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Sample records for expansion con restricciones

  1. Programación con restricciones dinámica

    Directory of Open Access Journals (Sweden)

    Broderick Crawford

    2009-07-01

    La propuesta descrita se inspira en enfoques adaptativos existentes, pero que han sido diseñados con otra orientación, como el caso de la Satisfacción de Restricciones Adaptativas, donde dada una secuencia de algoritmos a utilizar, los malos son detectados y reemplazados por el próximo candidato. Sin embargo, en este trabajo no se pretende cambiar un algoritmo completo, sino para un mismo algoritmo de resolución modificar la estrategia que lo guía en base a la observación del conjunto de indicadores, obtenidos del análisis del mismo proceso de búsqueda que está desempeñando. This paper presents algorithms for solving Constraint Satisfaction Problems (CSPs capable of measure the performance of their process through relevant indicators to enable adaptations (self-adjust. The adaptation options are related to the change of Enumeration Strategy, used when bad performance is detected. Done in this way, to find quickly solutions to different problems, solving one of the limitations on the Enumeration Strategy: “for a given problem, there is a particular strategy that works very well, but limited in the efficient resolution of other problems.” The proposal outlined is based on existing approaches, that have been designed with other orientation, such as Adaptive Constraint Satisfaction (ACS, where given a sequence of algorithms to use, bad ones are detected and replaced by the next candidate. However, this paper is not intended to change a complete algorithm, but for the same algorithm, modify the strategy that guides it based on the observation of the set of indicators obtained from the analysis of the search process that is playing.

  2. Planificación de trayectorias para un robot tipo con restricciones dinámicas

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    Leonardo Solaque Guzmán

    2008-01-01

    Full Text Available Este documento presenta una aproximación a la planificación de caminos óptimos para un sistema con restricciones dinámicas y desplazándose dentro de un espacio libre de obstáculos. Se considera el modelo dinámico del dirigible y un análisis para el planteamiento de modelos simplificados o comúnmente conocidos como modelos de control. Se propone una planificación de la trayectoria desde el punto de vista de la teoría óptima utilizando un modelo de la dinámica de un robot móvil (que se desplaza a velocidad constante y en avance, es decir con restricciones dinámicas como punto de partida para la primera aproximación a los caminos óptimos. Para el suavizado de las trayectorias del dirigible se proponen dos modelos con relajación en la dinámica de la variable de control y finalmente se presenta una simulación de la comparación de los diferentes resultados.

  3. Secuenciación heurística de un proyecto con restricciones temporales

    Directory of Open Access Journals (Sweden)

    Villa Juliá, Mª Fulgencia

    2005-01-01

    Full Text Available El presente trabajo aborda el análisis de un problema real del mantenimiento que una compañía aeronáutica debe practicar sobre una flota de aviones del tipo Boeing-747. En primer lugar analizamos en qué consiste dicho mantenimiento, los elementos que lo definen y los objetivos que se persiguen. A continuación estudiamos sus similitudes y diferencias con el RCPS (Resource Constrained Project Scheduling, un modelo clásico aplicado a este tipo de problemas. Entre estas diferencias se encuentran la existencia de restricciones temporales para la secuenciación de determinadas tareas así como otros tipos especiales de relaciones entre las actividades además de las clásicas de precedencia. Concretamos, finalmente, la metodología a aplicar para abordar el pro-blema planteado.

  4. Manejo de restricciones con funciones de penalidad para la planificación del mantenimiento de locaciones petroleras

    Directory of Open Access Journals (Sweden)

    Jorge Ceferino Valdez

    2014-06-01

    Full Text Available La explotación y transporte de petróleo son actividades muy importantes para el desarrollo económico de la sociedad moderna insdustrial. Sin embargo, estas actividades son generadoras de riesgos que se traducen en contaminaciones que afectan el medio ambiente. Por esta razón, es importante que las empresas petroleras lleven a cabo un correcto mantenimiento de sus locaciones. En casos de planificación de mantenimiento de 100 o más locaciones, PAE es una herramienta que provee un plan de visitas para el mantenimiento, usando un algoritmo evolutivo para producir múltiples soluciones a este problema con restricciones. En este trabajo, se implementa una herramienta de optimización evolutiva aplicando técnicas de manejo de restricciones basadas en funciones de penalidad. Detalles de la implementación, resultados experimentales y beneficios son presentados en este informe.

  5. Determinación de restricciones y posibilidades ambientales para la expansion del transporte de gas natural en Colombia

    Directory of Open Access Journals (Sweden)

    Ángel Sanint Enrique

    2011-11-01

    Full Text Available En la línea de la Evaluación Ambiental Estratégica, EAE, se desarrolló un método para la determinación de restricciones y posibilidades ambientales en proyectos de transporte de gas natural por ductos, basado en el uso de herramientas de análisis territorial aplicadas sobre la plataforma SIG (Sistema de Información Geográfica, incorporando criterios ambientales que a escala 1:500.000 apoyarán la toma de decisiones en el nivel de planeación y propiciarán la elaboración del plan de expansión para el transporte de gas natural en Colombia. Para esto, se definió el concepto de ambiente a partir de un Modelo Analítico preexistente; se delimitó un área con posibilidades para la expansión de la red de transporte de gas natural incorporando nuevos trazados; se seleccionaron las variables y factores que complementaban el Modelo Analítico; se definió la estructura de preferencias a partir de una encuesta a expertos; se determinaron las restricciones nacionales y se construyeron superficies numéricas síntesis de critici dad ambiental para cada dimensión. Como resultado, se obtuvieron 5 superficies síntesis, una por cada dimensión, y una superficie final para Colombia, con restricciones y posibilidades ambientales. Además se propusieron análisis complementarios para establecer prioridades en la gestión ambiental.

  6. Epistemic and doxastic logic with restrictions Lógicas epistémica y doxástica con restricciones

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    Manuel Sierra A

    2010-12-01

    Full Text Available Are presented as extensions of classical propositional calculus hierarchies of deductive systems LDR–n and LER–n with n > 1. LER–n is the epistemic logic with restrictions, LDR–n is the doxastic logic with restrictions. The systems LER–1 and LDR–1 are the classical propositional calculus. System LER–(n + 1 can be seen as the result of applying the rule: if X is theorem of LER–n then +X is theorem of LER–(n + 1. Systems also restricts the validity of the axioms +(X → Y → (+X → +Y and +X → X, in terms of depth (complexity with respect to the operator + of X and Y , and also includes restricted versions of the axioms of positive and negative introspection. LER system results from the union of LER–n systems, and can be seen as the S5 modal logic system with different types of restrictions. Changing +X → X by +X →∼+∼X are built LDR–n and the LDR systems. LDR can be seen as the KD45 modal logic system with different types of restrictions. The systems are characterized with a embedded worlds semantics, with which the ‘omniscience logical problem’ is limited.Se presentan como extensiones del cálculo proposicional clásico las jerarquías de sistemas deductivos LER–n y LDR–n, con n ≥ 1. LER–n es la Lógica epistémica con restricciones de profundidad–n, LDR–n es la Lógica doxástica con restricciones de profundidad–n. Los sistemas LER–1 y LDR–1 son el cálculo proposicional clásico. El sistema LER–(n + 1 puede ser visto como el resultado de aplicar la regla: de X se infiere +X, una vez a los teoremas del sistema LER–n, además, se restringe la validez de los axiomas +(X → Y → (+X → +Y y +X → X en términos de la profundidad (complejidad respecto al operador + de X y de Y , y también se incluyen versiones generalizadas y con restricciones de los axiomas de introspección positiva y negativa. El sistema LER resulta de la reunión de los sistemas de la jerarquía, y puede ser visto

  7. Conrprop: un algoritmo para la optimización de funciones no lineales con restricciones

    Directory of Open Access Journals (Sweden)

    Fernán Villa

    2009-01-01

    Full Text Available Resilent backpropagation (RPROP es una poderosa técnica de optimización basada en gradientes que ha sido comúnmente usada para el entrenamiento de redes neuronales artificiales, la cual usa una velocidad por cada parámetro en el modelo. Aunque esta técnica es capaz de resolver problemas de optimización multivariada sin restricciones, no hay referencias sobre su uso en la literatura de investigación de operaciones. En este artículo, se propone una modificación de resilent backpropagation que permite resolver problemas no lineales de optimización sujetos a restricciones generales no lineales. El algoritmo propuesto fue probado usando seis problemas comunes de prueba; para todos los casos, el algoritmo de resilent backpropagation restringido encontró la solución óptima, y para algunos casos encontró un punto óptimo mejor que el reportado en la literatura.

  8. Simulation of the park for electric generation of the Argentine Republic, analysis of its possible expansion with restrictions in the disposability of the fossil fuels; Simulacion del parque de generacion electrica de la Republica Argentina, analisis de su posible expansion con restricciones en la disponibilidad de los combustibles fosiles

    Energy Technology Data Exchange (ETDEWEB)

    Giubergia, J H; Coppari, N R [Comision Nacional de Energia Atomica, Centro Atomico Constituyentes, Unidad de Actividad Reactores y Centrales Nucleares, Avda. Gral. Paz 1499 (1650) San Martin, Provincia de Buenos Aires (Argentina); Rey, F C [Comision Nacional de Energia Atomica, Centro Atomico Ezeiza, Presbitero Juan Gonzalez y Aragon 15, (B1802AYA) Ezeiza, Provincia de Buenos Aires (Argentina)

    2004-07-01

    In this work one simulates, using the program MESSAGE, the generation park electric of the Argentine Republic and their possible expansion, with restrictions in the readiness of fossil fuels. This, as other models of planning energetics promoted by IAEA, optimizes the expansion of the net having as function objective the smallest cost in the system. 25 years they were simulated, adopting like base the anus 2000 and considering different scenarios of internal and external demands. It was analysed the increase of the demand with restrictions in the readiness of the natural gas in the winter periods, since the Argentinean electric system has a great dependence of this fuel. To cover the increase of the electric demand, were selected the machines and fuels, at the moment available, with more technical and economic possibilities. In the scenarios without restrictions to the use of natural gas the program selects to the nuclear power station of Atucha II, to the increase of bench mark of the hydraulic power station of Yacireta and combined cycles that burn natural gas. In those in that the supply of natural gas is limited, it selects previously besides the signal ones, other nuclear power stations, other hydroelectric projects and turbines of gas operating with gas oil to cover the top requirements. (Author)

  9. Problema de Localización y Ruteo con Restricciones de Capacidad: Revisión de la Literatura

    Directory of Open Access Journals (Sweden)

    John Willmer Escobar

    2015-05-01

    Full Text Available En este artículo se hace una revisión exhaustiva del estado del arte de las metodologías de solución existentes para el problema combinado de localización y ruteo con restricciones de capacidad (CLRP. El problema de CLRP tiene una gran cantidad de aplicaciones prácticas en temas relacionados con transporte. Se ha propuesto el siguiente esquema de clasificación de acuerdo al método de solución: (1 Algoritmos Heurísticos Constructivos, (2 Algoritmos Heurísticos Basados en Clústeres, (3 Algoritmos Heurísticos Basados en Trayectoria, (4 Algoritmos Heurísticos Basados en Población, (5 Algoritmos Heurísticos Combinados, (6 Métodos Exactos. Se hace especial énfasis en fortalezas y debilidades de cada metodología publicada, identificando oportunidades de investigación y desarrollo en el área, en el contexto de la aplicación práctica de la problemática.

  10. Solución de problemas de ruteo de vehículos con restricciones de capacidad usando la teoría de grafos

    OpenAIRE

    Correa Espinal, Alexander Alberto; Cogollo Florez, Juan M; Salazar lopez, Juan Carlos

    2012-01-01

    La teoría de grafos es una herramienta para la solución de problemas de ruteo de vehículos con restricciones de capacidad (Capacitated Vehicle Routing Problem, CVRP). En este artículo se muestra la aplicación de una herramienta informática basada en la teoría de grafos para analizar y resolver un un problema CVRP en una empresa de transporte de carga a nivel nacional. El análisis se realizó en una flotilla de 13 vehículos con las mismas especificaciones técnicas y capacidad de carga similar (...

  11. Modelo matemático para resolver el problema de localización y ruteo con restricciones de capacidad considerando flota propia y subcontratada

    OpenAIRE

    Toro-Ocampo, Eliana Mirledy; Franco-Baquero, John Fredy; Gallego-Rendón, Ramón Alfonso

    2016-01-01

    Resumen: El problema de localización y ruteo con restricciones de capacidad (CLRP) consiste en la selección de depósitos y rutas para atender un conjunto de clientes para obtener el mínimo costo. Una variante de este problema, en la que se considera existe la posibilidad de subcontratar la operación de algunas (o todas) las rutas, es el problema de localización y ruteo con flota propia y flota subcontratada (CLRPPC). Este problema aparece cuando la flota propia es insuficiente para atender la...

  12. Consistencia interna y validez concurrente del cuestionario para evaluación de limitaciones y restricciones en niños con TDAH

    OpenAIRE

    Salamanca, L.M.

    2014-01-01

    El TDAH es uno de los diagnósticos más frecuentes en psiquiatría infantil, su diagnóstico temprano reviste una gran importancia para su intervención familiar, escolar y social. Basándose en la clasificación internacional del funcionamiento, la discapacidad y la salud CIF, se diseñó un cuestionario para la evaluación de limitaciones en la actividad y restricciones en la participaciónen niños con TDAH, el cuestionario CLARP-TDAH versión padres y profesores. El objetivo de este artículo es deter...

  13. Solution to the problem of optimum power flows with restrictions of safety by a modified particle optimizer; Solucion del problema de flujos de potencia optimo con restricciones de seguridad por un optimizador de particulas modificado

    Energy Technology Data Exchange (ETDEWEB)

    Onarte Yumbla, Pablo Enrique

    2008-02-15

    de las unidades de generacion para satisfacer la demanda del sistema al minimo costo de produccion, mientras se satisface un conjunto de restricciones operativas de las unidades de generacion y de los sistemas de potencia, a traves del ajuste de las variables de control. Hoy en dia los sistemas de transmision son considerados como una compania independiente, la cual proporciona acceso a todos los participantes. Un esquema de precios debe compensar a las companias de transmision de una manera justa por proveer los servicios de transmision y asignar los costos totales de transmision entre todos los usuarios de la red de transporte. En este trabajo, se emplea un esquema de precios basado en el metodo de rastreo para determinar la contribucion real de los generadores en cada una de las lineas de transmision. Ademas los sistemas de potencia deben ser capaces de resistir la perdida de un componente (ej. lineas, transformadores, generadores), sin poner en peligro el sistema, garantizando su seguridad. Este problema se conoce como flujos de potencia optimo con restricciones de seguridad (FPO-RS). Ademas restricciones como tiempos minimos de encendido y apagado, velocidades de cambio de generacion, perfiles de voltaje y restricciones de estabilidad transitoria son incluidas al problema de FPO-RS. Se propone utilizar un optimizador por enjambre de particulas con operadores de reconstruccion como herramienta de optimizacion para solucionar el problema propuesto. La metodologia propuesta utiliza los operadores de reconstruccion y terminos de penalizacion dinamicos para manejar las restricciones del problema planteado. La utilizacion de los operadores de reconstruccion permite incrementar el numero de particulas (posibles soluciones) que se encuentran dentro de la zona factible de busqueda, lo que reduce el tiempo de computo y mejora la calidad de la solucion encontrada.

  14. Analisis comparativo de una metaheuristica en base a algoritmo genetico vs un metodo de ramificacion y corte para un caso de entrega y recolección con restricciones de ventana de horario

    Directory of Open Access Journals (Sweden)

    Lopez, F.

    2004-07-01

    Full Text Available En la solución de problemas combinatorios, es importante evaluar el costo-beneficio entre la obtención de soluciones de alta calidad en detrimento de los recursos computacionales requeridos. El problema planteado es para el ruteo de un vehículo con entrega y recolección de producto y con restricciones de ventana de horario. En la práctica, dicho problema requiere ser atendido con instancias de gran escala (nodos ≥100. Existe un fuerte porcentaje de ventanas de horario activas (≥90% y con factores de amplitud ≥75%. El problema es NP-hard y por tal motivo la aplicación de un método de solución exacta para resolverlo en la práctica, está limitado por el tiempo requerido para la actividad de ruteo. Se propone un algoritmo genético especializado, el cual ofrece soluciones de buena calidad (% de optimalidad aceptables y en tiempos de ejecución computacional que hacen útil su aplicación en la práctica de la logística. Para comprobar la eficacia de la propuesta algorítmica se desarrolla un diseño experimental el cual hará uso de las soluciones óptimas obtenidas mediante un algoritmo de ramificación y corte sin límite de tiempo. Los resultados son favorables.

  15. UN ALGORITMO METAHEURÍSTICO BASADO EN RECOCIDO SIMULADO CON ESPACIO DE BÚSQUEDA GRANULAR PARA EL PROBLEMA DE LOCALIZACIÓN Y RUTEO CON RESTRICCIONES DE CAPACIDAD A META-HEURISTIC ALGORITHM BASED ON THE SIMULATED ANNEALING WITH GRANULAR SEARCH SPACE FOR THE CAPACITATED LOCATION ROUTING PROBLEM

    Directory of Open Access Journals (Sweden)

    John Willmer Escobar

    2012-12-01

    Full Text Available Consideramos el problema de localización y ruteo con restricciones de capacidad (CLRP, en el cual la meta es determinar los depósitos a ser abiertos, los clientes a ser asignados a cada depósito abierto, y las rutas a ser construidas para satisfacer las demandas de los clientes. El objetivo es minimizar la suma de los costos de abrir depósitos, de los costos de los vehículos usados, y de los costos variables asociados con la distancia recorrida por las rutas. En este paper, proponemos una metaheurística basada en simulado y recocido con espacio de búsqueda granular para resolver el problema CLRP. Experimentos computacionales en instancias de benchmarking tomadas de la literatura muestran que el algoritmo propuesto es capaz de obtener, dentro de tiempos computacionales razonables, soluciones de alta calidad mostrando su eficacia.The article deals with the Capacitated Location Routing Problem (CLRP where the goal is to determine the depots to be opened, the customers to be assigned to each deposit opened, and the routes to be constructed for fulfilling customers' demands. The objective is to minimize the sum of costs resulting from opening depots, costs resulting from used vehicles, and variable costs associated to the distance across the routes. In this paper, a metaheuristic based on simulated annealing with granular search space for solving the CLRP is proposed. Computational experiments on benchmarking instances taken from literature show that the proposed algorithm is able to obtain high-quality solutions within reasonable computational times, thus showing its efficiency.

  16. Going Up? The Pros and Cons of Vertical Expansion.

    Science.gov (United States)

    Myler, Patricia A.; Boggs, Richard C.

    2002-01-01

    Describes the advantages and disadvantages of the vertical expansion of school buildings. Considers such factors as fire protection, compliance with the Americans with Disabilities Act, and cost. Discusses alternatives to vertical expansion. (PKP)

  17. Propuesta para el manejo de restricciones en modelos de clases usando atom3

    OpenAIRE

    Carlos M. Zapata J.; Carlos A. Álvarez C.; Fernando Arango I.

    2005-01-01

    La construcción de los modelos para el desarrollo de software se ha realizado tradicionalmente con herramientas CASE. En estas herramientas los formalismos de cada modelo ya se encuentran plenamente definidos, lo que implica que no es posible agregarles nuevas restricciones. Las herramientas de Metamodelado surgieron como una manera de solución a este problema, pues poseen formalismos propios (generalmente gráficos) que permiten la expresión de diferentes modelos, incluyendo su...

  18. Teoría de restricciones para procesos de manufactura

    Directory of Open Access Journals (Sweden)

    Gabriela Villagómez

    2012-06-01

    Full Text Available La empresa “Productos Alexander” fabricante de snacks de la ciudad de Quito, tiene un sistema de producción que no permite el abastecimiento de los pedidos de sus clientes reflejando un índice de servicio al cliente de 89,58% ya que sus procesos están trabajando con capacidades que no se encuentran correctamente programadas, en vista de tal razón el objetivo de esta investigación es proponer un sistema de mejora continua con el fin de aumentar y efectivizar específicamente la producción de snacks de papas fritas utilizando la Teoría de Restricciones (TOC como metodología científica. Se realizó la medición de capacidad de cada una de las operaciones que componen el proceso de elaboración de snacks y se identificó la restricción en el proceso de fritura, que no estaba trabajando el 100% del tiempo en la jornada diaria limitando así la capacidad de la fábrica, por lo que se optó por explotar la restricción para eliminarla. La propuesta planteada para explotar la restricción consiste en una mejor programación de la producción, reducción de lote de transferencia de proceso a proceso, programación de la cantidad de trabajo para cada uno de los operarios en la jornada, la preparación del proceso y la fijación de turnos en la hora de almuerzo de los operarios lo que contribuye a agilizar el proceso de fritura y permitir que trabaje a su máxima capacidad el 100% del tiempo.Dicha propuesta se puede considerar como una solución al problema y así mejorar los niveles de producción de la empresa, tomando en cuenta que en base a los indicadores de TOC el Beneficio Neto de la empresa aumentaría de $15 333.09 a $ 17 392.14 al cumplir en cantidad y a tiempo todos los pedidos de los clientes.Abstract:The company "Products Alexander" snack manufacturer in the city of Quito, has a production system that cannot supply customer orders, with a customer service index of 89,58%, also their processes are working with capabilities that

  19. Planning the expansion of transmission with evolutionary programming; Planeacion de la expansion de transmision con programacion evolutiva

    Energy Technology Data Exchange (ETDEWEB)

    Ceciliano Meza, Jose Luis; Nieva Gomez, Rolando [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    A method of evolutionary programming for the planning of transmission networks in electrical power systems is presented. This is a whole problem mixed and nonlinear, with a combinatory nature that leads to a very large number of possible solutions for electrical systems of medium and large scale. The problem of transmission planning is described briefly and later it is formulated in mathematical terms. The proposed algorithm of evolutionary programming is applied to a large scale network that is representative of the Mexican electrical system. [Spanish] Se presenta un metodo de programacion evolutiva para la planeacion de redes de transmision en sistemas electricos de potencia. Este es un problema entero mixto y no lineal, con una naturaleza combinatoria que conduce a un numero muy grande de soluciones posibles para sistemas electricos de mediana y gran escala. Se describe brevemente el problema de planeacion de transmision y posteriormente se formula en terminos matematicos. El algoritmo propuesto de programacion evolutiva se aplica a una red electrica de gran escala que es representativa del sistema electrico Mexicano.

  20. Planning the expansion of electrical transmission networks with evolutionary programming; Planeacion de la expansion de redes de transmision electrica con programacion evolucionaria

    Energy Technology Data Exchange (ETDEWEB)

    Ceciliano Meza, Jose Luis

    1997-12-31

    In this work it is presented for the first time in the literature the solution of the problem of the planning the expansion of an electrical transmission network (PERTE) with the use of the Evolutionary Programming. The evolutionary programming is a stochastic method of optimization with similar characteristics to the generic algorithms, but different. During the development of this work it is shown what each one of these two heuristic methods of optimization consist of. Additionally, the main characteristics of other two heuristic methods known in the literature are described (Tabu Searching and Simulated Annealing). These two methods together with the genetic algorithms and decomposition of Benders have also been used to solve the problem of planning PERTE. The operation of the proposed algorithm of evolutionary programming was tested in two networks of electrical transmission. The first case of test is a system which is known in the literature. The second case is a representative system of the electrical transmission network of Central America. The results obtained improve all the results shown when applying different heuristic methods of optimization (genetic algorithms, simulated annealing and Tabu searching) to solve the same problem. [Espanol] En este trabajo se presenta por primera vez en la literatura, la solucion del problema de la planeacion de expansion de una red de transmision electrica (PERTE) con el uso de la Programacion Evolucionaria. La programacion evolucionaria es un metodo estocastico de optimizacion con caracteristicas similares a los algoritmos geneticos, pero diferente. Durante el desarrollo de este trabajo se muestra en que consiste cada uno de estos dos metodos heuristicos de optimizacion. Ademas, se describen las caracteristicas principales de otros dos metodos heuristicos conocidos en la literatura (busqueda Tabu y Recorrido Simulado). Estos dos metodos juntos con los algoritmos geneticos y descomposicion de Benders tambien han sido

  1. Desarrollo de una Metodolog?a de Implementaci?n de los Conceptos de TOC (Teor?a De Restricciones), para Empresas Colombianas

    OpenAIRE

    Gonzalez G?mez, Jos? Arturo; Orteg?n Mosquera, Katherine; Rivera Cadavid, Leonardo

    2003-01-01

    La Teor?a de Restricciones (TOC) es un sistema de pensamiento gerencial que ha sido aplicado con ?xito en multitud de empresas en el mundo. Sin embargo, no existe una documentaci?n adecuada de su implementaci?n en Peque?as y Medianas Empresas (PyMEs) en Colombia, por lo que no hay un protocolo de implementaci?n que gu?e al empresario en dicho proceso.Al realizar una investigaci?n documental, unida con un diagn?stico y aplicaci?n piloto en dos peque?as empresas del sector de manufactura de pro...

  2. Una metodología para desarrollar aplicaciones usando programación por restricciones

    OpenAIRE

    Díaz Araya, Daniel; Ibáñez, Francisco S.; Forradellas, Raymundo Quilez

    1999-01-01

    En los últimos años la programación por restricciones ha automatizado la solución de problemas combinatorios complejos en muchos dominios tan diversos como planificación, asignación de recursos, optimización, etc. En este trabajo describiremos una metodología general que permite desarrollar programas utilizando la tecnología de restricciones.

  3. Teoría de las restricciones: Una estructura conceptual para mejorar la práctica de la actividad gerencial

    OpenAIRE

    Hurtado Pimienta, Andrés

    2015-01-01

    Este trabajo se presenta con la intensión optar por el título de magister en filosofía. En él se analiza el concepto contemporáneo de la gerencia desde la perspectiva propia de la filosofía de la sociedad de Searle y Popper, y la perspectiva de la filosofía de la ciencia de Nagel y Popper. Como resultado se contraponen dos visiones diferentes de la gerencia, una que viene de Peter Drucker y otra que pretende solucionar los problemas de la primera: La Teoría de las Restricciones de El...

  4. Computación evolutiva de bosques de expansión mínimos con restricción de grado y de rol

    OpenAIRE

    Antón Sánchez, Laura

    2015-01-01

    Encontrar el árbol de expansión mínimo con restricción de grado de un grafo (DCMST por sus siglas en inglés) es un problema NP-complejo ampliamente estudiado. Una de sus aplicaciones más importantes es el dise~no de redes. Aquí nosotros tratamos una nueva variante del problema DCMST, que consiste en encontrar el árbol de expansión mínimo no solo con restricciones de grado, sino también con restricciones de rol (DRCMST), es decir, a~nadimos restricciones para restringir el rol ...

  5. Una formulación matemática y de solución para programar cirugías con restricciones de recursos humanos en el hospital público A mathematical formulation and solution to schedule surgeries with human resource constraints in a public hospital

    Directory of Open Access Journals (Sweden)

    Lorena Pradenas Rojas

    2012-08-01

    Full Text Available Actualmente, los hospitales públicos nacionales e internacionales presentan demandas que sobrepasan la capacidad de atención, lo que ha provocado un creciente interés por usar herramientas de gestión en los centros clínicos que les permita realizar de forma eficiente y eficaz la entrega de servicios a los distintos pacientes. El presente estudio aporta una nueva forma de abordar el problema de programación de cirugías, desde la programación matemática, presentando un modelo de optimización multiobjetivo y un algoritmo metaheurístico implementado computacionalmente, que permite la programación semanal de intervenciones quirúrgicas, cumpliendo con los requerimientos de pabellones y personal especializado necesario para su realización. Se utiliza una instancia de prueba, donde el tiempo de ejecución del algoritmo, implementado en C++, fue de siete minutos para 191 cirugías en lista de espera. El tiempo alcanzado es considerablemente menor a la programación realizada con un sistema manual, como los actualmente usados en hospitales públicos.Currently, national and international public hospitals have demands that exceed their service capacity, which has caused a growing interest in management sciences to deliver these medical centers the tools that will enable them to perform efficiently and effectively, delivering services to different patients. This study provides a new way of approaching the problem of surgical scheduling using mathematical programming, presenting a multi-objective optimization model and a metaheuristic algorithm implemented computationall. The solution allows weekly schedule of surgical procedure and complying with the requirements of the flag and expertise necessary for realization. We ordered test instances where the execution time of the algorithm, coded in C++, was 7 minutes for a 191 surgeries waiting list, which is a considerable less amount of time to this schedule than using a manual approach. The latest

  6. Detección de restricciones en la producción de agave azul (Agave tequilana Weber var. azul mediante percepción remota

    Directory of Open Access Journals (Sweden)

    Ramón Ceja Ramírez

    2017-07-01

    Full Text Available El agave azul (Agave tequilana Weber, var. azul se utiliza, principalmente, para la producción del Tequila; una bebida espirituosa. El estado de Jalisco, México, contribuye con el 90% de la producción; esto constituye un importante apoyo a la economía del Estado. El objetivo de la presente investigación fue determinar la superficie ocupada por agave azul, que presentó restricciones en su producción en la región Valles, correspondiente a los municipios de Tequila, Amatitán y El Arenal, en el estado de Jalisco, México, por medio de percepción remota. Se utilizó una imagen adquirida por el satélite LANDSAT 5 el 2 de abril de 2011, la cual se procesó para su calibración radiométrica, corrección atmosférica y georreferenciación. La interpretación digital se hizo a través del proceso de clasificación supervisada utilizando la opción de máxima probabilidad. Los campos de entrenamiento se seleccionaron de información de campo y de la base de datos del Consejo Regulador del Tequila (CRT. Los resultados se plasmaron en mapas temáticos; distribución de agave y no agave y distribución de agave con restricciones. El 45% del área ocupada por el cultivo presentó restricciones relacionadas con: aspectos económicos (restricción tipo 1, plagas y enfermedades (restricción tipo 2 y efectos por exceso de humedad del suelo (restricción tipo 3. Para evaluar la precisión de estos datos se aplicó una matriz de error que reportó una precisión general del 73%. Este valor es aceptable considerando la resolución a 30 m del sensor (LANDSAT 5 y la peculiaridad del cultivo. El uso de imágenes LANDSAT por su resolución espectral y radiométrica es aceptable para el estudio del cultivo del agave azul según lo observado en campo y lo expresado por el procesamiento de la imagen.

  7. TEORIA DE RESTRICCIONES Y SU PROCESO DE PENSAMIENTO

    OpenAIRE

    Aguilar, Orlando

    2003-01-01

    Hoy, m?s que nunca, el cambio es esencial para satisfacer las expectativas. Los clientes esperan pagar un precio justo por mejores productos y servicios. Los accionistas esperan hoy mayores rendimientos. Hoy, m?s que nunca, los empleados esperan tener un puesto asegurado. ?C?mo lograr, hoy, ma?ana y siempre estos objetivos, si la administraci?n est? con la constante presi?n de mantener los costos bajo control? A la luz de las constantes presiones competitivas y un mundo cambiante, el no...

  8. Planificación de la producción en una industria de consumo masivo utilizando la Teoría de las Restricciones

    OpenAIRE

    Cabrera Ojeda, Daniel Alejandro

    2014-01-01

    102 páginas : ilustraciones,29 x 21 cm + CD-ROM 5335 Se realizaron parametrizaciones en un simulador, para representar la realidad actual de una compañía manufacturera, y de cómo se debe manejar, la planificación de la producción y la cadena de distribución con base en la teoría de las restricciones. Lo que conllevó que se tenga una disminución de 15 800 000 USA dólares en los niveles de inventario a lo largo del período analizado; es decir, al correr la simulación antes de la implementaci...

  9. Planning model for the expansion of the electrical generation system with risk demarcation criteria; Modelo para la planificacion de la expansion del sistema electrico de generacion con criterios de acotamiento de riesgo

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Galicia, Julio Alberto; Nieva Gomez, Rolando [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2009-07-01

    The general characteristics of a planning model for the electrical generation system expansion with risk demarcation criteria, as well as the main results of a representative study case of the Mexican Electrical System is presented. The model is based on a methodology of multiannual optimization for the generation expansion plans determination. In this context, every expansion plan defines the technology type to be installed, as well as the installation year, unit size and its location within a regional electric network. For this purpose, the model considers an interregional representation of the system identifying the necessary reinforcements to the capacity of the interregional connections. It also incorporates a Demarcation of Risk module that considers the uncertainty of the future scenarios of fuels prices to generate a set of expansion plans, among which includes the following: a) For every future of the fuel prices: the plan that diminishes the present value of the total cost (investment plus production). b) The plan that diminishes the economic risk derived from the uncertainty in the future of the fuel prices. c) A subgroup of expansion plans that are located in the efficient borders of decision, under the context of three criteria of interest: the economic risk, the investment cost of and the total cost in the future considered of greater relevance. [Spanish] Se presentan las caracteristicas generales de un modelo de planificacion de la expansion del sistema electrico de generacion con criterios de acotamiento de riesgo, asi como los principales resultados de un caso de estudio representativo del Sistema Electrico Mexicano. El modelo se basa en una metodologia de optimacion multi-anual para la determinacion de planes de expansion de la generacion. En este contexto, cada plan de expansion define el tipo de tecnologia que debera instalarse, asi como el ano de instalacion, el tamano de la unidad y su localizacion dentro de una red electrica regional. Para

  10. Aplicación de la Teoría de Restricciones y su Incidencia en los Costos de Producción en la Empresa MIVIRN, de la ciudad de Riobamba provincia de Chimborazo.

    OpenAIRE

    Guananga Díaz, Freddy Román

    2017-01-01

    El presente proyecto de investigación tuvo como objetivo la elaboración una propuesta de mejora para la empresa MIVIRN aplicando la Metodología de la Teoría de Restricciones (TOC), para minimizar los costos de producción. En el desarrollo de la investigación se logra establecer la demanda histórica y en base a esta se proyecta la demanda futura, que permite evaluar y determinar los tiempos estándar, se costea los centros de producción mediante el costeo directo, con estos ...

  11. Programación de la producción de calzado de seguridad basado en la teoría de restricciones para la mejora de la productividad en la Empresa Marcia- Buffalo Industrial.

    OpenAIRE

    Aldás Salazar, Darwin Santiago

    2016-01-01

    Se realizó un estudio de los parámetros de producción en la empresa de calzado de seguridad MARCIA BUFALO INDUSTRIAL; como: inventario en proceso por sus siglas en inglés (WIP), tiempo de ciclo (CT) y tasa de producción de unidades vendibles throughput (TH), los parámetros se obtienen de la teoría de restricciones propuesta por Goldratt y luego se las evaluó con la Ley de Little que propone Hopp y Spearman, se aplicó el estudio realizado para programar la producción de calzado de seguridad qu...

  12. Restricciones de desarrollo y selección natural: una perspectiva teórica y epistémica desde la teoría de la complejidad

    Directory of Open Access Journals (Sweden)

    Dressino, Vicente

    2013-12-01

    Full Text Available La utilización del término “restricciones” (constraints en biología incluye todos los niveles de organización y es aplicado a diversas disciplinas. Esto genera numerosas confusiones debido a la vaguedad del término en referencia a las distintas particularidades en que es utilizado. Y en general, no se justifica de forma adecuada por qué se utiliza este término y en qué sentido es usado. Asimismo, cuando se analiza el término “restricción” desde la perspectiva de la complejidad, asume un significado más difuso. El objetivo del presente trabajo es realizar un análisis de los problemas teóricos que presenta el uso de las restricciones de desarrollo, su relación con otros tipos de restricciones y con el concepto de selección natural. Se concluye que el término “restricción de desarrollo” es innecesario y polisémico. Asimismo, su capacidad explicativa es dudosa y no corroborable con los métodos científicos actuales.

  13. Estímulos y restricciones para la investigación en administración en Colombia

    Directory of Open Access Journals (Sweden)

    Liliana María Gutiérrez Vargas

    2013-09-01

    Full Text Available Este artículo presenta los estímulos y restricciones que tiene la investigación en administración en Colombia, partiendo de las consideraciones generales del país, como la política de Ciencia y Tecnología, las consideraciones de calidad que impone el Ministerio de Educación Nacional a los programas curriculares y las condiciones propias que hacia el fortalecimiento de la investigación ofrecen las universidades y las facultades de administración en el país. El trabajo empírico se desarrolló con investigadores y decanos de las facultades, mediante una encuesta online en la que participaron 194 investigadores (tasa de respuesta de 30,6% y 63 decanos o directores de programas (tasa de respuesta del 27,7%; adicionalmente, se seleccionó una muestra intencional de 25 investigadores y 11 decanos para realizar entrevistas a profundidad, y se realizaron tres grupos focales. Los principales hallazgos en referencia se evidencian en: recursos para investigar, estímulos económicos para los investigadores, la política de ciencia y tecnología, la comunidad científica, las formas de divulgación de los resultados investigativos y los aspectos administrativos; puntos estos que vienen siendo analizados como políticas institucionales por las universidades para fomentar la investigación. Sin duda, los esfuerzos que se focalicen para minimizar los restrictores potencian el desarrollo de esta incipiente comunidad académica.

  14. Allocation of the transmission service cost with base in marginal costs of the transmission network expansion; Asignacion del costo del servicio de transmision con base en costos marginales de expansion de la red de transmision

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz Casillas, Manuel E.; Nieva Gomez, Rolando [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    2001-07-01

    The transmission charges to the users must be completely defined in those systems where the restructuring has broken up the traditional functions of the companies; in order to introduce competition in the generation and commercialization segments of the electrical energy. The fundamentals of a method used are explained to assure the transmission service cases between their users. The method is based on the marginal expansion costs of the transmission network. Their more known applications have been in competitive markets of energy, in particular, where the energy price is the same one in all the localities. Nevertheless, it can be used under other forms of organization of the electrical industry. In order to illustrate results, the obtained ones from their application to the most important part of the transmission network of the Mexican system that operates interconnected, are presented. [Spanish] Los cargos de transmision a los usuarios deben estar completamente definidos en aquellos sistemas donde la reestructuracion ha desagregado las funciones tradicionales de las empresas; para introducir competencia en los segmentos de generacion y comercializacion de la energia electrica. Se explican los fundamentos de un metodo utilizado para asegurar los casos del servicio de transmision entre sus usuarios. El metodo se basa en los costos marginales de expansion de la red de transmision. Sus aplicaciones mas conocidas han sido en mercados competitivos de energia, en particular, donde el precio de la energia es el mismo en todas las localidades. Sin embargo, puede utilizarse bajo otras formas de organizacion de la industria electrica. Con el proposito de ilustrar resultados, se muestran los obtenidos de su aplicacion a la parte mas importante de la red de transmision del sistema mexicano que opera interconectada.

  15. DESARROLLO DE UNA METODOLOGÍA DE IMPLEMENTACIÓN DE LOS CONCEPTOS DE TOC (TEORÍA DE RESTRICCIONES, PARA EMPRESAS COLOMBIANAS

    Directory of Open Access Journals (Sweden)

    José Arturo Gonzáles Gómez

    2003-01-01

    Full Text Available La Teoría de Restricciones (TOC es un sistema de pensamiento gerencial que ha sido aplicado con éxito en multitud de empresas en el mundo. Sin embargo, no existe una documentación adecuada de su implementación en Pequeñas y Medianas Empresas (PyMEs en Colombia, por lo que no hay un protocolo de implementación que guíe al empresario en dicho proceso. Al realizar una investigación documental, unida con un diagnóstico y aplicación piloto en dos pequeñas empresas del sector de manufactura de productos plásticos, se estructuró una propuesta que parte desde conocer el estado actual de la empresa, satisfacer algunos requerimientos previos a la implementación de técnicas de TOC y la implementación propiamente dicha de las mismas. Como conclusión se encontró que antes de emprender cualquier proceso de mejoramiento es necesario “ordenar la casa”: Lograr una claridad en los aspectos administrativos, productivos y de calidad básicos, para así garantizar la efectividad y sostenibilidad de cualquier avance que se alcance.

  16. Aplicación de un juego de empresa como recurso didáctico para mejorar la enseñanza-aprendizaje del planeamiento y control de la producción según el modelo de teoría de restricciones

    OpenAIRE

    Tapia Vargas, Flor de María Milagros

    2014-01-01

    Esta tesis tiene como objetivo poner a disposición de la comunidad académica y empresarial un juego de empresa, como recurso didáctico, que permitirá mejorar la enseñanza-aprendizaje del planeamiento y control de la producción según el modelo de teoría de restricciones. El juego propuesto simula una línea de producción con ocho centros de trabajo, de los cuales, el cuarto es el cuello de botella, y el séptimo es el de ensamble. Para cumplir con los objetivos del estudio y someter a prue...

  17. SELECCIÓN DE PORTAFOLIOS DE INVERSIÓN SOCIALMENTE RESPONSABLES USANDO EL MÉTODO DE LAS RESTRICCIONES Y LA TÉCNICA MULTICRITERIO PROCESO ANALÍTICO JERÁRQUICO

    Directory of Open Access Journals (Sweden)

    Lady Mayerly Bernard Suárez

    Full Text Available En este artículo se presenta un procedimiento que permite apoyar el proceso de decisión de los inversionistas al seleccionar un portafolio que cumpla con sus expectativas económicas y con aquellas relacionadas con Responsabilidad Social Empresarial (RSE. Para ello, se consideran criterios de rentabilidad y riesgo como medidas económicas que, abordadas desde el método de las restricciones, dan como resultado una serie de portafolios eficientes que se emplean como alternativas para la aplicación de la técnica multicriterio AHP (sigla en inglés, la cual permite establecer el portafolio que cumple con criterios de gobierno corporativo, relaciones con colaboradores, medio ambiente y relaciones con la comunidad como medidas de RSE. El procedimiento se aplica en la selección de portafolios de inversión para acciones del mercado bursátil colombiano, dando como resultado que el portafolio que mejor cumple con los criterios establecidos en este artículo para RSE también es el de mínimo riesgo.

  18. Modelado de Materiales Compuestos por Elementos Finitos usando Restricciones Cinemáticas Finite Element Modeling of Composite Materials using Kinematic Constraints

    Directory of Open Access Journals (Sweden)

    Oscar E. Ruiz

    2009-12-01

    Full Text Available El propósito de este artículo es presentar simulaciones del comportamiento de materiales compuestos basado en restricciones cinemáticas entre las mismas fibras y entre las fibras y la resina circundante. En la revisión de literatura, los autores han encontrado que las restricciones cinemáticas no han sido plenamente explotadas para modelar materiales compuestos, probablemente debido a su alto costo computacional. El propósito de este articulo es exponer la implementación y resultados de tal modelo, usando Análisis por Elementos Finitos de restricciones geométricas prescritas a los nodos de la resina y las fibras. Las descripciones analíticas del comportamiento de materiales compuestos raramente aparecen. Muchas aproximaciones para describir materiales compuestos en capas son basadas en la teoría de funciones C1Z y C0 Z, tal como la Teoría Clásica de Capas (CLT. Estas teorías de funciones contienen significativas simplificaciones del material, especialmente para compuestos tejidos. Una aproximación hibrida para modelar materiales compuestos con Elementos Finitos (FEA fue desarrollada por Sidhu y Averill y adaptada por Li y Sherwood para materiales compuestos tejidos con polipropileno de vidrio.The purpose of this article is to present simulations of the behavior of composite materials based on kinematic restrictions among the fibers themselves and among fibers and the surrounding resine. In the literature review the authors have found that the kinematic restrictions have not been fully exploited for modeling composite materials, probably due to their high computational expense. The purpose of this article is to show the implementation and results of such a model, by using a Finite Element Analysis of geometric restrictions prescribed to the resine and fiber nodes. Closed analytic descriptions on behavior of layered composite materials are very rare. Many approaches to describe layered composite material are based on the theory of

  19. Restricciones en el canal de comunicación y representación de influencia en situación de toma de decisión Restrictions in the communication channel and influence representation in taking up decisions

    Directory of Open Access Journals (Sweden)

    Jorge R. Vivas

    2001-06-01

    Full Text Available La comunicación mediada por computadora ha tenido un efecto de alto impacto social en la última década. Los efectos psicosociales de la utilización de estos medios tecnológicos en la comunicación humana son observados con creciente interés. Este trabajo reporta las variaciones de la percepción de influencia durante una tarea de toma de decisión colaborativa al modificar las restricciones del canal de comunicación (presencial o mediado por computadora. Se trabajó con cien sujetos repartidos en ambas condiciones de tarea sobre un problema de decisión múltiple. Los análisis muestran una diferencia notable en los aspectos considerados por los individuos para la construcción de la representación de influencia en una y otra modalidad. Estas diferencias son interpretadas como producto de que la magnitud de la presencia social esta modulada por las restricciones inherentes al canal mediador, dificultando y hasta impidiendo, la percepción de los mecanismos de influencia social que permiten la construcción de una representación de influencia ajustada a los efectivos intercambios realizados en torno al producto generado colaborativamente.Computer mediated communication had a high social impact in the last decade. The psychosocial effects of the use of these technological media on human communication are observed with growing interest. This work reports the differences of influence perception during the collaborative making decision task when varying the communicational channel restrictions (Face To Face or computer mediated. The design included a hundred students in both task conditions on a multiple decision problem. The outcomes show a great differences in how individuals remarks different aspects for the representational construction of the influence in each modality. These results suggest that the amount of social presence is modulated by the channel restrictions, which make it difficult and even constrain, the perception of the

  20. Crecimiento, acumulación y empleo en una economía con tasa de inflación constante : implicaciones de política económica

    OpenAIRE

    Uxó González, Jorge

    1994-01-01

    Los objetivos fundamentales de la tesis son analizar que tipo de restricciones impiden a las economías de mercado creer a un ritmo suficiente para evitar la aparicion de desempleo, y estudiar la influencia de la politica económica sobre dichas restricciones. En la primera parte se define y obtiene la tasa de crecimiento no aceleradora de la inflación. En la segunda parte se estudia la dinámica de la economía suponiendo que la tasa de crecimiento efectiva coincide siempre con la no aceleradora...

  1. Pros and cons of an expansion of the natural gas system in the Nordic Countries - sensitivity analysis of the scenario results from stage one of the Nordleden project

    International Nuclear Information System (INIS)

    2001-12-01

    The report shows that the maximum economic profit from a transnordic gas grid amounts to 5-30 billion SEK (0.5-3 billion USD), depending on scenarios. This holds even under relatively strict CO 2 limitations. The profit is in the same range as the profits from emissions trading or from free trade in electricity in the Nordic market. In absolute numbers, the profit increases with increased energy demand. The natural gas supply could amount to about 300 TWh in year 2030, if the price at the border does not surpass 70 SEK/MWh (7 USD/MWh). The main expansion would be in central power and heat production. However, the report also shows that the transnordic gas grid could become a burden for the Nordic energy system, as the profit could be negative in the case where the investment is done according to the design case, but the gas price gets higher. The worst case could result in a loss of about 30 billion SEK. However, it is probably more realistic to assume that the market actors try to minimize their own risks through long term contracts with fixed prices and volumes, leading to a transfer of the risk to the society as a whole, being forced to renounce cheaper solutions for reaching the environmental goals in the case where natural gas becomes a more expensive fuel than supposed in the planning stage. The corresponding risk is much lower from a CO 2 point of view, i.e. if future CO 2 reduction limit become more strict than in the planning stage, the value of the gas grid is only marginally affected. Sensitivity analysis where the Nordic cooperation is widened to include trade in electricity (which already is a fact) and emission rights show that the optimum natural gas supply is affected, but to a small degree only. The net effect is a certain redistribution of the natural gas use between the countries

  2. Estimación y análisis de precios nodales como efecto de las restricciones de transmisión en el mercado mayorista de Colombia

    Directory of Open Access Journals (Sweden)

    Luis Eduardo Gallego Vega

    2010-09-01

    Full Text Available El presente artículo presenta los resultados de una investigación sobre la estimación y análisis de precios nodales para el sistema de transmisión nacional de Colombia, como una alternativa para analizar el efecto de las restricciones de transmisión en el mercado mayorista de Colombia. Esta alternativa se plantea contra el modelo actual del mercado mayorista, el cual consiste en un modelo uninodal del sistema, sin darle un tratamiento adecuado a las restricciones de transmisión. La investigación describe el modelamiento del sistema de transmisión nacional, el modelamiento de la operación del despacho económico en el país y una metodología de refinamiento que incluye tanto las restricciones eléctricas como operativas del sistema. Como resultados se presenta un análisis de los precios nodales obtenidos para cada área operativa del sistema de transmisión colombiano y un análisis sobre las rentas de congestión del sistema.

  3. Las reglas del juego político en Chile: incentivos y restricciones para la gobernabilidad

    Directory of Open Access Journals (Sweden)

    Marco MORENO

    2009-11-01

    Full Text Available RESUMEN: El propósito del artículo es explorar las instituciones y reglas del juego que rigen el comportamiento y las relaciones entre los actores políticos chilenos desde una perspectiva de gobernabilidad democrática. Se examina en qué forma las instituciones y reglas del juego –formales e informales– contribuyen positiva o negativamente a la gobernabilidad democrática en Chile. Se centrará la atención primero en las instituciones políticas de carácter formal y después, en las de carácter informal. Al examinar las instituciones de carácter formal se distinguirá a aquellas que se vinculan más estrechamente con la forma de gobierno, los mecanismos de pesos y contrapesos, el sistema electoral y el sistema de partidos. En las informales se repasarán brevemente aquellas más visibles: clientelismo, circuitos extrainstitucionales del poder y captura del Estado. El punto de partida para este análisis recoge la idea de que un criterio clave para determinar el nivel de la consolidación democrática en un país es el que resulta de una adecuación razonablemente cercana entre reglas formales y comportamientos y prácticas de los actores.ABSTRACT: The intention of this article is to explore the institutions and rules of the game that govern the behavior of and relations between Chilean political actors from a perspective of democratic governability. It examines the ways in which the institutions and rules of the game –both formal and informal– contribute positively or negatively to democratic governability in Chile. It first focuses its attention on formal political institutions and later examines those that are informal in nature. When examining formal institutions, a special emphasis is put on those most closely linked to the form of government, the mechanisms of weights and counterweights, the electoral system and the party system. The examination of informal institutions concentrates on the most visible such institutions

  4. Thermal expansion

    International Nuclear Information System (INIS)

    Yun, Y.

    2015-01-01

    Thermal expansion of fuel pellet is an important property which limits the lifetime of the fuels in reactors, because it affects both the pellet and cladding mechanical interaction and the gap conductivity. By fitting a number of available measured data, recommended equations have been presented and successfully used to estimate thermal expansion coefficient of the nuclear fuel pellet. However, due to large scatter of the measured data, non-consensus data have been omitted in formulating the equations. Also, the equation is strongly governed by the lack of appropriate experimental data. For those reasons, it is important to develop theoretical methodologies to better describe thermal expansion behaviour of nuclear fuel. In particular, first-principles and molecular dynamics simulations have been certainly contributed to predict reliable thermal expansion without fitting the measured data. Furthermore, the two theoretical techniques have improved on understanding the change of fuel dimension by describing the atomic-scale processes associated with lattice expansion in the fuels. (author)

  5. Los sistemas de compensación financiera: Una restriccion en el cumplimiento de los objetivos de atraer, retener y motivar

    OpenAIRE

    García Cano, Olga Lucía

    2005-01-01

    Tesis (Maestría en Gerencia del Talento Humano). Universidad de Manizales. Facultad de Ciencias Sociales y Humanas, 2005 El propósito principal del presente estudio es identificar las posibles restricciones existentes entre los sistemas de compensación financiera y los objetivos de atraer, retener y motivar a los trabajadores en las organizaciones, buscando las características que debería tener un sistemas de compensación financiera estratégicamente adecuado tanto para los trab...

  6. Las restricciones y los aranceles a las exportaciones de mercancías en el Derecho de la OMC ¿barreras tradicionales o neoproteccionismo?

    OpenAIRE

    Baena Rojas, José Jaime

    2016-01-01

    [spa] Las restricciones y los aranceles a las exportaciones de mercancías han venido constituyéndose en una política comercial cada vez más común dentro del sistema multilateral de comercio. De hecho las diferencias alusivas a este tema ante el Órgano de Solución de Diferencias (OSD) han aumentado, lo que demuestra de alguna manera que la dinámica del comercio internacional ha cambiado, situación que supone un nuevo reto dentro de la Organización Mundial de Comercio (OMC). Teniendo en cuenta ...

  7. Restrições causadas pela incontinência urinária à vida da mulher Restricciones ocasionadas por la incontinencia urinaria en la vida de la mujer Urinary incontinence restrictions in women's life

    Directory of Open Access Journals (Sweden)

    Maria Helena Baena de Moraes Lopes

    2006-03-01

    Full Text Available O objetivo deste estudo foi identificar as restrições causadas pela incontinência urinária (IU à vida da mulher, considerando-se o tipo de incontinência, e verificar como manejam este problema. Trata-se de uma análise secundária de dados obtidos em estudo anterior, coletados por meio de entrevista com perguntas abertas e fechadas. A amostra foi composta por 164 mulheres com queixa de IU, internadas em clínicas de ginecologia e urologia de dois hospitais-escola da cidade de Campinas, SP. Apresentavam idade entre 25 e 85 anos e 104 (64% referiram uma ou mais restrições. Citaram alterações nas atividades sexuais (40,9%, sociais (33,5%, domésticas (18,9% e ocupacionais (15,2%. A incontinência urinária mista e a de urgência forem as que mais afetavam a vida das mulheres. A estratégia mais utilizada para minimizar a IU foi o uso de forro e/ou absorvente higiênico. Concluiu-se que a IU tem implicações negativas no cotidiano dessas mulheres.En este estudio se tuvo como objetivo identificar las restricciones causadas por la incontinencia urinaria (IU en la vida de la mujer, considerándose el tipo de incontinencia, y verificar cómo manejan este problema. Se trata de un análisis secundario de datos obtenidos en un estudio anterior, recolectados por medio de entrevista con preguntas abiertas y cerradas. La muestra estuvo compuesta por 164 mujeres con queja de IU, internadas en clínicas de ginecología y urología de dos hospitales docentes de la ciudad de Campinas, SP. Las mujeres tenían entre 25 y 85 años de edad, habiendo relatado 104 (64% de ellas una o más restricciones. Citaron alteraciones en las actividades sexuales (40,9%, sociales (33,5%, domésticas (18,9% y ocupacionales (15,2%. La incontinencia urinaria mixta y la de urgencia fueron las que más afectaban la vida de las mujeres. La estrategia más utilizada para minimizar la IU fue el uso de paños y/o toallas higiénicas. Se concluyó que la IU tiene implicancias

  8. Transformaciones en la producción simbólica en la clínica con niños con problemas de aprendizaje provenientes de contextos de pobreza

    OpenAIRE

    Grunberg, Débora; Yapura, Cristina

    2013-01-01

    El presente trabajo surge a partir de interrogantes formulados al interior de la Cátedra de Psicopedagogía Clínica (Facultad de Psicología, UBA), especialmente en espacios clínicos e investigativos. Su objetivo central es atender una temática latente en la clínica psicopedagógica de niños con problemas de aprendizaje que tiene lugar en el Servicio de Asistencia de la Cátedra: el despliegue y las restricciones de los procesos imaginativos de niños con dificultades de simbolización, en tanto pr...

  9. Técnicas borrosas para el análisis de la sensibilidad en la selección de carteras con restricciones de diversificación

    Directory of Open Access Journals (Sweden)

    Liern, Vicente

    Full Text Available We use fuzzy set theory to obtain alternative solutions to the Portfolio Selection Problemthat can better fit the inverstor’s preferences about the expected return and the corresponding risk of theefficient portfolio he or she finally chooses. We show by means of an example that, when diversificationconstraints are incorporated into the portfolio selection problem, the characteristics of the optimal efficientportfolio (composition, risk and expected return can be very sensitive to small variations of the parametersasociated to the investor’s subjective preferences, and then the fuzzy alternatives provided by our methodcan substantially improve the investor’s satisfaction.

  10. Técnicas borrosas para el análisis de la sensibilidad en la selección de carteras con restricciones de diversificación

    Directory of Open Access Journals (Sweden)

    Ivorra, Carlos

    2012-01-01

    Full Text Available We use fuzzy set theory to obtain alternative solutions to the Portfolio Selection Problemthat can better fit the inverstor’s preferences about the expected return and the corresponding risk of theefficient portfolio he or she finally chooses. We show by means of an example that, when diversificationconstraints are incorporated into the portfolio selection problem, the characteristics of the optimal efficientportfolio (composition, risk and expected return can be very sensitive to small variations of the parametersasociated to the investor’s subjective preferences, and then the fuzzy alternatives provided by our methodcan substantially improve the investor’s satisfaction.

