Engineering Science and Materials Commons^™

On A Taylor Weak Statement For Finite Element Computations In Gas Dynamics, Jin Whan Kim

Doctoral Dissertations

The Taylor Weak Statement has been developed as a potential unified approach for approximate computation of fluid flows. It is verified to contain a variety of numerical dissipative methods developed for advection problems by specific identification of its expansion parameters. Generalized Fourier modal analysis has been completed in one space dimension for both semi-and fully-discrete approximations, from which the flux limiter method is herein developed and evaluated for finite element computations. Its application to 1- and 2-dimensional scalar models is investigated for continuous and discontinuous initial value problems, and its use for the Euler equation system of gas dynamics in …

A Machining System For Turning Nonaxisymmetric Surfaces, Spivey Stevens Douglass

Doctoral Dissertations

Aspheric reflecting surfaces possessing extremely high surface finish and contour accuracy are often demanded by the optics industry. Such reflectors have also been required in high energy gas laser systems used to trigger thermonuclear reactions in experiments connected with advanced electric power generation.

Historically, production of optical pieces of the quality described required many repetitions of selective hand-lapping, polishing and measuring. In the past ten years production of these pieces has been enhanced by machining with diamond cutting tools on precision numerically controlled (NC) turning machines. These machines are capable of generating axisymmetric surfaces competitive in quality to those produced …

An Investigation Of The Thermal Conductivity, Electrical Resistivity, And Thermoelectric Power Of Thorium Nitride-Uranium Nitride Alloys, Samuel Cavin Weaver

Doctoral Dissertations

Thermal conductivity, electrical resistivity, and thermoelectric. power measurements were made on thorium nitride (ThN), (Th-2% U)N, and (Th-5% U)N; electrical resistivity and thermoelectric power measurements were made on uranium nitride (UN). Results from the experiments indicated that ThN behaves very nearly as a pure metal in its transport properties. Thermal conductivities, λ, were high, electrical resistivities, ρ, were low, and thermoelectric power, S, measurements were nearly zero. Uranium nitride, which antiferromagnetic below 50°K and has a lower thermal conductivity, had a much higher electrical resistivity and a large positive thermoelectric power.

The thermal conductivity of ThN is much higher than …