Analysis of factors affecting station capacitor bank switching transients

The problem presented here is a study using a computer program which predicts the transient response when energizing a station capacitor bank of a power system. The computer program gives the wave shape and magnitudes of switching surges obtained while energized capacitor banks at one location and showing the effect of switching a bank while adjacent banks are already energized. The over voltages are given in line-to-ground voltages on the line side of the capacitor banks as well as at lower voltage levels down to the customer 120 volts service voltages. The purposes are to obtain the optimum values of pre-insertion resistors, the effect of time differences of the pole closures of the three phases in a two-step switching of capacitor banks, and the effect of impedance between banks as an aid in determining the location of future capacitor banks in the station. The effect of distance between banks on the frequency of transients and on magnitude of maximum voltages is investigated --Abstract, page ii

Magmatic Evolution of the Eocene Volcanic Rocks of the Bijgerd Kuh E Kharchin Area, Uromieh-Dokhtar Zone, Iran

Composition and texture of the Middle and Late Eocene volcanic, volcaniclastic, and volcanic-sedimentary rocks in the Bijgerd-Kuh e Kharchin area, in the Uromieh-Dokhtar zone northwest of Saveh, Iran, suggest the complexity of the magmatic system that involved multiple eruptions from one or more sources. Hydrated volcanic fragments in hyaloclastic rocks, and the presence of a sequence of shallow and intermediate-depth marine microfossils, suggest that the Middle Eocene units were erupted in a marine basin. The bimodal volcanism of the Late Eocene is distinguished by the presence of four alternating sequences of hyaloclastite lava and ignimbrite. The REE patterns show spatial homogeneity and temporal heterogeneity in the composition of all the Late Eocene sequences, suggesting origination of magma from varying sources that erupted at different times. The trace element distributions of the hyaloclastites and ignimbrites are compatible with those evolved through fractional crystallization of the lower and upper continental crust, respectively

Spatio-Temporal Analyses of Cenozoic Normal Faulting, Graben Basin Sedimentation, and Volcanism around the Snake River Plain, SE Idaho and SW Montana

This dissertation analyzes the spatial distribution and kinematics of the Late Cenozoic Basin and Range (BR) and cross normal fault (CF) systems and their related graben basins around the Snake River Plain (SRP), and investigates the spatio-temporal patterns of lavas that were erupted by the migrating Yellowstone hotspot along the SRP, applying a diverse set of GIS-based spatial statistical techniques. The spatial distribution patterns of the normal fault systems, revealed by the Ripley\u27s K-function, display clustered patterns that correlate with a high linear density, maximum azimuthal variation, and high box-counting fractal dimensions of the fault traces. The extension direction for normal faulting is determined along the major axis of the fractal dimension anisotropy ellipse measured by the modified Cantor dust method and the minor axis of the autocorrelation anisotropy ellipse measured by Ordinary Kriging, and across the linear directional mean (LDM) of the fault traces. Trajectories of the LDMs for the cross faults around each caldera define asymmetric sub-parabolic patterns similar to the reported parabolic distribution of the epicenters, and indicate sub-elliptical extension about each caldera that may mark the shape of hotspot’s thermal doming that formed each generation of cross faults. The decrease in the spatial density of the CFs as a function of distance from the axis of the track of the hotspot (SRP) also suggests the role of the hotspot for the formation of the cross faults. The parallelism of the trend of the exposures of the graben filling Sixmile Creek Formation with the LDM of their bounding cross faults indicates that the grabens were filled during or after the CF event. The global and local Moran’s I analyses of Neogene lava in each caldera along the SRP reveal a higher spatial autocorrelation and clustering of rhyolitic lava than the coeval basaltic lava in the same caldera. The alignment of the major axis of the standard deviational ellipses of lavas with the trend of the eastern SRP, and the successive spatial overlap of older lavas by progressively younger mafic lava, indicate the migration of the centers of eruption as the hotspot moved to the northeast

Síntese e estudo das propriedades térmicas de materiais magnetocalóricos tricríticos