  11. Accesibilidad espacial escolar en patios para alumnos con restricciones visuales: la construcción de un instrumento de evaluación

    Directory of Open Access Journals (Sweden)

    Andrea de Aguiar Kasper

    2009-06-01

    Full Text Available To enable visually impaired students to attend regular schools, these students must not only have suitable monitoring, but must also be able to take part in all school activities without any major impediments. This means that the many existing barriers to this inclusion must neutralized or even eliminated. In addition to teaching barriers, there are also barriers concerning social aspects and the physical space. This articles focuses on spatial accessibility in schoolyards and shows that, when these environments disregard the needs of students - such as in terms of physical and cognitive needs - access can be made difficult or even impossible, limiting these individuals' performance in the physical space. Accordingly, it is necessary to identify the physical barriers in these environments before planning any spatial accessibility initiatives. Based on this assumption, the current article suggests procedures for building an assessment tool for spatial accessibility in primary level public schools in regards to visually impaired students. The full instrument consists of 10 tables that refer to given environments and situations in primary public schools in the state of Santa Catarina, Brazil. The article presents the steps used to prepare and improve the tables in the schoolyards, as well as the setup of the tables. With improved schoolyard tables, the possibility of creating other tables under this instrument in order to improve other areas is demonstrated in the current article.

  12. Asymptotic Expansions - Methods and Applications

    International Nuclear Information System (INIS)

    Harlander, R.

    1999-01-01

    Different viewpoints on the asymptotic expansion of Feynman diagrams are reviewed. The relations between the field theoretic and diagrammatic approaches are sketched. The focus is on problems with large masses or large external momenta. Several recent applications also for other limiting cases are touched upon. Finally, the pros and cons of the different approaches are briefly discussed. (author)

  13. Expansion dynamics

    International Nuclear Information System (INIS)

    Knoll, J.

    1985-10-01

    A quantum dynamical model is suggested which describes the expansion and disassembly phase of highly excited compounds formed in energetic heavy-ion collisions. First applications in two space and one time dimensional model world are discussed and qualitatively compared to standard freeze-out concepts. (orig.)

  14. expansion method

    Indian Academy of Sciences (India)

    of a system under investigation is to model the system in terms of some ... The organization of the paper is as follows: In §2, a brief account of the (G /G)- expansion ...... It is interesting to note that from the general results, one can easily recover.

  15. Control Multivariable Centralizado con Desacoplo para Aerogeneradores de Velocidad Variable

    Directory of Open Access Journals (Sweden)

    Miguel E. González

    2010-10-01

    Full Text Available Resumen: El diseño de sistemas de control para aerogeneradores de velocidad variable representa un reto importante ya que se trata de procesos multivariables no lineales, con fuertes perturbaciones, diversas restricciones y gran interacción entre sus variables. Bajo este escenario se debe generar eficientemente la potencia eléctrica y al mismo tiempo regular la velocidad de giro de la turbina. En este trabajo se proponen varios esquemas de control multivariable, con el objetivo de mejorar el rendimiento de los aerogeneradores atenuando los efectos de la interacción entre sus variables. La solución propuesta se basa en controladores PID con diseños del tipo descentralizado, centralizado con diversas redes de desacoplo y un esquema con cuatro PI. El comportamiento del aerogenerador se describe mediante un modelo matemático no lineal, que se linealiza para obtener una matriz de funciones de transferencia, a partir de la cual se diseñan los controladores. Finalmente se realiza un análisis comparativo para determinar qué controlador presenta mejores resultados, aplicando perturbaciones con un modelo de la velocidad del viento y cambios aleatorios de la carga eléctrica. Palabras Clave: Aerogenerador, Control Multivariable, Modelado e Interacción

  16. Restricciones funcionales en la elisión del Marcador de Plural en el Español de Caracas

    OpenAIRE

    Ruiz Sánchez, Carmen

    2005-01-01

    En este trabajo se analizan y explican los factores funcionales que condicionan la elisión de la /-s/ plural en el español de Caracas. La codificación y el análisis de los datos sigue el planteamiento de Poplack (1980) con el fin de demostrar que la elisión de la marca de plural depende de la compleja combinación de factores morfológicos, semánticos y sintácticos, apoyándose así en una nueva interpretación de la hipótesis funcional de Kiparsky (1972), en la cual se reconoce la importancia de ...

  17. DESARROLLO E IMPLEMENTACIÓN DE UN MODELO DE TEORÍA DE RESTRICCIONES PARA SINCRONIZAR LAS OPERACIONES EN LA CADENA DE SUMINISTRO

    Directory of Open Access Journals (Sweden)

    William Marín Marín

    Full Text Available En este artículo se presenta una propuesta metodológica y práctica que permite sincronizar las operaciones y las decisiones en una cadena de suministro de una empresa del sector de revestimientos cerámicos en Colombia. Para ello se utilizaron dos herramientas de Teoría de Restricciones (TOC: la primera asociada a la sincronización de operaciones de la cadena de suministro (método Drum-Buffer-Rope, y la segunda, al desarrollo de una herramienta contable que permita mejorar la toma de decisiones de cada miembro de la cadena de suministro (Contabilidad de Throughput. Los resultados de la implementación muestran que mediante un análisis integral de la cadena de suministro puede mejorarse el desempeño de métricas globales como el nivel de servicio al cliente, el cumplimiento de los programas de producción, el costo de inventarios de materias primas y producto terminado, y la productividad de la empresa.

  18. Restricciones ontológicas en la política de calidad del aire en Bogotá

    Directory of Open Access Journals (Sweden)

    Héctor García Lozada

    2009-11-01

    Full Text Available Se examinan tres momentos de la política de calidad del aire en Bogotá (1974-2007, desde la perspectiva constructivista y desde el análisis crítico del discurso, con la intención de develar los paradigmas que sustentan estas decisiones así como la influencia de los actores sociales, en el contexto de un mundo globalizado y neoliberal. La precaria comprensión de la problemática le imprime a las políticas un sello de inoperancia que supera ampliamente las expectativas que sugieren sus textos, pero permite que la tecno-burocracia justifique el cumplimiento de sus obligaciones sin que se logren transformar o revertir las situaciones indeseables. / Three moments of the Bogota´s air quality policies (1974-2007 are examined, from the constructivist perspective and of the critical analysis of the discourse, with the purpose of reveal the paradigms that sustain these decisions as well as the influence of the social actors, in the context of an globalized and neoliberal world. The precarious comprehension of the problems prints on the policies ones a stamp of ineffectiveness that overcomes widely the expectations that suggest his texts but it allows that the tecno-bureaucracy should justify the fulfillment of his obligations without one manages to transform, or reverse, the undesirable situations

  19. Destrucción con peróxido de hidrógeno del cianuro residual de las pruebas de cianuración de oro

    OpenAIRE

    Rupay Güere, Felipe

    2013-01-01

    La investigación es aplicada con diseño estadístico. La Hidrometalúrgia está aplicándose cada vez más, porque se está constituyendo en el medio acertado para hacer frente a las restricciones de contaminación del medio ambiente impuestas a las empresas mineras; consecuentemente se desarrolla pruebas experimentales utilizando el cianuro como reactivo principal cuyos residuos generan problemas ambientales. Estas dificultades obligan a buscar nuevas alternativas de tratamiento de efluentes como l...

  20. Finite element model for expansive stress due to corrosion of reinforced concrete structures; Analisis con elemento finito de los esfuerzos expansivos por corrosion en las estructuras de concreto reforzado

    Energy Technology Data Exchange (ETDEWEB)

    Castorena Gonzalez, J.H.; Calderon Guillen, J.A. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: kstor28@yahoo.com.mx; cajoel_99@yahoo.com; Almeraya Calderon, F.; Gaona Tiburcio, C. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: facundo.almeraya@cimav.edu.mx; citlalli.gaona@cimav.edu.mx; Almaral Sanchez, J.L. [Universidad Autonoma de Sinaloa, Los Mochis, Sinaloa (Mexico)]. E-mail: jalmaral@gmail.com; Martinez Villafane, A. [Centro de Investigacion en Materiales Avanzados, S.C., Chihuahua, Chihuahua (Mexico)]. E-mail: martinez.villafane@cimav.edu.mx

    2011-01-15

    The corrosion in the reinforcement steel is a problem that diminishes the useful life of reinforced concrete structures, reside committing its structural security. In the available models to estimate the mechanical effect of the corrosion, it is assumed that the corroded steel, through the oxides that grow to its surroundings, exercises a pressure on the surrounding concrete supposing a problem of plane stress or plane strain. In this work, the problem is modeled with three-dimensional finite element starting from an experiment on a subjected cylinder to accelerated corrosion, with strain gage to measure the pressure indirectly in the interface steel-concrete. From the results obtained it can be concluded that the effect of the length of corroded steel, anodic length, has a significant effect on the magnitude of the pressure in the interface steel-concrete, fact that can be used to improve the existing models. [Spanish] La corrosion en el acero de refuerzo es un problema que disminuye la vida util en las estructuras de concreto reforzado, ademas de comprometer su seguridad estructural. En los modelos disponibles para estimar el efecto mecanico de la corrosion, se supone que el acero corroido, a traves de los oxidos que crecen a su alrededor, ejercen una presion sobre el concreto circundante suponiendo un problema de esfuerzos o deformaciones planas, En el presente trabajo, se modela el problema con elemento finito tridimensional a partir de un experimento sobre un cilindro de concreto reforzado sometido a corrosion acelerada, instrumentado para medir indirectamente la presion en la interfase acero-concreto. De los resultados obtenidos se concluye que el efecto de la longitud de acero corroido, longitud anodica, tiene un efecto significativo sobre la magnitud de la presion en la interfase acero-concreto, hecho que puede ser utilizado para mejorar los modelos existentes.

  1. La implementación de la política de abastecimiento alimentario de Bogotá en el sector mayorista de la comercialización de alimentos : restricciones y dificultades

    OpenAIRE

    Ramírez Pascagaza, Juan Daniel

    2010-01-01

    Análisis de los obstáculos que enfrenta la ejecución de la política de abastecimiento alimentario de Bogotá, por cuenta de las características de la comercialización tradicional de alimentos, en particular de su mercado mayorista. En este sentido se identifican claramente cuáles son las restricciones que enfrenta la política para eliminar la intermediación comercial, se argumenta por qué la intermediación mayorista no es el factor que más encarece los precios de los alimentos, y se puntualiza...

  2. Negative thermal expansion materials

    International Nuclear Information System (INIS)

    Evans, J.S.O.

    1997-01-01

    The recent discovery of negative thermal expansion over an unprecedented temperature range in ZrW 2 O 8 (which contracts continuously on warming from below 2 K to above 1000 K) has stimulated considerable interest in this unusual phenomenon. Negative and low thermal expansion materials have a number of important potential uses in ceramic, optical and electronic applications. We have now found negative thermal expansion in a large new family of materials with the general formula A 2 (MO 4 ) 3 . Chemical substitution dramatically influences the thermal expansion properties of these materials allowing the production of ceramics with negative, positive or zero coefficients of thermal expansion, with the potential to control other important materials properties such as refractive index and dielectric constant. The mechanism of negative thermal expansion and the phase transitions exhibited by this important new class of low-expansion materials will be discussed. (orig.)

  3. VALIDACIÓN DE UN ALGORITMO HÍBRIDO DEL PSO CON EL MÉTODO SIMPLEX Y DE TOPOLOGÍA DE EVOLUCIÓN PARAMÉTRICA

    OpenAIRE

    RODRIGO CORREA; OSCAR BEGAMBRE; JULIO C. CARRILLO E.

    2011-01-01

    Este artículo describe algunos de los aspectos más importantes relacionados con la experimentación numérica de un híbrido del algoritmo PSO (Particle Swarm Optimization) con el tradicional método simplex modificado de Nelder-Mead. El híbrido de estas dos técnicas de optimización sin restricciones se realizó con una topología que permite optimizar en cada iteración los parámetros del algoritmo PSO utilizando el método simplex modificado. Se realizaron experimentos numéricos con este algoritmo ...

  4. Expansion joints for LMFBR

    Energy Technology Data Exchange (ETDEWEB)

    Dzenus, M.; Hundhausen, W.; Jansing, W.

    1979-10-15

    This discourse recounts efforts put into the SNR-2 project; specifically the development of compensation devices. The various prototypes of these compensation devices are described and the state of development reviewed. The expansion joints were developed on the basis of specific design criteria whereby differentiation is made between expansion joints of small and large nominal diameter. Expansion joints for installation in the sodium-filled primary piping are equipped with safety bellows in addition to the actual working bellows.

  5. Cementos con cenizas volantes

    Directory of Open Access Journals (Sweden)

    Ossa M., Mauricio

    1984-03-01

    Full Text Available Almost all the studies carried out on cements with the addition of flying ash refer to their characteristics and behaviours in pastes, mortars and concretes, always in relation with Portland cement. This time, there has been developed an experimental work oriented to relate between themselves the cements with additions of flying ash and of natural puzzolan. For this there were manufactured on laboratory scale cements of both types, using the same raw materials, clinker and plaster, and as variables, different percentages of the two additions, which previously complied with the standard requisites concerning their puzzolanic (?? activities. The quality of the cements manufactured was adequate and in accord with that of Portland-puzzolanic (?? cement obtained on an industrial scale with the same clinkers, plaster and natural puzzolan (?? of this study. Later there were determined the characteristics of the experimental cements and normal mortars were prepared for carrying out physical and mechanical tests. The test results indicated that the cements with addition of flying ash (CCV require less water for normal consistency, present greater times of forging and fewer expansions in autoclave than the cements with the addition of puzzolan (CP. The hydration heats at 7 and 28 days were approximately similar for both types of cement. In normal mortars, the CCV cements showed less retraction of drying, greater retentivenness and greater fluidity (for the same quantity of water than the CP cements. In the exudation tests it was observed that this depends more on the fineness than the type of addition. Finally, the mechanical tests showed that the resistances to compression and flexotraction of the mortars with CCV cements are lesser at ages less than 14 days (about 5 to 10% at one day of age, but from then on become greater than those of mortars with CP cements, with growing differences which reach 15% in compression tests, at 120 days of age, for

  6. Convergence of mayer expansions

    International Nuclear Information System (INIS)

    Brydges, D.C.

    1986-01-01

    The tree graph bound of Battle and Federbush is extended and used to provide a simple criterion for the convergence of (iterated) Mayer expansions. As an application estimates on the radius of convergence of the Mayer expansion for the two-dimensional Yukawa gas (nonstable interaction) are obtained

  7. O-PRECISION: UNA ALTERNATIVA METODOLÓGICA DE TRABAJO CON PERSONAS CON DISCAPACIDAD FÍSICA E INTELECTUAL

    Directory of Open Access Journals (Sweden)

    Victoria Rey Niño

    2015-04-01

    Full Text Available La Clasificación Internacional del Funcionamiento, de la Discapacidad y de la Salud (CIF define la discapacidad como un término genérico que abarca deficiencias, limitaciones de la actividad y restricciones a la participación. En este caso hablamos de personas con discapacidad física e intelectual por parálisis cerebral, lo que significa que su acceso al mundo de la actividad física se encuentra en la mayoría de los casos muy restringido. Pero existe una modalidad de la orientación llamada Orientación de Precisión u O-Trail que, según la Federación Deportiva de Orientación (FEDO, ha sido adaptada para ofrecer a todos, independientemente de su sexo, edad, capacidad o discapacidad física, la oportunidad de participar en igualdad de condiciones en una típica competición de orientación. Como sugiere Arribas y Sánchez (1998: “En la actividad física podemos encontrar recursos y herramientas de intervención adecuadas a cada contexto y etapa de ciclo vital además, a través de su práctica pueden verse satisfechas determinadas necesidades e intereses personales y grupales, que pueden ser tratados desde un planteamiento educativo” . Este proyecto tiene la intención de ir más allá y pretende utilizar la Orientación de precisión como una herramienta para implementar una alternativa metodológica de trabajo a las actividades que se llevan a cabo con un colectivo de personas con discapacidad física e intelectual en la Asociación Cultural y rehabilitadora de Discapacitados Físicos de Palencia, desarrollando y estimulando sus aspectos intelectuales y sociales mediante una disciplina deportiva desconocida para ellos, con la intención de que aumente su motivación por participar.Objetivo: Implementar la O-Precisión como alternativa metodológica de trabajo con personas con discapacidad física e intelectual con el fin de desarrollar sus capacidades cognitivas y aumentar su autoestima.

  8. Teoría de restricciones aplicada a la cadena de suministros en un operador logístico de productos farmacéuticos

    OpenAIRE

    Barrero Muñoz, Diana; Guerrero Mora, Karina Elizabeth

    2013-01-01

    En las instituciones hospitalarias es fundamental el tema relacionado con los medicamentos y dispositivos médicos para la atención del paciente, por lo tanto el mecanismo de adquisición y disponibilidad de éstos productos, ha llevado a la participación masiva de operadores logísticos (Outsoursing) interviniendo áreas de la cadena de suministros, desde el punto de fabricación con el producto terminado hasta la dispensación del medicamento o dispositivo médico, para que ser usado o administrado...

  9. Métodos de optimización para el problema de ruteo de vehículos con inventarios y ventanas de tiempo duras

    Directory of Open Access Journals (Sweden)

    Eliseo Pérez Kaligari

    2015-10-01

    Full Text Available El problema estudiado considera las decisiones de ruteo de vehículos con inventarios y restricciones de ventanas de tiempo duras (IRPTW en una cadena de abastecimiento compuesta por un depósito y múltiples minoristas. Se asume un horizonte de planeación discreto y finito en donde las decisiones por optimizar son: las cantidades a aprovisionar a los minoristas y, simultáneamente, la secuencia de minoristas a visitar en cada periodo de tiempo. El sistema cuenta con un sólo vehículo de capacidad limitada, restricciones de capacidad de almacenamiento de los minoristas, y tasa de producción limitada del depósito. Se requiere satisfacer la demanda que tienen los minoristas. Se asume que los minoristas tienen demanda determinística y no homogénea. Se propone una formulación matemática basada en programación entera mixta y se estudia el impacto que tiene la configuración de las ventanas de tiempo sobre las decisiones de ruteo de vehículos con inventarios, a través de dos métodos de optimización. El primer método optimiza las decisiones de forma simultánea, mientras que el segundo método propuesto considera las decisiones de forma secuencial, lo que lo convierte en un método heurístico. Se presenta un estudio computacional con 80 instancias adaptadas de la literatura. Los resultados muestran que el método de optimización simultáneo tiene un desempeño mejor que el método heurístico de optimización secuencial generando ahorros potenciales en los costos logísticos de al menos 6%.

  10. Métodos de optimización para el problema de ruteo de vehículos con inventarios y ventanas de tiempo duras

    Directory of Open Access Journals (Sweden)

    Eliseo Pérez Kaligari

    2015-11-01

    Full Text Available El problema estudiado considera las decisiones de ruteo de vehículos con inventarios y restricciones de ventanas de tiempo duras (IRPTW en una cadena de abastecimiento compuesta por un depósito y múltiples minoristas. Se asume un horizonte de planeación discreto y finito en donde las decisiones por optimizar son: las cantidades a aprovisionar a los minoristas y, simultáneamente, la secuencia de minoristas a visitar en cada periodo de tiempo. El sistema cuenta con un sólo vehículo de capacidad limitada, restricciones de capacidad de almacenamiento de los minoristas, y tasa de producción limitada del depósito. Se requiere satisfacer la demanda que tienen los minoristas. Se asume que los minoristas tienen demanda determinística y no homogénea. Se propone una formulación matemática basada en programación entera mixta y se estudia el impacto que tiene la configuración de las ventanas de tiempo sobre las decisiones de ruteo de vehículos con inventarios, a través de dos métodos de optimización. El primer método optimiza las decisiones de forma simultánea, mientras que el segundo método propuesto considera las decisiones de forma secuencial, lo que lo convierte en un método heurístico. Se presenta un estudio computacional con 80 instancias adaptadas de la literatura. Los resultados muestran que el método de optimización simultáneo tiene un desempeño mejor que el método heurístico de optimización secuencial generando ahorros potenciales en los costos logísticos de al menos 6%.

  11. Controlled Thermal Expansion Alloys

    Data.gov (United States)

    National Aeronautics and Space Administration — There has always been a need for controlled thermal expansion alloys suitable for mounting optics and detectors in spacecraft applications.  These alloys help...

  12. Fuel Thermal Expansion (FTHEXP)

    International Nuclear Information System (INIS)

    Reymann, G.A.

    1978-07-01

    A model is presented which deals with dimensional changes in LWR fuel pellets caused by changes in temperature. It is capable of dealing with any combination of UO 2 and PuO 2 in solid, liquid or mixed phase states, and includes expansion due to the solid-liquid phase change. The function FTHEXP models fuel thermal expansion as a function of temperature, fraction of PuO 2 , and the fraction of fuel which is molten

  13. Resonant state expansions

    International Nuclear Information System (INIS)

    Lind, P.

    1993-02-01

    The completeness properties of the discrete set of bound state, virtual states and resonances characterizing the system of a single nonrelativistic particle moving in a central cutoff potential is investigated. From a completeness relation in terms of these discrete states and complex scattering states one can derive several Resonant State Expansions (RSE). It is interesting to obtain purely discrete expansion which, if valid, would significantly simplify the treatment of the continuum. Such expansions can be derived using Mittag-Leffler (ML) theory for a cutoff potential and it would be nice to see if one can obtain the same expansions starting from an eigenfunction theory that is not restricted to a finite sphere. The RSE of Greens functions is especially important, e.g. in the continuum RPA (CRPA) method of treating giant resonances in nuclear physics. The convergence of RSE is studied in simple cases using square well wavefunctions in order to achieve high numerical accuracy. Several expansions can be derived from each other by using the theory of analytic functions and one can the see how to obtain a natural discretization of the continuum. Since the resonance wavefunctions are oscillating with an exponentially increasing amplitude, and therefore have to be interpreted through some regularization procedure, every statement made about quantities involving such states is checked by numerical calculations.Realistic nuclear wavefunctions, generated by a Wood-Saxon potential, are used to test also the usefulness of RSE in a realistic nuclear calculation. There are some fundamental differences between different symmetries of the integral contour that defines the continuum in RSE. One kind of symmetry is necessary to have an expansion of the unity operator that is idempotent. Another symmetry must be used if we want purely discrete expansions. These are found to be of the same form as given by ML. (29 refs.)

  14. Expansion joints for LMFBR

    International Nuclear Information System (INIS)

    Dzenus, M.; Hundhausen, W.; Jansing, W.

    1980-01-01

    This discourse recounts efforts put into the SNR-2 project; specifically the development of compensation devices. The various prototypes of these compensation devices are described and the state of the development reviewed. Large Na (sodium)-heat transfer systems require a lot of valuable space if the component lay-out does not include compensation devices. So, in order to condense the spatial requirement as much as possible, expansion joints must be integrated into the pipe system. There are two basic types to suit the purpose: axial expansion joints and angular expansion joints. The expansion joints were developed on the basis of specific design criteria whereby differentiation is made between expansion joints of small and large nominal diameter. Expansion joints for installation in the sodium-filled primary piping are equipped with safety bellows in addition to the actual working bellows. Expansion joints must be designed and mounted in a manner to completely withstand seismic forces. The design must exclude any damage to the bellows during intermittent operations, that is, when sodium is drained the bellows' folds must be completely empty; otherwise residual solidified sodium could destroy the bellows when restarting. The expansion joints must be engineered on the basis of the following design data for the secondary system of the SNR project: working pressure: 16 bar; failure mode pressure: 5 events; failure mode: 5 sec., 28.5 bar, 520 deg. C; working temperature: 520 deg. C; temperature transients: 30 deg. C/sec.; service life: 200,000 h; number of load cycles: 10 4 ; material: 1.4948 or 1.4919; layer thickness of folds: 0.5 mm; angular deflection (DN 800): +3 deg. C or; axial expansion absorption (DN 600): ±80 mm; calculation: ASME class. The bellows' development work is not handled within this scope. The bellows are supplied by leading manufacturers, and warrant highest quality. Multiple bellows were selected on the basis of maximum elasticity - a property

  15. Accelerating the loop expansion

    International Nuclear Information System (INIS)

    Ingermanson, R.

    1986-01-01

    This thesis introduces a new non-perturbative technique into quantum field theory. To illustrate the method, I analyze the much-studied phi 4 theory in two dimensions. As a prelude, I first show that the Hartree approximation is easy to obtain from the calculation of the one-loop effective potential by a simple modification of the propagator that does not affect the perturbative renormalization procedure. A further modification then susggests itself, which has the same nice property, and which automatically yields a convex effective potential. I then show that both of these modifications extend naturally to higher orders in the derivative expansion of the effective action and to higher orders in the loop-expansion. The net effect is to re-sum the perturbation series for the effective action as a systematic ''accelerated'' non-perturbative expansion. Each term in the accelerated expansion corresponds to an infinite number of terms in the original series. Each term can be computed explicitly, albeit numerically. Many numerical graphs of the various approximations to the first two terms in the derivative expansion are given. I discuss the reliability of the results and the problem of spontaneous symmetry-breaking, as well as some potential applications to more interesting field theories. 40 refs

  16. Virial Expansion Bounds

    Science.gov (United States)

    Tate, Stephen James

    2013-10-01

    In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

  17. Conformal expansions and renormalons

    Energy Technology Data Exchange (ETDEWEB)

    Rathsman, J.

    2000-02-07

    The coefficients in perturbative expansions in gauge theories are factorially increasing, predominantly due to renormalons. This type of factorial increase is not expected in conformal theories. In QCD conformal relations between observables can be defined in the presence of a perturbative infrared fixed-point. Using the Banks-Zaks expansion the authors study the effect of the large-order behavior of the perturbative series on the conformal coefficients. The authors find that in general these coefficients become factorially increasing. However, when the factorial behavior genuinely originates in a renormalon integral, as implied by a postulated skeleton expansion, it does not affect the conformal coefficients. As a consequence, the conformal coefficients will indeed be free of renormalon divergence, in accordance with previous observations concerning the smallness of these coefficients for specific observables. The authors further show that the correspondence of the BLM method with the skeleton expansion implies a unique scale-setting procedure. The BLM coefficients can be interpreted as the conformal coefficients in the series relating the fixed-point value of the observable with that of the skeleton effective charge. Through the skeleton expansion the relevance of renormalon-free conformal coefficients extends to real-world QCD.

  18. Thermal expansion data

    International Nuclear Information System (INIS)

    Taylor, D.

    1984-01-01

    This paper gives regression data for a modified second order polynomial fitted to the expansion data of, and percentage expansions for dioxides with (a) the fluorite and antifluorite structure: AmO 2 , BkO 2 , CeO 2 , CmO 2 , HfO 2 , Li 2 O, NpO 2 , PrO 2 , PuO 2 , ThO 2 , UO 2 , ZrO 2 , and (b) the rutile structure: CrO 2 , GeO 2 , IrO 2 , MnO 2 , NbO 2 , PbO 2 , SiO 2 , SnO 2 , TeO 2 , TiO 2 and VO 2 . Reduced expansion curves for the dioxides showed only partial grouping into iso-electronic series for the fluorite structures and showed that the 'law of corresponding states' did not apply to the rutile structures. (author)

  19. Restricciones al endeudamiento: una propuesta de análisis a partir del diferencial entre el ratio de rentabilidad del activo y el coste de la deuda

    OpenAIRE

    Moral Carcedo, Julián

    2008-01-01

    En este trabajo he tratado de aproximarme al S.C.T .español dentro del contexto privatizador, incluso cuando se trate de una empresa de producción de ciencia básica, con una referencia específica a la propiedad intelectual y en un horizonte que contempla la R.S.C. La primera constatación es que este sistema apenas ha cambiado nada en los últimos diez años y exhibe los mismos cuellos de botella que se localizan precisamente en cuestiones de propiedad. No es de extrañar por lo tanto que el diag...

  20. Uniform gradient expansions

    CERN Document Server

    Giovannini, Massimo

    2015-01-01

    Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  1. Low-temperature thermal expansion

    International Nuclear Information System (INIS)

    Collings, E.W.

    1986-01-01

    This chapter discusses the thermal expansion of insulators and metals. Harmonicity and anharmonicity in thermal expansion are examined. The electronic, magnetic, an other contributions to low temperature thermal expansion are analyzed. The thermodynamics of the Debye isotropic continuum, the lattice-dynamical approach, and the thermal expansion of metals are discussed. Relative linear expansion at low temperatures is reviewed and further calculations of the electronic thermal expansion coefficient are given. Thermal expansions are given for Cu, Al and Ti. Phenomenologic thermodynamic relationships are also discussed

  2. Reflexions on the expansion of nuclear generation in Brazil

    International Nuclear Information System (INIS)

    Freitas, Juliana de Moraes Marreco de

    2006-01-01

    This article analyses the pros and cons of the nuclear generation in Brazil, involving in a large discussion the technological perspectives both economic, social and environmental. The objective is to rise the main questions about the polemical nuclear expansion in Brazil

  3. Lace expansion for dummies

    NARCIS (Netherlands)

    Bolthausen, Erwin; Van Der Hofstad, Remco; Kozma, Gady

    2018-01-01

    We show Green's function asymptotic upper bound for the two-point function of weakly self-Avoiding walk in d >4, revisiting a classic problem. Our proof relies on Banach algebras to analyse the lace-expansion fixed point equation and is simpler than previous approaches in that it avoids Fourier

  4. OPEC future capacity expansions

    International Nuclear Information System (INIS)

    Sandrea, I.

    2005-01-01

    This conference presentation examined OPEC future capacity expansions including highlights from 2000-2004 from the supply perspective and actions by OPEC; OPEC spare capacity in 2005/2006; medium-term capacity expansion and investments; long-term scenarios, challenges and opportunities; and upstream policies in member countries. Highlights from the supply perspective included worst than expected non-OPEC supply response; non-OPEC supply affected by a number of accidents and strikes; geopolitical tensions; and higher than expected demand for OPEC crude. OPEC's actions included closer relationship with other producers and consumers; capacity expansions in 2004 and 2005/2006; and OPEC kept the market well supplied with crude in 2004. The presentation also provided data using graphical charts on OPEC net capacity additions until 2005/2006; OPEC production versus spare capacity from 2003 to 2005; OPEC production and capacity to 2010; and change in required OPEC production from 2005-2020. Medium term expansion to 2010 includes over 60 projects. Medium-term risks such as project execution, financing, costs, demand, reserves, depletion, integration of Iraq, and geopolitical tensions were also discussed. The presentation concluded that in the long term, large uncertainties remain; the peak of world supply is not imminent; and continued and enhanced cooperation is essential to market stability. tabs., figs

  5. AUTO-EXPANSIVE FLOW

    Science.gov (United States)

    Physics suggests that the interplay of momentum, continuity, and geometry in outward radial flow must produce density and concomitant pressure reductions. In other words, this flow is intrinsically auto-expansive. It has been proposed that this process is the key to understanding...

  6. Vulnerabilidad social de las mujeres y la población indígena en Oaxaca, 2005: restricciones y estrategias

    Directory of Open Access Journals (Sweden)

    Rafael G. Reyes Morales

    2007-05-01

    Full Text Available La discusión sobre vulnerabilidad de las mujeres y los indígenas en el estado de Oaxaca son: la exclusión de beneficios de las políticas públicas de bienestar, el poder adquisitivo y las estrategias para superar la condición de vulnerabilidad. Los hallazgos del artículo contradicen la situación de relativa precariedad de los hogares con jefatura femenina reportada por la literatura especializada. La migración aparece como un instrumento que contribuye a la equidad de género y permite elevar la escolaridad de la población indígena.

  7. Restricciones y prejuicios en torno a las relaciones sentimentales y familiares de la comunidad esclava en tiempos de la independencia de Colombia

    Directory of Open Access Journals (Sweden)

    Roger Pita Pico

    2014-01-01

    Full Text Available e ste artículo aborda la complejidad de la vida afectiva de la población esclava durante el proceso de i ndependencia de c olombia. e n términos generales, muchas de las limitaciones establecidas durante el periodo colonial siguieron vigentes, tanto en los vínculos familiares de los esclavos como en las relaciones sentimentales entabladas con el elemento blanco. a l final, fueron muy pocos los avances en esta materia debido a la posición asumida por los amos en defensa del sistema esclavista y de sus intereses como propietarios, y a la falta de compromiso por parte de las autoridades españolas y republicanas. La crisis económica y los efectos sociales de la guerra ahondarían aún más la fragmentación de la comunidad esclava.

  8. Condiciones y restricciones al desarrollo económico-social de áreas rurales en proceso de desertificación

    Directory of Open Access Journals (Sweden)

    D. De Lima-Vidal

    2006-01-01

    Full Text Available El fenómeno de la desertificación reviste un importante papel en el entorno de los espacios desfavorecidos y frágiles de los países económicamente periféricos y dependientes. Las causas de la extensión reciente de la aridez deben ser buscadas en la superexplotación de los ecosistemas vinculados a los tratamientos antrópicos inadecuados. A través de este estudio descriptivo, las características que definen y condicionan las principales zonas desérticas o semi-desérticas del mundo son comparadas en sus dinámicas. El objetivo es comprender las bases del proceso de desertificación desde el punto de vista de la economía política rural. El análisis se apoya, principalmente, en el ecosistema semiárido brasileño, que está incluido entre las regiones más extensas del globo. En el caso de Brasil, las estructuras económicas anacrónicas de su región semiárida caracterizada por la articulación del latifundio-capital mercantil agro-exportador, son consideradas las mayores responsables por el retraso económico-social de la región, ya que absorben las capacidades de transporte, servicios y créditos para las actividades de exportación. Esas áreas secas necesitan con urgencia de nuevos enfoques económicos fundamentados en el análisis y planeamiento micro-económicos que permitan el desarrollo de políticas públicas con prioridad en la integración regional

  9. Algunas novelas de Darío Fernández-Flórez: de Zarabanda (1944 a Alta Costura (1954. Temas escabrosos en tiempos de restricciones moralistas

    Directory of Open Access Journals (Sweden)

    Montejo Gurruchaga, Lucía

    2008-06-01

    Full Text Available Dario Fernández-Flórez begins in 1944 with Zarabanda a narrative style of intellectual eroticism and inmoral atmosphere which attracted no attention. Six years later he published Lola, espejo oscuro the recollections of a high prostitute. The novel was an scandal and an immediate success. Although the topic and its treatment were odd at the time because the strict moral values which mantained Franco´s regime were ignored, the novel was published with no cuts at all. Censorship was deaf to all the voices that warned of its dangers. This had an explanation: Darío Fernández-Flórez held an important post in the Propaganda National Service. After his dismissal censors were less lenient.Darío Fernández-Flórez inicia en 1944 con Zarabanda una narrativa de erotismo intelectualizado y ambiente amoral que no tuvo ningún eco. Seis años después publicará Lola, espejo oscuro, las memorias de una prostituta de alto copete. La novela suscitó un gran escándalo y su éxito fue inmediato. Aunque el tema y su tratamiento eran inusitados en aquellos momentos porque la obra daba al traste con los estrictos valores morales que sustentaban el régimen franquista, la novela fue publicada sin recortes; la censura hizo oídos sordos a todas las voces que alertaban de su peligro. Este hecho tiene una explicación: Darío Fernández-Flórez ocupaba un cargo importante en el Servicio Nacional de Propaganda. Tras su cese, los censores serán menos benevolentes.

  10. Paciente con esquizofrenia tratado con ziprasidona + clozapina

    Directory of Open Access Journals (Sweden)

    Pol Yanguas E.

    2013-05-01

    Full Text Available P es un paciente diagnosticado de esquizofrenia, sigue en un piso tutelado un programa de rehabilitación, está medicado con clozapina 500 mg/día y ziprasidona 280 mg/ día. Padece hipercolesterolemia, tabaquismo y sus hábitos alimenticios no son buenos. La medicación que utiliza desde 2007 hasta ahora se refleja en la tabla 1. El último tratamiento se le introdujo el 7 de agosto de 2012, habiendo presentado un electro cardiograma (ECG normal, pero con ligera taquicardia ventricular y prolactinemia de 44,8 ng/ml (valores normales: 2-18 ng/ml.

  11. Expansion at Olympic Dam

    International Nuclear Information System (INIS)

    Lewis, C.

    1997-01-01

    The Olympic Dam orebody is the 6th largest copper and the single largest uranium orebody in the world. Mine production commenced in June 1988, at an annual production rate of around 45,000 tonnes of copper and 1,000 tonnes of uranium. Western Mining Corporation announced in 1996 a proposed $1.25 billion expansion of the Olympic Dam operation to raise the annual production capacity of the mine to 200,000 tonnes of copper, approximately 3,700 tonnes of uranium, 75,000 ounces of gold and 950,000 ounces of silver by 2001. Further optimisation work has identified a faster track expansion route, with an increase in the capital cost to $1.487 billion but improved investment outcome, a new target completion date of end 1999, and a new uranium output of 4,600 tonnes per annum from that date

  12. Financing electricity expansion

    International Nuclear Information System (INIS)

    Hyman, L.S.

    1994-01-01

    Expansion of electricity supply is associated with economic development. The installation and enlargement of power systems in developing countries entails a huge financial burden, however. Energy consumers in such countries must pay not only for supplies but for the cost of raising the capital for expansion on the international markets. Estimates are presented for the capital expenditure for electricity supply over the period 1990 to 2020 for the major world regions, using approximations for the cost of plant and capital and for the returns earned. These data lead to the conclusion that the five regions with the lowest per capita incomes are those which will need the major part of the capital expenditure and the highest percentage of external finance. (6 tables) (UK)

  13. Bigravity from gradient expansion

    International Nuclear Information System (INIS)

    Yamashita, Yasuho; Tanaka, Takahiro

    2016-01-01

    We discuss how the ghost-free bigravity coupled with a single scalar field can be derived from a braneworld setup. We consider DGP two-brane model without radion stabilization. The bulk configuration is solved for given boundary metrics, and it is substituted back into the action to obtain the effective four-dimensional action. In order to obtain the ghost-free bigravity, we consider the gradient expansion in which the brane separation is supposed to be sufficiently small so that two boundary metrics are almost identical. The obtained effective theory is shown to be ghost free as expected, however, the interaction between two gravitons takes the Fierz-Pauli form at the leading order of the gradient expansion, even though we do not use the approximation of linear perturbation. We also find that the radion remains as a scalar field in the four-dimensional effective theory, but its coupling to the metrics is non-trivial.

  14. Expansion of magnetic clouds

    International Nuclear Information System (INIS)

    Suess, S.T.

    1987-01-01

    Magnetic clouds are a carefully defined subclass of all interplanetary signatures of coronal mass ejections whose geometry is thought to be that of a cylinder embedded in a plane. It has been found that the total magnetic pressure inside the clouds is higher than the ion pressure outside, and that the clouds are expanding at 1 AU at about half the local Alfven speed. The geometry of the clouds is such that even though the magnetic pressure inside is larger than the total pressure outside, expansion will not occur because the pressure is balanced by magnetic tension - the pinch effect. The evidence for expansion of clouds at 1 AU is nevertheless quite strong so another reason for its existence must be found. It is demonstrated that the observations can be reproduced by taking into account the effects of geometrical distortion of the low plasma beta clouds as they move away from the Sun

  15. IKEA's International Expansion

    OpenAIRE

    Harapiak, Clayton

    2013-01-01

    This case concerns a global retailing firm that is dealing with strategic management and marketing issues. Applying a scenario of international expansion, this case provides a thorough analysis of the current business environment for IKEA. Utilizing a variety of methods (e.g. SWOT, PESTLE, McKinsey Matrix) the overall objective is to provide students with the opportunity to apply their research skills and knowledge regarding a highly competitive industry to develop strategic marketing strateg...

  16. Symmetric eikonal expansion

    International Nuclear Information System (INIS)

    Matsuki, Takayuki

    1976-01-01

    Symmetric eikonal expansion for the scattering amplitude is formulated for nonrelativistic and relativistic potential scatterings and also for the quantum field theory. The first approximations coincide with those of Levy and Sucher. The obtained scattering amplitudes are time reversal invariant for all cases and are crossing symmetric for the quantum field theory in each order of approximation. The improved eikonal phase introduced by Levy and Sucher is also derived from the different approximation scheme from the above. (auth.)

  17. Series expansions without diagrams

    International Nuclear Information System (INIS)

    Bhanot, G.; Creutz, M.; Horvath, I.; Lacki, J.; Weckel, J.

    1994-01-01

    We discuss the use of recursive enumeration schemes to obtain low- and high-temperature series expansions for discrete statistical systems. Using linear combinations of generalized helical lattices, the method is competitive with diagrammatic approaches and is easily generalizable. We illustrate the approach using Ising and Potts models. We present low-temperature series results in up to five dimensions and high-temperature series in three dimensions. The method is general and can be applied to any discrete model

  18. El portafolio docente a escrutinio: sus posibilidades y restricciones en la formación y evaluación del profesorado.

    Directory of Open Access Journals (Sweden)

    Frida Díaz Barriga Arceo

    2010-07-01

    Full Text Available A pesar del gran entusiasmo y amplia difusión que han despertado los portafolios como recurso innovador en la evaluación y formación del profesorado, debe realizarse un análisis de su sentido y alcances, para evitar su empleo indiscriminado y poco crítico. En este artículo se revisa el surgimiento y supuestos educativos de los portafolios docentes, así como algunos estudios que dan cuenta de su potencialidad como recurso de evaluación auténtica y reflexión sobre la propia identidad y práctica educativa de los docentes en formación. Asimismo, se revisan una serie de críticas y notas precautorias respecto a su empleo, sobre todo cuando se pretende su aplicación como instrumento estandarizado a gran escala. Se concluye que su mayor potencial reside en promover la autoevaluación reflexiva de los profesores y en la posibilidad de impulsar un cambio en la cultura de la evaluación en las instituciones educativas. Al mismo tiempo, el gran riesgo consiste en la proliferación de una mirada exclusivamente técnica y sesgada, centrada en los instrumentos de calificación, con poco fundamento teórico e investigación empírica.

  19. Expansions for Coulomb wave functions

    NARCIS (Netherlands)

    Boersma, J.

    1969-01-01

    In this paper we derive a number of expansions for Whittaker functions, regular and irregular Coulomb wave functions. The main result consists of a new expansion for the irregular Coulomb wave functions of orders zero and one in terms of regular Coulomb wave functions. The latter expansions are

  20. De la “maldición de la basura” y restricciones institucionales: una evaluación ambiental ex ante al desperdicio Nortecaucano

    Directory of Open Access Journals (Sweden)

    Cortés Landázury Raúl

    2012-05-01

    Full Text Available En el análisis de la brecha entre anhelos y realizaciones en materia de desarrollo sostenible en América latina, la mayoría de los argumentos se inclinan por interpretaciones de corte económico ortodoxo. Sin embargo, si se consideran los problemas ambientales anteriores e independientes del paradigma económico de turno, las razones para la persistencia y universalidad de estos fenómenos no deben buscarse meramente en este tipo de dimensión. Tal es el caso de la disposición final de residuos sólidos en el norte del departamento del Cauca, donde la eficiencia técnica en torno a la solución del problema traba con elementos de tipo ético y cultural que, quizás, se entiendan mejor desde la economía política. Este documento expone algunas interpretaciones del asunto, abordando la problemática a partir de la idea de fallo de coordinación derivado de la incongruencia entre mecanismos de decisión y acción colectiva. Por este motivo, se describe el contexto de la problemática, indicando el protagonismo de los factores de presión, el papel de las instituciones involucradas, los lineamientos generales de la solución técnica y la percepción de los actores a través de la medición económica de sus preferencias, y finalmente se concluye.

  1. Radial expansion and multifragmentation

    International Nuclear Information System (INIS)

    Angelique, J.C.; Bizard, G.; Bougault, R.; Brou, R.; Buta, A.; Colin, J.; Cussol, D.; Durand, D.; Kerambrun, A.; Le Brun, C.; Lecolley, J.F.; Lopez, O.; Louvel, M.; Meslin, C.; Nakagawa, T.; Patry, J.P.; Peter, J.; Popescu, R.; Regimbart, R.; Steckmeyer, J.C.; Tamain, B.; Vient, E.; Yuasa-Nakagawa, K.; Wieloch, A.

    1998-01-01

    The light systems 36 Ar + 27 Al and 64 Zn + nat Ti were measured at several bombarding energies between ∼ 35 and 95 MeV/nucleon. It was found that the predominant part of the cross section is due to binary collisions. In this paper the focus is placed on the properties of the quasi-projectile nuclei. In the central collisions the excitation energies of the quasi-projectile reach values exceeding largely 10 MeV/nucleon. The slope of the high energy part of the distribution can give only an upper limit of the apparent temperature (the average temperature along the decay chain). The highly excited quasi-projectile may get rapidly fragmented rather than sequentially. The heavy fragments are excited and can emit light particles (n, p, d, t, 3 He, α,...) what perturbs additionally the spectrum of these particles. Concerning the expansion energy, one can determine the average kinetic energies of the product (in the quasi-projectile-framework) and compare with simulation values. To fit the experimental data an additional radial expansion energy is to be considered. The average expansion energy depends slightly on the impact parameter but it increases with E * / A, ranging from 0.4 to 1,2 MeV/nucleon for an excitation energy increasing from 7 to 10.5 MeV/nucleon. This collective radial energy seems to be independent of the fragment mass, what is possibly valid for the case of larger quasi-projectile masses. The origin of the expansion is to be determined. It may be due to a compression in the interaction zone at the initial stage of the collision, which propagates in the quasi-projectile and quasi-target, or else, may be due, simply, to the increase of thermal energy leading to a rapid fragment emission. The sequential de-excitation calculation overestimates light particle emission and consequently heavy residues, particularly, at higher excitation energies. This disagreement indicates that a sequential process can not account for the di-excitation of very hot nuclei

  2. Rethinking expansive learning

    DEFF Research Database (Denmark)

    Kolbæk, Ditte; Lundh Snis, Ulrika

    Abstract: This paper analyses an online community of master’s students taking a course in ICT and organisational learning. The students initiated and facilitated an educational design for organisational learning called Proactive Review in the organisation where they are employed. By using an online...... discussion forum on Google groups, they created new ways of reflecting and learning. We used netnography to select qualitative postings from the online community and expansive learning concepts for data analysis. The findings show how students changed practices of organisational learning...

  3. Load regulating expansion fixture

    International Nuclear Information System (INIS)

    Wagner, L.M.; Strum, M.J.

    1998-01-01

    A free standing self contained device for bonding ultra thin metallic films, such as 0.001 inch beryllium foils is disclosed. The device will regulate to a predetermined load for solid state bonding when heated to a bonding temperature. The device includes a load regulating feature, whereby the expansion stresses generated for bonding are regulated and self adjusting. The load regulator comprises a pair of friction isolators with a plurality of annealed copper members located there between. The device, with the load regulator, will adjust to and maintain a stress level needed to successfully and economically complete a leak tight bond without damaging thin foils or other delicate components. 1 fig

  4. Ganho de peso nos pacientes portadores de mielomeningocele após tratamento com prótese vertical expansível de titânio para costela Aumento de peso en pacientes con mielomeningocele después del tratamiento con la prótesis vertical expansible de titanio para costilla Weight gain in patients with myelomeningocele after treatment with vertical expandable prosthetic titanium rib

    Directory of Open Access Journals (Sweden)

    Rafael Marques Ielpo

    2012-09-01

    Full Text Available OBJETIVO: Avaliar o ganho de peso e a variação do estado nutricional dos pacientes portadores de mielomeningocele torácica após o uso da prótese vertical expansível de titânio (VEPTR como opção para tratamento sem fusão da coluna vertebral. MÉTODOS: Estudo retrospectivo de oito pacientes (com média de idade de 5,3 anos; variando de 3,6 a 7,6 anos no momento da cirurgia inicial, portadores de mielomeningocele torácica que apresentavam escoliose, medida pelo método de Cobb, superior a 40º e cifose superior a 80º, tratados com VEPTR pelo grupo de Escoliose da AACD de São Paulo. Foram analisados os pesos, desvio-padrão em que cada paciente se encontrava na tabela idade versus peso referência da OMS e valores angulares da cifose, no pré-operatório, pós-operatório imediato e pós-operatório tardio. RESULTADOS: Houve ganho absoluto de peso em todos os pacientes, com média de 8,7 kg (variando de 3 a 20 kg. Seis pacientes (75% apresentaram ganho de peso e aumento do valor do desvio padrão, traduzindo-se em aproximação de seu peso com relação à mediana considerada normal da curva idade versus peso referência após o início do tratamento com VEPTR. CONCLUSÃO: O ganho de peso absoluto observado não foi acompanhado de melhora do estado nutricional e não houve relação entre correção da cifose e ganho de peso.OBJETIVO: Evaluar la ganancia de peso y el cambio en el estado nutricional de los pacientes con mielomeningocele torácico después de usar la prótesis vertical expandible de titanio (VEPTR como una opción para el tratamiento sin la fusión de la columna vertebral. MÉTODOS: Estudio retrospectivo de ocho pacientes (edad media de 5,3 años, entre 3,6 y 7,6 años en el momento de la cirugía inicial, con mielomeningocele torácico que tenían escoliosis , medida por el método de Cobb, con valores superiores a 40 º y cifosis mayores de 80 º, tratados con VEPTR en el Grupo de Escoliosis de la AACD en São Paulo. Se

  5. Thermal expansion of granite rocks

    International Nuclear Information System (INIS)

    Stephansson, O.

    1978-04-01

    The thermal expansion of rocks is strongly controlled by the thermal expansion of the minerals. The theoretical thermal expansion of the Stripa Granite is gound to be 21 . 10 -6 [deg C] -1 at 25 deg C and 38 . 10 -6 [deg C] -1 at 400 deg C. The difference in expansion for the rock forming minerals causes micro cracking at heating. The expansion due to micro cracks is found to be of the same order as the mineral expansion. Most of the micro cracks will close at pressures of the order of 10 - 20 MPa. The thermal expansion of a rock mass including the effect of joints is determined in the pilot heater test in the Stripa Mine

  6. Desarrollo de un modelo generalizado para realimentación de fuerza y torque en cirugía cardiotorácica robótica mínimamente invasiva: determinación de condiciones y restricciones Development of a generalized model for force and torque feedback in robotic minimally invasive cardiothoracic surgery: identification of conditions and restrictions

    Directory of Open Access Journals (Sweden)

    Vera Pérez

    2011-07-01

    Full Text Available INTRODUCCIÓN: los procedimientos de cirugía cardiotorácica mínimamente invasiva (MICS, su sigla en Inglés buscan reducir las complicaciones de las grandes disecciones. No obstante, ante la falta de contacto directo con el tejido por parte del cirujano, éste recibe una sensación parcial de tacto y fuerza, lo que puede originar errores de procedimiento, inadecuada fuerza aplicada al tejido y fatiga durante el acto quirúrgico. La inclusión de dispositivos robóticos con la técnica MICS ha potencializado las habilidades del cirujano para la manipulación de los tejidos, y aunque los desarrollos del mercado no cuentan aún con retroalimentación táctil, se trabaja en prototipos robóticos que incorporan realimentación de fuerza y torque. OBJETIVO: proponer las condiciones y restricciones relacionadas con la incorporación de realimentación de fuerza y torque en MICS robótica, aplicables a diferentes configuraciones de manipuladores, y analizar la implementación de dichas condiciones en un simulador quirúrgico. MATERIAL Y MÉTODOS: partiendo del análisis de necesidades durante procedimientos cardiotorácicos y las condiciones de cirugía mínimamente invasiva, se identificaron los requerimientos para garantizar reflexión de fuerza y se realizó un análisis matemático de dichas consideraciones. Finalmente, se verificaron los análisis matemáticos mediante técnicas de modelización y simulación utilizando la plataforma computacional Matlab®. RESULTADOS: se argumentaron tres tipos de consideraciones: a Cinemático: la existencia de un punto fijo, las formas de garantizarlo durante procedimientos MICS robóticos, y las trayectorias de movimiento que el manipulador sigue en aplicaciones de cirugía cardiotorácica; b Dinámico: la repercusión de fuerzas externas en el manipulador y la manera de considerarlas en el desarrollo de controladores que permitan al cirujano percibir una sensación de contacto con el tejido; c Sensorial

  7. Provincial hydro expansions

    Energy Technology Data Exchange (ETDEWEB)

    Froschauer, K J

    1993-01-01

    A study of the development of five provincial hydroelectric utilities in Canada indicates that power companies and the state invited manufacturers to use hydroelectricity and natural resources in order to diversify provincial economies. These hydro expansions also show that utilities and government designed hydro projects to serve continental requirements; serving both objectives became problematic. It is argued that when the Canadian state and firms such as utilities use hydro expansions to serve both continentalism and industrialization, then at best they foster dependent industrialization and staple processing. At worst, they overbuild the infrastructure to generate provincial surplus energy for continental, rather than national, integration. Hydro developments became subject to state intervention in Canada mainly through the failures of private utilities to provide power for the less-lucrative industrial markets within provincial subregions. Although the state and utilities invited foreign firms to manufacture hydro equipment within the provinces and others to use electricity to diversify production beyond resource processing, such a diversification did not occur. Since 1962, ca 80% of industrial energy was used to semi-process wood-derived products, chemicals, and metals. The idea for a national power network became undermined by interprovincial political-economic factors and since 1963, the federal national/continential power policy prevailed. 187 refs., 6 figs., 52 tabs.

  8. Measuring of tube expansion

    International Nuclear Information System (INIS)

    Vogeleer, J. P.

    1985-01-01

    The expansion of the primary tubes or sleeves of the steam generator of a nuclear reactor plant are measured while the tubes or sleeves are being expanded. A primary tube or sleeve is expanded by high pressure of water which flows through a channel in an expander body. The water is supplied through an elongated conductor and is introduced through a connector on the shank connected to the conductor at its outer end. A wire extends through the mandrel and through the conductor to the end of the connector. At its inner end the wire is connected to a tapered pin which is subject to counteracting forces produced by the pressure of the water. The force on the side where the wire is connected to the conductor is smaller than on the opposite side. The tapered pin is moved in the direction of the higher force and extrudes the wire outwardly of the conductor. The tapered surface of the tapered pin engages transverse captive plungers which are maintained in engagement with the expanding tube or sleeve as they are moved outwardly by the tapered pin. The wire and the connector extend out of the generator and, at its outer end, the wire is connected to an indicator which measures the extent to which the wire is moved by the tapered pin, thus measuring the expansion of the tube or sleeve as it progresses

  9. Videojuego con Realidad Virtual

    OpenAIRE

    González Mora, César

    2017-01-01

    El objetivo del proyecto es el desarrollo de un videojuego deportivo que utilice realidad mixta. El videojuego se podrá utilizar con dispositivos de tipo cardboard, y utilizará realidad aumentada para la interacción del jugador con el videojuego. En el desarrollo se utilizará el motor Unity para conseguir una aplicación multiplataforma, y la librería Vuforia para implementar realidad mixta.

  10. Sistemas integrados con Arduino

    OpenAIRE

    EL YAKOUTI, MOHAMMED

    2017-01-01

    Design of a robot prototype remotely controllable from Bluetooth using Arduino. Control and testing of sensors and events interacting with Arduino and Bluetooth. Diseño de un prototipo de robot controlable remotamente con Bluetooth utilizando Arduino. Control y verificación de los sensores y eventos que interactúan mediante el Arduino y el Bluetooth. El Yakouti, M. (2017). Sistemas integrados con Arduino. http://hdl.handle.net/10251/89274. TFGM

  11. Thermal expansion of coking coals

    Energy Technology Data Exchange (ETDEWEB)

    Orlik, M.; Klimek, J. (Vyzkumny a Zkusebni Ustav Nova Hut, Ostrava (Czechoslovakia))

    1992-12-01

    Analyzes expansion of coal mixtures in coke ovens during coking. Methods for measuring coal expansion on both a laboratory and pilot plant scale are comparatively evaluated. The method, developed, tested and patented in Poland by the Institute for Chemical Coal Processing in Zabrze (Polish standard PN-73/G-04522), is discussed. A laboratory device developed by the Institute for measuring coal expansion is characterized. Expansion of black coal from 10 underground mines in the Ostrava-Karvina coal district and from 9 coal mines in the Upper Silesia basin in Poland is comparatively evaluated. Investigations show that coal expansion reaches a maximum for coal types with a volatile matter ranging from 20 to 25%. With increasing volatile matter in coal, its expansion decreases. Coal expansion increases with increasing swelling index. Coal expansion corresponds with coal dilatation. With increasing coal density its expansion increases. Coal mixtures should be selected in such a way that their expansion does not cause a pressure exceeding 40 MPa. 11 refs.

