965 resultados para Rapports de couples


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Analisa as repercussões sociais e os sucedâneos jurídicos à falta de regulamentação em lei de usos e costumes, já incorporados ao modus vivendi da sociedade, de populações de orientação sexual minoritária. Toma-se como paradigma dessa situação, o Projeto de lei nº 1.151/1995, de autoria da ex-deputada federal Marta Suplicy, que visa a instituir a união civil homossexual, reformada depois para parceria civil registrada entre pessoas do mesmo sexo. Tramitando há mais de 13 anos na Câmara dos Deputados, e aprovado por unanimidade pela Comissão Especial que o analisou, aguarda penosamente a apreciação do Plenário daquela Casa de Leis. Por isso, desamparados em suas demandas, os atores sociais envolvidos buscam outros foros onde possam ser ouvidos.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Newfound attention has been given to solute transport in nanochannels. Because the electric double layer (EDL) thickness is comparable to characteristic channel dimensions, nanochannels have been used to separate ionic species with a constant charge-to-size ratio (i.e., electrophoretic mobility) that otherwise cannot be separated in electroosmotic or pressure- driven flow along microchannels. In nanochannels, the electrical fields within the EDL cause transverse ion distributions and thus yield charge-dependent mean ion speeds in the flow. Surface roughness is usually inevitable during microfabrication of microchannels or nanochannels. Surface roughness is usually inevitable during the fabrication of nanochannels. In the present study, we develop a numerical model to investigate the transport of charged solutes in nanochannels with hundreds of roughness-like structures. The model is based on continuum theory that couples Navier-Stokes equations for flows, Poisson-Boltzmann equation for electrical fields, and Nernst-Planck equation for solute transports. Different operating conditions are considered and the solute transport patterns in rough channels are compared with those in smooth channels. Results indicate that solutes move slower in rough nanochannels than in smooth ones for both pressure- driven and electroosmotic flows. Moreover, solute separation can be significantly improved by surface roughness under certain circumstances.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A new transition prediction model is introduced, which couples the intermittency effect into the turbulence transport equations and takes the characteristics of fluid transition into consideration to mimic the exact process of transition. Test cases include a two-dimensional incompressible plate and a two-dimensional NACA0012 airfoil. Performance of this transition model for incompressible flows is studied, with numerical results consistent to experimental data. The requirement of grid resolution for this transition model is also studied.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A novel spectroscopy of trapped ions is proposed which will bring single-ion detection sensitivity to the observation of magnetic resonance spectra. The approaches developed here are aimed at resolving one of the fundamental problems of molecular spectroscopy, the apparent incompatibility in existing techniques between high information content (and therefore good species discrimination) and high sensitivity. Methods for studying both electron spin resonance (ESR) and nuclear magnetic resonance (NMR) are designed. They assume established methods for trapping ions in high magnetic field and observing the trapping frequencies with high resolution (<1 Hz) and sensitivity (single ion) by electrical means. The introduction of a magnetic bottle field gradient couples the spin and spatial motions together and leads to a small spin-dependent force on the ion, which has been exploited by Dehmelt to observe directly the perturbation of the ground-state electron's axial frequency by its spin magnetic moment.

A series of fundamental innovations is described m order to extend magnetic resonance to the higher masses of molecular ions (100 amu = 2x 10^5 electron masses) and smaller magnetic moments (nuclear moments = 10^(-3) of the electron moment). First, it is demonstrated how time-domain trapping frequency observations before and after magnetic resonance can be used to make cooling of the particle to its ground state unnecessary. Second, adiabatic cycling of the magnetic bottle off between detection periods is shown to be practical and to allow high-resolution magnetic resonance to be encoded pointwise as the presence or absence of trapping frequency shifts. Third, methods of inducing spindependent work on the ion orbits with magnetic field gradients and Larmor frequency irradiation are proposed which greatly amplify the attainable shifts in trapping frequency.

