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Sample records for field equilibrio gaseoso

  1. Gaseous equilibrium in sector CP IV of the Cerro Prieto, B.C. Mexico geothermal field; Equilibrio gaseoso en el sector CP IV del campo geotermico Cerro Prieto, B.C., Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel; Portugal Marin, Enrique [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico); De Leon Vivar, Jesus [Comision Federal de Electricidad, Campo Geotermico Cerro Prieto, Cerro Prieto, B. C. (Mexico)

    2007-07-01

    Sector CP IV is located in the NE portion of the Cerrro Prieto geothermal field. The wells of this zone produce two-phase fluids, with different characteristics as far as their steam fraction content; in the central part and towards the NW the fluids are of dominant liquid type whereas towards the E and the S, the fluid contains a relatively higher steam fraction. The results of gaseous equilibrium FT- HSH3 showed that the fluids in the deposit are at temperatures between 275 Celsius degrees and 310 Celsius degrees and contain steam fractions between 0.01 and 0.5. The data found for the natural state are aligned in a tendency defined in the diagram FT- HSH3, that suggest the wells receive different proportions from preexisting steam in the deposit, which are mixed with the liquid phase to produce the observed discharges. The present data, besides showing the presence of deposit steam, also indicates the entrance of lower temperature fluid in the central part of sector CP IV. [Spanish] El sector CP IV se localiza en la porcion NE del campo geotermico Cerro Prieto. Los pozos de esta zona producen fluidos bifasicos, con diferentes caracteristicas en cuanto a su contenido de fraccion de vapor: en la parte central y hacia el NW los fluidos son de tipo liquido dominante mientras que hacia el E y hacia el S, el fluido contiene una fraccion relativamente alta de vapor. Los resultados de equilibrio gaseoso FT-HSH3 mostraron que los fluidos en el yacimiento se encuentran a temperaturas de entre 275 grados Celsius y 310 grados Celsius y contienen fracciones de vapor de entre -.01 y .5. Los datos hallados para el estado natural se alinean en una tendencia definida en el diagrama FT-HSH3, que sugiere que los pozos reciben diferentes proporciones de vapor pre-existente en el yacimiento, que se mezclan con fase liquida para producir las descargas que se observan. Los datos actuales, ademas de mostrar la presencia de vapor de yacimiento, tambien indican la entrada de fluidos de

  2. Two-phase characteristics of the feeding fluid of Cerro Prieto IV wells (Mexico) obtained by gas equilibrium; Caracteristicas bifasicas del fluido de alimentacion de pozos de Cerro Prieto IV (Mexico), obtenidas por equilibrio gaseoso

    Energy Technology Data Exchange (ETDEWEB)

    Barragan-Reyes, Rosa Maria; Arellano-Gomez, Victor Manuel; Portugal-Marin, Enrique [Instituto de Investigaciones Electricas (Mexico); De Leon-Vivar, Jesus [Comision Federal de Electricidad, Residencia General de Cerro Prieto, B.C (Mexico)

    2008-10-15

    The gas composition of fluids produced by CP IV geothermal wells from the Cerro Prieto field was studied in order to identify different types of fluids entering the wells by estimating their temperature and excess steam. A method based on the Fischer Tropsch reaction and H2S equilibrium with pyrite-pyrrhotite as mineral buffer (FTHSH3) was used. The results for the reservoir natural state indicated the presence of fluids with heterogeneous reservoir temperature (between 275 and 310 degrees Celsius) and excess steam values, which were found from negative (boiled liquid that has lost steam when flowing to the well) to one (steam phase with zero liquid saturation). The study for individual wells in which boiling processes were identified, showed that through time, the feeding fluids consist of a two-phase mixture with different liquid/steam proportions. Also, the results suggested that a steam phase could occur at CP IV which is added to the feeding fluid, depending on the operation conditions of the wells. The origin of this steam could be the boiling of the deeper liquid due to a pressure drop. [Spanish] Se estudio la composicion gaseosa de los fluidos producidos por pozos geotermicos del sector CP IV del campo de Cerro Prieto para tratar de distinguir aportes de fluidos diferentes mediante la estimacion de su temperatura de yacimiento y del exceso de vapor. Se utilizo un metodo de equilibrio gaseoso basado en la reaccion de Fischer Tropsch y el equilibrio combinado pirita-pirrotita (FT-HSH3). Los resultados obtenidos indican que en el estado inicial del yacimiento existen fluidos que muestran heterogeneidad en los valores de temperatura de yacimiento (entre 275 y 310 grados Celsius), asi como en el exceso de vapor con valores desde negativos (liquido que despues de ebullir ha perdido vapor en su trayecto hacia el pozo) hasta uno (vapor con cero saturacion de liquido). El estudio individual de los pozos con fenomenos de ebullicion muestra que a traves del tiempo

  3. Equilibrios ácido-base

    OpenAIRE

    Barciela García, Julia; Peña Crecente, Rosa María

    2010-01-01

    Nesta unidade repasaranse os fundamentos dos equilibrios ácidobase(tanto de ácidos e bases fortes como débiles), as súas constantes de equilibrio e os cálculos de concentracións para todas as especies participantes nos mesmos. Dentro da unidade tamén se tratará con especial detalle o concepto de disolucións reguladoras (preparación, cálculo de pH, mecanismos de regulación). Por último como aplicación práctica, a unidade centrarase no estudo das volumetrías ácido-base, as cales se usan en moit...

  4. Diversidad de sistemas planetarios sin gigantes gaseosos en discos de baja masa

    OpenAIRE

    Ronco, María Paula

    2013-01-01

    Como indica el título de esta tesis, el objetivo general de nuestro trabajo es poder analizar la diversidad de sistemas planetarios que podrían formarse alrededor de estrellas de tipo solar y sin gigantes gaseosos. Nuestro interés particular es estudiar estos sistemas en discos de baja masa, pues podemos asegurar que en ellos no hay posibilidad de formar planetas gigantes gaseosos. Para poder lograr este análisis desarrollamos simulaciones de N-cuerpos orientadas a estudiar el proceso de form...

  5. Chemical Equilibrium and Mineral Saturation in Waters from Oil Wells of the Activo Luna Field, Tabasco, Mexico; Equilibrio quimico y grado de saturacion de minerales en aguas de pozos petroleros de Activo Luna, Tabasco, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa Maria; Arellano G, Victor M.; Portugal M, Enrique; Torres R, Vicente [Instituto de Investigaciones Electricas (Mexico); Torres Alvarado, Ignacio [Universidad Nacional Autonoma de Mexico (Mexico); Ascencio C, Fernando; Martinez A; Ana E [Petroleos Mexicanos (Mexico)

    2001-09-01

    Chemical equilibrium of formation waters from seven oil wells of the Activo Luna field (Tabasco, Mexico) was modelled. Saturation indices of characteristic hydrothermal minerals were calculated at ambient and reservoir conditions in order to predict scaling potential of deep and surface installations. The salinity of waters was found to be in the range from 43,000 (well Escuintle 2) to 250,000 (well Lune 3B) mg/kg as total dissolved solids. The water samples were classified as sodium-chioride type. Ionic strength for the solutions was found to be between 0.75 and 6.5. Activity coefficients were estimated by virial (Pitzer equations) methods using the GEOCHEMIST WORKENCH (GWB) software. Minerals such as anhydrite, halite, alunite, fluorite and barite were found to be supersaturated at reservoir conditions. A solid scale sample obtained from well Luna-3B was analysed. Analysis indicate the presence of calcite, anhydrite, fluorite and sphalerite which suggest the occurrence of temperatures of at least 180 Celcius degrees with acidic conditions and high chemical corrosion potential. [Spanish] Se modelo el equilibrio quimico de aguas de formacion producidas por siete pozos petroleros pertenecientes al Activo Luna, en el estado de Tabasco, Mexico, se calcularon los indices de saturacion de minerales caracteristicos tanto en las condiciones ambiente como en las de yacimiento, con el proposito de apoyar el control de incrustaciones en las instalaciones superficiales y profundas. La salinidad de las salmueras se encontro en el rango de 43,000 (pozos Escuintle 2) a 250,000 (pozos Luna 3B) mg/kg de solidos disueltos totales y las muestras se clasificaron como del tipo clorurado-sodico. La fuerza ionica de las soluciones varia entre 0.75 y 6.5 molar, por lo que los coeficientes de actividad de la modelacion de equilibrio quimico se estimaron por metodos viriales empleando las ecuaciones de Pitzer mediante el programa GEOCHEMIST WORKBENCH (GWB). Minerales como anhidrita, halita

  6. Equilibrio walrasiano en economías de intercambio

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    Osvaldo Acuña Ortega

    2009-02-01

    Full Text Available Se presentan las funciones de exceso de demanda agregada de una economía de intercambio. Se estudian las propiedades y los vectores de precios de equilibrio de dichas funciones. Se prueba que el equilibrio walrasiano es un óptimo de Pareto. Se estudia el concepto de economía regular y se aprueba la existencia de equilibrio walrasiano, para dicha economía. Por último, estudiamos la unicidad del vector de precios de equilibrio.

  7. Efecto del intercambio gaseoso sobre el crecimiento y tuberización de vitroplantas de papa

    OpenAIRE

    Lugo G, J.G; Mogollón, N; Rodríguez, Z.F; Díaz, J.G

    2009-01-01

    La incorporación de microtubérculos de papa es una alternativa importante en los programas de producción de semilla en Lara, Venezuela. Para estudiar los factores que afectan la obtención de microtubérculos, se evaluaron vitroplantas de papa, sometidas a tres condiciones de intercambio gaseoso: alta (tapas de gasa), media (tapa plástica) y baja (tapa sellada con envoltura plástica), sembrando bajo condiciones estériles dos microesquejes uninodales con una yema axilar, de las variedades Andini...

  8. Posición prona: efecto sobre el intercambio gaseoso y en la capacidad funcional para el ejercicio en pacientes con hipertensión pulmonar

    OpenAIRE

    Bastidas-L, Andrea Carolina; Colina-Chourio, José A; Guevara, Jesnel M; Núñez, Alexis

    2015-01-01

    El objetivo del estudio fue evaluar el intercambio gaseoso y el comportamiento funcional cardiorrespiratorio en pacientes con hipertensión pulmonar (HTP) antes, durante y después del cambio de posición a decúbito prono. Treinta pacientes con HTP y alteraciones en el intercambio gaseoso fueron incluidos en el estudio. Las variables de intercambio gaseoso se evaluaron en decúbito supino para obtener los valores basales y en decúbito prono a los 30, 120 y 240 min. Así mismo, se sometieron al tes...

  9. El punto de equilibrio: herramienta de control

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    Pedro A. López Guzman

    1986-04-01

    Full Text Available RESUMEN Aunque el control sea solamente uno de los elementos del Proceso Administrativo, es sin lugar a dudas, el que contribuye mas a mejorar las actuaciones de la Empresa de aqui la importancia de conocer las herramientas para aplicarlo. En el Siguiente artículo se estudia el punto de equilibrio como herramienta de  control y comprende su definición, sus componentes y otros aspectos importantes que conllevan a controlar eficazmente los diversos aspectos de la empresa

  10. El concepto de equilibrios múltiples en ciencias sociales

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    Luis Fernando Medina

    2011-06-01

    Full Text Available El concepto de equilibrio se ha convertido en el eje central del análisis económico moderno. Más aún, ha sido este mismo concepto el que ha dado ímpetu a la expansión de la teoría económica hacia esferas de las ciencias sociales que antes le eran ajenas. El presente artículo busca explicar el proceso de cambio en la ciencia económica que ha llevado a esta situación, así como ofrecer una discusión somera de los fundamentos del concepto de equilibrio, sus fortalezas, los retos metodológicos que plantea, en especial en el caso de los “equilibrios múltiples”, y esbozar algunas alternativas para abordar dichos desafíos

  11. Mejoras del Método Pilates en el equilibrio

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    Sobrín-Valbuena, C.V.; Montil Jiménez, Marta Matilde; García López, Óscar

    2013-01-01

    Pilates es un método de acondicionamiento físico cuyos beneficios se han extendido al mundo sanitario. Diferentes estudios muestran que, entre otros beneficios, Pilates ayuda a mejorar la postura. Una evaluación objetiva de la misma puede ser obtenida por el análisis del equilibrio. El propósito del estudio fue evaluar, mediante plataforma de presiones, el equilibrio en dos grupos, los que realizan Pilates y los que no lo realizan. Se evaluaron a 124 personas divididos en dos grupos: 59 perso...

  12. El equilibrio económico en los contratos administrativos

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    Libardo Rodriguez

    2011-12-01

    Full Text Available El estudio aborda el principio del equilibrio en los contratos administrativos como prinicipio específico de esa clase de contratos, tanto en el Derecho comparado como en el Derecho colombiano. Para el efecto se precisa el concepto y se analizan los antecedentes históricos y el origen de la figura, la justificación e la existencia de principio, las condiciones generales para la procedencia de su aplicación, los instrumentos jurídicos existentes para su efectividad y las causales específicas que dan lugar a la ruptura del equilibrio económico.

  13. Debilidades de la teoría del equilibrio general

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    Hortencia Rueda Lizarazo

    2013-08-01

    Full Text Available El objeto de este documento es plantear inquietudes respecto a las hipótesis básicas de la economía que soportan el modelo del equilibrio general. El modelo Walrasiano ha sido el soporte teórico de la enseñanza económica, sin embargo muchos de sus supuestos han sido y son fuente de fuertes críticas debido a su imposibilidad de explicar la realidad. Este articulo iniciará con una exposición de la teoría del equilibrio general, analizando sus rasgos generales sobre el concepto de individualismo metodológico, oferta y demanda y análisis de formación de precios, seguidamente las principales críticas que hacen vulnerable la TEGW de autores como Benetti, Cataño, Colander, Ackerman entre otros, como una base real del estudio económico.

  14. El concepto de equilibrios múltiples en ciencias sociales

    OpenAIRE

    Luis Fernando Medina

    2011-01-01

    El concepto de equilibrio se ha convertido en el eje central del análisis económico moderno. Más aún, ha sido este mismo concepto el que ha dado los ímpetus para la expansión de la teoría económica hacia esferas de las ciencias sociales que antes le eran ajenas. El presente artículo busca explicar el proceso de cambio en la ciencia económica que ha llevado a esta situación, así como ofrecer una discusión somera de los fundamentos del concepto de equilibrio, sus fortalezas, los retos metodológ...

  15. El concepto de equilibrios múltiples en ciencias sociales

    OpenAIRE

    Medina, Luis Fernando

    2011-01-01

    El concepto de equilibrio se ha convertido en el eje central del análisis económico moderno. Más aún, ha sido este mismo concepto el que ha dado ímpetu a la expansión de la teoría económica hacia esferas de las ciencias sociales que antes le eran ajenas. El presente artículo busca explicar el proceso de cambio en la ciencia económica que ha llevado a esta situación, así como ofrecer una discusión somera de los fundamentos del concepto de equilibrio, sus fortalezas, los retos metodológicos que...

  16. Estudio de las características del intercambio gaseoso de variedades de geranio en cultivo protegido en zonas de clima mediterráneo

    OpenAIRE

    Sant i Vilella, M. Dolors

    1987-01-01

    [spa] En plantas de geranio dedicadas a la producción de esquejes (Pelargonium x hortorum cv. Orange Ricard, P. grandiflorum cv. FJamingo y P. peltatum cv. Old Lady, cultivadas en contenedor, en substrato artificial, en un invernadero comercial) se realizaron series estacionales de medidas del intercambio gaseoso en laboratorio en respuesta a cambios de irradiancia, temperatura y humedad del aire, y se determinaron en el invernadero la respuesta en el ciclo diario de la fotosíntesis neta, tra...

  17. Repercusión de los esguinces de tobillo sobre el equilibrio postural

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    Laura Martín-Casado

    2015-09-01

    Full Text Available Objetivo. Analizar las diferencias intrasujeto en el equilibrio postural durante la realización de test de equilibrio estáticos y dinámico – funcionales, entre una extremidad que presentó signo de bostezo articular en el tobillo, fruto de una lesión previa de esguince lateral, frente a una extremidad sin bostezo.

  18. Equilibrio de Nash y resolución de conflictos

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    Maritza Vanegas de Medina

    2014-01-01

    Full Text Available En el presente artículo, se introduce la noción de juegos suma-cero construida a partir de las teorías de von Neumann y Morgenstern (1953 sus propiedades básicas y algunos ejemplos elaborados a partir del lenguaje matemático, para explicar a la luz de las teorías de Nash (1950 las estrategias usadas por los jugadores en el contexto económico, militar y social. También, se presenta la noción de juego suma no-cero, no cooperativos entre dos personas, asumiendo la continuidad diferenciable de la función de pago. Finalmente, se explica a través de ejemplos construidos por los autores, los métodos de determinación del equilibrio de Nash puro y una metodología elemental para la determinación del equilibrio de Nash mixto.

  19. Equilibrio estratégico en economías con un continuo de agentes

    OpenAIRE

    Hervés Beloso, Carlos

    1998-01-01

    En este artículo, se considera una economía de intercambio puro con un continuo de agentes que pueden comportarse estratégicamente ocultando parte de sus recursos iniciales y falsificando sus verdaderas preferencias. Se introduce un concepto de equilibrio estratégico que permite considerar como caso particular otras nociones de equilibrio bien conocidas como, por ejemplo, el equilibrio Cournot-Walras. En este marco, se prueba que el comportamiento estratégico y el comportamiento precio-acepta...

  20. CRECIMIENTO, RELACIONES HÍDRICAS E INTERCAMBIO GASEOSO DE PLANTAS JÓVENES DE ILAMA (Annona diversifolia Saff. EN CONDICIONES DE ESTRÉS HÍDRICO

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    M. A. Otero-Sánchez

    2005-01-01

    Full Text Available Se estudiaron algunas características morfológicas y fisiológicas de Annona diversifolia Saff. con relación a condiciones de disponibilidad de agua del suelo. El nivel de humedad del suelo afectó el área foliar y la distribución de materia seca. El potencial hídrico de la hoja disminuyó a medida que se redujo el potencial hídrico del suelo, registrándose valores de -1.26, -1.51, 1.73, 1.76 y 2.36 MPa, en el testigo, sequía 1, sequía 2, sequía 3 y tratamiento sin riego, respectivamente. La tasa de intercambio gaseoso también fue reducida significativamente en los tres niveles de humedad del suelo. La concentración de prolina registró una correlación negativa con potencial osmótico, sin embargo, el análisis de regresión no presentó ninguna tendencia definida. Después de 10 días del riego de recuperación, se registró el restablecimiento casi completo de la tasa de intercambio gaseoso en los tratamientos de estrés moderado.

  1. Los diagramas de equilibrio de fases como una herramienta para el diseño y comprensión del comportamiento en servicio de los materiales refractarios

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    De Aza, A. H.

    2011-12-01

    Full Text Available Refractories are complex materials used at high temperature, in severely corrosive atmospheres and in contact with aggressive liquids. The high temperatures imply that such systems tend to equilibrium and this is frequently attained during service; at least local equilibrium is achieved. This allows the basic principles of phase diagrams to be used in this technology. Traditionally, refractories have been designed to be close to equilibrium so that in-service changes were restricted. Currently, additions of raw materials are often made that will react in use, in a controlled manner, to give favorable effects under the service conditions. Equilibrium diagrams are valid not only for determining the thermodynamic tendency but also for predicting the final equilibrium state and to know the way through which the material moves into the final state. In this context equilibrium diagrams become a powerful tool for a better understanding of the behavior of refractrories during service. After a general consideration on the importance of phase equilibrium diagrams in this field, criteria for using equilibrium diagrams, as a tool for improving traditional refractories and/or designing advanced or new refractories, will be given. Pertinent examples in different systems will be discussed. This paper compiles and reviews the last plenary lecture given by Professor Salvador De Aza on the subject.

    La aplicación de los diagramas de equilibrio de fases para diseñar materiales refractarios y también para comprender su comportamiento en servicio, ha sido, a lo largo del tiempo, un tema de controversia en el campo de la cerámica y de los refractarios. Sin embargo, en la tecnología refractaria moderna es posible obtener mezclas homogéneas a través de rutas sofisticadas de procesamiento. Como resultado, las velocidades de reacción son generalmente lo suficientemente altas para alcanzar el equilibrio o cuasi-equilibrio durante la cocción convencional

  2. EFICIENCIA Y EQUILIBRIO EN UN MODELO DE FORMACIÓN DE DERECHOS DE PROPIEDAD

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    José-María Da-Rocha

    2014-01-01

    Full Text Available En este artículo se presenta un modelo en que los agentes deben tomar decisiones acerca de la formalización de los derechos de propiedad sobre la tierra. En el modelo se muestra la existencia de un equilibrio en el que coexisten agentes que producen en tierras de libre acceso y agentes que producen en tierras de propiedad privada. Este equilibrio es ineficiente porque el esfuerzo para formalizar la tierra es menor de lo necesario.

  3. Equilibrio entre fases para la aplicación de solventes verdes en tecnología de alimentos

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    Hernández, Elvis J.

    2010-01-01

    [ES]: En este trabajo se presentan los resultados obtenidos del estudio (experimental y teórico) del equilibrio entre fases de compuestos alimentarios y solventes verdes, aportando nuevos resultados a los fundamentos de los procesos de separación por contacto en equilibrio de la tecnología de alimentos. Se obtuvieron nuevos datos de equilibrio entre fases, aplicando métodos experimentales a altas presiones (equilibrio líquido – fluido supercrítico, para el disolvente dióxido de carbono) y ...

  4. Importancia de los transmisores gaseosos CO y SH2 en la nefropatía diabética e isquémica

    OpenAIRE

    Perez Pardo, Cayetano

    2017-01-01

    A lo largo de los años, los conocimientos sobre papel representado por los transmisores gaseosos en los distintos procesos fisiológicos, y concretamente en la regulación de la función hemodinámica renal, ha crecido exponencialmente. Estos agentes son el óxido nítrico (NO), el monóxido de carbono (CO) y más recientemente el sulfuro de hidrógeno (SH2). El óxido nítrico (NO) es sintetizado a partir de la L-arginina, por una familia de enzimas llamadas genéricamente óxido nítrico sintasas (NO...

  5. La ambiguedad de la noción de equilibrio general con precio nulo del dinero

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    Carlo Benetti

    1995-07-01

    Full Text Available Al intentar demostrar la primacía la teoría de los precios relativos respecto a los monetarios, el pensamiento neoclásico moderno construye un modelo de economía monetaria agregando un bien especial en el modelo “real”. El precio de equilibrio de ese bien monetario es cero y de esta manera se afirma que una economía monetaria contiene un equilibrio que también pertenece a una economía sin dinero. EL presente ensayo argumenta que esta conclusión es errada y frustrante para la perspectiva neoclásica: un equilibrio económico con precio nulo del dinero lógicamente no existe

  6. Equilibrios químicos en bioadsorción

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    Romera, E.

    2007-02-01

    Full Text Available An experimental study of biosorption was carried out using six different kinds of algae and five different heavy metals (cadmium, copper, nickel, lead and zinc. Experimental data fitted very well to Langmuir’s model and this allowed to predict the behaviour of the biomass under specific working conditions. Using the equations of the model under different initial assumptions, a series of mathematical calculations were done for monometallic, bimetallic and trimetallic systems. The most complicated calculation is that in which, knowing the initial metal concentration (C0, it is necessary to calculate the conditions reached at the equilibrium, this is, qe and Ce. This assumption is of great interest from the point of view of the actual applicability of the process. However, in this case, it is necessary to solve very complex mathematical equations which, for multimetallic systems, are of degree n+1, where n is the number of ions present in solution.The excellent correlation between experimental and theoretical data demonstrates that the  biosorption process can be modelling.

    Se ha realizado un estudio experimental de bioadsorción utilizando seis tipos diferentes de algas y cinco metales pesados (cadmio, cobre, níquel, plomo y zinc. El buen ajuste de los datos experimentales al modelo de Langmuir ha permitido poder predecir el comportamiento de la biomasa en unas condiciones determinadas de trabajo. Todo ello, en base a una serie de cálculos matemáticos, utilizando las propias ecuaciones del modelo y bajo distintos supuestos iniciales de cálculo, tanto en sistemas monometálicos como en sistemas bimetálicos y trimetálicos. El supuesto de cálculo más complicado es el que, conociendo la concentración metálica inicial (C0 se deseen calcular las condiciones que se alcanzarían en el equilibrio, es decir, qe y Ce. Este, sería un supuesto de máximo interés de cara a

  7. Colin Rowe y el equilibrio dinámico

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    Pablo López Martín

    2015-05-01

    Full Text Available ResumenEn 1944 Gyorgy Kepes publica el que sin duda será su texto más influyente, El lenguaje de la visión. En él Kepes trata de llevar a cabo una guía que explique la gramática y la sintaxis del fenómeno de la visión, y que sirva como herramienta para enfrentarse al arte como experiencia puramente sensorial, desprovista de toda carga literaria, semántica o sentimental.De todos los conceptos que Kepes desgrana en su ensayo quizá el más determinante de todos sea el denominado como equilibrio dinámico y que aparece por primera vez en esta obra . Este término logra verbalizar algo que estaba en el aire, orbitando alrededor de toda la plástica moderna, pero que hasta el momento sólo había sido explicado de forma empírica.En Colin Rowe reverbera la lectura reciente de las ideas kepesianas cuando escribe sus artículos Transparencia literal y fenomenal y Neo-“clasicismo” y arquitectura moderna I y II tratando de poner en evidencia los principios fundacionales del movimiento moderno que negaban la dimensión plástica de la disciplina . El artículo tratará sacar de a la luz y explicar esta influencia. AbstractIn 1944 Gyorgy Kepes published what undoubtless will be his most influential text, "The language of vision". What Kepes tried to do was a guide of grammar and syntax of vision, which allows to face art as purely sensory experience or just visual, devisted of any literary , semantic or sentimental meaning.Among all the concepts that Kepes developes in his essay perhaps the most decisive one is the so called dynamic equilibrium, which is introduced in this work for fi rst time, verbalizing something that was in the air, orbiting around the entire modern plastic but far only explained in an empirical way.Colin Rowe reverberates the recent readed kepesian ideas on his own writings Transparency: Literal and Phenomenal and Neo-'Classicism' and Modern Architecture I and II, when the author tries to highlight the founding

  8. Estudio de los efectos del envejecimiento en la fuerza muscular y en el equilibrio

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    Barrena Aizcorbe, Oihane

    2011-01-01

    Objetivos: -Identificar cambios en la fuerza (máxima isométrica y explosiva) y en el equilibrio dinámico de las extremidades inferiores en las articulaciones de (caderas, rodilla y tobillo) entre los jóvenes y las personas mayores. -Determinar la relación existente la disminución de la fuerza a nivel de las extremidades inferiores y del equilibrio asociados a la edad. Material y métodos: Se ha realizado un estudio descriptivo transversal para determinar la fuerza máxima isométrica y explosiva...

  9. El equilibrio químico : una investigación de aula

    OpenAIRE

    Huerta Ruíz, María Patricia

    2008-01-01

    Se presenta una metodología didáctica para promover el aprendizaje del equilibrio químico. El punto de inicio es la identificación y construcción de las características del concepto, con base en el uso de analogías, resolución de problemas y trabajos prácticos y se sugiere no introducir el Principio de LeChatelier antes de trabajar suficientemente los conceptos de equilibrio dinámico e irreversibilidad de reacciones. La propuesta se probó con alumnos del último año del bachillerato de la UNAM...

  10. ENTRE EL EQUILIBRIO Y LA INESTABILIDAD. EL MONOCICLO COMO RECURSO ESCULTÓRICO

    OpenAIRE

    MOYA MARTINEZ, SERGIO

    2018-01-01

    El trabajo aborda la idea del equilibrio utilizando el monociclo como recurso ya que es un objeto que representa el concepto del equilibrio de una forma explícita. El proyecto es un conjunto de obras escultóricas que dan solución a esta inquietud artística que nos planteamos en las cuales queremos plasmar esa sensación con la que trabajamos. The work addresses the idea of ¿¿equilibrium using the unicycle as a resource since it is an object that represents the concept of equilibrium in an e...

  11. Intercambio gaseoso en el síndrome de dificultad respiratoria aguda Gas exchange in acute respiratory distress syndrome

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    G. A. Raimondi

    2003-04-01

    Full Text Available El síndrome de dificultad respiratoria aguda (ARDS se caracteriza por presentar alteraciones severas del intercambio gaseoso (IG causadas por «shunt» e importante irregularidad de la ventilación perfusión (V A/Q. Esto es consecuencia del edema intersticial y el colapso y ocupación alveolar. Además de la fracción inspirada de oxígeno y la evolución de la patología pulmonar, hay distintas variables que son capaces de alterar la presión parcial de oxígeno arterial (PaO2. Es así que los cambios del volumen minuto circulatorio, la concentración de hemoglobina, el consumo de oxígeno o la alcalosis pueden modificar la PaO2 a través de su influencia en la PO2 de sangre venosa mixta. A pesar de la influencia de estas diferentes variables, la anormalidad del IG se ha podido analizar adecuadamente por medio de la técnica de eliminación de múltiples gases inertes (MIGET. Asimismo, se han descripto diversas estrategias ventilatorias (presión positiva de fin de espiración, relaciones inspiratorias-espiratorias invertidas, volúmenes corrientes elevados, etc. que producen mejoría del IG principalmente a través del aumento de la presión media en la vía aérea al reclutar áreas pulmonares previamente colapsadas. También el cambio de decúbito a posición ventral, por modificaciones en la distribución de presión pleural regional, disminuye el colapso alveolar con mejoría de la PaO2. Asimismo hay distintas intervenciones farmacológicas capaces de mejorar el IG tales como la administración de óxido nítrico (ON o de prostaglandinas (PGI2 o PGE1 por vía inhalatoria. Estas producen vasodilatación de las áreas bien ventiladas aumentando el flujo cardíaco a ese nivel y disminuyendo relativamente el flujo por las áreas de «shunt». La almitrina endovenosa, droga vasoconstrictora pulmonar, mejora el IG al aumentar la vasoconstricción hipóxica. Se ha demostrado efecto aditivo de la almitrina con la inhalación de ON. A pesar del

  12. Equilibrios químicos en disolución. Equilibrios concurrentes: efecto del pH en la solubilidad. Estudio del carbonato de calcio.

    OpenAIRE

    Milla González, Miguel

    2016-01-01

    En este ejercicio se trata de encontrar el valor del pH del sistema heterogéneo carbonato de calcio sólido-calcio en disolución de forma que una concentración de calcio 10-5 molar se halle en equilibrio con una concentración total de carbonato en disolución igual a 0.1 molar. En otras palabras, hay que calcular la concentración de protones que haga compatible una concentración 10-5 molar de calcio con una concentración de todas las formas del carbónico igual a 0.1 molar, en equilibrio con car...

  13. Efectos del entrenamiento en superficies inestables sobre el equilibrio y funcionalidad en adultos mayores

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    Juan C. López S

    2015-02-01

    Full Text Available Objetivo: determinar los efectos de un programa de ocho semanas de entrenamiento en superficies inestables con y sin trabajo de fuerza, sobre el equilibrio y la capacidad funcional en adultos mayores de 60 años, pertenecientes al programa “Escuelas populares del deporte” del inder Medellín. Metodología: se llevó a cabo un estudio experimental simple, ciego y enmascarado con asignación al azar de 34 sujetos a dos grupos de intervención con y sin trabajo de fuerza sobre superficies inestables; se midió el equilibrio unipodal, bipodal con ojos abiertos y cerrados, además de pruebas funcionales como Up and Go, arm curl y chair test. Resultados: las intervenciones con y sin trabajo de fuerza mejoraron el equilibrio total en 57,0 y 69,5 segundos respectivamente, sin diferencias estadísticamente significativas en la comparación entre los grupos (p = 0,13. Se mejoró la velocidad de la marcha con ambas intervenciones sin diferencias intragrupos estadísticamente significativas (p = 0,33 pero importantes para la práctica. Conclusión: ambas intervenciones mejoran el equilibrio, sin embargo existen diferencias importantes para la práctica a favor del programa sobre superficies inestables sin trabajo de fuerza, pues la intervención tiene un mejor efecto sobre el equilibrio unipodal y bipodal tanto con ojos abiertos como con cerrados.

  14. Determinación de la secuencia de precipitación salina en la laguna de La Playa (Zaragoza, España. 1. Condiciones de equilibrio mineral y simulación teórica del proceso

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    Gómez, J.

    1999-04-01

    Full Text Available Neutral brines of the Na-Cl type from La Playa saline system reach extremely high concentrations (up to ionic strengths of 10 molal during the evaporative process. Ionic activities and mineral saturation indices in waters sampled along their evaporative path are calculated by PHRQPITZ code to study their geochemical evolution. Saturation states calculated by the code have pointed out that al! brines sampled were saturated with respect to calcite, gypsum and anhydrite. However, their stability diagram shows that water activity values determine gypsum to be the more stable phase in the Ca-S04-H20 system for almost all samples. Halite, thenardite and bloedite reach saturation at a late stage during brine evolution. The evolving paths of mirabilite, glauberite, polyhalite and epsomite do not show any evidence of brine-mineral equilibrium process along evaporative evolution. Nevertheless, mirabilite saturation state should be taken with caution because of the lack of field temperature data. Calculations carried out at 15° C shows that mirabilite is affected by reequilibrium processes which take place at short temporal scales (daily fluctuations of temperature. The comparison of these results with those of Garcés et al. (1991, 1992 indicates that Pitzer' s formulation is the more adequate approach for the physicochemical treatment of highly concentrated waters. Theoretical simulation of evaporation process has been carried out using the most diluted sample like starting point. Open system in relation to gaseous exchange between brine and atmosphere, and constant temperature (25° C have been considered like boundary conditions along the calculations. Simulation results have faithfully reproduced the evolving path defined by means of physicochemical treatment of brine samples. This supports the previously posed hypothesis in relation to the sequence of mineral precipitation that should take place in the saline system. Moreover, this fact suggests

  15. El dinero en modelos de equilibrio general sobre la no-neutralidad del dinero, una nota introductoria

    OpenAIRE

    Garay S. Jose Luis

    1990-01-01

    Sólo en la medida en que el dinero sea concebido dentro de un esquema de equilibrio general; es posible llegar a comprender en su integridad, tanto las funciones como la naturaleza misma de la moneda. De otra manera, si se incorpora «desde afuera" el dinero en modelos en los que se supone la existencia de un equilibrio, independientemente de la mediación del dinero es decir, un equilibrio de trueque, que posteriormente es especificado en unidades monetarias, mediante la introducción artificia...

  16. MÉTODOS PARA CARACTERIZAR COMBUSTIBLES LÍQUIDOS Y GASEOSOS OBTENIDOS DE LLANTAS EN DESUSO A TRAVÉS DE LAS NORMAS ASTM.

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    JAIME ALEJANDRO OSPINA

    2011-12-01

    Full Text Available Este artículo muestra la importancia de la caracterización de la energía de combustibles líquidos y gaseosos obtenidos del conocido tratamiento térmico de pirolisis a través de un microondas. La caracterización de estos combustibles tomará en cuenta los estándares técnicos tales como ASTM D3452 – 93 para la cromatografía de gases (GC, ASTM D2549 para cromatografía de gas/ espectrometría de masa (GC/MS y ASTM D6370 -99 para termogravimetría en el análisis de la composición de llantas.También muestra que estos combustibles y gases de pirolisis tiene una alta valor calorífico de 42 MJ / Kg y un contenido de azufre entre 0.8 y 1.65 Wt%, dependiendo en el tipo de llanta y las condiciones del proceso.

  17. Obtención del punto de equilibrio de reacciones en fase gaseosa

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    M. Ewerts S.

    2009-05-01

    Full Text Available Castellan (Physical Chenaistry, la ed, . p 214 indica un método gráfico para hallar la coordenada de reacción a partir de los potenciales químicos Lt(T,P para una reacción en fase gaseosa. El método, que posiblemente se presta bien al estudio de equilibrios simples, esincómodo cuando se quiere aplicar por ejemplo a la reacción.

  18. Obtención del punto de equilibrio de reacciones en fase gaseosa

    OpenAIRE

    Ewerts S., M.

    2009-01-01

    Castellan (Physical Chenaistry, la ed, . p 214) indica un método gráfico para hallar la coordenada de reacción a partir de los potenciales químicos Lt(T,P) para una reacción en fase gaseosa. El método, que posiblemente se presta bien al estudio de equilibrios simples, esincómodo cuando se quiere aplicar por ejemplo a la reacción.

  19. EQUILIBRIO ECONÓMICO Y LA CONTRATACIÓN PÚBLICA EN COLOMBIA

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    Yuri Gorbaneff

    2009-01-01

    Full Text Available La contratación pública en Colombia es conflictiva, poco eficaz y eficiente; con frecuencia le causa daño patrimonial al Estado. El sistema legal colombiano no fue capaz de hacer eficiente ni transparente la contratación pública, que transcurre en un ambiente institucional caracterizado por los altos costos de transacción. La ley colombiana complica las cosas aun más con el principio del equilibrio económico de los contratos, que aumenta la contratación incompleta y dificulta el uso de los incentivos económicos para controlar el oportunismo de los agentes económicos. Los autores formulan la hipótesis de que el principio del equilibrio económico contribuye a aumentar la litigación en la contratación pública. Se hace la prueba empírica de la hipótesis. En la primera sección se hace el resumen de la literatura económica sobre los costos de transacción y el contrato incompleto, así como la literatura jurídica sobre el origen histórico del principio del equilibrio económico de lo contratos. La segunda sección describe la metodología del estudio empírico. La tercera presenta la evidencia empírica de los efectos que ejerce el principio del equilibrio sobre la contratación pública. Siguen las conclusiones.

  20. Ideología y matemáticas: Equilibrio y tiempo

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    Llorente Marrón, Mª del Mar

    2001-01-01

    Full Text Available En esta comunicación se recogen distintas definiciones del concepto de equilibrio económico, y las opiniones de distintos autores partidarios de que el concepto de equilibrio se defina en un contexto dinámico. De otro modo no tendría sentido caracterizar el equilibrio como un estado de reposo, ya que todo cambio, movimiento o fluctuación ocurre en el tiempo. Posteriormente, se estudian distintas propuestas para formular modelos económicos dinámicos. Se defiende la necesidad de un análisis en profundidad, para el cual la Matemática proporciona un instrumento imprescindible: las funciones compuestas. En este análisis el elemento tiempo debe aparecer, de forma explícita, como única variable exógena, esto es, como soporte y causa última de cualquier cambio o evolución. Este planteamiento implica la revisión de hipótesis y supuestos generalmente admitidos en el Análisis Económico estático. Respecto a la docencia de las Matemáticas, será preciso introducir en nuestro programas aspectos que permitan estudiar unas Matemáticas para el Desequilibrio Económico.

  1. Estudio del equilibrio débil en un modelo discreto del juego de downs

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    Rodrigo, J.

    2006-01-01

    Full Text Available En los modelos tradicionales de competición política entre dos partidos, como son el juego de Downs y el de Wittman, el estudio de las posiciones de equilibrio arroja un resultado poco viable en la práctica, que es que el equilibrio, si existe, se produce usualmente cuando los dos partidos eligen la misma posición, es decir, con los dos partidos llevando a cabo la misma política. En este trabajo se propone una versión discreta del juego de Downs, y una debilitación de la definición clásica de equilibrio, que hace que éste no sea único, sino que se alcanza en ciertas regiones que hay que determinar utilizando técnicas de la geometría computacional. Esto da posiciones “casi de equilibrio” en las que los partidos no tienen necesariamente que tomar la misma posición (política.

  2. Impacto de la maniobra de inspiración profunda en el intercambio gaseoso del sujeto con obesidad severa e hipertensión arterial pulmonar asociada a síndrome de Eisenmenger

    OpenAIRE

    Santos-Martínez,Luis-Efren; Martínez-Guerra,María-Luisa; Bautista,Edgar; Castillo,Francisco; Castañón,Alicia; Pulido,Tomás; Hernández,José-Luis; Sandoval,Julio

    2008-01-01

    La obesidad y el síndrome de Eisenmenger son entidades ampliamente estudiadas. Sin embargo, su asociación es inusual y no informada. Ambas cursan con alteraciones del intercambio gaseoso de grado variable. En la obesidad severa son atribuidas a trastornos en la relación ventilación/perfusión y al cortocircuito venoarterial pulmonar que dependen del volumen pulmonar. En el síndrome de Eisenmenger con obesidad severa, esta dependencia se desconoce. Material y métodos: Se estudiaron 28 sujetos o...

  3. Study of the absorbed dose in small fields with absence of lateral electronic balance in stereotactic radiosurgery and radiotherapy with modulated intensity; Estudio de la dosis absorbida en campos pequenos con ausencia de equilibrio electronico lateral en radiocirugia estereotaxica y radioterapia con intensidad modulada

    Energy Technology Data Exchange (ETDEWEB)

    Vargas V, M. X.

    2013-07-01

    In this thesis we develop and experimental and theoretical study, using semi analytical techniques of the physical dosimetry for small and nonstandard fields for stereotactic radiosurgery (Srs) and intensity modulated radiation therapy (IMRT), with high energy photon beams from a BrainLAB system with cones at Instituto del Cancer SOLCA (Ecuador) and a Tomo Therapy Hi-Art system at Centro Oncologico de Chihuahua (Mexico). (Author)

  4. El turismo cultural: gestión de partes interesadas y la complejidad del equilibrio

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    Alfredo Ascanio

    2009-01-01

    Full Text Available El equilibrio del desarrollo sostenible es posible siempre que las partes interesadas colaboren entre sí. Durante 1999 comenzó el desarrollo de un modelo normativo de planificación turística basado en la coordinación de los intereses de los actores del turismo. Esta herramienta lograría equilibrar los intereses de las partes implicadas y sus servicios. Ello supone implantar una estrategia de segmentación, como fue sugerido por los expertos en marketing turístico Elise Truly Sautter y Birgit Leisen.

  5. Necesita Explicar el Equilibrio Termodinámico? Simúlelo!

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    Mauricio García Castañeda

    1990-01-01

    El ánimo de la presente comunicación es mostrar como empleando una rutina numérica simple, (que puede ser implementada en una calculadora programable, se simula la evolución de un sistema físico hacia un estado de equilibrio termodinámico, cuando el estado inicial del sistema se prepara arbitrariamente, permitiéndose que se den intercambios elásticos de energía entre pares de partículas en el sistema de una manera total mente al azar.

  6. Los modelos de equilibrio general estocástico y el tipo de cambio

    OpenAIRE

    Jiménez Martín, Juan Ángel

    2003-01-01

    Una parte muy importante de la investigación en economía financiera inernacional se ha dedicado a explicar el comportamiento del tipo de cambio. A partir de los años 80, Lucas (1978,1982), Helpman y Razin (1979,1982) y Stockman (1980,1983,1987) implementan los modelos de equilibrio dinámicos como herramienta para analizar teóricamente algunos de los problemas más relevantes que se estaban produciendo en los mercados de divisas, sobre todo, los relacionados con los posibles efectos de la polít...

  7. Agrupación y equilibrio competitivo en el baloncesto profesional NBA y ACB

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    Yves de Saá Guerra

    2016-06-01

    Full Text Available Algunas ligas de baloncesto son más competidas que otras. El nivel de incertidumbre en la clasificación final está estrechamente relacionado con el atractivo en la liga. La efectividad de un equipo tiene una relación recíproca con el ambiente emergente y crítico: la competición. Los equipos se ven afectados por el entorno que les rodea. El modelo competitivo influencia directamente sobre la competición, de esta manera pequeños cambios pueden alterar dramáticamente el resultado final. Hemos comparado dos modelos deportivos diferentes para averiguar el nivel de jerarquía de estas competiciones. Hemos estudiado los resultados de dos ligas profesionales de baloncesto: 18 temporadas de la NBA (USA y 14 de la ACB (España. Observamos que los equipos ACB se encuentran en tres niveles de rendimiento (ratio 0,15 ± 0,05; 0,45 ± 0,15; 0,8 ± 0,1. Pero los datos de la NBA son menos dispersos y más gaussianos (ratio pico 0,5. Un análisis general (Entropía de Shannon muestra que el equilibrio competitivo no permanece estable (Sn NBA media = 0,9842 ± 0,0037; Sn ACB media = 0,9793 ± 0,0053. Un estudio más detallado (análisis de clúster muestra que en la ACB hay equipos claramente enraizados en un área particular de la competición. La mayoría de los equipos de la NBA han alcanzado los playoffs. No existe un consenso para el estudio de equilibrio competitivo. Proponemos el uso de varias metodologías con el fin de averiguar el grado de competitividad de una liga determinada. El modelo deportivo influencia altamente en los niveles de equilibrio competitivo. Tanto la ACB y la NBA presentan un alto equilibrio competitivo. La NBA tiene mecanismos específicos para asegurar la alta competitividad y la ACB no cumple con la ausencia de dominación a largo plazo.

  8. Revisión de las repercusiones de los esguinces de tobillo sobre el equilibrio postural

    OpenAIRE

    Martín Casado, Laura; Aguado Jódar, Xavier

    2011-01-01

    El esguince lateral de tobillo es una de las lesiones más comunes ocurridas en deporte, pudiendo afectar a diferentes componentes del control postural. Esta revisión bibliográfica analiza los estudios en los que se evalúa el control postural a partir de tests de equilibrio estático, dinámico y dinámico funcional en personas que han sufrido un esguince y personas con tobillos sanos utilizando metodologías cuantitativas. Los tobillos lesionados presentan mayores rangos de desplazamiento d...

  9. Aportaciones sobre la eficacia del método Pilates en la fuerza, el equilibrio y el riesgo de caídas de personas mayores

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    D. Reche-Orenes

    2016-06-01

    Conclusiones: El método Pilates es eficaz para mejorar la fuerza isométrica de cadera y el equilibrio en personas mayores, reduciendo el riesgo de caídas. No existen evidencias suficientes para determinar si la fuerza del core tiene que ver con el equilibrio y las caídas.

  10. ¿El equilibrio en desequilibrio? La ley de Say y la igualdad de tasas de ganancia

    OpenAIRE

    Ramírez, Jaime David

    2008-01-01

    En este ensayo se pretende establecer la relación entre Ley de Say y el equilibrio clásico de igualdad de tasas de ganancias. Primero se define el equilibrio clásico dentro de una economía e igualmente se da una versión de la Ley de Say. Posteriormente, se esclarece la relación de estos dos conceptos en una economía. Se concluye que la relación es de equivalencia.

  11. Dificultades conceptuales para predecir equilibrios químicos homogéneos y heterogéneos

    OpenAIRE

    López González, W.

    2009-01-01

    En este trabajo quedan evidenciados los errores conceptuales en una muestra a la que se aplicó un instrumento, en el que se le planteó distintas situaciones para predecir el desplazamiento de un sistema en equilibrio. Se presentaron dificultades aplicando el principio de LeChatelier en cuanto a: comparaciones masa-concentración, inyección de un gas inerte al sistema, a volumen (V) y temperatura (T) constantes, inyección de uno de los gases intervinientes en el equilibrio a presión (P) y T con...

  12. Análisis del riesgo de caídas en ancianos institucionalizados mediante escalas de marcha y equilibrio

    OpenAIRE

    Martínez Carrasco, Ángel

    2016-01-01

    Introducción: Las caídas en la población mayor son un problema con graves consecuencias personales y elevados costes sociosanitarios. Las alteraciones del equilibrio se consideran riesgo de caídas en esta población. Objetivos: Determinar las pruebas de equilibrio más precisas para predecir el riesgo de sufrir caídas, cuantificar las caídas producidas durante doce meses de seguimiento y describir la incidencia y los factores de riesgo de caídas en personas que viven en residencias de mayo...

  13. EQUILIBRIO DE FASES PARA SISTEMAS ETANOL-AGUA EN PRESENCIA DE POLIALCOHOLES Y SALES

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    LUIS RIOS

    2011-01-01

    Full Text Available Se propone un modelo termodinámico semiempírico para el equilibrio líquidovapor del sistema etanolagua con polialcoholes y sales. El modelo usa las ecuaciones GibbsDuhem y DebyeHückel, las cuales modifican el modelo UNIQUACE. Se consideran las fuertes interacciones químicas asociadas a los fenómenos de solvatación e hidratación de iones, y el concepto de solvatación del modelo de Ohe. Se tienen en cuenta las interacciones de corto alcance, dadas por las fuerzas de van der Waals, y las interacciones de largo alcanceconsideradas en el término de DebyeHückel. Se determinaron los parámetros empíricos de ajuste para los sistemas etanolaguapolialcoholcloruro de calcio y acetato de potasio; estos sistemas son de interés industrial debido a que la adición de polialcohol y sal mejora la eficiencia de la separación.. Las mediciones isobáricas del equilibrio líquidovapor se realizaron en un destilador Othmer. Este modelo termodinámico sería útil para diseñar y simular columnas para destilación extractiva aguaetanol.

  14. Problemas asociados al equilibrio en estructuras de membrana con bordes rígidos y cables

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    Viglialoro, G.

    2011-12-01

    Full Text Available This paper presents the equilibrium analysis of a membrane with rigid and cable boundaries for the so called prestressing phase. The idea of using membranes in Civil Engineering applications such as footbridges, a new technology being developed in Spain, implies higher structural responsibility and more accurate analysis procedure. The membrane and its boundary are respectively identified to a regular and negative gaussian curvature surface and a set of regular curves whose curvature depends on the structural elements, rigid or cable. Equilibrium is directly expressed by means of boundary differential problems, in terms of the membrane shape and its stress tensor. We must outline that membrane-cable interface equilibrium leads to take into account a singular condition that makes the problem more difficult. Therefore, starting from the equilibrium equations, two dual problems can be considered namely direct problem and dual problem. Both problems will be defined and analyzed, studying their principal qualitative aspects. Particularly, for the direct problem a numerical resolution procedure is proposed, in order to obtain practical results.

    Este trabajo aborda el análisis del equilibrio de una membrana con bordes rígidos y cables de borde para la fase de pretensado. La idea de utilizar las membranas en aplicaciones como las pasarelas, una nueva tecnología que está siendo desarrollada en España, implica niveles más altos de responsabilidad y de esfuerzos, requiriendo así un anáisis estructural ajustado. La membrana y sus bordes se identifican, respectivamente, a una superficie con curvatura de Gauss negativa y a curvas cuya curvatura depende de las características estructurales de los bordes. El equilibrio se expresa mediante problemas de contorno con ecuaciones en derivadas parciales, en términos de la forma de la membrana y de su tensor de esfuerzos, así como de la forma y las cargas de los bordes. En particular, el equilibrio

  15. A gaseous scintillation counter filled with He{sup 3} for neutron spectrometry; Compteur a scintillateur gazeux rempli de {sup 3}He pour la spectrometrie des flux de neutrons; Gazovyj stsintillyatsionnyj schetchik napolnennyj He{sup 3} dlya spektrometrii potokov nejtronov; Contador de centelleador gaseoso cargado con helio-3 para la espectrometria neutronica

    Energy Technology Data Exchange (ETDEWEB)

    Baldin, S A; Matveev, V V

    1962-04-15

    The paper describes a gas plant and gaseous scintillation counter, and gives the results of experiments on the recording and spectrometry of neutron beams using a gaseous scintillation counter filled with a mixture of 10% xenene and 90% helium-3 at an overall pressure of 20 ata. Data are given on the design of the gas plant, which makes it possible to operate the counter continuously over long periods of time, as well as providing the required gas mixtures at overall pressures of up to 60 atm and ensuring constant freedom of the gas from contamination. In addition, the paper presents the results of research on the counter's energy resolution and linearity at different energy levels and indicates its efficiency in gamma fields of intensity up to 3 r/h; the possibility of extending the working energy-range of gaseous scintillation counters filled with helium-3 is also considered. (author) [French] FLes auteurs decrivent un compteur a scintillateur gazeux ainsi que les resultats des experiences d'enregistrement et de spectrometrie des flux de neutrons qui ont ete faites au moyen d'un compteur a scintillateur gazeux rempli d'un melange de 10% de xenon et de 90% d'helium-3 sous une pression de 20 atmospheres. Ils exposent les donnees relatives a la construction d'un appareillage qui assure le fonctionnement ininterrompu du compteur durant un laps de temps prolonge, l'obtention des melanges de gaz indispensables sous une pression totale de 60 atmospheres et l'epuration continue du gaz. En outre, ils examinent les resultats de l'etude du pouvoir de resolution en energie et de la linearite du compteur en fonction de l'energie, le fonctionnement du compteur dans les champs de rayonnement gamma d'une intensite allant jusqu'a 3 r/h, ainsi que la possibilite d'elargir la gamme d'energie dans laquelle on peut employer des compteurs a scintillateurs gazeux de {sup 3}He. (author) [Spanish] En esta memoria se describe un aparato de suministro de gas y un contador de centelleador

  16. Terapia acuática en alteraciones de equilibrio de origen neurológico

    OpenAIRE

    Álvaro Macarrilla, Nagore

    2014-01-01

    RESUMEN: Objetivo: El objetivo de este trabajo, es realizar una revisión de la literatura actual sobre la efectividad de la Terapia Acuática (TA) en el tratamiento rehabilitador de las patologías neurológicas que cursan con una alteración del equilibrio estático y/o dinámico. Material y métodos: Para la elaboración de esta revisión se ha efectuado una búsqueda exhaustiva de las principales bases de datos de ciencias de la salud (PubMed, PEDro, ScienceDirect, Cochrane y LILACS). El principal p...