  12. Identity Expansion and Transcendence

    Directory of Open Access Journals (Sweden)

    William Sims Bainbridge

    2014-05-01

    Full Text Available Emerging developments in communications and computing technology may transform the nature of human identity, in the process rendering obsolete the traditional philosophical and scientific frameworks for understanding the nature of individuals and groups.  Progress toward an evaluation of this possibility and an appropriate conceptual basis for analyzing it may be derived from two very different but ultimately connected social movements that promote this radical change. One is the governmentally supported exploration of Converging Technologies, based in the unification of nanoscience, biology, information science and cognitive science (NBIC. The other is the Transhumanist movement, which has been criticized as excessively radical yet is primarily conducted as a dignified intellectual discussion within a new school of philosophy about human enhancement.  Together, NBIC and Transhumanism suggest the immense transformative power of today’s technologies, through which individuals may explore multiple identities by means of online avatars, semi-autonomous intelligent agents, and other identity expansions.

  13. Investigando con personas con dificultades de aprendizaje

    Directory of Open Access Journals (Sweden)

    Borja González Luna

    2013-12-01

    Full Text Available El artículo muestra los orígenes de lo que Walmsley (2008 denomina «investigación inclusiva». Para comprender qué se entiende por investigación inclusiva tenemos que remontarnos a los debates epistemológicos sobre las metodologías cuantitativas y cualitativas, acontecidos en la década de los 90, en torno a la revista Disability & Society. A partir de una síntesis de dichos debates, focalizados en el ámbito de la «discapacidad intelectual y del desarrollo», se exponen dos estrategias de colaboración con dicha población: a una aproximación etnográfica (de trabajo grupal, y b una aproximación biográfica (de trabajo individual. A continuación se esboza un posible diseño de trabajo de campo que intenta superar el paradigma cualitativo «clásico» con el objetivo de incluir a dicho colectivo más allá del rol de «sujetos de la investigación». Para finalizar se recoge el debate sobre la accesibilidad de los resultados de la investigación a los participantes en dichas investigaciones, y con ello la necesaria innovación en el ámbito de las «devoluciones» de los resultados, cuando se trata de incluir a personas que presentan limitaciones para la comprensión del lenguaje abstracto oral y/o escrito.

  14. Conteo de personas con un sensor RGBD comercial

    Directory of Open Access Journals (Sweden)

    M. Castrillón-Santan

    2014-07-01

    Full Text Available Resumen: En este trabajo se demuestra que la información de profundidad proporcionada por una cámara RGBD comercial de bajo coste, es una fuente fiable de datos para realizar de forma robusta el conteo automático de personas. La adopción de una configuración de vista cenital reduce la complejidad del problema, al mismo tiempo que permite preservar la privacidad de las personas moni- torizadas. Para llevar a cabo el estudio experimental se han considerado dos técnicas propias del campo de análisis de imágenes 2D trasladadas al contexto de imágenes de profundidad. Las pruebas evaluaron su rendimiento con v́ıdeos reales sin restricciones de iluminación, incluyendo episodios de iluminación cambiante o muy baja. En este conjunto experimental se realizó la detección, seguimiento y análisis de patrones de comportamiento de las personas que cruzaban el campo de visión. Los resultados obtenidos alcanzan una tasa de acierto próxima al 95%, superando los obtenidos con técnicas actuales basadas exclusivamente en información visual. Estos resultados sugieren la utilidad del uso de información de profundidad en esta tarea particular. Abstract: In this paper, we prove that depth information provided by a consumer depth camera is a reliable data source to perform ro- bust people counting. The adoption of a top view configuration reduces the space problem complexity for this task, while pre- serving privacy. Two different background subtraction approaches for color images are transferred to this context and tested in real video to perform detection, tracking, and behavioral pat- terns analysis of subjects crossing the field of view. The results achieved in an experimental setup with real video reported a TPR over 95%, beating robust GMM background subtraction based only on the visual cue. The results suggest the benefits of the depth cue for this particular task. Palabras clave: Conteo de personas, c

  15. Thermal expansion of beryllium oxide

    International Nuclear Information System (INIS)

    Solodukhin, A.V.; Kruzhalov, A.V.; Mazurenko, V.G.; Maslov, V.A.; Medvedev, V.A.; Polupanova, T.I.

    1987-01-01

    Precise measurements of temperature dependence of the coefficient of linear expansion in the 22-320 K temperature range on beryllium oxide monocrystals are conducted. A model of thermal expansion is suggested; the range of temperature dependence minimum of the coefficient of thermal expansion is well described within the frames of this model. The results of the experiment may be used for investigation of thermal stresses in crystals

  16. Tratamento da escoliose em crianças com paralisia cerebral utilizando a prótese vertical expansível de titânio para costela (VEPTR Tratamiento de la escoliosis en niños con parálisis cerebral mediante la prótesis vertical expansible de titanio para las costillas (VEPTR Treatment of scoliosis in children with cerebral palsy using the vertical expandable prosthetic titanium rib (VEPTR

    Directory of Open Access Journals (Sweden)

    Kiyomori de Quental Tyba

    2011-01-01

    Full Text Available OBJETIVO: Avaliar o uso da prótese vertical expansível de titânio (VEPTR como opção de tratamento inicial da escoliose em crianças de baixa idade portadoras de paralisia cerebral. MÉTODOS: Foram avaliados 10 pacientes portadores de paralisia cerebral (PC tratados com VEPTR pelo grupo de escoliose da AACD de São Paulo. Caracterizavam-se por imaturidade esquelética e escoliose progressiva; sem deformidade grave no plano sagital. Realizamos avaliação da curva pelo método de Cobb no pré e pós-operatório e após dois anos de seguimento. RESULTADOS: A correção obtida com o uso do VEPTR no pós-operatório imediato foi em média de 41,4% nas radiografias iniciais sem tração (p = 0,005 e 9,1% (p = 0,055 nas radiografias com tração. Após quatro meses de pós-operatório mantiveram-se ganhos de 27,2% com relação ao início. Houve correção da obliquidade pélvica de 10,2º no pré-operatório para 5,4º em média (p = 0,007. As complicações ocorreram em seis pacientes (60% e em apenas um paciente foi necessária a retirada do VEPTR. CONCLUSÃO: O VEPTR é um método que obteve correção significativa no tratamento provisório das escolioses na PC, apesar de frequentes complicações de baixa morbidade.OBJETIVO: Evaluar el uso de la prótesis vertical expansible de titanio (VEPTR como opción de tratamiento inicial para la escoliosis en niños pequeños con parálisis cerebral. MÉTODOS: 10 pacientes con parálisis cerebral (PC fueron evaluados y tratados con VEPTR por el grupo de escoliosis de la AACD en Sao Paulo. Caracterizados por escoliosis progresiva inmadurez esquelética, sin deformidad grave en el plano sagital. Se evaluó la curva por el método de Cobb en el preoperatorio, posoperatorio, y después de dos años de seguimiento. RESULTADOS: LA CORRECCIón, obtenida con el uso de VEPTR en el posoperatorio inmediato, fue en promedio 41,4% en relación a las radiografías iniciales sin tracción (p = 0,005 y 9,1% (p = 0

  17. Inversor Resonante de Tres Elementos L-LC con Caracteristica Cortocircuitable para Aplicaciones de Calentamiento por Induccion

    Science.gov (United States)

    Espi Huerta, Jose Miguel

    Los generadores de calentamiento por induccion son puentes inversores con carga resonante, cuya mision es basicamente crear una corriente sinusoidal de gran amplitud sobre la "bobina de caldeo", que forma parte del tanque resonante. En el interior de esta bobina se introduce la pieza que se desea calentar. EI campo magnetico creado induce corrientes superficiales (corrientes de Foucault) sobre la pieza, que producen su calentamiento. Los tanques resonantes (tambien llamados osciladores) utilizados en la actualidad son el resonante serie y el resonante paralelo. Aunque ya desde hace algun tiempo se vienen construyendo generadores de alta potencia basados en estos dos osciladores, el exito nunca ha. sido completo en ninguno de los dos casos. Tal y como se explica en la introduccion de esta memoria, los puentes inversores utilizados deben operar sobre una carga inductiva (corriente retrasada) para evitar el fenomeno de la recuperacion inversa de sus diodos y la consiguiente ruptura de los transistores. De la restriccion topologica anterior se deduce que el generador paralelo debe conmutar a frecuencias inferiores a la resonancia, y el serie a frecuencias superiores. A esta restriccion topologica hay que unir otra que es exclusiva del calentamiento por induccion: La corriente por la bobina de caldeo debe ser sinusoidal. De no ser asi, resultaria imposible disponer toda la potencia de calentamiento sobre la pieza en el espesor requerido por la aplicacion. Como consecuencia, los inversores no pueden operar por debajo de la frecuencia de resonancia del oscilador, pues en ese caso se amplifican los armonicos de orden superior de la tension/corriente de entrada situados sobre la resonancia, con la consiguiente distorsion de la corriente de salida. La conjuncion de las dos restricciones anteriores obligan al inversor paralelo a funcionar a la frecuencia de resonancia del oscilador. Esto imposibilita un control por variacion de frecuencia, regulandose la potencia desde la

  18. Desarrollo del módulo para administración de proyectos utilizando la plataforma libre ODOO, aplicando el método cadena crítica basado en la teoría de restricciones del Dr. Eliyahu Goldratt.

    OpenAIRE

    Mogrovejo Baque, Mercedes; Ormaza Acosta, Christopher

    2015-01-01

    En la presente investigación se desarrolló sistema de administración de proyectos basado en cadena crítica del Dr Eliyahu Goldratt fundamentado en la teoría de restricciones, sobre la plataforma de código abierto Odoo, esta teoría permite identificar y gestionar puntualmente 3 problemas que se dan en la administración de proyectos, estos son: el síndrome del estudiante, la ley de parkinson, y el contexto de multitareas. In this research was developed a project management system based on cr...

  19. Giochiamo con i robot

    Directory of Open Access Journals (Sweden)

    Andrea Bonarini

    2009-01-01

    Full Text Available "Giochiamo con i robot" e' un laboratorio interattivo per grandi e piccini realizzato per l'edizione 2007 del Festival della Scienza di Genova. Lungo un percorso che va dalla telerobotica alla robotica evolutiva, il laboratorio sviluppa il tema di dare intelligenza ai robot. Questo percorso, le cui tappe sono le varie installazioni, si conclude nella "bottega" dove e' possibile costruire e programmare i propri robot o smontare e modificare quelli esposti durante il percorso didattico. I visitatori sono coinvolti in attivita' ludiche grazie alle quali possonoentrare in contatto con alcune delle idee potenti della robotica,

  20. disegnare con ... Alberto Pratelli

    Directory of Open Access Journals (Sweden)

    Roberto Mingucci

    2017-12-01

    Full Text Available Con questa breve intervista ad Alberto Pratelli, (non a caso scelto per aprire questa nuova rubrica intendia-mo inaugurare un dialogo con personalità significati-ve del Disegno di Architettura, che consenta riflessioni dedicate alle sue varie dimensioni, oggi più che mai da approfondire. La suggestione a farlo, viene da un’idea di Pablo Rodri-guez Navarro ed abbiamo quindi pensato di avviarla proprio in questo numero, che Pablo ha accettato di curare su un tema a lui particolarmente caro.

  1. Renormalization group and Mayer expansions

    International Nuclear Information System (INIS)

    Mack, G.

    1984-02-01

    Mayer expansions promise to become a powerful tool in exact renormalization group calculations. Iterated Mayer expansions were sucessfully used in the rigorous analysis of 3-dimensional U(1) lattice gauge theory by Goepfert and the author, and it is hoped that they will also be useful in the 2-dimensional nonlinear sigma-model, and elsewhere. (orig.)

  2. Isotropic Negative Thermal Expansion Metamaterials.

    Science.gov (United States)

    Wu, Lingling; Li, Bo; Zhou, Ji

    2016-07-13

    Negative thermal expansion materials are important and desirable in science and engineering applications. However, natural materials with isotropic negative thermal expansion are rare and usually unsatisfied in performance. Here, we propose a novel method to achieve two- and three-dimensional negative thermal expansion metamaterials via antichiral structures. The two-dimensional metamaterial is constructed with unit cells that combine bimaterial strips and antichiral structures, while the three-dimensional metamaterial is fabricated by a multimaterial 3D printing process. Both experimental and simulation results display isotropic negative thermal expansion property of the samples. The effective coefficient of negative thermal expansion of the proposed models is demonstrated to be dependent on the difference between the thermal expansion coefficient of the component materials, as well as on the circular node radius and the ligament length in the antichiral structures. The measured value of the linear negative thermal expansion coefficient of the three-dimensional sample is among the largest achieved in experiments to date. Our findings provide an easy and practical approach to obtaining materials with tunable negative thermal expansion on any scale.

  3. Renormalization group and mayer expansions

    International Nuclear Information System (INIS)

    Mack, G.

    1984-01-01

    Mayer expansions promise to become a powerful tool in exact renormalization group calculations. Iterated Mayer expansions were sucessfully used in the rigorous analysis of 3-dimensional U (1) lattice gauge theory by Gopfert and the author, and it is hoped that they will also be useful in the 2-dimensional nonlinear σ-model, and elsewhere

  4. On summation of perturbation expansions

    International Nuclear Information System (INIS)

    Horzela, A.

    1985-04-01

    The problem of the restoration of physical quantities defined by divergent perturbation expansions is analysed. The Pad'e and Borel summability is proved for alternating perturbation expansions with factorially growing coefficients. The proof is based on the methods of the classical moments theory. 17 refs. (author)

  5. Conversando con Oriol Bohigas

    OpenAIRE

    Redondo Domínguez, Ernesto; Moya Sala, Joaquim

    2015-01-01

    [EN] Interview with Oriol Bohigas [ES] Entrevista con Oriol Bohigas Redondo Domínguez, E.; Moya Sala, J. (2015). Conversando con… Oriol Bohigas. EGA. Revista de Expresión Gráfica Arquitectónica. 20(26):22-35. doi:10.4995/ega.2015.4061 22 35 20 26

  6. DR Con o:

    African Journals Online (AJOL)

    which could fall under the Ugandan influence. The con-. flict in the ..... The Congolese people and international community within SADC, the AU ..... ments and make peace among themselves. However, one ... friends overnight.There is a great ...

  7. fertilizada con diferentes abonos

    Directory of Open Access Journals (Sweden)

    Jorge Alberto Elizondo-Salazar

    2007-01-01

    Full Text Available Producción y calidad de la biomasa de morera (Morus alba fertilizada con diferentes abonos. Se llevó a cabo un experimento en la Estación Experimental “Alfredo Volio Mata” de la Universidad de Costa Rica con el fi n de evaluar la aplicación de 150 kg de N/ha/año proveniente de dos abonos orgánicos: lombriabono y compostaje; y de un fertilizante químico, sobre la producción y calidad de la biomasa de morera. El periodo experimental comprendió un ciclo de 12 meses, iniciando en julio del 2003 y fi nalizando en julio del 2004. Se utilizó una plantación de morera de 12 años de establecida con una densidad de siembra de 27.777 plantas/ ha. Se empleó un diseño de bloques completos al azar con cuatro tratamientos: dos abonos orgánicos, nitrato de amonio (33,5% N y un control. Las plantas se podaron a 0,6 m sobre el nivel del suelo al inicio del ensayo. Durante el periodo experimental, las plantas fueron podadas consecutivamente cada 90 días. Las hojas y los tallos fueron separados y analizados para determinar el contenido de materia seca y proteína cruda. La producción de materia seca fue 23% superior y el contenido de proteína cruda fue signifi cativamente mayor con el nitrógeno químico, mientras que el contenido de materia seca fue menor. No se encontraron diferencias signifi cativas entre el tratamiento control y los tratamientos orgánicos.

  8. Review: Algoritmos de planificación para la transmisión de datos en tiempo real con IEEE 802.15.4

    Directory of Open Access Journals (Sweden)

    Sixto Enrique Campaña Bastidas

    2015-10-01

    Full Text Available Las redes de sensores inalámbricas (WSN se están extendiendo a muchos campos de aplicación, tales como ciudades inteligentes, ambientes inteligentes, internet de las cosas, entre otras tecnologías. Para muchasde estas tendencias es esencial establecer métodos para la entrega de paquetes, sobre todo aquellos que presenten garantías de tiempo real. En este trabajo se presenta un estudio de los avances recientes publicadosen la literatura científica, considerando principalmente las técnicas de acceso al medio y la planificación de transmisión de datos con garantías de tiempo real en WSN basadas en el estándar IEEE 802.15.4. Este estudiopresenta las características más importantes, así como las principales diferencias entre las distintas técnicas. Al final se presentan algunas conclusiones y se proponen futuras líneas de investigación que buscan con interés la aplicación de WSN en ambientes con restricciones de tiempo real.

  9. Plasma expansion: fundamentals and applications

    International Nuclear Information System (INIS)

    Engeln, R; Mazouffre, S; Vankan, P; Bakker, I; Schram, D C

    2002-01-01

    The study of plasma expansion is interesting from a fundamental point of view as well as from a more applied point of view. We here give a short overview of the way properties like density, velocity and temperature behave in an expanding thermal plasma. Experimental data show that the basic phenomena of plasma expansion are to some extent similar to those of the expansion of a hot neutral gas. From the application point of view, we present first results on the use of an expanding thermal plasma in the plasma-activated catalysis of ammonia, from N 2 -H 2 mixtures

  10. pacientes con falla cardiaca

    Directory of Open Access Journals (Sweden)

    Diana Marcela Achury Saldaña

    2007-01-01

    Full Text Available Objetivo: determinar la adherencia al tratamiento de pacientes con falla cardiaca hospitalizados, al aplicar un plan educativo quefomenta el autocuidado.Método: estudio cuasiexperimental (entrevistas enfermera-paciente realizado entre diciembre de 2004 y mayo de 2006, con unamuestra de 50 pacientes seleccionados por conveniencia. Se diseñó un instrumento para evaluar los comportamientos de los pacientes,con base en algunos resultados de la adherencia y sus respectivos indicadores de la taxonomía NOC (Nursing out comes classification. Laadherencia al tratamiento fue medida en dos momentos: el primero durante la hospitalización, seguido de la aplicación del plan educativoantes del alta, que proporcionaba información en el manejo de su enfermedad desde una dimensión física, psicológica y social quepromueve el autocuidado; y el segundo un mes después del alta en su domicilio.Resultados: diferencias estadísticamente significativas (P=0,0001 que demuestran cómo mediante la capacitación al paciente enel manejo de su tratamiento farmacológico y no farmacológico, el establecimiento de una sana relación entre el profesional de enfermeríay el paciente, y la participación de la familia, se logra una total adherencia al tratamiento.Conclusiones: para lograr una adherencia total del paciente con falla cardiaca al tratamiento es necesario un proceso educativo y unseguimiento continuo y personalizado que motive permanentemente al paciente y se le reconozca el papel protagónico en su cuidado y manejo de la enfermedad.

  11. Warp drive with zero expansion

    Energy Technology Data Exchange (ETDEWEB)

    Natario, Jose [Department of Mathematics, Instituto Superior Tecnico (Portugal)

    2002-03-21

    It is commonly believed that Alcubierre's warp drive works by contracting space in front of the warp bubble and expanding the space behind it. We show that this contraction/expansion is but a marginal consequence of the choice made by Alcubierre and explicitly construct a similar spacetime where no contraction/expansion occurs. Global and optical properties of warp-drive spacetimes are also discussed.

  12. Expansion lyre-shaped tube

    International Nuclear Information System (INIS)

    Andro, Jean.

    1973-01-01

    The invention relates the expansion lyre-shaped tube portions formed in dudgeoned tubular bundles between two bottom plates. An expansion lyre comprises at least two sets of tubes of unequal lengths coplanar and symmetrical with respect to the main tube axis, with connecting portions between the tubes forming said sets. The invention applies to apparatus such as heat exchangers, heaters, superheaters or breeders [fr

  13. Estimates of expansion time scales

    International Nuclear Information System (INIS)

    Jones, E.M.

    1979-01-01

    Monte Carlo simulations of the expansion of a spacefaring civilization show that descendants of that civilization should be found near virtually every useful star in the Galaxy in a time much less than the current age of the Galaxy. Only extreme assumptions about local population growth rates, emigration rates, or ship ranges can slow or halt an expansion. The apparent absence of extraterrestrials from the solar system suggests that no such civilization has arisen in the Galaxy. 1 figure

  14. Strategic Complexity and Global Expansion

    DEFF Research Database (Denmark)

    Oladottir, Asta Dis; Hobdari, Bersant; Papanastassiou, Marina

    2012-01-01

    The purpose of this paper is to analyse the determinants of global expansion strategies of newcomer Multinational Corporations (MNCs) by focusing on Iceland, Israel and Ireland. We argue that newcomer MNCs from small open economies pursue complex global expansion strategies (CGES). We distinguish....... The empirical evidence suggests that newcomer MNCs move away from simplistic dualities in the formulation of their strategic choices towards more complex options as a means of maintaining and enhancing their global competitiveness....

  15. Range expansion of heterogeneous populations.

    Science.gov (United States)

    Reiter, Matthias; Rulands, Steffen; Frey, Erwin

    2014-04-11

    Risk spreading in bacterial populations is generally regarded as a strategy to maximize survival. Here, we study its role during range expansion of a genetically diverse population where growth and motility are two alternative traits. We find that during the initial expansion phase fast-growing cells do have a selective advantage. By contrast, asymptotically, generalists balancing motility and reproduction are evolutionarily most successful. These findings are rationalized by a set of coupled Fisher equations complemented by stochastic simulations.

  16. competencia con China

    Directory of Open Access Journals (Sweden)

    Elena de la Paz Hernández Águila

    2007-01-01

    Full Text Available El artículo ofrece un diagnóstico del desempeño de la industria mexicana del calzado desde la década de los ochenta hasta la actualidad. Analiza la problemática que ha enfrentado esta rama industrial a partir del proceso de apertura comercial y de la competencia en su mercado interno con productos provenientes de países asiáticos, particularmente China. Problematiza al respecto los retos y las perspectivas que a mediano plazo enfrentará este sector empresarial y sobre las posibilidades de competir en el mercado globalizado.

  17. Construir con Madera

    OpenAIRE

    Olabe-Velasco, F. (Fermín); Val-Hernández, Y. (Yolanda); Varela-de-la-Cruz, P. (Perla); Cabrero-Ballarín, J.M. (José Manuel)

    2010-01-01

    Guía divulgativa ‘Construir con madera’, elaborada por la Cátedra Madera de la Universidad de Navarra y el Gobierno de Navarra. La publicación pretende explicar de forma sencilla los beneficios y posibilidades de este material en la construcción, tanto en lo que respecta a su resistencia, comportamiento frente al fuego, durabilidad, capacidad de aislamiento, propiedades acústicas, estética, respeto al medio ambiente y sostenibilidad como fuente de energía. A modo de ejemplo, en la ...

  18. On genus expansion of superpolynomials

    Energy Technology Data Exchange (ETDEWEB)

    Mironov, Andrei, E-mail: mironov@itep.ru [Lebedev Physics Institute, Moscow 119991 (Russian Federation); ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Morozov, Alexei, E-mail: morozov@itep.ru [ITEP, Moscow 117218 (Russian Federation); National Research Nuclear University MEPhI, Moscow 115409 (Russian Federation); Sleptsov, Alexei, E-mail: sleptsov@itep.ru [ITEP, Moscow 117218 (Russian Federation); Laboratory of Quantum Topology, Chelyabinsk State University, Chelyabinsk 454001 (Russian Federation); KdVI, University of Amsterdam (Netherlands); Smirnov, Andrey, E-mail: asmirnov@math.columbia.edu [ITEP, Moscow 117218 (Russian Federation); Columbia University, Department of Mathematics, New York (United States)

    2014-12-15

    Recently it was shown that the (Ooguri–Vafa) generating function of HOMFLY polynomials is the Hurwitz partition function, i.e. that the dependence of the HOMFLY polynomials on representation R is naturally captured by symmetric group characters (cut-and-join eigenvalues). The genus expansion and expansion through Vassiliev invariants explicitly demonstrate this phenomenon. In the present paper we claim that the superpolynomials are not functions of such a type: symmetric group characters do not provide an adequate linear basis for their expansions. Deformation to superpolynomials is, however, straightforward in the multiplicative basis: the Casimir operators are β-deformed to Hamiltonians of the Calogero–Moser–Sutherland system. Applying this trick to the genus and Vassiliev expansions, we observe that the deformation is fully straightforward only for the thin knots. Beyond the family of thin knots additional algebraically independent terms appear in the Vassiliev and genus expansions. This can suggest that the superpolynomials do in fact contain more information about knots than the colored HOMFLY and Kauffman polynomials. However, even for the thin knots the beta-deformation is non-innocent: already in the simplest examples it seems inconsistent with the positivity of colored superpolynomials in non-(anti)symmetric representations, which also happens in I. Cherednik's (DAHA-based) approach to the torus knots.

  19. Entrevista con Giovanni Levi

    Directory of Open Access Journals (Sweden)

    Monica Oliveira

    2017-06-01

    Full Text Available En esta entrevista, Giovanni Levi - como un conocedor del tema de Familia - realiza una importante evaluación sobre el actual estado de las investigaciones realizadas en el Brasil y em el exterior. Con estilo franco, agudo y lucido critica las visiones tradicionales y sus ilusiones ypropone nuevos conceptos y métodos. La historia de la familia debería ceder espacio para el estudio de las redes relacionales o de los mundos relacionales. De la misma forma, la historia cuantitativa debería abrir espacio para el estudio de las cualidades. Ya con relación a la historia de las elites, tan estudiada y reproducida en una diversidad de trabajos, que deberíase mirar en otra perspectiva. Es decir, no mirar a las reglas sociales predeterminadas, sino a los desvíos y a las variaciones. Levi defiende que los historiadores deben trascender a los documentos que se encuentran fácilmente y que pueden fortalecer perspectivas deformadas y esequilibradas de la sociedad. Para él, los historiadores deben esforzarse por estudiar a aquellos grupos que dejaron pocos rastros documentales. En ese esfuerzo existiría una nueva mirada sobre la historia de la familia.

  20. Entrevista con Patricia Ariza

    Directory of Open Access Journals (Sweden)

    Esperanza Londoño La Rotta

    2017-01-01

    Full Text Available Pensamiento, Palabra y Obra entrevista a una artista, feminista y activista política, quien como mujer y artista ha permitido pensar el arte más allá de un simple espectáculo. Toda una vida dedicada al teatro y a darle voz, a través de sus obras, a víctimas del conflicto colombiano, defensora de derechos humanos; además de hacer evidente en su vida y a través de la plataforma “Artistas por la paz”, las múltiples relaciones que se pueden establecer entre el arte, la construcción de paz y la resolución de conflictos. Hablamos en su casa, en medio del calor de la bienvenida con Patricia Ariza, directora del festival alternativo de teatro, de Mujeres en Escena y de la Corporación Colombiana de Teatro, entre otras muchas actividades que voluntariamente su espíritu libertario ha asumido. Esta entrevista se realizó antes del 2 de octubre, pero con la revisión de los acuerdos que propició el plebiscito ganado por una ínfima minoría por el no, sigue siendo vigente este planteamiento.

  1. Low Thermal Expansion Glass Ceramics

    CERN Document Server

    Bach, Hans

    2005-01-01

    This book appears in the authoritative series reporting the international research and development activities conducted by the Schott group of companies. This series provides an overview of Schott's activities for scientists, engineers, and managers from all branches of industry worldwide in which glasses and glass ceramics are of interest. Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated. This new extended edition describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics. The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions. Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization. Thus g...

  2. Low thermal expansion glass ceramics

    CERN Document Server

    1995-01-01

    This book is one of a series reporting on international research and development activities conducted by the Schott group of companies With the series, Schott aims to provide an overview of its activities for scientists, engineers, and managers from all branches of industry worldwide where glasses and glass ceramics are of interest Each volume begins with a chapter providing a general idea of the current problems, results, and trends relating to the subjects treated This volume describes the fundamental principles, the manufacturing process, and applications of low thermal expansion glass ceramics The composition, structure, and stability of polycrystalline materials having a low thermal expansion are described, and it is shown how low thermal expansion glass ceramics can be manufactured from appropriately chosen glass compositions Examples illustrate the formation of this type of glass ceramic by utilizing normal production processes together with controlled crystallization Thus glass ceramics with thermal c...

  3. Regulation of gas infrastructure expansion

    International Nuclear Information System (INIS)

    De Joode, J.

    2012-01-01

    The topic of this dissertation is the regulation of gas infrastructure expansion in the European Union (EU). While the gas market has been liberalised, the gas infrastructure has largely remained in the regulated domain. However, not necessarily all gas infrastructure facilities - such as gas storage facilities, LNG import terminals and certain gas transmission pipelines - need to be regulated, as there may be scope for competition. In practice, the choice of regulation of gas infrastructure expansion varies among different types of gas infrastructure facilities and across EU Member States. Based on a review of economic literature and on a series of in-depth case studies, this study explains these differences in choices of regulation from differences in policy objectives, differences in local circumstances and differences in the intrinsic characteristics of the infrastructure projects. An important conclusion is that there is potential for a larger role for competition in gas infrastructure expansion.

  4. Aspectos relevantes en la rehabilitación de los niños con enfermedades neuromusculares

    Directory of Open Access Journals (Sweden)

    V. Rebeca Valdebenito, Dra.

    2014-03-01

    Full Text Available Las Enfermedades Neuromusculares representan un grupo heterogéneo de trastornos que incluyen alteraciones en la motoneurona, nervios periféricos, transmisión neuromuscular y las patologías que afectan al músculo propiamente tal. Su progresión varía considerablemente presentando diversos déficits que pueden variar desde la debilidad muscular, pérdida sensorial, dolor, fatiga y la disfunción autonómica, los que se combinan para dar lugar al daño músculo-esquelético generando limitaciones en las actividades de la vida diaria y restricciones en la participación. Es por esto, que en las últimas décadas se han creado programas de rehabilitación integrados por un equipo multidisciplinario, que trabajan de manera coordinada, abarcando todos los factores que producen y aumentan la discapacidad realizando el control, la prevención y el tratamiento de las complicaciones que derivan durante la evolución de este grupo de enfermedades, con el objetivo de lograr la mayor integración que el estadio de su enfermedad pueda permitir.

  5. The loop expansion as a divergent-power-series expansion

    International Nuclear Information System (INIS)

    Murai, N.

    1981-01-01

    The loop expansion should be divergent, possibly an asymptotic one, in the Euclidean path integral formulation. This consideration is important in applications of the symmetric and mass-independent renormalization. The [1,1] Pade approximant is calculated in a PHI 4 model. Its classical vacua may be not truely stable for nonzero coupling constant. (author)

  6. Cosmological expansion and local physics

    International Nuclear Information System (INIS)

    Faraoni, Valerio; Jacques, Audrey

    2007-01-01

    The interplay between cosmological expansion and local attraction in a gravitationally bound system is revisited in various regimes. First, weakly gravitating Newtonian systems are considered, followed by various exact solutions describing a relativistic central object embedded in a Friedmann universe. It is shown that the 'all or nothing' behavior recently discovered (i.e., weakly coupled systems are comoving while strongly coupled ones resist the cosmic expansion) is limited to the de Sitter background. New exact solutions are presented which describe black holes perfectly comoving with a generic Friedmann universe. The possibility of violating cosmic censorship for a black hole approaching the big rip is also discussed

  7. Temperature expansions for magnetic systems

    International Nuclear Information System (INIS)

    Cangemi, D.; Dunne, G.

    1996-01-01

    We derive finite temperature expansions for relativistic fermion systems in the presence of background magnetic fields, and with nonzero chemical potential. We use the imaginary-time formalism for the finite temperature effects, the proper-time method for the background field effects, and zeta function regularization for developing the expansions. We emphasize the essential difference between even and odd dimensions, focusing on 2+1 and 3+1 dimensions. We concentrate on the high temperature limit, but we also discuss the T=0 limit with nonzero chemical potential. Copyright copyright 1996 Academic Press, Inc

  8. Bearing-Mounting Concept Accommodates Thermal Expansion

    Science.gov (United States)

    Nespodzany, Robert; Davis, Toren S.

    1995-01-01

    Pins or splines allow radial expansion without slippage. Design concept for mounting rotary bearing accommodates differential thermal expansion between bearing and any structure(s) to which bearing connected. Prevents buildup of thermal stresses by allowing thermal expansion to occur freely but accommodating expansion in such way not to introduce looseness. Pin-in-slot configuration also maintains concentricity.

  9. Energy expansion planning by considering electrical and thermal expansion simultaneously

    International Nuclear Information System (INIS)

    Abbasi, Ali Reza; Seifi, Ali Reza

    2014-01-01

    Highlights: • This paper focused on the expansion planning optimization of energy systems. • Employing two form of energy: the expansion of electrical and thermal energies. • The main objective is to minimize the costs. • A new Modified Honey Bee Mating Optimization (MHBMO) algorithm is applied. - Abstract: This study focused on the expansion planning optimization of energy systems employing two forms of energy: the expansion of electrical and thermal energies simultaneously. The main objective of this investigation is confirming network adequacy by adding new equipment to the network, over a given planning horizon. The main objective of the energy expansion planning (EEP) is to minimize the real energy loss, voltage deviation and the total cost of installation equipments. Since the objectives are different and incommensurable, it is difficult to solve the problem by the conventional approaches that may optimize a single objective. So, the meta-heuristic algorithm is applied to this problem. Here, Honey Bee Mating Optimization algorithm (HBMO) as a new evolutionary optimization algorithm is utilized. In order to improve the total ability of HBMO for the global search and exploration, a new modification process is suggested such a way that the algorithm will search the total search space globally. Also, regarding the uncertainties of the new complicated energy systems, in this paper for the first time, the EEP problem is investigated in a stochastic environment by the use of probabilistic load flow technique based on Point Estimate Method (PEM). In order to evaluate the feasibility and effectiveness of the proposed algorithm, two modified test systems are used as case studies

  10. The Thermal Expansion Of Feldspars

    Science.gov (United States)

    Hovis, G. L.; Medford, A.; Conlon, M.

    2009-12-01

    Hovis and others (1) investigated the thermal expansion of natural and synthetic AlSi3 feldspars and demonstrated that the coefficient of thermal expansion (α) decreases significantly, and linearly, with increasing room-temperature volume (VRT). In all such feldspars, therefore, chemical expansion limits thermal expansion. The scope of this work now has been broadened to include plagioclase and Ba-K feldspar crystalline solutions. X-ray powder diffraction data have been collected between room temperature and 925 °C on six plagioclase specimens ranging in composition from anorthite to oligoclase. When combined with thermal expansion data for albite (2,3,4) a steep linear trend of α as a function of VRT emerges, reflecting how small changes in composition dramatically affect expansion behavior. The thermal expansion data for five synthetic Ba-K feldspars ranging in composition from 20 to 100 mole percent celsian, combined with data for pure K-feldspar (3,4), show α-VRT relationships similar in nature to the plagioclase series, but with a slope and intercept different from the latter. Taken as a group all Al2Si2 feldspars, including anorthite and celsian from the present study along with Sr- (5) and Pb-feldspar (6) from other workers, show very limited thermal expansion that, unlike AlSi3 feldspars, has little dependence on the divalent-ion (or M-) site occupant. This apparently is due to the necessitated alternation of Al and Si in the tetrahedral sites of these minerals (7), which in turn locks the tetrahedral framework and makes the M-site occupant nearly irrelevant to expansion behavior. Indeed, in feldspar series with coupled chemical substitution it is the change away from a 1:1 Al:Si ratio that gives feldspars greater freedom to expand. Overall, the relationships among α, chemical composition, and room-temperature volume provide useful predictive tools for estimating feldspar thermal expansion and give insight into the controls of expansion behavior in

  11. Crude oil pipeline expansion summary

    International Nuclear Information System (INIS)

    2005-02-01

    The Canadian Association of Petroleum Producers has been working with producers to address issues associated with the development of new pipeline capacity from western Canada. This document presents an assessment of the need for additional oil pipeline capacity given the changing mix of crude oil types and forecasted supply growth. It is of particular interest to crude oil producers and contributes to current available information for market participants. While detailed, the underlying analysis does not account for all the factors that may come into play when individual market participants make choices about which expansions they may support. The key focus is on the importance of timely expansion. It was emphasized that if pipeline expansions lags the crude supply growth, then the consequences would be both significant and unacceptable. Obstacles to timely expansion are also discussed. The report reviews the production and supply forecasts, the existing crude oil pipeline infrastructure, opportunities for new market development, requirements for new pipeline capacity and tolling options for pipeline development. tabs., figs., 1 appendix

  12. Model of clinker capacity expansion

    CSIR Research Space (South Africa)

    Stylianides, T

    1998-10-01

    Full Text Available This paper describes a model which has been applied in practice to determine an optimal plan for clinker capacity expansion. The problem was formulated as an integer linear program aiming to determine the optimal number, size and location of kilns...

  13. The bootstrap and edgeworth expansion

    CERN Document Server

    Hall, Peter

    1992-01-01

    This monograph addresses two quite different topics, in the belief that each can shed light on the other. Firstly, it lays the foundation for a particular view of the bootstrap. Secondly, it gives an account of Edgeworth expansion. Chapter 1 is about the bootstrap, witih almost no mention of Edgeworth expansion; Chapter 2 is about Edgeworth expansion, with scarcely a word about the bootstrap; and Chapters 3 and 4 bring these two themes together, using Edgeworth expansion to explore and develop the properites of the bootstrap. The book is aimed a a graduate level audience who has some exposure to the methods of theoretical statistics. However, technical details are delayed until the last chapter (entitled "Details of Mathematical Rogour"), and so a mathematically able reader without knowledge of the rigorous theory of probability will have no trouble understanding the first four-fifths of the book. The book simultaneously fills two gaps in the literature; it provides a very readable graduate level account of t...

  14. On Fourier re-expansions

    OpenAIRE

    Liflyand, E.

    2012-01-01

    We study an extension to Fourier transforms of the old problem on absolute convergence of the re-expansion in the sine (cosine) Fourier series of an absolutely convergent cosine (sine) Fourier series. The results are obtained by revealing certain relations between the Fourier transforms and their Hilbert transforms.

  15. On persistently positively expansive maps

    Directory of Open Access Journals (Sweden)

    Alexander Arbieto

    2010-06-01

    Full Text Available In this paper, we prove that any C¹-persistently positively expansive map is expanding. This improves a result due to Sakai (Sakai 2004.Neste artigo, mostramos que todo mapa C¹-persistentemente positivamente expansivo e expansor. Isto melhora um resultado devido a Sakai (Sakai 2004.

  16. preescolares desnutridos con madres con obesidad y sin obesidad

    Directory of Open Access Journals (Sweden)

    Viridiana Vanessa Conzuelo-González

    2009-01-01

    Full Text Available El primer objetivo fue conocer cuántos menores de cinco años con diferentes grados de desnutrición tienen una madre con sobrepeso/obesidad/ en una comunidad indígena que vive en extrema pobreza y bajo condiciones de migración masculina internacional. El segundo fue comparar tres variables socionutricionales (ingreso familiar, educación de la madre y adecuación nutrimental de la dieta diaria entre estos hogares y los hogares con desnutrición infantil y madres sin obesidad. Se realizó un estudio transversal (2006-2007, en la comunidad mazahua de San Francisco Tepeolulco, Municipio de Temascalcingo; que incluyó a 85 hogares integrados por preescolares con desnutrición inscritos al programa Oportunidades. Se determinó el estado nutrición de los preescolares con indicadores antropométricos y se obtuvo el IMC de las madres de estos infantes. Se aplicó una encuesta socionutricional, incluida el recordatorio de 24 horas, y complementado con la observación participante (cualitativa. Se encontró que 83% de las madres mazahuas presentaron sobrepeso u obesidad. El estado de nutrición de los preescolares con madres con obesidad presentó un porcentaje mayor de desnutrición (76%. En la variable género, se encontró que 54% de los niños con madres con obesidad tenía baja talla. Al relacionar el nivel educativo de la madre, esta variable resultó ser estadísticamente significativa (p=0.015, donde el analfabetismo está más relacionado con la desnutrición infantil que tienen madres de bajo y/o peso normal. La elevada prevalencia de hogares conformados con preescolares con desnutrición y madres con obesidad, es un síntoma más de la pobreza en zonas indígenas en México, con bajo índice de desarrollo humano.

  17. autorregulado con estudiantes universitarios

    Directory of Open Access Journals (Sweden)

    Jairo Andrés Montes

    2005-01-01

    Full Text Available El propósito del presente estudio es describir la forma en la que se presentan los procesos de aprendizaje autorregulado con un grupo de estudiantes (22 estudiantes de tercer semestre de Psicología de la PUJ, Cali, en el evento de preparación para la presentación un examen. Asimismo se describen las correlaciones que ocurren entre las distintas fases de dicho proceso de autorregulación del aprendizaje. Para conseguir los objetivos propuestos se ha hecho uso de una observación de desempeño en tiempo real, es decir, de la observación durante una sesión de preparación de examen de los estudiantes, en la cual se emplearon protocolos verbales para dar cuenta de lo que «pasaba por su mente» mientras estudiaban. Una entrevista semi-estructurada y una prueba objetiva. Los resultados fueron analizados a la luz del modelo mixto de procesamiento de información y constructivismo abordado por Winne(1998. Como resultado se encontró una relación significativa entre los niveles de desempeño en el proceso de ARR y el resultado del examen. Igualmente se encontraron bajos niveles de regulación en una parte importante de la muestra y un desfase significativo entre conocimiento declarativo de ARR y desempeño en el mismo

  18. Exponential Expansion in Evolutionary Economics

    DEFF Research Database (Denmark)

    Frederiksen, Peter; Jagtfelt, Tue

    2013-01-01

    This article attempts to solve current problems of conceptual fragmentation within the field of evolutionary economics. One of the problems, as noted by a number of observers, is that the field suffers from an assemblage of fragmented and scattered concepts (Boschma and Martin 2010). A solution...... to this problem is proposed in the form of a model of exponential expansion. The model outlines the overall structure and function of the economy as exponential expansion. The pictographic model describes four axiomatic concepts and their exponential nature. The interactive, directional, emerging and expanding...... concepts are described in detail. Taken together it provides the rudimentary aspects of an economic system within an analytical perspective. It is argued that the main dynamic processes of the evolutionary perspective can be reduced to these four concepts. The model and concepts are evaluated in the light...

  19. Production expansion continues to accelerate

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This paper reports that Saudi Arabian Oil Co. (Saudi Aramco) is continuing its accelerated Crude Oil Expansion Program initiated in 1989 that aims at achieving a 10 million bpd productive capacity by 1995. In addition to major engineering, construction and renovation work related to production expansion, Saudi Aramco drilling and workover operations have been markedly expanded. Since January 1991, rig activity has doubled. As an indication of aging of Saudi production, projects include modernizing current injection water treatment facilities, installing a new seawater injection plant on the Persian Gulf, installing dewatering facilities in a number of locations and installing a pilot gas lift project. In addition, equipment orders indicate the new discoveries south of Riyadh may also need the assistance of water injection from inception of production

  20. Shrub expansion in SW Greenland

    DEFF Research Database (Denmark)

    Jørgensen, Rasmus Halfdan

    Arctic regions have experienced higher temperatures in recent decades, and the warming trend is projected to continue in the coming years. Arctic ecosystems are considered to be particularly vulnerable to climate change. Expansion of shrubs has been observed widely in tundra areas across the Arctic......, and has a range of ecosystem effects where it occurs. Shrub expansion has to a large extend been attributed to increasing temperatures over the past century, while grazing and human disturbance have received less attention. Alnus viridis ssp. crispa is a common arctic species that contributes...... to increasing shrub cover. Despite this, there is only limited experimental evidence that growth of the species responds to warming. Plant populations in fragmented and isolated locations could face problems adapting to a warming climate due to limited genetic variation and restricted migration from southern...

  1. RELIABILITY OF LENTICULAR EXPANSION COMPENSATORS

    Directory of Open Access Journals (Sweden)

    Gabriel BURLACU,

    2011-11-01

    Full Text Available Axial lenticular compensators are made to take over the longitudinal heat expansion, shock , vibration and noise, made elastic connections for piping systems. In order to have a long life for installations it is necessary that all elements, including lenticular compensators, have a good reliability. This desire can be did by technology of manufactoring and assembly of compensators, the material for lenses and by maintenance.of compensator

  2. Puentes con vigas pretensadas

    Directory of Open Access Journals (Sweden)

    Editorial, Equipo

    1965-07-01

    Full Text Available This paper describes one of the three bridges which Hidrocivil, S. A., has built in Catalonia (northern Spain, over the river Ripoll. The other two bridges are very similar to this one, both in construction and design, and show only minor adjustments to the local topography. The contracting firm proposed several alterations in the prefabrication and constructional procedure, in relation to the initial project, and these changes were accepted. The main feature of these projects is the use of prestressed beams, built at the workshop in sections, and joined together by means of sixty 7 mm cables in each beam. As the shear forces are more acute at the joints, the end of each section has a kind of diaphragm, to provide a large contact area, and hence greater surface to transmit the shear forces. The methods of construction are also of interest. Briefly, they involve building the bridge piles, and use these to support a provisional structure with transversal movement. This provisional structure, in turn, served as platform for two bridge cranes, which lifted the girders to their final location. After the first span was completed, the deck was concreted and the auxiliary structure pushed forward to the next span, to repeat the same operations. This arrangement saved the use of provisional framework.En este trabajo se describe uno de los tres puentes que Hidrocivil, S. A., ha construido.—previo concurso— en la región catalana; concretamente, el que salva el río Ripoll. Los otros dos no han sido objeto de descripción general por ser muy similares, en lo que a ejecución y concepción se refiere, con la única variante que presentan las características topográficas locales. La empresa propuso ciertas variantes— que fueron aceptadas— en la prefabricación y métodos de construcción. El interés de estas obras se centra en el empleo de vigas pretensadas, prefabricadas en taller por trozos, y solidarizados en el mismo mediante las operaciones

  3. Violencia con el anciano

    Directory of Open Access Journals (Sweden)

    Rita Campillo Motilva

    2002-08-01

    Full Text Available La violencia doméstica es tan antigua como la humanidad misma y se reconocen la violencia infantil, contra la mujer y al anciano, fundamentalmente; siendo este último grupo una población en ascenso por las mayores expectativas de vida de los últimos años. Como resultado de ello, el número de casos de abuso en el anciano se incrementará y el impacto de este abuso sobre la salud debe ser considerado de forma adecuada. La gama de maltratos es variadísima e incluye el abuso físico, emocional, financiero, sexual, por negligencia, negación a brindarle ayuda y otras formas más. Los ancianos con deterioro cognitivo son los más vulnerables. El médico en la atención primaria de salud es un pilar importante en la prevención y educación de este problema.Domestic violence is as old as humanity itself. Child, women and elderly abuse are mainly recognized. The elderly group is increasing due to the higher life expectancy experimented during the last years. As a result, the number of battered elderly will grow and the impact of this abuse on health should be adequately considered. The range of abuse is very wide and it includes physical, emotional, financial and sexual abuse, negligence, rejection to give assistance and others. The elderly with cognitive deterioration are the most vulnerable. The physician at the primary health care level is an important milestone in the prevention and education of this problem.

  4. A Power Series Expansion and Its Applications

    Science.gov (United States)

    Chen, Hongwei

    2006-01-01

    Using the power series solution of a differential equation and the computation of a parametric integral, two elementary proofs are given for the power series expansion of (arcsin x)[squared], as well as some applications of this expansion.

  5. Desarrollo de un modelo generalizado para realimentación de fuerza y torque en cirugía cardiotorácica robótica mínimamente invasiva: determinación de condiciones y restricciones

    Directory of Open Access Journals (Sweden)

    Vera Pérez, IEE., PhD.(c

    2011-07-01

    Conclusiones: Las condiciones relacionadas con la incorporación de un sensor de fuerza y la percepción del cirujano en cuanto al tacto y la fuerza aplicada, resultan ser importantes en procedimientos de MICS robótica y requiere la inclusión de un sistema de control que permita la optimización de procedimientos por telepresencia.

  6. Strain expansion-reduction approach

    Science.gov (United States)

    Baqersad, Javad; Bharadwaj, Kedar

    2018-02-01

    Validating numerical models are one of the main aspects of engineering design. However, correlating million degrees of freedom of numerical models to the few degrees of freedom of test models is challenging. Reduction/expansion approaches have been traditionally used to match these degrees of freedom. However, the conventional reduction/expansion approaches are only limited to displacement, velocity or acceleration data. While in many cases only strain data are accessible (e.g. when a structure is monitored using strain-gages), the conventional approaches are not capable of expanding strain data. To bridge this gap, the current paper outlines a reduction/expansion technique to reduce/expand strain data. In the proposed approach, strain mode shapes of a structure are extracted using the finite element method or the digital image correlation technique. The strain mode shapes are used to generate a transformation matrix that can expand the limited set of measurement data. The proposed approach can be used to correlate experimental and analytical strain data. Furthermore, the proposed technique can be used to expand real-time operating data for structural health monitoring (SHM). In order to verify the accuracy of the approach, the proposed technique was used to expand the limited set of real-time operating data in a numerical model of a cantilever beam subjected to various types of excitations. The proposed technique was also applied to expand real-time operating data measured using a few strain gages mounted to an aluminum beam. It was shown that the proposed approach can effectively expand the strain data at limited locations to accurately predict the strain at locations where no sensors were placed.

  7. Expansion of protein domain repeats.

    Directory of Open Access Journals (Sweden)

    Asa K Björklund

    2006-08-01

    Full Text Available Many proteins, especially in eukaryotes, contain tandem repeats of several domains from the same family. These repeats have a variety of binding properties and are involved in protein-protein interactions as well as binding to other ligands such as DNA and RNA. The rapid expansion of protein domain repeats is assumed to have evolved through internal tandem duplications. However, the exact mechanisms behind these tandem duplications are not well-understood. Here, we have studied the evolution, function, protein structure, gene structure, and phylogenetic distribution of domain repeats. For this purpose we have assigned Pfam-A domain families to 24 proteomes with more sensitive domain assignments in the repeat regions. These assignments confirmed previous findings that eukaryotes, and in particular vertebrates, contain a much higher fraction of proteins with repeats compared with prokaryotes. The internal sequence similarity in each protein revealed that the domain repeats are often expanded through duplications of several domains at a time, while the duplication of one domain is less common. Many of the repeats appear to have been duplicated in the middle of the repeat region. This is in strong contrast to the evolution of other proteins that mainly works through additions of single domains at either terminus. Further, we found that some domain families show distinct duplication patterns, e.g., nebulin domains have mainly been expanded with a unit of seven domains at a time, while duplications of other domain families involve varying numbers of domains. Finally, no common mechanism for the expansion of all repeats could be detected. We found that the duplication patterns show no dependence on the size of the domains. Further, repeat expansion in some families can possibly be explained by shuffling of exons. However, exon shuffling could not have created all repeats.

  8. Nuclear fuel reprocessing expansion strategies

    International Nuclear Information System (INIS)

    Gallagher, J.M.

    1975-01-01

    A description is given of an effort to apply the techniques of operations research and energy system modeling to the problem of determination of cost-effective strategies for capacity expansion of the domestic nuclear fuel reprocessing industry for the 1975 to 2000 time period. The research also determines cost disadvantages associated with alternative strategies that may be attractive for political, social, or ecological reasons. The sensitivity of results to changes in cost assumptions was investigated at some length. Reactor fuel types covered by the analysis include the Light Water Reactor (LWR), High-Temperature Gas-Cooled Reactor (HTGR), and the Fast Breeder Reactor (FBR)

  9. Thermal expansion of LATGS crystals

    International Nuclear Information System (INIS)

    Kassem, M.E.; Kandil, S.H.; Hamed, A.E.; Stankowska, J.

    1989-04-01

    The thermal expansion of triglycine sulphate crystals doped with L-α alanine (LATGS) has been studied around the phase transition temperature (30-60 deg. C) using thermomechanical analysis TMA. With increasing the content of admixture, the transition temperature (T c ) was shifted towards higher values, while the relative changes in the dimension of the crystals (ΔL/L 0 ) of the studied directions varied both in the para- and ferroelectric phases. The transition width in the case of doped crystals was found to be broad, and this broadening increases with increasing the content of L-α alanine. (author). 12 refs, 3 figs

  10. Contribution of thermal expansion and

    Directory of Open Access Journals (Sweden)

    O.I.Pursky

    2007-01-01

    Full Text Available A theoretical model is developed to describe the experimental results obtained for the isobaric thermal conductivity of rare gas solids (RGS. The isobaric thermal conductivity of RGS has been analysed within Debye approximation with regard to the effect of thermal expansion. The suggested model takes into consideration the fact that thermal conductivity is determined by U-processes while above the phonon mobility edge it is determined by "diffusive" modes migrating randomly from site to site. The mobility edge ω0 is determined from the condition that the phonon mean-free path restricted by the U-processes cannot be smaller than half of the phonon wavelength.

  11. High thermal expansion, sealing glass

    Science.gov (United States)

    Brow, R.K.; Kovacic, L.

    1993-11-16

    A glass composition is described for hermetically sealing to high thermal expansion materials such as aluminum alloys, stainless steels, copper, and copper/beryllium alloys, which includes between about 10 and about 25 mole percent Na[sub 2]O, between about 10 and about 25 mole percent K[sub 2]O, between about 5 and about 15 mole percent Al[sub 2]O[sub 3], between about 35 and about 50 mole percent P[sub 2]O[sub 5] and between about 5 and about 15 mole percent of one of PbO, BaO, and mixtures thereof. The composition, which may also include between 0 and about 5 mole percent Fe[sub 2]O[sub 3] and between 0 and about 10 mole percent B[sub 2]O[sub 3], has a thermal expansion coefficient in a range of between about 160 and 210[times]10[sup [minus]7]/C and a dissolution rate in a range of between about 2[times]10[sup [minus]7] and 2[times]10[sup [minus]9]g/cm[sup 2]-min. This composition is suitable to hermetically seal to metallic electrical components which will be subjected to humid environments over an extended period of time.

  12. Nonperturbative path integral expansion II

    International Nuclear Information System (INIS)

    Kaiser, H.J.

    1976-05-01

    The Feynman path integral representation of the 2-point function for a self-interacting Bose field is investigated using an expansion ('Path Integral Expansion', PIE) of the exponential of the kinetic term of the Lagrangian. This leads to a series - illustrated by a graph scheme - involving successively a coupling of more and more points of the lattice space commonly employed in the evaluation of path integrals. The values of the individual PIE graphs depend of course on the lattice constant. Two methods - Pade approximation and Borel-type extrapolation - are proposed to extract information about the continuum limit from a finite-order PIE. A more flexible PIE is possible by expanding besides the kinetic term a suitably chosen part of the interaction term too. In particular, if the co-expanded part is a mass term the calculation becomes only slightly more complicated than in the original formulation and the appearance of the graph scheme is unchanged. A significant reduction of the number of graphs and an improvement of the convergence of the PIE can be achieved by performing certain sums over an infinity of graph elements. (author)

  13. Acne polimorfo: tratamiento con Implacen

    Directory of Open Access Journals (Sweden)

    Rubén Pérez Armas

    1995-06-01

    Full Text Available Se realiza el estudio de 40 pacientes con acné polimorfo, los que fueron atendidos en la Consulta de Dermatología del Hospital Provincial Clinicoquirúrgico Docente "Celia Sánchez Manduley", en el período comprendido de enero de 1988 a diciembre de 1989. Se revisa la literatura médica sobre los diversos métodos y medicamentos utilizados en la terapéutica de esta dermatosis. Se describe el esquema de tratamiento empleado con implacén en 30 pacientes; los 10 restantes se trataron con placebo; se compara dicho esquema con los tradicionales y se observan mejores resultados con nuestro estudio. Se destaca la ausencia de recaídas, así como el resultado del tratamiento de acuerdo con el sexo.A study was performed in 40 patients presenting with polymorphic acne who were attended in the Dermatology Department of "Celia Sánchez Manduley" Clinicosurgical and Teaching Hospital from January, 1988 to December, 1989. A review of the literature was made seeking for the different methods and drugs used for the treatment of this dermatosis. The treatment schedule with the use of implacen in 30 patients is described. Such therapeutic schedule was compared with traditional ones and better results were observed with the use of implacen. The fact that there were no relapses is highlighted, as well as the result of treatment according to sex.

