolysis kinetic model of inulin by inulinase from Kluyveromyces lactis was established. The corresponding Michaelis-Menten equation model constants were found to be related to temperature through the Arrhenius model. The kinetic model was validated by experimental data and also be utilized to predict the hydrolysis reaction rates of the inulin for substrate concentrations ranging betw...

thermal cracking of a heavy liquid hydrocarbon was performed in a laboratory scale tubular reactor. central composite design (ccd), was used as an experimental design method. the design variables were coil outlet temperature (cot), feed flow and rate steam ratio. maximum yield of ethylene was 30.37 wt% at cot, residence time and steam ratio of 869oc, 0.208 s and 1.22 g/g, respectively. maximum ...

Coherent transport in mesoscopic devices is well described by the Schrödinger equation supplemented by open boundary conditions. When electronic devices are operated at room temperature, however, a realistic transport model needs to include carrier scattering. In this work, the kinetic equation for the Wigner function is employed as a model for dissipative quantum transport. Carrier scattering ...

The olefins polymerization process in a slurry reactor is discussed. The reaction rate dynamics was analyzed and the contributions of feed flow, gas-liquid mass transfer, polymerization reaction, and catalyst deactivation were estimated. The propylene solubility in a solvent mixture “heptane” was calculated using Soave-Redlich-Kwong equation of state. These data were then approximated by Henry-...

We consider several systems of nonlinear hyperbolic conservation laws describing the dynamics of nonlinear waves in presence of phase transition phenomena. These models admit undercompressive shock waves which are not uniquely determined by a standard entropy criterion but must be characterized by a kinetic relation. Building on earlier work by LeFloch and collaborators, we investigate the nume...

We study a kinetic model for chemotaxis introduced by Othmer, Dunbar, and Alt [22], which was motivated by earlier results of Alt, presented in [1], [2]. In two papers by Chalub, Markowich, Perthame and Schmeiser, it was rigorously shown that, in three dimensions, this kinetic model leads to the classical KellerSegel model as its drift-diffusion limit when the equation of the chemo-attractant i...