Through the Zohar, the major medieval kabbalistic work, the human body is used in order to symbolise the divine structure. Present throughout are also dire warnings against the dangers of the flesh – a sense of anxiety often surrounds matters of the body. This study examines how the central notion of the body as created in God’s image relates to the negative zoharic characterizations of the body and further, how notions of gender and Jewish religious affiliation are reflected in the zoharic views of the body. The results show that characterizations of the body can work to reinforce boundaries and define the own group. The female body is valued differently than the male, the Jewish differently than the non-Jewish body. The idealized human body belongs to the circumcised Jewish male who adheres to proper religious behaviour. The aim of this thesis is to enrich our understanding of the human body as depicted in the major kabbalistic tradition of the Zohar.

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Approved for public release; distribution in unlimited. / Silicon Blocked Impurity Band (BIB) detectors are highly efficient, radiation-hardened photodetectors that operate in the range of 5-40 æm. To further extend BIB coverage to 40-350 æm, Ge and GaAs BIB detectors are under development; however, these new detectors face fabrication issues that have delayed their introduction. This thesis will describe the use of a numerical model to examine alternate operating modes for GaAs BIB detectors in order to bypass current fabrication issues. The numerical simulations provide an understanding of the fundamental physics that governs detector transport. The proposed alternatives to standard operation are created by reversing the detector's bias and varying the blocking layer thickness. Modeling indicates that reversing the bias on these detectors provides a larger signal current than standard configurations, while preserving the principal benefits gained from a multilayered device. At the same time, the alternate bias configuration allows for the use of thicker blocking layers, while preserving overall detector responsivity and reducing shot noise. This proposed new model of operation should allow for the relaxation of fabrication constraints without sacrificing the inherent benefits associated with BIB detectors. These devices are of potential interest for missile defense and terahertz surveillance applications. / Lieutenant Commander, United States Navy

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No description available.

Call number: LD2668 .T4 1985 K53 / Master of Science

The illegal drug ecstasy, chemically known as 3,4-methylenedioxymethamphetamine (MDMA), sometimes contains additional chemicals which can pose health risks to users. This thesis examines strategies that recreational ecstasy users in Victoria, British Columbia utilize to determine the purity of their ecstasy. It also examines why they use these strategies and if they are concerned about impure ecstasy affecting their health because this information can help explain the use of these strategies. I performed a quantitative analysis of data collected by the Centre for Addictions Research of BC’s survey, the Canadian Recreational Drug Use Survey, to determine the strategies participants utilized to minimize potential harms caused by ecstasy use. This analysis revealed that 73.9% of survey participants discussed purity of ecstasy with friends, 33.3% checked drug information websites, 17.4% used an ecstasy testing kit, 2.9% asked harm reduction services for advice, and 0% owned a testing kit. In addition, the data revealed that the participants were more likely to take ecstasy from a friend than a stranger. Next, I developed an interview guide based on these findings and I interviewed 10 female recreational ecstasy users. I chose to interview women only because recreational drug use by women is underrepresented in the drug literature. The most common strategy the women utilized to determine ecstasy purity was to discuss ecstasy with friends. They preferred this strategy because it was a convenient, practical strategy. Also, they perceived their friends to be a trusted source of ecstasy and ecstasy information. Half the women analyzed how they felt after ingesting ecstasy to determine its purity because they believed different chemicals caused different effects. Others assessed the physical characteristics of their ecstasy to try to determine purity because they believed these characteristics could reveal its chemical contents. One participant used an ecstasy testing kit, but the rest cited multiple barriers to their use. Some women also had negative attitudes towards testing kits and felt no social pressure to use them. I asked the participants about their use of ecstasy testing laboratories, but none used this service because they did not know it existed. Overall, none of the women seemed concerned about ecstasy impurity harms. This could be due to four factors. First, their ecstasy use patterns made them feel safe from harms related to ecstasy use. Second, recreational ecstasy use was “normal” amongst young adults in Victoria who attend parties, raves, or clubs. Third, they primarily obtained ecstasy and ecstasy information from trusted friends. Fourth, they had never suffered significant harm caused by ecstasy impurity, even though all of the women believed they had ingested impure ecstasy. / Graduate

