A Linear Stability Analysis Of Large-Prandtl-Number Thermocapillary Liquid Bridges

A linear stability analysis is applied to determine the onset of oscillatory thermocapillary convection in cylindrical liquid bridges of large Prandtl numbers (4 <= Pr <= 50). We focus on the relationships between the critical Reynolds number Re-c, the azimuthal wave number m, the aspect ratio F and the Prandtl number Pr. A detailed Re-c-Pr stability diagram is given for liquid bridges with various Gamma. In the region of Pr > 1, which has been less studied previously and where Re, has been usually believed to decrease with the increase of Pr, we found Re-c exhibits an early increase for liquid bridges with Gamma around one. From the computed surface temperature gradient, it is concluded that the boundary layers developed at both solid ends of liquid bridges strengthen the stability of basic axisymmetric thermocapillary convection at large Prandtl number, and that the stability property of the basic flow is determined by the "effective" part of liquid bridge. (c) 2008 Published by Elsevier Ltd on behalf of COSPAR.

Hydrothermal Instability Of Thermocapillary Convection In Large-Prandtl-Number Liquid Bridges Under Microgravity

Linear stability analysis was performed to study the mechanism of transition of thermocapillary convection in liquid bridges with liquid volume ratios ranging from 0.4 to 1.2, aspect ratio of 0.75 and Prandtl number of 100. 2-D governing equations were solved to obtain the steady axi-symmetric basic flow and temperature distributions. 3-D perturbation equations were discretized at the collocation grid points using the Chebyshev-collocation method. Eigenvalues and eigenfunctions were obtained by using the Q-R. method. The predicted critical Marangoni numbers and critical frequencies were compared with data from space experiments. The disturbance of the temperature distribution on the free surface causes the onset of oscillatory convection. It is shown that the origin of instability is related to the hydrothermal origin for convections in large-Prandtl-number liquid bridges. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved.

Sapientia, 1956, Vol. XI, nº 41 (número completo)

Contenido: Filosofía y Teología en el tomismo / La Dirección – Gérmenes de idealismo en las “Investigaciones lógicas” de Husserl / Juan A. Casaubón – La materia inteligible / Emilio Mondelli – El estoicismo y su teoría del hombre / Benito R. Raffo Magnasco -- Bibliografía

Letras, 1999-2000, nº 40-41 (número completo)

Contenido: Nota preliminar – Poesía mariana en Gonzalo de Berceo / Lía N. Uriarte Rebaudi – El judío y el diablo como “otro” en los Milagros de Nuestra Señora de Berceo / Heanon M. Wilkins – “Intellectum tibi dabo et instruam te” / Eric Naylor – Descripción, narración, argumentación y crisis de la oralidad en el Libro del Buen Amor / Sofía M. Carrizo Rueda – El poema de Alfonso XI: ¿Un eco priscilianista, sabeliano, patripasiano? / Jorge Norberto Ferro – El vino en el refranero español; concordancias / Dolly M. Lucero Ontiveros – Una propuesta de clasificación de la Literatura Sapiencial Hispánica en el siglo XIII / Alicia E. Ramadori – Fray Juan García de Castrojeriz receptor de Aristóteles / Hugo Oscar Bizzarri – La especificidad de la prosa alfonsí; el caso del Lapidario / Mirta G. Aguayo – Alfonso el Sabio y Brunetto Latini: convergencias / Gretchem Arnstedt de Magneres – La figura autoral de Alfonso X en las Cantigas de Santa María / Santiago Aníbal Disalvo – La historia del rey Guillermo de Inglaterra: del relato del siglo XIV a la crónica quinientista / Carina Alejandra Zubillaga – El prólogo de “El Victorial”: heterogeneidad y orden a favor de una adecuada recepción / María Mercedes Rodríguez Temperley – A propósito del prólogo de la Confesión del amante / María Cristina Balestrini – Función de la “ekprhasis” en los relatos caballerescos / Lilia Elda Ferrario de Orduna – Una nueva fuente del Amadís de Gaula primitivo: la Waltbarii poesis del abad Ekkehard I. de Saint Gall / Aquilino Suárez Pallasá – Profecía mesiánica y profecía apocalíptica: la cuestión constantinopolitana en las Sergas de Esplandián y Primaleón / Javier Roberto González – Dos romances sefardíes de incógnito en una colección de romances. Aporte de nuevas versiones / Eleonora Angélica Alberti de Kleinbort – Conjeturas acerca del original manuscrito de la Comedia de Fernando Rojas / Germán Orduna – Fernando de Rojas, ¿autor? / Joseph Thomas Snow – El fondo medieval de la colección Foulché-Delbosc / Georgina Olivetto – Nómina de todos los congresistas

