Dissertations / Theses on the topic 'R3A2'

Ionizing radiation can have several different effects on cells, some are almost instantaneous such as the generation of DNA damage, other cellular responses take a matter of minutes or hours - DNA repair protein induction/activation, and others may take months or even years to be manifested - carcinogenesis. Human epithelial cell lines derived from both normal, non-neoplastic tissues and from a malignant source were cultured in order to examine several effects of ionizing radiation on such cell types. Cells not from a malignant source were previously immortalized by viral infection or by transfection with viral sequences. Simian virus 40 immortalised uroepithelial cells (SV-HUC) were found to be approximately a factor of two fold more radioresistant than cells of malignant origin (T24) in terms of unrepaired clastogenic damage i.e. assessment of micronuclei levels following irradiation. SV-HUC lines unlike T24 cells are non-tumourigenic when inoculated into nude athymic mice. SV-HUC lines proved very resistant to full oncogenic transformation using radiation and chemical carcinogens. However, morphological alterations and decreased anchorage dependant growth was observed in post carcinogen treated cells after appropriate cell culture conditions were utilized. The progression from this phenotype to a fully tumourigenic one was not recorded in this study. The ability of ionizing radiation to induce increased levels of the nuclear phosphoprotein p53 was also assessed using several different cell lines. SV- HUC and T24 cell lines failed to exhibit any increased p53 stabilization following irradiation. One cell line, a human papilloma virus transformed line (HPV) did show an approximate two fold increase of the wild type p53 protein after treatment with radiation. Only the cell line HPV showed any cell cycle delay, resulting in accumulation of cells in the G2/M compartment in post irradiation cell cycle analysis. The status of p53 was also assessed i.e. wild type or mutant conformation in all the above cells lines and two other control lines HOS (a human osteosarcoma cell line) and H Tori-3 (SV40 immortalised thyroid epithelial cells).

Les acides hydroxamiques (rconhoh) sont des molecules a tres fort pouvoir de chelation et ont ete largement etudies en tant qu'inhibiteurs de metalloproteases, enzymes responsables d'un grand nombre de maladies a caractere cancereux. Certains acides hydroxamiques ont egalement ete utilises comme agents depolluants ou comme agents extracteurs de metaux. Ce travail presente une methode nouvelle de synthese de ces molecules, en utilisant l'activite de transfert d'acyles de deux amidases (acylamide amidohydrolases) de la souche bacterienne rhodococcus sp. R312 : l'amidase generale et l'amidase enantioselective. Dans un premier temps, quelques acides hydroxamiques ont ete synthetises par voie chimique afin de permettre la mise au point d'une methode spectrophotometrique de dosage de ces molecules, basee sur les proprietes de complexation des hydroxamates avec fe(iii). L'etude des activites de transfert (spectre de substrat, constantes cinetiques, mecanisme reactionnel, effets inhibiteurs, enantioselectivite, etc) de chacune des deux enzymes est ensuite presentee, et permet d'apporter des elements sur la connaissance des amidases microbiennes, en particulier sur la geometrie de leur site actif. L'amidase generale (structure homotetramerique) catalyse la synthese d'acides hydroxamiques aliphatiques a tres courte chaine carbonee (c#2-c#3), par transfert du groupement acyle d'un amide sur une molecule d'hydroxylamine. Elle est egalement capable de catalyser ce transfert sur une molecule d'hydrazine afin de former des hydrazides. Le mecanisme reactionnel est de type bi bi ping pong. L'amidase enantioselective (structure homodimerique) catalyse, suivant le meme mecanisme, la synthese d'une gamme beaucoup plus large d'acides hydroxamiques (aliphatiques de c#2 a c#6, -amines, aromatiques ou heterocycliques) et presentent une (s)-enantioselectivite vis-a-vis des substrats -substitues. Par contre, cette enzyme ne catalyse pas la synthese d'hydrazides. Enfin, des essais d'immobilisation de l'amidase generale sont egalement decrits.