This work presents a novel and elaborate framework to evaluate promising materials for magnetocaloric application. In the first step, the molecular meanfield theory (Bean-Rodbell model) is applied to simulate various magnetic systems covering the first and second order transition. The magnetic systems of second order transition are analyzed to find the appropriate composition for a magnetic field change comparable to practical values (up to 2 Tesla). Moreover, the intrinsic hysteresis occurring in first order materials is estimated, under certain magnetic field change, and its impact on the materials’ cooling capacity is calculated. The most efficient candidate in terms of cooling capacity is detected via the comparison between materials of various transition behavior. A set of samples of La2/3(Ca1-xSrx)1/3MnO3 magnetocaloric family with transitions ranging from second to first order is produced and the data is fitted with the simulation tool to parameters such as spin value and the magnetovolume coupling parameter. Magnetic systems similar to experimental samples are simulated and the cooling capacity of the simulated system and experimental samples are compared to verify the theoretical model. The temperature dependence of the thermal conductivity of the La-Ca-Sr-Mn-O and Mn-Fe-P-Si systems are measured and show up to 50% change within the operating temperature ranges along with fully contrasting behaviour for the two families of magnetocaloric materials. It is also shown that the temperature dependence of thermal conductivity is coordinated with the order of the magnetic transition. By synthesizing La1-x(Ce, Pr, Nd)xFe11.6Si1.4 samples via a combination of induction melting and suction casting techniques, the substitution range is expanded up to x=0.4. The impact of La substitution on the magnetocaloric characteristics including magnetic entropy change, adiabatic temperature change, Tc and hysteresis is investigated. Finally, the phase transition order is studied using methods based on field dependence of magnetocaloric effect (including the Bean-Rodbell model).Este trabalho apresenta uma abordagem inovadora para a avaliação de materiais promissores para aplicações magnetocalóricas. Inicialmente, a teoria do campo médio molecular (modelo Bean-Rodbell) é aplicada para simular vários sistemas magnéticos que descrevem transições de primeira e de segunda ordem. Os sistemas magnéticos de transição de segunda ordem são analisados para encontrar a composição com performance otimizada para uma mudança de campo magnético comparável aos valores práticos (até 2 Tesla). Além disso, a histerese intrínseca que ocorre em materiais de primeira ordem é estimada, sob certas alterações de campo magnético, e o seu impacto na capacidade de arrefecimento dos materiais é calculado. O candidato mais eficiente em termos de capacidade de refrigeração é detectado através da comparação entre materiais com vários comportamentos diferentes na transição. Um conjunto de amostras da família magnetocalórica La2/3(Ca1-xSrx)1/3MnO3 com transições variando de segunda e primeira ordem foi produzido e os dados foram ajustados com a ferramenta de simulação e parâmetros como valor de spin e o parâmetro de acoplamento magneto-volume. Sistemas magnéticos semelhantes às amostras experimentais foram simulados e a capacidade de arrefecimento do sistema simulado e amostras experimentais foram comparadas para verificar o modelo teórico. A dependência da temperatura da condutividade térmica dos sistemas La-Ca-Sr-Mn-O e Mn-Fe- P-Si foi medida e mostra alterações de até 50% dentro das faixas de temperatura de operação, além de um comportamento totalmente contrastante para as duas famílias de materiais magnetocalóricos. Também é mostrado que a dependência na temperatura da condutividade térmica é coordenada com a ordem da transição magnética. Sintetizando a família de amostras de La1-x(Ce, Pr, Nd)xFe11.6Si1.4 por meio de uma combinação de técnicas de fusão por indução e fundição por sucção, a faixa de substituição é expandida até x = 0.4. O impacto da substituição de La nas características magnetocalóricas, incluindo alteração da entropia magnética, mudança de temperatura adiabática, Tc e histerese, é investigada. Finalmente, a ordem de transição de fase é estudada usando métodos baseados na dependência de campo do efeito magnetocalórico (incluindo o modelo Bean-Rodbell).Programa Doutoral em Ciência e Engenharia de Materiai