The dissertation explores the basic concepts behind ion trapping, adopting a variety of classical, semiclassical, numerical, and quantum mechanical approaches to derive spin-dependent effects, design experimental sequences, and corroborate results from one approach with those from another. The first proposal presented builds on Dehmelt's experiment by combining a "before and after" detection sequence with novel signal processing to reveal ESR spectra. A more powerful technique for ESR is then designed which uses axially synchronized spin transitions to perform spin-dependent work in the presence of a magnetic bottle, which also converts axial amplitude changes into cyclotron frequency shifts. A third use of the magnetic bottle is to selectively trap ions with small initial kinetic energy. A dechirping algorithm corrects for undesired frequency shifts associated with damping by the measurement process.

The most general approach presented is spin-locked internally resonant ion cyclotron excitation, a true continuous Stern-Gerlach effect. A magnetic field gradient modulated at both the Larmor and cyclotron frequencies is devised which leads to cyclotron acceleration proportional to the transverse magnetic moment of a coherent state of the particle and radiation field. A preferred method of using this to observe NMR as an axial frequency shift is described in detail. In the course of this derivation, a new quantum mechanical description of ion cyclotron resonance is presented which is easily combined with spin degrees of freedom to provide a full description of the proposals.

Practical, technical, and experimental issues surrounding the feasibility of the proposals are addressed throughout the dissertation. Numerical ion trajectory simulations and analytical models are used to predict the effectiveness of the new designs as well as their sensitivity and resolution. These checks on the methods proposed provide convincing evidence of their promise in extending the wealth of magnetic resonance information to the study of collisionless ions via single-ion spectroscopy.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

While concentrator photovoltaic cells have shown significant improvements in efficiency in the past ten years, once these cells are integrated into concentrating optics, connected to a power conditioning system and deployed in the field, the overall module efficiency drops to only 34 to 36%. This efficiency is impressive compared to conventional flat plate modules, but it is far short of the theoretical limits for solar energy conversion. Designing a system capable of achieving ultra high efficiency of 50% or greater cannot be achieved by refinement and iteration of current design approaches.

This thesis takes a systems approach to designing a photovoltaic system capable of 50% efficient performance using conventional diode-based solar cells. The effort began with an exploration of the limiting efficiency of spectrum splitting ensembles with 2 to 20 sub cells in different electrical configurations. Incorporating realistic non-ideal performance with the computationally simple detailed balance approach resulted in practical limits that are useful to identify specific cell performance requirements. This effort quantified the relative benefit of additional cells and concentration for system efficiency, which will help in designing practical optical systems.

Efforts to improve the quality of the solar cells themselves focused on the development of tunable lattice constant epitaxial templates. Initially intended to enable lattice matched multijunction solar cells, these templates would enable increased flexibility in band gap selection for spectrum splitting ensembles and enhanced radiative quality relative to metamorphic growth. The III-V material family is commonly used for multijunction solar cells both for its high radiative quality and for the ease of integrating multiple band gaps into one monolithic growth. The band gap flexibility is limited by the lattice constant of available growth templates. The virtual substrate consists of a thin III-V film with the desired lattice constant. The film is grown strained on an available wafer substrate, but the thickness is below the dislocation nucleation threshold. By removing the film from the growth substrate, allowing the strain to relax elastically, and bonding it to a supportive handle, a template with the desired lattice constant is formed. Experimental efforts towards this structure and initial proof of concept are presented.

Cells with high radiative quality present the opportunity to recover a large amount of their radiative losses if they are incorporated in an ensemble that couples emission from one cell to another. This effect is well known, but has been explored previously in the context of sub cells that independently operate at their maximum power point. This analysis explicitly accounts for the system interaction and identifies ways to enhance overall performance by operating some cells in an ensemble at voltages that reduce the power converted in the individual cell. Series connected multijunctions, which by their nature facilitate strong optical coupling between sub-cells, are reoptimized with substantial performance benefit.

