Comparative Assessment of Adaptive-Stencil Finite Difference Schemes for Hyperbolic Equations with Jump Discontinuities

High-fidelity numerical solution of hyperbolic differential equations for functions with jump discontinuities presents a particular challenge. In general, fixed-stencil high-order numerical methods are unstable at discontinuities, resulting in exponential temporal growth of dispersive errors (Gibbs phenomena). Schemes utilizing adaptive stencils have shown to be effective in simultaneously providing high-order accuracy and long-time stability. In this Thesis, the elementary formulation of adaptive-stenciling is described in the finite difference context. Basic formulations are provided for three adaptive-stenciling methods: essentially non-oscillatory (ENO), weighted essentially non-oscillatory (WENO), and energy-stable weighted essentially non-oscillatory (ESWENO) schemes. Examples are presented to display some of the relevant properties of these schemes in solving one-dimensional and two-dimensional linear and nonlinear hyperbolic differential equations with discontinuities

Effective Techniques of Supervision for Instruction in Vocational Agriculture

In the preliminary statements of the introduction, an attempt was made to establish the importance of farming as an occupation and to justify research in all of its many areas. Since the passage of the Smith-Hughes act in 1917, teachers of Vocational Agriculture have employed a variety of techniques in developing and supervising farming programs with all-day students on the home farm. The study has been conducted in order to isolate the techniques contributing most to the success of farming programs. The use of some of these practices which are rated high, in this study, should result in teachers of vocational agriculture doing a more effective job of supervising the farming programs of their all-day students. This study is primarily concerned with the effective techniques for supervision of farming programs of all-day boys on the home farm. This study deals with information compiled from data supplied by a representative group of vocational agriculture teachers in Area I, Area II, and Area III. In making this study, the writer does not wish to point out the weaknesses of any particular program or teacher, but rather to make possible an overview of the factors which have in the past contributed to the development of supervised farming programs. No attempt was made to determine the causes of the conditions found

A Summary of the Facts and a Restatement of the Theory of Sound Localization

Experimentation has repeatedly demonstrated that phase, time and intensity, as physical variants, function in much the same manner in determining the directional localization of sound. Their effects are alike; the relationship of the angular displacement to the differences in the stimuli in each case is approximately the same; each factor has its optimal effectiveness; the very slight differences in the stimuli in each case are not perceived as differences in phase, time and intensity as such; and each factor may modify the effectiveness of the others. But, in the complex conditions of ordinary hearing, does either of these factors predominate in determining the directional localization, or are all of these factors reducible to some common factor, or do they each and all contribute to a pattern of effects that results in directional perception

Alien Registration- Wright, Otis C. (Fort Fairfield, Aroostook County)

https://digitalmaine.com/alien_docs/35903/thumbnail.jp

High-Fidelity Simulation of Compressible Flows for Hypersonic Propulsion Applications

In the first part of this dissertation, the scalar filtered mass density function (SFMDF) methodology is implemented into the computer code US3D. The SFMDF is a subgrid scale closure and is simulated via a Lagrangian Monte Carlo solver. US3D is an Eulerian finite volume code and has proven very effective for compressible flow simulations. The resulting SFMDF-US3D code is employed for large eddy simulation (LES) of compressible turbulent flows on unstructured meshes. Simulations are conducted of subsonic and supersonic flows. The consistency and accuracy of the simulated results are assessed along with appraisal of the overall performance of the methodology. In the second part of this dissertation, a new methodology is developed for accurate capturing of discontinuities in multi-block finite difference simulations of hyperbolic partial differential equations. The fourth-order energy-stable weighted essentially non-oscillatory (ESWENO) scheme on closed domains is combined with simultaneous approximation term (SAT) weak interface and boundary conditions. The capability of the methodology is demonstrated for accurate simulations in the presence of significant and abrupt changes in grid resolution between neighboring subdomains. Results are presented for the solutions of linear scalar hyperbolic wave equations and the Euler equations in one and two dimensions. Strong discontinuities are passed across subdomain interfaces without significant distortions. It is demonstrated that the methodology provides stable and accurate solutions even when large differences in the grid-spacing exist, whereas strong imposition of the interface conditions causes noticeable oscillations

