INTELIGÊNCIA ARTIFICIAL COM ENFOQUE EM ALGORITMOS GENÉTICOS

Directory of Open Access Journals (Sweden)

Renata Luiza da Costa

2010-12-01

Full Text Available A palestra aqui proposta aborda as principais técnicas de Inteligência Artificial dando enfoque maior a técnica chamada Algoritmos Genéticos, a qual é aplicada a problemas de otimização. Tal palestra aborda os fundamentos teóricos do assunto e apresenta uma aplicação prática, desenvolvida usando a Linguagem de Programação Delphi, onde o problema da Dieta tem suas respostas factíveis encontradas a partir do uso de um Algoritmo Genético.

ESTIMACIÓN DE PARÁMETROS EN MODELOS NO LINEALES: ALGORITMOS Y APLICACIONES

Directory of Open Access Journals (Sweden)

Óscar Cornejo Zúñiga

Full Text Available En este artículo se muestran diferentes algoritmos para estimar parámetros en modelos no lineales. Se aplican primeramente a una base de datos de problemas clasificados difíciles. Posteriormente, se muestra el comportamiento de los algoritmos para el estudio de crecimiento de la merluza común en machos y hembras, anchoveta y sardina común ajustando un modelo de Von Bertalanffy. Se aplica el test de Cerrato para la comparación de crecimientos entre géneros para la merluza común. Los algoritmos se implementaron en ambiente MATLAB presentando un buen comportamiento en cuanto a tiempo CPU, número de iteraciones y exactitud de la solución encontrada respecto de valores certificados de los problemas de la base de datos.

ANÁLISIS Y COMPARACIÓN DE LOS ALGORITMOS DE CIFRADOS SIMÉTRICO EN PLATAFORMAS WINDIWS

OpenAIRE

Carrera Albán, Thruman Wladimir

2016-01-01

El objetivo principal que guía el diseño de cualquier algoritmo de cifrado debe ser la seguridad contra ataques no autorizados. Sin embargo, para todas las aplicaciones prácticas, el rendimiento y la velocidad también son preocupaciones importantes. Estas son las dos características principales que diferencian un algoritmo de cifrado de otro. Este documento proporciona la comparación de rendimiento entre dos de los algoritmos de cifrado más utilizados: AES (Rijndael) y Blowfish. La comparació...

Extensión del Algoritmo Evolutivo MOS con técnicas de Evolución Diferencial

OpenAIRE

Fernández Martín, Jaime

2008-01-01

Integración de un nuevo algoritmo de Evolución Diferencial en una librería de Algoritmos Evolutivos y su adaptación en forma de técnica para el algoritmo de hibridación MOS (Multiple Offspring Sampling). MOS es capaz de adaptarse a los problemas, premiando a las técnicas que mejores resutlados vayan obteniendo. Pruebas y estudios sobre los resultados obtenidos con esta nueva técnica.

Paralelización del Algoritmo Criptográfico GOST Empleando el Paradigma de Memoria Compartida

Directory of Open Access Journals (Sweden)

Marlis Fulgueira-Camilo

2015-06-01

Full Text Available El artículo refiere el proceso de paralelización del algoritmo criptográfico GOST. La investigación realizada persigue como objetivo, reducir el tiempo de ejecución del algoritmo. El estudio no se encuentra enfocado al análisis de fortaleza del algoritmo criptográfico, donde se hace énfasis es en el método empleado para disminuir el tiempo de ejecución de los procesos cifre y descifre. Para ello se realiza un diseño paralelo basado en la metodología de Ian Foster, el cual es aplicado a dos implementaciones usando técnicas como: OpenMP y CUDA. Las comparaciones realizadas teniendo en cuenta, tanto al algoritmo secuencial como las implementaciones paralelas, demuestran una significativa reducción de tiempo, sin importar la técnica empleada. El mejor resultado se logra empleando CUDA.

Aplicando un Algoritmo Genético para Balancear Carga Dinámicamente en Ambientes Distribuidos Orientados a Objetos (CORBA)

OpenAIRE

Fco. Javier Luna Rosas; Rene Tristán Ávila; J. de Jesús Martínez Pedroza

2003-01-01

Balancear Carga significa como distribuir procesos entre procesadores conectados por una red, para equilibrar la carga de trabajo entre ellos. Los algoritmos de planeación distribuida global pueden ser divididos en dos grandes grupos: algoritmos de balanceo de carga dinámica y algoritmos de balanceo de carga estática. Los algoritmos de balanceo de carga estática, también referenciados como planeación de tareas obtienen la localización de todos sus requerimientos antes de comenzar su ...

ANÁLISIS A LOS ALGORITMOS UTILIZADOS POR EL SOFTWARE PARA BI

Directory of Open Access Journals (Sweden)

CURTIS COOKE

2011-12-01

Full Text Available El propósito de este trabajo es examinar cuáles son los algoritmos que utilizan los paquetes de software más populares para BI. Una encuesta inicial informal muestra que los actuales paquetes de software de BI incluyen a la mayoría de algoritmos descritos en la literatura de los paquetes estadísticos tradicionales. Además, una de las principales diferencias entre el software para BI y los paquetes estadísticos tradicionales es que el primero tiene mejores características para los reportes.

Diseño e implementación de algoritmos de unificación y matching para términos comprimidos.

OpenAIRE

Ramos Garrido, Lander

2011-01-01

Las gramáticas incontextuales se pueden utilizar como herramienta para comprimir palabras o términos. Estas gramáticas pueden permitir en casos extremos comprimir hasta un factor exponencial. Sobre este tipo de compresiones existen diferentes algoritmos que se pueden implementar sin necesidad de descomprimir la palabra o término dados. En este PFC diseñamos nuevos algoritmos probabilísticos que se puedan aplicar a este tipo de compresiones. Estos algoritmos mejoran el coste de los algoritmos ...

Algoritmo de reconocimiento de patrones basado en codificación fisiológica en cerebro de primates.

OpenAIRE

CASTEL BAIXAULI, ALEJANDRO

2017-01-01

El cerebro humano y animal es capaz de reconocer una gran cantidad de patrones, como por ejemplo caras, utilizando un limitado número de neuronas y algoritmos de procesamiento [Chang et al 2017]. Sin embargo, los algoritmos de reconocimiento de patrones utilizados en la actualidad, incluso aquellos basados en redes neuronales, requieren un alto número de operaciones y capacidad de computo. El objetivo del presente trabajo final de grado es adaptar, desarrollar y validar un algoritmo de re...

Algunas relaciones entre algoritmos y resolución de problemas

Directory of Open Access Journals (Sweden)

Jaime Fonseca González

2012-04-01

Full Text Available Como parte del estudio realizado en la tesis de maestría “Uso de algoritmos en la resolución de problemas sobre isometrías del plano. Un estudio de caso”, se han identificado diversas formas en que se relacionan los algoritmos con la resolución de problemas, no sólo como procesos mecánicos, sino como fuente de información en el planteamiento de estrategias al resolver un problema, de modo que surgen algunas maneras en que se da esta relación, ejemplificando cada una de ellas con problemas cuyo objeto matemático central son las isometrías del plano.

Algoritmo de criptografia RSA: análise entre a segurança e velocidade

Directory of Open Access Journals (Sweden)

Rafael Santos Andrade

2012-12-01

Full Text Available O objetivo deste trabalho é abordar a relação existente entre a busca pela segurança de dados e a velocidade de codificação e decodificação do algoritmo de criptografia RSA, que utiliza um par de números inteiros como ‘chave’. Considerando o tamanho da chave como requisito de segurança, devido à dificuldade computacional de fatorar números inteiros extensos, simulamos estes processos, com o algoritmo implementado na linguagem de programação C, utilizando chaves aleatórias de 1024, 2048 e 4096 bits. Desta forma, observamos o tempo de processamento em função do tamanho das chaves, confrontando segurança e desempenho.Palavras-chave: criptografia; algoritmo RSA; segurança; desempenho.

Algoritmo para el cálculo de la velocidad media óptima en una ruta (ASGA

Directory of Open Access Journals (Sweden)

V. Corcoba Magaña

2014-10-01

Full Text Available Resumen: En este trabajo se propone un algoritmo para obtener la velocidad media óptima para ahorrar combustible y mejorar la seguridad. El algoritmo propuesto se basa en los algoritmos genéticos. El algoritmo emplea información sobre el entorno, la carretera y el vehículo para obtener la velocidad media que minimice el consumo de combustible sin incrementar drásticamente la duración del trayecto. Además, el algoritmo propuesto mejora la seguridad ya que adecua la velocidad a las condiciones de la vía. La información sobre el entorno se obtiene de servicios web y la información sobre el vehículo se obtiene a través del puerto OBD2. El algoritmo es validado en situaciones reales con incidentes de tráfico y sin ellos. Por otra parte, se analiza el impacto de la velocidad media y los incidentes de tráfico en las aceleraciones y su influencia en el consumo de combustible. Abstract: This paper proposes an algorithm for obtaining the optimal average speed to save fuel and improve safety. The proposed algorithm is based on genetic algorithms. The algorithm uses information about the environment, the road and the vehicle for obtaining the optimal average speed which it minimizes fuel consumption without dramatically increasing the travel time. Moreover, the proposed algorithm improves safety adapting vehicle speed to road conditions. The environment information is obtained from web services and vehicle information is obtained through the OBD2 port. The algorithm is validated in situations with and without incidents. In addition, we analyze the impact of the average speed and acceleration incidents and their impact on fuel consumption. Palabras clave: Conducción eficiente, Sistemas de ayuda a la conducción, Algoritmos Genéticos, Android, Sistemas Inteligentes de Transporte., Keywords: Eco-driving, Advanced Driver Assistance Systems, Genetic Algorithms, Android, Intelligent Transport System.

Algoritmo de tipo búsqueda tabú para un problema de programación de horarios universitarios vespertinos

Directory of Open Access Journals (Sweden)

Cristian David Oliva San Martín

2013-07-01

Full Text Available En este estudio se presenta un modelo de programación no lineal en variables enteras para un problema de programación de horarios universitarios vespertinos y se propone un algoritmo para su solución. El problema consiste en programar asignaturas en un horizonte de planificación considerando profesores, aulas, alumnos, días y un conjunto de restricciones, buscando minimizar la penalidad de no satisfacer los requerimientos de profesores, el número de cambios de sala y el número de periodos libres entre cursos. Se propone un modelo matemático y una implementación de un algoritmo de tipo búsqueda tabú. Para evaluar la efectividad del algoritmo se utilizaron casos de prueba con datos reales del Instituto IPEGE (Chile, en los que el algoritmo es capaz de obtener soluciones factibles en un tiempo razonable. Los parámetros de dicho algoritmo fueron calibrados con los casos de prueba, para posteriormente evaluar su desempeño. Se muestra que este obtuvo mejores soluciones que el método manual.

Implementación del Algoritmo Sünter-Clare en un Convertidor Matricial 3x3

Directory of Open Access Journals (Sweden)

Eliher A. Ortiz Colín

2017-10-01

time as in the variable speed wind generation system. The experimental control setup is comprised of a field programmable gate array board, a digital signal processor and a graphics interface board. Palabras clave: Convertidor matricial, algoritmo de modulación Sünter-Clare, distorsión total armónica, Keywords: Matrix converter, Sünter-Clare modulation algorithm, Total Harmonic Distortion

Algoritmo para el cálculo de cargas de trabajo

Directory of Open Access Journals (Sweden)

Mauricio Becerra Fernández

2016-04-01

Full Text Available Este artículo presenta el desarrollo un algoritmo para el cálculo de cargas de trabajo, soportado en el análisis de estudios similares y la teoría del estudio de métodos y tiempos. El algoritmo se propone como un elemento de soporte para el análisis del nivel trabajo asignado a un cargo específico o a un grupo de trabajadores en un área determinada, ya sea en la industria de manufactura o de servicios, lo que permita nivelar el volumen de trabajo asignado mediante la definición de diversas alternativas que promuevan el aumento de la productividad, favorezcan la mejora en el clima y las condiciones laborales.

Algoritmos rápidos de detecção de colisão broad phase utilizando KD-trees

OpenAIRE

Rocha, Rafael de Sousa

2010-01-01

Neste trabalho, três novos algoritmos rápidos de detecção de colisão broad phase, os quais utilizam a estrutura de particionamento espacial conhecida como KD-Tree, foram pro- postos e implementados: KDTreeSpace, DynamicKDTreeSpace e StatelessKDTreeSpace. Estes algoritmos foram integrados à biblioteca Open Dynamics Engine (ODE), responsável pelo cálculo do movimento dos objetos dinâmicos, como possíveis alternativas aos algoritmos de broad phase disponíveis nesta biblioteca. Os algori...

Algoritmos de aproximação para problemas de empacotamento em faixa com restrições de descarregamento

OpenAIRE

Jefferson Luiz Moisés da Silveira

2011-01-01

Resumo: Neste trabalho estudamos problemas de empacotamento com restrições de descarregamento considerados NP-difíceis. Estes problemas possuem aplicações nas áreas de logística e roteamento. Assumindo a hipótese de que P ? NP, sabemos que não existem algoritmos eficientes para resolver tais problemas. Uma das abordagens consideradas para tratar tais problemas é a de algoritmos de aproximação, que são algoritmos eficientes (complexidade de tempo polinomial) e que geram soluções com garantia d...

CB-SMoT+: UNA EXTENSIÓN AL ALGORITMO CB-SMoT

Directory of Open Access Journals (Sweden)

FRANCISCO MORENO

2012-12-01

Full Text Available Una trayectoria es un registro de la evoluciónde la posición de un objeto móvil. Por ejemplo,un vehículo que se mueve en el espacio durante unintervalo de tiempo. Una trayectoria se representamediante una secuencia de observaciones que indicanla posición y el tiempo en el que fue tomada cadaobservación. CB-SMoT es un algoritmo que identificalas partes de una trayectoria durante las cuales elobjeto mantuvo una velocidad promedio por debajode un límite dado. En este artículo se propone unaextensión para dicho algoritmo que permite identificarlas partes de una trayectoria durante las cualesel objeto mantuvo una velocidad promedio entre observacionespor debajo de un límite dado. Esto posibilitala identificación, por ejemplo, de violacionesa un límite de velocidad que no son advertidas porel algoritmo original. Para el estudio se usó el sistemade gestión de bases de datos PostgreSQL y losalgoritmos se implementaron en su lenguaje de programación,llamado PL/pgSQL. Además, se hicieronexperimentos con 100 trayectorias de vehículos conel propósito de mostrar la utilidad y la viabilidad de lapropuesta.

Algoritmos evolutivos aplicados al diseño inteligente de parques eólicos

OpenAIRE

Bilbao, Martín; Alba, Enrique

2011-01-01

En este documento se muestran dos tipos de algoritmos metaheurísticos aplicados al diseño inteligente de un parque eólico, la idea básica es utilizar CHC y algoritmos genéticos para obtener una buena configuración de molinos dentro del parque de tal manera que maximicen la energía total producida y minimicen la cantidad de molinos utilizados. En este trabajo analizaremos dos casos de estudios con una distribución real de vientos de la patagonia argentina, un terreno irregular con restriccione...

Algoritmos de compresión paralela

OpenAIRE

Anderson, Alfredo; Dirazar, Delio

1997-01-01

El objetivo planteado inicialmente fue analizar la viabilidad de distribuir un compresor de datos en una red de procesadores. Además de elegir el algoritmo a implementar y definir alternativas de distribución debíamos seleccionar un lenguaje y un sistema operativo que soporten las herramientas de multiprocesamiento necesarias para la implementación de las versiones distribuidas. Nuestro primer paso fué realizar la implementación de dos compresores de datos basados en el mismo algortimo,...

Algoritmo genético e espectroscopia no infravermelho - algumas aplicações na indústria cosmética

OpenAIRE

Marcos Coelho Amendola

2007-01-01

Este trabalho discute o desenvolvimento de um algoritmo genético escrito em linguagem VBA para Excel e suas aplicações. O algoritmo elaborado foi utilizado em combinação com a técnica de FTIR-ATR para o desenvolvimento de metodologias aplicáveis na indústria cosmética e de saneantes, tais como a quantificação de surfactantes e bactericidas. Algumas modificações introduzidas no algoritmo foram estudadas através das aplicações selecionadas, destacando-se a introdução de técnicas de paralelismo ...

Análise de desempenho de algoritmos evolutivos no domínio do futebol de robôs

OpenAIRE

Eduardo Sacogne Fraccaroli

2010-01-01

Muitos problemas de otimização em ambientes multiagentes utilizam os algoritmos evolutivos para encontrar as melhores soluções. Uma das abordagens mais utilizadas consiste na aplicação de um algoritmo genético, como alternativa aos métodos tradicionais, para definir as ações dos jogadores em um time de futebol de robôs. Entretanto, conforme relatado na literatura, há inúmeras possibilidades e formas de se aplicar um algoritmo genético no domínio do futebol de robôs. Assim sendo, neste trabalh...

UN ALGORITMO SAEM PARA EL PROBLEMA DE COMPLETACIÓN DE MATRICES // A SAEM ALGORITHM FOR MATRIX COMPLETION PROBLEMS

Directory of Open Access Journals (Sweden)

Anaís Frangeline Acuña Sosa

2015-06-01

Full Text Available In this work we dealt with matrix completion problem. This problem arises in different fields, for example, systems and control theory, image processing and collaborative filtering. Given a probabilistic matrix factorization model, we present an approach based on Bayesian statistics and a stochastic expectation maximization algorithm to retrieve an array of data from a sample of its inputs. The proposed method does not require regularization parameters and estimates the rank of the matrix, in contrast to the BPMF method. Our results show that the proposed method outperforms to an augmented lagrangian algorithm and the BPMF method in its ability to find the rank of the matrix and in efficiency respectively. // RESUMEN En este trabajo estudiamos el problema de completación de matrices. Este problema se presenta en diversas áreas como la teoría de sistemas y control, procesamiento de imágenes y filtrado colaborativo. Considerando un modelo de factorización probabilística de matrices, establecemos una propuesta basada en estadística Bayesiana y un algoritmo EM estocástico para recubrir una matriz de datos a partir de una muestras de sus entradas. El método propuesto no requiere de parámetros de regularización y da un estimado del rango de la matriz, en contraste con el método BPMF. Los resultados muestran que el algoritmo propuesto da mejores estimados del rango de la matriz en comparación con un algoritmo basado en lagrangeanos aumentados y es más eficiente que el método BPMF.

IMPLEMENTACIÓN EN HARDWARE DE UN SVPWM EN UN SOFT-CORE NIOS II PARTE II: ALGORITMO DEL SVPWM

Directory of Open Access Journals (Sweden)

Jorge Rivera

2009-01-01

Full Text Available En este trabajo se presentan los detalles de la moduclación por ancho de pulso en el espacio vectorial (SVPWM por sus siglas en inglés. Primero se plantea el escenario en donde es más usado este algoritmo, es decir, en el control de motores eléctricos trifásicos. Se explica que el algoritmo del SVPWM sirve para manejar los inversores, además se indica en qué marco de referencia deben estar las acciones de control que el algortimo del SVPWM acepta, para finalmente presentar el algoritmo de una manera clara y concisa.

Algoritmos y gramáticas : un capitulo apasionante de la teoría cognitiva

OpenAIRE

Pérez Alcázar, Jesús Hernando

2012-01-01

DOS GRANDES PROBLEMASUno de los grandes pioneros de la teoría cognitiva es el profesor norteamericano Noam Chomsky. En este ensayo presentaremos algunos de sus muy numerosos aportes al desarrollo de esta nueva teoría, limitando la atención a las relaciones entre gramaticas y algoritmos. Una manera muy sugestiva de abordar las relaciones entre los algoritmos matemáticos y las gramáticas de la teoría lingüística, la ofrece el propio Noam Chomsky en su importante trabajo "El conocimiento del len...

Paralelización del Algoritmo Expectación–Maximización Utilizando OpenCL

Directory of Open Access Journals (Sweden)

Ernesto Insua-Suárez

2014-12-01

Full Text Available Actualmente, las organizaciones y empresas almacenan grandes volúmenes de datos para lograr sus propósitos. Una de las variantes para obtener información valiosa consiste en el empleo de la Minería de datos. Dentro de esta, existen diferentes tareas, una de ellas es el agrupamiento. En esta tarea los datos se agrupan según sus semejanzas entre si y diferencias con elementos de otros grupos. Dentro de los algoritmos que realizan estos agrupamientos se encuentra Expectación-Maximización, el cual presenta elevados tiempos de ejecución en la medida que aumenta el tamaño de los datos. En el presente artículo se discute acerca de la paralelización del algoritmo, utilizando técnicas de programación paralela. El diseño del algoritmo propuesto se basa en el uso de las tarjetas de procesamiento gráfico, GPU. OpenCL, lenguaje empleado para la programación en arquitecturas híbridas, permite aprovechar las arquitecturas de hardware disponibles, con lo que se logra disminuir el tiempo de ejecución de la implementación realizada. La razón principal por lo cual es posible mejorar este tiempo se debe a la cantidad de procesos paralelos que se pueden lanzar en hilos de procesamientos independientes. Para el logro de los resultados descritos se integran conocimientos del campo de la Minería de datos y la Computación Paralela y Distribuida. Como parte de esta investigación, se realizó una implementación del algoritmo utilizando las bibliotecas de OpenCL, para disminuir su tiempo de ejecución. La implementación logra disminuir en un 82% la implementación secuencial. Esto significa que el algoritmo paralelo se ejecuta 5,5 veces más rápido que su correspondiente implementación secuencial.

Algoritmos de previsión a corto plazo en base a radar meteorológico

OpenAIRE

Campeny Mora, Mercè

2008-01-01

Las consecuencias de las inundaciones suelen ser devastadoras. Los sistemas de protección tradicionales se complementan cada vez más con sistemas de prevención y alerta de inundaciones. En este sentido, el radar meteorológico y los algoritmos de previsión adquieren una importancia clave. El objetivo de la tesina es la mejora de los algoritmos de previsión en base a radar meteorológico a partir del estudio de distintos factores que intervienen.

El problema del agente viajero: un algoritmo determinístico usando búsqueda tabú

Directory of Open Access Journals (Sweden)

Erasmo López

2014-04-01

Full Text Available Se implementa un algoritmo correspondiente al método Búsqueda Tabú, llamado EraDeterminístico, experimentado con el algoritmo básico que explora el espacio de búsqueda e incorporando la diversificación como estrategia para explorar nuevas regiones. El algoritmo se desarrolla en el ambiente de programación Visual Basic 6.0 y la implementación se orienta a encontrar soluciones cercanas a la óptima del problema NP−Completo del Agente Viajero Simétrico (AVS. Para probar la funcionalidad, el modelo se compara con algunas instancias de la Travel Salesman Problem Li- brary (TSPLIB, algunas instancias aleatorias y se aplica a tres situaciones reales. Finalmente, se presenta una sección donde se exponen recomendaciones y conclusiones, las cuales orientan posibles desarrollos futuros de ésta teoría y donde se pone en evidencian las bondades y la eficiencia de la implementación.

Software para la enseñanza-aprendizaje de algoritmos estructurados

Directory of Open Access Journals (Sweden)

Arellano Pimentel, J. Jesús

2012-12-01

Full Text Available Actualmente existen diversas herramientas de software que sirven como recurso didáctico en la enseñanza-aprendizaje de algoritmos estructurados a nivel superior. Sin embargo, la gran mayoría solo hace énfasis en el diseño y prueba de los algoritmos. En el presente trabajo se propone un nuevo software, con base en la heurística de resolución de problemas de Polya, que da soporte a las fases de análisis y planteamiento del problema, además del diseño y traza completa de la prueba. Se realiza un análisis cualitativo entre el software propuesto y otras tres herramientas ampliamente utilizadas a nivel superior. La estructura y funcionalidad del software propuesto contribuye a que el estudiante adquiera, practique y ejercite la capacidad de resolver problemas de forma metódica a través de soluciones algorítmicas estructuradas.

Algoritmo incremental de agrupamiento con traslape para el procesamiento de grandes colecciones de datos (Overlapping clustering incremental algorithm for large data collections processing

Directory of Open Access Journals (Sweden)

Lázaro Janier González-Soler

2015-12-01

Full Text Available Spanish abstract Existen diversos problemas en el Reconocimiento de Patrones y en la Minería de Datos que, por su naturaleza, consideran que los objetos pueden pertenecer a más de una clase o grupo. DClustR es un algoritmo dinámico de agrupamiento con traslape que ha mostrado, en tareas de agrupamiento de documentos, el mejor balance entre calidad de los grupos y eficiencia entre los algoritmos dinámicos de agrupamiento con traslape reportados en la literatura. A pesar de obtener buenos resultados, DClustR puede ser poco útil en aplicaciones que trabajen con grandes colecciones de documentos, debido a que tiene una complejidad computacional y a la cantidad de memoria que utiliza para el procesamiento de las colecciones. En este trabajo se presenta una versión paralela basada en GPU del algoritmo DClustR, llamada CUDA-DClus, para mejorar la eficiencia de DClustR en aplicaciones que lidien con largas colecciones de documentos. Los experimentos fueron realizados sobre varias colecciones estándares de documentos y en ellos se muestra el buen rendimiento de CUDA-DClus en términos de eficiencia y consumo de memoria. English abstract There are several problems in Pattern Recognition and Data Mining that, by its inherent nature, consider that the objects can belong to more than a class or cluster. DClustR is a dynamic overlapping clustering algorithm that has shown, in document clustering tasks, the best trade-off between cluster’s quality and efficiency among existing dynamic overlapping clustering algorithms. However, DClustR could be less useful when working in applications that deal with large data collections, due to its computational complexity and memory demanded for processing them. In this paper, a GPU-based parallel algorithm of DClustR, named CUDA-DClus is suggested to enhance DClustR efficiency in applications dealing with large data collections. The experimental phase conducted over various standard data collections showed that

Diseño óptimo de un sistema de distribución de agua (SDA aplicando el algoritmo Simulated Annealing (SA

Directory of Open Access Journals (Sweden)

Maikel Méndez-Morales

2014-09-01

Full Text Available En este artículo se presenta la aplicación del algoritmo Simulated Annealing (SA en el diseño óptimo de un sistema de distribución de agua (SDA. El SA es un algoritmo metaheurístico de búsqueda, basado en una analogía entre el proceso de recocido en metales (proceso controlado de enfriamiento de un cuerpo y la solución de problemas de optimización combinatorios. El algoritmo SA, junto con diversos modelos matemáticos, ha sido utilizado exitosamente en el óptimo diseño de SDA. Como caso de estudio se utilizó el SDA a escala real de la comunidad de Marsella, en San Carlos, Costa Rica. El algoritmo SA fue implementado mediante el conocido modelo EPANET, a través de la extensión WaterNetGen. Se compararon tres diferentes variaciones automatizadas del algoritmo SA con el diseño manual del SDA Marsella llevado a cabo a prueba y error, utilizando únicamente costos unitarios de tuberías. Los resultados muestran que los tres esquemas automatizados del SA arrojaron costos unitarios por debajo del 0.49 como fracción, respecto al costo original del esquema de diseño ejecutado a prueba y error. Esto demuestra que el algoritmo SA es capaz de optimizar problemas combinatorios ligados al diseño de mínimo costo de los sistemas de distribución de agua a escala real.

Comprensión de los algoritmos de las operaciones aritméticas en estudiantes de Magisterio

OpenAIRE

Salinas, María Jesús

2003-01-01

Partiendo de la creencia de que las matemáticas escolares deben formar parte del componente del conocimiento sobre las matemáticas del futuro maestro, se hizo un estudio sobre dos campos sistema de numeración decimal y algoritmos usuales de las operaciones aritméticas. En esta comunicación nos centramos solamente en el campo correspondiente a los algoritmos. Presentaremos los resultados generales y un análisis de las respuestas de 82 protocolos de una muestra de 467 sujetos correspondiente al...

Análisis Comparativo de Algoritmos de Minería de Subgrafos Frecuentes

Directory of Open Access Journals (Sweden)

Santiago Bianco

2016-06-01

Full Text Available Gracias a las posibilidades que ofrecen a la hora de representar información y la abstracción conceptual que permiten manejar, los grafos son ampliamente utilizados en investigaciones relacionadas con la informática. A medida que se fueron incrementando las aplicaciones de estas estructuras, la complejidad de los elementos a representar y el volumen de información manejado, aparece la necesidad de utilizar procesos eficientes para extraer información o patrones ocultos en esa gran masa de datos, por lo que se comienza a aplicar la minería de grafos. Dentro las técnicas de minería de grafos se encuentra la búsqueda de subgrafos frecuentes, utilizada para reconocer subestructuras comunes entre un conjunto de grafos. En los últimos años se han llevado a cabo varias investigaciones que resuelven este problema, generando algoritmos diversos aplicando distintos enfoques, entre los cuales se encuentran el FSG, FFSM, gSpan y GASTON. El objetivo de este artículo es analizar el comportamiento de estos algoritmos a través de distintos experimentos diseñados para identificar si existe un algoritmo superior al resto y, en caso de que no lo haya, poder definir en qué escenarios es más recomendable la elección de cada uno.

ASIGNACIÓN DE SUPERVISORES FORESTALES: RESOLUCIÓN MEDIANTE UN ALGORITMO TABU SEARCH ASSIGNMENT OF FOREST SUPERVISORS: RESOLUTION BY MEANS OF A TABU SEARCH ALGORITHM

Directory of Open Access Journals (Sweden)

Lorena Pradenas Rojas

2008-12-01

Full Text Available En este estudio se presenta un modelo matemático para un problema genérico de asignación de personal. Se implementa y evalúa un procedimiento de solución mediante la metaheurística Tabu Search. El algoritmo propuesto es usado para resolver un caso real de asignación de supervisores forestales. Los resultados muestran que el algoritmo desarrollado es eficiente en la resolución de este tipo de problema y tiene un amplio rango de aplicación para otras situaciones reales.This study presents a mathematical model for a generic problem of staff allocation. A solution is implemented and evaluated by means of the Tabu Search metaheuristic. The proposed algorithm is used to solve a real case of forestry supervisors' allocation. The results show that the developed algorithm is efficient solving this kind of problems and that it has a wide range of application for other real situations.

Diseño e integración de algoritmos criptográficos en sistemas empotrados sobre FPGA

Directory of Open Access Journals (Sweden)

Alejandro Cabrera Aldaya

2013-10-01

Full Text Available En este trabajo se integran implementaciones hardware de algoritmos criptográficos a la biblioteca OpenSSL la cual es utilizadapor aplicaciones sobre el sistema operativo Linux para asegurar redes TCP/IP. Los algoritmos implementados son el AES y las funciones resumen SHA-1 y SHA-256. Estos algoritmos son implementados como coprocesadores del procesador MicroBlaze utilizando interfaces FSL para el intercambio de datos entre ellos. Estos coprocesadores son integrados dentro de la biblioteca OpenSSL considerando la naturaleza multitarea del sistema operativo Linux, por lo que se selecciona un mecanismo de sincronización para controlar el acceso a estos dispositivos. Además son presentados los resultados de velocidad alcanzados por los coprocesadores integrados en la biblioteca utilizando la herramienta speed de la misma. Finalmente es presentado el impacto de estos coprocesadores en la velocidad de transmisión a través de una red privada virtual utilizando la herramienta OpenVPN.

Clasificación digital de masas nubosas a partir de imágenes meteorológicas usando algoritmos de aprendizaje de máquina

Directory of Open Access Journals (Sweden)

Salomón Einstein Ramírez-Fernández

2014-01-01

Full Text Available La identificación exacta de nubes precipitantes es una tarea difícil. En el presente trabajo se aplicaron los algoritmos Máquinas de Soporte Vectorial, Árboles de Decisión y Bosques Aleatorios para discriminar entre nubes precipitantes y nubes no precipitantes, a partir de una imagen meteorológica del satélite GOES-13 que cubre el territorio colombiano. El objetivo del trabajo fue evaluar el desempeño de los algoritmos de aprendizaje de máquina (ML, para la clasificación digital de masas nubosas, en términos de la exactitud temática de la clasificación usando como referencia el algoritmo convencional distancia de Mahalanobis. Los resultados muestran que los algoritmos ML proporcionan una clasificación de masas de nubes más exacta que la obtenida por algoritmos convencionales. La mejor exactitud fue obtenida usando Bosques Aleatorios (RF, con una exactitud temática global de 97%. Adicionalmente, la clasificación obtenida con RF fue comparada pixel a pixel con estimaciones de precipitación de la NASA Tropical Rainfall Measurement Mission (TRMM obteniendo una exactitud global del 94%. De acuerdo con este estudio, los algoritmos ML pueden ser usados para mejorar los actuales métodos de identificación de nubes precipitantes.

RECONFIGURACIÓN DE REDES ELÉCTRICAS DE MEDIA TENSIÓN BASADA EN EL ALGORITMO DE PRIM RECONFIGURATION OF MEDIUM VOLTAGE NETWORKS BASED ON PRIM'S ALGORITHM

Directory of Open Access Journals (Sweden)

Angely Cárcamo-Gallardo

2007-04-01

Full Text Available En este trabajo se presenta un nuevo algoritmo que permite reconfigurar un sistema de distribución (SD de energía eléctrica minimizando la energía no suministrada (ENS. El SD se modela utilizando teoría de grafos, mientras que la ENS se formula recursivamente y se parametriza en términos de los índices de confiabilidad del SD. Empleando esta modelación se transforma el problema de optimización en el problema de encontrar el árbol de mínima expansión (AME a partir del grafo que modela al SD, donde la métrica de distancia utilizada corresponde a la ENS a cada nodo del SD. Para encontrar de manera eficiente el AME se utiliza el algoritmo de Prim, ya que pertenece a la clase de algoritmos voraces en el cálculo del AME. Adicionalmente, se propone un algoritmo que realiza una revisión del AME obtenido analizando las topologías que fueron descartadas aleatoriamente durante el proceso de decisión. El desempeño del algoritmo de optimización se evalúa en sistemas de pruebas y en dos sistemas eléctricos reales.This paper presents a novel algorithm to reconfigure an electric power distribution network (EPDN, minimizing its non-supplied energy (NSE. The EPDN is modeled using graph theory and the NSE is recursively formulated in terms of the reliability parameters of the EPDN. Based on this mathematical model, we transform the original optimization problem into the graph theory problem of finding the minimum spanning tree (MST of a given graph, which models the EPDN. The distance metric employed by the searching algorithm is the NSE. In order to efficiently find the MST, Prim's algorithm is employed due to is greedy search behavior. In addition, a backtracking algorithm is used to check the MST obtained. The backtracking algorithm analyzes all the candidate topologies that were randomly discarded during the decision process. The performance of the optimization algorithm is evaluated using testing systems and two actual EPDNs.

Algoritmos para problemas de corte e empacotamento

OpenAIRE

Thiago Alves de Queiroz

2010-01-01

Resumo: Problemas de Corte e Empacotamento são, em sua maioria, NP-difíceis e não existem algoritmos exatos de tempo polinomial para tais se for considerado P ¿ NP. Aplicações práticas envolvendo estes problemas incluem a alocação de recursos para computadores; o corte de chapas de ferro, de madeira, de vidro, de alumínio, peças em couro, etc.; a estocagem de objetos; e, o carregamento de objetos dentro de contêineres ou caminhões-baú. Nesta tese investigamos problemas de Corte e Empacotament...

Algoritmo de lanczos na variedade de grassmann

OpenAIRE

Lopes, Ana Paula Ferreira Fernandes; Viamonte, Ana Júlia; Pascoal, António José

2008-01-01

O problema do cálculo de valores próprios, vectores próprios e subespaços invariantes está presente em áreas tão diversas como Engenharia, Física, Ciências de Computação e Matemática. Considerando a importância deste problema em tantas aplicações práticas, não é de surpreender que tenha sido e continue a ser objecto de intensa investigação, dando corpo a uma literatura muito vasta. Desenvolvemos um novo algoritmo de Lanczos na variedade de Grassmann. Este trabalho surgiu na ...

Algoritmos genéticos para la resolución de problemas de Programación por Metas Entera. Aplicación a la Economía de la Educación.

Directory of Open Access Journals (Sweden)

Caballero Fernández, Rafael

2002-01-01

Full Text Available En este trabajo se presenta un algoritmo genético para la resolución de problemas de Programación por Metas Entera. Este tipo de problemas presentan en general un gran número de dificultades para su resolución utilizando algoritmos tradicionales de Programación Entera, siendo en la mayoría de los casos de problemas reales demasiado costosa computacionalmente para afrontarla con garantías. Sin embargo, se mostrará como este nuevo tipo de algoritmos, los algoritmos genéticos, permiten resolver eficientemente problemas de este tipo con un coste computacional reducido. Como ejemplo, se resuelve en este trabajo un problema Economía de la Educación con un modelo de Programación por Metas Entera aplicando un algoritmo genético y un algoritmo tradicional. Para estas resoluciones se analiza el coste computacional de ambos tipos de resolución para poner de manifiesto las ventajas que puede suponer un algoritmo genético para la resolución de problemas reales complejos.

Algoritmo de um teste adaptativo informatizado com base na teoria da resposta ao item para a estimação da usabilidade de sites de e-commerce

Directory of Open Access Journals (Sweden)

Fernando de Jesus Moreira Junior

2013-09-01

Full Text Available O presente artigo propõe um algoritmo de um teste adaptativo informatizado baseado na teoria da resposta ao item, desenvolvido para estimar o grau de usabilidade de sites de e-commerce. Cinco algoritmos baseados no critério da máxima informação foram desenvolvidos e testados via simulação. O algoritmo com o melhor desempenho foi aplicado nos dados reais de 361 sites de e-commerce. Os resultados mostraram que o algoritmo desenvolvido consegue obter uma boa estimativa para o grau de usabilidade de sites de e-commerce com a aplicação de 13 itens.

Algoritmo para el tratamiento mínimamente invasivo de la coledocolitiasis

Directory of Open Access Journals (Sweden)

Javier Ernesto Barreras González

Full Text Available La coledocolitiasis se presenta en más del 10 % de los pacientes jóvenes sometidos a la colecistectomía laparoscópica y se incrementa por encima de 25 % en los pacientes mayores de 60 años. Una vez que se identifica el cálculo en la vía biliar principal (VBP, esto puede convertirse en un dilema terapéutico. En la actualidad, diferentes algoritmos se han planteado y están establecidos, pero las publicaciones internacionales continúan redefiniendo las indicaciones de la colangiopancreatografía retrógrada endoscópica sobre la exploración laparoscópica de la vía biliar principal y viceversa. El objetivo de este estudio fue presentar el algoritmo para el tratamiento de la coledocolitiasis del Centro Nacional de Cirugía de Mínimo Acceso de La Habana. Se realizó una amplia revisión bibliográfica acerca del manejo actual de la coledocolitiasis con vesícula in situ y se evaluaron los resultados de dichas técnicas en el Centro Nacional de Cirugía de Mínimo Acceso. Las opciones para el manejo de la coledocolitiasis incluyen la exploración transcística de la vía biliar principal, la exploración laparoscópica de la vía biliar principal mediante coledocotomía, la colangiopancreatografía retrógrada endoscópica preoperatoria e intraoperatoria con esfinterotomía. Se presenta el algoritmo para el tratamiento mínimamente invasivo de la coledocolitiasis. El manejo de esta enfermedad en la actualidad depende de la experiencia de cada equipo quirúrgico y de su disponibilidad de acceso a los avances tecnológicos.

Algoritmos paralelos numéricos para a resolução de sistemas de equações lineares

OpenAIRE

Maria Paula Goncalves Fachin

1989-01-01

Apresentamos as características de algoritmos para obter a solução de sistemas de equações lineares, utilizando computadores com arquitetura paralela e explorando os recursos de paralelismo neles embutidos. São descritos os modelos de computadores paralelos e os procedimentos para a criação de algoritmos paralelos. The characteristics of algorithms to solve systems of linear equations, using parallel computers, are presented. The abstract models of these computers are described, as well as...

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

OpenAIRE

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

2011-01-01

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

Determination of generator losses and efficiency

Directory of Open Access Journals (Sweden)

Klasnić Ilija

2015-01-01

Full Text Available The paper presents the results of deriving by calculation the local and total losses of the generator as well as efficiency determination of the revitalised hydro-generator unit A4 in HPP 'Djerdap 1'. In order to determine the generator losses and generator efficiency, measurements are performed during the acceptance tests of revitalised aggregate A4 in HPP 'Djerdap 1'.

Aplicativo para análise comparativa do comportamento de algoritmos de ordenação

Directory of Open Access Journals (Sweden)

João Paulo Folador

2014-11-01

Full Text Available Este artigo apresenta uma ferramenta prática de auxílio pedagógico para demonstrar o comportamento de alguns algoritmos de ordenação. Nesse contexto, foram estudados e confrontados os algoritmos: bubble sort, merge sort, quick sort e o shell sort, de modo a ordenar uma matriz de elementos variáveis. Na aplicação desenvolvida é permitido ao usuário configurar a quantidade de elementos da matriz a serem ordenados, quais métodos serão utilizados, a quantidade de ciclos somados e, o resultado final, é mostrado por meio de um gráfico, comparando os métodos aplicados. Ainda, como saída do processo de ordenação, são mostrados: o tempo médio de execução, o desvio padrão, o tempo mínimo e o tempo máximo gasto para ordenar os elementos da matriz. Desse modo, essa aplicação de apoio didático torna-se prática para testes feitos pelos alunos nas disciplinas que envolvem o estudo de algoritmos de ordenação facilitando, assim, o processo de aprendizagem.

ALGORITMO PARA EL APRENDIZAJE DE REGLAS DE CLASIFICACION BASADO EN LA TEORÍA DE LOS CONJUNTOS APROXIMADOS EXTENDIDA

Directory of Open Access Journals (Sweden)

YAIMA FILIBERTO

2011-01-01

Full Text Available Los conjuntos aproximados han demostrado ser efectivos para desarrollar técnicas de aprendizaje automático, entre ellos métodos para el descubrimiento de reglas de clasificación. En este trabajo se presenta un algoritmo para generar reglas de clasificación basado en relaciones de similaridad, lo que permite que sea aplicable en casos donde los rasgos tienen dominio discreto o continuo. Los resultados experimentales muestran un desempeño satisfactorio en comparación con otros algoritmos conocidos como C4.5 y MODLEM.

Algoritmo genético permutacional para el despliegue y la planificación de sistemas de tiempo real distribuidos

Directory of Open Access Journals (Sweden)

Ekain Azketa

2013-07-01

Full Text Available Resumen: El despliegue y la planificación de tareas y mensajes en sistemas de tiempo real distribuidos son problemas NP-difíciles (NP- hard, por lo que no existen métodos óptimos para solucionarlos en tiempo polinómico. En consecuencia, estos problemas son adecuados para abordarse mediante algoritmos genéricos de búsqueda y optimización. En este artículo se propone un algoritmo genético multiobjetivo basado en una codificación permutacional de las soluciones para abordar el despliegue y la planificación de sistemas de tiempo real distribuidos. Además de desplegar tareas en computadores y de planificar tareas y mensajes, este algoritmo puede minimizar el número de computadores utilizados, la cantidad de recursos computacionales y de comunicaciones empleados y el tiempo de respuesta de peor caso medio de las aplicaciones. Los resultados experimentales muestran que este algoritmo genético permutacional puede desplegar y planificar sistemas de tiempo real distribuidos de forma satisfactoria y en tiempos razonables. Abstract: The deployment and scheduling of tasks and messages in distributed real-time systems are NP-hard problems, so there are no optimal methods to solve them in polynomial time. Consequently, these problems are suitable to be approached with generic search and optimisation algorithms. In this paper we propose a multi-objective genetic algorithm based on a permutational solution encoding for the deployment and scheduling of distributed real-time systems. Besides deploying and scheduling tasks and messages, the algorithm can minimize the number of the used computers, the utilization of computing and networking resources and the average worst-case response times of the applications. The experiments show that this genetic algorithm can successfully synthesize complex distributed real-time systems in reasonable times. Palabras clave: Sistemas de tiempo real, Algoritmos de planificaci

Algoritmo de cifrado simétrico AES : Aceleración de tiempo de cómputo sobre arquitecturas multicore

OpenAIRE

Pousa, Adrián

2011-01-01

El objetivo de este trabajo es mostrar la aceleración en el tiempo de cómputo del algoritmo criptográfico Advanced Encryption Standard (AES) con clave de tamaño 128bits, que se obtiene al aprovechar el paralelismo que proveen las arquitecturas multicores actuales utilizando herramientas de programación paralela. AES es uno de los algoritmos de criptografía más usados en la actualidad, con el crecimiento de las redes y la información que se maneja hoy en día puede ser necesario cifra...

Algoritmos genéticos

Directory of Open Access Journals (Sweden)

José Jesús Martínez Páez

1998-10-01

Full Text Available Esta técnica se basa en el concepto de evolución a través de selección de los mejores individuos, y de los operadores genéticos de selección, reproducción y mutación. Se trata entonces, de definir un espacio de soluciones para el problema que se quiere solucionar, en una cadena de bits. A esto se le conoce como la codificación del cromosoma, donde cada bit, denominado gen  tiene cierto significado especial. Inicialmente el algoritmo genera al azar muchas de estas cadenas o seres, es decir, una población, que luego confronta can un ambiente, que es el problema solucionar o función que se quiere optimizar. De esta confrontación  o evaluación a que se somete cada ser. Se obtiene información sobre cómo se comporto cada uno. A través de métodos aleatorios, pero con probabilidad de selección proporcional a su comportamiento, es decir, a mejor comportamiento mayor probabilidad, se selecciona una nueva población de seres supuestamente mejores que la generación anterior.

Aplicación de algoritmos heurísticos en la construcción de la población inicial de algoritmos genéticos que resuelven el problema de planeamiento de la expansión de la transmisión

Directory of Open Access Journals (Sweden)

Antonio H. Escobar Z.

2011-01-01

Full Text Available En este artículo se analiza el impacto de seleccionar poblaciones iníciales de buena calidad para ser usadas en algoritmos genéticos, con el propósito de obtener mayor velocidad de convergencia y mejor calidad en las soluciones alcanzadas cuando se resuelve el problema del planeamiento de la expansión a largo plazo de los sistemas de transmisión de energía eléctrica. Los sistemas de prueba que se analizan corresponden a sistemas de alta complejidad, tradicionalmente usados en la literatura especializada. Para generar soluciones iníciales de buena calidad se utilizan algoritmos heurísticos constructivos, particularmente los más utilizados en problemas de planeamiento de la expansión de sistemas de transmisión. Se comparan los resultados obtenidos con los que entregan los algoritmos genéticos que usan poblaciones iniciales aleatorias. Los resultados muestran que una población inicial generada en forma heurística permite obtener soluciones de mejor o igual calidad y con esfuerzos computacionales menores, cuando se resuelven sistemas eléctricos de gran complejidad.

ALGORITMOS DE APRENDIZAGEM DE MÁQUINA E VARIÁVEIS DE SENSORIAMENTO REMOTO PARA O MAPEAMENTO DA CAFEICULTURA

Directory of Open Access Journals (Sweden)

Carolina Gusmão Souza

Full Text Available A cafeicultura é uma das principais culturas agrícolas do Brasil e realizar o mapeamento e monitoramento desta cultura é fundamental para conhecer sua distribuição espacial. Porém, mapear estas áreas utilizando imagens de Sensoriamento Remoto não é uma tarefa fácil. Sendo assim, este trabalho foi realizado com o objetivo de comparar o uso de diferentes variáveis e algoritmos de classificação para o mapeamento de áreas cafeeiras. O trabalho foi desenvolvido em três áreas diferentes, que são bastante significativas na produção de café. Foram utilizados 5 algoritmos de aprendizagem de máquinas e 7 combinações de variáveis: espectrais, texturais e geométricas, associadas ao processo de classificação. Um total de 105 classificações foram realizadas, 35 classificações para cada uma das áreas. As classificações que não usaram variáveis espectrais não resultaram em bons índices de acurácia. Nas três áreas, o algoritmo que apresentou as melhores acurácias foi o Support vector machine, com acurácia global de 85,33% em Araguari, 87% em Carmo de Minas e 88,33% em Três Pontas. Os piores resultados foram encontrados com o algoritmo Random Forest em Araguari, com acurácia global de 76,66% e com o Naive Bayes em Carmo de Minas e Três Pontas, com 76% e 82% de acerto. Nas três áreas, variáveis texturais, quando associadas às espectrais, melhoraram a acurácia da classificação. O SVM apresentou o melhor desempenho para as três áreas

Un algoritmo de clasificación incremental basado en los k vecinos más similares para datos mezclados

Directory of Open Access Journals (Sweden)

Guillermo Sánchez-Díaz

2013-01-01

Full Text Available En este trabajo, se presenta un algoritmo de clasificación incremental basado en los k vecinos más similares, el cual permite trabajar con datos mezclados y funciones de semejanza que no necesariamente son distancias. El algoritmo presentado es adecuado para procesar grandes conjuntos de datos, debido a que sólo almacena en la memoria principal de la computadora los k vecinos más similares procesados hasta el paso t, recorriendo una sola vez el conjunto de datos de entrenamiento. Se presentan resultados obtenidos con diversos conjuntos de datos sintéticos y reales.

Algoritmo genético permutacional para el despliegue y la planificación de sistemas de tiempo real distribuidos

OpenAIRE

Azketa, Ekain; Gutiérrez, J. Javier; Di Natale, Marco; Almeida, Luís; Marcos, Marga

2013-01-01

Resumen: El despliegue y la planificación de tareas y mensajes en sistemas de tiempo real distribuidos son problemas NP-difíciles (NP- hard), por lo que no existen métodos óptimos para solucionarlos en tiempo polinómico. En consecuencia, estos problemas son adecuados para abordarse mediante algoritmos genéricos de búsqueda y optimización. En este artículo se propone un algoritmo genético multiobjetivo basado en una codificación permutacional de las soluciones para abordar el despli...

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

Directory of Open Access Journals (Sweden)

Fernán Villa

2009-01-01

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

Afectos y algoritmos alternativos en las aulas de primaria

OpenAIRE

Gamazo Alonso, Natalia

2017-01-01

El presente Trabajo Fin de Grado (TFG) recoge una sencilla investigación sobre la evolución del dominio afectivo matemático de una muestra de niños que trabajan las matemáticas con el método ABN (Abierto Basado en Números) y de una muestra de alumnos que las trabajan mediante algoritmos tradicionales. Junto con el análisis de la evolución de la afectividad hacia las matemáticas a lo largo de los cursos académicos que conforman la Educación Primaria, se establece también una comparativa ent...

Simulador gráfico de algoritmos matemáticos

OpenAIRE

Alves, Luís; Balsa, Carlos; Pereira, Maria João

2016-01-01

O objetivo principal do trabalho de investigação foi desenvolver uma ferramenta computacional que possa ser usada por professores e alunos no ensino dos Métodos Numéricos. A ferramenta, designada por GraSMA (Graphical Simulator of Mathematical Algorithms), permite visualizar no ecrã a execução dos correspondentes algoritmos. Esta ferramenta integra vários softwares open source e baseia-se na anotação automática de código Octave com funções de inspeção que permitem captar a sucessão de valores...

Wind Turbine Generator Efficiency Based on Powertrain Combination and Annual Power Generation Prediction

Directory of Open Access Journals (Sweden)

Dongmyung Kim

2018-05-01

Full Text Available Wind turbine generators are eco-friendly generators that produce electric energy using wind energy. In this study, wind turbine generator efficiency is examined using a powertrain combination and annual power generation prediction, by employing an analysis model. Performance testing was conducted in order to analyze the efficiency of a hydraulic pump and a motor, which are key components, and so as to verify the analysis model. The annual wind speed occurrence frequency for the expected installation areas was used to predict the annual power generation of the wind turbine generators. It was found that the parallel combination of the induction motors exhibited a higher efficiency when the wind speed was low and the serial combination showed higher efficiency when wind speed was high. The results of predicting the annual power generation considering the regional characteristics showed that the power generation was the highest when the hydraulic motors were designed in parallel and the induction motors were designed in series.

Redes de Petri: Modelado e implementación de algoritmos para autómatas programables

Directory of Open Access Journals (Sweden)

Luis Diego Murillo

2008-04-01

Full Text Available El presente trabajo es una monografía orientada hacia la utilización del formalismo de las Redes de Petri, propuesto por Carl Petri en la descripción de Sistemas Dinámicos de Eventos Discretos (DEDS. Las Redes de Petri, cuyo acrónimo en inglés es PN, fueron utilizadas inicialmente para el análisis de algoritmos en la computación paralela o concurrente, pero dada la complejidad de los procesos productivos actuales, las PN son un método alternativo de diseño tanto para el procesoindustrial como para el controlador. En este sentido, este estudio hace una revisión de las referencias bibliográficas donde se indica cómo realizar el modelado y la implementación de algoritmos de control en Controladores Lógicos Programables (PLCs por sus siglas en inglés.

Un Algoritmo Genético Especializado en Planeamiento de Redes de Distribución. Parte II. Detalles del algoritmo y su aplicación; A specialized Genetic Algorithm in Distribution Network planning. Part II. Algorithm details and application

Directory of Open Access Journals (Sweden)

Raúl Nicolás Carvajal Pérez

2011-05-01

Full Text Available En la Parte I de este articulo, se expusieron las características de la planificación de redes y su influencia en la selección de métodos específicos en cada uno de los procedimientos para desarrollar los pasos del algoritmo genético especializado. Aquí se exponen las interioridades del algoritmo y el trabajo experimental para fijar la magnitud de los parámetros generales de las poblaciones y la cantidad de éstas. Se presentan casos resueltos durante el ajuste del sistema de cálculo.  The first section explained the specifics characteristics of network planning and the selected method for genetic operators. In this papers, expose details about the algorithm steps, the mathematical procedures and some applications.

ALGORITMO PARA EL ANÁLISIS PROBABILÍSTICO EN SISTEMAS DE DISTRIBUCIÓN CON GENERACIÓN DISTRIBUÍDA

Directory of Open Access Journals (Sweden)

CESAR AUGUSTO PEÑUELA MENESES

2011-01-01

Full Text Available Este artículo presenta un algoritmo eficiente para el análisis probabilístico de sistemas de distribución trifásicos desbalanceados con conexión de generadores distribuidos (sistemas levemente enmallados. Este algoritmo hace uso de la técnica del Método Estimado de Dos Puntos para el cálculo del comportamiento probabilístico de las variables aleatorias del sistema. Adicionalmente, y con el fin de explotar eficientemente las características topológicas de la red, el análisis determinístico de las variables de estado es realizado por medio de un Flujo de carga Radial Basado en Compensación (FCRBC. Para el tratamiento de la generacióndistribuida, se propone una estrategia para incorporar dentro del FCRBC un modelo simplificado del generador junto con un control de las variables de despacho en el punto de conexión con la red. De este modo, el nodo con generación distribuida puede ser modelado como un nodoPV, o nodo PQ, dependiendo del modo de control y de las condiciones operativas del generador. Para validar la eficiencia del algoritmo propuesto es usado el sistema de prueba IEEE de 37 nodos. Los resultados probabilísticos son comparados con los obtenidos usando el método de Monte Carlo.

Análisis de algoritmos de inteligencia artificial para videojuegos

OpenAIRE

Rico Zambrana, David

2016-01-01

Este documento contiene el Trabajo de Fin de Grado del alumno David Rico Zam- brana, estudiante del Grado en Ingeniería del Software, en la Universidad de Málaga. Este trabajo se ha realizado bajo la tutorización de Lorenzo Mandow Andaluz, pro- fesor del Departamento de Lenguajes y Ciencias de la Computación. El trabajo se titula Análisis de algoritmos de inteligencia artificial para vi- deojuegos, y consiste en el desarrollo de una aplicación usando Unity3D en la que se mue...

Prueba e implementación de algoritmos de control de calidad de datos de temperatura superficial del aire en un contexto operativo

Directory of Open Access Journals (Sweden)

José Araya

2008-04-01

Full Text Available Se presenta una metodología para el cálculo de rangos de temperatura, así como algoritmos de programación simple para la detección de errores obvios en datos meteorológicos con el fin de mostrar cómo un sistema de control de calidad sencillo, en tiempo real, puede implementarse de forma exitosa. Estos algoritmos fueron probados a través de su programación en un grabador de datos, el cual es el núcleo procesador en una estación meteorológica: primero, bajo condiciones controladas; y, luego, en dos estaciones meteorológicas automáticas con capacidad de transmisión en tiempo real. La investigación realizada muestra que estos algoritmos son efectivospara la detección de valores atípicos que de otra manera podrían ser detectados tardíamente y pasar inadvertidos.

Efficiency of poly-generating high temperature fuel cells

Energy Technology Data Exchange (ETDEWEB)

Margalef, Pere; Brown, Tim; Brouwer, Jacob; Samuelsen, Scott [National Fuel Cell Research Center (NFCRC), University of California, Irvine, CA 92697-3550 (United States)

2011-02-15

High temperature fuel cells can be designed and operated to poly-generate electricity, heat, and useful chemicals (e.g., hydrogen) in a variety of configurations. The highly integrated and synergistic nature of poly-generating high temperature fuel cells, however, precludes a simple definition of efficiency for analysis and comparison of performance to traditional methods. There is a need to develop and define a methodology to calculate each of the co-product efficiencies that is useful for comparative analyses. Methodologies for calculating poly-generation efficiencies are defined and discussed. The methodologies are applied to analysis of a Hydrogen Energy Station (H{sub 2}ES) showing that high conversion efficiency can be achieved for poly-generation of electricity and hydrogen. (author)

Algoritmo Novedoso Para la Detección de Tareas Repetitivas en el Teclado

Directory of Open Access Journals (Sweden)

Bairon Londo

2015-07-01

Full Text Available En este artículo una herramienta para la detección de tareas repetitivas con secuencias lógicas realizadas a través de comandos del teclado, mediante el diseño e implementación de un algoritmo basado en el uso de autómatas finitos determinísticos y agentes de búsqueda de patrones. La novedad del algoritmo desarrollado radica en que está orientado a la detección de tareas repetitivas cuyas actividades tienen una secuencia lógica y que actualmente no se encuentran automatizadas por lo complejo que es esta labor   Abstract This paper propose a tool  for the detection of repetitive tasks with logical sequences realized across command of the keyboard is proposed, by means of the design and implementation of an algorithm based on the use of finite automata deterministic and agents of bosses' search. The innovation of the developed algorithm takes root in that it is orientated to the detection of repetitive tasks which activities have a logical sequence and that nowadays are not automated by the complex thing that is this labor.

Identificación Inteligente de un Proceso Fermentativo Usando el Algoritmo GMDH Modificado

Directory of Open Access Journals (Sweden)

F. Hernández

2012-01-01

Full Text Available Resumen: En este trabajo se aborda, de manera particular, un método para el diseño del algoritmo conocido como Group Method of Data Handling, GMDH, típico con lazo recurrente. Una modificación en una de sus fases de entrenamiento permite ampliar el número de variables utilizadas en cada capa y con ello el área de regresión. Consecuentemente se puede obtener una estructura optimizada en sí misma de mayor complejidad, posibilitando la aparición de lazos recurrentes en las capas intermedias. Lo anterior permite una reducción del error en la modelación de procesos no lineales de lento comportamiento, como el crecimiento celular en biorreactores. El modelo se probó en una fermentación tipo feed-batch de la levadura Pichia pastoris. La estabilidad y capacidad de generalización es demostrada. El método propuesto es comparado con el GMDH típico recurrente y con otras estructuras de redes neuronales clásicas. Palabras clave: redes neuronales, recurrente, algoritmo genético, modelación, fermentación

METODOLOGÍA BASADA EN LOS ALGORITMOS VEGA Y MOGA PARA SOLUCIONAR UN PROBLEMA MULTIOBJETIVO EN UN SISTEMA DE PRODUCCIÓN JOB SHOP

Directory of Open Access Journals (Sweden)

Germán Augusto Coca Ortegón

Full Text Available En este artículo se presenta una metodología que pretende minimizar de forma simultánea, en un ambiente de producción tipo "job shop" correspondiente a una empresa metalmecánica, las siguientes variables: tiempo de proceso, costo de mano de obra directa y, asimismo la fracción defectuosa generada por la fatiga del operario. Con este propósito se fusionan elementos de los algoritmos genéticos Vega y Moga, desarrollando para el efecto las siguientes etapas: generar la población inicial, conformar la nueva población, realizar análisis de varianza y por último, comparar con un método híbrido entre sumas ponderadas y algoritmos genéticos. De acuerdo con lo anterior, al evaluar el individuo de menor tiempo de proceso proveniente de la metodología basada en los algoritmos Vega y Moga, respecto al individuo de menor tiempo de desarrollo proveniente del método híbrido entre sumas ponderadas y algoritmos genéticos, se encuentra que el primero supera en desempeño al segundo así: en cuanto a la variable tiempo de proceso (en horas en 27,86%; en cuanto a la variable tiempo de proceso (en semanas en 1,25%; en cuanto a la variable costo de mano de obra directa (MOD en 6,73% y, en cuanto a la variable fracción defectuosa en 25,85%.

Projeto de acopladores ópticos utilizando algoritmo genético

OpenAIRE

Jaqueline Oliveira Zampronio

2016-01-01

Resumo: Este projeto é uma proposta de um novo acoplador óptico para a aplicação em circuitos ópticos integrados. O dispositivo foi desenvolvido utilizando o método dos elementos finitos vetorial 3D associado com o algoritmo genético e leva em consideração guias de onda com diferentes altura, largura e índices de refração. O comprimento total do acoplador óptico é de apenas 4,22 µm e o seu funcionamento é baseado em pequenos segmentos cilíndricos que interferem na propagação da onda eletromag...

