Browsing Master's Theses by Title
Now showing items 10946-10965 of 14780
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The Rabi Yehuda Halevy: The Physical and Conceptual Space of a Sephardic Synagogue in Mexico CityThis thesis analyzes Rabi Yehuda Halevy synagogue, which Victor Babani designed and Francisco Canovas built from 1941 to 1942 in the Colonia Roma Sur of Mexico City. I focus on its formal characteristics, as well as its socio-historical context. I examine late-nineteenth century to mid-twentieth century life for Sephardic Jews in Mexico: their cause for immigration, experience in their new homeland, and relations with other Jewish groups and non-Jews in the city. I explore the use of style and iconography in the synagogue in relation to the history and prior employment of these architectural features. Defining "style" in the Rabi Yehuda Halevy demands an understanding of the employment of a particular formal language in the design of minority groups' architecture. The process of finding a style to portray national identity in Mexico was parallel to the Mexican Sephardim's use of architecture to articulate their own identity in the city.
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Race and public policy in Brazil: Immigration, Sao Paulo and the First RepublicThis paper investigates the absence of racial public policy in Brazil during the First Republic. Using secondary sources, this paper looks at economic competition and conflict between black and immigrant labor in the state of Sao Paulo and tests the applicability of the split labor market theory of ethnic antagonism--a theory used in explaining the development of ethnic conflict into racial public policy. Such conflict has been a primary factor in the development of racial public policies such as those found in the United States and South Africa. The political organization of black Brazilians and immigrant (primary Italian) groups is also analyzed to discover whether or not these groups would have been capable of translating their economic goals into race-based public policy. The thesis suggests that there was little competition in many areas, and that even where there was little competition, neither group had sufficient political capacity to successfully push for exclusionary public policies based on race.
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Radiation Dose Study in Nuclear Medicine Using GATEDose as a result of radiation exposure is the notion generally used to disclose the imparted energy in a volume of tissue to a potential biological effect. The basic unit defined by the international system of units (SI system) is the radiation absorbed dose, which is expressed as the mean imparted energy in a mass element of the tissue known as "gray" (Gy) or J/kg. The procedure for ascertaining the absorbed dose is complicated since it involves the radiation transport of numerous types of charged particles and coupled photon interactions. The most precise method is to perform a full 3D Monte Carlo simulation of the radiation transport. There are various Monte Carlo toolkits that have tool compartments for dose calculations and measurements. The dose studies in this thesis were performed using the GEANT4 Application for Emission Tomography (GATE) software (Janet al., 2011) GATE simulation toolkit has been used extensively in the medical imaging community, due to the fact that it uses the full capabilities of GEANT4. It also utilizes an easy to-learn GATE macro language, which is more accessible than learning the GEANT4/C++ programming language. This work combines GATE with digital phantoms generated using the NCAT (NURBS-based cardiac-torso phantom) toolkit (Segars et al., 2004) to allow efficient and effective estimation of 3D radiation dose maps. The GATE simulation tool has developed into a beneficial tool for Monte Carlo simulations involving both radiotherapy and imaging experiments. This work will present an overview of absorbed dose of common radionuclides used in nuclear medicine and serve as a guide to a user who is setting up a GATE simulation for a PET and SPECT study.
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Radiation effects on power MOSFETs under simulated space radiation conditionsApplication of power MOSFETs in spaceborne power converters was simulated by exposing devices to low-dose-rate ionizing radiation. Both radiation-hardened and nonhardened devices were tested with constant and switched gate biases during irradiation. In addition, some of the devices were under load. The threshold-voltage shifts were strongly bias dependent. The threshold-voltage shift of the nonhardened parts was approximately dose-rate independent, while the hardened parts exhibited significant dose-rate dependence. A pre-anneal dose-rate dependence was found for the interface-state buildup of the switched and positively biased devices, but the results for the switched devices were qualitatively different than those for the positively biased devices. The buildup of interface trapped charge was found to be the primary contributor to mobility degradation, which results in reduced drive capability and slower operation of the devices. These results indicate that new methods need to be utilized to accurately predict the performance of power MOSFETs in space environments.