Basic equations for suspension flows with interphase mass-transfer

In the case of suspension flows, the rate of interphase momentum transfer M(k) and that of interphase energy transfer E(k), which were expressed as a sum of infinite discontinuities by Ishii, have been reduced to the sum of several terms which have concise physical significance. M(k) is composed of the following terms: (i) the momentum carried by the interphase mass transfer; (ii) the interphase drag force due to the relative motion between phases; (iii) the interphase force produced by the concentration gradient of the dispersed phase in a pressure field. And E(k) is composed of the following four terms, that is, the energy carried by the interphase mass transfer, the work produced by the interphase forces of the second and third parts above, and the heat transfer between phases. It is concluded from the results that (i) the term, (-alpha-k-nabla-p), which is related to the pressure gradient in the momentum equation, can be derived from the basic conservation laws without introducing the "shared-pressure presumption"; (ii) the mean velocity of the action point of the interphase drag is the mean velocity of the interface displacement, upsilonBAR-i. It is approximately equal to the mean velocity of the dispersed phase, upsilonBAR-d. Hence the work terms produced by the drag forces are f(dc) . upsilonBAR-d, and f(cd) . upsilonBAR-d, respectively, with upsilonBAR-i not being replaced by the mean velocity of the continuous phase, upsilonBAR-c; (iii) by analogy, the terms of the momentum transfer due to phase change are upsilonBAR-d-GAMMA-c, and upsilonBAR-d-GAMMA-d, respectively; (iv) since the transformation between explicit heat and latent heat occurs in the process of phase change, the algebraic sum of the heat transfer between phases is not equal to zero. Q(ic) and Q(id) are composed of the explicit heat and latent heat, so that the sum Q(ic) + Q(id)) is equal to zero.

The dynamical process of a coronal transient associated with an eruptive prominence .1. Basic mechanism

The statistical correlation between an eruptive prominence and the coronal transient associated with this prominence implies that there should be a relationship between these two kinds of dynamical processes. This paper analyzes the dynamical effect of a plasma

Visual Basic在油藏数值模拟中的应用

随着油藏数值模拟技术的发展以及油藏数值模拟软件的不断改进和完善,油藏数值模拟软件在油田开发中的应用越来越广泛。对油藏数值模拟软件计算出的数据进行整理不仅枯燥而且花费了大量时间。本文利用Visual Basic语言编制了处理ECLIPSE软件生成的油气田开发指标数据软件(RSMAN)。该软件方便了油气田开发指标的整理和汇总,软件界面友好,操作简单。

A atuação organizada do setor bancário e a regulamentação das tarifas bancárias

Analisa a questão do pressuposto da necessidade de regulação do sistema bancário e o lobby, como parte legítima do processo decisório político. Estas variáveis são fundamentais para a compreensão do estudo da atuação dos grupos de interesse envolvidos no processo de aprovação, pelo Conselho Monetário Nacional, da Resolução 3.518, de 06/12/07, que trata da tarifa bancária. A análise da regulamentação do setor bancário procura evidenciar os fatores que influenciam a escolha, por parte do órgão regulador, do grau de controle a ser exercido sobre as instituições financeiras, podendo ser enfatizado o caráter prudencial, fiscalizador ou liberal das normas bancárias, conforme política posta em prática pelo Banco Central. A abordagem acerca do lobbying evidencia a legitimidade de sua prática junto aos órgãos públicos, como também a possibilidade de sua regulamentação no Brasil. Em seguida, é analisado o comportamento da tarifa bancária antes, durante e depois da publicação da Resolução em questão, assim como as audiências públicas que a antecederam, a fim de investigar seus possíveis resultados, pois a partir deles, como também por intermédio das entrevistas concedidas, pode-se depreender a atuação dos grupos de influência na consecução de seus interesses.