Photovoltaic efficiency is usually measured relative to a standard incident spectrum to allow comparison between systems. Deployed in the field systems may differ in energy production due to sensitivity to changes in the spectrum. The series connection constraint in particular causes system efficiency to decrease as the incident spectrum deviates from the standard spectral composition. This thesis performs a case study comparing performance of systems over a year at a particular location to identify the energy production penalty caused by series connection relative to independent electrical connection.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The electrochemical and electrocatalytic behavior of a series of heteropolytungstate anions in which a tungsten atom in the well known Keggin structure has been replaced by an iron atom is described. All of the iron substituted ions exhibit a one electron reversible couple associated with the Fe3+ center and a pair of two electron waves attributed to electron addition and removal from the tungsten oxo framework. The pH and ionic strength effects upon the various electrochemical processes are discussed and interpreted in terms of a competition between protonation and ion pairing of the highly negatively charged ions.

The anions are efficient catalysts for the electroreduction of hydrogen peroxide. A catalytic mechanism involving a formally Fe(IV) intermediate is proposed. Pulse radiolysis experiments were employed to detect the intermediate and evaluate the rate constants for the reactions in which it is formed and decomposed. A chain mechanism for the catalytic decomposition of hydrogen peroxide in which the Fe center shuttles between the +2, +3, and +4 oxidation states is proposed to explain the non-integral stoichiometry observed for the iron substituted polytungstate catalyzed electroreduction of hydrogen peroxide.

The anions are also efficient electrocatalyst for the electrochemical conversion of nitric oxide to ammonia. The catalyzed reduction does not produce hydroxylamine as an intermediate and appears to depend upon the ability of the multiply reduced heteropolytungstates to deliver several electrons to the bound NO group in a concerted step. A valuable feature of the heteropolytungstates is the ease at which the formal potentials of the several redox couples they exhibit may be shifted by changing the identity of the central heteroatom. Exploitation of this feature provided diagnostic information that was decisive in establishing the mechanism of electrocatalytic reduction.

The iron substituted heteropolytungstates are not degraded by repeated cycling between their oxidized and reduced states. They also show superior activity compared to their unsubstituted analogues, indicating that the Fe center acts as a binding site that facilitates inner-sphere electron transfer processes. The basic electrochemistry of several other transition metal substituted Keggin ions is also described.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

This work reports investigations upon weakly superconducting proximity effect bridges. These bridges, which exhibit the Josephson effects, are produced by bisecting a superconductor with a short (<1µ) region of material whose superconducting transition temperature is below that of the adjacent superconductors. These bridges are fabricated from layered refractory metal thin films whose transition temperature will depend upon the thickness ratio of the materials involved. The thickness ratio is changed in the area of the bridge to lower its transition temperature. This is done through novel photolithographic techniques described in the text, Chapter 2.

If two such proximity effect bridges are connected in parallel, they form a quantum interferometer. The maximum zero voltage current through this circuit is periodically modulated by the magnetic flux through the circuit. At a constant bias current, the modulation of the critical current produces a modulation in the dc voltage across the bridge. This change in dc voltage has been found to be the result of a change in the internal dissipation in the device. A simple model using lumped circuit theory and treating the bridges as quantum oscillators of frequency ω = 2eV/h, where V is the time average voltage across the device, has been found to adequately describe the observed voltage modulation.

The quantum interferometers have been converted to a galvanometer through the inclusion of an integral thin film current path which couples magnetic flux through the interferometer. Thus a change in signal current produces a change in the voltage across the interferometer at a constant bias current. This work is described in Chapter 3 of the text.

The sensitivity of any device incorporating proximity effect bridges will ultimately be determined by the fluctuations in their electrical parameters. He have measured the spectral power density of the voltage fluctuations in proximity effect bridges using a room temperature electronics and a liquid helium temperature transformer to match the very low (~ 0.1 Ω) impedances characteristic of these devices.