Dans le cadre du développement des réacteurs nucléaires de 4ème génération et plus particulièrement du réacteur à neutrons rapides refroidi au sodium (SFR), le CO2 supercritique, dans un cycle de Brayton, a été identifié comme fluide potentiel en remplacement de la vapeur d'eau dans le cycle de conversion de l'énergie. Les aciers ferrito-martensitiques contenant 9 à 12 % en poids de Cr sont de bons candidats pour la réalisation d'échangeurs thermiques car ils présentent de bonnes propriétés mécaniques jusqu'à une température de 600°C, une forte conductivité thermique, un faible coefficient d'expansion thermique ainsi qu'un coût plus faible que celui des aciers austénitiques. Cependant, il a été montré que ces aciers forment une couche d’oxyde à croissance rapide et carburent fortement dans les conditions du circuit de conversion d'énergie (550°C, 250 bar).Cette étude a pour objectif d’étudier l’influence de différents paramètres (les impuretés présentes dans le CO2, les vitesses de rampe thermique ainsi que l’état de surface) sur le mécanisme d’oxydation d’un acier Fe-12Cr dans le CO2 à 550°C. Il est montré qu’en fonction de la valeur de ces paramètres, il est possible de former une couche d’oxyde fine protectrice en surface sans carburation. Un modèle permettant de rendre compte de l’ensemble des résultats expérimentaux est proposé. / In the framework of the development of Sodium Fast Reactors in France, supercritical carbon dioxide integrated in the Brayton cycle is proposed as new cycle energy conversion system to replace current steam generators. Ferritic-Martensitic steels with 9-12 wt% Cr are good candidates for heat exchanger application because they have good mechanical properties up to a temperature of 600°C, a high thermal conductivity, a low coefficient of thermal expansion and a lower cost than that of austenitic steels. However, it has been found that these steels present a high parabolic oxide growth rate and a strong carburization in the temperature and pressure conditions of the SC-CO2 cycle (550°C, 250 bar).This study aims to investigate the influence of different parameters (impurities present in CO2, thermal ramp rate and surface state) on the oxidation mechanism of a Fe-12 Cr steel in CO2 at 550°C. It has been shown that depending on these parameters, a thin protective oxide scale without any strong carburization can be obtained. A model is proposed to explain the experimental results.

As várias possibilidades de aplicações tecnológicas que o diamante permite, na indústria de dispositivos, impulsionaram os avanços de fabricação de amostras de diamante sintético de alta qualidade. O cristal de diamante crescido, do grafite, pela técnica de alta pressão e alta temperatura (HPHT - High Pressure-High Temperature), utiliza ligas de metais de transição como solvente-catalizadores, que produzem contaminação das amostras. Dentre as várias impurezas de metal de transição introduzidas no material resultante, as impurezas de níquel são as mais bem caracterizadas, pois os centros relacionados ao Ni apresentam características únicas nestas amostras sintéticas. Apesar das ligas de cobalto serem as mais utilizadas como solvente-catalizador no crescimento de diamante sintético, defeitos relacionados a sua presença, no material resultante, não têm sido identificados com a mesma facilidade como aqueles relacionados aos do níquel. Medidas de absorção óptica e de ressonância paramagnética eletrônica têm identificado vários centros relacionados com a impureza de níquel e alguns centros relacionados com a impureza de cobalto em diamante, tanto isolados como formando complexos, que envolvem defeitos intrínsecos e/ou dopantes. Entretanto, existem ainda muitas dúvidas e controvérsias sobre a estrutura microscópica destes centros. / High quality synthetic diamond, growth out of graphite, has been achieved by the high pressure-high temperature (HPHT) methods. In order to speed up the process and allow to get macroscopic samples, 3d-transition metal alloys have been used as solvent-catalysts. Those transition metals (TM) end up contaminating the samples, generating electrically and optically active centers. Nickel was the first transition metal impurity unambiguously identified in synthetic diamond, ever since, several nickel-related active centers have been observed. Although cobalt has been the most widely used solvent-catalyst to grow diamond, cobalt-related defects could not be identified as easily as the nickel-related ones. Electron paramagnetic resonance (EPR) and optical absorption measurements have identified several Ni-related centers and some Co-related centers in diamond, mostly isolated TM and TM-related complexes involving intrinsic defects and/or dopants. However, there is considerable controversy about the microscopic structure of those centers. We present a theoretical investigation on the structural and electronic properties of nickel and cobalt impurities in diamond. The atomic structures, symmetries, formation and transition energies, and hyperfine parameters of isolated interstitial and substitutional Ni and Co, as well as of the Ni-divacancy, Co-divacancy, Co-divacancy-nitrogen, Ni-B, and Ni-N complexes were computed by using ab initio total energy methods. Here we used the spin-polarized full-potential linearized augmented plane wave (FPLAPW) method. The calculations were performed within the framework of the density functional theory and considered the supercell approach. Our results are discussed in the context of the microscopic models which have been proposed to explain the active centers identified in synthetic diamond. Based on our results, we confirm some microscopic models and we ultimately propose new ones which unifies several experimentally identified impurities.