Combinación entre Algoritmos Genéticos y Aleatorios para la Programación de Horarios de Clases basado en Ritmos Cognitivos

OpenAIRE

Castrillón, Omar D

2014-01-01

Se ha diseñado un método basado en algoritmos evolutivos (genéticos y aleatorios) para programar los horarios de clases en una universidad. Esta metodología considera los ritmos cognitivos de los estudiantes que indican que es mejor enseñar algunas asignaturas en intervalos específicos de tiempo. Primero se describen las diferentes técnicas empleadas para desarrollar este problema. Luego se propone una nueva metodología basada en ritmos cognitivos y algoritmos evolutivos, para resolver todas ...

Algoritmo para monitoramento da incidência da malária na Amazônia brasileira, 2003 a 2010

Directory of Open Access Journals (Sweden)

Rui Moreira Braz

2014-03-01

Full Text Available OBJETIVO: Avaliar um algoritmo para detecção da variação da incidência da malária nos municípios da Amazônia brasileira. MÉTODOS: Avaliou-se um sistema de monitoramento automatizado, baseado em um algoritmo desenvolvido anteriormente pelos autores. O algoritmo utiliza o diagrama de controle por quartis para classificação dos municípios em quatro grupos, conforme a variação da incidência da malária: grupo 1 (redução da incidência-aqueles com incidência abaixo dos valores esperados; grupo 2 (incidência esperada-aqueles com incidência dentro dos valores esperados; grupo 3 (epidemia-aqueles com incidência acima dos valores esperados; grupo 4 (caso esporádico-aqueles com apenas um caso durante o ano. O período de análise foi de 2003 a 2010. Foram estudados todos os municípios existentes nos nove estados que compõem a Amazônia brasileira (805 municípios em 2003 e 807 a partir de 2004. RESULTADOS: Com base nessa metodologia, os municípios da região foram assim classificados: grupo 1, 152 municípios (18,8% da região em 2003 e 109 (13,5% em 2010; grupo 2, 206 (25,6% em 2003 e 331 (41,0% em 2010; grupo 3, 391 (48,6% em 2003 e 308 (38,2% em 2010; e grupo 4, 56 (7,0% em 2003 e 59 (7,3% em 2010. CONCLUSÕES: O algoritmo possibilitou verificar que, na Amazônia brasileira, o número de municípios com epidemias de malária em 2010 diminuiu em relação a 2003, enquanto o número de municípios com incidência esperada aumentou. No mesmo período, houve pouca variação no número de municípios com redução da incidência e daqueles com casos esporádicos.

Algoritmos evolucionários na determinação da configuração de custo mínimo de sistemas de co-geração de energia com base no gás natural

Directory of Open Access Journals (Sweden)

Marco César Goldbarg

2005-08-01

Full Text Available Esse trabalho apresenta um caso especial do problema geral da determinação de uma configuração para um sistema de co-geração de energia que utiliza o gás natural como fonte energética. O problema visa determinar a configuração de custo mínimo de um sistema de co-geração. É um problema computacionalmente difícil devido a restrições técnicas, operacionais e econômicas. Para solucioná-lo, são apresentados e comparados algoritmos evolucionários desenvolvidos de acordo com as metáforas dos Algoritmos Genéticos, Algoritmos Meméticos e da Transgenética Computacional. Os algoritmos são aplicados a um conjunto de trinta e cinco instâncias geradas de acordo com cinco diferentes ciclos de co-geração. Os experimentos computacionais relatados nesse trabalho indicam uma dominância de melhores resultados da metáfora transgenética.This work presents a special case of the general problem of determining the configuration of cogeneration systems in which the primary source of energy is natural gas. The objective is to determine the configuration with the minimum cost. Technical, operational and economic features impose constraints to the problem making it computationally hard to solve. Evolutionary algorithms based upon genetic, memetic and transgenetic algorithms are presented to solve the problem. A computational experiment with thirty-five instances generated in accordance with five distinct cogeneration cycles is reported. The results show that the transgenetic algorithm exhibits an overall best performance.

Algoritmos Wavenet con Aplicaciones en la Aproximación de Señales: un Estudio Comparativo

Directory of Open Access Journals (Sweden)

C.R. Domínguez Mayorga

2012-10-01

Full Text Available Resumen: En este trabajo de investigación se aplican métodos adaptables en el diseño de algoritmos computacionales, dichos algoritmos emplean redes neuronales y series de wavelets para construir “neuroaproximadores” wavenets. Se muestra cómo las wavenets pueden combinarse con los métodos autosintonizables para obtener el seguimiento de señles complejas que están en función del tiempo. Los algoritmos obtenidos se aplican en la aproximación de señales que representan funciones algebraicas y funciones aleatorias, así como en una señal médica deun ECG. Se muestran los resultados en simulación numérica de dos arquitecturas de neuroaproximadores wavenets: el primero está basado en una wavenet, con el cual se aproximan las señales bajo estudio donde los parámetros de la red neuronal son ajustados en línea; el otro esquema emplea un filtro IIR a la salida de la red wavenet para discriminar las contribuciones de aquellas neuronas que tienen menos peso en la aproximación de la señal, lo que ayuda a reducir el tiempo de convergencia a un error mínimo deseado. Abstract: In this paper adaptable methods for computational algorithms are presented. These algorithms use neural networks and wavelet series to build neuro wavenets approximators. The algorithms obtained are applied to the approximation of signals that represent algebraic functions and random functions, as well as a medical EKG signal. It shows how wavenets can be combined with auto-tuning methods for tracking complex signals that are a function of time. Results are shown in numerical simulation of two architectures of neural approximators wavenets: the first is based on a wavenet with which they approach the signals under study where the parameters of the neural network are adjusted online, the other neuro approximator scheme uses an IIR filter to the output of wavenet, which serves to filter the out- put, in this way

Mushrooms as Efficient Solar Steam-Generation Devices.

Science.gov (United States)

Xu, Ning; Hu, Xiaozhen; Xu, Weichao; Li, Xiuqiang; Zhou, Lin; Zhu, Shining; Zhu, Jia

2017-07-01

Solar steam generation is emerging as a promising technology, for its potential in harvesting solar energy for various applications such as desalination and sterilization. Recent studies have reported a variety of artificial structures that are designed and fabricated to improve energy conversion efficiencies by enhancing solar absorption, heat localization, water supply, and vapor transportation. Mushrooms, as a kind of living organism, are surprisingly found to be efficient solar steam-generation devices for the first time. Natural and carbonized mushrooms can achieve ≈62% and ≈78% conversion efficiencies under 1 sun illumination, respectively. It is found that this capability of high solar steam generation is attributed to the unique natural structure of mushroom, umbrella-shaped black pileus, porous context, and fibrous stipe with a small cross section. These features not only provide efficient light absorption, water supply, and vapor escape, but also suppress three components of heat losses at the same time. These findings not only reveal the hidden talent of mushrooms as low-cost materials for solar steam generation, but also provide inspiration for the future development of high-performance solar thermal conversion devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Algoritmo especializado aplicado ao planejamento da expansÃo de redes aÃreas de sistemas de distribuiÃÃo

OpenAIRE

Willian Douglas Ferrari MendonÃa

2014-01-01

No presente trabalho à apresentado o desenvolvimento de um algoritmo especializado para o planejamento da expansÃo de redes aÃreas de sistemas de distribuiÃÃo. A tÃcnica utilizada para soluÃÃo à a HeurÃstica Construtiva que tem sido utilizada em conjunto com modelos matemÃticos de otimizaÃÃo para resolver o problema. No entanto o algoritmo apresentado nÃo emprega um modelo matemÃtico de otimizaÃÃo, em outras palavras, um modelo composto de funÃÃo objetivo e restriÃÃes. Assim, em vez de trabal...

Diseño e implementación de un algoritmo para translación de protocolo entre las normas IEC60870-5-104 y MODBUS TCP/IP

OpenAIRE

Feria Briceño, John Henry; Universidad Distrital Francisco José de Caldas

2015-01-01

Este artículo muestra los resultados del proceso de diseño, implementación y prueba de un algoritmo para hacer la translación de protocolo entre las normas IEC 60870-5-104 y MODBUS TCP/IP, éste modelo de algoritmos son de amplio uso en los procesos de supervisión y automatización en sub-estaciones eléctricas.

El algoritmo HyRPNI y una aplicación en bioinformática

Directory of Open Access Journals (Sweden)

Gloria Inés Alvarez V.

2011-06-01

Full Text Available Proponemos un algoritmo de inferencia gramatical para lenguajes regulares que permite ahorrar cómputo al usar dos criterios diferentes para elegir los estados a ser procesados, un criterio se usa en la primera fase del proceso de inferencia (al principio y el otro en el resto del proceso. Realizamos experimentos para observar el desempeño del algoritmo, para aprender sobre el tamaño ideal de su primera fase y para mostrar su aplicación en la solución de un problema específico en bioinformática: la predicción de sitios de corte en poliproteínas codificadas por virus de la familia Potyviridae./ We propose a grammar inference algorithm for regular languages which saves computational cost by using two different criteria to choose states to be processed: one in the first phase of the inference process (the beginning and another for the rest of the process. We applied experiments to observe performance of the algorithm, to learn about the best size of its first phase and to show results of its application to solve a specific problem in Bioinformatics: the cleavage site prediction problem in polyproteins encoded by viruses of the Potyviridae family.

Estudio de Algoritmos 2-Deslizantes Aplicados al Control de Pilas de Combustible

OpenAIRE

Cristian Kunusch; Paul F. Puleston; Miguel A. Mayosky

2008-01-01

Resumen: En este trabajo se hace un estudio comparativo de tres diferentes técnicas de control por modo deslizante de segundo orden, aplicadas al problema específico del control de respiración de una pila de combustible PEM. Los algoritmos diseñados se contrastan por simulación utilizando el modelo completo del sistema, poniendo particular énfasis en la respuesta transitoria y la robustez frente a perturbaciones. Palabras clave: Pilas de Combustible, Control no lineal, Modo Deslizante

Absorption-reduced waveguide structure for efficient terahertz generation

Energy Technology Data Exchange (ETDEWEB)

Pálfalvi, L., E-mail: palfalvi@fizika.ttk.pte.hu [Institute of Physics, University of Pécs, Ifjúság ú. 6, 7624 Pécs (Hungary); Fülöp, J. A. [MTA-PTE High-Field Terahertz Research Group, Ifjúság ú. 6, 7624 Pécs (Hungary); Szentágothai Research Centre, University of Pécs, Ifjúság ú. 20, 7624 Pécs (Hungary); Hebling, J. [Institute of Physics, University of Pécs, Ifjúság ú. 6, 7624 Pécs (Hungary); MTA-PTE High-Field Terahertz Research Group, Ifjúság ú. 6, 7624 Pécs (Hungary); Szentágothai Research Centre, University of Pécs, Ifjúság ú. 20, 7624 Pécs (Hungary)

2015-12-07

An absorption-reduced planar waveguide structure is proposed for increasing the efficiency of terahertz (THz) pulse generation by optical rectification of femtosecond laser pulses with tilted-pulse-front in highly nonlinear materials with large absorption coefficient. The structure functions as waveguide both for the optical pump and the generated THz radiation. Most of the THz power propagates inside the cladding with low THz absorption, thereby reducing losses and leading to the enhancement of the THz generation efficiency by up to more than one order of magnitude, as compared with a bulk medium. Such a source can be suitable for highly efficient THz pulse generation pumped by low-energy (nJ-μJ) pulses at high (MHz) repetition rates delivered by compact fiber lasers.

UN ALGORITMO GENÉTICO HÍBRIDO Y UN ENFRIAMIENTO SIMULADO PARA SOLUCIONAR EL PROBLEMA DE PROGRAMACIÓN DE PEDIDOS JOB SHOP UM ALGORITMO GENÉTICO HÍBRIDO E UM ESFRIAMENTO SIMULADO PARA SOLUCIONAR O PROBLEMA DE PROGRAMAÇÃO DE PEDIDOS JOB SHOP A HYBRID GENETIC ALGORITHM AND A SIMULATED ANNEALING FOR SOLVING THE JOB SHOP SCHEDULING PROBLEM

Directory of Open Access Journals (Sweden)

José David Meisel

2010-07-01

mostraram que os algoritmos propostos arrojam bons resultados, com desvios ao redor dos melhores valores achados que não superam 5 % para os problemas mais complexos.Job Shop Scheduling Problem (JSP, classified as NP-Hard, has been a challenge for the scientific community because achieving an optimal solution to this problem is complicated as it grows in number of machines and jobs. Numerous techniques, including metaheuristics, have been used for its solution; however, the efficiency of the techniques, in terms of computational time, has not been very satisfactory. Because of this and for contributing to the solution of this problem, a simulated annealing (SA and an improved genetic algorithm (IGA have been proposed. The latter, by implementing a strategy of simulated annealing in the mutation phase, allows the algorithm to enhance and diversify the solutions at the same time, in order not to converge prematurely to a local optimum. The results showed that the proposed algorithms yield good results with deviations around the best values found not exceeding 5 % for more complex problems.

Relleno de huecos en mallas 3D completas mediante algoritmos de restauración de imagen

Directory of Open Access Journals (Sweden)

Emiliano Pérez Hernàndez

2012-10-01

Full Text Available Resumen: En este artículo se propone un método para rellenar huecos en objetos 3D. La idea principal es la de utilizar un algoritmo de restauración de imágenes para reconstruir las partes que se han de completar. Para ello es necesario hacer una transformación de los datos de la superficie 3D en datos de imagen 2D. Por tanto, el algoritmo propuesto parte de una etapa inicial de identificación de huecos. A continuación se hace la selección, para cada hueco, de una porción de malla representativa. Seguidamente se calcula el punto de vista o plano de proyección adecuado para obtener una imagen de rango de esa porción de malla. A la imagen de rango obtenida se le aplica el algoritmo de restauración de imagen. Finalmente, se aplica una transformación inversa 2D a 3D y se integra el éresultado con la malla inicial. Se trata de un algoritmo robusto, válido para diversos tipos de huecos y diferentes tamaños de los mismos. Abstract: In this work a method for filling holes in 3D meshes based on a 2D image restoration algorithm is expounded. To do that, data must be converted to a suitable input format, a 3D to 2D transformation is executed by projecting the 3D surface onto a grid. Therefore, the proposed algorithm starts by a first stage of holes identification. Then, a meaningful mesh portiéon is choosen for each hole. Afterward, the suitable plane of projection must be computed to get the range image of the mesh portion. Later, it is applied the restauration image algorithm to the range image. Finally, an inverse transformation 2D to 3D is performed and the new produced data are integrated with the initial mesh. The result is a robust algorithm which works correctly with several kind of holes and for di_erent sizes of them. Palabras clave: visión por computador, gráficos por computador, imágenes digitales, imágenes de rango, restauración de imágenes, Keywords: computer vision, computer graphics, digital images, range images

Algoritmos Numéricos para el Problema de Restauración de Imágenes usando el Método de las Proyecciones Alternantes

Directory of Open Access Journals (Sweden)

René Escalante

2011-04-01

Full Text Available Los algoritmos de proyección han evolucionado a partir del algoritmo de proyección alternante propuesto por J. von Neumann en 1933, donde el espacio solución es la intersección de un número finito de subespacios o conjuntos convexos. Investigaciones recientes se han centrado en técnicas para acelerar la convergencia del método y explotar el multiprocesamiento. En este trabajo consideramos el problema de restauración de imágenes. La mayoría de las técnicas desarrolladas para resolverlo han usado algoritmos iterativos; una de ellas consiste en usar proyecciones ortogonales alternantes. Llevamos a cabo una revisión cronológica de las diferentes técnicas en las que se ha aplicado el método de las proyecciones ortogonales alternantes al problema de restauración de imágenes, hasta llegar al enfoque reciente de Combettes (1997-1999, en donde la restauración se basa en el cálculo de proyecciones aproximadas, en lugar de proyecciones exactas.

Aplicação do algoritmo de contraponto dissonante de Tenney na determinação de parciais em espectros de sons concretos

Directory of Open Access Journals (Sweden)

Raphael Santos

2014-05-01

Full Text Available Neste artigo, propomos um sistema para determinação de harmonias espectrais extraídas de sons concretos a partir da utilização do algoritmo de contraponto dissonante, desenvolvido por James Tenney. Com base nesse algoritmo, definimos um sistema composicional, descrevemos sua implementação como aplicativo computacional e o utilizamos no planejamento composicional de duas obras originais: o primeiro movimento de um quarteto de clarinetes e um quinteto de metais.

Estudio de Algoritmos 2-Deslizantes Aplicados al Control de Pilas de Combustible

Directory of Open Access Journals (Sweden)

Cristian Kunusch

2008-07-01

Full Text Available Resumen: En este trabajo se hace un estudio comparativo de tres diferentes técnicas de control por modo deslizante de segundo orden, aplicadas al problema específico del control de respiración de una pila de combustible PEM. Los algoritmos diseñados se contrastan por simulación utilizando el modelo completo del sistema, poniendo particular énfasis en la respuesta transitoria y la robustez frente a perturbaciones. Palabras clave: Pilas de Combustible, Control no lineal, Modo Deslizante

Highly Flexible and Efficient Solar Steam Generation Device.

Science.gov (United States)

Chen, Chaoji; Li, Yiju; Song, Jianwei; Yang, Zhi; Kuang, Yudi; Hitz, Emily; Jia, Chao; Gong, Amy; Jiang, Feng; Zhu, J Y; Yang, Bao; Xie, Jia; Hu, Liangbing

2017-08-01

Solar steam generation with subsequent steam recondensation has been regarded as one of the most promising techniques to utilize the abundant solar energy and sea water or other unpurified water through water purification, desalination, and distillation. Although tremendous efforts have been dedicated to developing high-efficiency solar steam generation devices, challenges remain in terms of the relatively low efficiency, complicated fabrications, high cost, and inability to scale up. Here, inspired by the water transpiration behavior of trees, the use of carbon nanotube (CNT)-modified flexible wood membrane (F-Wood/CNTs) is demonstrated as a flexible, portable, recyclable, and efficient solar steam generation device for low-cost and scalable solar steam generation applications. Benefitting from the unique structural merits of the F-Wood/CNTs membrane-a black CNT-coated hair-like surface with excellent light absorbability, wood matrix with low thermal conductivity, hierarchical micro- and nanochannels for water pumping and escaping, solar steam generation device based on the F-Wood/CNTs membrane demonstrates a high efficiency of 81% at 10 kW cm -2 , representing one of the highest values ever-reported. The nature-inspired design concept in this study is straightforward and easily scalable, representing one of the most promising solutions for renewable and portable solar energy generation and other related phase-change applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concentrated Windings in Compact Permanent Magnet Synchronous Generators: Managing Efficiency

Directory of Open Access Journals (Sweden)

Olivier Barré

2016-01-01

Full Text Available In electric power generation, customers want generators with high efficiency. Nowadays, modern turbo-generators have efficiencies greater than 98%. Although this amount should not be obtained for all kind of machines, efficiency will remain one of the main parameters for customer choice. Efficiency is also linked to the life of the machine: the higher the efficiency is, the longer the machine’s lifetime. During the past decade, new forms of energy production have appeared and generators have been developed to fit well into this market. For example, wind generators evolved towards permanent magnet generators having high polarity and running at low speed. Nevertheless, their structure is not fixed. An industrial company has built a prototype of such a generator which uses fractional-slot concentrated-windings (FSCW. This kind of winding is not the structure used by default in such electrical machines. Another field of interest is in autonomous generators which can be used on boats. Even if everyone has in mind large merchant ships, we must not forget smaller ships, such as fishing boats and short-range cruise ships, which spend the most of their time near the coast. This kind of ship does nothave large areas for installing the electric generation or the electric propulsion. It is the reason why, in this article, we focus on the efficiency of machines using fractional-slot concentrated-windings. In many publications which compare performances between distributed and concentrated windings, the result is almost the same. The efficiency of FSCW is not as high as the efficiency associated to the machines which are using distributed windings. Design methods have to be redrawn to integrate, as soon as possible, the loss mitigation in order to provide the best efficiency in power conversion. The following discussion, step by step, introduces the loss mitigation in every part of a machine using FSCW. To close the discussion, a design is produced and it

Efecto del tamaño del alfabeto en el rendimiento de un algoritmo de compresión probabilístico

Directory of Open Access Journals (Sweden)

Carlos Rincón

2012-12-01

Full Text Available El presente trabajo tuvo como finalidad determinar el efecto del tamaño del alfabeto de un mensaje, en el rendimiento del algoritmo de compresión probabilístico basado en la posición de los símbolos, el cual propusimos en un trabajo previo (Rincón, Acurero, Bracho y Jakymec, 2008. La metodología utilizada consistió en 7 etapas: (a determinación de las variables dependientes e independientes a objeto de estudio, (b desarrollo e implementación del algoritmo propuesto, (c construcción de los archivos de prueba, (d ejecución del algoritmo implementado sobre los archivos de prueba, (e determinación del modelo matemático que explique el comportamiento de las variables dependientes, (f aplicación del método estadístico análisis de varianza, (g análisis de los resultados obtenidos. Las variables dependientes seleccionadas fueron el tiempo de compresión y la relación de compresión. El diseño del modelo estadístico seleccionado fue un totalmente aleatorizado con tratamiento en un arreglo factorial 4x2, con dos factores: tamaño del alfabeto (4,8,12 y 16 símbolos y distribucción probabilística del alfabeto (aleatorio y equiprobable. Del análisis de varianza se obtuvo diferencias significativas para todas las variables independientes y su interacción en todas las variables dependientes, corroborando así el efecto que tiene el tamaño del alfabeto en el rendimiento del algoritmo de compresión estudiado. La prueba de Tukey determinó que para la variable tiempo de compresión el mejor rendimiento se obtiene con la distribución aleatoria y el mayor tamaño del alfabeto (12 y 16, mientras que para la variable relación de compresión, el mejor rendimiento se obtiene con la distribución aleatoria y el menor tamaño del alfabeto.

Entropy-generated power and its efficiency

DEFF Research Database (Denmark)

Golubeva, N.; Imparato, A.; Esposito, M.

2013-01-01

We propose a simple model for a motor that generates mechanical motion by exploiting an entropic force arising from the topology of the underlying phase space. We show that the generation of mechanical forces in our system is surprisingly robust to local changes in kinetic and topological paramet...... parameters. Furthermore, we find that the efficiency at maximum power may show discontinuities....

Aplicação de um algoritmo genético para o problema do carteiro chinês em uma situação real de cobertura de arcos

Directory of Open Access Journals (Sweden)

Flavia Konowalenko

2012-04-01

Full Text Available O Problema do Carteiro Chinês é um problema de otimização que objetiva cobrir todos os arcos de um grafo, minimizando a distância total percorrida. Pode ser aplicado a grafos não-direcionados (ruas de mão dupla, direcionados (ruas de mão única ou mistos (algumas ruas de mão dupla e outras de mão única. A busca pela rota é feita por algoritmos que geram soluções aproximadas. Neste trabalho será utilizado um Algoritmo Genético para a construção de rotas que se aproximem da solução ótima. O objetivo principal será o de minimizar o custo do percurso da coleta e transporte dos resíduos sólidos urbanos, na cidade de Irati (PR, Brasil. O objetivo da modelagem foi a redução dos gastos dos recursos públicos, gerando economia à Prefeitura da cidade. A aplicação do algoritmo foi realizada em uma região central da cidade. Foram utilizados para mapeamento, dados reais cedidos por funcionários da Prefeitura. Com o auxílio do aplicativo online Google Earth, foram obtidas as coordenadas geográficas dos vértices do grafo associado ao problema. Os resultados gerados pelo algoritmo genético foram comparados com a solução ótima obtida através do software LINGO®12.0. Estes resultados se mostraram satisfatórios para a pequena instância do problema analisado. The Chinese Postman Problem is an optimization problem that aims to cover all the arcs of a graph, minimizing the total distance traveled. Can be applied to non-directed graphs (two-way streets, directed (one-way streets or mixed (some two-way streets and other one-way.These arch for the route is done by algorithms that generate approximate solutions. In this work we used a genetic algorithm for the construction of routes that approximate the optimal solution. The main objective is to minimize the cost of the course of collection and transportation solid waste in the city of Irati (PR, Brazil. The application of the algorithm was performed in a downtown area. Were used

Virtual Generation (Energy Efficiency) The Cheapest Source For Power Generation

Energy Technology Data Exchange (ETDEWEB)

Hasnie, Sohail

2010-09-15

Energy efficiency is the cheapest source of energy that has escaped the minds of the politicians in the developing countries. This paper argues for large scale utility led end use efficiency programs in a new paradigm, where 1 million efficient light bulbs is synonymous to a 50 MW power station that costs only 2% of the traditional fossil fuel power station and zero maintenance. Bulk procurement, setting up new standards and generation of certified emissions reduction is part of this strategy. It discusses implementation of a $20 million pilot in the Philippines supported by the Asian Development Bank.

Efficient Multiphoton Generation in Waveguide Quantum Electrodynamics

Science.gov (United States)

González-Tudela, A.; Paulisch, V.; Kimble, H. J.; Cirac, J. I.

2017-05-01

Engineering quantum states of light is at the basis of many quantum technologies such as quantum cryptography, teleportation, or metrology among others. Though, single photons can be generated in many scenarios, the efficient and reliable generation of complex single-mode multiphoton states is still a long-standing goal in the field, as current methods either suffer from low fidelities or small probabilities. Here we discuss several protocols which harness the strong and long-range atomic interactions induced by waveguide QED to efficiently load excitations in a collection of atoms, which can then be triggered to produce the desired multiphoton state. In order to boost the success probability and fidelity of each excitation process, atoms are used to both generate the excitations in the rest, as well as to herald the successful generation. Furthermore, to overcome the exponential scaling of the probability of success with the number of excitations, we design a protocol to merge excitations that are present in different internal atomic levels with a polynomial scaling.

Algorithms for the evaluation of the reliability of networks and substations; Algoritmos para evaluar la confiabilidad de redes y subestaciones electricas

Energy Technology Data Exchange (ETDEWEB)

Vega Ortiz, Miguel [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

2001-07-01

Two algorithms are presented, one for analyzing the reliability of networks and another one to analyzing the reliability of electrical substations. The algorithms model a network or a substation by means of a graph and determine all the exits, of up to third degree, which isolates the load points. The algorithm that is used for the network analysis, is the one of p-cuts and in the case of the substations it is the one of minimum ways, for later, from these minimum p-cuts and of the minimum ways, obtains the minimum cuts. These minimum cuts are evaluated with the approximate method and give as a result the system reliability and of each one of the components that have been modeled. At the end some examples and results obtained are shown. As case of study, the algorithm is applied to two substations arrangements and to a network of industrial distribution, but it is possible to be applied to transmission and distribution networks. [Spanish] Se presentan dos algoritmos, uno para analizar la confiabilidad de redes y otro para analizar la confiabilidad de subestaciones electricas. Los algoritmos modelan una red o una subestacion por medio de un grafo y determinan todas las salidas, de hasta tercer grado, que aislan los puntos de carga. El algoritmo que se utiliza para el analisis de redes, es el de p-cortes y en el caso de las subestaciones es el de caminos minimos, para despues, a partir de estos p-cortes minimos y de los caminos minimos, obtener los cortes minimos. Estos cortes minimos se evaluan con el metodo aproximado y dan como resultado la confiabilidad del sistema y de cada una de las componentes que se hayan modelado. Al final se muestran algunos ejemplos y resultados obtenidos. Como caso de estudio, el algoritmo se aplica a dos arreglos de subestaciones y a una red de distribucion industrial, pero se puede aplicar a redes de transmision y de distribucion.

GENERALIZACIÓN ALGEBRAICA DE LA DFC: REFLEXIONES POR MEDIO DE UN ALGORITMO ALGEBRAICO

Directory of Open Access Journals (Sweden)

Antonio Geloneze Neto

2012-09-01

Full Text Available La Demostración de Flujos de Caja (DFC pasó a ser un informe obligatorio por la contabilidad a partir del 1 de enero de 2008 para todas las empresas de capital abierto o con patrimonio líquido superior a dos millones de rea¬les y, de esa forma, se torna otro importante informe para la toma de decisiones gerenciales. Este trabajo tiene por objetivo proponer una generalización algébrica para la DFC. Papeles de trabajo pueden contribuir para cerrar una laguna didáctica en la enseñanza de la DFC y producir el método indirecto y el método directo, lado a lado con su equivalencia destacada, en una misma matriz por medio de algoritmos algebraicos. La pesquisa es de naturale¬za normativa y enfatiza el carácter transversal entre la Contabilidad y la Matemática, mostrando que los informes contables y sus estructuras pueden ser vistos como matrices y sujetos a deducciones algebraicas sobre los eventos registrados por medio de las partidas dobles. Como resultado, se pudo demostrar un algoritmo matemático con matrices y sub-matrices y un guión en el formato de papeles de trabajo, compatibles con las orientaciones norma¬tivas para la DFC en la legislación brasileña, que permite una DFC clara, segura y efectiva.

OTIMIZAÇÃO USANDO ALGORITMO GENÉTICO DE UM MODELO DE PROPAGÇÃO BASEADO EM EQUAÇÕES PARABÓLICAS

Directory of Open Access Journals (Sweden)

Antonio Carlos Vilanova

2013-01-01

Full Text Available Este artigo apresenta uma avaliação metodológica para otimizar parâmetros em um conhecido modelo de propagação de ondas de rádio na troposfera. O modelo de propagação é baseado no Divisor de passos de Fourier para resolver equações parabólicas. Nossa abordagem utiliza algoritmo genético para determinar os valores dos parâmetros que maximize a intensidade de campo em uma determinada posição do observador. Usando algoritmo genético o tempo necessário na busca dos parâmetros ótimos é reduzido significativamente. A avaliação preliminar dos resultados através da simulação mostra que a nossa abordagem é promissora.

Generalización algebraica de la DFC: reflexiones por medio de un algoritmo algebraico

Directory of Open Access Journals (Sweden)

Antonio Geloneze Neto

2012-01-01

Full Text Available La Demostración de Flujos de Caja (DFC pasó a ser un informe obligatorio por la contabilidad a partir del 1 deenero de 2008 para todas las empresas de capital abierto o con patrimonio líquido superior a dos millones de realesy, de esa forma, se torna otro importante informe para la toma de decisiones gerenciales. Este trabajo tiene porobjetivo proponer una generalización algébrica para la DFC. Papeles de trabajo pueden contribuir para cerrar unalaguna didáctica en la enseñanza de la DFC y producir el método indirecto y el método directo, lado a lado consu equivalencia destacada, en una misma matriz por medio de algoritmos algebraicos. La pesquisa es de naturalezanormativa y enfatiza el carácter transversal entre la Contabilidad y la Matemática, mostrando que los informescontables y sus estructuras pueden ser vistos como matrices y sujetos a deducciones algebraicas sobre los eventosregistrados por medio de las partidas dobles. Como resultado, se pudo demostrar un algoritmo matemático conmatrices y sub-matrices y un guión en el formato de papeles de trabajo, compatibles con las orientaciones normativaspara la DFC en la legislación brasileña, que permite una DFC clara, segura y efectiva.

Un algoritmo basado en búsqueda tabú granular para la solución de un problema de ruteo de vehículos considerando flota heterogénea

Directory of Open Access Journals (Sweden)

Duván Eduardo Puenayán

2014-12-01

Full Text Available Este artículo aborda el problema de ruteo de vehículos con flota heterogénea (VRPH, en el cual se busca determinar las rutas a ser construidas para satisfacer las demandas de los clientes, considerando una flota de vehículos con capacidad y costos no homogéneos. El objetivo es minimizar la distancia total de las rutas recorridas por los diferentes vehículos. En este artículo, se propone un algoritmo metaheurístico basado en una búsqueda tabú granular para la solución del problema. El algoritmo acepta soluciones infactibles penalizadas por un factor dinámico que se ajusta durante la búsqueda. Experimentos computacionales en instancias reales de una compañía colombiana muestran que el algoritmo propuesto es capaz de obtener, en tiempos computacionales reducidos, mejores soluciones que las obtenidas por el método tradicional de planificación de rutas, usado en la compañía.

Un nuevo algoritmo para la optimación de estructuras: el recocido simulado

Directory of Open Access Journals (Sweden)

Vázquez Espí, Mariano

1995-04-01

método de resolución, salvo para ciertos casos particulares en los que la función y sus variables satisfacen condiciones específicas (continuidad, diferenciabilidad, etc.. En numerosos casos de índole práctica no se dan tales condiciones y, en consecuencia, la solución al problema se aproxima, existiendo para ello una variedad de métodos heurísticos. El recocido simulado es un algoritmo de aproximación a la solución óptima, fundado en una analogía con el comportamiento de sistemas termodinámicos simples y viene siendo utilizado en ciertos problemas de ingeniería. El presente trabajo muestra cómo usarlo en la teoría de estructuras, señalando sus ventajas (universalidad así como sus inconvenientes (lentitud. Para ello, se describen brevemente los distintos problemas de la teoría de estructuras, así como aspectos fundamentales de la teoría de algoritmos. Con mayor detalle, se describe la forma matemática del algoritmo de recocido. En ambos casos se emplea un problema paradigmático de optimación: el del viajante de comercio. Finalmente, se muestra el empleo del algoritmo para "aproximar" formas óptimas de cerchas isostáticas.

Desempeño de Algoritmos Gusano en la Navegación de una Plataforma Robótica Móvil

Directory of Open Access Journals (Sweden)

Luis Alvarez

2013-11-01

Full Text Available El presente trabajo presenta la implementación de algoritmos de navegación denominados gusano 1 y gusano 2 sobre la plataforma robotica móvil de iRobot Create, los cuales se brindaron la capacidad de autonomía para navegar dentro de entornos desconocidos. Además, se utilizaron los módulos de radio frecuencia, que funcionan bajo el estándar ZigBee, para dotar de comunicación inalambrica entre el robot y una PC. Se realizaron pruebas de comunicación para determinar la máxima distancia de trabajo a la que pueden funcionar los módulos RF en interiores; mientras que, para el análisis de desempeño de los algoritmos básicos de navegación montados sobre la plataforma robótica móvil se definieron tres escenarios diferentes donde se verificó la certeza de haber alcanzado la meta por el robot.

Impacto de la memoria cache en la aceleración de la ejecución de algoritmo de detección de rostros en sistemas empotrados

Directory of Open Access Journals (Sweden)

Alejandro Cabrera Aldaya

2012-06-01

Full Text Available En este trabajo se analiza el impacto de la memoria cache sobre la aceleración de la ejecución del algoritmo de detección de rostros de Viola-Jones en un sistema de procesamiento basado en el procesador Microblaze empotrado en un FPGA. Se expone el algoritmo, se describe una implementación software del mismo y se analizan sus funciones más relevantes y las características de localidad de las instrucciones y los datos. Se analiza el impacto de las memorias cache de instrucciones y de datos, tanto de sus capacidades (entre 2 y 16 kB como de tamaño de línea (de 4 y 8 palabras. Los resultados obtenidos utilizando una placa de desarrollo Spartan3A Starter Kit basada en un FPGA Spartan3A XC3S700A, con el procesador Microblaze a 62,5 MHz y 64 MB de memoria externa DDR2 a 125 MHz,  muestran un mayor impacto de la cache de instrucciones que la de datos, con valores óptimos de 8kB para la cache de instrucciones y entre 4 y 16kB para la cache de datos. Con estas memorias se alcanza una aceleración de 17 veces con relación a la ejecución del algoritmo en memoria externa. El tamaño de la línea de cache tiene poca influencia sobre la aceleración del algoritmo.

Algoritmo evolucionário para otimização do plano de tratamento em radioterapia conformal 3D

Directory of Open Access Journals (Sweden)

Marco César Goldbarg

2009-08-01

Full Text Available O planejamento do tratamento por radioterapia tem por objetivo atingir um volume alvo com altas doses de radiação tomando cuidado para não expor órgãos sadios a doses elevadas. É, portanto, muito importante que se encontre um balanço ideal entre esses objetivos conflitantes. O presente trabalho relata um modelo de programação matemática multiobjetivo e introduz um Algoritmo Transgenético para o problema de seleção do direcionamento dos feixes de radiação no planejamento em radioterapia conformal 3D. A seleção das direções dos feixes é feita através de uma técnica denominada de isocentros variáveis. Com a finalidade de testar o potencial do algoritmo desenvolvido, realiza-se um experimento comparativo com um Algoritmo Genético Multiobjetivo. O experimento computacional obtém dados quantitativos e qualitativos que são analisados no trabalho.The radiotherapy treatment planning aims to achieve a target volume with high doses of radiation taking care not to expose healthy organs to high doses. It is therefore very important to find an optimal balance between these conflicting goals. This paper reports a mathematical model of multiobjective programming and presents a Transgenetic Algorithm for the problem of selecting the direction of radiation beams in 3D conformal radiotherapy planning. The selection of beams directions is done with a technique called variable isocenters. In order to test the potential of the developed algorithm, a comparative experiment with a multiobjective genetic algorithm was done. The computational experiment obtains quantitative and qualitative data that are analyzed in this paper.

Algoritmo genético para reducir el makespan en un flow shop híbrido flexible con máquinas paralelas no relacionadas y tiempos de alistamiento dependientes de la secuencia

Directory of Open Access Journals (Sweden)

Juan Camilo López-Vargas

2015-01-01

Full Text Available El artículo propone el algoritmo genético simple o estándar (AGS como enfoque de solución al problema de programación de produc - ción para un ambiente tipo flow shop híbrido flexible minimizando el makespan. La codificación del algoritmo propuesto permite obtener resultados con tiempos de cómputo bastante razonables y con un nivel de convergencia del makespan cercano al 2%, con mejores solu - ciones que un algoritmo alternativo diseñado para el mismo caso de programación de producción. A partir de los resultados obtenidos en el proceso de experimentación y del posterior análisis comparativo, se concluye que a partir del modelamiento más completo de las condiciones reales de producción, el algoritmo genético ejecuta la programación de producción reduciendo el tiempo máximo de procesamiento, o makespan. En futuros trabajos, el enfoque de investigación será la búsqueda de más escenarios alternativos de producción, con el fin de incrementar la aplicación de este tipo de herramientas y generar impacto en los entornos empresariales reales.

Improvement of hydro-turbine draft tube efficiency using vortex generator

Directory of Open Access Journals (Sweden)

Xiaoqing Tian

2015-07-01

Full Text Available Computational fluid dynamics simulation was employed in a hydraulic turbine (from inlet tube to draft tube. The calculated turbine efficiencies were compared with measured results, and the relative error is 1.12%. In order to improve the efficiency of the hydraulic turbine, 15 kinds of vortex generators were installed at the vortex development section of the draft tube, and all of them were simulated using the same method. Based on the turbine efficiencies, distribution of streamlines, velocities, and pressures in the draft tube, an optimal draft tube was found, which can increase the efficiency of this hydraulic turbine more than 1.5%. The efficiency of turbine with the optimal draft tube, draft tube with four pairs of middle-sized vortex generator, and draft tube without vortex generator under different heads of turbine (5–14 m was calculated, and it was verified that these two kinds of draft tubes can increase the efficiency of this turbine in every situation.

Technology Roadmap: High-Efficiency, Low-Emissions Coal-Fired Power Generation

Energy Technology Data Exchange (ETDEWEB)

NONE

2012-07-01

Coal is the largest source of power globally and, given its wide availability and relatively low cost, it is likely to remain so for the foreseeable future. The High-Efficiency, Low-Emissions Coal-Fired Power Generation Roadmap describes the steps necessary to adopt and further develop technologies to improve the efficiency of the global fleet of coal. To generate the same amount of electricity, a more efficient coal-fired unit will burn less fuel, emit less carbon, release less local air pollutants, consume less water and have a smaller footprint. High-efficiency, low emissions (HELE) technologies in operation already reach a thermal efficiency of 45%, and technologies in development promise even higher values. This compares with a global average efficiency for today’s fleet of coal-fired plants of 33%, where three-quarters of operating units use less efficient technologies and more than half is over 25 years old. A successful outcome to ongoing RD&D could see units with efficiencies approaching 50% or even higher demonstrated within the next decade. Generation from older, less efficient technology must gradually be phased out. Technologies exist to make coal-fired power generation much more effective and cleaner burning. Of course, while increased efficiency has a major role to play in reducing emissions, particularly over the next 10 years, carbon capture and storage (CCS) will be essential in the longer term to make the deep cuts in carbon emissions required for a low-carbon future. Combined with CCS, HELE technologies can cut CO2 emissions from coal-fired power generation plants by as much as 90%, to less than 100 grams per kilowatt-hour. HELE technologies will be an influential factor in the deployment of CCS. For the same power output, a higher efficiency coal plant will require less CO2 to be captured; this means a smaller, less costly capture plant; lower operating costs; and less CO2 to be transported and stored.

Análisis paramétrico de volúmenes arquitectónicos con algoritmos genéticos

Directory of Open Access Journals (Sweden)

Pedro Salcedo Lagos

2012-06-01

Full Text Available En el último tiempo el diseño arquitectónico ha venido evolucionando, debido entre otros aspectos, a la aparición de técnicas de diseño digital que permiten la generación de geometrías a partir de la definición de parámetros iniciales y la programación de las relaciones formales entre ellos. Los procesos de diseño basados en estas tecnologías permiten describir formas con capacidad de variar y adaptarse a requerimientos múltiples o a criterios de evaluación específicos, surgiendo así el problema de identificar la mejor solución arquitectónica, lo que se ha planteado en varias experiencias, gracias a la utilización de la técnica de algoritmos genéticos. En este trabajo se demuestra la posibilidad de implementar un análisis paramétrico de volúmenes arquitectónicos con algoritmos genéticos, logrando compatibilizar requerimientos funcionales, ambientales y estructurales, con un método efectivo de búsqueda para seleccionar una variedad de soluciones apropiadas gracias a las tecnologías digitales.

CREACIÓN DEL ALGORITMO HEURÍSTICO PARA LA PLANIFICACIÓN Y PROGRAMACIÓN DE CARTERAS DE PROYECTOS CON RECURSOS LIMITADOS

Directory of Open Access Journals (Sweden)

Mª Antonia Simón Rodríguez

2014-12-01

Full Text Available Existen numerosas empresas que tienen implantada una Oficina de Proyectos y los gestionan de manera unificada. Uno de los principales problemas que se encuentran es la asignación de los recursos humanos a los proyectos de cara a cumplir con los plazos establecidos. El objetivo del presente artículo es crear un nuevo algoritmo heurístico que logre resolverlo en un entorno dinámico, que tenga en cuenta las incidencias que van sucediendo, buscando el cumplimiento de hitos intermedios, dando continuidad a los recursos en un mismo proyecto y asignando distintas prioridades. Se ha realizado un estudio de la literatura referente al entorno multiproyecto y para el caso particular de carteras de proyectos. El algoritmo resultante logra satisfacer los objetivos propuestos con gran eficacia y eficiencia, logrando cumplir el plazo para todos los proyectos con prioridad crítica, respetar las fechas intermedias y logrando la nivelación de los recursos humanos disponibles.

Estimativa do balanço de energia utilizando imagens TM - Landsat 5 e o algoritmo SEBAL no litoral sul de Pernambuco

Directory of Open Access Journals (Sweden)

Célia Cristina Machado

2014-03-01

Full Text Available As trocas de energia na interface solo-planta-atmosfera, por meio das componentes do balanço de radiação (Rn e dos fluxos de calor no solo (G, sensível (H e latente (LE, são essenciais para a modelagem climática e hidrológica que, por sua vez, afetam toda a biosfera. Dessa forma, esta pesquisa teve por objetivos: (1 estimar e comparar o comportamento dos componentes do balanço de energia, usando o algoritmo SEBAL - Surface Energy Balance Algorithm for Land, em diferentes tipos de uso e cobertura do solo e (2 validar o algoritmo. Para isso, foram usadas três imagens TM - Landsat 5 de órbita e ponto 214/066, com datas de passagem em 26 de agosto de 2006, 6 de setembro de 2010 e 28 de janeiro de 2011, todas recortadas para enquadrar o litoral sul de Pernambuco. Os resultados mostraram a capacidade do SEBAL de estimar a variabilidade espacial dos diferentes componentes do balanço de energia, com capacidade de distinguir diferentes ocupações do solo. O cômputo do balanço de energia possibilita observar as formas diferenciadas do uso da energia pelos diferentes tipos de cobertura do solo e verificar aqueles que propiciam melhor conforto térmico. As estimativas da evapotranspiração obtidas pelo algoritmo SEBAL apresentaram uma boa concordância com os resultados obtidos pelo método da FAO-Penman-Monteith demonstrando, dessa forma, a potencialidade da abordagem metodológica escolhida.

Solución de un problema de secuenciamiento en configuración jobshop flexible utilizando un Algoritmo de Estimación de Distribuciones.

Directory of Open Access Journals (Sweden)

R. Pérez

2015-01-01

Full Text Available Resumen: El problema de secuenciamiento en configuración jobshop flexible se refiere en asignar operaciones de diversos trabajos a un conjunto de equipos disponibles. La asignación mencionada busca generalmente minimizar el tiempo de culminación de todos los trabajos conocido en la literatura como ‘makespan’. Se propone un Algoritmo de Estimación de Distribuciones para Secuenciamiento, AEDS por simplicidad y funcionalidad. El AEDS intenta encontrar una relación o interacción entre las variables de entrada, trabajos, operaciones y turnos de trabajo, para optimizar la variable de salida de procesos de manufactura reales, el makespan. En este sentido el algoritmo AEDS es usado para guiar la búsqueda y resolver el problema. En el marco del algoritmo, tres modelos gráficos fueron usados para encontrar mejores soluciones. Establecer horas fuera de servicio para los operadores antes de iniciar sus actividades en cada turno de trabajo como parámetro de entrada y su desarrollo a través del algoritmo AEDS constituye una novedad de esta investigación respecto los trabajos existentes. La comparación entre AEDS y un algoritmo genético muestra la efectividad del AEDS resolviendo el problema enunciado. Usando el AEDS propuesto, el desempeño de procesos de manufactura reales mejora notablemente cuando diferentes equipos disponibles son asignados a diferentes programas de producción. Abstract: The flexible jobshop scheduling problem permits the operation of each job to be processed by more than one machine. The configuration mentioned generally seeks to minimize the completion time of all jobs known in the literature as ‘makespan’. We propose an Estimation of Distribution Algorithm for Sequencing, AEDS for simplicity and functionality. The AEDS attempts to find a relationship or interaction between the input variables, jobs, operations and shifts to optimize the output variable of real

Unificando los criterios de sepsis neonatal tardía: propuesta de un algoritmo de vigilancia diagnóstica

Science.gov (United States)

Zea-Vera, Alonso; Turin, Christie G.; Ochoa, Theresa J.

2015-01-01

Las infecciones constituyen una de las principales causas de muerte en el periodo neonatal. El diagnóstico de sepsis neonatal representa un gran desafío ya que los recién nacidos presentan signos clínicos muy inespecíficos y los exámenes auxiliares tienen una baja sensibilidad. Con el objetivo de mejorar el diagnóstico correcto de esta patología proponemos un algoritmo de vigilancia diagnóstica para sepsis neonatal tardía en el Perú y países de la región. El algoritmo permite clasificar a los episodios como sepsis confirmada, probable o posible, y sobretodo busca identificar aquellos episodios que no corresponden a sepsis, evitando calificar otras patologías como “sepsis”. Un mejor diagnóstico permitiría tener tasas más reales de sepsis neonatal, mejorar el uso de antibióticos y evitar sus efectos negativos en el recién nacido, así como una visión más exacta de su impacto en la salud pública. PMID:25123879

High-Temperature High-Efficiency Solar Thermoelectric Generators

Energy Technology Data Exchange (ETDEWEB)

Baranowski, LL; Warren, EL; Toberer, ES

2014-03-01

Inspired by recent high-efficiency thermoelectric modules, we consider thermoelectrics for terrestrial applications in concentrated solar thermoelectric generators (STEGs). The STEG is modeled as two subsystems: a TEG, and a solar absorber that efficiently captures the concentrated sunlight and limits radiative losses from the system. The TEG subsystem is modeled using thermoelectric compatibility theory; this model does not constrain the material properties to be constant with temperature. Considering a three-stage TEG based on current record modules, this model suggests that 18% efficiency could be experimentally expected with a temperature gradient of 1000A degrees C to 100A degrees C. Achieving 15% overall STEG efficiency thus requires an absorber efficiency above 85%, and we consider two methods to achieve this: solar-selective absorbers and thermally insulating cavities. When the TEG and absorber subsystem models are combined, we expect that the STEG modeled here could achieve 15% efficiency with optical concentration between 250 and 300 suns.

Organización del conocimiento de la asignatura “estructuras de datos y algoritmosâ€� para ingeniería informática basada en mapas conceptuales

OpenAIRE

SOLER PELLICER, YOLANDA; LEZCANO BRITO, MATEO GERÓNIMO

2009-01-01

Las asignaturas de Programación y Algoritmos deben lograr que los estudiantes escriban algoritmos eficientes. Ese objetivo se ve afectado por el hecho de que los estudiantes no saben escoger y diseñar las estructuras de datos adecuadas para representar la información. Tomando en cuenta este hecho, el Centro de Estudios de Informática Educativa (C EIE ) de la Universidad de Granma y el Centro de Estudios Informáticos (CEI) de la Universidad Central “Marta Abreuâ€� de Las Villas, Cuba, propon...

IDENTIFICACIÓN EFICIENTE DE ERRORES EN ESTIMACIÓN DE ESTADO USANDO UN ALGORITMO GENÉTICO ESPECIALIZADO IDENTIFICAÇÃO EFICAZ DOS ERROS EM ESTIMATIVA DE ESTADO USANDO UM ALGORITMO GENÉTICO ESPECIALIZADO EFFICIENT IDENTIFICATION OF ERRORS IN STATE ESTIMATION THROUGH A SPECIALIZED GENETIC ALGORITHM

Directory of Open Access Journals (Sweden)

Hugo Andrés Ruiz

2012-06-01

Full Text Available En este artículo se presenta un método para resolver el problema de estimación de estado en sistemas eléctricos usando optimización combinatoria. Su objetivo es el estudio de mediciones con errores de difícil detección, que afectan el desempeño y calidad de los resultados cuando se emplea un estimador de estado clásico. Dada su complejidad matemática, se deducen indicadores de sensibilidad de la teoría de puntos de apalancamiento que se usan en el algoritmo de optimización de Chu-Beasley, con el fin de disminuir el esfuerzo computacional y mejorar la calidad de los resultados. El método propuesto se valida en un sistema IEEE de 30 nodos.Neste artigo apresenta-se um método para resolver o problema de estimativa de estado em sistemas elétricos usando otimização combinatória. Seu objetivo é o estudo de medidas com erros de difícil detecção, que afetam o desempenho e qualidade dos resultados quando se emprega um estimador de estado clássico. Dada sua complexidade matemática, deduzem-se indicadores de sensibilidade da teoria de pontos de alavancagem que se usam no algoritmo de otimização de Chu-Beasley, com o fim de diminuir o esforço computacional e melhorar a qualidade dos resultados. O método proposto se valida em um sistema IEEE de 30 nós.In this paper a method to solve the state estimation problem in electric systems applying combinatorial optimization is presented. Its objective is the study of measures with difficult detection errors, which affect the performance and quality of the results when a classic state estimator is used. Due to the mathematical complexity, sensibility indicators are deduced from the theory of leverage points used in the Chu-Beasley optimization algorithm with the purpose of reducing the computational effort and enhance the quality of the results. The proposed method is validated in a 30-node IEEE system.

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

International Nuclear Information System (INIS)

Kim, Min Soo; Sohn, Jeong Hyun; Kim, Jung Hee; Sung, Yong Jun

2016-01-01

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system

Efficiency Analysis of a Wave Power Generation System by Using Multibody Dynamics

Energy Technology Data Exchange (ETDEWEB)

Kim, Min Soo; Sohn, Jeong Hyun [Pukyong National Univ., Busan (Korea, Republic of); Kim, Jung Hee; Sung, Yong Jun [INGINE Inc., Seoul (Korea, Republic of)

2016-06-15

The energy absorption efficiency of a wave power generation system is calculated as the ratio of the wave power to the power of the system. Because absorption efficiency depends on the dynamic behavior of the wave power generation system, a dynamic analysis of the wave power generation system is required to estimate the energy absorption efficiency of the system. In this study, a dynamic analysis of the wave power generation system under wave loads is performed to estimate the energy absorption efficiency. RecurDyn is employed to carry out the dynamic analysis of the system, and the Morison equation is used for the wave load model. According to the results, the lower the wave height and the shorter the period, the higher is the absorption efficiency of the system.

Potenciando el aprendizaje proactivo con ILIAS&WebQuest: aprendiendo a paralelizar algoritmos con GPUs

OpenAIRE

Santamaría, J.; Espinilla, M.; Rivera, A. J.; Romero, S.

2010-01-01

Arquitectura de Computadores es una asignatura troncal de segundo ciclo de la titulación de Ingeniería de Telecomunicación (P.E. 2004) de la Universidad de Jaén, que desde el curso académico 2009/10 cuenta con una metodología de aprendizaje proactivo para motivar al alumno en la realización de las prácticas. En concreto, se ha abordado la enseñanza de la materia de paralelización de algoritmos haciendo uso de GPUs de tarjetas gráficas convencionales. Además, se ha d...

Algoritmos relax-and-cut para problemas de programação inteira 0-1

OpenAIRE

Victor Fernandes Cavalcante

2008-01-01

Resumo: Uma das principais motivações para o estudo de Otimização Discreta reside no elevado número de problemas do nosso cotidiano representáveis através de modelos de Otimização Inteira e Combinatória. Em particular, muitos destes problemas podem ser formulados com Programação Inteira 0-1, o que desperta especial interesse em técnicas capazes de resolver tais modelos. Dentre as inúmeras formas de solução atualmente disponíveis para problemas desta natureza, os algoritmos baseados na técnica...

Séries temporais de NDVI do sensor SPOT Vegetation e algoritmo SAM aplicados ao mapeamento de cana‑de‑açúcar

Directory of Open Access Journals (Sweden)

Luiz Eduardo Vicente

2012-09-01

Full Text Available O objetivo deste trabalho foi avaliar o mapeamento de área de cana‑de‑açúcar por meio de série temporal, de seis anos de dados do índice de vegetação por diferença normalizada (NDVI, oriundos do sensor Vegetation, a bordo do satélite "système pour l'observation de la Terre" (SPOT. Três classes de cobertura do solo (cana‑de‑açúcar, pasto e floresta, do Estado de São Paulo, foram selecionadas como assinaturas espectro‑temporais de referência, que serviram como membros extremos ("endmembers" para classificação com o algoritmo "spectral angle mapper" (SAM. A partir desta classificação, o mapeamento da área de cana‑de‑açúcar foi realizado com uso de limiares na imagem-regra do SAM, gerados a partir dos valores dos espectros de referência. Os resultados mostram que o algoritmo SAM pode ser aplicado a séries de dados multitemporais de resolução moderada, o que permite eficiente mapeamento de alvo agrícola em escala mesorregional. Dados oficiais de áreas de cana‑de‑açúcar, para as microrregiões paulistas, apresentam boa correlação (r² = 0,8 com os dados obtidos pelo método avaliado. A aplicação do algoritmo SAM mostrou ser útil em análises temporais. As séries temporais de NDVI do sensor SPOT Vegetation podem ser utilizadas para mapeamento da área de cana‑de‑açúcar em baixa resolução.

Um sistema para o ensino e aprendizagem de algoritmos utilizando um companheiro de aprendizagem colaborativo

OpenAIRE

Petry, Patrícia Gerent

2005-01-01

Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-graduação em Ciência da Computação Esta dissertação apresenta um modelo computacional de um sistema de suporte ao ensino e aprendizagem no domínio de algoritmos. O sistema inclui um companheiro de aprendizagem virtual, que utiliza a Modelagem Baseada em Restrições (Constraint-Based Modelling) como forma de representação do conhecimento e raciocínio. Os Sistemas Companheiro de Aprendizagem (...

Selección y evaluación de algoritmos para clasificación de documentos

OpenAIRE

Vergara García, Paula María

2014-01-01

Este trabajo ha consistido en un estudio sobre la clasificación de documentos en castellano, basándose en el estándar IPTC. Para ello se ha utilizado un conjunto de ejemplos formado por documentos previamente etiquetados. Partiendo de los distintos tipos de aprendizaje, los algoritmos de clasificación, las herramientas de las que se disponía para la clasificación y las características de conjunto de ejemplos, se decidió utilizar las librerías proporcionadas por las herramientas Mahout, Had...

Algoritmo distribuido de compresión de datos : Una experiencia comparativa con sockets y PVM

OpenAIRE

Russo, Claudia Cecilia; Ramón, Hugo Dionisio; Anderson, Alfredo; Dirazar, Delio; De Giusti, Armando Eduardo

1996-01-01

Es notoria la importancia actual de la compresión de datos en al transmisión de información en redes, especialmente información multimedial Aspectos como optimización del uso del canal, tiempos de repuesta, seguridad y reducción de tráfico, justifican las tareas de investigación y desarrollo en este tema, así como al evolución de los recursos tecnológicos disponibles para implementar nuevas técnicas. En este contexto, se presentan resultados experimentales obtenidos de un algoritmo de compres...

Algoritmos de visión para la estimación robusta de pose 3D

OpenAIRE

Iglesias García, Marcos

2010-01-01

El desarrollo de nuevos algoritmos en el campo de la visión artificial permite dotar a los robots móviles de una mayor autonomía en su funcionamiento. Si el autómata conoce el espacio que le rodea, es capaz de interactuar con el medio y realizar múltiples tareas. Tradicionalmente, los robots están equipados con microprocesadores, ordenadores a bordo que les permiten procesar la información que reciben y actuar en consecuencia. Sin embargo, carecen de inteligencia, lo que les impide reaccionar...

Efficient Modelling and Generation of Markov Automata

NARCIS (Netherlands)

Koutny, M.; Timmer, Mark; Ulidowski, I.; Katoen, Joost P.; van de Pol, Jan Cornelis; Stoelinga, Mariëlle Ida Antoinette

This paper introduces a framework for the efficient modelling and generation of Markov automata. It consists of (1) the data-rich process-algebraic language MAPA, allowing concise modelling of systems with nondeterminism, probability and Markovian timing; (2) a restricted form of the language, the

Algoritmos de métodos numéricos codificados en lenguaje de programación C++ para la solución de problemas de análisis numérico

OpenAIRE

León Zárate, Elmer Alberto

2014-01-01

La presente investigación tuvo como propósito la elaboración de un sistema computacional en el lenguaje de programación C++ que permita codificar los algoritmos para la solución de problemas de análisis numéricos. Este trabajo de investigación tiene por título: "ALGORITMOS DE MÉTODOS NUMÉRICOS CODIFICADOS EN LENGUAJE DE PROGRAMACION C++ PARA LA SOLUCION DE PROBLEMAS DE ANÁLISIS NUMÉRICO" y ha sido preparado para apoyar la formación de los estudiantes de ciencias e ingeniería, quienes podrán a...

MINIMIZACIÓN DE UNA FUNCIÓN DE ORDEN P MEDIANTE UN ALGORITMO GENÉTICO // MINIMIZING A FUNCTION OF ORDER P USING A GENETIC ALGORITHM

Directory of Open Access Journals (Sweden)

Rómulo Castillo Cárdenas

2013-06-01

Full Text Available In this work we consider the problem OVO (order value optimization. The problem we address is to minimize f with x 2 by a genetic algorithm that by its very nature has the advantage over existing continuous optimization methods, to nd global minimizers. We illustrate the application of this algorithm on examples considered showing its e ectiveness in solving them.// RESUMEN En el presente trabajo consideramos el problema OVO (order value optimization. El problema que abordamos consiste entonces en minimizar f con x 2 por medio de un algoritmo gen etico que por su naturaleza intrínseca tiene la ventaja, sobre métodos de optimización continua existentes, de encontrar minimizadores globales. Ilus- tramos la aplicación de este algoritmo sobre ejemplos considerados mostrando su eficacia en la resolución de los mismos.

Evaluation of the efficiency and fault density of software generated by code generators

Science.gov (United States)

Schreur, Barbara

1993-01-01

Flight computers and flight software are used for GN&C (guidance, navigation, and control), engine controllers, and avionics during missions. The software development requires the generation of a considerable amount of code. The engineers who generate the code make mistakes and the generation of a large body of code with high reliability requires considerable time. Computer-aided software engineering (CASE) tools are available which generates code automatically with inputs through graphical interfaces. These tools are referred to as code generators. In theory, code generators could write highly reliable code quickly and inexpensively. The various code generators offer different levels of reliability checking. Some check only the finished product while some allow checking of individual modules and combined sets of modules as well. Considering NASA's requirement for reliability, an in house manually generated code is needed. Furthermore, automatically generated code is reputed to be as efficient as the best manually generated code when executed. In house verification is warranted.

