Análise da abrangência de modelo modificado para mancais curtos com deformação.

Este trabalho apresenta uma discussão sobre o estudo dos efeitos térmicos e elásticos decorrentes da pressão de sustentação presentes nos mancais. Para tanto, propõe-se um modelo matemático baseado nas equações para mancais curtos considerando a região de cavitação e utilizando o princípio da continuidade de massa. Com isto, deduzem-se as equações para o mancal a partir das equações de Reynolds e da energia, aplicando uma solução modificada para a solução de Ocvirk, sendo as equações resolvidas numericamente pelo Método das Diferenças Finitas. Somado o tratamento de mecânica dos fluidos, o trabalho discute dois modelos térmicos de previsão de temperatura média do fluido e sua influência no campo de pressão, apresentando gráficos representativos do campo de pressão e de temperatura, assim como as diferenças e implicações das diferenças. Para o cálculo de deformação da estrutura, utiliza-se um Modelo de Elementos Finitos para uma dada geometria, fazendo-se uma avaliação da variação do campo de pressão e o quanto essa diferença afeta as demais propriedades do fluido. Por fim, com o modelo completo, calcula-se o quanto esse modelamento para mancais curtos se aproxima de soluções para mancais finitos, com base em resultados da literatura, chegando a desvios quase oito vezes menores que os previstos pela literatura. Além disso, pode-se estabelecer a abrangência do modelo, ou seja, prever as condições em que suas propriedades são válidas e podem ser utilizadas para estudos iniciais.

No anticorrelation between cyclotron line energy and X-ray flux in 4U 0115+634

We report on an outburst of the high mass X-ray binary 4U 0115+634 with a pulse period of 3.6 s in 2008 March/April as observed with RXTE and INTEGRAL. During the outburst the neutron star’s luminosity varied by a factor of 10 in the 3–50 keV band. In agreement with earlier work we find evidence of five cyclotron resonance scattering features at ~10.7, 21.8, 35.5, 46.7, and 59.7 keV. Previous work had found an anticorrelation between the fundamental cyclotron line energy and the X-ray flux. We show that this apparent anticorrelation is probably due to the unphysical interplay of parameters of the cyclotron line with the continuum models used previously, e.g., the negative and positive exponent power law (NPEX). For this model, we show that cyclotron line modeling erroneously leads to describing part of the exponential cutoff and the continuum variability, and not the cyclotron lines. When the X-ray continuum is modeled with a simple exponentially cutoff power law modified by a Gaussian emission feature around 10 keV, the correlation between the line energy and the flux vanishes, and the line parameters remain virtually constant over the outburst. We therefore conclude that the previously reported anticorrelation is an artifact of the assumptions adopted in the modeling of the continuum.

Suspended matter on the meridional section in the Laptev Sea in August-September 1991

Suspended matter concentration along a meridian section from the Lena River delta to 78°N (~500 km) at ten stations from the surface to the bottom was studied with weight and optical (light attenuation index) techniques. At seven stations average residence time of suspended matter in surface waters was determined by the disequilibrium 234Th method. Average residence time of suspended matter in other depth intervals was calculated by regression dependence between the 234Th/238U ratio and suspended matter concentration. Differential and integral fluxes of suspended matter in the water column were also calculated. Nepheloid matter dominates in suspended matter composition in surface waters. Calculations indicate that, before being buried on the bottom, solid river run-off is resuspended 2.3 times (aver.). Redistribution of nepheloid suspended matter in the near-bottom layer results in formation of a strongly pronounced depocentre - an area of maximal discharge of solid river run-off within the Laptev Sea.

Introduction to the calculus,

"A revision of the author's A first course in the differential and integral calculus."--Pref.

Introduction to the calculus,

"A revision of the author's A first course in the differential and integral calculus."--Pref.

Numerical quadrature over a rectangular domain in two or more dimensions /

"This work was supported in part by the Office of Naval Research under Contract Nonr-1834(27)."

The Cambridge colloquium, 1916.

Includes bibliographical references.

Encyclopaedia of pure mathematics.

Articles reprinted from Encyclopaedia metropolitana.

Contributions to a theory of summability of trigonometric integrals.

Bibliography: p. 227.

Sur l'équation fonctionnelle de Fredholm et quelques-unes de ses applications.

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Über freie und erzwungene schwingungen; eine einführung in die theorie der linearen integralgleichungen

Available on demand as hard copy or computer file from Cornell University Library.

Leçons sur les fonctions de lignes,

Available on demand as hard copy or computer file from Cornell University Library.

Leçons sur les équations intégrales et les équations intégro-différentielles. Leçons professées à la Faculté des sciences de Rome en 1910

Available on demand as hard copy or computer file from Cornell University Library.

Elementi della teoria delle equazioni integrali lineari.

Available on demand as hard copy or computer file from Cornell University Library.

La théorie des marées et les équations intégrales. ...

Thèse--Univ. de Paris.