Ferromagnetismo itinerante permanece um problema elusivo em Física. O fenômeno resulta da competição entre interação eletrônica e efeitos de muitos corpos e não pode ser tratado perturbativamente. Particularmente em uma dimensão, teoremas proíbem fases ferromagnéticas em T = 0 para modelos de rede com hopping de primeiros vizinhos. Nos últimos vinte anos, entretanto, apareceram modelos na literatura que estendem o hopping para além de primeiros vizinhos e para os quais ordem ferromagnética foi rigorosamente estabelecida. Praticamente todas as demonstrações da existência de ferromagnetos unidimensionais são feitas em fase isolante (com exceção de casos patológicos, como repulsão infinita). Isto nos levou a investigar o acoplamento entre os setores de spin e carga no regime fortemente interagente quando se dopa o sistema, o que introduz pontos de Fermi pF e -pF. Encontramos, com teoria de perturbação, singularidades logarítmicas na autoenergia do mágnon quando seu momentum é pF ou -pF. Derivamos uma teoria de campo efetiva para o espalhamento em torno desses pontos entre os mágnons e férmions sem spin (que representam o setor de carga). O modelo efetivo é similar ao modelo Kondo, que consiste de uma impureza magnética localizada acoplada localmente com um mar fermiônico por uma interação de troca entre spins. Em nosso modelo, há, na realidade, um pseudospin que indica se o momentum de uma partícula é próximo de pF ou de -pF e o mágnon se comporta como uma impureza móvel. A mobilidade da impureza leva a uma relação de dispersão para os férmions dependente do pseudospin da impureza. / Itinerant ferromagnetism remains an elusive problem in Physics. The phenomenon arises from a competition between electronic interaction and many-body effects and cannot be treated perturbatively. Particularly in 1D, there are rigorous proofs that forbid ferromagnetic phase for lattice models with nearest-neighbours hopping only. In the last twenty years, however, models with hopping beyond nearest-neighbours were proposed in the literature and for which ferromagnetic phase was rigorously established. Virtually every proof of the existence of one-dimensional ferromagnets is done in an insulator phase (disregarding some pathological cases, such as infinite electronic repulsion). That motivated us to investigate the coupling between spin and charge sectors in the strongly interacting regime when we dope the system, introducing two Fermi points, pF and -pF. We found out, through perturbation theory, logarithmic singularities in the magnon selfenergy when its momentum is pF or -pF. To understand them, we derived an effective field theory for the scattering between magnons and spinless fermions (which represent the charge sector) close to these points. The effective model resembles the Kondo model, which describes a magnetic impurity locally coupled to a fermionic sea through spin exchange interaction. In our model, there is actually a pseudospin that indicates if a particle momentum is closest to pF or -pF and the magnon behaves as a mobile impurity. The impurity mobility leads to a fermionic dispersion relation that depends on the impurity pseudospin.