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Sample records for cu-ni-sn para fins

  1. "Estudos do desenvolvimento e caracterização das ligas Cu-Ni-Pt e Cu-Ni-Sn para fins eletro-eletrônicos"

    OpenAIRE

    Luis Carlos Elias da Silva

    2006-01-01

    O Cu e suas ligas têm diferentes aplicações na sociedade moderna devido as excelentes propriedades elétricas, condutividade térmica, resistência à corrosão dentre outras propriedades. Estas aplicações podem ser em válvulas, tubulações, panelas para absorção de energia solar, radiadores para automóveis, condutores de corrente e eletrônico, elementos de termostatos e partes estruturais de reatores nucleares, como, por exemplo, bobinas para campo toroidal para um reator de fusão nuclear. Dentre ...

  2. Studies of the development and characterization of the Cu-Ni-Pt and Cu-Ni-Sn alloys for electro-electronic uses; Estudos do desenvolvimento e caracterizacao das ligas Cu-Ni-Pt e Cu-Ni-Sn para fins eletro-eletronicos

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Luis Carlos Elias da

    2006-07-01

    The Cu and its alloys have different applications in the owed modern society the excellent electric properties, thermal conductivity, resistance to the corrosion and other properties. These applications can be in valves, pipes, pots for absorption of solar energy, radiators for automobiles, current driver, electronic driver, thermostats elements and structural parts of nuclear reactors, as, for example, reels for field toroidal for a reactor of nuclear coalition. The alloys used in nuclear reactors, we can highlight Cu-Be, Cu-Sn and Cu-Pt. Ni and Co frequently are added to the Cu alloys so that the solubility is moved for temperatures more elevated with relationship to the binary systems of Cu-Sn and Cu-Pt. The addition of Ni-Pt or Ni-Sn to the Cu in the same or inferior percentages to 1,5% plus thermomechanical treatments changes the properties of the copper. We studied the electric conductivity and hardness Vickers of the Cu-Ni-Pt and Cu-Ni-Sn and compared with the electrolytic Cu. In the proposed flowcharts, breaking of the obtaining of the ingot, we proceeded with thermo mechanical treatments. (author)

  3. Reactions in Electrodeposited Cu/Sn and Cu/Ni/Sn Nanoscale Multilayers for Interconnects

    Directory of Open Access Journals (Sweden)

    Pay Ying Chia

    2016-05-01

    Full Text Available Miniaturization of electronic devices has led to the development of 3D IC packages which require ultra-small-scale interconnections. Such small interconnects can be completely converted into Cu-Sn based intermetallic compounds (IMCs after reflow. In an effort to improve IMC based interconnects, an attempt is made to add Ni to Cu-Sn-based IMCs. Multilayer interconnects consisting of stacks of Cu/Sn/Cu/Sn/Cu or Cu/Ni/Sn/Ni/Sn/Cu/Ni/Sn/Ni/Cu with Ni = 35 nm, 70 nm, and 150 nm were electrodeposited sequentially using copper pyrophosphate, tin methanesulfonic, and nickel Watts baths, respectively. These multilayer interconnects were investigated under room temperature aging conditions and for solid-liquid reactions, where the samples were subjected to 250 °C reflow for 60 s and also 300 °C for 3600 s. The progress of the reaction in the multilayers was monitored by using X-ray Diffraction, Scanning Electron Microscope, and Energy dispersive X-ray Spectroscopy. FIB-milled samples were also prepared for investigation under room temperature aging conditions. Results show that by inserting a 70 nanometres thick Ni layer between copper and tin, premature reaction between Cu and Sn at room temperature can be avoided. During short reflow, the addition of Ni suppresses formation of Cu3Sn IMC. With increasing Ni thickness, Cu consumption is decreased and Ni starts acting as a barrier layer. On the other hand, during long reflow, two types of IMC were found in the Cu/Ni/Sn samples which are the (Cu,Ni6Sn5 and (Cu,Ni3Sn, respectively. Details of the reaction sequence and mechanisms are discussed.

  4. Surface planarization of Cu and CuNiSn Micro-bumps embedded in polymer for below 20μm pitch 3DIC applications

    OpenAIRE

    De Preter, Inge; Derakhshandeh, Jaber; Heylen, Nancy; Van Acker, Lut; June Rebibis, Kenneth; Miller, Andy; Beyer, Gerald; Beyne, Eric

    2016-01-01

    Planarization techniques such as Surface planer (better known as Fly-cut) and chemical-mechanical polishing (CMP) can be used to improve the bump roughness and bump height uniformity within the die and wafer which can be beneficial for solder based bump stacking and Cu-Cu direct bonding [1]. In this paper the influence of both planarization techniques on 20μm pitch Cu and CuNiSn bumps embedded in polymer are studied. The polymer protects the bumps from the shearing force of the planarization ...

