Thesis (Ph.D.)--University of Iowa, 2006. / Supervisors: Larry J. Weber, George Constantinescu. Includes vita. Includes bibliographical references (leaves 220-222).

Thesis (Ph. D.)--Joint Program in Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Biology; and the Woods Hole Oceanographic Institution), 2005. / Includes bibliographical references.

Thesis (M.Oc.E)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 83-86). Also available on the World Wide Web.

Thesis (M.C.E.)--University of Delaware, 2009. / Principal faculty advisors: Jamie H. MacMahan and James T. Kirby, Dept. of Civil & Environmental Engineering. Includes bibliographical references.

Thesis (Ph. D.)--University of Hawaii at Manoa, 2003. / Includes bibliographical references (leaves 206-209).

Orientador: José Carlos Rossi / Banca: Antonio Carlos Delaiba / Banca: Carlos Alberto Canesin / Resumo: Este trabalho tem por objetivo a proposição de um estudo de caso realizado em uma planta industrial, cuja linha de produção se concentra na área da metalurgia. O principal enfoque foi direcionado na avaliação e nos efeitos causados pelas correntes distorcidas, geradas por cargas não lineares, nos barramentos e alimentadores da industria. Com o objetivo de avaliar o impacto das cargas elétricas, com características não lineares, as instalada e a serem instaladas no sistema elétrico da industria. Foi realizada também uma avaliação geral da planta da indústria através da análise das faturas de energia elétrica buscando identificar nos principais indicadores, os desvios no sistema elétrico da planta. Entre estes, podemos destacar a demanda, o consumo, os reativos excedentes e outros. Todos os procedimentos desenvolvidos neste trabalho foram direcionados no sentido de se usar racionalmente a energia elétrica e controlar o seu desperdício. / Abstract: This work aims to study a case carried out in an industrial plant, whose production line is concentrated on the metallurgy field. The main objective was addressed in the evaluation and in the effects caused by the distortion of the currents, due to nonlinear loads connected at the industry busbar and feeders. With the objective of evaluating the impact of the electric loads, with non- linear characteristics, or installed in the industry electric system. It was also accomplished a general evaluation of the industry plant by analyzing the electric power invoices looking for identifying, in the main quality power indicators, the deviations in the electric plant system. Among these, we can mention the demand, the consumption, the exceeding reactives and others. All the procedures developed in this work were addressed aiming to use the electric power rationally and to control its waste. / Mestre

A series resonant L-C circuit in which either the inductor or the capacitor is nonlinear and which is excited by a sinusoidal voltage of a fixed frequency may have two steady-state responses. One of these responses is characterized by a high amplitude oscillation; the other by a low one. If the amplitude or frequency of the driving signal is varied slowly, the response may suddenly change or "jump" to the other state. As a result, this phenomenon has been called jump resonance, or ferroresonance. Because the high and low resonant states could be considered as a 0 and 1 basis for digital logic operations, it was the purpose of this work to study the phenomenon and to investigate the possibility of using it in the design of digital logic elements. Equations which exhibit the necessary features were studied on an analogue computer. The results of the study were used as design criteria for the construction of an actual circuit and also as a basis for an approximate analytical study. The analytical study uses the Ritz method to find useful features of the responses. The results of previous users of this method have been extended to include equations with both second derivative coupling and non-symmetrical non-linearities. Based on the above studies, a prototype circuit was designed which has some of the basic properties of conventional flip-flop circuits. One of the main features of this circuit is that it is almost entirely made of reactive components and as a result has very low power consumption. The operation of the circuit is used to verify the validity of the approximations made in both the analogue simulation and the analytical study. The results obtained from the analogue study, the Ritz analysis, and the prototype circuit compare favorably with each other. Some suggestions for future work are given. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate

Geomagnetic induction techniques have been used to study the structure of the crust and upper mantle in western Canada. Geomagnetic depth-sounding (GDS) has been used primarily for mapping, and magnetotellurics (MT) for quantitative interpretation. Self-consistent models of electrical conductivity structure have been derived from the combined MT/GDS data. The conductivity structure models have been considered in conjunction with other relevant geophysical information: heat-flow, seismology and aeromagnetic surveys. No definite petrological models can be derived because of the order-of-magnitude uncertainties in the relations between electrical conductivity, temperature and composition. However, if we exclude geochemically improbable solutions, the following two distinct results can be extracted: a) In southwestern Canada (boundaries not clearly defined, but at least as far east as Lethbridge), the uppermost mantle is moderately conducting (resistivity 30-50 ohm-meters). This indicates a temperature of at least 750°C at depth 35 km., and provides independent confirmation (without assumptions of crustal structure) of the heat-flow derived estimates of Roy et al (1968b). b) In a sharply delineated region starting from about 0-30 km west of the Rocky Mountain Trench, the lower crust (from a depth of about 10-15 km) is conductive. The most likely interpretation is a hydrated lower crust, as proposed by Hyndman and Hyndman, 1968. Hydration alone is sufficient to explain the observed conductivities, i.e. higher temperatures are not necessarily required for this model. However, given the information from (a) above, some partial melting of hydrated granitic materials should occur in this zone; this is in good agreement with the geological evidence of granitic intrusives in this region. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

The present investigation considers the hydrodynamic forces acting on a slender structure subjected to a combined wave and current flow regime. The experimental aspect of the study measured the in-line peak-to-peak forces on a vertical cylinder mounted in a wave-current flume. Although there were some inconsistencies in the data, the general trend indicated a substantial increase in the force with a positive underlying current and a less pronounced increase for a negative current. A numerical analysis of the problem evaluated Morison's equation using the current-invariant force transfer coefficients and flow kinematics obtained through Stokes Fifth Order Wave Theory. The results of this analysis revealed a trend qualitatively similar to that found experimentally. The important distinction between the results obtained through the experimental investigation and those obtained numerically was the consistent over-prediction observed in the numerical analysis. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

Thesis (Ph. D)--Massachusetts Institute of Technology, Dept. of Meteorology, 1970. / Vita. / Bibliography: leaves 150-153. / by Henry T. Perkins. / Ph.D