  14. Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

    OpenAIRE

    Fei-Ran Shen; Hao Kuang; Feng-Xia Hu; Hui Wu; Qing-Zhen Huang; Fei-Xiang Liang; Kai-Ming Qiao; Jia Li; Jing Wang; Yao Liu; Lei Zhang; Min He; Ying Zhang; Wen-Liang Zuo; Ji-Rong Sun

    2017-01-01

    Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn–Co–Ge–In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE o...

  15. Una metodología, con niveles de jerarquía, propuesta para el diseño de la distribución en plantas industriales

    Directory of Open Access Journals (Sweden)

    R.L. Romero

    2008-06-01

    Full Text Available El ingeniero que participa en la definición de la distribución en una planta piensa principalmente en aspectos de seguridad y económicos. En este trabajo se desarrolla un marco conceptual para descomponer y resolver los pasos de la distribución. El primer paso en un primer nivel de descomposición, se relaciona con los códigos, leyes y normas que regulan la construcción, porque son obligatorias en aspectos básicos y requerimientos de medio ambiente, seguridad y salud de los operarios. Seguidamente se refiere al tipo de construcción industrial, que define el conjunto. El segundo nivel, plantea el diseño de la planta de procesos, dónde las consideraciones de diseño actúan como restricciones a la función objetivo, representada por el costo total anual de operación, que debe minimizarse. Subsecuentemente, se vuelve a iterar para minimizar las distancias entre los sectores de planta involucrados. El procedimiento resultó adecuado para todo tipo de plantas industriales.

  16. con mala calidad de vida

    Directory of Open Access Journals (Sweden)

    Agustín Martín-Rodríguez

    2007-01-01

    Full Text Available En este estudio ex post facto se ha analizado si los familiares de pacientes con mala calidad de vida presentan diferencias en las variables clínicas de personalidad y relaciones familiares en función de que el paciente haya estado o no ingresado en una Unidad de Cuidados Intensivos. Seleccionamos dos grupos: 29 familiares de pacientes traumatizados graves transcurridos cuatro años de su ingreso en una UCI de Traumatología y con mala calidad de vida (debido a secuelas físicas y/o psicológicas tras el ingreso, tales como traumatismos craneoencefálicos, politraumatismos y tetraplejias traumáticas y 32 familiares de pacientes con mala calidad de vida con cuatro años de evolución de su enfermedad física (hipertensión, diabetes, artritis reumatoide y síndrome de intestino irritable que no han estado ingresados en la UCI. Para alcanzar nuestro objetivo empleamos una Encuesta Psicosocial y los siguientes instrumentos: Cuestionario de Análisis Clínico, Escala de Clima Social en la Familia y Escala de Adaptación Psicosocial de la Enfermedad. Los resultados mostraron que los familiares de pacientes con mala calidad de vida que estuvieron ingresados en la UCI hace cuatro años, presentan diferencias significativas en las variables agitación y expresividad comparados con los familiares de pacientes con mala calidad de vida que no han estado ingresados en la UCI.

  17. Expansion of passive safety function

    International Nuclear Information System (INIS)

    Inai, Nobuhiko; Nei, Hiromichi; Kumada, Toshiaki.

    1995-01-01

    Expansion of the use of passive safety functions is proposed. Two notions are presented. One is that, in the design of passive safety nuclear reactors where aversion of active components is stressed, some active components are purposely introduced, by which a system is built in such a way that it behaves in an apparently passive manner. The second notion is that, instead of using a passive safety function alone, a passive safety function is combined with some active components, relating the passivity in the safety function with enhanced controllability in normal operation. The nondormant system which the authors propose is one example of the first notion. This is a system in which a standby safety system is a portion of the normal operation system. An interpretation of the nondormant system via synergetics is made. As an example of the second notion, a PIUS density lock aided with active components is proposed and is discussed

  18. On the Equisummability of Hermite and Fourier Expansions

    Indian Academy of Sciences (India)

    We prove an equisummability result for the Fourier expansions and Hermite expansions as well as special Hermite expansions. We also prove the uniform boundedness of the Bochner-Riesz means associated to the Hermite expansions for polyradial functions.

  19. [Tissular expansion in giant congenital nevi treatment].

    Science.gov (United States)

    Nguyen Van Nuoi, V; Francois-Fiquet, C; Diner, P; Sergent, B; Zazurca, F; Franchi, G; Buis, J; Vazquez, M-P; Picard, A; Kadlub, N

    2014-08-01

    Surgical management of giant melanotic naevi remains a surgical challenge. Tissue expansion provides tissue of the same quality for the repair of defects. The aim of this study is to review tissular expansion for giant melanotic naevi. We conducted a retrospective study from 2000 to 2012. All children patients who underwent a tissular expansion for giant congenital naevi had been included. Epidemiological data, surgical procedure, complication rate and results had been analysed. Thirty-tree patients had been included; they underwent 61 procedures with 79 tissular-expansion prosthesis. Previous surgery, mostly simple excision had been performed before tissular expansion. Complete naevus excision had been performed in 63.3% of the cases. Complications occurred in 45% of the cases, however in 50% of them were minor. Iterative surgery increased the complication rate. Tissular expansion is a valuable option for giant congenital naevus. However, complication rate remained high, especially when iterative surgery is needed. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

  20. Simulation program for multiple expansion Stirling machines

    International Nuclear Information System (INIS)

    Walker, G.; Weiss, M.; Fauvel, R.; Reader, G.; Bingham, E.R.

    1992-01-01

    Multiple expansion Stirling machines have been a topic of interest at the University of Calgary for some years. Recently a second-order computer simulation program with integral graphics package for Stirling cryocoolers with up to four stages of expansion were developed and made available to the Stirling community. Adaptation of the program to multiple expansion Stirling power systems is anticipated. This paper briefly introduces the program and presents a specimen result

  1. Semiclassical expansions for confined N fermion systems

    International Nuclear Information System (INIS)

    Krivine, H.; Martorell, J.; Casas, M.

    1989-01-01

    A new derivation of the Wigner Kirkwood expansion for N-fermion systems is presented, showing explicitly the connection to the WKB approximation for a single level. This allows to study separately the two ansatz required to obtain the semiclassical expansions: the asymptotic expansions in powers of ℎ and the smoothing of quantal effects. We discuss the one dimensional and three dimensional, with spherical symmetry, cases. Applications for standard potentials used in nuclear physics are described in detail

  2. Thermal and hygroscopic expansion characteristics of bamboo

    OpenAIRE

    Huang, Puxi; Chang, Wen-shao; Ansell, Martin P.; Bowen, Chris R.; Chew, John Y. M.; Adamak, Vana i

    2017-01-01

    The expansion and contraction of bamboo caused by temperature and moisture variations must be evaluated\\ud if bamboo is to be utilised as a building material. However, detailed expansion data, especially data in the ascent and\\ud descent processes of temperature and moisture are unexplored. The aim of this study is to investigate the expansion\\ud characteristics of Phyllostachys edulis (Moso bamboo) in ascent and descent processes of temperature and moisture.\\ud The measurement of linear ther...

  3. $\\delta$-Expansion at Finite Temperature

    OpenAIRE

    Ramos, Rudnei O.

    1996-01-01

    We apply the $\\delta$-expansion perturbation scheme to the $\\lambda \\phi^{4}$ self-interacting scalar field theory in 3+1 D at finite temperature. In the $\\delta$-expansion the interaction term is written as $\\lambda (\\phi^{2})^{ 1 + \\delta}$ and $\\delta$ is considered as the perturbation parameter. We compute within this perturbative approach the renormalized mass at finite temperature at a finite order in $\\delta$. The results are compared with the usual loop-expansion at finite temperature.

  4. Chromatic Derivatives, Chromatic Expansions and Associated Spaces

    OpenAIRE

    Ignjatovic, Aleksandar

    2009-01-01

    This paper presents the basic properties of chromatic derivatives and chromatic expansions and provides an appropriate motivation for introducing these notions. Chromatic derivatives are special, numerically robust linear differential operators which correspond to certain families of orthogonal polynomials. Chromatic expansions are series of the corresponding special functions, which possess the best features of both the Taylor and the Shannon expansions. This makes chromatic derivatives and ...

  5. Thermal expansion in small metallic particles

    International Nuclear Information System (INIS)

    Ivanov, A.S.

    1985-01-01

    An anomalously low thermal expansion observable in small particles is attributed to extending effect of the shell. It is shown that the coefficient of thermal expansion of the oxide-film-coated aluminium particles calculated using elastic constants and coefficients of thermal expansion of massive materials agres well with those measured experimentally. The linear dilatation of the shell, its stress to rupture and the values of the structural tension are estimated vs the temperature

  6. Disjoint sum expansion method in FTA

    International Nuclear Information System (INIS)

    Ruan Keqiang

    1987-01-01

    An expansion formula for transforming boolean algebraic expressions into disjoint form was proved. Based on this expansion formula, a method for transforming system failure function into disjoint form was devised. The fact that the expansion can be done for several elements simulatneously makes the method flexible and fast. Some examples from fault tree analysis (FTA) and network analysis were examined by the new method to show its algorithm and its merit. Besides, by means of the proved expansion formula some boolean algebraic relations can proved very easily

  7. Thermal expansion of L-ascorbic acid

    Science.gov (United States)

    Nicolaï, B.; Barrio, M.; Tamarit, J.-Ll.; Céolin, R.; Rietveld, I. B.

    2017-04-01

    The specific volume of vitamin C has been investigated by X-ray powder diffraction as a function of temperature from 110 K up to complete degradation around 440 K. Its thermal expansion is relatively small in comparison with other organic compounds with an expansivity α v of 1.2(3) × 10-4 K-1. The structure consists of strongly bound molecules in the ac plane through a dense network of hydrogen bonds. The thermal expansion is anisotropic. Along the b axis, the expansion has most leeway and is about 10 times larger than in the other directions.

  8. Adiabatic supernova expansion into the circumstellar medium

    International Nuclear Information System (INIS)

    Band, D.L.; Liang, E.P.

    1987-01-01

    We perform one dimensional numerical simulations with a Lagrangian hydrodynamics code of the adiabatic expansion of a supernova into the surrounding medium. The early expansion follows Chevalier's analytic self-similar solution until the reverse shock reaches the ejecta core. We follow the expansion as it evolves towards the adiabatic blast wave phase. Some memory of the earlier phases of expansion is retained in the interior even when the outer regions expand as a blast wave. We find the results are sensitive to the initial configuration of the ejecta and to the placement of gridpoints. 6 refs., 2 figs

  9. Tratamiento con implantes Leader-Nano en paciente con oligodoncia

    Directory of Open Access Journals (Sweden)

    Salvador Javier Santos Medina

    2015-03-01

    Full Text Available Los implantes dentales de titanio han revolucionado el mundo de la rehabilitación desde su surgimiento. De manera particular, el empleo de implantes de carga inmediata acorta el tiempo quirúrgico y protésico, con el consiguiente bienestar estético. Se presenta el caso de una paciente femenina de 32 años de edad, con antecedentes de oligodoncia de ambos incisivos laterales superiores y portadora de prótesis parcial acrílica. Fue atendida por el equipo multidisciplinario de implantes en la Clínica Estomatológica Docente “3 de Octubre” y se le realizó tratamiento de rehabilitación integral con implantes Leader-Nano y prótesis fija con corona acrílica sobre dichos implantes. La implantología fue satisfactoria en la paciente; la mejoría estética y funcional, así como la satisfacción de la paciente, fueron los principales logros obtenidos

  10. con dietas suplementadas con Cromo-L-metionina

    Directory of Open Access Journals (Sweden)

    Ram\\u00F3n Garc\\u00EDa-Castillo

    2006-01-01

    Full Text Available Un total de 48 cerdos (Sus scrofa domesticus; 24 machos castrados y 24 hembras cruzados (Yorkshire, Hampshire, Duroc y Landrace de 3,5 a 4,0 meses de edad y 60,0 ± 5,0 kg PV en finalización. Se alimentaron con dietas isoproteícas (14,5 % PC e isoenergéticas (3.400 kcal EM/kg de MS, adicionadas con Cr-L-metionina (MiCroPlex® (0, 200, 400 y 600 ppb. El experimento tuvo una duración de 45 días y se realizó de agosto a noviembre del 2002 en las instalaciones de la Universidad Autónoma Agraria Antonio Narro, localizada en Saltillo, Coahuila, México. Al tener los animales aproximadamente 95 kg PV, se tomó muestra de 15 ml de sangre por cada animal para determinar la concentración de glucosa, ácido úrico, creatinina, urea, proteinas totales y colesterol. Se aplicó un diseño completamente al azar con arreglo factorial 2 x 4; dos para el factor sexo y cuatro para nivel de cromo. Los metabolitos en suero no fueron afectados (P>0,05 por el factor sexo. La glucosa en suero disminuyó (P<0,05 y el colesterol incrementó (P<0,05 con cromo en la dieta. Se concluye que el Cr incrementa el metabolismo de glucosa y disminuye el de colesterol, con lo cual puede haber energía disponible para síntesis de proteína la cual es necesaria para el crecimiento de los animales

  11. Hubble expansion in static spacetime

    International Nuclear Information System (INIS)

    Rossler, Otto E.; Froehlich, Dieter; Movassagh, Ramis; Moore, Anthony

    2007-01-01

    A recently proposed mechanism for light-path expansion in a static spacetime is based on the moving-lenses paradigm. Since the latter is valid independently of whether space expands or not, a static universe can be used to better see the implications. The moving-lenses paradigm is related to the paradigm of dynamical friction. If this is correct, a Hubble-like law is implicit. It is described quantitatively. A bent in the Hubble-like line is predictably implied. The main underlying assumption is Price's Principle (PI 3 ). If the theory is sound, the greatest remaining problem in cosmology becomes the origin of hydrogen. Since Blandford's jet production mechanism for quasars is too weak, a generalized Hawking radiation hidden in the walls of cosmic voids is invoked. A second prediction is empirical: slow pattern changes in the cosmic microwave background. A third is ultra-high redshifts for Giacconi quasars. Bruno's eternal universe in the spirit of Augustine becomes a bit less outlandish

  12. Primordial vorticity and gradient expansion

    CERN Document Server

    Giovannini, Massimo

    2012-01-01

    The evolution equations of the vorticities of the electrons, ions and photons in a pre-decoupling plasma are derived, in a fully inhomogeneous geometry, by combining the general relativistic gradient expansion and the drift approximation within the Adler-Misner-Deser decomposition. The vorticity transfer between the different species is discussed in this novel framework and a set of general conservation laws, connecting the vorticities of the three-component plasma with the magnetic field intensity, is derived. After demonstrating that a source of large-scale vorticity resides in the spatial gradients of the geometry and of the electromagnetic sources, the total vorticity is estimated to lowest order in the spatial gradients and by enforcing the validity of the momentum constraint. By acknowledging the current bounds on the tensor to scalar ratio in the (minimal) tensor extension of the $\\Lambda$CDM paradigm the maximal comoving magnetic field induced by the total vorticity turns out to be, at most, of the or...

  13. Organizadores e cortadores de comprimidos: riscos e restrições ao uso Organizadores y cortadores de comprimidos: riesgos y restricciones del uso Pill organizers and pill cutters: risks and limitations

    Directory of Open Access Journals (Sweden)

    Caroline Ribeiro de Borja-Oliveira

    2013-02-01

    Full Text Available Com base em análise documental, foram discutidas e problematizadas as limitações associadas à utilização de organizadores e cortadores de comprimidos, como questão de saúde pública. Os organizadores destinados ao armazenamento e transporte de comprimidos e cápsulas expõem essas formas farmacêuticas a fatores ambientais dos quais estariam protegidos em suas embalagens originais, comprometendo sua estabilidade, eficácia e segurança. Os cortadores oferecem risco adicional quanto a perda da eficácia, reações adversas e intoxicação. Por outro lado, o transporte de medicamentos pelo usuário é reflexo da conciliação entre autonomia e autocuidado e a partição de comprimidos é necessária para cumprir certos regimes posológicos. Conclui-se que cabe aos profissionais observar e orientar pacientes e cuidadores, visando à adequação dessas condutas e à prevenção dos riscos envolvidos.Objetivo Con base en análisis documental, se discutieron y señalaron los problemas de las limitaciones asociadas a la utilización de organizadores y cortadores de comprimidos, con respecto a la salud pública. Los organizadores destinados al almacenamiento y transporte de comprimidos y cápsulas exponen las formas farmacéuticas a factores ambientales de los cuales estarían protegidos en sus embalajes originales, comprometiendo su estabilidad, eficacia y seguridad. Los cortadores ofrecen riesgo adicional con relación a la pérdida de la eficacia, reacciones adversas e intoxicación. Por otro lado, el transporte de medicamentos por el usuario es reflejo de la conciliación entre autonomía y autocuidado, y la partición de comprimidos es necesaria para cumplir ciertos regímenes posológicos. Se concluye que resta a los profesionales observar y orientar pacientes y cuidadores, buscando la adecuación de esas conductas y la prevención de los riesgos involucrados.In this essay, based on documental analysis, the limitations associated with the

  14. Recubrimiento de acero con polidopamina

    OpenAIRE

    Carrasco Rodríguez, Javier

    2013-01-01

    Se ha obtenido recubrimientos de polidopamina en acero mecánicamente resistentes y con tiempos de obtención relativamente pequeños a través de la polimerización de la dopamina bajo diferentes condiciones.

  15. Negative thermal expansion materials: technological key for control of thermal expansion

    OpenAIRE

    Koshi Takenaka

    2012-01-01

    Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining pra...

  16. Finnish Higher Education Expansion and Regional Policy

    Science.gov (United States)

    Saarivirta, Toni

    2010-01-01

    This paper concentrates on the expansion of Finnish higher education between the 1960s and 1970s, exposes its background in the light of the policy decisions that were made, compares the unique features of this expansion with those of certain other countries, discusses the impact of the controlled "top down" governance of higher…

  17. The δ expansion for stochastic quantization

    International Nuclear Information System (INIS)

    Bender, C.M.; Cooper, F.; Milton, K.A.; Department of Physics, Brown University, Providence, Rhode Island 02912; Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexic o 87545; Department of Physics, The Ohio State University, Columbus, Ohio 43210; Department of Physics and Astronomy, University of Oklahoma, Norman, Oklaho ma 73019)

    1989-01-01

    Using a recently proposed perturbation expansion called the δ expansion, we show how to solve the Langevin equation associated with a gphi 4 field theory. We illustrate the technique in zero- and one-dimensional space-time, and then generalize this approach to d dimensions

  18. The heavy quark expansion of QCD

    International Nuclear Information System (INIS)

    Falk, A.F.

    1997-01-01

    These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs

  19. The heavy quark expansion of QCD

    Energy Technology Data Exchange (ETDEWEB)

    Falk, A.F. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Physics and Astronomy

    1997-06-01

    These lectures contain an elementary introduction to heavy quark symmetry and the heavy quark expansion. Applications such as the expansion of heavy meson decay constants and the treatment of inclusive and exclusive semileptonic B decays are included. Heavy hadron production via nonperturbative fragmentation processes is also discussed. 54 refs., 7 figs.

  20. Thermal expansion of doped lanthanum gallates

    Indian Academy of Sciences (India)

    Administrator

    Since the components are in intimate mechanical contact, any stress generated due to their thermal expansion mis- match during thermal cycling could lead to catastrophic failure of the cell. The functional materials must have similar thermal expansions to avoid mechanical stresses. Hence it is useful to study the thermal ...

  1. Platform Expansion Design as Strategic Choice

    DEFF Research Database (Denmark)

    Staykova, Kalina S.; Damsgaard, Jan

    2016-01-01

    In this paper, we address how the strategic choice of platform expansion design impacts the subse-quent platform strategy. We identify two distinct approaches to platform expansion – platform bun-dling and platform constellations, which currently co-exist. The purpose of this paper is to outline...

  2. Series expansion of the modified Einstein Procedure

    Science.gov (United States)

    Seema Chandrakant Shah-Fairbank

    2009-01-01

    This study examines calculating total sediment discharge based on the Modified Einstein Procedure (MEP). A new procedure based on the Series Expansion of the Modified Einstein Procedure (SEMEP) has been developed. This procedure contains four main modifications to MEP. First, SEMEP solves the Einstein integrals quickly and accurately based on a series expansion. Next,...

  3. Maxwell superalgebras and Abelian semigroup expansion

    Directory of Open Access Journals (Sweden)

    P.K. Concha

    2014-09-01

    Full Text Available The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2 leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM(N recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N. Moreover, we show that new minimal Maxwell superalgebras type sMm+2 and their N-extended generalization can be obtained using the S-expansion procedure.

  4. Use of expansion joints in power stations

    International Nuclear Information System (INIS)

    Birker; Rommerswinkel.

    1976-01-01

    The paper discusses the mode of action of different systems of expansion joints. Special regard is given to the problems of expansion of pipelines of high rated diameter as employed in today's large power plant turbines. Due to the limited space available, the important role of the spring rate of the bellows for the reaction forces and moments acting on the connection points is pointed out. Apart from this details are given on the fabrication and materials selection of expansion joint bellows, and problems are discussed which arise in connection with the mechanical or hydraulic deformation of bellows with one or more walls. The non-destructive methods now in use for the testing of expansion pipe joints are mentioned along with experiments to test their behaviour under changing loads. The paper concludes on some remarks concerning proper transport, storage and installation of expansion pipe joints. (orig./AK) [de

  5. Maxwell superalgebras and Abelian semigroup expansion

    Energy Technology Data Exchange (ETDEWEB)

    Concha, P.K.; Rodríguez, E.K. [Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Dipartimento di Scienza Applicata e Tecnologia (DISAT), Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Istituto Nazionale di Fisica Nucleare (INFN), Sezione di Torino, Via Pietro Giuria, 1, 10125 Torino (Italy)

    2014-09-15

    The Abelian semigroup expansion is a powerful and simple method to derive new Lie algebras from a given one. Recently it was shown that the S-expansion of so(3,2) leads us to the Maxwell algebra M. In this paper we extend this result to superalgebras, by proving that different choices of abelian semigroups S lead to interesting D=4 Maxwell Superalgebras. In particular, the minimal Maxwell superalgebra sM and the N-extended Maxwell superalgebra sM{sup (N)} recently found by the Maurer–Cartan expansion procedure, are derived alternatively as an S-expansion of osp(4|N). Moreover, we show that new minimal Maxwell superalgebras type sM{sub m+2} and their N-extended generalization can be obtained using the S-expansion procedure.

  6. Santiago, una ciudad con temor

    Directory of Open Access Journals (Sweden)

    Enrique Oviedo S.

    1999-04-01

    Full Text Available El objetivo general de este artículo es evaluar los efectos de la inseguridad ciudadana en el uso del espacio público. Dicha evaluación exige analizar dos relaciones que se establecen en el ámbito de la violencia: la relación entre victimización y percepción de inseguridad; y la que se establece entre actitudes sociales y resolución pacífica de conflictos nacionales. Para ello, se analizaron las variables victimización, percepción de inseguridad, uso del espacio físico, actitudes hacia el sistema institucional político y social y hacia la resolución de conflictos nacionales, y las posibles relaciones entre ellas. Los datos para realizar el estudio se obtuvieron por medio de una encuesta que se llevó a cabo con 1 200 personas de 18 y 70 años de edad residentes en la ciudad de Santiago. Los resultados indican que Santiago es una ciudad de habitantes con temor y que el aumento de la percepción de inseguridad de sus habitantes contrasta con el hecho de que las tasas de victimización se hayan mantenido, más o menos, constantes en los años que precedieron a la encuesta. El temor se relaciona con el abandono del espacio público físico y sociopolítico, así como con el refugio en los espacios y la vida privados. La actitud de resolver los conflictos por medios no pacíficos es frecuente y se asocia en mayor medida con la inseguridad, la actitud negativa hacia la democracia y la falta de expectativas sobre el futuro del país. Los resultados de este estudio respaldan la idea de que para superar el temor la gente tiende a adaptarse a la realidad adoptando una postura conformista, homogeneizando las creencias y los comportamientos, y sobreestimando la fuerza como medio para resolver las diferencias.

  7. Santiago, una ciudad con temor

    Directory of Open Access Journals (Sweden)

    Oviedo S. Enrique

    1999-01-01

    Full Text Available El objetivo general de este artículo es evaluar los efectos de la inseguridad ciudadana en el uso del espacio público. Dicha evaluación exige analizar dos relaciones que se establecen en el ámbito de la violencia: la relación entre victimización y percepción de inseguridad; y la que se establece entre actitudes sociales y resolución pacífica de conflictos nacionales. Para ello, se analizaron las variables victimización, percepción de inseguridad, uso del espacio físico, actitudes hacia el sistema institucional político y social y hacia la resolución de conflictos nacionales, y las posibles relaciones entre ellas. Los datos para realizar el estudio se obtuvieron por medio de una encuesta que se llevó a cabo con 1 200 personas de 18 y 70 años de edad residentes en la ciudad de Santiago. Los resultados indican que Santiago es una ciudad de habitantes con temor y que el aumento de la percepción de inseguridad de sus habitantes contrasta con el hecho de que las tasas de victimización se hayan mantenido, más o menos, constantes en los años que precedieron a la encuesta. El temor se relaciona con el abandono del espacio público físico y sociopolítico, así como con el refugio en los espacios y la vida privados. La actitud de resolver los conflictos por medios no pacíficos es frecuente y se asocia en mayor medida con la inseguridad, la actitud negativa hacia la democracia y la falta de expectativas sobre el futuro del país. Los resultados de este estudio respaldan la idea de que para superar el temor la gente tiende a adaptarse a la realidad adoptando una postura conformista, homogeneizando las creencias y los comportamientos, y sobreestimando la fuerza como medio para resolver las diferencias.

  8. Unión del Canal del Atazar con la Red de distribución de agua de Madrid (Plaza de Castilla (II

    Directory of Open Access Journals (Sweden)

    López de Berges y de los Santos, Emilio

    1967-05-01

    Full Text Available This paper describes the connecting conduit between the Atazar Canal, which finishes at the El Goloso reservoir, and the water distribution network of Madrid, whose reservoir is at the Plaza de Castilla. The main features of this conduit are: the initial stage of the conduit, the pipe itself, the valves and the final stage of the conduit. Work has been done quickly, and the use of one of the pipes saved Madrid from undergoing strong water restrictions during the summer months. The project was adjudicated by auction, and the price estimate was about 500 million pesetas, which gives some idea of the magnitude of the enterprise.En el presente artículo se describe el conducto de unión del Canal del Atazar —que finaliza en los depósitos de El Goloso— con la red de distribución de Madrid y los depósitos de la Plaza de Castilla. Los elementos más destacados de la conducción son: dispositivo de origen, conducción propiamente dicha, cámaras de válvulas y dispositivo final. Las obras se han llevado a buen ritmo, y la puesta en funcionamiento de una de sus tuberías evitó imponer severas restricciones al abastecimiento de la capital. Los trabajos se adjudicaron por el sistema de subasta con un presupuesto de ejecución material de unos 500 millones de pesetas, lo que da idea de su gran importancia.

  9. δ expansion applied to quantum electrodynamics

    International Nuclear Information System (INIS)

    Bender, C.M.; Boettcher, S.; Milton, K.A.

    1992-01-01

    A recently proposed technique known as the δ expansion provides a nonperturbative treatment of a quantum field theory. The δ-expansion approach can be applied to electrodynamics in such a way that local gauge invariance is preserved. In this paper it is shown that for electrodynamic processes involving only external photon lines and no external electron lines the δ expansion is equivalent to a fermion loop expansion. That is, the coefficient of δ n in the δ expansion is precisely the sum of all n-electron-loop Feynman diagrams in a conventional weak-coupling approximation. This equivalence does not extend to processes having external electron lines. When external electron lines are present, the δ expansion is truly nonperturbative and does not have a simple interpretation as a resummation of conventional Feynman diagrams. To illustrate the nonperturbative character of the δ expansion we perform a speculative calculation of the fermion condensate in the massive Schwinger model in the limit of large coupling constant

  10. pacientes con insuficiencia renal terminal

    Directory of Open Access Journals (Sweden)

    Karen Herrera Herrera

    2011-01-01

    Full Text Available La presente investigación fundamenta en la clínica psicoanalítica el estudio de dos casos de tres personas diagnosticadas con IRT que reciben tratamiento de hemodiálisis, en razón a que dadas las características y el aumento de los reportes que se presentan, ya esto se considera un problema de salud pública. El objetivo principal es describir las características dinámicas del proceso de duelo en pacientes con IRT en un centro de terapia renal de la ciudad de Cartagena. El procedimiento metodológico empleó un diseño de tipo cualitativo; la investigación se desarrolló con un diseño clínico mediante el estudio de casos, y fundamentada en la hermenéutica psicoanalítica. Todo esto respaldado en la historia clínica, la entrevista semiestructurada individual y familiar, los test proyectivos, test del dibujo de la figura humana Machover y TAT de Murray, para la debida integración de los análisis. Se concluye que predominan funciones fallidas de los progenitores y que son individuos provenientes de familias psicosomáticas, que utilizan la enfermedad para obtener un beneficio secundario.

  11. con bajo peso al nacer

    Directory of Open Access Journals (Sweden)

    Adriana Mora Antó

    2005-01-01

    Full Text Available Esta investigación dio cuenta de la relación entre el estilo de funcionamiento familiar, los patrones de crianza y las edades de desarrollo evolutivo en niños, nacidos con bajo peso. El estudio descriptivo correlacional se realizó con 41 niños y sus madres, aplicándose cuestionarios sobre funcionamiento familiar, prácticas de crianza y desarrollo infantil. Los resultados señalaron la existencia de un funcionamiento familiar caracterizado por una cohesión amalgamada y una adaptabilidad caótica, una disciplina complaciente, falta de control y de límites claros en la díada madre-hijo. Se trataba de familias monoparentales, donde la temprana edad de concepción, el madresolterismo y el apoyo de la familia extensa eran constantes. Las edades evolutivas registradas indicaron un desarrollo inferior a la edad cronológica, en la mayor parte de los casos; sin embargo, éstas tendieron a ser superiores al compararlas con la edades reales de los infantes. No se encontró una correlación estadísticamente significativa entre la edad de desarrollo y los diferentes factores del funcionamiento familiar para algunos de los rangos de edad considerados; sin embargo, no se lo descartó por completo, especialmente en lo referente al optimismo familiar

  12. Interbasis expansions for isotropic harmonic oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Shi-Hai, E-mail: dongsh2@yahoo.com [Departamento de Física, Escuela Superior de Física y Matemáticas, Instituto Politécnico Nacional, Edificio 9, Unidad Profesional Adolfo López Mateos, Mexico D.F. 07738 (Mexico)

    2012-03-12

    The exact solutions of the isotropic harmonic oscillator are reviewed in Cartesian, cylindrical polar and spherical coordinates. The problem of interbasis expansions of the eigenfunctions is solved completely. The explicit expansion coefficients of the basis for given coordinates in terms of other two coordinates are presented for lower excited states. Such a property is occurred only for those degenerated states for given principal quantum number n. -- Highlights: ► Exact solutions of harmonic oscillator are reviewed in three coordinates. ► Interbasis expansions of the eigenfunctions is solved completely. ► This is occurred only for those degenerated states for given quantum number n.

  13. Decennial plan of expansion 1994-2003

    International Nuclear Information System (INIS)

    1993-12-01

    The Decennial Plan of Expansion 1994-2003 of Electric sector reproduces the results of the studies occurred during the planning cycle of 1992/93 from the Coordinator Groups of the Electric System Planning. Based in the market forecasting, economic-financier and time for finishing the the works, the Decennial Plan of Expansion presents the schedule of the main generation and transmission works for the next ten years, the annual spend in generation, transmission and distribution, the costs of expansion and the evaluation of attending conditions in electric system in Brazil. (C.G.C.)

  14. Thermal expansion: Metallic elements and alloys. [Handbook

    Science.gov (United States)

    Touloukian, Y. S.; Kirby, R. K.; Taylor, R. E.; Desai, P. D.

    1975-01-01

    The introductory sections of the work are devoted to the theory of thermal expansion of solids and to methods for the measurement of the linear thermal expansion of solids (X-ray methods, high speed methods, interferometry, push-rod dilatometry, etc.). The bulk of the work is devoted to numerical data on the thermal linear expansion of all the metallic elements, a large number of intermetallics, and a large number of binary alloy systems and multiple alloy systems. A comprehensive bibliography is provided along with an index to the materials examined.

  15. Discrete expansions of continuum functions. General concepts

    International Nuclear Information System (INIS)

    Bang, J.; Ershov, S.N.; Gareev, F.A.; Kazacha, G.S.

    1979-01-01

    Different discrete expansions of the continuum wave functions are considered: pole expansion (according to the Mittag-Lefler theorem), Weinberg states. The general property of these groups of states is their completeness in the finite region of space. They satisfy the Schroedinger type equations and are matched with free solutions of the Schroedinger equation at the boundary. Convergence of expansions for the S matrix, the Green functions and the continuous-spectrum wave functions is studied. A new group of states possessing the best convergence is introduced

  16. Semiclassical expansions on and near caustics

    International Nuclear Information System (INIS)

    Meetz, K.

    1984-09-01

    We show that the standard WKB expansion can be generalized so that it reproduces the behavior of the wave function on and near a caustic in two-dimensional space time. The expansion is related to the unfolding polynomials of the elementary catastrophes occurring in two dimensions: the fold and the cusp catastrophe. The method determines control parameters and transport coefficients in a self-consistent way from differential equations and does not refer to the asymptotic expansion of Feynman path integrals. The lowest order equations are solved explicitly in terms of the multivalued classical action. The result is a generalized semiclassical approximation on and beyond a caustic. (orig.)

  17. Cosmic growth history and expansion history

    International Nuclear Information System (INIS)

    Linder, Eric V.

    2005-01-01

    The cosmic expansion history tests the dynamics of the global evolution of the universe and its energy density contents, while the cosmic growth history tests the evolution of the inhomogeneous part of the energy density. Precision comparison of the two histories can distinguish the nature of the physics responsible for the accelerating cosmic expansion: an additional smooth component--dark energy--or a modification of the gravitational field equations. With the aid of a new fitting formula for linear perturbation growth accurate to 0.05%-0.2%, we separate out the growth dependence on the expansion history and introduce a new growth index parameter γ that quantifies the gravitational modification

  18. Some Improved Nonperturbative Bounds for Fermionic Expansions

    Energy Technology Data Exchange (ETDEWEB)

    Lohmann, Martin, E-mail: marlohmann@gmail.com [Universita di Roma Tre, Dipartimento di Matematica (Italy)

    2016-06-15

    We reconsider the Gram-Hadamard bound as it is used in constructive quantum field theory and many body physics to prove convergence of Fermionic perturbative expansions. Our approach uses a recursion for the amplitudes of the expansion, discovered in a model problem by Djokic (2013). It explains the standard way to bound the expansion from a new point of view, and for some of the amplitudes provides new bounds, which avoid the use of Fourier transform, and are therefore superior to the standard bounds for models like the cold interacting Fermi gas.

  19. Oblique photon expansion of QED structure functions

    International Nuclear Information System (INIS)

    Chahine, C.

    1986-01-01

    In the oblique photon expansion, the collinear part of photon emission is summed up to all orders in perturbation theory. The number of oblique or non-collinear photons is the expansion order. Unlike in perturbation theory, every term of the expansion is both infrared finite and gauge invariant. The zero oblique photon contribution to the electromagnetic structure tensor in QED is computed in detail. The behaviors of the structure functions F1 and F2 are discussed in the soft and ultra-soft limits

  20. Improvement of Expansive Soils Using Chemical Stabilizers

    Science.gov (United States)

    Ikizler, S. B.; Senol, A.; Khosrowshahi, S. K.; Hatipoğlu, M.

    2014-12-01

    The aim of this study is to investigate the effect of two chemical stabilizers on the swelling potential of expansive soil. A high plasticity sodium bentonite was used as the expansive soil. The additive materials including fly ash (FA) and lime (L) were evaluated as potential stabilizers to decrease the swelling pressure of bentonite. Depending on the type of additive materials, they were blended with bentonite in different percentages to assess the optimum state and approch the maximum swell pressure reduction. According to the results of swell pressure test, both fly ash and lime reduce the swelling potential of bentonite but the maximum improvement occurs using bentonite-lime mixture while the swelling pressure reduction approaches to 49%. The results reveal a significant reduction of swelling potential of expansive soil using chemical stabilizers. Keywords: Expansive soil; swell pressure; chemical stabilization; fly ash; lime

  1. Applications of the large mass expansion

    International Nuclear Information System (INIS)

    Fleischer, J.; Kotikov, A.V.; ); Veretin, O.L.

    1998-01-01

    The method of the large mass expansion (LME) is investigated for selfenergy and vertex functions in two-loop order. It has the technical advantage that in many cases the expansion coefficients can be expressed analytically. As long as only one non-zero external momentum squared, q 2 , is involved also the Taylor expansion (TE) w.r.t. small q 2 yields high precision results in a domain sufficient for most applications. In the case of only one non-zero mass M and only one external momentum squared, the expansion w.r.t. q 2 /M 2 is identical for the TE and the LME. In this case the combined techniques yield analytic expressions for many diagrams, which are quite easy to handle numerically. (author)

  2. Surgically assisted rapid maxillary expansion in adults.

    Science.gov (United States)

    Pogrel, M A; Kaban, L B; Vargervik, K; Baumrind, S

    1992-01-01

    Twelve adults with maxillary width discrepancy of greater than 5 mm were treated by surgically assisted rapid maxillary expansion. The procedure consisted of bilateral zygomatic buttress and midpalatal osteotomies combined with the use of a tooth-borne orthopedic device postoperatively. Mean palatal expansion of 7.5 mm (range of 6 to 13 mm), measured in the first molar region, was achieved within 3 weeks in all patients. Expansion remained stable during the 12-month study period, with a mean relapse for the entire group of 0.88 +/- 0.48 mm. Morbidity was limited to mild postoperative discomfort. The results of this preliminary study indicated that surgically assisted rapid maxillary expansion is a safe, simple, and reliable procedure for achieving a permanent increase in skeletal maxillary width in adults. Further study is necessary to document the three-dimensional movements of the maxillary segments and long-term stability of the skeletal and dental changes.

  3. Expansion of the Neyveli lignite mine, India

    Energy Technology Data Exchange (ETDEWEB)

    Kasturi, T S [Neyveli Lignite Corp. Ltd., Tamil Nadu (India); Streck, W [Gold (O.) G.m.b.H. und Co. K.G., Koeln (Germany, F.R.)

    1979-08-01

    After giving a picture of the difficult winning conditions at the Neyveli open-cast lignite mine, the author states the reasons for the expansions of the open-cast mine and describes the necessary measures and machinery.

  4. Chemical graph-theoretic cluster expansions

    International Nuclear Information System (INIS)

    Klein, D.J.

    1986-01-01

    A general computationally amenable chemico-graph-theoretic cluster expansion method is suggested as a paradigm for incorporation of chemical structure concepts in a systematic manner. The cluster expansion approach is presented in a formalism general enough to cover a variety of empirical, semiempirical, and even ab initio applications. Formally such approaches for the utilization of chemical structure-related concepts may be viewed as discrete analogues of Taylor series expansions. The efficacy of the chemical structure concepts then is simply bound up in the rate of convergence of the cluster expansions. In many empirical applications, e.g., boiling points, chromatographic separation coefficients, and biological activities, this rate of convergence has been observed to be quite rapid. More note will be made here of quantum chemical applications. Relations to questions concerning size extensivity of energies and size consistency of wave functions are addressed

  5. Magnetized relativistic electron-ion plasma expansion

    Science.gov (United States)

    Benkhelifa, El-Amine; Djebli, Mourad

    2016-03-01

    The dynamics of relativistic laser-produced plasma expansion across a transverse magnetic field is investigated. Based on a one dimensional two-fluid model that includes pressure, enthalpy, and rest mass energy, the expansion is studied in the limit of λD (Debye length) ≤RL (Larmor radius) for magnetized electrons and ions. Numerical investigation conducted for a quasi-neutral plasma showed that the σ parameter describing the initial plasma magnetization, and the plasma β parameter, which is the ratio of kinetic to magnetic pressure are the key parameters governing the expansion dynamics. For σ ≪ 1, ion's front shows oscillations associated to the break-down of quasi-neutrality. This is due to the strong constraining effect and confinement of the magnetic field, which acts as a retarding medium slowing the plasma expansion.

  6. Wilson expansion in the minimal subtraction scheme

    International Nuclear Information System (INIS)

    Smirnov, V.A.

    1989-01-01

    The small distance expansion of the product of composite fields is constructed for an arbitrary renormalization procedure of the type of minimal subtraction scheme. Coefficient functions of the expansion are expressed explicitly through the Green functions of composite fields. The expansion has the explicity finite form: the ultraviolet (UV) divergences of the coefficient functions and composite fields are removed by the initial renormalization procedure while the infrared (IR) divergences in massless diagrams with nonvanishing contribution into the coefficient functions are removed by the R-operation which is the IR part of the R-operation. The latter is the generalization of the dimensional renormalization in the case when both UV and IR divergences are present. To derive the expansion, a ''pre-subtracting operator'' is introduced and formulas of the counter-term technique are exploited

  7. Treatment of divergent expansions in scattering theory

    International Nuclear Information System (INIS)

    Gersten, A.; Malin, S.

    1978-01-01

    One of the biggest obstacles in applying quantum field theory to realistic scattering problems are the divergencies of pertubation expansions for large coupling constants and the divergencies of partial wave expansions for massless particles exchanges. There exist, however, methods of summation of the divergent expansions which can lead to significant application in physics. In this paper we treat the problem of summing such expansions using three methods: (i) a generalization of the Pade approximation to the multivariable case. The suggested definition is unique and preserves unitarity. (ii) The summation of divergent partial waves for arbitrary spins. (iii) A successful application of a series inversion to the 3 P 1 nucleon-nucleon phase shift up to 200 MeV. (orig./WL) [de

  8. foundations on expansive soils introduction characteristic

    African Journals Online (AJOL)

    the swelling potential of expansive soils have been found to be: initial moisture content, .... behaviour of such huildin1?1>, it is difficult to give definite recommendations. ..... Structures in Black Cotton Soils, Central Building. Research Institute ...

  9. Secret-key expansion from covert communication

    Science.gov (United States)

    Arrazola, Juan Miguel; Amiri, Ryan

    2018-02-01

    Covert communication allows the transmission of messages in such a way that it is not possible for adversaries to detect that the communication is occurring. This provides protection in situations where knowledge that two parties are talking to each other may be incriminating to them. In this work, we study how covert communication can be used for a different purpose: secret key expansion. First, we show that any message transmitted in a secure covert protocol is also secret and therefore unknown to an adversary. We then propose a covert communication protocol where the amount of key consumed in the protocol is smaller than the transmitted key, thus leading to secure secret key expansion. We derive precise conditions for secret key expansion to occur, showing that it is possible when there are sufficiently low levels of noise for a given security level. We conclude by examining how secret key expansion from covert communication can be performed in a computational security model.

  10. Boson expansion theory in the seniority scheme

    International Nuclear Information System (INIS)

    Tamura, T.; Li, C.; Pedrocchi, V.G.

    1985-01-01

    A boson expansion formalism in the seniority scheme is presented and its relation with number-conserving quasiparticle calculations is elucidated. Accuracy and convergence are demonstrated numerically. A comparative discussion with other related approaches is given

  11. Molienda asistida con microondas de un coque metalúrgico

    Directory of Open Access Journals (Sweden)

    Ruisánchez, Esteban

    2014-06-01

    Full Text Available Metallurgical cokes are composed of graphitic carbon (s2p2 and different inorganic compounds with very different capacities to absorb microwave radiation. Moreover, due to the electric conductivity shown by the metallurgical cokes, microwave radiation produces electric arcs or microplasmas, which gives rise to hot spots. Therefore, when these cokes are irradiated with microwaves some parts of the particle experiment a rapid heating, while some others do not heat at all. As a result of the different expansion and stress caused by thermal the shock, small cracks and micro-fissures are produced in the particle. The weakening of the coke particles, and therefore an improvement of its grindability, is produced. This paper studies the microwave-assisted grinding of metallurgical coke and evaluates the grinding improvement and energy saving.Los coques metalúrgicos están compuestos mayoritariamente de carbono grafítico (s2p2 y diferentes compuestos inorgánicos con distintas capacidades de absorber la radiación de microondas. Cuando se irradian con microondas fragmentos de estos coques, algunas partes de las partículas experimentan un rápido calentamiento, mientras otras no. Además, debido a que el coque presenta una cierta conductividad eléctrica, al ser irradiados con microondas se producen de forma puntual arcos eléctricos o microplasmas, dando lugar a puntos muy calientes. Como consecuencia de las diferentes dilataciones y tensiones producidas por el choque térmico, se producen en las partículas pequeñas grietas y microfisuras. Esto produce una mayor fragilidad en las partículas de coque y un incremento en la molturabilidad de las mismas. En el presente artículo se estudia la molienda de coque asistida con microondas y se evalúan las mejoras en la molturabilidad y el ahorro de energía producido.

  12. Operator expansion at short distance in QCD

    Energy Technology Data Exchange (ETDEWEB)

    Hubschmid, W [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik; Mallik, S [Karlsruhe Univ. (T.H.) (Germany, F.R.). Inst. fuer Theoretische Kernphysik

    1982-11-01

    We present a method of calculating coefficients of gluon operators in the operator product expansion of two-point functions at short distance. It is based on a short-distance expansion of the singular part of the quark propagator in the gluon field, the latter being treated as external. We verify in full generality that the spin zero, gluon operator of dimension six does not contribute to the two-point functions of quark bilinears.

  13. Resolution of hydrodynamical equations for transverse expansions

    International Nuclear Information System (INIS)

    Hama, Y.; Pottag, F.W.

    1984-01-01

    The three-dimensional hydrodynamical expansion is treated with a method similar to that of Milekhin, but more explicit. Although in the final stage one have to appeal to numerical calculation, the partial differential equations governing the transverse expansions are treated without transforming them into ordinary equations with an introduction of averaged quantities. It is only concerned with the formalism and the numerical results will be given in the next paper. (Author) [pt

  14. The critical thermal expansion of gadolinium

    International Nuclear Information System (INIS)

    Robinson, K.; Lanchester, P.C.

    1978-01-01

    Measurements have been made of the critical thermal expansion of single crystals of gadolinium, prepared by solid state electrotransport processing. Although the expansion data can be fitted to a simple power law with exponents lambda + =-0.25, lambda - =-0.33, these values are not predicted by theory and a discontinuity remains at Tsub(c)=293.620 K. It is suggested that the results relate to a region of crossover to uniaxial dipolar behaviour. (Auth.)

  15. Cluster expansion for vacuum confining fields

    International Nuclear Information System (INIS)

    Simonov, Yu.A.

    1987-01-01

    Colored particle Green functions in vacuum background random fields are written as path integrals. Averaging over random fields is done using the cluster (cumulant) expansion. The existence of a finite correlation length for vacuum background fields is shown to produce the linear confinement, in agreement with the results, obtained with the help of averaged Hamiltonians. A modified form of cluster expansion for nonabelian fields is introduced using the path-ordered cumulants

  16. Synthesis, microstructure and thermal expansion studies

    Indian Academy of Sciences (India)

    Abstract. We report on the synthesis, microstructure and thermal expansion studies on Ca0.5+/2Sr0.5+/2Zr4P6−2Si2O24 ( = 0.00 to 1.00) system which belongs to NZP family of low thermal expansion ceramics. The ceramics synthesized by co-precipitation method at lower calcination and the sintering temperatures ...

  17. Composite asymptotic expansions and scaling wall turbulence.

    Science.gov (United States)

    Panton, Ronald L

    2007-03-15

    In this article, the assumptions and reasoning that yield composite asymptotic expansions for wall turbulence are discussed. Particular attention is paid to the scaling quantities that are used to render the variables non-dimensional and of order one. An asymptotic expansion is proposed for the streamwise Reynolds stress that accounts for the active and inactive turbulence by using different scalings. The idea is tested with the data from the channel flows and appears to have merit.

  18. A pedagogical approach to the Magnus expansion

    International Nuclear Information System (INIS)

    Blanes, S; Casas, F; Oteo, J A; Ros, J

    2010-01-01

    Time-dependent perturbation theory as a tool to compute approximate solutions of the Schroedinger equation does not preserve unitarity. Here we present, in a simple way, how the Magnus expansion (also known as exponential perturbation theory) provides such unitary approximate solutions. The purpose is to illustrate the importance and consequences of such a property. We suggest that the Magnus expansion may be introduced to students in advanced courses of quantum mechanics.

  19. Local behaviour of negative thermal expansion materials

    International Nuclear Information System (INIS)

    Fornasini, P.; Dalba, G.; Grisenti, R.; Purans, J.; Vaccari, M.; Rocca, F.; Sanson, A.

    2006-01-01

    EXAFS can represent a powerful probe of the local behaviour of negative thermal expansion (NTE) materials, thanks to the possibility of measuring the expansion of selected inter-atomic bonds and the perpendicular relative atomic displacements. The effectiveness of EXAFS for NTE studies is illustrated by a comparison of results recently obtained on germanium, CuCl and the cuprites Cu 2 O and Ag 2 O

  20. Resolution of hydrodynamical equations for transverse expansions

    International Nuclear Information System (INIS)

    Hama, Y.; Pottag, F.W.

    1985-01-01

    The three-dimensional hydrodynamical expansion is treated with a method similar to that of Milekhin, but more explicit. Although in the final stage we have to appeal to numerical calculation, the partial differential equations governing the transverse expansions are treated without transforming them into ordinary equations with an introduction of averaged quantities. The present paper is concerned with the formalism and the numerical results will be reported in another paper. (Author) [pt

  1. Stochastic quantization and 1/N expansion

    International Nuclear Information System (INIS)

    Brunelli, J.C.; Mendes, R.S.

    1992-10-01

    We study the 1/N expansion of field theories in the stochastic quantization method of Parisi and Wu using the supersymmetric functional approach. This formulation provides a systematic procedure to implement the 1/N expansion which resembles the ones used in the equilibrium. The 1/N perturbation theory for the non linear sigma model in two dimensions is worked out as an example. (author). 19 refs., 5 figs

  2. Foundations on Expansive Soils; A Review

    OpenAIRE

    Behzad Kalantari

    2012-01-01

    This study describes various types of foundation designs to be considered for structural engineering projects when the subsoil foundation consists of expansive or swelling soils. Among civil and architectural engineers expansive soils are known to be difficult foundation materials and problematic. These type of soils swell when they are subjected to moistures and shrink due to moisture loss. Because of this different behaviour upon wetting and drying, they cause minor to major structural dama...

  3. Thermal expansion behavior in fabricated cellular structures

    International Nuclear Information System (INIS)

    Oruganti, R.K.; Ghosh, A.K.; Mazumder, J.

    2004-01-01

    Thermal expansion behavior of cellular structures is of interest in applications where undesirable deformation and failure are caused by thermal expansion mismatch. This report describes the role of processing-induced effects and metallurgical aspects of melt-processed cellular structures, such as a bi-material structure designed to contract on heating, as well as uni-material structures of regular and stochastic topology. This bi-material structure utilized the principle of internal geometric constraints to alter the expansion behavior of the internal ligaments to create overall contraction of the structure. Homogenization design method was used to design the structure, and fabrication was by direct metal deposition by laser melting of powder in another part of a joint effort. The degree of porosity and grain size in the fabricated structure are characterized and related to the laser deposition parameters. The structure was found to contract upon heating over a short range of temperature subsequent to which normal expansion ensued. Also examined in this report are uni-material cellular structures, in which internal constraints arise from residual stress variations caused by the fabrication process, and thereby alter their expansion characteristics. A simple analysis of thermal strain of this material supports the observed thermal expansion behavior

  4. Boosting Government Performance with Open Source Software? – A Roadmap for Germany (¿Impulsar el desempeño del estado con software de código abierto? - Plan de trabajo para Alemania

    Directory of Open Access Journals (Sweden)

    Norbert Jesse

    2014-05-01

    Full Text Available English abstract Governments face a considerable pressure from all directions: budget restrictions, citizens’ expectations, demographical trends, local competition from surrounding areas – to name just a few. EGovernment is regarded as an imminent tool to tackle many of these challenges. Obviously, IT itself is object of increasing complexity, constant change and financial implications. This paper outlines how the federal German government follows a strategic roadmap for eGovernment by shaping the objectives and goals for IT expansion. We discuss the role of open source software and how new approaches for software development can turn the ambitious aims into reality. Spanish abstract Los gobiernos se enfrentan a una gran presión desde todas las direcciones: las restricciones presupuestarias, las expectativas de los ciudadanos, las tendencias demográficas, la competencia local- por nombrar algunos. El gobierno electrónico es considerado una herramienta inminente para abordar muchos de estos problemas. Obviamente, las TIC son objetos de complejidad creciente, cambio constante e implicaciones financieras. Este documento describe cómo el gobierno federal alemán sigue una hoja de ruta estratégica para el gobierno electrónico dándole forma a los objetivos y metas para su expansión tecnológica. Se discute el papel del software libre y cómo los nuevos enfoques para el desarrollo de software pueden convertir estos ambiciosos objetivos en realidad.

  5. Conversando con...Momoyo Kaijima

    OpenAIRE

    Gómez Alonso, Carlos; Álvarez Isidro, Eva; Torres Barchino, Ana

    2017-01-01

    [ES] Momoyo Kaijima es profesora en la Facultad de Arte y Diseño de la Universidad de Tsukuba en la Prefectura de Ibaraki y profesora visitante en la ETH de Zürich, en Royal Academy of Fine Arts, en Rice School of Architecture y en Harvard GSD. A lo largo de los años, Atelier Bow Wow ha colaborado con Krešimir Rogina, arquitecto de Zagreb y socio de la firma internacional Penezic&Rogina, en la realización del Grožnjan International Summer School of Architecture, siendo Rogina el nexo indispen...

  6. Thin foil expansion into a vacuum

    International Nuclear Information System (INIS)

    Mora, P.

    2005-01-01

    Plasma expansion into a vacuum is an old problem which has been renewed recently in various contexts: expansion of ultra-cold plasmas, cluster expansion, of dust grains, expansion of thin foils. In this presentation I will first discuss the physics of the expansion of a thin foil irradiated by an ultra-short ultra-intense laser pulse. The expansion results in the formation of high energy ions. For an infinitely steep plasma-vacuum interface the fastest ions are located in the outer part of the expansion and their velocity is given by ν m ax∼ 2 C s (In ω p it) where c s (Zk B T e /m i )''1/2 is the ion-acoustic velocity ω p i=(n e 0Ze''2/m i e 0 )''1/2 is the ion plasma frequency, n e 0 is the electron density in the unperturbed plasma, Z is the ion charge number. In the above expression, t is either the pulse duration or the effective acceleration time (in particular t∼L/2c s , where L is the width of the foil, when the electron cooling is taken into account). A salient characteristic of the expansion is the occurrence of a double layer structure and a peak of the accelerating electric field at the ion front. I will explain the origin of the peak and predict its temporal behavior. This peak has been diagnosed in recent experiments. I will also discuss the effect of a 2-temperatures electron distribution function on the expansion, showing the dominant role of the hot electron component. Finally I will discuss the occurrence of ion spikes in the expansion when the initial density profile is smooth. The ion spike is due to a wave breaking which cannot be handled in a satisfactory way by a fluid code and requires a kinetic description. A. simple collisionless particle code has been used to treat the evolution of the spike after the wave breaking and the results will be shown. (Author)

  7. Negative thermal expansion materials: technological key for control of thermal expansion.

    Science.gov (United States)

    Takenaka, Koshi

    2012-02-01

    Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over -30 ppm K -1 . Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.

  8. Negative thermal expansion materials: technological key for control of thermal expansion

    Directory of Open Access Journals (Sweden)

    Koshi Takenaka

    2012-01-01

    Full Text Available Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K−1. Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade.