The Phase-Theory as a Time Theory in Sound Localization

In a preliminary study of the phenomena of localization by the method of temporal difference of arrival of sound at the two ears, we find results which so nearly coincide with results obtained by Stewart (1) and by Halverson (3) who studied the problem by means of continuous sounds of varying phase relations at the ears, that we feel justified in presenting here the phase-theory as a time-theory in sound localization

United States foreign policy with the Union of Soviet Socialist Republics, 1945-1959

This thesis considers the changes in United States relations with the Soviet Union after World War II. In discussing the major events which shaped the changes in policy, I have not addressed the details of the events themselves, since each in itself is worthy of a complete volume. Instead, I have limited by discussion to the broad indicators of diplomatic policy changes which resulted from the events

Étude de la biodégradation de l'acide déhydroabiétique par Bacillus psychrophilus

La rivière du Saguenay (Québec, Canada) traverse une région fortement industrialisée (v.g. alumineries, papeteries) et reçoit d'importantes quantités d'eaux usées. Les teneurs en matière organique dissoute et en fibre de cellulose en suspension provenant de 4 papeteries locales sont relativement élevées dans les eaux de la Rivière et elles sont évaluéesà 29 000 tonnes par année. En plus des eaux usées industrielles, le Saguenay reçoit de grandes quantités d'eaux d'égouts domestiques, ce qui maintient une flore bactérienne relativement abondante et diversifiée dans ses eaux de surface. Parmi la matière organique provenant des papeteries, les acides résiniques abiétique et déhydroabiétique sont très toxiques pour les organismes aquatiques. Cependant, nous avons montré qu'en utilisant une population endogène de Bacillus psychrophilus, il était possible de biodégrader l'acide déhydroabiétique (ADA), un acide résinique non chloré. Nous avons constaté qu'après 72 heures de culture, la population bactérienne oxyde plus de 92 % de l'ADA et après 96 heures, la biodégradation est compléte. La cinétique de la biodégradation de l'ADA par B. psychrophilus a été étudiée en mesurant les fluctuations des teneurs en ATP et par chromatographie en phase gazeuse. Nous pensons que cette souche bactérienne peut jouer un rôle important dans la dépollution des eaux usées des papeteries du Saguenay.The Saguenay River (Quebec, Canada) is situated in an industrialized area (aluminium smelters, papers mills) and receives a great amount of industrial wastewaters. Concentrations of dissolved organic matter and suspended cellulose fibers from the 4 local paper mills are relatively high in the waters of the Saguenay River and are evaluated at 29 000 tons per year. Moreover, the Saguenay River receives urban wastewaters and the bacterial populations in the surface waters are abundant and diversified. Among the organic matter from the paper mills, the abietic and dehydroabietic resin acids are very toxic for aquatic organisms. Yet, we found that, with endogenous populations of Bacillus psychrophilus in the decantation-basin, it was possible to oxidize the dehydroabietic acid (DHA), a non chlorinated resinic acid. It was found that after 72 hours, more than 92 % of this pollutant was oxidized. After a period of 96 hours, biodegradation was complete. The kinetics of this reaction were studied by measuring the fluctuations of the rates of ATP and by gas chromatography. We think that this bacterial species is thus probably an important microorganism controlling the toxicity of the wastewaters from the paper mills of the Saguenay

Effective Integration of Ultra-Elliptic Solutions of the Focusing Nonlinear Schrödinger Equation

An effective integration method based on the classical solution of the Jacobi inversion problem, using Kleinian ultra-elliptic functions and Riemann theta functions, is presented for the quasi-periodic two-phase solutions of the focusing cubic nonlinear Schrödinger equation. Each two-phase solution with real quasi-periods forms a two-real-dimensional torus, modulo a circle of complex-phase factors, expressed as a ratio of theta functions associated with the Riemann surface of the invariant spectral curve. The initial conditions of the Dirichlet eigenvalues satisfy reality conditions which are explicitly parametrized by two physically-meaningful real variables: the squared modulus and a scalar multiple of the wavenumber. Simple new formulas for the maximum modulus and the minimum modulus are obtained in terms of the imaginary parts of the branch points of the Riemann surface