  5. 界面耦合作用对Cu(Ni)/Sn-Ag-Cu/Cu(Ni)BGA 焊点界面IMC形成与演化的影响%EFFECT OF THE CROSS-INTERACTION ON THE FORMATION AND EVOLUTION OF INTERMETALLIC COMPOUNDS IN Cu(Ni)/Sn-Ag-Cu/Cu(Ni) BGA STRUCTURE SOLDER JOINTS

    Institute of Scientific and Technical Information of China (English)

    李勋平; 周敏波; 夏建民; 马骁; 张新平

    2011-01-01

    研究了焊盘材料界面耦合作用对Cu(Ni)/Sn-3.0Ag-0.5Cu/Cu(Ni)BGA(Ball Grid Array)结构焊点焊后态和125℃等温时效过程中界面金属间化合物(IMC)的成分、形貌和生长动力学的影响.结果表明,凸点下金属层(UBM)Ni界面IMC的成分与钎料中Cu含量有关,钎料中Cu含量较高时界面IMC为(Cu,Ni)6Sn5,而Cu含量较低时,则生成(Cu,Ni)3Sn4;Cu-Ni耦合易导致Cu/Sn-3.0Ag-0.5Cu/Ni焊点中钎料/Ni界面IMC异常生长并产生剥离而进入钎料.125℃等温时效过程中,Sn-3.0Ag-0.5Cu/Cu界面IMC的生长速率常数随钎料中Cu含量增加而提高,Cu-Cu耦合降低一次回流侧IMC生长速率常数;Cu-Ni耦合和Ni-Ni耦合均导致焊点一次回流Ni侧界面IMC的生长速率常数增大,但Ni对界面IMC生长动力学的影响大于Cu;Ni有利于抑制Cu界面Cu3Sn生长,降低界面IMC生长速率,但Cu-Ni耦合对Cu界面Cu3Sn中Kirkendall空洞率无明显影响.%The formation and evolution of interfacial intermetallic compounds (IMCs) in Cu(Ni)/Sn-3.0Ag-0.5Cu/Cu(Ni) BGA (Ball Grid Array) structure solder joints both in the asreflowed state and undergoing isothermal aging at 125 C were investigated. The results show that there exists a significant cross-interaction effect of the solder pad/under bump metal (UBM) on the composition, morphology and growth kinetics of interfacial IMCs in solder joints. The reactions of solder/Ni UBM strongly depends on the Cu content of the solder, for a high Cu content, a continuous (Cu, Ni)6Sn5 layer forms at the interface, while for a low Cu content, a continuous (Ni, Cu)3Sn4 layer appears at the interface. The cross-interaction of Cu and Ni in Cu/Sn-3.0Ag-0.5Cu(SAC)/Ni solder joints has obvious influence on the composition and morphology of the interfacial IMC; and the IMC spalling phenomenon occurs at the interface of Ni side. During isothermal aging at 125 ℃, the growth rate constant of the interfacial IMC layer in SAC/Cu and Cu/SAC/Cu joints increases with

  6. Estrabismo após toxina botulínica para fins estéticos

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    Marta Halfeld Ferrari Alves Lacordia

    2011-06-01

    Full Text Available RESUMO Nas últimas décadas, a toxina botulínica tem sido aplicada para fins terapêuticos em inúmeras afecções. A toxina do tipo A foi aprovada primeiramente em 1989 para o uso em estrabismo, blefaroespasmo e espasmo hemifacial de pacientes maiores que 12 anos de idade. A observação de que pacientes tratados de blefaroespasmo com toxina botulínica apresentavam um efeito adicional de diminuição das rugas de expressão inspirou estudos sobre a aplicação cosmética da toxina. Recentemente, a toxina botulínica do tipo A foi aprovada para fins estéticos. Este trabalho relata um caso de ocorrência de estrabismo após aplicação de toxina botulínica na face para fins estéticos.

  7. Los laberintos del miedo. Un recorrido para fin de siglo

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    Rossana Reguillo

    2000-01-01

    Full Text Available Desde la comunidad tribal hasta la megalópolis, a lo largo de la historia, los grupos sociales han buscado diferentes mecanismos para enfrentar la fragilidad y vencer el miedo. Desde los amuletos protectores, hasta la constitución del Estado, la Historia de la humanidad es la historia de la larga búsqueda para contrerrestar los efectos de las fuerzas que amenazan la permanencia, la estabilidad, la certeza de la vida.

  8. Tácticas para realizar juegos sin fin.

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    Teresa Suárez Rodríguez

    1981-01-01

    Full Text Available El tema del tratamiento de familias que poseen miembros psicóticos o esquizofrénicos es, en nuestros días, un tema clásico en la literatura psiquiátrica (1, 2, 3, 4. A pesar de esto, hemos elegido para nuestro artículo el presentar un tratamiento con una de estas familias con una doble finalidad: a Exponer un caso que se aproxime al máximo a las características de los pacientes que se encuentran habitualmente en la psiquiatría pública y comunitaria. b Mostrar cómo este tipo de tratamiento puede servir como alternativa a la hospitalización en las crisis, y esto aún trabajando en unas condiciones que están lejos de ser el modelo más adecuado para una intervención en la crisis (equipo multipersonal, horarios elásticos, etc. (5. Pensamos que para que un trabajo así pueda realizarse, los objetivos terapéuticos tienen que ser, desde el comienzo, claros y precisos, dado que este tipo de familias con miembros esquizofrénicos son especialmente expertas en confundir

  9. POTENCIAL FARMACOINDUSTRIAL DE Trichoderma harzianum PARA FINS FARMACOTERAPÊUTICOS

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    Luís Fernando Albarello Gellen

