The N-Vortex Problem on a Symmetric Ellipsoid: A Perturbation Approach

We consider the N-vortex problem on a ellipsoid of revolution. Applying standard techniques of classical perturbation theory we construct a sequence of conformal transformations from the ellipsoid into the complex plane. Using these transformations the equations of motion for the N-vortex problem on the ellipsoid are written as a formal series on the eccentricity of the ellipsoid's generating ellipse. First order equations are obtained explicitly. We show numerically that the truncated first order system for the three-vortices system on the symmetric ellipsoid is non-integrable.Comment: 14 pages, 1 figur

Does Openness Imply Greater Vulnerability?

This paper provides an empirical evaluation of external vulnerability using panel data methods for a worldwide sample of countries. Controlling for domestic conditions, the paper examines the growth volatility effects of outcome measures of trade and financial openness as well as four types of foreign shocks: terms of trade changes, trading partners' growth rates, international real interest rate changes, and net regional capital inflows. The paper analyzes the possibility of non-linearities by allowing the growth volatility effects of openness to vary with the general level of economic development and by letting the effects of foreign shocks depend on the degree of trade and financial integration. The results are mixed regarding international integration: while trade opening tends to increase growth volatility, financial opening reduces volatility directly and indirectly by dampening the effects of external shocks.

Smart to improve decision making in the selection process of university faculty system using multivariate statistical

El presente tema de investigación aplicado en la Facultad de Ingeniería de la USAT, brindará respuestas acordes a los requerimientos solicitados. Se observa en lo que se refiere al proceso de selección de personal docente, que los problemas se presentan debido a que el proceso es manual, dándose la situación de agotamiento y de trabajo tedioso en el personal. Se justifica el presente trabajo debido a que la propuesta permitirá lograr una reducción en los tiempos empleados, así mismo los costos de inversión a realizar son bajos comparados con los beneficios que obtendrá la institución, científicamente justificable debido a la propuesta innovadora que contribuye con un sistema inteligente, presenta datos en tiempo real que sirven de alternativas para poder así dar soporte en la toma de decisiones para aprobar o no el contrato de un nuevo docente, sistémicamente es importante porque se tendrá un enfoque holístico y multidisciplinario.Abstract : This theme applied research in the Faculty of Engineering of the USAT will provide responses according to the requirements requested. Observed in regard to the selection of teachers, the problems arise because the process is manual, giving the situation of exhaustion and tedious work on staff. The present work is justified because the proposal will achieve a reduction in the time employees, also investment costs to make are low compared to the benefits you will get the institution, scientifically justifiable due to the innovative approach that contributes to a system intelligent, presents real-time data that serve as alternatives to and support in making decisions to approve or not the contract of a new teacher is systemically important because a holistic, multidisciplinary approach will be taken

Comportamento sísmico de edifícios com paredes resistentes

O presente trabalho aborda a questão do comportamento estrutural de edifícios tridimensionais de betão armado, compostos por pórticos reticulados e paredes resistentes de betão armado, sujeitos à acção sísmica regulamentar. Para o efeito, foram considerados os Eurocódigos estruturais, nomeadamente o Eurocódigo 0, Eurocódigo 1 e Eurocódigo 8. As paredes resistentes situam-se nas zonas destinadas às caixas de escadas/elevadores, formando os núcleos resistentes que, perante a ocorrência de um sismo, garantem a estabilidade estrutural e a capacidade de dissipação de energia da estrutura. A consideração destes núcleos teve por base a prática corrente de considerar a zona da caixa de escadas e elevadores em betão armado. A fim de avaliar a importância da localização destes elementos estruturais, elemento fundamental para a caracterização da resposta dinâmica, foi desenvolvido um estudo paramétrico, fazendo-se variar a disposição do núcleo em planta, obtendo-se estruturas com distribuição simétrica e assimétrica da rigidez em planta. Os edifícios considerados neste trabalho foram modelados com base no programa comercial de cálculo automático SAP 2000. A análise sísmica foi realizada de acordo com o preconizado no Eurocódigo 8, e no respectivo Anexo Nacional (em preparação), nomeadamente em termos da definição da acção. Posteriormente, apresentam-se e discutem-se os resultados obtidos, nomeadamente a relação entre a disposição estrutural dos núcleos resistentes, as propriedades dinâmicas e a distribuição das forças sísmicas pelos vários elementos resistentes. Por fim, apresenta-se uma solução estrutural obtida a partir das configurações anteriores e capaz de ultrapassar o comportamento dinâmico/sísmico tido como menos satisfatório

Autoignition of hydrogen/air mixtures by a thin catalytic wire

The autoignition of the catalytic reaction of hydrogen/air mixtures on thin palladium wires is analyzed in this paper. The reduced heterogeneous kinetics is modeled with a mechanism that includes the dissociative adsorption of both reactants, together with three surface reactions of the Langmuir-Hinshelwood type, and the desorption reaction of the adsorbed product, H2O(s). We show that for the description of the ignition conditions, this mechanism can be simplified to a single overall surface reaction involving the temperature and gas concentrations of the reactants at the surface of the wire. The resulting overall rate for the surface reaction has been tested with existing experimental results, after describing the transport of heat and reactants, by natural convection, in the gas phase for a wide range of Rayleigh numbers. The critical conditions for the catalytic ignition have been deduced using high activation energy asymptotics for the desorption kinetics of the most efficiently adsorbed reactant, H(s)