  9. Negative thermal expansion materials: technological key for control of thermal expansion

    International Nuclear Information System (INIS)

    Takenaka, Koshi

    2012-01-01

    Most materials expand upon heating. However, although rare, some materials contract upon heating. Such negative thermal expansion (NTE) materials have enormous industrial merit because they can control the thermal expansion of materials. Recent progress in materials research enables us to obtain materials exhibiting negative coefficients of linear thermal expansion over −30 ppm K −1 . Such giant NTE is opening a new phase of control of thermal expansion in composites. Specifically examining practical aspects, this review briefly summarizes materials and mechanisms of NTE as well as composites containing NTE materials, based mainly on activities of the last decade. (topical review)

  10. Food irradiation - pros and cons

    International Nuclear Information System (INIS)

    1983-01-01

    The use of ionising radiation for food preservation is a much-disputed topic, both among experts and among consumers. Pros and cons of this issue were discussed in detail at the consumers' forum. Professor Dr. Johannes Friedrich Diehl, Director of the Institute for Biochemistry of the Food Research Centre, Karlsruhe, is a well-known supporter of the new method of food preservation; he sees advantages in the radiopreservation of food because, for example, losses due to inedibility are reduced, the danger of salmonellosis is decreased, just as the use of chemicals. He thinks this method to be without danger to health, shown by many years of experience. Opponents to food irradiation like Prof. Dr. Konrad Pfeilsticker, Professor for food science and food chemistry at the Bonn University deem the method to be unnecessary and raise the problem of qualitative changes caused in the food. In the course of the discussions, the pros and cons seemed to balance each other out. (orig./AJ) [de

  11. De paseo con los Bourbaki

    Directory of Open Access Journals (Sweden)

    Miquel Escudero

    2012-04-01

    Full Text Available Setenta y siete años después de la fundación del grupo Bourbaki, procedemos a una reflexión que puede ser útil para los estudiantes que acaso no sepan de su existencia, ni tan siquiera los de matemáticas. Sería interesante conocer que a este grupo se le debe el signo del vacío como conjunto. Con todo lo discutible que sea el método Bourbaki en su reinterpretación de la matemática, no cabe duda de su importante repercusión hasta el punto de que ha marcado una época. Hay un antes y un después tras su irrupción, ningún matemático de primera fila de la segunda mitad del siglo XX fue ajeno a su influjo, para encabezarlo o para reprobarlo. Comenzaron como una juvenil extravagancia, pero repleta de conocimientos y con decidida voluntad de aprehender el rigor de forma exhaustiva.

  12. Tratamiento del paciente con artrosis

    Directory of Open Access Journals (Sweden)

    Francisco Vargas Negrín

    2014-01-01

    Full Text Available El manejo terapéutico del paciente con artrosis tiene como objetivo disminuir la sintomatología dolorosa e inflamatoria, mejorar la capacidad funcional del paciente y la aplicación de intervenciones terapéuticas eficaces y lo más seguras posibles. Un enfoque centrado en el paciente implica su participación activa en el diseño del plan terapéutico y en la toma de decisiones informadas oportunas en todas las etapas de la enfermedad. La educación terapéutica, la actividad física y el ejercicio terapéutico junto con el control de peso, en caso de sobrepeso u obesidad, constituyen el núcleo central del tratamiento. Los autocuidados individuales y por los familiares son fundamentales en el control del día a día del paciente. El uso de terapias físicas, ayudas técnicas (bastón, etc. y de fármacos tipo analgésicos simples, opioides y antiinflamatorios tiene evidencias demostradas en el control del dolor, mejora la funcionalidad y la calidad de vida del paciente y una clara recomendación de uso en el tratamiento de la artrosis. La cirugía conservadora y la de reemplazo articular se indican en los casos en los que no se logran los objetivos terapéuticos en casos concretos.

  13. Expansion Under Climate Change: The Genetic Consequences.

    Science.gov (United States)

    Garnier, Jimmy; Lewis, Mark A

    2016-11-01

    Range expansion and range shifts are crucial population responses to climate change. Genetic consequences are not well understood but are clearly coupled to ecological dynamics that, in turn, are driven by shifting climate conditions. We model a population with a deterministic reaction-diffusion model coupled to a heterogeneous environment that develops in time due to climate change. We decompose the resulting travelling wave solution into neutral genetic components to analyse the spatio-temporal dynamics of its genetic structure. Our analysis shows that range expansions and range shifts under slow climate change preserve genetic diversity. This is because slow climate change creates range boundaries that promote spatial mixing of genetic components. Mathematically, the mixing leads to so-called pushed travelling wave solutions. This mixing phenomenon is not seen in spatially homogeneous environments, where range expansion reduces genetic diversity through gene surfing arising from pulled travelling wave solutions. However, the preservation of diversity is diminished when climate change occurs too quickly. Using diversity indices, we show that fast expansions and range shifts erode genetic diversity more than slow range expansions and range shifts. Our study provides analytical insight into the dynamics of travelling wave solutions in heterogeneous environments.

  14. Simplified Technique for Predicting Offshore Pipeline Expansion

    Science.gov (United States)

    Seo, J. H.; Kim, D. K.; Choi, H. S.; Yu, S. Y.; Park, K. S.

    2018-06-01

    In this study, we propose a method for estimating the amount of expansion that occurs in subsea pipelines, which could be applied in the design of robust structures that transport oil and gas from offshore wells. We begin with a literature review and general discussion of existing estimation methods and terminologies with respect to subsea pipelines. Due to the effects of high pressure and high temperature, the production of fluid from offshore wells is typically caused by physical deformation of subsea structures, e.g., expansion and contraction during the transportation process. In severe cases, vertical and lateral buckling occurs, which causes a significant negative impact on structural safety, and which is related to on-bottom stability, free-span, structural collapse, and many other factors. In addition, these factors may affect the production rate with respect to flow assurance, wax, and hydration, to name a few. In this study, we developed a simple and efficient method for generating a reliable pipe expansion design in the early stage, which can lead to savings in both cost and computation time. As such, in this paper, we propose an applicable diagram, which we call the standard dimensionless ratio (SDR) versus virtual anchor length (L A ) diagram, that utilizes an efficient procedure for estimating subsea pipeline expansion based on applied reliable scenarios. With this user guideline, offshore pipeline structural designers can reliably determine the amount of subsea pipeline expansion and the obtained results will also be useful for the installation, design, and maintenance of the subsea pipeline.

  15. Preliminary thermal expansion screening data for tuffs

    International Nuclear Information System (INIS)

    Lappin, A.R.

    1980-03-01

    A major variable in evaluating the potential of silicic tuffs for use in geologic disposal of heat-producing nuclear wastes is thermal expansion. Results of ambient-pressure linear expansion measurements on a group of tuffs that vary treatly in porosity and mineralogy are presente here. Thermal expansion of devitrified welded tuffs is generally linear with increasing temperature and independent of both porosity and heating rate. Mineralogic factors affecting behavior of these tuffs are limited to the presence or absence of cristobalite and altered biotite. The presence of cristobalite results in markedly nonlinear expansion above 200 0 C. If biotite in biotite-hearing rocks alters even slightly to expandable clays, the behavior of these tuffs near the boiling point of water can be dominated by contraction of the expandable phase. Expansion of both high- and low-porosity tuffs containing hydrated silicic glass and/or expandable clays is complex. The behavior of these rocks appears to be completely dominated by dehydration of hydrous phases and, hence, should be critically dependent on fluid pressure. Valid extrapolation of the ambient-pressure results presented here to depths of interest for construction of a nuclear-waste repository will depend on a good understanding of the interaction of dehydration rates and fluid pressures, and of the effects of both micro- and macrofractures on the response of tuff masss

  16. Mapping Brazilian Cropland Expansion, 2000-2013

    Science.gov (United States)

    Zalles, V.; Hansen, M.; Potapov, P.

    2016-12-01

    Brazil is one of the world's leading producers and exporters of agricultural goods. Despite undergoing significant increases in its cropland area in the last decades, it remains one of the countries with the most potential for further agricultural expansion. Most notably, the expansion in production areas of commodity crops such as soybean, corn, and sugarcane has become the leading cause of land cover conversion in Brazil. Natural land covers, such as the Amazon and Cerrado forests, have been negatively affected by this agricultural expansion, causing carbon emissions, biodiversity loss, altered water cycles, and many other disturbances to ecosystem services. Monitoring of change in cropland area extent can provide relevant information to decision makers seeking to understand and manage land cover change drivers and their impacts. In this study, the freely-available Landsat archive was leveraged to produce a large-scale, methodologically consistent map of cropland cover at 30 m. resolution for the entire Brazilian territory in the year 2000. Additionally, we mapped cropland expansion from 2000 to 2013, and used statistical sampling techniques to accurately estimate cropland area per Brazilian state. Using the Global Forest Change product produced by Hansen et al. (2013), we can disaggregate forest cover loss due to cropland expansion by year, revealing spatiotemporal trends that could advance our understanding of the drivers of forest loss.

  17. Hematoma Expansion Following Acute Intracerebral Hemorrhage

    Science.gov (United States)

    Brouwers, H. Bart; Greenberg, Steven M.

    2013-01-01

    Intracerebral hemorrhage, the most devastating form of stroke, has no specific therapy proven to improve outcome by randomized controlled trial. Location and baseline hematoma volume are strong predictors of mortality, but are non-modifiable by the time of diagnosis. Expansion of the initial hematoma is a further marker of poor prognosis that may be at least partly preventable. Several risk factors for hematoma expansion have been identified, including baseline ICH volume, early presentation after symptom onset, anticoagulation, and the CT angiography spot sign. Although the biological mechanisms of hematoma expansion remain unclear, accumulating evidence supports a model of ongoing secondary bleeding from ruptured adjacent vessels surrounding the initial bleeding site. Several large clinical trials testing therapies aimed at preventing hematoma expansion are in progress, including aggressive blood pressure reduction, treatment with recombinant factor VIIa guided by CT angiography findings, and surgical intervention for superficial hematomas without intraventricular extension. Hematoma expansion is so far the only marker of outcome that is amenable to treatment and thus a potentially important therapeutic target. PMID:23466430

  18. Considering FACTS in Optimal Transmission Expansion Planning

    Directory of Open Access Journals (Sweden)

    K. Soleimani

    2017-10-01

    Full Text Available The expansion of power transmission systems is an important part of the expansion of power systems that requires enormous investment costs. Since the construction of new transmission lines is very expensive, it is necessary to choose the most efficient expansion plan that ensures system security with a minimal number of new lines. In this paper, the role of Flexible AC Transmission System (FACTS devices in the effective operation and expansion planning of transmission systems is examined. Effort was taken to implement a method based on sensitivity analysis to select the optimal number and location of FACTS devices, lines and other elements of the transmission system. Using this method, the transmission expansion plan for a 9 and a 39 bus power system was performed with and without the presence of FACTS with the use of DPL environment in Digsilent software 15.1. Results show that the use of these devices reduces the need for new transmission lines and minimizes the investment cost.

  19. Thermal expansion of fibre-reinforced composites

    International Nuclear Information System (INIS)

    Schneider, B.

    1991-07-01

    The integral thermal expansion and the coefficient of thermal expansion (CTE) of carbon and Kevlar fibre-reinforced composites were measured with high accuracy from 5 K to room temperature. For this, a laser dilatometer and a sophisticated measuring procedure were used. CTE dependence on the orientation angle ω of angle-ply laminates was determined for samples with 5 different fibre alignments (UD 0deg, +/-30deg, +/-45deg, +/-60deg and UD 90deg). A high variability of the CTE with the orientation angle was shown. At angles of approximately +/-30deg even negative CTEs were found. With suitable reinforcing fibres being selected, their absolute values rose up to 30-100% of the positive CTEs of metals. Hence, composites of this type would be suitable as compensating materials in metal constructions where little thermal expansion is desired. To check the lamination theory, theoretical computations of the CTE- ω -dependence were compared with the measured values. An excellent agreement was found. Using the lamination theory, predictions about the expansion behaviour of angle-ply laminates can be made now, if the thermal and mechanical properties of the unidirectional (UD) laminate are known. Furthermore, it is possible to carry out simulation computations aimed at investigating the influence of a single parameter of the UD-laminate (e.g. shear modulus) on the expansion of the angle-ply laminate. (orig.) [de

  20. Cons ICARUS, TIGER and Fascism

    Directory of Open Access Journals (Sweden)

    Janez Vrečko

    2010-12-01

    Full Text Available Like the scientists of their time, Russian artists in the 1920s considered gravity the central problem – a view which points to the close harmony between modern physics and the avant-garde. It was only with the constructivist movement that the Icarus revolution grasped the principles of the “mobile philosophy” (3.651 which was almost at the same time recognised by modern physics as well. The static view of the world became obsolete, space and time were no longer absolute values. It was necessary to transcend Euclidean geometry, shake off the political ʻshackles on one’s hands’ and surrender to Lisicki’s imaginary space, where “At 2000 metres in the air / there is no more perspective” (Integrals 276.  Kosovel’s Icarus project accorded with Tatlin’s, and both of them accorded with the quintessential aims of the constructivist movement. It is no accident that Kosovel wished to name one of his poetry collections The Dream of Icarus. Poems on the Icarus theme, such as “Cons Icarus”, “Evacuation of the Spirit”, “Eh, Hey”, “A Heart in Alcohol” etc. belong to the group of Kosovel’s conses which follow his “mobile philosophy” (3.650 and “letters growing into space” (Int. 282.  The question “Man, do you want up in the air?” (Int. 128 will remain a question until the moment when man is finally ready to transcend the existing boundary and dive “beyond”. Hence Kosovel’s clear-cut contrast between the “green windows of an illuminated / express on a viaduct”, which moves horizontally and is, like a water current, subject to the earth’s gravity, and “the spirit in space”, whose direction of motion is “the perpendicular of the spirit”, atectonicity. “The spirit burns in space”: fire is an element that knows vertical movement alone, the only one of the elements to outgrow and transcend the earth’s gravity, therefore it is associated with another mythological figure important for

  1. Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

    Science.gov (United States)

    Shen, Fei-Ran; Kuang, Hao; Hu, Feng-Xia; Wu, Hui; Huang, Qing-Zhen; Liang, Fei-Xiang; Qiao, Kai-Ming; Li, Jia; Wang, Jing; Liu, Yao; Zhang, Lei; He, Min; Zhang, Ying; Zuo, Wen-Liang; Sun, Ji-Rong; Shen, Bao-Gen

    2017-10-01

    Materials with zero thermal expansion (ZTE) or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE) materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn-Co-Ge-In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE owing to a martensitic magnetostructural transition. The major finding is that the thermal expansion behavior can be totally controlled by modulating the crystallinity degree and phase transition from atomic scale. Self-compensation effect leads to ultra-low thermal expansion with a linear expansion coefficient as small as +0.68 × 10-6/K over a wide temperature range around room temperature. The present study opens an avenue to reach ZTE particularly from the large class of giant NTE materials based on phase transition.

  2. Ultra-low thermal expansion realized in giant negative thermal expansion materials through self-compensation

    Directory of Open Access Journals (Sweden)

    Fei-Ran Shen

    2017-10-01

    Full Text Available Materials with zero thermal expansion (ZTE or precisely tailored thermal expansion are in urgent demand of modern industries. However, the overwhelming majority of materials show positive thermal expansion. To develop ZTE or negative thermal expansion (NTE materials as compensators has become an important challenge. Here, we present the evidence for the realization of ultra-low thermal expansion in Mn–Co–Ge–In particles. The bulk with the Ni2In-type hexagonal structure undergoes giant NTE owing to a martensitic magnetostructural transition. The major finding is that the thermal expansion behavior can be totally controlled by modulating the crystallinity degree and phase transition from atomic scale. Self-compensation effect leads to ultra-low thermal expansion with a linear expansion coefficient as small as +0.68 × 10−6/K over a wide temperature range around room temperature. The present study opens an avenue to reach ZTE particularly from the large class of giant NTE materials based on phase transition.

  3. Establecimiento del cálculo del diámetro de cresta exterior de un engranaje cónico con técnicas de grafos. // Procedure for the calculation of outer tip diameter on straight bevel gear by means of graphs technique.

    Directory of Open Access Journals (Sweden)

    G. González Rey

    2007-09-01

    Full Text Available Mediante un modelo matemático son dadas las principales relaciones entre los parámetros geométricos básicos requeridosen la evaluación del diámetro de cresta exterior de un engranaje ortogonal de ruedas cónicas con dientes rectos y suma decorrecciones radiales iguales a cero. Adicionalmente, serán brindados algunos resultados que asocian la correspondenciaentre una geometría racional y la capacidad de carga de un engranaje cónico con restricciones del diámetro de crestaexterior. Para la determinación de los procedimientos de cálculo, los problemas planteados sobre los modelos matemáticoshan sido serán representados por medio de grafos bicromáticos.Palabras claves: Engranajes cónicos, diseño racional, modelo matemático._______________________________________________________________________________Abstract:By means of a mathematical model, the main relations for the evaluation of the outer tip diameter on straight bevelgear with sum of the profile shift coefficients equal to zero are given. Additionally, some results associated with arational geometry and high load capacities of straight bevel gear with restrictions in the outer tip diameter arepresented. For the determination of the calculation procedures based on mathematical models was used thetechnique of representation by means of graphs.Key words: Straight bevel gear, rational design, mathematical models, graphs technique.

  4. Supersonic expansion of argon into vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Habets, A H.M.

    1977-01-21

    A theoretical description of a free supersonic expansion process is given. Three distinct regions in the expansion are discussed, namely the continuum region, the gradual transition to the collisionless regime, and the free-molecular-flow stage. Important topics are the peaking-factor formalism, the thermal-conduction model, and the virtual-source formalism. The formation of the molecular beam from the expansion and condensation phenomena occurring in the expanding gas are discussed. The molecular beam machine used in the measurements is described and special attention is given to the cryopumps used in the supersonic sources as well as to the time-of-flight analysis of the molecular beam velocity distributions. Finally, the processing of experimental data is discussed, particularly the least-squares determination of best-fit representations of the measurements.

  5. Origami structures for tunable thermal expansion

    Science.gov (United States)

    Boatti, Elisa; Bertoldi, Katia

    Materials with engineered thermal expansion, capable of achieving targeted and extreme area/volume changes in response to variations in temperature, are important for a number of aerospace, optical, energy, and microelectronic applications. While most of the proposed structures with tunable coefficient of thermal expansion consist of bi-material 2D or 3D lattices, here we propose a periodic metastructure based on a bilayer Miura-Ori origami fold. We combine experiments and simulations to demonstrate that by tuning the geometrical and mechanical parameters an extremely broad range of thermal expansion coefficients can be obtained, spanning both negative and positive values. Additionally, the thermal properties along different directions can be adjusted independently. Differently from all previously reported systems, the proposed structure is non-porous.

  6. Radial expansion for spinning conformal blocks

    CERN Document Server

    Costa, Miguel S.; Penedones, João; Trevisani, Emilio

    2016-07-12

    This paper develops a method to compute any bosonic conformal block as a series expansion in the optimal radial coordinate introduced by Hogervorst and Rychkov. The method reduces to the known result when the external operators are all the same scalar operator, but it allows to compute conformal blocks for external operators with spin. Moreover, we explain how to write closed form recursion relations for the coefficients of the expansions. We study three examples of four point functions in detail: one vector and three scalars; two vectors and two scalars; two spin 2 tensors and two scalars. Finally, for the case of two external vectors, we also provide a more efficient way to generate the series expansion using the analytic structure of the blocks as a function of the scaling dimension of the exchanged operator.

  7. Thermal expansion of quaternary nitride coatings

    Science.gov (United States)

    Tasnádi, Ferenc; Wang, Fei; Odén, Magnus; Abrikosov, Igor A.

    2018-04-01

    The thermal expansion coefficient of technologically relevant multicomponent cubic nitride alloys are predicted using the Debye model with ab initio elastic constants calculated at 0 K and an isotropic approximation for the Grüneisen parameter. Our method is benchmarked against measured thermal expansion of TiN and Ti(1-x)Al x N as well as against results of molecular dynamics simulations. We show that the thermal expansion coefficients of Ti(1-x-y)X y Al x N (X  =  Zr, Hf, Nb, V, Ta) solid solutions monotonously increase with the amount of alloying element X at all temperatures except for Zr and Hf, for which they instead decrease for y≳ 0.5 .

  8. On a generalized oscillator system: interbasis expansions

    Energy Technology Data Exchange (ETDEWEB)

    Kibler, M [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; Mardoyan, L G; Pogosyan, G S [Joint Inst. for Nuclear Research, Dubna (Russian Federation). Lab. of Theoretical Physics

    1997-12-31

    This article deals with a nonrelativistic quantum mechanical study of a dynamical system which generalizes the isotropic harmonic oscillator system in three dimensions. The Schroedinger equation for this generalized oscillator system is separable in spherical, cylindrical, and spheroidal (prolate and oblate) coordinates. The quantum mechanical spectrum of this system is worked out in some details. The problem of interbasis expansions of the wave functions is completely solved. The coefficients for the expansion of the cylindrical basis in terms of the spherical basis, and vice-versa, are found to be analytic continuations (to real values of their arguments) of Clebsch-Gordan coefficients for the group SU(2). The interbasis expansion coefficients for the prolate and oblate spheroidal bases in terms of the spherical or the cylindrical bases are shown to satisfy three-term recursion relations. Finally, a connection between the generalized oscillator system (projected on the z-line) and the Morse system (in one dimension) are discussed. 41 refs.,.

  9. Anisotropic thermal expansion in flexible materials

    Science.gov (United States)

    Romao, Carl P.

    2017-10-01

    A definition of the Grüneisen parameters for anisotropic materials is derived based on the response of phonon frequencies to uniaxial stress perturbations. This Grüneisen model relates the thermal expansion in a given direction (αi i) to one element of the elastic compliance tensor, which corresponds to the Young's modulus in that direction (Yi i). The model is tested through ab initio prediction of thermal expansion in zinc, graphite, and calcite using density functional perturbation theory, indicating that it could lead to increased accuracy for structurally complex systems. The direct dependence of αi i on Yi i suggests that materials which are flexible along their principal axes but rigid in other directions will generally display both positive and negative thermal expansion.

  10. On a generalized oscillator system: interbasis expansions

    International Nuclear Information System (INIS)

    Kibler, M.; Mardoyan, L.G.; Pogosyan, G.S.

    1996-01-01

    This article deals with a nonrelativistic quantum mechanical study of a dynamical system which generalizes the isotropic harmonic oscillator system in three dimensions. The Schroedinger equation for this generalized oscillator system is separable in spherical, cylindrical, and spheroidal (prolate and oblate) coordinates. The quantum mechanical spectrum of this system is worked out in some details. The problem of interbasis expansions of the wave functions is completely solved. The coefficients for the expansion of the cylindrical basis in terms of the spherical basis, and vice-versa, are found to be analytic continuations (to real values of their arguments) of Clebsch-Gordan coefficients for the group SU(2). The interbasis expansion coefficients for the prolate and oblate spheroidal bases in terms of the spherical or the cylindrical bases are shown to satisfy three-term recursion relations. Finally, a connection between the generalized oscillator system (projected on the z-line) and the Morse system (in one dimension) are discussed. 41 refs.,

  11. Supersonic expansion of argon into vacuum

    International Nuclear Information System (INIS)

    Habets, A.H.M.

    1977-01-01

    A theoretical description of a free supersonic expansion process is given. Three distinct regions in the expansion are discussed, namely the continuum region, the gradual transition to the collisionless regime, and the free-molecular-flow stage. Important topics are the peaking-factor formalism, the thermal-conduction model, and the virtual-source formalism. The formation of the molecular beam from the expansion and condensation phenomena occurring in the expanding gas are discussed. The molecular beam machine used in the measurements is described and special attention is given to the cryopumps used in the supersonic sources as well as to the time-of-flight analysis of the molecular beam velocity distributions. Finally, the processing of experimental data is discussed, particularly the least-squares determination of best-fit representations of the measurements

  12. Back Reaction And Local Cosmological Expansion Rate

    CERN Document Server

    Geshnizjani, G; Geshnizjani, Ghazal; Brandenberger, Robert

    2002-01-01

    We calculate the back reaction of cosmological perturbations on a general relativistic variable which measures the local expansion rate of the Universe. Specifically, we consider a cosmological model in which matter is described by a single field. We analyze back reaction both in a matter dominated Universe and in a phase of scalar field-driven chaotic inflation. In both cases, we find that the leading infrared terms contributing to the back reaction vanish when the local expansion rate is measured at a fixed value of the matter field which is used as a clock, whereas they do not appear to vanish if the expansion rate is evaluated at a fixed value of the background time. We discuss possible implications for more realistic models with a more complicated matter sector.

  13. Fare astronomia con piccoli telescopi

    CERN Document Server

    Gainer, Michael K

    2007-01-01

    Non sono necessariamente richiesti strumenti mastodontici per produrre risultati scientificamente validi nel campo dell’astronomia. Anche l’astrofilo dotato di un piccolo telescopio, con un diametro di soli 8-9 cm, può contribuire alla scienza del cielo realizzando utili osservazioni del Sole, della Luna, dei pianeti, delle comete, degli asteroidi, delle stelle doppie o variabili, delle nebulose e degli ammassi stellari. Il manuale di M.K. Gainer spiega quale sia la dotazione minima (un piccolo telescopio, un computer, una semplice fotocamera digitale), come utilizzarla, e quali siano le tecniche appropriate da adottare nelle osservazioni. Offre inoltre schemi per interpretare e ridurre i dati raccolti, nonché schede da compilare e da spedire ai centri di raccolta internazionali. Questo libro è il passaporto grazie al quale l’astrofilo può entrare a pieno titolo nel mondo affascinante della scienza astronomica.

  14. Longitudinal expansion of field line dipolarization

    Science.gov (United States)

    Saka, O.; Hayashi, K.

    2017-11-01

    We examine the substorm expansions that started at 1155 UT 10 August 1994 in the midnight sector focusing on the longitudinal (eastward) expansion of field line dipolarization in the auroral zone. Eastward expansion of the dipolarization region was observed in all of the H, D, and Z components. The dipolarization that started at 1155 UT (0027 MLT) from 260° of geomagnetic longitude (CMO) expanded to 351°(PBQ) in about 48 min. The expansion velocity was 0.03-0.04°/s, or 1.9 km/s at 62°N of geomagnetic latitude. The dipolarization region expanding to the east was accompanied by a bipolar event at the leading edge of the expansion in latitudes equatorward of the westward electrojet (WEJ). In the midnight sector at the onset meridian, the Magnetospheric Plasma Analyzer (MAP) on board geosynchronous satellite L9 measured electrons and ions between 10 eV and 40 keV. We conclude from the satellite observations that this dipolarization was characterized by the evolution of temperature anisotropies, an increase of the electron and ion temperatures, and a rapid change in the symmetry axis of the temperature tensor. The field line dipolarization and its longitudinal expansion were interpreted in terms of the slow MHD mode triggered by the current disruption. We propose a new magnetosphere-ionosphere coupling (MI-coupling) mechanism based on the scenario that transmitted westward electric fields from the magnetosphere in association with expanding dipolarization produced electrostatic potential (negative) in the ionosphere through differences in the mobility of collisional ions and collisionless electrons. The field-aligned currents that emerged from the negative potential region are arranged in a concentric pattern around the negative potential region, upward toward the center and downward on the peripheral.

  15. Eigenfunction expansion for fractional Brownian motions

    International Nuclear Information System (INIS)

    Maccone, C.

    1981-01-01

    The fractional Brownian motions, a class of nonstationary stochastic processes defined as the Riemann-Liouville fractional integral/derivative of the Brownian motion, are studied. It is shown that these processes can be regarded as the output of a suitable linear system of which the input is the white noise. Their autocorrelation is then derived with a study of their standard-deviation curves. Their power spectra are found by resorting to the nonstationary spectral theory. And finally their eigenfunction expansion (Karhunen-Loeve expansion) is obtained: the eigenfunctions are proved to be suitable Bessel functions and the eigenvalues zeros of the Bessel functions. (author)

  16. New dynamic system suggested for earth expansion

    Energy Technology Data Exchange (ETDEWEB)

    Fitzpatrick, J [Asuncion Nacional Univ. (Paraguay). Inst. de Ciencias

    1972-01-01

    It is here suggested that there may have been much more radioactive materials in the deep interior of the earth than bitherto supposed. Trapped heat being generated in the interior would provide a mechanism for earth expansion. An assumption of heat generation in the deep interior of the earth of the order of 0,5 X 10-13 calories per second, per cubic centimeter, would provide sufficient thermal expansion to account for approximately 0.1 mm. change in the radius of the earth per year.

  17. Large J expansion in ABJM theory revisited.

    Science.gov (United States)

    Dimov, H; Mladenov, S; Rashkov, R C

    Recently there has been progress in the computation of the anomalous dimensions of gauge theory operators at strong coupling by making use of the AdS/CFT correspondence. On the string theory side they are given by dispersion relations in the semiclassical regime. We revisit the problem of a large-charge expansion of the dispersion relations for simple semiclassical strings in an [Formula: see text] background. We present the calculation of the corresponding anomalous dimensions of the gauge theory operators to an arbitrary order using three different methods. Although the results of the three methods look different, power series expansions show their consistency.

  18. Near threshold expansion of Feynman diagrams

    International Nuclear Information System (INIS)

    Mendels, E.

    2005-01-01

    The near threshold expansion of Feynman diagrams is derived from their configuration space representation, by performing all x integrations. The general scalar Feynman diagram is considered, with an arbitrary number of external momenta, an arbitrary number of internal lines and an arbitrary number of loops, in n dimensions and all masses may be different. The expansions are considered both below and above threshold. Rules, giving real and imaginary part, are derived. Unitarity of a sunset diagram with I internal lines is checked in a direct way by showing that its imaginary part is equal to the phase space integral of I particles

  19. Thermal expansion of diamond at low temperatures.

    Science.gov (United States)

    Stoupin, Stanislav; Shvyd'ko, Yuri V

    2010-02-26

    Temperature variation of a lattice parameter of a synthetic diamond crystal (type IIa) was measured using high-energy-resolution x-ray Bragg diffraction in backscattering. A 2 order of magnitude improvement in the measurement accuracy allowed us to directly probe the linear thermal expansion coefficient at temperatures below 100 K. The lowest value measured was 2x10{-9} K-1. It was found that the coefficient deviates from the expected Debye law (T3) while no negative thermal expansion was observed. The anomalous behavior might be attributed to tunneling states due to low concentration impurities.

  20. Expansion of the whole wheat flour extrusion

    DEFF Research Database (Denmark)

    Cheng, Hongyuan; Friis, Alan

    2008-01-01

    A new model framework is proposed to describe the expansion of extrudates with extruder operating conditions based on dimensional analysis principle. The Buckingham pi dimensional analysis method is applied to form the basic structure of the model from extrusion process operational parameters. Us....... Using the Central Composite Design (CCD) method, whole wheat flour was processed in a twin-screw extruder with 16 trials. The proposed model can well correlate the expansion of the 16 trials using 3 regression parameters. The average deviation of the correlation is 5.9%....

  1. Testing the isotropy of the Hubble expansion

    OpenAIRE

    Migkas, K.; Plionis, M.

    2016-01-01

    Abstract: We have used the Union2.1 SNIa compilation to search for possible Hubble expansion anisotropies, dividing the sky in 9 solid angles containing roughly the same number of SNIa, as well as in two Galactic hemispheres. We identified only one sky region, containing 82 SNIa (~15% of total sample with z > 0.02), that indeed appears to share a Hubble expansion significantly different from the rest of the sample. However, this behaviour can be attributed to the joint "erratic" behaviour of ...

  2. Scenarios of Expansion to Electric Generation Capacity

    Directory of Open Access Journals (Sweden)

    José Somoza-Cabrera

    2017-06-01

    Full Text Available We show the building scenarios of expansion to electric generation capacity enough to supply the demand to 2050. We were using the LEAP facility (Long-range Energy Alternatives Planning System, to simulate dispatch of electricity at minimum cost. Finally, we show the cost-benefice analysis of the technologies availability, included externality and CO2 emission limited. However that we included the externals cost in this analysis, it results insufficient to closed gap between fossil and renewable technologies of electric generation. Nevertheless, in some opportunities the renewable options had very important participations in the minimal cost scenario of expansion.

  3. The Monetary Policy – Restrictive or Expansive?

    Directory of Open Access Journals (Sweden)

    Adam Szafarczyk

    2007-10-01

    Full Text Available The monetary policy plays an important role in macroeconomic policy of government. There is a question concerning type of this policy expansive or restrictive (easy or tidy monetary policy. Unfortunately, we have a lot of criteria. Each of them gives us other answer. So due to equitation of Irving Fisher we have dominantly expansive monetary policy. This same situation exists when we use nominal value of rediscount interest rate of central bank. Opposite result appears when we use real value of this interest rate or level of obligatory reserve. Taking under consideration liquidity on money market we know, that level of interest rate is too high.

  4. Towards finite density QCD with Taylor expansions

    International Nuclear Information System (INIS)

    Karsch, F.; Schaefer, B.-J.; Wagner, M.; Wambach, J.

    2011-01-01

    Convergence properties of Taylor expansions of observables, which are also used in lattice QCD calculations at non-zero chemical potential, are analyzed in an effective N f =2+1 flavor Polyakov quark-meson model. A recently developed algorithmic technique allows the calculation of higher-order Taylor expansion coefficients in functional approaches. This novel technique is for the first time applied to an effective N f =2+1 flavor Polyakov quark-meson model and the findings are compared with the full model solution at finite densities. The results are used to discuss prospects for locating the QCD phase boundary and a possible critical endpoint in the phase diagram.

  5. Expansion program is a challenging project

    International Nuclear Information System (INIS)

    Walker, G.L.

    1992-01-01

    This paper reports that construction is set to begin on the $1.5 billion PGT-PG and E Pipeline Expansion Project. It will consist of 691 miles of 42-in pipeline and 110 miles of 36-in. pipeline, to be built over 2 years. The project, which will transport additional supplies of natural gas to US West Coast markets, has its US regulatory approval in hand. On Oct. 16, 1991, the Federal Energy Regulatory Commission authorized Pacific Gas Transmission Co. to construct its Pacific Northwest segment of the expansion. Pacific Gas and Electric Co. received approval to build its California segment in late 1990 from the California Public Utilities Commission

  6. Strategic Expansion Models in Academic Radiology.

    Science.gov (United States)

    Natesan, Rajni; Yang, Wei T; Tannir, Habib; Parikh, Jay

    2016-03-01

    In response to economic pressures, academic institutions in the United States and their radiology practices, are expanding into the community to build a larger network, thereby driving growth and achieving economies of scale. These economies of scale are being achieved variously via brick-and-mortar construction, community practice acquisition, and partnership-based network expansion. We describe and compare these three expansion models within a 4-part framework of: (1) upfront investment; (2) profitability impact; (3) brand impact; and (4) risk of execution. Copyright © 2016 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  7. From greedy to lazy expansions and their driving dynamics

    NARCIS (Netherlands)

    Dajani, K.; Kraaikamp, C.

    2001-01-01

    In this paper we study the ergodic properties of non-greedy series expansions to non-integer bases β > 1. It is shown that the so-called 'lazy' expansion is isomorphic to the 'greedy' expansion. Furthermore, a class of expansions to base β > 1, β =2 Z, 'in between' the lazy and the greedy

  8. Parabolic cyclinder functions : examples of error bounds for asymptotic expansions

    NARCIS (Netherlands)

    R. Vidunas; N.M. Temme (Nico)

    2002-01-01

    textabstractSeveral asymptotic expansions of parabolic cylinder functions are discussedand error bounds for remainders in the expansions are presented. Inparticular Poincaré-type expansions for large values of the argument$z$ and uniform expansions for large values of the parameter areconsidered.

  9. Electrical Resistance Alloys and Low-Expansion Alloys

    DEFF Research Database (Denmark)

    Kjer, Torben

    1996-01-01

    The article gives an overview of electrical resistance alloys and alloys with low thermal expansion. The electrical resistance alloys comprise resistance alloys, heating alloys and thermostat alloys. The low expansion alloys comprise alloys with very low expansion coefficients, alloys with very low...... thermoelastic coefficients and age hardenable low expansion alloys....

  10. Edgeworth expansion for functionals of continuous diffusion processes

    DEFF Research Database (Denmark)

    Podolskij, Mark; Yoshida, Nakahiro

    This paper presents new results on the Edgeworth expansion for high frequency functionals of continuous diffusion processes. We derive asymptotic expansions for weighted functionals of the Brownian motion and apply them to provide the Edgeworth expansion for power variation of diffusion processes....... Our methodology relies on martingale embedding, Malliavin calculus and stable central limit theorems for semimartingales. Finally, we demonstrate the density expansion for studentized statistics of power variations.......This paper presents new results on the Edgeworth expansion for high frequency functionals of continuous diffusion processes. We derive asymptotic expansions for weighted functionals of the Brownian motion and apply them to provide the Edgeworth expansion for power variation of diffusion processes...

  11. Principles of Thermal Expansion in Feldspars

    Science.gov (United States)

    Hovis, Guy; Medford, Aaron; Conlon, Maricate; Tether, Allison; Romanoski, Anthony

    2010-05-01

    Following the recent thermal expansion work of Hovis et al. (1) on AlSi3 feldspars, we have investigated the thermal expansion of plagioclase, Ba-K, and Ca-K feldspar crystalline solutions. X-ray powder diffraction data were collected between room temperature and 925 °C on six natural plagioclase specimens ranging in composition from anorthite to oligoclase, the K-exchanged equivalents of these plagioclase specimens, and five synthetic Ba-K feldspars with compositions ranging from 25 to 99 mol % BaAl2Si2O8. The resulting thermal expansion coefficients (α) for volume have been combined with earlier results for end-member Na- and K-feldspars (2,3). Unlike AlSi3 feldspars, Al2Si2 feldspars, including anorthite and celsian from the present study plus Sr- and Pb-feldspar from other workers (4,5), show essentially constant and very limited thermal expansion, regardless of divalent cation size. In the context of structures where the Lowenstein rule (6) requires Al and Si to alternate among tetrahedra, the proximity of bridging Al-O-Si oxygen ions to divalent neighbors (ranging from 0 to 2) produces short Ca-O (or Ba-O) bonds (7,8) that apparently are the result of local charge-balance requirements (9). Gibbs et al. (10) suggest that short bonds such as these have a partially covalent character. This in turn stiffens the structure. Thus, for feldspar series with coupled substitution the change away from a purely divalent M-site occupant gives the substituting (less strongly bonded) monovalent cations increasingly greater influence on thermal expansion. Overall, then, thermal expansion in the feldspar system is well represented on a plot of α against room-temperature volume, where one sees a quadrilateral bounded by data for (A) AlSi3 feldspars whose expansion behavior is controlled largely by the size of the monovalent alkali-site occupant, (B) Al2Si2 feldspars whose expansion is uniformly limited by partially-covalent bonds between divalent M-site occupants and

  12. Depresion en pacientes con alteraciones del tiroides

    OpenAIRE

    Radanovic-Grguric´, Ljiljana; Filakovic´, Pavo; Barkic´, Jelena; Mandic´, Nikola; Karner, Ivan; Smoje, Juraj

    2003-01-01

    Nuestro estudio fue realizado en un grupo de 53 mujeres con disfunción tiroidea y 28 mujeres con depresión mayor. Empleamos la Escala de la Depresión de Hamilton, la Escala de Autoevaluación de la Depresión de Zung y la Escala sobre la Impresión Clínica Global. Los resultados del estudio demuestran que la mayoría de los pacientes con disfunción tiroidea se mostraron clínicamente significativos en cuanto al trastorno depresivo. Los episodios depresivos son más frecuentes en pacientes con hipot...

  13. Aprende Ajedrez con Rey - Parte 2

    OpenAIRE

    ESTÉVEZ MONTERO, RAÚL; Lloret Mauri, Jaime

    2016-01-01

    Es una pieza audiovisual creada con el objeto de atraer la atención de los niños de muy corta edad con el ajedrez y familiarizarlos con todas sus piezas y movimientos. Es una animación dirigida a un público infantil presentada por dibujos animados en 2D, en la que se ha intentado respetar en todo momento el argot de la comunidad ajedredística. En este video se presenta la segunda parte. Estévez Montero, R.; Lloret Mauri, J. (2016). Aprende Ajedrez con Rey - Parte 2. http://hdl.handle.net/1...

  14. Aprende Ajedrez con Rey - Parte 1

    OpenAIRE

    ESTÉVEZ MONTERO, RAÚL; Lloret Mauri, Jaime

    2016-01-01

    Es una pieza audiovisual creada con el objeto de atraer la atención de los niños de muy corta edad con el ajedrez y familiarizarlos con todas sus piezas y movimientos. Es una animación dirigida a un público infantil presentada por dibujos animados en 2D, en la que se ha intentado respetar en todo momento el argot de la comunidad ajedredística. En este video se presenta la primera parte. Estévez Montero, R.; Lloret Mauri, J. (2016). Aprende Ajedrez con Rey - Parte 1. http://hdl.handle.net/1...

  15. Eta-Expansion Does The Trick

    DEFF Research Database (Denmark)

    Danvy, Olivier; Malmkjær, Karoline; Palsberg, Jens

    1996-01-01

    -sum type. For the latter case, it enables “The Trick.” In this article, we extend Gomard and Jones' partial evaluator for the &lgr;-calculus, &lgr;-Mix, with products and disjoint sums; we point out how eta-expansion for (finite) disjoint sums enable The Trick; we generalize our earlier work by identifying...

  16. Eta-Expansion Does The Trick

    DEFF Research Database (Denmark)

    Danvy, Olivier; Malmkjær, Karoline; Palsberg, Jens

    1995-01-01

    -sum type. For the latter case, it enables “The Trick.” In this article, we extend Gomard and Jones' partial evaluator for the &lgr;-calculus, &lgr;-Mix, with products and disjoint sums; we point out how eta-expansion for (finite) disjoint sums enable The Trick; we generalize our earlier work by identifying...

  17. Thermal Expansion Properties of Aerospace Materials

    Science.gov (United States)

    Green, E. F.

    1969-01-01

    Thermal expansion properties of materials used in aerospace systems are compiled into a single handbook. The data, derived from experimental measurements supplemented by information from literature sources, are presented in charts and tables arranged in two sections, covering cryogenic and elevated temperatures.

  18. Cropland expansion in Brazil, 2000 to 2014

    Science.gov (United States)

    Zalles, V.; Hansen, M.; Potapov, P.; Stehman, S. V.; Tyukavina, A.; Pickens, A. H.; Okpa, C.; Aguilar, R.; John, N.; Chavez, S.

    2017-12-01

    Brazil has become a global leader in the production of commodity row crops such as soybean, sugarcane, cotton, and corn. Here, we employ 30m spatial resolution Landsat data to estimate cropland extent in the year 2000 and its subsequent expansion through 2014. A probability-based sample of reference data allows us to report unbiased estimates of national, biome, and state-scale area of crop expansion with associated uncertainties. We find an increase in Brazilian cropland extent from 26.0 Mha in 2000 to 46.1 Mha in 2014. The cropland frontier states of Maranhao, Tocantins, Piaui, Bahia (MATOPIBA), Mato Grosso, Mato Grosso do Sul, and Para all more than doubled in cropland extent. The states of Goias, Minas Gerais and Sao Paulo experienced >50% increases. The vast majority of expansion, 79%, occurred on repurposed pasture lands, and 20% from the conversion of natural vegetation. Area of converted Cerrado savannas was nearly 2.5 times that of Amazon forests, and accounted for over half of new cropland in MATOPIBA. Spatio-temporal dynamics of cropland expansion are reflected in market conditions, land use policies, and other factors. Continued extensification of cropland is a viable option across Brazil with attendant benefits for and challenges to development.

  19. Territorial expansion and primary state formation.

    Science.gov (United States)

    Spencer, Charles S

    2010-04-20

    A major research problem in anthropology is the origin of the state and its bureaucratic form of governance. Of particular importance for evaluating theories of state origins are cases of primary state formation, whereby a first-generation state evolves without contact with any preexisting states. A general model of this process, the territorial-expansion model, is presented and assessed with archaeological data from six areas where primary states emerged in antiquity: Mesoamerica, Peru, Egypt, Mesopotamia, the Indus Valley, and China. In each case, the evidence shows a close correspondence in time between the first appearance of state institutions and the earliest expansion of the state's political-economic control to regions lying more than a day's round-trip from the capital. Although additional research will add detail and clarity to the empirical record, the results to date are consistent with the territorial-expansion model, which argues that the success of such long-distance expansion not only demanded the bureaucratization of central authority but also helped provide the resources necessary to underwrite this administrative transformation.

  20. Thermal expansion absorbing structure for pipeline

    International Nuclear Information System (INIS)

    Nagata, Takashi; Yamashita, Takuya.

    1995-01-01

    A thermal expansion absorbing structure for a pipeline is disposed to the end of pipelines to form a U-shaped cross section connecting a semi-circular torus shell and a short double-walled cylindrical tube. The U-shaped longitudinal cross-section is deformed in accordance with the shrinking deformation of the pipeline and absorbs thermal expansion. Namely, since the central lines of the outer and inner tubes of the double-walled cylindrical tube deform so as to incline, when the pipeline is deformed by thermal expansion, thermal expansion can be absorbed by a simple configuration thereby enabling to contribute to ensure the safety. Then, the entire length of the pipeline can greatly be shortened by applying it to the pipeline disposed in a high temperature state compared with a method of laying around a pipeline using only elbows, which has been conducted so far. Especially, when it is applied to a pipeline for an FBR-type reactor, the cost for the construction of a facility of a primary systems can greater be reduced. In addition, it can be applied to a pipeline for usual chemical plants and any other structures requiring absorption of deformation. (N.H.)

  1. The asymptotic expansion method via symbolic computation

    OpenAIRE

    Navarro, Juan F.

    2012-01-01

    This paper describes an algorithm for implementing a perturbation method based on an asymptotic expansion of the solution to a second-order differential equation. We also introduce a new symbolic computation system which works with the so-called modified quasipolynomials, as well as an implementation of the algorithm on it.

  2. The Asymptotic Expansion Method via Symbolic Computation

    Directory of Open Access Journals (Sweden)

    Juan F. Navarro

    2012-01-01

    Full Text Available This paper describes an algorithm for implementing a perturbation method based on an asymptotic expansion of the solution to a second-order differential equation. We also introduce a new symbolic computation system which works with the so-called modified quasipolynomials, as well as an implementation of the algorithm on it.

  3. Discrete expansions of continuum wave functions

    International Nuclear Information System (INIS)

    Bang, J.; Ershov, S.N.; Gareev, F.A.; Kazacha, G.S.

    1980-01-01

    Different methods of expanding continuum wave functions in terms of discrete basis sets are discussed. The convergence properties of these expansions are investigated, both from a mathematical and a numerical point of view, for the case of potentials of Woods-Saxon and square well type. (orig.)

  4. Phase transition from strong-coupling expansion

    International Nuclear Information System (INIS)

    Polonyi, J.; Szlachanyi, K.

    1982-01-01

    Starting with quarkless SU(2) lattice gauge theory and using the strong-coupling expansion we calculate the action of the effective field theory which corresponds to the thermal Wilson loop. This effective action makes evident that the quark liberating phase transition traces back to the spontaneous breaking of a global Z(2) symmetry group. It furthermore describes both phases qualitatively. (orig.)

  5. On Learning Ring-Sum-Expansions

    DEFF Research Database (Denmark)

    Fischer, Paul; Simon, H. -U.

    1992-01-01

    The problem of learning ring-sum-expansions from examples is studied. Ring-sum-expansions (RSE) are representations of Boolean functions over the base {#123;small infinum, (+), 1}#125;, which reflect arithmetic operations in GF(2). k-RSE is the class of ring-sum-expansions containing only monomials...... of length at most k:. term-RSE is the class of ring-sum-expansions having at most I: monomials. It is shown that k-RSE, k>or=1, is learnable while k-term-RSE, k>2, is not learnable if RPnot=NP. Without using a complexity-theoretical hypothesis, it is proven that k-RSE, k>or=1, and k-term-RSE, k>or=2 cannot...... be learned from positive (negative) examples alone. However, if the restriction that the hypothesis which is output by the learning algorithm is also a k-RSE is suspended, then k-RSE is learnable from positive (negative) examples only. Moreover, it is proved that 2-term-RSE is learnable by a conjunction...

  6. Regulatory Holidays and Optimal Network Expansion

    NARCIS (Netherlands)

    Willems, Bert; Zwart, Gijsbert

    2016-01-01

    We model the optimal regulation of continuous, irreversible, capacity expansion, in a model in which the regulated network firm has private information about its capacity costs, investments need to be financed out of the firm’s cash flows from selling network access and demand is stochastic. If

  7. On the Convergence of the Virial Expansion

    NARCIS (Netherlands)

    Ramawadh, S.D.

    2015-01-01

    The virial expansion appears in statistical mechanics, an area where physics and mathematics intersect. Throughout this thesis we will mostly ignore the physics and mainly focus on the mathematical aspects. This is a deliberate choice, made for two reasons. Firstly, there are several books that

  8. The optimizied expansion method for wavefield extrapolation

    KAUST Repository

    Wu, Zedong; Alkhalifah, Tariq Ali

    2013-01-01

    , for inhomogeneous media, we face difficulties in dealing with the mixed space-wavenumber domain operator.In this abstract, we propose an optimized expansion method that can approximate this operator with its low rank representation. The rank defines the number

  9. Asymptotic expansions for the Gaussian unitary ensemble

    DEFF Research Database (Denmark)

    Haagerup, Uffe; Thorbjørnsen, Steen

    2012-01-01

    Let g : R ¿ C be a C8-function with all derivatives bounded and let trn denote the normalized trace on the n × n matrices. In Ref. 3 Ercolani and McLaughlin established asymptotic expansions of the mean value ¿{trn(g(Xn))} for a rather general class of random matrices Xn, including the Gaussian U...

  10. Analytic continuation and perturbative expansions in QCD

    Czech Academy of Sciences Publication Activity Database

    Caprini, I.; Fischer, Jan

    2002-01-01

    Roč. 24, - (2002), s. 127-135 ISSN 1434-6044 R&D Projects: GA MPO RP-4210/69 Institutional research plan: CEZ:AV0Z1010920 Keywords : perturbative expansion * quantum chromodynamics * infrared ambiguity * essential singularities Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 6.162, year: 2002

  11. A Pedagogical Approach to the Magnus Expansion

    Science.gov (United States)

    Blanes, S.; Casas, F.; Oteo, J. A.; Ros, J.

    2010-01-01

    Time-dependent perturbation theory as a tool to compute approximate solutions of the Schrodinger equation does not preserve unitarity. Here we present, in a simple way, how the "Magnus expansion" (also known as "exponential perturbation theory") provides such unitary approximate solutions. The purpose is to illustrate the importance and…

  12. Thermal Expansion Anomaly Regulated by Entropy

    Science.gov (United States)

    Liu, Zi-Kui; Wang, Yi; Shang, Shunli

    2014-11-01

    Thermal expansion, defined as the temperature dependence of volume under constant pressure, is a common phenomenon in nature and originates from anharmonic lattice dynamics. However, it has been poorly understood how thermal expansion can show anomalies such as colossal positive, zero, or negative thermal expansion (CPTE, ZTE, or NTE), especially in quantitative terms. Here we show that changes in configurational entropy due to metastable micro(scopic)states can lead to quantitative prediction of these anomalies. We integrate the Maxwell relation, statistic mechanics, and first-principles calculations to demonstrate that when the entropy is increased by pressure, NTE occurs such as in Invar alloy (Fe3Pt, for example), silicon, ice, and water, and when the entropy is decreased dramatically by pressure, CPTE is expected such as in anti-Invar cerium, ice and water. Our findings provide a theoretic framework to understand and predict a broad range of anomalies in nature in addition to thermal expansion, which may include gigantic electrocaloric and electromechanical responses, anomalously reduced thermal conductivity, and spin distributions.

  13. Instability of a planar expansion wave.

    Science.gov (United States)

    Velikovich, A L; Zalesak, S T; Metzler, N; Wouchuk, J G

    2005-10-01

    An expansion wave is produced when an incident shock wave interacts with a surface separating a fluid from a vacuum. Such an interaction starts the feedout process that transfers perturbations from the rippled inner (rear) to the outer (front) surface of a target in inertial confinement fusion. Being essentially a standing sonic wave superimposed on a centered expansion wave, a rippled expansion wave in an ideal gas, like a rippled shock wave, typically produces decaying oscillations of all fluid variables. Its behavior, however, is different at large and small values of the adiabatic exponent gamma. At gamma > 3, the mass modulation amplitude delta(m) in a rippled expansion wave exhibits a power-law growth with time alpha(t)beta, where beta = (gamma - 3)/(gamma - 1). This is the only example of a hydrodynamic instability whose law of growth, dependent on the equation of state, is expressed in a closed analytical form. The growth is shown to be driven by a physical mechanism similar to that of a classical Richtmyer-Meshkov instability. In the opposite extreme gamma - 1 gas with low . Exact analytical expressions for the growth rates are derived for both cases and favorably compared to hydrodynamic simulation results.

  14. Stakeholder Support for School Food Policy Expansions

    Science.gov (United States)

    Pettigrew, Simone; Pescud, Melanie; Donovan, Robert J.

    2012-01-01

    The aim of this study was to assess the extent to which parents and school-based stakeholders (principals, teachers, canteen managers and Parents & Citizen Committee presidents) are supportive of potential expansions to a new school food policy. Eight additional policy components elicited in preliminary focus groups with parents and 19 additional…

  15. Instability of a planar expansion wave

    International Nuclear Information System (INIS)

    Velikovich, A.L.; Zalesak, S.T.; Metzler, N.; Wouchuk, J.G.

    2005-01-01

    An expansion wave is produced when an incident shock wave interacts with a surface separating a fluid from a vacuum. Such an interaction starts the feedout process that transfers perturbations from the rippled inner (rear) to the outer (front) surface of a target in inertial confinement fusion. Being essentially a standing sonic wave superimposed on a centered expansion wave, a rippled expansion wave in an ideal gas, like a rippled shock wave, typically produces decaying oscillations of all fluid variables. Its behavior, however, is different at large and small values of the adiabatic exponent γ. At γ>3, the mass modulation amplitude δm in a rippled expansion wave exhibits a power-law growth with time ∝t β , where β=(γ-3)/(γ-1). This is the only example of a hydrodynamic instability whose law of growth, dependent on the equation of state, is expressed in a closed analytical form. The growth is shown to be driven by a physical mechanism similar to that of a classical Richtmyer-Meshkov instability. In the opposite extreme γ-1 -1/2 , and then starts to decrease. The mechanism driving the growth is the same as that of Vishniac's instability of a blast wave in a gas with low γ. Exact analytical expressions for the growth rates are derived for both cases and favorably compared to hydrodynamic simulation results

  16. Hole expansion test of third generation steels

    Science.gov (United States)

    Agirre, Julen; Mendiguren, Joseba; Galdos, Lander; de Argandoña, Eneko Sáenz

    2017-10-01

    The trend towards the implementation of new materials in the chassis of the automobiles is considerably making more complex the manufacturing of the components that built it up. In this scenario materials with higher strengths and lower formabilities are daily faced by tool makers and component producers what reduces the process windows and makes the forming processes to be in the limits of the materials. One of the concerns that tool makers must face during the definition of the tools is the expansion ratios that the holes in the sheet may reach before producing a breakage due to the stretching of the material (also known as edge cracks). For the characterization of such limits, a standard test, the hole expansion test, can be applied so that the limits of the material are known. At the present study, hole expansion tests of a third generation steel, Fortiform1050 with a thickness of 1.2 millimeters have been carried out and compared them to a mild steel, DX54D with a thickness of 0.6 millimeters. A comparison for each material in terms of technology used to punch the hole, mechanical punching vs laser cutting has also been conducted. In addition, the measurement technique (online measurement vs offline measurement) followed in the Hole Expansion Ratio (HER) identification has also been analyzed. Finally, differences between both materials and techniques are presented.

  17. Asymptotic behaviour of firmly non expansive sequences

    International Nuclear Information System (INIS)

    Rouhani, B.D.

    1993-04-01

    We introduce the notion of firmly non expansive sequences in a Banach space and present several results concerning their asymptotic behaviour extending previous results and giving an affirmative answer to an open question raised by S. Reich and I. Shafir. Applications to averaged mappings are also given. (author). 16 refs

  18. The stagnation of electric system expansion

    International Nuclear Information System (INIS)

    Santos, A.M. dos

    1989-01-01

    The main works in the Brazilian electric sector in 1988 is presented, mentioning the fault of financier resources. The electric power tariffs by a real economical cost are also cited, allowing some advantages that can resolve the investment problem in the electric power expansion. (author)

  19. Peruvian Higher Education: Expansions Amid Economic Crisis.

    Science.gov (United States)

    Post, David

    1991-01-01

    Development of the Peruvian university system is described, focusing on periods of rapid expansion. Enrollment declines in 1974-78 are analyzed in the context of the educational reform program of the military government. The 1983 new university law, following return to civilian government, and future prospects for higher education are discussed.…

  20. Form factor expansion for thermal correlators

    NARCIS (Netherlands)

    Pozsgay, B.; Takács, G.