This dissertation investigates the dissimilar use of price and intrinsic information in product quality assessments by differentially familiar buyers. Further, the impact of price and intrinsic information in evaluating monetary sacrifice, product value and purchase intention are examined. In particular, the impact of differing degrees of buyer familiarity with the product is hypothesized to affect the extent to which price or intrinsic information is used to assess product quality. A secondary set of hypotheses posits relationships between different cues used in value perceptions and manifestations of behavioral intention, depending on buyer familiarity with the product. Pre-experimental work was conducted to accomplish numerous objectives. First, it was necessary to identify a product which exhibited an objective quality-price association in the marketplace that would be used in the experiment. Second, price and intrinsic cue levels were established through pretests. Third, with the assistance of experts, a scale was developed to determine subject familiarity with the product. Based on refinements dictated by pre-experimental work, data were collected to examine the effects of price and intrinsic cues on perceptions of quality, sacrifice, value and willingness to buy, in a 4x2 between subjects factorial design. Subjects' familiarity with the product was assessed and, depending on their degree of familiarity, their responses were analyzed in one of three similar experiments. Data were collected using both magnitude and category scaling procedures. The degree to which variations in the independent variable resulted in variations in responses were compared for the three differentially familiar groups to assess support for the hypotheses. In general, there is a great deal of support for the primary hypotheses, suggesting that unfamiliar, moderately familiar and highly familiar buyers display different cue utilization strategies while assessing product quality. It is likely that all subjects not having the same value for money resulted in relatively weak support for the secondary hypotheses. The implications of the findings are discussed from the perspectives of conceptual, methodological and analytical advances as well as practitioner relevance. The limitations of the research effort are outlined as are potential areas of future research.
Ph. D.

Most existing environmental chambers cannot simulate dynamically changing environmental conditions. Hence there is a need for a dynamically controlled artificial environment for plant studies. This project demonstrates the control of temperature, humidity and SO₂ concentration in a Continuous Stirred Tank Reactor (CSTR) system using feedback control through a computer. An IBM-PC was connected to the measuring instrumentation and control equipment through a data acquisition and control system. Temperature and humidity were controlled by an ON-OFF control scheme. Sulfur dioxide concentration was controlled by means of a modified proportional derivative control algorithm. The system is capable of achieving a wide range of temperatures (7°C to 40°C), humidities (30% to 97%), and SO₂ concentrations. Temperature is maintained within ±0.5°C of the desired value and humidity is controlled within ±4% of the desired value. Sulfur dioxide concentration is kept within ±10% of the desired concentration. It was found that as humidity increases, the supply rate of SO₂ must be increased to maintain a given concentration. Software response time is slow. This causes time lags in the modification of the controlled parameters to achieve desired values. The heating and cooling characteristics of the system can be improved by better insulation of the chamber walls. The system demonstrates that computerized feedback control is practical for application to controlling environmental parameters in a fumigation chamber.
Master of Science

A computer-aided design procedure has been developed to determine the minimum weight design solutions, for singly wound EE- and EI-cored inductors that perform the functions of energy storage and transfer in switching DC·DC power converters. Three converter topologies, namely the Buck, the Boost, and the Buck/Boost have been considered in implementing the closed form Lagrange Multiplier-based solution to the design problem.

A notable feature is the interactive use of design graphs to facilitate a trade-off study between the weight of the inductor, the total losses in the inductor and the peak current stress in the switching transistor and diode. Thus useful insight is obtained by bringing aspects of converter design into view. Practical core and magnetic material data from manufacturerâ s catalogs can be specified and the design optimized for the minimal weight.

