Thesis (Ph. D.)--University of Texas at Austin, 1998. / Includes bibliographical references.

This thesis discusses the recent developments to the electric propulsion plume code DRACO as well as a validation and sensitivity analysis of the code using data from an AFRL experiment using a Busek 200 W Hall Thruster. DRACO is a PIC code that models particles kinematically while using finite differences schemes to solve the electric potential and field. The DRACO code has been recently modified to improve simulation results, functionality and performance. A particle source has been added that uses the Hall Thruster device code HPHall as input for a source to model Hall Thrusters. The code is now also capable of using a non-uniform mesh that uses any combination of uniform, linear and exponential stretching schemes in any of the three directions. A stretched mesh can be used to refine simulation results in certain areas, such as the exit of a thruster, or improve performance by reducing the number of cells in a mesh. Finally, DRACO now has the capability of using a DSMC collision scheme as well as performing recombination collisions. A sensitivity analysis of the newly upgraded DRACO code was performed to test the new functionalities of the code as well as validate the code using experimental data gathered at AFRL using a Busek 200 W Hall Thruster. A simulation was created that attempts to numerically recreate the AFRL experiment and the validation is performed by comparing the plasma potential, polytropic temperature, ion number density of the thruster plume as well as Faraday and ExB probe results. The study compares the newly developed HPHall source with older source models and also compares the variations of the HPHall source. The field solver and collision model used are also compared to determine how to achieve the best results using the DRACO code. Finally, both uniform and non-uniform meshes are tested to determine if a non-uniform mesh can be properly implemented to improve simulation results and performance. The results from the validation and sensitivity study show that the DRACO code can be used to recreate a vacuum chamber simulation using a Hall Thruster. The best results occur when the newly developed HPHall source is used with a MCC collision scheme using a projected background neutral density and CEX collision tracking. A stretched mesh was tested and proved results that are as accurate as a uniform mesh, if not more accurate in locations of high mesh refinement. / Master of Science

Dracaena draco is native to subtropical arid area of Macaronesia. Horizontal precipitation is an important component of water balance in such arid and semiarid areas. Morphological, anatomical and physiological adaptations to drought stress and demonstrated ability to absorb condensed water on the leaves into the stem tissues were discovered at D. draco. The aim of performed measurements was to quantify the importance of horizontal precipitation as an additional source of moisture during the critical period of juvenile stages of D. draco in Anaga (Tenerife). Measuring sets based on lysimeters measured the weight changes of seedlings placed in flowerpots hanging on the weights. The results of measurement proved that the seedlings can partly replace loss of water from evaporation by the water uptake from the atmosphere. Water uptake from the atmosphere took place mainly at night and the water output by transpiration predominated during the day. Horizontal precipitation replaced the evaporation by 6 to 10 % in the first period measured from October and did not replace the evaporation in the second period of measurements that started in January

This essay explores how in the Harry Potter series, J. K. Rowling's magical heroes function asparadigms whose roles reflect on issues of race, prejudice and racism. Those issues include goodand evil, socialism and aristocracy, purity and impurity, freedom and indebtedness. This essayfocuses on showing how those themes are reflected and confronted in the dipole between HarryPotter and Draco Malfoy. Additionally, the Critical Race Theory, a theory that examines howculture uses and assorts power and race in society, is implemented to show how race andprejudice are reflected in the magical world. By further analyzing Harry and Draco's upbringingand social milieus in relation to the theme of good vs. evil, the development of these characters ispresented in response to their contrasting surroundings. The paper concludes that thesecharacters evolve in the final novels and make conscious choices to achieve the common causeof defying evil, despite their opposing backgrounds. / Denna uppsats utforskar hur J. K. Rowlings magiska hjältar, i Harry Potter-serien, fungerar somen paradigm vars roller reflekterar frågor kring ras, fördomar och rasism. Dessa frågor inkluderargott och ont, socialism och aristokrati, renhet och orenhet, frihet och skuldsättning. Dennauppsats fokuserar på att visa hur dessa teman reflekteras och konfronteras i dipolen mellan HarryPotter och Draco Malfoy. Dessutom implementeras Critical Race Theory, en teori somundersöker hur kultur använder och sorterar makt och ras i samhället, för att visa hur ras ochfördomar återspeglas i den magiska världen. Genom att ytterligare analysera Harry och Dracosuppväxt och sociala miljöer i förhållande till temat ’gott mot ont’, presenteras dessa karaktärersutveckling som ett resultat av kontrasterande omgivning. Uppsatsen drar slutsatsen att dessakaraktärer utvecklas i de sista romanerna och gör medvetna val för att uppnå det gemensammamålet till att bekämpa det onda, trots deras motsatta bakgrunder.