    2010-01-01

    We consider finite temperature correlation functions in massive integrable quantum field theory. Using a regularization by putting the system in finite volume, we develop a novel approach (based on multi-dimensional residues) to the form factor expansion for thermal correlators. The first few terms

  1. Expansion patterns and parallaxes for planetary nebulae

    Science.gov (United States)

    Schönberner, D.; Balick, B.; Jacob, R.

    2018-02-01

    Aims: We aim to determine individual distances to a small number of rather round, quite regularly shaped planetary nebulae by combining their angular expansion in the plane of the sky with a spectroscopically measured expansion along the line of sight. Methods: We combined up to three epochs of Hubble Space Telescope imaging data and determined the angular proper motions of rim and shell edges and of other features. These results are combined with measured expansion speeds to determine individual distances by assuming that line of sight and sky-plane expansions are equal. We employed 1D radiation-hydrodynamics simulations of nebular evolution to correct for the difference between the spectroscopically measured expansion velocities of rim and shell and of their respective shock fronts. Results: Rim and shell are two independently expanding entities, driven by different physical mechanisms, although their model-based expansion timescales are quite similar. We derive good individual distances for 15 objects, and the main results are as follows: (i) distances derived from rim and shell agree well; (ii) comparison with the statistical distances in the literature gives reasonable agreement; (iii) our distances disagree with those derived by spectroscopic methods; (iv) central-star "plateau" luminosities range from about 2000 L⊙ to well below 10 000 L⊙, with a mean value at about 5000 L⊙, in excellent agreement with other samples of known distance (Galactic bulge, Magellanic Clouds, and K648 in the globular cluster M 15); (v) the central-star mass range is rather restricted: from about 0.53 to about 0.56 M⊙, with a mean value of 0.55 M⊙. Conclusions: The expansion measurements of nebular rim and shell edges confirm the predictions of radiation-hydrodynamics simulations and offer a reliable method for the evaluation of distances to suited objects. Results of this paper are based on observations made with the NASA/ESA Hubble Space Telescope in Cycle 16 (GO11122

  2. Cycle expansions: From maps to turbulence

    Science.gov (United States)

    Lan, Y.

    2010-03-01

    We present a derivation, a physical explanation and applications of cycle expansions in different dynamical systems, ranging from simple one-dimensional maps to turbulence in fluids. Cycle expansion is a newly devised powerful tool for computing averages of physical observables in nonlinear chaotic systems which combines many innovative ideas developed in dynamical systems, such as hyperbolicity, invariant manifolds, symbolic dynamics, measure theory and thermodynamic formalism. The concept of cycle expansion has a deep root in theoretical physics, bearing a close analogy to cumulant expansion in statistical physics and effective action functional in quantum field theory, the essence of which is to represent a physical system in a hierarchical way by utilizing certain multiplicative structures such that the dominant parts of physical observables are captured by compact, maneuverable objects while minor detailed variations are described by objects with a larger space and time scale. The technique has been successfully applied to many low-dimensional dynamical systems and much effort has recently been made to extend its use to spatially extended systems. For one-dimensional systems such as the Kuramoto-Sivashinsky equation, the method turns out to be very effective while for more complex real-world systems including the Navier-Stokes equation, the method is only starting to yield its first fruits and much more work is needed to enable practical computations. However, the experience and knowledge accumulated so far is already very useful to a large set of research problems. Several such applications are briefly described in what follows. As more research effort is devoted to the study of complex dynamics of nonlinear systems, cycle expansion will undergo a fast development and find wide applications.

  3. 216-B-3 expansion ponds closure plan

    Energy Technology Data Exchange (ETDEWEB)

    1994-10-01

    This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA.

  4. Thermal Expansion of Vacuum Plasma Sprayed Coatings

    Science.gov (United States)

    Raj, S V.; Palczer, A. R.

    2010-01-01

    Metallic Cu-8%Cr, Cu-26%Cr, Cu-8%Cr-1%Al, NiAl and NiCrAlY monolithic coatings were fabricated by vacuum plasma spray deposition processes for thermal expansion property measurements between 293 and 1223 K. The corrected thermal expansion, (DL/L(sub 0) varies with the absolute temperature, T, as (DL/L(sub 0) = A(T - 293)(sup 3) + BIT - 293)(sup 2) + C(T - 293) + D, where, A, B, C and D are thermal, regression constants. Excellent reproducibility was observed for all of the coatings except for data obtained on the Cu-8%Cr and Cu-26%Cr coatings in the first heat-up cycle, which deviated from those determined in the subsequent cycles. This deviation is attributed to the presence of residual stresses developed during the spraying of the coatings, which are relieved after the first heat-up cycle. In the cases of Cu-8%Cr and NiAl, the thermal expansion data were observed to be reproducible for three specimens. The linear expansion data for Cu-8% Cr and Cu-26%Cr agree extremely well with rule of mixture (ROM) predictions. Comparison of the data for the Cu-8%Cr coating with literature data for Cr and Cu revealed that the thermal expansion behavior of this alloy is determined by the Cu-rich matrix. The data for NiAl and NiCrAlY are in excellent agreement with published results irrespective of composition and the methods used for processing the materials. The implications of these results on coating GRCop-84 copper alloy combustor liners for reusable launch vehicles are discussed.

  5. 216-B-3 expansion ponds closure plan

    International Nuclear Information System (INIS)

    1994-10-01

    This document describes the activities for clean closure under the Resource Conservation and Recovery Act of 1976 (RCRA) of the 216-B-3 Expansion Ponds. The 216-B-3 Expansion Ponds are operated by the US Department of Energy, Richland Operations Office (DOE-RL) and co-operated by Westinghouse Hanford Company (Westinghouse Hanford). The 216-B-3 Expansion Ponds consists of a series of three earthen, unlined, interconnected ponds that receive waste water from various 200 East Area operating facilities. The 3A, 3B, and 3C ponds are referred to as Expansion Ponds because they expanded the capability of the B Pond System. Waste water (primarily cooling water, steam condensate, and sanitary water) from various 200 East Area facilities is discharged to the Bypass pipe (Project X-009). Water discharged to the Bypass pipe flows directly into the 216-B-3C Pond. The ponds were operated in a cascade mode, where the Main Pond overflowed into the 3A Pond and the 3A Pond overflowed into the 3C Pond. The 3B Pond has not received waste water since May 1985; however, when in operation, the 3B Pond received overflow from the 3A Pond. In the past, waste water discharges to the Expansion Ponds had the potential to have contained mixed waste (radioactive waste and dangerous waste). The radioactive portion of mixed waste has been interpreted by the US Department of Energy (DOE) to be regulated under the Atomic Energy Act of 1954; the dangerous waste portion of mixed waste is regulated under RCRA

  6. Plantas cubanas con efecto antiinflamatorio

    Directory of Open Access Journals (Sweden)

    Ada Ivis Regalado Veloz

    Full Text Available La actividad antiinflamatoria suscita gran interés científico en el área farmacológica, debido a que muchas enfermedades en su evolución cursan por procesos inflamatorios (artritis reumatoide, ateroesclerosis, cáncer, diabetes, gota, asma, dermatitis, trastornos neurodegenerativos y diversas dolencias menores. Las enfermedades inflamatorias constituyen un problema de salud importante, debido a la falta de medicamentos eficaces y seguros para su uso por periodos prolongados. Hoy en día se trabaja en la búsqueda de alternativas de antiinflamatorios más seguros, en el que las plantas medicinales, una de las formas más antiguas de tratamiento, constituyen una elección a considerar. En este trabajo se realizó una revisión bibliográfica, sobre especies de plantas que crecen en Cuba que le reportan propiedades farmacológicas como antinflamatorios. En la revisión de la literatura se utilizó la base de datos Medline (vía PubMed, así como revistas nacionales desde el periodo de 2000 hasta el presente, con las palabras claves "inflamación" y "plantas cubanas antiinflamatorias" o "actividad antiinflamatoria" y "plantas medicinales".

  7. Hospitalidad, con y sin papeles

    Directory of Open Access Journals (Sweden)

    Ana Paula Penchaszadeh

    Full Text Available Resumen El objetivo de este artículo es vincular el trabajo sobre el archivo de Jacques Derrida con la experiencia de la hospitalidad. Se intentará mostrar que, por un lado, se trata siempre de los papeles, de la legitimidad que éstos otorgan o no tanto a nivel filosófico (deseo de poseer los papeles que autoricen tal o cual decisión interpretativa, como a nivel político ("tener papeles" como el principio básico de todo derecho a tener derechos, de todo derecho a la comunidad. Mas también, por otro lado, se intentará pensar aquello que arruina la idea misma de tener o no tener (papeles, la idea de propiedad, aquello que hace imposible fundar una decisión o identidad en última instancia y, por ende, una soberanía, una frontera. La hospitalidad, la llegada inminente del otro, representa un desafío político y ético para la filosofía: pues no se trata de un saber, sino de una experiencia transformando el sustrato del nos-otros, del ser común.

  8. Itinerari Musicali con la Wiild

    Directory of Open Access Journals (Sweden)

    Elisabetta Nanni

    2013-03-01

    Full Text Available La Wiild, acronimo di Wiimote Lavagna Digitale, è uno strumento didattico che utilizza il telecomando della Wii, il famoso gioco della Nintendo, insieme a un software libero, rendendolo così estremamente versatile. Non vincolato a software proprietario, il suo utilizzo è legato alla capacità dell’insegnante di ripartire dalla didattica, dalle risorse selezionate e dall’epistemologia di ogni singola disciplina, trovando così nel proprio contesto un ruolo per le tecnologie. Il contributo presenta ipotesi di lavoro per l’educazione musicale nella scuola secondaria di primo grado che si sviluppano sia attraverso lo studio del rapporto suono/segno con affinità pittoriche e successiva codificazione grafica, sia attraverso un’attività di laboratorio in cui co-costruire percorsi storico-musicali. La Wiild diventerà davvero utile ed efficace nel momento in cui, affiancando le risorse selezionate dal docente, verrà utilizzata senza essere notata, giocando un ruolo di strumento tecnologico «normale e trasparente».

  9. Orientaciones pedagógicas para la inclusión de niños con autismo en el aula regular. Un apoyo para el docente

    Directory of Open Access Journals (Sweden)

    Aixa Rangel

    2017-01-01

    Full Text Available El objetivo de este ensayo de tipo documental analítico fue formular un conjunto de orientaciones educativas para la inclusión de niños con autismo en el aula regular, por cuanto hay que proporcionarles atención para que tengan una experiencia enriquecedora de aprendizaje, en virtud de lo cual es esencial que los docentes se apoyen en programas de actualización que los sensibilice y prepare para aplicar orientaciones educativas adecuadas. Estas, se formularon en función de los hallazgos encontrados en el análisis de los autores consultados,tomando en cuenta la triada: interacción social, comunicación e imaginación, así como el ambiente, las adaptaciones curriculares y el desarrollo de estrategias como guía para el docente. Se concluye en que más allá de formular políticas y medidas legales que legitimen los derechos de las personas con autismo, es necesario informar y sensibilizar a los docentes para que se apropien de la importancia del tema de la inclusión,permitiendo jugar con el mayor conocimiento y la innovación de estrategias que permitirán el desarrollo de las potencialidades en un ambiente armónico, tomando en cuenta sus necesidades y ritmo de aprendizaje. Las orientaciones pedagógicas aquí presentadas, si bien son apenas un pequeño grupo, conforman un referente para el establecimiento en el aula de metas adicionales a las planteadas por el sistema educativo, sin embargo cada docente mediante la investigación de estas y otras puede seguir construyéndolas y actualizándolas a partir de la práctica, de manera que se contextualicen a las características de cada caso en particular, considerando por supuesto, las oportunidades de crecimiento que le ofrece su entorno y atenuando las restricciones que este a su vez les impone

  10. Bases tratadas con cemento, en California

    Directory of Open Access Journals (Sweden)

    Chinchilla, M.

    1962-05-01

    Full Text Available El uso de bases tratadas con cemento para autopistas se inició en el Estado de California en 1938, empleándose para carreteras con determinadas condiciones de tráfico. Inicialmente, se especificó el uso obligatorio de plantas mezcladoras para asegurar el debido control de las proporciones adecuadas.

  11. Perturbation Expansion in Dynamical Nuclear Field Theory and Its Relation with Boson Expansion Theory : Nuclear Physics

    OpenAIRE

    Teruo, KISHIMOTO; Tetsuo, KAMMURI; Institute of Physics, University of Tsukuba; Department of Physics, Osaka University

    1990-01-01

    With the Dynamical Nuclear Field Theory (DNFT) in the Tamm-Dancoff representation we examine higher order corrections in the vibrational mode of a spherical nuclear system. Due to the effects of bubble diagrams, the perturbation expansion in terms of the unrenormalized coupling strength and boson energy fails at full self-consistency. On the other hand, it becomes applicable in the form of linked-cluster expansion when we use thses constants renormalized by the effect of bubble diagrams, in t...

  12. Defining chemical expansion: the choice of units for the stoichiometric expansion coefficient

    DEFF Research Database (Denmark)

    Marrocchelli, Dario; Chatzichristodoulou, Christodoulos; Bishop, Sean R.

    2014-01-01

    Chemical expansion refers to the spatial dilation of a material that occurs upon changes in its composition. When this dilation is caused by a gradual, iso-structural increase in the lattice parameter with composition, it is related to the composition change by the stoichiometric expansion coeffi...... are provided for changes in oxygen content in fluorite, perovskite, and Ruddlesden-Popper (K2NiF4) phase materials used in solid oxide fuel cells....

  13. Fuerza manual de adultos con discapacidad intelectual

    Directory of Open Access Journals (Sweden)

    Ruth Cabeza Ruiz

    2017-09-01

    Full Text Available Objetivo. Presentar una descripción de la fuerza de prensión manual de hombres y mujeres con discapacidad intelectual (DI y comparar los resultados con valores de referencia de otras personas con y sin discapacidad intelectual. Método. El presente trabajo es un estudio transversal observacional, financiado por la Fundación SAMU, en el que se evaluaron a 122 personas con DI (86 hombres y 36 mujeres durante el desarrollo de unas jornadas de carácter recreativo en las que participaron varias asociaciones de atención a este colectivo. La batería de test utilizada fue el Alpaha-Fit Test Battery for Adults. Resultados. Se presentan los resultados relacionados con las variables de fuerza del miembro superior (Hand Grip Strength por grupos de edad (20-24, 25- 29, 30-34, 35-39, 40-44, 45-49, 50-54, 55-59 años. Los datos muestran valores que oscilan desde los 31 kg en los hombres más jóvenes con DI hasta los 13.3 kg del grupo más maduro de mujeres. Estos hallazgos son similares a los valores de referencia de población con DI española. Sin embargo, son muy inferiores a los obtenidos por la población sin discapacidad de la misma edad. Conclusión. Los resultados evidencian el menor rendimiento de las personas con DI en pruebas de fuerza de prensión manual por lo que se hace evidente la necesidad de llevar a cabo programas de ejercicio físico o deporte con las personas con DI.

  14. Power system capacity expansion planning model considering carbon emissions constraints

    Directory of Open Access Journals (Sweden)

    Diego Adolfo Mejía Giraldo

    2012-01-01

    Full Text Available Este artículo presenta un modelo de planeamiento de expansión de la capacidad de sistemas de potencia considerando restricciones en emisiones de carbono. Además de los aspectos técnicos y económicos considerados usualmente en el proceso de planeamiento, se consideran dos políticas ambientales que consisten en el cobro de un impuesto y un límite anual a las emisiones de dióxido de carbono (CO2. Adicionalmente se ha incluido el retiro gradual de las plantas de generación ineficientes. Este abordaje garantiza una producción de electricidad más limpia en el sistema expandido a un costo relativamente bajo. El modelo propuesto considera la red de transmisión y es aplicado a un sistema de potencia de prueba de 4 regiones y a uno de 11 regiones para un horizonte de planeación de 20 años. Los resultados muestran decisiones de inversión prácticas en términos de sostenibilidad y costos.

  15. REGENERATIVE GAS TURBINES WITH DIVIDED EXPANSION

    DEFF Research Database (Denmark)

    Elmegaard, Brian; Qvale, Einar Bjørn

    2004-01-01

    Recuperated gas turbines are currently drawing an increased attention due to the recent commercialization of micro gas turbines with recuperation. This system may reach a high efficiency even for the small units of less than 100 kW. In order to improve the economics of the plants, ways to improve...... their efficiency are always of interest. Recently, two independent studies have proposed recuperated gas turbines to be configured with the turbine expansion divided, in order to obtain higher efficiency. The idea is to operate the system with a gas generator and a power turbine, and use the gas from the gas...... divided expansion can be advantageous under certain circumstances. But, in order for todays micro gas turbines to be competitive, the thermodynamic efficiencies will have to be rather high. This requires that all component efficiencies including the recuperator effectiveness will have to be high...

  16. Thermal expansion coefficient determination by CBED

    International Nuclear Information System (INIS)

    Angelini, P.; Bentley, J.

    1984-01-01

    The present application of CBED involves measurements of thermal-expansion coefficients by measurement of changes in HOLZ line positions as a function of temperature. Previous work on this subject was performed on Si at a constant accelerating voltage of 100 kV between about 90 and 600 K. Diffraction patterns were recorded and line shifts correlated to lattice parameter changes. Differences were noted between values determined by CBED and accepted thermal expansion values. Significant HOLZ line interactions and splitting occurring in the (111) patterns were noted to contribute to the differences. Preliminary measurements have been made on Al, Al 2 O 3 , and single-crystal tau (Ni/sub 20.3/Ti/sub 2.7/B 6 ). An example of changes in HOLZ lines present in (114) patterns for Al are shown and the effect of temperature on the position of lines in the pattern illustrated

  17. The delta expansion in zero dimensions

    International Nuclear Information System (INIS)

    Cho, H.T.; Milton, K.A.; Pinsky, S.S.; Simmons, L.M. Jr.

    1989-01-01

    The recently introduced δ-expansion (or logarithmic-expansion) technique for obtaining nonperturbative information about quantum field theories is reviewed in the zero-dimensional context. There, it is easy to study questions of analytic continuation that arise in the construction of the Feynman rules that generate the δ series. It is found that for six- and higher-point Green's functions, a cancellation occurs among the most divergent terms, and that divergences that arise from summing over an infinite number of internal lines are illusory. The numerical accuracy is studied in some detail: The δ series converges inside a circle of radius one for positive bare mass squared, and diverges if the bare mass squared is negative, but in all cases, low-order Pade approximants are extremely accurate. These general features are expected to hold in higher dimensions, such as four

  18. Ultimate load capacities of expansion anchor bolts

    International Nuclear Information System (INIS)

    Czarnecki, R.M.; Manrique, M.A.; Samaddar, S.K.

    1993-01-01

    A summary of available experimental expansion anchor bolt test data is presented. These data were collected as part of programs by the nuclear industry to address generic issues related to verification of seismic adequacy of equipment in nuclear power plants. Some of the data presented are suitable for use in seismic probabilistic risk assessments. For example, mean values of ultimate strength, along with their standard deviation and coefficients of variation, for a range of most typical expansion anchor bolt sizes are presented. Effects of interaction between shear and tension, edge distance, spacing, and cracking of the concrete are presented in a manner that is more suitable for use in deterministic evaluations. Related industry programs to derive anchor bolt capacities are briefly discussed. Recommendations for areas of further investigation are also presented

  19. Collisionless plasma expansion into a vacuum

    International Nuclear Information System (INIS)

    Denavit, J.

    1979-01-01

    Particle simulations of the expansion of a collisionless plasma into vacuum are presented. The cases of a single-electron-temperature plasma and of a two-electron-temperature plasma are considered. The results confirm the existence of an ion front and verify the general features of self-similar solutions behind this front. A cold electron front is clearly observed in the two-electron-temperatures case. The computations also show that for a finite electron-to-ion mass ratio, m/sub e//m/sub i/, the electron thermal velocity in the expansion region is not constant, but decreases approximately linearly with xi 0 -(γ-1) xi/2, and comparison with computer simulation results show that the constant γ-1 is proportional to (Zm/sub e//m/sub i/)atsup 1/2at, where Z is the ion charge number

  20. Off-diagonal expansion quantum Monte Carlo.

    Science.gov (United States)

    Albash, Tameem; Wagenbreth, Gene; Hen, Itay

    2017-12-01

    We propose a Monte Carlo algorithm designed to simulate quantum as well as classical systems at equilibrium, bridging the algorithmic gap between quantum and classical thermal simulation algorithms. The method is based on a decomposition of the quantum partition function that can be viewed as a series expansion about its classical part. We argue that the algorithm not only provides a theoretical advancement in the field of quantum Monte Carlo simulations, but is optimally suited to tackle quantum many-body systems that exhibit a range of behaviors from "fully quantum" to "fully classical," in contrast to many existing methods. We demonstrate the advantages, sometimes by orders of magnitude, of the technique by comparing it against existing state-of-the-art schemes such as path integral quantum Monte Carlo and stochastic series expansion. We also illustrate how our method allows for the unification of quantum and classical thermal parallel tempering techniques into a single algorithm and discuss its practical significance.

  1. Bond return predictability in expansions and recessions

    DEFF Research Database (Denmark)

    Engsted, Tom; Møller, Stig Vinther; Jensen, Magnus David Sander

    We document that over the period 1953-2011 US bond returns are predictable in expansionary periods but unpredictable during recessions. This result holds in both in-sample and out-of-sample analyses and using both univariate regressions and combination forecasting techniques. A simulation study...... but negative in recessions. The results are also consistent with tests showing that the expectations hypothesis of the term structure holds in recessions but not in expansions. However, the results for bonds are in sharp contrast to results for stocks showing that stock returns are predictable in recessions...... but not in expansions. Thus, our results indicate that there is not a common predictive pattern of stock and bond returns associated with the state of the economy....

  2. Expansion planning for electrical generating systems

    International Nuclear Information System (INIS)

    1984-01-01

    The guidebook outlines the general principles of electric power system planning in the context of energy and economic planning in general. It describes the complexities of electric system expansion planning that are due to the time dependence of the problem and the interrelation between the main components of the electric system (generation, transmission and distribution). Load forecasting methods are discussed and the principal models currently used for electric system expansion planning presented. Technical and economic information on power plants is given. Constraints imposed on power system planning by plant characteristics (particularly nuclear power plants) are discussed, as well as factors such as transmission system development, environmental considerations, availability of manpower and financial resources that may affect the proposed plan. A bibliography supplements the references that appear in each chapter, and a comprehensive glossary defines terms used in the guidebook

  3. Intrinsic thermal expansion of crystal defects

    International Nuclear Information System (INIS)

    Ganne, J.-P.

    1981-02-01

    Although the phenomenon of thermal expansion has long been known, the intrinsic thermal expansion coefficient (ITEC) βsub(d) of a point defect, derived from its formation volume vsub(d), has never been measured directly. The differential dilatometer by interferometry built by ASTY and GILDER is described. It has allowed βsub(d) to be measured for several defects. Vacancies and small interstitial loops were produced in aluminium by low temperature (20 K) fast neutron irradiation followed by an anneal up to the beginning of stage III (160 K). The very high value of the measured ratio βsub(d)/β 0 (12+-4) is comparable with a lattice statics calculated (42) value (11.5 0 [fr

  4. Polyhomogeneous expansions from time symmetric initial data

    Science.gov (United States)

    Gasperín, E.; Valiente Kroon, J. A.

    2017-10-01

    We make use of Friedrich’s construction of the cylinder at spatial infinity to relate the logarithmic terms appearing in asymptotic expansions of components of the Weyl tensor to the freely specifiable parts of time symmetric initial data sets for the Einstein field equations. Our analysis is based on the assumption that a particular type of formal expansions near the cylinder at spatial infinity corresponds to the leading terms of actual solutions to the Einstein field equations. In particular, we show that if the Bach tensor of the initial conformal metric does not vanish at the point at infinity then the most singular component of the Weyl tensor decays near null infinity as O(\\tilde{r}-3\\ln \\tilde{r}) so that spacetime will not peel. We also provide necessary conditions on the initial data which should lead to a peeling spacetime. Finally, we show how to construct global spacetimes which are candidates for non-peeling (polyhomogeneous) asymptotics.

  5. 6th International Symposium on Thermal Expansion

    CERN Document Server

    1978-01-01

    This 6th International Symposium on Thermal Expansion, the first outside the USA, was held on August 29-31, 1977 at the Gull Harbour Resort on Hecla Island, Manitoba, Canada. Symposium Chairman was Ian D. Peggs, Atomic Energy of Canada Limited, and our continuing sponsor was CINDAS/Purdue University. We made considerable efforts to broaden the base this year to include more users of expansion data but with little success. We were successful, however, in establishing a session on liquids, an area which is receiving more attention as a logical extension to the high-speed thermophysical property measurements on materials at temperatures close to their melting points. The Symposium had good international representation but the overall attendance was, disappointingly, relatively low. Neverthe­ less, this enhanced the informal atmosphere throughout the meeting with a resultant frank exchange of information and ideas which all attendees appreciated. A totally new item this year was the presentation of a bursary to ...

  6. Eta-expansion does The Trick

    DEFF Research Database (Denmark)

    Danvy, Olivier; Malmkjær, Karoline; Palsberg, Jens

    1996-01-01

    Partial-evaluation folklore has it that massaging one's source programs can make them specialize better. In Jones, Gomard, and Sestoft's recent textbook, a whole chapter is dedicated to listing such “binding-time improvements”: nonstandard use of continuation-passing style, eta-expansion, and a p......Partial-evaluation folklore has it that massaging one's source programs can make them specialize better. In Jones, Gomard, and Sestoft's recent textbook, a whole chapter is dedicated to listing such “binding-time improvements”: nonstandard use of continuation-passing style, eta...... across dynamic case expressions. This requirement precisely accounts for the nonstandard use of continuation-passing style encountered in partial evaluation. Eta-expansion thus acts as a uniform binding-time coercion between values and contexts, be they of function type, product type, or disjoint...

  7. Temporal quadratic expansion nodal Green's function method

    International Nuclear Information System (INIS)

    Liu Cong; Jing Xingqing; Xu Xiaolin

    2000-01-01

    A new approach is presented to efficiently solve the three-dimensional space-time reactor dynamics equation which overcomes the disadvantages of current methods. In the Temporal Quadratic Expansion Nodal Green's Function Method (TQE/NGFM), the Quadratic Expansion Method (QEM) is used for the temporal solution with the Nodal Green's Function Method (NGFM) employed for the spatial solution. Test calculational results using TQE/NGFM show that its time step size can be 5-20 times larger than that of the Fully Implicit Method (FIM) for similar precision. Additionally, the spatial mesh size with NGFM can be nearly 20 times larger than that using the finite difference method. So, TQE/NGFM is proved to be an efficient reactor dynamics analysis method

  8. Change in the pace of universe expansion

    International Nuclear Information System (INIS)

    Palanque-Delabrouille, N.; Yeche, C.

    2016-01-01

    During the first 8 billion years the universe expansion was slowed down by gravity, at that time the universe was made up mostly of ordinary matter. The accelerating expansion phase we know dates back to 6 billion years ago and now the content of the universe can be divided into: dark energy (73%), dark matter (23%), gas (3.6%) and stars, planets... (0.4%). Quasars which are among the most luminous objects of the universe and whose light can be detected even after having travelled through the universe for 12 billion years, can be used as markers of the matter all along the history of the universe. 3 international projects (SDSS, DESI and LSST) will study, in a complementary way, the period when dark energy overtook ordinary matter. (A.C.)

  9. Experiencias de haber crecido con un padre/madre con trastorno mental severo (TMS)

    OpenAIRE

    Vivanco B, Gabriela; Grandón F, Pamela

    2016-01-01

    Introducción. La experiencia de vivir con personas que presentan un Trastorno Mental Severo (TMS) es difícil para las familias, en especial para los hijos quienes han sido poco estudiados. El objetivo de la investigación fue conocer cómo la experiencia de haber vivido con un padre o madre con un trastorno mental severo influyó en la infancia, adolescencia y adultez joven de sus hijos e hijas. Método. Se analizan las experiencias de convivencia con un padre/madre con TMS en 10 hijos (6 hombres...

  10. Separable expansions for virtual states and resonances

    International Nuclear Information System (INIS)

    Adhikari, S.K.; Fonseca, A.C.; Tomio, L.

    1983-01-01

    Finite rank expansions for two- and three-body t matrices are analytically continued to the unphysical sheet of the complex energy plane associated with the lowest two-body scattering threshold in order to obtain the position and residue of the virtual state and resonance poles. The present method is applied to study the 1 S 0 virtual state of two nucleons, the Efimov virtual states of three identical bosons, and the doublet virtual state of three nucleons

  11. Asymptotic expansion of the Keesom integral

    International Nuclear Information System (INIS)

    Abbott, Paul C

    2007-01-01

    The asymptotic evaluation and expansion of the Keesom integral, K(a), is discussed at some length in Battezzati and Magnasco (2004 J. Phys. A: Math. Gen. 37 9677; 2005 J. Phys. A: Math. Gen. 38 6715). Here, using standard identities, it is shown that this triple integral can be reduced to a single integral from which the asymptotic behaviour is readily obtained using Laplace's method. (comment)

  12. The reference electricity expansion plan of Guatemala

    International Nuclear Information System (INIS)

    Santizo, Rodolfo

    2002-01-01

    This presentation prepared by the Deputy Minister of Energy and Mines overviews the following issues: description of electric power infrastructure, price markets, expansion plans, power and energy demand projections through 2010, including bussiness opportunities for private investment on geothermal and hidro electric power production and distribution market. This presentation is intended for private investors who could be interested in bussiness opportunities of energy generation market in Guatemala

  13. Reduction Expansion Synthesis for Magnetic Alloy Powders

    Science.gov (United States)

    2015-12-01

    in Figure 1, the Army was able to address its need for printable plastic components, thus enabling a reduction in the total quantity of spare...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited REDUCTION EXPANSION SYNTHESIS FOR...Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202–4302, and to the Office of Management and Budget, Paperwork Reduction Project

  14. Moments expansion densities for quantifying financial risk

    OpenAIRE

    Ñíguez, T.M.; Perote, J.

    2017-01-01

    We propose a novel semi-nonparametric distribution that is feasibly parameterized to represent the non-Gaussianities of the asset return distributions. Our Moments Expansion (ME) density presents gains in simplicity attributable to its innovative polynomials, which are defined by the difference between the nth power of the random variable and the nth moment of the density used as the basis. We show that the Gram-Charlier distribution is a particular case of the ME-type of densities. The latte...

  15. SIMMER analysis of SRI postdisassembly expansion experiments

    International Nuclear Information System (INIS)

    Bott, T.F.; Bell, C.R.

    1982-01-01

    Calculations of simulated postdisassembly expansions with SIMMER-II are compared to experimental data. The main features of the fluid motion are reproduced accurately. Good agreement is achieved for the important parameters of kinetic energy and impulse imparted to the vessel head. The most important calculated results are shown to be relatively insensitive to numerical modeling variations and uncertainties in many physical parameters. The geometric configuration of the upper internal structures is shown to affect significantly the vessel head impact energy and impulse

  16. Theory of thermal expansivity and bulk modulus

    International Nuclear Information System (INIS)

    Kumar, Munish

    2005-01-01

    The expression for thermal expansivity and bulk modulus, claimed by Shanker et al. to be new [Physica B 233 (1977) 78; 245 (1998) 190; J. Phys. Chem. Solids 59 (1998) 197] are compared with the theory of high pressure-high temperature reported by Kumar and coworkers. It is concluded that the Shanker formulation and the relations based on this are equal to the approach of Kumar et al. up to second order

  17. Electrochemical detection of DNA triplet repeat expansion

    Czech Academy of Sciences Publication Activity Database

    Fojta, Miroslav; Havran, Luděk; Vojtíšková, Marie; Paleček, Emil

    2004-01-01

    Roč. 126, č. 21 (2004), s. 6532-6533 ISSN 0002-7863 R&D Projects: GA AV ČR IAA4004402; GA AV ČR IBS5004355; GA AV ČR KJB4004302; GA AV ČR KSK4055109 Institutional research plan: CEZ:AV0Z5004920 Keywords : DNA triplet repeat expansion * PCR amplification * neurodegenerative diseases Subject RIV: BO - Biophysics Impact factor: 6.903, year: 2004

  18. Automation of a thermal expansion instrument

    Energy Technology Data Exchange (ETDEWEB)

    Holland, L.L.

    1979-03-01

    Automation of a thermal expansion instrument using a minicomputer system and with analog-to-digital converter inputs and flip-flop relay outputs is described. The necessary hardware link and the software were developed to allow equipment control, data acquisition, data reduction, and report generation by the minicomputer. The design of the automation allows non-programmers to run the experiment, reduce the data, and generate the report.

  19. Hubble expansion in a Euclidean framework

    International Nuclear Information System (INIS)

    Alfven, H.

    1979-01-01

    There now seems to be strong evidence for a non-cosmological interpretation of the QSO redshift - in any case, so strong that it is of interest to investigate the consequences. The purpose of this paper is to construct a model of the Hubble expansion which is as far as possible from the conventional Big Bang model without coming in conflict with any well-established observational results (while introducing no new laws of physics). This leads to an essentially Euclidean metagalactic model (see Table I) with very little mass outside one-third or half of the Hubble radius. The total kinetic energy of the Hubble expansion need only to be about 5% of the rest mass energy. Present observations support backwards in time extrapolation of the Hubble expansion to a 'minimum size galaxy' Rsub(m), which may have any value in 0 26 cm. Other arguments speak in favor of a size close to the upper value, say Rsub(m) = 10 26 cm (Table II). As this size is probably about 100 times the Schwarzschild limit, an essentially Euclidean description is allowed. The kinetic energy of the Hubble expansion may derive from an intense QSO-like activity in the minimum size metagalaxy, with an energy release corresponding to the annihilation of a few solar masses per galaxy per year. Some of the conclusions based on the Big Bang hypothesis are criticized and in several cases alternative interpretations are suggested. A comparison between the Euclidean and the conventional models is given in Table III. (orig.)

  20. Local product structure for expansive homeomorphisms

    OpenAIRE

    Artigue, Alfonso; Brum, Joaquin; Potrie, Rafael

    2008-01-01

    Let $f\\colon M\\to M$ be an expansive homeomorphism with dense topologically hyperbolic periodic points, $M$ a compact manifold. Then there is a local product structure in an open and dense subset of $M$. Moreover, if some topologically hyperbolic periodic point has codimension one, then this local product structure is uniform. In particular, we conclude that the homeomorphism is conjugated to a linear Anosov diffeomorphism of a torus.

  1. Mejorando la planificación de sistemas territoriales con optimización metaheurística

    Directory of Open Access Journals (Sweden)

    Roger Z. Ríos Mercado

    2015-01-01

    Full Text Available Este artículo tiene por objetivo ilustrar cómo la ciencia puede impactar positivamente en procesos de decisiones de carácter industrial. El problema consiste en encontrar una partición del conjunto total de unidades geográficas (bloques que minimice una única función de dispersión territorial. Esta medida de desempeño es equivalente a maximizar la compacidad de los territorios, es decir, obtener diseños donde ls unidades geográficas estén lo más cercanas entre sí. La solución debe satisfacer además otros requerimientos como equilibrar las distintas medidas de actividad entre los distintos territorios, así como contigüidad de territorios. Como resultado se tiene un modelo mono-objetivo de optimización combinatoria. Método: Para tal efecto, se presenta un método metaheurístico de solución, denominado GRASP, para la resolución de un problema de diseño de territorios comerciales, motivado por una aplicación real de una compañía de distribución de bebidas embotelladas. El método integra componentes de construcción de soluciones y de búsqueda local o mejora de las mismas que intentan explotar inteligentemente la estructura matemática del problema. Resultados: El algoritmo se ha evaluado en varios conjuntos de instancias generados aleatoriamente a partir de datos reales proporcionados por el socio industrial. Los resultados obtenidos indican la eficacia del método propuesto dado que, en tiempos de cómputo relativamente rápidos, pudieron obtenerse soluciones de calidad muy superior a la de las obtenidas por la empresa, tanto respecto a la medida de compacidad, como respecto a la satisfacción de todas las restricciones. Previo a abordar el trabajo, la empresa no podía encontrar solcuiones que satisfacieran grados de balence, por ejemplo, inferiores al 20%. EL método propuesto encuentra siempre soluciones factibles con desbalances menores al 5%. Conclusión: Se ha ilustrado cómo los problemas de toma de decisiones

  2. Theory of compression and expansion of hydrogels

    Energy Technology Data Exchange (ETDEWEB)

    Iwata, M. [Suzuka National College of Tech., Mie (Japan). Dept. of Industrial Chemistry; Koda, S.; Nomura, H. [Nagoya University, Nagoya (Japan). Dept. of Molecular Design and Engineering

    1999-10-01

    Compression and expansion processes of cross-linked sodium polyacrylate hydrogels under mechanical pressure were investigated. A packed spherical gel bed shows irreversible deformation when the applied pressure is decreased; the expansion behavior depends on the maximum pressure applied to the gel bed. The time required to attain a certain degree of deformation is directly proportional to the square of the total solid volume of the gel bed; this relation is very similar to that observed in expression or expansion processes of ordinary solid-liquid mixtures. The driving force of the deformation is an effective osmotic pressure gradient in the gel bed, where the effective osmotic pressure of the gel is the difference between the swelling pressure of the gel and the pressure applied to the gel. The flow rate of liquid through any gel layer can be expressed by Darcy's equation. The deformation ceases when the swelling pressure of each gel particle is equal to the applied pressure. Thus, the deformation of a packed gel bed can be recognized as a process of equalizing the swelling pressure distribution in the bed. (author)

  3. Renormalizations and operator expansion in sigma model

    International Nuclear Information System (INIS)

    Terentyev, M.V.

    1988-01-01

    The operator expansion (OPE) is studied for the Green function at x 2 → 0 (n(x) is the dynamical field ofσ-model) in the framework of the two-dimensional σ-model with the O(N) symmetry group at large N. As a preliminary step we formulate the renormalization scheme which permits introduction of an arbitrary intermediate scale μ 2 in the framework of 1/N expansion and discuss factorization (separation) of small (p μ) momentum region. It is shown that definition of composite local operators and coefficient functions figuring in OPE is unambiguous only in the leading order in 1/N expansion when dominant are the solutions with extremum of action. Corrections of order f(μ 2 )/N (here f(μ 2 ) is the effective interaction constant at the point μ 2 ) in composite operators and coefficient functions essentially depend on factorization method of high and low momentum regions. It is shown also that contributions to the power corrections of order m 2 x 2 f(μ 2 )/N in the Green function (here m is the dynamical mass-scale factor in σ-model) arise simultaneously from two sources: from the mean vacuum value of the composite operator n ∂ 2 n and from the hard particle contributions in the coefficient function of unite operator. Due to the analogy between σ-model and QCD the obtained result indicates theoretical limitations to the sum rule method in QCD. (author)

  4. Hausdorff dimension of unique beta expansions

    International Nuclear Information System (INIS)

    Kong, Derong; Li, Wenxia

    2015-01-01

    Given an integer N ⩾ 2 and a real number β > 1, let Γ β, N be the set of all x=∑ i=1 ∞ d i /β i with d i  ∈ {0, 1, ···, N − 1} for all i ⩾ 1. The infinite sequence (d i ) is called a β-expansion of x. Let U β,N be the set of all x's in Γ β,N which have unique β-expansions. We give explicit formula of the Hausdorff dimension of U β,N for β in any admissible interval [β L , β U ], where β L is a purely Parry number while β U is a transcendental number whose quasi-greedy expansion of 1 is related to the classical Thue–Morse sequence. This allows us to calculate the Hausdorff dimension of U β,N for almost every β > 1. In particular, this improves the main results of Gábor Kallós (1999, 2001). Moreover, we find that the dimension function f(β) = dim H U β,N fluctuates frequently for β ∈ (1, N). (paper)

  5. Leptodermous expansion of finite-nucleus incompressibility

    International Nuclear Information System (INIS)

    Nayak, R.C.

    1990-01-01

    We consider the influence of higher-order terms in the leptodermous expansion used to extract the incompressibility K v of infinite nuclear matter from data on the breathing mode of finite nuclei. The terms we calculate are the curvature term K cv A -2/3 , the surface-symmetry term K ss I 2 A -1/3 , the quartic volume-symmetry term K 4 I 4 , and a Coulomb-exchange term. Working within the framework of the scaling model we derive expressions for their coefficients in terms of quantities that are defined for infinite and semi-infinite nuclear matter. We calculate these coefficients for four different Skyrme-type forces, using the extended Thomas-Fermi (ETF) approximation. With the same forces we also calculate the incompressibility K (A, I) for a number of finite nuclei, fit the results to the leptodermous expansion, and thereby extract new results for the same coefficients. The comparison of the two calculations shows that the leptodermous expansion is converging rapidly. Of the new terms, the term K 4 I 4 is quite negligible, the curvature term should be included, and we discuss to what extent the other higher-order terms are significant. (orig.)

  6. Trace expansions for mixed boundary problems

    Energy Technology Data Exchange (ETDEWEB)

    Seeley, Robert T

    2002-01-01

    We discuss the heat trace expansion for a mixed boundary problem for the Laplace operator acting on sections of some bundle V over a manifold M of dimension d. The boundary is divided in two parts N{sub D} and N{sub N}, intersecting in a smooth submanifold {sigma}. Dirichlet conditions are imposed on N{sub D} - {sigma}, and Neumann conditions on N{sub N} - {sigma}. It turns out that it is also necessary to impose a condition along {sigma}. We then obtain an expansion of the trace of the heat operator with these boundary conditions, containing integrals of the usual terms over the interior and the two parts of the boundary, together with integrals over {sigma} of terms that are 'global' in certain operators on a semicircle. The first nonzero such term is computed; it involves the zeta function of an operator on the semicircle, and depends on the boundary condition along {sigma}. We find that no logarithmic terms occur in the expansion.

  7. Eta-Expansion Does The Trick

    DEFF Research Database (Denmark)

    Danvy, Olivier; Malmkjær, Karoline; Palsberg, Jens

    1995-01-01

    Partial-evaluation folklore has it that massaging one's source programs can make them specialize better. In Jones, Gomard, and Sestoft's recent textbook, a whole chapter is dedicated to listing such “binding-time improvements”: nonstandard use of continuation-passing style, eta-expansion, and a p......Partial-evaluation folklore has it that massaging one's source programs can make them specialize better. In Jones, Gomard, and Sestoft's recent textbook, a whole chapter is dedicated to listing such “binding-time improvements”: nonstandard use of continuation-passing style, eta...... across dynamic case expressions. This requirement precisely accounts for the nonstandard use of continuation-passing style encountered in partial evaluation. Eta-expansion thus acts as a uniform binding-time coercion between values and contexts, be they of function type, product type, or disjoint......-expansion, and a popular transformation called “The Trick.” We provide a unified view of these binding-time improvements, from a typing perspective. Just as a proper treatment of product values in partial evaluation requires partially static values, a proper treatment of disjoint sums requires moving static contexts...

  8. Spatial Linkage and Urban Expansion: AN Urban Agglomeration View

    Science.gov (United States)

    Jiao, L. M.; Tang, X.; Liu, X. P.

    2017-09-01

    Urban expansion displays different characteristics in each period. From the perspective of the urban agglomeration, studying the spatial and temporal characteristics of urban expansion plays an important role in understanding the complex relationship between urban expansion and network structure of urban agglomeration. We analyze urban expansion in the Yangtze River Delta Urban Agglomeration (YRD) through accessibility to and spatial interaction intensity from core cities as well as accessibility of road network. Results show that: (1) Correlation between urban expansion intensity and spatial indicators such as location and space syntax variables is remarkable and positive, while it decreases after rapid expansion. (2) Urban expansion velocity displays a positive correlation with spatial indicators mentioned above in the first (1980-1990) and second (1990-2000) period. However, it exhibits a negative relationship in the third period (2000-2010), i.e., cities located in the periphery of urban agglomeration developing more quickly. Consequently, the hypothesis of convergence of urban expansion in rapid expansion stage is put forward. (3) Results of Zipf's law and Gibrat's law show urban expansion in YRD displays a convergent trend in rapid expansion stage, small and medium-sized cities growing faster. This study shows that spatial linkage plays an important but evolving role in urban expansion within the urban agglomeration. In addition, it serves as a reference to the planning of Yangtze River Delta Urban Agglomeration and regulation of urban expansion of other urban agglomerations.

  9. El maltrato en las personas con discapacidad

    OpenAIRE

    Revuelta, Lucerga

    2014-01-01

    El maltrato no solo se realiza por acción sino también por omisión, la indiferencia hacia la persona con discapacidad es una forma de maltrato muy frecuente. Por ejemplo, ignorar y desatender las necesidades de la persona con discapacidad o, al contrario, la sobreprotección son maneras de maltrato. Cuando a un niño con discapacidad el padre o cuidador le hace todo, el niño se siente agredido pues le están incapacitando más de lo que su enfermedad ya lo hace.

  10. Hiperalgesia asociada al tratamiento con opioides

    OpenAIRE

    A. Gil Martín; M. Moreno García; J. Sánchez-Rubio Ferrández; T. Molina García

    2014-01-01

    La hiperalgesia inducida por opioides es una reacción paradójica caracterizada por una percepción intensificada de dolor relacionada con el uso de estos medicamentos en ausencia de progresión de la enfermedad o de síndrome de retirada. A diferencia de los casos de tolerancia, definida como pérdida de potencia analgésica durante el uso prolongado de opioides, no se produce mejoría con el escalado de dosis. La hiperalgesia inducida por opioides se ha manifestado en pacientes con dosis de manten...

  11. Tratamiento conservador en pacientes con retinoblastoma bilateral

    Directory of Open Access Journals (Sweden)

    Juan C. Suárez

    2008-11-01

    Full Text Available OBJETIVO: comparar el tratamiento convencional del retinoblastoma bilateral, usado hasta hace algunos años, consistente en radioterapia o enucleación bilateral, con el tratamiento conservador actual que incluye termoterapia transpupilar (TTT o TTT/quimioterapia al menos en un ojo, en niños con diagnóstico de retinoblastoma bilateral. DISEÑO: estudio retrospectivo descriptivo. MUESTRA: 20 pacientes con diagnóstico de retinoblastoma bilateral que consultaron al Hospital Universitario San Vicente de Paúl, de Medellín, Colombia, entre 1997 y 2007. MÉTODO: se hizo enucleación del ojo con el tumor de mayor tamaño. En el otro ojo se hizo tratamiento con TTT, con el láser diodo (810 nm, spot amplio, solo o combinado con otras terapias. RESULTADOS: se dividió a los pacientes en dos grupos: 16 pacientes (32 ojos en el grupo 1 tratados conservadoramente y 4 pacientes (8 ojos en el grupo 2 con tratamiento convencional. El rango de edad fue de 1-72 meses en el grupo 1 y de 1-12 meses en el grupo 2. El tiempo de seguimiento fue de 7-67 meses para el grupo 1 y de 13-73 meses para el grupo 2. En el grupo 1 se hizo enucleación de 16 ojos (50%, radioterapia externa de uno (3,1%, quimioterapia más termoterapia de 5 (15,6% y quimioterapia más termoterapia más crioterapia de 10 (31,3%. En todos los pacientes se logró preservar al menos un ojo. En el grupo 2, se enuclearon 7 ojos (87,5% y se hizo radioterapia externa más enucleación en un paciente (12.5%. Además, todos los pacientes recibieron quimioterapia. CONCLUSIÓN: la terapia conservadora actual consistente en tratamiento local (termoterapia, crioterapia o braquiterapia y quimiorreducción permite preservar al menos un ojo y en algunos casos de los dos, muchas veces con buena agudeza visual, en niños con retinoblastoma bilateral; se evitan así la enucleación bilateral y la radioterapia externa usada en el tratamiento convencional con todos sus efectos secundarios. La enucleación contin

  12. Paciente con tumor de cuerpo carotideo

    Directory of Open Access Journals (Sweden)

    Mariuska Forteza Sáez

    Full Text Available Los tumores de cuerpo carotideo (paragangliomas son neoplasias altamente vascularizadas, muy poco frecuentes y generalmente benignas, originadas en los quimiorreceptores del cuerpo carotideo. Se presenta el caso de un paciente de 54 años, con aumento de volumen cervical derecho, asintomático, con estudio preoperatorio y angiografía realizados por tomografía axial computarizada, que resultan compatibles con tumor de cuerpo carotideo. Se realiza disección subadventicial, informando la biopsia paraganglioma. El tumor fue completamente resecado, sin evidencia de recurrencia y sin complicaciones.

  13. The holonomy expansion: Invariants and approximate supersymmetry

    International Nuclear Information System (INIS)

    Jaffe, Arthur

    2000-01-01

    In this paper we give a new expansion, based on cyclicity of the trace, to study regularity properties of twisted expectations =Tr H (γU(θ)X(s)). Here X(s)=X 0 e -s 0 Q 2 X 1 e -s 1 Q 2 ...X k e -s k Q 2 is a product of operators X j , regularized by heat kernels e -s j Q 2 with s j >0. The twist groups γ(set-membership sign)Z 2 and U(θ)(set-membership sign)U(1) are commuting symmetries of Q 2 . The name ''holonomy expansion'' arises from picturing as a circular graph, with vertices in the graph representing the operators X j , in the order that they appear in the product, and the line-segment following X j representing the heat kernel e -s j Q 2 . The trace functional is cyclic, so the graph is circular. We generate our expansion by ''transporting'' a vertex X k around the circle, ending in its original position. We choose an X k that transforms under a one-dimensional representation of Z 2 xU(1). For θ in the complement of the discrete set γ sing (where the group Z 2 xU(1) acts trivially on X k ) we obtain an identity between the original expectation and some new expectations. We study an example from supersymmetric quantum mechanics, with a Dirac operator Q(λ) depending on a parameter λ and with a U(1) group of symmetries U(θ). We apply our expansion to invariants Z(λ;θ)=Z(Q(λ);θ) suggested by non-commutative geometry. These invariants are sums of expectations of the form above. We investigate this example as a first step toward developing an expansion to evaluate related invariants arising in supersymmetric quantum field theory. We establish differentiability of Z(λ; θ) in λ for λ(set-membership sign)(0,1] and show Z(λ; θ) is independent of λ. We wish to evaluate Z(λ; θ) at the endpoint λ=0, but Z(0; θ) is ill-defined. We regularize the endpoint, while preserving the U(θ)-symmetry, by replacing Q(λ) 2 with H(ε,λ)=Q(λ) 2 +ε 2 |z| 2 . The regularized function Z(ε, λ; θ) depends on all three variables ε, λ, θ; for fixed θ, it

  14. A summation procedure for expansions in orthogonal polynomials

    International Nuclear Information System (INIS)

    Garibotti, C.R.; Grinstein, F.F.

    1977-01-01

    Approximants to functions defined by formal series expansions in orthogonal polynomials are introduced. They are shown to be convergent even out of the elliptical domain where the original expansion converges

  15. The epidural expansion in the waist canal - less obvious findings

    International Nuclear Information System (INIS)

    Nekula, J.; Bucil, J.; Burval, S.

    1998-01-01

    The authors demonstrated 55 less obvious epidural expansion in the waist canal. These expansions are discussed. The detection of the epidural mass at myeloma multiples has a principal significance for the indication of the radiotherapy or surgical intervention

  16. Dynamics of plasma expansion in the pulsed laser material interaction

    Indian Academy of Sciences (India)

    at different ambient gas pressures using an adiabatic expansion model. ... Pulsed laser; plasma expansion; plasma ionization; plume dimension. 1. ...... De A, Shakhatov V A, Pascale De O 2001 Optical emission spectroscopy and modeling of.

  17. Expansions for model-independent analyses of inelastic electron scattering

    International Nuclear Information System (INIS)

    Jackson, D.F.; Hilton, J.M.; Roberts, A.C.M.

    1977-01-01

    It is noted that the commonly-used Fourier-Bessel expansion for the transition density for inelastic electron scattering depends sensitively on an arbitrary parameter and is not realistic at large distances. Alternative expansions are suggested. (author)

  18. Lessons from Early Medicaid Expansions Under Health Reform..

    Data.gov (United States)

    U.S. Department of Health & Human Services — Lessons from Early Medicaid Expansions Under Health Reform, Interviews with Medicaid Officials In a new study entitled Lessons from Early Medicaid Expansions Under...

  19. Preparation of Shrinkage Compensating Concrete with HCSA Expansive Agent

    Science.gov (United States)

    Li, Changcheng; Jia, Fujia

    2017-10-01

    Shrinkage compensating concrete (SCC) has become one of the best effective methods of preventing and reducing concrete cracking. SCC is prepared by HCSA high performance expansive agent for concrete which restrained expansion rate is optimized by 0.057%. Slump, compressive strength, restrained expansion rate and cracking resistance test were carried out on SCC. The results show that the initial slump of fresh SCC was about 220mm-230mm, while slump after 2 hours was 180mm-200mm. The restrained expansion rate of SCC increased with the mixing amount of expansive agent. After cured in water for 14 days, the restrained expansion rate of C35 and C40 SCC were 0.020%-0.032%. With the dosage of expansive agent increasing, restrained expansion rate of SCC increased, maximum compressive stress and cracking stress improved, cracking temperature fell, thus cracking resistance got effectively improvement.

  20. A Revisit of Query Expansion with Different Semantic Levels

    DEFF Research Database (Denmark)

    Zhang, Ce; Cui, Bin; Cong, Gao

    2009-01-01

    Query expansion has received extensive attention in information retrieval community. Although semantic based query expansion appears to be promising in improving retrieval performance, previous research has shown that it cannot consistently improve retrieval performance. It is a tricky problem to...

  1. Following Surgically Assisted Rapid Palatal Expansion, Do Tooth-Borne or Bone-Borne Appliances Provide More Skeletal Expansion and Dental Expansion?

    Science.gov (United States)

    Hamedi-Sangsari, Adrien; Chinipardaz, Zahra; Carrasco, Lee

    2017-10-01

    The aim of this study was to compare outcome measurements of skeletal and dental expansion with bone-borne (BB) versus tooth-borne (TB) appliances after surgically assisted rapid palatal expansion (SARPE). This study was performed to provide quantitative measurements that will help the oral surgeon and orthodontist in selecting the appliance with, on average, the greatest amount of skeletal expansion and the least amount of dental expansion. A computerized database search was performed using PubMed, EBSCO, Cochrane, Scopus, Web of Science, and Google Scholar on publications in reputable oral surgery and orthodontic journals. A systematic review and meta-analysis was completed with the predictor variable of expansion appliance (TB vs BB) and outcome measurement of expansion (in millimeters). Of 487 articles retrieved from the 6 databases, 5 articles were included, 4 with cone-beam computed tomographic (CBCT) data and 1 with non-CBCT 3-dimensional cast data. There was a significant difference in skeletal expansion (standardized mean difference [SMD], 0.92; 95% confidence interval [CI], 0.54-1.30; P appliances. However, there was no significant difference in dental expansion (SMD, 0.05; 95% CI, -0.24 to 0.34; P = .03). According to the literature, to achieve more effective skeletal expansion and minimize dental expansion after SARPE, a BB appliance should be favored. Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  2. Expansive cements for the manufacture of the concrete protective bandages

    Science.gov (United States)

    Yakymechko, Yaroslav; Voloshynets, Vladyslav

    2017-12-01

    One of the promising directions of the use of expansive cements is making the protective bandages for the maintenance of pipelines. Bandages expansive application of the compositions of the pipeline reinforce the damaged area and reduce stress due to compressive stress in the cylindrical area. Such requirements are best suited for expansive compositions obtained from portland cement and modified quicklime. The article presents the results of expansive cements based on quick lime in order to implement protective bandages pipelines.

