Electromagnetic scattering from cylindrically and spherically stratified bodies

A method is developed for calculating the electromagnetic field scattered by certain types of bodies. The bodies consist of inhomogeneous media whose constitutive parameters vary only with the distance from some axis or point of symmetry. The method consists in an extension of the invariant imbedding method for treating wave problems. This method, which is familiar in the case of a one-dimensional inhomogeneity, is extended to handle special types of two and three-dimensional inhomogeneities. Comparisons are made with other methods which have been proposed for treating these kinds of problems. Examples of applications of the method are given, some of which are of interest in themselves.

I. Stokes flow past a thin screen. II. Viscous flows past porous bodies of finite size

Part I

The slow, viscous flow past a thin screen is analyzed based on Stokes equations. The problem is reduced to an associated electric potential problem as introduced by Roscoe. Alternatively, the problem is formulated in terms of a Stokeslet distribution, which turns out to be equivalent to the first approach.

Special interest is directed towards the solution of the Stokes flow past a circular annulus. A "Stokeslet" formulation is used in this analysis. The problem is finally reduced to solving a Fredholm integral equation of the second kind. Numerical data for the drag coefficient and the mean velocity through the hole of the annulus are obtained.

Stokes flow past a circular screen with numerous holes is also attempted by assuming a set of approximate boundary conditions. An "electric potential" formulation is used, and the problem is also reduced to solving a Fredholm integral equation of the second kind. Drag coefficient and mean velocity through the screen are computed.

Part II

The purpose of this investigation is to formulate correctly a set of boundary conditions to be prescribed at the interface between a viscous flow region and a porous medium so that the problem of a viscous flow past a porous body can be solved.

General macroscopic equations of motion for flow through porous media are first derived by averaging Stokes equations over a volume element of the medium. These equations, including viscous stresses for the description, are more general than Darcy's law. They reduce to Darcy's law when the Darcy number becomes extremely small.

The interface boundary conditions of the first kind are then formulated with respect to the general macroscopic equations applied within the porous region. An application of such equations and boundary conditions to a Poiseuille shear flow problem demonstrates that there usually exists a thin interface layer immediately inside the porous medium in which the tangential velocity varies exponentially and Darcy's law does not apply.

With Darcy's law assumed within the porous region, interface boundary conditions of the second kind are established which relate the flow variables across the interface layer. The primary feature is a jump condition on the tangential velocity, which is found to be directly proportional to the normal gradient of the tangential velocity immediately outside the porous medium. This is in agreement with the experimental results of Beavers, et al.

The derived boundary conditions are applied in the solutions of two other problems: (1) Viscous flow between a rotating solid cylinder and a stationary porous cylinder, and (2) Stokes flow past a porous sphere.

Das narrativas maravilhosas do oriente às narrativas do ocidente um perfil da influência muçulmana na construção do universo feminino medieval ibérico

Ao longo do processo histórico nas culturas ocidentais e orientais o papel feminino esteve relegado ao segundo plano. Tanto a religião quanto a tradição oral tiveram papéis primordiais no aprisionamento do feminino no quarto escuro da História. A teoria da mulher como origem e potência do mal remonta à antiguidade. Muitos historiadores acreditam na existência de sociedades matriarcais que foram desarticuladas pelas sociedades patriarcais. O universo feminino foi, e ainda é na atualidade, um grande enigma para os homens.A presente dissertação tem o objetivo de demonstrar a importância da religião, dos mitos, lendas e contos na construção da figura feminina medieval, para isso, abordaremos como a tradição oral em conjunto com as religiões patriarcais reforçou a ideia da mulher como origem e potência do mal. Recorremos a aspectos históricos, religiosos e literários, procuramos por intermédio de a Bíblia Sagrada e de O Corão entender a influência religiosa, além de verificarmos quais os aspectos históricos que tiveram relevância na perpetuação da misoginia e a ainda como a tradição oral teve a sua cota na construção desse universo misógino. Tentamos compreender como se deu a conexão entre tradição oral e religião na formulação da figura feminina e o porquê dessa mulher ter historicamente uma posição desprivilegiada diante de determinadas culturas

El proceso de deshumanización del morir en la literatura hispánica medieval

354 p.

