Thesis (M.S.)--University of Wisconsin--Madison, 1964. / eContent provider-neutral record in process. Description based on print version record. Bibliography: l. 74-78.

Orientador : Osvair Vidal Trivisan / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Campinas / Made available in DSpace on 2018-07-16T17:53:48Z (GMT). No. of bitstreams: 1 Pizarro_JorgeOscardeSant'Anna_M.pdf: 2484026 bytes, checksum: c78b0bc07ba939e4cf3cabce75a728c7 (MD5) Previous issue date: 1989 / Resumo: O sucesso alcançado pelos métodos térmicos de recuperação, motivou o surgimento, na década passada, dos primeiros trabalhos sobre a utilização de ondas eletromagnéticas como geradoras de calor em reservatórios de petróleo. Esta geração é obtida através de três técnicas diferentes, denominadas de aquecimento elétrico, indutivo e dielétrico. O objetivo do presente trabalho foi o de desenvolver um modelo numérico que pudesse simular adequadamente os efeitos do método de aquecimento elétrico na recuperação de petróleo. O princípio básico deste método consiste na geração de uma potência térmica através do fluxo de corrente elétrica em um circuito constituído pela água de formação e dois ou mais poços de petróleo. O modelo computacional. desenvolvido, considera o fluxo de duas fases (óleo e água), em um reservatório horizontal cilíndrico, com um poço no centro. São estudadas quatro configurações elétricas diferentes, o que levou ao desenvolvimento de uma formulação bidimensional, nas direções radial e angular. Os fenômenos que ocorrem no reservatório são representados por 4 equações governantes. A equação da eletricidade é resolvida separadamente enquanto as restantes (Óleo, Água e Energia) são resolvidas simultaneamente, através de uma formulação totalmente implícita, utilizando-se o método de Newton para tratamento das não-linearidades. Os resultados apresentados compreendem a validação do modelo, o ajuste aos dados práticos do teste de campo de Rio Panon na bacia Potiguar e ainda diversas extrapolações realizadas / Abstract: Due to the success of the thermal methods or oil recovery, the research and application of electromagnetic waves to generate heat in reservoirs was boosted in the last decade. The heat can be generated through three different techniques: electric, inductive and dielectric heating. The aim of this work was to develop a numerical model to simulate properly the effects of the method of oil recovery through electric heating. The fundamental principle in this method is the generation of heating power in the reservoir by flowing electric current in a circuit formed by the formation water and two or more wells. The computational model developed considers the flow of two phases - oil and water - in a horizontal and cylindrical reservoir with a centered well. Four different electric configurations were studied and a two-dimensional formulation in the angular and radial directions was developed. Four governing equations are used to model the reservoir: Two mass balance equations, for oil and water phase, and two energy balance equations, for thermal and electric energy. The electrical energy balance equation is solved separately, while the others are solved simultaneously by a fully implicit formulation that makes use of Newton's method to handle the nonlinearities. The results presented consist or the validation of the model, its application to a field test conducted in Rio Panon field in the Potiguar Basin in Brazil, and some idealized cases. In all cases that were run the reliability or the model was analyzed and proved satisfactory / Mestrado / Mestre em Engenharia de Petróleo

Thesis (Ph. D.)--University of Hong Kong, 2002. / Includes bibliographical references (leaves 187-194).

Dans cette thèse, nous étudions quelques modèles de flux migratoire. Nous sommes intéressés par le pays d’origine du migrant ainsi que par son pays d’accueil. Plus précisément, nous étudions les modèles où la probabilité de migration desagents dépend de leur capital humain (essentiellement l’éducation). Il y a deux cas importants qu’il convient de distinguer : le cas où les individus migrent avec le capital humain hérité de leurs parents et le cas le plus difficile, à solutions multivoques, lorsque les individus migrent avec le capital humain qu’ils auront dans le futur.Dans le premier cas, nous retrouvons les résultats obtenus la littérature. De plus, nous étendons aux cas de populations non constantes et nous proposons d’autres modèles. Dans le second cas, où les individus peuvent migrer en fonction de leurcapital humain futur, nous proposons différents mécanismes de sélection où les convergences vers une unique valeur de capital humain sont démontrées à chaque fois. / In this thesis, we study some migration models from a mathematical point of view. We are interested by the country of origin of migrant as well as in his host country.More precisely, we study the models where the probability of migration of individuals depends on their human capital (essentially education). There are two important cases to be distinguished : the case where individuals migrate with thehuman capital inherited from their parents and the more difficult case -since it is generally a multivalued case- where the individuals migrate with the human capital they will obtain in the future.In the first case, we obtain some results similar to the ones found in literature. Moreover, we study the case of non constant populations and we propose other models. In the second case, where the individuals can migrate following the human capital they will have in the future, we obtain different selection mechanisms for which the human capital converges to a unique value at each time.