  3. MULTIPLE ANT COLONY SYSTEM FOR A VRP WITH TIME WINDOWS AND SCHEDULED LOADING MÚLTIPLES SISTEMAS DE COLONIAS DE HORMIGAS PARA UN VRP CON VENTANAS DE TIEMPO Y PROGRAMACIÓN DE LA CARGA

    Directory of Open Access Journals (Sweden)

    Pablo Ortega

    2009-12-01

    Full Text Available The vehicle routing problem with time windows and scheduled loading [VRPTWSL] requires not only the design of routes with time windows and capacity constraints, but also a schedule of the departures of vehicles from the depot given a load time due to the limited resources available to load the demand in the vehicles. A mathematical formulation of the vehicle routing problem with time windows and scheduled loading is presented and a metaheuristics based on Multiple Ant Colony System is proposed and implemented where two ant colonies, each with a single objective function, are organized in a hierarchical way. A time update procedure is incorporated into the ant constructive procedure to update and schedule the departure of a vehicle from the depot when each ant moves to a new customer-node. Constraint programming is used to determine a feasible move to a new customer-node. As [VRPTWSL] incorporates the vehicle departure scheduling, the algorithm presented in this paper has a direct application to real problems, in this way [VRPTWSL] can be taken as an important advance for practical vehicle routing problems.El problema de rutas para vehículos con ventanas de tiempo y programación de la carga no solo requiere el diseño de las rutas que satisfagan las restricciones temporales y de capacidad de los vehículos sino que también la programación de las salidas de los vehículos desde un terminal dado un tiempo de carga debido a los recursos limitados disponibles para cargar las demandas de los clientes en los vehículos. No solo se presenta una formulación del problema de diseño de rutas para vehículos con ventanas de tiempo y programación de la carga, sino que también se propone e implementa una metaheurística basada en múltiples sistemas de colonias de hormigas, cada una con una sola función objetivo, organizadas de manera jerárquica. Se incorpora una forma de actualización de tiempo dentro del procedimiento constructivo para actualizar

  4. Rapid replacement of bridge deck expansion joints study - phase I.

    Science.gov (United States)

    2014-12-01

    Bridge deck expansion joints are used to allow for movement of the bridge deck due to thermal expansion, dynamics loading, and : other factors. More recently, expansion joints have also been utilized to prevent the passage of winter de-icing chemical...

  5. Dynamical effects in the Colomb expansion following nuclear fragmentation

    International Nuclear Information System (INIS)

    Chung, K.C.; Donangelo, R.J.; Schechter, H.

    1987-01-01

    The effects of the Colomb expansion on the fragment Kinetic energy spectrum for a fragmentating hot nuclear system is investigated. In particular, 12 C fragment spectra are calculated and compared with those predicted by the uniform expansion approximation. The results indicate that energy spectra of fragments are quite sensitive to the details of the Coulomb expansion treatment. (Author) [pt

  6. Fission gas retention and axial expansion of irradiated metallic fuel

    International Nuclear Information System (INIS)

    Fenske, G.R.; Emerson, J.E.; Savoie, F.E.; Johanson, E.W.

    1986-05-01

    Out-of-reactor experiments utilizing direct electrical heating and infrared heating techniques were performed on irradiated metallic fuel. The results indicate accelerated expansion can occur during thermal transients and that the accelerated expansion is driven by retained fission gases. The results also demonstrate gas retention and, hence, expansion behavior is a function of axial position within the pin

  7. 14 CFR 23.969 - Fuel tank expansion space.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fuel tank expansion space. 23.969 Section 23.969 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT....969 Fuel tank expansion space. Each fuel tank must have an expansion space of not less than two...

  8. Hadronic mass-relations from topological expansion and string model

    International Nuclear Information System (INIS)

    Kaidalov, A.B.

    1980-01-01

    Hadronic mass-relations from topological expansion and string model are derived. For this purpose the space- time picture of hadron interactions at high energies corresponding to planar diagrams of topological expansion is considered. Simple relations between intercepts and slopes of Regge trajectories based on the topological expansion and q anti q-string picture of hadrons are obtained [ru

  9. Global operator expansions in conformally invariant relativistic quantum field theory

    International Nuclear Information System (INIS)

    Schoer, B.; Swieca, J.A.; Voelkel, A.H.

    1974-01-01

    A global conformal operator expansions in the Minkowski region in several models and their formulation in the general theory is presented. Whereas the vacuum expansions are termwise manisfestly conformal invariant, the expansions away from the vacuum do not share this property

  10. Presa con revestimiento asfáltico

    Directory of Open Access Journals (Sweden)

    Proudfit, D. P.

    1960-07-01

    Full Text Available La presa denominada Montgomery se halla situada sobre el río South Platte River, a unos 8 km aguas arriba de la ciudad de Alma, del Estado de Colorado (EE. UU., y en la ladera oriental de la cordillera Continental Divide. El cuerpo o dique de esta presa está constituido por piedra, revestida con una capa de hormigón asfáltico en el paramento de contacto con el agua.

  11. Trastornos temporomandibulares en pacientes con maloclusiones

    Directory of Open Access Journals (Sweden)

    Luis Soto Cantero

    Full Text Available Introducción: existe una prevalencia de trastornos oclusales en gran medida relacionados con la presencia de disfunción temporomandibular. Objetivo: determinar el grado de disfunción temporomandibular según el Índice de Maglione en correspondencia con la prevalencia de maloclusiones en el área de salud del policlínico "Turcios Lima". Métodos: se realizó un estudio observacional descriptivo, de corte transversal, en la consulta de ortodoncia, de junio del 2008 a junio del 2009. De un universo constituido por los 280 pacientes que acudieron al servicio de ortodoncia en el período señalado con presencia de maloclusiones, se seleccionó una muestra de 84 pacientes por muestreo aleatorio simple, teniendo en cuenta los criterios de inclusión y exclusión realizados por criterios de expertos. Resultados: presentaban disfunción temporomandibular 74 pacientes y dentro de ellos 44 (52,4 % tenían disfunción grado II (Moderada. El 97 % de los pacientes con relación molar de clase II, presentaban disfunción temporomandibular. El 42,9 % de los pacientes con una maloclusión, presentaban disfunción grado I. El 60 % de los pacientes con dos maloclusiones presentaban disfunción grado II y el 66,7 % de los pacientes con tres maloclusiones, presentaban disfunción grado III. La mayor cantidad de pacientes tuvieron disfunción grado II (Moderada. Conclusiones: el mayor por ciento de los pacientes con disfunciones presentó una clase II molar y a medida que aumentó el número de maloclusiones aumentó también la severidad de la disfunción.

  12. Zirconium titanate: stability and thermal expansion; Titanato de circonio: estabilidad termodinamica y expansion termica

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Lopez, E.; Moreno, R.; Baudin, C.

    2011-07-01

    Zirconium titanate is a well known compound in the field of electro ceramics, although it has also been used in catalyst and sensors applications. The crystallographic thermal expansion anisotropy of this compound makes it a potential candidate as constituent of structural components. In general, to assure the structural integrity and microstructural homogeneity of a ceramic piece, relatively low cooling rates from the fabrication temperature are required. This requirement is essential for zirconium titanate because thermal expansion as well as phase distribution is affected by small variations in the composition and cooling rate. This work reviews the available data on the phase equilibrium relationships in the systems ZrO{sub 2}-TiO{sub 2} and ZrO{sub 2}-TiO{sub 2}-Y{sub 2}O{sub 3}. The main discrepancies as well as the possible origins of them are discussed. Additionally, the crystallographic thermal expansion data in the current literature are reviewed. (Author) 56 refs.

  13. Expansion control for cementation of incinerated ash

    International Nuclear Information System (INIS)

    Nakayama, T.; Suzuki, S.; Hanada, K.; Tomioka, O.; Sato, J.; Irisawa, K.; Kato, J.; Kawato, Y.; Meguro, Y.

    2015-01-01

    A method, in which incinerated ash is solidified with a cement material, has been developed to dispose of radioactive incinerated ash waste. A small amount of metallic Al, which was not oxidized in the incineration, existed in the ash. When such ash was mixed with a cement material and water, alkaline components in the ash and the cement were dissolved in the mixing water and then metallic Al reaction with the alkaline compounds resulted in generation of H 2 . Because the H 2 generation began immediately just after the mixing, H 2 bubbles pushed up the mixed grout material and an expanded solidified form was obtained. The expansion leads to lowering the strength of the solidified form and making harmful void. In this study, we tried to control H 2 generation from the reaction of metallic Al in the cementation by means of following two methods, one was a method to let metallic Al react prior to the cementation and the other was a method to add an expansion inhibitor that made an oxide film on the surface of metallic Al. In the pre-treatment, the ash was soaked in water in order to let metallic Al react with it, and then the ash with the immersion solution was dried at 105 Celsius degrees. The pre-treated ash was mixed with an ordinary portland cement and water. The inhibitor of lithium nitrite, sodium nitrite, phosphoric acid, or potassium dihydrogen phosphate was added at the mixing process. The solidified forms prepared using the pre-treated ash and lithium nitrite were not expanded. Phosphoric acid and sodium nitrite were effective for expansion control, but potassium dihydrogen phosphate did not work. (authors)

  14. Private randomness expansion with untrusted devices

    International Nuclear Information System (INIS)

    Colbeck, Roger; Kent, Adrian

    2011-01-01

    Randomness is an important resource for many applications, from gambling to secure communication. However, guaranteeing that the output from a candidate random source could not have been predicted by an outside party is a challenging task, and many supposedly random sources used today provide no such guarantee. Quantum solutions to this problem exist, for example a device which internally sends a photon through a beamsplitter and observes on which side it emerges, but, presently, such solutions require the user to trust the internal workings of the device. Here, we seek to go beyond this limitation by asking whether randomness can be generated using untrusted devices-even ones created by an adversarial agent-while providing a guarantee that no outside party (including the agent) can predict it. Since this is easily seen to be impossible unless the user has an initially private random string, the task we investigate here is private randomness expansion. We introduce a protocol for private randomness expansion with untrusted devices which is designed to take as input an initially private random string and produce as output a longer private random string. We point out that private randomness expansion protocols are generally vulnerable to attacks that can render the initial string partially insecure, even though that string is used only inside a secure laboratory; our protocol is designed to remove this previously unconsidered vulnerability by privacy amplification. We also discuss extensions of our protocol designed to generate an arbitrarily long random string from a finite initially private random string. The security of these protocols against the most general attacks is left as an open question.

  15. Seasonal hydroclimatic impacts of Sun Corridor expansion

    International Nuclear Information System (INIS)

    Georgescu, M; Mahalov, A; Moustaoui, M

    2012-01-01

    Conversion of natural to urban land forms imparts influence on local and regional hydroclimate via modification of the surface energy and water balance, and consideration of such effects due to rapidly expanding megapolitan areas is necessary in light of the growing global share of urban inhabitants. Based on a suite of ensemble-based, multi-year simulations using the Weather Research and Forecasting (WRF) model, we quantify seasonally varying hydroclimatic impacts of the most rapidly expanding megapolitan area in the US: Arizona’s Sun Corridor, centered upon the Greater Phoenix metropolitan area. Using a scenario-based urban expansion approach that accounts for the full range of Sun Corridor growth uncertainty through 2050, we show that built environment induced warming for the maximum development scenario is greatest during the summer season (regionally averaged warming over AZ exceeds 1 °C). Warming remains significant during the spring and fall seasons (regionally averaged warming over AZ approaches 0.9 °C during both seasons), and is least during the winter season (regionally averaged warming over AZ of 0.5 °C). Impacts from a minimum expansion scenario are reduced, with regionally averaged warming ranging between 0.1 and 0.3 °C for all seasons except winter, when no warming impacts are diagnosed. Integration of highly reflective cool roofs within the built environment, increasingly recognized as a cost-effective option intended to offset the warming influence of urban complexes, reduces urban-induced warming considerably. However, impacts on the hydrologic cycle are aggravated via enhanced evapotranspiration reduction, leading to a 4% total accumulated precipitation decrease relative to the non-adaptive maximum expansion scenario. Our results highlight potentially unintended consequences of this adaptation approach within rapidly expanding megapolitan areas, and emphasize the need for undeniably sustainable development paths that account for

  16. Private randomness expansion with untrusted devices

    Science.gov (United States)

    Colbeck, Roger; Kent, Adrian

    2011-03-01

    Randomness is an important resource for many applications, from gambling to secure communication. However, guaranteeing that the output from a candidate random source could not have been predicted by an outside party is a challenging task, and many supposedly random sources used today provide no such guarantee. Quantum solutions to this problem exist, for example a device which internally sends a photon through a beamsplitter and observes on which side it emerges, but, presently, such solutions require the user to trust the internal workings of the device. Here, we seek to go beyond this limitation by asking whether randomness can be generated using untrusted devices—even ones created by an adversarial agent—while providing a guarantee that no outside party (including the agent) can predict it. Since this is easily seen to be impossible unless the user has an initially private random string, the task we investigate here is private randomness expansion. We introduce a protocol for private randomness expansion with untrusted devices which is designed to take as input an initially private random string and produce as output a longer private random string. We point out that private randomness expansion protocols are generally vulnerable to attacks that can render the initial string partially insecure, even though that string is used only inside a secure laboratory; our protocol is designed to remove this previously unconsidered vulnerability by privacy amplification. We also discuss extensions of our protocol designed to generate an arbitrarily long random string from a finite initially private random string. The security of these protocols against the most general attacks is left as an open question.

  17. Private randomness expansion with untrusted devices

    Energy Technology Data Exchange (ETDEWEB)

    Colbeck, Roger; Kent, Adrian, E-mail: rcolbeck@perimeterinstitute.ca, E-mail: a.p.a.kent@damtp.cam.ac.uk [Perimeter Institute for Theoretical Physics, 31 Caroline Street North, Waterloo, ON N2L 2Y5 (Canada)

    2011-03-04

    Randomness is an important resource for many applications, from gambling to secure communication. However, guaranteeing that the output from a candidate random source could not have been predicted by an outside party is a challenging task, and many supposedly random sources used today provide no such guarantee. Quantum solutions to this problem exist, for example a device which internally sends a photon through a beamsplitter and observes on which side it emerges, but, presently, such solutions require the user to trust the internal workings of the device. Here, we seek to go beyond this limitation by asking whether randomness can be generated using untrusted devices-even ones created by an adversarial agent-while providing a guarantee that no outside party (including the agent) can predict it. Since this is easily seen to be impossible unless the user has an initially private random string, the task we investigate here is private randomness expansion. We introduce a protocol for private randomness expansion with untrusted devices which is designed to take as input an initially private random string and produce as output a longer private random string. We point out that private randomness expansion protocols are generally vulnerable to attacks that can render the initial string partially insecure, even though that string is used only inside a secure laboratory; our protocol is designed to remove this previously unconsidered vulnerability by privacy amplification. We also discuss extensions of our protocol designed to generate an arbitrarily long random string from a finite initially private random string. The security of these protocols against the most general attacks is left as an open question.

  18. RadCon: A Radiological Consequences Model

    International Nuclear Information System (INIS)

    Crawford, J.; Domel, R.U.

    2000-05-01

    RadCon estimates the dose received by user selected groups in the population from an accidental release of radionuclides to the environment. The exposure pathways considered are external exposure from the cloud and ground and internal exposure from inhalation and ingestion of contaminated food. Atmospheric dispersion modelling is carried out externally to RadCon.Given a two dimensional time varying air and ground concentration of radioactive elements, RadCon allows the user to: view the air and ground concentration over the affected area, select optional parameters and calculate the dose to people,display the results to the user, and change the parameter values. RadCon offers two user interfaces: 1) the standard graphical user interface which is started using Java DoseApp at the command line, or by setting up a shortcut to this command (particularly when RadCon is installed on a PC) and 2) the text based interface used to generate information for the model inter-comparison exercise . This is initiated using Java BIOMASS at the command line, or an equivalent shortcut. The text based interface was developed for research purposes and is not generally available. Appendices A, B and C provide a summary of instructions on setting up RadCon. This will generally be carried out by the computer support personnel

  19. Adolescente femenino con granulomatosis de Wegener fulminante

    Directory of Open Access Journals (Sweden)

    S C Scheffler-Mendoza

    2017-01-01

    Full Text Available Adolescente femenino de 13 años de edad, originaria de Guerrero, grupo étnico mixteco, padres analfabetos y con poco entendimiento del español. Sin otros antecedentes de importancia para el padecimiento. Inició un mes previo con la aparición de una pápula hipercrómica en párpado superior derecho que en los 10 días previos al ingreso aumentó de volumen generando proptosis. Al interrogatorio se negó dolor, lagrimeo, fiebre, o pérdida de peso. Ingresó con fiebre (39.0°C, palidez generalizada, proptosis derecha con exposición de córnea y conjuntiva, eritema periorbitario, movimientos oculares y agudeza visual disminuidos (i.e. contaba dedos a 1 m, pupila con tendencia a midriasis, hiperreactividad a la luz, y fondo de ojo con papila hiperémica edematosa y tortuosidad peripapilar. El resto de exploración no mostró datos relevantes. Se hospitalizó para iniciar tratamiento antimicrobiano parenteral de amplio espectro (i.e. ceftriaxona y vancomicina y abordar proptosis unilateral.

  20. Cosmic expansion from boson and fermion fields

    International Nuclear Information System (INIS)

    De Souza, Rudinei C; Kremer, Gilberto M

    2011-01-01

    This paper consists in analyzing an action that describes boson and fermion fields minimally coupled to the gravity and a common matter field. The self-interaction potentials of the fields are not chosen a priori but from the Noether symmetry approach. The Noether forms of the potentials allow the boson field to play the role of dark energy and matter and the fermion field to behave as standard matter. The constant of motion and the cyclic variable associated with the Noether symmetry allow the complete integration of the field equations, whose solution produces a universe with alternated periods of accelerated and decelerated expansion.

  1. Operator product expansion and its thermal average

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, S [Saha Inst. of Nuclear Physics, Calcutta (India)

    1998-05-01

    QCD sum rules at finite temperature, like the ones at zero temperature, require the coefficients of local operators, which arise in the short distance expansion of the thermal average of two-point functions of currents. We extend the configuration space method, applied earlier at zero temperature, to the case at finite temperature. We find that, upto dimension four, two new operators arise, in addition to the two appearing already in the vacuum correlation functions. It is argued that the new operators would contribute substantially to the sum rules, when the temperature is not too low. (orig.) 7 refs.

  2. Topological expansion of the chain of matrices

    International Nuclear Information System (INIS)

    Eynard, B.; Ferrer, A. Prats

    2009-01-01

    We solve the loop equations to all orders in 1/N 2 , for the Chain of Matrices matrix model (with possibly an external field coupled to the last matrix of the chain). We show that the topological expansion of the free energy, is, like for the 1 and 2-matrix model, given by the symplectic invariants of [19]. As a consequence, we find the double scaling limit explicitly, and we discuss modular properties, large N asymptotics. We also briefly discuss the limit of an infinite chain of matrices (matrix quantum mechanics).

  3. Derivative expansion and renormalisation group flows

    CERN Document Server

    Litim, Daniel F

    2001-01-01

    We study the convergence of the derivative expansion for flow equations. The convergence strongly depends on the choice for the infrared regularisation. Based on the structure of the flow, we explain why optimised regulators lead to better physical predictions. This is applied to O(N)-symmetric real scalar field theories in 3d, where critical exponents are computed for all N. In comparison to the sharp cut-off regulator, an optimised flow improves the leading order result up to 10%. An analogous reasoning is employed for a proper time renormalisation group. We compare our results with those obtained by other methods.

  4. The colour and flavour 1/N expansions

    International Nuclear Information System (INIS)

    Veneziano, G.

    General ideas about the colour and flavour 1/N expansions are presented in a non-specialized fashion according to both: a unified approach to meson dynamics (the basic logical scheme, lepton-hadron interactions, hadronic processes in lowest order, higher order effects and the Reggeon calculus); and a possible extension to baryons (difficulties with baryons in dual and gauge theories, possible definition of dual baryons in quantum chromodynamics, lowest order B anti-B and BB scattering: baryonium, Reggeon calculus for processes involving baryons)

  5. Exponential expansion: galactic destiny or technological hubris?

    Science.gov (United States)

    Finney, B. R.

    Is it our destiny to expand exponentially to populate the galaxy, or is such a vision but an extreme example of technological hubris? The overall record of human evolution and dispersion over the Earth can be cited to support the view that we are a uniquely expansionary and technological animal bound for the stars, yet an examination of the fate of individual migrations and exploratory initiatives raises doubts. Although it may be in keeping with our hubristic nature to predict ultimate galactic expansion, there is no way to specify how far expansionary urges may drive our spacefaring descendants.

  6. Kato expansion in quantum canonical perturbation theory

    Energy Technology Data Exchange (ETDEWEB)

    Nikolaev, Andrey, E-mail: Andrey.Nikolaev@rdtex.ru [Institute of Computing for Physics and Technology, Protvino, Moscow Region, Russia and RDTeX LTD, Moscow (Russian Federation)

    2016-06-15

    This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson’s ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders.

  7. Capacity Expansion Modeling for Storage Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Hale, Elaine; Stoll, Brady; Mai, Trieu

    2017-04-03

    The Resource Planning Model (RPM) is a capacity expansion model designed for regional power systems and high levels of renewable generation. Recent extensions capture value-stacking for storage technologies, including batteries and concentrating solar power with storage. After estimating per-unit capacity value and curtailment reduction potential, RPM co-optimizes investment decisions and reduced-form dispatch, accounting for planning reserves; energy value, including arbitrage and curtailment reduction; and three types of operating reserves. Multiple technology cost scenarios are analyzed to determine level of deployment in the Western Interconnection under various conditions.

  8. Kato expansion in quantum canonical perturbation theory

    International Nuclear Information System (INIS)

    Nikolaev, Andrey

    2016-01-01

    This work establishes a connection between canonical perturbation series in quantum mechanics and a Kato expansion for the resolvent of the Liouville superoperator. Our approach leads to an explicit expression for a generator of a block-diagonalizing Dyson’s ordered exponential in arbitrary perturbation order. Unitary intertwining of perturbed and unperturbed averaging superprojectors allows for a description of ambiguities in the generator and block-diagonalized Hamiltonian. We compare the efficiency of the corresponding computational algorithm with the efficiencies of the Van Vleck and Magnus methods for high perturbative orders.

  9. The Dynamics of Regional and Global Expansion

    DEFF Research Database (Denmark)

    Geisler Asmussen, Christian; Nielsen, Bo Bernhard; Osegowitsch, Tom

    2015-01-01

    Purpose – The purpose of this paper is to model and test the dynamics of home-regional and global penetration by multi-national enterprises (MNEs). Design/methodology/approach – Drawing on international business (IB) theory, the authors model MNEs adjusting their home-regional and global market...... domain. Findings – The authors demonstrate that MNEs do penetrate both home-regional and global markets, often simultaneously, and that penetration levels often oscillate within an MNE over time. The authors show firms’ rates of regional and global expansion to be affected by their existing regional...

  10. External momentum expansion in NJL model

    International Nuclear Information System (INIS)

    Huang Mei; Zhao Weiqin; Zhuang Pengfei

    1999-01-01

    In the large N c expansion beyond mean-field approximation, the authors develop a general scheme of SU(2) NJL model including current quark mass explicitly. In the scheme, the constituent quark's propagator is expanded in pions external momentum k, and all the Feynman diagrams are naturally expanded to k 2 term in a unified way. The numerical results show that in the mean field approximation, the effect of current quark mass is invisible, however, the effect of current quark mass can be seen explicitly beyond mean-field approximation for reasonable choices of the parameters in NJL model

  11. The replication of expansive production knowledge

    DEFF Research Database (Denmark)

    Wæhrens, Brian Vejrum; Yang, Cheng; Madsen, Erik Skov

    2012-01-01

    Purpose – With the aim to support offshore production line replication, this paper specifically aims to explore the use of templates and principles to transfer expansive productive knowledge embedded in a production line and understand the contingencies that influence the mix of these approaches......; and (2) rather than being viewed as alternative approaches, templates and principles should be seen as complementary once the transfer motive moves beyond pure replication. Research limitations – The concepts introduced in this paper were derived from two Danish cases. While acceptable for theory...

  12. Conformal Dimensions via Large Charge Expansion.

    Science.gov (United States)

    Banerjee, Debasish; Chandrasekharan, Shailesh; Orlando, Domenico

    2018-02-09

    We construct an efficient Monte Carlo algorithm that overcomes the severe signal-to-noise ratio problems and helps us to accurately compute the conformal dimensions of large-Q fields at the Wilson-Fisher fixed point in the O(2) universality class. Using it, we verify a recent proposal that conformal dimensions of strongly coupled conformal field theories with a global U(1) charge can be obtained via a series expansion in the inverse charge 1/Q. We find that the conformal dimensions of the lowest operator with a fixed charge Q are almost entirely determined by the first few terms in the series.

  13. RadConEd: A Graphical Data Editor for the Radiological Consequences Model, RadCon

    International Nuclear Information System (INIS)

    Crawford, J.; Domel, R.U.

    2000-05-01

    This document describes the application, RadConEd, which has been designed and implemented to enable users of the RadCon system to update these parameter files. The RadCon system is written in the Java programming language, and as such provides portability across computer platforms. The software described in this report was developed in line with the portability requirements of RadCon, thus providing a uniform user interface across computer platforms and bypassing the need of using system editors. In addition a number of data integrity measures were implemented

  14. Correlation expansion: a powerful alternative multiple scattering calculation method

    International Nuclear Information System (INIS)

    Zhao Haifeng; Wu Ziyu; Sebilleau, Didier

    2008-01-01

    We introduce a powerful alternative expansion method to perform multiple scattering calculations. In contrast to standard MS series expansion, where the scattering contributions are grouped in terms of scattering order and may diverge in the low energy region, this expansion, called correlation expansion, partitions the scattering process into contributions from different small atom groups and converges at all energies. It converges faster than MS series expansion when the latter is convergent. Furthermore, it takes less memory than the full MS method so it can be used in the near edge region without any divergence problem, even for large clusters. The correlation expansion framework we derive here is very general and can serve to calculate all the elements of the scattering path operator matrix. Photoelectron diffraction calculations in a cluster containing 23 atoms are presented to test the method and compare it to full MS and standard MS series expansion

  15. Basis for calculations in the topological expansion

    International Nuclear Information System (INIS)

    Levinson, M.A.

    1982-12-01

    Investigations aimed at putting the topological theory of particles on a more quantitative basis are described. First, the incorporation of spin into the topological structure is discussed and shown to successfully reproduce the observed lowest mass hadron spectrum. The absence of parity-doubled states represents a significant improvement over previous efforts in similar directions. This theory is applied to the lowest order calculation of elementary hadron coupling constant ratios. SU(6)/sub W/ symmetry is maintained and extended via the notions of topological supersymmetry and universality. Finally, efforts to discover a perturbative basis for the topological expansion are described. This has led to the formulation of off-shell Feynman-like rules which provide a calculational scheme for the strong interaction components of the topological expansion once the zero-entropy connected parts are known. These rules are shown to imply a topological asymptotic freedom. Even though the nonlinear zero-entropy problem cannot itself be treated perturbatively, plausible general assumptions about zero-entropy amplitudes allow immediate qualitative inferences concerning physical hadrons. In particular, scenarios for mass splittings beyond the supersymmetric level are described

  16. Extended Plefka expansion for stochastic dynamics

    International Nuclear Information System (INIS)

    Bravi, B; Sollich, P; Opper, M

    2016-01-01

    We propose an extension of the Plefka expansion, which is well known for the dynamics of discrete spins, to stochastic differential equations with continuous degrees of freedom and exhibiting generic nonlinearities. The scenario is sufficiently general to allow application to e.g. biochemical networks involved in metabolism and regulation. The main feature of our approach is to constrain in the Plefka expansion not just first moments akin to magnetizations, but also second moments, specifically two-time correlations and responses for each degree of freedom. The end result is an effective equation of motion for each single degree of freedom, where couplings to other variables appear as a self-coupling to the past (i.e. memory term) and a coloured noise. This constitutes a new mean field approximation that should become exact in the thermodynamic limit of a large network, for suitably long-ranged couplings. For the analytically tractable case of linear dynamics we establish this exactness explicitly by appeal to spectral methods of random matrix theory, for Gaussian couplings with arbitrary degree of symmetry. (paper)

  17. On the binary expansions of algebraic numbers

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, David H.; Borwein, Jonathan M.; Crandall, Richard E.; Pomerance, Carl

    2003-07-01

    Employing concepts from additive number theory, together with results on binary evaluations and partial series, we establish bounds on the density of 1's in the binary expansions of real algebraic numbers. A central result is that if a real y has algebraic degree D > 1, then the number {number_sign}(|y|, N) of 1-bits in the expansion of |y| through bit position N satisfies {number_sign}(|y|, N) > CN{sup 1/D} for a positive number C (depending on y) and sufficiently large N. This in itself establishes the transcendency of a class of reals {summation}{sub n{ge}0} 1/2{sup f(n)} where the integer-valued function f grows sufficiently fast; say, faster than any fixed power of n. By these methods we re-establish the transcendency of the Kempner--Mahler number {summation}{sub n{ge}0}1/2{sup 2{sup n}}, yet we can also handle numbers with a substantially denser occurrence of 1's. Though the number z = {summation}{sub n{ge}0}1/2{sup n{sup 2}} has too high a 1's density for application of our central result, we are able to invoke some rather intricate number-theoretical analysis and extended computations to reveal aspects of the binary structure of z{sup 2}.

  18. Optimal separable bases and series expansions

    International Nuclear Information System (INIS)

    Poirier, B.

    1997-01-01

    A method is proposed for the efficient calculation of the Green close-quote s functions and eigenstates for quantum systems of two or more dimensions. For a given Hamiltonian, the best possible separable approximation is obtained from the set of all Hilbert-space operators. It is shown that this determination itself, as well as the solution of the resultant approximation, is a problem of reduced dimensionality. Moreover, the approximate eigenstates constitute the optimal separable basis, in the sense of self-consistent field theory. The full solution is obtained from the approximation via iterative expansion. In the time-independent perturbation expansion for instance, all of the first-order energy corrections are zero. In the Green close-quote s function case, we have a distorted-wave Born series with optimized convergence properties. This series may converge even when the usual Born series diverges. Analytical results are presented for an application of the method to the two-dimensional shifted harmonic-oscillator system, in the course of which the quantum tanh 2 potential problem is solved exactly. The universal presence of bound states in the latter is shown to imply long-lived resonances in the former. In a comparison with other theoretical methods, we find that the reaction path Hamiltonian fails to predict such resonances. copyright 1997 The American Physical Society

  19. Is China ready for its nuclear expansion?

    International Nuclear Information System (INIS)

    Zhou, Yun; Rengifo, Christhian; Hinze, Jonathan; Chen, Peipei

    2011-01-01

    China's rapid pace of nuclear energy growth is unique, and its impact on the global nuclear market as both a customer and potential future supplier is already tremendous and will continue to expand. It is crucial to understand this energy policy development and its impact on various global areas. Unfortunately, there is relatively limited English-language information available about China's nuclear power industry and its current development. This paper aims to provide a comprehensive assessment of the Chinese nuclear energy program and policy, reviewing its past, present, likely future developments, as well as to consider potential challenges that deserve further attention. This paper will explore reasons that have caused the existing industry, describe China's nuclear bureaucracy and decision making process to understand how different stakeholders play a role in China's nuclear energy development. This study concludes that China's existing nuclear program and industry, in combination with its current stable economic and political environment, provides a sound foundation for the planned nuclear expansion. However, challenges which are crucial to the success of the nuclear expansion will need to be addressed. (author)

  20. Operator expansion in σ-model

    International Nuclear Information System (INIS)

    Terent'ev, M.V.

    1986-01-01

    The operator expansion is studied in two dimensional σ-model with O(N) symmetry group at large values of N for the Green function at x 2 → 0 (Here n(x) is the dynamical field of σ-model). As a preliminary step the renormalization scheme is formulated in framework of I/N expansion where the intermediate scale μ 2 is introdused and regions of large (p > μ) and small (p 2 )/N in composite operators (here f(μ 2 ) is the effective coupling constant at the point μ 2 ) and the corrections of order of m 2 x 2 f(μ 2 )/N in the coefficient functions (here m is the dynamical mass-scale factor of σ-model) decisively depend on the recipe of factorization of small and large momenta regions. Due to the analogy between σ-model and quantum chromodynamics (QCD) the obtained result indicates the theoretical limitations to the accuracy of sum rule method in QCD

  1. Tensor integrand reduction via Laurent expansion

    Energy Technology Data Exchange (ETDEWEB)

    Hirschi, Valentin [SLAC, National Accelerator Laboratory,2575 Sand Hill Road, Menlo Park, CA 94025-7090 (United States); Peraro, Tiziano [Higgs Centre for Theoretical Physics, School of Physics and Astronomy,The University of Edinburgh,Edinburgh EH9 3JZ, Scotland (United Kingdom)

    2016-06-09

    We introduce a new method for the application of one-loop integrand reduction via the Laurent expansion algorithm, as implemented in the public C++ library Ninja. We show how the coefficients of the Laurent expansion can be computed by suitable contractions of the loop numerator tensor with cut-dependent projectors, making it possible to interface Ninja to any one-loop matrix element generator that can provide the components of this tensor. We implemented this technique in the Ninja library and interfaced it to MADLOOP, which is part of the public MADGRAPH5{sub A}MC@NLO framework. We performed a detailed performance study, comparing against other public reduction tools, namely CUTTOOLS, SAMURAI, IREGI, PJFRY++ and GOLEM95. We find that Ninja outperforms traditional integrand reduction in both speed and numerical stability, the latter being on par with that of the tensor integral reduction tool GOLEM95 which is however more limited and slower than Ninja. We considered many benchmark multi-scale processes of increasing complexity, involving QCD and electro-weak corrections as well as effective non-renormalizable couplings, showing that Ninja’s performance scales well with both the rank and multiplicity of the considered process.

  2. Notes on Mayer expansions and matrix models

    International Nuclear Information System (INIS)

    Bourgine, Jean-Emile

    2014-01-01

    Mayer cluster expansion is an important tool in statistical physics to evaluate grand canonical partition functions. It has recently been applied to the Nekrasov instanton partition function of N=2 4d gauge theories. The associated canonical model involves coupled integrations that take the form of a generalized matrix model. It can be studied with the standard techniques of matrix models, in particular collective field theory and loop equations. In the first part of these notes, we explain how the results of collective field theory can be derived from the cluster expansion. The equalities between free energies at first orders is explained by the discrete Laplace transform relating canonical and grand canonical models. In a second part, we study the canonical loop equations and associate them with similar relations on the grand canonical side. It leads to relate the multi-point densities, fundamental objects of the matrix model, to the generating functions of multi-rooted clusters. Finally, a method is proposed to derive loop equations directly on the grand canonical model

  3. Charge transfer reactions in Xe plasma expansion

    International Nuclear Information System (INIS)

    Jiao, C. Q.; Garscadden, A.; Ganguly, B. N.

    2007-01-01

    Charge transfer reactions of fast Xe ions with hydrocarbons including methane (CH 4 ), ethene (C 2 H 4 ), and propane (C 3 H 8 ) are studied by adding these hydrocarbon gases into a cross flowing Xe plasma expansion. Branching ratios and relative reaction rates for the charge transfers of fast Xe + with each of the three hydrocarbon gases are measured under different rf powers of the inductively coupled Xe discharge. For CH 4 /Xe system, we find that fast Xe + reacts readily with CH 4 generating CH 4 + and CH 3 + in a ratio of 1:0.56, with an estimated rate coefficient of (2.3±0.3)x10 -10 cm 3 /s at 75 W rf power which slowly increases to (2.9±0.3)x10 -10 cm 3 /s at 250 W (error bars reflect only the uncertainties due to the unknown extent of the ion recombination that follows the charge transfer reaction). These observed charge transfer reactions are made possible by the kinetically excited Xe ions produced by free expansion of the plasma. For the C 2 H 4 /Xe system product ions C 2 H 4 + and C 2 H 2 + are observed, and for C 3 H 8 /Xe, C 2 H 4 + and C 2 H 5 + and minor product ions including C 2 H 2 + and C 3 H 7 + are observed

  4. Rapid maxillary expansion in contemporary orthodontic literature

    Directory of Open Access Journals (Sweden)

    Sabrina Mutinelli

    2016-01-01

    Full Text Available We have reviewed our retrospective research about rapid maxillary expansion performed in the early mixed dentition to summarize the results of different studies regarding maxillary dental arch width variation and crowding improvement in light of contemporary literature. The aim is to define the effects of treatments followed until the end of dental arch growth. In all studies, a Haas expander anchored to the deciduous dentition was used. The samples consisted of treated patients with and without a lateral crossbite and homogeneous untreated individuals as controls. Two additional control groups of adolescents and adults in dental Class 1 were also compared. As a result of the analysis, rapid maxillary expansion with anchorage to the deciduous dentition was found to be effective in increasing transverse width in intermolar and intercanine areas, and the change was preserved until the full permanent dentition stage. When performed before maxillary lateral incisors have fully erupted, this procedure allows for a rapid increase in the arch length in the anterior area and consequently, in the space available for permanent incisors with a stable reduction in crowding over time.

  5. Extended Plefka expansion for stochastic dynamics

    Science.gov (United States)

    Bravi, B.; Sollich, P.; Opper, M.

    2016-05-01

    We propose an extension of the Plefka expansion, which is well known for the dynamics of discrete spins, to stochastic differential equations with continuous degrees of freedom and exhibiting generic nonlinearities. The scenario is sufficiently general to allow application to e.g. biochemical networks involved in metabolism and regulation. The main feature of our approach is to constrain in the Plefka expansion not just first moments akin to magnetizations, but also second moments, specifically two-time correlations and responses for each degree of freedom. The end result is an effective equation of motion for each single degree of freedom, where couplings to other variables appear as a self-coupling to the past (i.e. memory term) and a coloured noise. This constitutes a new mean field approximation that should become exact in the thermodynamic limit of a large network, for suitably long-ranged couplings. For the analytically tractable case of linear dynamics we establish this exactness explicitly by appeal to spectral methods of random matrix theory, for Gaussian couplings with arbitrary degree of symmetry.

  6. Application of the optimum reactive power dispatch to the cost establishment for the support voltage in a power electrical system for generalized dispatch; Aplicacion del despacho optimo de potencia reactiva al establecimiento del costo por el soporte de voltaje en un sistema electrico de potencia con despacho centralizado

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Gomez, Sergio Baruch

    2004-05-15

    de operacion. Por lo tanto existe la necesidad de determinar un costo por el soporte de voltaje de los generadores, ya que esta accion es considerada como un servicio auxiliar y es retribuida de manera independiente. En este trabajo, se utiliza el metodo del gradiente para solucionar el despacho de potencia reactiva y determinar el costo por el soporte de voltaje de cada generador participante en el sistema. El despacho de potencia reactiva esta sujeto a restricciones de igualdad que representan las ecuaciones de balance de potencia activa y reactiva de cada nodo y a restricciones de desigualdad que corresponden a los limites en los perfiles de voltaje de todos los nodos del sistema. Las restricciones de igualdad se consideran dentro del problema de optimizacion con el metodo de los multiplicadores de Lagrange y las restricciones de desigualdad a partir de funciones de penalizacion cuadraticas. El costo total por el soporte de voltaje de cada generador esta formado por un costo fijo y un costo variable. El costo fijo se calcula a partir del factor de recuperacion anual del capital invertido en el generador. El costo variable depende de las condiciones de operacion y del costo por perdida de oportunidad del generador. Para determinar el costo total por el soporte de voltaje de los generadores, se considera que el mercado de potencia activa ya ha sido resuelto con anterioridad a traves de un despacho economico de potencia activa. Los sistemas utilizados para la evaluacion del programa desarrollado son: el sistema de 5 nodos y el sistema de 30 nodos de la IEEE.

  7. Enfermedad coronaria en pacientes con psoriasis

    Directory of Open Access Journals (Sweden)

    Walter Masson

    2013-10-01

    Full Text Available Comunicaciones previas asociaron la psoriasis con la enfermedad coronaria. Desconocemos si en nuestro país o región existe dicha asociación. Se realizó un estudio transversal analizando los datos de la historia clínica electrónica de un sistema de salud de Buenos Aires. Analizamos todos los pacientes mayores de 18 años con diagnóstico de psoriasis entre el 1 de enero de 2003 y el 31 de julio de 2011 y los comparamos con un grupo control, en una relación 2:1, obtenido en forma aleatoria del mismo sistema de salud, apareados por edad y sexo. Determinamos la prevalencia de los factores de riesgo cardiovascular y de enfermedad coronaria. Analizamos la asociación entre la enfermedad coronaria y la psoriasis mediante análisis uni y multivariado. Se incluyeron 3 833 sujetos (1 286 pacientes con psoriasis y 2 547 controles. La prevalencia de hipertensión arterial (50% vs. 38%, p < 0.001, tabaquismo (25% vs. 17%, p < 0.001, diabetes (12% vs. 8%, p < 0.001 y enfermedad coronaria (4.98% vs. 3.06%, p = 0.003 fue mayor en los sujetos con psoriasis en comparación con el grupo control. Independientemente de la edad, la presencia de diabetes, hipertensión arterial o tabaquismo, hubo una asociación significativa entre la enfermedad coronaria y la psoriasis (OR 1.48, IC95% 1.04-2.11, p = 0.03. En conclusión, en esta población de Buenos Aires, los pacientes con psoriasis tuvieron una mayor prevalencia de diabetes, hipertensión arterial, tabaquismo y enfermedad coronaria. La asociación entre la psoriasis y la enfermedad coronaria fue independiente de los factores de riesgo explorados.

  8. Mincle Signaling Promotes Con-A Hepatitis

    Science.gov (United States)

    Greco, Stephanie H.; Torres-Hernandez, Alejandro; Kalabin, Aleksandr; Whiteman, Clint; Rokosh, Rae; Ravirala, Sushma; Ochi, Atsuo; Gutierrez, Johana; Salyana, Muhammad Atif; Mani, Vishnu R.; Nagaraj, Savitha V.; Deutsch, Michael; Seifert, Lena; Daley, Donnele; Barilla, Rocky; Hundeyin, Mautin; Nikifrov, Yuriy; Tejada, Karla; Gelb, Bruce E.; Katz, Steven C.; Miller, George

    2016-01-01

    Concanavalin-A (Con-A) hepatitis is regarded as a T cell-mediated model of acute liver injury. Mincle is a C-type lectin receptor (CLR) that is critical in the immune response to mycobacteria and fungi, but does not have a well-defined role in pre-clinical models of non-pathogen mediated inflammation. Since Mincle can ligate the cell death ligand SAP130, we postulated that Mincle signaling drives intrahepatic inflammation and liver injury in Con-A hepatitis. Acute liver injury was assessed in the murine Con-A hepatitis model using C57BL/6, Mincle−/−, and Dectin-1−/− mice. The role of C/EBPβ and HIF-1α signaling was assessed using selective inhibitors. We found that Mincle was highly expressed in hepatic innate inflammatory cells and endothelial cells in both mice and humans. Furthermore, sterile Mincle ligands and Mincle signaling intermediates were increased in the murine liver in Con-A hepatitis. Most significantly, Mincle deletion or blockade protected against Con-A hepatitis whereas Mincle ligation exacerbated disease. Bone marrow chimeric and adoptive transfer experiments suggested that Mincle signaling in infiltrating myeloid cells dictates disease phenotype. Conversely, signaling via other CLRs did not alter disease course. Mechanistically, we found that Mincle blockade decreased the NF-κβ related signaling intermediates, C/EBPβ and HIF-1α, both of which are necessary in macrophage-mediated inflammatory responses. Accordingly, Mincle deletion lowered production of nitrites in Con-A hepatitis and inhibition of both C/EBPβ and HIF1-α reduced the severity of liver disease. Our work implicates a novel innate immune driver of Con-A hepatitis and, more broadly, suggests a potential role for Mincle in diseases governed by sterile inflammation. PMID:27559045

  9. Mincle Signaling Promotes Con A Hepatitis.

    Science.gov (United States)

    Greco, Stephanie H; Torres-Hernandez, Alejandro; Kalabin, Aleksandr; Whiteman, Clint; Rokosh, Rae; Ravirala, Sushma; Ochi, Atsuo; Gutierrez, Johana; Salyana, Muhammad Atif; Mani, Vishnu R; Nagaraj, Savitha V; Deutsch, Michael; Seifert, Lena; Daley, Donnele; Barilla, Rocky; Hundeyin, Mautin; Nikifrov, Yuriy; Tejada, Karla; Gelb, Bruce E; Katz, Steven C; Miller, George

    2016-10-01

    Con A hepatitis is regarded as a T cell-mediated model of acute liver injury. Mincle is a C-type lectin receptor that is critical in the immune response to mycobacteria and fungi but does not have a well-defined role in preclinical models of non-pathogen-mediated inflammation. Because Mincle can ligate the cell death ligand SAP130, we postulated that Mincle signaling drives intrahepatic inflammation and liver injury in Con A hepatitis. Acute liver injury was assessed in the murine Con A hepatitis model using C57BL/6, Mincle(-/-), and Dectin-1(-/-) mice. The role of C/EBPβ and hypoxia-inducible factor-1α (HIF-1α) signaling was assessed using selective inhibitors. We found that Mincle was highly expressed in hepatic innate inflammatory cells and endothelial cells in both mice and humans. Furthermore, sterile Mincle ligands and Mincle signaling intermediates were increased in the murine liver in Con A hepatitis. Most significantly, Mincle deletion or blockade protected against Con A hepatitis, whereas Mincle ligation exacerbated disease. Bone marrow chimeric and adoptive transfer experiments suggested that Mincle signaling in infiltrating myeloid cells dictates disease phenotype. Conversely, signaling via other C-type lectin receptors did not alter disease course. Mechanistically, we found that Mincle blockade decreased the NF-κβ-related signaling intermediates C/EBPβ and HIF-1α, both of which are necessary in macrophage-mediated inflammatory responses. Accordingly, Mincle deletion lowered production of nitrites in Con A hepatitis and inhibition of both C/EBPβ and HIF-1α reduced the severity of liver disease. Our work implicates a novel innate immune driver of Con A hepatitis and, more broadly, suggests a potential role for Mincle in diseases governed by sterile inflammation. Copyright © 2016 by The American Association of Immunologists, Inc.

  10. Negative thermal expansion in functional materials: controllable thermal expansion by chemical modifications.

    Science.gov (United States)

    Chen, Jun; Hu, Lei; Deng, Jinxia; Xing, Xianran

    2015-06-07

    Negative thermal expansion (NTE) is an intriguing physical property of solids, which is a consequence of a complex interplay among the lattice, phonons, and electrons. Interestingly, a large number of NTE materials have been found in various types of functional materials. In the last two decades good progress has been achieved to discover new phenomena and mechanisms of NTE. In the present review article, NTE is reviewed in functional materials of ferroelectrics, magnetics, multiferroics, superconductors, temperature-induced electron configuration change and so on. Zero thermal expansion (ZTE) of functional materials is emphasized due to the importance for practical applications. The NTE functional materials present a general physical picture to reveal a strong coupling role between physical properties and NTE. There is a general nature of NTE for both ferroelectrics and magnetics, in which NTE is determined by either ferroelectric order or magnetic one. In NTE functional materials, a multi-way to control thermal expansion can be established through the coupling roles of ferroelectricity-NTE, magnetism-NTE, change of electron configuration-NTE, open-framework-NTE, and so on. Chemical modification has been proved to be an effective method to control thermal expansion. Finally, challenges and questions are discussed for the development of NTE materials. There remains a challenge to discover a "perfect" NTE material for each specific application for chemists. The future studies on NTE functional materials will definitely promote the development of NTE materials.

  11. Variables socionutricionales de hogares mazahuas integrados por preescolares desnutridos con madres con obesidad y sin obesidad

    Directory of Open Access Journals (Sweden)

    Conzuelo González, Viridiana Vanessa

    2009-01-01

    Full Text Available El primer objetivo fue conocer cuántos menores de cinco años con diferentes grados de desnutrición tienen una madre con sobrepeso/obesidad/ en una comunidad indígena que vive en extrema pobreza y bajo condiciones de migración masculina internacional. El segundo fue comparar tres variables socionutricionales (ingreso familiar, educación de la madre y adecuación nutrimental de la dieta diaria entre estos hogares y los hogares con desnutrición infantil y madres sin obesidad. Se realizó un estudio transversal (2006-2007, en la comunidad mazahua de San Francisco Tepeolulco, Municipio de Temascalcingo; que incluyó a 85 hogares integrados por preescolares con desnutrición inscritos al programa Oportunidades. Se determinó el estado nutrición de los preescolares con indicadores antropométricos y se obtuvo el IMC de las madres de estos infantes. Se aplicó una encuesta socionutricional, incluida el recordatorio de 24 horas, y complementado con la observación participante (cualitativa. Se encontró que 83% de las madres mazahuas presentaron sobrepeso u obesidad. El estado de nutrición de los preescolares con madres con obesidad presentó un porcentaje mayor de desnutrición (76%. En la variable género, se encontró que 54% de los niños con madres con obesidad tenía baja talla. Al relacionar el nivel educativo de la madre, esta variable resultó ser estadísticamente significativa (p=0.015, donde el analfabetismo está más relacionado con la desnutrición infantil que tienen madres de bajo y/o peso normal. La elevada prevalencia de hogares conformados con preescolares con desnutrición y madres con obesidad, es un síntoma más de la pobreza en zonas indígenas en México, con bajo índice de desarrollo humano.

  12. ENERGY GENERATION EXPANSION PLANNING MODEL CONSIDERING EMISSIONS CONSTRAINTS

    Directory of Open Access Journals (Sweden)

    DIEGO ADOLFO MEJIA GIRALDO

    2010-01-01

    Full Text Available El problema de expansión de la generación consiste en determinar el tipo de tecnología, dimensionamiento, ubicación y momento en el cual nuevas plantas de generación deben ser integradas al sistema, en un horizonte de planeamiento dado, para satisfacer la demanda de energía pronosticada. En los últimos años, debido a un creciente interés en asuntos medioambientales, varias metodologías para resolver el problema de expansión de la generación han incluido algún tipo de política medioambiental, típicamente basada en restricciones de emisiones. Este artículo presenta un modelo lineal en una versión dinámica para resolver el problema de planeamiento de expansión de la generación. La principal diferencia entre el modelo propuesto y la mayoría de los trabajos presentados en la literatura especializada es la forma en que la política medioambiental ha sido contemplada. Tal política incluye: i impuestos sobre las emisiones de CO2, ii una reducción anual de emisiones en todo el sistema y iii el retiro gradual de plantas de generación ineficientes. El modelo propuesto ha sido aplicado al caso de expansión de los Estados Unidos para encontrar el portafolio de energía más rentable y sostenible en los próximos 20 años, considerando 11 regiones y 10 tipos diferentes de tecnología.

  13. Epilepsia de la infancia con paroxismos occipitales

    Directory of Open Access Journals (Sweden)

    Albia Pozo Alonso

    1999-09-01

    Full Text Available Se reporta que la epilepsia de la infancia con paroxismos occipitales constituye un síndrome epiléptico muy bien definido; se incluye en el grupo de las epilepsias idiopáticas relacionadas con localización. Los ataques comienzan habitualmente con síntomas visuales, en ocasiones seguidos por ataques hemiclónicos, parciales complejos y tónicoclónicos generalizados. El electroencefalograma interictal muestra complejos de puntaonda de localización occipital y temporal posterior que desaparecen con la apertura de los ojos. Se presenta una paciente de 8 años de edad que reúne los criterios clínicos y electroencefalográficos de la epilepsia de la infancia con paroxismos occipitales y se enfatiza en la evolución supuestamente benigna de dicho síndrome.Is is reported that epilepsy of childhood with occipital paroxysms is an epileptic syndrome that is well defined. It is included in the group of related idiopathic epilepsies with localization. Seizures habitually begin with visual symptoms, which are ocassionally followed by hemiclonic, complex partial, and generalized tonicclonic seizures. The interictal EEG shows spike-wave complexes of occipital and temporal posterior localization that are suppressed by eye opening. A patient aged 8 in whom the clinical and electroencephalographic criteria of epilepsy of childhood with occipital paroxysms are present is studied in this paper. Emphasis is made on the apparently benign evolution of this syndrome.

  14. Separable expansion for realistic multichannel scattering problems

    International Nuclear Information System (INIS)

    Canton, L.; Cattapan, G.; Pisent, G.

    1987-01-01

    A new approach to the multichannel scattering problem with realistic local or nonlocal interactions is developed. By employing the negative-energy solutions of uncoupled Sturmian eigenvalue problems referring to simple auxiliary potentials, the coupling interactions appearing to the original multichannel problem are approximated by finite-rank potentials. By resorting to integral-equation tecniques the coupled-channel equations are then reduced to linear algebraic equations which can be straightforwardly solved. Compact algebraic expressions for the relevant scattering matrix elements are thus obtained. The convergence of the method is tasted in the single-channel case with realistic optical potentials. Excellent agreement is obtained with a few terms in the separable expansion for both real and absorptive interactions

  15. Current expansion of the Elliot Lake mines

    International Nuclear Information System (INIS)

    Stenning, G.

    1982-06-01

    The Elliot Lake mines are located in northern Ontario, on the north shore of Lake Huron. Mining operations in this area started in the mid-1950's and were curtailed during the 1960's. Starting in 1973 Rio Algom's Quirke mine and Denison, the only producers remaining in the area, started to make plans to expand. Increasing production to 30,000 tpd (milled) requires the reopening of the Panel and Stanleigh Mines of the Rio Algom group and the Stanrock-CanMet area at Denison. The first phase of the expansion was preceded by extensive public hearings. Mine production increases, improvement to the facilities at the reopened mines, and the effects on community facilities are described in this paper

  16. DISRUPTING SHOCKS IN POSTWAR GLOBAL ECONOMIC EXPANSION

    Directory of Open Access Journals (Sweden)

    Dumitru FILIPEANU

    2016-06-01

    Full Text Available The coherence of the global economic system, created by its upswing in the first postwar decades, started to crumble in the ’70s. The destabilizing shocks affected the entire world, but in an uneven manner, in different geographical areas and at different times, being felt most acutely, with devastating economic and social effects, in Third World countries. Although the developed countries were affected as well, they always had means to combat or to diminish the adverse effects of the crises, leading to "gentler" consequences. This paper focuses on four main aspects in postwar global economic expansion, namely: the ’70s – the international monetary crisis and the oil shocks; the foreign debt crisis; the Latin American debt crisis, the Asian financial crises and the current global crisis.

  17. The worldwide expansion of the Argentine ant

    DEFF Research Database (Denmark)

    Vogel, Valerie; Pedersen, Jes Søe; Giraud, Tatiana

    2010-01-01

    Aim The aim of this study was to determine the number of successful establishments of the invasive Argentine ant outside native range and to see whether introduced supercolonies have resulted from single or multiple introductions. We also compared the genetic diversity of native versus introduced...... supercolonies to assess the size of the propagules (i.e. the number of founding individuals) at the origin of the introduced supercolonies. Location Global. Methods We used mitochondrial DNA (mtDNA) markers and microsatellite loci to study 39 supercolonies of the Argentine ant Linepithema humile covering both......) and secondary introductions (from sites with established invasive supercolonies) were important in the global expansion of the Argentine ant. In combination with the similar social organization of colonies in the native and introduced range, this indicates that invasiveness did not evolve recently as a unique...

  18. Effects of forest expansion on mountain grassland

    DEFF Research Database (Denmark)

    Guidi, Claudia; Magid, Jakob; Rodeghiero, Mirco

    2014-01-01

    Background and aims. Grassland abandonment followed by forest succession is the dominant land-use change in the European Alps. We studied the impact of current forest expansion on mountain grassland on changes in physical soil organic carbon (SOC) fractions along a land-use and management gradient......, focusing on changes in aggregate stability and particulate organic matter (POM). Methods. Four successional stages were investigated: managed grassland, two transitional phases in which grassland abandonment led to colonization by Picea abies (L.) Karst., and old mixed forest dominated by Fagus sylvatica L....... Results. The dimension of aggregates assessed by aggregate size fractionation tended to increase, whereas SOC allocation to stable aggregates assessed by sizedensity fractionation decreased following conversion of grassland to forest (e.g. from 81 to 59 % in the 0–5 cm layer). The amount of SOC stored...

  19. Rarefied, superorbital flows in an expansion tube

    Energy Technology Data Exchange (ETDEWEB)

    Wheatley, V.; Chiu, H.S.; Jacobs, P.A.; Macrossan, M.N.; Mee, D.J.; Morgan, R.G.