    2014-12-01

    Full Text Available Linhagens de Trichoderma estão bem difundidas nos processos de controle de fitopatógenos, além disto, para promoção do desenvolvimento e crescimento das culturas onde são inoculados, estes benefícios dão-se pela gama de processos desempenhados por este organismo, os processos são classificados em parasitismo, antibiose e competição, além de secretarem produtos enzimáticos com ações degradantes, compostos voláteis e antimicrobianos. Por meio de testes de produção enzimática, confronto em placa, metabólitos voláteis e sensibilização do agente, os isolados de Trichoderma harzianum mostraram-se como um potente produtor de substâncias antimicrobianas e antifúngicas perante Sthaphylococcus aureus, Streptococcus pyogenes, E. coli, Pseudomonas aeruginosa, E. faecalis e Rhodotorula sp., Candida albicans, Candida parapsilosis e Candida lusitaniae. Palavras-chave: antimicrobianos, antifúngicas, metabólitos, sensibilização. DOI: http://dx.doi.org/10.18561/2179-5746/biotaamazonia.v4n4p91-96

  10. Estrabismo após toxina botulínica para fins estéticos

    OpenAIRE

    Marta Halfeld Ferrari Alves Lacordia; Flávia Sotto-Maior Januário; Júlio César Costa Pereira

    2011-01-01

    RESUMO Nas últimas décadas, a toxina botulínica tem sido aplicada para fins terapêuticos em inúmeras afecções. A toxina do tipo A foi aprovada primeiramente em 1989 para o uso em estrabismo, blefaroespasmo e espasmo hemifacial de pacientes maiores que 12 anos de idade. A observação de que pacientes tratados de blefaroespasmo com toxina botulínica apresentavam um efeito adicional de diminuição das rugas de expressão inspirou estudos sobre a aplicação cosmética da toxina. Recentemente, a toxina...

  11. Del Paseo de las Delicias a Corrientes : El largo fin de la guerra para un soldado

    OpenAIRE

    Natalia Corbellini

    2006-01-01

    El texto refiere una entrevista mantenida con un soldado republicano que se alista en Madrid, a quien fin de la guerra lo encuentra pasando a Francia por Cataluña. El diálogo refleja el largo camino que debió transitar aquel joven soldado, luego de soportar los campos de concentración franceses, para poder arribar a Monte Caseros, un pequeño pueblo del litoral argentino donde parte de su familia lo esperaba para que pudiera establecerse y llevar adelante una vida. The text refers an interv...

  12. Estrabismo após toxina botulínica para fins estéticos

    OpenAIRE

    Marta Halfeld Ferrari Alves Lacordia; Flávia Sotto-Maior Januário; Júlio César Costa Pereira

    2011-01-01

    RESUMO Nas últimas décadas, a toxina botulínica tem sido aplicada para fins terapêuticos em inúmeras afecções. A toxina do tipo A foi aprovada primeiramente em 1989 para o uso em estrabismo, blefaroespasmo e espasmo hemifacial de pacientes maiores que 12 anos de idade. A observação de que pacientes tratados de blefaroespasmo com toxina botulínica apresentavam um efeito adicional de diminuição das rugas de expressão inspirou estudos sobre a aplicação cosmética da toxina. Recentemente, a toxina...

  13. Casas estudio: alternativa pedagógica para el proyecto de fin de carrera

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    Edison Henao Carvajal

    2011-12-01

    Full Text Available Este artículo da cuenta del proceso de elaboración del trabajo de grado de algunos de los estudiantes inscritos en la Línea de Profundización en Proyectos Arquitectónicos, del programa curricular de Arquitectura, de la sede Manizales de la Universidad Nacional de Colombia, durante los semestres segundo del 2009 y primero del 2010. El propósito de la experiencia, coordinada por los autores del artículo, consistió en poner a prueba un método de enseñanza-aprendizaje para el taller de proyectos de fin de carrera, en el marco de una concepción pedagógica basada en la solución de problemas de forma, a partir del reconocimiento y de la asimilación de las soluciones universales presentes en las obras de los grandes maestros de la arquitectura. En contravía de la metodología de concepción arquitectónica contemporánea, basada en “la realización de las ideas del autor”, el taller se centró en recuperar las maneras de operar de la modernidad arquitectónica, en las que tiene mayor importancia la búsqueda de una implantación correcta de la obra, la solución de los requerimientos programáticos del proyecto, su concepción constructiva y el planteamiento consistente de los espacios requeridos, en este caso, para una casa-estudio.

  14. “Alice", en Ella y otras mujeres, de Rubem Fonseca: el antivalor como medio para alcanzar el fin

    OpenAIRE

    Cano Jaramillo, Ana María

    2011-01-01

    Los valores, como el conjunto de facultades que guían al ser humano en sus acciones y que determinan lo bueno y lo malo de su comportamiento, están directamente relacionados con la educación que los miembros de una sociedad han recibido dependiendo de su cultura y sus creencias -- Analizar la transgresión de los valores sociales que se presenta en el cuento “Alice”, de Rubem Fonseca, para demostrar cómo en la historia el fin justifica los medios, aunque estos estén en contravía de la axiologí...