This thesis examines the carnivalesque strategies evident in the short story "Confabulacion de la arana" by the Cuban writer, Guillermo Vidal. Two particular perspectives are used here. First, an analysis of the narrator and the narrative structure is made in which the contribution of the narrative strategies present in the text are explored. To do this, the methodological framework of literary carnivalization offered by the Russian critic Mijail Bajtin has been used, foregrounding his basic argument that carnival, as a social practice, is intrinsically subversive since it abolishes all forms of hierarchy and convention present in society during non-carnival time. By extending his theory to those genres of literature in which the elements of carnival are transcribed, Bajtin insists that carnival and carnivalized literature are potentially subversive since they contest conventional structures and frameworks. The narratological models and categories outlined by Gerard Genette and Mieke Bal allow consideration of the variety of pronouns through which the story is narrated and text's representation of the various speech acts. Unlike traditional narratives which are based on the use of a single pronoun, narration in this text is conducted through continual and abruptly shifting changes of pronoun. Such a technique disrupts the stability afforded by a single narrative voice and a narrative function based on ambivalence and plurality becomes evident. Secondly, the carnival theme and its relationship to the Bajtin's theory of the carnivalesque is examined. It is the contention here that "Confabulacion de la arana" may be read as a satire of contemporary Cuban society. Through the process of the continual debasement of the main character, the representative here of authority in Cuba, the story critiques the social and political values in force in Cuba today.

Resprouting is an important means of plant regeneration especially under conditions that do not favour regeneration through seeding such as frequent disturbances, low productivity, unfavourable soil conditions, extreme cold and limited understorey light availability. Sprouts may be advantageous over seedlings because they have higher survival and growth rates than seedlings, since they use resources from parent plants unlike seedlings that have to acquire their own resources. Resprouting is well documented for ecosystems that experience severe disturbances that damage aboveground biomass. For example, resprouting is important for plant persistence against fire in fire-prone savannas and Mediterranean shrub-lands, and hurricanes and cyclones in tropical forests. In these ecosystems, resprouting often results in multi-stemming, because this dilutes the risk of damage among many stems, improving the chances of individual survival. This study was conducted at coastal dune forest at Cape Vidal in north-eastern South Africa, where there is a high incidence of multi-stemmed trees due to resprouting in response to chronic disturbances of low severity. This study examines (1) the importance of resprouting to tree survival and dynamics in an environment where disturbance severity is low but pervasive, and (2) how this resprouting strategy differs from the more familiar sprouting response to severe disturbances such as fire and hurricanes. Analysis of the relationship between multi-stemming and a number of disturbances potentially causing multi-stemming revealed that stem leaning and substrate erosion were the most important disturbances associated with multi-stemming. There were fewer multistemmed trees on dune slacks that had a stable substrate and were protected from sea winds than on dune crests and slopes that had unstable substrate and were exposed to sea winds. Trees resprouted and became multi-stemmed from an early stage to increase their chances of survival against leaning caused by strong sea winds and erosion, and occasional slumping of the unstable dune sand substrate. These low severity disturbances are persistent and are referred to as chronic disturbances in this thesis. As a result of these chronic disturbances, both single and multi-stemmed trees had short stature because taller individuals that emerged above the tree canopy would be exposed to wind damage. Under chronic disturbances plants may manifest a phylogenetically determined sprouting response. However, in this study resprouting and multi-stemming were the results of the tree-disturbance interaction and not a property of a plant or species and were not phylogenetically constrained. Because the disturbances are predominantly of low severity, leaning trees were able to regain the vertical orientation of the growing section by turning upward (a process referred to as ‘turning up’ in this study) and hence survive without resprouting. Species that were prone to turning upward had a low incidence and degree of leaning of their individuals, low frequency of loss of primary stems and high abundance of individuals. Although turning up is less costly to the individual than resprouting, it could only be used by leaning trees that had small angles of inclination and were not eroded. High intensities of the latter require that individuals resprout to survive. The form and function of resprouting varied between seedlings and juvenile and mature trees. Resprouting in seedlings resulted in a single replacement shoot, unlike sprouting in juvenile and mature trees that resulted in multi-stemmed trees. Like sprouting in juvenile and mature trees, sprouting in seedlings was not phylogenetically constrained. Resprouting in seedlings increased seedling persistence; hence species with more sprout seedlings had larger individual seedlings and seedling banks. Resprouting in seedlings increased the chances of seedling recruitment, whereas resprouting in juvenile and mature trees increased the chances of an established plant maintaining its position in the habitat. After disturbances of high severity, which destroy the photosynthesizing parts, plants resprout using carbohydrates stored below- or above ground. In this study, good resprouters stored more carbohydrates both below- and above ground than poor resprouters. The carbohydrates were mobilized for resprouting after disturbance. More carbohydrates were stored in stems than in roots because the prevailing disturbances were mostly of low severity and hence above ground resources were readily available. Similar to storage by plants in severely disturbed habitats, carbohydrates were stored by reserve formation, which competes for carbohydrates with growth and maintenance and forms permanent storage, rather than accumulation, which temporarily stores carbohydrates in excess of demands for growth and maintenance. Stored carbohydrates are not necessary for resprouting of plants after disturbances of low severity because they can resprout using resources remobilized directly from the disturbed photosynthesizing parts. However, in this study, stored carbohydrates served as a bet-hedge against occasional severe disturbances that occurred in addition to chronic disturbances. Allocation of carbohydrates to permanent storage diverts them from growth and reproduction and hence good resprouters had lower growth rates, seed output, seed size and seedling recruitment than poor resprouters. However, the costs of these traits that resulted in low recruitment from seed by good resprouters, were compensated for by high persistence of established individuals of good resprouters through recruitment of sprout stems. This study demonstrates that resprouting is not only advantageous in severely disturbed environments, but also in environments where disturbances are of low severity but nevertheless confer an advantage on individuals that persist. Thus in forest environments where aboveground biomass is seldom destroyed and individuals are relatively long-lived, resprouting can confer significant fitness and selective advantage on individuals. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Univ. Católica Portuguese., Diss.--Lisboa, 2002. / Mit engl Zsfassg.