ALGORITMO DE BÚSQUEDA TABÚ ESPECIALIZADO APLICADO AL DISEÑO DE REDES SECUNDARIAS DE ENERGÍA ELÉCTRICA

Directory of Open Access Journals (Sweden)

Víctor Mario Vélez Marín

Full Text Available En este artículo se presenta una metodología para solucionar el problema del planeamiento de sistemas de distribución secundarios empleando como técnica de solución el algoritmo de Búsqueda Tabú. El problema se formula como un modelo no lineal entero-mixto, en el cual se tienen en cuenta la ubicación y capacidad de nuevos elementos (transformadores de distribución y tramos de red primaria y secundaria, reubicación de transformadores de distribución existentes, aumento de capacidades de elementos existentes, reconfiguración de red secundaria y balance de fases. Adicionalmente, se consideran los costos asociados a la conexión entre red primaria y secundaria y las pérdidas de energía en transformadores. Se emplean dos casos de prueba; en el primero se realizan ensayos comparativos con el algoritmo genético de Chu-Beasley para verificar la eficiencia del método propuesto y, en el segundo, se analizan los resultados obtenidos en un sistema de distribución colombiano. En ambos casos los resultados obtenidos son de gran calidad, lo que respalda lo propuesto en este trabajo.

Algoritmo de programação de máquinas individuais com penalidades distintas de adiantamento e atraso

Directory of Open Access Journals (Sweden)

Emerson C. Colin

2000-06-01

Full Text Available Neste trabalho consideramos o problema de máquina única, com datas de entrega e penalidades de adiantamento e atraso distintas para cada ordem. Considerando que a seqüência seja predefinida, o objetivo a ser alcançado é a minimização da soma das diferenças (adiantamentos ou atrasos penalizadas das ordens. Este trabalho é apresentado como uma generalização do algoritmo de programação de Garey et al. (1988. Através de uma estrutura computacional denominada fila de prioridade, este novo algoritmo permite a elaboração de um programa em tempo O(nlogn, enquanto que o melhor encontrado na literatura atualmente é de tempo O(n².In this work we consider the one machine problem, with distinct due-dates and penalties for earliness and tardiness. For a previously defined sequence, we utilize the sum of weighted lateness (earliness or tardiness as objective function. This work is presented as a generalization of the Garey et al. (1988 scheduling algorithm. Using a computational structure called heap, this algorithm allows a schedule construction in O(nlogn time while the best found in literature runs in O(n².

Evaluation on the Efficiency of Biomass Power Generation Industry in China

Directory of Open Access Journals (Sweden)

Jingqi Sun

2014-01-01

Full Text Available As a developing country with large population, China is facing the problems of energy resource shortage and growing environmental pollution arising from the coal-dominated energy structure. Biomass energy, as a kind of renewable energy with the characteristics of being easy to store and friendly to environment, has become the focus of China’s energy development in the future. Affected by the advanced power generation technology and diversified geography environment, the biomass power generation projects show new features in recent years. Hence, it is necessary to evaluate the efficiency of biomass power generation industry by employing proper method with the consideration of new features. In this paper, the regional difference as a new feature of biomass power generation industry is taken into consideration, and the AR model is employed to modify the zero-weight issue when using data envelopment analysis (DEA method to evaluate the efficiency of biomass power generation industry. 30 biomass power generation enterprises in China are selected as the sample, and the efficiency evaluation is performed. The result can provide some insights into the sustainable development of biomass power generation industry in China.

Efficiency of homopolar generators without ferromagnetic circuit

International Nuclear Information System (INIS)

Kharitonov, V.V.

1982-01-01

E.m.f. and weights of homopolar generators (HG) without a ferromagnetic circuit and of similar generator with a ferromagnetic circuit are compared at equal armature diameters and armature rotative speed. HG without ferromagnetic cuircuit of disk and cylinder types with hot and superconducting excitation winding are considered. Areas of the most reasonable removal of a ferromagnetic circuit in the HG layout are found. The plots of relationships between the e.m.f. and HG weight that permit to estimate the efficiency of ''nonferrite'' HG constructions are presented

Metaheurística algoritmo genético para solução de problemas de planejamento florestal com restrições de integridade Genetic algorithm metaheuristic to solve forest planning problem with integer constraints

Directory of Open Access Journals (Sweden)

Flávio Lopes Rodrigues

2004-04-01

Full Text Available Os objetivos deste trabalho foram desenvolver e testar um algoritmo genético (AG para a solução de problemas de gerenciamento florestal com restrições de integridade. O AG foi testado em quatro problemas, contendo entre 93 e 423 variáveis de decisão, sujeitos às restrições de singularidade, produção mínima e produção máxima, periodicamente. Todos os problemas tiveram como objetivo a maximização do valor presente líquido. O AG foi codificado em ambiente delphi 5.0 e os testes foram realizados em um microcomputador AMD K6II 500 MHZ, com memória RAM de 64 MB e disco rígido de 15GB. O desempenho do AG foi avaliado de acordo com as medidas de eficácia e eficiência. Os valores ou categorias dos parâmetros do AG foram testados e comparados quanto aos seus efeitos na eficácia do algoritmo. A seleção da melhor configuração de parâmetros foi feita com o teste L&O, a 1% de probabilidade, e as análises foram realizadas através de estatísticas descritivas. A melhor configuração de parâmetros propiciou ao AG eficácia média de 94,28%, valor mínimo de 90,01%, valor máximo de 98,48%, com coeficiente de variação de 2,08% do ótimo matemático, obtido pelo algoritmo exato branch and bound. Para o problema de maior porte, a eficiência do AG foi cinco vezes superior à eficiência do algoritmo exato branch and bound. O AG apresentou-se como uma abordagem bastante atrativa para solução de importantes problemas de gerenciamento florestal.The objectives of this work was to develop and test a Genetic Algorithm (GA to solve problems of forest management with integer constraints. GA was tested in five problems containing 93 - 423 decision variables, periodically subject to singularity constraints, minimum and maximum production. The problems had the objective of maximizing the net present value. GA was codified into delphi 5.0 language and the tests were performed in a microcomputer AMD K6II 500 MHZ, with RAM memory of 64 MB

Minimización de una función normal-merit mediante un algoritmo convergente globalmente

Directory of Open Access Journals (Sweden)

Gómez Suárez, M.

1998-01-01

Full Text Available En este trabajo presentamos dos conceptos relacionados con la solución de sistemas de ecuaciones no lineales y con desigualdades. El primer concepto es el de una función normal merit, que resume las propiedades básicas que tienen distintas funciones merit conocidas. El segundo concepto es el de un operador Newtoniano, cuyos valores generalizan el concepto de Hessiana para la función normal merit. Combinando el resultado del método generalizado de Newton con ciertos métodos de primer orden, obtenemos un algoritmo de convergencia global para minimizar funciones normales merit.

Generating power at high efficiency combined cycle technology for sustainable energy production

CERN Document Server

Jeffs, E

2008-01-01

Combined cycle technology is used to generate power at one of the highest levels of efficiency of conventional power plants. It does this through primary generation from a gas turbine coupled with secondary generation from a steam turbine powered by primary exhaust heat. Generating power at high efficiency thoroughly charts the development and implementation of this technology in power plants and looks to the future of the technology, noting the advantages of the most important technical features - including gas turbines, steam generator, combined heat and power and integrated gasification com

Refuerzo de puentes por cambio de esquema estructural: optimización mediante algoritmo genético

OpenAIRE

Valenzuela, Matías A.; Casas Rius, Joan Ramon

2011-01-01

La presente comunicación entrega un estudio detallado del proceso constructivo y de tesado para el refuerzo de puentes con tipología longitudinal de vigas continuas convirtiéndolos en puentes en arco atirantado (tipo network). Se presentan las etapas básicas propuestas en aspectos de construcción, se establecen las hipótesis del estudio de tesado e implementa el método de tesado a partir de la optimización automatizada mediante algoritmos genéticos, definiendo criterios como: variables de ...

High-efficiency photovoltaic technology including thermoelectric generation

Science.gov (United States)

Fisac, Miguel; Villasevil, Francesc X.; López, Antonio M.

2014-04-01

Nowadays, photovoltaic solar energy is a clean and reliable source for producing electric power. Most photovoltaic systems have been designed and built up for use in applications with low power requirements. The efficiency of solar cells is quite low, obtaining best results in monocrystalline silicon structures, with an efficiency of about 18%. When temperature rises, photovoltaic cell efficiency decreases, given that the short-circuit current is slightly increased, and the open-circuit voltage, fill factor and power output are reduced. To ensure that this does not affect performance, this paper describes how to interconnect photovoltaic and thermoelectric technology into a single structure. The temperature gradient in the solar panel is used to supply thermoelectric cells, which generate electricity, achieving a positive contribution to the total balance of the complete system.

Efficient Generation and Selection of Combined Features for Improved Classification

KAUST Repository

Shono, Ahmad N.

2014-05-01

This study contributes a methodology and associated toolkit developed to allow users to experiment with the use of combined features in classification problems. Methods are provided for efficiently generating combined features from an original feature set, for efficiently selecting the most discriminating of these generated combined features, and for efficiently performing a preliminary comparison of the classification results when using the original features exclusively against the results when using the selected combined features. The potential benefit of considering combined features in classification problems is demonstrated by applying the developed methodology and toolkit to three sample data sets where the discovery of combined features containing new discriminating information led to improved classification results.

Efficient second- and third-harmonic radiation generation from relativistic laser-plasma interactions

Energy Technology Data Exchange (ETDEWEB)

Singh, Mamta; Gupta, D. N., E-mail: dngupta@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110 007 (India); Suk, H. [Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 500 712 (Korea, Republic of)

2015-06-15

We propose an idea to enhance the efficiency of second- and third-harmonic generation by considering the amplitude-modulation of the fundamental laser pulse. A short-pulse laser of finite spot size is modeled as amplitude modulated in time. Amplitude-modulation of fundamental laser contributes in quiver velocity of the plasma electrons and produces the strong plasma-density perturbations, thereby increase in current density at second- and third-harmonic frequency. In a result, the conversion efficiency of harmonic generation increases significantly. Power conversion efficiency of harmonic generation process is the increasing function of the amplitude-modulation parameter of the fundamental laser beam. Harmonic power generated by an amplitude modulated laser is many folds higher than the power obtained in an ordinary case.

Efficient second- and third-harmonic radiation generation from relativistic laser-plasma interactions

International Nuclear Information System (INIS)

Singh, Mamta; Gupta, D. N.; Suk, H.

2015-01-01

We propose an idea to enhance the efficiency of second- and third-harmonic generation by considering the amplitude-modulation of the fundamental laser pulse. A short-pulse laser of finite spot size is modeled as amplitude modulated in time. Amplitude-modulation of fundamental laser contributes in quiver velocity of the plasma electrons and produces the strong plasma-density perturbations, thereby increase in current density at second- and third-harmonic frequency. In a result, the conversion efficiency of harmonic generation increases significantly. Power conversion efficiency of harmonic generation process is the increasing function of the amplitude-modulation parameter of the fundamental laser beam. Harmonic power generated by an amplitude modulated laser is many folds higher than the power obtained in an ordinary case

An Efficient Method for Generation of Transgenic Rats Avoiding Embryo Manipulation

Directory of Open Access Journals (Sweden)

Bhola Shankar Pradhan

2016-01-01

Full Text Available Although rats are preferred over mice as an animal model, transgenic animals are generated predominantly using mouse embryos. There are limitations in the generation of transgenic rat by embryo manipulation. Unlike mouse embryos, most of the rat embryos do not survive after male pronuclear DNA injection which reduces the efficiency of generation of transgenic rat by this method. More importantly, this method requires hundreds of eggs collected by killing several females for insertion of transgene to generate transgenic rat. To this end, we developed a noninvasive and deathless technique for generation of transgenic rats by integrating transgene into the genome of the spermatogonial cells by testicular injection of DNA followed by electroporation. After standardization of this technique using EGFP as a transgene, a transgenic disease model displaying alpha thalassemia was successfully generated using rats. This efficient method will ease the generation of transgenic rats without killing the lives of rats while simultaneously reducing the number of rats used for generation of transgenic animal.

Efficient 525 nm laser generation in single or double resonant cavity

Science.gov (United States)

Liu, Shilong; Han, Zhenhai; Liu, Shikai; Li, Yinhai; Zhou, Zhiyuan; Shi, Baosen

2018-03-01

This paper reports the results of a study into highly efficient sum frequency generation from 792 and 1556 nm wavelength light to 525 nm wavelength light using either a single or double resonant ring cavity based on a periodically poled potassium titanyl phosphate crystal (PPKTP). By optimizing the cavity's parameters, the maximum power achieved for the resultant 525 nm laser was 263 and 373 mW for the single and double resonant cavity, respectively. The corresponding quantum conversion efficiencies were 8 and 77% for converting 1556 nm photons to 525 nm photons with the single and double resonant cavity, respectively. The measured intra-cavity single pass conversion efficiency for both configurations was about 5%. The performances of the sum frequency generation in these two configurations was studied and compared in detail. This work will provide guidelines for optimizing the generation of sum frequency generated laser light for a variety of configurations. The high conversion efficiency achieved in this work will help pave the way for frequency up-conversion of non-classical quantum states, such as the squeezed vacuum and single photon states. The proposed green laser source will be used in our future experiments, which includes a plan to generate two-color entangled photon pairs and achieve the frequency down-conversion of single photons carrying orbital angular momentum.

Comparación de algoritmos basados en la criptografía simétrica DES, AES y 3DES

Directory of Open Access Journals (Sweden)

Yuri Tatiana Medina Vargas

2015-12-01

Full Text Available RESUMEN La seguridad es uno los aspectos más desafiantes de la internet y las aplicaciones de red. Las cuales están creciendo muy rápido, por lo que la importancia y el valor de los datos intercambiados a través de Internet u otros tipos de medios están aumentando. De ahí la búsqueda de la mejor solución para ofrecer la protección necesaria contra ataques de intrusos a nuestros datos, junto con la prestación de estos servicios en el tiempo es uno de los temas más interesantes en las comunidades relacionadas con la seguridad. La criptografía es la una de las principales categorías de la seguridad informática que convierte la información de su forma normal en un formato ilegible. Las dos características principales que identifican y diferencian algoritmo de cifrado uno de otro son su capacidad para asegurar los datos protegidos contra ataques y su velocidad y eficiencia en hacerlo. Este artículo ofrece una comparación equitativa de tres algoritmos de criptografía de clave simétrica más comunes: DES, AES y 3DES. ABSTRACT Security is one of the most challenging aspects of the internet and network applications. Which are growing very quickly, so that the importance and value of the data exchanged via the Internet or other media types are increasing. Hence the search for the best solution to provide the necessary protection against attacks by intruders to our data, together with the provision of these services in the time it is one of the most interesting topics in the communities related to security. Cryptography is the one of the major categories of computer security that converts the information from its normal form in an unreadable format the two main characteristics that identify and differentiat encryption algorithm from one another are its ability to ensure the data protected against attacks and their speed and efficiency to do so. This article provides a fair comparison of three algorithms for symmetric key cryptography

Algoritmos GRASP para el equilibrado de líneas con riesgo ergonómico mínimo

OpenAIRE

Bautista Valhondo, Joaquín; Alfaro Pozo, Rocío; Batalla García, Cristina; Llovera Laborda, Sara

2015-01-01

Resumen - Se presenta un problema de equilibrado de líneas de montaje con ciclo compatible y número fijo de estaciones con el objetivo de minimizar el máximo riesgo ergonómico presente en las estaciones de trabajo. Tras la formu lación de un modelo matemático para el problema, se proponen procedimientos GRASP para su resolución. Los procedimientos incorporan un algoritmo greedy para regularizar el riesgo ergonómico así como diferentes tipos de mejora local. De...

Algoritmo de alocação de recursos discretos com análise de envoltória de dados

Directory of Open Access Journals (Sweden)

João Carlos Correia Baptista Soares de Mello

2006-08-01

Full Text Available A alocação de recursos é um dos problemas clássicos abordados pela Pesquisa Operacional. A inserção de modelos de Análise de Envoltória de Dados (DEA nesse contexto traz novas possibilidades de estudo, em especial quando combinada com o uso de algoritmos de programação inteira. Este artigo apresenta um algoritmo para distribuição de recursos discretos usando modelos DEA de forma seqüencial. O método proposto é aplicado no estudo de caso da alocação de vagas docentes na Universidade Federal Fluminense. Os resultados são comparados com aqueles obtidos pela comissão encarregada da distribuição das vagas.The resource allocation is one of the main problems in Operational Research. The use of Data Envelopment Analysis (DEA in this field is a new feature with a great potential, mainly when combined with integer programming problems. This paper presents an algorithm to allocate integer resources using a step-by-step DEA algorithm. We applied the proposed approach to a real case study, which consists in allocating teacher positions in some departments of Universidade Federal Fluminense. We compare the results with those obtained by the official commission.

Broadband and high-efficiency vortex beam generator based on a hybrid helix array.

Science.gov (United States)

Fang, Chaoqun; Wu, Chao; Gong, Zhijie; Zhao, Song; Sun, Anqi; Wei, Zeyong; Li, Hongqiang

2018-04-01

The vortex beam which carries the orbital angular momentum has versatile applications, such as high-resolution imaging, optical communications, and particle manipulation. Generating vortex beams with the Pancharatnam-Berry (PB) phase has drawn considerable attention for its unique spin-to-orbital conversion features. Despite the PB phase being frequency independent, an optical element with broadband high-efficiency circular polarization conversion feature is still needed for the broadband high-efficiency vortex beam generation. In this work, a broadband and high-efficiency vortex beam generator based on the PB phase is built with a hybrid helix array. Such devices can generate vortex beams with arbitrary topological charge. Moreover, vortex beams with opposite topological charge can be generated with an opposite handedness incident beam that propagates backward. The measured efficiency of our device is above 65% for a wide frequency range, with the relative bandwidth of 46.5%.

Regional hospital improves efficiency with co-generation retrofit.

Science.gov (United States)

Knutson, D; Anderson, L

1999-11-01

Feasibility analysis of the co-generation retrofit of the Red Deer Regional Hospital pointed to a reasonable payback of capital cost and increased efficiency in operation of the facility. Budget restrictions nearly stopped the project from proceeding. Innovative construction procedures proposed by the Facility Management Group, in particular, Mr Keith Metcalfe, Director of Maintenance, allowed a worthwhile project to reach successful completion. We feel that this model can perhaps be used by similar facilities in the future to achieve their energy efficiency goals.

Control Adaptativo Fraccionario Optimizado por Algoritmos Genéticos, Aplicado a Reguladores Automáticos de Voltaje

Directory of Open Access Journals (Sweden)

Marco E. Ortiz-Quisbert

2016-10-01

Full Text Available Resumen: En este trabajo se presenta la técnica del control adaptable de orden fraccionario por modelo de referencia (CAOFMR, aplicada a los reguladores automáticos de voltaje (RAV. El artículo se enfoca en el ajuste de las ganancias adaptables y los órdenes de derivación de las leyes de ajuste del controlador CAOFMR, determinados por la minimización de una función criterio definida para el modelo simplificado del RAV, mediante la utilización de la técnica de optimización de algoritmos genéticos (AG. En base a un criterio de evaluación propuesto por otros autores, se realizan comparaciones, por medio de simulaciones, de la técnica de control propuesta con los resultados obtenidos por la técnica de control PID de orden entero (OEPID (Zamani et al., 2009. Se muestra que el controlador CAOFMR con parámetros optimizados por AG, entrega mejores resultados en términos de robustez frente a variaciones en los parámetros del sistema controlado y mejoras en relación a la velocidad de convergencia hacia las señales de referencia del sistema RAV. Abstract: The technique Fractional Order Model Reference Adaptive Control (FOMRAC applied to an Automatic Voltage Regulator (AVR is presented in this paper. The work is focused on tuning the adaptive gains and the derivation order of the adaptive laws of the FOMRAC, determined through the minimization of a criterion function defined for the simplified model of the AVR, by means of the genetic algorithm (GA optimization technique. Based on the criterion function proposed by other authors a simulated comparative study is performed, comparing the proposed methodology with the integer order PID control reported in (Zamani et al., 2009. It is shown that the FOMRAC with parameters optimized by GA provides better results in terms of robustness under parameters variations of the system under control and improvements in the convergence speed of the control error. Palabras clave: Control Adaptativo de

Evaluación del comportamiento de un algoritmo para la secuenciación en un taller de flujo con tiempos dependientes de la secuencia

Directory of Open Access Journals (Sweden)

Adriano da Silva-Carvalho

2010-01-01

Full Text Available En el trabajo se realiza la evaluación del comportamiento de un algoritmo propuesto para la secuenciación en un taller de flujo con tiempos dependientes de la secuencia, utilizando un método híbrido basado en el Algoritmo de Búsqueda del Extremo de una Función de un Código Variable y la metaheurística de Búsqueda Dispersa. Asimismo, se analizan casos obtenidos de la aplicación en un taller mecánico de una industria nacional.In this paper the evaluation of the behaviour of a proposed algorithm is made for the sequence of events in a stream flow in a workshop with dependent moments of the sequence using a hybrid method based on the SEARCH OF THE EXTREME OF A FUNTION OF A VARIABLE CODE ALGORITHM AND THE DISPERSED SEARCH METHOD ALGORITHM In the same way, cases obtained from the application in a workshop of the national mechanical industry are analysed.

Development of the ultra high efficiency thermal power generation facility

Energy Technology Data Exchange (ETDEWEB)

Sano, Toshihiro

2010-09-15

In order to prevent global warming, attention is focused on nuclear power generation and renewable energy such as wind and solar power generation. The electric power suppliers of Japan are aiming to increase the amount of nuclear and non-fossil fuel power generation over 50% of the total power generation by 2020. But this means that the remaining half will still be of thermal power generation using fossil fuel and will still play an important role. Under such circumstances, further efficiency improvement of the thermal power generation and its aggressive implementation is ongoing in Japan.

Cálculo, mediante la aplicación del algoritmo de ajuste por mínimos cuadrados, de los componentes de velocidad para estaciones GNSS continuas

Directory of Open Access Journals (Sweden)

Jorge Moya Zamora

2014-07-01

Full Text Available El cálculo de la velocidad de una estación de observación continua GNSS representa un insumo fundamental en la geodesia moderna. El hecho de determinar la posición de las estaciones GNSS de forma diaria implica que se puedan establecer las series temporales de las estaciones, con base en las cuales se puede obtener información de la influencia de fenómenos que afecten el comportamiento de estas. En este artículo se plantea una descripción del algoritmo de ajuste por mínimos cuadrados adaptado y aplicado a la determinación de los componentes de velocidad de estaciones de observación continua. Además, se aplica este algoritmo para la calcular la velocidad de la estación ETCG, perteneciente al Sistema Geocéntrico para las Américas (SIRGAS.

Thermal efficiency improvements - an imperative for nuclear generating stations

International Nuclear Information System (INIS)

Hassanien, S.; Rouse, S.

1997-01-01

A one and a half percent thermal performance improvement of Ontario Hydro's operating nuclear units (Bruce B, Pickering B, and Darlington) means almost 980 GWh are available to the transmission system (assuming an 80% capacity factor). This is equivalent to the energy consumption of 34,000 electrically-heated homes in Ontario, and worth more than $39 million in revenue to Ontario Hydro Nuclear Generation. Improving nuclear plant thermal efficiency improves profitability (more GWh per unit of fuel) and competitiveness (cost of unit energy), and reduces environmental impact (less spent fuel and nuclear waste). Thermal performance will naturally decrease due to the age of the units unless corrective action is taken. Most Ontario Hydro nuclear units are ten to twenty years old. Some common causes for loss of thermal efficiency are: fouling and tube plugging of steam generators, condensers, and heat exchangers; steam leaks in the condenser due to valve wear, steam trap and drain leaks; deposition, pitting, cracking, corrosion, etc., of turbine blades; inadequate feedwater metering resulting from corrosion and deposition. This paper stresses the importance of improving the nuclear units' thermal efficiency. Ontario Hydro Nuclear has demonstrated energy savings results are achievable and affordable. Between 1994 and 1996, Nuclear reduced its energy use and improved thermal efficiency by over 430,000 MWh. Efficiency improvement is not automatic - strategies are needed to be effective. This paper suggests practical strategies to systematically improve thermal efficiency. (author)

Coal-Powered Electric Generating Unit Efficiency and Reliability Dialogue: Summary Report

Energy Technology Data Exchange (ETDEWEB)

Taylor, Emmanuel [Energetics, Inc., Columbia, MD (United States)

2018-02-01

Coal continues to play a critical role in powering the Nation’s electricity generation, especially for baseload power plants. With aging coal generation assets facing decreased performance due to the state of the equipment, and with challenges exacerbated by the current market pressures on the coal sector, there are opportunities to advance early-stage technologies that can retrofit or replace equipment components. These changes will eventually result in significant improvements in plant performance once further developed and deployed by industry. Research and development in areas such as materials, fluid dynamics, fuel properties and preparation characteristics, and a new generation of plant controls can lead to new components and systems that can help improve the efficiency and reliability of coal-fired power plants significantly, allowing these assets to continue to provide baseload power. Coal stockpiles at electricity generation plants are typically large enough to provide 30 to 60 days of power prior to resupply—significantly enhancing the stability and reliability of the U.S. electricity sector. Falling prices for non-dispatchable renewable energy and mounting environmental regulations, among other factors, have stimulated efforts to improve the efficiency of these coal-fired electric generating units (EGUs). In addition, increased reliance on natural gas and non-dispatchable energy sources has spurred efforts to further increase the reliability of coal EGUs. The Coal Powered EGU Efficiency and Reliability Dialogue brought together stakeholders from across the coal EGU industry to discuss methods for improvement. Participants at the event reviewed performance-enhancing innovations in coal EGUs, discussed the potential for data-driven management practices to increase efficiency and reliability, investigated the impacts of regulatory compliance on coal EGU performance, and discussed upcoming challenges for the coal industry. This report documents the key

Modelo origen destino para estimar el flujo de tráfico usando algoritmos genéticos

OpenAIRE

Aldás S., Milton R.; Flores C., Marco J.; Universidad de Cuenca; Dirección de Investigación de la Universidad de Cuenca; DIUC

2014-01-01

En este trabajo se ha desarrollado un nuevo método basado en Inteligencia Artificial para resolver un problema del matriz origen-destino (O-D) aplicado al caso de una red de tráfico vehicular en la ciudad de Ambato. El método implementado, basado en algoritmos genéticos (AG), resuelve el problema de minimización asociado al problema de matriz O-D. Para validar la técnica, se ha utilizado una red vial correspondiente a la zona del Mercado Modelo en la ciudad de Ambato, que es una zona de alta ...

High voltage generator circuit with low power and high efficiency applied in EEPROM

International Nuclear Information System (INIS)

Liu Yan; Zhang Shilin; Zhao Yiqiang

2012-01-01

This paper presents a low power and high efficiency high voltage generator circuit embedded in electrically erasable programmable read-only memory (EEPROM). The low power is minimized by a capacitance divider circuit and a regulator circuit using the controlling clock switch technique. The high efficiency is dependent on the zero threshold voltage (V th ) MOSFET and the charge transfer switch (CTS) charge pump. The proposed high voltage generator circuit has been implemented in a 0.35 μm EEPROM CMOS process. Measured results show that the proposed high voltage generator circuit has a low power consumption of about 150.48 μW and a higher pumping efficiency (83.3%) than previously reported circuits. This high voltage generator circuit can also be widely used in low-power flash devices due to its high efficiency and low power dissipation. (semiconductor integrated circuits)

Desarrollo de algoritmos de asignación de recursos en redes de acceso PON y TWDM-PON

OpenAIRE

Juárez Estévez, David

2017-01-01

El estudio de investigación realizado y descrito en este Trabajo Fin de Grado (TFG) se ha centrado en el desarrollo de algoritmos de gestión de recursos en redes PON (Passive Optical Network) y TWDM-PON (Time Wavelength Division Multiple Passive Optical Network), cuya arquitectura está implementada en un simulador bajo el entorno de simulación OMNET++. Así pues, inicialmente, se realizó un análisis de las redes de acceso PON, además del entorno de trabajo sobre el cual se iba a realizar es...

Obstáculos epistemológicos en la enseñanza de estructura de datos y algoritmos

OpenAIRE

Pérez, Daniel; Aguirre, Sofía; Filippi, José Luis

2016-01-01

[4 p.] il. Los obstáculos epistemológicos bajo la forma de saber-cristalizado generan una suerte de inercia que dificulta el proceso de construcción de un nuevo saber. Su abordaje es necesario para minimizar su impacto negativo y lograr mejoras en los procesos de enseñanza y aprendizaje. El objetivo de este trabajo es identificar los obstáculos que impiden a los alumnos de Estructura de datos y algoritmos de la Facultad de Ingeniería de la Universidad Nacional de La Pampa resolver satis...

Macroporous Double-Network Hydrogel for High-Efficiency Solar Steam Generation Under 1 sun Illumination.

Science.gov (United States)

Yin, Xiangyu; Zhang, Yue; Guo, Qiuquan; Cai, Xiaobing; Xiao, Junfeng; Ding, Zhifeng; Yang, Jun

2018-04-04

Solar steam generation is one of the most promising solar-energy-harvesting technologies to address the issue of water shortage. Despite intensive efforts to develop high-efficiency solar steam generation devices, challenges remain in terms of the relatively low solar thermal efficiency, complicated fabrications, high cost, and difficulty in scaling up. Herein, a double-network hydrogel with a porous structure (p-PEGDA-PANi) is demonstrated for the first time as a flexible, recyclable, and efficient photothermal platform for low-cost and scalable solar steam generation. As a novel photothermal platform, the p-PEGDA-PANi involves all necessary properties of efficient broadband solar absorption, exceptional hydrophilicity, low heat conductivity, and porous structure for high-efficiency solar steam generation. As a result, the hydrogel-based solar steam generator exhibits a maximum solar thermal efficiency of 91.5% with an evaporation rate of 1.40 kg m -2 h -1 under 1 sun illumination, which is comparable to state-of-the-art solar steam generation devices. Furthermore, the good durability and environmental stability of the p-PEGDA-PANi hydrogel enables a convenient recycling and reusing process toward real-life applications. The present research not only provides a novel photothermal platform for solar energy harvest but also opens a new avenue for the application of the hydrogel materials in solar steam generation.

Highly efficient single-pass sum frequency generation by cascaded nonlinear crystals

DEFF Research Database (Denmark)

Hansen, Anders Kragh; Andersen, Peter E.; Jensen, Ole Bjarlin

2015-01-01

, despite differences in the phase relations of the involved fields. An unprecedented 5.5 W of continuous-wave diffraction-limited green light is generated from the single-pass sum frequency mixing of two diode lasers in two periodically poled nonlinear crystals (conversion efficiency 50%). The technique......The cascading of nonlinear crystals has been established as a simple method to greatly increase the conversion efficiency of single-pass second-harmonic generation compared to a single-crystal scheme. Here, we show for the first time that the technique can be extended to sum frequency generation...... is generally applicable and can be applied to any combination of fundamental wavelengths and nonlinear crystals....

Design and optimization of automotive thermoelectric generators for maximum fuel efficiency improvement

International Nuclear Information System (INIS)

Kempf, Nicholas; Zhang, Yanliang

2016-01-01

Highlights: • A three-dimensional automotive thermoelectric generator (TEG) model is developed. • Heat exchanger design and TEG configuration are optimized for maximum fuel efficiency increase. • Heat exchanger conductivity has a strong influence on maximum fuel efficiency increase. • TEG aspect ratio and fin height increase with heat exchanger thermal conductivity. • A 2.5% fuel efficiency increase is attainable with nanostructured half-Heusler modules. - Abstract: Automotive fuel efficiency can be increased by thermoelectric power generation using exhaust waste heat. A high-temperature thermoelectric generator (TEG) that converts engine exhaust waste heat into electricity is simulated based on a light-duty passenger vehicle with a 4-cylinder gasoline engine. Strategies to optimize TEG configuration and heat exchanger design for maximum fuel efficiency improvement are provided. Through comparison of stainless steel and silicon carbide heat exchangers, it is found that both the optimal TEG design and the maximum fuel efficiency increase are highly dependent on the thermal conductivity of the heat exchanger material. Significantly higher fuel efficiency increase can be obtained using silicon carbide heat exchangers at taller fins and a longer TEG along the exhaust flow direction when compared to stainless steel heat exchangers. Accounting for major parasitic losses, a maximum fuel efficiency increase of 2.5% is achievable using newly developed nanostructured bulk half-Heusler thermoelectric modules.

ESCENARIOS PARA LA UBICACIÓN ÓPTIMA DE GENERACIÓN DISTRIBUIDA CON BASE EN UN ALGORITMO ANALÍTICO

Directory of Open Access Journals (Sweden)

Diego Leonardo González Herrera

2013-09-01

Full Text Available En este artículo se presentan los escenarios de simulación planteados en base a un algoritmo analítico para la ubicación de la generación distribuida. En primera instancia se hace un recorrido por el estado del arte referente a los factores involucrados en la planeación de la demanda  y estudios de cortocircuito. Así mismo, se exhibe la propuesta metodológica para evaluar el impacto y algunos resultados preliminares obtenidos.

Algoritmo genético aplicado a la programación en talleres de maquinado//Genetic algorithm applied to scheduling in machine shops

Directory of Open Access Journals (Sweden)

José Eduardo Márquez-Delgado

2012-09-01

Full Text Available En este trabajo se utiliza la metaheurística nombrada algoritmo genético, para dos variantes típicas de problemas de planificación presentes en un taller de maquinado de piezas: las variantes flujo general y flujo regular, y se ha seleccionado la minimización del tiempo de finalización de todos los trabajos ocamino máximo, como objetivo a optimizar en un plan de trabajo. Este problema es considerado de difícil solución y es típico de la optimización combinatoria. Los resultados demuestran la calidad de las soluciones encontradas en correspondencia con el tiempo de cómputo empleado, al ser comparados conproblemas clásicos reportados por otros autores. La representación propuesta de cada cromosoma genera el universo completo de soluciones factibles, donde es posible encontrar valores óptimos globales de solución y cumple con las restricciones del problema.Palabras claves: algoritmo genético, cromosomas, flujo general, flujo regular, planificación, camino máximo._____________________________________________________________________________AbstractIn this paper we use the metaheuristic named genetic algorithm, for two typical variants of problems of scheduling present in a in a machine shop parts: the variant job shop and flow shop, and the minimization of the time of finalization of all the works has been selected, good known as makespan, as objective tooptimize in a work schedule. This problem is considered to be a difficult solution and is typical in combinatory optimization. The results demonstrate the quality of the solutions found in correspondence with the time of used computation, when being compared with classic problems reported by other authors.The proposed representation of each chromosome generates the complete universe of feasible solutions, where it is possible to find global good values of solution and it fulfills the restrictions of the problem.Key words: genetic algorithm, chromosomes, flow shop, job shop

Wavelength dependence of the efficiency of singlet oxygen generation upon photoexcitation of photosensitizers

Directory of Open Access Journals (Sweden)

Starukhin A.

2017-01-01

Full Text Available The dependence of the efficiency of singlet oxygen (1Δg generation upon excitation of photosensitizer at different wavelength was observed for several derivatives of palladium porphyrin in carbon tetrachloride. The efficiency of singlet oxygen generation upon excitation in a blue region of the spectrum (Soret band exceeds by several times the efficiency at excitation in the red spectral region (Q band. The effect of enhancement of singlet oxygen generation upon CW photoexcitation to Soret band of photosensitizer may be explained by influence of high laying triplet states of a donor molecule on the triplet-triplet energy transfer.

Desarrollo de un algoritmo en MATLAB para la optimización de la resolución de una tarjeta USRP B210 para aplicaciones SDRadar

Directory of Open Access Journals (Sweden)

David Moreno Avilés

2017-11-01

Full Text Available En este documento se analizan las limitaciones y características que tiene la tarjeta USRP (Universal Software Radio Peripheral B210 para desarrollar aplicaciones de radar definidos por software (SDRadar. Para el desarrollo del algoritmo se utilizó un radar de onda continua modulada en frecuencia (FMCW que implementa una señal chirp, al considerar que 25 MHz es el máximo ancho de banda que la tarjeta puede proporcionar se obtiene como resultado una resolución de 6 metros. El método utilizado para optimizar la resolución de la tarjeta fue transmitir un determinado número de señales con distintos anchos de banda, lo que resulta en una resolución diferente, al detectar y almacenar el objetivo en una matriz. Después de las pruebas correspondientes el algoritmo estableció que con 14 mediciones con variaciones de ancho de banda de 0.5 MHz, entre cada señal, se obtiene la mayor optimización para mejorar la resolución de la tarjeta. Se obtuvo finalmente dos zonas de optimización, donde la primera zona está limitada por un error de medición menor a 1 metro, y en la segunda zona con un error de medición entre 1 y 2 metros con 69.15% y 30.85% de objetivos detectados respectivamente, lo que determina su efectividad y confiabilidad. Este trabajo ha demostrado que el algoritmo utilizado es útil en aplicaciones SDRadar para detectar objetivos para aplicaciones topográficas o sistemas SAR.

Composición Musical a Través del Uso de Algoritmos Genéticos

Directory of Open Access Journals (Sweden)

Ezequiel Moldaver

2014-06-01

Full Text Available Este trabajo se enfocará en el uso de los algoritmos genéticos (AAGG con el fin de mezclar armonías y melodías de forma que se genere una composición musical de buen sonido para el oído, lo que significa que el contexto de cada nota respaldará la sonoridad de la misma provocando que no se genere un efecto disonante de forma permanente, que se genere una disonancia momentánea es permisible ya que es parte de la misma música generar tensión a través de pequeños intervalos poco agradables al oído.

Biomass Gasification for Power Generation Internal Combustion Engines. Process Efficiency

International Nuclear Information System (INIS)

Lesme-Jaén, René; Garcia-Faure, Luis; Oliva-Ruiz, Luis; Pajarín-Rodríguez, Juan; Revilla-Suarez, Dennis

2016-01-01

Biomass is a renewable energy sources worldwide greater prospects for its potential and its lower environmental impact compared to fossil fuels. By different processes and energy conversion technologies is possible to obtain solid, liquid and gaseous fuels from any biomass.In this paper the evaluation of thermal and overall efficiency of the gasification of Integral Forestry Company Santiago de Cuba is presented, designed to electricity generation from waste forest industry. The gasifier is a downdraft reactor, COMBO-80 model of Indian manufacturing and motor (diesel) model Leyland modified to work with producer gas. The evaluation was conducted at different loads (electric power generated) of the motor from experimental measurements of flow and composition of gas supplied to the engine. The results show that the motor operates with a thermal efficiency in the range of 20-32% with an overall efficiency between 12-25 %. (author)

Uso de algoritmo de otimização na determinação de tipos de animal funcional Use of optimization algorithm for determining of animal functional types

Directory of Open Access Journals (Sweden)

Carlos Eduardo Nogueira Martins

2012-08-01

Full Text Available O presente trabalho teve como objetivo avaliar o uso de algoritmo de otimização na determinação de tipos funcionais de animais da raça Braford para diferentes condições ambientais. Foram utilizados algoritmos específicos de otimização por meio do progama computacional SYNCSA, com o objetivo de determinar subconjuntos ótimos de atributos que definem diferentes tipos funcionais, tendo em vista a eficiência de utilização da pastagem pelos animais. Tais algoritmos estão fundamentados na definição de matrizes de incidência que relacionam as variáveis de interesse. No presente estudo, a matriz B definiu a relação animais x medidas corporais; a matriz W, a relação produtividade acumulada x graus de sangue; e a matriz E, a relação graus de sangue x ambientes (com e sem restrição alimentar. Os resultados mostraram a existência de três tipos funcionais: animais de maior estrutura corporal; animais de estrutura intermediária e animais com menor estrutura, com exceção do atributo largura do peito. Os animais de maior estrutura corporal obtiveram 30 e 47,7kg a mais de terneiros desmamados, no ambiente sem restrição alimentar, que os animais de estrutura corporal média e pequena, respectivamente. No ambiente com restrição alimentar, o tipo de animal de estrutura média apresentou melhor desempenho produtivo, sendo este 18,5 e 36,8% superior aos tipos de maior e menor estrutura corporal, respectivamente. Os resultados deste trabalho demonstram que o algoritmo criado para determinação de tipos funcionais pode ser utilizado na busca do melhor biótipo animal para os diferentes sistemas de produção.This study aimed to evaluate the use of optimization algorithm to determine functional types of animals Braford for different environmental conditions. We used specific optimization algorithms through the computer program SYNCSA in order to determine optimal subsets of attributes that define different functional types in view

Paralelización de un algoritmo de compresión que utiliza diccionario estático

OpenAIRE

Ramón, Hugo Dionisio; Russo, Claudia Cecilia; Anderson, Alfredo; De Giusti, Armando Eduardo; Dirazar, Delio

1996-01-01

Es notoria la importancia creciente de la compresión de datos en la transmisión de información en redes. Aspectos como seguridad, reducción de tráfico, optimización del uso del canal, étc., justifican las tareas deinvestigación y desarrollo en este tema, así como la evolución de los recursos tecnológicos disponibles. En particular, por el volumen de información en juego, en los últimos años hay un esfuerzo muy notorio en la optimización de algoritmos para compresión de datos utilizando difere...

PSAL : estudio, análisis e implementación de algoritmos de síntesis de alto nivel

OpenAIRE

Sánchez Espeso, Pablo Pedro

2011-01-01

En los últimos años se ha producido un gran avance en el desarrollo de herramientas de diseño asistido por computador (cad) en microelectrónica, motivado en gran medida por la creciente complejidad de los circuitos integrados digitales. Este proceso ha incidido principalmente en la automatización del diseño desde el nivel lógico al layout, mientras que las etapas iniciales (especificación del algoritmo y determinación de la arquitectura) siguen dependiendo del diseñador. En la presente tes...

Algoritmo eficiente para cálculo de mapas de visibilidade em terrenos armazenados em memória externa

OpenAIRE

Magalhães, Mirella Antunes de

2009-01-01

Com a maior disponibilidade de dados detalhados de terrenos, muitas aplicações precisam processar grandes áreas geográficas em alta resolução. O processamento massivo de dados envolvido em tais aplicações criou grandes desafios para os SIGs e necessita de algoritmos otimizados tanto para processamento interno quanto para transferência de dados. Uma dessas aplicações é o cálculo de mapas de visibilidade ou viewshed, que consiste em obter o conjunto de pontos visíveis a partir de um ponto p. Ne...

Algoritmos de deteção de comportamento de indivíduos com autismo: análise comparativa

OpenAIRE

Ferreira, Miguel Proença Brás

2013-01-01

A elevada prevalência de doenças relacionadas com o autismo e a necessidade de descoberta desta patologia de difícil diagnóstico e convivência, levou a que seja imprescindível o desenvolvimento de mecanismos de deteção e avaliação da atividade de pacientes. Esta tese tem como principal objetivo colmatar estas necessidades. Os algoritmos testados são direcionados à melhoria da monitorização de doentes com autismo e com necessidades especiais. Estes têm ...

Probabilistic Forecasting of Photovoltaic Generation: An Efficient Statistical Approach

DEFF Research Database (Denmark)

Wan, Can; Lin, Jin; Song, Yonghua

2017-01-01

This letter proposes a novel efficient probabilistic forecasting approach to accurately quantify the variability and uncertainty of the power production from photovoltaic (PV) systems. Distinguished from most existing models, a linear programming based prediction interval construction model for P...... power generation is proposed based on extreme learning machine and quantile regression, featuring high reliability and computational efficiency. The proposed approach is validated through the numerical studies on PV data from Denmark.......This letter proposes a novel efficient probabilistic forecasting approach to accurately quantify the variability and uncertainty of the power production from photovoltaic (PV) systems. Distinguished from most existing models, a linear programming based prediction interval construction model for PV...

ALGORITMO PARA DISEÑAR LÍNEAS DE TRANSMISIÓN CON CABLES PROTECTORES SEGMENTADOS

Directory of Open Access Journals (Sweden)

Héctor Silvio Llamo Laborí

2011-02-01

Full Text Available En las líneas de transmisión a voltajes de 220 kV y mayores, el valor de las pérdidas en loscables protectores puede justificar económicamente su segmentación para reducirlas a cero.Se presentan los resultados y las características de un algoritmo para diseñar o comprobar eldiseño de esquemas de cables protectores segmentados a partir de calcular el voltaje máximoinducido electromagnéticamente en los mismos.  In the 220 kV and higher transmission lines, the lost value in the ground wires can justifieseconomically its segmentation to reduce it to zero.Are presented the characteristics and results of an algorithm to design or test the schemesof segmented ground wires calculating the electromagnetic voltage induced on it.

Algoritmo de actuación en la prevención de la mutilación genital femenina. Estudio de casos desde atención primaria

Directory of Open Access Journals (Sweden)

Carolina Alcón Belchí

2016-03-01

Conclusión: El algoritmo diseñado orienta a los profesionales en su actuación, consiguiendo una eficaz detección y prevención de mutilación genital de las niñas y resulta una primera aproximación para el desarrollo de un protocolo regional.

High-efficiency ballistic electrostatic generator using microdroplets

Science.gov (United States)

Xie, Yanbo; Bos, Diederik; de Vreede, Lennart J.; de Boer, Hans L.; van der Meulen, Mark-Jan; Versluis, Michel; Sprenkels, Ad J.; van den Berg, Albert; Eijkel, Jan C. T.

2014-04-01

The strong demand for renewable energy promotes research on novel methods and technologies for energy conversion. Microfluidic systems for energy conversion by streaming current are less known to the public, and the relatively low efficiencies previously obtained seemed to limit the further applications of such systems. Here we report a microdroplet-based electrostatic generator operating by an acceleration-deceleration cycle (‘ballistic’ conversion), and show that this principle enables both high efficiency and compact simple design. Water is accelerated by pumping it through a micropore to form a microjet breaking up into fast-moving charged droplets. Droplet kinetic energy is converted to electrical energy when the charged droplets decelerate in the electrical field that forms between membrane and target. We demonstrate conversion efficiencies of up to 48%, a power density of 160 kW m-2 and both high- (20 kV) and low- (500 V) voltage operation. Besides offering striking new insights, the device potentially opens up new perspectives for low-cost and robust renewable energy conversion.

Analysis of entropy extraction efficiencies in random number generation systems

Science.gov (United States)

Wang, Chao; Wang, Shuang; Chen, Wei; Yin, Zhen-Qiang; Han, Zheng-Fu

2016-05-01

Random numbers (RNs) have applications in many areas: lottery games, gambling, computer simulation, and, most importantly, cryptography [N. Gisin et al., Rev. Mod. Phys. 74 (2002) 145]. In cryptography theory, the theoretical security of the system calls for high quality RNs. Therefore, developing methods for producing unpredictable RNs with adequate speed is an attractive topic. Early on, despite the lack of theoretical support, pseudo RNs generated by algorithmic methods performed well and satisfied reasonable statistical requirements. However, as implemented, those pseudorandom sequences were completely determined by mathematical formulas and initial seeds, which cannot introduce extra entropy or information. In these cases, “random” bits are generated that are not at all random. Physical random number generators (RNGs), which, in contrast to algorithmic methods, are based on unpredictable physical random phenomena, have attracted considerable research interest. However, the way that we extract random bits from those physical entropy sources has a large influence on the efficiency and performance of the system. In this manuscript, we will review and discuss several randomness extraction schemes that are based on radiation or photon arrival times. We analyze the robustness, post-processing requirements and, in particular, the extraction efficiency of those methods to aid in the construction of efficient, compact and robust physical RNG systems.

Efficient steam generation by inexpensive narrow gap evaporation device for solar applications.

Science.gov (United States)

Morciano, Matteo; Fasano, Matteo; Salomov, Uktam; Ventola, Luigi; Chiavazzo, Eliodoro; Asinari, Pietro

2017-09-20

Technologies for solar steam generation with high performance can help solving critical societal issues such as water desalination or sterilization, especially in developing countries. Very recently, we have witnessed a rapidly growing interest in the scientific community proposing sunlight absorbers for direct conversion of liquid water into steam. While those solutions can possibly be of interest from the perspective of the involved novel materials, in this study we intend to demonstrate that efficient steam generation by solar source is mainly due to a combination of efficient solar absorption, capillary water feeding and narrow gap evaporation process, which can also be achieved through common materials. To this end, we report both numerical and experimental evidence that advanced nano-structured materials are not strictly necessary for performing sunlight driven water-to-vapor conversion at high efficiency (i.e. ≥85%) and relatively low optical concentration (≈10 suns). Coherently with the principles of frugal innovation, those results unveil that solar steam generation for desalination or sterilization purposes may be efficiently obtained by a clever selection and assembly of widespread and inexpensive materials.

Algoritmo para Estimar los Saldos Netos Migratorios en entidades federativas mexicanas

Directory of Open Access Journals (Sweden)

Elmyra YBÁÑEZ-ZEPEDA

2015-01-01

Full Text Available En este artículo se describe el diseño, desarrollo e implementación de un Algoritmo para Estimar Saldos Netos Migratorios (ASNM en las entidades federativas de México mediante un modelo de distribución territorial de la población de Rogers en el que a través de la matriz de origendestino de la migración interna se incluyen el comportamiento del crecimiento natural y el de la inmigración y emigración internacional. Los datos requeridos son totalmente de base demográfica. Se buscó respetar al dato para que él hable por sí mismo a través de un modelo que le permita expresarse. Los resultados indican que de acuerdo con las cifras observadas por el censo de 2010 y a las estimadas por el ASNM para 2015, la contribución anual del SNM al total de la población por entidad federativa no representa más de tres por ciento.

Algoritmo PSO para identificación de parámetros en un motor DC

Directory of Open Access Journals (Sweden)

César Duarte

2010-01-01

Full Text Available En este artículo se presenta la aplicación del algoritmo Particle Swarm Optimization (PSO como estrategia de búsqueda para determinar los parámetros de un sistema tipo caja gris. Este proceso de identificación se ilustra utilizando la respuesta a un escalón de un motor DC en lazo abierto. Para agilizar la identificación del sistema a través del uso de PSO, se limita el espacio de búsqueda usando la información que puede extraerse de la respuesta en el dominio del tiempo del sistema a identificar. Los resultados del proceso de identificación de los parámetros del motor se obtienen utilizando la herramienta PSOt disponible para entorno Matlab® desarrollada por Brian Birge.

Paradigma. Hacia el diseño y desarrollo de algoritmos y sistemas de control para clonación artificial en procesos industriales.

Directory of Open Access Journals (Sweden)

Jairo Amador

2004-11-01

Full Text Available Haciendo uso de Ia tecnología inteligente basada en la lógica difusa, las redes neuronales y los algoritmos genéticos, se pretende plantear un paradigma para la clonación artificial de dispositivos en procesos industriales, específicamente para sensores, los cuales deberán replicar las mismas o mejores funciones de los dispositivos reales mediante la evolución des comportamiento.

Efficient Modelling and Generation of Markov Automata (extended version)

NARCIS (Netherlands)

Timmer, Mark; Katoen, Joost P.; van de Pol, Jan Cornelis; Stoelinga, Mariëlle Ida Antoinette

2012-01-01

This paper introduces a framework for the efficient modelling and generation of Markov automata. It consists of (1) the data-rich process-algebraic language MAPA, allowing concise modelling of systems with nondeterminism, probability and Markovian timing; (2) a restricted form of the language, the

Super Boiler: First Generation, Ultra-High Efficiency Firetube Boiler

Energy Technology Data Exchange (ETDEWEB)

None

2006-06-01

This factsheet describes a research project whose goal is to develop and demonstrate a first-generation ultra-high-efficiency, ultra-low emissions, compact gas-fired package boiler (Super Boiler), and formulate a long-range RD&D plan for advanced boiler technology out to the year 2020.

Efficient femtosecond mid-infrared pulse generation by dispersivewave radiation in bulk lithium niobate crystal

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2014-01-01

We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm.......We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8–2.92 µm are generated using the single pump wavelengths from 1.25–1.45 µm....

Nossa experiência com a paralelizâçao de um algoritmo de processamento de imagens geográficas

OpenAIRE

Shishido, Henrique Yoshikazu; Silva, Anderson Faustino da; Gonçalves, Ronaldo Augusto de Lara; Batista, Ligia Flavia Antunes

2010-01-01

O processamento de imagem digital tem sido usado em diversas áreas de pesquisa como instrumento para o reconhecimento de padres e de filtragens específicas nas imagens. Entretanto, dependendo das características da aplicação o tempo de processamento pode ser extremamente alto e dificultar o avanço das pesquisas associadas. Nesse contexto, este trabalho propõe a paralelização de um algoritmo para o processamento de imagem digital utilizado no cálculo de índice de fragmentação multidimensional....

Efficient heat generation in large-area graphene films by electromagnetic wave absorption

Science.gov (United States)

Kang, Sangmin; Choi, Haehyun; Lee, Soo Bin; Park, Seong Chae; Park, Jong Bo; Lee, Sangkyu; Kim, Youngsoo; Hong, Byung Hee

2017-06-01

Graphene has been intensively studied due to its outstanding electrical and thermal properties. Recently, it was found that the heat generation by Joule heating of graphene is limited by the conductivity of graphene. Here we suggest an alternative method to generate heat on a large-area graphene film more efficiently by utilizing the unique electromagnetic (EM) wave absorption property of graphene. The EM wave induces an oscillating magnetic moment generated by the orbital motion of moving electrons, which efficiently absorbs the EM energy and dissipate it as a thermal energy. In this case, the mobility of electron is more important than the conductivity, because the EM-induced diamagnetic moment is directly proportional to the speed of electron in an orbital motion. To control the charge carrier mobility of graphene we functionalized substrates with self-assembled monolayers (SAM). As the result, we find that the graphene showing the Dirac voltage close to zero can be more efficiently heated by EM waves. In addition, the temperature gradient also depends on the number of graphene. We expect that the efficient and fast heating of graphene films by EM waves can be utilized for smart heating windows and defogging windshields.

Efficient generation of pronunciation dictionaries: human factors factors during bootstrapping

CSIR Research Space (South Africa)

Davel, MH

2004-10-01

Full Text Available Bootstrapping techniques have significant potential for the efficient generation of linguistic resources such as electronic pronunciation dictionaries. The authors describe a system and an approach to bootstrapping for the development...

Industry perspectives on increasing the efficiency of coal-fired power generation

Energy Technology Data Exchange (ETDEWEB)

Torrens, I.M. [Shell Coal International, London (United Kingdom); Stenzel, W.C.

1997-12-31

Independent power producers will build a substantial fraction of expected new coal-fired power generation in developing countries over the coming decades. To reduce perceived risk and obtain financing for their projects, they are currently building and plan to continue to build subcritical coal-fired plants with generating efficiency below 40%. Up-to-date engineering assessment leads to the conclusion that supercritical generating technology, capable of efficiencies of up to 45%, can produce electricity at a lower total cost than conventional plants. If such plants were built in Asia over the coming decades, the savings in carbon dioxide emissions over their lifetime would be measured in billions of tons. IPPs perceive supercritical technology as riskier and higher cost than conventional technology. The truth needs to be confirmed by discussions with additional experienced power engineering companies. Better communication among the interested parties could help to overcome the IPP perception issue. Governments working together with industry might be able to identify creative financing arrangements which can encourage the use of more efficient pulverized clean coal technologies, while awaiting the commercialization of advanced clean coal technologies like gasification combined cycle and pressurized fluidized bed combustion.

Lightweight, Mesoporous, and Highly Absorptive All-Nanofiber Aerogel for Efficient Solar Steam Generation.

Science.gov (United States)

Jiang, Feng; Liu, He; Li, Yiju; Kuang, Yudi; Xu, Xu; Chen, Chaoji; Huang, Hao; Jia, Chao; Zhao, Xinpeng; Hitz, Emily; Zhou, Yubing; Yang, Ronggui; Cui, Lifeng; Hu, Liangbing

2018-01-10

The global fresh water shortage has driven enormous endeavors in seawater desalination and wastewater purification; among these, solar steam generation is effective in extracting fresh water by efficient utilization of naturally abundant solar energy. For solar steam generation, the primary focus is to design new materials that are biodegradable, sustainable, of low cost, and have high solar steam generation efficiency. Here, we designed a bilayer aerogel structure employing naturally abundant cellulose nanofibrils (CNFs) as basic building blocks to achieve sustainability and biodegradability as well as employing a carbon nanotube (CNT) layer for efficient solar utilization with over 97.5% of light absorbance from 300 to 1200 nm wavelength. The ultralow density (0.0096 g/cm 3 ) of the aerogel ensures that minimal material is required, reducing the production cost while at the same time satisfying the water transport and thermal-insulation requirements due to its highly porous structure (99.4% porosity). Owing to its rationally designed structure and thermal-regulation performance, the bilayer CNF-CNT aerogel exhibits a high solar-energy conversion efficiency of 76.3% and 1.11 kg m -2 h -1 at 1 kW m -2 (1 Sun) solar irradiation, comparable or even higher than most of the reported solar steam generation devices. Therefore, the all-nanofiber aerogel presents a new route for designing biodegradable, sustainable, and scalable solar steam generation devices with superb performance.

Efficient Generation and Selection of Combined Features for Improved Classification

KAUST Repository

Shono, Ahmad N.

2014-01-01

This study contributes a methodology and associated toolkit developed to allow users to experiment with the use of combined features in classification problems. Methods are provided for efficiently generating combined features from an original

Efficiency of Choice Set Generation Methods for Bicycle Routes

DEFF Research Database (Denmark)

Halldórsdóttir, Katrín; Rieser-Schüssler, Nadine; W. Axhausen, Kay

behaviour, observed choices and alternatives composing the choice set of each cyclist are necessary. However, generating the alternative choice sets can prove challenging. This paper analyses the efficiency of various choice set generation methods for bicycle routes in order to contribute to our...... travelling information with GPS loggers, compared to self-reported RP data, is more accurate geographic locations and routes. Also, the GPS traces give more reliable information on times and prevent trip underreporting, and it is possible to collect information on many trips by the same person without...

Efficient Raman generation in a waveguide: A route to ultrafast quantum random number generation

Energy Technology Data Exchange (ETDEWEB)

England, D. G.; Bustard, P. J.; Moffatt, D. J.; Nunn, J.; Lausten, R.; Sussman, B. J., E-mail: ben.sussman@nrc.ca [National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A 0R6 (Canada)

2014-02-03

The inherent uncertainty in quantum mechanics offers a source of true randomness which can be used to produce unbreakable cryptographic keys. We discuss the development of a high-speed random number generator based on the quantum phase fluctuations in spontaneously initiated stimulated Raman scattering (SISRS). We utilize the tight confinement and long interaction length available in a Potassium Titanyl Phosphate waveguide to generate highly efficient SISRS using nanojoule pulse energies, reducing the high pump power requirements of the previous approaches. We measure the random phase of the Stokes output using a simple interferometric setup to yield quantum random numbers at 145 Mbps.

Improvement of force factor of magnetostrictive vibration power generator for high efficiency

International Nuclear Information System (INIS)

Kita, Shota; Ueno, Toshiyuki; Yamada, Sotoshi

2015-01-01

We develop high power magnetostrictive vibration power generator for battery-free wireless electronics. The generator is based on a cantilever of parallel beam structure consisting of coil-wound Galfenol and stainless plates with permanent magnet for bias. Oscillating force exerted on the tip bends the cantilever in vibration yields stress variation of Galfenol plate, which causes flux variation and generates voltage on coil due to the law of induction. This generator has advantages over conventional, such as piezoelectric or moving magnet types, in the point of high efficiency, highly robust, and low electrical impedance. Our concern is the improvement of energy conversion efficiency dependent on the dimension. Especially, force factor, the conversion ratio of the electromotive force (voltage) on the tip velocity in vibration, has an important role in energy conversion process. First, the theoretical value of the force factor is formulated and then the validity was verified by experiments, where we compare four types of prototype with parameters of the dimension using 7.0 × 1.5 × 50 mm beams of Galfenol with 1606-turn wound coil. In addition, the energy conversion efficiency of the prototypes depending on load resistance was measured. The most efficient prototype exhibits the maximum instantaneous power of 0.73 W and energy of 4.7 mJ at a free vibration of frequency of 202 Hz in the case of applied force is 25 N. Further, it was found that energy conversion efficiency depends not only on the force factor but also on the damping (mechanical loss) of the vibration

Efficient generation of single and entangled photons on a silicon photonic integrated chip

International Nuclear Information System (INIS)

Mower, Jacob; Englund, Dirk

2011-01-01

We present a protocol for generating on-demand, indistinguishable single photons on a silicon photonic integrated chip. The source is a time-multiplexed spontaneous parametric down-conversion element that allows optimization of single-photon versus multiphoton emission while realizing high output rate and indistinguishability. We minimize both the scaling of active elements and the scaling of active element loss with multiplexing. We then discuss detection strategies and data processing to further optimize the procedure. We simulate an improvement in single-photon-generation efficiency over previous time-multiplexing protocols, assuming existing fabrication capabilities. We then apply this system to generate heralded Bell states. The generation efficiency of both nonclassical states could be increased substantially with improved fabrication procedures.

Functionalized Graphene Enables Highly Efficient Solar Thermal Steam Generation.

Science.gov (United States)

Yang, Junlong; Pang, Yunsong; Huang, Weixin; Shaw, Scott K; Schiffbauer, Jarrod; Pillers, Michelle Anne; Mu, Xin; Luo, Shirui; Zhang, Teng; Huang, Yajiang; Li, Guangxian; Ptasinska, Sylwia; Lieberman, Marya; Luo, Tengfei

2017-06-27

The ability to efficiently utilize solar thermal energy to enable liquid-to-vapor phase transition has great technological implications for a wide variety of applications, such as water treatment and chemical fractionation. Here, we demonstrate that functionalizing graphene using hydrophilic groups can greatly enhance the solar thermal steam generation efficiency. Our results show that specially functionalized graphene can improve the overall solar-to-vapor efficiency from 38% to 48% at one sun conditions compared to chemically reduced graphene oxide. Our experiments show that such an improvement is a surface effect mainly attributed to the more hydrophilic feature of functionalized graphene, which influences the water meniscus profile at the vapor-liquid interface due to capillary effect. This will lead to thinner water films close to the three-phase contact line, where the water surface temperature is higher since the resistance of thinner water film is smaller, leading to more efficient evaporation. This strategy of functionalizing graphene to make it more hydrophilic can be potentially integrated with the existing macroscopic heat isolation strategies to further improve the overall solar-to-vapor conversion efficiency.