    2004-04-01

    This paper describes a free-piston driven expansion tube and its instrumentation. The facility is used to generate rarefied flows at speeds of approximately 10 km/s. Although the flow in the tube itself is in the continuum regime, rarefied flow conditions are achieved by allowing the test gas to further expand as a free jet into the facility's test section. The test flow is surveyed to provide bar-gauge pressure measurements. Numerical simulation is then used to describe more fully the test flow properties. The flows produced are suitable for the aerodynamic testing of small models at superorbital speeds and should provide data that are suitable for the calibration of Direct Simulation Monte-Carlo codes. (author)

  20. Critical point anomalies include expansion shock waves

    Energy Technology Data Exchange (ETDEWEB)

    Nannan, N. R., E-mail: ryan.nannan@uvs.edu [Mechanical Engineering Discipline, Anton de Kom University of Suriname, Leysweg 86, PO Box 9212, Paramaribo, Suriname and Process and Energy Department, Delft University of Technology, Leeghwaterstraat 44, 2628 CA Delft (Netherlands); Guardone, A., E-mail: alberto.guardone@polimi.it [Department of Aerospace Science and Technology, Politecnico di Milano, Via La Masa 34, 20156 Milano (Italy); Colonna, P., E-mail: p.colonna@tudelft.nl [Propulsion and Power, Delft University of Technology, Kluyverweg 1, 2629 HS Delft (Netherlands)

    2014-02-15

    From first-principle fluid dynamics, complemented by a rigorous state equation accounting for critical anomalies, we discovered that expansion shock waves may occur in the vicinity of the liquid-vapor critical point in the two-phase region. Due to universality of near-critical thermodynamics, the result is valid for any common pure fluid in which molecular interactions are only short-range, namely, for so-called 3-dimensional Ising-like systems, and under the assumption of thermodynamic equilibrium. In addition to rarefaction shock waves, diverse non-classical effects are admissible, including composite compressive shock-fan-shock waves, due to the change of sign of the fundamental derivative of gasdynamics.

  1. Expansion into lattice harmonics in cubic symmetries

    Science.gov (United States)

    Kontrym-Sznajd, G.

    2018-05-01

    On the example of a few sets of sampling directions in the Brillouin zone, this work shows how important the choice of the cubic harmonics is on the quality of approximation of some quantities by a series of such harmonics. These studies led to the following questions: (1) In the case that for a given l there are several independent harmonics, can one use in the expansion only one harmonic with a given l?; (2) How should harmonics be ordered: according to l or, after writing them in terms of (x4 + y4 + z4)n (x2y2z2)m, according to their degree q = n + m? To enable practical applications of such harmonics, they are constructed in terms of the associated Legendre polynomials up to l = 26. It is shown that electron momentum densities, reconstructed from experimental data for ErGa3 and InGa3, are described much better by harmonics ordered with q.

  2. Breeding bird response to juniper woodland expansion

    Science.gov (United States)

    Rosenstock, Steven S.; van Riper, Charles

    2001-01-01

    In recent times, pinyon (Pinus spp.)-juniper (Juniperus spp.) woodlands have expanded into large portions of the Southwest historically occupied by grassland vegetation. From 1997-1998, we studied responses of breeding birds to one-seed juniper (J. monosperma) woodland expansion at 2 grassland study areas in northern Arizona. We sampled breeding birds in 3 successional stages along a grassland-woodland gradient: un-invaded grassland, grassland undergoing early stages of juniper establishment, and developing woodland. Species composition varied greatly among successional stages and was most different between endpoints of the gradient. Ground-nesting grassland species predominated in uninvaded grassland but declined dramatically as tree density increased. Tree- and cavity-nesting species increased with tree density and were most abundant in developing woodland. Restoration of juniper-invaded grasslands will benefit grassland-obligate birds and other wildlife.

  3. Population Genetics of Three Dimensional Range Expansions

    Science.gov (United States)

    Lavrentovich, Maxim; Nelson, David

    2014-03-01

    We develop a simple model of genetic diversity in growing spherical cell clusters, where the growth is confined to the cluster surface. This kind of growth occurs in cells growing in soft agar, and can also serve as a simple model of avascular tumors. Mutation-selection balance in these radial expansions is strongly influenced by scaling near a neutral, voter model critical point and by the inflating frontier. We develop a scaling theory to describe how the dynamics of mutation-selection balance is cut off by inflation. Genetic drift, i.e., local fluctuations in the genetic diversity, also plays an important role, and can lead to the extinction even of selectively advantageous strains. We calculate this extinction probability, taking into account the effect of rough population frontiers.

  4. Thermal linear expansion coefficient of structural graphites

    International Nuclear Information System (INIS)

    Virgil'ev, Yu.S.

    1995-01-01

    The data now available on radiation induced changes of linear thermal expansion coefficients (CTE) for native structural carbon materials (SCM) irradiated with high fluences are summarized. For different types of native and foreign SCM dose dependences of CTE changes in the temperature range of 300...1600 K and at fluences up to (2...3)x10 22 n/cm 2 (E>0.18 meV) are compared. On the base of this comparison factors defined the CTE changes under neutron irradiation are revealed and the explanation of observed phenomena is offered. Large number of the factors revealed does not allowed to calculate CTE radiation induced changes. 39 refs.; 16 figs.; 5 tabs

  5. A non-perturbative operator product expansion

    International Nuclear Information System (INIS)

    Bietenholz, W.; Cundy, N.; Goeckeler, M.

    2009-10-01

    Nucleon structure functions can be observed in Deep Inelastic Scattering experiments, but it is an outstanding challenge to confront them with fully non-perturbative QCD results. For this purpose we investigate the product of electromagnetic currents (with large photonmomenta) between quark states (of low momenta). By means of an Operator Product Expansion the structure function can be decomposed into matrix elements of local operators, and Wilson coefficients. For consistency both have to be computed non-perturbatively. Here we present precision results for a set of Wilson coefficients. They are evaluated from propagators for numerous quark momenta on the lattice, where the use of chiral fermions suppresses undesired operator mixing. This overdetermines the Wilson coefficients, but reliable results can be extracted by means of a Singular Value Decomposition. (orig.)

  6. Portugal's Petrogal eyes expansion amid continuing privatization

    International Nuclear Information System (INIS)

    Anon.

    1995-01-01

    Portugal's recently privatized state oil company Petrogal is about to embark on a major expansion worldwide. That comes against the backdrop of major change in Portugal's energy sector and the rocky road to Petrogal's partial privatization. Despite the controversy, there remain opportunities for foreign companies investing in Portugal's energy sector. The most attractive opportunities are in Portugal's downstream petroleum sector and in the country's continuing campaign to develop its natural gas industry. Typical of the latter is Portugal's participation in the Trans-Maghreb gas pipeline megaproject. The paper discusses the background to privatization, its current status, Petrogal strategy, modernization of refineries, a joint partnership with Venezuela, constraints, energy policy program, gas pipeline privatization, and concerns of the gas industry

  7. Sectoral and regional expansion of emissions trading

    Energy Technology Data Exchange (ETDEWEB)

    Boehringer, Christoph; Bouwe, Dijkstra; Rosendahl, Knut Einar

    2011-07-01

    We consider an international emissions trading scheme with partial sectoral and regional coverage. Sectoral and regional expansion of the trading scheme is beneficial in aggregate, but not necessarily for individual countries. We simulate international CO{sub 2} emission quota markets using marginal abatement cost functions and the Copenhagen 2020 climate policy targets for selected countries that strategically allocate emissions in a bid to manipulate the quota price. Quota exporters and importers generally have conflicting interests about admitting more countries to the trading coalition, and our results indicate that some countries may lose substantially when the coalition expands in terms of new countries. For a given coalition, expanding sectoral coverage makes most countries better off, but some countries (notably the USA and Russia) may lose out due to loss of strategic advantages. In general, exporters tend to have stronger strategic power than importers.(Author)

  8. Behaviour of built light construction on expansible clays. Technical of design and rehabilitation

    Directory of Open Access Journals (Sweden)

    Arrieta, L.

    2003-12-01

    Full Text Available The construction pathology of housing built on expansible clays is one of the most requested topics to be investigated in order to obtain solutions mainly in housing of social interest. A vision of the solution alternatives is presented that are being applying in Venezuela and specifically in the cities of Barquisimeto and Coro where the most harmful expansion characteristics are presented registered in the world literature. This population is located to the north of the country in front of the Caribbean Sea with arid climate, deep phreatic level, appreciable loamy profile and water deficit. The investigation methodology and some proven procedures for the design of foundations in light housings and for the rehabilitation of damaged buildings are supported with the results of the researches on the part of the two authors and their research teams coming from two different Universities and with 20 years of experience in the practical field. 3 cases are illustrated, two of them with historical value in the design of housings of social interest and one of severely affected constructions and actually rehabilitated with success. Finally some practical recommendations are provided to be considered in the elaboration of projects related with the construction of light housings on expansible floors.

    La patología de construcción de viviendas construidas sobre arcillas expansivas constituye uno de los temas más investigados debido a la gran cantidad de casos identificados con fallos, sobre todo en viviendas de interés social. Se presenta una visión de las alternativas de solución que se vienen aplicando en Venezuela y, específicamente, en las ciudades de Barquisimeto y Coro donde se presentan las características de expansión más perjudiciales registradas en la literatura mundial. Esta población está ubicada al norte del país, frente al mar Caribe, con clima árido, nivel freático profundo, perfil arcilloso apreciable y régimen h

  9. Expansive focal cemento-osseous dysplasia.

    Science.gov (United States)

    Bulut, Emel Uzun; Acikgoz, Aydan; Ozan, Bora; Zengin, Ayse Zeynep; Gunhan, Omer

    2012-01-01

    To present a case of expansive focal cemento-osseous dysplasia and emphasize the importance of differential diagnosis. Cemento-osseous dysplasia is categorized into three subtypes on the basis of the clinical and radiographic features: Periapical, focal and florid. The focal type exhibits a single site of involvement in any tooth-bearing or edentulous area of the jaws. These lesions are usually asymptomatic; therefore, they are frequently diagnosed incidentally during routine radiographic examinations. Lesions are usually benign, show limited growth, and do not require further surgical intervention, but periodic follow-up is recommended because occasionally, this type of dysplasia progresses into florid osseous dysplasia and simple bone cysts are formed. A 24-year-old female patient was referred to our clinic for swelling in the left edentulous mandibular premolarmolar region and felt discomfort when she wore her prosthetics. She had no pain, tenderness or paresthesia. Clinical examination showed that the swelling in the posterior mandible that was firm, nonfluctuant and covered by normal mucosa. On panoramic radiography and computed tomography, a well defined lesion of approximately 1.5 cm in diameter of mixed density was observed. The swelling increased slightly in size over 2 years making it difficult to use prosthetics and, therefore, the lesion was totally excised under local anesthesia, and surgical specimens were submitted for histopathological examination. The histopathological diagnosis was focal cemento-osseous dysplasia. In the present case, because of the increasing size of the swelling making it difficult to use prosthetics, young age of the patient and localization of the lesion, in the initial examination, cemento-ossifying fibroma was suspected, and the lesion was excised surgically; the histopathological diagnosis confirmed it as focal cemento-osseous dysplasia. We present a case of expansive focal cemento-osseous dysplasia. Differential diagnosis

  10. Thermal expansion studies on zircaloy-2

    International Nuclear Information System (INIS)

    Sivabharathy, M.; Senthilkumar, A.; Palanichamy, P.; Ramachandran, K.

    2016-01-01

    Zircaloy-2 and Zr-2.5% Nb alloys are widely used in the pressurized heavy water reactors (PHWR) as the material for the pressure tubes. The pressure tube operates at 573 K, 11 MPa internal pressures and is subjected to neutron flux of the order of 1013 n/cm 2 /s. These conditions lead to degradations in the pressure tube with respect to dimensional changes, deterioration in mechanical properties due to irradiation embrittlement, thereby reducing its flaw tolerance, the growth of existing flaws, which were too small or 'insignificant' at the time of installation. Physical and chemical properties of materials are also very essential in nuclear industry and the relations among them is of interest in the selection of materials when they are used in the design and manufacturing of devices particularly for atomic reactors.Studies on the relations between mechanical and thermal properties are of interest to the steel and metal industries as these would give useful information on the relation between hardness and thermal diffusivity (α) of steel. Jayakumar et al have already carried out the ultrasonic and metallographic investigations to see that all the heat-treated specimens retained essentially the martensite structure. In this present work, thermal expansion measurements on useful reactor material, Zircaloy-2 with different sample. Given a β-quenching treatment by heating to 1223 K and holding for 2 h, followed by water quenching. These specimens were then thermally aged for 1 h in the temperature range 473 to 973 K and air-cooled. For all samples, the thermal expansion was carried out and the results are correlated with ultrasonic measurements, metallographic and photoacoustic studies. (author)

  11. Expansion of an ultracold Rydberg plasma

    Science.gov (United States)

    Forest, Gabriel T.; Li, Yin; Ward, Edwin D.; Goodsell, Anne L.; Tate, Duncan A.

    2018-04-01

    We report a systematic experimental and numerical study of the expansion of ultracold Rydberg plasmas. Specifically, we have measured the asymptotic expansion velocities, v0, of ultracold neutral plasmas (UNPs) which evolve from cold, dense samples of Rydberg rubidium atoms using ion time-of-flight spectroscopy. From this, we have obtained values for the effective initial plasma electron temperature, Te ,0=mionv02/kB (where mion is the Rb+ ion mass), as a function of the original Rydberg atom density and binding energy, Eb ,i. We have also simulated numerically the interaction of UNPs with a large reservoir of Rydberg atoms to obtain data to compare with our experimental results. We find that for Rydberg atom densities in the range 107-109 cm-3, for states with principal quantum number n >40 , Te ,0 is insensitive to the initial ionization mechanism which seeds the plasma. In addition, the quantity kBTe ,0 is strongly correlated with the fraction of atoms which ionize, and is in the range 0.6 ×| Eb ,i|≲ kBTe ,0≲2.5 ×|Eb ,i| . On the other hand, plasmas from Rydberg samples with n ≲40 evolve with no significant additional ionization of the remaining atoms once a threshold number of ions has been established. The dominant interaction between the plasma electrons and the Rydberg atoms is one in which the atoms are deexcited, a heating process for electrons that competes with adiabatic cooling to establish an equilibrium where Te ,0 is determined by their Coulomb coupling parameter, Γe˜0.01 .

  12. Aspectos Psicosociales Relacionados con el TEPT en Pacientes con Cáncer de Mama

    OpenAIRE

    Hernández Moreno, Fresia Paloma; Landero Hernández, René

    2015-01-01

    El objetivo del estudio fue analizar la relación del estrés, la depresión y las estrategias de afrontamiento con el Trastorno de Estrés Postraumático (TEPT) en una muestra de pacientes con cáncer de mama. Se realizó con una muestra no probabilística de 52 mujeres con cáncer de mama. Se encontró una relación entre TEPT y estrés (r= .344, p= .014), TEPT y depresión (rs=.346, p= .013). El TEPT correlacionó con evitación cognitiva (r= .437, p= .001), TEPT y desesperanza (rs= .437, p= .001) y TEPT...

  13. Desarrollo de aleaciones multifuncionales con base titanio

    OpenAIRE

    Pareja, Ramiro

    2007-01-01

    El Laboratorio de Materiales Nano-estructurados y Multifuncionales del Departamento de Física de la Universidad Carlos III de Madrid se dedica al desarrollo, procesado y caracterización de aleaciones con propiedades mejores que las preparadas por métodos convencionales. La mejora de las propiedades se consigue produciendo las aleaciones con un tamaño de grano nanométrico o ultrafino, o introduciendo una dispersión de nano-partículas de óxido en la matriz. El grupo está interesado en algún tip...

  14. TIROTOXICOSIS GESTACIONAL: PATOLOGIA CON RIESGO VITAL

    OpenAIRE

    Valdés R.,Enrique; Pilasi M.,Carlos; Núñez U.,Tatiana

    2003-01-01

    Se presenta un caso clínico con diagnóstico final de Tirotoxicosis gestacional que debuta con una complicación excepcional, insuficiencia cardíaca congestiva e hipertensión pulmonar severa. Se presenta la experiencia del Hospital Clínico de la Universidad de Chile, proponiendo que su diagnóstico y tratamiento oportunos son la base del pronóstico de esta patología de riesgo vital para el binomio madre-hijo

  15. Amplificadores con transistores. Estudio y dimensionado

    OpenAIRE

    Lubiano García, Adrián

    2017-01-01

    Este trabajo es un estudio de las distintas configuraciones de los amplificadores con transistores vistos en la asignatura de Electrónica Analógica del tercer curso del Grado en Ingeniería en Electrónica Industrial y Automática de la Escuela de Ingenierías Industriales de la Universidad de Valladolid. En este trabajo se mostrarán los pasos seguidos en la creación de una aplicación con Visual Basic para la realización de los ejercicios de las distintas configuraciones, así...

  16. Galaxias australes con núcleo doble

    Science.gov (United States)

    Gimeno, G.; Díaz, R.; Carranza, G.

    Se estudia una muestra de galaxias australes con núcleo doble a partir de una búsqueda extensiva en la literatura. Se analizan las características morfológicas, fotométricas y espectroscópicas de la muestra. Para algunas galaxias se han realizado observaciones con el espectrógrafo multifunción (EMF) de la Estación Astrofísica de Bosque Alegre a partir de las cuales se determinaron parámetros cinemáticos.

  17. Research progress on expansive soil cracks under changing environment.

    Science.gov (United States)

    Shi, Bei-xiao; Zheng, Cheng-feng; Wu, Jin-kun

    2014-01-01

    Engineering problems shunned previously rise to the surface gradually with the activities of reforming the natural world in depth, the problem of expansive soil crack under the changing environment becoming a control factor of expansive soil slope stability. The problem of expansive soil crack has gradually become a research hotspot, elaborates the occurrence and development of cracks from the basic properties of expansive soil, and points out the role of controlling the crack of expansive soil strength. We summarize the existing research methods and results of expansive soil crack characteristics. Improving crack measurement and calculation method and researching the crack depth measurement, statistical analysis method, crack depth and surface feature relationship will be the future direction.

  18. Controlling Thermal Expansion: A Metal?Organic Frameworks Route

    OpenAIRE

    Balestra, Salvador R. G.; Bueno-Perez, Rocio; Hamad, Said; Dubbeldam, David; Ruiz-Salvador, A. Rabdel; Calero, Sofia

    2016-01-01

    Controlling thermal expansion is an important, not yet resolved, and challenging problem in materials research. A conceptual design is introduced here, for the first time, for the use of metal?organic frameworks (MOFs) as platforms for controlling thermal expansion devices that can operate in the negative, zero, and positive expansion regimes. A detailed computer simulation study, based on molecular dynamics, is presented to support the targeted application. MOF-5 has been selected as model m...

  19. Negative thermal expansion of lithium aluminosilicate ceramics at cryogenic temperatures

    International Nuclear Information System (INIS)

    Garcia-Moreno, Olga; Fernandez, Adolfo; Khainakov, Sergei; Torrecillas, Ramon

    2010-01-01

    Five lithium aluminosilicate compositions of the LAS system have been synthesized and sintered. The coefficient of thermal expansion of the sintered samples has been studied down to cryogenic conditions. The data presented here under cryogenic conditions will be of value in the future design of new composite materials with very low thermal expansion values. The variation in thermal expansion properties with composition and sintering temperature was studied and is discussed in relation to composition and crystal structure.

  20. Modeling of Viscosity and Thermal Expansion of Bioactive Glasses

    OpenAIRE

    Farid, Saad B. H.

    2012-01-01

    The behaviors of viscosity and thermal expansion for different compositions of bioactive glasses have been studied. The effect of phosphorous pentoxide as a second glass former in addition to silica was investigated. Consequently, the nonlinear behaviors of viscosity and thermal expansion with respect to the oxide composition have been modeled. The modeling uses published data on bioactive glass compositions with viscosity and thermal expansion. -regression optimization technique has been uti...

  1. Thermal and Hygric Expansion of High Performance Concrete

    OpenAIRE

    J. Toman; R. Černý

    2001-01-01

    The linear thermal expansion coefficient of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C, and the linear hygric expansion coefficient was determined in the moisture range from dry material to saturation water content. Comparative methods were applied for measurements of both coefficients. The experimental results show that both the effect of temperature on the values of linear thermal expansion coefficients and the effect of moisture on th...

  2. Does query expansion limit our learning? A comparison of social-based expansion to content-based expansion for medical queries on the internet.

    Science.gov (United States)

    Pentoney, Christopher; Harwell, Jeff; Leroy, Gondy

    2014-01-01

    Searching for medical information online is a common activity. While it has been shown that forming good queries is difficult, Google's query suggestion tool, a type of query expansion, aims to facilitate query formation. However, it is unknown how this expansion, which is based on what others searched for, affects the information gathering of the online community. To measure the impact of social-based query expansion, this study compared it with content-based expansion, i.e., what is really in the text. We used 138,906 medical queries from the AOL User Session Collection and expanded them using Google's Autocomplete method (social-based) and the content of the Google Web Corpus (content-based). We evaluated the specificity and ambiguity of the expansion terms for trigram queries. We also looked at the impact on the actual results using domain diversity and expansion edit distance. Results showed that the social-based method provided more precise expansion terms as well as terms that were less ambiguous. Expanded queries do not differ significantly in diversity when expanded using the social-based method (6.72 different domains returned in the first ten results, on average) vs. content-based method (6.73 different domains, on average).

  3. Studying medium effects with the optimized δ expansion

    International Nuclear Information System (INIS)

    Krein, G.; Menezes, D.P.; Nielsen, M.; Pinto, M.B.

    1995-04-01

    The possibility of using the optimized δ expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The δ expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu-Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model for the equation of state of nuclear matter. The results obtained with the δ expansion are compared to those obtained with the traditional Hartree-Fock approximation. Perspectives for using the δ expansion in other field theoretic models in hadron and nuclear physics are discussed. (author). 17 refs, 9 figs

  4. Studying medium effects with the optimized {delta} expansion

    Energy Technology Data Exchange (ETDEWEB)

    Krein, G [Instituto de Fisica Teorica (IFT), Sao Paulo, SP (Brazil); Menezes, D P [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Fisica; Nielsen, M [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Pinto, M B [Montpellier-2 Univ., 34 (France). Lab. de Physique Mathematique

    1995-04-01

    The possibility of using the optimized {delta} expansion for studying medium effects on hadronic properties in quark or nuclear matter is investigated. The {delta} expansion is employed to study density effects with two commonly used models in hadron and nuclear physics, the Nambu-Jona-Lasinio model for the dynamical chiral symmetry breaking and the Walecka model for the equation of state of nuclear matter. The results obtained with the {delta} expansion are compared to those obtained with the traditional Hartree-Fock approximation. Perspectives for using the {delta} expansion in other field theoretic models in hadron and nuclear physics are discussed. (author). 17 refs, 9 figs.

  5. Thermal and Hygric Expansion of High Performance Concrete

    Directory of Open Access Journals (Sweden)

    J. Toman

    2001-01-01

    Full Text Available The linear thermal expansion coefficient of two types of high performance concrete was measured in the temperature range from 20 °C to 1000 °C, and the linear hygric expansion coefficient was determined in the moisture range from dry material to saturation water content. Comparative methods were applied for measurements of both coefficients. The experimental results show that both the effect of temperature on the values of linear thermal expansion coefficients and the effect of moisture on the values of linear hygric expansion coefficients are very significant and cannot be neglected in practical applications.

  6. Operator expansion in quantum chromodynamics beyond perturbation theory

    International Nuclear Information System (INIS)

    Novikov, V.A.; Shifman, M.A.; Vainshtejn, A.I.; Zakharov, V.I.

    1980-01-01

    The status of operator expansion at short distances is descussed within the frameworks of nonperturbatue QCD. The question of instanton effects is investigated in various aspects. Two-point functions induced by the gluonic currents are considered. It is shown that certain gluonic correlations vanish in the field of definite duality. It is proved that there does exist a very special relation between the expansion coefficients required by consistancy between instanton calculations and the general operator expansion. At last a certain modification of the naive version of operator expansion is proposed, which allows one to go beyond the critical power and construct, if necessary, an infinite series

  7. Expansion of Tubular with Elastomers in Multilateral Wells

    Directory of Open Access Journals (Sweden)

    Md Velden

    2013-06-01

    Full Text Available The use of solid expandable tubular technology during the last decade has focused on solving many challenges in well drilling and delivery including zonal isolation, deep drilling, conservation of hole sizes, etc. not only as pioneered solution but also providing cost effective and long lasting solutions. Concurrently, the technology was extended for construction of multilateral in typical wells. The process of horizontal tubular expansion is similar to the vertical expansion of expandable tubular in down-hole environment with the addition of uniformly distributed force due to its weight. The expansion is targeted to increase its diameter such that post expansion characteristics remain within allowable limits. In this study a typical expandable tubular of 57.15 mm outer diameter and 6.35 mm wall thickness was used with two different elastomer seals of 5 and 7 mm thickness placed at equal spacing of 200 mm. The developed stress contours during expansion process clearly showed the high stress areas in the vicinity of expansion region which lies around the mandrel. These high stresses may result in excessive wear of the mandrel. It was also found out that the drawing force increases as the mandrel angle, expansion ratio, and friction coefficient increases. A mandrel angle of 20o  requires minimum expansion force and can be considered as an optimum geometrical parameter to lower the power required for expansion.

  8. Eigenfunction expansions and scattering theory in rigged Hilbert spaces

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Cubillo, F [Dpt. de Analisis Matematico, Universidad de Valladolid. Facultad de Ciencias, 47011 Valladolid (Spain)], E-mail: fgcubill@am.uva.es

    2008-08-15

    The work reviews some mathematical aspects of spectral properties, eigenfunction expansions and scattering theory in rigged Hilbert spaces, laying emphasis on Lippmann-Schwinger equations and Schroedinger operators.

  9. Mechanism of actuation in conducting polymers: Osmotic expansion

    DEFF Research Database (Denmark)

    Bay, Lasse; Jacobsen, Torben; West, Keld

    2001-01-01

    Conducting polymers expand or contract when their redox state is changed. This expansion/contraction effect can be separated in an intrinsic part because of changes of the polymer backbone on reduction/oxidation and a part depending on the surrounding electrolyte phase, because of osmotic expansion...... is compared with measurements on PPy(DBS) films. The experiments show that the expansion decreases as the electrolyte concentration is increased. This means that a considerable part of the total expansion is due to the osmotic effect. The osmotic effect should be taken into account when interpreting...

  10. Expansion And International Expansion Of Small-To Medium Sized Firms: The Role Of Finance

    OpenAIRE

    Jan Smolarski; Can Kut; Neil Wilner

    2011-01-01

    Small- to medium-sized firms are expected to show international growth at an early stage. Several factors may affect the outcome of initial efforts to expand and internationalize. Our research examines how equity based venture funding affects SME expansion and internationalization. We divide venture capital financing into two categories: incremental financing where firms receive their venture capital funding in portions and lump-sum venture funding where firms receive their funding in one lum...

  11. IoT con Raspberry Pi

    OpenAIRE

    García Muelas, Carlos

    2015-01-01

    Estudio de diferentes plataformas software y hardware del internet de las cosas. Aplicación real con Raspberry Pi. Estudi de diferents plataformes programari i maquinari de l'internet de les coses. Aplicació real amb Raspberry Pi. Bachelor thesis for the Telecommunication Technologies program on Telematics.

  12. en personas con el VIH/SIDA

    Directory of Open Access Journals (Sweden)

    Ximena Palacios Espinosa

    2006-01-01

    Full Text Available El objetivo de este estudio fue hallar la relación de la intención e ideación suicida con algunas variables sociodemográficas, las características de la enfermedad, el tratamiento antirretroviral y los aspectos piscoafectivos en personas con el VIH/SIDA que residen en Bogotá (Colombia y pertenecientes a una fundación. Para ello, se tomó una muestra de 75 pacientes con VIH positivo a quienes se evaluó a través de una entrevista semiestructurada y dos instrumentos: el inventario de depresión de Beck (IBD y la escala de Ideación Suicida (SSI. Los resultados mostraron que solo 29 personas tenían ideación suicida y 10 intención suicida: De los 10 solo 2 sujetos tenían intención después del diagnóstico. Se encontró una relación estadística significativa para ideación suicida e intención suicida con edad, estrato socioeconómico, estado civil, orientación sexual, las características de la enfermedad, el tratamiento antirretroviral y los aspectos piscoafectivos.

  13. La relazione empatica con i robot

    NARCIS (Netherlands)

    Marti, P.; Iacono, I.; Tittarelli, M.

    2013-01-01

    È possibile instaurare una relazione empatica tra un essere umano e un robot? Il presente studio valuta le soluzioni di design adottate nella progettazione di una maschera empatica, implementata su un tablet, che consente all’anziano di dialogare nell’ambiente domestico con un robot che lo assiste

  14. Sarcoma de Kaposi en paciente con SIDA

    Directory of Open Access Journals (Sweden)

    Jesús Ramón León Polanco

    2015-01-01

    Full Text Available Se presenta el caso de un paciente masculino de 33 años de edad, con antecedentes de VIH-SIDA desde hace 10 años, que se mantiene en tratamiento con antirretrovirales. Durante todo este tiempo ha presentado varios episodios de infecciones respiratorias, incluyendo tuberculosis pulmonar 5 años atrás. Acude a consulta refiriendo edemas en miembros inferiores acompañado de lesiones en piel de color violáceo de un año de evolución, previamente interpretado como linfangitis rebelde al tratamiento y que se extendió a la cara interna de los muslos y a los miembros inferiores. Con pérdida de peso, no prurito en las lesiones, fiebre, lesiones en la mucosa oral. Se determinó hemoglobina 89 g/L, leucocitos 4,5 x 109 /L, se estudiaron las funciones hepática y renales resultando normales. Radiografías de tórax y ultrasonido abdominal normales. Se realizó estudio anatomopatológico de piel que informó Sarcoma de Kaposi. Se impuso tratamiento con quimioterapia

  15. Las construcciones con esqueleto en madera

    Directory of Open Access Journals (Sweden)

    Heinz Leser S.

    1984-06-01

    Estos sistemas se emplean preferentemente en viviendas prefabricadas y edificios de pequeña envergadura. Finalmente, consideramos las construcciones con "esqueleto en madera", cuyo campo de aplicación principal está en las edificaciones de mediana extensión: escuelas, centros comunitarios, pequeñas industrias o bloques habitacionales.

  16. Conversazioni autobiografiche con Albino Sacco-Casamassima

    Directory of Open Access Journals (Sweden)

    Orazio Maria Valastro

    2004-03-01

    Full Text Available Nel 1948 venne Olivetti a Matera. Olivetti venne a Matera con un certo ambasciatore americano che praticamente aveva preparato o stava dando una mano per il piano Marschall, venne a Matera e mi vollero incontrare. Io sono stato chiamato dalla piazza, stavo nella piazza, era il mese di luglio, una cosa di questo genere, e andai in un bar, un bar ad angolo mi ricordo in Via Don Minzioni, dove questo Olivetti mi disse 'ma lei che cosa fa coi sassi?' 'Che cos'è questa storia?' Gli raccontai un po' che cosa facevo io con questi amici, avevamo fatto questo, insomma tutto quello che avevamo fatto nei sassi e che volevamo preparare ancora per presentare a qualcuno un piano di revisionamento dei sassi. Mi ricordo, era la prima volta che avevo visto Adriano Olivetti, ne avevo sentito parlare però non avevo mai visto quest'uomo con gli occhi celesti, minuto, coi capelli bianchi, riccioluto, con una cravatta bianca, cosa che mi fece impressione, una specie di angelo.

  17. Procesamiento de argumentos en personas con afasia

    Directory of Open Access Journals (Sweden)

    Luis Martínez

    2012-06-01

    Full Text Available En las personas con afasia se alteran diversos procesos lingüísticos. Entre las alteraciones más comunes tenemos aquellas que se producen en el procesamiento sintáctico, lo cual es evidente en el procesamiento de los argumentos. Investigaciones previas realizadas a sujetos con afasia reflejan un procesamientodeficiente de argumentos, lo cual se hace más evidente a medida que el número de argumentos aumenta. Se ha encontrado que mientras mayor es la complejidad en la estructura de la oración, los sujetos afásicos manifiestan mayores dificultades en el procesamiento de la misma. El presente estudio indaga en las dificultades que presentan los sujetos adultos con trastornos afásicos hablantes de español en el procesamiento de argumentos durante tareas de descripción. Este trabajo corrobora la evidencia de que los sujetos con afasia manifiestan un manejo deficiente en el procesamiento de argumentos en las tareas señaladas.

  18. Coriocarcinoma con metástasis pulmonar

    Directory of Open Access Journals (Sweden)

    Vicia Sánchez Abalos

    2014-05-01

    Full Text Available Se presenta el caso clínico de una fémina de 44 años de edad, con 32 semanas de embarazo, la cual fuera ingresada en la Unidad de Cuidados Intensivos del Hospital General Docente "Dr. Juan Bruno Zayas Alfonso" de Santiago de Cuba, por presentar insuficiencia respiratoria aguda como consecuencia de una sepsis. La paciente fue tratada con cefalosporina de tercera generación y ventilación mecánica no invasiva, pero se mantuvieron las características gasométricas de hipoxemia y una mala reacción terapéutica, por lo que se requirió instrumentación de las vías respiratorias y soporte hemodinámico, sin lograr regresión del cuadro clínico, lo cual condujo a un paro cardiorrespiratorio y, con ello, a la muerte. La necropsia mostró un coriocarcinoma del endometrio con metástasis pulmonar

  19. Con la testa fra le nuvole

    Directory of Open Access Journals (Sweden)

    André Greboge

    2015-06-01

    Full Text Available Partitura de Con la testa fra le nuvole, composta em 2015 para piano e harpa de pedais. Este memorial apresenta as notas sobre a obra e a organização do processo composicional, baseada em um insight composicional a partir da ideia de complexidade apresentada por James Tenney em Meta Meta-hodos (1988.

  20. REDUCCIÓN DE ÓXIDOSDE NITROGENO CON CATALIZADORES ZEOLÍTICOS INTERCAMBIADOS CON COBALTO

    Directory of Open Access Journals (Sweden)

    Enrique Alexis García Moya

    2012-10-01

    Full Text Available Se presenta un estudio sobre la reducción catalítica selectiva (RCS de NOx con metano en presencia de oxígeno en exceso con varios catalizadores a base de las zeolitas mordenita, ferrierita y ZSM-5 intercambiadas con diferentes cargas de cobalto y con las correspondientes zeolitas en forma acida. Cuando la mezcla reactiva contenía mayormente NO2 en lugar de NO, los catalizadores ácidos mostraron las más altas velocidades de formación de N2 en condiciones secas. Las mayores actividades se obtuvieron con los catalizadores Co-mordenita, siguiendo en orden de actividad los catalizadores Co-Ferrierita y Co-ZSM-5. El catalizador Co-Mordenita más activo se ensayó con una mezcla reactiva donde predominó el NO en lugar del NO2 bajo condiciones secas e hidrotérmicas y en presencia de SO2. Con la adición de 8% de agua a la mezcla de reacción se observó desactivación reversible, especialmente a bajas temperaturas. La adición de 60 ppm de SO2 disminuyó la velocidad de reacción aproximadamente a la mitad debido posiblemente al envenenamiento de algunos sitios activos.

  1. Manejo de conductos radiculares con curvatura marcada

    Directory of Open Access Journals (Sweden)

    Jorge Mario Nuñez Duran

    2013-10-01

    Full Text Available Las variaciones anatómicas en dientes con conductos que poseen dilaceraciones hacen del tratamiento de endodonciaun reto o una complicación relativa, en donde el clínico debe desarrollar toda su habilidad y el uso de instrumentosespeciales que faciliten u optimicen la terapia de conductos radiculares. La toma de radiografías previas con diferentesangulaciones y el estudio minucioso de ellas, darán una ayuda fundamental para conocer más detalladamente estacomplicación anatómica, que en algunos casos es muy frecuente. El uso de instrumental más flexible y resistentepermite llegar con mayor precisión y seguridad a la parte apical sin que se corra el riesgo de fracturar los instrumentos,limpiándolos y modelándolos en toda su extensión para poder obturarlos de una manera correcta.El uso de limas de menor calibre, precurvadas, permite acceder a la porción dilacerada de la raíz. Este es un métodoeficaz para prevenir la perdida de longitud de trabajo y evitar así las perforaciones de las raíces durante la preparación.Dentro de los errores más comunes durante la instrumentación de los conductos está la perdida de longitud detrabajo, junto con la transportación del foramen apical, ya sea de manera externa o interna. En el presente artículose menciona el uso de nuevas y mejores técnicas usadas para poder evitar este tipo de errores y se muestra un casoclínico del manejo de un molar superior con una curvatura de 40 grados que fue preparado y obturado exitosamentecon el sistema Protaper (Dentsply- maillefer.

  2. Variables socionutricionales de hogares mazahuas integrados por preescolares desnutridos con madres con obesidad y sin obesidad

    OpenAIRE

    Viridiana Vanessa Conzuelo-González

    2009-01-01

    El primer objetivo fue conocer cuántos menores de cinco años con diferentes grados de desnutrición tienen una madre con sobrepeso/obesidad/ en una comunidad indígena que vive en extrema pobreza y bajo condiciones de migración masculina internacional. El segundo fue comparar tres variables socionutricionales (ingreso familiar, educación de la madre y adecuación nutrimental de la dieta diaria) entre estos hogares y los hogares con desnutrición infantil y madres sin obesidad. Se realizó un estud...

  3. Terapias alternativas con animales para niños con necesidades especiales

    OpenAIRE

    Cea-Chueca, Aihnoa

    2014-01-01

    El presente trabajo de fin de grado consiste en la realización de un análisis y descripción de la literatura acerca de las distintas terapias animales, destinadas a niños con necesidades especiales: cómo y por qué surgieron, en qué consisten las terapias, cómo podemos utilizarlas, etc. Las terapias alternativas con animales se conocen como una alternativa terapéutica, donde se utiliza a un animal como co-terapeuta para poder desarrollar diferentes capacidades de los niños con necesidades espe...

  4. Variables socionutricionales de hogares mazahuas integrados por preescolares desnutridos con madres con obesidad y sin obesidad

    OpenAIRE

    Viridiana Vanessa Conzuelo-González; Ivonne Vizcarra-Bordi

    2009-01-01

    El primer objetivo fue conocer cuántos menores de cinco años con diferentes grados de desnutrición tienen una madre con sobrepeso/obesidad/ en una comunidad indígena que vive en extrema pobreza y bajo condiciones de migración masculina internacional. El segundo fue comparar tres variables socionutricionales (ingreso familiar, educación de la madre y adecuación nutrimental de la dieta diaria) entre estos hogares y los hogares con desnutrición infantil y madres sin obesidad. Se realizó un est...

  5. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1997-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  6. Optimal expansion planning of stand-alone systems with stochastic simulations

    Energy Technology Data Exchange (ETDEWEB)

    Hoese, Alejandro [Instituto de Energia Electrica (IEE), Universidad Nacional de San Juan, (Argentina)

    1998-12-31

    Stand-alone systems in the range of 1 kW - 10 MW are taking relevance in the new (global) liberal concept of energy market. State and private investors are becoming increasingly attention on the use of renewable for these systems, but it must be shown that these non-conventional solutions are competitive with the established conventional ones. The high investment costs and the technical and economic uncertainties coupled with the use of time-dependent energy sources are the mainly inhibiting factors for the decision agents to choose these systems instead of conventional ones. In the paper a new model for optimal expansion planning of hybrid stand-alone generating systems under consideration of uncertainties is presented. This model is at present in {sup d}evelopment state{sup .} Results already obtained in the first steps of this research are promising and some of them are here presented. [Espanol] Los sistemas autocontenidos en el rango de 1 Kw a 10 MW estan tomando importancia en el nuevo (global) concepto liberal del mercado de la energia. Inversionistas privados y del Estado estan poniendo mayor atencion en el uso de energias renovables para estos sistemas, pero debe mostrarse que estas soluciones no-convencionales son competitivas con las convencionales establecidas. Los altos costos de inversion y las incertidumbres tecnicas y economicas aunadamente con el uso de fuentes de energia dependientes del tiempo son los principales factores inhibidores de los factores de decision para escoger estos sistemas en lugar de los convencionales. En este articulo se presenta un nuevo modelo de planeacion de expansion optima de sistemas hibridos autocontenidos de generacion electrica bajo la consideracion de incertidumbres. Este modelo esta actualmente en {sup e}stado de desarrollo{sup .} Los resultados ya obtenidos en las primeras etapas de esta investigacion son prometedores y se presentan algunos de ellos.

  7. Relación del desarrollo cognitivo con el clima familiar y el estrés de la crianza Relationship of the cognitive development with the family clime and stress of the childrearing

    Directory of Open Access Journals (Sweden)

    José Ángel Vera Noriega

    2005-12-01

    Full Text Available Se llevo a cabo un estudio con 120 familias en pobreza extrema de las zonas marginales de Hermosillo, Sonora México. Madres de 32 años en promedio respondieron a una escala de funcionamiento familiar, estrés de la crianza y sus niños fueron medidos en desarrollo cognitivo. El objetivo fue evaluar las diferencias significativas entre los tres tipos de familias en su desarrollo cognitivo, el estrés de la crianza y el clima familiar. Se clasificaron las familias en base a la medida de clima familiar con un análisis de conglomerados (clusters. Los resultados indican: a tres tipos de climas, que etiquetamos como, disciplinado, cohesionado y sin orientación; b clima sin orientación se asocia a una percepción negativa del niño y de restricciones por la maternidad y presentan las medias mas bajas de desarrollo cognitivo; c el clima cohesivo se asocia con menos estrés en la madre por la crianza y los puntajes mas alto de desarrollo cognitivo.A study was performed over 120 families located in the marginal areas of Hermosillo, Sonora, Mexico. Mothers whose age averaged 32 years old responded to a scale of family performance and childrearing stress; their children were measured throughout cognitive development. This study was aimed to evaluate significant differences with regards to cognitive development, child-rearing stress and family environment among the three types of family. The families were classified based on a measurement of family environment with a cluster analysis. Consequently, the results indicate the following: a Three different types of environment, which were labeled as disciplined, in harmony and without direction; b the environment without direction becomes associated to a negative perception of the child and motherhood restrictions, resulting with the lowest average of cognitive development, thus; c the cohesive environment becomes associated with a lower level of stress in the mother induced by child-rearing and with the

  8. Wilson's operator expansion: can it fail

    International Nuclear Information System (INIS)

    Novikov, V.A.; Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.

    1984-01-01

    The status of poperator product expansion (OPE) in the presence of nonperturbative effects is duscussed within the framework of some simople models 4d Higgs model, 2d sigma-model and Schwinger model are considered. The general formulation of OPE is presented and it is demonstrated that there exists a consistent procedure allowing one to define unabiguously both coefficient functions and matrix elements of compositie operators. One of the key elements of the procedure is introduction of an auxiliary paramparameter, the normalization point μ. The two extremss considered are lambda phi 4 theory with no spontaneous breaking of the symmetry and O(N) sigma model in the limit N→infinity. In the former case there is only perturbative contribution to (phi 2 ) while in the latter case the perturbative pieces are suppressed by 1/N factors. Numerically QCD is much closer to the O(N) sigma model in the large N limit. Comments on specific features of QCD are presented

  9. Density-functional expansion methods: Grand challenges.

    Science.gov (United States)

    Giese, Timothy J; York, Darrin M

    2012-03-01

    We discuss the source of errors in semiempirical density functional expansion (VE) methods. In particular, we show that VE methods are capable of well-reproducing their standard Kohn-Sham density functional method counterparts, but suffer from large errors upon using one or more of these approximations: the limited size of the atomic orbital basis, the Slater monopole auxiliary basis description of the response density, and the one- and two-body treatment of the core-Hamiltonian matrix elements. In the process of discussing these approximations and highlighting their symptoms, we introduce a new model that supplements the second-order density-functional tight-binding model with a self-consistent charge-dependent chemical potential equalization correction; we review our recently reported method for generalizing the auxiliary basis description of the atomic orbital response density; and we decompose the first-order potential into a summation of additive atomic components and many-body corrections, and from this examination, we provide new insights and preliminary results that motivate and inspire new approximate treatments of the core-Hamiltonian.

  10. Can snowshoe hares control treeline expansions?

    Science.gov (United States)

    Olnes, Justin; Kielland, Knut; Juday, Glenn P; Mann, Daniel H; Genet, Hélène; Ruess, Roger W

    2017-10-01

    Treelines in Alaska are advancing in elevation and latitude because of climate warming, which is expanding the habitat available for boreal wildlife species, including snowshoe hares (Lepus americanus). Snowshoe hares are already present in tall shrub communities beyond treeline and are the main browser of white spruce (Picea glauca), the dominant tree species at treeline in Alaska. We investigated the processes involved in a "snowshoe hare filter" to white spruce establishment near treeline in Denali National Park, Alaska, USA. We modeled the pattern of spruce establishment from 1970 to 2009 and found that fewer spruce established during periods of high hare abundance. Multiple factors interact to influence browsing of spruce, including the hare cycle, snow depth and the characteristics of surrounding vegetation. Hares are abundant at treeline and may exclude spruce from otherwise optimal establishment sites, particularly floodplain locations with closed shrub canopies. The expansion of white spruce treeline in response to warming climate will be strongly modified by the spatial and temporal dynamics of the snowshoe hare filter. © 2017 by the Ecological Society of America.

  11. Oil refining expansion criteria for Brazil

    International Nuclear Information System (INIS)

    Tavares, M.E.E.; Szklo, A.S.; Machado, G.V.; Schaeffer, R.; Mariano, J.B.; Sala, J.F.

    2006-01-01

    This paper assesses different strategies for the expansion of Brazil's oil refining segment, using criteria that range from energy security (reducing imports and vulnerability for key products) through to maximizing the profitability of this sector (boosting the output of higher value oil products) and adding value to Brazil's oil production (reducing exports of heavy acid oil). The development prospects are analyzed for conventional fuel production technology routes, sketching out three possible refining schemes for Brazilian oil and a GTL plant for producing gasoil from natural gas. Market scenario simulations indicate that investments will be required in Brazil's oil refining segment over and above those allocated to planned modifications in its current facilities, reducing the nation's vulnerability in terms of gasoil and petrochemical naphtha imports. Although not economically attractive, oil refining is a key activity that is crucial to oil company strategies. The decision to invest in this segment depends on local infrastructure conditions, environmental constraints and fuel specifications, in addition to oil company strategies, steady growth in demand and the definition of a government policy that eases institutional risks. (author)

  12. Oil refining expansion criteria for Brazil

    International Nuclear Information System (INIS)

    Tavares, Marina Elisabete Espinho; Szklo, Alexandre Salem; Machado, Giovani Vitoria; Schaeffer, Roberto; Mariano, Jacqueline Barboza; Sala, Janaina Francisco

    2006-01-01

    This paper assesses different strategies for the expansion of Brazil's oil refining segment, using criteria that range from energy security (reducing imports and vulnerability for key products) through to maximizing the profitability of this sector (boosting the output of higher value oil products) and adding value to Brazil's oil production (reducing exports of heavy acid oil). The development prospects are analyzed for conventional fuel production technology routes, sketching out three possible refining schemes for Brazilian oil and a GTL plant for producing gasoil from natural gas. Market scenario simulations indicate that investments will be required in Brazil's oil refining segment over and above those allocated to planned modifications in its current facilities, reducing the nation's vulnerability in terms of gasoil and petrochemical naphtha imports. Although not economically attractive, oil refining is a key activity that is crucial to oil company strategies. The decision to invest in this segment depends on local infrastructure conditions, environmental constraints and fuel specifications, in addition to oil company strategies, steady growth in demand and the definition of a government policy that eases institutional risks

  13. The consequences of expansion joint bellows failure

    International Nuclear Information System (INIS)

    Miller, R.F.; Daugherty, W.L.

    1993-01-01

    Expansion joint (EJ) bellows are thin walled, flexible components of a piping system. As such, they usually are the weakest structural link in the pressure boundary from a failure probability perspective. Previously, a 360 degrees, circumferential rupture of a bellows was conservatively assumed to cause bellows collapse due to internal pressure resulting in a double-ended guillotine break (DEGB) and the associated, large leak rate. A finite element analysis was performed to determine the structural response of a ruptured bellows and its ability to resist large opening areas and hence, large leak rates. The results show that a 360 degrees break can lead to an opening width of up to 0.7 inch following an instantaneous rupture -- provided the equalizing rings and tie rods remain intact. This would result in an initial leak rate reduction equal to 80% of the previously assumed DEGB flow. The reduced flow rate is less than the water removal system capacity-assuring that flooding will not occur

  14. Testing option pricing with the Edgeworth expansion

    Science.gov (United States)

    Balieiro Filho, Ruy Gabriel; Rosenfeld, Rogerio

    2004-12-01

    There is a well-developed framework, the Black-Scholes theory, for the pricing of contracts based on the future prices of certain assets, called options. This theory assumes that the probability distribution of the returns of the underlying asset is a Gaussian distribution. However, it is observed in the market that this hypothesis is flawed, leading to the introduction of a fudge factor, the so-called volatility smile. Therefore, it would be interesting to explore extensions of the Black-Scholes theory to non-Gaussian distributions. In this paper, we provide an explicit formula for the price of an option when the distributions of the returns of the underlying asset is parametrized by an Edgeworth expansion, which allows for the introduction of higher independent moments of the probability distribution, namely skewness and kurtosis. We test our formula with options in the Brazilian and American markets, showing that the volatility smile can be reduced. We also check whether our approach leads to more efficient hedging strategies of these instruments.

  15. Virial expansion for almost diagonal random matrices

    International Nuclear Information System (INIS)

    Yevtushenko, Oleg; Kravtsov, Vladimir E

    2003-01-01

    Energy level statistics of Hermitian random matrices H-circumflex with Gaussian independent random entries H i≥j is studied for a generic ensemble of almost diagonal random matrices with (vertical bar H ii vertical bar 2 ) ∼ 1 and (vertical bar H i≠j vertical bar 2 ) bF(vertical bar i - j vertical bar) parallel 1. We perform a regular expansion of the spectral form-factor K(τ) = 1 + bK 1 (τ) + b 2 K 2 (τ) + c in powers of b parallel 1 with the coefficients K m (τ) that take into account interaction of (m + 1) energy levels. To calculate K m (τ), we develop a diagrammatic technique which is based on the Trotter formula and on the combinatorial problem of graph edges colouring with (m + 1) colours. Expressions for K 1 (τ) and K 2 (τ) in terms of infinite series are found for a generic function F(vertical bar i - j vertical bar ) in the Gaussian orthogonal ensemble (GOE), the Gaussian unitary ensemble (GUE) and in the crossover between them (the almost unitary Gaussian ensemble). The Rosenzweig-Porter and power-law banded matrix ensembles are considered as examples

  16. Inadvertent pump start with gas expansion modules

    International Nuclear Information System (INIS)

    Campbell, L.R.; Harris, R.A.; Heard, F.J.; Dautel, W.A.

    1992-01-01

    Previous testing demonstrated the effectiveness of gas expansion modules (GEMs) in mitigating the consequences of a loss-of-flow-without-scram transient in Fast Flux Test Facility (FFTF)-sized sodium cooled cores. As a result, GEMs have been included in the advance liquid-metal reactor (PRISM) design project sponsored by the US Department of Energy. The PRISM design is under review at the US Nuclear Regulatory Commission for licensability. In the unlikely event that the reactor does not scram during a loss of low, the GEMs quickly insert sufficient negative reactivity to limit fuel and cladding temperatures to acceptable values. This is the positive benefit of the GEMs; however, the reverse situation must be considered. A primary pump could be inadvertently started from near-critical conditions resulting in a positive reactivity insertion and a power transient. One mitigating aspect of this event is that as the reactivity associated with the GEMs is inserted, the increasing flow increases core cooling. A test was conducted in the FFTF to demonstrate that the GEM and feedback reactivity are well predicted following pump start, and the reactivity transient is benign

  17. Compression and expansion in central collisions

    International Nuclear Information System (INIS)

    Danielewicz, P.

    1997-01-01

    Dynamics of central collisions of heavy nuclei in the energy range from few tens of MeV/nucleon to a couple of GeV/nucleon is discussed. As the beam energy increases and/or the impact parameter decreases, the maximum compression increases. It is argued that the hydrodynamic behaviour of matter sets in the vicinity of balance energy. At higher energies shock fronts are observed to form within head-on reaction simulations, perpendicular to beam axis and separating hot compressed matter from cold. In the semi-central reactions a weak tangential discontinuity develops in-between these fronts. The hot compressed matter exposed to the vacuum in directions parallel to the shock front begin to expand collectively into these directions. The expansion affects particle angular distributions and mean energy components and further shapes of spectra and mean energies of particles emitted into any one direction. The variation of slopes and the relative yields measured within the FOPI collaboration are in a general agreement with the results of simulations. As to the FOPI data on stopping, they are consistent with the preference for transverse over the longitudinal motion in the head-on Au + Au collisions. Unfortunately, though, the data can not be used to decide directly on that preference due to acceptance cuts. Tied to the spatial and temporal changes in the reactions are changes in the entropy per nucleon. (authors)

  18. Global sensitivity analysis using polynomial chaos expansions

    International Nuclear Information System (INIS)

    Sudret, Bruno

    2008-01-01

    Global sensitivity analysis (SA) aims at quantifying the respective effects of input random variables (or combinations thereof) onto the variance of the response of a physical or mathematical model. Among the abundant literature on sensitivity measures, the Sobol' indices have received much attention since they provide accurate information for most models. The paper introduces generalized polynomial chaos expansions (PCE) to build surrogate models that allow one to compute the Sobol' indices analytically as a post-processing of the PCE coefficients. Thus the computational cost of the sensitivity indices practically reduces to that of estimating the PCE coefficients. An original non intrusive regression-based approach is proposed, together with an experimental design of minimal size. Various application examples illustrate the approach, both from the field of global SA (i.e. well-known benchmark problems) and from the field of stochastic mechanics. The proposed method gives accurate results for various examples that involve up to eight input random variables, at a computational cost which is 2-3 orders of magnitude smaller than the traditional Monte Carlo-based evaluation of the Sobol' indices

  19. Global sensitivity analysis using polynomial chaos expansions

    Energy Technology Data Exchange (ETDEWEB)

    Sudret, Bruno [Electricite de France, R and D Division, Site des Renardieres, F 77818 Moret-sur-Loing Cedex (France)], E-mail: bruno.sudret@edf.fr

    2008-07-15

    Global sensitivity analysis (SA) aims at quantifying the respective effects of input random variables (or combinations thereof) onto the variance of the response of a physical or mathematical model. Among the abundant literature on sensitivity measures, the Sobol' indices have received much attention since they provide accurate information for most models. The paper introduces generalized polynomial chaos expansions (PCE) to build surrogate models that allow one to compute the Sobol' indices analytically as a post-processing of the PCE coefficients. Thus the computational cost of the sensitivity indices practically reduces to that of estimating the PCE coefficients. An original non intrusive regression-based approach is proposed, together with an experimental design of minimal size. Various application examples illustrate the approach, both from the field of global SA (i.e. well-known benchmark problems) and from the field of stochastic mechanics. The proposed method gives accurate results for various examples that involve up to eight input random variables, at a computational cost which is 2-3 orders of magnitude smaller than the traditional Monte Carlo-based evaluation of the Sobol' indices.

  20. The optimizied expansion method for wavefield extrapolation

    KAUST Repository

    Wu, Zedong

    2013-01-01

    Spectral methods are fast becoming an indispensable tool for wave-field extrapolation, especially in anisotropic media, because of its dispersion and artifact free, as well as highly accurate, solutions of the wave equation. However, for inhomogeneous media, we face difficulties in dealing with the mixed space-wavenumber domain operator.In this abstract, we propose an optimized expansion method that can approximate this operator with its low rank representation. The rank defines the number of inverse FFT required per time extrapolation step, and thus, a lower rank admits faster extrapolations. The method uses optimization instead of matrix decomposition to find the optimal wavenumbers and velocities needed to approximate the full operator with its low rank representation.Thus,we obtain more accurate wave-fields using lower rank representation, and thus cheaper extrapolations. The optimization operation to define the low rank representation depends only on the velocity model, and this is done only once, and valid for a full reverse time migration (many shots) or one iteration of full waveform inversion. Applications on the BP model yielded superior results than those obtained using the decomposition approach. For transversely isotopic media, the solutions were free of the shear wave artifacts, and does not require that eta>0.