Hagiografía hispanolatina visigótica y medieval (s. VII-XII)

Coordinador de las actas: Maurilio Pérez González

Las vitae sanctorum de la Hispania medieval: sus manuscritos y su historia editorial

Ejemplar dedicado a: Hagiografía y archivos de la Iglesia santoral hispano-mozárabe en las Diócesis de España. Actas del XVIII Congreso de la Asociación celebrado en Orense (1ª parte) (9 al 13 de septiembre de 2002).

Tradición e innovaciones en la comentarística medieval y del Renacimiento

[ES] Cada vez son más habituales las voces que intentan amortiguar las estridencias contrastivas entre Edad Media y Renacimiento, sobre todo cuando en lo menudo de una actividad tan elemental como la gramatical del comentario de textos la estabilidad de las contundentes antítesis resulta difícil asegurarla. Apoyándose en textos representativos del pensamiento tanto teórico como práctico al respecto de la declaración de autores, el autor del presente artículo prefiere alinearse con los que de un tiempo a esta parte intentan conciliar matizadamente las divergencias -alegorización/historicidad; historicidad/clasicidad- aun dentro del mismo período renacentista. Sin desatender la enorme lección de los humanistas sobre lo que debe ser una cabal filología, concebida no como conocimiento autosuficiente, sino como ámbito privilegiado desde donde confluir con infinidad de otros, a mayores el de la vida.

Mathematical models for the prediction of temperature distributions resulting from the discharge of heated water into large bodies of water

Mathematical models for heated water outfalls were developed for three flow regions. Near the source, the subsurface discharge into a stratified ambient water issuing from a row of buoyant jets was solved with the jet interference included in the analysis. The analysis of the flow zone close to and at intermediate distances from a surface buoyant jet was developed for the two-dimensional and axisymmetric cases. Far away from the source, a passive dispersion model was solved for a two dimensional situation taking into consideration the effects of shear current and vertical changes in diffusivity. A significant result from the surface buoyant jet analysis is the ability to predict the onset and location of an internal hydraulic jump. Prediction can be made simply from the knowledge of the source Froude number and a dimensionless surface exchange coefficient. Parametric computer programs of the above models are also developed as a part of this study. This report was submitted in fulfillment of Contract No. 14-12-570 under the sponsorship of the Federal Water Quality Administration.

Small water bodies for sustainable fisheries production

A brief account is given of some of the discussions presented at a workshop regarding reservoir fisheries in Asia held in Hangzhou, China in Oct 1990. The presentations covered the range of reservoir fisheries management options, from basic limnological research and capture fisheries to intensive cage culture. Particular reference is made to the situation in China, describing current techniques used for stocking and developing reservoir fisheries.

Os cavaleiros imaginários de Terry Gilliam: uma análise da transição da figura do cavaleiro medieval da literatura para o cinema

As narrativas em torno da busca do Graal tiveram origem no século XI e foram de grande importância para fixar a imagem de um personagem típico da sociedade medieval, o cavaleiro, como um novo modelo heroico. Nesse sentido, os cavaleiros que encontraram o Graal nessas narrativas, especialmente no ciclo literário conhecido como Matéria da Bretanha, representam a configuração máxima desse paradigma. Esta pesquisa visa analisar a permanência de tal imagem no cinema, que é igualmente uma arte narrativa, como o eram as novelas de cavalaria que originaram o modelo. O corpus a ser analisado são três significativas obras do cineasta norte-americano Terry Gilliam que direta ou indiretamente retomam a questão do Graal: Monty Python em busca do Cálice sagrado (Monty Phyton and The Holy Grail, 1974), O pescador de ilusões (The Fisher King, 1991) e Os doze macacos (Twelve Monkeys, 1995). Assim, procura-se com esta tese traçar um panorama das retomadas da imagem literária e medieval dos cavaleiros no cinema, assim como observar as mudanças no padrão dessas imagens descritas literariamente para sua representação óptico-sonora