966 resultados para Schur-Cohn criterion
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La dependencia energética de las redes hidráulicas para su explotación hace que, a lo largo de los años, sus costos variables lleguen a ensombrecer los costos de construcción o costos fijos. El objetivo de este artículo es la minimización de los costos de explotación en redes ramificadas simples ya existentes y estudia la aplicación de las técnicas de sectorización, junto con el uso de variadores de velocidad, como medida de eficiencia energética. Se sugiere un criterio para determinar bajo qué circunstancias resulta favorable aplicar la sectorización. Se aplica en un caso de estudio real: una red simple ramificada existente con cuatro zonas hidráulicas usada para regadío en la provincia de Segovia, España, resultando en un ahorro energético de un 7.52%, pudiéndose llegar hasta un 26.31%, ampliando la franja horaria del bombeo inicial.
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A coupled elastoplastic-damage constitutive model with Lode angle dependent failure criterion for high strain and ballistic applications is presented. A Lode angle dependent function is added to the equivalent plastic strain to failure definition of the Johnson–Cook failure criterion. The weakening in the elastic law and in the Johnson–Cook-like constitutive relation implicitly introduces the Lode angle dependency in the elastoplastic behaviour. The material model is calibrated for precipitation hardened Inconel 718 nickel-base superalloy. The combination of a Lode angle dependent failure criterion with weakened constitutive equations is proven to predict fracture patterns of the mechanical tests performed and provide reliable results. Additionally, the mesh size dependency on the prediction of the fracture patterns was studied, showing that was crucial to predict such patterns
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Highlights of this paper: a method for calculating the ultimate bearing capacity at the tip of a pile is presented; ultimate bearing capacity is generalized for the modified Hoek–Brown criterion; perfect plasticity, isotropy, weightless rock media, without inertial forces, Meyerhof׳s hypothesis are considered; all the formulation can be programmed in a spreadsheet.
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Phase thermodynamics is often perceived as a difficult subject that many students never become fully comfortable with. The Gibbsian geometrical framework can help students to gain a better understanding of phase equilibria. An exercise to interpret the vapor-liquid equilibrium of a binary azeotropic mixture, using the equilibrium condition based on the common tangent plane criterion (the Gibbs stability test), is presented in this paper. From a T-composition phase diagram for the mixture, the temperature is set at different values: above, intermediate to, and below the boiling temperatures of the pure components, to intersect different regions of the system. Students prepare an Excel spreadsheet where the Gibbs energy of mixing of the vapor and liquid mixtures are calculated and represented over the whole range of compositions and then, apply the Gibbs stability test to ascertain the aggregation state of the system and to calculate the VL phase equilibrium compositions. Finally, Matlab is used to generate the 3D Gibbs energy of mixing surfaces for both phases over the whole range of temperatures which facilitates the geometrical interpretation of the vapor-liquid equilibrium.
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No abstract.
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"The project reported herein was performed pursuant to a grant from the U.S. Office of Education, Department of Health, Education and Welfare."
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Texas Department of Transportation, Austin
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National Highway Traffic Safety Administration, Washington, D.C.
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Mode of access: Internet.
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"Contract no. DA-30-069-ORD-3443. ARPA order no. 253-62."
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Mode of access: Internet.
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Mode of access: Internet.