Evaluación del impacto ambiental del proceso de obtención de alcohol carburante utilizando el algoritmo de reducción de residuos

Directory of Open Access Journals (Sweden)

María Isabel Montoya R.

2006-01-01

Full Text Available En el presente trabajo se evalúa el desempeño ambiental de dos procesos para la obtención de etanol a partir de materias primas propias del país como el maíz y la caña de azúcar. Inicialmente se realizó la simulación de los procesos en el software comercial Aspen Plus. Obtenidos los balances de materia y energía de los procesos, se efectuó el análisis de impacto ambiental utilizando el algoritmo de reducción de residuos (algoritmo WAR, el cual evalúa la amigabilidad ambiental de un proceso. De los resultados obtenidos, el proceso a partir de maíz presenta un menor potencial de impacto ambiental de salida que el proceso a partir de caña de azúcar. Igualmente, la mayor generación de impacto ambiental en ambos procesos se da en la categoría de potencial de toxicidad acuática, debido principalmente a la elevada carga orgánica que involucran las vinazas producidas en este proceso.

Energy efficiency resource modeling in generation expansion planning

International Nuclear Information System (INIS)

Ghaderi, A.; Parsa Moghaddam, M.; Sheikh-El-Eslami, M.K.

2014-01-01

Energy efficiency plays an important role in mitigating energy security risks and emission problems. In this paper, energy efficiency resources are modeled as efficiency power plants (EPP) to evaluate their impacts on generation expansion planning (GEP). The supply curve of EPP is proposed using the production function of electricity consumption. A decision making framework is also presented to include EPP in GEP problem from an investor's point of view. The revenue of EPP investor is obtained from energy cost reduction of consumers and does not earn any income from electricity market. In each stage of GEP, a bi-level model for operation problem is suggested: the upper-level represents profit maximization of EPP investor and the lower-level corresponds to maximize the social welfare. To solve the bi-level problem, a fixed-point iteration algorithm is used known as diagonalization method. Energy efficiency feed-in tariff is investigated as a regulatory support scheme to encourage the investor. Results pertaining to a case study are simulated and discussed. - Highlights: • An economic model for energy efficiency programs is presented. • A framework is provided to model energy efficiency resources in GEP problem. • FIT is investigated as a regulatory support scheme to encourage the EPP investor. • The capacity expansion is delayed and reduced with considering EPP in GEP. • FIT-II can more effectively increase the energy saving compared to FIT-I

Commercially Available Activated Carbon Fiber Felt Enables Efficient Solar Steam Generation.

Science.gov (United States)

Li, Haoran; He, Yurong; Hu, Yanwei; Wang, Xinzhi

2018-03-21

Sun-driven steam generation is now possible and has the potential to help meet future energy needs. Current technologies often use solar condensers to increase solar irradiance. More recently, a technology for solar steam generation that uses heated surface water and low optical concentration is reported. In this work, a commercially available activated carbon fiber felt is used to generate steam efficiently under one sun illumination. The evaporation rate and solar conversion efficiency reach 1.22 kg m -2 h -1 and 79.4%, respectively. The local temperature of the evaporator with a floating activated carbon fiber felt reaches 48 °C. Apart from the high absorptivity (about 94%) of the material, the evaporation performance is enhanced thanks to the well-developed pores for improved water supply and steam escape and the low thermal conductivity, which enables reduced bulk water temperature increase. This study helps to find a promising material for solar steam generation using a water evaporator that can be produced economically (∼6 $/m 2 ) with long-term stability.

High efficiency fourth-harmonic generation from nanosecond fiber master oscillator power amplifier

Science.gov (United States)

Mu, Xiaodong; Steinvurzel, Paul; Rose, Todd S.; Lotshaw, William T.; Beck, Steven M.; Clemmons, James H.

2016-03-01

We demonstrate high power, deep ultraviolet (DUV) conversion to 266 nm through frequency quadrupling of a nanosecond pulse width 1064 nm fiber master oscillator power amplifier (MOPA). The MOPA system uses an Yb-doped double-clad polarization-maintaining large mode area tapered fiber as the final gain stage to generate 0.5-mJ, 10 W, 1.7- ns single mode pulses at a repetition rate of 20 kHz with measured spectral bandwidth of 10.6 GHz (40 pm), and beam qualities of Mx 2=1.07 and My 2=1.03, respectively. Using LBO and BBO crystals for the second-harmonic generation (SHG) and fourth-harmonic generation (FHG), we have achieved 375 μJ (7.5 W) and 92.5 μJ (1.85 W) at wavelengths of 532 nm and 266 nm, respectively. To the best of our knowledge these are the highest narrowband infrared, green and UV pulse energies obtained to date from a fully spliced fiber amplifier. We also demonstrate high efficiency SHG and FHG with walk-off compensated (WOC) crystal pairs and tightly focused pump beam. An SHG efficiency of 75%, FHG efficiency of 47%, and an overall efficiency of 35% from 1064 nm to 266 nm are obtained.

Efficiency-improving fossil fuel technologies for electricity generation: Data selection and trends

Energy Technology Data Exchange (ETDEWEB)

Lanzi, Elisa [Fondazione Eni Enrico Mattei (Italy); Verdolini, Elena, E-mail: elena.verdolini@feem.it [Fondazione Eni Enrico Mattei (Italy); Universita Cattolica, del Sacro Cuore di Milano (Italy); Hascic, Ivan [OECD Environment Directorate (France)

2011-11-15

This paper studies patenting dynamics in efficiency improving electricity generation technologies as an important indicator of innovation activity. We build a novel database of worldwide patent applications in efficiency-improving fossil fuel technologies for electricity generation and then analyse patenting trends over time and across countries. We find that patenting has mostly been stable over time, with a recent decreasing trend. OECD countries represent the top innovators and the top markets for technology. Some non-OECD countries, and particularly China, are also very active in terms of patenting activity in this sector. The majority of patents are first filed in OECD countries and only then in BRIC and other non-OECD countries. BRIC and other non-OECD countries apply for patents that are mostly marketed domestically, but BRIC countries represent important markets for patent duplication of OECD inventions. These results are indicative of significant technology transfer in the field of efficiency-improving technologies for electricity production. - Highlights: > We study innovation in efficiency-improving electricity generation technologies. > Relevant patents are identified and used as an indicator of innovation. > We show that there is significant technology transfer in this field. > Most patents are first filed in OECD countries and then in non-OECD countries. > Patents in non-OECD countries are mostly marketed domestically.

Very High Efficiency Reactor (VHER) Concepts for Electrical Power Generation and Hydrogen Production

International Nuclear Information System (INIS)

PARMA JR, EDWARD J.; PICKARD, PAUL S.; SUO-ANTTILA, AHTI JORMA

2003-01-01

The goal of the Very High Efficiency Reactor study was to develop and analyze concepts for the next generation of nuclear power reactors. The next generation power reactor should be cost effective compared to current power generation plant, passively safe, and proliferation-resistant. High-temperature reactor systems allow higher electrical generating efficiencies and high-temperature process heat applications, such as thermo-chemical hydrogen production. The study focused on three concepts; one using molten salt coolant with a prismatic fuel-element geometry, the other two using high-pressure helium coolant with a prismatic fuel-element geometry and a fuel-pebble element design. Peak operating temperatures, passive-safety, decay heat removal, criticality, burnup, reactivity coefficients, and material issues were analyzed to determine the technical feasibility of each concept

Efficient thermo-mechanical generation of electricity from the heat of radioisotopes

International Nuclear Information System (INIS)

Cooke-Yarborough, E.H.; Yeats, F.W.

1975-01-01

The thermomechanical generator uses a thermomechanical oscillator to convert heat efficiently into a mechanical oscillation which in turn excites a suitable transducer to generate alternating electricity. The thermomechanical oscillator used is based on the Stirling cycle, but avoids the need for rotary motion and for sliding pistons by having a mechanically-resonant, spring-suspended displacer, and by using an oscillating metal diaphragm to provide the mechanical output. The diaphragm drives an alternator consisting of a spring-suspended permanent magnet oscillating between fixed pole pieces which carry the electrical power output windings. Because a thermomechanical generator is much more efficient than a thermo-electric generator at comparable temperatures, it is particularly suitable for use with a radioisotope heat source. The amounts of radioisotope and of shielding required are both greatly reduced. A machine heated by radioisotopes and delivering 10.7W ac at 80Hz began operating in October, 1974. Operating experience with this machine is reported, and these results, together with those obtained with higher-powered machines heated by other means, are used to calculate characteristics and performance of thermo-mechanical radioisotope generators capable of using heat sources such as the waste-management 90 Sr radioisotope sources becoming available from the US nuclear waste management programme. A design to use one of these heat sources in a 52-W underwater generator is described

Assessing the power generation, pollution control, and overall efficiencies of municipal solid waste incinerators in Taiwan

Energy Technology Data Exchange (ETDEWEB)

Chang, Dong-Shang; Yang, Fu-Chiang [Department of Business Administration, National Central University, 300 Jhongda Rd., Jhongli City, Taoyuan County, 320 Taiwan (China)

2011-02-15

This paper evaluates the productivity of municipal solid waste incinerators (MSWIs) by addressing the following questions: (1) to what extent should one further increase the production of power generation while maintaining the emission of noxious air at the current level?; (2) To what extent should one further decrease the emission of noxious air while maintaining the production of power generation at the current level?; and (3) To what extent should one increase the production of power generation and decrease the emission of noxious air simultaneously? To effectively address these questions to improve performance, the power generation and pollution control efficiencies are evaluated using TODEA (two-objective data envelopment analysis), as well as the overall efficiency evaluated using Tone's NS-overall model (slacks-based measure with non-separable desirable and undesirable outputs for evaluating overall efficiency). A MSWI case study in Taiwan with the panel data covering the period of 2004-2008 reveals that the power generation and overall efficiencies of build-operate-transfer are more efficient, on average, than those of public-own-operate and build-own-operate. However, the three building and operation types do not significantly differ in pollution control efficiency. (author)

Behaviours, transmissions, generations: why is energy efficiency not enough?

Energy Technology Data Exchange (ETDEWEB)

Garabuau-Moussaoui, Isabelle (Electricite de France, Research and Development (France))

2009-07-01

Energy use is nowadays a very important question, in the context of global warming and expensive prices of energy. 'Energy conservation' is a paradox: environmental awareness increases, but also energy demand. Sociological knowledge concerning energy uses and energy savings remains important to understand the possible evolutions of practices and values and thus the possible future energy policies. Can the 'consumer society' become a 'less energy-intensive' society? This paper proposes to innovate with a 'new' way to analyse behaviours and to help policy makers to break the walls of 'the behavioural complexity'. We argue that energy efficiency, energy-using products and activities are socially embedded. More specifically, they depend on the 'social age' of people (children, teenagers, young adults, parents, old age people) and on their generation (events, experiences that people did live). The demonstration is based on the analysis of several qualitative studies carried out in France, showing that the generational and social ages analysis could be very efficient and innovative to understand: How are information, policies and energy-efficient technologies understood and embodied by people according to their age and their 'life story'? What kind of 'energy-related material culture' have people, and how does it evolve during the life? In a context of increasing energy demand, is it possible to change the energy-intensive 'socio-technical' mainstream towards a more sustainable way of life? What are the best moments during life for a behavioural change towards a less energy intensive way of life? Can we count on the new generation, to be more aware and less 'energy-intensive'?

Assessment of national waste generation in EU Member States’ efficiency

OpenAIRE

Halkos, George; Petrou, Kleoniki Natalia

2018-01-01

Waste generation and management may be considered as either a by-product of economic actions or even used as input to economic activity like energy recovery. Every country produces different amounts of municipal solid waste (MSW) and with different composition. This paper deals with the efficiency of 28 EU Member States for the years 2008, 2010 and 2012 by employing Data Envelopment Analysis (DEA) and by using eight parameters, namely waste generation, employment rate, capital formation, GDP,...

Generation of Efficient High-Level Hardware Code from Dataflow Programs

OpenAIRE

Siret , Nicolas; Wipliez , Matthieu; Nezan , Jean François; Palumbo , Francesca

2012-01-01

High-level synthesis (HLS) aims at reducing the time-to-market by providing an automated design process that interprets and compiles high-level abstraction programs into hardware. However, HLS tools still face limitations regarding the performance of the generated code, due to the difficulties of compiling input imperative languages into efficient hardware code. Moreover the hardware code generated by the HLS tools is usually target-dependant and at a low level of abstraction (i.e. gate-level...

Conformación de equipos de proyectos de software aplicando algoritmos metaheurísticos de trayectoria multiobjetivo

Directory of Open Access Journals (Sweden)

Ana Lilian Infante

2014-12-01

Full Text Available La inadecuada conformación de equipos de proyecto de software es un problema que afecta a la industria de software a nivel mundial. Este proceso resulta complejo, teniendo en cuenta que debe considerar varios factores, como son, asignar a los roles del equipo las personas con las competencias apropiadas, considerar las incompatibilidades entre los miembros y la carga de trabajo, entre otros. Esta situación se torna más compleja en organizaciones medianas y grandes, debido a la gran cantidad de combinaciones de asignaciones posibles, por lo que esta etapa es prácticamente imposible de abordar de manera eficiente, sin la ayuda de modelos matemáticos que representen el problema a resolver lo más objetivamente posible. Este trabajo toma como antecedente un modelo que incluye tanto factores individuales como factores de equipo y plantea: maximizar las competencias de los trabajadores, minimizar las incompatibilidades entre los miembros del equipo y balancear la carga de trabajo. Incluye además, en una versión ampliada del modelo, minimizar el costo de desarrollar software a distancia. El modelo citado responde a un problema de optimización combinatorio multiobjetivo, por lo que para su solución se utilizaron algunas variantes multiobjetivo de los algoritmos metaheurísticos: Búsqueda Tabú, Recocido Simulado y Escalador de Colinas. El estudio experimental realizado ha llevado a identificar que las variantes multiobjetivo del Escalador de Colinas: Escalador de Colinas Estocático Multiobjetivo, Escalador de Colinas Multiobjetivo por mayor distancia y Escalador de Colinas Multiobjetivo con Reinicio, así como el algoritmo Recocido Simulado Multiobjetivo Multicaso son los que mejores resultados obtienen en este problema.

Efficient concept for generation of diffraction-limited green light by sum-frequency generation of spectrally combined tapered diode lasers

DEFF Research Database (Denmark)

Müller, André; Jensen, Ole Bjarlin; Hasler, Karl-Heinz

2012-01-01

In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power signific......In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power...... significantly. By combining two distributed Bragg reflector tapered diode lasers we achieve a 2.5–3.2 fold increase in power and a maximum of 3.9 W of diffraction-limited green light. At this power level, green diode laser systems have a high application potential, e.g., within the biomedical field. Our concept...

Biomass gasification for electricity generation with internal combustion engines. Process efficiency

International Nuclear Information System (INIS)

Lesme-Jaén, René; Garcia Faure, Luis; Recio Recio, Angel; Oliva Ruiz, Luis; Pajarín Rodríguez, Juan; Revilla Suarez, Dennis

2015-01-01

Biomass is a renewable source of energy worldwide increased prospects for its potential and its lower environmental impact compared to fossil fuels. By processes and energy conversion technologies it is possible to obtain fuels in solid, liquid and gaseous form from any biomass. The biomass gasification is the thermal conversion thereof into a gas, which can be used for electricity production with the use of internal combustion engines with a certain level of efficiency, which depends on the characteristics of biomass and engines used. In this work the evaluation of thermal and overall efficiency of the gasification in Integrated Forestry Enterprise of Santiago de Cuba, designed to generate electricity from waste from the forest industry is presented. Is a downdraft gasifier reactor, COMBO-80 model and engine manufacturing Hindu (diesel) model Leyland modified to work with producer gas. The evaluation was carried out for different loads (electric power generated) engine from experimental measurements of flow and composition of the gas supplied to the engine. The results show that the motor operates with a thermal efficiency in the range of 20-32% with an overall efficiency between 12-25%. (full text)

Efficient charge generation by relaxed charge-transfer states at organic interfaces

KAUST Repository

Vandewal, Koen

2013-11-17

Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

Efficient charge generation by relaxed charge-transfer states at organic interfaces

KAUST Repository

Vandewal, Koen; Albrecht, Steve N.; Hoke, Eric T.; Graham, Kenneth; Widmer, Johannes; Douglas, Jessica D.; Schubert, Marcel; Mateker, William R.; Bloking, Jason T.; Burkhard, George F.; Sellinger, Alan; Frechet, Jean; Amassian, Aram; Riede, Moritz Kilian; McGehee, Michael D.; Neher, Dieter; Salleo, Alberto

2013-01-01

Interfaces between organic electron-donating (D) and electron-accepting (A) materials have the ability to generate charge carriers on illumination. Efficient organic solar cells require a high yield for this process, combined with a minimum of energy losses. Here, we investigate the role of the lowest energy emissive interfacial charge-transfer state (CT1) in the charge generation process. We measure the quantum yield and the electric field dependence of charge generation on excitation of the charge-transfer (CT) state manifold via weakly allowed, low-energy optical transitions. For a wide range of photovoltaic devices based on polymer:fullerene, small-molecule:C60 and polymer:polymer blends, our study reveals that the internal quantum efficiency (IQE) is essentially independent of whether or not D, A or CT states with an energy higher than that of CT1 are excited. The best materials systems show an IQE higher than 90% without the need for excess electronic or vibrational energy. © 2014 Macmillan Publishers Limited.

An ultra-efficient nonlinear planar integrated platform for optical signal processing and generation

DEFF Research Database (Denmark)

Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

2017-01-01

This paper will discuss the recently developed integrated platform: AlGaAs-oninsulator and its broad range of nonlinear applications. Recent demonstrations of broadband optical signal processing and efficient frequency comb generations in this platform will be reviewed.......This paper will discuss the recently developed integrated platform: AlGaAs-oninsulator and its broad range of nonlinear applications. Recent demonstrations of broadband optical signal processing and efficient frequency comb generations in this platform will be reviewed....

Adaptación del algoritmo MARACAS para segmentación de la arteria carótida y cuantificación de estenosis en imágenes TAC

Directory of Open Access Journals (Sweden)

Marcela Hernandez

2010-09-01

Full Text Available En este artículo se describen las adaptaciones hechas al algoritmo MARACAS para segmentar y cuantificar estructuras vasculares en imágenes TAC de la arteria carótida. El algoritmo MARACAS, que está basado en un modelo elástico y en un análisis de los valores y vectores propios de la matriz de inercia, fue inicialmente diseñado para segmentar una sola arteria en imágenes ARM. Las modificaciones están principalmente enfocadas a tratar las especificidades de las imágenes TAC, así como la presencia de bifurcaciones. Los algoritmos implementados en esta nueva versión se clasifican en dos niveles. 1 Los procesamientos de bajo nivel (filtrado de ruido y de artificios direccionales, presegmentación y realce destinados a mejorar la calidad de la imagen y presegmentarla. Estas técnicas están basadas en información a priori sobre el ruido, los artificios y los intervalos típicos de niveles de gris del lumen, del fondo y de las calcificaciones. 2 Los procesamientos de alto nivel para extraer la línea central de la arteria, segmentar el lumen y cuantificar la estenosis. A este nivel, se aplican conocimientos a priori sobre la forma y anatomía de las estructuras vasculares. El método fue evaluado en 31 imágenes suministradas en el concurso “Carotid Lumen Segmentation and Stenosis Grading Grand Challenge” 2009. Los resultados obtenidos en la segmentación arrojaron un coeficiente de similitud de Dice promedio de 80.4% comparado con la segmentación de referencia, y el error promedio de la cuantificación de estenosis fue 14.4%.

Reliability optimization in compound electric power systems with the aid of evolutionary algorithms; Optimizacion de la confiabilidad en sistemas electricos de potencia compuestos utilizando algoritmos evolucionarios

Energy Technology Data Exchange (ETDEWEB)

Gomez Hernandez, Jose Alberto

2001-11-15

The purpose of evaluating the reliability of Electric Power Systems is to estimate the ability of the system to carry out their function of taking the energy from the generating stations to the load points. This involves the reliability of generation sources and transmission that affect in the transfer of power through the transmission system that bears load loss and voltage sags between the generation and the consumption centers. In this thesis a hybrid methodology that optimize the reliability in systems generation -transmission using evolutionary algorithms is developed. This technique of optimization determines the optimum number of components (parallel redundancy in lines) and shunt compensation in load nodes necessary to maximize reliability, subject to cost restrictions, and considering security conditions in steady state, using the smallest singular value technique. The objective function will be defined as stochastic function, where the measure of interests is the smallest singular value of the Jacobian matrix of power flows solution of the most severe event according to the evaluation of reliability of the generation transmission system, this formulation is a combination of integer and continuous non linear programming, where the conventional mathematical programming algorithms present difficulties in robustness and global optimal search. The fault in generation units is determined by using the state sampling together with the transmission system by Monte Carlo simulation for a desired load level. For events where violations in security exist (lines loading, violation in voltage in load nodes and violation in reactive power of generation nodes) a model of active and reactive power dispatch is used in order to correct these violations by means of the exact penalty function linear programming technique to proceeded to determine the stability of voltage in steady state by means of the smallest singular value technique and the participation factors of nodes

Efficient power generating portfolio in Brazil: Conciliating cost, emissions and risk

International Nuclear Information System (INIS)

Losekann, Luciano; Marrero, Gustavo A.; Ramos-Real, Francisco J.; Fagundes de Almeida, Edmar Luiz

2013-01-01

The main purpose of this paper is to assess efficiency of the Brazilian electricity generation mix proposed in the 2020 Decennial Plan for Energy Expansion (DPEE 2020). It evaluates estimated costs, risks and CO 2 emissions following the mean–variance portfolio theory. The efficiency frontier is estimated for three CO 2 prices scenarios: no CO 2 prices, low CO 2 price and high CO 2 price. The planned portfolio in Brazil presented in the DPEE 2020 is relatively close to the efficient frontier, however there is still room for risk mitigation by diversifying the energy portfolio. As there is currently no CO 2 price in Brazil, the tendency is that diversification increases fossil fuel share in the energy mix, but the introduction of a CO 2 price can be an option to promote renewables. This type of large general market framework can contribute to reduce market uncertainties by reducing the level of government′s discretionary activism. -- Highlights: •We use portfolio theory to evaluate Brazilian generation mix expansion. •The Brazilian expansion plan is evaluated in three CO 2 price scenarios. •It is room to efficiency gains through portfolio diversification. •When CO 2 is not priced, fossil fuel increases it shares in the efficient portfolio. •High CO 2 prices increase the share of wind and biomass in the mix

OPTIMIZACIÓN DE REDES 3G UTILIZANDO ALGORITMOS CONTROL DE ADMISIÓN DE LLAMADA (CAC Y REORGANIZACIÓN DE CARGA (LDR

Directory of Open Access Journals (Sweden)

Darío Fernando Romo Cabrera

2012-08-01

Full Text Available Este artículo presenta el comportamiento de los algoritmos control de admisión de llamada CAC y reorganización de la carga LDR. Se  analizan dos escenarios donde son utilizados para mejorar el rendimiento de la red 3G. En el primero de ellos se presenta un caso de congestión de potencia en el uplink y en el segundo se analiza el nivel de congestión de elementos de canal CE en el uplink.

Efficient On-chip Optical Microresonator for Optical Comb Generation: Design and Fabrication

Science.gov (United States)

Han, Kyunghun

An optical frequency comb is a series of equally spaced frequency components. It has gained much attention since Nobel physics prize was awarded John L. Hall and Theodor W. Hansch for their contribution to the optical frequency comb technique in 2005. The optical frequency comb has been extensively studied because of its precision as a tool for spectroscopy, and is now widely used in bio- and chemical sensors, optical clocks, mode-locked dark pulse generation, soliton generation, and optical communication. Recently, thanks to the developments in nanotechnology, the optical frequency comb generation is made possible at a chip-scale level with microresonators. However, because the threshold power of the optical frequency comb generation is beyond the capability of the on-chip laser source, efficient microresonator is required. Here, we demonstrate an ultra-compact and highly efficient strip-slot direct mode coupler, aiming to achieve slotted silicon microresonator cladded with nonlinear polymer Poly-DDMEBT in SOI platform. As an application of the strip-slot direct mode coupling, a double slot fiber-to-chip edge coupler is demonstrated showing 2 dB insertion loss reduction compared to the conventional single tip edge coupler. For silicon nitride platform, we investigated evanescent wave coupling of microresonator, focusing on bus waveguide geometry optimization. The optimized waveguide width offers an efficient excitation of a fundamental mode in the resonator waveguide. This investigation can benefit low threshold comb generation by enhancing the extinction ratio. We experimentally demonstrated the high Q-factor micro-ring resonator with intrinsic Q of 12.6 million as well as the single FSR comb generation with 63 mW.

Efficiency-improving fossil fuel technologies for electricity generation: Data selection and trends

International Nuclear Information System (INIS)

Lanzi, Elisa; Verdolini, Elena; Hascic, Ivan

2011-01-01

This paper studies patenting dynamics in efficiency improving electricity generation technologies as an important indicator of innovation activity. We build a novel database of worldwide patent applications in efficiency-improving fossil fuel technologies for electricity generation and then analyse patenting trends over time and across countries. We find that patenting has mostly been stable over time, with a recent decreasing trend. OECD countries represent the top innovators and the top markets for technology. Some non-OECD countries, and particularly China, are also very active in terms of patenting activity in this sector. The majority of patents are first filed in OECD countries and only then in BRIC and other non-OECD countries. BRIC and other non-OECD countries apply for patents that are mostly marketed domestically, but BRIC countries represent important markets for patent duplication of OECD inventions. These results are indicative of significant technology transfer in the field of efficiency-improving technologies for electricity production. - Highlights: → We study innovation in efficiency-improving electricity generation technologies. → Relevant patents are identified and used as an indicator of innovation. → We show that there is significant technology transfer in this field. → Most patents are first filed in OECD countries and then in non-OECD countries. → Patents in non-OECD countries are mostly marketed domestically.

Charge Generation Dynamics in Efficient All-Polymer Solar Cells: Influence of Polymer Packing and Morphology.

Science.gov (United States)

Gautam, Bhoj R; Lee, Changyeon; Younts, Robert; Lee, Wonho; Danilov, Evgeny; Kim, Bumjoon J; Gundogdu, Kenan

2015-12-23

All-polymer solar cells exhibit rapid progress in power conversion efficiency (PCE) from 2 to 7.7% over the past few years. While this improvement is primarily attributed to efficient charge transport and balanced mobility between the carriers, not much is known about the charge generation dynamics in these systems. Here we measured exciton relaxation and charge separation dynamics using ultrafast spectroscopy in polymer/polymer blends with different molecular packing and morphology. These measurements indicate that preferential face-on configuration with intermixed nanomorphology increases the charge generation efficiency. In fact, there is a direct quantitative correlation between the free charge population in the ultrafast time scales and the external quantum efficiency, suggesting not only the transport but also charge generation is key for the design of high performance all polymer solar cells.

Efficient generation of induced pluripotent stem cells from human bone marrow mesenchymal stem cells.

Science.gov (United States)

Yulin, X; Lizhen, L; Lifei, Z; Shan, F; Ru, L; Kaimin, H; Huang, H

2012-01-01

Ectopic expression of defined sets of genetic factors can reprogramme somatic cells to induced pluripotent stem cells (iPSCs) that closely resemble embryonic stem cells. However, the low reprogramming efficiency is a significant handicap for mechanistic studies and potential clinical application. In this study, we used human bone marrow-derived mesenchymal stem cells (hBMMSCs) as target cells for reprogramming and investigated efficient iPSC generation from hBMMSCs using the compounds of p53 siRNA, valproic acid (VPA) and vitamin C (Vc) with four transcription factors OCT4, SOX2, KLF4, and c-MYC (compound induction system). The synergetic mechanism of the compounds was studied. Our results showed that the compound induction system could efficiently reprogramme hBMMSCs to iPSCs. hBMMSC-derived iPSC populations expressed pluripotent markers and had multi-potential to differentiate into three germ layer-derived cells. p53 siRNA, VPA and Vc had a synergetic effect on cell reprogramming and the combinatorial use of these substances greatly improved the efficiency of iPSC generation by suppressing the expression of p53, decreasing cell apoptosis, up-regulating the expression of the pluripotent gene OCT4 and modifying the cell cycle. Therefore, our study highlights a straightforward method for improving the speed and efficiency of iPSC generation and provides versatile tools for investigating early developmental processes such as haemopoiesis and relevant diseases. In addition, this study provides a paradigm for the combinatorial use of genetic factors and molecules to improve the efficiency of iPSC generation.

Milking technique of sup(99m)Tc generators and labeling efficiencies

International Nuclear Information System (INIS)

Salehi, N.; Guignard, P.A.

1985-01-01

Increased levels of 99 Tc in generator produced sup(99m)Tc have an adverse effect on the labelling efficiency of red blood cells and human serum albumin. A two-step milking technique in which the first 1-2 ml of eluate is discarded has been found to produce higher and more constant labelling efficiency of lymphocytes and platelets than a one-step procedure. Binding efficiency of platelet-rich plasma and lymphocytes with sup(99m)Tc is greater in the two-step technique. High activity concentration in the eluate for critical labelling is between 1.5-3 ml. (U.K.)

3D-Printed, All-in-One Evaporator for High-Efficiency Solar Steam Generation under 1 Sun Illumination.

Science.gov (United States)

Li, Yiju; Gao, Tingting; Yang, Zhi; Chen, Chaoji; Luo, Wei; Song, Jianwei; Hitz, Emily; Jia, Chao; Zhou, Yubing; Liu, Boyang; Yang, Bao; Hu, Liangbing

2017-07-01

Using solar energy to generate steam is a clean and sustainable approach to addressing the issue of water shortage. The current challenge for solar steam generation is to develop easy-to-manufacture and scalable methods which can convert solar irradiation into exploitable thermal energy with high efficiency. Although various material and structure designs have been reported, high efficiency in solar steam generation usually can be achieved only at concentrated solar illumination. For the first time, 3D printing to construct an all-in-one evaporator with a concave structure for high-efficiency solar steam generation under 1 sun illumination is used. The solar-steam-generation device has a high porosity (97.3%) and efficient broadband solar absorption (>97%). The 3D-printed porous evaporator with intrinsic low thermal conductivity enables heat localization and effectively alleviates thermal dissipation to the bulk water. As a result, the 3D-printed evaporator has a high solar steam efficiency of 85.6% under 1 sun illumination (1 kW m -2 ), which is among the best compared with other reported evaporators. The all-in-one structure design using the advanced 3D printing fabrication technique offers a new approach to solar energy harvesting for high-efficiency steam generation. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The influence of Thomson effect in the energy and exergy efficiency of an annular thermoelectric generator

International Nuclear Information System (INIS)

Kaushik, S.C.; Manikandan, S.

2015-01-01

Highlights: • Exergy analysis in the annular thermoelectric generator (ATEG) system is proposed. • Analytical expressions for the power output, exergy efficiency of an ATEG is derived. • The effects of S r , R L , and θ in P out and exergy efficiency of an ATEG is studied. • The influence of Thomson effect in P out and exergy efficiency of an ATEG is studied. - Abstract: The exoreversible thermodynamic model of an annular thermoelectric generator (ATEG) considering Thomson effect in conjunction with Peltier, Joule and Fourier heat conduction has been investigated using exergy analysis. New expressions for optimum current at the maximum power output and maximum energy, exergy efficiency conditions, and dimensionless irreversibilities in the ATEG are derived. The modified expression for figure of merit of a thermoelectric generator considering the Thomson effect has also been obtained. The results show that the power output, energy and exergy efficiency of the ATEG is lower than the flat plate thermoelectric generator. The effects of annular shape parameter (S r = r 2 /r 1 ), load resistance (R L ), dimensionless temperature ratio (θ = T h /T c ) and the thermal and electrical contact resistances in power output, energy/exergy efficiency of the ATEG have been studied. It has also been proved that because of the influence of Thomson effect, the power output and energy/exergy efficiency of the ATEG is reduced. This study will help in the designing of the actual annular thermoelectric generation systems

HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER

Energy Technology Data Exchange (ETDEWEB)

BROWN,LC; BESENBRUCH,GE; LENTSCH,RD; SCHULTZ,KR; FUNK,JF; PICKARD,PS; MARSHALL,AC; SHOWALTER,SK

2003-06-01

OAK B202 HIGH EFFICIENCY GENERATION OF HYDROGEN FUELS USING NUCLEAR POWER. Combustion of fossil fuels, used to power transportation, generate electricity, heat homes and fuel industry provides 86% of the world's energy. Drawbacks to fossil fuel utilization include limited supply, pollution, and carbon dioxide emissions. Carbon dioxide emissions, thought to be responsible for global warming, are now the subject of international treaties. Together, these drawbacks argue for the replacement of fossil fuels with a less-polluting potentially renewable primary energy such as nuclear energy. Conventional nuclear plants readily generate electric power but fossil fuels are firmly entrenched in the transportation sector. Hydrogen is an environmentally attractive transportation fuel that has the potential to displace fossil fuels. Hydrogen will be particularly advantageous when coupled with fuel cells. Fuel cells have higher efficiency than conventional battery/internal combustion engine combinations and do not produce nitrogen oxides during low-temperature operation. Contemporary hydrogen production is primarily based on fossil fuels and most specifically on natural gas. When hydrogen is produced using energy derived from fossil fuels, there is little or no environmental advantage. There is currently no large scale, cost-effective, environmentally attractive hydrogen production process available for commercialization, nor has such a process been identified. The objective of this work is to find an economically feasible process for the production of hydrogen, by nuclear means, using an advanced high-temperature nuclear reactor as the primary energy source. Hydrogen production by thermochemical water-splitting (Appendix A), a chemical process that accomplishes the decomposition of water into hydrogen and oxygen using only heat or, in the case of a hybrid thermochemical process, by a combination of heat and electrolysis, could meet these goals. Hydrogen produced from

The determinants of cost efficiency of hydroelectric generating plants: A random frontier approach

International Nuclear Information System (INIS)

Barros, Carlos P.; Peypoch, Nicolas

2007-01-01

This paper analyses the technical efficiency in the hydroelectric generating plants of a main Portuguese electricity enterprise EDP (Electricity of Portugal) between 1994 and 2004, investigating the role played by increase in competition and regulation. A random cost frontier method is adopted. A translog frontier model is used and the maximum likelihood estimation technique is employed to estimate the empirical model. We estimate the efficiency scores and decompose the exogenous variables into homogeneous and heterogeneous. It is concluded that production and capacity are heterogeneous, signifying that the hydroelectric generating plants are very distinct and therefore any energy policy should take into account this heterogeneity. It is also concluded that competition, rather than regulation, plays the key role in increasing hydroelectric plant efficiency

Algoritmo para determinação do amortecimento de materiais cerâmicos pela técnica das freqüências naturais de vibração via excitação por impulso Algorithm to determine the damping of ceramic materials by the impulse excitation technique

Directory of Open Access Journals (Sweden)

A. H. A. Pereira

2012-06-01

Full Text Available O amortecimento ou atrito interno é uma das propriedades mais sensíveis de materiais e estruturas tanto em escala macro como microscópica e um bom indicador para a caracterização de danos estruturais, sendo particularmente sensível à presença de trincas e micro-trincas. O objetivo deste trabalho foi desenvolver um algoritmo que permitisse incorporar a caracterização do amortecimento à técnica das freqüências naturais de vibração via excitação por impulso, já bem estabelecida pela norma ASTM E1876 e amplamente empregada na determinação não-destrutiva dos módulos elásticos de materiais cerâmicos. Foi desenvolvido um algoritmo para a determinação do amortecimento fundamentado na análise de sinal no domínio de tempo-freqüência, no método do decremento logarítmico e no modelo viscoelástico equivalente. O algoritmo foi validado empregando um gerador de ondas de formato arbitrário e aplicado na caracterização de dois materiais, sendo um concreto refratário de alta alumina, com e sem dano por choque térmico, e um aço SAE 1020. O algoritmo foi eficiente ao determinar a frequência e o amortecimento de sinais arbitrários e dos corpos de prova, e em limitar a análise ao modo de vibração de interesse, minimizando assim a interferência de outros modos. O algoritmo permitiu integrar com eficiência o cálculo do amortecimento à técnica de excitação por impulso.Damping is one of the most sensitive properties of materials and structures, in macro and microscopic scale, which makes it particularly sensitive to the presence of cracks and micro-cracks and a good parameter to the characterization of structural damages. The aim of this work was to develop an algorithm to allow the incorporation of the damping characterization to the natural frequencies of vibration technique (by impulse excitation, already well established for the non-destructive determination of elastic moduli by ASTM E1876 and correlated standards

Power output and efficiency of a thermoelectric generator under temperature control

International Nuclear Information System (INIS)

Chen, Wei-Hsin; Wu, Po-Hua; Wang, Xiao-Dong; Lin, Yu-Li

2016-01-01

Highlights: • Power output and efficiency of a thermoelectric generator (TEG) is studied. • Temperatures at the module’s surfaces are approximated by sinusoidal functions. • Mean output power and efficiency are enhanced by the temperature oscillation. • The maximum mean efficiency of the TEG in this study is 8.45%. • The phase angle of 180° is a feasible operation for maximizing the performance. - Abstract: Operation control is an effective way to improve the output power of thermoelectric generators (TEGs). The present study is intended to numerically investigate the power output and efficiency of a TEG and find the operating conditions for maximizing its performance. The temperature distributions at the hot side and cold side surfaces of the TEG are approximated by sinusoidal functions. The influences of the temperature amplitudes at the hot side surface and the cold side surface, the phase angle, and the figure-of-merit (ZT) on the performance of the TEG are analyzed. The predictions indicate that the mean output power and efficiency of the TEG are significantly enhanced by the temperature oscillation, whereas the mean absorbed heat by the TEG is slightly influenced. An increase in the temperature amplitude of the hot side surface and the phase angle can effectively improve the performance. For the phase angle of 0°, a smaller temperature amplitude at the cold side surface renders the better performance compared to that with a larger amplitude. When the ZT value increases from 0.736 to 1.8, the mean efficiency at the phase angle of 180° is amplified by a factor of 1.72, and the maximum mean efficiency is 8.45%. In summary, a larger temperature amplitude at the hot side surface with the phase angle of 180° is a feasible operation for maximizing the performance.

Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation.

Science.gov (United States)

Zhou, Lin; Tan, Yingling; Ji, Dengxin; Zhu, Bin; Zhang, Pei; Xu, Jun; Gan, Qiaoqiang; Yu, Zongfu; Zhu, Jia

2016-04-01

The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber-based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m(-2)). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices.

The exogenous factors affecting the cost efficiency of power generation

International Nuclear Information System (INIS)

Chang, D.-S.; Chen, Y.-T.; Chen, W.-D.

2009-01-01

This paper employs a stochastic frontier analysis (SFA) to examine cost efficiency and scale economies in Taiwan Power Company (TPC) by using the panel data covering the period of 1995-2006. In most previous studies, the efficiency estimated by the Panel Data without testing the endogeneity may bring about a biased estimator resulting from the correlation between input and individual effect. A Hausman test is conducted in this paper to examine the endogeneity of input variables and thus an appropriate model is selected based on the test result. This study finds that the power generation executes an increasing return to scale across all the power plants based on the pooled data. We also use installed capacity, service years of the power plant, and type of fuel as explanatory variable for accounting for the estimated cost efficiency of each plant by a logistic regression model to examine the factor affecting the individual efficiency estimates. The results demonstrate that the variable of installed capacity keeps a positive relationship with cost efficiency while the factor of working years has a negative relationship.

Optimización topológica mediante algoritmos genéticos, estrategias evolutivas y el método de Baluja

OpenAIRE

Estupiñan, J.; Oñate, E.; Suárez, B.

1998-01-01

El trabajo presenta la aplicación de varios mdtodos evolutivos al campo de la optimización topológica de estructuras. El trabajo desarrollado se basa en la búsqueda de una distribución de material dentro de un dominio específico y bajo unas condiciones de contorno concretas. Los algoritmos evolutivos obedecen a las leyes de superviviencia del mejor dotado de Darwiri y a su base genético molecular: mutación y recombinación del material genético. Los métodos evolutivos (ME) que se presentan ...

Energy Efficient Glass Melting - The Next Generation Melter

Energy Technology Data Exchange (ETDEWEB)

David Rue

2008-03-01

The objective of this project is to demonstrate a high intensity glass melter, based on the submerged combustion melting technology. This melter will serve as the melting and homogenization section of a segmented, lower-capital cost, energy-efficient Next Generation Glass Melting System (NGMS). After this project, the melter will be ready to move toward commercial trials for some glasses needing little refining (fiberglass, etc.). For other glasses, a second project Phase or glass industry research is anticipated to develop the fining stage of the NGMS process.

Methods and analysis of factors impact on the efficiency of the photovoltaic generation

International Nuclear Information System (INIS)

Li Tianze; Zhang Xia; Jiang Chuan; Hou Luan

2011-01-01

First of all, the thesis elaborates two important breakthroughs which happened In the field of the application of solar energy in the 1950s.The 21st century the development of solar photovoltaic power generation will have the following characteristics: the continued high growth of industrial development, the significantly reducing cost of the solar cell, the large-scale high-tech development of photovoltaic industries, the breakthroughs of the film battery technology, the rapid development of solar PV buildings integration and combined to the grids. The paper makes principles of solar cells the theoretical analysis. On the basis, we study the conversion efficiency of solar cells, find the factors impact on the efficiency of the photovoltaic generation, solve solar cell conversion efficiency of technical problems through the development of new technology, and open up new ways to improve the solar cell conversion efficiency. Finally, the paper connecting with the practice establishes policies and legislation to the use of encourage renewable energy, development strategy, basic applied research etc.

Methods and analysis of factors impact on the efficiency of the photovoltaic generation

Science.gov (United States)

Tianze, Li; Xia, Zhang; Chuan, Jiang; Luan, Hou

2011-02-01

First of all, the thesis elaborates two important breakthroughs which happened In the field of the application of solar energy in the 1950s.The 21st century the development of solar photovoltaic power generation will have the following characteristics: the continued high growth of industrial development, the significantly reducing cost of the solar cell, the large-scale high-tech development of photovoltaic industries, the breakthroughs of the film battery technology, the rapid development of solar PV buildings integration and combined to the grids. The paper makes principles of solar cells the theoretical analysis. On the basis, we study the conversion efficiency of solar cells, find the factors impact on the efficiency of the photovoltaic generation, solve solar cell conversion efficiency of technical problems through the development of new technology, and open up new ways to improve the solar cell conversion efficiency. Finally, the paper connecting with the practice establishes policies and legislation to the use of encourage renewable energy, development strategy, basic applied research etc.

Thermoelectric generator performance analysis: Influence of pin tapering on the first and second law efficiencies

International Nuclear Information System (INIS)

Yilbas, B.S.; Ali, H.

2015-01-01

Highlights: • Double tapering of thermoelectric elements improves first and second law efficiency. • Pin geometric feature maximizing device output work does not maximize thermal efficiency. • Pin geometric feature maximizing first law efficiency slight alters for maximum second law efficiency. • External resistance and operating temperature ratios influence design configuration of thermoelectric generator. - Abstract: Thermoelectric generators are the important candidates for clean energy conversion from the waste heat; however, their low efficiency limits the practical applications of the devices. Tailoring the geometric configuration of the device in line with the operating conditions can improve the device performance. Consequently; in the present study, the influence of the pin geometric configuration on the thermoelectric generator performance is investigated. The dimensionless tapering parameter is introduced and its effect on the first and second law efficiencies is examined for various operating conditions including the external load resistance and the temperature ratio. It is found that the first and second law efficiencies are significantly influenced by the pin geometry. The dimensionless tapering parameter (a), increasing tapering of the thermoelectric pins, within the range of 2 ⩽ a ⩽ 4 results in improved first and second law efficiencies. However, the dimensionless tapering parameter maximizing the first and second law efficiencies does not maximize the device output power. This behavior is associated with the external load resistance which has a considerable influence on the device output power such that increasing external load resistance lowers the device output power

Assessing the power generation, pollution control, and overall efficiencies of municipal solid waste incinerators in Taiwan

International Nuclear Information System (INIS)

Chang, Dong-Shang; Yang, Fu-Chiang

2011-01-01

This paper evaluates the productivity of municipal solid waste incinerators (MSWIs) by addressing the following questions: (1) to what extent should one further increase the production of power generation while maintaining the emission of noxious air at the current level?; (2) To what extent should one further decrease the emission of noxious air while maintaining the production of power generation at the current level?; and (3) To what extent should one increase the production of power generation and decrease the emission of noxious air simultaneously? To effectively address these questions to improve performance, the power generation and pollution control efficiencies are evaluated using TODEA (two-objective data envelopment analysis), as well as the overall efficiency evaluated using Tone's NS-overall model (slacks-based measure with non-separable desirable and undesirable outputs for evaluating overall efficiency). A MSWI case study in Taiwan with the panel data covering the period of 2004-2008 reveals that the power generation and overall efficiencies of build-operate-transfer are more efficient, on average, than those of public-own-operate and build-own-operate. However, the three building and operation types do not significantly differ in pollution control efficiency. - Research highlights: → The MSWIs implemented by private sectors are more effective than that by public sectors. → Policy makers should pay more attention to the reduction of CO during waste incineration. → Three alternatives for improving the performance of MSWIs can be made available.

Evaluation of Power Generation Efficiency of Cascade Hydropower Plants: A Case Study

Directory of Open Access Journals (Sweden)

Jiahua Wei

2013-02-01

Full Text Available Effective utilization of scarce water resources has presented a significant challenge to respond to the needs created by rapid economic growth in China. In this study, the efficiency of the joint operation of the Three Gorges and Gezhouba cascade hydropower plants in terms of power generation was evaluated on the basis of a precise simulation-optimization technique. The joint operation conditions of the Three Gorges and Gezhouba hydropower plants between 2004 and 2010 were utilized in this research in order to investigate the major factors that could affect power output of the cascade complex. The results showed that the current power output of the Three Gorges and Gezhouba cascade complex had already reached around 90% of the maximum theoretical value. Compared to other influencing factors evaluated in this study, the accuracy of hydrological forecasts and flood control levels can have significant impact on the power generating efficiency, whereas the navigation has a minor influence. This research provides a solid quantitative-based methodology to assess the operation efficiency of cascade hydropower plants, and more importantly, proposes potential methods that could improve the operation efficiency of cascade hydropower plants.

Efficient production of hot plasmas through multiple-wire implosion in transmission line generators

International Nuclear Information System (INIS)

Bloomberg, H.W.

1980-01-01

Model equations for the implosion of multiple-wire arrays mounted across the electrodes of a transmission line generator are used to obtain an expression for the energy-coupling efficiency. For a useful class of imploding loads, the efficiency is shown to depend on a single dimensionless parameter. Furthermore, the efficiency curve has a maximum, and this permits an explicit optimization of the wire load parameters in terms of the machine parameters

Efficient soft x-ray generation in short wavelength laser produced plasmas

International Nuclear Information System (INIS)

Mochizuki, T.; Yamanaka, C.

1987-01-01

Intense x-ray generation in 1.053, 0.53, 0.26 μm laser-produced plasma has been investigated in the photon energy range of 0.1 to 3keV. The x-ray spectrum is found to have several humps which move to the higher energy side as the atomic number of the target increases. This atomic dependence is explained by a semi-Moseley's law and allows us to predict a target material most suitable for generating the photons of desired energies. Conversion efficiencies of 1.5 -- 3keV x-rays are obtained also as a function of laser wavelength at the intensity of 10/sup 13/W/cm/sup 2/. The conversion efficiency of keV x rays has been enhanced by a factor of 2 -- 3 with a controlled prepulse laser. From the semi-Moseley's law we find that cryogenic targets using either Xe or Kr in a liquid or solid phase may be most useful for a number of applications because they radiate 1 -- 3 keV x rays efficiently and never deposit on the x-ray optical components and the objects to be exposed

Efficient scheme for three-photon Greenberger–Horne–Zeilinger state generation

Energy Technology Data Exchange (ETDEWEB)

Ding, Dong [College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang, 050024 (China); Department of Basic Curriculum, North China Institute of Science and Technology, Beijing, 101601 (China); Yan, Feng-Li, E-mail: flyan@hebtu.edu.cn [College of Physics Science and Information Engineering, Hebei Normal University, Shijiazhuang, 050024 (China)

2013-06-17

We propose an efficient scheme for the generation of three-photon Greenberger–Horne–Zeilinger (GHZ) state with linear optics, nonlinear optics and postselection. Several devices are designed and a two-mode quantum nondemolition detection is introduced to obtain the desired state. It is worth noting that the states which have entanglement in both polarization and spatial degrees of freedom are created in one of the designed setups. The method described in the present scheme can create a large number of three-photon GHZ states in principle. We also discuss an approach to generate the desired GHZ state in the presence of channel noise.

Efficient scheme for three-photon Greenberger–Horne–Zeilinger state generation

International Nuclear Information System (INIS)

Ding, Dong; Yan, Feng-Li

2013-01-01

We propose an efficient scheme for the generation of three-photon Greenberger–Horne–Zeilinger (GHZ) state with linear optics, nonlinear optics and postselection. Several devices are designed and a two-mode quantum nondemolition detection is introduced to obtain the desired state. It is worth noting that the states which have entanglement in both polarization and spatial degrees of freedom are created in one of the designed setups. The method described in the present scheme can create a large number of three-photon GHZ states in principle. We also discuss an approach to generate the desired GHZ state in the presence of channel noise.

Joint environmental and cost efficiency analysis of electricity generation

International Nuclear Information System (INIS)

Welch, Eric; Barnum, Darold

2009-01-01

Fossil-fuel based electricity generation produces the largest proportion of human-related carbon pollution in the United States. Hence, fuel choices by steam plants are key determinants of the industry's impact on national and global greenhouse gas emissions, and key foci for climate change policy. Yet, little research has been done to examine the economic and environmental tradeoffs among the different types of fuels that are used by these plants. This paper applies a Data Envelopment Analysis procedure that incorporates the materials balance principle to estimate the allocations of coal, gas and oil inputs that minimize carbon emissions and costs. Using EIA 906 and FERC 423 data, the paper estimates cost/carbon tradeoffs facing two sets of plants: those that use coal and gas inputs, and those that use coal, gas and oil inputs. Findings for our three-input sample show that there would be a 79% increase in cost for moving from the cost-efficient point to the carbon efficient point, while there would be a 38% increase in carbon for moving from the carbon efficient point to the cost-efficient point. These conclusions indicate that, in general, the gap between efficient cost and efficient environmental production is wide, and would require substantial policy intervention, technological change or market adjustment before it could be narrowed. However, our examination of individual plants shows that what is true in general is often not true for specific plants. Some plants that are currently less efficient than those on the production frontier could produce the same amount of electricity with less carbon output and less fuel input. Additionally, many plants on the production frontier could improve both cost and carbon efficiency by changing their mixture of fossil-fuel inputs. (author)

The Efficiency Improvement by Combining HHO Gas, Coal and Oil in Boiler for Electricity Generation

Directory of Open Access Journals (Sweden)

Chia-Nan Wang

2017-02-01

Full Text Available Electricity is an essential energy that can benefit our daily lives. There are many sources available for electricity generation, such as coal, natural gas and nuclear. Among these sources, coal has been widely used in thermal power plants that account for about 41% of the worldwide electricity supply. However, these thermal power plants are also found to be a big pollution source to our environment. There is a need to explore alternative electricity sources and improve the efficiency of electricity generation. This research focuses on improving the efficiency of electricity generation through the use of hydrogen and oxygen mixture (HHO gas. In this research, experiments have been conducted to investigate the combined effects of HHO gas with other fuels, including coal and oil. The results show that the combinations of HHO with coal and oil can improve the efficiency of electricity generation while reducing the pollution to our environment.

Characterization of sliders for efficient force generation of electrostatically controlled linear actuator

International Nuclear Information System (INIS)

Nguyen, T A; Konishi, S

2014-01-01

In this paper, the characterization of sliders for efficient force generation of an electrostatically controlled linear actuator (ECLIA) is investigated. The ECLIA consists of a piezoactuator (PZT), driving and holding electrodes, multiple sliders and a guide structure. The stepping motion of the sliders is driven by the PZT actuator via an electrostatic clutch mechanism. Thus, multiple sliders can achieve parallel, independent, precise motion, and a large stroke. Previous studies have indicated that the Si bulk slider and Si electrode created an air gap owing to the deformation of the Si electrode. Thus, the Si slider generated a low pushing force. In this study, we propose a fishbone structure mounted on a flexible slider to enhance the pushing force of the slider. The flexible slider, that can deform and fit into the Si electrode to reduce the air gap, results in highly efficient electrostatic-force generation. The fishbone structure improves the longitudinal stiffness of the flexible slider for high pushing-force generation. The results show that the pushing force created by the fishbone slider was three times greater than that of the conventional Si slider. The fishbone and flexible sliders exhibited a high performance for the ECLIA. (paper)

Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

Science.gov (United States)

Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

2018-02-01

We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

Vectorización de algoritmos generales de convergencia fuerte para la solución de ecuaciones diferenciales estocásticas (SDE)

OpenAIRE

Quiñones Botero, Carlos Eduardo

2007-01-01

La teoría de las Ecuaciones Diferenciales Estocásticas (SDE) ha sido desarrollada en el último medio siglo, pero no se ha creado una librería para la solución numérica de este tipo de ecuaciones. A pesar de que actualmente existen métodos numéricos de alta eficiencia para la solución de las SDE y de que existen aplicaciones académicas e industriales en donde se utilizan, no se ha desarrollado una librería de fuente abierta que implemente vectorizadamente los mejores algoritmos disponibles act...

High efficiency focus neutron generator

Science.gov (United States)

Sadeghi, H.; Amrollahi, R.; Zare, M.; Fazelpour, S.

2017-12-01

In the present paper, the new idea to increase the neutron yield of plasma focus devices is investigated and the results are presented. Based on many studies, more than 90% of neutrons in plasma focus devices were produced by beam target interactions and only 10% of them were due to thermonuclear reactions. While propounding the new idea, the number of collisions between deuteron ions and deuterium gas atoms were increased remarkably well. The COMSOL Multiphysics 5.2 was used to study the given idea in the known 28 plasma focus devices. In this circumstance, the neutron yield of this system was also obtained and reported. Finally, it was found that in the ENEA device with 1 Hz working frequency, 1.1 × 109 and 1.1 × 1011 neutrons per second were produced by D-D and D-T reactions, respectively. In addition, in the NX2 device with 16 Hz working frequency, 1.34 × 1010 and 1.34 × 1012 neutrons per second were produced by D-D and D-T reactions, respectively. The results show that with regards to the sizes and energy of these devices, they can be used as the efficient neutron generators.

High-efficiency and flexible generation of vector vortex optical fields by a reflective phase-only spatial light modulator.

Science.gov (United States)

Cai, Meng-Qiang; Wang, Zhou-Xiang; Liang, Juan; Wang, Yan-Kun; Gao, Xu-Zhen; Li, Yongnan; Tu, Chenghou; Wang, Hui-Tian

2017-08-01

The scheme for generating vector optical fields should have not only high efficiency but also flexibility for satisfying the requirements of various applications. However, in general, high efficiency and flexibility are not compatible. Here we present and experimentally demonstrate a solution to directly, flexibly, and efficiently generate vector vortex optical fields (VVOFs) with a reflective phase-only liquid crystal spatial light modulator (LC-SLM) based on optical birefringence of liquid crystal molecules. To generate the VVOFs, this approach needs in principle only a half-wave plate, an LC-SLM, and a quarter-wave plate. This approach has some advantages, including a simple experimental setup, good flexibility, and high efficiency, making the approach very promising in some applications when higher power is need. This approach has a generation efficiency of 44.0%, which is much higher than the 1.1% of the common path interferometric approach.

PLANEAMIENTO MULTIOBJETIVO DE SISTEMAS DE DISTRIBUCIÓN USANDO UN ALGORITMO EVOLUTIVO NSGA-II PLANEJAMENTO MULTIOBJETIVO DE SISTEMAS DE DISTRIBUIÇÃO USANDO UM ALGORITMO EVOLUTIVO NSGA-II MULTIOBJECTIVE DISTRIBUTION SYSTEM PLANNING USING AN NSGA-II EVOLUTIONARY ALGORITHM

Directory of Open Access Journals (Sweden)

Libardo López

2011-06-01

Full Text Available En este artículo se presenta una metodología para solucionar el problema del planeamiento de sistemas de distribución empleando una técnica de optimización multiobjetivo. En el modelo propuesto se consideran la ubicación y dimensionamiento de nuevos elementos y la repotenciación de elementos existentes. En el planteamiento del problema se incluyen en la función objetivo los costos de inversión y de operación y la confiabilidad de la red. Este tema de investigación es de relevancia para las empresas distribuidoras de energía eléctrica, ya que permite contar con nuevas herramientas que acercan el problema a situaciones reales, tales como considerar varios objetivos, lo cual incide favorablemente en las finanzas y en la operación del sistema. En la solución del modelo se emplea un algoritmo elitista de ordenamiento no dominado (NSGA-II, y para verificar su eficiencia se recurre a un caso de la literatura especializada, que corresponde a una red de distribución de un sistema eléctrico.Neste artigo apresenta-se uma metodologia para solucionar o problema do planejamento de sistemas de distribuição empregando uma técnica de otimização multiobjetivo. No modelo proposto considera-se a localização e dimensionamento de novos elementos e a repotenciação de elementos existentes. Na abordagem do problema incluem-se na função objetivo os custos de investimento e de operação e a confiabilidade da rede. Este tema de pesquisa é de relevância para as empresas distribuidoras de energia elétrica, já que permite contar com novas ferramentas que acercam o problema a situações reais, tais como considerar vários objetivos, o qual incide favoravelmente nas finanças e na operação do sistema. Na solução do modelo emprega-se um algoritmo elitista de ordenamento não-dominado (NSGA-II, e para verificar sua eficiência se emprega um caso da literatura especializada, que corresponde a uma rede de distribuição de um sistema el

Using natural gas generation to improve power system efficiency in China

International Nuclear Information System (INIS)

Hu, Junfeng; Kwok, Gabe; Xuan, Wang; Williams, James H.; Kahrl, Fredrich

2013-01-01

China's electricity sector faces the challenge of managing cost increases, improving reliability, and reducing its environmental footprint even as operating conditions become more complex due to increasing renewable penetration, growing peak demand, and falling system load factors. Addressing these challenges will require changes in how power generation is planned, priced, and dispatched in China. This is especially true for natural gas generation, which is likely to play an important role in power systems worldwide as a flexible generation resource. Although natural gas is commonly perceived to be economically uncompetitive with coal in China, these perceptions are based on analysis that fails to account for the different roles that natural gas generation plays in power systems—baseload, load following, and peaking generation. Our analysis shows that natural gas generation is already cost-effective for meeting peak demand in China, resulting in improved capacity factors and heat rates for coal-fired generators and lower system costs. We find that the largest barrier to using natural gas for peaking generation in China is generation pricing, which could be addressed through modest reforms to support low capacity factor generation. - Highlights: • Using gas generation as a “capacity resource” in China could have multiple benefits. • Benefits include lower total costs, improved efficiency for coal generators. • Price reforms needed to support low capacity factor generation in China

Thermoelectric generators for efficiency improvement of power generation by motor generators – Environmental and economic perspectives

International Nuclear Information System (INIS)

Patyk, Andreas

2013-01-01

Highlights: ► TEGs can save costs and reduce environmental burden in a wide range of conditions. ► Reduction of the environmental burden is still possible under worse conditions. ► Under the same conditions steam expanders produce bigger amounts of electricity. ► Steam expanders are more eco-efficient in the upper performance range. ► TEG production plays only a small role for the overall assessment. -- Abstract: The use of waste heat from exhaust gas of internal combustion engines in power plants and CHP plants is considered a promising application field for thermoelectrics (TE). Some recent studies have provided important knowledge on the energy efficiency of current and future thermoelectric generators (TEGs). The focus of these studies has been primarily on the precise modelling of power units and their operation, i.e., the quantification of power production by TEGs. One of the studies additionally assessed the costs and the CO 2 emissions of fuel combustion, without equipment and fuel supply. Until now, there was no life cycle-related analysis considering TEG and power unit manufacture, environmental impacts beyond climate change and competing technologies for waste heat utilisation. In order to fill this gap, the present study applies the life cycle approach, takes account of a variety of environmental impacts and costs and compares TEGs with the competing steam expander technology. The results show that, under many conditions, TEGs in power units can save energy costs and reduce the environmental burden, i.e., they are eco-efficient. With additional expenditure, energy savings and environmental benefits can be achieved even under disadvantageous conditions. However, in the upper power range the performance of steam expanders in terms of electricity production and eco-efficiency is better. The reduction costs of greenhouse gas emissions and environmental impacts as eco-efficiency indicators show identical patterns. Under reasonable operating

Electromechanical conversion efficiency for dielectric elastomer generator in different energy harvesting cycles

Science.gov (United States)

Cao, Jian-Bo; E, Shi-Ju; Guo, Zhuang; Gao, Zhao; Luo, Han-Pin

2017-11-01

In order to improve electromechanical conversion efficiency for dielectric elastomer generators (DEG), on the base of studying DEG energy harvesting cycles of constant voltage, constant charge and constant electric field intensity, a new combined cycle mode and optimization theory in terms of the generating mechanism and electromechanical coupling process have been built. By controlling the switching point to achieve the best energy conversion cycle, the energy loss in the energy conversion process is reduced. DEG generating test bench which was used to carry out comparative experiments has been established. Experimental results show that the collected energy in constant voltage cycle, constant charge cycle and constant electric field intensity energy harvesting cycle decreases in turn. Due to the factors such as internal resistance losses, electrical losses and so on, actual energy values are less than the theoretical values. The electric energy conversion efficiency by combining constant electric field intensity cycle with constant charge cycle is larger than that of constant electric field intensity cycle. The relevant conclusions provide a basis for the further applications of DEG.