Master of Science

"Cette recherche traite de l’étude de la nature et des obligations du mariage juif àpartir d’un point de doctrine traditionnelle du Talmud de Babylone voulant que D’ieu aituni l’homme et la femme quarante jours avant leur stade embryonnaire. S’ensuit uneséparation nécessaire de ces âmes dans leur vie terrestre avant de renouer contact par lemariage, appelé kiddushin, impliquant une union par et avec D’ieu. Cette sanctification,le mariage, répond à deux buts précis : la compagnie et la procréation.Une attention particulière sera portée au .écit du tout premier mariage de laCréation : celui de Adam et de Hava. Il est impossible de passer sous silence le récit de lacréation de la femme, puisque l’existence même des kiddushin en fut conditionnée. Noussituerons la place et l’influence que la femme peut avoir au sein du mariage, ainsi que lesqualités morales que doit rechercher un homme chez une femme."

There are six women's team sports recognized by the National Collegiate Athletic Association (NCAA): field hockey, basketball, soccer, volleyball, lacrosse, and softball. Associated with each of these sports are polling procedures conducted to indicate national rankings in terms of quality of performance. These polls generally are referred to as "Top Twenty Polls." Questionnaires were designed and mailed to the coaches and selection committee members associated with the two study sports: basketball and field hockey. Respondents were to rate a series of questions pertaining to either basketball or field hockey as to the relative importance in the ranking process of the content of each question. Returned questionnaires were compiled and a frequency analysis done on the questions. Analysis showed there to be no difference between sports. or among divisions within a sport as to the selection methodology used to develop a Top Twenty Poll. A model was developed to provide unbiased information to the selection committees designed to allow for comparisons which might otherwise not be available. Following analysis, the following variables were chosen for the model: win/loss record against common opponents, scoring margin, strength of schedule during the season, "credible" losses, record for the week, record for the season, record against teams 1-10 in the top twenty poll, record against teams 11-20 in the top twenty poll, and a performance quality indicator statistic.
M.S.

La pompe à chaleur industrielle très haute température (PAC THT) à compression mécanique de vapeur, fonctionnant à l'électricité, figure parmi l'une des technologies innovantes les plus efficaces permettant de valoriser les rejets thermiques industriels à basse et moyenne température (<90 °C). Néanmoins, compte tenu des besoins industriels actuels de chaleur, les niveaux de température cible atteignable par les PACs restent trop faibles et freinent fortement son implantation. Les procédés de séchage, dans leur grande majorité, rejettent des buées ou de la vapeur d'eau à moyenne température (50 °C-90 °C) et ont des besoins de chaleur à très haute température (110 °C-150 °C). Le grand écart de température entre la source et le besoin de chaleur ainsi que le niveau de température du besoin, font qu'aujourd'hui envisager l'intégration d'une PAC dans ce type de procédés relève d'un défi énergétique et technologique particulièrement intéressant, dont l'enjeu économique est considérable. Les présents travaux de recherche envisagent à l'aide d'une méthodologie générique d'optimisation de cycles thermodynamiques basée sur la minimisation de la production d'entropie dans les échangeurs de chaleur de déceler les architectures de PACs les plus efficaces d'un point de vue énergétique. L'analyse théorique a permis de déceler la haute efficacité énergétique des architectures transcritiques de PACs dans des conditions de grands glissements de température entre l'entrée et la sortie du besoin de chaleur. Le développement d'un démonstrateur de PAC transcritique très haute température fonctionnant au R32 (PAC T-THT R32) a permis d'une part de démontrer la faisabilité technique d'une PAC, pouvant atteindre la température cible de 120 °C en partant de 60 °C avec une source de chaleur disponible à 50 °C, et d'autres part de démontrer sa haute efficacité énergétique (COP = 4)
The mechanical vapour compression high temperature heat pump for industry using electricity is one of the most effective innovative technologies to recover the industrial waste heat at low and medium temperature (<90°C). However, given the current industrial heat needs, the heat pump target temperature levels remain too low and slow strongly its implantation. Overwhelmingly, the drying processes reject saturated moist air at middle temperature (50°C-90°C) and have heat needs at very high temperature (110°C-150°C). The large temperature difference between the source and the heat need and the level off temperature that is needed, today, makes the heat pump integration in such processes an interesting energy and technological challenge, whose economic stake is considerable. The present works tackle, with a generic methodology of thermodynamic optimisation cycles based on the entropy minimization in the heat exchangers, to identify the most efficiency heat pump architectures from an energy point of view. The theoretical analysis allowed to detect the transcritical heat pump architecture, in conditions of high temperature glides between the inlet and the outlet of the heat need. The development of a transcritical high temperature heat pump demonstrator using the R32 as working fluid allowed to demonstrate the technical feasibility of a heat pump that can reach the target temperature of 120°C from 60°C with an available heat source at 50°C, and to demonstrate its high energy efficiency (COP = 4)