The Effect of Data Revisions on the Basic New Keynesian Model

This paper proposes an extended version of the basic New Keynesian monetary (NKM) model which contemplates revision processes of output and inflation data in order to assess the importance of data revisions on the estimated monetary policy rule parameters and the transmission of policy shocks. Our empirical evidence based on a structural econometric approach suggests that although the initial announcements of output and inflation are not rational forecasts of revised output and inflation data, ignoring the presence of non well-behaved revision processes may not be a serious drawback in the analysis of monetary policy in this framework. However, the transmission of inflation-push shocks is largely affected by considering data revisions. The latter being especially true when the nominal stickiness parameter is estimated taking into account data revision processes.

Basic equations for ferroelectrics

A set of new formula of energy functions for ferroelectrics was proposed, and then the new basic equations were derived in this paper. The finite element formulation based on the new basic equations was improved to avoid the equivalent nodal load produced by remnant polarization. With regard to the fundamentals of mathematics and physics, the new energy functions and basic equations are reasonable for the material element of ferroelectrics in finite element analysis.

Influence of seagrass landscape structure on the juvenile blue crab habitat-survival function

Organismal survival in marine habitats is often positively correlated with habitat structural complexity at local (within-patch) spatial scales. Far less is known, however, about how marine habitat structure at the landscape scale influences predation and other ecological processes, and in particular, how these processes are dictated by the interactive effect of habitat structure at local and landscape scales. The relationship between survival and habitat structure can be modeled with the habitat-survival function (HSF), which often takes on linear, hyperbolic, or sigmoid forms. We used tethering experiments to determine how seagrass landscape structure influenced the HSF for juvenile blue crabs Callinectes sapidus Rathbun in Back Sound, North Carolina, USA. Crabs were tethered in artificial seagrass plots of 7 different shoot densities embedded within small (1 – 3 m2) or large (>100 m2) seagrass patches (October 1999), and within 10 × 10 m landscapes containing patchy (<50% cover) or continuous (>90% cover) seagrass (July 2000). Overall, crab survival was higher in small than in large patches, and was higher in patchy than in continuous seagrass. The HSF was hyperbolic in large patches and in continuous seagrass, indicating that at low levels of habitat structure, relatively small increases in structure resulted in substantial increases in juvenile blue crab survival. However, the HSF was linear in small seagrass patches in 1999 and was parabolic in patchy seagrass in 2000. A sigmoid HSF, in which a threshold level of seagrass structure is required for crab survival, was never observed. Patchy seagrass landscapes are valuable refuges for juvenile blue crabs, and the effects of seagrass structural complexity on crab survival can only be fully understood when habitat structure at larger scales is considered.

Playing games with words cultural transfer in David Lynch's Blue Velvet

Eguíluz, Federico; Merino, Raquel; Olsen, Vickie; Pajares, Eterio; Santamaría, José Miguel (eds.)

Automated, objective texture segmentation of multibeam echosounder data - Seafloor survey and substrate maps from James Island to Ozette Lake, Washington Outer Coast

Without knowledge of basic seafloor characteristics, the ability to address any number of critical marine and/or coastal management issues is diminished. For example, management and conservation of essential fish habitat (EFH), a requirement mandated by federally guided fishery management plans (FMPs), requires among other things a description of habitats for federally managed species. Although the list of attributes important to habitat are numerous, the ability to efficiently and effectively describe many, and especially at the scales required, does not exist with the tools currently available. However, several characteristics of seafloor morphology are readily obtainable at multiple scales and can serve as useful descriptors of habitat. Recent advancements in acoustic technology, such as multibeam echosounding (MBES), can provide remote indication of surficial sediment properties such as texture, hardness, or roughness, and further permit highly detailed renderings of seafloor morphology. With acoustic-based surveys providing a relatively efficient method for data acquisition, there exists a need for efficient and reproducible automated segmentation routines to process the data. Using MBES data collected by the Olympic Coast National Marine Sanctuary (OCNMS), and through a contracted seafloor survey, we expanded on the techniques of Cutter et al. (2003) to describe an objective repeatable process that uses parameterized local Fourier histogram (LFH) texture features to automate segmentation of surficial sediments from acoustic imagery using a maximum likelihood decision rule. Sonar signatures and classification performance were evaluated using video imagery obtained from a towed camera sled. Segmented raster images were converted to polygon features and attributed using a hierarchical deep-water marine benthic classification scheme (Greene et al. 1999) for use in a geographical information system (GIS). (PDF contains 41 pages.)