  17. Y TRANSFERENCIAS EN MÉXICO. Un análisis de equilibrio general aplicado

    Directory of Open Access Journals (Sweden)

    Enrique R. Casares

    2015-01-01

    Full Text Available En este artículo se argumenta que, dada la fuerte concentración del ingreso en México y la estrechez de la base tributaria del ingreso, resulta muy difícil realizar una reforma tributaria que sea recaudatoria y redistributiva. Para ello se construyó un modelo de equilibrio general aplicado que incluye, entre otras cosas, una desagregación de los hogares en 10 niveles de ingreso, la estructura tributaria y de transferencias del país y las esferas productivas y de consumo. Los escenarios confirman que, lograr una recaudación adicional significativa, y mejorar al mismo tiempo la desigualdad del ingreso (medida por el coeficiente de Gini, implica aumentos de tasas o bases difíciles de lograr en las condiciones actuales.

  18. Profesores con vocación de excelencia (en búsqueda del equilibrio)

    OpenAIRE

    Ramírez-Carvajal, Diana Maria

    2016-01-01

    En él se abordan reflexiones sobre los objetivos más loables de la educación superior, éstos sin dudas los cuales son parte del día a día del profesor universitario. El equilibrio en las funciones misionales, la ética que se traslada al estudiante, la cada vez más fuerte intermediación de las TIC en la labor educativa y el aprendizaje basado en competencias —un giro de complejidad a la labor educativa—, entre otros, llevan al docente a ser núcleo de la calidad de la educación superior, de lo ...

  19. SIMULACIÓN DE UN MODELO DE EQUILIBRIO GENERAL COMPUTABLE PARA VENEZUELA

    Directory of Open Access Journals (Sweden)

    Luis Enrique Pedauga

    2012-01-01

    Full Text Available Este artículo presenta los resultados de la simulación de un modelo de equilibrio general computable construido para Venezuela. El uso de este modelo se ejempli-fica mediante la calibración y simulación de una economía abierta con tres agentes institucionales (hogares, empresas y gobierno y tres sectores productivos (petró-leo, manufactura y resto, para una economía abierta. Se considera diferentes re-glas de política. En cada caso se muestra el proceso de calibración y los resultados de las simulaciones utilizando información proveniente de la serie de matrices de contabilidad social para Venezuela entre 1997 y 2005. Se aporta simulaciones de la economía hasta 2009, tanto en los parámetros pertinentes y como algunos ejerci-cios de sensibilidad

  20. Poblaciones de los niveles atómicos en condiciones de no equilibrio

    Science.gov (United States)

    Cruzado, A.

    El objetivo de este trabajo es encontrar la distribución de los átomos en los diferentes niveles de energía. Con el propósito de encontrar resultados generales y de amplia aplicación, hemos planteado las ecuaciones de equilibrio estadístico como función del número atómico del elemento a considerar y de las condiciones físicas del medio (temperatura y densidad). Así también se ha intentado tener en cuenta todos los niveles atómicos considerando explícitamente aquellos con un número cuántico principal menor que un cierto valor n y calculando una expresión aproximada para estimar la influencia de los demás.

  1. Equilibrio liquido-liquido-vapor de misturas ternarias : algoritimo de calculo e aspectos termodinamicos

    OpenAIRE

    Maria Helena Cano de Andrade

    1991-01-01

    Resumo: Este trabalho é uma contribuição ao estudo de processos de separação envolvendo fases em equilibrio liquido-liquido-vapor. Os seguintes aspectos são abordados: (1) desenvolvimento de um algoritmo eficiente de cálculo de flash liquido-liquido-vapor e sua aplicação para gerar diagramas de fases e em cálculos de destilação; (2) avaliação da utilização de parâmetros binários do modelo UNIQUAC obtidos de dados bifásicos em cálculos trifásicos de misturas ternárias; (3) medidas experimentai...

  2. Problemas asociados al equilibrio en estructuras de membrana con bordes rígidos

    Directory of Open Access Journals (Sweden)

    Martínez, F.

    2009-12-01

    Full Text Available This paper presents the equilibrium analysis of a membrane with rigid boundary. The idea of using membranes in applications such as footbridges, a new technology being developed in Spain, implies a more accurate analysis procedure. Due to the tension stresses, membrane is identifi ed to a negative gaussian curvature surface. Equilibrium is directly expressed by means of partial differential equations, in terms of the membrane shape and stress tensor. Starting from these equations, two dual approaches can be defi ned, namely direct problem and dual problem. Both problems are analyzed, studying their possible solutions in order to obtain practical results. In particular, the main analytical aspects of the direct problem are discussed, a numerical resolution procedure is proposed and, fi nally, analytical and numerical solution examples are presented.Este trabajo aborda el análisis del equilibrio de una membrana con borde rígido. La idea de utilizar las membranas en aplicaciones tales como las pasarelas, una nueva tecnología que se está desarrollando en España, requiere un análisis estructural muy ajustado. Debido a los esfuerzos de tracción, la membrana se identifi ca a una superficie con curvatura de Gauss negativa. De esta forma, el equilibrio se expresa directamente por medio de ecuaciones diferenciales en derivadas parciales, en términos de la forma de la membrana y del tensor de esfuerzos. A partir de dichas ecuaciones, se pueden considerar dos enfoques complementarios, aquí llamados problema directo y problema dual. Se analizan ambos problemas, estudiando sus posibles soluciones con el objetivo de obtener resultados prácticos. En particular, se profundizan los principales aspectos analíticos del problema directo, se propone un método numérico para la resolución y, fi nalmente, se presentan ejemplos de solución analítica y numérica.

  3. El análisis económico del derecho de autor y del copyright, un estudio del equilibrio entre los intereses público y privado

    OpenAIRE

    Ana María Pérez Gómez Tétrel

    2007-01-01

    La propiedad intelectual ha sido concebida para responder, tanto a la necesidad de protección del autor de una obra del intelecto, como al beneficio que la sociedad pueda sacar del acceso a dichas creaciones intelectuales, generando así un equilibrio entre los diferentes actores. Los sistemas digitales de comunicación han puesto en jaque dicho equilibrio. Conviene preguntarse ¿es capaz la protección otorgada por el derecho a la creación intelectual, de establecer un equilibrio en las relacion...

  4. Intervenciones basadas en realidad virtual para el entrenamiento de las estrategias de equilibrio en sujetos crónicos con daño cerebral adquirido

    OpenAIRE

    Lloréns Rodríguez, Roberto

    2014-01-01

    El equilibrio se define como el estado en el cual el centro de gravedad (CDG) del cuerpo se encuentra dentro de los límites de estabilidad. La gestión del equilibrio es un claro ejemplo del control motor humano, donde la información sensorial es procesada por el sistema nervioso central para generar la actividad muscular adecuada para producir los mecanismos de anticipación y/o compensación que preserven este estado. El equilibrio tiene una gran implicación en las actividades de la vida diari...

  5. Estudio geométrico del equilibrio en un modelo discreto del juego de downs

    Directory of Open Access Journals (Sweden)

    Javier Rodrigo

    2005-01-01

    Full Text Available Este trabajo profundiza en el estudio de un juego competitivo que puede ser interpretado como una versión discreta del juego de Voronoi tratado en Geometría Computacional y del modelo de Downs de Economía Política. Dados dos partidos políticos cuyas posiciones vienen dadas por las políticas ofrecidas y un conjunto finito de votantes cuyas posiciones vienen dadas por sus tipos, ganará el partido que consiga mayor número de votantes, es decir, que tenga mayor número de votantes más cercanos a su opción política que a la del otro. No se considerarán restricciones en las posiciones de los partidos. Estudiaremos las distintas estrategias que existen para que un partido gane considerando par o impar el número de votantes. Por último, obtendremos condiciones que tendrán que cumplir las posibles posiciones de equilibrio del juego. Por el planteamiento y características de este juego vamos a utilizar técnicas de Geometría Computacional.

  6. EQUILIBRIO HIDRÁULICO EN SISTEMAS DE BOMBEO MINERO: ESTUDIO DE CASO HYDRAULIC BALANCE ON MINE PUMPING SYSTEMS: A CASE STUDY

    Directory of Open Access Journals (Sweden)

    Luis Enrique Ortiz Vidal

    2010-12-01

    Full Text Available Fue evaluada la influencia del uso de los métodos de Hazen-Williams y Darcy-Weisbach en el establecimiento del equilibrio hidráulico para un sistema de bombeo minero. Empresas mineras con actividad subterránea hacen uso de estaciones de bombeo para evacuar el agua, producto de la profundización de sus labores. Proyectistas y vendedores de equipos de bombeo usan diferentes expresiones para la estimación de la pérdida de carga total del sistema, parámetro importante para la determinación del equilibrio hidráulico. El presente estudio tiene como objetivo analizar y validar la aplicación de algunas de estas expresiones para un sistema de bombeo minero. Las principales características del estudio de caso son: caudal de agua de 1.350 l/s; tuberías de acero y HDPE de 16 in y 18 in de diámetro, respectivamente; longitud total de la tubería de 2.900 m; y una altura geodésica de 230 m. Los cálculos fueron realizados con los métodos ya mencionados teniendo las expresiones de Haaland, Swamee-Jain y Churchill como factores de fricción. Los resultados obtenidos fueron comparados con los medidos en campo, teniéndose una desviación máxima del sistema de 28,6% y 3,1% para la pérdida de carga y Hman total, respectivamente.This study evaluates the influence of the Hazen-Williams and Darcy-Weisbach methods on the hydraulic balance of a mine pumping system. Underground mining sompanies use pumping stations for evacuate the produced water. Designers and equipment sellers use different expressions to estimate the head loss. This study analyzes and validates the implementation of some of these expressions to a mine pumping system. The features of the case study are: water flow rate of 1350 l/s, steel and HDPE diameter pipes of 16in. and 18in., respectively. The total pipe length is 2900m, and the hydraulic height difference is 230 m. The calculations were performed by the above-mention methods, taking the expressions of Haaland, Swamee-Jain and

  7. Cuidado de sí mismo, equilibrio y perfil de aprendizaje del IB

    Directory of Open Access Journals (Sweden)

    Matthew Allen

    2013-12-01

    Full Text Available La evidencia anecdótica sugiere que los educadores tienden a dedicarse por completo a sus estudiantes y no tanto a sí mismos, lo que a menudo conduce a un estrés excesivo, a enfermedades relacionadas con el ámbito laboral, el agotamiento y el desgaste. El siguiente análisis del libro Self-Care for Teachers (Allen, 2013 revisa la investigación internacional sobre el tema y propone un enfoque alternativo. La investigación no solo confirma este patrón persistente de exceso de estrés, trabajo y enfermedad, sino que también corrobora la típica falta de atención de los educadores a sus propias necesidades. Los enfoques convencionales para solucionar el problema del exceso de estrés, de trabajo y las enfermedades concomitantes se centran en factores externos: estrategias de gestión tales como programas de orientación y asesoramiento, incentivos salariales o, más recientemente, líneas de ayuda y programas de bienestar para los maestros. El autor aboga por un enfoque más equilibrado, buscando soluciones para este desconcertante problema tanto interna como externamente. Aunque el equilibrio a menudo se concibe como un ideal estático de simetría y proporción, puede ser mejor entendido –especialmente en un contexto educativo– como el proceso dinámico y práctico de “moverse ingeniosamente entre los extremos”, una definición que podría aplicarse igualmente al manejo del aula, al diseño curricular, a las estrategias de evaluación, al desarrollo profesional, a las actitudes prevalentes y al ritmop ersonal y laboral. Palabras clave: Estrés excesivo, balance, autocuidado.

  8. El análisis económico del derecho de autor y del copyright, un estudio del equilibrio entre los intereses público y privado

    Directory of Open Access Journals (Sweden)

    Ana María Pérez Gómez Tétrel

    2007-01-01

    Full Text Available La propiedad intelectual ha sido concebida para responder, tanto a la necesidad de protección del autor de una obra del intelecto, como al beneficio que la sociedad pueda sacar del acceso a dichas creaciones intelectuales, generando así un equilibrio entre los diferentes actores. Los sistemas digitales de comunicación han puesto en jaque dicho equilibrio. Conviene preguntarse ¿es capaz la protección otorgada por el derecho a la creación intelectual, de establecer un equilibrio en las relaciones entre creador (autor y la sociedad (consumidor? ¿En qué medida el análisis económico comparado del derecho de autor y del copyright puede contribuir al modelo económico de este equilibrio? ¿Hasta qué punto, el rol desempeñado por las industrias de la comunicación está rompiendo este equilibrio? El objetivo de este artículo es analizar diversos aspectos del derecho de autor y del copyright, a la luz del análisis económico del derecho.

  9. El análisis económico del derecho de autor y del copyright, un estudio del equilibrio entre los intereses público y privado

    Directory of Open Access Journals (Sweden)

    Ana María Pérez Gómez Tétrel

    2007-11-01

    Full Text Available La propiedad intelectual ha sido concebida para responder, tanto a la necesidad de protección del autor de una obra del intelecto, como al beneficio que la sociedad pueda sacar del acceso a dichas creaciones intelectuales, generando así un equilibrio entre los diferentes actores. Los sistemas digitales de comunicación han puesto en jaque dicho equilibrio. Conviene preguntarse ¿es capaz la protección otorgada por el derecho a la creación intelectual, de establecer un equilibrio en las relaciones entre creador (autor y la sociedad (consumidor? ¿En qué medida el análisis económico comparado del derecho de autor y del copyright puede contribuir al modelo económico de este equilibrio? ¿Hasta qué punto, el rol desempeñado por las industrias de la comunicación está rompiendo este equilibrio? El objetivo de este artículo es analizar diversos aspectos del derecho de autor y del copyright, a la luz del análisis económico del derecho.

  10. Intervención mediante feedback auditivo para la mejora del equilibrio en mujeres que realizan actividad física

    Directory of Open Access Journals (Sweden)

    Eugenio A. P\\u00E9rez C\\u00F3rdoba

    2014-01-01

    Full Text Available El equilibrio es un aspecto fundamental para las actividades de la vida diaria y para el deporte. El deterioro en esta capacidad puede ocasionar trastornos o lesiones por caídas. El objetivo de esta intervención es determinar la influencia de un programa de ejercicios propioceptivos con feedback externo auditivo sobre la mejora del equilibrio. Participaron ocho mujeres (M = 38 años, DE = 11.45 que realizaban ejercicio constante, dividas en dos grupos. Grupo 1 programa y feedback auditivo, grupo 2 solo programa. Se creó un equipo de feedback auditivo que fue utilizado para el grupo 1. En los resultados el Grupo 1 tuvo la mejoría significativa en equilibrio medido con los siguientes test: Functional Reach (p = .036, Get Up and Go (p = .021 y Test Dinámico en Barra (p = .044. De acuerdo a los resultados obtenidos, los dos grupos presentan una mejoría en el equilibrio por el programa propioceptivo, pero es el grupo 1 con feedback auditivo, el que tuvo la mayor mejoría. El programa propioceptivo unido a feedback auditivo puede mejorar significativamente el equilibrio.

  11. Sistema experimental para la medición del ángulo de equilibrio entre imanes y superconductores

    OpenAIRE

    Valiente Blanco, Ignacio

    2010-01-01

    La expulsión del campo magnético del interior de un superconductor debido al efecto Meissner genera un conjunto de fuerzas que son capaces de hacer levitar un imán. Las fuerzas generadas por este efecto han sido estudiadas indirectamente en este proyecto midiendo el ángulo girado por un imán sometido a efecto Meissner- Oschenfeld en su posición de equilibrio. Las interacciones de las distintas superficies de la pastilla superconductora con el imán para diferentes posiciones relativas entre es...

  12. EQUILIBRIO TRABAJO-FAMILIA, SATISFACCIÓN LABORAL Y APOYO FAMILIAR EN DOCENTES DE ESCUELAS BÁSICAS

    OpenAIRE

    Abarca Valenzuela, Sofía; Letelier Ferrada, Antonia; Aravena Vega, Verónica; Jiménez Figueroa, Andrés E.

    2016-01-01

    Resumen El objetivo general del estudio consistió en identificar la relación entre las variables Equilibrio trabajo-familia, Satisfacción laboral y Apoyo familiar en una muestra de noventa y nueve docentes, pertenecientes a establecimientos municipales de educación básica, a quienes se les administró el cuestionario de Interacción Trabajo-Familia SWING, el Inventário de Percepção de Suporte Familiar (IPSF) y el Cuestionario de Satisfacción Laboral S20/23. Se concluye que para mejorar la relac...

  13. El dinero en modelos de equilibrio general sobre la no-neutralidad del dinero, una nota introductoria

    Directory of Open Access Journals (Sweden)

    Garay S. Jose Luis

    1990-12-01

    Full Text Available Sólo en la medida en que el dinero sea concebido dentro de un esquema de equilibrio general; es posible llegar a comprender en su integridad, tanto las funciones como la naturaleza misma de la moneda. De otra manera, si se incorpora «desde afuera" el dinero en modelos en los que se supone la existencia de un equilibrio, independientemente de la mediación del dinero es decir, un equilibrio de trueque, que posteriormente es especificado en unidades monetarias, mediante la introducción artificial del dinero se dificulta entender el papel del dinero en la economta. Esto es asi; porque se le niega de partida toda función real al dinero en la economia capitalista. La revisión de las distintas teorías sobre el rol de la moneda: la de la dicotomia neoclásica, las expectativas adaptativas y, las expectativas racionales muestra que la teoria supone que el dinero existe pero no explica el por qué de su existencia; la pretendida neutralidad del dinero y de la política monetaria no está probada ni siquiera en los modelos más simples; y cuando se conoce el dinero como activo propiamente tal; la teoría neoclásica pierde su marco de referencia. La alternativa al modelo de Equilibrio General; Arrow-Debreu es una teorta que explique la intertemporalidad de las decisiones económicas, la
    demanda de dinero como activo, el hecho de que el dinero es una institución social y que evoluciona junto con la sociedad. La tarea no es fácil y la teoria convencional no puede simplemente ser ignorada: es un análisis de un caso particular, en el marco de la heurlstica propia del programa
    de investigación cienttfica de las teortas clásica y neoclásica. Pero es esa heurfstica la principal restricción para avanzar en modelos más aproximados a la realidad. La teoría «verdadera" de la moneda está por construir.

  14. Equilibrios de precipitación. Influencia del pH sobre la solubilidad del acetato de plata. Problema interactivo.

    OpenAIRE

    Milla González, Miguel

    2015-01-01

    Se estudia como influye la variación del pH en la solubilidad de una sal cuya parte aniónica es una base débil. Es el caso del acetato de plata. Mediante una animación se muestra el desplazamiento del equilibrio hacia una mayor solubilización. El paso siguiente es encontrar una expresión sencilla que relaciona la solubilidad con el pH y se representa gráficamente dicha función mediante una hoja de cálculo.

  15. Nash, el último fundador de la teoría de juegos, y la evolución del concepto de equilibrio desde Cournot

    OpenAIRE

    Streb, Jorge M.

    2015-01-01

    Nash recibió el premio Nobel de economía por dos aportes fundamentales: la distinción entre juegos cooperativos y no cooperativos, y el concepto de solución básico para juegos no cooperativos. Myerson indica que este equilibrio es el concepto de solución básico de teoría de juegos dado que, como señala Nash, los juegos cooperativos se pueden reducir a un juego no cooperativo más amplio agregando la negociación previa. El equilibrio de Nash puede verse también como equilibrio de Cournot-Nash p...

  16. La aplicación del principio del equilibrio económico a contratos estatales sometidos al régimen normativo del derecho privado

    Directory of Open Access Journals (Sweden)

    Manuela Canal-Silva

    2016-06-01

    Full Text Available En vista de la importancia del equilibrio económico del contrato dentro del marco de la contratación pública, el presente artículo pretende demostrar la procedencia de su aplicación a los contratos estatales sometidos al régimen del derecho privado. Mediante la reflexión y el estudio de la jurisprudencia sobre el tema se presentarán los principales motivos expuestos por las providencias que apoyan la tesis planteada. Se exponen así los temas del interés colectivo y los preceptos constitucionales como bases de este principio del equilibrio económico. Para luego examinar la conmutatividad del contrato y el debate frente a la consideración del equilibrio económico como un principio transversal al derecho público y privado.

  17. Competitividad privada, costos de producción y análisis del punto de equilibrio de unidades representativas de producción porcina

    OpenAIRE

    Isidro Martínez Medina; Daniel Val Arreola; Rafael Tzintzun Rascón; José de Jesús Conejo Nava; Manuel Jaime Tena Martínez

    2015-01-01

    Se utilizó la Matriz de Análisis de Políticas (MAP) y el Análisis del Punto de Equilibrio (PE) para determinar la competitividad privada, la estructura de costos y el punto de equilibrio de once unidades de producción porcina (UPP). Considerando precios corrientes de mercado de 2010, las UPP L340, L234, H726, P55, P250, H52 y H120 fueron rentables y competitivas. Cada $0.4 y $0.9 invertidos en factores internos generaron un valor agregado de $1, cubriendo los costos de los factores internos d...

  18. La percepción de beneficios y de mejora del equilibrio motriz en programas de actividad física en la tercera edad

    OpenAIRE

    Castañer, Marta; Saüch, Glòria; Prat, Queralt; Camerino, Oleguer; Anguera Argilaga, María Teresa

    2016-01-01

    Nuestro objetivo es estudiar la percepción de los beneficios y de la mejora del equilibrio motriz que tienen los participantes de la tercera edad en un programa de actividad física. Realizamos un enfoque mixed methods de tipo embedded design de los datos obtenidos de la observación sistematizada de los patrones motrices que generan programas dirigidos a este colectivo; la administración de un test estandarizado de equilibrio en geriatría y un cuestionario validado. Se analiz...

  19. Troca de gases prejudicada em pacientes com angina instável Deterioro del intercambio gaseoso en pacientes con angina inestable Impaired gas exchange in patients with unstable angina

    Directory of Open Access Journals (Sweden)

    Dayane Horta Rocha

    2009-09-01

    Full Text Available A identificação do diagnóstico de enfermagem "troca de gases prejudicada na assistência aos pacientes com angina" é visualizada rotineiramente, porém faz-se necessário um aprofundamento desta temática. Com o objetivo de analisar a ocorrência deste diagnóstico, realizamos um estudo transversal, de caráter descritivo-exploratório, com pacientes internados em um hospital especializado. Os dados foram obtidos por meio de entrevista, exame físico e consulta ao prontuário. O diagnóstico "troca de gases prejudicada" foi ausente em nossa amostra; entretanto, as variáveis profundidade da respiração, pressão arterial sistólica, sonolência e sódio sérico estiveram comprometidas, o que indica risco de agravamento. Visualizamos alguma relação entre os resultados obtidos e características do estilo de vida dos pacientes avaliados, o que reforça a importância de medidas preventivas para a obtenção de um melhor prognóstico na assistência aos pacientes com angina.La identificación del diagnóstico realizado por parte de la enfermería del Deterioro del intercambio gaseoso en el cuidado de pacientes con angina es comúnmente percibida, sin embargo es necesario profundizar esta temática. Con el objetivo de analizar la ocurrencia del diagnóstico del Deterioro del intercambio gaseoso en portadores de Angina Inestable desarrollamos un estudio transversal, de carácter descriptivo-exploratorio, con pacientes ingresados en un hospital especializado. Los datos fueron recolectados por medio de entrevistas, examenes físicos y consultas a los registros médicos. Este diagnóstico no fue identificado en nuestra muestra, sin embargo, las variables profundidad de la respiración, presión arterial sistólica, somnolencia y sodio sérico presentaron alteraciones , lo que indica riesgo de agravación del cuadro clínico. Se identificó una relación entre los resultados obtenidos y las características del estilo de vida de los pacientes

  20. Equilibrio Trabajo-Vida: Proceso de transformación hacia una organización familiarmente responsable

    Directory of Open Access Journals (Sweden)

    María Candela Rodríguez

    2016-12-01

    Full Text Available El equilibrio entre el trabajo y la vida personal de los empleados se ha convertido en un tema ampliamente estudiado en la literatura académica, particularmente en el campo del Management. Las organizaciones han comenzado a implementar estrategias tendientes a revertir los efectos negativos que genera el desequilibrio entre estos dominios en el desempeño de los empleados. Específicamente, se ha incrementado considerablemente el uso de políticas de conciliación trabajo-vida, como horarios flexibles y trabajo desde el hogar. Sin embargo, existe poco conocimiento sobre el proceso que deben atravesar las organizaciones para implementar estas políticas y convertirse en una organización familiarmente responsable, que promueve el equilibrio trabajo-vida de sus empleados. De esta manera, el objetivo de este trabajo es analizar ese proceso de transformación, identificando los factores claves que intervienen durante la implementación de las políticas de conciliación. Para ello, se ilustrará el proceso con el caso de una empresa que se encuentra atravesando este cambio.

  1. Equilibrio trabajo-familia, satisfacción laboral y apoyo familiar en docentes de escuelas básicas

    Directory of Open Access Journals (Sweden)

    Sofía Abarca Valenzuela

    2016-01-01

    Full Text Available El objetivo general del estudio consistió en identificar la relación entre las variables Equilibrio trabajo-familia, Satisfacción laboral y Apoyo familiar en una muestra de noventa y nueve docentes, pertenecientes a establecimientos municipales de educación básica, a quienes se les administró el cuestionario de Interacción Trabajo-Familia SWING, el Inventário de Percepção de Suporte Familiar (IPSF y el Cuestionario de Satisfacción Laboral S20/23. Se concluye que para mejorar la relación y el equilibrio en la interfaz trabajo-familia es indispensable contar con políticas organizacionales amigables hacia la familia, sobre todo en las prestaciones que la organización despliega para apoyar a sus trabajadores. No obstante contar con el apoyo familiar, como un lugar de recuperación y de comprensión, es fundamental para dar respuesta a las demandas de estos dos ámbitos.

  2. MEDICIÓN DEL EQUILIBRIO LIQUIDO-VAPOR DEL SISTEMA METANOL-ACETATO DE METILO A 580 mmHg

    Directory of Open Access Journals (Sweden)

    Carlos Ariel Cardona

    2008-03-01

    Full Text Available En este trabajo se midió experimentalmente el equilibrio líquido-vapor para el sistema binario metanol–acetato de Metilo a 580 mmHg. Las mediciones experimentales fueron realizadas utilizando un equipo con recirculación tipo Cottrell. Los datos obtenidos fueron comparados con los resultados adquiridos de la simulación del equilibrio líquido-vapor del sistema bajo estudio. En la simulación se empleó el modelo de actividad NRTL para representar la no idealidad de la fase líquida (con parámetros encontrados en la literatura, y la ecuación de estado de Hayden O´Connel para la no idealidad de la fase vapor. De igual manera, se correlacionaron los datos para encontrar nuevos parámetros del modelo de actividad en NRTL. Además, a partir de datos experimentales medidos a 760 mmHg encontrados en la literatura para el sistema estudiado, se verificó la Ley de Vresky, la cual permite, sin necesidad de cálculos rigurosos, predecir la dirección de desplazamiento de un azeótropo binario cunado se varía la presión del sistema.

  3. La tradizione nella scienza il progresso scientifico come equilibrio dialettico tra idee innovatrici e tradizione in una raccolta di saggi inediti

    CERN Document Server

    Heisenberg, Werner

    1982-01-01

    In questa raccolta di saggi (inediti per l'Italia), da lui stesso selezionati poco prima della morte, Heisenberg analizza da varie angolazioni i rapporti tra progresso scientifico e tradizione : la storia della scienza è soprattutto una storia di idee, e da un giusto equilibrio dialettico tra i nuovi concetti e la tradizione, che costituisce la base ideale per discuterli, scaturisce il progress scientifico.

  4. Humedad de equilibrio y calor latente de vaporización del ajonjolí. Sésamun indicum L.

    Directory of Open Access Journals (Sweden)

    Julio E. Ospina M.

    1995-01-01

    Full Text Available El ajonjolí (Sésamun indicum L., es una oleaginosa originaria de África y cultivada en las regiones tropicales y subtropicales de Asia y América. A los 110 días de sembrada se cosecha la semilla la cual se utiliza como materia prima especialmente en la industria de grasas y aceites comestibles. Actualmente se pierden en Colombia, un alto porcentaje de semillas durante el proceso de secado natura en el campo. Debido a la falta de información técnica, científica en secado y almacenamiento del grana de ajonjolí se procedió a estudiar la metodología para determinar, el contenido de humedad por el método de la estufa, las curvas y modelo para cuantificar la humedad de equilibrio y el calor latente de vaporización.

  5. Influencia de un programa de ejercicio físico sobre la marcha y el equilibrio en personas con demencia

    OpenAIRE

    López García, Ana

    2012-01-01

    Objetivos: Analizar cómo varían los efectos del ejercicio físico sobre la marcha y el equilibrio de enfermos con demencia que asisten a un centro de día según sexo, edad, tipo de demencia, grado de deterioro, nivel de dependencia y tiempo desde diagnóstico. Material y método: Se han valorado 25 (6 varones; edad media 76,44 DE 8,81) sujetos con demencia (76% Alzheimer) cada seis meses en un año durante el cuál realizaron cinco sesiones semanales de ejercicio físico dirigido de 45 minutos. ...

  6. Diagramas de equilibrio para la extracción con solvente de aceite e insecticida de semilla molida de nim

    Directory of Open Access Journals (Sweden)

    R. Espinosa

    2006-01-01

    Full Text Available En este trabajo se construyeron diagramas de equilibrio para la extracción con hexano de aceite de la semilla molida de nim (GNSK y de la extracción posterior con etanol de insecticida de la GNSK sin aceite. Los datos experimentales fueron obtenidos a diferentes temperaturas, poniendo en contacto sólido y solvente en diferentes proporciones en frascos Erlenmeyer. Se suministró agitación y se mantuvo la temperatura controlada hasta alcanzar el equilibrio. La composición del extracto y del refinado se determinó separando los solventes por evaporación. Se propone ecuaciones para la curva de refinado y la curva de distribución. En ambas extracciones, la fracción de solución retenida dentro de la estructura celular del sólido molido aumenta con la temperatura. La concentración del extracto tiene más influencia en la cantidad de solución retenida para la extracción de insecticida que para la extracción de aceite. Para extractos diluidos, la concentración de soluto tiende a ser mayor en el extracto que en la solución retenida. Esta tendencia es más pronunciada cuando la temperatura aumenta. A temperaturas cercanas al punto de ebullición, hay mayor tendencia a la retención de solvente por el sólido, a cualquier concentración.

  7. Determinación de la humedad de equilibrio en panela Equilibrium humidity determination in molases (panela

    Directory of Open Access Journals (Sweden)

    Macias Esparza Belisario

    1990-12-01

    Full Text Available El objetivo del presente estudio fue determinar los mejores estados atmosféricos para el almacenamiento de la panela analizando el contenido de humedad de equilibrio del edulcorante, a unas condiciones estables de temperatura y humedad relativa. Utilizando regresión lineal para el análisis
    de los datos, se obtuvo una ecuación multivariable de tipo exponencial, aplicable para regiones que poseen ternepratu ras entre 13°C y 34°C y humedades relativas entre 60% y 90%. la panela tal como se produce actualmente, con contenidos de humedad entre 80% y 10% base húmeda, solo podrá almacenarse durante períodos muy cortos de tiempo. Para perradas más largos, la panela debe almacenarse en condiciones ambientales que garanticen humedades de equilibrio inferiores al 7%.The aim of the present research was to establish the best environmental conditions related to the storage, over a long
    period of time, for panela (unrefined brown sugar blocksL
    In order to define those conditions, it was necessary to determine equilibrium moisture curves related to a range of temperature between 13°C and 34°C, and a relative humidity range between 60Ofo and 90%, which covers the environmental conditions of many panela's production regions. A linear regression analysis was applied to obtain a multi-variable equation which allows the definition of equilibrium moisture curves, mentioned above. Actual panela's moisture content (8% to 10% on wet basis, allows its storage only, for a short time under temperature and
    relative humidity ranges normally founded in production regions in order to prolong it, storage room environmental conditions must be adjusted to obtain an equilibrium moisture
    content of 7% meximum.

  8. Plasma Equilibrium in a Torus with High-Frequency Fields and Plasma Heating Resulting from the Development of a Powerful Beam of ''Escaping Electrons''; Plasma Torique: Stabilisation au Moyen de Champs de Haute Frequence et Chauffage par Formation d'un Flux Intense d'Electrons 'Emballes'; Ehksperimental'noe issledovanie ravnovesiya plazmy v tore pri nalichii vysokochastotnykh polej i nagreva plazmy za schet razvitiya moshchnogo puchka ''ubegayushchikh ehlektronov''; Equilibrio del Plasma en un Toro, en Presencia de Campos de Alta Frecuencia, y Calentamiento del Plasma por el Desarrollo de un Haz Potente de 'Electrones Desbocados '

    Energy Technology Data Exchange (ETDEWEB)

    Demirkhanov, R. A.; Kirov, A. G.; Stotland, M. A.; Malykh, N. I.; Horasanov, G. L.; Vishnevskij, N. K.; Gutkin, T. I.; Jampol' skij, I. R. [Fiziko-Tehnicheskij Institut Gosudarstvennogo Komiteta po Ispol' zovaniju Atomnoj Ehnergii SSSR, Sukhumi, SSSR (Russian Federation)

    1966-04-15

    The paper describes experiments conducted on the ''RT-0'' apparatus. It consists of a torus with large diameter 100 cm and with small diameter 10 cm. A toroidal magnetic field about 6 kOe is established along the chamber. The plasma is ignited at {>=}5 x 10{sup -4} Torr by means of a longitudinal rotating electric field of f = 8.3 Mc/s. Rotating around the small diameter is a high-frequency (540 kc/s) quadrupole field with H{phi} = 200 Oe at the chamber walls. When the low-induction capacitor bank is discharged on the loops located along the torus, a damped vortical electric field with maximum strength E{sub z} = 200 V cm{sup -1} and with half-period about 1 {mu}s may be generated within the chamber. The purposes of the experiments were: 1) To explain the equilibrium and stabilization of plasma in a quasi-constant toroidal magnetic field by using routing multipole high-frequency fields, on the assumption that the toroidal drift force, equal to Tilde-Operator (r/R)nkt, must be compensated by the electromagnetic wave pressure H{sup 2}/8{pi}; 2) To study the heating of plasma resulting from dissipation of the ''beam'' instability produced by a powerful beam of ''escaping electrons'' when the electric fields in the plasma are characterized by Ez >> Ec. The apparatus was used to carry out: a) Microwave measurements of plasma density, by using an interferometer of wave length {lambda} =2 mm, and observation of the plasma boundary by the reflected signal on the wave {lambda} = 17 mm; b) Recording of the behaviour of the H{sub {beta}} line in time and scanning of plasma luminescence in time, by using a photoelectric converter; c) measurement of the total intensity of the X-radiation in time, by using a scintillation counter; d) measurement of the current in the plasma and of the voltage in the bypass. The results show that a high-frequency igniting field of 8.3 Mc/s creates a plasma touching the walls with an average electron density 0.5 to 1 x 10{sup 13} cm{sup -3} and an

  9. Studies of the balance 210Pb - 210Po in glasses; Estudios del equilibrio 210Pb - 210Po en vidrios

    Energy Technology Data Exchange (ETDEWEB)

    Torre Pérez, J. de la; Martín Sánchez, A.; Ruano Sánchez, A.B.

    2014-07-01

    Retrospective dosimetry requires measurement methods allowing the determination of Radon concentration in the past. One of the such methods is based on the direct measurement of 210Po implanted on the surface of objects, whose activity concentration (Bq/m2), is directly related to the cumulative exposure due to the concentration of 222Rn (Bq/m3) for long time. These determinations are possible taking into consideration the equilibrium between 210Po (T1/2 = 138.378 days) and its parent 210Pb (T1/2 = 22.3 years), being both radionuclides from the 222Rn progeny. In previous works about the determination of the conversion factor (ratio between the concentration of 210Po in objects and the retrospective 222Rn concentration in air), Corresponding equilibria between descendants were assumed. In this work, an experimental study about the equilibrium 210Pb - 210Po in glasses, which were previously exposed to some radon concentrations, has been performed. Two scenarios were studied: a place with, and another place without, continuous cumulative 222Rn concentration. Results were compared with those reached by theoretical calculations from the (Bateman) activity evolution equations. [Spanish] La dosimetría retrospectiva requiere métodos de medida que permitan la determinación de la concentración de radón en el pasado. Uno de estos métodos está basado en la medida directa del 210Po implantado sobre la superficie de objetos, cuya concentración de actividad (Bq/m2), está directamente relacionada con la exposición acumulativa debida a la concentración de 222Rn (Bq/m3) durante largos períodos de tiempo. Estas determinaciones son posibles gracias al equilibrio entre el 210Po (T1/2 = 138,378 días) y su progenitor, el 210Pb (T1/2 = 22,3 años), siendo ambos radionúclidos descendientes del 222Rn. En trabajos anteriores sobre la determinación del factor de conversión (relación entre la concentración de 210Po en los objetos y la concentración de 222Rn retrospectivo en

  10. Competitividad privada, costos de producción y análisis del punto de equilibrio de unidades representativas de producción porcina

    Directory of Open Access Journals (Sweden)

    Isidro Martínez Medina

    2015-01-01

    Full Text Available Se utilizó la Matriz de Análisis de Políticas (MAP y el Análisis del Punto de Equilibrio (PE para determinar la competitividad privada, la estructura de costos y el punto de equilibrio de once unidades de producción porcina (UPP. Considerando precios corrientes de mercado de 2010, las UPP L340, L234, H726, P55, P250, H52 y H120 fueron rentables y competitivas. Cada $0.4 y $0.9 invertidos en factores internos generaron un valor agregado de $1, cubriendo los costos de los factores internos de producción, generando ganancia que fluctuó entre 1 y 10 %. El costo de producción promedio de 1 kg de cerdo en pie en las UPP estudiadas durante 2010 fue de $22.3, constituido por los insumos comerciables, los factores internos y los insumos indirectamente comerciables: 86.5, 6.8 y 6.7 % respectivamente, los rubros más representativos fueron: el alimento (75.9%, las medicinas (8.1%, la mano de obra (5.2 % y los combustibles (1.6 %. El costo de producción más alto se encontró en las UPP ubicadas en Huandacareo; ($22.8 seguidas por las UPP de La Piedad ($22.3 y Purépero ($21.9. Las UPP utilizaron entre el 44.1 y 115.4 % de sus ingresos para equiparar sus costos y alcanzar su punto de equilibrio. El tamaño no fue una condicionante de la mayor rentabilidad, la mayor competitividad privada, los menores costos de producción y el punto de equilibrio más bajo en las UPP estudiadas.

  11. Equilibrio económico y su efecto sobre la litigiosidad en la contratación pública en Colombia

    Directory of Open Access Journals (Sweden)

    Yuri Gorbaneff

    2009-10-01

    Full Text Available La contratación pública en Colombia es conflictiva, poco eficaz y eficiente, y con frecuencia causa daño patrimonial al Estado. El sistema legal colombiano no fue capaz de hacer eficiente y transparente la contratación pública.  Esto ocurre porque la contratación pública transcurre en un ambiente institucional que se caracteriza por los altos costos de transacción. La ley colombiana complica las cosas aún más con el principio del equilibrio económico de los contratos, que aumenta la incompletitud contractual y hace difícil utilizar los incentivos económicos para controlar el oportunismo de los agentes económicos. Los autores formulan la hipótesis de que el principio del equilibrio económico contribuye a aumentar la litigiosidad en la contratación pública. Se hace la prueba empírica de la hipótesis. En la primera sección se realiza el resumen de la literatura económica sobre los costos de transacción y el contrato incompleto, así como la literatura jurídica sobre el origen histórico del principio del equilibrio económico de los contratos. La segunda sección describe la metodología del estudio empírico. La tercera, presenta la evidencia empírica de los efectos que ejerce el principio del equilibrio sobre la contratación pública. Finalmente, se presentan las conclusiones.

  12. Estudio de la síntesis de acetato de butilo - 2. Análisis de las condiciones de equilibrio químico

    Directory of Open Access Journals (Sweden)

    Álvaro Orjuela Londoño

    2005-09-01

    Full Text Available En este trabajo se adelantó un estudio de la reacción de esterificación de ácido acético y n-butanol en fase líquida (P atm = 560 mmHg, utilizando una resina de intercambio iónico (Lewatit K-2431 como catalizador. Se efectuaron ensayos para determinar la influencia de la carga del catalizador, la temperatura y la relación molar de alimentación (ácido/alcohol, sobre la constante de equilibrio quImico. Se pudo reconocer el fenómeno de adsorción selectiva de los componentes sobre la matriz de la resina, y se comprobó su efecto sobre las condiciones de equilibrio quImico, para diferentes relaciones iniciales de ácido y alcohol. Se utilizó un modelo no ideal (UNIQUAC para evaluar las actividades de los componentes, y se realizó el cálculo de la energIa libre y la entalpIa estándares de la esterificación ( AG°= -1.874 Kcal/mol, AH°= -5.335 Kcal/mol, las cuales corresponden con lo reportado en trabalos previos. Finalmente, se obtuvo una expresión que permite evaluar la constante de equilibrio quImico, de carácter aparente, donde se toman en cuenta los efectos térmicos y los asociados al equilibrio de fases lIquido-polImero. Dicha expresión concuerda con los datos experimentales y con los reportados en otros estudios.

  13. Evolución del equilibrio estático y dinámico desde los 4 hasta los 74 años

    Directory of Open Access Journals (Sweden)

    Josep Cabedo i Sanromà

    2008-06-01

    Full Text Available La investigación que presentamos proporciona una descripción del equilibrio durante el ciclo vital –desde los 4 hasta los 74 años–, y tiene como objetivo principal el análisis, la valoración y la reflexión, sobre su evolución en dos pruebas: una de equilibrio estático y otra de dinámico. En el apartado de metodología quedan detallados los protocolos de administración y condiciones de observación necesarios para utilizar estos dos tests, por parte de los diferentes profesionales de la actividad física y de otros profesionales que los puedan necesitar. Al mismo tiempo, y con una vocación de ofrecer un servicio social, adjuntamos los baremos por edades de las pruebas de equilibrio estático y dinámico. Los datos expuestos denotan un aumento exponencial del rendimiento en las primeras edades, hasta llegar a los 18 años; los mejores resultados se alcanzan de los 19 a los 23 años y se mantienen hasta los 30. A partir de los 33 años, la curva describe una involución hasta el final del ciclo, con un punto de inflexión más acentuado a los 53 años.

  14. Análisis de las discusiones de los estudiantes en una clase de laboratorio sobre el equilibrio químico

    Directory of Open Access Journals (Sweden)

    Adriana Bertelle

    2014-01-01

    Full Text Available En este trabajo se estudia las discusiones de los estudiantes de primer ano de dos carreras universitarias, durante la realización de un trabajo practico de laboratorio sobre el tema de equilibrio químico. Se analizan los argumentos que construyen los estudiantes cuando relacionan los datos experimentales y las observaciones con el conocimiento químico que poseen. Se registra en audio y video el trabajo grupal de los mismos mientras desarrollan la clase de laboratorio y como instrumento de análisis se utiliza, el patrón argumentativo de Toulmin. Uno de los aspectos relevantes de las clases analizadas, es que son escasas las discusiones de los estudiantes durante el desarrollo del trabajo de laboratorio y que los mismos no hacen explicita la nocion de sistema en equilibrio que están elaborando. Se puede concluir, en general que el desarrollo del trabajo practico de laboratorio, no aporto a lo que debería contribuir, que es que los estudiantes desarrollen una conceptualizacion mas acabada, de lo que es un sistema en equilibrio químico.

  15. Estrategias de enseñanza basadas en el estudiante para el aprendizaje del equilibrio químico

    Directory of Open Access Journals (Sweden)

    Juana Domitila Asuaje Cordero

    2015-10-01

    Full Text Available El estudio compara el efecto en el rendimiento estudiantil por la estrategia de Aprendizaje Basado en Problemas (ABP y la enseñanza por descubrimiento guiado, para el aprendizaje del equilibrio químico en estudiantes cursantes del primer semestre de la asignatura Química I de la carrera de Agronomía de la Universidad Centroccidental Lisandro Alvarado de Venezuela, durante el año académico 2010. Se utilizó una muestra de 40 estudiantes, que se dividió en dos grupos (A y B. Los resultados indican que los estudiantes objeto del ABP registraron un rendimiento significativamente superior en terminos del promedio de las calificaciones, todo ello en contraste con el desempeño de los estudiantes a quienes se les aplicó la estrategia enseñanza por descubrimiento guiado. AbstractThis research study aims to campare the effects of problem-based learning and guided learning on students' academic performance, in a first-semester group of Agronomy students at Universidad Centroccidental Lisandro Alvarado de Venezuela in 2010. The study was carried out in Chemistry I, when they learnt about chemical equilibrium. A sample of 40 students divided into two groups (A and B was used. The results show that the students taught with problem-based learning technique obtained a higher academic performance in relation to the students' mark promedy; in contrast with the students who were applied the guided learning strategy.

  16. Equilibrium reconstruction in the TCA/Br tokamak; Reconstrucao do equilibrio no tokamak TCA/BR

    Energy Technology Data Exchange (ETDEWEB)

    Sa, Wanderley Pires de

    1996-12-31

    The accurate and rapid determination of the Magnetohydrodynamic (MHD) equilibrium configuration in tokamaks is a subject for the magnetic confinement of the plasma. With the knowledge of characteristic plasma MHD equilibrium parameters it is possible to control the plasma position during its formation using feed-back techniques. It is also necessary an on-line analysis between successive discharges to program external parameters for the subsequent discharges. In this work it is investigated the MHD equilibrium configuration reconstruction of the TCA/BR tokamak from external magnetic measurements, using a method that is able to fast determine the main parameters of discharge. The thesis has two parts. Firstly it is presented the development of an equilibrium code that solves de Grad-Shafranov equation for the TCA/BR tokamak geometry. Secondly it is presented the MHD equilibrium reconstruction process from external magnetic field and flux measurements using the Function Parametrization FP method. this method. This method is based on the statistical analysis of a database of simulated equilibrium configurations, with the goal of obtaining a simple relationship between the parameters that characterize the equilibrium and the measurements. The results from FP are compared with conventional methods. (author) 68 refs., 31 figs., 16 tabs.

  17. Teorí­as de primer y segundo orden sobre el potencial de ciertas figuras de equilibrio de cuerpos celestes

    Science.gov (United States)

    Gumbau, Manuel Forner

    2010-11-01

    Uno de los problemas que aborda la Mecánica Celeste es la determinación de las figuras de equilibrio de los cuerpos celestes. Para investigar su solución mediante métodos directos, se precisa evaluar el potencial generado por su autogravitación, el generado por su fuerza centrí­fuga y el generado por la fuerza de atracción entre los cuerpos. Los métodos clásicos de Finlay y Kopal que afrontan estos problemas, para determinar el potencial autogravitatorio en las configuraciones de equilibrio, emplean desarrollos en serie de los potenciales interior y exterior del potencial autogravitatorio. Estos métodos incurren en el error de suponer la convergencia en capas donde resulta cuestionable dicha convergencia para estos desarrollos en serie. En este trabajo se han elaborado unos algoritmos que contemplan toda la casuí&stica y que permiten una manipulación efic iente del producto de polinomios de Legendre, del producto de funciones asociada s de Legendre y del producto de armónicos esféricos como combinacióon lineal de ellos mismos, respectivamente. Se han obtenido, para primer y segundo orden en las amplitudes, los desarrollos correctos para los potencial es interior y exterior del potencial autogravitatorio para configuraciones de equilibrio aisladas, y , en primer orden de amplitudes, los mismos potenciales para los sistemas binarios próximos. Se ha elaborado un método analítico, en primer orden respecto de las amplitudes, para la determinación del potencial de marea en sistemas binarios próximos en el cual se manifiesta la forma de la componente secundaria del sistema

  18. Para leer a Shoven y Whalley: otra introducción práctica al modelamiento aplicado de equilibrio general económico

    Directory of Open Access Journals (Sweden)

    Juan Carlos Segura Ortiz

    2009-07-01

    Full Text Available El objetivo del artículo “Applied General-Equilibrium Models of Taxation and International Trade: An Introduction and Survey” (Shoven & Whalley,1984 es mostrar cómo el esquema walrasiano de equilibrio general puede convertirse en un poderoso instrumento para el análisis de política mediante la parametrización y especificación de un modelo teórico de equilibrio económico, y su posterior solución bajo escenarios contrafactuales. A pesar de que los autores proporcionan un ejemplo numérico detallado y ofrecen una guía para el desarrollo de un proyecto de equilibrio general computable, que hoy constituye la referencia estándar, el acceso a las técnicas descritas sigue siendo dificultoso, aun en un medio como el actual, en el que se dispone de recursos cuya utilización en el tiempo de publicación del artículo de referencia, estaba mediada por altísimos costos. La barrera de entrada está constituida por la dificultad del aprendiz para hacer compatibles sus conocimientos teóricos con la práctica empírica de la formulación y solución numérica. Este artículo contribuye a sobrellevar estos inconvenientes asociados, replicando el modelo numérico en Shoven y Whalley como la búsqueda de la solución numérica del sistema de ecuaciones de exceso de demanda. Se ofrece un modelo computable escrito en GAMS, que puede ser modificado y adaptado para la posterior extensión del esquema básico.

  19. Solución Matricial de Modelos para Cálculo de Equilibrio Líquido-Vapor Matrix Solution of Models to Calculate Liquid-Vapor Equilibrium

    OpenAIRE

    José F Orejel-Pajarito; Raúl González-García

    2008-01-01

    El objetivo de este artículo es demostrar la viabilidad de utilizar modelos termodinámicos de coeficientes de actividad (Wilson, NRTL, UNIQUAC) programados con matrices, en lugar de estar programados con ciclos. Se determina la relación de equilibrio líquido-vapor de las mezclas Metanol-Etanol-Benceno y Acetona-Cloroformo-Metanol representados en mapas de curvas de residuo y en mapas de líneas de destilación. Para obtener resultados más confiables y conclusiones objetivas, el estudio fue apoy...

  20. Análisis de las discusiones de los estudiantes en una clase de laboratorio sobre el equilibrio químico

    OpenAIRE

    Adriana Bertelle; Adriana Rocha; José Manuel Domínguez Castiñeiras

    2014-01-01

    En este trabajo se estudia las discusiones de los estudiantes de primer ano de dos carreras universitarias, durante la realización de un trabajo practico de laboratorio sobre el tema de equilibrio químico. Se analizan los argumentos que construyen los estudiantes cuando relacionan los datos experimentales y las observaciones con el conocimiento químico que poseen. Se registra en audio y video el trabajo grupal de los mismos mientras desarrollan la clase de laboratorio y como instrumento de an...

  1. Efectos de diferentes protocolos de entrenamiento de fuerza sobre la fuerza máxima, la velocidad, la saltabilidad y el equilibrio en estudiantes universitarios

    OpenAIRE

    Naclerio Ayllón, Fernando José; Marín, Pedro J.; Viejo Romero, David; Forte Fernández, Daniel

    2007-01-01

    El objetivo de este estudio es comparar los efectos de tres medios de entrenamiento sobre la fuerza máxima, la saltabilidad, la velocidad y el equilibrio en 24 varones estudiantes universitarios (21.5 ±1.7 años, 1.72± 0.06 m y 75.5±8.7 kg) que entrenaron durante 6 semanas con una frecuencia de 3 veces por semana, realizando 3 ejercicios: sentadilla paralela (SP), split frontal (SF) y extensiones de cadera (EC), siguiendo una periodización creciente-decreciente. Los sujetos fueron divididos en...

  2. Composición y equilibrio corporal de personas con discapacidad intelectual: estudio descriptivo. [Body composition and body balance in people with intellectual disabilities: a descriptive study].

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    Ruth Cabeza-Ruiz

    2016-10-01

    Full Text Available Objetivo: Evaluar la composición corporal y el equilibrio corporal de adultos con discapacidad intelectual. Métodos: Estudio transversal descriptivo y comparación de resultados con valores de referencia presentados en población sin discapacidad. La muestra estuvo compuesta por 86 hombres y 36 mujeres con discapacidad intelectual con edades comprendidas entre los 21 y los 60 años. Se evaluaron el equilibrio estático, dinámico y la composición corporal mediante las pruebas del Alpha-Fit Test Battery for Adults. Resultados: Los resultados obtenidos por los participantes fueron comparados con valores de referencia de personas sin discapacidad y se muestran como media y desviación típica para diferentes grupos de edad. Los análisis descriptivos mostraron que las personas con discapacidad obtuvieron resultados relacionados con un alto riesgo de enfermedad cardiovascular en relación a la composición corporal, presentando la mayoría de ellos sobrepeso y valores elevados de circunferencia de cintura. En relación al equilibrio, tanto en posiciones estáticas como dinámicas, los participantes presentaron resultados vinculados a una baja condición física. Conclusiones: La composición corporal y la capacidad de equilibrio de las personas con discapacidad intelectual evaluadas en el presente estudio son comparables a la de adultos mayores sin discapacidad de referencia. Abstract Purpose: To assess body composition and body balance, both static and dynamic, of adults with intellectual disabilities. Methods: A cross sectional descriptive study was used. 86 men and 36 women with intellectual disabilities participated in the study (21-60 years old. The Alpha-Fit Test Battery for Adults was used to evaluate dynamic and static balance and body composition. Results: Results were compared to published reference values from people without disabilities. Results are showed as mean and standard deviation for each age group. Body composition variables

  3. Introducción a la teoría neoclásica del valor: Teoría del Equilibrio General

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    Eduardo A. Bolaños C

    1994-07-01

    Full Text Available El proyecto científico más importante de la teoría económica pura, de enfoque neoclásico, es el de elaborar un modelo racional del proceso económico de la sociedad capitalista, que sirva de base para la reflexión general sobre este proceso y, principalmente, para la explicación de la magnitudes resultantes de las relaciones económicas que se establecen entre las agentes participantes en él. Esta construcción teórica es el Modelo de Equilibrio General.