This article investigates the influence of competition on price and product quality among Austrian camping sites, a market characterized by both horizontal (spatial) and vertical product differentiation. Theoretically, the effect of competition on quality is ambiguous and depends on the degree of cost substitutability between output and quality. Estimating a system of equations shows that intense competition has a positive impact on product quality and a negative effect on prices (conditional on quality). As high quality is associated with high prices, the total effect of competition on prices is rather small.

This study aimed to facilitate evaluation of alternative refrigerants for the air conditioner market. In order to achieve this target, two objectives were set. The first being the identification of alternative refrigerant with regard to regulations and trends. The second being enabling of thermodynamic evaluation of refrigerants for single components in air conditioners via design and installation of a test rig. A literature review was conducted to investigate the regulations, standards and trends for nine regions with high market shares. Furthermore, refrigerant substitutes for R410A and R22 where identified. The literature showed strong indications that a global HFC phase down is on the horizon, but that the approach and urge for such a phase down varies between regions where three main priorities could be seen; efficiency, GWP values and safety. Comparing these priorities with simulated refrigerant characteristics such as Carnot efficiency, GWP values, volumetric capacity and the liquid density using RefProp, identified alternatives. Further the literature showed that the lower flammability limit (LFL) and the amount of charge allowed were limiting factors for flammable refrigerant. There are many new refrigerants that could have less charge for the same capacity the LFL however restricts the refrigerants like R290, R441A and R443A only to be used in small systems. A test rig was designed and constructed in order to enable testing of single components in air conditioners. To verify the test rig, tests conducted with an evaporator using two refrigerants: R410A and R32. The reliability and validity of the tests was studied by comparing the results from the air side and refrigerant side, via uncertainty calculations using the GUM method and by a thermodynamic evaluation. The results of the repetition tests showed an expanded uncertainty, with a confidence interval of 95%, of 26 W for a cooling capacity of 2190W for R410A (Q̇evap,R410A=2190±26W). For R32 the expanded uncertainty was 27W for a cooling capacity of 2795W (Q̇evap,R32=2795±27W). Also the test rig was verified to be used for analyzing detailed evaluation of evaporators such as looking at heat transfer and the differential pressure drop. Further the study presented six conclusions: When evaluating refrigerants regional priorities between efficiency, safety and GWP values, refrigerant characteristics and type of unit need to be considered. Safety standards need to be more acceptable towards flammable refrigerants in order to meet low GWP targets. The change in market trends leads to new roles for the refrigerant and compressor suppliers and put higher demand on air conditioner manufacturers to consider refrigerant characteristics in product development. The importance of experimental thermodynamic evaluation on refrigerants effect on single components is increasing. Performance of different refrigerant for single components can be evaluated for optimizing cycle performance. Leapfrogging in the developing world can lead to a faster introduction of low GWP refrigerants.