Simple and efficient generation of gap solitons in Bose-Einstein condensates

International Nuclear Information System (INIS)

Matuszewski, Michal; Krolikowski, Wieslaw; Trippenbach, Marek; Kivshar, Yuri S.

2006-01-01

We suggest an efficient method for generating matter-wave gap solitons in a repulsive Bose-Einstein condensate, when the gap soliton is formed from a condensate cloud in a harmonic trap after turning on a one-dimensional optical lattice. We demonstrate numerically that this approach does not require preparing the initial atomic wave packet in a specific state corresponding to the edge of the Brillouin zone of the spectrum, and losses that occur during the soliton generation process can be suppressed by an appropriate adiabatic switching of the optical lattice

Highly nonlinear organic crystal OHQ-T for efficient ultra-broadband terahertz wave generation beyond 10 THz.

Science.gov (United States)

Kang, Bong Joo; Baek, In Hyung; Lee, Seung-Heon; Kim, Won Tae; Lee, Seung-Jun; Jeong, Young Uk; Kwon, O-Pil; Rotermund, Fabian

2016-05-16

We report on efficient generation of ultra-broadband terahertz (THz) waves via optical rectification in a novel nonlinear organic crystal with acentric core structure, i.e. 2-(4-hydroxystyryl)-1-methylquinolinium 4-methylbenzenesulfonate (OHQ-T), which possesses an ideal molecular structure leading to a maximized nonlinear optical response for near-infrared-pumped THz wave generation. By systematic studies on wavelength-dependent phase-matching conditions in OHQ-T crystals of different thicknesses we are able to generate coherent THz waves with a high peak-to-peak electric field amplitude of up to 650 kV/cm and an upper cut-off frequency beyond 10 THz. High optical-to-THz conversion efficiency of 0.31% is achieved by efficient index matching with a selective pumping at 1300 nm.

Otimização da largura de banda de ganho de um amplificador Raman na banda "O" baseada em algoritmo genético

OpenAIRE

David Steinberg

2011-01-01

Neste trabalho a otimização da largura de banda de ganho de um amplificador Raman discreto na banda "O" utilizando algoritmo genético de um simulador comercial foi realizada. O objetivo principal do trabalho foi otimizar a maior largura de banda de ganho do amplificador Raman obtendo valores de variação de ganho menores que 0.5 dB. Utilizando uma fibra DCF (Dispersion Compensating Fiber) como meio de ganho do amplificador Raman, o número de bombeio foi variado e a variação de ganho para ca...

A 3D Photothermal Structure toward Improved Energy Efficiency in Solar Steam Generation

KAUST Repository

Shi, Yusuf

2018-04-18

Summary The energy efficiency in solar steam generation by 2D photothermal materials has approached its limit. In this work, we fabricated 3D cylindrical cup-shaped structures of mixed metal oxide as solar evaporator, and the 3D structure led to a high energy efficiency close to 100% under one-sun illumination due to the capability of the cup wall to recover the diffuse reflectance and thermal radiation heat loss from the 2D cup bottom. Additional heat was gained from the ambient air when the 3D structure was exposed under one-sun illumination, leading to an extremely high steam generation rate of 2.04 kg m−2 h−1. The 3D structure has a high thermal stability and shows great promise in practical applications including domestic wastewater volume reduction and seawater desalination. The results of this work inspire further research efforts to use 3D photothermal structures to break through the energy efficiency limit of 2D photothermal materials.

Aplicación de algoritmos genéticos a la identificación de la estructura de enlaces en portales web

Directory of Open Access Journals (Sweden)

Martínez-Torres, María del Rocío

2011-06-01

Full Text Available This paper explores website link structure, whereby websites are considered as interconnected graphs and their features are analyzed as a social network. For each root domain, two different networks are extracted: the first being the domain network and the second, the page network. In each case, a series of indicators taken from social network analysis is evaluated in order to characterize the website structure. Factor analysis may provide an appropriate statistical methodology for extracting in graphic form the principal profile of the website in terms of its internal structure. However, the large number of indicators generated by such an exploratory search would lead to a prohibitive number of possibilities. Therefore, this work proposes the use of genetic algorithms. By using this guided search over a given space of possible solutions, genetic algorithms can provide a subset of indicators able to optimize a fitness function. The results categorize corporate websites in terms of their link structure and highlight the possibilities for using genetic algorithms as a tool for knowledge discovery.

Este trabajo explora la estructura de enlaces de los portales web considerándolos como grafos interconectados y analizando sus características como una red social. A partir de cada dominio raíz se extraerán dos redes: la primera, una red de dominios y la segunda, una red de páginas accesibles desde el dominio raíz. Sobre ambas redes se evaluarán una serie de parámetros desde la perspectiva del análisis de redes sociales para caracterizar la estructura del portal. El análisis factorial proporciona la metodología estadística adecuada para extraer los principales perfiles de portales web a partir de sus características como grafo. No obstante, y debido al gran número de indicadores que se pueden obtener, la búsqueda exploratoria de los factores latentes implicaría contemplar un número de posibilidades extremadamente elevado que

Pronóstico puntos críticos de la serie temporal "consumo de energía eléctrica del sector industrial en la ciudad de Medellín,", usando algoritmos genéticos

Directory of Open Access Journals (Sweden)

Héctor Tabares

2007-01-01

Full Text Available Los algoritmos genéticos (AG están inspirados en el principio darwiniano de la evolución de las especies y en la genética. Son algoritmos probabilísticos que ofrecen un mecanismo de búsqueda paralela y adaptativa, basado en el principio de supervivencia de los más aptos y en la reproducción.Este artículo presenta una introducción a los fundamentos de los AG. También enseña el simulador software AG_UdeA desarrollado con un propósito didáctico para la enseñanza de los AG. El principal aporte consiste en la aplicación de los AG para pronosticar los puntos críticos de consumo de energía eléctrica del sector industrial de la ciudad de Medellín para un período de 24 horas.

Economic incentives for evidence generation: promoting an efficient path to personalized medicine.

Science.gov (United States)

Towse, Adrian; Garrison, Louis P

2013-01-01

The preceding articles in this volume have identified and discussed a wide range of methodological and practical issues in the development of personalized medicine. This concluding article uses the resulting insights to identify implications for the economic incentives for evidence generation. It argues that promoting an efficient path to personalized medicine is going to require appropriate incentives for evidence generation including: 1) a greater willingness on the part of payers to accept prices that reflect value; 2) consideration of some form of intellectual property protection (e.g., data exclusivity) for diagnostics to incentivize generation of evidence of clinical utility; 3) realistic expectations around the standards for evidence; and 4) public investment in evidence collection to complement the efforts of payers and manufacturers. It concludes that such incentives could build and maintain a balance among: 1) realistic thresholds for evidence and the need for payers to have confidence in the clinical utility of the drugs and tests they use; 2) payment for value, with prices that ensure cost-effectiveness for health systems; and 3) levels of intellectual property protection for evidence generation that provide a return for those financing research and development, while encouraging competition to produce both better and more efficient tests. Copyright © 2013, International Society for Pharmacoeconomics and Outcomes Research (ISPOR). Published by Elsevier Inc.

Effect of turbine materials on power generation efficiency from free water vortex hydro power plant

International Nuclear Information System (INIS)

Sritram, P; Treedet, W; Suntivarakorn, R

2015-01-01

The objective of this research was to study the effect of turbine materials on power generation efficiency from the water free vortex hydro power plant made of steel and aluminium. These turbines consisted of five blades and were twisted with angles along the height of water. These blades were the maximum width of 45 cm. and height of 32 cm. These turbines were made and experimented for the water free vortex hydro power plant in the laboratory with the water flow rate of 0.68, 1.33, 1.61, 2.31, 2.96 and 3.63 m 3 /min and an electrical load of 20, 40, 60, 80 and 100 W respectively. The experimental results were calculated to find out the torque, electric power, and electricity production efficiency. From the experiment, the results showed that the maximum power generation efficiency of steel and aluminium turbine were 33.56% and 34.79% respectively. From the result at the maximum water flow rate of 3.63 m 3 /min, it was found that the torque value and electricity production efficiency of aluminium turbine was higher than that of steel turbine at the average of 8.4% and 8.14%, respectively. This result showed that light weight of water turbine can increase the torque and power generation efficiency. (paper)

Enhanced Efficiency of Thermoelectric Generator by Optimizing Mechanical and Electrical Structures

Directory of Open Access Journals (Sweden)

Jinlong Chen

2017-09-01

Full Text Available Much attention has been paid to the application of low temperature thermal resources, especially for power generation in recent years. Most of the current commercialized thermal (including geothermal power-generation technologies convert thermal energy to electric energy indirectly, that is, making mechanical work before producing electricity. Technology using a thermoelectric generator (TEG, however, can directly transform thermal energy into electricity through the Seebeck effect. TEG technology has many advantages such as compactness, quietness, and reliability because there are no moving parts. One of the biggest disadvantages of TEGs is the low efficiency from thermal to electric energy. For this reason, we redesigned and modified our previous 1 KW (at a temperature difference of around 120 °C TEG system. The output power of the system was improved significantly, about 34.6% greater; the instantaneous efficiency of the TEG system could reach about 6.5%. Laboratory experiments have been conducted to measure the output power at different conditions: different connection modes between TEG modules, different mechanical structures, and different temperature differences between hot and cold sides. The TEG apparatus has been tested and the data have been presented. This kind of TEG power system can be applied in many thermal and geothermal sites with low temperature resources, including oil fields where fossil and geothermal energies are coproduced.

Efficient Data Generation and Publication as a Test Tool

Science.gov (United States)

Einstein, Craig Jakob

2017-01-01

A tool to facilitate the generation and publication of test data was created to test the individual components of a command and control system designed to launch spacecraft. Specifically, this tool was built to ensure messages are properly passed between system components. The tool can also be used to test whether the appropriate groups have access (read/write privileges) to the correct messages. The messages passed between system components take the form of unique identifiers with associated values. These identifiers are alphanumeric strings that identify the type of message and the additional parameters that are contained within the message. The values that are passed with the message depend on the identifier. The data generation tool allows for the efficient creation and publication of these messages. A configuration file can be used to set the parameters of the tool and also specify which messages to pass.

Terahertz radiation generation by lasers with remarkable efficiency in electron–positron plasma

International Nuclear Information System (INIS)

Malik, Hitendra K.

2015-01-01

Photo-mixing of spatial-super-Gaussian lasers and electron–positron plasma are proposed for realizing a large amplitude nonlinear current in order to generate an efficient terahertz radiation. An external magnetic field together with a proper index of the lasers helps achieving controllable current and hence, the focused radiation of tunable frequency and power along with a remarkable efficiency of the scheme as ∼6%. - Highlights: • First proposal of photo-mixing of spatial-super-Gaussian (SSG) lasers in electron–positron (e–p) plasma. • Large amplitude nonlinear current due to the contribution of both the plasma species. • Magnetic field as an additional parameter for tunable THz radiation with a remarkable efficiency of ∼6%.

Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater.

Science.gov (United States)

Hsu, Guoo-Shyng Wang; Hsia, Chih-Wei; Hsu, Shun-Yao

2015-12-01

Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP) of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1 st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing. Copyright © 2015. Published by Elsevier B.V.

Effects of electrode settings on chlorine generation efficiency of electrolyzing seawater

Directory of Open Access Journals (Sweden)

Guoo-Shyng Wang Hsu

2015-12-01

Full Text Available Electrolyzed water has significant disinfection effects, can comply with food safety regulations, and is environmental friendly. We investigated the effects of immersion depth of electrodes, stirring, electrode size, and electrode gap on the properties and chlorine generation efficiency of electrolyzing seawater and its storage stability. Results indicated that temperature and oxidation-reduction potential (ORP of the seawater increased gradually, whereas electrical conductivity decreased steadily in electrolysis. During the electrolysis process, pH values and electric currents also decreased slightly within small ranges. Additional stirring or immersing the electrodes deep under the seawater significantly increased current density without affecting its electric efficiency and current efficiency. Decreasing electrode size or increasing electrode gap decreased chlorine production and electric current of the process without affecting its electric efficiency and current efficiency. Less than 35% of chlorine in the electrolyzed seawater was lost in a 3-week storage period. The decrement trend leveled off after the 1st week of storage. The electrolyzing system is a convenient and economical method for producing high-chlorine seawater, which will have high potential applications in agriculture, aquaculture, or food processing.

Increasing coal-fired power generation efficiency to reduce electric cost and environmental emissions

International Nuclear Information System (INIS)

Torrens, I.M.; Stenzel, W.C.

1997-01-01

New generating capacity required globally between 1993 and 2010 is estimated to be around 1500 GW, of which some two-thirds will be outside the OECD, and some 40 % in the Asian non-OECD countries. Coal is likely to account for a substantial fraction of this new generation. Today's state-of-the-art supercritical coal-fired power plant has a conversion efficiency of some 42-45 %. The capital cost increase associated with the supercritical or ultra-supercritical pulverized coal power plant compared to a conventional subcritical plant is small to negligible. The increased efficiency associated with the supercritical plant leads to an actual reduction in the total cost of electricity generated in cents/kWh, relative to a conventional plant. Despite this, the power sector continues to build subcritical plants and has no near term plans to increase the efficiency of power plants in the projects it is developing. Advanced clean coal technologies such as integrated gasification combined cycle and pressurized fluidized bed combustion will be selected for independent power projects only in very specific circumstances. Advanced clean coal plants can be operated reliably and with superior performance, and specifically that their present estimated capital costs can be reduced substantially to a point where they are competitive with state-of-the-art pulverized coal technologies. (R.P.)

Efficient temporal compression of coherent nanosecond pulses in compact SBS generator-amplifier setup

OpenAIRE

Schiemann, S.; Ubachs, W.M.G.; Hogervorst, W.

1997-01-01

A pulse compressor based on stimulated Brillouin scattering (SBS) in liquids is experimentally and theoretically investigated. It allows for the compression of Fourier-transform limited nanosecond pulses of several hundreds of millijoules of energy with both high conversion efficiency and a high temporal compression factor. The two-cell generator-amplifier arrangement is of a compact design not requiring external attenuation of the generator cell input energy. Pulses from an injection-seeded,...

An Efficient Metric of Automatic Weight Generation for Properties in Instance Matching Technique

OpenAIRE

Seddiqui, Md. Hanif; Nath, Rudra Pratap Deb; Aono, Masaki

2015-01-01

The proliferation of heterogeneous data sources of semantic knowledge base intensifies the need of an automatic instance matching technique. However, the efficiency of instance matching is often influenced by the weight of a property associated to instances. Automatic weight generation is a non-trivial, however an important task in instance matching technique. Therefore, identifying an appropriate metric for generating weight for a property automatically is nevertheless a formidab...

Estudo comparativo entre dois algoritmos de identificação de estrelas para um sensor de estrelas autônomo de campo largo.

OpenAIRE

Márcio Afonso Arimura Fialho

2007-01-01

Neste trabalho é feito um estudo comparativo entre dois algoritmos de identificação de estrelas desenvolvidos para um sensor de estrelas autônomo de campo largo em projeto no INPE - Instituto Nacional de Pesquisas Espaciais. A comparação é realizada com base nas especificações técnicas deste sensor de estrelas, cujas principais características são: campo de visada quadrado de 25,5 x 25,5 , matriz fotodetectora de 1024 1024 pixels de tecnologia CMOS-APS e precisão na determinação de atitude...

Aplicación de Algoritmos de Visión Artificial para el Control de Robots Cooperativos Móviles Dentro De Espacios Semi Estructurados

OpenAIRE

Pérez Checa, Aníbal Roberto

2016-01-01

Este trabajo presenta la aplicación de algoritmos de visión artificial para el control de dos agentes robóticos que mediante su operación en forma cooperativa desplazan al objeto dentro del espacio semi estructurado desde un punto de partida hasta un punto de llegada. El sistema funciona en base de una cámara cenital que captura la imagen que es transmitida a un computador personal el mismo que está provisto de Matlab R2013a, en el cual se procesa la información y determina las acciones de co...

Effects of water-emulsified fuel on a diesel engine generator's thermal efficiency and exhaust.

Science.gov (United States)

Syu, Jin-Yuan; Chang, Yuan-Yi; Tseng, Chao-Heng; Yan, Yeou-Lih; Chang, Yu-Min; Chen, Chih-Chieh; Lin, Wen-Yinn

2014-08-01

Water-emulsified diesel has proven itself as a technically sufficient improvement fuel to improve diesel engine fuel combustion emissions and engine performance. However, it has seldom been used in light-duty diesel engines. Therefore, this paper focuses on an investigation into the thermal efficiency and pollution emission analysis of a light-duty diesel engine generator fueled with different water content emulsified diesel fuels (WD, including WD-0, WD-5, WD-10, and WD-15). In this study, nitric oxide, carbon monoxide, hydrocarbons, and carbon dioxide were analyzed by a vehicle emission gas analyzer and the particle size and number concentration were measured by an electrical low-pressure impactor. In addition, engine loading and fuel consumption were also measured to calculate the thermal efficiency. Measurement results suggested that water-emulsified diesel was useful to improve the thermal efficiency and the exhaust emission of a diesel engine. Obviously, the thermal efficiency was increased about 1.2 to 19.9%. In addition, water-emulsified diesel leads to a significant reduction of nitric oxide emission (less by about 18.3 to 45.4%). However the particle number concentration emission might be increased if the loading of the generator becomes lower than or equal to 1800 W. In addition, exhaust particle size distributions were shifted toward larger particles at high loading. The consequence of this research proposed that the water-emulsified diesel was useful to improve the engine performance and some of exhaust emissions, especially the NO emission reduction. Implications: The accumulated test results provide a good basis to resolve the corresponding pollutants emitted from a light-duty diesel engine generator. By measuring and analyzing transforms of exhaust pollutant from this engine generator, the effects of water-emulsified diesel fuel and loading on emission characteristics might be more clear. Understanding reduction of pollutant emissions during the use

Efficient algorithm for generating spectra using line-by-line methods

International Nuclear Information System (INIS)

Sonnad, V.; Iglesias, C.A.

2011-01-01

A method is presented for efficient generation of spectra using line-by-line approaches. The only approximation is replacing the line shape function with an interpolation procedure, which makes the method independent of the line profile functional form. The resulting computational savings for large number of lines is proportional to the number of frequency points in the spectral range. Therefore, for large-scale problems the method can provide speedups of two orders of magnitude or more. A method was presented to generate line-by-line spectra efficiently. The first step was to replace the explicit calculation of the profile by the Newton divided-differences interpolating polynomial. The second step is to accumulate the lines effectively reducing their number to the number of frequency points. The final step is recognizing the resulting expression as a convolution and amenable to FFT methods. The reduction in computational effort for a configuration-to-configuration transition array with large number of lines is proportional to the number of frequency points. The method involves no approximations except for replacing the explicit profile evaluation by interpolation. Specifically, the line accumulation and convolution are exact given the interpolation procedure. Furthermore, the interpolation makes the method independent of the line profile functional form contrary to other schemes using FFT methods to generate line-by-line spectra but relying on the analytic form of the profile Fourier transform. Finally, the method relies on a uniform frequency mesh. For non-uniform frequency meshes, however, the method can be applied by using a suitable temporary uniform mesh and the results interpolated onto the final mesh with little additional cost.

Variabilidade local e regional da evapotranspiração estimada pelo algoritmo SEBAL Local and regional variability of evapotranspiration estimated by SEBAL algorithm

Directory of Open Access Journals (Sweden)

Luis C. J. Moreira

2010-12-01

Full Text Available Em face da importância em conhecer a evapotranspiração (ET para uso racional da água na irrigação no contexto atual de escassez desse recurso, algoritmos de estimativa da ET a nível regional foram desenvolvidos utilizando-se de ferramentas de sensoriamento remoto. Este estudo objetivou aplicar o algoritmo SEBAL (Surface Energy Balance Algorithms for Land em três imagens do satélite Landsat 5, do segundo semestre de 2006. As imagens correspondem a áreas irrigadas, floresta nativa densa e a Caatinga do Estado do Ceará (Baixo Acaraú, Chapada do Apodi e Chapada do Araripe. Este algoritmo calcula a evapotranspiração horária a partir do fluxo de calor latente, estimado como resíduo do balanço de energia na superfície. Os valores de ET obtidos nas três regiões foram superiores a 0,60 mm h-1 nas áreas irrigadas ou de vegetação nativa densa. As áreas de vegetação nativa menos densa apresentaram taxa da ET horária de 0,35 a 0,60 mm h-1, e valores quase nulos em áreas degradadas. A análise das médias de evapotranspiração horária pelo teste de Tukey a 5% de probabilidade permitiu evidenciar uma variabilidade significativa local, bem como regional no Estado do Ceará.In the context of water resources scarcity, the rational use of water for irrigation is necessary, implying precise estimations of the actual evapotranspiration (ET. With the recent progresses of remote-sensed technologies, regional algorithms estimating evapotranspiration from satellite observations were developed. This work aimed at applying the SEBAL algorithm (Surface Energy Balance Algorithms for Land at three Landsat-5 images during the second semester of 2006. These images cover irrigated areas, dense native forest areas and caatinga areas in three regions of the state of Ceará (Baixo Acaraú, Chapada do Apodi and Chapada do Araripe. The SEBAL algorithm calculates the hourly evapotranspiration from the latent heat flux, estimated from the surface energy

Detección de daños en estructuras: estudio comparativo entre los algoritmos de optimización AGs y PSO

Directory of Open Access Journals (Sweden)

Robinson Barrera

2014-01-01

Full Text Available En este artículo se comparan las técnicas de optimización de enjambre de partículas, PSO (de sus siglas en inglés, Particle Swarm Optimization y Algoritmos Genéticos (AG, ambas usadas en la implementación de un sistema para detectar y diagnosticar fallas en una estructura usando la respuesta modal. Diferentes episodios de daños (daño simple y daño múltiple con y sin ruido, permiten simular las condiciones reales en una estructura tipo viga y armadura para determinar el desempeño en la detección y diagnóstico de los sistemas propuestos. Adicionalmente, ambos sistemas propuestos se evalúan variando los volúmenes de información, es decir, el número de modos de vibración. La respuesta dinámica de la estructura en condición normal o de falla se obtiene usando la herramienta de uso libre OPENSEES® y los algoritmos de optimización PSO y AGs se implementan en ambiente Matlab®. La comparación de desempeño de las dos técnicas en cuanto a sus capacidades de detección y diagnóstico se realizan en una viga segmentada en 10 partes y simplemente apoyada y una armadura de 13 elementos. Resultados experimentales mostraron la eficacia y robustez de los sistemas propuestos en la determinación del estado del sistema en diversos ambientes de ruido y con diferentes volúmenes de información. Sin embargo su desempeño varía según el sistema monitoreado y la función objetivo utilizada

Usando algoritmos e ábaco no estudo do sistema de numeração decimal em um curso de Pedagogia

Directory of Open Access Journals (Sweden)

Viegas, Elis Regina dos Santos

2015-05-01

Full Text Available Studies in Mathematics Education have described difficulties of teachers in the use of algorithms in arithmetic teaching in the initial grades, difficulties leading to questions about the quality of theoretical and practical training provided for teachers in this area. In this context, the present study aimed to investigate the formation of concepts and construction of mathematical knowledge of Pedagogy students in relation to arithmetic teaching, basic operations using abacus and algorithms, as well as the decimal numbering system. In the theoretical approach, the authors reflect on initial teacher training for Mathematics teachers in the initial grades, the necessity of training grounded in knowledge to the process of teaching/learning and the importance of teacher training in methodological contents and in specific contents. A qualitative and quantitative approach was used, the data collection occurred with the use of semi-structured questionnaires, procedures in the activities report, direct observation and video recording. The results showed that studies with both methodological approaches, abacus and algorithms, might contribute to the formation, reframing concepts and construction of mathematical knowledge, but also could provide information for a better pedagogical and specific training. Estudos em Educação Matemática têm descrito dificuldades de professores na utilização de algoritmos no ensino de aritmética nas séries iniciais, dificuldades que provocam questionamentos quanto à qualidade da formação teórico-prática oferecida para a docência nessa área. Nesse contexto, o presente estudo teve como objetivo investigar a formação de conceitos e construção do conhecimento matemático de estudantes de Pedagogia em relação ao ensino de aritmética, das operações fundamentais com a utilização de ábaco e algoritmos, bem como, do sistema de numeração decimal. No referencial teórico adotado, os autores refletem sobre

DESIGN OF ALGORITHMS BASED ON BEHAVIOUR FOR THE CONTROL OF MINIBOTS // DISEÑO DE ALGORITMOS BASADOS EN COMPORTAMIENTOS PARA EL CONTROL DE MINIBOTS

Directory of Open Access Journals (Sweden)

Maritza Bracho de Rodríguez

2012-12-01

Full Text Available Using the Distributed Artificial Intelligence and the Distributed Robotics as a frame of reference, in this work are designed, developed and implemented algorithms to control autonomous, mobile, reactive, rational, proactive and sociable small robots. These minibots are capable to exhibit behaviors inspired in biological societies. Through the development of this work it was found that if the robot has to perform simple tasks, a reactive architecture is more convenient, efficient and effective. While for the performance of tasks of medium or greater complexity, is recommend the use of a hybrid architecture that allows the incorporation of deliberative reasoning.// RESUMEN: Tomando como marco de referencia a la Inteligencia Artificial Distribuida y la Robótica Distribuida, en este trabajo se diseñan, desarrollan e implementan algoritmos para el control de pequeños robots autónomos, móviles, reactivos, racionales, proactivos y sociables. Estos minibots son capaces de exhibir comportamientos inspirados en las sociedades biológicas. En los resultados alcanzados durante el desarrollo de este trabajo se encontró que cuando el robot debe ejecutar tareas simples, la arquitectura reactiva es la más conveniente, eficiente y efectiva, mientras que para la ejecución de tareas de complejidad mediana o mayor, es más recomendable el uso de arquitecturas hibridas que permitan la incorporación de procesos deliberativos.

Aplicación de algoritmos metaheurísticos en procesamiento de señales, imágenes y energías alternativas

OpenAIRE

Oliva Navarro, Diego Alberto

2016-01-01

En años recientes se ha incrementado el interés por cómo la naturaleza da solución a diversos problemas como son: búsqueda de fuentes de alimento, organización de conjuntos de animales o insectos, atracción y repulsión de cargas, etc. De aquí surgen los algoritmos metaheurísticos (AM), los cuales simulan comportamientos naturales básicos para solucionar tareas complejas. El uso de estos métodos se ha extendido desde la optimización matemática hasta la ingeniería o la economía.En este trabajo ...

Highly efficient electron vortex beams generated by nanofabricated phase holograms

Energy Technology Data Exchange (ETDEWEB)

Grillo, Vincenzo, E-mail: vincenzo.grillo@nano.cnr.it [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); CNR-IMEM Parco Area delle Scienze 37/A, I-43124 Parma (Italy); Carlo Gazzadi, Gian [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Karimi, Ebrahim [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Mafakheri, Erfan [Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy); Boyd, Robert W. [Department of Physics, University of Ottawa, 150 Louis Pasteur, Ottawa, Ontario K1N 6N5 (Canada); Frabboni, Stefano [CNR-Istituto Nanoscienze, Centro S3, Via G Campi 213/a, I-41125 Modena (Italy); Dipartimento di Fisica Informatica e Matematica, Università di Modena e Reggio Emilia, via G Campi 213/a, I-41125 Modena (Italy)

2014-01-27

We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

Highly efficient electron vortex beams generated by nanofabricated phase holograms

International Nuclear Information System (INIS)

Grillo, Vincenzo; Carlo Gazzadi, Gian; Karimi, Ebrahim; Mafakheri, Erfan; Boyd, Robert W.; Frabboni, Stefano

2014-01-01

We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science

Análisis y estudio de las técnicas de compresión de datos para la integración de la tecnología PDH/SDH sobre redes ethernet e implementación de un algoritmo de compresión mediante software de simulación

OpenAIRE

Gálvez Castillo, Juan Carlos; Morocho Vallejo, Luis Roberto

2010-01-01

El presente Proyecto de Grado, titulado: Análisis y estudio de las técnicas de compresión de datos para la integración de la tecnología PDH/SDH sobre redes Ethernet e implementación de un algoritmo de compresión mediante software de simulación, comprende un estudio investigativo de las características, ventajas y desventajas de las técnicas de compresión de datos, comprende también de la implementación de un algoritmo de compresión que demuestre mediante un software de simulación dichas venta...

Techno-Economic Feasibility of Highly Efficient Cost-Effective Thermoelectric-SOFC Hybrid Power Generation Systems

Energy Technology Data Exchange (ETDEWEB)

Jifeng Zhang; Jean Yamanis

2007-09-30

Solid oxide fuel cell (SOFC) systems have the potential to generate exhaust gas streams of high temperature, ranging from 400 to 800 C. These high temperature gas streams can be used for additional power generation with bottoming cycle technologies to achieve higher system power efficiency. One of the potential candidate bottoming cycles is power generation by means of thermoelectric (TE) devices, which have the inherent advantages of low noise, low maintenance and long life. This study was to analyze the feasibility of combining coal gas based SOFC and TE through system performance and cost techno-economic modeling in the context of multi-MW power plants, with 200 kW SOFC-TE module as building blocks. System and component concepts were generated for combining SOFC and TE covering electro-thermo-chemical system integration, power conditioning system (PCS) and component designs. SOFC cost and performance models previously developed at United Technologies Research Center were modified and used in overall system analysis. The TE model was validated and provided by BSST. The optimum system in terms of energy conversion efficiency was found to be a pressurized SOFC-TE, with system efficiency of 65.3% and cost of $390/kW of manufacturing cost. The pressurization ratio was approximately 4 and the assumed ZT of the TE was 2.5. System and component specifications were generated based on the modeling study. The major technology and cost barriers for maturing the system include pressurized SOFC stack using coal gas, the high temperature recycle blowers, and system control design. Finally, a 4-step development roadmap is proposed for future technology development, the first step being a 1 kW proof-of-concept demonstration unit.

Generating Private Recommendations Efficiently Using Homomorphic Encryption and Data Packing

DEFF Research Database (Denmark)

Erkin, Zekeriya; Veugen, Thijs; Toft, Tomas

2012-01-01

Recommender systems have become an important tool for personalization of online services. Generating recommendations in online services depends on privacy-sensitive data collected from the users. Traditional data protection mechanisms focus on access control and secure transmission, which provide...... them under encryption to generate recommendations. By introducing a semitrusted third party and using data packing, we construct a highly efficient system that does not require the active participation of the user. We also present a comparison protocol, which is the first one to the best of our...... security only against malicious third parties, but not the service provider. This creates a serious privacy risk for the users. In this paper, we aim to protect the private data against the service provider while preserving the functionality of the system. We propose encrypting private data and processing...

An Efficient Expert System Generator for Qualitative Feed-Back Loop Analysis

Directory of Open Access Journals (Sweden)

Manoj Kumar Jain

2012-04-01

Full Text Available Quite often the variables used in system analysis are qualitative in nature. They cannot be defined precisely, whereas software development for system analysis needs a mathematical framework with precise computations. It is not trivial to capture the uncertainty in the system.
Fuzzy sets provide us the facility to capture the uncertainty in the system. In normal crisp set where the membership of an element is always certain in a sense that it would be member or not of the given set. In contrast to this a membership functions or possibility (ranging from 0 to 1, including both values is assigned with each member. System analysis is done through system dynamics which is not very efficient. We present an efficient technique to generate expert system using fuzzy set. In our proposed approach five linguistic qualifiers are used for each variable, namely, Very Low (VL, Low (L, Medium (M, High (H, and Very High
(VH. We capture the influence or feedback in the system with the help of if then else rules and matrices are generated for them which are used for analysis. Complete methodology and its applicability are presented here.

Efficient generation of connectivity in neuronal networks from simulator-independent descriptions

Directory of Open Access Journals (Sweden)

Mikael eDjurfeldt

2014-04-01

Full Text Available Simulator-independent descriptions of connectivity in neuronal networks promise greater ease of model sharing, improved reproducibility of simulation results, and reduced programming effort for computational neuroscientists. However, until now, enabling the use of such descriptions in a given simulator in a computationally efficient way has entailed considerable work for simulator developers, which must be repeated for each new connectivity-generating library that is developed.We have developed a generic connection generator interface that provides a standard way to connect a connectivity-generating library to a simulator, such that one library can easily be replaced by another, according to the modeller's needs. We have used the connection generator interface to connect C++ and Python implementations of the connection-set algebra to the NEST simulator. We also demonstrate how the simulator-independent modelling framework PyNN can transparently take advantage of this, passing a connection description through to the simulator layer for rapid processing in C++ where a simulator supports the connection generator interface and falling-back to slower iteration in Python otherwise. A set of benchmarks demonstrates the good performance of the interface.

Desarrollo de una aplicación para la gestión, clasificación y agrupamiento de documentos económicos con algoritmos bio-inspirados

OpenAIRE

Cobo Ortega, Ángel; Rocha Blanco, Eliana Rocío

2007-01-01

Este trabajo describe el desarrollo de una aplicación Web que utiliza técnicas bio-inspiradas para clasificar y agrupar colecciones multilingües de documentos en el campo de la economía y los negocios. La aplicación identifica grupos relacionados de documentos económicos, escritos en español e ingles, utilizando algoritmos de clustering inspirados en el comportamiento de las colonias de hormigas. Para la generación de una representación vectorial de los documentos que resulte independiente de...

Aplicações e algoritmos de segurança rodoviária com o uso de sistemas de GPS e de comunicações WAVE

OpenAIRE

Cardoso, Fábio

2013-01-01

Trabalho Final de Mestrado para obtenção do grau de Mestre em Engenharia de Electrónica e Telecomunicações Os acidentes rodoviários são um problema de grande importância para toda a humanidade. O objetivo desta tese é desenvolver um sistema, através de comunicação WAVE, vehicle-tovehicle, capaz de alertar os automobilistas de risco de colisões. O sistema desenvolvido utiliza os dados recebidos por um sistema de GPS para o processamento dos algoritmos de segurança, estudados no estado ...

Distributed generation, storage, demand response and energy efficiency as alternatives to grid capacity enhancement

International Nuclear Information System (INIS)

Poudineh, Rahmatallah; Jamasb, Tooraj

2014-01-01

The need for investment in capital intensive electricity networks is on the rise in many countries. A major advantage of distributed resources is their potential for deferring investments in distribution network capacity. However, utilizing the full benefits of these resources requires addressing several technical, economic and regulatory challenges. A significant barrier pertains to the lack of an efficient market mechanism that enables this concept and also is consistent with business model of distribution companies under an unbundled power sector paradigm. This paper proposes a market-oriented approach termed as “contract for deferral scheme” (CDS). The scheme outlines how an economically efficient portfolio of distributed generation, storage, demand response and energy efficiency can be integrated as network resources to reduce the need for grid capacity and defer demand driven network investments. - Highlights: • The paper explores a practical framework for smart electricity distribution grids. • The aim is to defer large capital investments in the network by utilizing and incentivising distributed generation, demand response, energy efficiency and storage as network resources. • The paper discusses a possible new market model that enables integration of distributed resources as alternative to grid capacity enhancement

A PVTC system integrating photon-enhanced thermionic emission and methane reforming for efficient solar power generation

Institute of Scientific and Technical Information of China (English)

Wenjia Li; Hongsheng Wang; Yong Hao

2017-01-01

A new photovoltaic-thermochemical (PVTC) conceptual system integrating photon-enhanced thermionic emission (PETE) and methane steam reforming is proposed.Major novelty of the system lies in its potential adaptivity to primary fuels (e.g.methane) and high efficiencies of photovoltaic and thermochemical power generation,both of which result from its operation at much elevated temperatures (700-1000 ℃)compared with conventional photovoltaic-thermal (PVT) systems.Analysis shows that an overall power generation efficiency of 45.3％ and a net solar-to-electric efficiency of 39.1％ could be reached at an operating temperature of 750 ℃,after considering major losses during solar energy capture and conversion processes.The system is also featured by high solar share (37％) in the total power output,as well as high energy storage capability and very low CO2 emissions,both enabled by the integration of methane reforming with photovoltaic generation at high temperatures.

Does environmental regulation affect energy efficiency in China's thermal power generation? Empirical evidence from a slacks-based DEA model

International Nuclear Information System (INIS)

Bi, Gong-Bing; Song, Wen; Zhou, P.; Liang, Liang

2014-01-01

Data envelopment analysis (DEA) has gained much popularity in performance measurement of power industry. This paper presents a slack-based measure approach to investigating the relationship between fossil fuel consumption and the environmental regulation of China's thermal power generation. We first calculate the total-factor energy efficiency without considering environmental constraints. An environmental performance indicator is proposed through decomposing the total-factor energy efficiency. The proposed approach is then employed to examine whether environmental regulation affects the energy efficiency of China's thermal power generation. We find that the environmental efficiency plays a significant role in affecting energy performance of China's thermal generation sector. Decreasing the discharge of major pollutants can improve both energy performance and environmental efficiency. Besides, we also have three main findings: (1) The energy efficiency and environmental efficiency were relatively low. (2) The energy and environmental efficiency scores show great variations among provinces. (3) Both energy efficiency and environmental efficiency are of obvious geographical characteristics. According to our findings, we suggest some policy implications. - Highlights: • We assess the energy efficiency and the environmental efficiency of China's thermal power generation simultaneously. • The energy efficiency and the environmental efficiency were relatively low during 2007–2009. • The energy efficiency and environmental efficiency show obvious geographic characters. • The environmental performance of a DMU plays a decisive role in the energy performance

High-efficiency target-ion sources for RIB generation

International Nuclear Information System (INIS)

Alton, G.D.

1993-01-01

A brief review is given of high-efficiency ion sources which have been developed or are under development at ISOL facilities which show particular promise for use at existing, future, or radioactive ion beam (RIB) facilities now under construction. Emphasis will be placed on those sources which have demonstrated high ionization efficiency, species versatility, and operational reliability and which have been carefully designed for safe handling in the high level radioactivity radiation fields incumbent at such facilities. Brief discussions will also be made of the fundamental processes which affect the realizable beam intensities in target-ion sources. Among the sources which will be reviewed will be selected examples of state-of-the-art electron-beam plasma-type ion sources, thermal-ionization, surface-ionization, ECR, and selectively chosen ion source concepts which show promise for radioactive ion beam generation. A few advanced, chemically selective target-ion sources will be described, such as sources based on the use of laser-resonance ionization, which, in principle, offer a more satisfactory solution to isobaric contamination problems than conventional electromagnetic techniques. Particular attention will be given to the sources which have been selected for initial or future use at the Holifield Radioactive Ion Beam Facility now under construction at the Oak Ridge National Laboratory

Algoritmo de recocido simulado para la descomposición robusta del horizonte de tiempo en problemas de planeación de producción A simulated annealing algorithm for the robust decomposition of temporal horizons in production planning problems

Directory of Open Access Journals (Sweden)

José Fidel Torres Delgado

2007-06-01

Full Text Available El problema de la descomposición robusta del horizonte de tiempo en planeación de producción fue inicialmente tratado en [1]. Posteriormente, en [2], Torres propone partir de una solución entera encontrada por programación dinámica, para luego mejorarla mediante un algoritmo de recocido simulado(simulated annealing. De acuerdo con [2], es necesario investigar más a fondo la capacidad de este algoritmo para mejorar la solución inicial y el impacto de la selección de los parámetros de control del algoritmo sobre la calidad de las soluciones encontradas. En este trabajo se desarrolla esta propuesta de analizar más a fondo la capacidad del algoritmo de recocido simulado para mejorar la solución inicial. Como resultado de los experimentos computacionales realizados, se determinó que el método de enfriamiento y la tasa de enfriamiento tienen efecto significativo en la calidad de la solución final. De igual manera se estableció que la solución depende en gran medida de las características del plan de operaciones, encontrándose mejores soluciones para planes con horizontes de tiempo más cortos.The problem of robust decomposition of temporal horizons in production planning was first introduced by Torres [1]. Later, in [2], Torres suggests to start with an integer solution found by dynamic programming, and then to use a simulated annealing algorithm to improve it. According to [2], more needs to be known about the impact of the control parameters in the simulated annealing algorithm, and their sensitivity with respect to the quality of the solutions. In this work we develop this idea and analyze in depth the ability of the simulated annealing algorithm to improve the initial solution. As a result of the computational experiments conducted, we determined that the cooling scheme and the cooling rate have significant effect on the quality of the final solution. It was also established that the solution found depends strongly on the

Power generation efficiency of an SOFC-PEFC combined system with time shift utilization of SOFC exhaust heat

Energy Technology Data Exchange (ETDEWEB)

Obara, Shin' ya [Power Engineering Lab., Department of Electrical and Electronic Engineering, Kitami Institute of Technology, 165 Kouen-cho, Kitami, Hokkaido 0908507 (Japan)

2010-01-15

A microgrid, with little environmental impact, is developed by introducing a combined SOFC (solid oxide fuel cell) and PEFC (proton exchange membrane fuel cell) system. Although the SOFC requires a higher operation temperature compared to the PEFC, the power generation efficiency of the SOFC is higher. However, if high temperature exhaust heat may be used effectively, a system with higher total power generation efficiency can be built. Therefore, this paper investigates the operation of a SOFC-PEFC combined system, with time shift operation of reformed gas, into a microgrid with 30 houses in Sapporo, Japan. The SOFC is designed to correspond to base load operation, and the exhaust heat of the SOFC is used for production of reformed gas. This reformed gas is used for the production of electricity for the PEFC, corresponding to fluctuation load of the next day. Accordingly, the reformed gas is used with a time shift operation. In this paper, the relation between operation method, power generation efficiency, and amount of heat storage of the SOFC-PEFC combined system to the difference in power load pattern was investigated. The average power generation efficiency of the system can be maintained at nearly 48% on a representative day in February (winter season) and August (summer season). (author)

ESTIMACIÓN ROBUSTA DE MODELOS ADITIVOS MEDIANTE EL ALGORITMO DE BACKFITTING

Directory of Open Access Journals (Sweden)

Luis P. Yapu Quispe

2012-07-01

Full Text Available En este trabajo se presenta un método de estimación y simulación de un modelo aditivo a dos variables mediante splines robustos, el método general puede ser aplicado con varias variables. El software utilizado para las simulaciones es S+ y se utiliza explícitamente la función smooth.splineRob en una implementación del algoritmo de backfitting. La función smooth.splineRob ha sido escrita en base al trabajo de Cantoni y Ronchetti [3], en el cual se pone énfasis en la selección robusta del parámetro de suavizamiento utilizando una versión robusta del Cp de Mallows, RCp, y de la validación cruzada, RCV. La existencia de datos extremos o no-normales en la parte estocástica de un modelo aditivo puede provocar una mala estimación del parámetro de suavizamiento, lo que tendrá influencia global en la estimación por splines. Para la etapa de simulación se realizan las estimaciones por splines clásicos y robustos (con estimación robusta del parámetro. La estimación obtenida es muy convincente pero el tiempo de ejecución del programa es relativamente elevado tanto para RCp y RCV, aun cuando, en ciertos casos, con pocas iteraciones robustas se obtienen ya resultados más útiles que la estimación clásica.

An efficient linear power generator - Linear motor for oscillating piston machines; Effizienter Lineargenerator / Linearmotor fuer Kolbenmaschine - Schlussbericht

Energy Technology Data Exchange (ETDEWEB)

Lindegger, M.

2008-07-01

When an oscillating piston interacts with an electrical generator or motor, it is obvious that the electrical machine should also have linear motion, eliminating the disadvantage of a crankshaft. This work has two parts: construction of an efficient linear generator for a Stirling engine with a free piston and a theoretical study of the efficiency of linear motors for driving compressors. The Stirling engine and the linear generator have a continuous power of 1.3 kW{sub el}. With thermal peak power the planned 1.5 kW{sub el} are attained. The Project 'Stirling Free Piston Generator' for cogeneration will continue. Smaller linear motors with permanent magnets function without electronic control from single-phase AC net. The theoretical study shows how linear motors can be led out by linking the electric vector diagram with the pressure-volume diagram of the compressor. At a power level exceeding a few kW, a three-phase system with power electronics is more suitable. The frequency of oscillation is variable and lower than 50 Hz. The efficiency of the simulated linear motors lies in the range of efficiency class EFF1 of standard motors. The very high efficiencies of rotating motors with permanent magnets are not attained. The combination of the linear motor with an optimised thermal process leads to advantages regarding the efficiency. If a heat pump with linear drive system can operate with hot lubricating oil the losses in the heat exchangers are reduced. The Competence Center for Thermal Machines at Lucerne University of Applied Sciences and Arts shows great interest to pursue the project of a linear heat pump for small temperature differences. (author)

Oxygen blast furnace and combined cycle (OBF-CC) - an efficient iron-making and power generation process

International Nuclear Information System (INIS)

Jianwei, Y.; Guolong, S.; Cunjiang, K.; Tianjun, Y.

2003-01-01

A new iron and power generating process, oxygen blast furnace and combined cycle (OBF-CC), is presented. In order to support the opinion, the features of the oxygen blast furnace and integrated coal gasification and combined cycle (IGCC) are summarized. The relation between the blasting parameters and the output gas quantity, as well as caloric value is calculated based on mass and energy balance. Analysis and calculation indicate that the OBF-CC will be an efficient iron-making and power generation process with higher energy efficiency and less pollution

TU-AB-BRA-02: An Efficient Atlas-Based Synthetic CT Generation Method

International Nuclear Information System (INIS)

Han, X

2016-01-01

Purpose: A major obstacle for MR-only radiotherapy is the need to generate an accurate synthetic CT (sCT) from MR image(s) of a patient for the purposes of dose calculation and DRR generation. We propose here an accurate and efficient atlas-based sCT generation method, which has a computation speed largely independent of the number of atlases used. Methods: Atlas-based sCT generation requires a set of atlases with co-registered CT and MR images. Unlike existing methods that align each atlas to the new patient independently, we first create an average atlas and pre-align every atlas to the average atlas space. When a new patient arrives, we compute only one deformable image registration to align the patient MR image to the average atlas, which indirectly aligns the patient to all pre-aligned atlases. A patch-based non-local weighted fusion is performed in the average atlas space to generate the sCT for the patient, which is then warped back to the original patient space. We further adapt a PatchMatch algorithm that can quickly find top matches between patches of the patient image and all atlas images, which makes the patch fusion step also independent of the number of atlases used. Results: Nineteen brain tumour patients with both CT and T1-weighted MR images are used as testing data and a leave-one-out validation is performed. Each sCT generated is compared against the original CT image of the same patient on a voxel-by-voxel basis. The proposed method produces a mean absolute error (MAE) of 98.6±26.9 HU overall. The accuracy is comparable with a conventional implementation scheme, but the computation time is reduced from over an hour to four minutes. Conclusion: An average atlas space patch fusion approach can produce highly accurate sCT estimations very efficiently. Further validation on dose computation accuracy and using a larger patient cohort is warranted. The author is a full time employee of Elekta, Inc.

Optimization of a water resource system expansion using the Genetic Algorithm and Simulated Annealing methods; Optimizacion de la expansion de un sistema de recursos hidricos utilizados las metodologias del algoritmo genetico y el recocido simulado

Energy Technology Data Exchange (ETDEWEB)

Sanchez Camacho, Enrique; Andreu Alvarez, Joaquin [Universidad Politecnica de Valencia (Spain)

2001-06-01

Two numerical procedures, based on the Genetic Algorithm (GA) and the Simulated Annealing (SA), are developed to solve the problem of the expansion of capacity of a water resource system. The problem was divided into two subproblems: capital availability and operation policy. Both are optimisation-simulation models, the first one is solved by means of the GA and SA, in each case, while the second one is solved using the Out-of-kilter algorithm (OKA), in both models. The objective function considers the usual benefits and costs in this kind of systems, such as irrigation and hydropower benefits, costs of dam construction and system maintenance. The strength and weakness of both models are evaluated by comparing their results with those obtained with the branch and bound technique, which was classically used to solve this kind of problems. [Spanish] Un par de metodos numericos fundamentados en dos tecnicas de busqueda globales. Algoritmos Genetico (AG) y Recocido Simulado (RS), son desarrollados para resolver el problema de expansion de capacidad de un sistema de recursos hidricos. La estrategia ha sido dividir al problema en dos subproblemas: el de disponibilidad de capital y el de la politica de operacion. Ambos modelos son de optimizacion-simulacion, el primero se realiza mediante los algoritmos del RS y el AG en cada caso, en tanto que el segundo lleva a cabo a traves del algoritmo del Out-of-kilter (AOK) en los dos modelos. La funcion objetivo con que se trabaja considera los beneficios y costos mas comunes en este tipo de sistema, tales como beneficios por riego, por hidroelectricidad y costos de construccion de los embalses y mantenimiento del sistema. La potencia y debilidades delos dos modelos se evaluan mediante la comparacion con los resultados obtenidos a traves de una de las tecnicas mas usadas en este tipo de problemas: la de ramificacion y acotacion.

Distribución óptima de carga en emplazamientos de generadores; Optimal charging distribution in emplacements of generators

Directory of Open Access Journals (Sweden)

Sergio de la Fé Dotres

2014-04-01

Full Text Available Incorporados al Sistema Eletroenergético Nacional funcionan emplazamientos de generación distribuida que representan más del 40 por ciento de la capacidad generadora instalada. Estos grupo utilizan fuel oil o diesel como combustibles por lo que lograr su explotación eficiente constituye una necesidad económica de primer orden. Se propone un instrumento computacional para lograr la mayor eficiencia en el uso del combustible mediante la distribución económica de las cargas y se desarrolla un método de optimización basado en el criterio del costo incremental del combustible para determinar el costo total de la generación del emplazamiento. Empleando un algoritmo genético simple se minimiza la función del costo mediante la asignación de las potencias a generar por cada máquina. Se comprueba la aplicabilidad del método mediante su aplicación a un emplazamiento específico. Por su rapidez y calidad de los resultados el instrumento computacional se recomienda para su explotación en emplazamientos y el despacho.  The emplacements of distributed generation that represent over the 40 percent of the generating installed capability work to the electric national system incorporated. These group Fuel Oil or diesel utilize like fuels for that achieving his efficient exploitation constitutes a need cheap to run first-rate. Distribution cheap to run of loads proposes a computational instrument to achieve the bigger efficiency in the use of intervening fuel itself and a method of optimization based in the opinion of the incremental cost of fuel to determine the total cost of the generation of the emplacement develops. Using a genetic algorithm the assignment of potencies minimizes the show of the intervening cost itself to generate for each machine. His application finds to a specific summons the applicability of the intervening method. For his rapidity and quality of results the computational instrument is recommended to exploitation in

Comparação dos algoritmos delineação rápida em cadeia e seriação, para a construção de mapas genéticos Comparison of algorithms rapid chain delineation and seriation, for the construction of genetic linkage maps

Directory of Open Access Journals (Sweden)

Marcelo Mollinari

2008-04-01

Full Text Available O objetivo deste trabalho foi avaliar a eficiência, na construção de mapas genéticos, dos algoritmos seriação e delineação rápida em cadeia, além dos critérios para avaliação de ordens: produto mínimo das frações de recombinação adjacentes, soma mínima das frações de recombinação adjacentes e soma máxima dos LOD Scores adjacentes, quando usados com o algoritmo de verificação de erros " ripple" . Foi simulado um mapa com 24 marcadores, posicionados aleatoriamente a distâncias variadas, com média 10 cM. Por meio do método Monte Carlo, foram obtidas 1.000 populações de retrocruzamento e 1.000 populações F2, com 200 indivíduos cada, e diferentes combinações de marcadores dominantes e co-dominantes (100% co-dominantes, 100% dominantes e mistura com 50% co-dominantes e 50% dominantes. Foi, também, simulada a perda de 25, 50 e 75% dos dados. Observou-se que os dois algoritmos avaliados tiveram desempenho semelhante e foram sensíveis à presença de dados perdidos e à presença de marcadores dominantes; esta última dificultou a obtenção de estimativas com boa acurácia, tanto da ordem quanto da distância. Além disso, observou-se que o algoritmo " ripple" geralmente aumenta o número de ordens corretas e pode ser combinado com os critérios soma mínima das frações de recombinação adjacentes e produto mínimo das frações de recombinação adjacentes.The objective of this work was to evaluate the efficiency for the construction of genetic linkage maps of the algorithms seriation and rapid chain delineation, as well as the criteria: product of adjacent recombination fractions, sum of adjacent recombination fractions, and sum of adjacent LOD Scores, used with the ripple algorithm. A genetic linkage map was simulated containing 24 markers with random distances between them, with an average of 10 cM. Using the Monte Carlo method, 1,000 backcross populations and 1,000 F2 populations were simulated. The

Efficient generation of integration-free human induced pluripotent stem cells from keratinocytes by simple transfection of episomal vectors.

Science.gov (United States)

Piao, Yulan; Hung, Sandy Shen-Chi; Lim, Shiang Y; Wong, Raymond Ching-Bong; Ko, Minoru S H

2014-07-01

Keratinocytes represent an easily accessible cell source for derivation of human induced pluripotent stem (hiPS) cells, reportedly achieving higher reprogramming efficiency than fibroblasts. However, most studies utilized a retroviral or lentiviral method for reprogramming of keratinocytes, which introduces undesirable transgene integrations into the host genome. Moreover, current protocols of generating integration-free hiPS cells from keratinocytes are mostly inefficient. In this paper, we describe a more efficient, simple-to-use, and cost-effective method for generating integration-free hiPS cells from keratinocytes. Our improved method using lipid-mediated transfection achieved a reprogramming efficiency of ∼0.14% on average. Keratinocyte-derived hiPS cells showed no integration of episomal vectors, expressed stem cell-specific markers and possessed potentials to differentiate into all three germ layers by in vitro embryoid body formation as well as in vivo teratoma formation. To our knowledge, this represents the most efficient method to generate integration-free hiPS cells from keratinocytes. ©AlphaMed Press.

Integration of direct carbon and hydrogen fuel cells for highly efficient power generation from hydrocarbon fuels

Energy Technology Data Exchange (ETDEWEB)

Muradov, Nazim; Choi, Pyoungho; Smith, Franklyn; Bokerman, Gary [Florida Solar Energy Center, University of Central Florida, 1679 Clearlake Road, Cocoa, FL 32922-5703 (United States)

2010-02-15

In view of impending depletion of hydrocarbon fuel resources and their negative environmental impact, it is imperative to significantly increase the energy conversion efficiency of hydrocarbon-based power generation systems. The combination of a hydrocarbon decomposition reactor with a direct carbon and hydrogen fuel cells (FC) as a means for a significant increase in chemical-to-electrical energy conversion efficiency is discussed in this paper. The data on development and operation of a thermocatalytic hydrocarbon decomposition reactor and its coupling with a proton exchange membrane FC are presented. The analysis of the integrated power generating system including a hydrocarbon decomposition reactor, direct carbon and hydrogen FC using natural gas and propane as fuels is conducted. It was estimated that overall chemical-to-electrical energy conversion efficiency of the integrated system varied in the range of 49.4-82.5%, depending on the type of fuel and FC used, and CO{sub 2} emission per kW{sub el}h produced is less than half of that from conventional power generation sources. (author)

Next generation of high-efficient waste incinerators. Final report

Energy Technology Data Exchange (ETDEWEB)

Jappe Frandsen, F.

2010-11-15

Modern society produces increasing amounts of combustible waste which may be utilized for heat and power production, at a lower emission of CO{sub 2}, e.g. by substituting a certain fraction of energy from fossil fuel-fired power stations. In 2007, 20.4 % of the district heating and 4.5 % of the power produced in Denmark came from thermal conversion of waste, and waste is a very important part of a future sustainable, and independent, Danish energy supply [Frandsen et al., 2009; Groen Energi, 2010]. In Denmark, approx 3.3 Mtons of waste was produced in 2005, an amount predicted to increase to 4.4 Mtons by the year 2030. According to Affald Danmark, 25 % of the current WtE plant capacity in Denmark is older than 20 years, which is usually considered as the technical and economical lifetime of WtE plants. Thus, there is a need for installation of a significant fraction of new waste incineration capacity, preferentially with an increased electrical efficiency, within the next few years. Compared to fossil fuels, waste is difficult to handle in terms of pre-treatment, combustion, and generation of reusable solid residues. In particular, the content of inorganic species (S, Cl, K, Na, etc.) is problematic, due to enhanced deposition and corrosion - especially at higher temperatures. This puts severe constraints on the electrical efficiency of grate-fired units utilizing waste, which seldom exceeds 26-27%, campared to 46-48 % for coal combustion in suspension. The key parameters when targeting higher electrical efficiency are the pressure and temperature in the steam cycle, which are limited by high-temperature corrosion, boiler- and combustion-technology. This report reviews some of the means that can be applied in order to increase the electrical efficiency in plants firing waste on a grate. (Author)

Thermal cycle efficiency of the indirect combined HTGR-GT power generation system

Energy Technology Data Exchange (ETDEWEB)

Muto, Yasushi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1996-02-01

High thermal efficiency of 50% could be expected in a power generation system coupling a high temperature gas-cooled reactor(HTGR) with a closed cycle gas turbine(GT). There are three candidate systems such as a direct cycle(DC), an indirect cycle(ICD) and an indirect combined cycle(IDCC). The IDCC could solve many problems in both the DC and the IDC and consists of a primary circuit and a secondary circuit where a topping cycle is a Brayton cycle and a bottoming cycle is a steam cycle. In this report, the thermal cycle efficiency of the IDCC is examined regarding configurations of components and steam pressure. It has been shown that there are two types of configurations, that is, a perfect cascade type and a semi-cascade one and the latter can be further classified into Case A, Case B and Case C. The conditions achieving the maximum thermal cycle efficiency were revealed for these cases. In addition, the optimum system configurations were proposed considering the thermal cycle efficiency, safety and plant arrangement. (author).

Algoritmos Evolutivos y su empleo en el ajuste de controladores del tipo PID: Estado Actual y Perspectivas

Directory of Open Access Journals (Sweden)

Gilberto Reynoso-Meza

2013-07-01

Full Text Available Resumen: Los controladores PID continúan siendo una solución fiable, robusta, práctica y sencilla para el control de procesos. Actualmente constituyen la primera capa de control de la gran mayoría de las aplicaciones industriales. De ahí que un número importante de trabajos de investigación se han orientado a mejorar su rendimiento y prestaciones. Las líneas de investigación en este campo van desde nuevos métodos de ajuste, pasando por nuevos tipos de estructura hasta metodologías de diseño integrales. Particularizando en el ajuste de parámetros, una de las formas de obtener una solución novedosa consiste en plantear un problema de optimización, el cual puede llegar a ser no-lineal, no-convexo y con restricciones. Dado que los algoritmos evolutivos han mostrado un buen desempeño para solucionar problemas complejos de optimización, han sido utilizados en diversas propuestas relacionadas con el ajuste de controladores PID. Este trabajo muestra un revisión de estas propuestas y las prestaciones obtenidas en cada caso. Así mismo, se identifican algunas tendencias y posibles líneas de trabajo futuras. Abstract: PID controllers are a reliable, robust, practical and easy to implement control solution for industrial processes. They provide the first control layer for a vast majority of industrial applications. Owing to this, several researches invest time and resources to improve their performance. The research lines in this field scope with new tuning methods, new types of structures and integral design methods. For tuning methods, improvements could be fulfilled stating an optimization problem, which could be non-linear, non-convex and highly constrained. In such instances, evolutionary algorithms have shown a good performance and have been used in various proposals related with PID controllers tuning. This work shows a review of these proposals and the benefits obtained in each case. Some

Dye-sensitized solar cells for efficient power generation under ambient lighting

Science.gov (United States)

Freitag, Marina; Teuscher, Joël; Saygili, Yasemin; Zhang, Xiaoyu; Giordano, Fabrizio; Liska, Paul; Hua, Jianli; Zakeeruddin, Shaik M.; Moser, Jacques-E.; Grätzel, Michael; Hagfeldt, Anders

2017-06-01

Solar cells that operate efficiently under indoor lighting are of great practical interest as they can serve as electric power sources for portable electronics and devices for wireless sensor networks or the Internet of Things. Here, we demonstrate a dye-sensitized solar cell (DSC) that achieves very high power-conversion efficiencies (PCEs) under ambient light conditions. Our photosystem combines two judiciously designed sensitizers, coded D35 and XY1, with the copper complex Cu(II/I)(tmby) as a redox shuttle (tmby, 4,4‧,6,6‧-tetramethyl-2,2‧-bipyridine), and features a high open-circuit photovoltage of 1.1 V. The DSC achieves an external quantum efficiency for photocurrent generation that exceeds 90% across the whole visible domain from 400 to 650 nm, and achieves power outputs of 15.6 and 88.5 μW cm-2 at 200 and 1,000 lux, respectively, under illumination from a model Osram 930 warm-white fluorescent light tube. This translates into a PCE of 28.9%.