  15. Conteúdos hipermodais para fins de aprendizagem: usos em contexto pelos alunos Hypermodal content to learning: student's contextualized use

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    Eduardo S Junqueira

    2010-12-01

    Full Text Available A análise dos usos de artefatos e conteúdos hipermodais pelos alunos, para fins de aprendizagem na modalidade do ensino a distância, indicou dois elementos-chave. A estrutura e a coesão dos conteúdos, identificados a partir de categorias estáveis de análi se semiótica de materiais hipermodais, não determinaram o uso. Norteados por elemen tos culturais e por suas intenções, os alunos formularam práticas comunicativas que extrapolaram a dicotomia impresso/digital. Imprimiram os conteúdos disponibilizados na tela do computador e instituíram a centralidade do impresso para a aprendizagem, sem, no entanto, ignorar os conteúdos hipermodais. A partir do impresso, utilizaram tais conteúdos em "rede" e construíram trilhas de navegação e leitura coerentes, voltadas a fins de aprendizagem específicos. Indica-se a necessidade de processos flexíveis e com a participação dos usuários-alunos para a produção de conteúdos mais interativos e democráticos.The analysis of the use of hypermodal artifacts and content by distance learning students indicated two key elements. Content structure and cohesion, estab lished by stable semiotic categories of hypermodal artifact's analysis, indicated that they have not determined the student's use. Guided by cultural elements and their own goals, students established communicative practices that extrapolated the print/digital dichoto my. The students printed the online content and established the centrality of the print ing material for their learning without disregarding hypermodal content. From the print ing material, they used content as "webs" and developed paths as they coherently navi gated and read the materials. The study indicates the need to establish flexible, open to participation processes of content design aimed at the student's participation to produce more interactive and democratic content for the production of learning.

  16. DESEMPENHO DE UM INJETOR DE FERTILIZANTES DO TIPO VENTURI PARA FINS DE FERTIRRIGAÇÃO

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    J.O.P FERREIRA

    1996-01-01

    Full Text Available Com o objetivo de avaliar as características hidráulicas de um injetor de fertilizantes do tipo Venturi, construído de polietileno, realizou-se um teste de desempenho em laboratório. O injetor utilizado foi o modelo Mazzei 1078, possuindo 200 mm de comprimento, 19,6 mm de diâmetro interno nas seções de entrada e saída e 7,6 mm de diâmetro interno no corpo cilindrico ("garganta". Os testes foram realizados às pressões de alimentação de 10, 15, 20, 25 e 30 m.c.a., com os respectivos diferenciais de pressão: 2, 3 e 4; 4, 5 e 6; 4, 5 e 6; 6 e 7; 7 e 8 m.c.a.. Os parâmetros de desempenho analisados foram curvas de vazão de sucção versus tensão de sucção e rendimento. Os pares de valores de vazão de sucção e tensão de sucção foram submetidos à análise estatística de regressão, sendo o modelo linear o que melhor se ajustou aos valores observados. Para uma pressão de alimentação constante, a vazão de sucção aumentou com o aumento do diferencial de pressão e, para um diferencial de pressão constante, a vazão de sucção diminuiu com o acréscimo da pressão de alimentação. Para avaliar o rendimento do injetor foi desenvolvida, a partir das expressões que definem as energias piezométrica e cinética, uma equação utilizando os conceitos de potência motriz e potência útil. Para todos os diferenciais de pressão e pressão de alimentação estudados, o rendimento diminuiu com o aumento na tensão de sucção. O maior rendimento (16,28% foi verificado para pressão de alimentação de 10 m.c.a., diferencial de pressão de 2 m.c.a. e tensão de sucção de 1,43 m.c.a. e o menor (1,87% ocorreu para pressão de alimentação de 20 m.c.a., diferencial de pressão de 4 m.c.a. e tensão de sucção de 1,91 m.c.a..The hydraulic performance of a fertilizer injector (Venturi-type was evaluated. The tested injector is made of polyethylene, T-shaped, MAZZEI 1078 model, has 200 mm length, 19.6 mm inside diameter in the

  17. Uso de mezclas de azoxistrobina y triazoles para controlar enfermedades de fin de ciclo de la soja

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    Marcelo Carmona

    2011-06-01

    Full Text Available Las enfermedades de fin de ciclo de la soja (EFC, ampliamente difundidas en Argentina, afectan el rendimiento del cultivo y la calidad de la semilla cosechada. La aplicación foliar de fungicidas representa una alternativa eficiente en las actuales condiciones de cultivo (monocultivo y siembra directa. Los objetivos del presente trabajo fueron 1 determinar los agentes causales de la EFC presentes en los ensayos, 2 evaluar la disminución de rendimiento causada por las EFC y 3 valorar la eficiencia de control de mezclas de triazoles y azoxistrobina aplicados en las etapas reproductivas R3 o R5, para el control de las mismas. Se realizaron cuatro ensayos, dos en la campaña 2004/2005, y dos en la campaña 2005/2006, en Armstrong, Santa Fe, núcleo del área sojera de la Región Pampeana. Se utilizaron dos mezclas de azoxistrobina, una con cyproconazole y otra con difenoconazole, y una mezcla de los dos últimos. Los patógenos detectados fueron: Cercospora kikuchii, Colletotrichum truncatum, Septoria glycines, Glomerella glycines y Phomopsis sojae. Todos los tratamientos tuvieron mayores rendimientos que el control no tratado en todos los ensayos, con un nivel de significancia del 5%. Se concluye que, bajo las condiciones de los ensayos, con altas precipitaciones entre R1 y R5.5, los productos utilizados, controlaron eficientemente las EFC presentes.

