Browsing by Subject "Kinetic theory of gases"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
Item An experimental and theoretical investigation of nonequilibrium behavior of electrons in gases(Texas Tech University, 1984-05) Young, Chris MorrowNot availableItem An investigation of non-equilibrium electron kinetics in nitrogen(Texas Tech University, 1983-12) Tzeng, YonhuaThe kinetic behavior of electrons immersed in a background gas or gas mixture under the action of an externally applied electric field with or without the influence of the space charge induced electric fields have been investigated. Novel Monte Carlo techniques have been developed and applied to study the evolution of the electrons self-consistently , that is, including the effects of the electric field generated by the space charge and the effects of boundaries. Statistical fluctuations of the macroscopic variables describing the evolution of the electron assembly have been studied. This is important when the total number of electrons is less than about 100. Ensemble averaged descriptions, kinetic in nature, have been used to study the development of an avalanche and the formation and propagation of a streamer. The results from this research program have provided key fundamental knowledge necessary for the explanation of the approach to equilibrium of an assembly of electrons, the effects of scattering processes on the electron velocity distribution, prebreakdown phenomena and manipulating the dielectric properties of gas mixtures used in insulating and switching applications.Item Analysis of adiabatic kinetic data(Texas Tech University, 1965-08) Carradine, William RadellThis investigation was concerned with the fitting of Hougen and Watson type catalytic reaction rate equations to adiabatic data. A particular equation corresponding to the case in which the surface reaction is the rate controlling step was chosen, and data were mathematically generated there from. Steepest descent methods were used to fit the equation (in the least-squares sense) to the data. It was found that the sum-of-squares response surface for this particular equation is quite rough. The steepest descent search for the correct set of parameters led to a number of sets depending on the starting point, A parameter perturbation search was proposed which aided the steepest descent: search. Even though error free data were used, it was found that this combined search procedure is not robust enough to accurately determine parameter values without considerable previous knowledge of their values. It can be used to obtain a data fir over a relatively wide range of experimental conditions such that the average error in the calculated rates is about fifty percent. The combined search was also applied to a set of data from the literature. The classical linearization technique used by the original experimenters provided a solution which resulted in an average error of thirty-five percent. From a starting point corresponding to the final linearized solution the combined search technique was used to reduce the average error to nineteen percent. When other starting points were used, it let to solutions such that the error was about the same as that obtained by the linearization procedure.Item The Boltzmann equation : sharp Povzner inequalities applied to regularity theory and Kaniel & Shinbrot techniques applied to inelastic existence(2008-08) Alonso, Ricardo Jose, 1972-; Martínez Gamba, Irene, 1957-This work consists of three chapters. In the first chapter, a brief overview is made on the history of the modern kinetic theory of elastic and dilute gases since the early stages of Maxwell and Boltzmann. In addition, I short exposition on the complexities of the theory of granular media is presented. This chapter has the objectives of contextualize the problems that will be studied in the remainder of the document and, somehow, to exhibit the mathematical complications that may arise in the inelastic gases (not present in the elastic theory of gases). The rest of the work presents two self-contained chapters on different topics in the study of the Boltzmann equation. Chapter 2 focuses in studying and extending the propagation of regularity properties of solutions for the elastic and homogeneous Boltzmann equation following the techniques introduced by A. Bobylev in 1997 and Bobylev, Gamba and Panferov in 2002. Meanwhile, chapter 3 studies the existence and uniqueness of the inelastic and inhomogeneous Cauchy problem of the Boltzmann equation for small initial data. A new set of global in time estimates, proved for the gain part of the inelastic collision operator, are used to implement the scheme introduced by Kaniel and Shinbrot in the late 70’s. This scheme, known as Kaniel and Shinbrot iteration, produces a rather simple and beautiful proof of existence and uniqueness of global solutions for the Boltzmann equation with small initial data.Item Closures of the Vlasov-Poisson system(2003) Jones, Christopher Scott; Morrison, Philip J.