Recentemente, observa-se o crescimento do número de trocadores de calor baseados em microcanais devido a necessidade de transferência de elevadas taxas de calor utilizando dispositivos compactos. Tubos de calor, trocadores de calor compactos para equipamentos eletrônicos e controle térmico de satélites, sistemas de condicionamento de ar para automóveis, escritórios e residências são exemplos de aplicações para condensação em canais de diâmetro reduzido. No entanto, na literatura encontra-se reduzido número de estudos experimentais tratando da condensação no interior de canais com diâmetros inferiores a 3 mm, os quais geralmente envolvem refrigerantes com elevado potencial de aquecimento global (GWP). Neste contexto, o presente estudo apresenta uma revisão crítica da literatura envolvendo critérios de transição entre padrões de escoamento, perda de pressão por atrito e coeficiente de transferência de calor durante a condensação no interior de canais convencionais e de micro-escala (minicanais). Levantou-se resultados para o gradiente de pressão por atrito e coeficiente de transferência de calor em aparato experimental localizado na Universidade de Pádua (Università Degli Studi di Padova) para os fluidos refrigerante R1234ze(E) e R32 (GWP de 550 e 6, respectivamente), temperatura de saturação de 40°C, fluxo de calor até 35 kW/m², grau de sub-resfriamento da parede entre 2 e 10 K, velocidade mássicas entre 55 e 275 kg/m²s e título de vapor de 0 a 1. Os dados foram levantados em seção de teste composta por 36 minicanais com diâmetro hidráulico de 1,6 mm e geometria retangular, com o efeito de resfriamento obtido através de água resfriada escoando em contra-corrente ao refrigerante. Os dados experimentais levantados para o gradiente de pressão por atrito e o coeficiente de transferência de calor foram comparados com métodos de previsão da literatura, concluindo que as correlações propostas por Jige, Inoue e Koyama (2016) fornecem as melhores previsões. O comportamento do coeficiente de transferência de calor foi analisado com foco nos mecanismos físicos predominantes durante a condensação. A partir desta análise concluiu-se o predomínio de efeitos de tensão superficial em velocidades mássicas reduzidas e de arrasto em velocidades mássicas elevadas. Este estudo também apresenta uma avaliação comparativa do desempenho dos refrigerantes R1234ze(E) e R32 em relação ao R134a (GWP de 1300) baseada na taxa de transferência de calor por unidade de potência de bombeamento e no potencial de transferência de calor, conforme o critério proposto por Cavallini et al. (2010). Esta análise revelou o desempenho superior para o refrigerante R32 seguido do R134a, com o R1234ze(E) apresentando o pior resultado, independentemente da velocidade mássica.
Recently, micro-scale channels are increasingly being used to combine high heat transfer rates and high degree of compactness. Condensation inside small diameter channels can be found in several applications such as heat pipes, thermal management of electronic equipments, spacecraft thermal control, automotive and residential air conditioning systems, heat pumps and refrigeration systems. However, despite of its importance, few studies concerning condensation inside minichannels (DH < 3 mm) involving low GWP (Global Warming Potential) refrigerants are found in the literature. In this context, initially, this study presents a critical review on the literature involving transition criteria on two-phase flow patterns for micro- and macro-scale conditions, frictional pressure drop and heat transfer coefficient during condensation inside channels. Experimental results for frictional pressure gradient and heat transfer coefficient obtained in apparatus located at the University of Padua (Università Degli Studi di Padova) are carefully analysed. The database includes results for the refrigerants R1234ze(E) and R32 (GWP of 550 and 6, respectively), saturation temperature of 40°C, heat flux up to 35 kW/m², fluid and wall temperature diference up to 10 K, mass velocity in the range of 55 to 275 kg/m²s and vapor quality between 0 and 1. The test section is composed of 36 rectangular minichannels with hydraulic diameter of 1.6 mm. The refrigerant is cooled by water flowing. From a comparison of experimental data for frictional pressure drop and heat transfer coefficient, and prediction methods available in literature, the methods proposed by Jige, Inoue e Koyama (2016) were ranked as the best ones. During the data analyses, focus was put on in order to relate the heat transfer coefficient behavior with the prevailing mecanisms during condensation. Based on this carefull analysis, the predominance of surface tension effects was pointed out under conditions of low mass velocities and condensation inside rectangular minichannels. On the other hand, for high mass velocities shear stress effects prevailed. Also, it has been presented a comparative evaluation of the performance of the refrigerants R1234ze(E), R32 and R134a (GWP of 1300) based on the following criteria: (i) heat transfer rate per unit of power pumping; and (ii) a penalty factor based on the heat transfer potential proposed by Cavallini et al. (2010). According to this evaluation, independently of the mass velocity, the refrigerant R32 was ranked as the one presenting the best performance, followed by R134a ranked as the second best. The refrigerant R1234ze(E) provided the worst performance among them all.