  18. Adaptación y mejora de una herramienta de gestión de SCRUM para la gestión de los proyectos fin de carrera

    OpenAIRE

    2013-01-01

    Proyecto Fin de Carrera leído en la Universidad Rey Juan Carlos en el curso académico 2012/2013. Tutores del Proyecto: José Francisco Vélez Serrano y Ángel Sánchez Calle Este trabajo detalla la mejora de una aplicación para gestionar proyectos fin de carrera utilizando la metodología SCRUM apoyándose para ello en la Herramienta MAVEN y usando la técnica de arquitectura de software REST . Las metodologías ágiles surgieron con la idea de dinamizar la administración y gestión del des...

  19. ENSAYO: LECCIONES PARA EL POSCONFLICTO: ¿POR QUÉ EL FIN DEL CONFLICTO ARMADO EN MARÍA LA BAJA, BOLÍVAR (2006-2014 NO SUPUSO EL FIN DE LA VIOLENCIA?

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    Emy Osorio Bonacera

    2015-12-01

    Full Text Available Este artículo presenta unas reflexiones interpretativas sobre las causas que determinaron que la violencia continuara en María la Baja, Bolívar. Para ello trabaja con datos obtenidos a través de revisión bibliográfica y hemerográfica, además de recolección de testimonio de los lugareños. En ese sentido, la intención de este trabajo es aproximar a explicaciones desde lo académico que permitan entender las causas del conflicto en María la Baja, y cómo el país, en el marco de negociaciones para la paz en aras del fin del conflicto armado, puede aprender de ello.

  20. Estrategias didácticas y recomendaciones para la defensa oral de los Trabajos Fin de Grado y Fin de Máster

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    Juan Lucas Onieva López

    2016-01-01

    Full Text Available La defensa oral de los TFG y TFM será el tema que desarrollaremos en este artículo y que, con el objetivo de ayudar al alumnado y al profesorado sobre esta cuestión, analizaremos las diferentes planillas de evaluación que utilizan las universidades y las que recomiendan diferentes especialistas. También consideraremos aquellos sentimientos que ahogan a los estudiantes en este tipo de escenarios y propondremos pensamientos, ideas y estrategias para realizar una buena exposición. Para ello, ofreceremos una serie de recursos y propuestas para que los alumnos y docentes afronten con éxito la defensa de este tipo de trabajos.

  1. Un modelo conceptual para la realización del Trabajo Fin de Gradoapoyado en el uso de las TICs

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    Úrsula Faura -Martínez

    2017-01-01

    Full Text Available En el actual escenario del ámbito universitario l as herramientas de la tecnología y la comunicación (TIC están siendo empleadas para favorecer nuevos enfoques metodológicos con un matiz claramente colaborativo proporcionando una im portante proyección en los procesos de innovación educativa. Este trabajo describe una experiencia desarrollada en el ámbito universitario, cuyo objetivo es crear un modelo conceptual que refleje la influencia del trabajo colaborativo generado a través de las tutorías grupales y el uso de las TICs en el rendimiento académico en la elaboración del T rabajo Fin de Grado (TF G . Participaron estudiantes de los Grado s en Administración y Dirección de Empresas y M arketing de la Universidad de Murcia durante tres c ursos académicos . El 100% de los estudiantes que siguieron esta metodología superaron con éxito la evaluación del TFG. El 40 % obtuvo una nota superior a 9, el 23,3 % entre 8 y 9 y un 20 % superó la evaluación con matrícula de honor . Se concluye que esta form a de desarrollar el proyecto basada en las tutorías grupales, el trabajo colaborativo y el uso de TIC favorece la elaboración de l TFG , obteniendo unos resultados excelentes , produciéndose menos diferencias en las notas obtenidas y no hallándose ninguna inf luencia del sexo en dichos resultados.

  2. Avaliação de produtos de sensoriamento remoto para fins de atualização cartográfica

    OpenAIRE

    Oscar Ricardo Vergara

    1994-01-01

    A falta de documentos cartográficos atualizados indica a necessidade de desenvolver métodos de atualização de cartas topográficas que permitam reduzir o dispêndio de tempo e recursos. Considerando as vantagens derivadas para fins cartográficos este trabalho tem o objetivo de avaliar o desempenho de produtos orbitais gerados pelo INPE, no contexto de metodologias de atualização cartográfica. Para tal fim e estudado o conteúdo de informações temática de diversos grupos de dados (TM-LANDSAT em b...

  3. O Marketing de Serviços e suas Implicações para uma Organização sem Fins Lucrativos

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    Magali Costa Guimarães

    2003-05-01

    Full Text Available Este estudo restringiu-se em tentar compreender a visão de marketing de serviços dos responsáveis por uma organização sem fins lucrativos. O objetivo centrou-se em conhecer se tais pessoas conhecem quem são, o que desejam e esperam seus clientes, como vêm utilizando os conceitos de marketing e como avaliam a qualidade dos serviços executados na organização à luz da teoria de marketing. O estudo traz algumas reflexões importantes sobre a utilização do marketing de valor para as organizações sem fins que existe uma utilização de alguns elementos do marketing na organização estudada, mas de forma invertida e indutiva.