No description available.

Uma análise histórica dos primeiros estudos geográficos demonstra que a associação entre a Geografia e a Medicina ocorre desde tempos remotos, abrangendo a interface entre os elementos como saúde, meio ambiente e espaço. Este estudo procurou demonstrar as influências que os geógrafos Vidal de La Blache e Maximilien Sorre exerceram sobre a obra de Josué de Castro. Estas influências podem ser constatadas desde as primeiras obras de Castro relacionadas à espacialização da saúde, ainda muito impregnadas pelo possibilismo vidalino e pela utilização de conceitos próprios desta escola geográfica, até o lançamento dos livros Geografia da Fome e Geopolítica da Fome, em que a visão ecológica de Sorre e o contato com outras ciências humanas ampliaram o horizonte crítico das obras castrinas. / A historical analysis of the first geographic knowledge shows that the association between Geography and Medicine occurs since ancient times comprising the interface among subjects as health, environment and space. This essay is an attempt to demonstrate the influences which geographers Vidal de la Blanche and Maximilien Sorre carried out on the Josué de Castros work. These influences can be verified since the initial Castros works concerned with the spacialization of health, works that are still very impregnated with the Vidals possibilism and with this geographic school own concepts, until the edition of the books The geography of Hunger and the Geopolitics of Hunger, in which Sorres ecological perspective and contact with other human sciences amplify the critical horizon of Castros works.

Uma análise histórica dos primeiros estudos geográficos demonstra que a associação entre a Geografia e a Medicina ocorre desde tempos remotos, abrangendo a interface entre os elementos como saúde, meio ambiente e espaço. Este estudo procurou demonstrar as influências que os geógrafos Vidal de La Blache e Maximilien Sorre exerceram sobre a obra de Josué de Castro. Estas influências podem ser constatadas desde as primeiras obras de Castro relacionadas à espacialização da saúde, ainda muito impregnadas pelo possibilismo vidalino e pela utilização de conceitos próprios desta escola geográfica, até o lançamento dos livros Geografia da Fome e Geopolítica da Fome, em que a visão ecológica de Sorre e o contato com outras ciências humanas ampliaram o horizonte crítico das obras castrinas. / A historical analysis of the first geographic knowledge shows that the association between Geography and Medicine occurs since ancient times comprising the interface among subjects as health, environment and space. This essay is an attempt to demonstrate the influences which geographers Vidal de la Blanche and Maximilien Sorre carried out on the Josué de Castros work. These influences can be verified since the initial Castros works concerned with the spacialization of health, works that are still very impregnated with the Vidals possibilism and with this geographic school own concepts, until the edition of the books The geography of Hunger and the Geopolitics of Hunger, in which Sorres ecological perspective and contact with other human sciences amplify the critical horizon of Castros works.