  4. The effect of holographic wristbands on body balance. [El efecto de las pulseras holográficas en el equilibrio corporal].

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    Iván Gonzalo

    2014-10-01

    Full Text Available Balance is a complex ability essential for the performance of any motor task and for preventing injuries and falls. The appearance of holographic wristbands, the supposed benefits of which include improved balance, received the attention of the public and the media alike. However, there is no scientific evidence that holograms improve any physical attribute. The aim of this study was to evaluate the effect of Power Balance® holographic wristbands on balance. Following a triple-blind method, 25 healthy and physically active university students (14 women, 11 men underwent the sensory organization test (SOT on two separate days while wearing a wristband with or without holograms (the tests being performed in a random but counterbalanced order. The SOT provides details on total balance and the relative contribution of the three main sensory systems (somatosensory, vestibular and visual involved in balance. The results for the group as a whole revealed the wearing of a holographic wristband to have no significant effect on any of these variables. However, when the women’s results were analyzed separately, the wearing of holographic wristbands was associated with significant differences in the scores of two SOT variables: composite balance (86.5±3.7 with the holographic wristband compared to 85.5±4.5 without it; p≤0.05 and overall mean (93.5±2.0 compared to 92.8±2.4; p≤0.05. Although these statistical differences were discovered, the magnitude of these differences was so small that balance could not have been improved in any practical sense. In conclusion, Power Balance® holographic wristbands exert no meaningful effect on balance in healthy young adults. Resumen El equilibrio es una habilidad compleja esencial para la realización de cualquier tarea motriz y para la prevención de lesiones y caídas. La aparición de las pulseras holográficas, con supuestos beneficios entre los cuales se incluye la mejora del equilibrio, recibió la

  5. Teoría de la Inversión y Mercados Financieros: Valuación de Empresas y Equilibrio Macroeconómico

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    Javier Gerardo Milei

    2007-04-01

    Full Text Available El objetivo del presente trabajo es mostrar, de manera intuitiva, los elementos que brinda la teoría económica para construir proyecciones que sean consistente con el equilibrio de la economía en su conjunto y evitar la toma de decisiones basadas en documentos que pueden constituir verdaderos disparates, los que lamentablemente son muchos más frecuentes que lo que uno desearía. El trabajo se estructura en cuatro bloques. En primer lugar se plantea el contexto bajo el cual se desarrolla la teoría de la inversión, haciendo énfasis especial sobre la teoría “q” desarrollada por James Tobin. A continuación, se construye un marco analítico sobre el cual deberían sustentarse las valuaciones de empresas. Por último, se presentan las conclusiones del trabajo, las cuales sirven de guía no sólo para construir valuaciones consistentes con el equilibrio macroeconómico sino que también son de utilidad para evaluar la calidad de las recomendaciones realizadas por los analistas de inversiones.

  6. Los applets y la mediación pedagógica en la enseñanza del equilibrio químico

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    Vermouth, Nelia

    2011-01-01

    Full Text Available Se implementó una nueva metodología para la enseñanza de las reacciones de equilibrio químico, uno de los temas más importantes en el área química, basado en la hipótesis que el empleo de las nuevas tecnologías en el aula puede motivar a los alumnos a aprender, estimular la autogestión del conocimiento y favorecer el aprendizaje significativo. La modalidad consistió en combinar la enseñanza tradicional con las Tecnologías de la Información y la Comunicación (TICs. Luego de la exposición dialogada del docente, los alumnos trabajaron con applets guiados por un cuestionario orientador. Se trabajó con el concepto de equilibrio y las consecuencias que ocasionan las perturbaciones ejercidas por diversos factores, observando los cambios a través del dinamismo molecular.

  7. Equilíbrio postural de atletas remadores Equilibrio postural de atletas remadores Postural balance in rowing athletes

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    Taian de Mello Martins Vieira

    2006-06-01

    Full Text Available A influência do condicionamento físico no equilíbrio postural por um período prolongado ainda não está esclarecida. O objetivo deste estudo foi comparar parâmetros estabilométricos em testes de longa duração entre atletas remadores e um grupo de indivíduos saudáveis, não-atletas, que permaneceram de pé sobre uma plataforma de força durante 31 minutos. A cada cinco minutos de teste era apresentada uma escala modificada de Borg para pontuar o nível de desconforto. Os parâmetros estudados foram: desvio-padrão, velocidade média e freqüência média dos deslocamentos lateral e ântero-posterior, e a área elíptica do deslocamento do centro de pressão no plano da plataforma. O grupo dos atletas não apresentou diferenças significativas nos parâmetros durante todo o teste. O grupo controle apresentou valores significativamente mais elevados na área elíptica e a velocidade média da metade do teste em diante. Os atletas apresentaram valores significativamente menores para escala de Borg, representando maior resistência ao desconforto gerado pela atividade. Com base nos resultados, sugere-se que as alterações estabilométricas apresentadas pelo grupo de não-atletas sejam decorrentes de processos fisiológicos periféricos e que o condicionamento físico parece ser um fator importante na manutenção do equilíbrio estático por período prolongado.La influencia del condicionamiento físico en el equilibrio postural por un periodo prolongado todavía no está aclarado. El objetivo de este estudio ha sido comparar parámetros estabilométricos en tests de larga duración entre atletas remadores y un grupo de individuos saludables, no atletas, que permanecieron de pie sobre una plataforma de fuerza durante 31 minutos. A cada cinco minutos de prueba era presentada una escala modificada de Borg para puntuar el nivel de incomodidad. Los parámetros estudiados fueron: desvío padrón, velocidad media y frecuencia media de los

  8. Juego de equilibrios

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    Anna Maria Bordas Geli

    2012-07-01

    Full Text Available To undertake large-scale projects requires organising a team that is very large in size. To aide this kind of team organisation ICT, 3D modelling, and File Organisation programmes can be of great use. The danger, however, of using content sharing sites and 3D tools is to believe that everything that can be modelled can be built. This article presents different ways in which the architectural-technological relationship can be understood, and is supported by using the example of the Fondation Louis Vuitton pour la Création project. Locating boundaries, confronting technological challenges, rationalising projects, and building whilst maintaining the magic of the original idea is a task for both the architect and the engineer: key for the success of the project.

  9. Mejora de la coordinación visomotora, percepción visual, atención, equilibrio y estabilidad en personas con discapacidad intelectual a través de la consola Wii

    OpenAIRE

    Sánchez de Arriba, Susana

    2013-01-01

    El objetivo de esta investigación es mejorar habilidades que tengan consecuencias positivas en la vida diaria de las personas con discapacidad intelectual que interactúan con la consola Wii. Para ello a través del juego se potencian las capacidades de coordinación visomotora, percepción visual, atención, equilibrio y estabilidad.

  10. Respuesta a: Comentarios sobre “Puntos de equilibrio asintóticamente estables en nuevos sistemas caóticos”

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    K. Casas-García

    2017-01-01

    Full Text Available Debido a que el Teorema 1 de (Elhadj and Sprott, 2012 es erróneo, algunos de los sistemas encontrados en el artículo (Casas - García et al . 2016 pueden tener orbitas homoclínicas o heteroclínicas pudiendo aparecer caos en el sentido de Shilnikov. Sin embargo, la aportación fundamental de nuestro artículo fue encontrar diez sistemas dinámicos simples, en tres dimensiones, con términos no lineales cuadráticos, que presentan un punto de equilibrio asintóticamente estable y son caóticos, lo cual se logró. Estos se obtuvieron usando el método Monte Car lo aplicado específicamente para la búsqueda de estos sistemas.

  11. El establecimiento y la modificación de tributos como eventos susceptibles de alterar el equilibrio económico del contrato estatal

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    Felipe Rusinque

    2017-12-01

    Full Text Available La jurisprudencia del Consejo de Estado ha admitido, en abstracto, que la creación de un tributo o su modificación durante la ejecución de un contrato estatal son eventos capaces de alterar la ecuación financiera de este. Aquella Corporación ha entendido que el restablecimiento del equilibrio económico quebrado por la imposición o reforma de gravámenes fiscales puede fundarse en la teoría del hecho del príncipe o en la teoría de la imprevisión. Con todo, a pesar de dicho reconocimiento, cuando se analizan las circunstancias propias de cada caso en concreto difícilmente se están cumpliendo los requisitos necesarios para restituir el balance de la ecuación financiera.

  12. GESTIÓN INDIVIDUAL DEL EQUILIBRIO ENTRE EL TRABAJO Y LA VIDA PERSONAL: REVISIÓN E INTEGRACIÓN DE LA LITERATURA

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    MARÍA CANDELA RODRÍGUEZ

    2017-01-01

    Full Text Available La sociedad y el mercado laboral han sufrido importantes cambios en los últimos años que gene- raron conflictos entre la vida laboral y personal de los individuos, causando resultados negativos en los mismos (insatisfacción y estrés y en las organizaciones (aumento de rotación y ausentismo. Actualmente la literatura no brinda conocimiento suficiente para orientar a empleadores y empleados sobre las acciones para evitar el conflicto trabajo-vida. El objetivo de este trabajo es integrar la teoría sobre estrategias individuales para lograr el equilibrio trabajo-vida, identificando sus efectos en los individuos y en la organización que los emplea. Para ello, se revisaron publicaciones en re- vistas prestigiosas del campo del Management, entre 2000-2015. Se concluye con una discusión sobre las implicancias para gestionar los Recursos Humanos.

  13. Variabilidad del contenido de humedad-equilibrio de la madera de diez especies comerciales para tres regiones del Perú

    OpenAIRE

    Rosales-Solórzano, Emer Ronald

    2015-01-01

    La investigación tuvo por objeto determinar el contenido de humedad-equilibrio (CHE) de la madera por año, época y estación en Puerto Maldonado y predicción anual para Huánuco y Lima. El método seguido fueron en base a los procedimientos de las normas ASTM, D – 2395 e INDECOPI-251 011, metodología que consistió en medir instantáneamente las probetas de madera y secar en estufa las mismas, que nos sirvió para determinar el CHE, peso actual (Pa) midiendo una vez por semana durante un año, calcu...

  14. Implicaciones de NAFTA, TLCUEM y de la integración de China a la OMC en el mercado de la berenjena: una perspectiva de equilibrio espacial

    OpenAIRE

    Guajardo, Ramon; Rios, Maricela

    2009-01-01

    Este artículo estudia el impacto de NAFTA, TLCUEM y de la integración de China a la OMC en el mercado mundial de la berenjena. Los impactos son medidos en términos de cambios en los flujos comerciales y en los precios. Se especificó y estimó un modelo de equilibrio espacial con precios endógenos y se simularon escenarios alternativos: con y sin la operación de los tratados y la integración de China a la OMC. Los resultados mostraron que la operación de estos tratados crea desviación de comerc...

  15. La transición de la teoría del equilibrio puntuado hacia una teoría de rango medio

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    Cachón, Vladimir

    2002-12-01

    Full Text Available The punctuated equilibrium theory is analysed as well as the causes of why at the present time it has become a middle-range theory although it was originally presented as a wide range evolution theory. The facts responsible for this transformation are studied. The article concludes with a vision of what is to be expected in the near future.

    Se analiza la teoría del equilibrio puntuado y las causas de que habiendo sido enunciada como una teoría evolutiva de amplio alcance en la actualidad sólo sea una teoría de aplicación limitada, o de rango medio. Se estudian los factores responsables de esta transformación y se concluye con una visión sobre lo que cabe esperar para el futuro próximo.

  16. fields

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    Brad J. Arnold

    2014-07-01

    Full Text Available Surface irrigation, such as flood or furrow, is the predominant form of irrigation in California for agronomic crops. Compared to other irrigation methods, however, it is inefficient in terms of water use; large quantities of water, instead of being used for crop production, are lost to excess deep percolation and tail runoff. In surface-irrigated fields, irrigators commonly cut off the inflow of water when the water advance reaches a familiar or convenient location downfield, but this experience-based strategy has not been very successful in reducing the tail runoff water. Our study compared conventional cutoff practices to a retroactively applied model-based cutoff method in four commercially producing alfalfa fields in Northern California, and evaluated the model using a simple sensor system for practical application in typical alfalfa fields. These field tests illustrated that the model can be used to reduce tail runoff in typical surface-irrigated fields, and using it with a wireless sensor system saves time and labor as well as water.

  17. Una propuesta de formación de precios para la economía ecológica, mediante un sistema de equilibrio general

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    Montoya Iván A.

    2008-12-01

    Full Text Available

    Los principales enfoques conceptuales en Economía Ambiental suelen provenir de orientaciones epistemológicas que privilegian el análisis de trade-off entre el empleo marginal de recursos y sus costos de recuperación; sin embargo, dificultan procesos de recurrencia o circularidad como la producción limpia o el empleo de subproductos en un sistema productivo complejo. La utilización de un modelo clásico para la determinación de precios en equilibrio general, originado por los trabajos de Piero Sraffa, puede constituirse en una interesante alternativa conceptual para concebir la formación de precios en un enfoque enriquecido y alterno, que permita incluir la problemática ambiental en el análisis económico, pues facilita la recolección de información sobre la realización de procesos y actividades con recurrencia. El objetivo del documento es proponer un sistema de precios en equilibrio general clásico y sugerir la valoración de bienes y servicios ambientales mediante el uso de rentas diferenciales. La metodología incluye revisión de fuentes bibliográficas, formulación de la pregunta de investigación, identificación de modelos alternativos teóricos relevantes a la pregunta y realización de una propuesta teórica en los términos del objetivo propuesto.

  18. ESTUDIO DEL EQUILIBRIO LÍQUIDO-LÍQUIDO DE BENCENO + (HEXANO, HEPTANO Y CICLOHEXANO CON EL LÍQUIDO IÓNICO 1-ETIL-3-METILIMIDAZOLIO ETILSULFATO A 308,15 K

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    Marlon Martínez Reina

    2011-12-01

    Full Text Available Se determinó el equilibrio líquido-líquido(ELL de los sistemas ternarios benceno+ (hexano, heptano y ciclohexanocon el líquido iónico 1-etil-3-metilimidazolioetilsulfato (EMIM-EtSO4 a 308,15K; la selectividad (S y el coeficiente dedistribución (β se calcularon desde losdatos experimentales que se utilizaronpara determinar la capacidad del líquidoiónico como solvente para la separacióndel aromático desde sus mezclas con hidrocarburosalifáticos. La región de inmiscibilidadaumentó en el siguiente orden:ciclohexano consistencia de los datos experimentalesdel ELL es evaluado usando la ecuaciónde Othmer-Tobias. La composición delas fases en equilibrio se correlacionócon los modelos para coeficientes de actividadNRTL y Uniquac.

  19. Evaluación de la marcha y el equilibrio como factor de riesgo en las caídas del anciano

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    Mayté Vera Sánchez

    2003-10-01

    Full Text Available Se realizó un estudio descriptivo en el que participaron 104 ancianos de un consultorio médico perteneciente al Policlínico Docente"Mario Escalona Reguera", a los cuales se les realizó una encuesta donde se evalúan varios parámetros relacionados con la marcha y el equilibrio, para determinar el riesgo de caídas según las variaciones encotradas. Se utilizó el método estadístico del Chi cuadrado para asociación de variables y el método porcentual. Encontramos que mientras más edad tienen los ancianos, más riesgo de caídas presentan y esto se relaciona con las alteraciones de la marcha y el equilibrio. Además, el riesgo de sufrir caídas fue más frecuente en el sexo femenino, y los factores de riesgo más frecuentes fueron la necesidad de usar los brazos para levantarse y sentarse, la necesidad del bastón para estar de pie, la marcha con talones separados y no levantar el pie completamente del suelo.A descriptive study of 104 older people from a physician´s office of "Mario Escalona Reguera" teaching polyclinics was performed. These aged persons were administered a survey to evaluate several parameters related to gait and balance, with the purpose of determining fall risks according to the variations found. Chi square statistical method for association of variables and the percentage method were used. We found that risk of falling increases with the age as a result of altered gait and balance. Besides, the risk of falling down was more common in females and the most frequent risk factors were the need of using arms to stand up and sit down and a stick to be on one´s feet, gait characterized by separated heels and not raising completely the feet when walking.

  20. Historical and contemporary trends in competitive balance in the Commonwealth Games. [Las tendencias históricas y contemporáneas en el equilibrio competitivo en los Juegos de la Commonwealth].

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    Girish Ramchandani

    2014-01-01

    Full Text Available Studies of competitive balance in sport have considered primarily professional leagues and team sports. This paper investigates trends in competitive balance in a multi-sport event context – the Commonwealth Games – using three distinct indicators. The investigation demonstrated that the Games have become significantly less competitive overall between 1930 and 2010 (p 0.10. Events contested by 'men only' were found to be the most balanced relative to both 'women only' and 'mixed / open' events across all indicators. Boxing and athletics emerged as the most balanced sports compared with diving, cycling, swimming and, to a lesser extent, weightlifting. The findings are of value to competition authorities to determine whether to implement corrective measures in order to maintain or improve competitive balance. Resumen Los estudios sobre equilibrio competitivo en deporte han considerado principalmente ligas profesionales y deportes de equipo. Esta investigación analiza las tendencias en el equilibrio competitivo en un contexto de un evento multideportivo: Los Juegos de la Commonwealth, empleando para ello tres indicadores diferentes. Así, los resultados muestran que el nivel competitivo de los Juegos ha decrecido globalmente entre 1930 y 2010 (p0.10. Los eventos en los que competían hombres únicamente han estado más equilibrados con respecto a los de mujeres o los mixtos, y este resultado se refleja en los tres indicadores. El boxeo y el atletismo han sido los deportes más equilibrados, comparados con los saltos de trampolín, el ciclismo, la natación y, en menor medida, la halterofilia. Estos resultados proporcionan una valiosa fuente de información para la gestión de los Juegos, en aras de implementar medidas correctivas para mantener o mejorar el equilibrio de la competición. Palabras clave: equilibrio competitivo; alto rendimiento; eventos multideportivos, incertidumbre en el resultado.

  1. Propiedades relacionales de las redes de colaboración y generación de conocimiento científico: ¿Una cuestión de tamaño o equilibrio?

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    Villanueva-Felez, África

    2014-12-01

    Full Text Available This article analyses the effect of networks of scientists on the quantity and quality of their academic output. Information on the characteristics of the networks comes from a questionnaire completed by 191 Spanish academic scientists working in the field of nanotechnology. The article considers the networks that these scientists establish with other individuals and through organizations and examines how the degree of embeddedness and nodal heterogeneity of these networks affects scientists’ output. The findings show that the balance achieved among members of a network –whether individual or organizational-- explains more about the quantity and quality of academic output, than the size of the network. Regardless of their size, more integrated and geographically balanced networks of individuals enhance academic production; additionally their geographic balance also serves to enhance the quality of the output. In the case of organizational networks with a well-balanced institutional diversity, there is a greater quantity of academic production, as opposed to those organizational networks characterized by a geographic balance.El artículo analiza la influencia de las redes de los investigadores en la cantidad y calidad de su producción de conocimiento científico, con datos obtenidos de un cuestionario, cumplimentado por 191 investigadores/académicos españoles especializados en nanotecnología. Se consideran las redes que los investigadores establecen con otros individuos y organizaciones y se examina el efecto de las propiedades relacionales de las redes de colaboración (grado de incrustación y heterogeneidad nodal en la producción científica, teniendo en cuenta el tamaño de la red. Se observa que el equilibrio en las redes personales y organizativas explica más la cantidad y la calidad de la producción científica que el tamaño de las redes. Las redes personales equilibradas en su fuerza y su diversidad geográfica facilitan la

  2. Las relaciones internacionales de la guerra civil siria a partir de un enfoque regional: hegemonía y equilibrio en Medio Oriente

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    Rafat Ahmed Ghotme Ghotme

    2015-06-01

    Full Text Available El propósito de este artículo es analizar la dimensión regional de la guerra civil siria a partir de los intereses de los principales Estados del Medio Oriente involucrados. A pesar de encontrar factores relacionados con la identidad o la ideología, tanto las acciones de los Estados tomados individualmente como los diferentes bloques establecidos actúan de acuerdo con la preservación o expansión del poder y sus intereses. Esta lógica se circunscribe en la teoría realista de relaciones internacionales y sirve como instrumento para abordar, a través del método del análisis de coyuntura, el comportamiento de los actores estatales y no estatales en la guerra civil siria como un intento por contener las amenazas a su seguridad en un entorno anárquico y un sistema regional competitivo e inestable, dejando a un lado las consideraciones morales. Mientras que algunos de ellos pueden estar buscando convertirse en líderes regionales, como Arabia Saudita o Turquía, otro grupo de actores, como Irán y Hezbollah, están empeñados en mantener un mínimo de equilibrio. La guerra Siria, en ese sentido, desempeña un rol clave para contener o expandir las aspiraciones de los Estados vecinos.

  3. Las relaciones internacionales de la guerra civil siria a partir de un enfoque regional: hegemonía y equilibrio en Medio Oriente

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    Rafat Ahmed Ghotme Ghotme

    2015-01-01

    Full Text Available El propósito de este artículo es analizar la dimensión regional de la guerra civil siria a partir de los intereses de los principales Estados del Medio Oriente involucrados. A pesar de encontrar factores relacionados con la identidad o la ideología, tanto las acciones de los Estados tomados individualmente como los diferentes bloques establecidos actúan de acuerdo con la preservación o expansión del poder y sus intereses. Esta lógica se circunscribe en la teoría realista de relaciones internacionales y sirve como instrumento para abordar, a través del método del análisis de coyuntura, el comportamiento de los actores estatales y no estatales en la guerra civil siria como un intento por contener las amenazas a su seguridad en un entorno anárquico y un sistema regional competitivo e inestable, dejando a un lado las consideraciones morales. Mientras que algunos de ellos pueden estar buscando convertirse en líderes regionales, como Arabia Saudita o Turquía, otro grupo de actores, como Irán y Hezbollah, están empeñados en mantener un mínimo de equilibrio. La guerra Siria, en ese sentido, desempeña un rol clave para contener o expandir las aspiraciones de los Estados vecinos.

  4. Beneficios del Tai Chi Chuan en la osteoartritis, el equilibrio y la calidad de vida (Tai Chi Chuan benefits on osteoarthritis, balance and quality of life

    Directory of Open Access Journals (Sweden)

    Pedro Jesús Jiménez-Martín

    2013-04-01

    Full Text Available Objetivo: Este trabajo hace una revisión de los estudios científicos realizados a nivel internacional con el fin de actualizar el conocimiento sobre cuáles son los beneficios que aporta la práctica del Tai Chi Chuan (TCC sobre la osteoartritis de rodilla (OR, el equilibrio, el miedo a las caídas y la calidad de vida. Método: Se realizó una búsqueda bibliográfica sobre ocho bases de datos internacionales (Medline-Pubmed, Scirus, Pascal, ScienceDirect, SportDiscus, Science Citation Index, BIOSIS y PsycINFO hasta abril del año 2012. Resultados: El número total de estudios analizados fue de 74, de los cuales 13 corresponden a revisiones sistemáticas y 61 a estudios específicos (42 ensayos aleatorios controlados (EAC y 19 ensayos no controlados (ENC. En particular se analizaron 11 estudios con relación a la osteoartritis de rodilla (7 EAC y 4 ENC, 32 sobre el equilibrio-miedo a las caídas (26 EAC y 6 ENC, y 30 sobre calidad de vida (18 EAC y 12 ENC Conclusión: Los efectos de TCC sobre la OA son contradictorios, aunque se observa una tendencia positiva respecto al control de dolor y la mejora en la funcionalidad física. Respecto a los efectos sobre el equilibrio-miedo a la caída se ha registrado una mejora significativa en el equilibrio estático y dinámico, y en la confianza respecto al miedo a la caída. Con relación a la calidad de vida la práctica del TCC aporta mejoras en las dimensiones de bienestar emocional, percepción de sí mismo, bienestar corporal. Estos resultados obtenidos deben ser tomados con cierta precaución dado que gran número de los estudios examinados muestran carencias metodológicas en cuanto al diseño de investigación (muestras reducidas, carencias en los criterios de inclusión y de exclusión de los participantes, deficiencias en los análisis estadísticos, carencias en la estandarización de la medición de resultados, etc. y la información específica respecto a las condiciones del programa de

  5. La enseñanza de la química vista desde la perspectiva de Jensen: Una red conceptual sobre equilibrio químico

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    Ángela Castrillón Univio

    2009-10-01

    Full Text Available Este trabajo propone una red conceptual basado en el concepto generador equilibrio químico, para la enseñanza de la química desde la propuesta epistemológica de Jensen W. B con el objetivo de integrar la historia y la epistemología en la realización posterior de una propuesta de diseño curricular la cual está definida en el marco de la ley general de educación Ley 115 de 1994, para tal propósito se toma como referencia bibliográfica los postulados de epistemólogos reconocidos como Popper, Lakatos y Khun, luego se describe las concepciones de enseñanzaaprendizaje que posee el profesor como producto de su visión de ciencia, finalmente como éstas se articulan, con la propuesta de Jensen W. B y en el diseño curricular.

  6. Equilibrio trabajo-familia, apoyo familiar, autoeficacia parental y funcionamiento familiar percibidos por funcionarios públicos de Chile Work-Family Balance, Family Support, Parental Self Efficacy and Perceived Family Functioning in a Chilean Public Workers

    Directory of Open Access Journals (Sweden)

    Elizabeth Riquelme Orellana

    2012-06-01

    Full Text Available Se analiza la relación entre Equilibrio trabajo-familia, Apoyo familiar, y Autoeficacia parental en funcionarios públicos, determinado las diferencias entre hombres y mujeres. A 181 funcionarios profesionales les fueron aplicados tres instrumentos de medición de las variables referidas. Se observa que existen diferencias estadísticamente significativas en el nivel de equilibrio trabajo-familia entre hombres y mujeres, obteniendo un mayor equilibrio las mujeres. Por otra parte no se encontró diferencias en apoyo familiar, autoeficacia parental y en funcionamiento familiar. En cuanto a la relación entre dichas variables se encontró una relación estadísticamente significativa entre Apoyo familiar y autoeficacia parental (r=-0,333; pIt is analyzed the relationship between work-family balance, family support, parental self-efficacy and public officials, given the differences between men and women. A 181 professional staff We applied three instruments measuring variables related. It is noted that there were significant differences in the level of work-family balance among men and women, giving women a better balance. On the other hand there was no difference in family support, parental self-efficacy and family functioning. Regarding the relationship between these variables was found a statistically significant relationship between family support and parental self-efficacy (r =- 0.333, p <0.01 between family support and family functioning (r = 0.734, p <0.01, work-family balance and parental self-efficacy (r = 0.275, p<0.01 and between parental efficacy and family functioning (r =-0.276, P <0.01.

  7. Equilibrios ácido-base. Aspectos teóricos. ¿Es posible la neutralización cuantitativa de dos protolitos débiles? Estudio del caso ácido bórico-amoníaco.

    OpenAIRE

    Milla González, Miguel

    2016-01-01

    Mediante la combinación de los balances de masa y las constantes de equilibrio del sistema, se encuentra la función y=f(x) [y = cantidad valorada del ácido débil y x la cantidad añadida de la base débil]. Se representa dicha función y se calcula su límite cuando x tiende a infinito para comprobar que no es posible la valoración (neutralización cuantitativa) del ácido bórico con la base amoníaco.

  8. The sterility of equilibrium economics: an aspect of sociology of science La esterilidad de la economía del equilibrio: un aspecto de la sociología de la ciencia

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    Bhatt V. V.

    2000-06-01

    Full Text Available This paper shows that economic science is yet to reach maturity and that equilibrium theory does not grasp actual economic relationships,and is sterile for policy making. It analyses the creation of castsamong economists, the impossibility of formalizing all economic phenomena in terms of individual optimization, and the ideological biases of scientific work. It suggests the need to reassess the basic hypothesis of the general equilibrium approach and to rebuild the analytical framework of economics. Based upon Krishnamurti "ephilosophy, it shows that the main thrust of human behavior is notselfishness but envy, and that this motivation weakens the traditional theory of individual and firm behavior.Este articulo muestra que la ciencia economica no ha alñcanzado la madurez que la la teoria del equilibrio no capta las relaciones economicas reales y es esteril para formular politicas ecopnomicas. Analiza la formacion de castas entre los economistas, la imposibilidad de formalizar todos los fenomenso economicos en terminos de optimizacion individual y los sesgos ideologicos del trabajo cientifico. Indica la necesidad de replantear las hipotesis basicas del enfoque del equilibrio general y de reconstruir el aparato analitico de la economia. Con base en la filosofia de Krishnamurti, muestra que la fuerza motriz de la conducta humana es la envidia y no el egoismo , y que esta motivacion resta validez a la teoria tradicional del comportamiento de los individuos y de las empresas.

  9. Insuficiencia respiratoria aguda

    OpenAIRE

    Gutiérrez Muñoz, Fernando R.

    2010-01-01

    La función respiratoria básica es el intercambio gaseoso de oxígeno y dióxido carbono; lo que implica un perfecto equilibrio y control entre los componentes del sistema respiratorio. a insuficiencia respiratoria aguda (IRA) es la incapacidad del sistema respiratorio de cumplir su función básica, que es el intercambio gaseoso de oxígeno y dióxido de carbono. Basic respiratory function is gas exchange of oxygen and carbon dioxide, which implies a perfect balance and control between the compo...

  10. Relación entre indicadores de la capacidad de equilibrio y el control de los envíos en lanzadores juveniles de béisbol / Relation between balance ability indicators and pitch control in junior baseball pitchers

    Directory of Open Access Journals (Sweden)

    Uverlandi Luis-Quintana

    2016-07-01

    Full Text Available Resumen Se investigó la relación entre el equilibrio y el control de los envíos en lanzadores juveniles de béisbol de la Escuela de Iniciación Deportiva Escolar Cerro Pelado de Camagüey, Cuba. Se empleó la Observación para establecer los resultados del control de los envíos y también una batería de pruebas compuesta por el Test de Romberg Complejo II, la Prueba ortostática y la Prueba de reacciometría simple inespecífica; resultados que fueron correlacionados con la efectividad de diez lanzadores seleccionados de forma aleatoria. Los resultados fueron procesados con métodos matemático-estadísticos con el empleo del paquete SPSS 12.0 para Windows. Las insuficiencias detectadas en la capacidad de equilibrio y control en los envíos de los atletas sirvieron de base para establecer la correlación entre ambas variables. Los resultados constituyen un punto de partida para realizar pruebas de equilibrio que brinden una idea aproximada de la efectividad de los movimientos, sin necesidad de hacer pruebas para lanzamientos que resultan más complejas; además, porque no es posible utilizar solamente la Prueba ortostática con este fin. Abstract A research was conducted on the relation between balance and pitch control in junior baseball pitchers of the Sports Introduction School Cerro Pelado in Camagüey, Cuba. The Observation method was used to establish the results of pitch control, and a set of tests composed by the Romberg complex text II, the orthostatic test, and a non-specific simple reacciometry test; the results were correlated with the effectiveness of ten pitchers selected at random. They were processed with the Mathematical-Statistical method by means of the SPSS 12.0 package for Windows. The inadequacies detected in the balance ability and pitch controlof the athletes served as the basis for correlating both variables. These results constitute the starting point for new balance tests that may show an approximate idea of

  11. Choques exógenos y política fiscal en un modelo de equilibrio general dinámico estocástico (DSGE: una aplicación para una economía emergente

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    Jesús Botero

    2013-12-01

    Full Text Available En este artículo se utiliza un modelo de equilibrio general dinámico estocástico (DSGE paraevaluar el impacto de choques de oferta (productividad y demanda (comercio externo sobre eldesempeño económico. En particular, este trabajo analiza el impacto de las políticas fiscales, específicamente el efecto del gasto público en determinados entornos económicos, como el colombiano.Los ejercicios realizados muestran que en un modelo de economía abierta, una políticaexpansiva de gasto público incrementa en el corto plazo el empleo y el producto, pero se incurre en un costo futuro, que parece sugerir un impacto superior al beneficio alcanzado en el corto plazo.

  12. Niveles de plomo en sangre en niños de 8 a 10 años y su relación con la alteración en el sistema visomotor y del equilibrio

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    Azcona-Cruz María Isabel

    2000-01-01

    Full Text Available OBJETIVO: Identificar si existe una asociación negativa entre los niveles de plomo en sangre y la coordinación visomotora y el equilibrio de escolares. MATERIAL Y MÉTODOS: Se realizó un estudio transversal en 255 niños de 8 a 10 años de edad, que asistían a escuelas del Sector 1 del Instituto de Educación Pública del Estado de Oaxaca, durante noviembre y diciembre de 1998. Se les aplicaron las pruebas de evaluación de la percepción visual de Frostig y la subescala de equilibrio Frostig Movement Skills Test Battery y se les tomó una muestra de sangre para la determinación de plomo por medio de espectrometría de absorción atómica. Asimismo, se aplicó un cuestionario sociodemográfico y se evaluó la historia de salud del niño. Se relacionó el nivel de plomo sanguíneo con los resultados de las pruebas de percepción visual y del equilibrio mediante modelos de regresión múltiple. Se usó la técnica de simulaciones de Montecarlo para probar el efecto del plomo dentro del modelo. RESULTADOS: La media geométrica de las concentraciones de plomo en sangre fue de 11.5 µg/dl (DE geométrica= +6.3, -5.2. El nivel de plomo se relacionó significativamente con el cociente de integración visomotora (p>0.042. Este disminuye 1.78 (IC 95% -3.51, -0.06 puntos por cada incremento de 10 µg/dl en los niveles de plomo en sangre del niño. De las pruebas que constituyeron este cociente, sólo se relacionó significativamente el plomo con la de coordinación ojo-mano (p=0.045 y de relaciones espaciales (p=0.039. El ingreso familiar también se relacionó significativamente con el cociente de integración visomotora, a mayor ingreso los resultados en las pruebas del niño fueron más altos. Sólo 3.1% de los niños obtuvieron puntuaciones consideradas clínicamente anormales. No se encontró una relación significativa entre el plomo y el cociente de la respuesta motriz reducida, el cociente de percepción visual general y las pruebas de

  13. El principio de la responsabilidad civil objetiva limitada: un elemento de equilibrio sistémico que no contradice al denominado principio de la reparación integral del daño

    Directory of Open Access Journals (Sweden)

    Gian Franco Rosso Elorriaga

    2014-06-01

    Full Text Available La tendencia moderna a objetivar la responsabilidad civil ha generado diferentes incoherencias sistémicas que exigen la introducción de elementos de equilibrio entre la responsabilidad subjetiva y la responsabilidad objetiva. Ante la permanente infracción al principio de la tipicidad, se propone como vía de equilibrio el reconocimiento del principio según el cual no puede haber responsabilidad objetiva sin limitación cuantitativa de la indemnización. Sin embargo, este principio entraría aparentemente en contradicción con otro, denominado principio de la reparación integral del daño. El artículo analiza dicha posible contradicción desde el fundamento moral de ambas clases de responsabilidad, así como del principio de la reparación integral del daño. Además, profundiza la problemática a partir de su elemento esencial, como es el daño resarcible, de modo de verificar qué elementos puede aportar a este aquel principio. En esta perspectiva, se estudia si tiene verdaderamente un carácter normativo, y qué cambios a su respecto produce su reconocimiento expreso a nivel legal o constitucional. Por último, se trata el principio de la reparación integral bajo un concepto distinto al tradicional y que ha venido sosteniéndose en los últimos años, a fin de confrontarlo con la citada contradicción. Al término del artículo, se sintetizan las conclusiones alcanzadas, las cuales concuerdan con la inexistencia de la contradicción entre el principio según el cual no hay responsabilidad objetiva sin limitación cuantitativa y el principio de la reparación integral del daño.

  14. El principio de la responsabilidad civil objetiva limitada: un elemento de equilibrio sistémico que no contradice al denominado principio de la reparación integral del daño

    Directory of Open Access Journals (Sweden)

    Gian Franco Rosso Elorriaga

    2014-07-01

    Full Text Available La tendencia moderna a objetivar la responsabilidad civil ha generado diferentes incoherencias sistémicas que exigen la introducción de elementos de equilibrio entre la responsabilidad subjetiva y la responsabilidad objetiva. Ante la permanente infracción al principio de la tipicidad, se propone como vía de equilibrio el reconocimiento del principio según el cual no puede haber responsabilidad objetiva sin limitación cuantitativa de la indemnización. Sin embargo, este principio entraría aparentemente en contradicción con otro, denominado principio de la reparación integral del daño. El artículo analiza dicha posible contradicción desde el fundamento moral de ambas clases de responsabilidad, así como del principio de la reparación integral del daño. Además, profundiza la problemática a partir de su elemento esencial, como es el daño resarcible, de modo de verificar qué elementos puede aportar a este aquel principio. En esta perspectiva, se estudia si tiene verdaderamente un carácter normativo, y qué cambios a su respecto produce su reconocimiento expreso a nivel legal o constitucional. Por último, se trata el principio de la reparación integral bajo un concepto distinto al tradicional y que ha venido sosteniéndose en los últimos años, a fin de confrontarlo con la citada contradicción. Al término del artículo, se sintetizan las conclusiones alcanzadas, las cuales concuerdan con la inexistencia de la contradicción entre el principio según el cual no hay responsabilidad objetiva sin limitación cuantitativa y el principio de la reparación integral del daño.

  15. Establecimiento de una red de equilibrios biológicos en ecosistemas con presencia de pinsapo (Abies pinsapo Boiss. en Andalucía.

    Directory of Open Access Journals (Sweden)

    Navarro Cerrillo, R. M.

    2004-12-01

    Full Text Available In 2001, the Consejería de Medio Ambiente of the Junta de Andalucía established a Monitoring Network on ecosystems of Abies pinsapo Boiss.for evaluating the phytosanitary state in the natural range areas of A. pinsapo in the Iberian Península: Sierra de las Nieves (Málaga, Spain, Sierra de Grazalema (Cadiz, Spain and Los Reales de Sierra Bermeja (Málaga, Spain. This network is based on a 1 x 1 Km grid established throughout the forest stands where Abies pinsapo is present, given by the Mapa Forestal de España (Spanish land cover map, RUIZ DE LA TORRE, 1990. The Network has been constructed from 35 sample plots, which will be visited annually (in summer in order to assess the state of trees. This article describes the network design process and the main results from the first campaign of sampling.

    [fr]
    En mai 2001, la Consejería de Medio Ambiente-Junta de Andalucía a mis sur pied un Réseau pour la surveillance systématique et multitemporelle de l'état de santé et vitalité des forets de Abies pinsapo Boiss. dans ses aires de répartition naturelle dans la Péninsule Ibérique: Sierra de las Nieves (Málaga, Espagne, Sierra de Grazalema (Cádiz, Espagne et Los Reales de Sierra Bermeja (Málaga, Espagne. Cet inventaire a été réalisé à partir d'un réseau d'échantillonnage systématique selon un maillage de 1 x 1 kilomètres couvrant la surface des forêts avec présence de Abies pinsapo, d'après la Mapa Forestal de España (Carte Forestière Espagnole, RUIZ DE LA TORRE, 1990. Après Rétablissement, l'inventaire a été constitué par 35 parcelles d'observation, qui seront visitées annuellement (en été pour évaluer l'état des arbres. Cette note présente le dessin de ce réseau et les résultats de la première campagne de terrain.
    [es]
    En la primavera del año 2001, la Consejería de Medio Ambiente de la Junta de Andalucía estableció una Red de Equilibrios Biol

  16. La inversión extranjera directa y las exportaciones en Tailandia. Pruebas de causalidad de Granger y equilibrio general Foreign direct inverstment and exports in Thailand. granger's causality tests and general equilibrium

    Directory of Open Access Journals (Sweden)

    De Lombaerde Philippe

    1996-12-01

    Full Text Available Los autores investigan la causalidad entre inversión directa y las exportaciones en el caso de Tailandia, un país caracterizado por un rapido crecimiento económico y de exportaciones, y por sus entradas de capital extranjero relativamente importantes. Sus resultados en prueba de causalidad de Granger contradicen los resultados de un estudio de equilibrio general, utilizando datos sobre la inversión japonesa en Tailandia. Los autores apuntan al riesgo de utilizar una sola metodología y sugieren razones por ambigüedad de los resultados.The authors investigate the FDI -export causality in the case of
    Thailand, a country characterized by rapid economic and exports growth, and relatively important incoming FDI flows , Their results from Granger causality tests contradict with those from a general-equilibrium study using data on Japanese FDI in Thailand. The authors indicate the risk of using single methodologies and suggest reasons for the ambiguous
    results.

  17. Política exterior ecuatoriana durante la guerra del Pacífico: un análisis desde la óptica de los equilibrios de poder en la región latinoamericana

    Directory of Open Access Journals (Sweden)

    Claudio Andrés Tapia Figueroa

    2016-01-01

    Full Text Available Resumen La guerra del Pacífico (1879-1884 que enfrentó a Perú y Bolivia contra de Chile, representa un conflicto armado marcado por las políticas realistas de imponer el interés nacional, frente a otros Estados, alterando el equilibrio político regional, bajo la justificación de las reivindicaciones territoriales. Esta política no sólo afectó a los beligerantes, sino que a otros países que pudieron sumarse en la confrontación buscando cambiar su status quo. Ecuador representa esta consideración, en cuanto a que su participación pudo consolidar su frontera sur con Perú, pendiente desde de la emancipación. ¿Fue la debilidad política interna la que no permitió concretar una posible intervención? En las siguientes páginas se estudiará este proceso histórico, desde la óptica del realismo clásico presente en las relaciones internacionales, donde el escenario interno de un país, es determinante en la proyección de su política exterior.

  18. El totus orbis y el ius gentium en Francisco de Vitoria: el equilibrio entre tradición e innovación | Totus orbis and ius gentium in Francisco de Vitoria: the balance between tradition and innovation

    Directory of Open Access Journals (Sweden)

    Encarnacion Fernandez Ruiz-Galvez

    2017-06-01

    Full Text Available Resumen: El artículo examina dos conceptos centrales en la doctrina internacional de Vitoria: la idea de orbe como comunidad universal de todos los hombres y de todos los pueblos unidos por el vínculo de la común naturaleza humana, y el ius gentium como Derecho universal de la humanidad que rige en todo el orbe. El trabajo destaca el equilibrio entre tradición (universalismo cosmopolita de raíces estoicas y cristianas y iusnaturalismo clásico e innovación (ideas de derechos naturales, de igualdad e independencia de todos los pueblos y concepción de la comunidad internacional como una comunidad jurídica y la antropología no individualista que subyace a la doctrina internacional de Vitoria.   Abstract: The article analyzes two central concepts in the international doctrine of Vitoria: the idea of the orb as a universal community of all human beings and of all peoples united by the bond of common human nature, and ius gentium as the universal law of humanity rules around the world. The work highlights the balance between tradition (cosmopolitan universalism of Stoic and Christian roots and classical natural ius and innovation (ideas of natural rights, equality and independence of all peoples and conception of the international community as a legal community and the non-individualistic anthropology that underlies the international doctrine of Vitoria.

  19. Conformational equilibrium and effects of some 2-mono substituted cyclohexanone substituents; Equilibrio conformacional e efeitos dos substituintes de algumas cicloexanonas 2-monossubstituidas

    Energy Technology Data Exchange (ETDEWEB)

    Basso, Ernani A [Universidade Estadual de Maringa, PR (Brazil); Trevisan, Paulo S [Universidade Estadual de Campinas, SP (Brazil). Inst. de Quimica; Lambert, Joseph B [Northwestern Univ. (United States)

    1992-12-31

    This work re-evaluates, using a high-field device (400 MHz) and the Eliel method, the 2-halo substituted cyclohexanone conformational equilibrium, which applies the chemical shift values ({delta}) and the {alpha} proton coupling constants (J). {sup 13} C NMR spectra were also obtained for investigation of the substituent effects on the cyclohexanone ring carbons chemical shift, since the few works treating the subject are at most incomplete. The results are compared with those obtained for the 2-methoxy cyclohexanone previously described, and reproduced in this work 12 refs., 4 figs., 3 tabs.

  20. Caracterización hidroquímica y análisis de los estados de equilibrio termodinámico en aguas termominerales de Alhama de Murcia (Murcia, Espana

    Directory of Open Access Journals (Sweden)

    Padilla Benítez, A.

    1993-04-01

    contaminación agrícola y la existencia de posibles mineralizaciones. Existen procesos de cambio de bases. Los estados de equilibrio termodinámico en las condiciones de surgencia, estudiados mediante el programa SOLMINEQ. 88, indican que todas las muestras están saturadas en cuarzo, calcedonia y albita, casi todas en calcita, aragonito, dolomita, yeso, barita y magnesita, y todas subsaturadas en cristobalita,anhidrita y fluorita. Las temperaturas de base obtenidas mediante diferentes geotermómetros cubren una amplia gama; los geotermómetros calcita-dolomita y anhidrita- fluorita son aplicables sólo a dos muestras con resultados anómalos. La modelización de los índices de saturación a temperaturas crecientes muestra un equilibrio del cuarzo, calcedonia, albita, sanidina, yeso, anhidrita, gibbsita y halloisita entre los 80-110 ºC. La dispersión de valores indicada por ambas metodologías se debería a fenómenos de dilución por mezcla de aguas más superficiales, efectos de reequilibrio entre los minerales y el agua, y pérdida de CO2. La temperatura y composición química de las aguas indican que existe una anomalía térmica importante relacionada con la actividad tectónica del área.

  1. Role of Exchange Equilibria in Structural Chemistry; Role des Equilibres d'Echange en Chimie Structurale; Rol' ravnovesiya obmena v strukturnoj khimii; Papel de los Equilibrios de Intercambio en Quimica Estructural

    Energy Technology Data Exchange (ETDEWEB)

    Van Wazer, J. R.; Moedritzer, K. [Monsanto Company, St. Louis, MI (United States)

    1965-10-15

    revanche, de vastes parties de la chimie inorganique n'ont jamais pu faire l'objet de descriptions parce que les echanges que subissent les molecules sont si rapides que ces molecules ne peuvent etre separees. Toutefois, elles peuvent etre identifiees et dosees par des methodes physiques (par exemple la RMN) ayant des constantes de temps courtes, si les donnees obtenues font l'objet d'un traitement mathematique approprie, ce traitement etant assez complexe pour justifier l'emploi d'un ordinateur a grande vitesse [6, 16]. Les points passes en revue ont ete illustres par des exemples de systemes [2, 12, 24, 28] tires des travaux recents de l'auteur. Outre les etudes d'equilibre, l'attention de l'auteur s'est portee sur la cinetique des processus d'echange [26, 27]. Il a expose plusieurs theoremes de caractere general qui sont utiles pour prevoir les genres et quantites de produits [6, 18]. (author) [Spanish] Si bien gran parte de los estudios realizados hasta el presente sobre las reacciones de intercambio se han dedicado a la introduccion de sustituyentes monofuncionales en atomos o partes de molecula polifuncionales, tambien las moleculas complicadas pueden sufrir un intercambio de partes, para dar una distribucion equilibrada de moleculas de diversos tamanos y formas. En una seria de trabajos originados en el laboratorio Monsanto Co. (veanse las refs.[1-34] al final de los resumenes), durante 1964 y 1965, se describio el empleo de la resonancia magnetica nuclear de elevado poder de resolucion para estudiar esas mezclas en equilibrio. Los sistemas asi estudiados incluyen varias familias nuevas de compuestos, y los tipos de productos resultantes de los intercambios se han definido y sus cantidades se han determinado en funcion de un pequeno numero de constantes de equilibrio. SeJia empleado un nuevo enfoque matematico - la teoria del grafico estocastico [6] - para establecer la ferma y el numero minimo de constantes de equilibrio que vinculan las estructuras aciclicas y las

  2. Thermodynamic study of phase equilibria in petroleum separation plants; Estudo termodinamico do equilibrio de fases em plantas de separacao de petroleo

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Ciro Rodolfo Santos; Duarte, Lindemberg de Jesus Nogueira [Universidade Federal do Rio Grande do Norte (UFRN), Natal, RN (Brazil); Santos, Luiz Carlos Lobato [Universidade Federal da Bahia (UFBA), BA (Brazil)

    2012-07-01

    Through a thermodynamic approach of liquid-vapor separation it is possible to provide for a given load, of known composition and given temperature and pressure conditions, which are the volumes and the compositions of liquid and vapor phases in equilibrium. In this sense, the aim of this work is to analyze the separation conditions of the fluids produced in the well 1-FMO-001-BA, belonging to the Field School Project (ANP / UFBA), through a thermodynamic approach of phase equilibrium. This Well is characterized by being in an advanced stage of exploration with low oil and high gas production. Initially, the overall composition of the gas produced from the 1-FMO-001-BA was quantified by gas chromatography and its composition was similar to a typical natural gas found in the Reconcavo's basin. Then, the equilibrium constants were determined by Wilson empirical correlation, which could enable the determination of the dead oil composition. This oil showed low concentration of light hydrocarbons (e.g., methane, etc.) and moderate concentrations of heavy components (e.g., C{sub 10} {sub +}). Moreover, the original composition of the fluid that reaches the separator vessel had a similar chemical composition to the outlet gaseous stream of the separator vessel, proving that the Fazenda Mamoeiro's reservoir is classified as a gas reservoir. Finally, it was determined the relative density of the gas ({gamma} g = 0.8264), the specific gravity of the dead oil ({gamma} {sub o} = 0.7542), the API gravity (56.13) and gas-oil ratio (GOR 950.98 m{sup 3}std / m{sup 3}std), which are consistent with the data provided by PETROBRAS. (author)

  3. Plasma-Column Equilibrium in Tokamak-5; L'Equilibre d'une Colonne de Plasma dans l'Installation Tokamak-5; Issledovanie ravnovesiya plazmennogo shnura na ustanovke Tokamak-5; El Equilibrio de una Columna de Plasma en la Instalacion 'Tokamak-5'

    Energy Technology Data Exchange (ETDEWEB)

    Muhovatov, V. S. [Institut Atomnoj Ehnergii, Im. I.V. Kurchatova, Moskva, SSSR (Russian Federation)

    1966-04-15

    This paper, which is a continuation of work done by Grigorovich and Mukhovatov, is devoted to an investigation of the conditions of equilibrium of the plasma column in Tokamak-5. This equipment has the following parameters: large radius of the copper casing R = 62. 5 cm, small radius b = 25 cm, small radius of the liner = 20 cm, radius of the opening in the diaphragm = 15 cm (the centre of the opening in the diaphragm and the centre of the cross-section of the casing coincide), intensity of the longitudinal magnetic field B{sub 0} = 6 to 12 kOe and current in the plasma J = 15 to 20 kA, The tests were carried out at an initial hydrogen pressure of (1.8 to 5.0) x 10{sup -4} Torr. Between the casing and the liner were placed conductors, used to set up within the chamber a transverse magnetic field B{sub z} varying synchronously with the discharge current. Grigorovich and Mukhovatov had demonstrated qualitative agreement of experimental results with the hypothesis that the column is maintained in equilibrium by the copper casing, and had shown that the average electrical conductivity of the plasma over the cross-section of the column reaches its maximum if by means of the transverse field B{sub z} the column is arranged concentrically with the opening in the diaphragm. The present paper shows that in most discharge regimes there is good quantitative agreement between the experimental data and the theory of column equilibrium within the conducting casing. However, in a number of discharge regimes (with low initial gas pressures and high values of displacement {Delta}{sub B} = b{sup 2}B{sub z}c/2J directed towards the inner wall of the torus) there is a certain discrepancy between theory and experiment. An attempt was made to assess to what extent the process of cutting off drift current by the conducting diaphragm contributes to maintaining equilibrium of the column in Tokamak. For this purpose the diaphragm was cut into six segments isolated from each other. During a

  4. Impuestos al capital y al trabajo en Colombia: un análisis mediante equilibrio general computable Effect of Taxes on Capital and Labor in Colombia: A Computable General Equilibrium Analysis

    Directory of Open Access Journals (Sweden)

    Jesús Botero Garcia

    2011-10-01

    Full Text Available Mediante un modelo de equilibrio general computable, calibrado para Colombia, se analiza el impacto de diversas políticas económicas, que afectan el precio relativo de los factores productivos. Se concluye que los estímulos a la inversión, que pueden interpretarse como acciones que disminuyen el precio del capital, propician sin embargo la acumulación de capital, y por esa vía, incrementan la productividad del trabajo, generando efectos positivos netos sobre el empleo. La eliminación de los aportes parafiscales, por su parte, genera una reducción en el costo del trabajo, pero su efecto global sobre el empleo es compensado parcialmente por las acciones fiscales tendientes a generar rentas alternativas que permitan mantener los beneficios asociados a esos aportes. Se sugiere que el esquema ideal sería aquel que establece estímulos a la inversión, focalizados hacia sectores intensivos en empleo, al tiempo que crea redes de protección social adecuadas, para enfrentar los problemas asociados a la pobreza.   Abstract Using a computable general equilibrium model, calibrated for Colombia, it is analyze the impact of various economic policies, which affect the relative price of production factors. The results concluded that the incentives for investment, which can be interpreted as actions that decrease the cost of capital, however lead to the accumulation of capital, and thereby increase the productivity of labour, generating net positive effects on employment. The Elimination of the payroll taxes, for its part, generates a reduction in the cost of labour, but their overall effect on employment is partially offset by the tax measures designed to generate alternative income to keep the benefits associated with these contributions. Finally the suggestion is that the ideal scheme would be one that provides incentives for investment, focused towards employment-intensive sectors, at the time that creates networks of social protection appropriate

  5. Propuesta de enseñanza de equilibrio de cuerpo rígido por la acción de fuerzas coplanares con el uso de la geometría plana en el curso de Estática, de la Institución universitaria Pascual Bravo

    OpenAIRE

    Giraldo García, Jorge Iván

    2014-01-01

    Resumen: La propuesta de enseñanza del equilibrio de cuerpo rígido con el uso de la geometría plana para la asignatura Estática que se dicta en la Institución universitaria Pascual Bravo de Medellín, está enfocada en las teorías de aprendizaje significativo. Pretende con la ayuda de la geometría mejorar la comprensión de los conceptos que se deben aprender en la asignatura, como alternativa al uso matemático, como usualmente la enseñan los libros guía. El método descansa en los seis princ...