  4. Potencialidade de uso de fontes alternativas de água para fins não potáveis em uma unidade residencial

    OpenAIRE

    Peters, Madelon Rebelo

    2006-01-01

    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pos-Graduação em Engenharia Ambiental. O uso racional da água compreende o controle de desperdícios e uma re-educação de hábitos e costumes. Esta re-educação está associada ao uso de fontes alternativas como, por exemplo, os efluentes tratados gerados na própria residência e a captação de águas pluviais, em substituição a água potável para fins que não seja o consumo humano. O uso de águas de c...

  5. Fin de temporada

    OpenAIRE

    2012-01-01

    Como una jauría de leonas enjauladas que recién son liberadas, corren cientos de mujeres a buscar aquellos coloridos y centelleantes carteles que anuncian efusivos la llegada del fin de la temporada. Las tiendas hacen todo tipo de descuentos a las mercancías un poco sucias, desgastadas, arrugadas y pasadas de  moda. No son despreciadas por aquellas mujeres a las que el recorte de la mesada no les da para comprar lo que está de moda. Por  los  amplios  pasillos  ahora ...

  6. NCG69/12: Directrices de la Universidad de Granada para el desarrollo de la asignatura ???Trabajo Fin de M??ster??? de sus t??tulos de M??ster.

    OpenAIRE

    Universidad de Granada

    2013-01-01

    Las presentes directrices son de aplicaci??n al Trabajo de Fin de M??ster de los t??tulos de M??ster Universitario de la Universidad de Granada, salvo en el caso de los M??steres conjuntos, nacionales o internacionales, o que cuenten con directrices propias, como los M??steres que habilitan para el ejercicio de una profesi??n, para los que prevalecer?? el convenio correspondiente establecido entre las Universidades o la normativa espec??fica aplicable. Estas directrices se ocup...

  7. Alimento para fins especiais: ingredientes, elaboração e aglomeração Food for special needs: ingredients, development and agglomeration

    Directory of Open Access Journals (Sweden)

    Luciana Azevedo

    2011-04-01

    Full Text Available OBJETIVO: Desenvolver uma dieta enteral nutricionalmente completa, com condições ajustadas de aglomeração, visando contemplar as características físicas e químicas desejadas para esse alimento especial. MÉTODOS: Como ingredientes foram utilizados maltodextrina, óleo de canola, triglicerídios de cadeia média, goma acácia, inulina e frutooligossacarídeos, proteínas do soro de leite, isolado proteico de soja, vitaminas e minerais. Após os ajustes das quantidades e proporções dos ingredientes, a formulação foi aglomerada e submetida às análises de composição centesimal, molhabilidade, densidade aparente, atividade de água, viscosidade e cor. RESULTADOS: Obteve-se uma fórmula contendo 1kcal.mL-1, normoproteica (3,9g.100mL-1 e normolipídica (3,9g.100mL-1. Após a aglomeração da dieta, observaram-se os seguintes resultados: molhabilidade de 0,262g.s-1, densidade aparente de 0,317g.cm-3e atividade de água de 0,393. A análise de cor indicou redução da luminosidade e aumento dos parâmetros de cor a*e b*, apresentando leve variação para o vermelho e forte presença do amarelo. CONCLUSÃO: Os ingredientes empregados, e suas respectivas proporções, bem como o processo de aglomeração, possibilitaram a obtenção de um alimento para fins especiais com propriedades bioativas. O processo de aglomeração possibilitou uma dieta de fácil reconstituição e utilização através de sondas, facilitando a infusão e, consequentemente, a diminuição de intercorrências.OBJECTIVE: This study aimed to develop a nutritionally complete enteral diet, with adjusted agglomeration conditions, and determine the physical and chemical characteristics required by this special food. METHODS: The ingredients were maltodextrin, canola oil, medium-chain triglycerides, acacia gum, inulin, fructooligosaccharides, milk whey protein, soy protein isolate, vitamins and minerals. After the quantities and proportions of the ingredients were adjusted

  8. Uso regular de plantas medicinais para fins terapêuticos em famílias residentes na zona rural de Santo Antônio de Jesus – Bahia – Brasil

    Directory of Open Access Journals (Sweden)