The effect of regulatory governance on efficiency of thermal power generation in India: A stochastic frontier analysis

International Nuclear Information System (INIS)

Ghosh, Ranjan; Kathuria, Vinish

2016-01-01

This paper investigates the impact of institutional quality – typified as regulatory governance – on the performance of thermal power plants in India. The Indian power sector was reformed in the early 1990s. However, reforms are effective only as much as the regulators are committed in ensuring that they are implemented. We hypothesize that higher the quality of regulation in a federal Indian state, higher is the efficiency of electric generation utilities. A translog stochastic frontier model is estimated using index of state-level independent regulation as one of the determinants of inefficiency. The dataset comprises a panel of 77 coal-based thermal power plants during the reform period covering over 70% of installed electricity generation capacity. The mean technical efficiency of 76.7% indicates there is wide scope for efficiency improvement in the sector. Results are robust to various model specifications and show that state-level regulators have positively impacted plant performance. Technical efficiency is sensitive to both unbundling of state utilities, and regulatory experience. The policy implication is that further reforms which empower independent regulators will have far reaching impacts on power sector performance. - Highlights: • The impact of regulatory governance on Indian generation efficiency is investigated. • Stochastic frontier analysis (SFA) on a panel dataset covering pre and post reform era. • Index of state-wise variation in regulation to explain inefficiency effects. • Results show improved but not very high technical efficiencies. • State-level regulation has positively impacted power plant performance.

Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients

NARCIS (Netherlands)

Yip, N.Y.; Vermaas, D.A.; Nijmeijer, K.; Elimelech, M.

2014-01-01

Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we

Exponential current pulse generation for efficient very high-impedance multisite stimulation.

Science.gov (United States)

Ethier, S; Sawan, M

2011-02-01

We describe in this paper an intracortical current-pulse generator for high-impedance microstimulation. This dual-chip system features a stimuli generator and a high-voltage electrode driver. The stimuli generator produces flexible rising exponential pulses in addition to standard rectangular stimuli. This novel stimulation waveform is expected to provide superior energy efficiency for action potential triggering while releasing less toxic reduced ions in the cortical tissues. The proposed fully integrated electrode driver is used as the output stage where high-voltage supplies are generated on-chip to significantly increase the voltage compliance for stimulation through high-impedance electrode-tissue interfaces. The stimuli generator has been implemented in 0.18-μm CMOS technology while a 0.8-μm CMOS/DMOS process has been used to integrate the high-voltage output stage. Experimental results show that the rectangular pulses cover a range of 1.6 to 167.2 μA with a DNL and an INL of 0.098 and 0.163 least-significant bit, respectively. The maximal dynamic range of the generated exponential reaches 34.36 dB at full scale within an error of ± 0.5 dB while all of its parameters (amplitude, duration, and time constant) are independently programmable over wide ranges. This chip consumes a maximum of 88.3 μ W in the exponential mode. High-voltage supplies of 8.95 and -8.46 V are generated by the output stage, boosting the voltage swing up to 13.6 V for a load as high as 100 kΩ.

A New Chaos-Based Color Image Encryption Scheme with an Efficient Substitution Keystream Generation Strategy

Directory of Open Access Journals (Sweden)

Chong Fu

2018-01-01

Full Text Available This paper suggests a new chaos-based color image cipher with an efficient substitution keystream generation strategy. The hyperchaotic Lü system and logistic map are employed to generate the permutation and substitution keystream sequences for image data scrambling and mixing. In the permutation stage, the positions of colored subpixels in the input image are scrambled using a pixel-swapping mechanism, which avoids two main problems encountered when using the discretized version of area-preserving chaotic maps. In the substitution stage, we introduce an efficient keystream generation method that can extract three keystream elements from the current state of the iterative logistic map. Compared with conventional method, the total number of iterations is reduced by 3 times. To ensure the robustness of the proposed scheme against chosen-plaintext attack, the current state of the logistic map is perturbed during each iteration and the disturbance value is determined by plain-pixel values. The mechanism of associating the keystream sequence with plain-image also helps accelerate the diffusion process and increase the degree of randomness of the keystream sequence. Experimental results demonstrate that the proposed scheme has a satisfactory level of security and outperforms the conventional schemes in terms of computational efficiency.

Generation of Functional Cardiomyocytes from Efficiently Generated Human iPSCs and a Novel Method of Measuring Contractility.

Directory of Open Access Journals (Sweden)

Sheeja Rajasingh

Full Text Available Human induced pluripotent stem cells (iPSCs derived cardiomyocytes (iCMCs would provide an unlimited cell source for regenerative medicine and drug discoveries. The objective of our study is to generate functional cardiomyocytes from human iPSCs and to develop a novel method of measuring contractility of CMCs. In a series of experiments, adult human skin fibroblasts (HSF and human umbilical vein endothelial cells (HUVECs were treated with a combination of pluripotent gene DNA and mRNA under specific conditions. The iPSC colonies were identified and differentiated into various cell lineages, including CMCs. The contractile activity of CMCs was measured by a novel method of frame-by-frame cross correlation (particle image velocimetry-PIV analysis. Our treatment regimen transformed 4% of HSFs into iPSC colonies at passage 0, a significantly improved efficiency compared with use of either DNA or mRNA alone. The iPSCs were capable of differentiating both in vitro and in vivo into endodermal, ectodermal and mesodermal cells, including CMCs with >88% of cells being positive for troponin T (CTT and Gata4 by flow cytometry. We report a highly efficient combination of DNA and mRNA to generate iPSCs and functional iCMCs from adult human cells. We also report a novel approach to measure contractility of iCMCs.

Generation of Functional Cardiomyocytes from Efficiently Generated Human iPSCs and a Novel Method of Measuring Contractility.

Science.gov (United States)

Rajasingh, Sheeja; Thangavel, Jayakumar; Czirok, Andras; Samanta, Saheli; Roby, Katherine F; Dawn, Buddhadeb; Rajasingh, Johnson

2015-01-01

Human induced pluripotent stem cells (iPSCs) derived cardiomyocytes (iCMCs) would provide an unlimited cell source for regenerative medicine and drug discoveries. The objective of our study is to generate functional cardiomyocytes from human iPSCs and to develop a novel method of measuring contractility of CMCs. In a series of experiments, adult human skin fibroblasts (HSF) and human umbilical vein endothelial cells (HUVECs) were treated with a combination of pluripotent gene DNA and mRNA under specific conditions. The iPSC colonies were identified and differentiated into various cell lineages, including CMCs. The contractile activity of CMCs was measured by a novel method of frame-by-frame cross correlation (particle image velocimetry-PIV) analysis. Our treatment regimen transformed 4% of HSFs into iPSC colonies at passage 0, a significantly improved efficiency compared with use of either DNA or mRNA alone. The iPSCs were capable of differentiating both in vitro and in vivo into endodermal, ectodermal and mesodermal cells, including CMCs with >88% of cells being positive for troponin T (CTT) and Gata4 by flow cytometry. We report a highly efficient combination of DNA and mRNA to generate iPSCs and functional iCMCs from adult human cells. We also report a novel approach to measure contractility of iCMCs.

CdS/TiO2 photoanodes via solution ion transfer method for highly efficient solar hydrogen generation

Science.gov (United States)

Krishna Karuturi, Siva; Yew, Rowena; Reddy Narangari, Parvathala; Wong-Leung, Jennifer; Li, Li; Vora, Kaushal; Tan, Hark Hoe; Jagadish, Chennupati

2018-03-01

Cadmium sulfide (CdS) is a unique semiconducting material for solar hydrogen generation applications with a tunable, narrow bandgap that straddles water redox potentials. However, its potential towards efficient solar hydrogen generation has not yet been realized due to low photon-to-current conversions, high charge carrier recombination and the lack of controlled preparation methods. In this work, we demonstrate a highly efficient CdS/TiO2 heterostructured photoelectrode using atomic layer deposition and solution ion transfer reactions. Enabled by the well-controlled deposition of CdS nanocrystals on TiO2 inverse opal (TiIO) nanostructures using the proposed method, a saturation photocurrent density of 9.1 mA cm-2 is realized which is the highest ever reported for CdS-based photoelectrodes. We further demonstrate that the passivation of a CdS surface with an ultrathin amorphous layer (˜1.5 nm) of TiO2 improves the charge collection efficiency at low applied potentials paving the way for unassisted solar hydrogen generation.

Facilitating efficient augmentation of transmission networks to connect renewable energy generation: the Australian experience

International Nuclear Information System (INIS)

Wright, Glen

2012-01-01

Australia is heavily dependent on coal for electricity generation. The Renewable Energy Target has spurred growth in the utilization of renewable energy sources, with further growth expected into the future. Australia's strongest renewable energy sources are generally distant from the transmission network in resource ‘basins’. Investment is needed to augment the transmission network to enable delivery of electricity from these sources to consumers. Considerable economies of scale flow from anticipating the connection of numerous generators in an area over time and sizing augmentations accordingly. Following a lengthy rulemaking process, the National Electricity Rules were recently amended by a new rule, designed to facilitate the construction of such efficiently sized augmentations. However, the new rule is more conservative than initially envisaged, making little substantive change to the current frameworks for augmentation and connection. This paper outlines these frameworks and the rulemaking process and identifies the key debates surrounding the rule change are identified. This paper then provides a detailed analysis of the new rule, concluding that it is defective in a number of respects and is unlikely to result in the efficient and timely augmentation of the network needed to unlock the potential of Australia's strongest renewable energy resources. - Highlights: ► Remoteness of renewable energy sources is a barrier to greater renewable energy utilization. ► Significant economies of scale flow from efficiently-sized transmission network augmentation. ► Current frameworks in Australia do not incentivise efficiently-sized network augmentations. ► The lack of property rights in an augmentation is particularly problematic. ► The new Scale Efficient Network Extensions rule is not apt to facilitate efficiently-sized network augmentations.

Efficient implementation of Bailey and Borwein pseudo-random number generator based on normal numbers

Science.gov (United States)

Beliakov, G.; Creighton, D.; Johnstone, M.; Wilkin, T.

2013-08-01

This paper describes an implementation of a Linear Congruential Generator (LCG) based on the binary representation of the normal number α, and of a combined generator based on that LCG. The base LCG with the modulus 333 provides a quality sequence with the period ≈3.7ṡ1015, which passes all but two statistical tests from BigCrush test suite. We improved on the original implementation by adapting Barrett's modular reduction method, which resulted in four-fold increase in efficiency. The combined generator has the period of ≈1023 and passes all tests from BigCrush suite.

Market (in)efficiency in valuing electric utilities-The case of Norwegian generating companies

International Nuclear Information System (INIS)

Kjaerland, Frode

2010-01-01

After deregulation of the energy market in Norway, a number of mergers and acquisitions of hydropower generating companies have taken place. However, valuation of these companies has proved controversial. From an ex-post perspective, there is support for the criticism that generation assets have been sold too cheaply. This article presents a simple valuation model providing evidence of how value has evolved. On the basis of these results, we discuss the valuation from an ex ante perspective and in the light of the market efficiency hypothesis of (Fama, 1970) and (Fama, 1991).

Efficient generation of image chips for training deep learning algorithms

Science.gov (United States)

Han, Sanghui; Fafard, Alex; Kerekes, John; Gartley, Michael; Ientilucci, Emmett; Savakis, Andreas; Law, Charles; Parhan, Jason; Turek, Matt; Fieldhouse, Keith; Rovito, Todd

2017-05-01

Training deep convolutional networks for satellite or aerial image analysis often requires a large amount of training data. For a more robust algorithm, training data need to have variations not only in the background and target, but also radiometric variations in the image such as shadowing, illumination changes, atmospheric conditions, and imaging platforms with different collection geometry. Data augmentation is a commonly used approach to generating additional training data. However, this approach is often insufficient in accounting for real world changes in lighting, location or viewpoint outside of the collection geometry. Alternatively, image simulation can be an efficient way to augment training data that incorporates all these variations, such as changing backgrounds, that may be encountered in real data. The Digital Imaging and Remote Sensing Image Image Generation (DIRSIG) model is a tool that produces synthetic imagery using a suite of physics-based radiation propagation modules. DIRSIG can simulate images taken from different sensors with variation in collection geometry, spectral response, solar elevation and angle, atmospheric models, target, and background. Simulation of Urban Mobility (SUMO) is a multi-modal traffic simulation tool that explicitly models vehicles that move through a given road network. The output of the SUMO model was incorporated into DIRSIG to generate scenes with moving vehicles. The same approach was used when using helicopters as targets, but with slight modifications. Using the combination of DIRSIG and SUMO, we quickly generated many small images, with the target at the center with different backgrounds. The simulations generated images with vehicles and helicopters as targets, and corresponding images without targets. Using parallel computing, 120,000 training images were generated in about an hour. Some preliminary results show an improvement in the deep learning algorithm when real image training data are augmented with

Algoritmo con mínimo almacenamiento de memoria para el cálculo de caída de tensión en redes de distribución

OpenAIRE

Sánchez Miño, Santiago; Ruiz Ruiz, Raúl A.

1987-01-01

El presente trabajo describe algunas técnicas de mínimo almacenamiento de matrices porosas. Se hace un análisis de las ventajas de uno de estos algoritmos sobre los métodos tradicionales que utilizan técnicas matriciales para resolver las redes de sistemas de energía eléctrica. Finalmente, se describe los programas de computación para aplicar el método de mínimo almacenamiento en el cálculo de la caída de tensión en redes de distribución.

El algoritmo de la transferencia como antecesor del discurso del amo. // The algorithm of transference as a predecessor of the master`s discourse.

Directory of Open Access Journals (Sweden)

Alexander Cruz Aponasenko.

2010-06-01

Full Text Available This work establishes the counter argument between Lacan’s elaboration discussed in the Proposition of October 9 on the Psychoanalyst of the School, regarding the transference, and the quadripode called “master’s discourse”, delivered in the 1969-1970 seminar. In the “Proposition”, Lacan shows a formula commonly known as “algorithm of transference”, which formalizes the opening to the unconscious through the transference signifier operation and allows the possibility of the analytical work by the installation of the subject-supposed-to-know. We will see how this algorithm precedes the master’s discourse or the discourse of the unconscious. Thus we are going to establish a directionality in the analytical cure by observing the reversal of the master’s discourse that is the discourse of the analyst. // El trabajo establece un contrapunto entre la elaboración de Lacan presentada en la proposición del 9 de octubre sobre el psicoanalista de la escuela, en relación a la transferencia, y el cuadrípodo denominado "discurso del amo", presentado en el seminario del año 1969-1970. En la “proposición” Lacan presenta una fórmula conocida coloquialmente como "algoritmo de la transferencia", que permite formalizar la apertura al inconsciente mediante la operación del significante de la transferencia y producir allí la posibilidad del trabajo analítico vía la instalación del sujeto supuesto saber. Veremos cómo este algoritmo antecede al discurso del amo o discurso del inconsciente. Esto nos permitirá establecer una direccionalidad en la cura analítica observando la inversión del discurso del amo que es el discurso del analista.

Predicción de la generación interna volumétrica de calor y la capacidad calorífica durante un tratamiento electromagnético del material usando algoritmos híbridos

Directory of Open Access Journals (Sweden)

Edgar García-Morantes

2018-01-01

Full Text Available Este trabajo considera la estimación de la generación interna volumétrica de calor y la capacidad calorífica de una muestra esférica sólida calentada por un campo electromagnético homogéneo variante en el tiempo. Para tal fin, la estrategia numérica soluciona el correspondiente problema inverso. Tres formas funcionales (lineal, senoidal y exponencial para el campo electromagnético fueron considerados. Ruido blanco fue agregado al perfil de temperatura teórica (i.e. la solución del problema directo para simular una situación más realística. La temperatura se pretendió que fuera leída por cuatro sensores. El problema inverso fue solucionado a través de tres diferentes enfoques: usando un optimizador tradicional, usando técnicas modernas y usando una mezcla de ambos. En el primer caso, usamos un algoritmo determinístico tradicional como lo es el de Levenberg-Marquardt (LM. En el segundo, consideramos tres metaheurísticos estocásticos: El Algoritmo de optimización de la espiral (SOA, la Búsqueda en vórtice (VS, y el método de atracción ponderada (WAM. Para el caso final, proponemos híbridos entre el LM y los algoritmos metahehurísticos. Los resultados muestran que LM converge a la solución esperada solo si las condiciones iniciales (IC están dentro de un rango limitado. Por otra parte, los metaheurísticos convergen en un amplio rango de IC pero muestra baja precisión. Los enfoques híbridos convergen y mejoran la precisión obtenida con los metaheurísticos. La diferencia entre los valores esperados y obtenidos, así como, los errores RMS son reportados y comparados para los tres métodos.

Efficient error correction for next-generation sequencing of viral amplicons.

Science.gov (United States)

Skums, Pavel; Dimitrova, Zoya; Campo, David S; Vaughan, Gilberto; Rossi, Livia; Forbi, Joseph C; Yokosawa, Jonny; Zelikovsky, Alex; Khudyakov, Yury

2012-06-25

Next-generation sequencing allows the analysis of an unprecedented number of viral sequence variants from infected patients, presenting a novel opportunity for understanding virus evolution, drug resistance and immune escape. However, sequencing in bulk is error prone. Thus, the generated data require error identification and correction. Most error-correction methods to date are not optimized for amplicon analysis and assume that the error rate is randomly distributed. Recent quality assessment of amplicon sequences obtained using 454-sequencing showed that the error rate is strongly linked to the presence and size of homopolymers, position in the sequence and length of the amplicon. All these parameters are strongly sequence specific and should be incorporated into the calibration of error-correction algorithms designed for amplicon sequencing. In this paper, we present two new efficient error correction algorithms optimized for viral amplicons: (i) k-mer-based error correction (KEC) and (ii) empirical frequency threshold (ET). Both were compared to a previously published clustering algorithm (SHORAH), in order to evaluate their relative performance on 24 experimental datasets obtained by 454-sequencing of amplicons with known sequences. All three algorithms show similar accuracy in finding true haplotypes. However, KEC and ET were significantly more efficient than SHORAH in removing false haplotypes and estimating the frequency of true ones. Both algorithms, KEC and ET, are highly suitable for rapid recovery of error-free haplotypes obtained by 454-sequencing of amplicons from heterogeneous viruses.The implementations of the algorithms and data sets used for their testing are available at: http://alan.cs.gsu.edu/NGS/?q=content/pyrosequencing-error-correction-algorithm.

Polarization holograms allow highly efficient generation of complex light beams.

Science.gov (United States)

Ruiz, U; Pagliusi, P; Provenzano, C; Volke-Sepúlveda, K; Cipparrone, Gabriella

2013-03-25

We report a viable method to generate complex beams, such as the non-diffracting Bessel and Weber beams, which relies on the encoding of amplitude information, in addition to phase and polarization, using polarization holography. The holograms are recorded in polarization sensitive films by the interference of a reference plane wave with a tailored complex beam, having orthogonal circular polarizations. The high efficiency, the intrinsic achromaticity and the simplicity of use of the polarization holograms make them competitive with respect to existing methods and attractive for several applications. Theoretical analysis, based on the Jones formalism, and experimental results are shown.

Un algoritmo genético para el problema de Job Shop Flexible A genetic algorithm for the Flexible Job Shop problem

Directory of Open Access Journals (Sweden)

Rosa Medina Durán

2011-06-01

Full Text Available En este estudio se propone e implementa computacionalmente un algoritmo genético secuencial para resolver el problema del Job Shop Flexible (existente en la Gestión de Operaciones, el cual es parte de la familia de los problemas de programación de tareas o trabajos (Scheduling en un taller que funciona a pedido. Surge como una generalización del problema del Job Shop y permite optimizar el uso de los recursos (máquinas con mayor flexibilidad, ya que cada máquina puede realizar más de una operación. Este problema ha sido estudiado por numerosos autores, los que han propuesto diversos modelos matemáticos y enfoques heurísticos. Debido a la naturaleza combinatoria, los métodos exactos que resuelven modelos matemáticos encuentran soluciones sólo para instancias pequeñas o simples del problema mencionado. Los resultados muestran la efectividad del algoritmo propuesto para entregar buenas soluciones en tiempos computacionales razonables en más de 130 instancias encontradas en la literatura.This study proposes and computationally implements a sequential genetic algorithm to solve the Flexible Job Shop problem (found in Operations Management, which is part of the family of job or task scheduling problems in a shop that works on demand. It is a generalization of the Job Shop problem, and allows optimizing the use of resources (machines in the shop, with greater flexibility, since each machine can perform more than one operation. This problem has been studied by many authors, who have proposed various mathematical models and heuristic approaches. Due to the combinatorial nature of the problem, the exact methods that solve the mathematical models are often solutions for small and simple instances of the problem. The results show the effectiveness of the proposed algorithm to provide good solutions in reasonable computational times in over 130 instances found in the literatura.

High-Efficiency, Multijunction Solar Cells for Large-Scale Solar Electricity Generation

Science.gov (United States)

Kurtz, Sarah

2006-03-01

A solar cell with an infinite number of materials (matched to the solar spectrum) has a theoretical efficiency limit of 68%. If sunlight is concentrated, this limit increases to about 87%. These theoretical limits are calculated using basic physics and are independent of the details of the materials. In practice, the challenge of achieving high efficiency depends on identifying materials that can effectively use the solar spectrum. Impressive progress has been made with the current efficiency record being 39%. Today's solar market is also showing impressive progress, but is still hindered by high prices. One strategy for reducing cost is to use lenses or mirrors to focus the light on small solar cells. In this case, the system cost is dominated by the cost of the relatively inexpensive optics. The value of the optics increases with the efficiency of the solar cell. Thus, a concentrator system made with 35%- 40%-efficient solar cells is expected to deliver 50% more power at a similar cost when compare with a system using 25%-efficient cells. Today's markets are showing an opportunity for large concentrator systems that didn't exist 5-10 years ago. Efficiencies may soon pass 40% and ultimately may reach 50%, providing a pathway to improved performance and decreased cost. Many companies are currently investigating this technology for large-scale electricity generation. The presentation will cover the basic physics and more practical considerations to achieving high efficiency as well as describing the current status of the concentrator industry. This work has been authored by an employee of the Midwest Research Institute under Contract No. DE- AC36-99GO10337 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work, or allow

¿Es la ciudad de México policéntrica? Nuevos datos y algoritmos para la detección de centralidades urbanas

Directory of Open Access Journals (Sweden)

Jorge Alberto Montejano-Escamilla

2015-01-01

Full Text Available Con la emergencia de nuevos algoritmos para el análisis de redes y la aparición de bases de datos económicas desagregadas a nivel de unidad, se plantea un método distinto a los anteriormente reportados en la literatura especializada para detectar centralidades urbanas. La primera parte define la centralidad urbana y presenta una disertación teórica sobre la condición policéntrica. Posteriormente, se muestran los métodos anteriormente usados para la medición de las centralidades y se describen las nuevas herramientas empleadas en esta investigación. Finalmente, se presentan algunos resultados de este método aplicado como caso de estudio en la ciudad de México.

Comparación de algoritmos numéricos en problemas de lubricación hidrodinámica con cavitación en dimensión uno

OpenAIRE

Durany, José; Calvo, N.; Vázquez Hurtado, Carlos

2009-01-01

En este trabajo se analizan algunos algoritmos numéricos para problemas matem,áticos unidimensionales de frontera libre que aparecen en la lubricación hidrodinámica de dispositivos eje-cojinete. Los modelos matemáticos de estos problemas de la mecánica de fluidos en capas delgadas se basan en la ecuación de Reynolds, acompañada de ciertas condiciones que tienen en cuenta los fenómenos de cavitación. En este sentido, se compara el modelo de cavitación de Elrod-Adams y el modelo de cavitación d...

Estudio comparativo sobre la aplicación de los algoritmos PSO y SQP en la optimización de pórticos planos de concreto armado

OpenAIRE

Lapadula Sequera, Víctor Antonio

2014-01-01

Esta investigación presenta la comparación de las técnicas SQP (Sequential Cuadratic Programming) y PSO (Particle Swarm optimization) al ser aplicadas al problema de optimización de pórticos planos de concreto armado. El SQP y el PSO son algoritmos de optimización provenientes de filosofías diferentes. El primero es una técnica clásica basada en cálculo diferencial, mientras que el segundo es una meta-heurística inspirada en comportamientos observados en la naturaleza. Como función objetivo d...

Efficient Pruning Method for Ensemble Self-Generating Neural Networks

Directory of Open Access Journals (Sweden)

Hirotaka Inoue

2003-12-01

Full Text Available Recently, multiple classifier systems (MCS have been used for practical applications to improve classification accuracy. Self-generating neural networks (SGNN are one of the suitable base-classifiers for MCS because of their simple setting and fast learning. However, the computation cost of the MCS increases in proportion to the number of SGNN. In this paper, we propose an efficient pruning method for the structure of the SGNN in the MCS. We compare the pruned MCS with two sampling methods. Experiments have been conducted to compare the pruned MCS with an unpruned MCS, the MCS based on C4.5, and k-nearest neighbor method. The results show that the pruned MCS can improve its classification accuracy as well as reducing the computation cost.

Efficient 1.9-μm Raman generation in a hydrogen-filled hollow-core fibre

Energy Technology Data Exchange (ETDEWEB)

Gladyshev, A V; Kolyadin, A N; Kosolapov, A F; Yatsenko, Yu P; Pryamikov, A D; Biryukov, A S; Bufetov, I A; Dianov, E M [Fiber Optics Research Center, Russian Academy of Sciences, Moscow (Russian Federation)

2015-09-30

Efficient Raman generation in a molecular hydrogenfilled hollow-core fibre having a cladding in the form of a single ring of capillaries has been demonstrated for the first time. The pump source used was a Q-switched Nd:YAG laser with a pulse duration of 125 ns, and a single-pass (cavity-free) configuration was employed. The maximum average output power at 1.9 μm was 300 mW, and the differential quantum efficiency was 87%, a record level for such experiments. (lasers)

A compact, high efficiency contra-rotating generator suitable for wind turbines in the urban environment

Energy Technology Data Exchange (ETDEWEB)

Booker, J.D. [Department of Mechanical Engineering, University of Bristol, University Walk, Bristol BS8 1TR (United Kingdom); Mellor, P.H.; Wrobel, R.; Drury, D. [Department of Electrical and Electronic Engineering, University of Bristol, Bristol (United Kingdom)

2010-09-15

This paper is concerned with the design, development and performance testing of a permanent magnet (PM) generator for wind turbine applications in urban areas. The radially interacting armature windings and magnet array are carried on direct drive, contra-rotating rotors, resulting in a high torque density and efficiency. This topology also provides improved physical and mechanical characteristics such as compactness, low starting torque, elimination of gearboxes, low maintenance, low noise and vibration, and the potential for modular construction. The design brief required a 50 kW continuous rated prototype generator, with a relative speed at the air-gap of 500 rpm. A test rig has been instrumented to give measurements of the mechanical input (torque and speed) and electrical output (voltage, current and power) of the generator, as well as temperature readings from inside the generator using a wireless telemetry device. Peak power output was found to be 48 kW at a contra-rotating speed of 500 rpm, close to the design target, with an efficiency of 94%. It is anticipated that the generator will find application in a wide range of wind turbine designs suited to the urban environment, e.g. types sited on the top of buildings, as there is growing interest in providing quiet, low cost, clean electricity at point of use. (author)

Un Algoritmo de Estimación de Distribuciones copulado con la Distribución Generalizada de Mallows para el Problema de Ruteo de Autobuses Escolares con Selección de Paradas

Directory of Open Access Journals (Sweden)

Ricardo Pérez-Rodríguez

2017-07-01

Full Text Available Resumen: Aunque los algoritmos de estimación de distribuciones fueron originalmente diseñados para resolver problemas con dominio de valores reales o enteros, en esta contribución se utilizan para la resolución de un problema basado en permutaciones. El ruteo de autobuses escolares con selección de paradas es resuelto utilizando la distribución generalizada de Mallows como un intento para describir y obtener una distribución de probabilidad explicita sobre un conjunto de rutas de autobuses escolares. Además, un operador de mutación es considerado para mejorar la estimación de la permutación central, un parámetro de la distribución de Mallows. Diferentes y diversas instancias sirvieron como parámetro de entrada y prueba para mostrar que problemas basados en permutaciones tales como el ruteo de autobuses escolares con selección de paradas pueden ser resueltos por medio de un modelo de probabilidad, y mejorar la estimación de la permutación central ayuda al desempeño del algoritmo. Abstract: Although the estimation of distribution algorithms were originally designed for solving integer or real-valued domains, this contribution applies the algorithms mentioned to deal with a permutation-based problem, called school bus routing problem with bus stop selection, using the generalized Mallows distribution as an attempt to describe and obtain an explicit probability distribution over a set of school bus routes. In addition, a mutation operator is considered for improving the estimation of the central permutation, a parameter of the Mallows distribution. Different and diverse instances served as input and test parameters in order to show that permutation-based optimization problems such as the school bus routing problem with bus stop selection can be solved by means of a probability model, and improving the estimation of the central permutation helps the performance of the algorithm. Palabras clave: Algoritmo de estimación de

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

The generation of efficient supported (Heterogeneous) olefin metathesis catalysts

Energy Technology Data Exchange (ETDEWEB)

Grubbs, Robert H

2013-04-05

Over the past decade, a new family of homogeneous metathesis catalysts has been developed that will tolerate most organic functionalities as well as water and air. These homogeneous catalysts are finding numerous applications in the pharmaceutical industry as well as in the production of functional polymers. In addition the catalysts are being used to convert seed oils into products that can substitute for those that are now made from petroleum products. Seed oils are unsaturated, contain double bonds, and are a ready source of linear hydrocarbon fragments that are specifically functionalized. To increase the number of applications in the area of biomaterial conversion to petrol chemicals, the activity and efficiency of the catalysts need to be as high as possible. The higher the efficiency of the catalysts, the lower the cost of the conversion and a larger number of practical applications become available. Active supported catalysts were prepared and tested in the conversion of seed oils and other important starting materials. The outcome of the work was successful and the technology has been transferred to a commercial operation to develop viable applications of the discovered systems. A biorefinery that converts seed oils is under construction in Indonesia. The catalysts developed in this study will be considered for the next generation of operations.

Highly efficient hybrid energy generator: coupled organic photovoltaic device and randomly oriented electrospun poly(vinylidene fluoride) nanofiber.

Science.gov (United States)

Park, Boongik; Lee, Kihwan; Park, Jongjin; Kim, Jongmin; Kim, Ohyun

2013-03-01

A hybrid architecture consisting of an inverted organic photovoltaic device and a randomly-oriented electrospun PVDF piezoelectric device was fabricated as a highly-efficient energy generator. It uses the inverted photovoltaic device with coupled electrospun PVDF nanofibers as tandem structure to convert solar and mechanical vibrations energy to electricity simultaneously or individually. The power conversion efficiency of the photovoltaic device was also significantly improved up to 4.72% by optimized processes such as intrinsic ZnO, MoO3 and active layer. A simple electrospinning method with the two electrode technique was adopted to achieve a high voltage of - 300 mV in PVDF piezoelectric fibers. Highly-efficient HEG using voltage adder circuit provides the conceptual possibility of realizing multi-functional energy generator whenever and wherever various energy sources are available.

Design of Algorithms for their Use in the Control of Solutes Transport in Contaminated Aquifers; Diseno de algoritmos para su uso en el control del transporte de solutos en acuiferos contaminados

Energy Technology Data Exchange (ETDEWEB)

Martinez Najera, Juan Diego [Comision Federal de Electricidad (Mexico)

2002-06-01

This paper establishes the theoretical foundations of a mathematical methodology to approach the rehabilitation of aquifers contaminated by dissolved substances, with the assistance of numerical techniques. The derived algorithms are of control or management type, since simultaneously to the predictive numerical solution of the solute transport equation, they determine those solutions that fulfil water quality restrictions. The controlling variable is the concentration of the polluting agent dissolved in the flow field. The considerations are kinematics because they take into account the advection and dispersion terms, but they also considerate the first order kinetic sorption model and the sources/sinks for the concentration. We describe the physical arguments and mathematical theory of subdiferentials necessary to establish the control problem of initial and boundary values for the solutes transport equation; afterwards, the primal variational model and the mixed of dual internal control as well as the formal discrete version of both formulations are obtained, so that solution algorithms of finite element semi discrete type are generated. Due to the hyperbolic-parabolic character of the transport equation, when the advective tem is dominant, in this work it is approximated by means of the lkeda's partial upwind technique. To prove the theory a hypothetical example is presented, and we analyze the two possible cases for the concentration of a polluting agent: when it dose not exceed and when it escapes the regulator limits of water quality. In both situations the primal and mixed algorithms determine the appropriate numerical solutions of each kind of problem. [Spanish] Este trabajo establece los fundamentos teoricos de una metodologia matematica para abordar la rehabilitacion de mantos acuiferos contaminados por sustancias disueltas, con la asistencia de tecnicas numericas. Los algoritmos que se derivan son de control o de manejo, ya que inmerso a la

Spectral distribution of the efficiency of terahertz difference frequency generation upon collinear propagation of interacting waves in semiconductor crystals

International Nuclear Information System (INIS)

Orlov, Sergei N; Polivanov, Yurii N

2007-01-01

Dispersion phase matching curves and spectral distributions of the efficiency of difference frequency generation in the terahertz range are calculated for collinear propagation of interacting waves in zinc blende semiconductor crystals (ZnTe, CdTe, GaP, GaAs). The effect of the pump wavelength, the nonlinear crystal length and absorption in the terahertz range on the spectral distribution of the efficiency of difference frequency generation is analysed. (nonlinear optical phenomena)

Generating efficiency: The power of price caps in the public and private Spanish electricity sectors

International Nuclear Information System (INIS)

Arocena, P.; Price, C.W.

1999-01-01

Economic regulation of firms with market power has placed increasing emphasis on incentive-based regulation such as price caps. The move to such regulation often coincides with a change of ownership, making it difficult to separate the incentive effects. We focus on the effect of regulation alone by analysing the imposition of price cap type regulation on both publicly and privately owned Spanish electricity generators in 1988, several years before three was any change of ownership. Our initial results indicate that the publicly owned generators are generally more efficient than the private ones, but that the effect of price caps is to increase the efficiency of private sector plants faster than those in the public sector. We introduce two novelties into the analysis: we incorporate levels of CO2 and NOx emissions; and we include declared plant availability as an output. The outcome is dependent on the choice of inputs and outputs, and we argue that our measures are more appropriate than traditional measures for a system of central despatch for generators facing environmental constraints. (au) 37 refs

Efficient generation of knock-in transgenic zebrafish carrying reporter/driver genes by CRISPR/Cas9-mediated genome engineering.

Science.gov (United States)

Kimura, Yukiko; Hisano, Yu; Kawahara, Atsuo; Higashijima, Shin-ichi

2014-10-08

The type II bacterial CRISPR/Cas9 system is rapidly becoming popular for genome-engineering due to its simplicity, flexibility, and high efficiency. Recently, targeted knock-in of a long DNA fragment via homology-independent DNA repair has been achieved in zebrafish using CRISPR/Cas9 system. This raised the possibility that knock-in transgenic zebrafish could be efficiently generated using CRISPR/Cas9. However, how widely this method can be applied for the targeting integration of foreign genes into endogenous genomic loci is unclear. Here, we report efficient generation of knock-in transgenic zebrafish that have cell-type specific Gal4 or reporter gene expression. A donor plasmid containing a heat-shock promoter was co-injected with a short guide RNA (sgRNA) targeted for genome digestion, a sgRNA targeted for donor plasmid digestion, and Cas9 mRNA. We have succeeded in establishing stable knock-in transgenic fish with several different constructs for 4 genetic loci at a frequency being exceeding 25%. Due to its simplicity, design flexibility, and high efficiency, we propose that CRISPR/Cas9-mediated knock-in will become a standard method for the generation transgenic zebrafish.

Automotive Thermoelectric Generator impact on the efficiency of a drive system with a combustion engine

Directory of Open Access Journals (Sweden)

Ziolkowski Andrzej

2017-01-01

Full Text Available Increasing the combustion engine drive systems efficiency is currently being achieved by structural changes in internal combustion engines and its equipment, which are geared towards limiting mechanical, thermal and outlet losses. For this reason, downsizing. In addition to these changes, all manner of exhaust gas energy recovery systems are being investigated and implemented, including turbocompound, turbogenerators and thermoelectric generators. The article presents the author’s idea of a thermoelectric generator system of automotive applications ATEG (Automotive Thermoelectric Generator and the study of the recovery of exhaust gas energy stream. The ATEG consists of a heat exchanger, thermoelectric modules and a cooling system. In this solution, 24 commercial thermoelectric modules based on Bi2Te3 (bismuth telluride were used. Measurements were made at two engine test sites on which SI and CI engines were installed. The exhaust gas parameters (temperature and mass flow rate, fuel consumption and operating parameters of the ATEG – the intensity and the voltage generated by the thermoelectric modules and the temperature on the walls of the heat exchanger – were all measured in the experiments. Based on the obtained results, the exhaust gas energy flow and the power of the ATEG were determined as well as its effect on the diesel engine drive system efficiency.

Algoritmo para geolocalización de dispositivos móviles a partir de emisores de WIFI

Directory of Open Access Journals (Sweden)

María Portillo Montiel

2015-04-01

Full Text Available Esta investigación propone un método para la geolocalización de dispositivos móviles a partir de señales WiFi predeterminadas, prescindiendo del uso del GPS para evitar potenciales problemas de seguridad y malware. El método propuesto, se basa en la técnica conocida como Punto de Triangulación Aproximado (APIT y parte de una discretización del espacio de acción a partir de un conjunto base de emisores de señal WiFi de coordenadas y radios de acción máximos conocidos, para luego construir una rejilla que incluye las zonas de acción conjunta de todos los emisores al momento de activar la aplicación, es posible estimar con gran precisión la ubicación del dispositivo móvil determinando el área de intersección de las señales visibles en el momento. La implementación del algoritmo propuesto exhibe una complejidad temporal cuadrática respecto al tamaño de la rejilla y lineal sobre la cantidad de emisores iniciales.

Fast Generation of Near-Optimal Plans for Eco-Efficient Stowage of Large Container Vessels

DEFF Research Database (Denmark)

Pacino, Dario; Delgado, Alberto; Jensen, Rune Møller

2011-01-01

Eco-efficient stowage plans that are both competitive and sustainable have become a priority for the shipping industry. Stowage planning is NP-hard and is a challenging optimization problem in practice. We propose a new 2-phase approach that generates near-optimal stowage plans and fulfills indus...

Increased Efficiency of a Permanent Magnet Synchronous Generator through Optimization of NdFeB Magnet Arrays

Science.gov (United States)

Khazdozian, Helena; Hadimani, Ravi; Jiles, David

2014-03-01

The United States is currently dependent on fossil fuels for the majority of its energy needs, which has many negative consequences such as climate change. Wind turbines present a viable alternative, with the highest energy return on investment among even fossil fuel generation. Traditional commercial wind turbines use an induction generator for energy conversion. However, induction generators require a gearbox to increase the rotational speed of the drive shaft. These gearboxes increase the overall cost of the wind turbine and account for about 35 percent of reported wind turbine failures. Direct drive permanent magnet synchronous generators (PMSGs) offer an alternative to induction generators which eliminate the need for a gearbox. Yet, PMSGs can be more expensive than induction generators at large power output due to their size and weight. To increase the efficiency of PMSGs, the geometry and configuration of NdFeB permanent magnets were investigated using finite element techniques. The optimized design of the PMSG increases flux density and minimizes cogging torque with NdFeB permanent magnets of a reduced volume. These factors serve to increase the efficiency and reduce the overall cost of the PMSG. This work is supported by a National Science Foundation IGERT fellowship and the Barbara and James Palmer Endowment at the Department of Electrical and Computer Engineering of Iowa State University.

High-efficiency dual-modes vortex beam generator with polarization-dependent transmission and reflection properties.

Science.gov (United States)

Tang, Shiwei; Cai, Tong; Wang, Guang-Ming; Liang, Jian-Gang; Li, Xike; Yu, Jiancheng

2018-04-23

Vortex beam is believed to be an effective way to extend communication capacity, but available efforts suffer from the issues of complex configurations, fixed operation mode as well as low efficiency. Here, we propose a general strategy to design dual-modes vortex beam generator by using metasurfaces with polarization-dependent transmission and reflection properties. Combining the focusing and vortex functionalities, we design/fabricate a type of compact dual-modes vortex beam generator operating at both reflection/transmission sides of the system. Experimental results demonstrate that the designed metadevice can switch freely and independently between the reflective vortex with topological charge m 1  = 2 and transmissive vortex with m 2  = 1. Moreover, the metadevice exhibits very high efficiencies of 91% and 85% for the reflective and transmissive case respectively. Our findings open a door for multifunctional metadevices with high performances, which indicate wide applications in modern integration-optics and wireless communication systems.

Efficiency analysis of hydroelectric generating plants: A case study for Portugal

International Nuclear Information System (INIS)

Barros, Carlos Pestana

2008-01-01

This paper estimates changes in total productivity, breaking this down into technically efficient change and technological change, by means of data envelopment analysis (DEA) applied to the hydroelectric energy generating plants of EDP - the Portugal Electricity Company. The aim of this procedure is to seek out those best practices that will lead to improved performance in the energy market. We rank the plants according to their change in total productivity for the period 2001-2004, concluding that some plants experienced productivity growth while others experienced a decrease in productivity. The implications arising from the study are that EDP should adopt an internal benchmark management procedure in order to evaluate the relative position of each hydroelectric generating plant and to adopt managerial strategies designed to catch up with the frontier of 'best practices'. As the frontier is shifting along the time, constant efforts are needed in this respect along the time. (author)

Experimental demonstration of efficient and robust second harmonic generation using the adiabatic temperature gradient method

Science.gov (United States)

Dimova, E.; Steflekova, V.; Karatodorov, S.; Kyoseva, E.

2018-03-01

We propose a way of achieving efficient and robust second-harmonic generation. The technique proposed is similar to the adiabatic population transfer in a two-state quantum system with crossing energies. If the phase mismatching changes slowly, e.g., due to a temperature gradient along the crystal, and makes the phase match for second-harmonic generation to occur, then the energy would be converted adiabatically to the second harmonic. As an adiabatic technique, the second-harmonic generation scheme presented is stable to variations in the crystal parameters, as well as in the input light, crystal length, input intensity, wavelength and angle of incidence.

Performance characterization of a power generation unit–organic Rankine cycle system based on the efficiencies of the system components

International Nuclear Information System (INIS)

Knizley, Alta; Mago, Pedro J.; Tobermann, James; Warren, Harrison R.

2015-01-01

Highlights: • Use of waste heat from a power generation unit to generate electricity is explored. • An organic Rankine cycle is used to recover the waste heat. • The system may lower cost, primary energy consumption, and carbon dioxide emission. • A parameter was established to show when the proposed system would provide savings. • The proposed system was evaluated in different locations in the US. - Abstract: This paper analyzes the potential of using the waste heat from a power generation unit to generate additional electricity using an organic Rankine cycle to reduce operational cost, primary energy consumption, and carbon dioxide emissions in different locations in the U.S. The power generation unit–organic Rankine cycle system is compared with a conventional system in terms of operational cost, primary energy consumption, and carbon dioxide emissions reduction. A parameter (R_m_i_n), which is based on system efficiencies, is established to determine when the proposed power generation unit–organic Rankine cycle system would potentially provide savings versus the conventional system in which electricity is purchased from the utility grid. The effect on the R_m_i_n parameter with variation of each system efficiency is also analyzed in this paper. Results indicated that savings in one parameter, such as primary energy consumption, did not imply savings in the other two parameters. Savings in the three parameters (operational cost, primary energy consumption, and carbon dioxide emissions) varied widely based on location due to prices of natural gas and electricity, source-to-site conversion factors, and carbon dioxide emissions conversion factors for electricity and natural gas. Variations in each system efficiency affected R_m_i_n, but varying the power generation unit efficiency had the most dramatic effect in the overall savings potential from the proposed system.

Efficient second harmonic generation by para-nitroaniline embedded in electro-spun polymeric nanofibres

Science.gov (United States)

Gonçalves, Hugo; Saavedra, Inês; Ferreira, Rute AS; Lopes, PE; de Matos Gomes, Etelvina; Belsley, Michael

2018-03-01

Intense well polarized second harmonic light was generated by poly(methyl methacrylate) nanofibres with embedded para-nitroaniline nanocrystals. Subwavelength diameter fibres were electro-spun using a 1:2 weight ratio of chromophore to polymer. Analysis of the generated second harmonic light indicates that the para-nitroaniline molecules, which nominally crystalize in the centrosymmetric space group, were organized into noncentrosymmetric structures leading to a second order susceptibility dominated by a single tensor element. Under the best deposition conditions, the nanofibrers display an effective nonlinear optical susceptibility approximately two orders of magnitude greater than that of potassium dihydrogen phosphate. Generalizing this approach to a broad range of organic molecules with strong individual molecular second order nonlinear responses, but which nominally form centrosymmetric organic crystals, could open a new pathway for the fabrication of efficient sub-micron sized second harmonic light generators.

Detección de obstáculos y espacios transitables en entornos urbanos para sistemas de ayuda a la conducción basados en algoritmos de visión estéreo implementados en GPU

Directory of Open Access Journals (Sweden)

B. Musleh

2012-10-01

Full Text Available Resumen: Tanto los sistemas avanzados de ayuda a la conducción (ADAS aplicados a la mejora de la seguridad vial, como los sistemas de navegación autónoma de vehículos, demandan sensores y algoritmos cada vez más complejos, capaces de obtener e interpretar información del entorno vial. En concreto, las mayores dificultades surgen a la hora de analizar la información proveniente de los entornos urbanos, debido a la diversidad de elementos con distintas características que existen en áreas urbanas. Estos sistemas requieren, cada vez más, que la interpretación de la información se realice en tiempo real para mejorar la toma de decisiones. Por otra parte, la visión estéreo es ampliamente utilizada en sistemas de modelado, dada la gran cantidad de información que proporciona, pero al mismo tiempo, los algoritmos basados en esta técnica requieren de un elevado tiempo de cómputo que dificulta su implementación en aplicaciones de tiempo real. En este trabajo se presenta un algoritmo basado en visión estéreo para la detección tanto de obstáculos como de espacios transitables en entornos urbanos y que ha sido implementado principalmente en GPU (Unidad de Procesamiento Gráfico para reducir el tiempo de cómputo y conseguir un funcionamiento en tiempo real. Abstract: Both advanced driver assistance systems (ADAS applied to the improvement of road safety, and autonomous navigation vehicle systems require more and more complex sensors and algorithms capable of obtaining and interpreting the information of the road environment. The greatest difficulties arise in analysing the information of the urban environments, because of the large number of elements which have different characteristics in urban areas. These systems require to interpret the information in real time to improve the decision-making. On the other hand, the stereo vision is usable in modeling systems because of the great amount of information that it provides, but at the

Algoritmo Tabú para un problema de distribución de espacios || Tabu search algorithm for a room allocation problem

Directory of Open Access Journals (Sweden)

Molina Luque, Julián

2006-06-01

Full Text Available La distribución de espacios es un problema que habitualmente se presenta en situaciones reales cuando se deben asignar simultáneamente diferentes conjuntos de espacios (despachos, habitaciones, salas, etc. distribuidos entre edificios y/o plantas entre varios grupos de personas de tal forma que se minimicen las distancias entre los espacios asignados a cada grupo y lasede de dicho grupo. Esta situación da lugar a un problema combinatorio con una función objetivo cuadrática, lo cual complica enormemente su resolución mediante un método exacto. Por este motivo, proponemos para su resolución un metaheurístico basado en Búsqueda Tabú con dos grupos de movimientos claramente diferenciados: intercambio de despachos y reasignación de sedes. Finalmente, aplicamos dicho algoritmo a un caso real en la Universidad Pablo de Olavide de Sevilla (España.

Algoritmo del murciélago virtual en el desarrollo de la Integral de Duhamel para sistemas estructurales con un grado de libertad

Directory of Open Access Journals (Sweden)

Sergio Vanegas

2013-01-01

Full Text Available En este artículo se propone el uso del algoritmo de optimización de murciélagos virtuales para resolver la Integral de Duhamel en sistemas dinámicos con un grado de libertad. Se desarrollaron ejercicios a titulo demostrativo, para el cálculo de máximos globales. Los resultados fueron muy comparables, tanto en precisión, como en exactitud frente a aquellos obtenidos por otros métodos de cálculo. Se utilizó igualmente el acelerograma del sismo de Chile (2010, para el que se reporta la respuesta dinámica y el desplazamiento máximo. Se variaron para estos ejemplos la cantidad de murciélagos virtuales notándose su influencia sobre el tiempo de computación.

Electrochemical oxidation of iron and alkalinity generation for efficient sulfide control in sewers.

Science.gov (United States)

Lin, Hui-Wen; Kustermans, Caroline; Vaiopoulou, Eleni; Prévoteau, Antonin; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

2017-07-01

The addition of iron salts is one of the most commonly used dosing strategies for sulfide control in sewers. However, iron salts decrease the sewage pH which not only reduces the effectiveness of sulfide precipitation but also enhances the release of residual sulfide to the sewer atmosphere. Equally important, concentrated iron salt solutions are corrosive and their frequent transport, handling, and on-site storage often come with Occupational Health and Safety (OH&S) concerns. Here, we experimentally demonstrated a novel sulfide control approach using electrochemical systems with parallel placed iron electrodes. This enabled combining anodic dissolved iron species release with cathodic hydroxyl anion production, which alleviates all the aforementioned concerns. A long-term experiment was successfully carried out achieving an average sulfide removal efficiency of 95.4 ± 4.4% at low voltage input of 2.90 ± 0.54 V over the course of 8 weeks. This electrochemical method was demonstrated to successfully achieve efficient sulfide control. In addition, it increases the sewage pH, thereby overcoming the drawbacks associated with the pH decrease in the case of conventional iron salt dosing. Ferrous ions were produced at an overall coulombic efficiency (CE) of 98.2 ± 1.2%, whereas oxygen evolution and direct sulfide oxidation were not observed. Short-term experiments showed that increasing either inter-electrode gap or current density increased the cell voltage associated with the increase in the ohmic drop of the system. Overall, this study highlights the practical potential of in-situ generation of dissolved iron species and simultaneous hydroxyl anion generation for efficient sulfide control in sewers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Highly efficient generation of GGTA1 biallelic knockout inbred mini-pigs with TALENs.

Directory of Open Access Journals (Sweden)

Jige Xin

Full Text Available Inbred mini-pigs are ideal organ donors for future human xenotransplantations because of their clear genetic background, high homozygosity, and high inbreeding endurance. In this study, we chose fibroblast cells from a highly inbred pig line called Banna mini-pig inbred line (BMI as donor nuclei for nuclear transfer, combining with transcription activator-like effector nucleases (TALENs and successfully generated α-1,3-galactosyltransferase (GGTA1 gene biallelic knockout (KO pigs. To validate the efficiency of TALEN vectors, in vitro-transcribed TALEN mRNAs were microinjected into one-cell stage parthenogenetically activated porcine embryos. The efficiency of indel mutations at the GGTA1-targeting loci was as high as 73.1% (19/26 among the parthenogenetic blastocysts. TALENs were co-transfected into porcine fetal fibroblasts of BMI with a plasmid containing neomycin gene. The targeting efficiency reached 89.5% (187/209 among the survived cell clones after a 10 d selection. More remarkably 27.8% (58/209 of colonies were biallelic KO. Five fibroblast cell lines with biallelic KO were chosen as nuclear donors for somatic cell nuclear transfer (SCNT. Three miniature piglets with biallelic mutations of the GGTA1 gene were achieved. Gal epitopes on the surface of cells from all the three biallelic KO piglets were completely absent. The fibroblasts from the GGTA1 null piglets were more resistant to lysis by pooled complement-preserved normal human serum than those from wild-type pigs. These results indicate that a combination of TALENs technology with SCNT can generate biallelic KO pigs directly with high efficiency. The GGTA1 null piglets with inbred features created in this study can provide a new organ source for xenotransplantation research.

Efficiency of defect specific maintenance od steam generator tubes: the case of ODSCC

International Nuclear Information System (INIS)

Cizelj, L.; Dvorsek, T.

1996-01-01

The outside diameter stress corrosion cracking at tube support plates became the dominating ageing mechanism in steam generators tubes made of Inconel 600. A variety of maintenance approaches were developed and implemented worldwide to deal with this mechanism. Despite different philosophical and physical backgrounds implemented, all of the applied approaches satisfy the relevant regulatory requirements. For our purpose, the maintenance approach consist of: (1) inspection of tubes, (2) accepting or rejecting the defective tube and (3) plugging of rejected tubes. The problem of selecting an optimal maintenance approach is raised in the paper. Consequently, a method comparing the efficiency of applicable maintenance approaches is proposed. The efficiency is defined by three parameters: (a) number of plugged tubes, (b) probability of steam generator tube rupture and (c) predicted accidental leak rates through the defects. An original probabilistic model is proposed to quantify the probability of tube rupture, while procedures available in literature were used to define the accidental leak rates. The numerical example considers the data from Krsko NPP (Westinghouse 632 MWe). The maintenance approaches analyzed include: (i) no repair at all, (ii) traditional defect depth (40%) based maintenance, (iii) alternate plugging criterion (bobbin coil voltage as defined by EPRI and U.S. NRC) and (iv) combined traditional and alternate approach. Advantages of the defect specific approaches (iii) and (iv) over the traditional one (defect depth) are clearly shown. A brief discussion on the optimization of safe life of steam generator is given. (author)

Design and optimization of a high-efficiency array generator in the mid-IR with binary subwavelength grooves.

Science.gov (United States)

Bloom, Guillaume; Larat, Christian; Lallier, Eric; Lee-Bouhours, Mane-Si Laure; Loiseaux, Brigitte; Huignard, Jean-Pierre

2011-02-10

We have designed a high-efficiency array generator composed of subwavelength grooves etched in a GaAs substrate for operation at 4.5 μm. The method used combines rigorous coupled wave analysis with an optimization algorithm. The optimized beam splitter has both a high efficiency (∼96%) and a good intensity uniformity (∼0.2%). The fabrication error tolerances are numerically calculated, and it is shown that this subwavelength array generator could be fabricated with current electron beam writers and inductively coupled plasma etching. Finally, we studied the effect of a simple and realistic antireflection coating on the performance of the beam splitter.

Efficient identification of opportunities for Distributed Generation based on Smart Grid Technology

DEFF Research Database (Denmark)

Mutule, Anna; Obushevs, Artjoms; Lvov, Aleksandr

2013-01-01

The paper presents the main goals and achievements of the Smart Grids ERA-NET project named “Efficient identification of opportunities for Distributed Generation based on Smart Grid Technology (SmartGen)” during the second stage of project implementation. A description of Smart Grid Technology (S......) models developed within the framework of the project is given. The performed study cases where the SGT-models were implemented to analyze the impact of the electrical grid are discussed....

Efficient generation of continuous-wave yellow-orange light using sum-frequency in periodically poled KTP

DEFF Research Database (Denmark)

Janousek, Jiri; Johansson, Sandra; Tidemand-Lichtenberg, Peter

We present highly efficient sum-frequency generation between two CW 1064 and 1342 nm laser lines of two Nd:YVO4 lasers using periodically poled KTP. This is an all solid-state light source in the yellow-orange spectral range....

Fiber-Based, Double-Sided, Reduced Graphene Oxide Films for Efficient Solar Vapor Generation.

Science.gov (United States)

Guo, Ankang; Ming, Xin; Fu, Yang; Wang, Gang; Wang, Xianbao

2017-09-06

Solar vapor generation is a promising and whole new branch of photothermal conversion for harvesting solar energy. Various materials and devices for solar thermal conversion were successively produced and reported for higher solar energy utilization in the past few years. Herein, a compact device of reduced graphene oxides (rGO) and paper fibers was designed and assembled for efficient solar steam generation under light illumination, and it consists of water supply pipelines (WSP), a thermal insulator (TI) and a double-sided absorbing film (DSF). Heat localization is enabled by the black DSF due to its broad absorption of sunlight. More importantly, the heat transfer, from the hot DSF to the cold base fluid (water), was suppressed by TI with a low thermal conductivity. Meanwhile, bulk water was continuously transported to the DSF by WSP through TI, which was driven by the surface energy and surface tension based on the capillary effect. The effects of reduction degrees of rGO on the photothermal conversion were explored, and the evaporation efficiency reached 89.2% under one sun with 60 mg rGO. This new microdevice provided a basic technical support for distillation, desalination, sewage treatment, and related technologies.

Vertically Aligned Graphene Sheets Membrane for Highly Efficient Solar Thermal Generation of Clean Water.

Science.gov (United States)

Zhang, Panpan; Li, Jing; Lv, Lingxiao; Zhao, Yang; Qu, Liangti

2017-05-23

Efficient utilization of solar energy for clean water is an attractive, renewable, and environment friendly way to solve the long-standing water crisis. For this task, we prepared the long-range vertically aligned graphene sheets membrane (VA-GSM) as the highly efficient solar thermal converter for generation of clean water. The VA-GSM was prepared by the antifreeze-assisted freezing technique we developed, which possessed the run-through channels facilitating the water transport, high light absorption capacity for excellent photothermal transduction, and the extraordinary stability in rigorous conditions. As a result, VA-GSM has achieved average water evaporation rates of 1.62 and 6.25 kg m -2 h -1 under 1 and 4 sun illumination with a superb solar thermal conversion efficiency of up to 86.5% and 94.2%, respectively, better than that of most carbon materials reported previously, which can efficiently produce the clean water from seawater, common wastewater, and even concentrated acid and/or alkali solutions.

High-Order Dielectric Metasurfaces for High-Efficiency Polarization Beam Splitters and Optical Vortex Generators

Science.gov (United States)

Guo, Zhongyi; Zhu, Lie; Guo, Kai; Shen, Fei; Yin, Zhiping

2017-08-01

In this paper, a high-order dielectric metasurface based on silicon nanobrick array is proposed and investigated. By controlling the length and width of the nanobricks, the metasurfaces could supply two different incremental transmission phases for the X-linear-polarized (XLP) and Y-linear-polarized (YLP) light with extremely high efficiency over 88%. Based on the designed metasurface, two polarization beam splitters working in high-order diffraction modes have been designed successfully, which demonstrated a high transmitted efficiency. In addition, we have also designed two vortex-beam generators working in high-order diffraction modes to create vortex beams with the topological charges of 2 and 3. The employment of dielectric metasurfaces operating in high-order diffraction modes could pave the way for a variety of new ultra-efficient optical devices.

High efficiency, monolithic fiber chirped pulse amplification system for high energy femtosecond pulse generation.

Science.gov (United States)

Peng, Xiang; Kim, Kyungbum; Mielke, Michael; Jennings, Stephen; Masor, Gordon; Stohl, Dave; Chavez-Pirson, Arturo; Nguyen, Dan T; Rhonehouse, Dan; Zong, Jie; Churin, Dmitriy; Peyghambarian, N

2013-10-21

A novel monolithic fiber-optic chirped pulse amplification (CPA) system for high energy, femtosecond pulse generation is proposed and experimentally demonstrated. By employing a high gain amplifier comprising merely 20 cm of high efficiency media (HEM) gain fiber, an optimal balance of output pulse energy, optical efficiency, and B-integral is achieved. The HEM amplifier is fabricated from erbium-doped phosphate glass fiber and yields gain of 1.443 dB/cm with slope efficiency >45%. We experimentally demonstrate near diffraction-limited beam quality and near transform-limited femtosecond pulse quality at 1.55 µm wavelength. With pulse energy >100 µJ and pulse duration of 636 fs (FWHM), the peak power is estimated to be ~160 MW. NAVAIR Public Release Distribution Statement A-"Approved for Public release; distribution is unlimited".

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

Directory of Open Access Journals (Sweden)

Lopez, F.

2004-07-01

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

Measuring efficiency and productivity change in power electric generation management companies by using data envelopment analysis: A case study

International Nuclear Information System (INIS)

Fallahi, Alireza; Ebrahimi, Reza; Ghaderi, S.F.

2011-01-01

This paper provides an empirical analysis of the determinants of energy efficiency in 32 power electric generation management companies over the period 2005–2009. The study uses non-parametric Data Envelopment Analysis (DEA) to estimate the relative technical efficiency and productivity change of these companies. In order to verify the stability of our DEA model and the importance of each input variable, a stability test is also conducted. The results of the study indicate that average technical efficiency of companies decreased during the study period. Nearly half of the companies (14) are below this average level of 88.7% for five years. Moreover, it is shown that the low increase of productivity changes is more related to low efficiency rather than technology changes. -- Highlights: ► DEA was applied on the 32 power electric generation management companies. ► A stability test is applied to verify the stability of DEA model. ► Average technical efficiency of companies decreased during the study period. ► The low increase of productivity changes is more related to low efficiency changes.