  6. Gas geochemistry of Los Humeros geothermal field, Mexico; Geoquimica de gases del campo geotermico de Los Humeros, Puebla, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Barragan R, Rosa Maria; Arellano G, Victor M; Nieva G, David; Portugal M, Enrique; Garcia G, Alfonso; Aragon A, Alfonso [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico); Torres A, Ignasio S [Centro de Investigacion en Energia, Temixco, Morelos (Mexico); Tovar A, Rigoberto [Comision Federal de Electricidad, Los Humeros, Puebla (Mexico)

    1999-12-01

    Gas data of Los Humeros geothermal field were analyzed. A new method, which is based on the Fischer-Tropch reactions and on the combined pyrite-magnetite mineral equilibrium, was used. Reservoir temperature and reservoir excess steam were estimated for the starting stage of the field by using early data taken from producing wells at controlled conditions. The same parameters were also obtained for the present stage by using 1997 gas data. Reservoir temperatures ranged from 275 and 337 Celsius degrees and positive values for reservoir excess steam fractions were obtained for the starting stage. For well H-1 no excess steam was found since this well was fed by the shallower liquid-dominated reservoir. Results for 1997 showed lower scattering compared to early data and the possible occurrence of a heating process in the shallower stratum which could due to exploitation. [Spanish] En este articulo se presenta un analisis de datos de la fase gaseosa producida por pozos productores del campo geotermico de Los Humeros mediante un metodo que considera el equilibrio de la reaccion de Fischer-Tropsh y el equilibrio de minerales pirita-hematia y pirita-magnetita. Este metodo provee la temperatura del yacimiento y el exceso de vapor presente en la descarga total de los pozos. Los resultados se discuten tanto para el estado inicial del yacimiento utilizando los primeros datos de produccion en los que el flujo del pozo estuvo controlado y los obtenidos en 1997 que representan el estado actual del yacimiento. En el estado inicial se estimaron temperaturas de yacimiento de entre 275 y 337 grados Celsius y excesos de vapor positivos, con excepcion del pozo H-1 que se alimenta del estrato somero dominado por liquido. Los resultados obtenidos para 1997 muestran una dispersion menor y la probable ocurrencia de un proceso de calentamiento del estrato somero propiciado por la explotacion.

  7. Modelización geoquímica directa métodos teóricos y numéricos aplicados al cálculo del equilibrio químico, transferencia de masa y caminos de reacción en procesos de interacción agua-roca

    Directory of Open Access Journals (Sweden)

    Femández Díaz, A. M.

    1994-12-01

    Full Text Available This work tackles the rock-wa:er interaction modelling by Direct Modelling (DM, and more specifically the Modelling of the Reaction Paths (MRP. This modelling quantitatively analizes the evolution of the system towards the total equilibrium through consecutive states of partial equilibrium based on the progress reaction variable, and requires the definition of the irreversible processes of the reacting system, the reversible processes of the equilibrium system and the progress reaction variable. Calculations require the relation of the mass balance equations of each element, the mass action law equations for each species, as well as the equations of mass balance of hydrogen, oxygen, charge balance and the conservation of electrons or constant mass according to the code to be used. The thermodynamic properties of the system are tackled according to the ionic association (Debye-Huckel or to the specific interactions (Pitzer coefficient, and the chemical equilibrium by Gibb's free energy method or by the approximation method of the equilibrium constant. Based on the numeric resolutions used by the codes, three groups of codes have been generated. WATEQ series, which uses the successive approximation numeric method, MINEQL series, that uses the Newton-Raphson method and PATH series which directly integrates the differential equations. One or other code family is applied according to the specific characteristics of the problem. The direct modelling is a very important tool in the interpretation of the water-rock interaction processes. However, the space-time variation of the water composition is not taken into account, and it has no capacity to model advection, dispersion and kinetic processes.Se aborda la modelización de la interacción agua-roca mediante la Modelización Directa (MD y más específicamente la Modelización de Caminos de Reacción (MCR. Esta modelización analiza cuantitativamente la evolución del sistema hacia el equilibrio total

  8. Condición de transversalidad en el problema del líder con nuevo tiempo final libre y función final para la solución de equilibrio jerárquico en la interacción dinámica empresa-gobierno

    Directory of Open Access Journals (Sweden)

    Boj, E.

    1999-01-01

    Full Text Available Este trabajo trata de la interacción dinámica entre las empresas y el gobierno. Se presenta un modelo en el cual ambos agentes económicos maximizan sus ganancias totales corrientes actualizadas más el valor inicial de la ganancia final. El concepto de solución utilizado es de equilibrio jerárquico donde el gobierno asume el papel del líder. El método de resolución empleado consiste en enfocar el problema del líder como un problema de control óptimo con nuevo tiempo final libre, dentro del horizonte temporal original [0,T] , y con una nueva función final. Ésta recogerá la ganancia total del gobierno desde el nuevo tiempo final a determinar hasta T. Se hace uso de la correspondiente condición de transversalidad asociada. Se analizan los resultados y su interpretación económica.

  9. Niveles de plomo en sangre en niños de 8 a 10 años y su relación con la alteración en el sistema visomotor y del equilibrio Relationship of blood lead levels with visual-motor and equilibrium disturbances in children aged 8 to 10 years

    Directory of Open Access Journals (Sweden)

    María Isabel Azcona-Cruz

    2000-08-01

    Full Text Available OBJETIVO: Identificar si existe una asociación negativa entre los niveles de plomo en sangre y la coordinación visomotora y el equilibrio de escolares. MATERIAL Y MÉTODOS: Se realizó un estudio transversal en 255 niños de 8 a 10 años de edad, que asistían a escuelas del Sector 1 del Instituto de Educación Pública del Estado de Oaxaca, durante noviembre y diciembre de 1998. Se les aplicaron las pruebas de evaluación de la percepción visual de Frostig y la subescala de equilibrio Frostig Movement Skills Test Battery y se les tomó una muestra de sangre para la determinación de plomo por medio de espectrometría de absorción atómica. Asimismo, se aplicó un cuestionario sociodemográfico y se evaluó la historia de salud del niño. Se relacionó el nivel de plomo sanguíneo con los resultados de las pruebas de percepción visual y del equilibrio mediante modelos de regresión múltiple. Se usó la técnica de simulaciones de Montecarlo para probar el efecto del plomo dentro del modelo. RESULTADOS: La media geométrica de las concentraciones de plomo en sangre fue de 11.5 µg/dl (DE geométrica= +6.3, -5.2. El nivel de plomo se relacionó significativamente con el cociente de integración visomotora (p>0.042. Este disminuye 1.78 (IC 95% -3.51, -0.06 puntos por cada incremento de 10 µg/dl en los niveles de plomo en sangre del niño. De las pruebas que constituyeron este cociente, sólo se relacionó significativamente el plomo con la de coordinación ojo-mano (p=0.045 y de relaciones espaciales (p=0.039. El ingreso familiar también se relacionó significativamente con el cociente de integración visomotora, a mayor ingreso los resultados en las pruebas del niño fueron más altos. Sólo 3.1% de los niños obtuvieron puntuaciones consideradas clínicamente anormales. No se encontró una relación significativa entre el plomo y el cociente de la respuesta motriz reducida, el cociente de percepción visual general y las pruebas de

  10. Field transformations to multivalued fields

    Energy Technology Data Exchange (ETDEWEB)

    Kleinert, H [Institut fuer Theoretische Physik, Arnimallee 14, D-14195 Berlin (Germany)

    2007-05-15

    Changes of field variables may lead to multivalued fields which do not satisfy the Schwarz integrability conditions. Their quantum field theory needs special care as is shown in an application to the superfluid and superconducting phase transitions.

  11. Visual field

    Science.gov (United States)

    ... your visual field. How the Test is Performed Confrontation visual field exam. This is a quick and ... to achieve this important distinction for online health information and services. Learn more about A.D.A. ...

  12. PAPEL DE LA SEDE UNIVERSITARIA MUNICIPAL EN LA IMPLEMENTACIÓN DEL PROGRAMA DE PROMOCIÓN AGROECOLÓGICA EN LAS COOPERATIVAS CAMPESINAS, PARA EL APROVECHAMIENTO RACIONAL DE LOS RECURSOS NATURALES, LA SEGURIDAD ALIMENTARIA, RESTAURACIÓN DEL EQUILIBRIO ECOLÓGI

    Directory of Open Access Journals (Sweden)

    KENIA FAYE GONZÁLEZ

    2009-12-01

    Full Text Available El objetivo de este trabajo es evaluar el papel de la Sede Universitaria Municipal en la implementación del Programa de Promoción Agrícola "Campesino a Campesino", en las Cooperativas Campesinas de Camajuaní. El uso de las tecnologías agroecológicas en las Cooperativas campesinas de Camajuaní marca el inicio del desarrollo sustentable, desde el punto de vista económico y ecológico. Las fincas muestran un uso más intensivo del recurso tierra expresado en el número de especies manejadas, así como en el contenido de materia orgánica. El campesino mejora los resultados de la producción, sus condiciones económicas sociales y gana en calidad de vida. Los patrones dominantes de producción y consumo contribuían al deterioro ambiental, y se debe detener ese deterioro, de manera que se recupere la diversidad biológica y la calidad de los ecosistemas, creando las condiciones para un equilibrio entre el desarrollo comunitario y la protección de la biosfera. La agricultura sustentable se convierte en un paradigma que sirve como vía para garantizar una alimentación sana y estable sin afectar al medio. Pretende compatibilizar la conservación de los recursos naturales y laprotección del ambiente, con la producción de cantidades suficiente de alimentos para garantizar el bienestar de las generaciones presentes y futuras.

  13. The phase equilibrium diagrams as a tool for the design and use of refractories; Los diagramas de equilibrio de fases como una herramienta para el diseno y comprension del comportamiento en servicio de los materiales refractarios

    Energy Technology Data Exchange (ETDEWEB)

    Aza, A. H. de; Pena, P.; Caballero, A.; Aza, S. de

    2011-07-01

    Refractories are complex materials used at high temperature, in severely corrosive atmospheres and in contact with aggressive liquids. The high temperatures imply that such systems tend to equilibrium and this is frequently attained during service; at least local equilibrium is achieved. This allows the basic principles of phase diagrams to be used in this technology. Traditionally, refractories have been designed to be close to equilibrium so that in-service changes were restricted. Currently, additions of raw materials are often made that will react in use, in a controlled manner, to give favorable effects under the service conditions. Equilibrium diagrams are valid not only for determining the thermodynamic tendency but also for predicting the final equilibrium state and to know the way through which the material moves into the final state. In this context equilibrium diagrams become a powerful tool for a better understanding of the behavior of refractories during service. After a general consideration on the importance of phase equilibrium diagrams in this field, criteria for using equilibrium diagrams, as a tool for improving traditional refractories and/or designing advanced or new refractories, will be given. Pertinent examples in different systems will be discussed. This paper compiles and reviews the last plenary lecture given by Professor Salvador De Aza on the subject. (Author) 58 refs.

  14. Magnetic Field

    DEFF Research Database (Denmark)

    Olsen, Nils

    2015-01-01

    he Earth has a large and complicated magnetic field, the major part of which is produced by a self-sustaining dynamo operating in the fluid outer core. Magnetic field observations provide one of the few tools for remote sensing the Earth’s deep interior, especially regarding the dynamics...... of the fluid flow at the top of the core. However, what is measured at or near the surface of the Earth is the superposition of the core field and fields caused by magnetized rocks in the Earth’s crust, by electric currents flowing in the ionosphere, magnetosphere, and oceans, and by currents induced...... in the Earth by time-varying external fields. These sources have their specific characteristics in terms of spatial and temporal variations, and their proper separation, based on magnetic measurements, is a major challenge. Such a separation is a prerequisite for remote sensing by means of magnetic field...

  15. Phase field

    International Nuclear Information System (INIS)

    Radhakrishnan, B.; Gorti, S.B.; Clarno, K.; Tonks, M.R.

    2015-01-01

    In this work, the phase-field method and its application to microstructure evolution in reactor fuel and clad are discussed. The examples highlight the capability of the phase-field method to capture evolution processes that are influenced by both thermal and elastic stress fields that are caused by microstructural changes in the solid-state. The challenges that need to be overcome before the technique can become predictive and material-specific are discussed. (authors)

  16. Field Report

    DEFF Research Database (Denmark)

    Gorm Hansen, Louise Lyngfeldt

    2012-01-01

    This field report expresses perfectly the kind of confusion almost all of us experience when entering the field. How do we know whether what we’re doing is “right” or not? What in particular should we record when we don’t have time to write down everything among all the myriad impressions thrusting...

  17. Proposta de atuação fisioterapêutica em uma criança com síndrome de Angelman, enfatizando o equilíbrio postural: estudo de caso Propuesta de actuación fisioterapéutica en un niño con Síndrome de Angelman, enfatizando el equilibrio postural: estudio de caso Proposal for a physical therapy program in a child with Angelman syndrome, emphasizing postural balance: a case study

    Directory of Open Access Journals (Sweden)

    Livia Pessarelli Visicato

    2013-03-01

    Full Text Available A síndrome de Angelman (SA é caracterizada por alterações neuromotoras como marcha atáxica e atraso na aquisição de habilidades motoras, porém são escassos os estudos investigando o efeito de intervenções aplicadas a essa população. O objetivo do estudo foi verificar o efeito de um treino de equilíbrio em uma criança com SA. Participou do estudo uma criança de nove anos de idade com diagnóstico de SA, sexo feminino. Foi aplicado um protocolo para treino de equilíbrio por oito semanas, com frequência de duas vezes por semana. O treino consistiu em atividades envolvendo equilíbrio estático sob diversas condições de dificuldade. Após o treino, a análise de biofotogrametria computadorizada do equilíbrio estático revelou redução do grau de oscilação, que passou de 38° para 13,78°. A pontuação na escala de Berg passou de 27 pontos, na avaliação, para 37 pontos na reavaliação. No teste Timed Up & Go, a criança realizou a tarefa em 15 segundos, na avaliação, e, na reavaliação, em 12 segundos. Em conjunto, os resultados sugerem que o treino favoreceu melhora no equilíbrio estático e dinâmico, bem como na mobilidade funcional.El síndrome de Angelman (SA es caracterizado por alteraciones neuromotoras como marcha atáxica y atraso en la adquisición de habilidades motoras, pero son escasos los estudios investigando el efecto de intervenciones aplicadas a esta población. El objetivo de este estudio fue verificar el efecto de un entrenamiento del equilibrio en un niño con SA. Participó del estudio un niño de 9 años de edad con diagnóstico de SA, sexo femenino. Fue aplicado un protocolo de entrenamiento para el equilibrio por 8 semanas, con frecuencia de 2 veces por semana. El entrenamiento consistió en actividades involucrando el equilibrio estático sobre diversas condiciones de dificultad. Después del entrenamiento el análisis de biofotogrametría computarizada del equilibrio estático reveló reducci

  18. Validation of a Short Form of the Greek Version of the Decisional Balance Scale in the Exercise Domain. (Validación de la Versión Griega de la Escala Abreviada de Equilibrio Decisional en el Campo del Ejercicio Físico.

    Directory of Open Access Journals (Sweden)

    Konstantinos Karteroliotis

    2008-04-01

    Full Text Available AbstractAlthough the Decisional Balance Scale (DBS for exercise has been established to have sound psychometric properties, the factorial structure of this instrument has not been examined in other European countries. The purpose of this study was to test a short version of the decisional balance scale for exercise in Greek adults. The DBS was administered to 158 (61.2% women and 100 (38.8% men. An exploratory factor analysis yielded a positive (pros factor and a negative (cons factor. The results from confirmatory factor analysis indicated that the two-factor structure was the best fit for the DBS when it was used with Greek adults. The alpha coefficients were .84 for the positive factor and .81 for the negative factor. The findings are similar to those of the English original, and suggest that the revised DBS can be used in exercise and activity research with Greek adults. However, to expand the usefulness of this instrument across cultures, the DBS should continue to be tested with other Greek populations and settings.Resumen La escala del equilibrio decisional (DBS presenta unas sólidas propiedades psicométricas, no obstante la estructura factorial de dicho instrumento no se ha examinado en otros países europeos. Este estudio tiene como objetivo probar una versión corta de la escala decisional sobre ejercicio a una muestra de adultos griegos. La DBS revisada se administró a 158 (61.2% participantes mujeres y 100 (38.8% hombres. El análisis factorial exploratorio mostró la presencia de dos factores, uno positivo (los pros y uno negativo (los contras. Los resultados del análisis factorial confirmatorio indicaron que la mejor solución factorial para la versión griega de la escala DBS se componía de una doble estructura. Los coeficientes alpha fueron de .84 para el factor positivo y de .81 para el factor negativo. Los hallazgos de este estudio fueron similares a los de la versión original, indicando que la revisada DBS es adecuada

  19. Field Notes

    Data.gov (United States)

    US Agency for International Development — This is a mobile application for capturing images , data, and geolocation for USAID projects in the field. The data is then stored on a server in AllNet. The...

  20. Selfdecomposable Fields

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole E.; Sauri, Orimar; Szozda, Benedykt

    In the present paper we study selfdecomposability of random fields, as defined directly rather than in terms of finite-dimensional distributions. The main tools in our analysis are the master Lévy measure and the associated Lévy-Itô representation. We give the dilation criterion for selfdecomposa......In the present paper we study selfdecomposability of random fields, as defined directly rather than in terms of finite-dimensional distributions. The main tools in our analysis are the master Lévy measure and the associated Lévy-Itô representation. We give the dilation criterion...... for selfdecomposability analogous to the classical one. Next, we give necessary and sufficient conditions (in terms of the kernel functions) for a Volterra field driven by a Lévy basis to be selfdecomposable. In this context we also study the so-called Urbanik classes of random fields. We follow this with the study...... of existence and selfdecomposability of integrated Volterra fields. Finally, we introduce infinitely divisible field-valued Lévy processes, give the Lévy-Itô representation associated with them and study stochastic integration with respect to such processes. We provide examples in the form of Lévy...

  1. Selfdecomposable Fields

    DEFF Research Database (Denmark)

    Barndorff-Nielsen, Ole E.; Sauri, Orimar; Szozda, Benedykt

    In the present paper we study selfdecomposability of random fields, as defined directly rather than in terms of finite-dimensional distributions. The main tools in our analysis are the master L\\'evy measure and the associated L\\'evy-It\\^o representation. We give the dilation criterion for selfdec......In the present paper we study selfdecomposability of random fields, as defined directly rather than in terms of finite-dimensional distributions. The main tools in our analysis are the master L\\'evy measure and the associated L\\'evy-It\\^o representation. We give the dilation criterion...... for selfdecomposability analogous to the classical one. Next, we give necessary and sufficient conditions (in terms of the kernel functions) for a Volterra field driven by a L\\'evy basis to be selfdecomposable. In this context we also study the so-called Urbanik classes of random fields. We follow this with the study...... of existence and selfdecomposability of integrated Volterra fields. Finally, we introduce infinitely divisible field-valued L\\'evy processes, give the L\\'evy-It\\^o representation associated with them and study stochastic integration with respect to such processes. We provide examples in the form of L...

  2. Random Fields

    Science.gov (United States)

    Vanmarcke, Erik

    1983-03-01

    Random variation over space and time is one of the few attributes that might safely be predicted as characterizing almost any given complex system. Random fields or "distributed disorder systems" confront astronomers, physicists, geologists, meteorologists, biologists, and other natural scientists. They appear in the artifacts developed by electrical, mechanical, civil, and other engineers. They even underlie the processes of social and economic change. The purpose of this book is to bring together existing and new methodologies of random field theory and indicate how they can be applied to these diverse areas where a "deterministic treatment is inefficient and conventional statistics insufficient." Many new results and methods are included. After outlining the extent and characteristics of the random field approach, the book reviews the classical theory of multidimensional random processes and introduces basic probability concepts and methods in the random field context. It next gives a concise amount of the second-order analysis of homogeneous random fields, in both the space-time domain and the wave number-frequency domain. This is followed by a chapter on spectral moments and related measures of disorder and on level excursions and extremes of Gaussian and related random fields. After developing a new framework of analysis based on local averages of one-, two-, and n-dimensional processes, the book concludes with a chapter discussing ramifications in the important areas of estimation, prediction, and control. The mathematical prerequisite has been held to basic college-level calculus.

  3. ALGORITMO ETAPA A ETAPA PARA LA SIMULACIÓN DE CASCADAS DE EXTRACCIÓN EN FASE LÍQUIDA APLICANDO EL MODELO DE EQUILIBRIO ALGORITMO ETAPA A ETAPA PARA A SIMULAÇÃO DE CASCATAS DE EXTRAÇÃO EM FASE LÍQUIDA APLICANDO O MODELO DE EQUILÍBRIO STAGE-BY-STAGE ALGORITHM FOR SIMULATION OF LIQUID PHASE EXTRACTION CASCADES APPLYING THE EQUILIBRIUM MODEL

    Directory of Open Access Journals (Sweden)

    César A Sánchez

    2009-12-01

    Full Text Available Se presenta un método de solución etapa a etapa para el conjunto de ecuaciones de balance de masa, relaciones de equilibrio, suma de composiciones y entalpía (MESH, mass equilibrium sum enthalpy que representan el modelo de equilibrio para un arreglo a contracorriente de etapas de extracción en fase líquida. El fundamento teórico se encuentra en la termodinámica: equilibrio líquido-líquido, flash isotérmico y flash adiabático. El algoritmo supera los alcances de los métodos gráficos e isotérmicos típicos en el estudio de los procesos de extracción y es aplicable a situaciones adicionales muy comunes: transferencia de calor en las etapas, etapas adiabáticas, temperaturas diferentes para los flujos de alimentación y solvente. El algoritmo se ilustra en tres ejemplos, los dos primeros en operación isotérmica con tres componentes (agua, ácido acético y acetato de butilo y diez etapas, y un tercero más elaborado que involucra transferencia de calor con cuatro componentes (agua, ácido acético, butanol y acetato de butilo y quince etapas.Apresenta-se um método de solução etapa a etapa para o conjunto de equações de balanço de massa, relações de equilíbrio, soma de composições e entalpia (MESH mass equilibrium sum enthalpy que representam o modelo de equilíbrio para um arranjo en contracorrente de períodos de extração em fase líquida. O fundamento teórico se encontra na termodinâmica: equilíbrio líquido-líquido, flash isotérmico e flash adiabático. O algoritmo supera os alcances dos métodos gráficos e isotérmicos típicos no estudo dos processos de extração e é aplicável a situações adicionais muito comuns: transferência de calor nas etapas, etapas adiabáticas, temperaturas diferentes para os fluxos de alimentação e solvente. O algoritmo se ilustra em três exemplos, os dois primeiros em operação isotérmica com três componentes (água, ácido acético e acetato de butila e dez etapas, e um

  4. Field theories with subcanonical fields

    International Nuclear Information System (INIS)

    Bigi, I.I.Y.

    1976-01-01

    The properties of quantum field theories with spinor fields of dimension less than the canonical value of 3/2 are studied. As a starting point for the application of common perturbation theory we look for the linear version of these theories. A gange-interaction is introduced and with the aid of power counting the renormalizability of the theory is shown. It follows that in the case of a spinor-field with negative dimension renormalization can only be attained if the interaction has a further symmetry. By this symmetry the theory is determined in an unequivocal way. The gange-interaction introduced in the theory leads to a spontaneous breakdown of scale invariance whereby masses are produced. At the same time the spinor-field operators can now be separated in two orthogonal sections with opposite norm. It is proposed to use the section with negative (positive) norm to describe hadrons (leptons) respectively. (orig./WL) [de

  5. Gas-flow detector for uranium contamination on finned-can surface of a reactor fuel; Detecteur a courant gazeux pour deceler la contamination en uranium des nervures des gaines de combustible nucleaire; Gazopotochnyj detektor zagryazneniya uranom rebristoj poverkhnosti obolochki reaktornykh teplovydelyayushchikh ehlementov; Detector de flujo gaseoso para medir la contaminacion de uranio en la superficie de la vaina de aletas de los elementos combustibles para reactores

    Energy Technology Data Exchange (ETDEWEB)

    Miwa, H; Shiojiri, T; Maeda, Y [Kobe Kogyo Corporation, Okubo, Akashi, Hyogo (Japan)

    1962-04-15

    This gas-flow detector is a gridded proportional-counter specially designed for detecting uranium contamination on the finned-can surface of a reactor fuel. A conventional proportional-counter constructed only by a cathode and collector can hardly detect alpha particles emitted from uranium which is contaminated on rugged surfaces such as those of the fins of a reactor-fuel can because of the lack of uniformity of the electric field near the surface. This is the reason why we have constructed the gridded proportional-counter. This counter comprises the fuel, a grid, collectors and a cathode which are cylindrical in construction and arranged coaxially. The fuel is placed in the centre of the grid and negative voltage is applied. The space between the fuel and the grid serves as an ion-collecting space. The grid is made of fine parallel tungsten wires which are constructed cylindrically around the fuel and connected to ground potential. The collectors are 16 fine tungsten wires constructed similarly to the grid, but each wire is electrically insulated from the others. Through 50-k{Omega} resistors all collectors are connected together and to positive high voltage via a feeding resistor. The space between the grid, the collectors and the cathode serves as a gas-multiplication space just like a conventional proportional-counter. Each 50-k{Omega} resistor separates the stray capacity of the connected collector from the others. The detector output is coupled with a low input-impedance-current amplifier. The low inputimpedance also lessens the bad influence of the stray capacity of the input circuitry. These result in a good S/N ratio and allow the sensitive detection of alpha particles. Before measurement, the counter is first evacuated by a rotary pump and then PR gas (A: 90%, Methane: 10%) is admitted. By the use of this new equipment we have successfully detected alpha particles emitted from 1 x 10{sup -5} g natural-uranium contamination of the finned-can surface of a

  6. Dialética da autonomia dos equilíbrios nos conflitos entre pacientes e cirurgiões oncológicos Dialéctica de la autonomía de los equilibrios en los conflictos entre pacientes y cirujanos oncológicos Dialetics of balanced autonomy in disagreements between patients and oncological surgeons

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Vasconcellos-Silva

    2009-10-01

    oncológicos especializados en tumores de cabeza y cuello de la ciudad de Rio de Janeiro, Sureste de Brasil, entre 2000 y 2005. Los participantes fueron seleccionados por "chain sampling" y la interrupción del trabajo de campo obedeció al criterio de saturación. Utilizándose la técnica de análisis de discurso, se buscó identificar las premisas estructurantes del concepto de autonomía, que compondrían una dialéctica discursiva en el contexto de los pacientes que se niegan a someterse a cirugías consideradas mutiladoras. ANÁLISIS DE LOS RESULTADOS: Inicialmente, los cirujanos exhibieron asertivas estandarizadas, centradas en conceptos deontológicos de autonomía. En la medida que narraban sus experiencias, fueron observados auto-cuestionamientos que exponían contradicciones con relación al concepto cotidiano de "resecabilidad informada". En este punto los discursos estandarizados se dejan colar por auto-cuestionamientos sobre la necesidad de un retorno al equilibrio existencial perjudicado por el cáncer. CONCLUSIONES: Las narrativas expresaron demandas por una "autonomía de equilibrios" en la forma de un semi-projecto no idealizable apriorísticamente, a pesar de que sea dependiente de interacciones con el otro. Los resultados indican la necesidad de reflexión ante el concepto de autonomía como premisa lineal, categórica e individual que, a pesar de ser superficialmente elaborada, ha gobernado las acciones cotidianas.OBJECTIVE: To comprehend different logics of autonomy that are present in conflicts between surgical prescriptions and the expectations of patients with diagnoses of cancer. METHODOLOGICAL PROCEDURES: This is a qualitative study in which 11 semistructured interviews were conducted with oncological surgeons specializing in head and neck tumors, in the city of Rio de Janeiro, Southeastern Brazil, between 2000 and 2005. The participants were selected by means of chain sampling and the fieldwork was halted in accordance with the criterion of

  7. Gauge fields

    International Nuclear Information System (INIS)

    Itzykson, C.

    1978-01-01

    In these notes the author provides some background on the theory of gauge fields, a subject of increasing popularity among particle physicists (and others). Detailed motivations and applications which are covered in the other lectures of this school are not presented. In particular the application to weak interactions is omitted by referring to the introduction given by J. Ilipoulos a year ago (CERN Report 76-11). The aim is rather to stress those aspects which suggest that gauge fields may play some role in a future theory of strong interactions. (Auth.)

  8. El escritor y el diagrama del punto de equilibrio

    OpenAIRE

    Pertierra, Omar A.

    1996-01-01

    El objetivo del presente trabajo es proveer una alternativa más, aunada a las ya existentes, para el autor de una determinada obra escrita (literaria, texto, etc.) en lo concerniente al aspecto económico (contrato de edición, específicamente). Departamento de Bibliotecología

  9. Equilibrio postural e musculoesquelético de skatistas

    Directory of Open Access Journals (Sweden)

    Davi Schilling

    2014-09-01

    Full Text Available Objetivo: Verificar a relação existente entre a prática do skate e os equilíbrios musculoesquelético e postural látero-lateral do corpo. Método: A amostra foi composta por 10 skatistas das categorias amador 1 e 2 residentes na grande Porto Alegre. Foram realizados quatro procedimentos de avaliação: (1 teste de força máxima isométrica, através de contração voluntária máxima isométrica, (2 teste de comprimento muscular, (3 medida das alturas dos ângulos inferiores das escápulas, espinha ilíaca póstero-superior, linha poplítea do joelho e (4 questionário sobre a técnica utilizada no esporte. Os dados foram submetidos à estatística inferencial e descritiva. Resultados e considerações finais: Verificou-se que não existem diferenças significativas (p>0,05 para força, comprimento muscular e alturas corporais entre os lados direito e esquerdo do corpo. Estes resultados sugerem a existência de equilíbrio musculoesquelético dos membros inferiores e cintura pélvica, bem como equilíbrio postural látero-lateral, independente da frequência de alternância do pé de embalo ou da base utilizada na prática do skate.

  10. La transformación y el equilibrio

    Directory of Open Access Journals (Sweden)

    Valdivieso Susana

    1986-12-01

    Full Text Available El propósito central de este artículo es la comparación de los trabajos de dos de los economistas que han participado recientemente en la polemica: Homero Cuevas y Anwar Shaikh, en un esfuerzo por enfatizar cuales son los elementos que deben estar presentes en cualquier intento de solución al llamado problema de la transformación.

  11. Equilibrios de precipitación. Cálculo de concentraciones en el equilibrio en disoluciones diluidas.

    OpenAIRE

    Milla González, Miguel

    2016-01-01

    En este ejercicio se mezclan volúmenes de cloruro de bario y sulfato de sodio a niveles bajos de concentración y debe encontrarse la fracción de sulfato de bario que ha precipitado. El ejercicio combina los balances de masa para llegar a una ecuación cuadrada que se resuelve. Una animación simula el proceso.

  12. Field theory

    CERN Multimedia

    1999-11-08

    In these lectures I will build up the concept of field theory using the language of Feynman diagrams. As a starting point, field theory in zero spacetime dimensions is used as a vehicle to develop all the necessary techniques: path integral, Feynman diagrams, Schwinger-Dyson equations, asymptotic series, effective action, renormalization etc. The theory is then extended to more dimensions, with emphasis on the combinatorial aspects of the diagrams rather than their particular mathematical structure. The concept of unitarity is used to, finally, arrive at the various Feynman rules in an actual, four-dimensional theory. The concept of gauge-invariance is developed, and the structure of a non-abelian gauge theory is discussed, again on the level of Feynman diagrams and Feynman rules.

  13. Incidência Pélvica: um parâmetro fundamental para definição do equilíbrio sagital da coluna vertebral Incidência pélvica: un parámetro fundamental para definir el equilibrio sagital de la columna Pelvic incidence: a fundamental parameter for defining the sagittal balance of the spine

    Directory of Open Access Journals (Sweden)

    Sérgio Afonso Henneman

    2012-09-01

    Full Text Available Este trabalho propõe um parâmetro anatômico, a incidência pélvica, como fator chave para a compreensão do alinhamento da coluna vertebral. Existe estreita relação, tanto para indivíduos normais como para indivíduos com deformidades da coluna, entre o parâmetro anatômico de incidência pélvica e a inclinação sacral, determinantes da lordose lombar. O ângulo de Cobb e a rotação vertebral apical servem de instrumento para o entendimento do aspecto tridimensional da coluna vertebral e das relações entre a pelve e a coluna. Uma equação preditiva para lordose é apresentada. A incidência pélvica parece ser o fator determinante do equilíbrio sagital da coluna. Ela determina as curvas da coluna vertebral, variando conforme outros parâmetros.En este trabajo se propone un parámetro anatómico, la incidencia de la pelvis, como el factor clave para entender la alineación de la columna vertebral. Hay estrecha relación, tanto para el normal y para las personas con deformidades de la columna entre el parámetro anatómico de la incidencia de la pelvis y la inclinación del sacro, determinantes de la lordosis lumbar. El ángulo de Cobb y la rotación vertebral apical sirven como una herramienta para entender el aspecto tridimensional de la columna vertebral y de su relación con la pelvis. Se presenta una ecuación de predicción para la lordosis. La incidencia pélvica parece ser el factor determinante del equilibrio sagital de la columna. Dicha ecuación determina las curvas de la columna y varía según otros parámetros.This paper proposes an anatomical parameter, the pelvic incidence, as the key factor for managing the spinal balance. There is a close relationship for both normal individuals and those with spinal deformities between the anatomical parameter of pelvic incidence and the sacral slope, which determine lumbar lordosis. The Cobb angle and the apical vertebral rotation serve as a tool for understanding the three

  14. Gauge fields

    International Nuclear Information System (INIS)

    Mills, R.

    1989-01-01

    This article is a survey of the history and ideas of gauge theory. Described here are the gradual emergence of symmetry as a driving force in the shaping of physical theory; the elevation of Noether's theorem, relating symmetries to conservation laws, to a fundamental principle of nature; and the force of the idea (''the gauge principle'') that the symmetries of nature, like the interactions themselves, should be local in character. The fundamental role of gauge fields in mediating the interactions of physics springs from Noether's theorem and the gauge principle in a remarkably clean and elegant way, leaving, however, some tantalizing loose ends that might prove to be the clue to a future deeper level of understanding. The example of the electromagnetic field as the prototype gauge theory is discussed in some detail and serves as the basis for examining the similarities and differences that emerge in generalizing to non-Abelian gauge theories. The article concludes with a brief examination of the dream of total unification: all the forces of nature in a single unified gauge theory, with the differences among the forces due to the specific way in which the fundamental symmetries are broken in the local environment

  15. Field training

    International Nuclear Information System (INIS)

    Mumford, G.E.; Hadaway, E.H.

    1991-01-01

    Individualized, personal training can be used to increase an employee's awareness of the HSE program. Such training can stimulate personal commitment and provide personal skills that can be utilized for the benefit of the overall HSE effort. But, providing such training within our industry can be a difficult task due to the scheduling, travel arrangements, and cost associated with bringing employees from isolated, remote locations to centrally located training facilities. One method of overcoming these obstacles involves the use of field instructors to provide the training at the many, and varied number of individuals can be reached with minimal disruption to their work scheduling or to their time off. In fact, this type of on-site training is already used by some oil companies and drilling contractors with encouraging results. This paper describes one drilling contractor's experiences with such a training program. The results after eight years how that this program not only can provide and efficient, economical means of employee training, but also can have a direct application to employee motivation regarding a company's HSE effort

  16. An electric field in a gravitational field

    International Nuclear Information System (INIS)

    Harpaz, Amos

    2005-01-01

    The behaviour of an electric field in a gravitational field is analysed. It is found that due to the mass (energy) of the electric field, it is subjected to gravity and it falls in the gravitational field. This fall curves the electric field, a stress force (a reaction force) is created, and the interaction of this reaction force with the static charge gives rise to the creation of radiation

  17. Chemical changes in well fluids from the Los Humeros geothermal field: Evidences for deep recharge; Cambios quimicos en fluidos de pozos del campo geotermico de Los Humeros: Evidencia de recarga profunda

    Energy Technology Data Exchange (ETDEWEB)

    Barragan Reyes, Rosa Maria; Arellano Gomez, Victor Manuel [Instituto de Investigaciones Electricas, Gerencia de Geotermia, Cuernavaca, Morelos (Mexico)]. E-mail: rmb@iie.org.mx; Flores Armenta, Magaly [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico); Tovar Aguado, Rigoberto [Comision Federal de Electricidad (Mexico)

    2008-07-15

    Fluid (water and steam) chemical changes over time were studied in 20 wells in the Los Humeros, Mexico, geothermal field for the purpose of correlating such changes with physical processes occurring in the reservoir due to exploitation. Most wells (except well H-1) produce high-enthalpy fluids with almost no liquid, making gas geochemistry important in this field. Liquid-phase studies include fluid classification, determination of water-rock equilibrium state, and reservoir-temperature estimates. Changes in gas composition through time were studied using the Fischer-Tropsch (FT) reaction and the combined balance pyrite-hematite-magnetite (HSH2) as the buffer controlling H{sub 2}S fluid concentration. Data for most wells from 1987-1995 and 2000-2005 indicate the presence of deeper-fluid recharge, with maximum temperatures occurring in 1994-95 and 2005. The estimated temperature in well H-1 in 1994 was 305 degrees Celsius and the estimated temperature in well H-7 was 338 degrees Celsius in 1995. Temperature estimations from 2005 data were 222 degrees Celsius in well H-1D and 350 degrees Celsius in well H-7. These results are considered caused by the entrance of deeper fluids due to the increase of secondary permeability, which in turn is related to the seismicity increase in the zone. At the same time, re-injection returns in the steam phase were identified in well discharges during 1995-2000 by means of the FT-HSH2 diagram. [Spanish] Se realizo un estudio de los cambios quimicos ocurridos en fluidos (liquido y vapor) de veinte pozos del campo geotermico de Los Humeros, Pue., Mexico, con objeto de investigar la ocurrencia de procesos del yacimiento relacionados con la explotacion. La mayoria de los pozos (excepto el pozo H-1) se caracterizan por producir descargas de alta entalpia con escasa produccion de liquido, por lo que en este campo la geoquimica de gases juega un papel importante. El estudio de la fase liquida incluyo la clasificacion de los fluidos, la

  18. Quantized fields in external field. Pt. 2

    International Nuclear Information System (INIS)

    Bellissard, J.

    1976-01-01

    The case of a charged scalar field is considered first. The existence of the corresponding Green's functions is proved. For weak fields, as well as pure electric or scalar external fields, the Bogoliubov S-operator is shown to be unitary, covariant, causal up-to-a-phase. These results are generalised to a class of higher spin quantized fields, 'nicely' coupled to external fields, which includes the Dirac theory, and in the case of minimal and magnetic dipole coupling, the spin one Petiau-Duffin-Kemmer theory. (orig.) [de

  19. Gravitation and vacuum field

    International Nuclear Information System (INIS)

    Tevikyan, R.V.

    1986-01-01

    This paper presents equations that describe particles with spins s = 0, 1/2, 1 completely and which also describe 2s + 2 limiting fields as E → ∞. It is shown that the ordinary Hilbert-Einstein action for the gravitation field must be augmented by the action for the Bose vacuum field. This means that one must introduce in the gravitational equations a cosmological term proportional to the square of the strength of the Bose vacuum field. It is shown that the theory of gravitation describes three realities: matter, field, and vacuum field. A new form of matter--the vacuum field--is introduced into field theory

  20. Fractal vector optical fields.

    Science.gov (United States)

    Pan, Yue; Gao, Xu-Zhen; Cai, Meng-Qiang; Zhang, Guan-Lin; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2016-07-15

    We introduce the concept of a fractal, which provides an alternative approach for flexibly engineering the optical fields and their focal fields. We propose, design, and create a new family of optical fields-fractal vector optical fields, which build a bridge between the fractal and vector optical fields. The fractal vector optical fields have polarization states exhibiting fractal geometry, and may also involve the phase and/or amplitude simultaneously. The results reveal that the focal fields exhibit self-similarity, and the hierarchy of the fractal has the "weeding" role. The fractal can be used to engineer the focal field.

  1. Electric Field Imaging

    Data.gov (United States)

    National Aeronautics and Space Administration — NDE historically has focused technology development in propagating wave phenomena with little attention to the field of electrostatics and emanating electric fields....

  2. How fields vary.

    Science.gov (United States)

    Krause, Monika

    2018-03-01

    Field theorists have long insisted that research needs to pay attention to the particular properties of each field studied. But while much field-theoretical research is comparative, either explicitly or implicitly, scholars have only begun to develop the language for describing the dimensions along which fields can be similar to and different from each other. In this context, this paper articulates an agenda for the analysis of variable properties of fields. It discusses variation in the degree but also in the kind of field autonomy. It discusses different dimensions of variation in field structure: fields can be more or less contested, and more or less hierarchical. The structure of symbolic oppositions in a field may take different forms. Lastly, it analyses the dimensions of variation highlighted by research on fields on the sub- and transnational scale. Post-national analysis allows us to ask how fields relate to fields of the same kind on different scales, and how fields relate to fields on the same scale in other national contexts. It allows us to ask about the role resources from other scales play in structuring symbolic oppositions within fields. A more fine-tuned vocabulary for field variation can help us better describe particular fields and it is a precondition for generating hypotheses about the conditions under which we can expect to observe fields with specified characteristics. © London School of Economics and Political Science 2017.

  3. Magnetic Field Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...

  4. Magnetic field reconnexion in a sheared field

    International Nuclear Information System (INIS)

    Ugai, M.

    1981-01-01

    A nonlinear development of the Petschek mode in a sheared magnetic field where there is a field component Bsub(z) along an X line is numerically studied. It is found that finite-amplitude intermediate waves, adjacent to the slow shock, may eventually stand in the quasi-steady configuration; on the other hand, the fundamental characteristics of the Petschek-mode development are scarcely influenced, either qualitatively or quantitatively, by the Bsub(z) field. (author)

  5. Wake fields and wake field acceleration

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Wilson, P.B.; Weiland, T.

    1984-12-01

    In this lecture we introduce the concepts of wake fields and wake potentials, examine some basic properties of these functions, show how they can be calculated, and look briefly at a few important applications. One such application is wake field acceleration. The wake field accelerator is capable of producing the high gradients required for future very high energy e + e - linear colliders. The principles of wake field acceleration, and a brief description of experiments in progress in this area, are presented in the concluding section. 40 references, 27 figures

  6. On Jacobi-fields

    International Nuclear Information System (INIS)

    Bruening, E.

    1981-01-01

    The concept of a Jacobi-field is introduced as such a field for which the field-operators have the form of a generalized Jacobi-matrix with respect to the n-field-sector decomposition of the state-space. It is argued that the class of Jacobi-fields is of interest for relativistic quantum field theory for two reasons: (a) Jacobi-fields allow a direct association of particles (charges etc.) with fields. The concept of (generalized) creation- and annihilation-operators is thus available. (b) Jacobi-fields belong to that class of fields which can be characterized in terms of finitely many vacuum expectation values. A characterization of Jacobi-fields in terms of continuity and hermiticity properties of their system of vacuum expectation values is derived. Furthermore it is argued that all examples of relativistic quantum fields in a four-dimensional space-time are Jacobi-fields. This is evident for generalized free fields and Wick-powers of free fields, but is also true for a class of generalized Wick-powers of generalized free fields. (Auth.)

  7. Field Trips. Beginnings Workshop.

    Science.gov (United States)

    Cartwright, Sally; Aronson, Susan S.; Stacey, Susan; Winbush, Olga

    2001-01-01

    Five articles highlight benefits and organization of field trips: (1) "Field Trips Promote Child Learning at Its Best"; (2) "Planning for Maximum Benefit, Minimum Risk"; (3) "Coaching Community Hosts"; (4) "The Story of a Field Trip: Trash and Its Place within Children's Learning and Community"; and (5) "Field Trip Stories and Perspectives" (from…

  8. Field Campaign Guidelines

    Energy Technology Data Exchange (ETDEWEB)

    Voyles, J. W. [DOE ARM Climate Research Facility, Washington, DC (United States); Chapman, L. A. [DOE ARM Climate Research Facility, Washington, DC (United States)

    2015-12-01

    This document establishes a common set of guidelines for the Atmospheric Radiation Measurement (ARM) Climate Research Facility for planning, executing, and closing out field campaigns. The steps that guide individual field campaigns are described in the Field Campaign Tracking System and are specifically tailored to meet the scope of each field campaign.

  9. The Galactic magnetic fields

    International Nuclear Information System (INIS)

    Han Jinlin

    2006-01-01

    A good progress has been made on studies of Galactic magnetic fields in last 10 years. I describe what we want to know about the Galactic magnetic fields, and then review we current knowledge about magnetic fields in the Galactic disk, the Galactic halo and the field strengths. I also listed many unsolved problems on this area

  10. Gauge fields in a torsion field

    International Nuclear Information System (INIS)

    Rosu, Ion

    2004-01-01

    In this paper we analyse the motion and the field equations in a non-null curvature and torsion space. In this 4-n dimensional space, the connection coefficients are γ bc a = 1/2S bc a + 1/2T bc a, where S bc a is the symmetrical part and T bc a are the components of the torsion tensor. We will consider that all the fields depend on x = x α , α = 1,2,3,4 and do not depend on y = y k , k=1,2,...,n. The factor S bc a depends on the components of the metric tensor g αβ (x) and on the gauge fields A ν s 0 (x) and the components of the torsion depend only on the gauge fields A ν s 0 (x). We take into consideration the particular case for which the geodesic equations coincide with the motion equations in the presence of the gravitational and the gauge fields. In this case the field equations are Einstein equations in a 4-n dimensional space. We show that both the geodesic equations and the field equations can be obtained from a variational principle. (author)

  11. Engineering field theory

    CERN Document Server

    Baden Fuller, A J

    2014-01-01

    Engineering Field Theory focuses on the applications of field theory in gravitation, electrostatics, magnetism, electric current flow, conductive heat transfer, fluid flow, and seepage.The manuscript first ponders on electric flux, electrical materials, and flux function. Discussions focus on field intensity at the surface of a conductor, force on a charged surface, atomic properties, doublet and uniform field, flux tube and flux line, line charge and line sink, field of a surface charge, field intensity, flux density, permittivity, and Coulomb's law. The text then takes a look at gravitation

  12. Ambient Field Analysis at Groningen Gas Field

    Science.gov (United States)

    Spica, Z.; Nakata, N.; Beroza, G. C.

    2016-12-01

    We analyze continuous ambient-field data at Groningen gas field (Netherlands) through cross-correlation processing. The Groningen array is composed of 75 shallow boreholes with 6 km spacing, which contain a 3C surface accelerometer and four 5-Hz 3C borehole geophones spaced at 50 m depth intervals. We successfully retrieve coherent waves from ambient seismic field on the 9 components between stations. Results show high SNR signal in the frequency range of 0.125-1 Hz, and the ZZ, ZR, RZ, RR and TT components show much stronger wave energy than other components as expected. This poster discuss the different type of waves retrieved, the utility of the combination of borehole and surface observations, future development as well as the importance to compute the 9 components of the Green's tensor to better understand the wave field propriety with ambient noise.

  13. Covariant Noncommutative Field Theory

    Energy Technology Data Exchange (ETDEWEB)

    Estrada-Jimenez, S [Licenciaturas en Fisica y en Matematicas, Facultad de Ingenieria, Universidad Autonoma de Chiapas Calle 4a Ote. Nte. 1428, Tuxtla Gutierrez, Chiapas (Mexico); Garcia-Compean, H [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del IPN P.O. Box 14-740, 07000 Mexico D.F., Mexico and Centro de Investigacion y de Estudios Avanzados del IPN, Unidad Monterrey Via del Conocimiento 201, Parque de Investigacion e Innovacion Tecnologica (PIIT) Autopista nueva al Aeropuerto km 9.5, Lote 1, Manzana 29, cp. 66600 Apodaca Nuevo Leon (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato P.O. Box E-143, 37150 Leon Gto. (Mexico); Ramirez, C [Facultad de Ciencias Fisico Matematicas, Universidad Autonoma de Puebla, P.O. Box 1364, 72000 Puebla (Mexico)

    2008-07-02

    The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced.

  14. Covariant Noncommutative Field Theory

    International Nuclear Information System (INIS)

    Estrada-Jimenez, S.; Garcia-Compean, H.; Obregon, O.; Ramirez, C.

    2008-01-01

    The covariant approach to noncommutative field and gauge theories is revisited. In the process the formalism is applied to field theories invariant under diffeomorphisms. Local differentiable forms are defined in this context. The lagrangian and hamiltonian formalism is consistently introduced

  15. Understanding Vector Fields.

    Science.gov (United States)

    Curjel, C. R.

    1990-01-01

    Presented are activities that help students understand the idea of a vector field. Included are definitions, flow lines, tangential and normal components along curves, flux and work, field conservation, and differential equations. (KR)

  16. Magnetic Field Grid Calculator

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Properties Calculator will computes the estimated values of Earth's magnetic field(declination, inclination, vertical component, northerly...

  17. Gauge field copies

    International Nuclear Information System (INIS)

    Bollini, C.G.; Giambiagi, J.J.; Tiomno, J.

    1979-01-01

    The construction of field strength copies without any gauge constraint is discussed. Several examples are given, one of which is not only a field strength copy but also (at the same time) a 'current copy'. (author) [pt

  18. Cosmological magnetic fields - V

    Indian Academy of Sciences (India)

    Magnetic fields seem to be everywhere that we can look in the universe, from our own ... The field tensor is observer-independent, while the electric and magnetic .... based on string theory [11], in which vacuum fluctuations of the field are ...

  19. Unified field theory

    International Nuclear Information System (INIS)

    Prasad, R.

    1975-01-01

    Results of researches into Unified Field Theory over the past seven years are presented. The subject is dealt with in chapters entitled: the choice of affine connection, algebraic properties of the vector fields, field laws obtained from the affine connection based on the path integral method, application to quantum theory and cosmology, interpretation of physical theory in terms of geometry. (U.K.)

  20. Politics of aviation fields

    Science.gov (United States)

    Vivent, Jacques

    1922-01-01

    In short, the "politics of aviation" lies in a few propositions: the need of having as large a number of fields as possible and of sufficient area; the utilization of the larger part of the existing military fields; the selection of uncultivated or unproductive fields, whenever technical conditions permit; ability to disregard (save in exceptional cases) objections of an agricultural nature.

  1. Finite discrete field theory

    International Nuclear Information System (INIS)

    Souza, Manoelito M. de

    1997-01-01

    We discuss the physical meaning and the geometric interpretation of implementation in classical field theories. The origin of infinities and other inconsistencies in field theories is traced to fields defined with support on the light cone; a finite and consistent field theory requires a light-cone generator as the field support. Then, we introduce a classical field theory with support on the light cone generators. It results on a description of discrete (point-like) interactions in terms of localized particle-like fields. We find the propagators of these particle-like fields and discuss their physical meaning, properties and consequences. They are conformally invariant, singularity-free, and describing a manifestly covariant (1 + 1)-dimensional dynamics in a (3 = 1) spacetime. Remarkably this conformal symmetry remains even for the propagation of a massive field in four spacetime dimensions. We apply this formalism to Classical electrodynamics and to the General Relativity Theory. The standard formalism with its distributed fields is retrieved in terms of spacetime average of the discrete field. Singularities are the by-products of the averaging process. This new formalism enlighten the meaning and the problem of field theory, and may allow a softer transition to a quantum theory. (author)

  2. ZEPHYR - poloidal field system

    International Nuclear Information System (INIS)

    Seidel, U.

    1982-04-01

    The basics of the poloidal field system of the ZEPHYR experiment are considered. From the physical data the requirements for the poloidal field are derived. Hence an appropriate coil configuration consisting of coil locations and corresponding currents is obtained. A suitable electrical circuit feeding the coils is described. A preliminary assessment of the dynamic control of the poloidal field system is given. (orig.)

  3. Magnetic field line Hamiltonian

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1985-02-01

    The basic properties of the Hamiltonian representation of magnetic fields in canonical form are reviewed. The theory of canonical magnetic perturbation theory is then developed and applied to the time evolution of a magnetic field embedded in a toroidal plasma. Finally, the extension of the energy principle to tearing modes, utilizing the magnetic field line Hamiltonian, is outlined

  4. Omnigenous magnetic fields

    International Nuclear Information System (INIS)

    Stupakov, G.V.

    1982-01-01

    In omnigenous magnetic fields particles' drift surfaces coincide with plasma magnetic surfaces. In this paper we formulate equations of omnigenous magnetic fields in natural curvilinear coordinates. An analysis of fields which are omnigenous only in the paraxial approximation is presented. (author)

  5. Far field acceleration

    International Nuclear Information System (INIS)

    Fernow, R.C.

    1995-07-01

    Far fields are propagating electromagnetic waves far from their source, boundary surfaces, and free charges. The general principles governing the acceleration of charged particles by far fields are reviewed. A survey of proposed field configurations is given. The two most important schemes, Inverse Cerenkov acceleration and Inverse free electron laser acceleration, are discussed in detail

  6. Cosmic Magnetic Fields

    Science.gov (United States)

    Sánchez Almeida, J.; Martínez González, M. J.