Parametric Study of Polymer-Nanoparticles-Assisted Injectivity Performance for Axisymmetric Two-Phase Flow in EOR Processes

Among a wide range of enhanced oil-recovery techniques, polymer flooding has been selected by petroleum industries due to the simplicity and lower cost of operational performances. The reason for this selection is due to the mobility-reduction of the water phase, facilitating the forward-movement of oil. The objective of this comprehensive study is to develop a mathematical model for simultaneous injection of polymer-assisted nanoparticles migration to calculate an oil-recovery factor. Then, a sensitivity analysis is provided to consider the significant influence of formation rheological characteristics as type curves. To achieve this, we concentrated on the driving mathematical equations for the recovery factor and compare each parameter significantly to nurture the differences explicitly. Consequently, due to the results of this extensive study, it is evident that a higher value of mobility ratio, higher polymer concentration and higher formation-damage coefficient leads to a higher recovery factor. The reason for this is that the external filter cake is being made in this period and the subsequent injection of polymer solution administered a higher sweep efficiency and higher recovery factor

Excitation of source electromagnetic waves at microwave frequencies using optical techniques

The coupling efficiencies for the excitation of surface electromagnetic waves (SEW} for both the prism and the grating techniques have been studied experimentally in the microwave frequency range. The grating experiments included studies of the SEW coupling efficiencies as functions of the frequency, the angle of incidence, the grating constant, the number of grating bars, and the position of the grating bar at which the maximum radiation field of the antenna was aimed. For the prism coupling technique, the coupling efficiency was studied as functions of the angle of incidence, the aiming point of the transmitting antenna on the prism base, and the height of the prism above the metal strip or the standard railroad rail. The coupling efficiency for the prism coupling technique was found to be about 60 percent, whereas for the grating technique, the coupling efficiency was found to be about 15 percent. The coupling efficiencies for either coupling technique were found to be different for metal overlaid with thin dielectric materials and uncoated metal surfaces --Abstract, pages 2-3

Spatio-Temporal Analyses of Cenozoic Normal Faulting, Graben Basin Sedimentation, and Volcanism around the Snake River Plain, SE Idaho and SW Montana

This dissertation analyzes the spatial distribution and kinematics of the Late Cenozoic Basin and Range (BR) and cross normal fault (CF) systems and their related graben basins around the Snake River Plain (SRP), and investigates the spatio-temporal patterns of lavas that were erupted by the migrating Yellowstone hotspot along the SRP, applying a diverse set of GIS-based spatial statistical techniques. The spatial distribution patterns of the normal fault systems, revealed by the Ripley\u27s K-function, display clustered patterns that correlate with a high linear density, maximum azimuthal variation, and high box-counting fractal dimensions of the fault traces. The extension direction for normal faulting is determined along the major axis of the fractal dimension anisotropy ellipse measured by the modified Cantor dust method and the minor axis of the autocorrelation anisotropy ellipse measured by Ordinary Kriging, and across the linear directional mean (LDM) of the fault traces. Trajectories of the LDMs for the cross faults around each caldera define asymmetric sub-parabolic patterns similar to the reported parabolic distribution of the epicenters, and indicate sub-elliptical extension about each caldera that may mark the shape of hotspot’s thermal doming that formed each generation of cross faults. The decrease in the spatial density of the CFs as a function of distance from the axis of the track of the hotspot (SRP) also suggests the role of the hotspot for the formation of the cross faults. The parallelism of the trend of the exposures of the graben filling Sixmile Creek Formation with the LDM of their bounding cross faults indicates that the grabens were filled during or after the CF event. The global and local Moran’s I analyses of Neogene lava in each caldera along the SRP reveal a higher spatial autocorrelation and clustering of rhyolitic lava than the coeval basaltic lava in the same caldera. The alignment of the major axis of the standard deviational ellipses of lavas with the trend of the eastern SRP, and the successive spatial overlap of older lavas by progressively younger mafic lava, indicate the migration of the centers of eruption as the hotspot moved to the northeast