Esta dissertação aborda o Direito Ático por um prisma axiológico. Admite a influência dos valores na formulação de normas e institutos, e destaca um valor que considera como dos mais importantes na cultura grega dos séculos V e IV a.C., a saber, a honra. Uma primeira parte do trabalho se propõe a delimitar a honra, distinguindo seu uso em dois sentidos principais de: valor que se tem, e de fenômeno da percepção deste valor. Uma segunda parte demonstra a origem do apreço pela honra e pela excelência na poesia épica, esclarecendo depois que posição a honra ocupa na escala grega de valores. Trata-se ainda da guerra como local para o nascimento e consolidação dos significados de honra de que dispomos, e em seguida, aborda a tormentosa situação enfrentada por Drácon por conta da prática da vingança privada, destacando a vinculação desta ao restabelecimento da honra e comentado as características da lei de homicídio de Drácon. A terceira parte dedica-se a detalhado exame de três institutos jurídicos Áticos que têm na honra sua razão de ser: perda dos direitos civis, atimía; serviços ao povo de Atenas, liturgias; a tratamento e punição da hýbris. / The present work examines Attic Law through an axiological perspective. Admits the role of values in forming norms and juridical institutes, focusing in a special value considered to be one of the main forms of excellence in 5th and 4th century: honor. The first part of the work delimits honor, indicating two meanings for the term: a value that the subject has, and the perception of such a value by others. A second part demonstrates the origin of the greek concern with honor and excellence in Homer´s epic poetry, establishing a post for honor in greek axiological rankings. Identifies war as the birthplace of the meanings of honor we discussed, and analyzes the difficult social condition that Draco had to face in its time, related to private revenge, emphasizing it connection with the theme of honor and commenting Draco´s Homicide Law. The third part brings a detailed exam of three of attic law´s institutes related to honor: disenfranchisement, atimía; public service in Athens, liturgies; treatment and punishment of hýbris.

Esta dissertação aborda o Direito Ático por um prisma axiológico. Admite a influência dos valores na formulação de normas e institutos, e destaca um valor que considera como dos mais importantes na cultura grega dos séculos V e IV a.C., a saber, a honra. Uma primeira parte do trabalho se propõe a delimitar a honra, distinguindo seu uso em dois sentidos principais de: valor que se tem, e de fenômeno da percepção deste valor. Uma segunda parte demonstra a origem do apreço pela honra e pela excelência na poesia épica, esclarecendo depois que posição a honra ocupa na escala grega de valores. Trata-se ainda da guerra como local para o nascimento e consolidação dos significados de honra de que dispomos, e em seguida, aborda a tormentosa situação enfrentada por Drácon por conta da prática da vingança privada, destacando a vinculação desta ao restabelecimento da honra e comentado as características da lei de homicídio de Drácon. A terceira parte dedica-se a detalhado exame de três institutos jurídicos Áticos que têm na honra sua razão de ser: perda dos direitos civis, atimía; serviços ao povo de Atenas, liturgias; a tratamento e punição da hýbris. / The present work examines Attic Law through an axiological perspective. Admits the role of values in forming norms and juridical institutes, focusing in a special value considered to be one of the main forms of excellence in 5th and 4th century: honor. The first part of the work delimits honor, indicating two meanings for the term: a value that the subject has, and the perception of such a value by others. A second part demonstrates the origin of the greek concern with honor and excellence in Homer´s epic poetry, establishing a post for honor in greek axiological rankings. Identifies war as the birthplace of the meanings of honor we discussed, and analyzes the difficult social condition that Draco had to face in its time, related to private revenge, emphasizing it connection with the theme of honor and commenting Draco´s Homicide Law. The third part brings a detailed exam of three of attic law´s institutes related to honor: disenfranchisement, atimía; public service in Athens, liturgies; treatment and punishment of hýbris.