    2018-05-01

    Magnetic fields play an important role in many astrophysical processes. They are difficult to detect and characterize since often their properties have to be inferred through interpreting the polarization of the light. Magnetic fields are also challenging to model and understand. Magnetized plasmas behave following highly non-linear differential equations having no general solution, so that every astrophysical problem represents a special case to be studied independently. Hence, magnetic fields are often an inconvenient subject which is overlooked or simply neglected (the elephant in the room, as they are dubbed in poster of the school). Such difficulty burdens the research on magnetic fields, which has evolved to become a very technical subject, with many small disconnected communities studying specific aspects and details. The school tried to amend the situation by providing a unifying view of the subject. The students had a chance to understand the behavior of magnetic fields in all astrophysical contexts, from cosmology to the Sun, and from starbursts to AGNs. The school was planed to present a balanced yet complete review of our knowledge, with excursions into the unknown to point out present and future lines of research. The subject of Cosmic Magnetic Fields was split into seven different topics: cosmic magnetic field essentials, solar magnetic fields, stellar magnetic fields, the role of magnetic fields on AGN feedback, magnetic fields in galaxies, magnetic fields in galaxy clusters and at larger scales, and primordial magnetic fields and magnetic fields in the early Universe. The corresponding lectures were delivered by seven well known and experienced scientists that have played key roles in the major advances of the field during the last years: F. Cattaneo, P. Judge, O. Kochukhov, R. Keppens, R. Beck, K. Dolag, and F. Finelli. Their lectures were recorded and are freely available at the IAC website: http://iactalks.iac.es/talks/serie/19.

  7. Quantum field theory

    International Nuclear Information System (INIS)

    Ryder, L.H.

    1985-01-01

    This introduction to the ideas and techniques of quantum field theory presents the material as simply as possible and is designed for graduate research students. After a brief survey of particle physics, the quantum theory of scalar and spinor fields and then of gauge fields, is developed. The emphasis throughout is on functional methods, which have played a large part in modern field theory. The book concludes with a bridge survey of ''topological'' objects in field theory and assumes a knowledge of quantum mechanics and special relativity

  8. Unitary field theories

    International Nuclear Information System (INIS)

    Bergmann, P.G.

    1980-01-01

    A problem of construction of the unitary field theory is discussed. The preconditions of the theory are briefly described. The main attention is paid to the geometrical interpretation of physical fields. The meaning of the conceptions of diversity and exfoliation is elucidated. Two unitary field theories are described: the Weyl conformic geometry and Calitzy five-dimensioned theory. It is proposed to consider supersymmetrical theories as a new approach to the problem of a unitary field theory. It is noted that the supergravitational theories are really unitary theories, since the fields figuring there do not assume invariant expansion

  9. Field emission electronics

    CERN Document Server

    Egorov, Nikolay

    2017-01-01

    This book is dedicated to field emission electronics, a promising field at the interface between “classic” vacuum electronics and nanotechnology. In addition to theoretical models, it includes detailed descriptions of experimental and research techniques and production technologies for different types of field emitters based on various construction principles. It particularly focuses on research into and production of field cathodes and electron guns using recently developed nanomaterials and carbon nanotubes. Further, it discusses the applications of field emission cathodes in new technologies such as light sources, flat screens, microwave and X-ray devices.

  10. Strong Magnetic Field Characterisation

    Science.gov (United States)

    2012-04-01

    an advertised surface field of approximately 0.5 T were used to supply the static magnetic field source. The disc magnet had a diameter of 50 mm and... colour bar indicates the magnetic field strength set to an arbitrary 0.25 T. The white area has a field >0.25 T. The size of the arrow is proportional...9 shows the magnetic field strength along a slice in the XZ plane. The colours represent the total UNCLASSIFIED 10 UNCLASSIFIED DSTO-TR-2699

  11. Classical field theory

    CERN Document Server

    Franklin, Joel

    2017-01-01

    Classical field theory, which concerns the generation and interaction of fields, is a logical precursor to quantum field theory, and can be used to describe phenomena such as gravity and electromagnetism. Written for advanced undergraduates, and appropriate for graduate level classes, this book provides a comprehensive introduction to field theories, with a focus on their relativistic structural elements. Such structural notions enable a deeper understanding of Maxwell's equations, which lie at the heart of electromagnetism, and can also be applied to modern variants such as Chern–Simons and Born–Infeld. The structure of field theories and their physical predictions are illustrated with compelling examples, making this book perfect as a text in a dedicated field theory course, for self-study, or as a reference for those interested in classical field theory, advanced electromagnetism, or general relativity. Demonstrating a modern approach to model building, this text is also ideal for students of theoretic...

  12. Earth's electric field

    International Nuclear Information System (INIS)

    Kelley, M.C.

    1978-01-01

    The earth becomes charged during thunderstorm activity and discharges through the weak conducting atmosphere. Balloon and rocket studies infer that a high altitude electric field penetrates virtually unattenuated through the atmosphere, at least as far as balloon heights. The field has two primary sources. At low and mid latitudes, interaction between the earth's magnetic field and the neutral wind creates electric fields. At latitudes above 60 0 , the high altitude electrical structure is dominated by the interaction between the solar wind and the earth's magnetic field. The auroral light is emitted by atmospheric atoms and molecules excited by electrons with potentials of many thousands volts. The potentials are induced by the solar wind. Recent satellite data shows that the electrons get this energy by passing through a localized electric field about 6000 km above the auroral zone. Several rocket and satellite experiments used to study the earth's electric field are discussed

  13. Forces in electromagnetic field and gravitational field

    OpenAIRE

    Weng, Zihua

    2008-01-01

    The force can be defined from the linear momentum in the gravitational field and electromagnetic field. But this definition can not cover the gradient of energy. In the paper, the force will be defined from the energy and torque in a new way, which involves the gravitational force, electromagnetic force, inertial force, gradient of energy, and some other new force terms etc. One of these new force terms can be used to explain why the solar wind varies velocity along the magnetic force line in...

  14. Continuum gauge fields from lattice gauge fields

    International Nuclear Information System (INIS)

    Goeckeler, M.; Kronfeld, A.S.; Schierholz, G.; Wiese, U.J.

    1993-01-01

    On the lattice some of the salient features of pure gauge theories and of gauge theories with fermions in complex representations of the gauge group seem to be lost. These features can be recovered by considering part of the theory in the continuum. The prerequisite for that is the construction of continuum gauge fields from lattice gauge fields. Such a construction, which is gauge covariant and complies with geometrical constructions of the topological charge on the lattice, is given in this paper. The procedure is explicitly carried out in the U(1) theory in two dimensions, where it leads to simple results. (orig.)

  15. Polarimetry of random fields

    Science.gov (United States)

    Ellis, Jeremy

    On temporal, spatial and spectral scales which are small enough, all fields are fully polarized. In the optical regime, however, instantaneous fields can rarely be examined, and, instead, only average quantities are accessible. The study of polarimetry is concerned with both the description of electromagnetic fields and the characterization of media a field has interacted with. The polarimetric information is conventionally presented in terms of second order field correlations which are averaged over the ensemble of field realizations. Motivated by the deficiencies of classical polarimetry in dealing with specific practical situations, this dissertation expands the traditional polarimetric approaches to include higher order field correlations and the description of fields fluctuating in three dimensions. In relation to characterization of depolarizing media, a number of fourth-order correlations are introduced in this dissertation. Measurements of full polarization distributions, and the subsequent evaluation of Stokes vector element correlations and Complex Degree of Mutual Polarization demonstrate the use of these quantities for material discrimination and characterization. Recent advancements in detection capabilities allow access to fields near their sources and close to material boundaries, where a unique direction of propagation is not evident. Similarly, there exist classical situations such as overlapping beams, focusing, or diffusive scattering in which there is no unique transverse direction. In this dissertation, the correlation matrix formalism is expanded to describe three dimensional electromagnetic fields, providing a definition for the degree of polarization of such a field. It is also shown that, because of the dimensionality of the problem, a second parameter is necessary to fully describe the polarimetric properties of three dimensional fields. Measurements of second-order correlations of a three dimensional field are demonstrated, allowing the

  16. Covariant electromagnetic field lines

    Science.gov (United States)

    Hadad, Y.; Cohen, E.; Kaminer, I.; Elitzur, A. C.

    2017-08-01

    Faraday introduced electric field lines as a powerful tool for understanding the electric force, and these field lines are still used today in classrooms and textbooks teaching the basics of electromagnetism within the electrostatic limit. However, despite attempts at generalizing this concept beyond the electrostatic limit, such a fully relativistic field line theory still appears to be missing. In this work, we propose such a theory and define covariant electromagnetic field lines that naturally extend electric field lines to relativistic systems and general electromagnetic fields. We derive a closed-form formula for the field lines curvature in the vicinity of a charge, and show that it is related to the world line of the charge. This demonstrates how the kinematics of a charge can be derived from the geometry of the electromagnetic field lines. Such a theory may also provide new tools in modeling and analyzing electromagnetic phenomena, and may entail new insights regarding long-standing problems such as radiation-reaction and self-force. In particular, the electromagnetic field lines curvature has the attractive property of being non-singular everywhere, thus eliminating all self-field singularities without using renormalization techniques.

  17. Partial Komori fields and imperative Komori fields

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2009-01-01

    This paper is concerned with the status of 1/0 and ways to deal with it. These matters are treated in the setting of Komori fields, also known as non-trivial cancellation meadows. Different viewpoints on the status of 1/0 exist in mathematics and theoretical computer science. We give a simple

  18. Nonlocal continuum field theories

    CERN Document Server

    2002-01-01

    Nonlocal continuum field theories are concerned with material bodies whose behavior at any interior point depends on the state of all other points in the body -- rather than only on an effective field resulting from these points -- in addition to its own state and the state of some calculable external field. Nonlocal field theory extends classical field theory by describing the responses of points within the medium by functionals rather than functions (the "constitutive relations" of classical field theory). Such considerations are already well known in solid-state physics, where the nonlocal interactions between the atoms are prevalent in determining the properties of the material. The tools developed for crystalline materials, however, do not lend themselves to analyzing amorphous materials, or materials in which imperfections are a major part of the structure. Nonlocal continuum theories, by contrast, can describe these materials faithfully at scales down to the lattice parameter. This book presents a unif...

  19. Simulated workplace neutron fields

    International Nuclear Information System (INIS)

    Lacoste, V.; Taylor, G.; Rottger, S.

    2011-01-01

    The use of simulated workplace neutron fields, which aim at replicating radiation fields at practical workplaces, is an alternative solution for the calibration of neutron dosemeters. They offer more appropriate calibration coefficients when the mean fluence-to-dose equivalent conversion coefficients of the simulated and practical fields are comparable. Intensive Monte Carlo modelling work has become quite indispensable for the design and/or the characterization of the produced mixed neutron/photon fields, and the use of Bonner sphere systems and proton recoil spectrometers is also mandatory for a reliable experimental determination of the neutron fluence energy distribution over the whole energy range. The establishment of a calibration capability with a simulated workplace neutron field is not an easy task; to date only few facilities are available as standard calibration fields. (authors)

  20. Nonequilibrium quantum field theories

    International Nuclear Information System (INIS)

    Niemi, A.J.

    1988-01-01

    Combining the Feynman-Vernon influence functional formalism with the real-time formulation of finite-temperature quantum field theories we present a general approach to relativistic quantum field theories out of thermal equilibrium. We clarify the physical meaning of the additional fields encountered in the real-time formulation of quantum statistics and outline diagrammatic rules for perturbative nonequilibrium computations. We derive a generalization of Boltzmann's equation which gives a complete characterization of relativistic nonequilibrium phenomena. (orig.)

  1. Organic magnetic field sensor

    Energy Technology Data Exchange (ETDEWEB)

    McCamey, Dane; Boehme, Christoph

    2017-01-24

    An organic, spin-dependent magnetic field sensor (10) includes an active stack (12) having an organic material with a spin-dependence. The sensor (10) also includes a back electrical contact (14) electrically coupled to a back of the active stack (12) and a front electrical contact (16) electrically coupled to a front of the active stack (12). A magnetic field generator (18) is oriented so as to provide an oscillating magnetic field which penetrates the active stack (12).

  2. Elementary quantum field theory

    International Nuclear Information System (INIS)

    Thirring, W.; Henley, E.M.

    1975-01-01

    The first section of the book deals with the mathematical and physical description of a quantum field with the Bose-Einstein statistics and discusses observables, invariants of the field, and inner symmetries. The second section develops further methods for solvable interactions of a quantum field with static source. Section 3 explains with the aid of the Chew-Low model especially pion-nucleon scattering, static properties of nucleons, electromagnetic phenomena, and nuclear forces. (BJ/LN) [de

  3. Wake field accelerators

    International Nuclear Information System (INIS)

    Wilson, P.B.

    1986-02-01

    In a wake field accelerator a high current driving bunch injected into a structure or plasma produces intense induced fields, which are in turn used to accelerate a trailing charge or bunch. The basic concepts of wake field acceleration are described. Wake potentials for closed cavities and periodic structures are derived, as are wake potentials on a collinear path with a charge distribution. Cylindrically symmetric structures excited by a beam in the form of a ring are considered

  4. Geomagnetic field, global pattern

    OpenAIRE

    Macmillan, Susan

    2011-01-01

    The geomagnetic field is generated in the fluid outer core region of the Earth by electrical currents flowing in the slowly moving molten iron. In addition to sources in the Earth’s core, the geomagnetic field observable on the Earth’s surface has sources in the crust and in the ionosphere and magnetosphere. The signal from the core dominates, accounting for over 95% of the field at the Earth’s surface. The geomagnetic field varies on a range of scales, both temporal and spatial; the...

  5. Effective quantum field theories

    International Nuclear Information System (INIS)

    Georgi, H.M.

    1993-01-01

    The most appropriate description of particle interactions in the language of quantum field theory depends on the energy at which the interactions are studied; the description is in terms of an ''effective field theory'' that contains explicit reference only to those particles that are actually important at the energy being studied. The various themes of the article are: local quantum field theory, quantum electrodynamics, new physics, dimensional parameters and renormalizability, socio-dynamics of particle theory, spontaneously broken gauge theories, scale dependence, grand unified and effective field theories. 2 figs

  6. Closed string field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1987-01-01

    A gauge invariant cubic action describing bosonic closed string field theory is constructed. The gauge symmetries include local spacetime diffeomorphisms. The conventional closed string spectrum and trilinear couplings are reproduced after spontaneous symmetry breaking. The action S is constructed from the usual ''open string'' field of ghost number minus one half. It is given by the associator of the string field product which is non-vanishing because of associativity anomalies. S does not describe open string propagation because open string states associate and can thereby be shifted away. A field theory of closed and open strings can be obtained by adding to S the cubic open string action. (orig.)

  7. Dielectrics in electric fields

    CERN Document Server

    Raju, Gorur G

    2003-01-01

    Discover nontraditional applications of dielectric studies in this exceptionally crafted field reference or text for seniors and graduate students in power engineering tracks. This text contains more than 800 display equations and discusses polarization phenomena in dielectrics, the complex dielectric constant in an alternating electric field, dielectric relaxation and interfacial polarization, the measurement of absorption and desorption currents in time domains, and high field conduction phenomena. Dielectrics in Electric Fields is an interdisciplinary reference and text for professionals and students in electrical and electronics, chemical, biochemical, and environmental engineering; physical, surface, and colloid chemistry; materials science; and chemical physics.

  8. Geomagnetic field of earth

    International Nuclear Information System (INIS)

    Delipetrev, Marjan; Delipetrev, Blagoj; Panovska, Sanja

    2008-01-01

    In this paper is introduced the theory of geomagnetic field of the Earth. A homogenous and isotropic sphere is taken for a model of Earth with a bar magnet at its center as a magnetic potential. The understanding of the real origin of geomagnetic field produced from differential rotation of inner core with respect to the outer core of Earth is here presented. Special attention is given to the latest observed data of the established net of geomagnetic repeat stations in the Republic of Macedonia. Finally, the maps of elements of geomagnetic field and the equation for calculation of normal magnetic field of Earth are provided. (Author)

  9. Fields, symmetries, and quarks

    International Nuclear Information System (INIS)

    Mosel, U.

    1989-01-01

    'Fields, symmetries, and quarks' covers elements of quantum field theory, symmetries, gauge field theories and phenomenological descriptions of hadrons, with special emphasis on topics relevant to nuclear physics. It is aimed at nuclear physicists in general and at scientists who need a working knowledge of field theory, symmetry principles of elementary particles and their interactions and the quark structure of hadrons. The book starts out with an elementary introduction into classical field theory and its quantization. As gauge field theories require a working knowledge of global symmetries in field theories this topic is then discussed in detail. The following part is concerned with the general structure of gauge field theories and contains a thorough discussion of the still less widely known features of Non-Abelian gauge field theories. Quantum Chromodynamics (QCD), which is important for the understanding of hadronic matter, is discussed in the next section together with the quark compositions of hadrons. The last two chapters give a detailed discussion of phenomenological bag-models. The MIT bag is discussed, so that all theoretical calculations can be followed step by step. Since in all other bag-models the calculational methods and steps are essentially identical, this chapter should enable the reader to actually perform such calculations unaided. A last chapter finally discusses the topological bag-models which have become quite popular over the last few years. (orig.)

  10. La fisiología en las películas: Coma, CO y la comprensión del intercambio gaseoso

    Directory of Open Access Journals (Sweden)

    Josep?E BAÑOS

    2016-01-01

    Full Text Available El presente artículo analiza la película Coma dirigida por Michael Chricton en 1978 e inspirada en la novela del mismo nombre de Robin Cook. Bajo el formato de thriller médico, muestra una serie de casos de coma que suceden en pacientes jóvenes y sanos sometidos a intervenciones quirúrgicas menores. La protagonista descubre que los afectados son traslados a una institución donde se les extraen los órganos para su comercio ilegal. También investiga la causa del coma, consecuencia de la intoxicación homicida con monóxido de carbono mientras los pacientes se encuentran en quirófano. La película tiene el interés docente de estimular la comprensión de los fenómenos de transporte de oxígeno por la hemoglobina, así como su afinidad por diversos gases, como el dióxido de carbono y el monóxido de carbono. Los estudiantes deben aplicar sus conocimientos fisiológicos para comprender cómo se realiza la intoxicación y sus características clínicas, así como las bases de su tratamiento.

  11. Methodology of adjustment point in the post treatment of gaseous effluents; Metodologia del punto de ajuste en el post tratamiento de efluentes gaseosos

    Energy Technology Data Exchange (ETDEWEB)

    Vizuet G, J.; Molina, G. [ININ, 52045 Ocoyoacac, Estado de Mexico (Mexico)]. e-mail: jvg@nuclear.inin.mx

    2005-07-01

    The methodology to determine the adjustment points of the monitoring system of gaseous discharges is based on the stipulations of the 10CFR20, which are expressed in terms of limit concentrations for the outstanding radionuclides, and of dose limits for the individuals members of the public. Besides the points of liberation properly said, like they are the chimneys of the reactor buildings and of turbine, the points of adjustment of the monitoring instrumentation that watches in real time the discharge of the Treatment system of output gases, to the HVAC of the waste building; they also undergo to the same methodology, with the approaches previously described. (Author)

  12. Effective field theories

    International Nuclear Information System (INIS)

    Mack, G.; Kalkreuter, T.; Palma, G.; Speh, M.

    1992-05-01

    Effective field theories encode the predictions of a quantum field theory at low energy. The effective theory has a fairly low utraviolet cutoff. As a result, loop corrections are small, at least if the effective action contains a term which is quadratic in the fields, and physical predictions can be read straight from the effective Lagrangean. Methods will be discussed how to compute an effective low energy action from a given fundamental action, either analytically or numerically, or by a combination of both methods. Basically, the idea is to integrate out the high frequency components of fields. This requires the choice of a 'blockspin', i.e. the specification af a low frequency field as a function of the fundamental fields. These blockspins will be fields of the effective field theory. The blockspin need not be a field of the same type as one of the fundamental fields, and it may be composite. Special features of blockspin in nonabelian gauge theories will be discussed in some detail. In analytical work and in multigrid updating schemes one needs interpolation kernels A from coarse to fine grid in addition to the averaging kernels C which determines the blockspin. A neural net strategy for finding optimal kernels is presented. Numerical methods are applicable to obtain actions of effective theories on lattices of finite volume. The special case of a 'lattice' with a single site (the constraint effective potential) is of particular interest. In a higgs model, the effective action reduces in this case to the free energy, considered as a function of a gauge covariant magnetization. Its shape determines the phase structure of the theory. Its loop expansion with and without gauge fields can be used to determine finite size corrections to numerical data. (orig.)

  13. twistors and gauge fields

    Directory of Open Access Journals (Sweden)

    A. G. Sergeev

    1986-01-01

    Full Text Available We describe briefly the basic ideas and results of the twistor theory. The main points: twistor representation of Minkowsky space, Penrose correspondence and its geometrical properties, twistor interpretation of linear massless fields, Yang-Mills fields (including instantons and monopoles and Einstein-Hilbert equations.

  14. Hyperfunction quantum field theory

    International Nuclear Information System (INIS)

    Nagamachi, S.; Mugibayashi, N.

    1976-01-01

    The quantum field theory in terms of Fourier hyperfunctions is constructed. The test function space for hyperfunctions does not contain C infinitely functios with compact support. In spite of this defect the support concept of H-valued Fourier hyperfunctions allows to formulate the locality axiom for hyperfunction quantum field theory. (orig.) [de

  15. Mean field games

    KAUST Repository

    Gomes, Diogo A.

    2014-01-06

    In this talk we will report on new results concerning the existence of smooth solutions for time dependent mean-field games. This new result is established through a combination of various tools including several a-priori estimates for time-dependent mean-field games combined with new techniques for the regularity of Hamilton-Jacobi equations.

  16. Quantum field theory

    CERN Document Server

    Sadovskii, Michael V

    2013-01-01

    This book discusses the main concepts of the Standard Model of elementary particles in a compact and straightforward way. The work illustrates the unity of modern theoretical physics by combining approaches and concepts of the quantum field theory and modern condensed matter theory. The inductive approach allows a deep understanding of ideas and methods used for solving problems in this field.

  17. Killing fields; The politics

    Energy Technology Data Exchange (ETDEWEB)

    Philips, Alasdair

    1990-02-01

    An overview considers the NRPB guidelines on possible health effects of low-level alternating electrical and magnetic fields and examines work by individuals on the hazards of microwave radiation, overhead power lines and childhood cancer, and the problems caused by electromagnetic fields at 50 Hz frequency. (U.K.).

  18. Moving Field Guides

    Science.gov (United States)

    Cassie Meador; Mark Twery; Meagan. Leatherbury

    2011-01-01

    The Moving Field Guides (MFG) project is a creative take on site interpretation. Moving Field Guides provide an example of how scientific and artistic endeavors work in parallel. Both begin with keen observations that produce information that must be analyzed, understood, and interpreted. That interpretation then needs to be communicated to others to complete the...

  19. Respirator field performance factors

    International Nuclear Information System (INIS)

    Skaggs, B.J.; DeField, J.D.; Strandberg, S.W.; Sutcliffe, C.R.

    1985-01-01

    The Industrial Hygiene Group assisted OSHA and the NRC in measurements of respirator performance under field conditions. They reviewed problems associated with sampling aerosols within the respirator in order to determine fit factors (FFs) or field performance factor (FPF). In addition, they designed an environmental chamber study to determine the effects of temperature and humidity on a respirator wearer

  20. Magnetic field on board

    International Nuclear Information System (INIS)

    Estevez Radio, H.; Fernandez Arenal, C.A.

    1995-01-01

    Here, the calculation of the magnetic field on board ships is performed, using matrix calculus, in a similar way as when the magnetic field in matter is studied. Thus the final formulas are written in a more compact form and they are obtained through a simpler way, more suitable for the university education. (Author)

  1. Pregnancy and electromagnetic fields

    International Nuclear Information System (INIS)

    Bisseriex, Ch.; Laurent, P.; Cabaret, Ph.; Bonnet, C.; Marteau, E.; Le Berre, G.; Tirlemont, S.; Castro, H.; Becker, A.; Demaret, Ph.; Donati, M.; Ganem, Y.; Moureaux, P.

    2011-07-01

    This document briefly indicates the status of knowledge regarding the effect of magnetic fields on biological tissues and pregnancy, outlines the lack of data on some frequencies and the weakness of studies on long term effects on child development. It evokes the issue of exposure assessment and that of identification of workstations exposed to electromagnetic fields

  2. Magnetic field line Hamiltonian

    International Nuclear Information System (INIS)

    Boozer, A.H.

    1984-03-01

    The magnetic field line Hamiltonian and the associated canonical form for the magnetic field are important concepts both for understanding toroidal plasma physics and for practical calculations. A number of important properties of the canonical or Hamiltonian representation are derived and their importance is explained

  3. Fields From Markov Chains

    DEFF Research Database (Denmark)

    Justesen, Jørn

    2005-01-01

    A simple construction of two-dimensional (2-D) fields is presented. Rows and columns are outcomes of the same Markov chain. The entropy can be calculated explicitly.......A simple construction of two-dimensional (2-D) fields is presented. Rows and columns are outcomes of the same Markov chain. The entropy can be calculated explicitly....

  4. Pulsed electric fields

    Science.gov (United States)

    The concept of pulsed electric fields (PEF) was first proposed in 1967 to change the behavior or microorganisms. The electric field phenomenon was identified as membrane rupture theory in the 1980s. Increasing the membrane permeability led to the application of PEF assisted extraction of cellular co...

  5. MAGNETIC FIELDS OF STARS

    OpenAIRE

    Bychkov, V. D.; Bychkova, L. V.; Madej, J.

    2008-01-01

    Now it is known about 1212 stars of the main sequence and giants (from them 610 stars - it is chemically peculiarity (CP) stars) for which direct measurements of magnetic fields were spent (Bychkov et al.,2008). Let's consider, what representations were generated about magnetic fields (MT) of stars on the basis of available observations data.

  6. Quantization and nonlocal fields

    International Nuclear Information System (INIS)

    Kolerov, G.I.

    1977-01-01

    A relation between the postulate of causality and quatization conditions is considered for the scalar field. A formalism of outer forms given on the functional space is used. A current commutator is obtained for nonlogical fields in the space-like region

  7. Mean field games

    KAUST Repository

    Gomes, Diogo A.

    2014-01-01

    In this talk we will report on new results concerning the existence of smooth solutions for time dependent mean-field games. This new result is established through a combination of various tools including several a-priori estimates for time-dependent mean-field games combined with new techniques for the regularity of Hamilton-Jacobi equations.

  8. Unified field theory

    International Nuclear Information System (INIS)

    Vollendorf, F.

    1976-01-01

    A theory is developed in which the gravitational as well as the electromagnetic field is described in a purely geometrical manner. In the case of a static central symmetric field Newton's law of gravitation and Schwarzschild's line element are derived by means of an action principle. The same principle leads to Fermat's law which defines the world lines of photons. (orig.) [de

  9. Pregnant Field Students' Guilt

    Science.gov (United States)

    Baum, Nehami

    2006-01-01

    This study examined guilt feelings among social work students who were pregnant for the first time during field work training. Semi-structured interviews were conducted either in the 9th month (n=5) or 2-12 months after delivery (n=5). Content analysis revealed 6 main triggers, illustrated by excerpts, which stimulated field students' guilt…

  10. Prehnite-pumpellyite facies metamorphism in the Cenozoic Abanico Formation, Andes of central Chile (33°50'S: chemical and scale controls on mineral assemblages, reaction progress and the equilibrium state Metamorfismo de facies prehnita-pumpellyita en la Formación Abanico del Cenozoico, Andes centrales de Chile (33°50'S: controles químicos y de escala sobre las asociaciones minerales, el progreso de la reacción y el estado de equilibrio

    Directory of Open Access Journals (Sweden)

    Marcia Muñoz

    2010-01-01

    los Bueyes, Cordillera Principal al este de Santiago (33°50'S, aflora una serie volcánica del Oligoceno Superior-Mioceno Inferior perteneciente a la Formación Abanico (Eoceno Tardío-Mioceno Temprano. Las sucesiones de roca expuestas en ambas areas, de ca. 3.300 m de espesor total, fueron afectadas por metamorfismo no deformativo de muy bajo grado en facies prehnita-pumpellyita. Esto está representado en el desarrollo extensivo de arreglos de minerales secundarios formados por epidota, inter-estratificados de clorita-esmectita, albita, cuarzo, mica blanca, y titanita. Estos arreglos minerales contienen además pumpellyita, prehnita o prehnita+actinolita en algunas muestras. Las características químicas tales como una baja variabilidad composicional de los interestratificados de clorita-esmectita y actinolita independientemente del dominio donde se hospedan estas fases, junto con una alta proporción de capas de clorita en las primeras, sugieren que estas fases representan cercanamente la composición efectiva de la roca total. Por el contrario, la composición de las pum-pellyitas muestra una mayor variabilidad y un fuerte control del metadominio donde éstas se desarrollan evidenciando una baja cinética de equilibrio y dejando sólo a aquellas desarrolladas en la matriz como formadas bajo un control composicional efectivo de la roca total. Los arreglos minerales de ambas areas muestran evidencias de haberse formado bajo un mismo evento metamórñco bajo el cual las reacciones se han desarrollado de manera equivalente. Aún así se reconocen diferencias químicas locales que controlan este proceso. Una mayor concentración de CO2 en los fluidos durante el metamorfismo en el area de El Volcán, con respecto al area de Rodeo de los Bueyes, se ve representada en la presencia escasa de prehnita, y abundante de calcita, en sus asociaciones minerales. La presion y temperatura de este evento metamórfico han sido gruesamente estimadas en valores inferiores a 2-3 kbar

  11. Electromagnetic fields in biological systems

    National Research Council Canada - National Science Library

    Lin, James C

    2012-01-01

    "Focusing on exposure, induced fields, and absorbed energy, this volume covers the interaction of electromagnetic fields and waves with biological systems, spanning static fields to terahertz waves...

  12. The Coriolis field

    Science.gov (United States)

    Costa, L. Filipe; Natário, José

    2016-05-01

    We present a pedagogical discussion of the Coriolis field, emphasizing its not-so-well-understood aspects. We show that this field satisfies the field equations of the so-called Newton-Cartan theory, a generalization of Newtonian gravity that is covariant under changes of arbitrarily rotating and accelerated frames. Examples of solutions of this theory are given, including the Newtonian analogue of the Gödel universe. We discuss how to detect the Coriolis field by its effect on gyroscopes, of which the gyrocompass is an example. Finally, using a similar framework, we discuss the Coriolis field generated by mass currents in general relativity, and its measurement by the gravity probe B and LAGEOS/LARES experiments.

  13. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...... or meromorphic (allowing poles as singularities) functions. There already exists a well-developed theory for iterative holomorphic dynamical systems, and successful relations found between iteration theory and flows of vector fields have been one of the main motivations for the recent interest in holomorphic...... vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...

  14. Finite fields and applications

    CERN Document Server

    Mullen, Gary L

    2007-01-01

    This book provides a brief and accessible introduction to the theory of finite fields and to some of their many fascinating and practical applications. The first chapter is devoted to the theory of finite fields. After covering their construction and elementary properties, the authors discuss the trace and norm functions, bases for finite fields, and properties of polynomials over finite fields. Each of the remaining chapters details applications. Chapter 2 deals with combinatorial topics such as the construction of sets of orthogonal latin squares, affine and projective planes, block designs, and Hadamard matrices. Chapters 3 and 4 provide a number of constructions and basic properties of error-correcting codes and cryptographic systems using finite fields. Each chapter includes a set of exercises of varying levels of difficulty which help to further explain and motivate the material. Appendix A provides a brief review of the basic number theory and abstract algebra used in the text, as well as exercises rel...

  15. Dual double field theory

    Energy Technology Data Exchange (ETDEWEB)

    Bergshoeff, Eric A. [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Hohm, Olaf [Simons Center for Geometry and Physics, Stony Brook University,Stony Brook, NY 11794-3636 (United States); Penas, Victor A. [Centre for Theoretical Physics, University of Groningen,Nijenborgh 4, 9747 AG Groningen (Netherlands); Riccioni, Fabio [INFN - Sezione di Roma, Dipartimento di Fisica, Università di Roma “La Sapienza”,Piazzale Aldo Moro 2, 00185 Roma (Italy)

    2016-06-06

    We present the dual formulation of double field theory at the linearized level. This is a classically equivalent theory describing the duals of the dilaton, the Kalb-Ramond field and the graviton in a T-duality or O(D,D) covariant way. In agreement with previous proposals, the resulting theory encodes fields in mixed Young-tableau representations, combining them into an antisymmetric 4-tensor under O(D,D). In contrast to previous proposals, the theory also requires an antisymmetric 2-tensor and a singlet, which are not all pure gauge. The need for these additional fields is analogous to a similar phenomenon for “exotic' dualizations, and we clarify this by comparing with the dualizations of the component fields. We close with some speculative remarks on the significance of these observations for the full non-linear theory yet to be constructed.

  16. Field theory and strings

    International Nuclear Information System (INIS)

    Bonara, L.; Cotta-Ramusino, P.; Rinaldi, M.

    1987-01-01

    It is well-known that type I and heterotic superstring theories have a zero mass spectrum which correspond to the field content of N=1 supergravity theory coupled to supersymmetric Yang-Mills theory in 10-D. The authors study the field theory ''per se'', in the hope that simple consistency requirements will determine the theory completely once one knows the field content inherited from string theory. The simplest consistency requirements are: N=1 supersymmetry; and absence of chiral anomalies. This is what the authors discuss in this paper here leaving undetermined the question of the range of validity of the resulting field theory. As is known, a model of N=1 supergravity (SUGRA) coupled to supersymmetric Yang-Mills (SYM) theory was known in the form given by Chapline and Manton. The coupling of SUGRA to SYM was determined by the definition of the ''field strength'' 3-form H in this paper

  17. Narrowing the field

    DEFF Research Database (Denmark)

    Knudsen, Bo Nissen

    characteristics and the sequence of information in the series. Adding to the challenge is the macrostructural variation: The areas covered in printed form are covered with shifting principles of selecting the names to be published. Finding the right balance between letting the algorithms structure this complex....... As of now, no less than 45 different database fields have been found necessary to structure the information found in a single place-name entry – some fields mandatory, some nonmandatory. And using a relational database structure, some fields have multiple occurrences within one entry (i.e. multiple source...... forms for one entry a.s.f.). Having made the conscious decision to split up the information into so many categories (i.e. fields) – instead of employing a broad 'other information' field – sophisticated algorithms have been developed in order to identify information category from typographical...

  18. Magnetic fields in cosmology

    International Nuclear Information System (INIS)

    Madsen, M.S.

    1989-01-01

    The possible role of a large-scale relic magnetic field in the history of the Universe is considered. The perturbation of the cosmic microwave back-ground radiation on large angular scales due to a homogeneous magnetic field is estimated in a simple relativistic model. This allows corresponding limits to be placed on the magnitude of any such large-scale relic magnetic field at the present time. These limits are essentially the strongest which can be set on the largest scales. A corresponding bound is obtained by use of the requirement that the field should not spoil the predictions of primordial nucleosynthesis. It is noted that the existence of large-scale cosmic magnetic fields would circumvent the limits previously set - also on the basis of nucleosynthesis considerations - on the large-scale anisotropy now present in the Universe. (author)

  19. Complex Polynomial Vector Fields

    DEFF Research Database (Denmark)

    Dias, Kealey

    vector fields. Since the class of complex polynomial vector fields in the plane is natural to consider, it is remarkable that its study has only begun very recently. There are numerous fundamental questions that are still open, both in the general classification of these vector fields, the decomposition...... of parameter spaces into structurally stable domains, and a description of the bifurcations. For this reason, the talk will focus on these questions for complex polynomial vector fields.......The two branches of dynamical systems, continuous and discrete, correspond to the study of differential equations (vector fields) and iteration of mappings respectively. In holomorphic dynamics, the systems studied are restricted to those described by holomorphic (complex analytic) functions...

  20. Gauge fields and inflation

    Science.gov (United States)

    Maleknejad, A.; Sheikh-Jabbari, M. M.; Soda, J.

    2013-07-01

    The isotropy and homogeneity of the cosmic microwave background (CMB) favors “scalar driven” early Universe inflationary models. However, gauge fields and other non-scalar fields are far more common at all energy scales, in particular at high energies seemingly relevant to inflation models. Hence, in this review we consider the role and consequences, theoretical and observational, that gauge fields can have during the inflationary era. Gauge fields may be turned on in the background during inflation, or may become relevant at the level of cosmic perturbations. There have been two main classes of models with gauge fields in the background, models which show violation of the cosmic no-hair theorem and those which lead to isotropic FLRW cosmology, respecting the cosmic no-hair theorem. Models in which gauge fields are only turned on at the cosmic perturbation level, may source primordial magnetic fields. We also review specific observational features of these models on the CMB and/or the primordial cosmic magnetic fields. Our discussions will be mainly focused on the inflation period, with only a brief discussion on the post inflationary (p)reheating era. Large field models: The initial value of the inflaton field is large, generically super-Planckian, and it rolls slowly down toward the potential minimum at smaller φ values. For instance, chaotic inflation is one of the representative models of this class. The typical potential of large-field models has a monomial form as V(φ)=V0φn. A simple analysis using the dynamical equations reveals that for number of e-folds Ne larger than 60, we require super-Planckian initial field values,5φ0>3M. For these models typically ɛ˜η˜Ne-1. Small field models: Inflaton field is initially small and slowly evolves toward the potential minimum at larger φ values. The small field models are characterized by the following potential V(φ)=V0(1-(), which corresponds to a Taylor expansion about the origin, but more realistic

  1. The earth's magnetic field

    International Nuclear Information System (INIS)

    Merrill, R.T.

    1983-01-01

    After a historical introduction in Chapter 1, the more traditional aspects of geomagnetism relating to the present field and historical observations are presented in Chapter 2. The various methods and techniques and theoretical background of palaeomagnetism are given in Chapter 3. Chapters 4, 5 and 6 present the results of palaeomagnetic and archaeomagnetic studies in three topics. Chapter 4 relates to studies of the geomagnetic field roughly back to about 50,000 years ago. Chapter 5 is about reversals of the geomagnetic field and Chapter 6 presents studies of the field for times older than 50,000 years and on the geological time scale of millions or hundreds of millions of years. Chapters 7, 8 and 9 provide insight into dynamo theory. Chapter 7 is essentially a non-mathematical attempt to explain the physical basis of dynamo theories to palaeomagnetists. This is followed in Chapter 8 by a more advanced theoretical treatment. Chapter 9 explains theoretical aspects of secular variation and the origin of reversals of the geomagnetic field. Chapter 10 is our attempt to relate theory to experiment and vice versa. The final two chapters consider the magnetic fields of the moon, sun, planets and meteorites, in an attempt to determine the necessary and sufficient conditions for magnetic field generation in large solar system bodies. (author)

  2. The Juno Magnetic Field Investigation

    DEFF Research Database (Denmark)

    Connerney, J. E. P.; Benn, Mathias; Bjarnø, Jonas Bækby

    2017-01-01

    The Juno Magnetic Field investigation (MAG) characterizes Jupiter’s planetary magnetic field and magnetosphere, providing the first globally distributed and proximate measurements of the magnetic field of Jupiter. The magnetic field instrumentation consists of two independent magnetometer sensor ...

  3. Robotics Potential Fields

    Directory of Open Access Journals (Sweden)

    Jordi Lucero

    2009-01-01

    Full Text Available This problem was to calculate the path a robot would take to navigate an obstacle field and get to its goal. Three obstacles were given as negative potential fields which the robot avoided, and a goal was given a positive potential field that attracted the robot. The robot decided each step based on its distance, angle, and influence from every object. After each step, the robot recalculated and determined its next step until it reached its goal. The robot's calculations and steps were simulated with Microsoft Excel.

  4. International Geomagnetic Reference Field

    DEFF Research Database (Denmark)

    Finlay, Chris; Maus, S.; Beggan, C. D.

    2010-01-01

    The eleventh generation of the International Geomagnetic Reference Field (IGRF) was adopted in December 2009 by the International Association of Geomagnetism and Aeronomy Working Group V‐MOD. It updates the previous IGRF generation with a definitive main field model for epoch 2005.0, a main field...... model for epoch 2010.0, and a linear predictive secular variation model for 2010.0–2015.0. In this note the equations defining the IGRF model are provided along with the spherical harmonic coefficients for the eleventh generation. Maps of the magnetic declination, inclination and total intensity...

  5. Room Acoustical Fields

    CERN Document Server

    Mechel, Fridolin

    2013-01-01

    This book presents the theory of room acoustical fields and revises the Mirror Source Methods for practical computational use, emphasizing the wave character of acoustical fields.  The presented higher methods include the concepts of “Mirror Point Sources” and “Corner sources which allow for an excellent approximation of complex room geometries and even equipped rooms. In contrast to classical description, this book extends the theory of sound fields describing them by their complex sound pressure and the particle velocity. This approach enables accurate descriptions of interference and absorption phenomena.

  6. On the Schrodinger field

    International Nuclear Information System (INIS)

    Takahashi, Y.

    1986-01-01

    A brief but systematic discussion of the Schrodinger field is presented from the view point of quantized field theory. It is pointed out that the local momentum conservation equation is not of the usual continuity equation type when two-body potential interaction is presented and nevertheless the total momentum is globally conserved. The Schrodinger equation can be cast into a multicomponent equation containing only first order derivatives, depending on its spin contents. In case of spin 1/2, the g-factor is shown to be 2 even in purely non-relativistic Schrodinger field, in contrast with the general belief that g=2 is a relativistic effect

  7. Ridge and Furrow Fields

    DEFF Research Database (Denmark)

    Møller, Per Grau

    2016-01-01

    Ridge and furrow is a specific way of ploughing which makes fields of systematic ridges and furrows like a rubbing washboard. They are part of an overall openfield system, but the focus in this paper is on the functionality of the fields. There are many indications that agro-technological reasons...... systems and the establishment of basic structures like villages (with churches) and townships and states (in northern Europe). The fields can be considered as a resilient structure lasting for 800 years, along with the same basic physical structures in society....

  8. Geophysical Field Theory

    International Nuclear Information System (INIS)

    Eloranta, E.

    2003-11-01

    The geophysical field theory includes the basic principles of electromagnetism, continuum mechanics, and potential theory upon which the computational modelling of geophysical phenomena is based on. Vector analysis is the main mathematical tool in the field analyses. Electrostatics, stationary electric current, magnetostatics, and electrodynamics form a central part of electromagnetism in geophysical field theory. Potential theory concerns especially gravity, but also electrostatics and magnetostatics. Solid state mechanics and fluid mechanics are central parts in continuum mechanics. Also the theories of elastic waves and rock mechanics belong to geophysical solid state mechanics. The theories of geohydrology and mass transport form one central field theory in geophysical fluid mechanics. Also heat transfer is included in continuum mechanics. (orig.)

  9. Field Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Field Research Facility (FRF) located in Duck, N.C. was established in 1977 to support the U.S. Army Corps of Engineers' coastal engineering mission. The FRF is...

  10. Reversed field pinch diagnostics

    International Nuclear Information System (INIS)

    Weber, P.G.

    1986-01-01

    The Reversed Field Pinch (RFP) is a toroidal, axisymmetric magnetic confinement configuration characterized by a magnetic field configuration in which the toroidal magnetic field is of similar strength to the poloidal field, and is reversed at the edge compared to the center. The RFP routinely operates at high beta, and is a strong candidate for a compact fusion device. Relevant attributes of the configuration will be presented, together with an overview of present and planned experiments and their diagnostics. RFP diagnostics are in many ways similar to those of other magnetic confinement devices (such as tokamaks); these lectures will point out pertinent differences, and will present some diagnostics which provide special insights into unique attributes of the RFP

  11. Algebraic conformal field theory

    International Nuclear Information System (INIS)

    Fuchs, J.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica

    1991-11-01

    Many conformal field theory features are special versions of structures which are present in arbitrary 2-dimensional quantum field theories. So it makes sense to describe 2-dimensional conformal field theories in context of algebraic theory of superselection sectors. While most of the results of the algebraic theory are rather abstract, conformal field theories offer the possibility to work out many formulae explicitly. In particular, one can construct the full algebra A-bar of global observables and the endomorphisms of A-bar which represent the superselection sectors. Some explicit results are presented for the level 1 so(N) WZW theories; the algebra A-bar is found to be the enveloping algebra of a Lie algebra L-bar which is an extension of the chiral symmetry algebra of the WZW theory. (author). 21 refs., 6 figs

  12. Earth's Magnetic Field

    DEFF Research Database (Denmark)

    This volume provides a comprehensive view on the different sources of the geomagnetic field both in the Earth’s interior and from the field’s interaction with the terrestrial atmosphere and the solar wind. It combines expertise from various relevant areas of geomagnetic and near Earth space...... research with the aim to better characterise the state and dynamics of Earth’s magnetic field. Advances in the exploitation of geomagnetic observations hold a huge potential not only for an improved quantitative description of the field source but also for a better understanding of the underlying processes...... and space observations, and on state-of-the-art empirical models and physics-based simulations. Thus, it provides an in-depth overview over recent achievements, current limitations and challenges, and future opportunities in the field of geomagnetism and space sciences....

  13. The master field revisited

    International Nuclear Information System (INIS)

    Gopakumar, R.

    1996-01-01

    We review recent work on the master field in large N theories. In particular the mathematical framework appropriate for its construction is sketched. The calculational utility of this framework is demonstrated in the case of QCD 2 . (orig.)

  14. Field Geology/Processes

    Science.gov (United States)

    Allen, Carlton; Jakes, Petr; Jaumann, Ralf; Marshall, John; Moses, Stewart; Ryder, Graham; Saunders, Stephen; Singer, Robert

    1996-01-01

    The field geology/process group examined the basic operations of a terrestrial field geologist and the manner in which these operations could be transferred to a planetary lander. Four basic requirements for robotic field geology were determined: geologic content; surface vision; mobility; and manipulation. Geologic content requires a combination of orbital and descent imaging. Surface vision requirements include range, resolution, stereo, and multispectral imaging. The minimum mobility for useful field geology depends on the scale of orbital imagery. Manipulation requirements include exposing unweathered surfaces, screening samples, and bringing samples in contact with analytical instruments. To support these requirements, several advanced capabilities for future development are recommended. Capabilities include near-infrared reflectance spectroscopy, hyper-spectral imaging, multispectral microscopy, artificial intelligence in support of imaging, x ray diffraction, x ray fluorescence, and rock chipping.

  15. Maine Field Station

    Data.gov (United States)

    Federal Laboratory Consortium — In 2000 NOAA's National Marine Fisheries Service established the Maine Field Station in Orono, ME to have more direct involvement in the conservation of the living...

  16. Three dimensional field computation

    International Nuclear Information System (INIS)

    Trowbridge, C.W.

    1981-06-01

    Recent research work carried out at Rutherford and Appleton Laboratories into the Computation of Electromagnetic Fields is summarised. The topics covered include algorithms for integral and differential methods for the solution of 3D magnetostatic fields, comparison of results with experiment and an investigation into the strengths and weaknesses of both methods for an analytic problem. The paper concludes with a brief summary of the work in progress on the solution of 3D eddy currents using differential finite elements. (author)

  17. Magnetic field of Mercury

    International Nuclear Information System (INIS)

    Jackson, D.J.; Beard, D.B.

    1977-01-01

    The geomagnetic field, suitably scaled down and parameterized, is shown to give a very good fit to the magnetic field measurements taken on the first and third passes of the Mariner 10 space probe past Mercury. The excellence of the fit to a reliable planetary magnetospheric model is good evidence that the Mercury magnetosphere is formed by a simple, permanent, intrinsic planetary magnetic field distorted by the effects of the solar wind. The parameters used for a best fit to all the data are (depending slightly on the choice of data) 2.44--2.55 for the ratio of Mercury's magnetic field strength at the subsolar point to that of the earth's subsolar point field (this results in a dipole moment of 170 γR/sub M/ 3 (R/sub M/ is Mercury Radius), i.e., 2.41 x 10 22 G cm 3 in the same direction as the earth's dipole), approx.-113 γR/sub M/ 4 for the planetary quadrupole moment parallel to the dipole moment, 10degree--17degree for the tilt of the planet dipole toward the sun, 4.5degree for the tilt of the dipole toward dawn, and 2.5degree--7.6degree aberration angle for the shift in the tail axis from the planet-sun direction because of the planet's orbital velocity. The rms deviation overall for the entire data set compared with the theoretical fitted model for the magnetic field strength was 17 γ (approx.4% of the maximum field measured). If the data from the first pass that show presumed strong time variations are excluded, the overall rms deviation for the field magnitude is only 10 γ

  18. Magnetic field dosimeter development

    International Nuclear Information System (INIS)

    Lemon, D.K.; Skorpik, J.R.; Eick, J.L.

    1980-09-01

    In recent years there has been increased concern over potential health hazards related to exposure of personnel to magnetic fields. If exposure standards are to be established, then a means for measuring magnetic field dose must be available. To meet this need, the Department of Energy has funded development of prototype dosimeters at the Battelle Pacific Northwest Laboratory. This manual reviews the principle of operation of the dosimeter and also contains step-by-step instructions for its operation

  19. DSM-5 field survey

    DEFF Research Database (Denmark)

    Lochner, Christine; Grant, Jon E; Odlaug, Brian Lawrence

    2012-01-01

    The aim of this multisite field survey was to examine the DSM-IV-TR criteria, proposed DSM-5 diagnostic criteria, as well as a number of possible additional diagnostic criteria, in patients with hair-pulling disorder (HPD, or trichotillomania).......The aim of this multisite field survey was to examine the DSM-IV-TR criteria, proposed DSM-5 diagnostic criteria, as well as a number of possible additional diagnostic criteria, in patients with hair-pulling disorder (HPD, or trichotillomania)....

  20. Collective field accelerator

    International Nuclear Information System (INIS)

    Luce, J.S.

    1978-01-01

    A collective field accelerator which operates with a vacuum diode and utilizes a grooved cathode and a dielectric anode that operates with a relativistic electron beam with a ν/γ of approx. 1, and a plurality of dielectric lenses having an axial magnetic field thereabout to focus the collectively accelerated electrons and ions which are ejected from the anode. The anode and lenses operate as unoptimized r-f cavities which modulate and focus the beam

  1. Controlling magnetic field profiles

    International Nuclear Information System (INIS)

    Freeman, J.R.

    1979-04-01

    A method for designing solenoid magnets with controlled field profiles is discussed. The method, originated by D.B. Montgomery, minimizes both the field errors and the power consumption. An NOS time-sharing computer program for the CDC-6600, entitled MAGCOR, was constructed to provide an interactive magnet design capability. Results obtained during the design of magnets for a radial line electron accelerator are presented. 9 figures

  2. Gauge field theories

    International Nuclear Information System (INIS)

    Leite Lopes, J.

    1981-01-01

    The book is intended to explain, in an elementary way, the basic notions and principles of gauge theories. Attention is centred on the Salem-Weinberg model of electro-weak interactions, as well as neutrino-lepton scattering and the parton model. Classical field theory, electromagnetic, Yang-Mills and gravitational gauge fields, weak interactions, Higgs mechanism and the SU(5) model of grand unification are also discussed. (U.K.)

  3. Radial Field Piezoelectric Diaphragms

    Science.gov (United States)

    Bryant, R. G.; Effinger, R. T., IV; Copeland, B. M., Jr.

    2002-01-01

    A series of active piezoelectric diaphragms were fabricated and patterned with several geometrically defined Inter-Circulating Electrodes "ICE" and Interdigitated Ring Electrodes "ICE". When a voltage potential is applied to the electrodes, the result is a radially distributed electric field that mechanically strains the piezoceramic along the Z-axis (perpendicular to the applied electric field). Unlike other piezoelectric bender actuators, these Radial Field Diaphragms (RFDs) strain concentrically yet afford high displacements (several times that of the equivalent Unimorph) while maintaining a constant circumference. One of the more intriguing aspects is that the radial strain field reverses itself along the radius of the RFD while the tangential strain remains relatively constant. The result is a Z-deflection that has a conical profile. This paper covers the fabrication and characterization of the 5 cm. (2 in.) diaphragms as a function of poling field strength, ceramic thickness, electrode type and line spacing, as well as the surface topography, the resulting strain field and displacement as a function of applied voltage at low frequencies. The unique features of these RFDs include the ability to be clamped about their perimeter with little or no change in displacement, the environmentally insulated packaging, and a highly repeatable fabrication process that uses commodity materials.

  4. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    Linford, R.K.; Armstrong, W.T.; Platts, D.A.; Sherwood, E.G.

    1978-01-01

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centers the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFC's with a major radius R = 2-6 cm, minor radius a approximately 2 cm, and a total length l approximately 35 cm. The observed temperatures are T/sub e/ approximately 100 eV and T/sub i/ = 150-350 eV with a peak density n approximately 2 x 10 15 cm -3 . After the plasma reaches equilibrium, the RFC remains stable for up to 30 μs followed by the rapid growth of the rotational m = 2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behavior of the m = 2 mode qualitatively agrees with the theoretically predicted instability for rotational velocities exceeding some critical value

  5. Field reversal experiments (FRX)

    International Nuclear Information System (INIS)

    Linford, R.K.; Armstrong, W.T.; Platts, D.A.; Sherwood, E.G.