Desarrollo de un algoritmo para la generación y elección de soluciones de corte en la operación de canteo y despuntado en aserraderos

OpenAIRE

Francisco Vergara González; Felipe Baesler Abufarde; Mario Ramos Maldonado

2011-01-01

En este trabajo se desarrolló un algoritmo que integra las mejores prácticas aplicadas en los aserraderos y una metodología de análisis geométrico de líneas de corte. La aplicación fue programada en lenguaje C++, siendo alimentada con las dimensiones de las piezas deseadas de producir, sus respectivos precios y la geometría en 2-D de la tapa a cortar, generando como resultado una solución de corte en ancho y largo para tapa ingresada. Las soluciones obtenidas se compararon con un patrón que c...

Magnet Free Generators - 3rd Generation Wind Turbine Generators

DEFF Research Database (Denmark)

Jensen, Bogi Bech; Mijatovic, Nenad; Henriksen, Matthew Lee

2013-01-01

This paper presents an introduction to superconducting wind turbine generators, which are often referred to as 3rd generation wind turbine generators. Advantages and challenges of superconducting generators are presented with particular focus on possible weight and efficiency improvements. A comp...

Highly efficient generation of knock-in transgenic medaka by CRISPR/Cas9-mediated genome engineering.

Science.gov (United States)

Watakabe, Ikuko; Hashimoto, Hisashi; Kimura, Yukiko; Yokoi, Saori; Naruse, Kiyoshi; Higashijima, Shin-Ichi

2018-01-01

Medaka ( Oryzias latipes ) is a popular animal model used in vertebrate genetic analysis. Recently, an efficient (~ 30%) knock-in system via non-homologous end joining (NHEJ) was established in zebrafish using the CRISPR/Cas9 system. If the same technique were applicable in medaka, it would greatly expand the usefulness of this model organism. The question of the applicability of CRISPR/Cas9 in medaka, however, has yet to be addressed. We report the highly efficient generation of knock-in transgenic medaka via non-homologous end joining (NHEJ). Donor plasmid containing a heat-shock promoter and a reporter gene was co-injected with a short guide RNA (sgRNA) targeted for genome digestion, an sgRNA targeted for donor plasmid digestion, and Cas9 mRNA. Broad transgene expression in the expression domain of a target gene was observed in approximately 25% of injected embryos. By raising these animals, we established stable knock-in transgenic fish with several different constructs for five genetic loci, obtaining transgenic founders at efficiencies of > 50% for all five loci. Further, we show that the method is useful for obtaining mutant alleles. In the experiments where transgene integrations were targeted between the transcription start site and the initiation methionine, the resultant transgenic fish became mutant alleles. With its simplicity, design flexibility, and high efficiency, we propose that CRISPR/Cas9-mediated knock-in via NHEJ will become a standard method for the generation of transgenic and mutant medaka.

Adaptação e aplicabilidade de um algoritmo de diurético para pacientes com insuficiência cardíaca

Directory of Open Access Journals (Sweden)

Maria Karolina Echer Ferreira Feijó

2013-06-01

Full Text Available FUNDAMENTO: Estados congestivos podem ser identificados e manejados através de algoritmos como o Diuretic Treatment Algorithm (DTA para ajuste de diurético por telefone, com enfoque na avaliação clínica. Porém, o DTA está disponível somente em língua inglesa. OBJETIVO: Adaptar o DTA e testar sua aplicabilidade para uso no Brasil em pacientes ambulatoriais com IC. MÉTODOS: Seguiram-se as etapas de tradução, síntese, retrotradução, avaliação por comitê de especialistas e pré-teste (aplicabilidade clínica por meio de ensaio clínico randomizado. O DTA foi denominado, na versão para o Brasil, algoritmo de ajuste de diurético (AAD. Os pacientes foram randomizados para grupo intervenção (GI - ajuste de diurético conforme o AAD - ou grupo controle (GC - ajuste convencional. Foi avaliado o escore clínico de congestão (ECC e o peso para ambos os grupos. RESULTADOS: Foram realizadas 12 modificações no DTA. Incluíram-se 34 pacientes. Para aqueles congestos, o aumento de diurético guiado pelo AAD resultou em maior resolução da congestão, com redução de dois pontos no ECC para 50% da amostra -2 (-3,5; -1,0, enquanto a mediana para o GC foi 0 (-1,25; -1,0, (p < 0,001. A mediana de variação de peso foi maior no GI -1,4 (-1,7; -0,5 quando comparado ao GC 0,1 (1,2; -0,6, p = 0,001. CONCLUSÕES: O ADD mostrou-se aplicável na prática clínica após adaptação e parece resultar em melhor controle da congestão em pacientes com IC. A efetividade clínica da ferramenta merece ser testada em amostra maior de pacientes visando sua validação para uso no Brasil (Universal Trial Number: U1111-1130-5749 (Arq Bras Cardiol. 2013; [online]. ahead print, PP.0-0.

Efficient green phosphorescent tandem organic light emitting diodes with solution processable mixed hosts charge generating layer

Energy Technology Data Exchange (ETDEWEB)

Talik, N.A.; Yeoh, K.H.; Ng, C.Y.B [Low Dimensional Research Center, Department of Physics, University Malaya, 50603 Kuala Lumpur (Malaysia); ItraMAS Corporation. Sdn. Bhd., 542A-B Mukim 1, Lorong Perusahaan Baru 2, Kawasan Perindustrian, Perai 13600, Penang (Malaysia); Yap, B.K. [Center of Microelectronic and Nanotechnology Engineering (CeMNE), College of Engineering, Universiti Tenaga Nasional, Jln. Uniten-Ikram, 4300 Kajang, Selangor (Malaysia); Woon, K.L., E-mail: ph7klw76@um.edu.my [Low Dimensional Research Center, Department of Physics, University Malaya, 50603 Kuala Lumpur (Malaysia)

2014-10-15

A novel solution processable charge generating layer (CGL) that consists of 1,4,5,8,9,11-hexaazatriphenylene hexacarbonitrile (HATCN{sub 6})/Poly(N-vinylcarbazole) (PVK): 1,1-bis-(4-bis(4-tolyl)-aminophenyl) cyclohexene (TAPC) for a tandem green phosphorescent organic light emitting diode (PHOLED) is demonstrated. The use of orthogonal solvent to dissolve HATCN{sub 6} and PVK:TAPC is the key to overcome the interface erosion problem for the solution processed CGL. The current efficiency of the 2 wt% TAPC mixed with PVK is the highest at 24.2 cd/A, which is more than three-folds higher than that of the single device at 1000 cd/m{sup 2}. - Highlights: • A solution processable tandem OLED is built using a novel charge generating layer. • HATCN{sub 6} and PVK:TAPC are shown to be effective charge generating layers. • The turn on voltages for tandem devices are almost similar to single unit. • 2 wt% TAPC blended with PVK exhibits three-folds increase in efficiency.

Efficient 1.5-μm Raman generation in ethane-filled hollow-core fiber

Science.gov (United States)

Chen, Yubin; Gu, Bo; Wang, Zefeng; Lu, Qisheng

2016-11-01

We demonstrated for the first time a novel and effective method for obtaining both high peak-power and narrow linewidth 1.5 μm fiber sources through gas Raman effect in hollow core fibers. An Ethane-filled ice-cream antiresonance hollow-core fiber is pumped with a high peak-power pulse 1064 nm microchip laser, generating 1552.7 nm Stokes wave by pure vibrational stimulated Raman scattering of ethane molecules. A maximum peak-power of about 400 kW is achieved with 6 meter fiber length at 2 bar pressure, and the linewidth is about 6.3 GHz. The maximum Raman conversion efficiency of 1064 nm to 1552.7 nm is about 38%, and the corresponding laser slope efficiency is about 61.5%.

Resource-efficient generation of linear cluster states by linear optics with postselection

International Nuclear Information System (INIS)

Uskov, D B; Alsing, P M; Fanto, M L; Szep, A; Smith, A M; Kaplan, L; Kim, R

2015-01-01

We report on theoretical research in photonic cluster-state computing. Finding optimal schemes of generating non-classical photonic states is of critical importance for this field as physically implementable photon–photon entangling operations are currently limited to measurement-assisted stochastic transformations. A critical parameter for assessing the efficiency of such transformations is the success probability of a desired measurement outcome. At present there are several experimental groups that are capable of generating multi-photon cluster states carrying more than eight qubits. Separate photonic qubits or small clusters can be fused into a single cluster state by a probabilistic optical CZ gate conditioned on simultaneous detection of all photons with 1/9 success probability for each gate. This design mechanically follows the original theoretical scheme of cluster state generation proposed more than a decade ago by Raussendorf, Browne and Briegel. The optimality of the destructive CZ gate in application to linear optical cluster state generation has not been analyzed previously. Our results reveal that this method is far from the optimal one. Employing numerical optimization we have identified that the maximal success probability of fusing n unentangled dual-rail optical qubits into a linear cluster state is equal to (1/2) n−1 ; an m-tuple of photonic Bell pair states, commonly generated via spontaneous parametric down-conversion, can be fused into a single cluster with the maximal success probability of (1/4) m−1 . (paper)

Efficient FIR Filter Implementations for Multichannel BCIs Using Xilinx System Generator

Directory of Open Access Journals (Sweden)

Usman Ghani

2018-01-01

Full Text Available Background. Brain computer interface (BCI is a combination of software and hardware communication protocols that allow brain to control external devices. Main purpose of BCI controlled external devices is to provide communication medium for disabled persons. Now these devices are considered as a new way to rehabilitate patients with impunities. There are certain potentials present in electroencephalogram (EEG that correspond to specific event. Main issue is to detect such event related potentials online in such a low signal to noise ratio (SNR. In this paper we propose a method that will facilitate the concept of online processing by providing an efficient filtering implementation in a hardware friendly environment by switching to finite impulse response (FIR. Main focus of this research is to minimize latency and computational delay of preprocessing related to any BCI application. Four different finite impulse response (FIR implementations along with large Laplacian filter are implemented in Xilinx System Generator. Efficiency of 25% is achieved in terms of reduced number of coefficients and multiplications which in turn reduce computational delays accordingly.

Efficient FIR Filter Implementations for Multichannel BCIs Using Xilinx System Generator.

Science.gov (United States)

Ghani, Usman; Wasim, Muhammad; Khan, Umar Shahbaz; Mubasher Saleem, Muhammad; Hassan, Ali; Rashid, Nasir; Islam Tiwana, Mohsin; Hamza, Amir; Kashif, Amir

2018-01-01

Background . Brain computer interface (BCI) is a combination of software and hardware communication protocols that allow brain to control external devices. Main purpose of BCI controlled external devices is to provide communication medium for disabled persons. Now these devices are considered as a new way to rehabilitate patients with impunities. There are certain potentials present in electroencephalogram (EEG) that correspond to specific event. Main issue is to detect such event related potentials online in such a low signal to noise ratio (SNR). In this paper we propose a method that will facilitate the concept of online processing by providing an efficient filtering implementation in a hardware friendly environment by switching to finite impulse response (FIR). Main focus of this research is to minimize latency and computational delay of preprocessing related to any BCI application. Four different finite impulse response (FIR) implementations along with large Laplacian filter are implemented in Xilinx System Generator. Efficiency of 25% is achieved in terms of reduced number of coefficients and multiplications which in turn reduce computational delays accordingly.

Efficient computation of clipped Voronoi diagram for mesh generation

KAUST Repository

Yan, Dongming

2013-04-01

The Voronoi diagram is a fundamental geometric structure widely used in various fields, especially in computer graphics and geometry computing. For a set of points in a compact domain (i.e. a bounded and closed 2D region or a 3D volume), some Voronoi cells of their Voronoi diagram are infinite or partially outside of the domain, but in practice only the parts of the cells inside the domain are needed, as when computing the centroidal Voronoi tessellation. Such a Voronoi diagram confined to a compact domain is called a clipped Voronoi diagram. We present an efficient algorithm to compute the clipped Voronoi diagram for a set of sites with respect to a compact 2D region or a 3D volume. We also apply the proposed method to optimal mesh generation based on the centroidal Voronoi tessellation. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.

Efficient computation of clipped Voronoi diagram for mesh generation

KAUST Repository

Yan, Dongming; Wang, Wen Ping; Lé vy, Bruno L.; Liu, Yang

2013-01-01

The Voronoi diagram is a fundamental geometric structure widely used in various fields, especially in computer graphics and geometry computing. For a set of points in a compact domain (i.e. a bounded and closed 2D region or a 3D volume), some Voronoi cells of their Voronoi diagram are infinite or partially outside of the domain, but in practice only the parts of the cells inside the domain are needed, as when computing the centroidal Voronoi tessellation. Such a Voronoi diagram confined to a compact domain is called a clipped Voronoi diagram. We present an efficient algorithm to compute the clipped Voronoi diagram for a set of sites with respect to a compact 2D region or a 3D volume. We also apply the proposed method to optimal mesh generation based on the centroidal Voronoi tessellation. Crown Copyright © 2011 Published by Elsevier Ltd. All rights reserved.

Influence of thermodynamic properties of a thermo-acoustic emitter on the efficiency of thermal airborne ultrasound generation.

Science.gov (United States)

Daschewski, M; Kreutzbruck, M; Prager, J

2015-12-01

In this work we experimentally verify the theoretical prediction of the recently published Energy Density Fluctuation Model (EDF-model) of thermo-acoustic sound generation. Particularly, we investigate experimentally the influence of thermal inertia of an electrically conductive film on the efficiency of thermal airborne ultrasound generation predicted by the EDF-model. Unlike widely used theories, the EDF-model predicts that the thermal inertia of the electrically conductive film is a frequency-dependent parameter. Its influence grows non-linearly with the increase of excitation frequency and reduces the efficiency of the ultrasound generation. Thus, this parameter is the major limiting factor for the efficient thermal airborne ultrasound generation in the MHz-range. To verify this theoretical prediction experimentally, five thermo-acoustic emitter samples consisting of Indium-Tin-Oxide (ITO) coatings of different thicknesses (from 65 nm to 1.44 μm) on quartz glass substrates were tested for airborne ultrasound generation in a frequency range from 10 kHz to 800 kHz. For the measurement of thermally generated sound pressures a laser Doppler vibrometer combined with a 12 μm thin polyethylene foil was used as the sound pressure detector. All tested thermo-acoustic emitter samples showed a resonance-free frequency response in the entire tested frequency range. The thermal inertia of the heat producing film acts as a low-pass filter and reduces the generated sound pressure with the increasing excitation frequency and the ITO film thickness. The difference of generated sound pressure levels for samples with 65 nm and 1.44 μm thickness is in the order of about 6 dB at 50 kHz and of about 12 dB at 500 kHz. A comparison of sound pressure levels measured experimentally and those predicted by the EDF-model shows for all tested emitter samples a relative error of less than ±6%. Thus, experimental results confirm the prediction of the EDF-model and show that the model can

Efficient mRNA delivery with graphene oxide-polyethylenimine for generation of footprint-free human induced pluripotent stem cells.

Science.gov (United States)

Choi, Hye Yeon; Lee, Tae-Jin; Yang, Gwang-Mo; Oh, Jaesur; Won, Jihye; Han, Jihae; Jeong, Gun-Jae; Kim, Jongpil; Kim, Jin-Hoi; Kim, Byung-Soo; Cho, Ssang-Goo

2016-08-10

Clinical applications of induced pluripotent stem cells (iPSCs) require development of technologies for the production of "footprint-free" (gene integration-free) iPSCs, which avoid the potential risk of insertional mutagenesis in humans. Previously, several studies have shown that mRNA transfer can generate "footprint-free" iPSCs, but these studies did not use a delivery vehicle and thus repetitive daily transfection was required because of mRNA degradation. Here, we report an mRNA delivery system employing graphene oxide (GO)-polyethylenimine (PEI) complexes for the efficient generation of "footprint-free" iPSCs. GO-PEI complexes were found to be very effective for loading mRNA of reprogramming transcription factors and protection from mRNA degradation by RNase. Dynamic suspension cultures of GO-PEI/RNA complexes-treated cells dramatically increased the reprogramming efficiency and successfully generated rat and human iPSCs from adult adipose tissue-derived fibroblasts without repetitive daily transfection. The iPSCs showed all the hallmarks of pluripotent stem cells including expression of pluripotency genes, epigenetic reprogramming, and differentiation into the three germ layers. These results demonstrate that mRNA delivery using GO-PEI-RNA complexes can efficiently generate "footprint-free" iPSCs, which may advance the translation of iPSC technology into the clinical settings. Copyright © 2016. Published by Elsevier B.V.

Influence of the oxidiser gas composition on the overtone generation efficiency of a supersonic cw chemical HF laser

International Nuclear Information System (INIS)

Konkin, S V; Fedorov, Igor' A; Rebone, Vitalii K; Rotinyan, Mikhail A; Tret'yakov, Nikolai E; Galaev, I I; Moroz, M V; Tomashevich, N N

1998-01-01

An experimental investigation was made of the influence of the chemical composition of the oxidiser gas in an atomic-fluorine generator on the efficiency of generation of radiation representing the first overtone of the HF molecule in a self-contained supersonic cw chemical HF laser with the active medium 70 cm long. The optimal chemical composition was different for the fundamental and overtone transitions. A specific output energy of 84 J g -1 at a specific mass flow rate of 0.13 g s -1 cm -2 through the nozzle array was achieved by optimisation of a linear three-mirror optical cavity at the 1.33 - 1.35 μm wavelengths. The overtone radiation power generated in the whole of the active medium was 7.5 kW, corresponding to a 41% efficiency of energy conversion to an overtone. (lasers, active media)

An efficient algorithm for global periodic orbits generation near irregular-shaped asteroids

Science.gov (United States)

Shang, Haibin; Wu, Xiaoyu; Ren, Yuan; Shan, Jinjun

2017-07-01

Periodic orbits (POs) play an important role in understanding dynamical behaviors around natural celestial bodies. In this study, an efficient algorithm was presented to generate the global POs around irregular-shaped uniformly rotating asteroids. The algorithm was performed in three steps, namely global search, local refinement, and model continuation. First, a mascon model with a low number of particles and optimized mass distribution was constructed to remodel the exterior gravitational potential of the asteroid. Using this model, a multi-start differential evolution enhanced with a deflection strategy with strong global exploration and bypassing abilities was adopted. This algorithm can be regarded as a search engine to find multiple globally optimal regions in which potential POs were located. This was followed by applying a differential correction to locally refine global search solutions and generate the accurate POs in the mascon model in which an analytical Jacobian matrix was derived to improve convergence. Finally, the concept of numerical model continuation was introduced and used to convert the POs from the mascon model into a high-fidelity polyhedron model by sequentially correcting the initial states. The efficiency of the proposed algorithm was substantiated by computing the global POs around an elongated shoe-shaped asteroid 433 Eros. Various global POs with different topological structures in the configuration space were successfully located. Specifically, the proposed algorithm was generic and could be conveniently extended to explore periodic motions in other gravitational systems.

Evaluación del comportamiento de un algoritmo para la secuenciación en un taller de flujo con tiempos dependientes de la secuencia // Evaluation of the behaviour of a sequences elaboration algorithm in a flow shop with depending on the sequence times.

Directory of Open Access Journals (Sweden)

Alberto Fiol-Zulueta

2010-01-01

Full Text Available ResumenEn el trabajo se realiza la evaluación del comportamiento de un algoritmo propuesto para lasecuenciación en un taller de flujo con tiempos dependientes de la secuencia, utilizando un métodohíbrido basado en el Algoritmo de Búsqueda del Extremo de una Función de un Código Variable y lametaheurística de Búsqueda Dispersa. Asimismo, se analizan casos obtenidos de la aplicación en untaller mecánico de una industria nacional.Palabras claves: secuencias, taller de flujo, metaheurística.____________________________________________________________AbstractIn this paper the evaluation of the behaviour of a proposed algorithm is made for the sequence ofevents in a stream flow in a workshop with dependent moments of the sequence using a hybridmethod based on theSEARCH OF THE EXTREME OF A FUNTION OF A VARIABLE CODE ALGORITHM AND THEDISPERSED SEARCH METHOD ALGORITHMIn the same way, cases obtained from the application in aworkshop of the national mechanical industry are analysed.Key words: scheduling, flow shop, metahuristic

Efficient Generation of Myostatin Knock-Out Sheep Using CRISPR/Cas9 Technology and Microinjection into Zygotes.

Directory of Open Access Journals (Sweden)

M Crispo

Full Text Available While CRISPR/Cas9 technology has proven to be a valuable system to generate gene-targeted modified animals in several species, this tool has been scarcely reported in farm animals. Myostatin is encoded by MSTN gene involved in the inhibition of muscle differentiation and growth. We determined the efficiency of the CRISPR/Cas9 system to edit MSTN in sheep and generate knock-out (KO animals with the aim to promote muscle development and body growth. We generated CRISPR/Cas9 mRNAs specific for ovine MSTN and microinjected them into the cytoplasm of ovine zygotes. When embryo development of CRISPR/Cas9 microinjected zygotes (n = 216 was compared with buffer injected embryos (n = 183 and non microinjected embryos (n = 173, cleavage rate was lower for both microinjected groups (P<0.05 and neither was affected by CRISPR/Cas9 content in the injected medium. Embryo development to blastocyst was not affected by microinjection and was similar among the experimental groups. From 20 embryos analyzed by Sanger sequencing, ten were mutant (heterozygous or mosaic; 50% efficiency. To obtain live MSTN KO lambs, 53 blastocysts produced after zygote CRISPR/Cas9 microinjection were transferred to 29 recipient females resulting in 65.5% (19/29 of pregnant ewes and 41.5% (22/53 of newborns. From 22 born lambs analyzed by T7EI and Sanger sequencing, ten showed indel mutations at MSTN gene. Eight showed mutations in both alleles and five of them were homozygous for indels generating out-of frame mutations that resulted in premature stop codons. Western blot analysis of homozygous KO founders confirmed the absence of myostatin, showing heavier body weight than wild type counterparts. In conclusion, our results demonstrate that CRISPR/Cas9 system was a very efficient tool to generate gene KO sheep. This technology is quick and easy to perform and less expensive than previous techniques, and can be applied to obtain genetically modified animal models of interest for

An efficient algorithm for generating random number pairs drawn from a bivariate normal distribution

Science.gov (United States)

Campbell, C. W.

1983-01-01

An efficient algorithm for generating random number pairs from a bivariate normal distribution was developed. Any desired value of the two means, two standard deviations, and correlation coefficient can be selected. Theoretically the technique is exact and in practice its accuracy is limited only by the quality of the uniform distribution random number generator, inaccuracies in computer function evaluation, and arithmetic. A FORTRAN routine was written to check the algorithm and good accuracy was obtained. Some small errors in the correlation coefficient were observed to vary in a surprisingly regular manner. A simple model was developed which explained the qualities aspects of the errors.

An Efficient Method for Generation of Knockout Human Embryonic Stem Cells Using CRISPR/Cas9 System.

Science.gov (United States)

Bohaciakova, Dasa; Renzova, Tereza; Fedorova, Veronika; Barak, Martin; Kunova Bosakova, Michaela; Hampl, Ales; Cajanek, Lukas

2017-11-01

Human embryonic stem cells (hESCs) represent a promising tool to study functions of genes during development, to model diseases, and to even develop therapies when combined with gene editing techniques such as CRISPR/CRISPR-associated protein-9 nuclease (Cas9) system. However, the process of disruption of gene expression by generation of null alleles is often inefficient and tedious. To circumvent these limitations, we developed a simple and efficient protocol to permanently downregulate expression of a gene of interest in hESCs using CRISPR/Cas9. We selected p53 for our proof of concept experiments. The methodology is based on series of hESC transfection, which leads to efficient downregulation of p53 expression even in polyclonal population (p53 Low cells), here proven by a loss of regulation of the expression of p53 target gene, microRNA miR-34a. We demonstrate that our approach achieves over 80% efficiency in generating hESC clonal sublines that do not express p53 protein. Importantly, we document by a set of functional experiments that such genetically modified hESCs do retain typical stem cells characteristics. In summary, we provide a simple and robust protocol to efficiently target expression of gene of interest in hESCs that can be useful for laboratories aiming to employ gene editing in their hESC applications/protocols.

Ionic liquids in proton exchange membrane fuel cells: Efficient systems for energy generation

Energy Technology Data Exchange (ETDEWEB)

Padilha, Janine C.; Basso, Juliana; da Trindade, Leticia G.; Martini, Emilse M.A.; de Souza, Michele O.; de Souza, Roberto F. [Institute of Chemistry, UFRGS, Av. Bento Goncalves 9500, Porto Alegre 91501-970, P.O. Box 15003 (Brazil)

2010-10-01

Proton exchange membrane fuel cells (PEMFCs) are used in portable devices to generate electrical energy; however, the efficiency of the PEMFC is currently only 40%. This study demonstrates that the efficiency of a PEMFC can be increased to 61% when 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) ionic liquid (IL) is used together with the membrane electrode assembly (MEA). The results for ionic liquids (ILs) 1-butyl-3-methylimidazolium chloride (BMI.Cl) and 1-butyl-3-methylimidazolium tetrafluoroborate (BMI.BF{sub 4}) in aqueous solutions are better than those obtained with pure water. The current and the power densities with IL are at least 50 times higher than those obtained for the PEMFC wetted with pure water. This increase in PEMFC performance can greatly facilitate the use of renewable energy sources. (author)

GTHTR300—A nuclear power plant design with 50% generating efficiency

International Nuclear Information System (INIS)

Sato, Hiroyuki; Yan, Xing L.; Tachibana, Yukio; Kunitomi, Kazuhiko

2014-01-01

Highlights: • GTHTR300 reported 10 years ago is updated. • Cycle and reactor core designs as well as turbine blade material are improved. • The study showed that GTHTR300 is able to yield a net plant efficiency of 50.4%. - Abstract: GTHTR300 is a gas turbine high temperature reactor power generation plant design. The baseline design reported by Japan Atomic Energy Agency a decade ago attained 45.6% net efficiency. Technological improvements have since been made that make further increase in efficiency practical: first, the cycle parameters are upgraded by utilizing the newly acquired design data including those from component tests. Next, the core design is optimized to raise the reactor outlet coolant temperature from the baseline of 850 °C to the level of 950 °C demonstrated on the long-term test reactor operation. Both core physics and thermal hydraulics are investigated to demonstrate the corresponding temperature rise is within the design limit so that the existing fuel design can continue to apply. Finally, an advanced type of turbine blade material that has only recently entered in commercial service in aircraft engine is found to be useable for this design to realize a turbine inlet temperature of 950 °C without requiring blade cooling. As detailed in this paper, these design improvements result in a nearly 5% gain in overall plant efficiency and enable the GTHTR300 to break the 50% efficiency barrier of nuclear plant while using only the existing technologies. This result is expected to contribute to the early market deployment of high temperature gas-cooled reactor

GTHTR300—A nuclear power plant design with 50% generating efficiency

Energy Technology Data Exchange (ETDEWEB)

Sato, Hiroyuki, E-mail: sato.hiroyuki09@jaea.go.jp; Yan, Xing L.; Tachibana, Yukio; Kunitomi, Kazuhiko

2014-08-15

Highlights: • GTHTR300 reported 10 years ago is updated. • Cycle and reactor core designs as well as turbine blade material are improved. • The study showed that GTHTR300 is able to yield a net plant efficiency of 50.4%. - Abstract: GTHTR300 is a gas turbine high temperature reactor power generation plant design. The baseline design reported by Japan Atomic Energy Agency a decade ago attained 45.6% net efficiency. Technological improvements have since been made that make further increase in efficiency practical: first, the cycle parameters are upgraded by utilizing the newly acquired design data including those from component tests. Next, the core design is optimized to raise the reactor outlet coolant temperature from the baseline of 850 °C to the level of 950 °C demonstrated on the long-term test reactor operation. Both core physics and thermal hydraulics are investigated to demonstrate the corresponding temperature rise is within the design limit so that the existing fuel design can continue to apply. Finally, an advanced type of turbine blade material that has only recently entered in commercial service in aircraft engine is found to be useable for this design to realize a turbine inlet temperature of 950 °C without requiring blade cooling. As detailed in this paper, these design improvements result in a nearly 5% gain in overall plant efficiency and enable the GTHTR300 to break the 50% efficiency barrier of nuclear plant while using only the existing technologies. This result is expected to contribute to the early market deployment of high temperature gas-cooled reactor.

Algoritmos genéticos aplicados a la optimización de antenas Yagi-Uda Genetic algorithms applied to Yagi-Uda antenna optimization

Directory of Open Access Journals (Sweden)

Edgardo César De La Asunción López

2009-07-01

Full Text Available En el presente artículo se muestra un proceso de optimización implementado usando algoritmos genéticos. La población inicial del AG está compuesta por 128 cromosomas con 11 genes por cromosoma. Los cromosomas del AG están compuestos por las longitudes y separaciones de los elementos de la antena Yagi-Uda; los rangos de estos genes fueron escogidos siguiendo estándares de diseño para dichas antenas. Los genes pasan un proceso de análisis para medir cada una las antenas de cada generación de del AG para asignar la aptitud de los individuos. Con el fin de verificar los resultados obtenidos, se aplicaron varias pruebas, entre ellas la construcción de una antena Yagi-Uda optimizada a la cual se le midieron y verificaron sus características electromagnéticas.This paper describes an optimization process implemented using Genetic Algorithms. The initial population of the GA is composed of 128 chromosomes with 11 genes per chromosome. The chromosomes of the GA are composed by the length and separations of the elements of the Yagi-Uda antenna; the ranks of this genes where chosen by design standards for such antennas. All genes undergo a process of analysis to assess every one of the antennas of each generation of the GA to assign the fitness of the individuals. In order to verify the obtained results, various tests were made, and among them excel the construction of the optimized Yagi-Uda antenna to measure and verify it electromagnetic characteristics.

Maximización de la función de Verosimilitud de Distribuciones de Probabilidad usando Algoritmos Genéticos

Directory of Open Access Journals (Sweden)

Oscar Arturo Fuentes Mariles

2015-01-01

Full Text Available Tradicionalmente, para obtener los parámetros de una función de distribución con el método de máxima verosimilitud se acostumbra igualar a cero la derivada del logaritmo de la función de verosimilitud y resolver el sistema de ecuaciones no lineales que resulta. La popularidad del procedimiento se debe a su sencillez; sin embargo, cuando la función de verosimilitud no es suficientemente regular, puede llevar a obtener un valor muy alejado del máximo Por ese motivo, en este documento se presenta el uso de un algoritmo genético que permite encontrar los parámetros de la función de distribución (con los que se maximiza directamente la función de verosimilitud, o su logaritmo, sin recurrir a la derivada de los logaritmos de dicha función. Se halló buena concordancia de los resultados respecto a los obtenidos usando un software de uso frecuente en México, para el caso las funciones Gumbel y Gumbel de dos poblaciones. 

Un algoritmo de replanificación en tiempo real basado en un índice de estabilidad de Lyapunov para líneas de metro

Directory of Open Access Journals (Sweden)

A. Berbey

2014-04-01

Full Text Available Resumen: En este trabajo, se propone un nuevo índice basado en el método directo de Lyapunov para el diseño de un algoritmo de reprogramación en tiempo real para líneas de metro. En este estudio se utiliza una versión modificada de un modelo de espacio de estados en tiempo real discreto, que considera los efectos de saturación en la línea de metro. Una vez que el modelo de espacio de estados se ha obtenido, el método directo de Lyapunov se aplica con el fin de analizar la estabilidad del sistema de la línea de metro. Como resultado de este análisis no sólo se propone un nuevo índice de estabilidad, sino también la creación de tres zonas de estabilidad para indicar el estado actual del sistema. Finalmente, se presenta un nuevo algoritmo que permite la reprogramación del calendario de los trenes en tiempo real en presencia de perturbaciones medianas. Abstract: A new Lyapunov-based index for designing a rescheduling algorithm in real time for metro lines has been proposed in this paper. A modified real time discrete space state model which considers saturation effects in the metro line has been utilized in this study. Once the space state model has been obtained, the direct method of Lyapunov is applied in order to analyze the stability of the metro line system. As a result of this analysis not only a new stability index is proposed, but also the establishment of three stability zones to indicate the current state of the system. Finally, a new algorithm which allows the rescheduling of the timetable in the real time of the trains under presence of medium disturbances has been presented. Palabras clave: Sistema de metro, estabilidad de Lyapunov, planificación en tiempo real, Keywords: Metro system, Lyapunov stability, real time planning, traffic regulation

What drives the efficiency of hard coal fuelled electricity generation? : an empirical assessment

OpenAIRE

Hoffmann, Tim; Voigt, Sebastian

2009-01-01

The efficiency of electricity generation in hard coal fired power plants varies considerably from country to country and over time. These differences occur both between developing and developed countries and between industrialised nations. The econometric analysis presented in this paper tests for the reasons of these discrepancies. In this examination abundance of hard coal and the price of hard coal are the two variables of our major interest. We assume that countries with an abundance of h...

High-efficiency photorealistic computer-generated holograms based on the backward ray-tracing technique

Science.gov (United States)

Wang, Yuan; Chen, Zhidong; Sang, Xinzhu; Li, Hui; Zhao, Linmin

2018-03-01

Holographic displays can provide the complete optical wave field of a three-dimensional (3D) scene, including the depth perception. However, it often takes a long computation time to produce traditional computer-generated holograms (CGHs) without more complex and photorealistic rendering. The backward ray-tracing technique is able to render photorealistic high-quality images, which noticeably reduce the computation time achieved from the high-degree parallelism. Here, a high-efficiency photorealistic computer-generated hologram method is presented based on the ray-tracing technique. Rays are parallelly launched and traced under different illuminations and circumstances. Experimental results demonstrate the effectiveness of the proposed method. Compared with the traditional point cloud CGH, the computation time is decreased to 24 s to reconstruct a 3D object of 100 ×100 rays with continuous depth change.

Study on gas turbines. Leading role of high efficiency power generation; Gas turbine kenkyu. Kokoritsu hatsuden no shuyaku wo nerau

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-01-31

This review summarizes research works of Central Research Institute of Electric Power Industry on gas turbines playing a leading role of high efficiency power generation. This article describes historical changes of gas turbine technology, changes and current status from the viewpoint of electric power industry, and development trend in various makers. Increase in the flow-in gas temperature, low NOx combustion technology, use of various fuels, and durability evaluation and improvement technology for high temperature parts are described as technological problems and development trends. The increase in temperature is indispensable for the improvement of efficiency. Materials having heat resistance, anticorrosion and strength are required. Accordingly, Ni-based single crystal super alloy has been developed. Developments of ceramic gas turbine and catalytic combustor are also described. The coal gasification combined power generation is expected as a new power generation technology having availability of various coals, high efficiency, and excellent environmental protection. Development of 1500 {degree}C class combustor for turbines has been promoted. Evaluation and improvement of durability of high temperature parts are also described. For the new utilization technology of gas turbines, repowering and compressed air storage gas turbine power generation technology are introduced. 92 figs., 14 tabs.

A trick to improve the efficiency of generating unweighted B events from BCVEGPY

Science.gov (United States)

Wang, Xian-You; Wu, Xing-Gang

2012-02-01

In the present paper, we provide an addendum to improve the efficiency of generating unweighted events within PYTHIA environment for the generator BCVEGPY2.1 [C.H. Chang, J.X. Wang, X.G. Wu, Comput. Phys. Commun. 174 (2006) 241]. This trick is helpful for experimental simulation. Moreover, the BCVEGPY output has also been improved, i.e. one Les Houches Event common block has been added so as to generate a standard Les Houches Event file that contains the information of the generated B meson and the accompanying partons, which can be more conveniently used for further simulation. New version program summaryTitle of program: BCVEGPY2.1a Catalogue identifier: ADTJ_v2_2 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADTJ_v2_2.html Program obtained from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 166 133 No. of bytes in distributed program, including test data, etc.: 1 655 390 Distribution format: tar.gz Programming language used: FORTRAN 77/90 Computer: Any LINUX based on PC with FORTRAN 77 or FORTRAN 90 and GNU C compiler as well Operating systems: LINUX RAM: About 2.0 MB Classification: 11.2, 11.5 Catalogue identifier of previous version: ADTJ_v2_1 Reference in CPC: Comput. Phys. Commun. 175 (2006) 624 Does the new version supersede the old program: No Nature of physical problem: Hadronic Production of B meson and its excited states Method of solution: To generate weighted and unweighted B events within PYTHIA environment effectively. Restrictions on the complexity of the problem: Hadronic production of ( cb¯)-quarkonium via the gluon-gluon fusion mechanism are given by the 'complete calculation approach'. The simulation of B events is done within PYTHIA environment. Reasons for new version: More and more data are accumulated at the large hadronic collider, it would be possible to make

Efficient generation of monoclonal antibodies against peptide in the context of MHCII using magnetic enrichment.

Science.gov (United States)

Spanier, Justin A; Frederick, Daniel R; Taylor, Justin J; Heffernan, James R; Kotov, Dmitri I; Martinov, Tijana; Osum, Kevin C; Ruggiero, Jenna L; Rust, Blake J; Landry, Samuel J; Jenkins, Marc K; McLachlan, James B; Fife, Brian T

2016-06-13

Monoclonal antibodies specific for foreign antigens, auto-antigens, allogeneic antigens and tumour neo-antigens in the context of major histocompatibility complex II (MHCII) are highly desirable as novel immunotherapeutics. However, there is no standard protocol for the efficient generation of monoclonal antibodies that recognize peptide in the context of MHCII, and only a limited number of such reagents exist. In this report, we describe an approach for the generation and screening of monoclonal antibodies specific for peptide bound to MHCII. This approach exploits the use of recombinant peptide:MHC monomers as immunogens, and subsequently relies on multimers to pre-screen and magnetically enrich the responding antigen-specific B cells before fusion and validation, thus saving significant time and reagents. Using this method, we have generated two antibodies enabling us to interrogate antigen presentation and T-cell activation. This methodology sets the standard to generate monoclonal antibodies against the peptide-MHCII complexes.

Estudo da ocorrência de cyberbullying contra professores na rede social Twitter por meio de um algoritmo de classificação bayesiano

Directory of Open Access Journals (Sweden)

Rafael José de Alencar Almeida

2012-04-01

Full Text Available O presente trabalho pretende contribuir com o mapeamento e a mensuração da ocorrência da violência virtual contra professores na rede social Twitter, por meio de técnicas computacionais baseadas em mineração de dados da Internet (web mining e aprendizagem de máquina (machine learning. Para tal, foi realizada, durante uma semana, a coleta de postagens referentes a professores na rede social, as quais foram normalizadas e submetidas a um algoritmo de classificação Bayesiano capaz de realizar automaticamente a categorização do teor das mensagens como positivas, negativas ou neutras. Como resultado, obteve-se uma visualização gráfica hierárquica dos dados capaz de fornecer uma visão geral da gravidade e abrangência do fenômeno.

Algoritmo recocido simulado para el problema de la programación del tamaño del lote económico bajo el enfoque de ciclo básico Simulated annealing algorithm to solve the economic lot scheduling problem and the basic cycle approach

Directory of Open Access Journals (Sweden)

José Omar Hernández

2011-12-01

Full Text Available La programación del tamaño del lote económico consiste en determinar la secuencia y la cantidad a fabricar de N productos en un equipo o máquina, la cual tiene una capacidad limitada. Se trata de un problema NP-duro y las propuestas de solución son diversas. En esta investigación se trabaja con el enfoque del ciclo básico planteado por Bomberger, para el cual existen varias propuestas, dentro de las cuales se pueden encontrar hasta el momento sólo algoritmos genéticos en lo que se refiere a la implementación de técnicas metaheurísticas para resolver el problema. En este trabajo se resuelve el problema de muestra de Bomberger mediante la metaheurística recocido simulado; las aportaciones de esta investigación consisten en la forma de obtener un espacio de búsqueda más restringido de las variables, y una estrategia para controlar la exploración del espacio de soluciones que realiza el algoritmo, de tal manera que se realice una búsqueda eficiente. Dado que es una primera implementación de recocido simulado se experimenta con varias combinaciones de parámetros. El algoritmo obtiene los mismos costos en casi todas las pruebas realizadas; sin embargo, en las pruebas donde la relación es alta, el algoritmo se desempeña mejor, mejorando la solución reportada anteriormente en algunos de los experimentos.The problem considered is that of scheduling the production of several different items over the same machine with restricted capacity and on a repetitive basis. The problem is NP-hard and there exist several methods for the problem. In this research we worked with Bomberger's basic cycle approach, for which there are reported several solution proposals, among which are found so far only genetic algorithms in regard to the implementation of metaheuristic techniques to solve the problem. We solved Bomberger's classical example problem, applying simulated annealing metaheuristic. The contributions of this research consist on how to

A intensidade dos algoritmos nas séries iniciais: uma imposição sócio-histórico-estrutural ou opção valiosa? p.55-76

OpenAIRE

Mendonça, Maria do Carmo Domite

2009-01-01

Como nós professores podemos reconhecer/valorizar ou não o quadro que aí está em Educação Matemática? Como os professores-pesquisadores podemos compreender a ansiedade existente em treinar os algoritmos convencionais, quando o assunto é o cálculo das operações aritméticas básicas? Um caminho para a mudança seria focalizar/discutir o que, naturalmente, tem bloqueado atitudes de maior autonomia frente a esse fato matemático, imobilizando-os mesmo para qualquer inovação. Então, usando argumentos...

Pd/C Synthesized with Citric Acid: An Efficient Catalyst for Hydrogen Generation from Formic Acid/Sodium Formate

Science.gov (United States)

Wang, Zhi-Li; Yan, Jun-Min; Wang, Hong-Li; Ping, Yun; Jiang, Qing

2012-01-01

A highly efficient hydrogen generation from formic acid/sodium formate aqueous solution catalyzed by in situ synthesized Pd/C with citric acid has been successfully achieved at room temperature. Interestingly, the presence of citric acid during the formation and growth of the Pd nanoparticles on carbon can drastically enhance the catalytic property of the resulted Pd/C, on which the conversion and turnover frequency for decomposition of formic acid/sodium formate system can reach the highest values ever reported of 85% within 160 min and 64 mol H2 mol−1 catalyst h−1, respectively, at room temperature. The present simple, low cost, but highly efficient CO-free hydrogen generation system at room temperature is believed to greatly promote the practical application of formic acid system on fuel cells. PMID:22953041

Efficiency of small wind generator powered water pumping systems; Rendimento de unidade de bombeamento de agua acionada por gerador eolico de pequeno porte

Energy Technology Data Exchange (ETDEWEB)

Ferreira, Mendeleyev Guerreiro; Carvalho, Paulo Cesar Marques de; Costa, Levy Ferreira [Universidade Federal do Ceara (UFC), Fortaleza, CE (Brazil). Dept. de Engenharia Eletrica; Borges Neto, Manuel Rangel [Centro Federal de Educacao Tecnologica de Petrolina (CEFET), PE (Brazil)

2008-07-01

The present paper aims to evaluate the efficiency of a small wind generator powered water pumping system; the generator is a permanent magnet generator of 1 kw of axial flow, using three fiber glass blades with 2.46 m diameter. The used centrifugal pump is connected to a 0.5 c v motor, three-phase, frequency of 60 Hz, rotational speed of 3450 rpm. For the efficiency evaluation a shell anemometer, a flow and pressure sensor were used, connected to a data logger to the collection and storage of the data. An energy analyzer was also used to collect the current, voltage and power generated from the wind generator. (author)

Combustion efficiency: Greenhouse gas emission reductions from the power generation sector

Energy Technology Data Exchange (ETDEWEB)

Kane, R.; South, D.W.; Fish, A.L. [Argonne National Laboratory, Upton, IL (United States)

1993-12-31

Concern for the possibility of an enhanced greenhouse effect and global climate change (GCC) has often been associated with energy use in general, and fossil fuel combustion in particular, because of associated emissions of CO{sub 2} and other greenhouse gases (GHG). Therefore, energy policies play a significant role in determining greenhouse gas emissions. The generation of electricity and power from more efficient fossil energy technologies provides an opportunity to significantly lower GHG emissions, together with other pollutants. The U.S. government oversees a broad-based program to facilitate the development, demonstration, and deployment of these technologies. Advanced fossil technologies offer other benefits as well, in that they permit continued use of widely available fuels such as coal. An international perspective is critical for assessing the role of these fuels, since countries differ in terms of their ability to maximize these benefits. Often, new technologies are considered the domain of industrialized countries. Yet more efficient technologies may have their greatest potential - to concurrently permit the utilization of indigenous fuels and to lower global GHG emissions in developing countries, especially those in the Asia-Pacific region.

Generating Efficient Femtosecond Mid-infrared Pulse by Single Near-infrared Pump Wavelength in Bulk Nonlinear Crystal Without Phase-matching

DEFF Research Database (Denmark)

Zhou, Binbin; Guo, Hairun; Bache, Morten

2014-01-01

We experimentally demonstrate efficient mid-infrared pulse generation by dispersive wave radiation in bulk lithium niobate crystal. Femtosecond mid-IR pulses centering from 2.8-2.92 μm are generated using the single pump wavelengths from 1.25-1.45 μm. © 2014 Optical Society of America...

Claves en la aplicación del algoritmo Chaid. Un estudio del ocio físico deportivo universitario

Directory of Open Access Journals (Sweden)

Eva Sanz Arazuri

2010-01-01

Full Text Available El propósito de este artículo es argumentar y explicar la utilidad y el procedimiento de la segmentación jerárquica basada en el algoritmo CHAID como técnica de análisis multivariado. Para facilitar la comprensión de este proceso, la exposición del uso, así como, la interpretación de esta técnica nos hemos servido de una investigación realizada sobre el comportamiento físico-deportivo de tiempo libre de una población universitaria. Este estudio busca definir los perfiles de los universitarios en función de los distintos grados de satisfacción con su práctica físico-deportiva, así como, constatar la existencia de determinadas variables predictoras de dicha satisfacción al relacionar globalmente todas. En el artículo queda demostrada la valiosa capacidad que posee esta técnica de segmentación jerárquica para pronosticar y explicar determinados comportamientos, así como para determinar la relación causa-efecto de dichos comportamientos.

Chloride ion-catalyzed generation of difluorocarbene for efficient preparation of gem-difluorinated cyclopropenes and cyclopropanes

KAUST Repository

Wang, Fei; Zhang, Wei; Zhu, Jieming; Li, Huaifeng; Huang, Kuo-Wei; Hu, Jinbo

2011-01-01

A chloride ion-catalyzed generation of difluorocarbene from a relatively non-toxic and inexpensive precursor, Me3SiCF2Cl (1), under mild and neutral conditions leads to an efficient preparation of gem-difluorocyclopropenes and difluorocyclopropanes through [2 + 1] cycloaddition reactions with alkynes and alkenes, respectively. © 2011 The Royal Society of Chemistry.

Estimación de la temperatura superficial del mar desde datos satelitales NOAA-AVHRR: validación de algoritmos aplicados a la costa norte de Chile Sea surface temperature estimation from NOAA-AVHRR satellite data: validation of algorithms applied to the northern coast of Chile

Directory of Open Access Journals (Sweden)

Juan C Parra

2011-01-01

Full Text Available Se aplicaron y compararon tres algoritmos del tipo Split-Window (SW, que permitieron estimar la temperatura superficial del mar desde datos aportados por el sensor Advanced Very High Resolution Radiometer (AVHRR, a bordo de la serie de satélites de la National Oceanic and Atmospheric Administration (NOAA. La validación de los algoritmos fue lograda por comparación con mediciones in situ de temperatura del mar provenientes de una boya hidrográfica, ubicada frente a la costa norte de Chile (21°21'S, 70°6'W; Región de Tarapacá, a 3 km de la costa aproximadamente. Los mejores resultados se obtuvieron por aplicación del algoritmo propuesto por Sobrino & Raissouni (2000. En efecto, diferencias entre la temperatura medida in situ y la estimada por SW, permitieron evidenciar una media y desviación estándar de 0,3° y 0,8°K, respectivamente.The present article applies and compares three split-window (SW algorithms, which allowed the estimation of sea surface temperature using data obtained from the Advanced Very High Resolution Radiometer (AVHRR on board the National Oceanic and Atmospheric Administration (NOAA series of satellites. The algorithms were validated by comparison with in situ measurements of sea temperature obtained from a hydrographical buoy located off the coast of northern Chile (21°21'S, 70°6'W; Tarapacá Región, approximately 3 km from the coast. The best results were obtained by the application of the algorithm proposed by Sobrino & Raissouni (2000. The mean and standard deviation of the differences between the temperatures measured in situ and those estimated by SW were 0.3° and 0.8°K, respectively.

More efficient second harmonic generation of whispering gallery modes by selective out-coupling

OpenAIRE

Trainor, Luke S.; Sedlmeir, Florian; Peuntinger, Christian; Schwefel, Harald G. L.

2017-01-01

We demonstrate second harmonic generation (SHG) in an $x$-cut congruent lithium niobate (LN) whispering gallery mode resonator. We first show theoretically that independent control of the coupling of the pump and signal modes is optimal for high conversion rates. A scheme based on our earlier work in Ref. [1] is then implemented experimentally to verify this. Thereby we are able to improve on the efficiency of SHG by more than an order of magnitude by selectively out-coupling using a LN prism...

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

Science.gov (United States)

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the "punctum fixum-punctum mobile model" that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of context

The punctum fixum-punctum mobile model: a neuromuscular principle for efficient movement generation?

Directory of Open Access Journals (Sweden)

Christoph von Laßberg

Full Text Available According to the "punctum fixum-punctum mobile model" that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum toward the body part that shall be accelerated (punctum mobile. The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline, as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]. The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning

The Punctum Fixum-Punctum Mobile Model: A Neuromuscular Principle for Efficient Movement Generation?

Science.gov (United States)

von Laßberg, Christoph; Rapp, Walter

2015-01-01

According to the “punctum fixum–punctum mobile model” that was introduced in prior studies, for generation of the most effective intentional acceleration of a body part the intersegmental neuromuscular onset succession has to spread successively from the rotation axis (punctum fixum) toward the body part that shall be accelerated (punctum mobile). The aim of the present study was to investigate whether this principle is, indeed, fundamental for any kind of efficient rotational accelerations in general, independent of the kind of movements, type of rotational axis, the current body position, or movement direction. Neuromuscular onset succession was captured by surface electromyography of relevant muscles of the anterior and posterior muscle chain in 16 high-level gymnasts during intentional accelerating movement phases while performing 18 different gymnastics elements (in various body positions to forward and backward, performed on high bar, parallel bars, rings and trampoline), as well as during non-sport specific pivot movements around the longitudinal axis. The succession patterns to generate the acceleration phases during these movements were described and statistically evaluated based on the onset time difference between the muscles of the corresponding muscle chain. In all the analyzed movement phases, the results clearly support the hypothesized succession pattern from punctum fixum to punctum mobile. This principle was further underlined by the finding that the succession patterns do change their direction running through the body when the rotational axis (punctum fixum) has been changed (e.g., high bar or rings [hands] vs. floor or trampoline [feet]). The findings improve our understanding of intersegmental neuromuscular coordination patterns to generate intentional movements most efficiently. This could help to develop more specific methods to facilitate such patterns in particular contexts, thus allowing for shorter motor learning procedures of

Achieving 100% Efficient Postcolumn Hydride Generation for As Speciation Analysis by Atomic Fluorescence Spectrometry.

Science.gov (United States)

Marschner, Karel; Musil, Stanislav; Dědina, Jiří

2016-04-05

An experimental setup consisting of a flow injection hydride generator coupled to an atomic fluorescence spectrometer was optimized in order to generate arsanes from tri- and pentavalent inorganic arsenic species (iAs(III), iAs(V)), monomethylarsonic acid (MAs(V)), and dimethylarsinic acid (DMAs(V)) with 100% efficiency with the use of only HCl and NaBH4 as the reagents. The optimal concentration of HCl was 2 mol L(-1); the optimal concentration of NaBH4 was 2.5% (m/v), and the volume of the reaction coil was 8.9 mL. To prevent excessive signal noise due to fluctuations of hydride supply to an atomizer, a new design of a gas-liquid separator was implemented. The optimized experimental setup was subsequently interfaced to HPLC and employed for speciation analysis of arsenic. Two chromatography columns were tested: (i) ion-pair chromatography and (ii) ion exchange chromatography. The latter offered much better results for human urine samples without a need for sample dilution. Due to the equal hydride generation efficiency (and thus the sensitivities) of all As species, a single species standardization by DMAs(V) standard was feasible. The limits of detection for iAs(III), iAs(V), MAs(V), and DMAs(V) were 40, 97, 57, and 55 pg mL(-1), respectively. Accuracy of the method was tested by the analysis of the standard reference material (human urine NIST 2669), and the method was also verified by the comparative analyses of human urine samples collected from five individuals with an independent reference method.

Copper vapour laser with an efficient semiconductor pump generator having comparable pump pulse and output pulse durations

Energy Technology Data Exchange (ETDEWEB)

Yurkin, A A [P N Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

2016-03-31

We report the results of experimental studies of a copper vapour laser with a semiconductor pump generator capable of forming virtually optimal pump pulses with a current rise steepness of about 40 A ns{sup -1} in a KULON LT-1.5CU active element. To maintain the operating temperature of the active element's channel, an additional heating pulsed oscillator is used. High efficiency of the pump generator is demonstrated. (lasers)

Notes on 'Hit-And-Run enables efficient weight generation for simulation-based multiple criteria decision analysis'

NARCIS (Netherlands)

van Valkenhoef, Gert; Tervonen, Tommi; Postmus, Douwe

2014-01-01

In our previous work published in this journal, we showed how the Hit-And-Run (HAR) procedure enables efficient sampling of criteria weights from a space formed by restricting a simplex with arbitrary linear inequality constraints. In this short communication, we note that the method for generating

Efficient and Cost-Effective Generation of Mature Neurons From Human Induced Pluripotent Stem Cells

OpenAIRE

Badja , Cherif; Maleeva , Galyna; El-Yazidi , Claire; Barruet , Emilie; Lasserre , Manon; Tropel , Philippe; Binetruy , Bernard; Bregestovski , Piotr; Magdinier , Frédérique

2014-01-01

The authors describe a feeder-free method of generating induced pluripotent stem cells by relying on the use of a chemically defined medium that overcomes the need for embryoid body formation and neuronal rosette isolation for neuronal precursors and terminally differentiated neuron production. This specific and efficient single-step strategy allows the production of mature neurons in 20–40 days with multiple applications, especially for modeling human pathologies.

EFFECT OF GAMMA RADIATION OF MACRO MUTATIONS, EFFECTIVENESS AND EFFICIENCY UNDER M2 GENERATION IN PEA (Pisum sativum L.

Directory of Open Access Journals (Sweden)

Arvind KUMAR

2016-06-01

Full Text Available The present investigation was undertaken to study the spectrum of macro mutants, effectiveness and efficiency of different doses of gamma rays in pea variety (Arkel. The seeds were treated with gamma rays viz., 00kR (dry control, 05kR, 10kR, 15kR, 20kR, 25kR, 30kR, 35kR, 40kR (dry seeds and presoaked seeds of the same was exposed to 00kR (wet control, 05kR, 10kR, 15kR, 20kR (kilo Roentgen biological damage was calculated in M1 and M2 generation based on lethality (L and pollen sterility. The irradiated seeds were sown in the M1 field their respective controls and harvested in bulk to raise the M2 generation in Randomized Block Design (RBD with three replications. The spectrum of macro mutants i.e., plant stature (tall, dwarf, small dwarf, maturity (early, late, pod shape (bold, long, short, seed colour (brown, light white, light green and seed shape (small, bold, wrinkled were observed in M2 generation. The usefulness of any mutagen in plant breeding depends not only on its effectiveness but also upon if efficiency. Mutagenic effectiveness is a measure of the frequency of mutations induced by unit mutagen dose, whereas mutagenic efficiency is measure of proportion of mutations in relation of undesirable changes like lethality and sterility are used for gamma rays. A result of the indicated positive relationship in M2 generation with macro mutation, effectiveness and efficiency was found to be highest at lowest doses.

Comparison of elution efficiency of 99Mo/99mTc generator using theoretical and a free web based software method

International Nuclear Information System (INIS)

Kiran Kumar, J.K.; Sharma, S.; Chakraborty, D.; Singh, B.; Bhattacharaya, A.; Mittal, B.R.; Gayana, S.

2010-01-01

Full text: Generator is constructed on the principle of decay growth relationship between a long lived parent radionuclide and short lived daughter radionuclide. Difference in chemical properties of daughter and parent radionuclide helps in efficient separation of the two radionuclides. Aim and Objectives: The present study was designed to calculate the elution efficiency of the generator using the traditional formula based method and free web based software method. Materials and Methods: 99 Mo/ 99m Tc MON.TEK (Monrol, Gebze) generator and sterile 0.9% NaCl vial and vacuum vial in the lead shield were used for the elution. A new 99 Mo/ 99m Tc generator (calibrated activity 30GBq) calibrated for thursday was received on monday morning in our department. Generator was placed behind lead bricks in fume hood. The rubber plugs of both vacuum and 0.9% NaCl vial were wiped with 70% isopropyl alcohol swabs. Vacuum vial placed inside the lead shield was inserted in the vacuum position simultaneously 10 ml NaCl vial was inserted in the second slot. After 1-2 min vacuum vial was removed without moving the emptied 0.9%NaCl vial. The vacuum slot was covered with another sterile vial to maintain sterility. The RAC was measured in the calibrated dose calibrator (Capintec, 15 CRC). The elution efficiency was calculated theoretically and using free web based software (Apache Web server (www.apache.org) and PHP (www.php.net). Web site of the Italian Association of Nuclear Medicine and Molecular Imaging (www.aimn.it). Results: The mean elution efficiency calculated by theoretical method was 93.95% +0.61. The mean elution efficiency as calculated by the software was 92.85% + 0.89. There was no statistical difference in both the methods. Conclusion: The free web based software provides precise and reproducible results and thus saves time and mathematical calculation steps. This enables a rational use of available activity and also enabling a selection of the type and number of

Development of a Handheld Line Information Reader and Generator for Efficient Management of Optical Communication Lines.

Science.gov (United States)

Lee, Jaeyul; Kwon, Hyungwoo; Song, Jaewon; Jeon, Mansik; Kim, Jeehyun

2017-08-24

A handheld line information reader and a line information generator were developed for the efficient management of optical communication lines. The line information reader consists of a photo diode, trans-impedance amplifier, voltage amplifier, microcontroller unit, display panel, and communication modules. The line information generator consists of a laser diode, laser driving circuits, microcontroller unit, and communication modules. The line information reader can detect the optical radiation field of the test line by bending the optical fiber. To enhance the sensitivity of the line information reader, an additional lens was used with a focal length of 4.51 mm. Moreover, the simulation results obtained through BeamPROP ® software from Synopsys, Inc. demonstrated a stronger optical radiation field of the fiber due to a longer transmission wavelength and larger bending angle of the fiber. Therefore, the developed devices can be considered as useful tools for the efficient management of optical communication lines.

Efficiency of different methods of extra-cavity second harmonic generation of continuous wave single-frequency radiation.

Science.gov (United States)

Khripunov, Sergey; Kobtsev, Sergey; Radnatarov, Daba

2016-01-20

This work presents for the first time to the best of our knowledge a comparative efficiency analysis among various techniques of extra-cavity second harmonic generation (SHG) of continuous-wave single-frequency radiation in nonperiodically poled nonlinear crystals within a broad range of power levels. Efficiency of nonlinear radiation transformation at powers from 1 W to 10 kW was studied in three different configurations: with an external power-enhancement cavity and without the cavity in the case of single and double radiation pass through a nonlinear crystal. It is demonstrated that at power levels exceeding 1 kW, the efficiencies of methods with and without external power-enhancement cavities become comparable, whereas at even higher powers, SHG by a single or double pass through a nonlinear crystal becomes preferable because of the relatively high efficiency of nonlinear transformation and fairly simple implementation.

Efficiency and entropy generation in fined tube solar collectors systems; Eficiencia e geracao de entropia em sistemas de tubos aletados coletores de energia solar

Energy Technology Data Exchange (ETDEWEB)

Santos, Marcio Bueno dos [Instituto Nacional de Pesquisas Espaciais (INPE), Sao Jose dos Campos, SP (Brazil). Lab. de Integracao e Testes; Saboya, Sergio Mourao [Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, SP (Brazil). Dept. de Energia

1998-07-01

This paper studies the efficiency of a fined tube solar collector used in artificial satellites and the relation of this efficiency with the entropy generation in the fin. The mathematical modeling of heat transfer in the collector leads to a non-linear integrodifferential system of equations, which is solved numerically. The solution gives the efficiency, which is presented as function of geometrical and physical characteristics of the collector. It is also shown that a minimum entropy generation in the fins, in a collector, whose characteristics are subjected to constraints, corresponds to an optimum efficiency, that is, an efficiency value advantageous to collector performance. (author)

Valoración epidemiológica de la linfadenitis tuberculosa en un distrito de Barcelona: propuesta de algoritmo diagnóstico

Directory of Open Access Journals (Sweden)

Silvia Aguilar-Duran

2014-01-01

Full Text Available Fundamentos: Barcelona ha experimentado un cambio en su demografía que ha afectado la epidemiología local de la linfadenitis tuberculosa (LT. El objetivo del estudio es conocer los factores actualmente asociados a LT en un distrito de Barcelona con una incidencia media de TB superior a 50 casos por 10.000 habitantes/año así como plantear un algoritmo diagnóstico. Métodos: estudio de cohortes retrospectivo de todos los casos de LT diagnosticados entre 1990 y 2009 en el Hospital del Mar de Barcelona. De acuerdo a los cambios demográficos, se establecieron dos periodos de estudio (1990-1999 y 2000-2009 y se analizaron y compararon las características sociodemográficas, clínicas y diagnósticas de los sujetos con LT para la posterior realización del algoritmo. La información se obtuvo de las encuestas epidemiológicas realizadas a los pacientes diagnosticados de LT en el Hospital del Mar y notificadas a la Agència de Salut Pública de Barcelona. Resultados: en el primer periodo, 152 pacientes presentaron LT (siendo 73,7% autóctonos y en el segundo 147 (siendo 70,7% inmigrantes. En el primer periodo, el porcentaje de hombres immigrantes fue del 70,5% y 57,1% menores de 35 años, aunque en el segundo periodo se observó en autóctonos e l 58,1% de mujeres y 69,8% mayores de 35 años. El porcentaje de pacientes autóctonos con VIH disminuyó de 66,9% a 44,2% en el segundo periodo y hubo aumento de pacientes en tratamiento inmunosupresor (9,3%. El análisis multivariante dio como resultado (OR 8,2;IC 95% 3,4-19,8 para el uso de drogas intravenosas y OR 4,8 (IC95% 2,7-8,3para la inmigración como factores de riesgo a LT. Conclusiones: los varones inmigrantes menores de 35 años procedentes de zonas endémicas de tuberculosis y los autóctonos mayores de 35 años con VIH (aunque con un menor porcentaje de coinfección que antes del año 2000 o en tratamiento inmunosupresor son los grupos con más riesgo de presentar LT en nuestro distrito.