    Raíssa Silva Santos

    2017-10-01

    Full Text Available Introdução: O uso de plantas medicinais é uma prática comum de cuidado primário nas populações em geral. Foi introduzido no Brasil, por influência das culturas indígena, africana e europeia e caracteriza-se por ser oriundo do conhecimento e da tradição popular. Objetivos: Sendo o Recôncavo da Bahia uma região de forte influência africana, o objetivo deste estudo foi investigar o uso das principais plantas medicinais e identificar seu uso pela população de um de seus municípios, valorizando o acervo cultural e o saber popular de seus moradores quanto aos benefícios que essas plantas trazem para a população. Metodologia: Para a obtenção dos dados, foi aplicado um questionário sociodemográfico, contendo questões sobre o uso de plantas para fins medicinais em chás ou xaropes com 154 entrevistados. Resultados: Desse universo de pessoas, 74,71% tinham o costume de usar remédios caseiros e 60,0% eram do gênero feminino. Os vegetais mais citados para fins medicinais foram: Lippia alba (n=71, Cymbopogon citratus (n=31, Pimpinella anisum (n=30, Peumus boldus (n=14, Plantago major e Ocimum basilicum (n=13 cada; sendo utilizados principalmente como calmante, dores em geral e contra gases. Quanto ao local de obtenção dos vegetais, os entrevistados cultivavam a planta (94,6%, pegavam do cultivo de amigos e vizinhos (1,8%, compravam na feira livre (1,8%, compravam em farmácia ou adquiriam de outros lugares (0,9%. Conclusões: Os dados evidenciam a relevância da prática do uso de plantas para manutenção da saúde dos moradores do município pesquisado, sendo parte integrante de seu contexto sociocultural. As diferentes finalidades do uso de plantas para fins medicinais mostram que mais estudos são necessários para avaliar as propriedades dessas plantas e seus efeitos no organismo humano.

  9. FIN 403 UOP Course Tutorial / fin403dotcom

    OpenAIRE

    anil10

    2015-01-01

    FIN 403 Entire Course For more course tutorials visit www.fin403.com   FIN 403 Week 1 Individual Assignment Global Finance Environment Paper FIN 403 Week 1 DQ 1 FIN 403 Week 1 DQ 2 FIN 403 Week 1 Summary FIN403 Week 2 Learning Team Assignment Investment Decision Selection Paper   FIN 403 Week 2 DQ 1 FIN 403 Week 2 DQ 2 FIN 403 Week 2 Summary FIN 403 Week 3 Learning Team Assignment Foreign Exchange and Derivatives Market Paper F...

  10. FIN 403 Uop Material-fin403dotcom

    OpenAIRE

    Sandywilliam8

    2015-01-01

    FIN 403 Entire Course For more course tutorials visit www.fin403.com   FIN 403 Week 1 Individual Assignment Global Finance Environment Paper FIN 403 Week 1 DQ 1 FIN 403 Week 1 DQ 2 FIN 403 Week 1 Summary FIN403 Week 2 Learning Team Assignment Investment Decision Selection Paper   FIN 403 Week 2 DQ 1 FIN 403 Week 2 DQ 2 FIN 403 Week 2 Summary FIN 403 Week 3 Learning Team Assignment Foreign Exchange and Derivatives Market Paper F...

  11. La importancia de los números especiales “fin de temporada” de la revista 6Toros6 como fuente de información especializada para la práctica periodística

    Directory of Open Access Journals (Sweden)

    María Verónica de Haro de San Mateo

    2010-01-01

    Full Text Available Este artículo estudia los números especiales “fin de temporada” editados por la revista 6TOROS6 con el objetivo de poner de relieve su importancia como fuente de información especializada para la práctica periodística. Los procedimientos metodológicos empleados han consistido en la descripción y el estudio de contenido de los ciento treinta y nueve ejemplares especiales publicados por este prestigioso semanario especializado en tauromaquia. Dicho estudio nos ha permitido constatar la objetividad de los apéndices estadísticos contenidos en estos anuarios así como el grado de especialización de los profesionales que los confeccionan. Y entre otros, estos valores nos han permitido concluir que los especiales “fin de temporada” de la revista 6TOROS6 son una válida y muy útil herramienta documental para el ejercicio de la actividad periodística.

  12. Shark's Fin Soup

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Ingredients: 250g semi-finished shark's fin (removed of bone, skin and dipped in water), 100g ham, 100g chicken, 50g pork shoulder, 50g dried scallops, 100g bean sprouts, salt and MSG (optional). Method: 1. Scald the shark's fin in boiling water. 2. Fill a pot with water and add the chicken, pork and most of the

  13. Tráfico de Pessoas para fins de exploração do trabalho na cidade de São Paulo Human trafficking for labour exploitation in the city of São Paulo

    Directory of Open Access Journals (Sweden)

    Paulo Illes

    2008-12-01

    Full Text Available Este artigo busca contextualizar, em linhas gerais, o fluxo de imigrantes bolivianos para fins de trabalho nas oficinas de costura da cidade de São Paulo, demonstrando a interface dessa imigração com o tráfico de migrantes e o tráfico de pessoas. Por meio de depoimentos, são apresentadas as recorrentes dificuldades enfrentadas pelas trabalhadoras imigrantes.This article seeks to contextualize, along general lines, the Bolivian migratory flow towards sweatshops in the city of São Paulo, showing the interaction between this migratory flow, migrant smuggling and human trafficking. The most frequent problems faced by the migrant women are presented in testimonials.