    1979-01-01

    The equilibrium, confinement, and stability properties of the reversed-field configuration (RFC) are being studied in two theta-pinch facilities. The RFC is an elongated toroidal plasma confined in a purely poloidal field geometry. The open field lines of the linear theta pinch support the closed-field RFC much like the vertical field centres the toroidal plasma in a tokamak. Depending on stability and confinement properties, the RFC might be used to greatly reduce the axial losses in linear fusion devices such as mirrors, theta pinches, and liners. The FRX systems produce RFCs with a major radius R=2-6cm, a minor radius a approximately 2cm, and a total length l approximately 35cm. The observed temperatures are Tsub(e) approximately 100eV and Tsub(i)=150-350eV with a peak density n approximately 2x10 15 cm -3 . After the plasma has reached equilibrium, the RFC remains stable for up to 30μs, followed by the rapid growth of the rotational m=2 instability, which terminates the confinement. During the stable equilibrium, the particle and energy confinement times are more than 10 times longer than in an open-field system. The behaviour of the m=2 mode agrees qualitatively with the theoretically predicted instability for rotational velocities exceeding some critical value. (author)

  6. Magnetic field screens

    International Nuclear Information System (INIS)

    Mansfield, P.; Turner, R.; Chapman, B.L.W.; Bowley, R.M.

    1990-01-01

    A screen for a magnetic coil, for producing, for example, a homogeneous, gradient or RF field in nuclear magnetic resonance imaging, is described. It is provided by surround the coil with a set of electrical conductors. The currents within the conductors are controlled in such a manner that the field is neutralised in a specific region of space. The current distribution within the conductors is determined by calculating the current within a hypothetical superconductive shield which would have the effect of neutralising the field, the current through the conductors thereby being a substitute for the superconductive shield. The conductors may be evenly spaced and connected in parallel, their resistances being determined by thickness or composition to provide the desired current, or they may carry equal currents but be differently spaced. A further set or sets of controlled conductors outside the first set may ensure that the first set does not upset the field from the NMR coil. The shield may selectively reflect certain fields while transmitting others and may prevent acoustic vibration e.g. when switching gradient fields. An RF coil arrangement may consist of two orthogonal coils, one coil within the other for use as a transmit/receive set or as a double resonance transmitter; a shield between the coils is in series with, and formed from the same winding as, the inner coil. (author)

  7. Cost model for geothermal wells applied to the Cerro Prieto geothermal field case, BC Abstract; Modelo de costeo de pozos geotermicos aplicado para el caso del campo geotermico de Cerro Prieto, BC

    Energy Technology Data Exchange (ETDEWEB)

    Vaca Serrano, Jaime M.E [Comision Federal de Electricidad, Gerencia de Proyectos Geotermoelectricos, Morelia, Michoacan (Mexico)]. E-mail: jaime.vaca@cfe.gob.mx

    2008-01-15

    A project for drilling geothermal wells to produce electrical energy can be defined as a sequence of plans to get steam or geothermal fluids to satisfy a previously known demand, and, under the best possible conditions, to obtain payment. This paper presents a cost model for nine wells drilled at the Cerro Prieto geothermal field in 2005 and 2006 to supply steam to the power plants operating in the field. The cost model is based on the well cost, the initial steam production, the annual decline of steam, the drilling schedule and the break-even point for each well. The model shows the cost of steam by the ton and the sale price needed to determine the discount rate and the investment return time. [Spanish] Un proyecto de perforacion de pozos geotermicos puede definirse como una secuencia o sucesion de planes para obtener vapor o fluidos geotermicos destinados a satisfacer una demanda previamente determinada, que se emplearan principalmente para generar energia electrica, bajo las mejores condiciones para obtener un pago. Este trabajo presenta un modelo de costeo para nueve pozos en el campo geotermico de Cerro Prieto, que fueron perforados entre 2005 y 2006 como parte del suministro de vapor para las plantas generadoras que operan en este campo. El modelo de costeo se basa en el costo por pozo, la produccion inicial de vapor, la declinacion anual de vapor, los intereses de las obras de perforacion y el punto de equilibrio para cada pozo. Los resultados permiten conocer el costo de la tonelada de vapor y el precio de venta para determinar la tasa de descuento y el tiempo de retorno de la inversion.

  8. Magnetic fields at Neptune

    International Nuclear Information System (INIS)

    Ness, N.F.; Acuna, M.H.; Burlaga, L.F.; Connerney, J.E.P.; Lepping, R.P.; Neubauer, F.M.

    1989-01-01

    The National Aeronautics and Space Administration Goddard Space Flight Center-University of Delaware Bartol Research Institute magnetic field experiment on the Voyager 2 spacecraft discovered a strong and complex intrinsic magnetic field of Neptune and an associated magnetosphere and magnetic tail. A maximum magnetic field of nearly 10,000 nanoteslas (1 nanotesla = 10 -5 gauss) was observed near closest approach, at a distance of 1.18 R N . The planetary magnetic field between 4 and 15 R N can be well represented by an offset tilted magnetic dipole (OTD), displaced from the center of Neptune by the surprisingly large amount of 0.55 R N and inclined by 47 degrees with respect to the rotation axis. Within 4 R N , the magnetic field representation must include localized sources or higher order magnetic multipoles, or both, which are not yet well determined. As the spacecraft exited the magnetosphere, the magnetic tail appeared to be monopolar, and no crossings of an imbedded magnetic field reversal or plasma neutral sheet were observed. The auroral zones are most likely located far from the rotation poles and may have a complicated geometry. The rings and all the known moons of Neptune are imbedded deep inside the magnetosphere, except for Nereid, which is outside when sunward of the planet. The radiation belts will have a complex structure owing to the absorption of energetic particles by the moons and rings of Neptune and losses associated with the significant changes in the diurnally varying magnetosphere configuration. In an astrophysical context, the magnetic field of Neptune, like that of Uranus, may be described as that of an oblique rotator

  9. Magnetic Fields Versus Gravity

    Science.gov (United States)

    Hensley, Kerry

    2018-04-01

    Deep within giant molecular clouds, hidden by dense gas and dust, stars form. Unprecedented data from the Atacama Large Millimeter/submillimeter Array (ALMA) reveal the intricate magnetic structureswoven throughout one of the most massive star-forming regions in the Milky Way.How Stars Are BornThe Horsehead Nebulasdense column of gas and dust is opaque to visible light, but this infrared image reveals the young stars hidden in the dust. [NASA/ESA/Hubble Heritage Team]Simple theory dictates that when a dense clump of molecular gas becomes massive enough that its self-gravity overwhelms the thermal pressure of the cloud, the gas collapses and forms a star. In reality, however, star formation is more complicated than a simple give and take between gravity and pressure. Thedusty molecular gas in stellar nurseries is permeated with magnetic fields, which are thought to impede the inward pull of gravity and slow the rate of star formation.How can we learn about the magnetic fields of distant objects? One way is by measuring dust polarization. An elongated dust grain will tend to align itself with its short axis parallel to the direction of the magnetic field. This systematic alignment of the dust grains along the magnetic field lines polarizes the dust grains emission perpendicular to the local magnetic field. This allows us to infer the direction of the magnetic field from the direction of polarization.Magnetic field orientations for protostars e2 and e8 derived from Submillimeter Array observations (panels a through c) and ALMA observations (panels d and e). Click to enlarge. [Adapted from Koch et al. 2018]Tracing Magnetic FieldsPatrick Koch (Academia Sinica, Taiwan) and collaborators used high-sensitivity ALMA observations of dust polarization to learn more about the magnetic field morphology of Milky Way star-forming region W51. W51 is one of the largest star-forming regions in our galaxy, home to high-mass protostars e2, e8, and North.The ALMA observations reveal

  10. Comparação entre dois métodos de posicionamento para realização do raio X e sua repercussão na avaliação da cifose torácica utilizando o método de Cobb e no equilíbrio sagital Comparación entre dos métodos de posicionamiento para la realización del rayo X y sus efectos sobre evaluación de la cifosis torácica usando el método de Cobb y el sagital equilibrio Comparison between two positioning methods for X-ray and its impact on the evaluation of thoracic kyphosis by Cobb's method and sagittal balance

    Directory of Open Access Journals (Sweden)

    Carlos Henrique Maçaneiro

    2010-12-01

    Full Text Available INTRODUÇÃO: o tratamento da cifose torácica é baseado na aferição da magnitude da curva baseada em mensurações radiográficas, e proporcionar o correto equilíbrio sagital pela correção cirúrgica de uma gibosidade é de importância fundamental. OBJETIVO: análise radiográfica prospectiva do efeito da variação da posição dos braços sobre a aferição da cifose torácica e do equilíbrio sagital entre pacientes com idades pré-estabelecidas. MÉTODOS: foram realizadas radiografias na posição lateral da coluna vertebral utilizando-se dois métodos posicionais: posição 1, em que o paciente permanecia de pé, com os joelhos juntos, pés alinhados com os ombros, cabeça reta direcionada para a frente, braços estendidos a 90º em relação ao tronco, mantendo os membros superiores estendidos e paralelos ao chão; uma segunda radiografia foi obtida com o paciente de pé, com os joelhos juntos, pés alinhados com os ombros, cabeça reta direcionada para a frente, com os cotovelos fletidos e os dedos repousando sobre a fossa supraclavicular bilateralmente. Os braços devem formar um ângulo de aproximadamente 45º com o corpo. Foram mensurados os ângulos de Cobb e o equilíbrio sagital nas duas radiografias. RESULTADOS: não houve correlação entre a posição dos braços, os valores angulares de Cobb e o equilíbrio sagital. CONCLUSÃO: em nosso trabalho, observamos que a posição dos braços (90º versus 45º, não interfere estatisticamente no valor da cifose torácica e na variação do equilíbrio sagital.INTRODUCCIÓN: el tratamiento de la cifosis torácica se basa en la medición de la magnitud de la curva a partir de mediciones radiológicas, y proporcionar el equilibrio adecuado para la corrección quirúrgica de la deformidad de la columna sagital es de una importancia fundamental. OBJETIVO: un análisis prospectivo radiográfico del efecto de la variación en la posición de los brazos en la medición de la cifosis tor

  11. Theoretical physics. Field theory

    International Nuclear Information System (INIS)

    Landau, L.; Lifchitz, E.

    2004-01-01

    This book is the fifth French edition of the famous course written by Landau/Lifchitz and devoted to both the theory of electromagnetic fields and the gravity theory. The talk of the theory of electromagnetic fields is based on special relativity and relates to only the electrodynamics in vacuum and that of pointwise electric charges. On the basis of the fundamental notions of the principle of relativity and of relativistic mechanics, and by using variational principles, the authors develop the fundamental equations of the electromagnetic field, the wave equation and the processes of emission and propagation of light. The theory of gravitational fields, i.e. the general theory of relativity, is exposed in the last five chapters. The fundamentals of the tensor calculus and all that is related to it are progressively introduced just when needed (electromagnetic field tensor, energy-impulse tensor, or curve tensor...). The worldwide reputation of this book is generally allotted to clearness, to the simplicity and the rigorous logic of the demonstrations. (A.C.)

  12. Field error lottery

    Energy Technology Data Exchange (ETDEWEB)

    Elliott, C.J.; McVey, B. (Los Alamos National Lab., NM (USA)); Quimby, D.C. (Spectra Technology, Inc., Bellevue, WA (USA))

    1990-01-01

    The level of field errors in an FEL is an important determinant of its performance. We have computed 3D performance of a large laser subsystem subjected to field errors of various types. These calculations have been guided by simple models such as SWOOP. The technique of choice is utilization of the FELEX free electron laser code that now possesses extensive engineering capabilities. Modeling includes the ability to establish tolerances of various types: fast and slow scale field bowing, field error level, beam position monitor error level, gap errors, defocusing errors, energy slew, displacement and pointing errors. Many effects of these errors on relative gain and relative power extraction are displayed and are the essential elements of determining an error budget. The random errors also depend on the particular random number seed used in the calculation. The simultaneous display of the performance versus error level of cases with multiple seeds illustrates the variations attributable to stochasticity of this model. All these errors are evaluated numerically for comprehensive engineering of the system. In particular, gap errors are found to place requirements beyond mechanical tolerances of {plus minus}25{mu}m, and amelioration of these may occur by a procedure utilizing direct measurement of the magnetic fields at assembly time. 4 refs., 12 figs.

  13. Multi-valued fields

    CERN Document Server

    Ershov, Yuri L

    2001-01-01

    For more than 30 years, the author has studied the model-theoretic aspects of the theory of valued fields and multi-valued fields. Many of the key results included in this book were obtained by the author whilst preparing the manuscript. Thus the unique overview of the theory, as developed in the book, has been previously unavailable. The book deals with the theory of valued fields and mutli-valued fields. The theory of Prüfer rings is discussed from the `geometric' point of view. The author shows that by introducing the Zariski topology on families of valuation rings, it is possible to distinguish two important subfamilies of Prüfer rings that correspond to Boolean and near Boolean families of valuation rings. Also, algebraic and model-theoretic properties of multi-valued fields with near Boolean families of valuation rings satisfying the local-global principle are studied. It is important that this principle is elementary, i.e., it can be expressed in the language of predicate calculus. The most important...

  14. Electromagnetic fields and cancer

    International Nuclear Information System (INIS)

    Singh, Neeta; Mathur, R.; Behari, J.

    1997-01-01

    Several studies in recent years have raised the possibility that exposure to electromagnetic fields (EMFs) may be hazardous to human health, in particular by promotion or initiation of cancer. Recent reports have indicated increased cancer risk from industrial and domestic exposure to environmental ELF fields and to RF fields that are amplitude modulated at ELF. EMF fields have been reported to affect biological systems in various ways, affecting changes in the morphology and or functional behavior of cells, which have been observed in a variety of tissues. Although the mechanism of interaction of EMFs with living cells are not known, it has been proposed that they have multiple effects and can affect cell signalling, including modification of plasma membrane permeability and ion transport. Our findings suggest that EMFs can affect post translational modification of proteins such as poly ADP-ribosylation by epigenetic mechanism and that the effect of EMFs are highly specific regarding both the cell type and the frequency and amplification of the applied field. (author)

  15. String field theory

    International Nuclear Information System (INIS)

    Kaku, M.

    1987-01-01

    In this article, the authors summarize the rapid progress in constructing string field theory actions, such as the development of the covariant BRST theory. They also present the newer geometric formulation of string field theory, from which the BRST theory and the older light cone theory can be derived from first principles. This geometric formulation allows us to derive the complete field theory of strings from two geometric principles, in the same way that general relativity and Yang-Mills theory can be derived from two principles based on global and local symmetry. The geometric formalism therefore reduces string field theory to a problem of finding an invariant under a new local gauge group they call the universal string group (USG). Thus, string field theory is the gauge theory of the universal string group in much the same way that Yang-Mills theory is the gauge theory of SU(N). The geometric formulation places superstring theory on the same rigorous group theoretical level as general relativity and gauge theory

  16. Cosmic magnetic fields

    CERN Document Server

    Kronberg, Philipp P

    2016-01-01

    Magnetic fields are important in the Universe and their effects contain the key to many astrophysical phenomena that are otherwise impossible to understand. This book presents an up-to-date overview of this fast-growing topic and its interconnections to plasma processes, astroparticle physics, high energy astrophysics, and cosmic evolution. The phenomenology and impact of magnetic fields are described in diverse astrophysical contexts within the Universe, from galaxies to the filaments and voids of the intergalactic medium, and out to the largest redshifts. The presentation of mathematical formulae is accessible and is designed to add insight into the broad range of topics discussed. Written for graduate students and researchers in astrophysics and related disciplines, this volume will inspire readers to devise new ways of thinking about magnetic fields in space on galaxy scales and beyond.

  17. Nonlocal quantum field theory

    International Nuclear Information System (INIS)

    Efimov, G.V.

    1976-01-01

    The basic ideas for creating the theory of nonlocal interactions of a scalar one-component field are presented. Lagrangian describing a non-interacting field is the ordinary one so that non-interacting particles are described by standard methods of the Fock space. Form factors introduced have been chosen from a class of analytic functionals and quantized. Conditions of microcausality have been considered in detail. The convergence of all integrals corresponding to the arbitrary Feynman diagrams in spinor electrodynamics is guaranteed in the frame of the rules formulated. It is noted in conclusion that the spinor electrodynamics with nonlocal interaction contains no ultraviolet divergencies and satisfies all the requirements of the quantum field theory; in this sense it is mathematically more consistent than its local version

  18. Collinear wake field acceleration

    International Nuclear Information System (INIS)

    Bane, K.L.F.; Chen, P.; Wilson, P.B.

    1985-04-01

    In the Voss-Weiland scheme of wake field acceleration a high current, ring-shaped driving bunch is used to accelerate a low current beam following along on axis. In such a structure, the transformer ratio, i.e., the ratio of maximum voltage that can be gained by the on-axis beam and the voltage lost by the driving beam, can be large. In contrast, it has been observed that for an arrangement in which driving and driven bunches follow the same path, and where the current distribution of both bunches is gaussian, the transformer ratio is not normally greater than two. This paper explores some of the possibilities and limitations of a collinear acceleration scheme. In addition to its application to wake field acceleration in structures, this study is also of interest for the understanding of the plasma wake field accelerator. 11 refs., 4 figs

  19. Gyrokinetic field theory

    International Nuclear Information System (INIS)

    Sugama, H.

    1999-08-01

    The Lagrangian formulation of the gyrokinetic theory is generalized in order to describe the particles' dynamics as well as the self-consistent behavior of the electromagnetic fields. The gyrokinetic equation for the particle distribution function and the gyrokinetic Maxwell's equations for the electromagnetic fields are both derived from the variational principle for the Lagrangian consisting of the parts of particles, fields, and their interaction. In this generalized Lagrangian formulation, the energy conservation property for the total nonlinear gyrokinetic system of equations is directly shown from the Noether's theorem. This formulation can be utilized in order to derive the nonlinear gyrokinetic system of equations and the rigorously conserved total energy for fluctuations with arbitrary frequency. (author)

  20. Electromagnetic fields and life

    CERN Document Server

    Presman, A S

    1970-01-01

    A broad region of the electromagnetic spectrum long assumed to have no influence on living systems under natural conditions has been critically re-examined over the past decade. This spectral region extends from the superhigh radio frequencies, through de­ creasing frequencies, to and including essentially static electric and magnetic fields. The author of this monograph, A. S. Presman, has reviewed not only the extensive Russian literatur!;"l, but also al­l most equally comprehensively the non-Russian literature, dealing with biological influences of these fields. Treated also is literature shedding some light on possible theoretical foundations for these phenomena. A substantial, rapidly increasing number of studies in many laboratories and countries has now clearly established bio­ logical influences which are independent of the theoretically predictable, simple thermal effects. Indeed many of the effects are produced by field strengths very close to those within the natural environment. The author has,...

  1. Electromagnetic fields and waves

    CERN Document Server

    Iskander, Magdy F

    2013-01-01

    The latest edition of Electromagnetic Fields and Waves retains an authoritative, balanced approach, in-depth coverage, extensive analysis, and use of computational techniques to provide a complete understanding of electromagnetic—important to all electrical engineering students. An essential feature of this innovative text is the early introduction of Maxwell's equations, together with the quantifying experimental observations made by the pioneers who discovered electromagnetics. This approach directly links the mathematical relations in Maxwell's equations to real experiments and facilitates a fundamental understanding of wave propagation and use in modern practical applications, especially in today's wireless world. New and expanded topics include the conceptual relationship between Coulomb's law and Gauss's law for calculating electric fields, the relationship between Biot-Savart's and Ampere's laws and their use in calculating magnetic fields from current sources, the development of Faraday's law from e...

  2. Supersymmetric gauge field theories

    International Nuclear Information System (INIS)

    Slavnov, A.A.

    1976-01-01

    The paper is dealing with the role of supersymmetric gauge theories in the quantum field theory. Methods of manipulating the theories as well as possibilities of their application in elementary particle physics are presented. In particular, the necessity is explained of a theory in which there is symmetry between Fermi and Bose fields, in other words, of the supersymmetric gauge theory for construction of a scheme for the Higgs particle connecting parameters of scalar mesons with those of the rest fields. The mechanism of supersymmetry breaking is discussed which makes it possible to remain the symmetric procedure of renormalization intact. The above mechanism of spontaneous symmetry breaking is applied to demonstrate possibilities of constructing models of weak and electromagnetic interactions which would be acceptable from the point of view of experiments. It is noted that the supersymmetric gauge theories represent a natural technique for description of vector-like models

  3. Reversed field pinch experiments

    International Nuclear Information System (INIS)

    Roberston, S.

    1991-05-01

    The Reversatron RFP is usually operated with toroidal field windings which are a continuous helix of 144 turns. These windings produce a poloidal current which is uniform around the torus. The distribution of current is fixed by the geometry so that the applied field has only an m = 0, n = 0 component. The windings cannot act to stabilize an m = 0 mode with |n| > 0 or any m = 1 mode because these modes will excite no current in the windings. It has recently been suggested that parallel connected field coils might act as a shell by forcing the flux within each winding to be the same. Coils connected in parallel must have the same voltage at their terminals and thus must enclose the same volt-seconds or flux. Data from ZT-40 show that the discharges are more quiescent when parallel or series-parallel connected windings are used

  4. Energy of the field for the field

    International Nuclear Information System (INIS)

    2001-01-01

    Considering the problems that are presented in the field related with the lack of available energy is presented, the Biogas like energy alternative. This is a resulting product of the fermentation anaerobic (without air) of the organic residuals under appropriate conditions of humidity. It is a mixture of gases in which they prevail: Methane (CH 4 ) in a 55 to 70 percent, Dioxide of Carbon (CO 2 ) in a 28 to 43 percent and others as the hydro sulphide by 2 percent. The composition of the biogas depends of: the quality of the used material, of the biodigestor type, of the ambient temperature, of the adopted time of retention. Some of the advantages of the use of this alternative are: better sanitary conditions in the rural means. Decrease in the consumption of inorganic fertilizers. Increase of the agricultural productivity with the employment of the Bio fertilizing (20/25 bigger percent) in comparison with the fresh manure; conservation of natural resources as fuels, fossils and firewood; energy production in the own local consumption. Perfect ecological solution for the obtaining of renewable energy and bio fertilizing

  5. Microcanonical quantum field theory

    International Nuclear Information System (INIS)

    Strominger, A.

    1983-01-01

    Euclidean quantum field theory is equivalent to the equilibrium statistical mechanics of classical fields in 4+1 dimensions at temperature h. It is well known in statistical mechanics that the theory of systems at fixed temperature is embedded within the more general and fundamental theory of systems at fixed energy. We therefore develop, in precise analogy, a fixed action (macrocanonical) formulation of quantum field theory. For the case of ordinary renormalizable field theories, we show (with one exception) that the microcanonical is entirely equivalent to the canonical formulation. That is, for some particular fixed value of the total action, the Green's functions of the microcanonical theory are equal, in the bulk limit, to those of the canonical theory. The microcanonical perturbation expansion is developed in some detail for lambdaphi 4 . The particular value of the action for which the two formulations are equivalent can be calculated to all orders in perturbation theory. We prove, using Lehmann's Theorem, that this value is one-half Planck unit per degree of freedom, if fermionic degrees of freedom are counted negatively. This is the 4+1 dimensional analog of the equipartition theorem. The one exception to this is supersymmetric theories. A microcanonical formulation exists if and only if supersymmetry is broken. In statistical mechanics and in field theory there are systems for which the canonical description is pathological, but the microcanonical is not. An example of such a field theory is found in one dimension. A semiclassical expansion of the microcanonical theory is well defined, while an expansion of the canonical theory is hoplessly divergent

  6. Tripolar electric field Structure in guide field magnetic reconnection

    Science.gov (United States)

    Fu, Song; Huang, Shiyong; Zhou, Meng; Ni, Binbin; Deng, Xiaohua

    2018-03-01

    It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

  7. Tripolar electric field Structure in guide field magnetic reconnection

    Directory of Open Access Journals (Sweden)

    S. Fu

    2018-03-01

    Full Text Available It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection. In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg. Once the amplitude of a guide field exceeds 0.3 times the asymptotic magnetic field B0, the traditional bipolar Hall electric field is clearly replaced by a tripolar electric field, which consists of a newly emerged electric field and the bipolar Hall electric field. The newly emerged electric field is a convective electric field about one ion inertial length away from the neutral sheet. It arises from the disappearance of the Hall electric field due to the substantial modification of the magnetic field and electric current by the imposed guide field. The peak magnitude of this new electric field increases linearly with the increment of guide field strength. Possible applications of these results to space observations are also discussed.

  8. Quaternionic quantum field theory

    International Nuclear Information System (INIS)

    Adler, S.L.

    1986-01-01

    In this paper the author describes a new kind of quantum mechanics or quantum field theory based on quaternions. Quaternionic quantum mechanics has a Schrodinger equation, a Dirac transformation theory, and a functional integral. Quaternionic quantum mechanics does not seem to have (except in the complex quantum mechanics specialization): A correspondence principle, and beyond this a commuting tensor product, asymptotic states, an S-matrix, a canonical formalism, coherent states or a Euclidean continuation. A new kind of quantum mechanics exists. There are many interesting formal questions to study, which should enable one to decide whether quaternionic quantum field theory is relevant for particle physics

  9. Quantum field theory

    CERN Document Server

    Mandl, Franz

    2010-01-01

    Following on from the successful first (1984) and revised (1993) editions, this extended and revised text is designed as a short and simple introduction to quantum field theory for final year physics students and for postgraduate students beginning research in theoretical and experimental particle physics. The three main objectives of the book are to: Explain the basic physics and formalism of quantum field theory To make the reader proficient in theory calculations using Feynman diagrams To introduce the reader to gauge theories, which play a central role in elementary particle physic

  10. Field studies courses open

    Science.gov (United States)

    Fourteen month-long courses combining applied academics with training in field research methodology are being offered this summer by the School for Field Studies. The courses, held in eight countries during May, June, July, and August, provide unique opportunities for participants to work as a team under primitive conditions.‘Our courses bind together the academic challenge of the research problem, the physical challenge of the site itself, and the interpersonal challenge of the expedition team in a dynamic way so that both cognitive and affective learning are accelerated,’ according to Jim Elder, the school's director.

  11. WORKSHOP: Thermal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1989-04-15

    The early history of the Universe is a crucial testing ground for theories of elementary particles. Speculative ideas about the constituents of matter and their interactions are reinforced if they are consistent with what we suppose happened near the beginning of time and discarded if they are not. The cosmological consequences of these theories are usually deduced using a general statistical approach called thermal field theory. Thus, 75 physicists from thirteen countries met in Cleveland, Ohio, last October for the first 'Workshop on Thermal Field Theories and their Applications'.

  12. Gauge field theories

    International Nuclear Information System (INIS)

    Pokorski, S.

    1987-01-01

    Quantum field theory forms the present theoretical framework for the understanding of the fundamental interactions of particle physics. This book examines gauge theories and their symmetries with an emphasis on their physical and technical aspects. The author discusses field-theoretical techniques and encourages the reader to perform many of the calculations presented. This book includes a brief introduction to perturbation theory, the renormalization programme, and the use of the renormalization group equation. Several topics of current research interest are covered, including chiral symmetry and its breaking, anomalies, and low energy effective lagrangians and some basics of supersymmetry

  13. Finite temperature field theory

    CERN Document Server

    Das, Ashok

    1997-01-01

    This book discusses all three formalisms used in the study of finite temperature field theory, namely the imaginary time formalism, the closed time formalism and thermofield dynamics. Applications of the formalisms are worked out in detail. Gauge field theories and symmetry restoration at finite temperature are among the practical examples discussed in depth. The question of gauge dependence of the effective potential and the Nielsen identities are explained. The nonrestoration of some symmetries at high temperature (such as supersymmetry) and theories on nonsimply connected space-times are al

  14. Interpolating string field theories

    International Nuclear Information System (INIS)

    Zwiebach, B.

    1992-01-01

    This paper reports that a minimal area problem imposing different length conditions on open and closed curves is shown to define a one-parameter family of covariant open-closed quantum string field theories. These interpolate from a recently proposed factorizable open-closed theory up to an extended version of Witten's open string field theory capable of incorporating on shell closed strings. The string diagrams of the latter define a new decomposition of the moduli spaces of Riemann surfaces with punctures and boundaries based on quadratic differentials with both first order and second order poles

  15. Gela offshore field

    Energy Technology Data Exchange (ETDEWEB)

    Pagliughi, G

    1965-06-01

    The field of Gela, off the southern shore of Sicily, is the only producing offshore field in the Mediterranean. It produces from Triassic dolimite limestones of 434-m thickness, water level at -3517 m. It is a water-drive reservoir producing 10/sup 0/F API oil and has 79 wells, some of them on shore. Most offshore wells are directional wells from shore; there are also 2 fixed platforms and a special mobile platform. The wells are on pump (stroke, 72 in.; capacity 200 tons per day). The crude goes directly to a combination refinery-petrochemical complex at Gela.

  16. DSM-5 field survey

    DEFF Research Database (Denmark)

    Lochner, Christine; Grant, Jon E; Odlaug, Brian Lawrence

    2012-01-01

    Pathologic skin picking (skin picking disorder [SPD]) is a prevalent and disabling condition, which has received increasing study. It is timely to consider including SPD in DSM-5. The aim of this field survey was to investigate possible diagnostic criteria for SPD.......Pathologic skin picking (skin picking disorder [SPD]) is a prevalent and disabling condition, which has received increasing study. It is timely to consider including SPD in DSM-5. The aim of this field survey was to investigate possible diagnostic criteria for SPD....

  17. Finite quantum field theories

    International Nuclear Information System (INIS)

    Lucha, W.; Neufeld, H.

    1986-01-01

    We investigate the relation between finiteness of a four-dimensional quantum field theory and global supersymmetry. To this end we consider the most general quantum field theory and analyse the finiteness conditions resulting from the requirement of the absence of divergent contributions to the renormalizations of the parameters of the theory. In addition to the gauge bosons, both fermions and scalar bosons turn out to be a necessary ingredient in a non-trivial finite gauge theory. In all cases discussed, the supersymmetric theory restricted by two well-known constraints on the dimensionless couplings proves to be the unique solution of the finiteness conditions. (Author)

  18. On vector fields having properties of Reeb fields

    OpenAIRE

    Hajduk, Boguslaw; Walczak, Rafal

    2011-01-01

    We study constructions of vector fields with properties which are characteristic to Reeb vector fields of contact forms. In particular, we prove that all closed oriented odd-dimensional manifold have geodesible vector fields.

  19. Electromagnetic fields and their impacts

    Science.gov (United States)

    Prša, M. A.; Kasaš-Lažetić, K. K.

    2018-01-01

    The main goal of this paper is to briefly recall some different electromagnetic field definitions, some macroscopic sources of electromagnetic fields, electromagnetic fields classification regarding time dependences, and the ways of field determination in concrete cases. After that, all the mechanisms of interaction between electromagnetic field and substance, on atomic level, are described in details. Interaction between substance and electric field is investigated separately from the substance and magnetic field interaction. It is demonstrated that, in all cases of the unique electromagnetic field, total interaction can be treated as a superposition of two separated interactions. Finally, the main electromagnetic fields surrounding us is cited and discussed.

  20. Tripolar electric field Structure in guide field magnetic reconnection

    OpenAIRE

    S. Fu; S. Huang; M. Zhou; B. Ni; X. Deng

    2018-01-01

    It has been shown that the guide field substantially modifies the structure of the reconnection layer. For instance, the Hall magnetic and electric fields are distorted in guide field reconnection compared to reconnection without guide fields (i.e., anti-parallel reconnection). In this paper, we performed 2.5-D electromagnetic full particle simulation to study the electric field structures in magnetic reconnection under different initial guide fields (Bg). Once the amplit...

  1. Electromagnetic Fields and Cancer

    Science.gov (United States)

    ... and magnetic fields (1 Hz to 100 kHz) . Health Physics 2010; 99(6):818-36. doi: 10.1097/ ... and health: review of current status of research. Health Physics 2013; 105(6):561-75. [PubMed Abstract] AGNIR. ...

  2. Ultrasonogram in obstetric field

    International Nuclear Information System (INIS)

    Joo, K. B.; Song, C. H.; Lee, H. B.

    1980-01-01

    The clinical evaluation of 535 cases of sonogram from Mar. 1, 1979 to Oct. 30, 1979 in obstetric field at Department of Radiology and Ob. and Gy. Eul-Ji General Hospital. We present these cases: normal pregnancy, missed abortion, twin pregnancy, hydatidiform mole and ectopic pregnancy, with brief review of literature.

  3. Linking lab and field

    International Nuclear Information System (INIS)

    Cronje, P.B.

    1988-01-01

    The multitude of different supplements recommended for animals grazing natural pastures, which testifies to the need for a metabolic basis for supplementary feeding practices. The first approach to this problem was to simulate different feeding conditions in the laboratory, where the metabolic responses of body tissues to changes in the supply of purified nutrients could be studied using radioisotope techniques. The second step was to link these fundamental studies to field conditions. The results of these studies suggest that the efficiency of feed conversion and growth rates of ruminants grazing winter pastures in the highveld region of South Africa could be substantially improved by strategic supplementation with glucose precursors. Acetate clearance rate represents a valuable link in the process of applying information obtained from controlled laboratory experiments to field conditions. As this technique is inexpensive, quick and simple to carry out, it is ideally suited to application under field conditions where the use of isotopes is impractical. By providing a link with field conditions, it greatly extended the scope and practical application of isotope tracer techniques

  4. Warp Field Mechanics 101

    Science.gov (United States)

    White, Harold

    2011-01-01

    This paper will begin with a short review of the Alcubierre warp drive metric and describes how the phenomenon might work based on the original paper. The canonical form of the metric was developed and published in [6] which provided key insight into the field potential and boost for the field which remedied a critical paradox in the original Alcubierre concept of operations. A modified concept of operations based on the canonical form of the metric that remedies the paradox is presented and discussed. The idea of a warp drive in higher dimensional space-time (manifold) will then be briefly considered by comparing the null-like geodesics of the Alcubierre metric to the Chung-Freese metric to illustrate the mathematical role of hyperspace coordinates. The net effect of using a warp drive technology coupled with conventional propulsion systems on an exploration mission will be discussed using the nomenclature of early mission planning. Finally, an overview of the warp field interferometer test bed being implemented in the Advanced Propulsion Physics Laboratory: Eagleworks (APPL:E) at the Johnson Space Center will be detailed. While warp field mechanics has not had a Chicago Pile moment, the tools necessary to detect a modest instance of the phenomenon are near at hand.

  5. Parafermionic conformal field theory

    International Nuclear Information System (INIS)

    Kurak, V.

    1989-09-01

    Conformal parafermionic field theories are reviewed with emphasis on the computation of their OPE estructure constants. It is presented a simple computational of these for the Z(N) parafermions, unveilling their Lie algebra content. (A.C.A.S.) [pt

  6. What Are Electromagnetic Fields?

    Science.gov (United States)

    ... field causes a compass needle to orient in a North-South direction and is used by birds and fish for navigation. Human-made sources of ... and form the basis of telecommunications as well as radio and television ... In microwaves ovens, we use them to quickly heat food. At ...

  7. Superspace conformal field theory

    Energy Technology Data Exchange (ETDEWEB)

    Quella, Thomas [Koeln Univ. (Germany). Inst. fuer Theoretische Physik; Schomerus, Volker [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2013-07-15

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  8. Superspace conformal field theory

    International Nuclear Information System (INIS)

    Quella, Thomas

    2013-07-01

    Conformal sigma models and WZW models on coset superspaces provide important examples of logarithmic conformal field theories. They possess many applications to problems in string and condensed matter theory. We review recent results and developments, including the general construction of WZW models on type I supergroups, the classification of conformal sigma models and their embedding into string theory.

  9. Field Guide to Radiometry

    CERN Document Server

    Grant, Barbara

    2011-01-01

    Written from a systems engineering perspective, this SPIE Field Guide covers topics in optical radiation propagation, material properties, sources, detectors, system components, measurement, calibration, and photometry. The book's organization and extensive collection of diagrams, tables, and graphs will enable the reader to efficiently identify and apply relevant information to radiometric problems arising amid the demands of today's fast-paced technical environment.

  10. Field ion microscopy

    International Nuclear Information System (INIS)

    Ramanathan, D.

    1975-01-01

    The basic features of the Field-Ion Microscope (FIM) and the theory of image formation are explained. Design parameters of the FIM, factors limiting its resolution, interpretation of the image, etc are briefly outlined. Relative merits of the various imaging gases and the applications of the FIM are also covered. (K.B.)

  11. Planetary plasmas and fields

    International Nuclear Information System (INIS)

    Roederer, J.G.

    1976-01-01

    The magnetospheres of earth, Jupiter, and Mercury are discussed. The main features and physical processes characteristic of the quiet time earth magnetosphere are examined. Jupiter's larger and more distant magnetosphere is compared with the earth's and recent findings are reviewed. The plasma and field environment of Mercury is also discussed and similarities with the earth's magnetosphere are noted

  12. Reflections on the Field.

    Science.gov (United States)

    Kauffman, James M.

    2003-01-01

    Reflections on the field of special education offer six ideas: (1) the value of science; (2) the continuing value of separate and special education for some students; (3) the continuing importance of prevention; (4) the importance of academic instruction; (5) the importance of social justice for the poor; and (6) a renewed emphasis on human…

  13. Axiomatic conformal field theory

    International Nuclear Information System (INIS)

    Gaberdiel, M.R.; Goddard, P.

    2000-01-01

    A new rigourous approach to conformal field theory is presented. The basic objects are families of complex-valued amplitudes, which define a meromorphic conformal field theory (or chiral algebra) and which lead naturally to the definition of topological vector spaces, between which vertex operators act as continuous operators. In fact, in order to develop the theory, Moebius invariance rather than full conformal invariance is required but it is shown that every Moebius theory can be extended to a conformal theory by the construction of a Virasoro field. In this approach, a representation of a conformal field theory is naturally defined in terms of a family of amplitudes with appropriate analytic properties. It is shown that these amplitudes can also be derived from a suitable collection of states in the meromorphic theory. Zhu's algebra then appears naturally as the algebra of conditions which states defining highest weight representations must satisfy. The relationship of the representations of Zhu's algebra to the classification of highest weight representations is explained. (orig.)

  14. NPOESS Field Terminal Updates

    Science.gov (United States)

    Heckmann, G.; Route, G.

    2009-12-01

    The National Oceanic and Atmospheric Administration (NOAA), Department of Defense (DoD), and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation weather and environmental satellite system; the National Polar-orbiting Operational Environmental Satellite System (NPOESS). NPOESS replaces the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the Defense Meteorological Satellite Program (DMSP) managed by the DoD. The NPOESS satellites carry a suite of sensors that collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The ground data processing segment for NPOESS is the Interface Data Processing Segment (IDPS), developed by Raytheon Intelligence and Information Systems. The IDPS processes NPOESS satellite data to provide environmental data products (aka, Environmental Data Records or EDRs) to NOAA and DoD processing centers operated by the United States government. The IDPS will process EDRs beginning with the NPOESS Preparatory Project (NPP) and continuing through the lifetime of the NPOESS system. IDPS also provides the software and requirements for the Field Terminal Segment (FTS). NPOESS provides support to deployed field terminals by providing mission data in the Low Rate and High Rate downlinks (LRD/HRD), mission support data needed to generate EDRs and decryption keys needed to decrypt mission data during Selective data Encryption (SDE). Mission support data consists of globally relevant data, geographically constrained data, and two line element sets. NPOESS provides these mission support data via the Internet accessible Mission Support Data Server and HRD/LRD downlinks. This presentation will illustrate and describe the NPOESS capabilities in support of Field Terminal users. This discussion will include the mission support data available to Field Terminal users, content of the direct broadcast HRD and LRD

  15. Study with radio-sulphur of the kinetics of the process SO{sub 2} + 0.5 O{sub 2} {r_reversible} SO{sub 3} in a state of chemical equilibrium on a platinum catalyst; Etude, a l'aide du soufre radioactif, de la cinetique de la reaction SO{sub 2} + 0,5 O{sub 2} {r_reversible} SO{sub 3} en equilibre chimique, en presence d'un catalyseur de platine; Issledovanie pri pomoshchi radioaktivnoj sery kinetiki protsessa SO{sub 2} + 0,5 O{sub 2} {r_reversible} SO{sub 3}, nakhodyashchegosya v sostoyanii khimicheskogo ravnovesiya, na platinovom katalizatore; Estudio, con ayuda de azufre radiactivo, de la cinetica de la reaccion SO{sub 2} + 0,5 O{sub 2} {r_reversible} SO{sub 3} en equilibrio quimico en presencia de un catalizador de platino

    Energy Technology Data Exchange (ETDEWEB)

    Rojter, V A; Stukanovskaya, N A; Kornejchuk, G P

    1962-03-15

    The authors describe an attempt to use radioisotopes in the study of the kinetics of heterogeneous catalytic processes in a state of equilibrium. The investigation was carried out by the circulation method. After establishment of equilibrium, a small amount of S{sup 35}O{sub 2} was introduced into the system as a tracer and its conversion rate into S{sup 35}O{sub 3} was measured. From that rate the speed of the direct and inverse processes of oxidation of SO{sub 2} on the catalyst was calculated. Possible sequence patterns for the process are suggested and discussed. (author) [French] Le memoire expose un essai d'application des radioisotopes a l'etude de la cinetique des reactions catalytiques heterogenes en equilibre chimique. Les recherches ont ete effectuees par la methode a circulation. Apres etablissement de l'equilibre, on a introduit comme indicateur une petite quantite de {sup 35}SO{sub 2} et mesure la vitesse de sa transformation en {sup 35}SO{sub 3}. En partant de cette vitesse, on a calcule celle du processus d'oxydation directe et inverse du SO{sub 2} sur le catalyseur. Les auteurs proposent et etudient differentes formules selon lesquelles la reaction peut se derouler. (author) [Spanish] Los autores describen un experimento sobre el empleo de radioisotopos en el estudio de la cinetica de procesos cataliticos heterogeneos en estado de equilibrio. La investigacion se llevo a cabo por el metodo de circulacion. Una vez establecido el equilibrio, se introdujo en el sistema una pequena cantidad de {sup 35}SO{sub 2} como trazador y se midio su indice de conversion en {sup 35}SO{sub 3}. De dicho indice se dedujo la velocidad de los procesos directo e inverso de oxidacion del SO{sub 2} en presencia del catalizador. Los autores proponen y examinan diversos tipos posibles de cinetica para el proceso. (author) [Russian] Izlagaetsya opyt primeneniya radioaktivnykh izotopov dlya izucheniya kinetiki geterogennykh kataliticheskikh protsessov, nakhodyashchikhsya v

  16. Gravitational Field Shielding by Scalar Field and Type II Superconductors

    Directory of Open Access Journals (Sweden)

    Zhang B. J.

    2013-01-01

    Full Text Available The gravitational field shielding by scalar field and type II superconductors are theoret- ically investigated. In accord with the well-developed five-dimensional fully covariant Kaluza-Klein theory with a scalar field, which unifies the Einsteinian general relativity and Maxwellian electromagnetic theory, the scalar field cannot only polarize the space as shown previously, but also flatten the space as indicated recently. The polariza- tion of space decreases the electromagnetic field by increasing the equivalent vacuum permittivity constant, while the flattening of space decreases the gravitational field by decreasing the equivalent gravitational constant. In other words, the scalar field can be also employed to shield the gravitational field. A strong scalar field significantly shield the gravitational field by largely decreasing the equivalent gravitational constant. According to the theory of gravitational field shielding by scalar field, the weight loss experimentally detected for a sample near a rotating ceramic disk at very low tempera- ture can be explained as the shielding of the Earth gravitational field by the Ginzburg- Landau scalar field, which is produced by the type II superconductors. The significant shielding of gravitational field by scalar field produced by superconductors may lead to a new spaceflight technology in future.

  17. Evaluate existing radiation fields

    International Nuclear Information System (INIS)

    Aldrich, J.M.; Haggard, D.L.; Endres, G.W.R.; Fix, J.J.

    1981-01-01

    Knowledge of the spectrum of energies for beta, gamma, and neutron radiation experienced in the field is crucial to the proper interpretation of personnel dose. Calibration sources and techniques are determined on the basis of their relationship to field exposure. Selected techniques were used to obtain neutron, photon, and beta energy spectra data at several Hanford locations. Four neutron energy spectra and dose measurement methods were used: (1) multisphere spectrometer system; (2) tissue equivalent proportional counter (TEPC); (3) RASCAL (9'' to 3'' sphere ratios); and (4) helium-3 neutron spectrometer. Gamma spectroscopy was done using standard techniques. A specially designed TLD dosimeter was used to obtain beta spectrum measurements. The design and use of each of these instruments is described in the body of this report. Data collected and analyzed for each of the Hanford locations are included

  18. Algebraic quantum field theory

    International Nuclear Information System (INIS)

    Foroutan, A.

    1996-12-01

    The basic assumption that the complete information relevant for a relativistic, local quantum theory is contained in the net structure of the local observables of this theory results first of all in a concise formulation of the algebraic structure of the superselection theory and an intrinsic formulation of charge composition, charge conjugation and the statistics of an algebraic quantum field theory. In a next step, the locality of massive particles together with their spectral properties are wed for the formulation of a selection criterion which opens the access to the massive, non-abelian quantum gauge theories. The role of the electric charge as a superselection rule results in the introduction of charge classes which in term lead to a set of quantum states with optimum localization properties. Finally, the asymptotic observables of quantum electrodynamics are investigated within the framework of algebraic quantum field theory. (author)

  19. Fisheyes in the field

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper Anders Søren

    2009-01-01

    multiple methods (experience sampling, logging, thinking aloud, and interviews) to describe how the visualization is adopted and used. At the concrete level, our results suggest that the visualization was used as frequently as other tools in the programming environment. We also propose extensions......Information visualizations have been shown useful in numerous laboratory studies, but their adoption and use in real-life tasks are curiously under-researched. We present a field study of ten programmers who work with an editor extended with a fisheye view of source code. The study triangulates...... to the interface and discuss features that were not used in practice. At the methodological level, the study identifies contributions distinct to individual methods and to their combination, and discusses the relative benefits of laboratory studies and field studies for the evaluation of information visualizations....

  20. Field services experiences

    International Nuclear Information System (INIS)

    Colflesh, J.A.; Kruse, P.W.; Merluzzi, R.A.

    1985-01-01

    Combustion Engineering (C-E) is a large diversified manufacturer of products and services for the energy field. At this time, C-E has supplied the nuclear steam supply systems for eleven operating nuclear power plants with two additional units currently undergoing start-up testing. The focus of C-E's commitment in the nuclear power plant services area is the Nuclear Services organization within the Nuclear Power Systems Division. The Nuclear Services organization provides services on a timely cost efficient basis; and dedicates resources to developing new products and services which are truly responsive to the needs of operating power plants world wide. In the paper, C-E's capabilities and experience in the field of nuclear services are described. Highlighted are our capabilities in the areas of transition management services, operating services and engineering services

  1. Quantum field theory

    International Nuclear Information System (INIS)

    Mancini, F.

    1986-01-01

    Theoretical physicists, coming from different countries, working on different areas, gathered at Positano: the Proceedings contain all the lectures delivered as well as contributed papers. Many areas of physics are represented, elementary particles in high energy physics, quantum relativity, quantum geometry, condensed matter physics, statistical mechanics; but all works are concerned with the use of the methods of quantum field theory. The first motivation of the meeting was to pay homage to a great physicist and a great friend; it was also an occasion in which theoretical physicists got together to discuss and to compare results in different fields. The meeting was very intimate; the relaxed atmosphere allowed constructive discussions and contributed to a positive exchange of ideas. (orig.)

  2. Geologic Field Database

    Directory of Open Access Journals (Sweden)

    Katarina Hribernik

    2002-12-01

    Full Text Available The purpose of the paper is to present the field data relational database, which was compiled from data, gathered during thirty years of fieldwork on the Basic Geologic Map of Slovenia in scale1:100.000. The database was created using MS Access software. The MS Access environment ensures its stability and effective operation despite changing, searching, and updating the data. It also enables faster and easier user-friendly access to the field data. Last but not least, in the long-term, with the data transferred into the GISenvironment, it will provide the basis for the sound geologic information system that will satisfy a broad spectrum of geologists’ needs.

  3. Transmission line fields

    International Nuclear Information System (INIS)

    Jeffers, D.E.

    1991-01-01

    There were reports from Russia in the late 1960's and early 1970's that staff in new 500-kV and 750-kV substations were suffering from headaches and other symptoms broadly associated with fatigue. Whilst the Russian results were not confirmed by independent studies, they did serve to stimulate public concern. In 1979 published results of a study of childhood cancer in Denver, Colorado concentrated attention onto the magnetic rather than the electric field. Research programmes in the United Kingdom and elsewhere are briefly described. Although some studies suggest an association between exposure to 50/60 Hz fields and cancer, other studies do not. Having reviewed the evidence, the International Radiation Protection Association, the World Health Organisation, the U.S. Congress Office of Technology Assessment and the U.K. National Radiological Protection Board all consider that the relation is not established. (author)

  4. Quantum Field Theory

    CERN Document Server

    Zeidler, Eberhard

    This is the first volume of a modern introduction to quantum field theory which addresses both mathematicians and physicists ranging from advanced undergraduate students to professional scientists. The book tries to bridge the existing gap between the different languages used by mathematicians and physicists. For students of mathematics it is shown that detailed knowledge of the physical background helps to motivate the mathematical subjects and to discover interesting interrelationships between quite different mathematical topics. For students of physics, fairly advanced mathematics is presented, which is beyond the usual curriculum in physics. It is the author's goal to present the state of the art of realizing Einstein's dream of a unified theory for the four fundamental forces in the universe (gravitational, electromagnetic, strong, and weak interaction). From the reviews: "… Quantum field theory is one of the great intellectual edifices in the history of human thought. … This volume differs from othe...

  5. Particles and quantum fields

    CERN Document Server

    Kleinert, Hagen

    2016-01-01

    This is an introductory book on elementary particles and their interactions. It starts out with many-body Schrödinger theory and second quantization and leads, via its generalization, to relativistic fields of various spins and to gravity. The text begins with the best known quantum field theory so far, the quantum electrodynamics of photon and electrons (QED). It continues by developing the theory of strong interactions between the elementary constituents of matter (quarks). This is possible due to the property called asymptotic freedom. On the way one has to tackle the problem of removing various infinities by renormalization. The divergent sums of infinitely many diagrams are performed with the renormalization group or by variational perturbation theory (VPT). The latter is an outcome of the Feynman-Kleinert variational approach to path integrals discussed in two earlier books of the author, one representing a comprehensive treatise on path integrals, the other dealing with critial phenomena. Unlike ordin...

  6. Wake field acceleration experiments

    International Nuclear Information System (INIS)

    Simpson, J.D.

    1988-01-01

    Where and how will wake field acceleration devices find use for other than, possibly, accelerators for high energy physics? I don't know that this can be responsibly answered at this time. What I can do is describe some recent results from an ongoing experimental program at Argonne which support the idea that wake field techniques and devices are potentially important for future accelerators. Perhaps this will spawn expanded interest and even new ideas for the use of this new technology. The Argonne program, and in particular the Advanced Accelerator Test Facility (AATF), has been reported in several fairly recent papers and reports. But because this is a substantially new audience for the subject, I will include a brief review of the program and the facility before describing experiments. 10 refs., 7 figs

  7. ISR Radial Field Magnet

    CERN Multimedia

    1983-01-01

    There were 37 (normal) + 3 (special) Radial Field magnets in the ISR to adjust vertically the closed orbit. Gap heights and strengths were 200 mm and .12 Tm in the normal magnets, 220 mm and .18 Tm in the special ones. The core length was 430 mm in both types. Due to their small length as compared to the gap heights the end fringe field errors were very important and had to be compensated by suitably shaping the poles. In order to save on cables, as these magnets were located very far from their power supplies, the coils of the normal type magnets were formed by many turns of solid cpper conductor with some interleaved layers of hollow conductor directly cooled by circulating water

  8. Education as "Dilemmatic Field"

    DEFF Research Database (Denmark)

    Tateo, Luca

    2018-01-01

    Psychology of education must discuss a number of relevant ethical, political and societal issues that cannot be simply overlooked as non pertinent to the discipline. For too long educational and developmental psychology have take divergent routes and have not enough dialogued with other fields...... such as pedagogy. I argue that it is first of all necessary to conceptualize the work of schooling, that is educational processes of teaching and learning in specific social contexts, as complex and dilemmatic fields. I discuss contributions from the past and current debate to support my claim that education...... is inherently ambivalent and dilemmatic, while educational psychology is too often normative and prescriptive. As many authors have discussed educational processes as battlefields between political and economic tendencies, we cannot avoid to discuss the relationship of such tendencies and the developmental...

  9. On Scale and Fields

    DEFF Research Database (Denmark)

    Kadish, David

    2017-01-01

    This paper explores thematic parallels between artistic and agricultural practices in the postwar period to establish a link to media art and cultural practices that are currently emerging in urban agriculture. Industrial agriculture has roots in the post-WWII abundance of mechanical and chemical...... equipment and research. These systems are highly mechanically efficient. With minimal physical labour, they extract ever staggering crop yields from ever poorer soils in shifting climatic conditions. However, the fact of mechanical efficiency is used to mask a set of problems with industrial......-scale agricultural systems that range from spreading pests and diseases to poor global distribution of concentrated regional food wealth. That the conversion of vegetatively diverse farmland into monochromatic fields was popularized at the same time as the arrival of colour field paintings like Barnett Newman...