Analysis of the efficiency and effectiveness of distributed generation in the power station (fuel) Sancti Spiritus

International Nuclear Information System (INIS)

Castro Álvarez, Alfredo; Pérez Pérez, Osvaldo; Bravo Amarante, Edelvy

2015-01-01

The severe crisis in the National Electric System (SEN) suffered by Cuba in the late 90's and early 2000 forced to change the design to keep the generation matrix supported in large plants towards where distributed generation small plants throughout the country, the state assumed demand and residential sector. From tools frequently used to evaluate the quality of processes (Scatter diagram, Pareto diagram, Ishikawa diagram and function quality loss Taguchi) was evaluated from indicators index fuel consumption and availability, efficiency and effectiveness of the generation process identifying areas within the plant that the greatest impact on the deviation of both indicators and the impact generated in the services, the economy and the environment. To develop this evaluation the operating data of the years 2012, 2013 and 2014 of the power plant were taken Sancti Spiritus. (full text)

Electrical efficiency and renewable energy - Economical alternatives to large-scale power generation

International Nuclear Information System (INIS)

Oettli, B.; Hammer, S.; Moret, F.; Iten, R.; Nordmann, T.

2010-05-01

This final report for WWF Switzerland, Greenpeace Switzerland, the Swiss Energy Foundation SES, Pro Natura and the Swiss Cantons of Basel City and Geneva takes a look at the energy-relevant effects of the propositions made by Swiss electricity utilities for large-scale power generation. These proposals are compared with a strategy that proposes investments in energy-efficiency and the use of renewable sources of energy. The effects of both scenarios on the environment and the risks involved are discussed, as are the investments involved. The associated effects on the Swiss national economy are also discussed. For the efficiency and renewables scenario, two implementation variants are discussed: Inland investments and production are examined as are foreign production options and/or import from foreign countries. The methods used in the study are introduced and discussed. Investment and cost considerations, earnings and effects on employment are also reviewed. The report is completed with an extensive appendix which, amongst other things, includes potential reviews, cost estimates and a discussion on 'smart grids'

High efficiency H6 single-phase transformerless grid-tied PV inverter with proposed modulation for reactive power generation

Science.gov (United States)

Almasoudi, Fahad M.; Alatawi, Khaled S.; Matin, Mohammad

2017-08-01

Implementation of transformerless inverters in PV grid-tied system offer great benefits such as high efficiency, light weight, low cost, etc. Most of the proposed transformerless inverters in literature are verified for only real power application. Currently, international standards such as VDE-AR-N 4105 has demanded that PV grid-tied inverters should have the ability of controlling a specific amount of reactive power. Generation of reactive power cannot be accomplished in single phase transformerless inverter topologies because the existing modulation techniques are not adopted for a freewheeling path in the negative power region. This paper enhances a previous high efficiency proposed H6 trnasformerless inverter with SiC MOSFETs and demonstrates new operating modes for the generation of reactive power. A proposed pulse width modulation (PWM) technique is applied to achieve bidirectional current flow through freewheeling state. A comparison of the proposed H6 transformerless inverter using SiC MOSFETs and Si MOSFTEs is presented in terms of power losses and efficiency. The results show that reactive power control is attained without adding any additional active devices or modification to the inverter structure. Also, the proposed modulation maintains a constant common mode voltage (CM) during every operating mode and has low leakage current. The performance of the proposed system verifies its effectiveness in the next generation PV system.

Thermodynamic, energy efficiency, and power density analysis of reverse electrodialysis power generation with natural salinity gradients.

Science.gov (United States)

Yip, Ngai Yin; Vermaas, David A; Nijmeijer, Kitty; Elimelech, Menachem

2014-05-06

Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable power generation. In this study, we carry out a thermodynamic and energy efficiency analysis of RED power generation, and assess the membrane power density. First, we present a reversible thermodynamic model for RED and verify that the theoretical maximum extractable work in a reversible RED process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible process with maximized power density using a constant-resistance load is then examined to assess the energy conversion efficiency and power density. With equal volumes of seawater and river water, energy conversion efficiency of ∼ 33-44% can be obtained in RED, while the rest is lost through dissipation in the internal resistance of the ion-exchange membrane stack. We show that imperfections in the selectivity of typical ion exchange membranes (namely, co-ion transport, osmosis, and electro-osmosis) can detrimentally lower efficiency by up to 26%, with co-ion leakage being the dominant effect. Further inspection of the power density profile during RED revealed inherent ineffectiveness toward the end of the process. By judicious early discontinuation of the controlled mixing process, the overall power density performance can be considerably enhanced by up to 7-fold, without significant compromise to the energy efficiency. Additionally, membrane resistance was found to be an important factor in determining the power densities attainable. Lastly, the performance of an RED stack was examined for different membrane conductivities and intermembrane distances simulating high performance membranes and stack design. By thoughtful selection of the operating parameters, an efficiency of ∼ 37% and an overall gross power density of 3.5 W/m(2) represent the maximum performance that can potentially be achieved in a seawater-river water RED system with low

The impact of liberalization on the scope of efficiency improvement in electricity-generating portfolios for the United States and Switzerland

Energy Technology Data Exchange (ETDEWEB)

Krey, B.; Zweifel, P. [Socioeconomic Institute, Zurich (Switzerland)

2008-09-15

In this study, Markowitz mean-variance portfolio theory is applied to electricity-generating technologies of the United States and Switzerland. Both an investor (focused on changes in return) and a current user (focused on return in levels) view are adopted to determine efficient frontiers of electricity generation technologies in terms of expected return and risk as of 2003. Since shocks in generation costs per kWh (the inverse of returns) are correlated, Seemingly Unrelated Regression Estimation (SURE) is used to filter out the systematic components of the covariance matrix. Results suggest that risk-averse investors and risk-neutral current users in the United States are considerably closer to their efficiency frontier than their Swiss counterparts. This may be due to earlier and more thorough deregulation of electricity markets in the United States. (orig.)

An efficient plant viral expression system generating orally immunogenic Norwalk virus-like particles.

Science.gov (United States)

Santi, Luca; Batchelor, Lance; Huang, Zhong; Hjelm, Brooke; Kilbourne, Jacquelyn; Arntzen, Charles J; Chen, Qiang; Mason, Hugh S

2008-03-28

Virus-like particles (VLPs) derived from enteric pathogens like Norwalk virus (NV) are well suited to study oral immunization. We previously described stable transgenic plants that accumulate recombinant NV-like particles (rNVs) that were orally immunogenic in mice and humans. The transgenic approach suffers from long generation time and modest level of antigen accumulation. We now overcome these constraints with an efficient tobacco mosaic virus (TMV)-derived transient expression system using leaves of Nicotiana benthamiana. We produced properly assembled rNV at 0.8 mg/g leaf 12 days post-infection (dpi). Oral immunization of CD1 mice with 100 or 250 microg/dose of partially purified rNV elicited systemic and mucosal immune responses. We conclude that the plant viral transient expression system provides a robust research tool to generate abundant quantities of rNV as enriched, concentrated VLP preparations that are orally immunogenic.

PVT: an efficient computational procedure to speed up next-generation sequence analysis.

Science.gov (United States)

Maji, Ranjan Kumar; Sarkar, Arijita; Khatua, Sunirmal; Dasgupta, Subhasis; Ghosh, Zhumur

2014-06-04

High-throughput Next-Generation Sequencing (NGS) techniques are advancing genomics and molecular biology research. This technology generates substantially large data which puts up a major challenge to the scientists for an efficient, cost and time effective solution to analyse such data. Further, for the different types of NGS data, there are certain common challenging steps involved in analysing those data. Spliced alignment is one such fundamental step in NGS data analysis which is extremely computational intensive as well as time consuming. There exists serious problem even with the most widely used spliced alignment tools. TopHat is one such widely used spliced alignment tools which although supports multithreading, does not efficiently utilize computational resources in terms of CPU utilization and memory. Here we have introduced PVT (Pipelined Version of TopHat) where we take up a modular approach by breaking TopHat's serial execution into a pipeline of multiple stages, thereby increasing the degree of parallelization and computational resource utilization. Thus we address the discrepancies in TopHat so as to analyze large NGS data efficiently. We analysed the SRA dataset (SRX026839 and SRX026838) consisting of single end reads and SRA data SRR1027730 consisting of paired-end reads. We used TopHat v2.0.8 to analyse these datasets and noted the CPU usage, memory footprint and execution time during spliced alignment. With this basic information, we designed PVT, a pipelined version of TopHat that removes the redundant computational steps during 'spliced alignment' and breaks the job into a pipeline of multiple stages (each comprising of different step(s)) to improve its resource utilization, thus reducing the execution time. PVT provides an improvement over TopHat for spliced alignment of NGS data analysis. PVT thus resulted in the reduction of the execution time to ~23% for the single end read dataset. Further, PVT designed for paired end reads showed an

Training the next generation of energy efficiency evaluators

Energy Technology Data Exchange (ETDEWEB)

Vine, E. [Lawrence Berkeley National Laboratory LBNL and California Institute for Energy and Environment, Berkeley, CA (United States); Saxonis, W. [New York Department of Public Service, Albany, NY (United States); Peters, J. [Research Into Action, Portland, OR (United States); Tannenbaum, B. [Research Into Action, Madison, WI (United States); Wirtshafter, B. [Wirstshafter Associates, Rydal, PA (United States)

2013-05-15

The energy efficiency services sector is an increasingly important part of the global economy, with an increased need for trained evaluators to foster energy efficiency program accountability and improvement. Organizations are experiencing difficulty in finding people who are knowledgeable about and experienced in the evaluation of energy efficiency programs. Accordingly, there is a need to assess the training needs of the energy efficiency evaluation community (for both new and 'experienced' evaluators). This paper presents the results of a recent survey conducted by the International Energy Program Evaluation Conference (IEPEC) on energy efficiency evaluation training needs and contrasts those findings with the findings from a survey conducted by the American Evaluation Association on young evaluators (those people in the field <5 years) and another by the Association of Energy Services Professionals. This analysis is also complemented by a brief survey of members of the 2012 Rome Conference IEPEC Planning Committee on international needs.

Cost efficiency of Japanese steam power generation companies: A Bayesian comparison of random and fixed frontier models

Energy Technology Data Exchange (ETDEWEB)

Assaf, A. George [Isenberg School of Management, University of Massachusetts-Amherst, 90 Campus Center Way, Amherst 01002 (United States); Barros, Carlos Pestana [Instituto Superior de Economia e Gestao, Technical University of Lisbon, Rua Miguel Lupi, 20, 1249-078 Lisbon (Portugal); Managi, Shunsuke [Graduate School of Environmental Studies, Tohoku University, 6-6-20 Aramaki-Aza Aoba, Aoba-Ku, Sendai 980-8579 (Japan)

2011-04-15

This study analyses and compares the cost efficiency of Japanese steam power generation companies using the fixed and random Bayesian frontier models. We show that it is essential to account for heterogeneity in modelling the performance of energy companies. Results from the model estimation also indicate that restricting CO{sub 2} emissions can lead to a decrease in total cost. The study finally discusses the efficiency variations between the energy companies under analysis, and elaborates on the managerial and policy implications of the results. (author)

Second Generation Advanced Reburning for High Efficiency NOx Control

International Nuclear Information System (INIS)

Zamansky, Vladimir M.; Maly, Peter M.; Sheldon, Mark; Seeker, W. Randall; Folsom, Blair A.

1997-01-01

Energy and Environmental Research Corporation is developing a family of high efficiency and low cost NO x control technologies for coal fired utility boilers based on Advanced Reburning (AR), a synergistic integration of basic reburning with injection of an N-agent. In conventional AR, injection of the reburn fuel is followed by simultaneous N-agent and overfire air injection. The second generation AR systems incorporate several components which can be used in different combinations. These components include: (1) Reburning Injection of the reburn fuel and overfire air. (2) N-agent Injection The N-agent (ammonia or urea) can be injected at different locations: into the reburning zone, along with the overfire air, and downstream of the overfire air injection. (3) N-agent Promotion Several sodium compounds can considerably enhance the NO x control from N-agent injection. These ''promoters'' can be added to aqueous N-agents. (4) Two Stages of N-agent Injection and Promotion Two N-agents with or without promoters can be injected at different locations for deeper NO x control. AR systems are intended for post-RACT applications in ozone non-attainment areas where NO x control in excess of 80% is required. AR will provide flexible installations that allow NO x levels to be lowered when regulations become more stringent. The total cost of NO x control for AR systems is approximately half of that for SCR. Experimental and kinetic modeling results for development of these novel AR systems are presented. Tests have been conducted in a 1.0 MMBtu/hr Boiler Simulator Facility with coal as the main fuel and natural gas as the reburning fuel. The results show that high efficiency NO x control, in the range 84-95%, can be achieved with various elements of AR. A comparative byproduct emission study was performed to compare the emissions from different variants of AR with commercial technologies (reburning and SNCR). For each technology sampling included: CO, SO 2 , N 2 O, total

An efficient Agrobacterium-mediated transformation method for aflatoxin generation fungus Aspergillus flavus.

Science.gov (United States)

Han, Guomin; Shao, Qian; Li, Cuiping; Zhao, Kai; Jiang, Li; Fan, Jun; Jiang, Haiyang; Tao, Fang

2018-05-01

Aspergillus flavus often invade many important corps and produce harmful aflatoxins both in preharvest and during storage stages. The regulation mechanism of aflatoxin biosynthesis in this fungus has not been well explored mainly due to the lack of an efficient transformation method for constructing a genome-wide gene mutant library. This challenge was resolved in this study, where a reliable and efficient Agrobacterium tumefaciens-mediated transformation (ATMT) protocol for A. flavus NRRL 3357 was established. The results showed that removal of multinucleate conidia, to collect a homogenous sample of uninucleate conidia for use as the transformation material, is the key step in this procedure. A. tumefaciens strain AGL-1 harboring the ble gene for zeocin resistance under the control of the gpdA promoter from A. nidulans is suitable for genetic transformation of this fungus. We successfully generated A. flavus transformants with an efficiency of ∼ 60 positive transformants per 10 6 conidia using our protocol. A small-scale insertional mutant library (∼ 1,000 mutants) was constructed using this method and the resulting several mutants lacked both production of conidia and aflatoxin biosynthesis capacity. Southern blotting analysis demonstrated that the majority of the transformants contained a single T-DNA insert on the genome. To the best of our knowledge, this is the first report of genetic transformation of A. flavus via ATMT and our protocol provides an effective tool for construction of genome-wide gene mutant libraries for functional analysis of important genes in A. flavus.

Efficient third harmonic generation of a CW-fibered 1.5 µm laser diode

Science.gov (United States)

Philippe, Charles; Chea, Erick; Nishida, Yoshiki; du Burck, Frédéric; Acef, Ouali

2016-10-01

We report on frequency tripling of CW-Telecom laser diode using two cascaded PPLN ridge nonlinear crystals, both used in single-pass configuration. All optical components used for this development are fibered, leading to a very compact and easy to use optical setup. We have generated up to 290 mW optical power in the green range, from 800 mW only of infrared power around 1.54 µm. This result corresponds to an optical conversion efficiency P 3 ω / P ω > 36 %. To our knowledge, this is best value ever demonstrated up today for a CW-third harmonic generation in single-pass configuration. This frequency tripling experimental setup was tested over more than 2 years of continuous operation, without any interruption. The compactness and the reliability of our device make it very suitable as a transportable optical oscillator. In particular, it paves the way for embedded applications thanks to the high level of long-term stability of the optical alignments.

Performance tests and efficiency analysis of Solar Invictus 53S - A parabolic dish solar collector for direct steam generation

Science.gov (United States)

Jamil, Umer; Ali, Wajahat

2016-05-01

This paper presents the results of performance tests conducted on Solar Invictus 53S `system'; an economically effective solar steam generation solution designed and developed by ZED Solar Ltd. The system consists of a dual axis tracking parabolic solar dish and bespoke cavity type receiver, which works as a Once Through Solar Steam Generator `OTSSG' mounted at the focal point of the dish. The overall performance and efficiency of the system depends primarily on the optical efficiency of the solar dish and thermal efficiency of the OTSSG. Optical testing performed include `on sun' tests using CCD camera images and `burn plate' testing to evaluate the sunspot for size and quality. The intercept factor was calculated using a colour look-back method to determine the percentage of solar rays focused into the receiver. Solar dish tracking stability tests were carried out at different times of day to account for varying dish elevation angles and positions, movement of the sunspot centroid was recorded and logged using a CCD camera. Finally the overall performance and net solar to steam efficiency of the system was calculated by experimentally measuring the output steam parameters at varying Direct Normal Insolation (DNI) levels at ZED Solar's test facility in Lahore, Pakistan. Thermal losses from OTSSG were calculated using the known optical efficiency and measured changes in output steam enthalpy.

Super-hydrophilic copper sulfide films as light absorbers for efficient solar steam generation under one sun illumination

Science.gov (United States)

Guo, Zhenzhen; Ming, Xin; Wang, Gang; Hou, Baofei; Liu, Xinghang; Mei, Tao; Li, Jinhua; Wang, Jianying; Wang, Xianbao

2018-02-01

Solar steam technology is one of the simplest, most direct and effective ways to harness solar energy through water evaporation. Here, we report the development using super-hydrophilic copper sulfide (CuS) films with double-layer structures as light absorbers for solar steam generation. In the double-layer structure system, a porous mixed cellulose ester (MCE) membrane is used as a supporting layer, which enables water to get into the CuS light absorbers through a capillary action to provide continuous water during solar steam generation. The super-hydrophilic property of the double-layer system (CuS/MCE) leads to a thinner water film close to the air-water interface where the surface temperature is sufficiently high, leading to more efficient evaporation (˜80 ± 2.5%) under one sun illumination. Furthermore, the evaporation efficiencies still keep a steady value after 15 cycles of testing. The super-hydrophilic CuS film is promising for practical application in water purification and evaporation as a light absorption material.

Solar thermoelectric generator

Science.gov (United States)

Toberer, Eric S.; Baranowski, Lauryn L.; Warren, Emily L.

2016-05-03

Solar thermoelectric generators (STEGs) are solid state heat engines that generate electricity from concentrated sunlight. A novel detailed balance model for STEGs is provided and applied to both state-of-the-art and idealized materials. STEGs can produce electricity by using sunlight to heat one side of a thermoelectric generator. While concentrated sunlight can be used to achieve extremely high temperatures (and thus improved generator efficiency), the solar absorber also emits a significant amount of black body radiation. This emitted light is the dominant loss mechanism in these generators. In this invention, we propose a solution to this problem that eliminates virtually all of the emitted black body radiation. This enables solar thermoelectric generators to operate at higher efficiency and achieve said efficient with lower levels of optical concentration. The solution is suitable for both single and dual axis solar thermoelectric generators.

Exploring utility organization electricity generation, residential electricity consumption, and energy efficiency: A climatic approach

International Nuclear Information System (INIS)

Craig, Christopher A.; Feng, Song

2017-01-01

Highlights: • Study examined impact of electricity fuel sources and consumption on emissions. • 97.2% of variability in emissions explained by coal and residential electricity use. • Increasing cooling degree days significantly related to increased electricity use. • Effectiveness of state-level energy efficiency programs showed mixed results. - Abstract: This study examined the impact of electricity generation by fuel source type and electricity consumption on carbon emissions to assess the role of climatic variability and energy efficiency (EE) in the United States. Despite high levels of greenhouse gas emissions, residential electricity consumption continues to increase in the United States and fossil fuels are the primary fuel source of electricity generation. 97.2% of the variability in carbon emissions in the electricity industry was explained by electricity generation from coal and residential electricity consumption. The relationships between residential electricity consumption, short-term climatic variability, long-term climatic trends, short-term reduction in electricity from EE programs, and long-term trends in EE programs was examined. This is the first study of its nature to examine these relationships across the 48 contiguous United States. Inter-year and long-term trends in cooling degree days, or days above a baseline temperature, were the primary climatic drivers of residential electricity consumption. Cooling degree days increased across the majority of the United States during the study period, and shared a positive relationship with residential electricity consumption when findings were significant. The majority of electricity reduction from EE programs was negatively related to residential electricity consumption where findings were significant. However, the trend across the majority of states was a decrease in electricity reduction from EE while residential electricity consumption increased. States that successfully reduced consumption

Optimización en la solución del problema inverso en geofísica usando el algoritmo de entrenamiento supervisado de Levenberg-Marquardt

Directory of Open Access Journals (Sweden)

Figueredo Baez Yaqueline

2002-08-01

Full Text Available

In this work it is introduced a methodology for the supervised training of the Neural Networks, using Levenberg Marquardt's algorithm. This method is applied in gravimetry for the optimization in the convergence at the inverse problem.

En este trabajo se presenta una metodología para el entrenamiento supervisado de redes neuronales, utilizando el algoritmo de Levenberg-Marquardt. Este método se aplica en gravimetría para optimizar la convergencia en el problema de inversión.

Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

International Nuclear Information System (INIS)

Yang, Xin-an; Chi, Miao-bin; Wang, Qing-qing; Zhang, Wang-bing

2015-01-01

Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH 4 ). The presence of 5 mg L −1 Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH 4 ) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L −1 ; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L −1 , 10 mg L −1 and 10 mg L −1 , respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples

Efficient generation of volatile species for cadmium analysis in seafood and rice samples by a modified chemical vapor generation system coupled with atomic fluorescence spectrometry

Energy Technology Data Exchange (ETDEWEB)

Yang, Xin-an, E-mail: 13087641@qq.com; Chi, Miao-bin, E-mail: 1161306667@qq.com; Wang, Qing-qing, E-mail: wangqq8812@163.com; Zhang, Wang-bing, E-mail: ahutwbzh@163.com

2015-04-15

Highlights: • We develop a modified chemical vapor generation method coupled with AFS for the determination of cadmium. • The response of Cd could be increased at least four-fold compared to conventional thiourea and Co(II) system. • A simple mixing sequences experiment is designed to study the reaction mechanism. • The interference of transition metal ions can be easily eliminated by adding DDTC. • The method is successfully applied in seafood samples and rice samples. - Abstract: A vapor generation procedure to determine Cd by atomic fluorescence spectrometry (AFS) has been established. Volatile species of Cd are generated by following reaction of acidified sample containing Fe(II) and L-cysteine (Cys) with sodium tetrahydroborate (NaBH{sub 4}). The presence of 5 mg L{sup −1} Fe(II) and 0.05% m/v Cys improves the efficiency of Cd vapor generation substantially about four-fold compared with conventional thiourea and Co(II) system. Three experiments with different mixing sequences and reaction times are designed to study the reaction mechanism. The results document that the stability of Cd(II)–Cys complexes is better than Cys–THB complexes (THB means NaBH{sub 4}) while the Cys–THB complexes have more contribution to improve the Cd vapor generation efficiency than Cd(II)–Cys complexes. Meanwhile, the adding of Fe(II) can catalyze the Cd vapor generation. Under the optimized conditions, the detection limit of Cd is 0.012 μg L{sup −1}; relative standard deviations vary between 0.8% and 5.5% for replicate measurements of the standard solution. In the presence of 0.01% DDTC, Cu(II), Pb(II) and Zn(II) have no significant influence up to 5 mg L{sup −1}, 10 mg L{sup −1}and 10 mg L{sup −1}, respectively. The accuracy of the method is verified through analysis of the certificated reference materials and the proposed method has been applied in the determination of Cd in seafood and rice samples.

Long-term stable stacked CsPbBr3 quantum dot films for highly efficient white light generation in LEDs.

Science.gov (United States)

Song, Young Hyun; Yoo, Jin Sun; Kang, Bong Kyun; Choi, Seung Hee; Ji, Eun Kyung; Jung, Hyun Suk; Yoon, Dae Ho

2016-12-01

We report highly efficient ethyl cellulose with CsPbBr 3 perovskite QD films for white light generation in LED application. Ethyl cellulose with CsPbBr 3 quantum dots is applied with Sr 2 Si 5 N 8  : Eu 2+ red phosphor on an InGaN blue chip, achieving a highly efficient luminous efficacy of 67.93 lm W -1 under 20 mA current.

Efficient simulation of voxelized phantom in GATE with embedded SimSET multiple photon history generator

Science.gov (United States)

Lin, Hsin-Hon; Chuang, Keh-Shih; Lin, Yi-Hsing; Ni, Yu-Ching; Wu, Jay; Jan, Meei-Ling

2014-10-01

GEANT4 Application for Tomographic Emission (GATE) is a powerful Monte Carlo simulator that combines the advantages of the general-purpose GEANT4 simulation code and the specific software tool implementations dedicated to emission tomography. However, the detailed physical modelling of GEANT4 is highly computationally demanding, especially when tracking particles through voxelized phantoms. To circumvent the relatively slow simulation of voxelized phantoms in GATE, another efficient Monte Carlo code can be used to simulate photon interactions and transport inside a voxelized phantom. The simulation system for emission tomography (SimSET), a dedicated Monte Carlo code for PET/SPECT systems, is well-known for its efficiency in simulation of voxel-based objects. An efficient Monte Carlo workflow integrating GATE and SimSET for simulating pinhole SPECT has been proposed to improve voxelized phantom simulation. Although the workflow achieves a desirable increase in speed, it sacrifices the ability to simulate decaying radioactive sources such as non-pure positron emitters or multiple emission isotopes with complex decay schemes and lacks the modelling of time-dependent processes due to the inherent limitations of the SimSET photon history generator (PHG). Moreover, a large volume of disk storage is needed to store the huge temporal photon history file produced by SimSET that must be transported to GATE. In this work, we developed a multiple photon emission history generator (MPHG) based on SimSET/PHG to support a majority of the medically important positron emitters. We incorporated the new generator codes inside GATE to improve the simulation efficiency of voxelized phantoms in GATE, while eliminating the need for the temporal photon history file. The validation of this new code based on a MicroPET R4 system was conducted for 124I and 18F with mouse-like and rat-like phantoms. Comparison of GATE/MPHG with GATE/GEANT4 indicated there is a slight difference in energy

Analysis of an Increase in the Efficiency of a Spark Ignition Engine Through the Application of an Automotive Thermoelectric Generator

Science.gov (United States)

Merkisz, Jerzy; Fuc, Pawel; Lijewski, Piotr; Ziolkowski, Andrzej; Galant, Marta; Siedlecki, Maciej

2016-08-01

We have analyzed the increase of the overall efficiency of a spark ignition engine through energy recovery following the application of an automotive thermoelectric generator (ATEG) of our own design. The design of the generator was developed following emission investigations during vehicle driving under city traffic conditions. The measurement points were defined by actual operation conditions (engine speed and load), subsequently reproduced on an engine dynamometer. Both the vehicle used in the on-road tests and the engine dynamometer were fit with the same, downsized spark ignition engine (with high effective power-to-displacement ratio). The thermodynamic parameters of the exhaust gases (temperature and exhaust gas mass flow) were measured on the engine testbed, along with the fuel consumption and electric current generated by the thermoelectric modules. On this basis, the power of the ATEG and its impact on overall engine efficiency were determined.

Next Generation Pressurized Oxy-Coal Combustion: High Efficiency and No Flue Gas Recirculation

Energy Technology Data Exchange (ETDEWEB)

Rue, David

2013-09-30

The Gas Technology Institute (GTI) has developed a pressurized oxy-coal fired molten bed boiler (MBB) concept, in which coal and oxygen are fired directly into a bed of molten coal slag through burners located on the bottom of the boiler and fired upward. Circulation of heat by the molten slag eliminates the need for a flue gas recirculation loop and provides excellent heat transfer to steam tubes in the boiler walls. Advantages of the MBB technology over other boilers include higher efficiency (from eliminating flue gas recirculation), a smaller and less expensive boiler, modular design leading to direct scalability, decreased fines carryover and handling costs, smaller exhaust duct size, and smaller emissions control equipment sizes. The objective of this project was to conduct techno-economic analyses and an engineering design of the MBB project and to support this work with thermodynamic analyses and oxy-coal burner testing. Techno-economic analyses of GTI’s pressurized oxy-coal fired MBB technology found that the overall plant with compressed CO2 has an efficiency of 31.6%. This is a significant increase over calculated 29.2% efficiency of first generation oxy-coal plants. Cost of electricity (COE) for the pressurized MBB supercritical steam power plant with CO2 capture and compression was calculated to be 134% of the COE for an air-coal supercritical steam power plant with no CO2 capture. This compares positively with a calculated COE for first generation oxy-coal supercritical steam power plants with CO2 capture and compression of 164%. The COE for the MBB power plant is found to meet the U.S. Department of Energy (DOE) target of 135%, before any plant optimization. The MBB power plant was also determined to be simpler than other oxy-coal power plants with a 17% lower capital cost. No other known combustion technology can produce higher efficiencies or lower COE when CO2 capture and compression are included. A thermodynamic enthalpy and exergy analysis

High efficiency transfer of quantum information and multiparticle entanglement generation in translation-invariant quantum chains

International Nuclear Information System (INIS)

Plenio, Martin B; Semiao, Fernando L

2005-01-01

We demonstrate that a translation-invariant chain of interacting quantum systems can be used for high efficiency transfer of quantum entanglement and the generation of multiparticle entanglement over large distances and between arbitrary sites without the requirement of precise spatial or temporal control. The scheme is largely insensitive to disorder and random coupling strengths in the chain. We discuss harmonic oscillator systems both in the case of arbitrary Gaussian states and in situations when at most one excitation is in the system. The latter case, which we prove to be equivalent to an xy-spin chain, may be used to generate genuine multiparticle entanglement. Such a 'quantum data bus' may prove useful in future solid state architectures for quantum information processing

Efficient Simplification Methods for Generating High Quality LODs of 3D Meshes

Institute of Scientific and Technical Information of China (English)

Muhammad Hussain

2009-01-01

Two simplification algorithms are proposed for automatic decimation of polygonal models, and for generating their LODs. Each algorithm orders vertices according to their priority values and then removes them iteratively. For setting the priority value of each vertex, exploiting normal field of its one-ring neighborhood, we introduce a new measure of geometric fidelity that reflects well the local geometric features of the vertex. After a vertex is selected, using other measures of geometric distortion that are based on normal field deviation and distance measure, it is decided which of the edges incident on the vertex is to be collapsed for removing it. The collapsed edge is substituted with a new vertex whose position is found by minimizing the local quadric error measure. A comparison with the state-of-the-art algorithms reveals that the proposed algorithms are simple to implement, are computationally more efficient, generate LODs with better quality, and preserve salient features even after drastic simplification. The methods are useful for applications such as 3D computer games, virtual reality, where focus is on fast running time, reduced memory overhead, and high quality LODs.

Efficient pseudorandom generators based on the DDH assumption

NARCIS (Netherlands)

Rezaeian Farashahi, R.; Schoenmakers, B.; Sidorenko, A.; Okamoto, T.; Wang, X.

2007-01-01

A family of pseudorandom generators based on the decisional Diffie-Hellman assumption is proposed. The new construction is a modified and generalized version of the Dual Elliptic Curve generator proposed by Barker and Kelsey. Although the original Dual Elliptic Curve generator is shown to be

Figure of merit for evaluation of new generation of concrete efficiency

International Nuclear Information System (INIS)

Anton, V.

1997-01-01

In this work it is formulated a global criterion to assess the efficiency in utilization of new generation concrete based on ettringite additive. This concrete is chemically reinforced and has an increased resistance to water and gas i.e. a decreased permeability in the presence of gamma or neutron radiations or heating sources. The global criterion is composed of a set of 11 dimensionless criteria so that they are additive. The choice of these criteria is inspired from Russian experience in this field. There is also an important experience in France but in the literature therefor there are not given any details regarding either composition or performance. The Romanian experience is very detailed in different concrete compositions but not in concretes of nuclear interest. This issue is very important to be followed in future because of interest in metal economy. (author)

Optimum third harmonic generation efficiency in the far infrared in Si, GaAs and InP

International Nuclear Information System (INIS)

Brazis, R.; Raguotis, R.; Siegrist, M.R.

1997-12-01

We investigate by means of a Monte Carlo technique the nonlinear drift response of electrons to high power electromagnetic waves in Si, GaAs and InP. The first and third harmonic drift velocity amplitudes and phases are presented as function of the pumping wave frequency in the range of 200 to 500 GHz. The third harmonic generation efficiency is found to reach a maximum at a pumping wave amplitude of 10-25 kV/cm depending on the material and the lattice temperature. Cooling down to liquid nitrogen temperature results in an improvement of the efficiency by a factor of 2 to 10, depending on the material and the pumping wave amplitude. Cooled GaAs and InP are both an order of magnitude more efficient than Si at ambient temperature, for which to date the best measured performance has been reported. (author) 2 figs., 5 refs

Legionella risk assessment in water installations Algoritmo de evaluación del riesgo de transmisión de 'Legionella' en instalaciones de transporte y tratamiento de masa de agua

Directory of Open Access Journals (Sweden)

Paulino Pastor Pérez

2005-12-01

Full Text Available Legionelose is an illness produced as a consequence of the inhalation of bacteria of the specie Legionella, which occasionally may colonize some of the water installations of the buildings.This article describes a Legionella risk assessment algorithm particularized for every type of installation covering all the specific characteristics of every piece of equipment, but keeping a common similar structure that allows easiness of use and homogeneous results. This algorithm has been developed by the Experts Commission of the Ministry of Health.The main use of these kind of tools is to minimize as much as possible the subjectivity of the inspectors in the identification and assessment of risks associated to the installations. These types of algorithms are applicable in risks depending on a relative low number of parameters that are somehow easy to control, as it happens in the water installations in the buildings.It has been chosen to develop a global index rated from 0 to 100 (meaning 0 minimum risk and 100 maximum risk distributed in term in three sub indexes, which define the main risk aspects to be taken into account.Structural Index: design.Maintenance Index: maintenance quality.Operational Index: performance of the equipment.Covering all the different aspects of the life of the installations.La legionelosis es una enfermedad producida por la inhalación de bacterias de la especie Legionella, que ocasionalmente pueden colonizar algunas instalaciones de la edificación que utilizan agua para su funcionamiento.El presente articulo describe un algoritmo de evaluación del riesgo de transmisión de legionelosis particularizado para cada tipo de instalación de riesgo a fin de cubrir las características especificas de cada equipo, pero con una estructura común similar, para asegurar la sencillez de uso y la homogeneidad de resultados. Este algoritmo ha sido desarrollado en el seno de la Comisión de Expertos de Legionella del Ministerio de Sanidad

Hydrogen generator characteristics for storage of renewably-generated energy

International Nuclear Information System (INIS)

Kotowicz, Janusz; Bartela, Łukasz; Węcel, Daniel; Dubiel, Klaudia

2017-01-01

The paper presents a methodology for determining the efficiency of a hydrogen generator taking the power requirements of its auxiliary systems into account. Authors present results of laboratory experiments conducted on a hydrogen generator containing a PEM water electrolyzer for a wide range of device loads. On the basis of measurements, the efficiency characteristics of electrolyzers were determined, including that of an entire hydrogen generator using a monitored power supply for its auxiliary devices. Based on the results of the experimental tests, the authors have proposed generalized characteristics of hydrogen generator efficiency. These characteristics were used for analyses of a Power-to-Gas system cooperating with a 40 MW wind farm with a known yearly power distribution. It was assumed that nightly-produced hydrogen is injected into the natural gas transmission system. An algorithm for determining the thermodynamic and economic characteristics of a Power-to-Gas installation is proposed. These characteristics were determined as a function of the degree of storage of the energy produced in a Renewable Energy Sources (RES) installation, defined as the ratio of the amount of electricity directed to storage to the annual amount of electricity generated in the RES installation. Depending on the degree of storage, several quantities were determined. - Highlights: • The efficiency characteristics of PEM electrolyzer are determined. • Generalized characteristics of hydrogen generator efficiency are proposed. • Method of choice of electrolyser nominal power for Power-to-Gas system was proposed. • Development of Power-to-Gas systems requires implementation of support mechanisms.

Algoritmo de manejo del trauma craneoencefálico leve: Una necesidad social en Cuba Algorism for mild craneo - encephalic trauma management social necessity in Cuba

Directory of Open Access Journals (Sweden)

Ariel Varela Hernández

2006-08-01

Full Text Available El tema del traumatismo craneoencefálico leve ha sido poco estudiado es Cuba por lo que se presenta este artículo con el objetivo de demostrar la necesidad social de la aplicación de un algoritmo de manejo de estos pacientes que se adapte al contexto social cubano. Se ofrecen conceptos actualizados sobre la importancia de la ciencia y la tecnología en la sociedad moderna y se aborda la significación de la innovación tecnológica para el desarrollo de la tecnociencia en Cuba. Se trata, basado en una epistemología compleja, las relaciones que se establecen entre el desarrollo social y los servicios de salud, así como entre la evolución de la tecnociencia y el trauma craneoencefálico. Se argumenta la relevancia social del traumatismo craneoencefálico leve tanto a nivel mundial como local, así como el impacto favorable de la aplicación de un algoritmo de manejo de estos enfermos, realizado sobre una base científica, el cual permite un empleo óptimo y racional de las tecnologías imagenológicas de avanzada con que se cuenta.The topic about mild cranium-encephalic traumatism has been little studied in Cuba, that is why this article is presented with the objective to demonstrate the social necessity to apply an algorism for these patient's handling adapted to the Cuban social context. The article offers present-day concepts about the importance of science and technology in modern society and the significance of the technological innovation in the development of the techno-science in Cuba. The relationships between the social development and health services, as well as between the evolution of the techno-science and the cranium-encephalic trauma is treated, based on a complex apistemiology. The article argues the social relevance of the mild cranium-encephalic traumatism in the world and in the country, and the favourable impact of the application of an algorism of these sick persons' handling, carried out upon a scientific base which

Efficient p-n junction-based thermoelectric generator that can operate at extreme temperature conditions

Science.gov (United States)

Chavez, Ruben; Angst, Sebastian; Hall, Joseph; Maculewicz, Franziska; Stoetzel, Julia; Wiggers, Hartmut; Thanh Hung, Le; Van Nong, Ngo; Pryds, Nini; Span, Gerhard; Wolf, Dietrich E.; Schmechel, Roland; Schierning, Gabi

2018-01-01

In many industrial processes, a large proportion of energy is lost in the form of heat. Thermoelectric generators can convert this waste heat into electricity by means of the Seebeck effect. However, the use of thermoelectric generators in practical applications on an industrial scale is limited in part because electrical, thermal, and mechanical bonding contacts between the semiconductor materials and the metal electrodes in current designs are not capable of withstanding thermal-mechanical stress and alloying of the metal-semiconductor interface when exposed to the high temperatures occurring in many real-world applications. Here we demonstrate a concept for thermoelectric generators that can address this issue by replacing the metallization and electrode bonding on the hot side of the device by a p-n junction between the two semiconductor materials, making the device robust against temperature induced failure. In our proof-of-principle demonstration, a p-n junction device made from nanocrystalline silicon is at least comparable in its efficiency and power output to conventional devices of the same material and fabrication process, but with the advantage of sustaining high hot side temperatures and oxidative atmosphere.

Domain-Reversed Lithium Niobate Single-Crystal Fibers are Potentially for Efficient Terahertz Wave Generation

Directory of Open Access Journals (Sweden)

Yalin Lu

2008-01-01

Full Text Available Nonlinear frequency conversion remains one of the dominant approaches to efficiently generate THz waves. Significant material absorption in the THz range is the main factor impeding the progress towards this direction. In this research, a new multicladding nonlinear fiber design was proposed to solve this problem, and as the major experimental effort, periodic domain structure was introduced into lithium niobate single-crystal fibers by electrical poling. The introduced periodic domain structures were nondestructively revealed using a crossly polarized optical microscope and a confocal scanning optical microscope for quality assurance.

Efficient generation of 3.9 W of diffraction-limited green light with spectrally combined tapered diode lasers

DEFF Research Database (Denmark)

Müller, André; Jensen, Ole Bjarlin; Andersen, Peter E.

We propose an efficient concept increasing the power of diode laser systems in the visible spectral range. In comparison with second harmonic generation of single emitters, spectral beam combining with subsequent sum-frequency generation enhances the available power significantly. Combining two...... 1060 nm tapered diode lasers, we achieve a 2.5-3.2 fold increase of green light with a maximum power of 3.9 Watts in a diffraction-limited beam. At this level, diode lasers have a high application potential, for example, within the biomedical field. In order to enhance the power even further, our...

Algoritmo para el control metabólico del paciente diabético en el periodo posoperatorio de la cirugía cardiovascular

Directory of Open Access Journals (Sweden)

Maikel Rodulfo García

2014-07-01

Full Text Available El paciente con diabetes mellitus en el periodo posoperatorio de la cirugía cardiovascular, frecuentemente presenta descontrol en sus niveles de glucemia, debido a las consecuencias metabólicas que traen consigo, tanto el aumento de hormonas contra-reguladoras como la resistencia y/o disminución de los niveles de insulina, causado por el estrés quirúrgico al cual se expone el organismo. Su control es esencial durante la cirugía y luego de esta, pues de ello depende la evolución de los afectados; por tanto, es de vital importancia poseer una guía que permita orientarse para mantener las cifras de glucemia en valores adecuados. Se presenta un algoritmo terapéutico de fácil aplicación, elaborado en el Servicio de Cirugía Cardiovascular del Hospital Provincial Docente Clinicoquirúrgico "Saturnino Lora Torres" de Santiago de Cuba, con vistas a tratar la hiperglucemia, que pueda generalizarse al resto de los centros del país

Bubble-generating nano-lipid carriers for ultrasound/CT imaging-guided efficient tumor therapy.

Science.gov (United States)

Zhang, Nan; Li, Jia; Hou, Ruirui; Zhang, Jiangnan; Wang, Pei; Liu, Xinyang; Zhang, Zhenzhong

2017-12-20

Ideal therapeutic effectiveness of chemotherapy is obtained only when tumor cells are exposed to a maximal drug concentration, which is often hindered by dose-limiting toxicity. We designed a bubble-generating liposomal delivery system by introducing ammonium bicarbonate and gold nanorods into folic acid-conjugated liposomes to allow both multimodal imaging and the local release of drug (doxorubicin) with hyperthermia. The key component, ammonium bicarbonate, allows a controlled, rapid release of doxorubicin to provide an effective drug concentration in the tumor microenvironment. An in vitro temperature-triggered drug release study showed that cumulative release improved more than two-fold. In addition, in vitro and in vivo studies indicated that local heat treatment or ultrasonic cavitation enhanced the therapeutic efficiency greatly. The delivery system could also serve as an excellent contrast agent to allow ultrasonic imaging and computerized tomography imaging simultaneously to further achieve the aim of accurate diagnostics. Results of this study showed that this versatile bubble-generating liposome is a promising system to provide optimal therapeutic effects that are guided by multimodal imaging. Copyright © 2017 Elsevier B.V. All rights reserved.

Efficiency factors of singlet oxygen generation from core-modified expanded porphyrin: tetrathiarubyrin in ethanol

CERN Document Server

Ha, J H; Kim, Y R; Jung, G Y; Lee, Y H; Shin, K

2001-01-01

The photophysical properties and the singlet oxygen generation efficiency of tetrathiarubyrin have been investigated to elucidate the possibility of its use as a photodynamic therapy (PDT) photosensitizer by steady-state and time-resolved spectroscopic methods. The observed photophysical properties were affected by various molecular aspects, such as extended pi conjugation, structural distortion, and internal heavy atom. The steady-state electronic absorption spectrum was red-shifted due to the extended pi-conjugation, and the spin orbital coupling was enhanced by the structural distortion and the internal heavy atom effect. As a result of the enhanced spin orbital coupling, the triplet quantum yield increased to 0.90 +- 0.10 and the triplet state lifetime was shortened to 7.0 +- 1.2 mu s. Since the triplet state decays at a relatively faster rate, the efficiency of the oxygen quenching of the triplet state decreases. The singlet oxygen quantum yield was estimated to be 0.52 +- 0.02, which is somewhat lower t...

PVP-stabilized Ru–Rh nanoparticles as highly efficient catalysts for hydrogen generation from hydrolysis of ammonia borane

International Nuclear Information System (INIS)

Rakap, Murat

2015-01-01

Herein, the utilization of poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles (3.4 ± 1.4 nm) as highly efficient catalysts in the hydrolysis of ammonia borane for hydrogen generation is reported. They are prepared by co-reduction of ruthenium and rhodium metal ions in ethanol/water mixture by an alcohol reduction method and characterized by transmission electron microscopy-energy dispersive X-ray spectroscopy, ultraviolet–visible spectroscopy, and X-ray photoelectron spectroscopy. They are durable and highly efficient catalysts for hydrogen generation from the hydrolysis of ammonia borane even at very low concentrations and temperature, providing average turnover frequency of 386 mol H 2 (mol cat) −1 min −1 and maximum hydrogen generation rate of 10,680 L H 2 min −1 (mol cat) −1 . Poly(N-vinyl-2-pyrrolidone)-protected ruthenium–rhodium nanoparticles also provide activation energy of 47.4 ± 2.1 kJ/mol for the hydrolysis of ammonia borane. - Highlights: • Ru-Rh@PVP NPs provide a TOF of 386 mol H 2 (mol cat) −1 min −1 for hydrolysis of AB. • Maximum HG rate is 9680 L H 2 min −1 (mol cat) −1 for the hydrolysis of AB. • Activation energy is 47.4 ± 2.1 kJ mol −1 for the hydrolysis of AB

High efficiency particulate air filter technology from 1980 to 1985 in the Central Electricity Generating Board

International Nuclear Information System (INIS)

Skledon, R.; Taylor, S.; Fern, C.; Stead, M.

1986-01-01

This paper examines at the Central Electricity Generating Board's methods of High Efficiency Particulate Air (1,700 m 3 /hr) filter testing from conception to the present day. The choice of the test and the early results are looked at followed by the development using new test equipment for checking ladderframe systems. The need for the drawing up of the Central Electricity Generating Board 743401 Standard for filter manufacture and its effect on full implementation is looked into. The advantages and disadvantages of our test procedures are reflected upon and the future developments in test methods and filters for use by the C.E.G.B. in their power stations are discussed. (author)

Efficient and rapid derivation of primitive neural stem cells and generation of brain subtype neurons from human pluripotent stem cells.

Science.gov (United States)

Yan, Yiping; Shin, Soojung; Jha, Balendu Shekhar; Liu, Qiuyue; Sheng, Jianting; Li, Fuhai; Zhan, Ming; Davis, Janine; Bharti, Kapil; Zeng, Xianmin; Rao, Mahendra; Malik, Nasir; Vemuri, Mohan C

2013-11-01

Human pluripotent stem cells (hPSCs), including human embryonic stem cells and human induced pluripotent stem cells, are unique cell sources for disease modeling, drug discovery screens, and cell therapy applications. The first step in producing neural lineages from hPSCs is the generation of neural stem cells (NSCs). Current methods of NSC derivation involve the time-consuming, labor-intensive steps of an embryoid body generation or coculture with stromal cell lines that result in low-efficiency derivation of NSCs. In this study, we report a highly efficient serum-free pluripotent stem cell neural induction medium that can induce hPSCs into primitive NSCs (pNSCs) in 7 days, obviating the need for time-consuming, laborious embryoid body generation or rosette picking. The pNSCs expressed the neural stem cell markers Pax6, Sox1, Sox2, and Nestin; were negative for Oct4; could be expanded for multiple passages; and could be differentiated into neurons, astrocytes, and oligodendrocytes, in addition to the brain region-specific neuronal subtypes GABAergic, dopaminergic, and motor neurons. Global gene expression of the transcripts of pNSCs was comparable to that of rosette-derived and human fetal-derived NSCs. This work demonstrates an efficient method to generate expandable pNSCs, which can be further differentiated into central nervous system neurons and glia with temporal, spatial, and positional cues of brain regional heterogeneity. This method of pNSC derivation sets the stage for the scalable production of clinically relevant neural cells for cell therapy applications in good manufacturing practice conditions.

Desarrollo de un algoritmo para la generación y elección de soluciones de corte en la operación de canteo y despuntado en aserraderos

Directory of Open Access Journals (Sweden)

Francisco Vergara González

2011-01-01

Full Text Available En este trabajo se desarrolló un algoritmo que integra las mejores prácticas aplicadas en los aserraderos y una metodología de análisis geométrico de líneas de corte. La aplicación fue programada en lenguaje C++, siendo alimentada con las dimensiones de las piezas deseadas de producir, sus respectivos precios y la geometría en 2-D de la tapa a cortar, generando como resultado una solución de corte en ancho y largo para tapa ingresada. Las soluciones obtenidas se compararon con un patrón que corresponde a soluciones entregadas por un equipo de corte ¿optimizado¿, de un aserradero del sur de Chile. Cuatro tipos de soluciones se obtuvieron al ingresar la geometría de las tapas, la cual fue capturada con 4 pasos de lectura diferentes. Los resultados muestran que las soluciones obtenidas con paso de lectura 100 mm son en promedio un 4% superior al patrón, y muy superiores a las otras soluciones obtenidas con los otros 3 pasos. Haciendo abstracción de las condiciones particulares de operación de cada método. Una comparación teórica de tiempos por método de solución, indica que los 77 milisegundos empleados por SISCORMAD, son significativamente inferiores a los 320 milisegundos obtenidos con programación dinámica, 890 milisegundos con enumeración exhaustiva, y 140 milisegundos obtenidos con método heurístico geométrico como tiempos de solución reportados por programación dinámica [6]. Esta característica hace muy atractivo al algoritmo desarrollo para ser empleado en futuras aplicaciones. Sin embargo, dada la naturaleza heurística de SISCORMAD, constituye solo una solución de alta calidad, pero no óptima.

A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

Science.gov (United States)

Aziz, Nur Liyana Afiqah Abdul; Siah Yap, Keem; Afif Bunyamin, Muhammad

2013-06-01

This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of "computing the word". The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

A hybrid fuzzy logic and extreme learning machine for improving efficiency of circulating water systems in power generation plant

International Nuclear Information System (INIS)

Aziz, Nur Liyana Afiqah Abdul; Yap, Keem Siah; Bunyamin, Muhammad Afif

2013-01-01

This paper presents a new approach of the fault detection for improving efficiency of circulating water system (CWS) in a power generation plant using a hybrid Fuzzy Logic System (FLS) and Extreme Learning Machine (ELM) neural network. The FLS is a mathematical tool for calculating the uncertainties where precision and significance are applied in the real world. It is based on natural language which has the ability of c omputing the word . The ELM is an extremely fast learning algorithm for neural network that can completed the training cycle in a very short time. By combining the FLS and ELM, new hybrid model, i.e., FLS-ELM is developed. The applicability of this proposed hybrid model is validated in fault detection in CWS which may help to improve overall efficiency of power generation plant, hence, consuming less natural recourses and producing less pollutions.

Cinemática inversa de robot serial utilizando algoritmo genético basado en MCDS

Directory of Open Access Journals (Sweden)

Juan Jairo Vaca González

2015-04-01

Full Text Available Los robots manipuladores seriales son herramientas eficaces para realizar tareas repetitivas y de precisión en la industria, siempre que se comprenda la cinemática involucrada en el posicionamiento y orientación del efector final. Este artículo presenta una metodología para resolver el problema cinemático inverso de un robot serial (Melfa RV-2A utilizando un algoritmo genético (AG a partir del modelo cinemático directo Screws (MCDS. Para esto, se obtienen los parámetros Screw que modelan el robot, se calcula el espacio de trabajo asociado y se diseña el AG contemplando una función multi-objetivo de alcance de posición y orientación en que se sitúa el efector final, con respecto a una coordenada y orientación de un punto objetivo establecido. La validación del AG se realiza según la aptitud, el tiempo de convergencia y la cantidad de generaciones usadas por la función para alcanzar el objetivo. Por tanto, la implementación de un AG basado en un MCDS es una herramienta prometedora que podría utilizarse para calcular la cinemática inversa de robots seriales. Esta novedosa implementación permite establecer por primera vez la exposición matricial de un sistema cinemático directo para obtener la solución cinemática inversa de un robot serial. En consecuencia, se demuestra que esta es una metodología factible y eficiente para solucionar la cinemática inversa de cualquier tipo de robot manipulador.

Hybrid pressure retarded osmosis-membrane distillation system for power generation from low-grade heat: thermodynamic analysis and energy efficiency.

Science.gov (United States)

Lin, Shihong; Yip, Ngai Yin; Cath, Tzahi Y; Osuji, Chinedum O; Elimelech, Menachem

2014-05-06

We present a novel hybrid membrane system that operates as a heat engine capable of utilizing low-grade thermal energy, which is not readily recoverable with existing technologies. The closed-loop system combines membrane distillation (MD), which generates concentrated and pure water streams by thermal separation, and pressure retarded osmosis (PRO), which converts the energy of mixing to electricity by a hydro-turbine. The PRO-MD system was modeled by coupling the mass and energy flows between the thermal separation (MD) and power generation (PRO) stages for heat source temperatures ranging from 40 to 80 °C and working concentrations of 1.0, 2.0, and 4.0 mol/kg NaCl. The factors controlling the energy efficiency of the heat engine were evaluated for both limited and unlimited mass and heat transfer kinetics in the thermal separation stage. In both cases, the relative flow rate between the MD permeate (distillate) and feed streams is identified as an important operation parameter. There is an optimal relative flow rate that maximizes the overall energy efficiency of the PRO-MD system for given working temperatures and concentration. In the case of unlimited mass and heat transfer kinetics, the energy efficiency of the system can be analytically determined based on thermodynamics. Our assessment indicates that the hybrid PRO-MD system can theoretically achieve an energy efficiency of 9.8% (81.6% of the Carnot efficiency) with hot and cold working temperatures of 60 and 20 °C, respectively, and a working solution of 1.0 M NaCl. When mass and heat transfer kinetics are limited, conditions that more closely represent actual operations, the practical energy efficiency will be lower than the theoretically achievable efficiency. In such practical operations, utilizing a higher working concentration will yield greater energy efficiency. Overall, our study demonstrates the theoretical viability of the PRO-MD system and identifies the key factors for performance

Elaboración de un modelo evolutivo híbrido de algoritmos genéticos y redes neuronales artificiales para dosificaciones de mezclas de concreto reforzadas con fibras metálicas

Directory of Open Access Journals (Sweden)

Luis Octavio González Salcedo

2016-06-01

Full Text Available En un ambiente computacional, un modelo evolutivo es desarrollado para proponer dosificaciones de mezclas de concretos reforzados con fibras metálicas, para solicitudes de resistencia a la compresión. El modelo es híbrido al incluir un sistema de dosificación basado en algoritmos genéticos y un sistema de estimación de propiedades basado en redes neuronales artificiales. Los resultados obtenidos son comparados con un sistema de dosificaciones reportado experimentalmente. Estas comparaciones muestran una aproximación en el proceso de simulación. Además, por las características del modelo, se considera de aporte en la tecnología del concreto.

Modelo hipercubo integrado a um algoritmo genético para análise de sistemas médicos emergenciais em rodovias The hypercube queuing model integrated to a genetic algorithm to analyze emergency medical systems on highways

Directory of Open Access Journals (Sweden)

Ana Paula Iannoni

2006-04-01

Full Text Available O modelo hipercubo, conhecido na literatura de problemas de localização de sistemas servidor para cliente, é um modelo baseado em teoria de filas espacialmente distribuídas e aproximações Markovianas. O modelo pode ser modificado para analisar os sistemas de atendimentos emergenciais (SAEs em rodovias, considerando as particularidades da política de despacho destes sistemas. Neste estudo, combinou-se o modelo hipercubo com um algoritmo genético para otimizar a configuração e operação de SAEs em rodovias. A abordagem é efetiva para apoiar decisões relacionadas ao planejamento e operação destes sistemas, por exemplo, em determinar o tamanho ideal para as áreas de cobertura de cada ambulância, de forma a minimizar o tempo médio de resposta aos usuários e o desbalanceamento das cargas de trabalho das ambulâncias. Os resultados computacionais desta abordagem foram analisados utilizando dados reais do sistema Anjos do Asfalto (rodovia Presidente Dutra.The hypercube model, well-known in the literature on problems of server-to-customer localization systems, is based on the spatially distributed queuing theory and Markovian analysis approximations. The model can be modified to analyze Emergency Medical Systems (EMSs on highways, considering the particularities of these systems' dispatching policies. In this study, we combine the hypercube model with a genetic algorithm to optimize the configuration and operation of EMSs on highways. This approach is effective to support planning and operation decisions, such as determining the ideal size of the area each ambulance should cover to minimize not only the average time of response to the user but also ambulance workload imbalances, as well as generating a Pareto efficient boundary between these measures. The computational results of this approach were analyzed using real data Anjos do Asfalto EMS (which covers the Presidente Dutra highway.

Chiral crystal of a C2v-symmetric 1,3-diazaaulene derivative showing efficient optical second harmonic generation

KAUST Repository

Ma, Xiaohua; Fu, Limin; Zhao, Yunfeng; Ai, Xicheng; Zhang, Jianping; Han, Yu; Guo, Zhixin

2011-01-01

the moderate static first hyperpolarizabilities (β0) for both APNA [(136 ± 5) à - 10-30 esu] and DPAPNA [(263 ± 20) à - 10-30 esu], only APNA crystal shows a powder efficiency of second harmonic generation (SHG) of 23 times that of urea. It is shown

Fluidic oscillator-mediated microbubble generation to provide cost effective mass transfer and mixing efficiency to the wastewater treatment plants.

Science.gov (United States)

Rehman, Fahad; Medley, Gareth J D; Bandulasena, Hemaka; Zimmerman, William B J

2015-02-01

Aeration is one of the most energy intensive processes in the waste water treatment plants and any improvement in it is likely to enhance the overall efficiency of the overall process. In the current study, a fluidic oscillator has been used to produce microbubbles in the order of 100 μm in diameter by oscillating the inlet gas stream to a pair of membrane diffusers. Volumetric mass transfer coefficient was measured for steady state flow and oscillatory flow in the range of 40-100l/min. The highest improvement of 55% was observed at the flow rates of 60, 90 and 100l/min respectively. Standard oxygen transfer rate and efficiency were also calculated. Both standard oxygen transfer rate and efficiency were found to be considerably higher under oscillatory air flow conditions compared to steady state airflow. The bubble size distributions and bubble densities were measured using an acoustic bubble spectrometer and confirmed production of monodisperse bubbles with approximately 100 μm diameters with fluidic oscillation. The higher number density of microbubbles under oscillatory flow indicated the effect of the fluidic oscillation in microbubble production. Visual observations and dissolved oxygen measurements suggested that the bubble cloud generated by the fluidic oscillator was sufficient enough to provide good mixing and to maintain uniform aerobic conditions. Overall, improved mass transfer coefficients, mixing efficiency and energy efficiency of the novel microbubble generation method could offer significant savings to the water treatment plants as well as reduction in the carbon footprint. Copyright © 2014 Elsevier Inc. All rights reserved.

[Efficiency of oxidant gas generator cells powered by electric or solar energy].

Science.gov (United States)

Brust Carmona, H; Benitez, A; Zarco, J; Sánchez, E; Mascher, I

1998-02-01

Diseases caused by microbial contaminants in drinking water continue to be a serious problem in countries like Mexico. Chlorination, using chlorine gas or chlorine compounds, is one of the best ways to treat drinking water. However, difficulties in handling chlorine gas and the inefficiency of hypochlorite solution dosing systems--due to sociopolitical, economic, and cultural factors--have reduced the utility of these chlorination procedures, especially in far-flung and inaccessible rural communities. These problems led to the development of appropriate technologies for the disinfection of water by means of the on-site generation of mixed oxidant gases (chlorine and ozone). This system, called MOGGOD, operates through the electrolysis of a common salt solution. Simulated system evaluation using a hydraulic model allowed partial and total costs to be calculated. When powered by electrical energy from the community power grid, the system had an efficiency of 90%, and in 10 hours it was able to generate enough gases to disinfect about 200 m3 of water at a cost of approximately N$8 (US $1.30). When the electrolytic cell was run on energy supplied through a photoelectric cell, the investment costs were higher. A system fed by photovoltaic cells could be justified in isolated communities that lack electricity but have a gravity-fed water distribution system.