We find the voltage noise to agree quite well with that predicted by phonon noise in the normal conduction through the bridge plus a contribution from the superconducting pair current through the bridge which is proportional to the ratios of this current to the time average voltage across the bridge. The total voltage fluctuations are given by <V^2(f ) > = 4kTR^2_d I/V where R_d is the dynamic resistance, I the total current, and V the voltage across the bridge . An additional noise source appears with a strong 1/f^(n) dependence , 1.5 < n < 2, if the bridges are fabricated upon a glass substrate. This excess noise, attributed to thermodynamic temperature fluctuations in the volume of the bridge, increases dramatically on a glass substrate due to the greatly diminished thermal diffusivity of the glass as compared to sapphire.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Esta tese tem como objeto a regulação política da sexualidade no âmbito da família por saberes e instituições médicas brasileiras (1838-1940). Orienta-se pelo interesse em analisar continuidades e descontinuidades na construção de objetos, estratégias e táticas políticas direcionados para a regulação higiênica e eugênica do casamento e da sexualidade infantil. De inspiração foucaultiana, inscreve-se no campo da história dos saberes e está subsidiada por um conjunto heterogêneo de documentos (teses, artigos de periódicos, livros, anais etc.) circunscritos, majoritariamente, ao campo da medicina. Analisa a constituição de uma defesa higiênica dos casamentos no pensamento médico novecentista, voltada para remanejamentos das figuras de esposa e marido na nova configuração de família que começava a se esboçar no Brasil, contrastando-a com a regulação católica da moral sexual colonial. Em seguida, descreve a visibilidade higiênica que a medicina dará a infância no século XIX, problematizando especificamente o interesse pelo tema da masturbação, que articula simultaneamente a família, centrada na figura da mãe, e a escola na convocação de zelar pela criança. Partindo das contradições sociais que se apresentaram na construção do projeto liberal nacional a partir da década de 1870, discute a apropriação do discurso da degenerescência pelo saber médico-psiquiátrico brasileiro, que propiciou uma leitura da brasilidade marcada pelo excesso sexual e pela condição degenerada da miscigenação, a fim de pensar as condições de possibilidade para a emergência do projeto de eugenia matrimonial institucionalizado nas primeiras décadas do século XX e toma como táticas a campanha pela compulsoriedade do exame pré-nupcial, o combate aos casamentos consanguíneos, o controle do contágio venéreo e o aconselhamento sexual dos casais. Analisa a campanha de educação sexual, cuja pretensão de instituir uma sciencia sexual no Brasil, de legitimidade controversa, tinha como horizonte viabilizar uma profilaxia sexual que mitigasse a produção da criminalidade, das perversões sexuais e das doenças nervosas, bem como os desajustes familiares, a partir da fabricação de um novo objeto, qual seja, a sexualidade infantil, no qual incidirá uma nova pedagogia. Nesse particular, aponta particularidades discursivas da difusão das idéias freudianas entre higienistas brasileiros. Finalmente, sinaliza a constituição da higiene mental da criança como um novo domínio para a psiquiatria brasileira, que tomou a intensa circulação afetiva intrafamiliar como ponto de ancoragem para um projeto de normalização social, ainda centrado na eugenia, mas já atravessado por uma psicologia da adaptação.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

An analytic technique is developed that couples to finite difference calculations to extend the results to arbitrary distance. Finite differences and the analytic result, a boundary integral called two-dimensional Kirchhoff, are applied to simple models and three seismological problems dealing with data. The simple models include a thorough investigation of the seismologic effects of a deep continental basin. The first problem is explosions at Yucca Flat, in the Nevada test site. By modeling both near-field strong-motion records and teleseismic P-waves simultaneously, it is shown that scattered surface waves are responsible for teleseismic complexity. The second problem deals with explosions at Amchitka Island, Alaska. The near-field seismograms are investigated using a variety of complex structures and sources. The third problem involves regional seismograms of Imperial Valley, California earthquakes recorded at Pasadena, California. The data are shown to contain evidence of deterministic structure, but lack of more direct measurements of the structure and possible three-dimensional effects make two-dimensional modeling of these data difficult.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