  10. Microcontinuum field theories

    CERN Document Server

    Eringen, A Cemal

    1999-01-01

    Microcontinuum field theories constitute an extension of classical field theories -- of elastic bodies, deformations, electromagnetism, and the like -- to microscopic spaces and short time scales. Material bodies are here viewed as collections of large numbers of deformable particles, much as each volume element of a fluid in statistical mechanics is viewed as consisting of a large number of small particles for which statistical laws are valid. Classical continuum theories are valid when the characteristic length associated with external forces or stimuli is much larger than any internal scale of the body under consideration. When the characteristic lengths are comparable, however, the response of the individual constituents becomes important, for example, in considering the fluid or elastic properties of blood, porous media, polymers, liquid crystals, slurries, and composite materials. This volume is concerned with the kinematics of microcontinua. It begins with a discussion of strain, stress tensors, balanc...

  11. Effective quantum field theories

    International Nuclear Information System (INIS)

    Georgi, H.M.

    1989-01-01

    Certain dimensional parameters play a crucial role in the understanding of weak and strong interactions based on SU(2) x U(1) and SU(3) symmetry group theories and of grand unified theories (GUT's) based on SU(5). These parameters are the confinement scale of quantum chromodynamics and the breaking scales of SU(2) x U(1) and SU(5). The concepts of effective quantum field theories and renormalisability are discussed with reference to the economics and ethics of research. (U.K.)

  12. Noncommutative field theory

    International Nuclear Information System (INIS)

    Douglas, Michael R.; Nekrasov, Nikita A.

    2001-01-01

    This article reviews the generalization of field theory to space-time with noncommuting coordinates, starting with the basics and covering most of the active directions of research. Such theories are now known to emerge from limits of M theory and string theory and to describe quantum Hall states. In the last few years they have been studied intensively, and many qualitatively new phenomena have been discovered, on both the classical and the quantum level

  13. Energy from field crops

    Energy Technology Data Exchange (ETDEWEB)

    Zubr, J.

    1990-04-15

    At the Research Station of Royal Veterinary and Agricultural University, Copenhagen, Denmark, investigation concerning cultivation and exploitation of field crops for production of fuels was carried out during the period 1986-1989. High yielding crops, such as sugar beet - BETA VULGARIS, jerusalem artichoke - HELIANTHUS TUBEROSUS, rhubarb - RHEUM RHAPONTICUM, and comfrey - SYMPHYTUM ASPERUM, were grown experimentally in the field. Different cultivation methods for the crops were used and evaluated. Simultaneously with the field experiment, laboratory investigation was carried out to determine the energy potential of different products and by-products from the crops processes, such as alcoholic and methanogenic fermantation. Production expenses for the crops were determined, and cost of the fuels was estimated. The experimental results show that beet is a superior crop for the climatic conditions of Northern Europe. In the season 1986, yields exceeded 20 t TS/ha in the form of roots and tops, where achieved. A combined exploitation of beet roots and tops via alcoholic and methanogenic fermantation gave a gross energy corresponding to 80 hl OE/ha/yr. Using methanogenic fermentation exclusively, from ensiled beet roots and tops, gross energy yield corresponding to 85 hl IE/ha/yr, was achieved. The cost of energy in the form of alcohol from beet roots was estimated to be 5.17 DKK/1 OE (0.64 ECU/l OE). The cost of energy in the form of methane from ensiled beet tops, was estimated to be 2.68 DKK/l OE (0.33 ECU/l OE). At the present time, methane produced on the basis of ensiled beet roots and tops appears to be competitive with fossil fuels. Irrespective of the cost, however, the possibility of producing clean energy from field crops remains of interest for the future. (author) 27 refs.

  14. Quantized gauge field

    International Nuclear Information System (INIS)

    Arodz, H.

    1987-01-01

    The two formulations of quantum theory of the free electromagnetic field are presented. In the Coulomb gauge approach the independent dynamical variables have been identified and then, in order to quantize the theory, it has been sufficient to apply the straightforward canonical quantization. In the Gupta-Bleuler approach the auxilliary theory is first considered. The straightforward canonical quantization of it leads to the quantum theory defined in the space G with indefinite norm. 15 refs. (author)

  15. Affine field theories

    International Nuclear Information System (INIS)

    Cadavid, A.C.

    1989-01-01

    The author constructs a non-Abelian field theory by gauging a Kac-Moody algebra, obtaining an infinite tower of interacting vector fields and associated ghosts, that obey slightly modified Feynman rules. She discusses the spontaneous symmetry breaking of such theory via the Higgs mechanism. If the Higgs particle lies in the Cartan subalgebra of the Kac-Moody algebra, the previously massless vectors acquire a mass spectrum that is linear in the Kac-Moody index and has additional fine structure depending on the associated Lie algebra. She proceeds to show that there is no obstacle in implementing the affine extension of supersymmetric Yang-Mills theories. The result is valid in four, six and ten space-time dimensions. Then the affine extension of supergravity is investigated. She discusses only the loop algebra since the affine extension of the super-Poincare algebra appears inconsistent. The construction of the affine supergravity theory is carried out by the group manifold method and leads to an action describing infinite towers of spin 2 and spin 3/2 fields that interact subject to the symmetries of the loop algebra. The equations of motion satisfy the usual consistency check. Finally, she postulates a theory in which both the vector and scalar fields lie in the loop algebra of SO(3). This theory has an expanded soliton sector, and corresponding to the original 't Hooft-Polyakov solitonic solutions she now finds an infinite family of exact, special solutions of the new equations. She also proposes a perturbation method for obtaining an arbitrary solution of those equations for each level of the affine index

  16. Mobile Field Goniospectrometry

    Science.gov (United States)

    Peltoniemi, J. I.; Kaasalainen, S.; Näränen, J.

    2004-05-01

    Multiangle remote sensing needs multiangle models and multiangle ground reference data. The ground data can be measured using goniometers. Many targets are in difficult terrains and hard to bring into laboratory, which makes the ground data collection more complicated We have developed several field goniometers to measure the directional and spectral reflection signatures of various targets. The heaviest of the instruments is fully manual and very robust for field work. It can be transported using a light trailer and mounted in an hour. The new very light goniometer measures the BRDF automatically in few minutes. It can be carried by two persons even large distances to difficult places. Both of these instruments use the ASD Field Spec PRO FR spectrometer with a 4m light fibre allowing optics to be mounted up and the heavy parts down. The dimensions --- arm length about 2m --- and optics (1--8 degree view angles) limit the useful spot diameter to about 3, 10 or 30cm, making the system useful for small vegetation and soil. These two wide angle goniometers are complemented by a narrow angle backscattering goniometer utilising beamsplitters to measure up to exact backscattering direction and about 15 degree around. We present BRDF and spectra for undergrowth (lichen, moss, peat, twigs) from a field campaign in August 2003, and various grasses dry and wet. We recognise significant differences in the directional pattern between different species (factors of 2-10) and varying structural properties, making the use of directional signal for remote sensing very attractive. We are working with scattering models of snow and soil, and will continue with vegetation soon.

  17. Particles, fields, Universe

    International Nuclear Information System (INIS)

    Zeldovich, Ya. B.

    1984-01-01

    A general review is given on the historical development and on the present status of main physical ideas and theories. The concepts of particles, fields and interactions are discussed in detail including most recent developments. The present basic theories of physics: general relativity, gauge theory of electroweak interaction and quantum chromodynamics, their new results and their possible unification are analyzed. The author emphasizes the importance of knowledge as an inherent need of mankind. (D.Gy)

  18. Topics in field theory

    International Nuclear Information System (INIS)

    Velasco, E.S.

    1986-01-01

    This dissertation deals with several topics of field theory. Chapter I is a brief outline of the work presented in the next chapters. In chapter II, the Gauss-Bonnet-Chern theorem for manifolds with boundary is computed using the path integral representation of the Witten index for supersymmetric quantum mechanical systems. In chapter III the action of N = 2 (Poincare) supergravity is obtained in terms of N = 1 superfields. In chapter IV, N = 2 supergravity coupled to the (abelian) vector multiplet is projected into N - 1 superspace. There, the resulting set of constraints is solved in terms of unconstrained prepotential and the action in terms of N = 1 superfields is constructed. In chapter V the set of constraints for N = 2 conformal supergravity is projected into N = 1 superspace and solved in terms of N = 1 conformal supergravity fields a d matter prepotentials. In chapter VI the role of magnetic monopoles in the phase structure of the change one fixed length abelian Higgs model ins the latticer is investigated using analytic and numerical methods. The technique of monopole suppression is used to determine the phase transition lines that are monopole driven. Finally in chapter VII, the role of the charge of the Higgs field in the abelian Higgs model in the lattice is investigated

  19. Mapping the Field

    DEFF Research Database (Denmark)

    Goerres, Achim; Vanhuysse, Pieter

    2012-01-01

    Whereas the call for a political science based study of older people and ageing is not new (Cutler 1977; Heclo 1988), relatively little unified progress has been made so far. This chapter maps the field of generational politics and introduces our edited volume "Ageing Populations in Post-Industri......Whereas the call for a political science based study of older people and ageing is not new (Cutler 1977; Heclo 1988), relatively little unified progress has been made so far. This chapter maps the field of generational politics and introduces our edited volume "Ageing Populations in Post...... boxes by asking a number of central questions. How does population aging change political support for redistribution towards different age groups in society, including not just elderly people but also families with children? How, and when, do established parties in aging democracies implement policies......? The answers provided in this volume promise to be of major interest to scholars in fields such as political economy, political sociology, social policy, comparative politics, demography, and gerontology....

  20. Venus gravity fields

    Science.gov (United States)

    Sjogren, W. L.; Ananda, M.; Williams, B. G.; Birkeland, P. W.; Esposito, P. S.; Wimberly, R. N.; Ritke, S. J.

    1981-01-01

    Results of Pioneer Venus Orbiter observations concerning the gravity field of Venus are presented. The gravitational data was obtained from reductions of Doppler radio tracking data for the Orbiter, which is in a highly eccentric orbit with periapsis altitude varying from 145 to 180 km and nearly fixed periapsis latitude of 15 deg N. The global gravity field was obtained through the simultaneous estimation of the orbit state parameters and gravity coefficients from long-period variations in orbital element rates. The global field has been described with sixth degree and order spherical harmonic coefficients, which are capable of resolving the three major topographical features on Venus. Local anomalies have been mapped using line-of-sight accelerations derived from the Doppler residuals between 40 deg N and 10 deg S latitude at approximately 300 km spatial resolution. Gravitational data is observed to correspond to topographical data obtained by radar altimeter, with most of the gravitational anomalies about 20-30 milligals. Simulations evaluating the isostatic states of two topographic features indicate that at least partial isostasy prevails, with the possibility of complete compensation.

  1. Heavy fields and gravity

    Energy Technology Data Exchange (ETDEWEB)

    Goon, Garrett [Institute of Physics, Universiteit van Amsterdam,Science Park 904, Amsterdam, 1090 GL (Netherlands)

    2017-01-11

    We study the effects of heavy fields on 4D spacetimes with flat, de Sitter and anti-de Sitter asymptotics. At low energies, matter generates specific, calculable higher derivative corrections to the GR action which perturbatively alter the Schwarzschild-(A)dS family of solutions. The effects of massive scalars, Dirac spinors and gauge fields are each considered. The six-derivative operators they produce, such as ∼R{sup 3} terms, generate the leading corrections. The induced changes to horizon radii, Hawking temperatures and entropies are found. Modifications to the energy of large AdS black holes are derived by imposing the first law. An explicit demonstration of the replica trick is provided, as it is used to derive black hole and cosmological horizon entropies. Considering entropy bounds, it’s found that scalars and fermions increase the entropy one can store inside a region bounded by a sphere of fixed size, but vectors lead to a decrease, oddly. We also demonstrate, however, that many of the corrections fall below the resolving power of the effective field theory and are therefore untrustworthy. Defining properties of black holes, such as the horizon area and Hawking temperature, prove to be remarkably robust against higher derivative gravitational corrections.

  2. In-field analysis

    International Nuclear Information System (INIS)

    Stewart, Richard

    2010-01-01

    Full text: A new technology for in-field measurement of hydrocarbons in soil promises rapid results. Standard industry practice in Australia for measuring hydrocarbons in soil is to send a soil sample to an off-site accredited laboratory for analysis. This typically costs $25-50 per sample and takes 5-7 days to turnaround the results. While there are in-field hydrocarbon measurement technologies available in the US, most involve extracting the hydrocarbons from the soil and analysing the resulting liquid. These methods are time- consuming and often involve toxic solvents and clumsy equipment. A new technology developed by Ziltek and CSIRO allows for real-time me as-urement in the field. The user simply pulls the trigger on a hand-held infrared spectrometer and within a few seconds gets a digital read-out of the hydrocarbon concentration. The technology requires no toxic solvents or consumables, and sampling positions can also be logged automatically using GPS coordinates. A new technology developed by Ziltek and CSIRO allows for real-time measurement in the field. The user simply pulls the trigger on a hand-held infrared spectrometer and within a few seconds gets a digital read-out of the hydrocarbon concentration. The technology requires no toxic solvents or consumables, and sampling positions can also be logged automatically using GPS coordinates. The technology is essentially a software application that can be used with any third-party supplied hand-held infrared device. A working prototype has been tested at several contaminated sites across Australia, with very promising results. The site trials involved taking in-situ measurements using an infrared instrument before sending the soil to an external laboratory for conventional analysis - and comparing the results. Ziltek technical director Dr Ben Dearman noted at some sites the variation between the infrared results and lab results was less than 10 per cent.The technology gives a single concentration value in

  3. El turismo cultural: gestión de partes interesadas y la complejidad del equilibrio

    Directory of Open Access Journals (Sweden)

    Ascanio, Alfredo

    2009-01-01

    Full Text Available The balance of sustainable development is possible provided that the stakeholders concerned work together. In 1999 began developing normative planning model based in coordinating the interests of stakeholders in tourism. This tool would balance the interests of the parties involved and their services. This involves implementing market segmentation strategies, as suggested by experts in tourism mar-keting Elise Truly Sautter Birgit Leiser.

  4. Equilibrio de fases de sistemas compostos por oleos vegetais, acidos graxos e etanol hidratado.

    OpenAIRE

    Cintia Bernardo Gonçalves

    2004-01-01

    Resumo: Este trabalho de tese de doutoramento teve como objetivo avaliar vários aspectos do processo de extração líquido-líquido (ELL) como uma rota alternativa para a desacidificação de óleos vegetais. O conhecimento do equilíbrio de fases do sistema de interesse é essencial para o bom planejamento e desenvolvimento do processo de ELL. O presente trabalho apresenta dados de equilíbrio para sistemas compostos por óleos vegetais (milho/palma), ácidos graxos (oléico/ palmítico) e solvente (etan...

  5. Reacciones precipitación: ecuaciones, diagramas y relación con otros equilibrios

    OpenAIRE

    Reyes Labarta, Juan Antonio

    2010-01-01

    Condiciones de precipitación y de disolución. Comienzo y final de precipitación. Precipitación fraccionada. Factores que afectan a la solubilidad de precipitados. Factores que afectan al valor de KS. Factores que afectan al valor del producto iónico. Reacciones de desplazamiento. Desplazamiento por reacciones ácido-base. Desplazamiento por formación de complejos. Desplazamiento por reacciones redox. Diagramas de área de predominio con existencia de precipitado. Otros aspectos de la precipitac...

  6. Influencia do indice de massa corporal no equilibrio e na configuracao plantar em obesos adultos

    Directory of Open Access Journals (Sweden)

    Liu Chiao Yi

    2014-01-01

    Full Text Available INTRODUÇÃO: A obesidade é uma doença crônica degenerativa multifatorial que pode levar a alterações do sistema musculoesquelético, como mudança do centro de gravidade e sobrecarga mecânica sobre os membros inferiores. OBJETIVOS: Correlacionar o índice de massa corporal (IMC com o equilíbrio corporal e verificar associação entre o IMC e a configuração plantar. MÉTODOS: Foram avaliados 30 obesos, de ambos os gêneros, com IMC maior ou igual a 30 Kg/m². Inicialmente, os voluntários foram submetidos às avaliações de medidas antropométricas a fim de calcular o valor do IMC. Em seguida, foram submetidos ao teste de equilíbrio corporal estático Balance Error Scoring System (BESS e a plantigrafia para a identificação da impressão plantar. Por meio do método de Viladot, os voluntários foram classificados em grupos: pé plano (GPP, pé cavo (GPC e pé neutro (GPN. A correlação entre as variáveis IMC e BESS foi calculada por meio do coeficiente de correlação linear de Pearson e associação entre o IMC e a configuração plantar foi realizada por meio da análise de variância (Anova. Para todas as análises, nível de significância considerado foi p < 0,05. RESULTADOS: Os valores da correlação entre o IMC e o BESS foram r = - 0,1 e p = 0,59. Os valores da associação do IMC entre GPN - GPP; GPN - GPC; GPP - GPC foram respectivamente: p = 0,76; p = 0,001; p = 0,07. CONCLUSÃO: O índice de massa corporal de adultos obesos não influencia o equilíbrio corporal, porém influencia na configuração plantar.

  7. Complejidad, equilibrio y finanzas: conceptos y herramientas para la gestión de empresas sostenibles

    Directory of Open Access Journals (Sweden)

    Jorge Saravía Ríos

    2013-08-01

    Full Text Available Las organizaciones insertas en un entorno complejo deben ser estructuras dinámicas y flexibles, con capacidad de fijar metas concretas y construir metodologías efectivas para guiar y monitorear su avance en la dirección correcta. Quizá la meta más universal para una organización compleja es el ser sostenible; el problema de la sostenibilidad como meta es que puede observarse desde un gran número de perspectivas y generar diversas interpretaciones. Peguntas como ¿Ser sostenible acaso no significa ser mediocre? ¿A quién le interesa ser sostenible, al accionista o al empleado? ¿Qué se gana siendo sostenible? ¿Ser sostenible significa tener más plata? ¿Ser sostenible equivale a tener la mayor participación en el mercado? ¿Soy sostenible si soy rentable? dejan ver que sin una estandarización de ese “ser sostenible” y sin la existencia de un modelo formal que permita su “medición” no será posible usarlo como meta y no se contará con una herramienta válida de gestión.

  8. Un approccio di equilibrio finanziario di lungo periodo ai problemi di un sistema pensionistico a ripartizione

    Directory of Open Access Journals (Sweden)

    A. NICCOLI

    2013-10-01

    Full Text Available The article compares the distributional features of pay-as-you-go and fully funded pension systems. It analyses in particular the tendencies of pay-as-you-go systems to offer vary high benefits and internal rate of returns at the beginning of their establishment, while being subject to increasingly painful cuts in benefits over time. The author concludes that a mixed system exhibiting features of both pay-as-you-go and fully funded pension systems may be the optimal one. JEL Codes: H55 

  9. Stabilità dei prezzi ed equilibrio dei conti pubblici quale condizione per uno sviluppo duraturo

    Directory of Open Access Journals (Sweden)

    Carlo Azeglio Ciampi

    2012-04-01

    Full Text Available The article illustrates Italy's economie recovery as part of a process of re­newal involving the institutions, every area of the economy and ltalian socie­tyas a whole. After the turning point in 1992, a generaI consensus emerged that European integration was necessary and fully consistent with the natio­nal interest. In this context, the three components of economie policy ­budgetary policy, incomes policy, monetary policy -are working in tandem, ensuring stability, the essential condition for any lasting and sustainable growth. Thus inflation has now been beaten; the balance of payments on current account has recorded increasing and substantial surpluses, and there has been a huge reduction in the budget deficit, with a large primary surplus. The sustainability of these results is ensured by the implementation of structural reforms: tax reform, reform of centraI government budget, reform of the civil service, pensions reform and reform of Italy's commercial system.  JEL Codes: E65 

  10. Diferencias de productividad en Europa. Equilibrio a corto y largo plazo

    OpenAIRE

    Decimavilla Herrero, Esther; San Juan Mesonada, Carlos

    2000-01-01

    Este artículo discute los resultados de medir la Productividad Total de los Factores (PTF) de las empresas agrarias europeas con distintos índices. El enfoque que utilizamos está basado en el cálculo de índices de Productividad Total de los Factores, lo que nos permite obtener formas flexibles para captar la tecnología subyacente y un procedimiento de cálculo apropiado para usar datos contables de las empresas. Con el fin de comparar la evolución en el tiempo de la productividad de las explot...

  11. El equilibrio entre actividades interactivas y no interactivas de los professores universitarios

    Directory of Open Access Journals (Sweden)

    Joaquin Maria Azagra

    2006-01-01

    Full Text Available Se desarrolla un modelo económico de elección individual en el que el profesor universitário maximiza una función de utilidad. Se obtiene un óptimo interior de esfuerzo interactivo quedepende de los parámetros de la función de utilidad, el salario, los ingresos derivados de lãs actividades interactivas, su ponderación en la determinación del prestigio y su contribución al conocimiento. El modelo se contrasta econométricamente utilizando una muestra de 380 profesores de la Comunidad Valenciana, una región española. El profesor responde más a incentivos no monetarios que a monetarios y a la dificultad de producir conocimiento no interactivo frente a interactivo. Además, es posible la existencia de racionamiento, ya que lainteracción deseada y la real difieren. Las iniciativas de política podrían plantearse la acciónsobre la interacción universidad-empresa como un objetivo a largo plazo y la detección desituaciones que se derivan de un posible racionamiento.

  12. O equilibrio entre a atividade económica e a sustentabilidade socio-ambiental

    Directory of Open Access Journals (Sweden)

    João Meirelles Filho

    2004-11-01

    Full Text Available El ecoturismo ha surgido a partir de las nuevas tendencias del mercado, el cual busca un espacio de reencuentro e interacción no sólo con la naturaleza sino también con las comunidades locales, como una experiencia integral que le permita alejarse de la cotidianidad y el estrés de las metrópolis. Sin embargo, aún es una actividad de pequeña escala en la economía brasileña, que requiere de una adecuada planificación y control. El autor hace una breve descripción del porqué del desarrollo actual de las actividades ecoturísticas para el disfrute y entretenimiento en los tiempos de ocio de las personas, haciendo referencia a las características y segmentación de la demanda y a la situación actual de esta actividad en Brasil.

  13. Uso de chimeneas de equilibrio con cámara de aire en instalaciones por gravedad

    Directory of Open Access Journals (Sweden)

    Jorge Armando Granados Robayo

    1987-09-01

    Full Text Available Este articulo surgió de una inquietud personal del autor ante la falta de bibliografla para solucionar problemas de Golpe de ariete en sistemas por gravedad, especialmente en microcentrales. La investigación se desarrolló mediante dos proyectos de grado para ingenieros civiles, el primero por Alvaro Ramlrez Calderón y el segundo por Germán Nava Gutiérrez y Martha Lucia Avila González.

  14. Introduction to gauge field theory

    International Nuclear Information System (INIS)

    Bailin, David; Love, Alexander

    1986-01-01

    The book is intended as an introduction to gauge field theory for the postgraduate student of theoretical particle physics. The topics discussed in the book include: path integrals, classical and quantum field theory, scattering amplitudes, feynman rules, renormalisation, gauge field theories, spontaneous symmetry breaking, grand unified theory, and field theories at finite temperature. (UK)

  15. Quantum fields in curved space

    International Nuclear Information System (INIS)

    Birrell, N.D.; Davies, P.C.W.

    1982-01-01

    The book presents a comprehensive review of the subject of gravitational effects in quantum field theory. Quantum field theory in Minkowski space, quantum field theory in curved spacetime, flat spacetime examples, curved spacetime examples, stress-tensor renormalization, applications of renormalization techniques, quantum black holes and interacting fields are all discussed in detail. (U.K.)

  16. Quality for quantum free fields

    International Nuclear Information System (INIS)

    Leyland, Pen; Roberts, John; Testard, Daniel; Centre National de la Recherche Scientifique, 13 - Marseille

    1978-07-01

    A proof is given concerning duality for the free neutral scalar boson field (abstract duality). Then real subspaces of a complex Hilbert space and the Von Neumann algebra associated with real subspaces are considered. Lastly duality for free fields (free electromagnetic field and free scalar field of any mass) is studied

  17. Stochastic quantization of Proca field

    International Nuclear Information System (INIS)

    Lim, S.C.

    1981-03-01

    We discuss the complications that arise in the application of Nelson's stochastic quantization scheme to classical Proca field. One consistent way to obtain spin-one massive stochastic field is given. It is found that the result of Guerra et al on the connection between ground state stochastic field and the corresponding Euclidean-Markov field extends to the spin-one case. (author)

  18. Covariant field equations in supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Vanhecke, Bram [KU Leuven, Institute for Theoretical Physics, Leuven (Belgium); Ghent University, Faculty of Physics, Gent (Belgium); Proeyen, Antoine van [KU Leuven, Institute for Theoretical Physics, Leuven (Belgium)

    2017-12-15

    Covariance is a useful property for handling supergravity theories. In this paper, we prove a covariance property of supergravity field equations: under reasonable conditions, field equations of supergravity are covariant modulo other field equations. We prove that for any supergravity there exist such covariant equations of motion, other than the regular equations of motion, that are equivalent to the latter. The relations that we find between field equations and their covariant form can be used to obtain multiplets of field equations. In practice, the covariant field equations are easily found by simply covariantizing the ordinary field equations. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Covariant field equations in supergravity

    International Nuclear Information System (INIS)

    Vanhecke, Bram; Proeyen, Antoine van

    2017-01-01

    Covariance is a useful property for handling supergravity theories. In this paper, we prove a covariance property of supergravity field equations: under reasonable conditions, field equations of supergravity are covariant modulo other field equations. We prove that for any supergravity there exist such covariant equations of motion, other than the regular equations of motion, that are equivalent to the latter. The relations that we find between field equations and their covariant form can be used to obtain multiplets of field equations. In practice, the covariant field equations are easily found by simply covariantizing the ordinary field equations. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. Vector Fields on Product Manifolds

    OpenAIRE

    Kurz, Stefan

    2011-01-01

    This short report establishes some basic properties of smooth vector fields on product manifolds. The main results are: (i) On a product manifold there always exists a direct sum decomposition into horizontal and vertical vector fields. (ii) Horizontal and vertical vector fields are naturally isomorphic to smooth families of vector fields defined on the factors. Vector fields are regarded as derivations of the algebra of smooth functions.

  1. Unbalanced field RF electron gun

    Science.gov (United States)

    Hofler, Alicia

    2013-11-12

    A design for an RF electron gun having a gun cavity utilizing an unbalanced electric field arrangement. Essentially, the electric field in the first (partial) cell has higher field strength than the electric field in the second (full) cell of the electron gun. The accompanying method discloses the use of the unbalanced field arrangement in the operation of an RF electron gun in order to accelerate an electron beam.

  2. Workplace photon radiation fields

    International Nuclear Information System (INIS)

    Burgess, P.H.; Bartlett, D.T.; Ambrosi, P.

    1999-01-01

    The knowledge of workplace radiation fields is essential for measures in radiation protection. Information about the energy and directional distribution of the incident photon radiation was obtained by several devices developed by the National Radiation Protection Board, United Kingdom, by the Statens Stralskyddsinstitut, Sweden, together with EURADOS and by the Physikalisch-Technische Bundesanstalt, Germany. The devices are described and some results obtained at workplaces in nuclear industry, medicine and science in the photon energy range from 20 keV to 7 MeV are given. (author)

  3. Near field communications handbook

    CERN Document Server

    Ahson, Syed A; Furht, Borko

    2011-01-01

    Near Field Communication, or NFC, is a short-range high frequency wireless communication technology that enables the exchange of data between devices over about a decimeter. The technology is a simple extension of the ISO 14443 proximity-card standard (contact less card, RFID) that combines the interface of a smart card and a reader into a single device with practical implications. A complete reference for NFC, this handbook provides technical information about all aspects of NFC, as well as applications. It covers basic concepts as well as research grade material and includes a discussion of

  4. Topics in field theory

    CERN Document Server

    Karpilovsky, G

    1989-01-01

    This monograph gives a systematic account of certain important topics pertaining to field theory, including the central ideas, basic results and fundamental methods.Avoiding excessive technical detail, the book is intended for the student who has completed the equivalent of a standard first-year graduate algebra course. Thus it is assumed that the reader is familiar with basic ring-theoretic and group-theoretic concepts. A chapter on algebraic preliminaries is included, as well as a fairly large bibliography of works which are either directly relevant to the text or offer supplementary material of interest.

  5. Geometrical description of fields

    International Nuclear Information System (INIS)

    Sokolik, H.

    1979-01-01

    The author suggests a purely algebraic interpretation of interaction. The main idea is to consider interaction as a deformation of an inhomogeneous algebra composed of momentum operators and an arbitrary group admitting the equation of the theory. The only difference between this approach and the conventional one is that the generalized momentum operators do not commute with aech other, due not merely to the introduction of some external interaction field, but to the change of the structure of the algebra from which the theory stems

  6. Holographic effective field theories

    Energy Technology Data Exchange (ETDEWEB)

    Martucci, Luca [Dipartimento di Fisica ed Astronomia “Galileo Galilei' , Università di Padova,and INFN - Sezione di Padova, Via Marzolo 8, I-35131 Padova (Italy); Zaffaroni, Alberto [Dipartimento di Fisica, Università di Milano-Bicocca,and INFN - Sezione di Milano-Bicocca, I-20126 Milano (Italy)

    2016-06-28

    We derive the four-dimensional low-energy effective field theory governing the moduli space of strongly coupled superconformal quiver gauge theories associated with D3-branes at Calabi-Yau conical singularities in the holographic regime of validity. We use the dual supergravity description provided by warped resolved conical geometries with mobile D3-branes. Information on the baryonic directions of the moduli space is also obtained by using wrapped Euclidean D3-branes. We illustrate our general results by discussing in detail their application to the Klebanov-Witten model.

  7. High Field Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1984-12-15

    A Workshop was held in Frascati at the end of September under the title 'Generation of High Fields for Particle Acceleration to Very High Energies'. It was organized by the CERN Accelerator School, the European Committee for Future Accelerators (ECFA) and the Italian INFN and was a further stage in the exploratory moves towards new techniques of acceleration. Such techniques might become necessary to respond to the needs of high energy physics some decades from now when the application of conventional techniques will probably have reached their limits.

  8. Beyond the field

    DEFF Research Database (Denmark)

    Larsen, Anna Folke; Lilleør, Helene Bie

    2014-01-01

    We estimate the impact of a Farmer Field School intervention among small-scale farmers in northern Tanzania on two main development objectives: food security and poverty. We employ a series of evaluation methodologies, including a Quasi-Difference-in-Difference setup, to account for potential...... selection into the project, despite lack of baseline data. We find strong positive effects on food security, but no effect on poverty. Investigating possible mechanisms for this result shows that reallocation of labor resources toward own agricultural production and improved production smoothing may have...

  9. Quantum fields and dissipation

    International Nuclear Information System (INIS)

    Henning, P.

    1996-06-01

    The description of thermal or non-equilibrium systems necessitates a quantum field theory which differs from the usual approach in two aspects: 1. The Hilbert space is doubled; 2. Stable quasi-particles do not exist in interacting systems. A mini-review of these two aspects is given from a practical viewpoint including two applications. For thermal states it is shown how infrared divergences occuring in perturbative quasi-particle theories are avoided, whereas for non-equilibrium states a memory effect is shown to arise in the thermalization. (orig.)

  10. Higgs Effective Field Theories

    CERN Document Server

    2016-01-01

    The main focus of this meeting is to present new theoretical advancements related to effective field theories, evaluate the impact of initial results from the LHC Run2, and discuss proposals for data interpretation/presentation during Run2. A crucial role of the meeting is to bring together theorists from different backgrounds and with different viewpoints and to extend bridges towards the experimental community. To this end, we would like to achieve a good balance between senior and junior speakers, enhancing the visibility of younger scientists while keeping some overview talks.

  11. The First Chandra Field

    Energy Technology Data Exchange (ETDEWEB)

    Weisskopf, Martin C.; /NASA, Marshall; Aldcroft, Thomas L.; /Harvard-Smithsonian Ctr. Astrophys.; Cameron, Robert A.; /Harvard-Smithsonian Ctr. Astrophys. /SLAC; Gandhi,; Foellmi, Cedric; /European Southern Obs., Chile; Elsner, Ronald F.; /NASA, Marshall; Patel, Sandeep K.; /USRA, Huntsville; Wu, Kinwah; /Mullard Space Sci. Lab.; O' Dell, Stephen; /NASA, Marshall

    2005-09-09

    Before the official first-light images, the Chandra X-ray Observatory obtained an X-ray image of the field to which its focal plane was first exposed. We describe this historic observation and report our study of the first Chandra field. Chandra's Advanced CCD Imaging Spectrometer (ACIS) detected 15 X-ray sources, the brightest being dubbed ''Leon X-1'' to honor the Chandra Telescope Scientist, Leon Van Speybroeck. Based upon our analysis of the X-ray data and spectroscopy at the European Southern Observatory (ESO; La Silla, Chile), we find that Leon X-1 is a Type-1 (unobscured) active galactic nucleus (AGN) at a redshift z = 0.3207. Leon X-1 exhibits strong Fe II emission and a broad-line Balmer decrement that is unusually flat for an AGN. Within the context of the Eigenvector-1 correlation space, these properties suggest that Leon X-1 may be a massive ({ge} 10{sup 9} M{sub {circle_dot}}) black hole, accreting at a rate approaching its Eddington limit.

  12. Measurement of radiofrequency fields

    International Nuclear Information System (INIS)

    Leonowich, J.A.

    1992-05-01

    We are literally surrounded by radiofrequency (RFR) and microwave radiation, from both natural and man-made sources. The identification and control of man-made sources of RFR has become a high priority of radiation safety professionals in recent years. For the purposes of this paper, we will consider RFR to cover the frequencies from 3 kHz to 300 MHz, and microwaves from 300 MHz to 300 GHz, and will use the term RFR interchangeably to describe both. Electromagnetic radiation and field below 3 kHz is considered Extremely Low Frequency (ELF) and will not be discussed in this paper. Unlike x- and gamma radiation, RFR is non-ionizing. The energy of any RFR photon is insufficient to produce ionizations in matter. The measurement and control of RFR hazards is therefore fundamentally different from ionizing radiation. The purpose of this paper is to acquaint the reader with the fundamental issues involved in measuring and safely using RFR fields. 23 refs

  13. Gauge field theory

    International Nuclear Information System (INIS)

    Aref'eva, I.Ya.; Slavnov, A.A.

    1981-01-01

    This lecture is devoted to the discussion of gauge field theory permitting from the single point of view to describe all the interactions of elementary particles. The authors used electrodynamics and the Einstein theory of gravity to search for a renormgroup fixing a form of Lagrangian. It is shown that the gauge invariance added with the requirement of the minimum number of arbitraries in Lagrangian fixes unambigously the form of the electromagnetic interaction. The generalization of this construction for more complicate charge spaces results in the Yang-Mills theory. The interaction form in this theory is fixed with the relativity principle in the charge space. A quantum scheme of the Yang-Mills fields through the explicit separation of true dynamic variables is suggested. A comfortable relativistically invariant diagram technique for the calculation of a producing potential for the Green functions is described. The Ward generalized identities have been obtained and a procedure of the elimination of ultraviolet and infrared divergencies has been accomplished. Within the framework of QCD (quantum-chromodynamic) the phenomenon of the asymptotic freedom being the most successful prediction of the gauge theory of strong interactions was described. Working methods with QCD outside the framework of the perturbation theory have been described from a coupling constant. QCD is represented as a single theory possessing both the asymptotical freedom and the freedom retaining quarks [ru

  14. Conformal invariant quantum field theory and composite field operators

    International Nuclear Information System (INIS)

    Kurak, V.

    1976-01-01

    The present status of conformal invariance in quantum field theory is reviewed from a non group theoretical point of view. Composite field operators dimensions are computed in some simple models and related to conformal symmetry

  15. UVIS Flat Field Uniformity

    Science.gov (United States)

    Quijano, Jessica Kim

    2009-07-01

    The stability and uniformity of the low-frequency flat fields {L-flat} of the UVIS detector will be assessed by using multiple-pointing observations of the globular clusters 47 Tucanae {NGC104} and Omega Centauri {NGC5139}, thus imaging moderately dense stellar fields. By placing the same star over different portions of the detector and measuring relative changes in its brightness, it will be possible to determine local variations in the response of the UVIS detector. Based on previous experience with STIS and ACS, it is deemed that a total of 9 different pointings will suffice to provide adequate characterization of the flat field stability in any given band. For each filter to be tested, the baseline consists of 9 pointings in a 3X3 box pattern with dither steps of about 25% of the FOV, or 40.5", in either the x or y direction {useful also for CTE measurements, if needed in the future}. During SMOV, the complement of filters to be tested is limited to the following 6 filters: F225W, F275W, F336W, for Omega Cen, and F438W, F606W, and F814W for 47 Tuc. Three long exposures for each target are arranged such that the initial dither position is observed with the appropriate filters for that target within one orbit at a single pointing, so that filter-to-filter differences in the observed star positions can be checked. In addition to the 9 baseline exposures, two sets of short exposures will be taken:a} one short exposure will be taken of OmegaCen with each of the visible filters {F438W, F606W and F814W} in order to check the geometric distortion solution to be obtained with the data from proposal 11444;b} for each target, a single short exposure will be taken with each filter to facilitate the study of the PSF as a function of position on the detector by providing unsaturated images of sparsely-spaced bright stars.This proposal corresponds to Activity Description ID WF39. It should execute only after the following proposal has executed:WF21 - 11434

  16. Electron-Cloud Wake Fields

    CERN Document Server

    Rumolo, Giovanni

    2002-01-01

    The electron cloud gives rise to coherent and incoherent single-bunch wake fields, both in the longitudinal and in the transverse direction, and to coherent coupled-bunch wakes. These wake fields can be computed using the simulation programs ECLOUD and HEADTAIL developed at CERN. We present the wake fields simulated for the LHC beam in the CERN SPS and at injection into the LHC in different magnetic field configurations (field-free region, dipole, and solenoid), where the magnetic field affects both the elec-tron motion during a bunch passage and the overall electron distribution in the beam pipe.

  17. The Emerging Strategic Entrepreneurship Field

    DEFF Research Database (Denmark)

    Foss, Nicolai Juul; Lyngsie, Jacob

    The field of strategic entrepreneurship is a fairly recent one. Its central idea is that opportunity-seeking and advantage-seeking — the former the central subject of the entrepreneurship field, the latter the central subject of the strategic management field — are processes that need...... to be considered jointly. The purpose of this brief chapter is to explain the emergence of SE theory field in terms of a response to research gaps in the neighboring fields of entrepreneurship and strategic management; describe the main tenets of SE theory; discuss its relations to neighboring fields; and finally...

  18. Magnetic fields in diffuse media

    CERN Document Server

    Pino, Elisabete; Melioli, Claudio

    2015-01-01

    This volume presents the current knowledge of magnetic fields in diffuse astrophysical media. Starting with an overview of 21st century instrumentation to observe astrophysical magnetic fields, the chapters cover observational techniques, origin of magnetic fields, magnetic turbulence, basic processes in magnetized fluids, the role of magnetic fields for cosmic rays, in the interstellar medium and for star formation. Written by a group of leading experts the book represents an excellent overview of the field. Nonspecialists will find sufficient background to enter the field and be able to appreciate the state of the art.

  19. Two field formulation of closed string field theory

    International Nuclear Information System (INIS)

    Bogojevic, A.R.

    1990-09-01

    A formulation of closed string field theory is presented that is based on a two field action. It represents a generalization of Witten's Chern-Simons formulation of 3d gravity. The action contains only 3 string interactions and no string field truncations, unlike the previous non-polynomial action of Zwiebach. The two field action is found to follow from a purely cubic, background independent action similar to the one for open strings. (orig.)

  20. Fractional Stochastic Field Theory

    Science.gov (United States)

    Honkonen, Juha

    2018-02-01

    Models describing evolution of physical, chemical, biological, social and financial processes are often formulated as differential equations with the understanding that they are large-scale equations for averages of quantities describing intrinsically random processes. Explicit account of randomness may lead to significant changes in the asymptotic behaviour (anomalous scaling) in such models especially in low spatial dimensions, which in many cases may be captured with the use of the renormalization group. Anomalous scaling and memory effects may also be introduced with the use of fractional derivatives and fractional noise. Construction of renormalized stochastic field theory with fractional derivatives and fractional noise in the underlying stochastic differential equations and master equations and the interplay between fluctuation-induced and built-in anomalous scaling behaviour is reviewed and discussed.

  1. Introduction to field theory

    CERN Multimedia

    CERN. Geneva; CERN. Geneva

    2001-01-01

    Starting from the notion of path integrals as developed by Feynman, we discuss field theory in zero spacetime dimensions. The concepts of perturbation expansions, connected amplitudes, Feynman diagrams, classical solutions, renormalization and the effective action are developed. The model is extended to four spacetime dimensions, and the full Feynman rules for relativisitc scalar theory derived. The S matrix and the concept of unitarity are discussed, leading to the amputation rules for S matrix elements from considerations of unitarity. The rules are extended to include particles with spin-1/2 and spin-1. The high-energy behaviour of the theory is discussed as a method to derive the gauge symmetry of the various models.

  2. High field electron linacs

    International Nuclear Information System (INIS)

    Le Duff, J.

    1985-12-01

    High field electron linacs are considered as potential candidates to provide very high energies beyond LEP. Since almost twenty years not much improvement has been made on linac technologies as they have been mostly kept at low and medium energies to be used as injectors for storage rings. Today, both their efficiency and their performances are being reconsidered, and for instance the pulse compression sheme developed at SLAC and introduced to upgrade the energy of that linac is a first step towards a new generation of linear accelerators. However this is not enough in terms of power consumption and more development is needed to improve both the efficiency of accelerating structures and the performances of RF power sources

  3. High field superconducting magnets

    Science.gov (United States)

    Hait, Thomas P. (Inventor); Shirron, Peter J. (Inventor)

    2011-01-01

    A superconducting magnet includes an insulating layer disposed about the surface of a mandrel; a superconducting wire wound in adjacent turns about the mandrel to form the superconducting magnet, wherein the superconducting wire is in thermal communication with the mandrel, and the superconducting magnet has a field-to-current ratio equal to or greater than 1.1 Tesla per Ampere; a thermally conductive potting material configured to fill interstices between the adjacent turns, wherein the thermally conductive potting material and the superconducting wire provide a path for dissipation of heat; and a voltage limiting device disposed across each end of the superconducting wire, wherein the voltage limiting device is configured to prevent a voltage excursion across the superconducting wire during quench of the superconducting magnet.

  4. Fast harmonic field mapper

    International Nuclear Information System (INIS)

    Au, R.; Fowler, M.; Hanawa, H.; Riedel, J.; Qua, Z.G.

    1984-01-01

    In early 1983 it was decided to mount coils on arms separated by 120 degrees and buck them out so that the third harmonic dphi/dt component would be cancelled and thus the first and second field harmonics could be very accurately measured. The original intention was to do as others had done, namely, use fast ADC's to read the voltages, and computer process the result to get the Fourier components. However, because of the 100 to 1 dynamic range of the fast ADC's and the likelihood that noise would be a problem, the authors decided to do things differently. Using a fast Fourier transform analyzer was considered, but this instrument is very expensive, so they decided to use a completely electronic analog approach: The authors decided to use active bandpass filters to render the harmonic components

  5. Conflict field energy

    International Nuclear Information System (INIS)

    Krebsbach-Gnath, C.

    1981-01-01

    Violent social controversies characterize the treatment of the energy problem. Solutions of this conflict decisively depend on the knowledge and evaluation of the causes and the possible development. How is it possible to explain the opinions, views, and the attitude of the population to different kinds of energy. Which factors are decisive for the explosive effect and the stability of the conflict in the field of nulcear energy. What will happen when there arises a possible lack of energy. Which socio-political effects will such a lack have. Are there new proposals for solving problems in the nulcear-energy debate. The contributions of this book are results of scientific and empiric works. They provide perceptive approaches and analyses to the problems and by discussing them are useful in giving an orientation for political action. (orig.) [de

  6. Field theory of strings

    International Nuclear Information System (INIS)

    Ramond, P.

    1987-01-01

    We review the construction of the free equations of motion for open and closed strings in 26 dimensions, using the methods of the Florida Group. Differing from previous treatments, we argue that the constraint L 0 -anti L 0 =0 should not be imposed on all the fields of the closed string in the gauge invariant formalism; we show that it can be incorporated in the gauge invariant formalism at the price of being unable to extract the equations of motion from a Langrangian. We then describe our purely algebraic method to introduce interactions, which works equally well for open and closed strings. Quartic interactions are absent except in the Physical Gauge. Finally, we speculate on the role of the measure of the open string path functional. (orig.)

  7. Gauge field models

    International Nuclear Information System (INIS)

    Becchi, C.; Rouet, A.; Stora, R.

    1975-10-01

    Stora's analysis is continued in discussing the nonabelian (Yang-Mills) gauge field models (G.F.M.). The gauge independence of the physical scattering operator is discussed in some details and the connection between its unitary and the Slavnov symmetry outlined. Only the models involving semisimple gauge groups are considered. This greatly simplifies the analysis of the possible quantum corrections to the Quantum Action Principle which is reduced to the study of the cohomology group of the Lie algebra characterizing the gauge theory. The discussion is at the classical level for the algebraic properties of the SU(2) Higgs-Kibble-Englert-Brout-Faddeev-Popov lagrangian and its invariance under Slavnov identity transformations is exhibited. The renormalization of the Slavnov identity in the G.M.F. involving semisimple gauge groups is studied. The unitary and gauge independence of the physical S operator in the SU(2) H.K. model is dealt with [fr

  8. Strong field laser physics

    CERN Document Server

    2008-01-01

    Since the invention of the laser in the 1960s, people have strived to reach higher intensities and shorter pulse durations. High intensities and ultrashort pulse durations are intimately related. Recent developments have shown that high intensity lasers also open the way to realize pulses with the shortest durations to date, giving birth to the field of attosecond science (1 asec = 10-18s). This book is about high-intensity lasers and their applications. The goal is to give an up to date introduction to the technology behind these laser systems and to the broad range of intense laser applications. These applications include AMO (atomic molecular and optical) physics, x-ray science, attosecond science, plasma physics and particle acceleration, condensed matter science and laser micromachining, and finally even high-energy physics.

  9. Asymmetrical field emitter

    Science.gov (United States)

    Fleming, J.G.; Smith, B.K.

    1995-10-10

    A method is disclosed for providing a field emitter with an asymmetrical emitter structure having a very sharp tip in close proximity to its gate. One preferred embodiment of the present invention includes an asymmetrical emitter and a gate. The emitter having a tip and a side is coupled to a substrate. The gate is connected to a step in the substrate. The step has a top surface and a side wall that is substantially parallel to the side of the emitter. The tip of the emitter is in close proximity to the gate. The emitter is at an emitter potential, and the gate is at a gate potential such that with the two potentials at appropriate values, electrons are emitted from the emitter. In one embodiment, the gate is separated from the emitter by an oxide layer, and the emitter is etched anisotropically to form its tip and its asymmetrical structure. 17 figs.

  10. A general field-covariant formulation of quantum field theory

    International Nuclear Information System (INIS)

    Anselmi, Damiano

    2013-01-01

    In all nontrivial cases renormalization, as it is usually formulated, is not a change of integration variables in the functional integral, plus parameter redefinitions, but a set of replacements, of actions and/or field variables and parameters. Because of this, we cannot write simple identities relating bare and renormalized generating functionals, or generating functionals before and after nonlinear changes of field variables. In this paper we investigate this issue and work out a general field-covariant approach to quantum field theory, which allows us to treat all perturbative changes of field variables, including the relation between bare and renormalized fields, as true changes of variables in the functional integral, under which the functionals Z and W=lnZ behave as scalars. We investigate the relation between composite fields and changes of field variables, and we show that, if J are the sources coupled to the elementary fields, all changes of field variables can be expressed as J-dependent redefinitions of the sources L coupled to the composite fields. We also work out the relation between the renormalization of variable-changes and the renormalization of composite fields. Using our transformation rules it is possible to derive the renormalization of a theory in a new variable frame from the renormalization in the old variable frame, without having to calculate it anew. We define several approaches, useful for different purposes, in particular a linear approach where all variable changes are described as linear source redefinitions. We include a number of explicit examples. (orig.)

  11. Chameleon field theories

    International Nuclear Information System (INIS)

    Khoury, Justin

    2013-01-01

    Chameleons are light scalar fields with remarkable properties. Through the interplay of self-interactions and coupling to matter, chameleon particles have a mass that depends on the ambient matter density. The manifestation of the fifth force mediated by chameleons therefore depends sensitively on their environment, which makes for a rich phenomenology. In this paper, we review two recent results on chameleon phenomenology. The first result a pair of no-go theorems limiting the cosmological impact of chameleons and their generalizations: (i) the range of the chameleon force at cosmological density today can be at most ∼Mpc; (ii) the conformal factor relating Einstein- and Jordan-frame scale factors is essentially constant over the last Hubble time. These theorems imply that chameleons have negligible effect on the linear growth of structure, and cannot account for the observed cosmic acceleration except as some form of dark energy. The second result pertains to the quantum stability of chameleon theories. We show how requiring that quantum corrections be small, so as to allow reliable predictions of fifth forces, leads to an upper bound of m −3 ) 1/3 eV for gravitational strength coupling, whereas fifth force experiments place a lower bound of m > 0.0042 eV. An improvement of less than a factor of 2 in the range of fifth force experiments could test all classical chameleon field theories whose quantum corrections are well-controlled and couple to matter with nearly gravitational strength regardless of the specific form of the chameleon potential. (paper)

  12. Preliminary study about occupational stress of physicians and nurses in pediatric and neonatal intensive care units: the balance between effort and reward Estudio preliminar sobre el estrés ocupacional de médicos y enfermeros en UTI pediátrica y neonatal: el equilibrio entre esfuerzo y recompensa Estudo preliminar sobre o estresse ocupacional de médicos e enfermeiros em UTI pediátrica e neonatal: o equilíbrio entre esforço e recompensa

    Directory of Open Access Journals (Sweden)

    Monalisa de Cássia Fogaça

    2010-02-01

    Full Text Available This study compared the balance between effort (E and reward (R among physicians and nurses working in pediatric (PED and neonatal (NEO Intensive Care Units. This descriptive cross-sectional study was carried out with 37 physicians and 20 nurses. The Effort-Reward Imbalance Questionnaire was used. Statistically significant differences were not found among physicians (p>0.05 or nurses from PED and NEO in relation to E and R (p>0.05. No statistically significant differences were found between physicians and nurses in PED in the several studied variables. Comparison between the professionals working in NEO revealed that physicians presented more over-commitment than nurses (p=0.01. The organizational setting of NEO proved to be more demanding for physicians, exacting a greater commitment to their work, while demands presented in both units seemed to be the same for nurses.El objetivo del estudio fue comparar el equilibrio entre esfuerzo (E y recompensa (R entre médicos de unidades de terapia intensiva pediátrica (PED y neonatal (NEO y entre enfermeros de las mismas unidades. Este es estudio transversal descriptivo con 37 médicos y 20 enfermeros. El cuestionario Effort-Reward Imbalance fue utilizado. No se encontraron diferencias estadísticas entre médicos de la PED y de la NEO en relación al E y R (p>0,05. De la misma forma, enfermeros de la PED y de la NEO no tuvieron diferencias estadísticas en relación al E y R (p>0,05. Comparando médicos con enfermeros de la PED, no fueron encontradas diferencias entre las variables estudiadas. En relación a la comparación hecha entre profesionales de la NEO, se encontró un mayor súper compromiso de médicos de que de enfermeros (p=0,01. El ambiente organizacional de la NEO se mostró más exigente para los médicos, determinando mayor compromiso con el trabajo, en cuanto que, para los enfermeros de ambas unidades, la demanda pareció ser la misma.O objetivo do estudo foi comparar o equil

  13. Field Audit Checklist Tool (FACT)

    Science.gov (United States)

    Download EPA's The Field Audit Checklist Tool (FACT). FACT is intended to help auditors perform field audits, to easily view monitoring plan, quality assurance and emissions data and provides access to data collected under MATS.

  14. Vacuum in intensive gauge fields

    International Nuclear Information System (INIS)

    Matinian, S.G.

    1977-12-01

    The behaviour of vacuum in a covariantly constant Yang-Mills field is considered. The expressions for the effective Lagrangian in an intensive field representing the asymptotic freedom of the theory are found

  15. Functional representations for quantized fields

    International Nuclear Information System (INIS)

    Jackiw, R.

    1988-01-01

    This paper provides information on Representing transformations in quantum theory bosonic quantum field theories: Schrodinger Picture; Represnting Transformations in Bosonic Quantum Field Theory; Two-Dimensional Conformal Transformations, Schrodinger picture representation, Fock space representation, Inequivalent Schrodinger picture representations; Discussion, Self-Dual and Other Models; Field Theory in de Sitter Space. Fermionic Quantum Field Theories: Schroedinger Picture; Schrodinger Picture Representation for Two-Dimensional; Conformal Transformations; Fock Space Dynamics in the Schrodinger Picture; Fock Space Evaluation of Anomalous Current and Conformal Commutators

  16. Geomagnetic Field During a Reversal

    Science.gov (United States)

    Heirtzler, J. R.

    2003-01-01

    It has frequently been suggested that only the geomagnetic dipole, rather than higher order poles, reverse during a geomagnetic field reversal. Under this assumption the geomagnetic field strength has been calculated for the surface of the Earth for various steps of the reversal process. Even without an eminent a reversal of the field, extrapolation of the present secular change (although problematic) shows that the field strength may become zero in some geographic areas within a few hundred years.

  17. TFTR magnetic field design analyses

    International Nuclear Information System (INIS)

    Davies, K.; Iwinski, E.; McWhirter, J.M.