Les problèmes liés à l'environnement et plus particulièrement à la couche d'ozone et à l'effet de serre sont fortement d'actualité. Depuis 1987, le protocole de Montreal impose une nouvelle réglementation en terme d'utilisation des fluides frigorigènes pour les pays industrialisés. Pour appliquer ce protocole, dans de bonnes conditions techniques et économiques, l'industrie a besoin de données thermophysiques concernant les nouveaux fluides frigorigènes. Afin de réaliser des mesures d'équilibre liquide vapeur sur les fluides frigorigènes, deux techniques expérimentales ont été choisies et utilisées. Il s'agit d'une technique statique-analytique avec échantillonnage des phases (analyse par chromatographie en phase gazeuse) et d'une technique synthétique avec une cellule à volume variable. Quatre systèmes binaires et un système ternaire ont été étudiés: 1,1,1,2,3,3,3-heptafluoropropane (R227ea)+ propane (R290); difluorométhane (R32) + R290; R32 + R290, dioxyde de carbone (CO2) + R227ea et R32+R290+R227ea. Pour réaliser le traitement des données et la modélisation, un progiciel a été développé: THERMOPACK. Ce progiciel a permis de comparer les résultats expérimentaux obtenus à des valeurs disponibles dans la littérature, de calculer la ligne des points critiques et de calculer la position des azéotropes.

The empirical literature on mergers, market power and collusion in differentiated markets has mainly focused on methods relying on output and/or panel data. In contrast to this literature we suggest a novel approach that allows for the detection of collusive behavior among a group of firms making use of information on the spatial structure of horizontally differentiated products. By estimating best response functions using a spatial econometrics approach, we focus on differences in the strategic interaction in pricing between different groups of firms as well as on differences in price levels. We apply our method to the market for ski lift tickets using a unique data set on ticket prices and detailed resort-specific characteristics covering all ski resorts in Austria. (authors' abstract)
Series: Department of Economics Working Paper Series

Pour rendre compte de l'émergence de l'accessibilité comme nouvelle catégorie d'intervention publique au lendemain de la loi du 30 juin 1975, nous avons fait le choix de partir d'un travail empirique en nous intéressant aux pratiques passées et actuelles des politiques mises en oeuvre dans deux entreprises de transport urbain de voyageurs notamment à travers une observation participante de trois ans dans l'une d'entre elle. L'objectivation est menée grâce au recours à la littérature sociologique, en particulier aux écrits sur les référentiels, l'entreprise de morale, l'innovation technologique et les mouvements sociaux.
Ces notions nous ont permit de révéler les ressorts du changement intervenu dans les politiques déployées. Celles-ci passent de deux ensembles de solutions construites en faveur de populations médicalement identifiées comme handicapées à des solutions intégrées, disponibles pour tous, cohabitant avec du transport spécialisé. L'évolution est rendue possible par la conjonction de facteurs conceptuels, techniques et législatifs utilisés par un réseau de militants pour imposer un traitement intégré de l'accessibilité. Celui-ci est devenu une référence standard et est institutionnalisé dans la loi du 11 février 2005 pour l'égalité des chances. Le premier type d'accessibilité est intimement lié au référentiel du handicap alors que le second possède son propre référentiel et s'est autonomisé vis à vis du handicap. Il y a eu invention de l'accessibilité comme nouvelle forme sociale révélatrice d'une conception du traitement de l'altérité dans notre société. Ses formes nous éclairent sur la façon d'envisager la place des personnes handicapées dans la société.