O tema da exclusão social sempre esteve presente na Literatura Brasileira, porém, na virada do século XX para o XXI, ele ganha ainda mais relevo, através de narrativas realistas, chocantes, exacerbadas de violência e até anomia, que enfatizam a imagem dos excluídos. Cidade de Deus (Paulo Lins: 1997) e Meu nome não é Johnny (Guilherme Fiuza: 2004) focalizam a exclusão dos envolvidos com o narcotráfico. A despeito das diferenças entre as duas narrativas, os seus protagonistas entram em ação a partir da marginalidade; ganham autonomia, no cenário urbano, através da criminalidade, e se tornam ameaçadoramente visíveis, depois de uma histórica invisibilidade. O estudo das complexidades concernentes ao tratamento ficcional do tema se distribuiu, nessa dissertação, em três capítulos. No primeiro capítulo, as obras foram estudadas individualmente, em função da organização dos relatos no espaço narrativo. O segundo capítulo abordou a correlação entre geografia cultural e teoria da literatura, em suas considerações sobre a proeminência da categoria do espaço para o trabalho narratológico. Nessa perspectiva interdisciplinar, foram analisadas as paisagens ficcionais de ambos os romances e, em seguida, articulou-se o roteiro ficcional de cada romance com o pensamento de Foucault sobre os lugares heterotópicos. No terceiro capítulo, intertextualizando o binômio disciplinar geografia cultural e literatura com a filosofia, retroagiu-se aos filósofos idealistas alemães que teorizaram sobre o trágico e intuíram que a tragicidade não se manifesta apenas na tragédia, mas também em obras que lidam com a experiência do irrepresentável, da representação negativa e, em termos estéticos, do sublime. Conjugando as idéias de Hölderlin sobre o vislumbre do divino, de Schopenhauer sobre a metafísica da música, e de Nietzsche sobre a correlação entre o apolíneo e o dionisíaco, tragédia e música, chegou-se à conclusão de que ambas as narrativas incorporam produtivamente ao projeto ficcional duas metáforas absolutas (Hans Blumenberg) que dizem respeito à exclusão/inclusão: a cidade e o hipocorístico (Johnny), dois espaços um material, outro alegórico interativos, em ambos os romances. Em Meu nome não é Johnny, o percurso simbólico do protagonista o leva do sofrimento à redenção social e à inclusão (grandemente graças à atividade musical); em Cidade de Deus, a brutalização progressiva das relações humanas leva à erradicação de qualquer manifestação da sensibilidade, a uma cidade sem música e à permanência da exclusão

Relevância:

10.00% 10.00%

Publicador:

Resumo:

A quantitative study has been performed on the stability of GaAs surfaces in a 0.10 M K2Se-0.01 M K2Se2 aqueous solution. In this electrolyte, n-type GaAs electrodes displayed significant photocorrosion in competition with faradaic charge transfer to Se2-. Chemisorption of group VIIIB metal ions onto the GaAs surfaces yielded improved current-voltage behavior of the GaAs photoanodes, and also resulted in a significant reduction in photocorrosion. This behavior implies that the chemisorbed metal ions act to increase the rate of hole transfer to the Se2- species. Related experiments on n-GaAs, pGaAs, and Sn-doped In2O3 electrodes in Te2-/- aqueous solutions have also been performed.

The majority carrier (electrons) transfer rate constant at a highly doped n+-Si/Co(Cp)2Cl-methanol junction has been measured directly using the chronoamperometry electrochemical technique. The reduction reaction rate of Co(Cp)2+ was 0.03 cm-s-1 at the Si electrode, and was more than 100 times slower than at a hanging mercury electrode. The slower rate was attributed to the smaller optical and static dielectric constants, and the lower density of electrons of the semiconductor. The experimental results were compared to the Marcus theory of charge transfer.