    1975-11-01

    The three main magnetic field windings for the TFTR are the toroidal field (TF) windings, the ohmic heating (OH) winding, and the equilibrium field (EF) winding. The following information is provided for these windings: (1) descriptions, (2) functions, (3) magnetic designs, e.g., number and location of turns, (4) design methods, and (5) descriptions of resulting magnetic fields. This report does not deal with the thermal, mechanical support, or construction details of the windings

  18. Model of unified gauge fields

    International Nuclear Information System (INIS)

    Leite Lopes, J.

    1998-04-01

    In this work, we discuss the physical ideas which represents the basis for the unified gauge field model. Despite of the difficulties that we presently have for embodying in a natural manner muons and hadrons in that model, we have the feeling that we are on the way which seems to lead to the construction of a theory in which the Maxwell electromagnetic field and the Fermi weak interaction field are manifestations of a unique subjacent physical entity - the unified gauge fields. (author)

  19. Magnetic Field Topology in Jets

    Science.gov (United States)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  20. Quantization of fields with constraints

    Energy Technology Data Exchange (ETDEWEB)

    Gitman, D.M.; Tyutin, I.V.

    1990-01-01

    The quantization of singular field theories, in particular, gauge theories, is one of the key problems in quantum field theory. This book - which addresses the reader acquainted with the foundations of quantum field theory - provides a comprehensive analysis of this problem and techniques for its solution. The main topics are canonical and Lagrangian quantization and the path integral method. (orig.).

  1. High magnetic field MRI system

    International Nuclear Information System (INIS)

    Maeda, Hideaki; Urata, Masami; Satoh, Kozo

    1990-01-01

    A high field superconducting magnet, 4-5 T in central magnetic field, is required for magnetic resonance spectroscopic imaging (MRSI) on 31 P, essential nuclei for energy metabolism of human body. This paper reviews superconducting magnets for high field MRSI systems. Examples of the cross-sectional image and the spectrum of living animals are shown in the paper. (author)

  2. Field emission in RF cavities

    International Nuclear Information System (INIS)

    Bonin, B.

    1996-01-01

    Electron field emission limits the accelerating gradient in superconducting cavities. It is shown how and why it is an important problem. The phenomenology of field emission is then described, both in DC and RF regimes. Merits of a few plausible 'remedies' to field emission are discussed. (author)

  3. Estimation of Motion Vector Fields

    DEFF Research Database (Denmark)

    Larsen, Rasmus

    1993-01-01

    This paper presents an approach to the estimation of 2-D motion vector fields from time varying image sequences. We use a piecewise smooth model based on coupled vector/binary Markov random fields. We find the maximum a posteriori solution by simulated annealing. The algorithm generate sample...... fields by means of stochastic relaxation implemented via the Gibbs sampler....

  4. Electric fields in the magnetosphere

    International Nuclear Information System (INIS)

    Falthammar, C.G.

    1989-01-01

    Electric field measurements on the satellites GEOS-1, GEOS-2, ISEE-1, and Viking have extended the empirical knowledge of electric fields in space so as to include the outer regions of the magnetosphere. While the measurements confirm some of the theoretically expected properties of the electric fields, they also reveal unexpected features and a high degree of complexity and variability. The existence of a magnetospheric dawn-to-dusk electric field, as expected on the basis of extrapolation from low altitude measurements, is confirmed in an average sense. However, the actual field exhibits large spatial and temporal variations, including strong fields of inductive origin. At the magnetopause, the average (dawn-to-dusk directed) tangential electric field component is typically obscured by irregular fluctuations of larger amplitude. The magnetic-field aligned component of the electric field, which is of particular importance for ionosphere-magnetosphere coupling and for auroral acceleration, is even now very difficult to measure directly. However, the data from electric field measurements provide further support for the conclusion, based on a variety of evidence, that a non-vanishing magnetic-field aligned electric field exists in the auroral acceleration region

  5. Characteristic of Rings. Prime Fields

    Directory of Open Access Journals (Sweden)

    Schwarzweller Christoph

    2015-12-01

    Full Text Available The notion of the characteristic of rings and its basic properties are formalized [14], [39], [20]. Classification of prime fields in terms of isomorphisms with appropriate fields (ℚ or ℤ/p are presented. To facilitate reasonings within the field of rational numbers, values of numerators and denominators of basic operations over rationals are computed.

  6. Low field magnetic resonance imaging

    Science.gov (United States)

    Pines, Alexander; Sakellariou, Dimitrios; Meriles, Carlos A.; Trabesinger, Andreas H.

    2010-07-13

    A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.

  7. Quantization of the Radiation Field

    Indian Academy of Sciences (India)

    field,quantization,Lamb shift. Avinash Khare ... actions as well as for theories beyond like grand unified theories. Further, the same ... cules as well as condensed matter physics, not to men- tion their ... of an electromagnetic field by a moving electron, and of the reaction of this field on the electron have not yet been touched.".

  8. Introduction to string field theory

    International Nuclear Information System (INIS)

    Horowitz, G.T.

    1989-01-01

    A light cone gauge superstring field theory is constructed. The BRST approach is described discussing generalizations to yield gauge invariant free superstring field theory and interacting theory for superstrings. The interaction term is explicitly expressed in terms of first quantized oscillators. A purily cubic action for superstring field theory is also derived. (author)

  9. Fields on a random lattice

    International Nuclear Information System (INIS)

    Itzykson, C.

    1983-10-01

    We review the formulation of field theory and statistical mechanics on a Poissonian random lattice. Topics discussed include random geometry, the construction of field equations for arbitrary spin, the free field spectrum and the question of localization illustrated in the one dimensional case

  10. Matching tomographic IMRT fields with static photon fields

    International Nuclear Information System (INIS)

    Sethi, A.; Leybovich, L.; Dogan, N.; Emami, B.

    2001-01-01

    The matching of abutting radiation fields presents a challenging problem in radiation therapy. Due to sharp penumbra of linear accelerator beams, small (1-2 mm) errors in field positioning can lead to large (>30%) hot or cold spots in the abutment region. With head and neck immobilization devices (thermoplastic mask/aquaplast) an average setup error of 3 mm has been reported. Therefore hot or cold spots approaching 50% of the prescription dose may occur along the matchline. Although abutting radiation fields have been investigated for static fields, there is no reported study regarding matching of tomographic IMRT and static fields. Compared to static fields, the matching of tomographic IMRT fields with static fields is more complicated. Since IMRT and static fields are planned on separate treatment planning computers, the dose in the abutment region is not specified. In addition, commonly used techniques for matching fields, such as feathering of junctions, are not practical. We have developed a method that substantially reduces dose inhomogeneity in the abutment region. In this method, a 'buffer zone' around the matchline was created and was included as part of the target for both IMRT and static field plans. In both fields, a small dose gradient (≤3%/mm) in the buffer zone was created. In the IMRT plan, the buffer zone was divided into three sections with dose varying from 83% to 25% of prescription dose. The static field dose profile was modified using either a specially designed physical (hard) or a dynamic (soft) wedge. When these modified fields were matched, the combined dose in the abutment region varied by ≤10% in the presence of setup errors spanning 4 mm (±2 mm) when the hard wedge was used and 10 mm (±5 mm) with the soft wedge

  11. Titan's Gravitational Field

    Science.gov (United States)

    Schubert, G.; Anderson, J. D.

    2013-12-01

    Titan's gravitational field is inferred from an analysis of archived radio Doppler data for six Cassini flybys. The analysis considers each flyby separately in contrast to the approach of lumping all the data together in a massive inversion. In this way it is possible to gain an improved understanding of the character of each flyby and its usefulness in constraining the gravitational coefficient C22 . Though our analysis is not yet complete and our final determination of C22 could differ from the result we report here by 1 or 2 sigma, we find a best-fit value of C22 equal to (13.21 × 0.17) × 10-6, significantly larger than the value of 10.0 × 10-6 obtained from an inversion of the lumped Cassini data. We also find no determination of the tidal Love number k2. The larger value of C22 implies a moment of inertia factor equal to 0.3819 × 0.0020 and a less differentiated Titan than is suggested by the smaller value. The larger value of C22 is consistent with an undifferentiated model of the satellite. While it is not possible to rule out either value of C22 , we prefer the larger value because its derivation results from a more hands on analysis of the data that extracts the weak hydrostatic signal while revealing the effects of gravity anomalies and unmodeled spacecraft accelerations on each of the six flybys.

  12. The North Field Development

    International Nuclear Information System (INIS)

    1993-01-01

    The Qatar Europe LNG Company's activities include gas production, gathering, treatment, liquefaction, shipping and marketing of Liquefied Natural Gas (LNG) and by-products. The (LNG) project to be developed by the Company shall be initially capable of processing 1200 mmscfd of raw gas and associated quantities of condensate from the North Field. Hydrocarbons produced will be delivered to shore in the industrial area (Ras Laffan) via a sub sea pipeline system. Raw gas is used as a feedstock into the liquefaction plant which is initially capable of producing 6.1 Million Tonnes Per Annum (MTPA) of (LNG). The initial quantity of (LNG) will be exported from (Ras Laffan) loading terminal to a receiving terminal located on the North East coast of Italy via a dedicated fleet of (LNG) carriers. The whole project (Upstream, Downstream and Shipping) shall be executed on an integrated scheme basis under the the direct control of the Qatar Europe LNG Company and in accordance with the overall Master Schedule in order to ensure a delivery of first shipment of (LNG) in the 2 nd half of 1997. 3 figs

  13. Superstring field theory

    International Nuclear Information System (INIS)

    Green, M.B.

    1984-01-01

    Superstring field theories are formulated in terms of light-cone-gauge superfields that are functionals of string coordinates chi(sigma) and theta(sigma). The formalism used preserves only the manifest SU(4) symmetry that corresponds to rotations among six of the eight transverse directions. In type I theories, which have one ten-dimensional supersymmetry and describe both open and closed strings, there are five interaction terms of two basic kinds. One kind is a breaking or joining interaction, which is a string generalization of a cubic Yang-Mills coupling. It is relevant to both the three open-string vertex and the open-string to closed-string transition vertex. The other kind is an exchange or crossing-over interaction, which is a string generalization of a cubic gravitational coupling. All the interactions can be uniquely determined by requiring continuity of the coordinates chi(sigma) and theta(sigma) (which implies local conservation of the conjugate momenta) and by imposing the global supersymmetry algebra. Specific local operators are identified for each of the two kinds of interactions. In type II theories, which have two ten-dimensional supersymmetries and contain closed strings only, the entire interaction hamiltonian consists of a single cubic vertex. The higher-order contact terms of the N=8 supergravity theory that arises in the low-energy limit give an effective description of the exchange of massive string modes. (orig.)

  14. Digestible quantum field theory

    CERN Document Server

    Smilga, Andrei

    2017-01-01

    This book gives an intermediate level treatment of quantum field theory, appropriate to a reader with a first degree in physics and a working knowledge of special relativity and quantum mechanics. It aims to give the reader some understanding of what QFT is all about, without delving deep into actual calculations of Feynman diagrams or similar. The author serves up a seven‐course menu, which begins with a brief introductory Aperitif. This is followed by the Hors d'oeuvres, which set the scene with a broad survey of the Universe, its theoretical description, and how the ideas of QFT developed during the last century. In the next course, the Art of Cooking, the author recaps on some basic facts of analytical mechanics, relativity, quantum mechanics and also presents some nutritious “extras” in mathematics (group theory at the elementary level) and in physics (theory of scattering). After these preparations, the reader should have a good appetite for the Entrées ‐ the central par t of the book where the...

  15. Logarithmic conformal field theory

    Science.gov (United States)

    Gainutdinov, Azat; Ridout, David; Runkel, Ingo

    2013-12-01

    Conformal field theory (CFT) has proven to be one of the richest and deepest subjects of modern theoretical and mathematical physics research, especially as regards statistical mechanics and string theory. It has also stimulated an enormous amount of activity in mathematics, shaping and building bridges between seemingly disparate fields through the study of vertex operator algebras, a (partial) axiomatisation of a chiral CFT. One can add to this that the successes of CFT, particularly when applied to statistical lattice models, have also served as an inspiration for mathematicians to develop entirely new fields: the Schramm-Loewner evolution and Smirnov's discrete complex analysis being notable examples. When the energy operator fails to be diagonalisable on the quantum state space, the CFT is said to be logarithmic. Consequently, a logarithmic CFT is one whose quantum space of states is constructed from a collection of representations which includes reducible but indecomposable ones. This qualifier arises because of the consequence that certain correlation functions will possess logarithmic singularities, something that contrasts with the familiar case of power law singularities. While such logarithmic singularities and reducible representations were noted by Rozansky and Saleur in their study of the U (1|1) Wess-Zumino-Witten model in 1992, the link between the non-diagonalisability of the energy operator and logarithmic singularities in correlators is usually ascribed to Gurarie's 1993 article (his paper also contains the first usage of the term 'logarithmic conformal field theory'). The class of CFTs that were under control at this time was quite small. In particular, an enormous amount of work from the statistical mechanics and string theory communities had produced a fairly detailed understanding of the (so-called) rational CFTs. However, physicists from both camps were well aware that applications from many diverse fields required significantly more

  16. Rydberg atoms in strong fields

    International Nuclear Information System (INIS)

    Kleppner, D.; Tsimmerman, M.

    1985-01-01

    Experimental and theoretical achievements in studying Rydberg atoms in external fields are considered. Only static (or quasistatic) fields and ''one-electron'' atoms, i.e. atoms that are well described by one-electron states, are discussed. Mainly behaviour of alkali metal atoms in electric field is considered. The state of theoretical investigations for hydrogen atom in magnetic field is described, but experimental data for atoms of alkali metals are presented as an illustration. Results of the latest experimental and theoretical investigations into the structure of Rydberg atoms in strong fields are presented

  17. Quantum electrodynamics of strong fields

    International Nuclear Information System (INIS)

    Greiner, W.

    1983-01-01

    Quantum Electrodynamics of Strong Fields provides a broad survey of the theoretical and experimental work accomplished, presenting papers by a group of international researchers who have made significant contributions to this developing area. Exploring the quantum theory of strong fields, the volume focuses on the phase transition to a charged vacuum in strong electric fields. The contributors also discuss such related topics as QED at short distances, precision tests of QED, nonperturbative QCD and confinement, pion condensation, and strong gravitational fields In addition, the volume features a historical paper on the roots of quantum field theory in the history of quantum physics by noted researcher Friedrich Hund

  18. Urban Fields in the making

    DEFF Research Database (Denmark)

    Hovgesen, Henrik Harder; Nielsen, Thomas Alexander Sick

    cities and accentuates the concept of the ?urban field? suggested by John Friedmann (1978). The concept of ?urban field? suggest that mobility has been democratizised and increased to a level where several cities can be part of the same functionally integrated urban field. As a consequence...... the significance of the single urban centre and the city as an entity will change markedly. This paper aims to analyse the development towards urban travel- and commuter fields in Denmark. The question asked is to what degree urban fields are emerging? ? And what is the speed of this development....

  19. Studies in quantum field theory

    International Nuclear Information System (INIS)

    Bender, C.M.; Mandula, J.E.; Shrauner, J.E.

    1982-01-01

    Washington University is currently conducting research in many areas of high energy theoretical and mathematical physics. These areas include: strong-coupling approximation; classical solutions of non-Abelian gauge theories; mean-field approximation in quantum field theory; path integral and coherent state representations in quantum field theory; lattice gauge calculations; the nature of perturbation theory in large orders; quark condensation in QCD; chiral symmetry breaking; the l/N expansion in quantum field theory; effective potential and action in quantum field theories, including QCD

  20. Topics in quantum field theory

    International Nuclear Information System (INIS)

    Svaiter, N.F.

    2006-11-01

    This paper presents some important aspects on quantum field theory, covering the following aspects: the triumph and limitations of the quantum field theory; the field theory in curved spaces - Hawking and Unruh-Davies effects; the problem of divergent theory of the zero-point; the problem of the spinning detector and the Trocheries-Takeno vacuum; the field theory at finite temperature - symmetry breaking and phase transition; the problem of the summability of the perturbative series and the perturbative expansion for the strong coupling; quantized fields in presence of classical macroscopic structures; the Parisi-Wu stochastic quantization method

  1. Field reversal in mirror machines

    International Nuclear Information System (INIS)

    Pearlstein, L.D.; Anderson, D.V.; Boozer, A.H.

    1978-01-01

    This report discusses some of the physics issues anticipated in field-reversed mirrors. The effect of current cancellation due to electrons is described. An estimate is made of the required impurity level to maintain a field-reversed configuration. The SUPERLAYER code is used to simulate the high-β 2XIIB results, and favorable comparisons require inclusion of quasilinear RF turbulence. Impact of a quadrupole field on field-line closure and resonant transport is discussed. A simple self-consistent model of ion currents is presented. Conditions for stability of field-reversed configurations to E x B driven rotations are determined

  2. Field Model: An Object-Oriented Data Model for Fields

    Science.gov (United States)

    Moran, Patrick J.

    2001-01-01

    We present an extensible, object-oriented data model designed for field data entitled Field Model (FM). FM objects can represent a wide variety of fields, including fields of arbitrary dimension and node type. FM can also handle time-series data. FM achieves generality through carefully selected topological primitives and through an implementation that leverages the potential of templated C++. FM supports fields where the nodes values are paired with any cell type. Thus FM can represent data where the field nodes are paired with the vertices ("vertex-centered" data), fields where the nodes are paired with the D-dimensional cells in R(sup D) (often called "cell-centered" data), as well as fields where nodes are paired with edges or other cell types. FM is designed to effectively handle very large data sets; in particular FM employs a demand-driven evaluation strategy that works especially well with large field data. Finally, the interfaces developed for FM have the potential to effectively abstract field data based on adaptive meshes. We present initial results with a triangular adaptive grid in R(sup 2) and discuss how the same design abstractions would work equally well with other adaptive-grid variations, including meshes in R(sup 3).

  3. Neural fields theory and applications

    CERN Document Server

    Graben, Peter; Potthast, Roland; Wright, James

    2014-01-01

    With this book, the editors present the first comprehensive collection in neural field studies, authored by leading scientists in the field - among them are two of the founding-fathers of neural field theory. Up to now, research results in the field have been disseminated across a number of distinct journals from mathematics, computational neuroscience, biophysics, cognitive science and others. Starting with a tutorial for novices in neural field studies, the book comprises chapters on emergent patterns, their phase transitions and evolution, on stochastic approaches, cortical development, cognition, robotics and computation, large-scale numerical simulations, the coupling of neural fields to the electroencephalogram and phase transitions in anesthesia. The intended readership are students and scientists in applied mathematics, theoretical physics, theoretical biology, and computational neuroscience. Neural field theory and its applications have a long-standing tradition in the mathematical and computational ...

  4. Error field considerations for BPX

    International Nuclear Information System (INIS)

    LaHaye, R.J.

    1992-01-01

    Irregularities in the position of poloidal and/or toroidal field coils in tokamaks produce resonant toroidal asymmetries in the vacuum magnetic fields. Otherwise stable tokamak discharges become non-linearly unstable to disruptive locked modes when subjected to low level error fields. Because of the field errors, magnetic islands are produced which would not otherwise occur in tearing mode table configurations; a concomitant reduction of the total confinement can result. Poloidal and toroidal asymmetries arise in the heat flux to the divertor target. In this paper, the field errors from perturbed BPX coils are used in a field line tracing code of the BPX equilibrium to study these deleterious effects. Limits on coil irregularities for device design and fabrication are computed along with possible correcting coils for reducing such field errors

  5. Chameleons with Field Dependent Couplings

    CERN Document Server

    Brax, Philippe; Mota, David F; Nunes, Nelson J; Winther, Hans A

    2010-01-01

    Certain scalar-tensor theories exhibit the so-called chameleon mechanism, whereby observational signatures of scalar fields are hidden by a combination of self-interactions and interactions with ambient matter. Not all scalar-tensor theories exhibit such a chameleon mechanism, which has been originally found in models with inverse power run-away potentials and field independent couplings to matter. In this paper we investigate field-theories with field-dependent couplings and a power-law potential for the scalar field. We show that the theory indeed is a chameleon field theory. We find the thin-shell solution for a spherical body and investigate the consequences for E\\"ot-Wash experiments, fifth-force searches and Casimir force experiments. Requiring that the scalar-field evades gravitational tests, we find that the coupling is sensitive to a mass-scale which is of order of the Hubble scale today.

  6. Hyperbolic-symmetry vector fields.

    Science.gov (United States)

    Gao, Xu-Zhen; Pan, Yue; Cai, Meng-Qiang; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

    2015-12-14

    We present and construct a new kind of orthogonal coordinate system, hyperbolic coordinate system. We present and design a new kind of local linearly polarized vector fields, which is defined as the hyperbolic-symmetry vector fields because the points with the same polarization form a series of hyperbolae. We experimentally demonstrate the generation of such a kind of hyperbolic-symmetry vector optical fields. In particular, we also study the modified hyperbolic-symmetry vector optical fields with the twofold and fourfold symmetric states of polarization when introducing the mirror symmetry. The tight focusing behaviors of these vector fields are also investigated. In addition, we also fabricate micro-structures on the K9 glass surfaces by several tightly focused (modified) hyperbolic-symmetry vector fields patterns, which demonstrate that the simulated tightly focused fields are in good agreement with the fabricated micro-structures.

  7. ATLAS cavern magnetic field calculations

    International Nuclear Information System (INIS)

    Vorojtsov, S.B.; Vorozhtsov, A.S.; Butin, F.; Price, M.

    2000-01-01

    A new approach has been adopted in an attempt to produce a complete ATLAS cavern B-field map using a more precise methodological approach (variable magnetisation, depending on the external field) and the latest design taking into account of the structural elements. The basic idea was to produce a dedicated basic TOSCA model and then to insert a series of ferromagnetic structure elements to monitor the perturbative effect on the basic field map. Eventually, it was found: the bedplate field perturbation is an order of magnitude above the permissible level; manufacturing of the bedplates from nonmagnetic material or careful evaluation of their field contribution in the event reconstruction codes is required; the field value at the rack positions is higher than the permissible one; the final position of racks should be chosen taking into account the detailed magnetic field distribution

  8. The logarithmic conformal field theories

    International Nuclear Information System (INIS)

    Rahimi Tabar, M.R.; Aghamohammadi, A.; Khorrami, M.

    1997-01-01

    We study the correlation functions of logarithmic conformal field theories. First, assuming conformal invariance, we explicitly calculate two- and three-point functions. This calculation is done for the general case of more than one logarithmic field in a block, and more than one set of logarithmic fields. Then we show that one can regard the logarithmic field as a formal derivative of the ordinary field with respect to its conformal weight. This enables one to calculate any n-point function containing the logarithmic field in terms of ordinary n-point functions. Finally, we calculate the operator product expansion (OPE) coefficients of a logarithmic conformal field theory, and show that these can be obtained from the corresponding coefficients of ordinary conformal theory by a simple derivation. (orig.)

  9. The Swarm Initial Field Model for the 2014 Geomagnetic Field

    Science.gov (United States)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent; Finlay, Christopher C.; Beggan, Ciaran; Chulliat, Arnaud; Sabaka, Terence J.; Floberghagen, Rune; Friis-Christensen, Eigil; Haagmans, Roger

    2015-01-01

    Data from the first year of ESA's Swarm constellation mission are used to derive the Swarm Initial Field Model (SIFM), a new model of the Earth's magnetic field and its time variation. In addition to the conventional magnetic field observations provided by each of the three Swarm satellites, explicit advantage is taken of the constellation aspect by including east-west magnetic intensity gradient information from the lower satellite pair. Along-track differences in magnetic intensity provide further information concerning the north-south gradient. The SIFM static field shows excellent agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for east-west intensity differences between the lower satellite pair being only 0.12 nT.

  10. Field Science--the Nature and Utility of Scientific Fields.

    Science.gov (United States)

    Casadevall, Arturo; Fang, Ferric C

    2015-09-08

    Fields are the fundamental sociological units of science. Despite their importance, relatively little has been written about their emergence, composition, structure, and function in the scientific enterprise. This essay considers the nature of fields and their important role in maintaining information and providing normative standards for scientific work. We suggest that fields arise naturally as a consequence of increasing information and scientific specialization. New fields tend to emerge as research communities grow, which may reflect biologically determined optima for the size of human groups. The benefits of fields include the organization of scientists with similar interests into communities that collectively define the next important problems to pursue. In the discipline of microbiology, fields are often organized on the basis of phylogenetic differences between microorganisms being studied. Although fields are essential to the proper functioning of science, their emergence can restrict access by outsiders and sustain dogmas that hinder progress. We suggest mechanisms to improve the functioning of scientific fields and to promote interdisciplinary interaction between fields. Copyright © 2015 Casadevall and Fang.

  11. The gravity field and GGOS

    DEFF Research Database (Denmark)

    Forsberg, René; Sideris, M.G.; Shum, C.K.

    2005-01-01

    The gravity field of the earth is a natural element of the Global Geodetic Observing System (GGOS). Gravity field quantities are like spatial geodetic observations of potential very high accuracy, with measurements, currently at part-per-billion (ppb) accuracy, but gravity field quantities are also...... unique as they can be globally represented by harmonic functions (long-wavelength geopotential model primarily from satellite gravity field missions), or based on point sampling (airborne and in situ absolute and superconducting gravimetry). From a GGOS global perspective, one of the main challenges...... is to ensure the consistency of the global and regional geopotential and geoid models, and the temporal changes of the gravity field at large spatial scales. The International Gravity Field Service, an umbrella "level-2" IAG service (incorporating the International Gravity Bureau, International Geoid Service...

  12. Introduction to gauge field theory

    International Nuclear Information System (INIS)

    Bailin, D.; Love, A.

    1986-01-01

    This book provides a postgraduate level introduction to gauge field theory entirely from a path integral standpoint without any reliance on the more traditional method of canonical quantisation. The ideas are developed by quantising the self-interacting scalar field theory, and are then used to deal with all the gauge field theories relevant to particle physics, quantum electrodynamics, quantum chromodynamics, electroweak theory, grand unified theories, and field theories at non-zero temperature. The use of these theories to make precise experimental predictions requires the development of the renormalised theories. This book provides a knowledge of relativistic quantum mechanics, but not of quantum field theory. The topics covered form a foundation for a knowledge of modern relativistic quantum field theory, providing a comprehensive coverage with emphasis on the details of actual calculations rather than the phenomenology of the applications

  13. Gauge invariant fractional electromagnetic fields

    International Nuclear Information System (INIS)

    Lazo, Matheus Jatkoske

    2011-01-01

    Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.

  14. Gauge invariant fractional electromagnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Lazo, Matheus Jatkoske, E-mail: matheuslazo@furg.br [Instituto de Matematica, Estatistica e Fisica - FURG, Rio Grande, RS (Brazil)

    2011-09-26

    Fractional derivatives and integrations of non-integers orders was introduced more than three centuries ago but only recently gained more attention due to its application on nonlocal phenomenas. In this context, several formulations of fractional electromagnetic fields was proposed, but all these theories suffer from the absence of an effective fractional vector calculus, and in general are non-causal or spatially asymmetric. In order to deal with these difficulties, we propose a spatially symmetric and causal gauge invariant fractional electromagnetic field from a Lagrangian formulation. From our fractional Maxwell's fields arose a definition for the fractional gradient, divergent and curl operators. -- Highlights: → We propose a fractional Lagrangian formulation for fractional Maxwell's fields. → We obtain gauge invariant fractional electromagnetic fields. → Our generalized fractional Maxwell's field is spatially symmetrical. → We discuss the non-causality of the theory.

  15. Acoustic field modulation in regenerators

    Science.gov (United States)

    Hu, J. Y.; Wang, W.; Luo, E. C.; Chen, Y. Y.

    2016-12-01

    The regenerator is a key component that transfers energy between heat and work. The conversion efficiency is significantly influenced by the acoustic field in the regenerator. Much effort has been spent to quantitatively determine this influence, but few comprehensive experimental verifications have been performed because of difficulties in modulating and measuring the acoustic field. In this paper, a method requiring two compressors is introduced and theoretically investigated that achieves acoustic field modulation in the regenerator. One compressor outputs the acoustic power for the regenerator; the other acts as a phase shifter. A RC load dissipates the acoustic power out of both the regenerator and the latter compressor. The acoustic field can be modulated by adjusting the current in the two compressors and opening the RC load. The acoustic field is measured with pressure sensors instead of flow-field imaging equipment, thereby greatly simplifying the experiment.

  16. Local fields and their extensions

    CERN Document Server

    Fesenko, I B

    2002-01-01

    This book offers a modern presentation of local fields whose spectacular development was initiated almost one hundred years ago by K. Hensel. The volume consists of nine chapters divided into four parts: arithmetic properties of local fields, class field theory for various types of local fields and generalizations, explicit formulas for the Hilbert pairing, and Milnor K-groups of fields and of local fields. The first three parts essentially simplify, revise, and update the first edition. This second edition contains about sixty additional pages reflecting several aspects of the developments in local number theory in the last ten years. Exercises point to many other paths for exploration. The book is designed for graduate students and research mathematicians interested in local number theory and its applications in arithmetic algebraic geometry.

  17. Partially massless fields during inflation

    Science.gov (United States)

    Baumann, Daniel; Goon, Garrett; Lee, Hayden; Pimentel, Guilherme L.

    2018-04-01

    The representation theory of de Sitter space allows for a category of partially massless particles which have no flat space analog, but could have existed during inflation. We study the couplings of these exotic particles to inflationary perturbations and determine the resulting signatures in cosmological correlators. When inflationary perturbations interact through the exchange of these fields, their correlation functions inherit scalings that cannot be mimicked by extra massive fields. We discuss in detail the squeezed limit of the tensor-scalar-scalar bispectrum, and show that certain partially massless fields can violate the tensor consistency relation of single-field inflation. We also consider the collapsed limit of the scalar trispectrum, and find that the exchange of partially massless fields enhances its magnitude, while giving no contribution to the scalar bispectrum. These characteristic signatures provide clean detection channels for partially massless fields during inflation.

  18. Computers in field ion microscopy

    International Nuclear Information System (INIS)

    Suvorov, A.L.; Razinkova, T.L.; Sokolov, A.G.

    1980-01-01

    A review is presented of computer applications in field ion microscopy (FIM). The following topics are discussed in detail: (1) modeling field ion images in perfect crystals, (2) a general scheme of modeling, (3) modeling of the process of field evaporation, (4) crystal structure defects, (5) alloys, and (6) automation of FIM experiments and computer-assisted processing of real images. 146 references are given

  19. Mercury's magnetic field and interior

    International Nuclear Information System (INIS)

    Connerney, J.E.P.; Ness, N.F.

    1988-01-01

    The magnetic-field data collected on Mercury by the Mariner-10 spacecraft present substantial evidence for an intrinsic global magnetic field. However, studies of Mercury's thermal evolution show that it is most likely that the inner core region of Mercury solidified or froze early in the planet's history. Thus, the explanation of Mercury's magnetic field in the framework of the traditional planetary dynamo is less than certain

  20. In praise of quantum fields

    International Nuclear Information System (INIS)

    Shirkov, D.V.

    1989-08-01

    A comprehensive discussion of several topics vital for the structure of a modern Quantum Field Theory are discussed, namely: physical content of the notion of a Quantum Field; meaning of infinite renormalization; renormalizability as quantizability; the influence of several principles of quantum nature (quantizability, gauge dynamics, supersymmetry) on quantum fields dynamics; main trends of QFT evolution; present status of QFT and its frontier role in physics. (author). 15 refs, 1 fig

  1. The Emerging Field of Neuroepigenetics

    OpenAIRE

    Sweatt, J. David

    2013-01-01

    Over the past 25 years the broad field of epigenetics, and over the past decade in particular the emerging field of neuroepigenetics, have begun to have tremendous impact in the areas of learned behavior, neurotoxicology, CNS development, cognition, addiction, and psychopathology. However, epigenetics is such a new field that in most of these areas the impact is more in the category of fascinating implications as opposed to established facts. In this brief commentary I will attempt to address...

  2. Considerations on field problem structure

    International Nuclear Information System (INIS)

    Pavelescu, M.

    1977-01-01

    A survey of the three field problem types known today: equilibrium, eigen value and propagation problems is presented. The place occupied by neutron field in the nuclear reactor systems both statics and dynamics is shown. The special class of approximate solution method concerning the solving of field and boundary equations is analysed. The residual and variational method and the finite element method which presents a special interest are examined as well. (author)

  3. Quantum field theory of fluids.

    Science.gov (United States)

    Gripaios, Ben; Sutherland, Dave

    2015-02-20

    The quantum theory of fields is largely based on studying perturbations around noninteracting, or free, field theories, which correspond to a collection of quantum-mechanical harmonic oscillators. The quantum theory of an ordinary fluid is "freer", in the sense that the noninteracting theory also contains an infinite collection of quantum-mechanical free particles, corresponding to vortex modes. By computing a variety of correlation functions at tree and loop level, we give evidence that a quantum perfect fluid can be consistently formulated as a low-energy, effective field theory. We speculate that the quantum behavior is radically different from both classical fluids and quantum fields.

  4. Introduction to quantum field theory

    CERN Document Server

    Alvarez-Gaumé, Luís

    1994-01-01

    The purpose of this lecture is to review some elementary aspects of Quantum Field Theory. From the necessity to introduce quantum fields once quantum mechanics and special relativity are put together, to some of the basic practical computational tools in the subject, including the canonical quantization of simple field theories, the derivation of Feynman rules, computation of cross sections and decay rates, some introductory remarks on the treatment of unstable states and the possible realization of symmetries in a general field theory. The audience is required to have a working knowledge of quantum mechanics and special relativity and it would also be desirable to know the rudiments of relativistic quantum mechanics.

  5. Multiple fields in stochastic inflation

    Energy Technology Data Exchange (ETDEWEB)

    Assadullahi, Hooshyar [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom); Firouzjahi, Hassan [School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Noorbala, Mahdiyar [Department of Physics, University of Tehran,P.O. Box 14395-547, Tehran (Iran, Islamic Republic of); School of Astronomy, Institute for Research in Fundamental Sciences (IPM),P.O. Box 19395-5531, Tehran (Iran, Islamic Republic of); Vennin, Vincent; Wands, David [Institute of Cosmology & Gravitation, University of Portsmouth,Dennis Sciama Building, Burnaby Road, Portsmouth, PO1 3FX (United Kingdom)

    2016-06-24

    Stochastic effects in multi-field inflationary scenarios are investigated. A hierarchy of diffusion equations is derived, the solutions of which yield moments of the numbers of inflationary e-folds. Solving the resulting partial differential equations in multi-dimensional field space is more challenging than the single-field case. A few tractable examples are discussed, which show that the number of fields is, in general, a critical parameter. When more than two fields are present for instance, the probability to explore arbitrarily large-field regions of the potential, otherwise inaccessible to single-field dynamics, becomes non-zero. In some configurations, this gives rise to an infinite mean number of e-folds, regardless of the initial conditions. Another difference with respect to single-field scenarios is that multi-field stochastic effects can be large even at sub-Planckian energy. This opens interesting new possibilities for probing quantum effects in inflationary dynamics, since the moments of the numbers of e-folds can be used to calculate the distribution of primordial density perturbations in the stochastic-δN formalism.

  6. The Nonlinear Field Space Theory

    Energy Technology Data Exchange (ETDEWEB)

    Mielczarek, Jakub, E-mail: jakub.mielczarek@uj.edu.pl [Institute of Physics, Jagiellonian University, ul. Łojasiewicza 11, 30-348 Kraków (Poland); Trześniewski, Tomasz, E-mail: tbwbt@ift.uni.wroc.pl [Institute of Physics, Jagiellonian University, ul. Łojasiewicza 11, 30-348 Kraków (Poland); Institute for Theoretical Physics, University of Wrocław, pl. Borna 9, 50-204 Wrocław (Poland)

    2016-08-10

    In recent years the idea that not only the configuration space of particles, i.e. spacetime, but also the corresponding momentum space may have nontrivial geometry has attracted significant attention, especially in the context of quantum gravity. The aim of this letter is to extend this concept to the domain of field theories, by introducing field spaces (i.e. phase spaces of field values) that are not affine spaces. After discussing the motivation and general aspects of our approach we present a detailed analysis of the prototype (quantum) Nonlinear Field Space Theory of a scalar field on the Minkowski background. We show that the nonlinear structure of a field space leads to numerous interesting predictions, including: non-locality, generalization of the uncertainty relations, algebra deformations, constraining of the maximal occupation number, shifting of the vacuum energy and renormalization of the charge and speed of propagation of field excitations. Furthermore, a compact field space is a natural way to implement the “Principle of finiteness” of physical theories, which once motivated the Born–Infeld theory. Thus the presented framework has a variety of potential applications in the theories of fundamental interactions (e.g. quantum gravity), as well as in condensed matter physics (e.g. continuous spin chains), and can shed new light on the issue of divergences in quantum field theories.

  7. The Nonlinear Field Space Theory

    International Nuclear Information System (INIS)

    Mielczarek, Jakub; Trześniewski, Tomasz

    2016-01-01

    In recent years the idea that not only the configuration space of particles, i.e. spacetime, but also the corresponding momentum space may have nontrivial geometry has attracted significant attention, especially in the context of quantum gravity. The aim of this letter is to extend this concept to the domain of field theories, by introducing field spaces (i.e. phase spaces of field values) that are not affine spaces. After discussing the motivation and general aspects of our approach we present a detailed analysis of the prototype (quantum) Nonlinear Field Space Theory of a scalar field on the Minkowski background. We show that the nonlinear structure of a field space leads to numerous interesting predictions, including: non-locality, generalization of the uncertainty relations, algebra deformations, constraining of the maximal occupation number, shifting of the vacuum energy and renormalization of the charge and speed of propagation of field excitations. Furthermore, a compact field space is a natural way to implement the “Principle of finiteness” of physical theories, which once motivated the Born–Infeld theory. Thus the presented framework has a variety of potential applications in the theories of fundamental interactions (e.g. quantum gravity), as well as in condensed matter physics (e.g. continuous spin chains), and can shed new light on the issue of divergences in quantum field theories.

  8. Resonant helical fields in tokamaks

    International Nuclear Information System (INIS)

    Okano, V.

    1990-01-01

    Poincare maps of magnetic field lines of a toroidal helical system were made. The magnetic field is a linear superposition of the magnetic fields produced by a toroidal plasma in equilibrium and by external helical currents. Analytical expression for the Poincare maps was no obtained since the magnetic field do not have symmetry. In order to obtain the maps, the equation minus derivative of l vector times B vector = 0 was numerically integrated. In the Poincare maps, the principal and the secondary magnetic island were observed. (author)

  9. The Capacitive Magnetic Field Sensor

    Science.gov (United States)

    Zyatkov, D. O.; Yurchenko, A. V.; Balashov, V. B.; Yurchenko, V. I.

    2016-01-01

    The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented.

  10. K Basins Field Verification Program

    International Nuclear Information System (INIS)

    Booth, H.W.

    1994-01-01

    The Field Verification Program establishes a uniform and systematic process to ensure that technical information depicted on selected engineering drawings accurately reflects the actual existing physical configuration. This document defines the Field Verification Program necessary to perform the field walkdown and inspection process that identifies the physical configuration of the systems required to support the mission objectives of K Basins. This program is intended to provide an accurate accounting of the actual field configuration by documenting the as-found information on a controlled drawing

  11. Generalized field-transforming metamaterials

    International Nuclear Information System (INIS)

    Tretyakov, Sergei A; Nefedov, Igor S; Alitalo, Pekka

    2008-01-01

    In this paper, we introduce a generalized concept of field-transforming metamaterials, which perform field transformations defined as linear relations between the original and transformed fields. These artificial media change the fields in a prescribed fashion in the volume occupied by the medium. We show what electromagnetic properties of transforming medium are required. The coefficients of these linear functions can be arbitrary scalar functions of position and frequency, which makes the approach quite general and opens a possibility to realize various unusual devices.

  12. Field testing a soil site field guide for Allegheny hardwoods

    Science.gov (United States)

    S.B. Jones

    1991-01-01

    A site quality evaluation decision model, developed for Allegheny hardwoods on the non-glaciated Allegheny Plateau of Pennsylvania and New York, was field tested by International Paper (IP) foresters and the author, on sites within the region of derivation and on glaciated sites north and west of the Wisconsin drift line. Results from the field testing are presented...

  13. Towers of Function Fields over Non-prime Finite Fields

    DEFF Research Database (Denmark)

    Bassa, Alp; Beelen, Peter; Garcia, Arnaldo

    2015-01-01

    Over all non-prime finite fields, we construct some recursive towers of function fields with many rational places. Thus we obtain a substantial improvement on all known lower bounds for Ihara’s quantity A(ℓ), for ℓ = pn with p prime and n > 3 odd. We relate the explicit equations to Drinfeld modu...

  14. The Swarm Initial Field Model for the 2014 geomagnetic field

    DEFF Research Database (Denmark)

    Olsen, Nils; Hulot, Gauthier; Lesur, Vincent

    2015-01-01

    agreement (up to at least degree 60) with recent field models derived from CHAMP data, providing an initial validation of the quality of the Swarm magnetic measurements. Use of gradient data improves the determination of both the static field and its secular variation, with the mean misfit for East...

  15. Magnetic response to applied electrostatic field in external magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Adorno, T.C. [Universidade de Sao Paulo, Instituto de Fisica, Caixa Postal 66318, Sao Paulo, SP (Brazil); University of Florida, Department of Physics, Gainesville, FL (United States); Gitman, D.M. [Universidade de Sao Paulo, Instituto de Fisica, Caixa Postal 66318, Sao Paulo, SP (Brazil); Tomsk State University, Department of Physics, Tomsk (Russian Federation); Shabad, A.E. [P. N. Lebedev Physics Institute, Moscow (Russian Federation)

    2014-04-15

    We show, within QED and other possible nonlinear theories, that a static charge localized in a finite domain of space becomes a magnetic dipole, if it is placed in an external (constant and homogeneous) magnetic field in the vacuum. The magnetic moment is quadratic in the charge, depends on its size and is parallel to the external field, provided the charge distribution is at least cylindrically symmetric. This magneto-electric effect is a nonlinear response of the magnetized vacuum to an applied electrostatic field. Referring to the simple example of a spherically symmetric applied field, the nonlinearly induced current and its magnetic field are found explicitly throughout the space; the pattern of the lines of force is depicted, both inside and outside the charge, which resembles that of a standard solenoid of classical magnetostatics. (orig.)

  16. Superconductivity in Strong Magnetic Field (Greater Than Upper Critical Field)

    International Nuclear Information System (INIS)

    Tessema, G.X.; Gamble, B.K.; Skove, M.J.; Lacerda, A.H.; Mielke, C.H.

    1998-01-01

    The National High Magnetic Field Laboratory, funded by the National Science Foundation and other US federal Agencies, has in recent years built a wide range of magnetic fields, DC 25 to 35 Tesla, short pulse 50 - 60 Tesla, and quasi-continuous 60 Tesla. Future plans are to push the frontiers to 45 Tesla DC and 70 to 100 Tesla pulse. This user facility, is open for national and international users, and creates an excellent tool for materials research (metals, semiconductors, superconductors, biological systems ..., etc). Here we present results of a systematic study of the upper critical field of a novel superconducting material which is considered a promising candidate for the search for superconductivity beyond H c2 as proposed by several new theories. These theories predict that superconductors with low carrier density can reenter the superconducting phase beyond the conventional upper critical field H c2 . This negates the conventional thinking that superconductivity and magnetic fields are antagonistic

  17. Field observations and lessons learned

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Joh B [Los Alamos National Laboratory

    2010-01-01

    This presentation outlines observations and lessons learned from the Megaports program. It provides: (1) details of field and technical observations collected during LANL field activities at ports around the world and details of observations collected during radiation detections system testing at Los Alamos National Laboratory; (2) provides suggestions for improvement and efficiency; and (3) discusses possible program execution changes for more effective operations.

  18. Depletion field focusing in semiconductors

    NARCIS (Netherlands)

    Prins, M.W.J.; Gelder, Van A.P.

    1996-01-01

    We calculate the three-dimensional depletion field profile in a semiconductor, for a planar semiconductor material with a spatially varying potential upon the surface, and for a tip-shaped semiconductor with a constant surface potential. The nonuniform electric field gives rise to focusing or

  19. Simplified Representation of Vector Fields

    NARCIS (Netherlands)

    Telea, Alexandru; Wijk, Jarke J. van

    1999-01-01

    Vector field visualization remains a difficult task. Although many local and global visualization methods for vector fields such as flow data exist, they usually require extensive user experience on setting the visualization parameters in order to produce images communicating the desired insight. We

  20. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy; Bontemps, P.; Rikken, Geert L J A

    2011-01-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  1. Bell inequalities for random fields

    Energy Technology Data Exchange (ETDEWEB)

    Morgan, Peter [Physics Department, Yale University, CT 06520 (United States)

    2006-06-09

    The assumptions required for the derivation of Bell inequalities are not satisfied for random field models in which there are any thermal or quantum fluctuations, in contrast to the general satisfaction of the assumptions for classical two point particle models. Classical random field models that explicitly include the effects of quantum fluctuations on measurement are possible for experiments that violate Bell inequalities.

  2. Bell inequalities for random fields

    OpenAIRE

    Morgan, Peter

    2004-01-01

    The assumptions required for the derivation of Bell inequalities are not usually satisfied for random fields in which there are any thermal or quantum fluctuations, in contrast to the general satisfaction of the assumptions for classical two point particle models. Classical random field models that explicitly include the effects of quantum fluctuations on measurement are possible for experiments that violate Bell inequalities.

  3. Entendue invariance in speckle fields

    International Nuclear Information System (INIS)

    Medina, F.F.; Garcia-Sucerquia, J.; Henao, R.; Trivi, M.

    2000-04-01

    Experimental evidence is shown that confirms the Entendue invariance in speckle fields. Because of this condition, the coherence patch of the speckle field can be significantly greater than the mean size of the speckles, as is shown by double exposure speckle interferometry. (author)

  4. Low frequency electromagnetic field sensor

    International Nuclear Information System (INIS)

    Zhu Min; Zhou Yan; He Yicheng; Zheng Zhenxing; Liu Sunkun

    2000-01-01

    The measurement technique of low frequency electromagnetic field is reported. According to this principle, the authors have designed a sensor, which is used to measure the natural electromagnetic field, SLEMP and electromagnetic signals generated by some explosions. The frequency band of this sensor is from 0.08 Hz to 2 MHz

  5. Fast superconducting magnetic field switch

    Science.gov (United States)

    Goren, Yehuda; Mahale, Narayan K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.

  6. Electric field gradients in metals

    International Nuclear Information System (INIS)

    Schatz, G.

    1979-01-01

    A review of the recent works on electric field gradient in metals is given. The main emphasis is put on the temperature dependence of the electric field gradient in nonmagnetic metals. Some methods of investigation of this effect using nuclear probes are described. One of them is nuclear accoustic resonance method. (S.B.)

  7. Particles, fields, and now strings

    International Nuclear Information System (INIS)

    Weinberg, S.

    1986-01-01

    The author traces the history of the struggle between two views of the world: a world of particles or a world of fields. These positions were crystallised as quantum field theory and S-matrix theory and now by the reintroduction of string theories. (Auth.)

  8. Interdisciplinary in the Information Field

    DEFF Research Database (Denmark)

    Madsen, Dorte

    2012-01-01

    Interdisciplinarity and its implications for developing a conceptual framework for the Information Field is discussed, and Zhang & Benjamin’s (2007) paper Understanding Information Related Fields: A Conceptual Framework is examined. It is argued that the fundamental components of a framework must...

  9. Visualizing the Computational Intelligence Field

    NARCIS (Netherlands)

    L. Waltman (Ludo); J.H. van den Berg (Jan); U. Kaymak (Uzay); N.J.P. van Eck (Nees Jan)

    2006-01-01

    textabstractIn this paper, we visualize the structure and the evolution of the computational intelligence (CI) field. Based on our visualizations, we analyze the way in which the CI field is divided into several subfields. The visualizations provide insight into the characteristics of each subfield

  10. Field Lab on the Rocks.

    Science.gov (United States)

    King, David T., Jr.; Abbott-King, Janet P.

    1985-01-01

    Advocates taking students on field trips to highway roadcuts to illustrate various geological principles. Photographs of three roadcuts (with sample objectives and questions/answers for students to answer) are included. Also included are suggestions for preparation, safety, and activities during such field trips. (DH)

  11. Visualization of induced electric fields

    NARCIS (Netherlands)

    Deursen, van A.P.J.

    2005-01-01

    A cylindrical electrolytic tank between a set of Helmholtz coils provides a classroom demonstration of induced, nonconservative electric fields. The field strength is measured by a sensor consisting of a pair of tiny spheres immersed in the liquid. The sensor signal depends on position, frequency,

  12. Review of WAG Field Experience

    DEFF Research Database (Denmark)

    Christensen, Jes Reimer; Stenby, Erling Halfdan; Skauge, A.

    2001-01-01

    well spacing is in the order of 1000 m. For the fields reviewed, a common trend for the successful injections is an increased oil recovery in the range of 5 to 10% of the oil initially in place (OIIP). Very few field trials have been reported as unsuccessful, but operational problems are often noted...

  13. Fast superconducting magnetic field switch

    International Nuclear Information System (INIS)

    Goren, Y.; Mahale, N.K.

    1996-01-01

    The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles. 6 figs

  14. Mean-field lattice trees

    NARCIS (Netherlands)

    Borgs, C.; Chayes, J.T.; Hofstad, van der R.W.; Slade, G.

    1999-01-01

    We introduce a mean-field model of lattice trees based on embeddings into d of abstract trees having a critical Poisson offspring distribution. This model provides a combinatorial interpretation for the self-consistent mean-field model introduced previously by Derbez and Slade [9], and provides an

  15. NMR in pulsed magnetic field

    KAUST Repository

    Abou-Hamad, Edy

    2011-09-01

    Nuclear magnetic resonance (NMR) experiments in pulsed magnetic fields up to 30.4 T focused on 1H and 93Nb nuclei are reported. Here we discuss the advantage and limitation of pulsed field NMR and why this technique is able to become a promising research tool. © 2011 Elsevier Inc. All Rights Reserved.

  16. Strings, fields and critical phenomena

    International Nuclear Information System (INIS)

    Ambjoern, J.

    1987-07-01

    The connection between field theory and critical phenomena is reviewed. Emphasis is put on the use of Monte Carlo methods in the study of non-perturbative aspects of field theory. String theory is then described as a statistical theory of random surfaces and the critical behaviour is analyzed both by analytical and numerical methods. (orig.)

  17. Massive Yang-Mills fields

    NARCIS (Netherlands)

    Veltman, M.J.G.; Reiff, J.

    1969-01-01

    Two problems are studied in the paper: (i) the relation between Lagrangian and Feynman rules if the Lagrangian contains derivative couplings and/or vector meson fields and (ii) the behaviour of certain two closed loop diagrams in the perturbation theory of Yang-Mills fields. With respect to ( i ) .

  18. Quantum theory of noncommutative fields

    International Nuclear Information System (INIS)

    Carmona, J.M.; Cortes, J.L.; Gamboa, J.; Mendez, F.

    2003-01-01

    Generalizing the noncommutative harmonic oscillator construction, we propose a new extension of quantum field theory based on the concept of 'noncommutative fields'. Our description permits to break the usual particle-antiparticle degeneracy at the dispersion relation level and introduces naturally an ultraviolet and an infrared cutoff. Phenomenological bounds for these new energy scales are given. (author)

  19. Optimal field splitting for large intensity-modulated fields

    International Nuclear Information System (INIS)

    Kamath, Srijit; Sahni, Sartaj; Ranka, Sanjay; Li, Jonathan; Palta, Jatinder

    2004-01-01

    The multileaf travel range limitations on some linear accelerators require the splitting of a large intensity-modulated field into two or more adjacent abutting intensity-modulated subfields. The abutting subfields are then delivered as separate treatment fields. This workaround not only increases the treatment delivery time but it also increases the total monitor units (MU) delivered to the patient for a given prescribed dose. It is imperative that the cumulative intensity map of the subfields is exactly the same as the intensity map of the large field generated by the dose optimization algorithm, while satisfying hardware constraints of the delivery system. In this work, we describe field splitting algorithms that split a large intensity-modulated field into two or more intensity-modulated subfields with and without feathering, with optimal MU efficiency while satisfying the hardware constraints. Compared to a field splitting technique (without feathering) used in a commercial planning system, our field splitting algorithm (without feathering) shows a decrease in total MU of up to 26% on clinical cases and up to 63% on synthetic cases

  20. ) Ima Field: A Type Marginal Field-Challenges and Prospects

    International Nuclear Information System (INIS)

    Afolabi, T. J.

    2003-01-01

    The IMA Field is located in the south-eastern Niger Delta in approximately 30' of water. Discovered in 1972 by Japan Petroleum, commercial accumulation was not established until 1994 by the AMNI/Abacan Joint Venture, with the drilling of ima-3 well, which discovered the major reservoirs in the C and D sands. Recoverable Reserve of 48MMBO. Ten wells have been drilled on the IMA structure to date, with a cumulative production of 16 Million barrels of condensates.The IMA Field is a typical Niger Delta rollover anticlinal structure trending northeast southwest with a regional tilt to the northeast. The major trapping mechanism is the anticline.The sediments of IMA Field are Miocene Agbada Fm. They are deltaic deposits with high sand/shale ratio. The reservoirs are loosely compacted sandstones with porosity values ranging from 21% to 27% while permeability is generally measured in darcies.The development of IMA Field posed financial and logistical challenges since the partners had decided to fast track this process, and since neither had the resources to drill the development wells, assemble/install the crude processing and storage facilities; a mixture of debt financing and contractor financing arrangements were made.The prospects in IMA Field are to be found in early realisation of the limitations of a marginal field, particularly the management of cash flow. Workers and field development funding is financed by current production. Appraisal and exploration drilling within the same lease have required equity financing (participation)