The unique properties of high purity Si/liquid junctions have been investigated under illumination conditions in which the photogenerated carrier concentration exceeds the dopant concentration. Under these high injection conditions, negligible electric fields exist at the semiconductor/liquid interface, and carrier motion is driven by diffusion. Studies of the current-voltage properties of the Si in methanol solutions containing various redox couples suggested that high efficiency photoelectrochemical cells could be established through selective collection of carriers at the semiconductor/liquid junction. The quasi-Fermi levels of electrons and holes were measured directly against the solution potential. Steady-state and transient photovoltage measurements, and theoretical modeliug of the carrier transport, generation, and recombination dynamics indicated that the quasi-Fermi levels were flat across the semiconductor sample. The recombination velocities at the Si/liquid junctions have also been measured, and were shown to vary with the solution potential following the Shockley-Read-Hall theory on recombination.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Verifica-se, no correr da história da filosofia, dois sentidos próximos, mas divergentes, no emprego da expressão senso comum. Propõe-se a designação de senso comum natural para um e a de senso comum cultural para o outro, designações estas que unificam razoavelmente, dentro de suas próprias vertentes, os conceitos de senso comum e às quais corresponde algo de concreto, segundo definições estritas. A partir dessas definições, estuda-se o relacionamento entre a filosofia e o senso comum, procurando estabelecer até que ponto se trata de uma relação de antagonismo ou de dependência, na busca de um conhecimento que possa ser tido por verdadeiro.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Considerado pela maioria da crítica como uma literatura pútrida (cf. ULBACH, 1868) ou torpe (cf. VERÍSSIMO, 1894), acusado de confundir ingenuamente ciência e literatura, bem como de cientizar a linguagem literária, e em particular no Brasil, além disso, questionado por plágio ou importação de uma moda estrangeira, o naturalismo foi relegado às margens da historiografia literária. Assumindo como ponto de partida esse panorama crítico, a tese propõe uma reavaliação crítica e historiográfica da estética naturalista, começando por descrever e analisar sua origem no decurso da história, a partir do advento do realismo moderno nas obras de Stendhal e de Balzac (cf. AUERBACH, 2004). Enfoca a lenta afirmação dos termos realismo e naturalismo, bem como a importância da contribuição de diferentes romancistas franceses no processo de consolidação da estética realista e de seu prolongamento no naturalismo. Discute-se também o projeto estético proposto por Zola, assim como se desconstroem mitos corroborados pela historiografia literária a respeito da teoria e do movimento naturalistas. Por fim, correlacionando a estética naturalista com o ideal republicano, aborda-se a aclimatação dos princípios naturalistas no Brasil, na obra daquele que foi seu principal representante, Aluísio Azevedo. A partir de uma abordagem comparativa entre o naturalismo na França e no Brasil, busca-se, em síntese, contribuir para o processo de revisão crítica e historiográfica de um período literário muito produtivo nos dois países, não obstante a tendência para sua desvalorização em geral observada nas manifestações da crítica novecentista

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Esta tese baseia-se em trabalho etnográfico que investiga performances de gênero em um Clube de Mulheres no Rio de Janeiro, onde, após um show de strip-tease masculino para uma platéia exclusivamente feminina, tem início uma festa dançante com a presença de público masculino. No espetáculo são encenados atos (hetero)sexuais em duplas ou em grupo, envolvendo os strippers e as mulheres que voluntariamente sobem ao palco. A trilha sonora, marcada pelo estilo pornofunk, traz elementos alusivos à infidelidade conjugal masculina e feminina, à orgia e à prostituição masculina e feminina. Como em rituais de inversão, há, durante o show, tanto uma suspensão controlada das convenções de gênero tradicionais, quanto sua paradoxal reafirmação. Para o deleite de um público feminino, os strippers mantêm no palco a representação do papel ativo na cópula, e tanto sua hexis corporal quanto suas performances realçam a prontidão para o ato sexual, a virilidade e o controle sobre a conduta feminina. As mulheres, por sua vez, encenam uma parcial submissão ao controle masculino. Elas manifestam alguma reatividade e heteronomia em relação aos homens na festa que acontece depois, quando pares heterossexuais relativamente anônimos interagem através de aproximações sucessivas que englobam carícias e beijos na boca. Neste contexto, como sujeitos ou objetos, tanto os strippers quanto as mulheres desempenham posições conflitantes com as tradicionais expectativas de gênero, que permanecem, entretanto, preservadas em grande medida pela idéia de que elas dependem de estímulos especiais para, no campo do erotismo e da sexualidade, desejar ou fazer coisas para as quais os homens estariam supostamente sempre prontos. A tese procura mostrar que, como espécie de preço a pagar pelas inversões que ocorrem nesse espaço, tanto a imagem das mulheres quanto a dos strippers é desvalorizada, recaindo sobre eles os estigmas que ainda cercam as rupturas relativas às convenções de gênero.