  14. Effect of Water Vapor During Secondary Cooling on Hot Shortness in Fe-Cu-Ni-Sn-Si Alloys

    Science.gov (United States)

    Sampson, Erica; Sridhar, Seetharaman

    2014-10-01

    Residual Cu in recycled steel scrap can cause hot shortness when the iron matrix is oxidized. Hot shortness can occur directly after the solid steel is formed from continuous casting as the steel undergoes a cooling process known as secondary cooling where water is first sprayed on the surface to promote cooling. This is followed by a radiant cooling stage where the steel is cooled in air to room temperature. This investigation examines the roles of water vapor, Si content, temperature, and the presence of Sn in a Fe-0.2 wt pct Cu-0.05 wt pct Ni alloy on oxidation, separated Cu and Cu induced-hot shortness during simulations of the secondary cooling process. The secondary cooling from 1473 K (1200 °C) resulted in a slight increase in liquid quantity and grain boundary penetration as compared to the isothermal heating cycles at 1423 K (1150 °C) due to the higher temperatures experienced in the non-isothermal cycle. The addition of water vapor increased the sample oxidation as compared to samples processed in dry atmospheres due to increased scale adherence, scale plasticity, and inward transport of oxygen. The increase in weight gain of the wet atmosphere increased the liquid formation at the interface in the non-Si containing alloys. The secondary cooling cycle with water vapor and the effect of Sn lead to the formation of many small pools of Cu-rich liquid embedded within the surface of the metal due to the Sn allowing for increased grain boundary decohesion and the water vapor allowing for oxidation within liquid-penetrated grain boundaries. The presence of Si increased the amount of occlusion of Cu and Fe, significantly decreasing the quantity of liquid at the interface and the amount of grain boundary penetration.

  15. Descrição de uma ferramenta digital e de um ambiente virtual para fins de segunda opinião em oftalmologia

    Directory of Open Access Journals (Sweden)

    Pennella Alessandro Dantas

    2003-01-01

    Full Text Available OBJETIVOS: Idealizar, desenvolver e verificar a funcionalidade um sistema de teleoftalmologia para diagnóstico remoto em casos clínicos. MÉTODOS: Descrever o funcionamento e utilização do sistema, sua capacidade de captura, arquivamento e envio de imagens via internet, e de um domínio virtual voltado ao telediagnóstico, aconselhamento ou segunda opinião. RESULTADOS: Foram definidos os requisitos básicos, detalhes de programação e de funcionamento de um programa de captura de imagens. O funcionamento do mesmo acoplado a uma placa de captura de imagens foi realizado com sucesso, bem como a criação, na internet, de um domínio médico-oftalmológico. CONCLUSÃO: Os resultados preliminares permitiram a avaliação de um sistema misto para o suporte médico em nosso meio. Os instrumentos diagnósticos disponíveis bem como suas conexões com a rede foram satisfatórias e suficientes para viabilizar um estudo piloto bem su-cedido. O sistema revelou-se potencialmente adequado para o telediagnóstico e segunda opinião. O método necessita de testes clínicos e compa-ração com métodos diagnósticos tradicionais para comprovar a sua eficácia.

  16. Estrategias Pedagógicas para Desarrollar las Habilidades Metacognitivas del Alumno de Instrumento con el Fin de Maximizar la Eficacia de sus Prácticas Instrumentales

    Directory of Open Access Journals (Sweden)

    Malinalli Peral García

    2014-07-01

    Full Text Available Este artículo trata sobre los conocimientos y estrategias pedagógicas que se pueden aplicar para desarrollar las habilidades metacognitivas del alumno de instrumento. Primero, se explican los distintos componentes de la metacognición que el profesor de instrumento debe integrar a su pedagogía para guiar a su alumnado en su desarrollo metacognitivo. A continuación, se presentan los modos de intervención pedagógicos a privilegiar para iniciar al alumno de un instrumento en un proceso metacognitivo. Finalmente, se proponen dos estrategias pedagógicas provenientes de las ciencias de la educación diseñadas para desarrollar las habilidades metacognitivas de los estudiantes, las cuales han sido adaptadas a las necesidades específicas de la práctica instrumental. Estas herramientas ofrecen al músico-pedagogo referencias para guiar el desarrollo de las habilidades metacognitivas de su alumnado.

  17. Técnicas de utilização de dicionário como material didático na aula de LE para fins específicos

    Directory of Open Access Journals (Sweden)

    Camila Höfling

    2006-01-01

    Full Text Available Este artigo apresenta uma metodologia de trabalho relacionado ao uso do dicionário como material didático na aula de língua estrangeira com fins específicos, em atividades como desenvolvimento de vocabulário, gramática, pronúncia, uso de língua, cultura, leitura e interpretação de texto. Com certas técnicas, os professores podem aproveitar esse material em suas aulas e orientar seus alunos sobre qual dicionário adquirir e como empregá-lo de maneira eficiente. Oferecemos algumas sugestões de atividades para serem realizadas com o dicionário, seja em aulas para alunos particulares ou em cursos profissionalizantes em áreas específicas.This paper presents a methodology related to the use of dictionary as a pedagogic resource in the foreign language for specific purposes class, in activities developing vocabulary, grammar, pronunciation, language use, culture, and reading comprehension. By using some techniques, teachers can benefit from this resource in class and instruct their students about how to choose and use a dictionary properly. We offer some suggestions of activities to be performed both in private classes (one-to-one and with groups of professionals with specific purposes.

  18. APLICACIÓN INFORMÁTICA PARA LA EVALUACIÓN DE RIESGOS INDUSTRIALES A FIN DE DETERMINAR UN INDICADOR DE RIESGOS EN EMPRESAS VENEZOLANAS

    Directory of Open Access Journals (Sweden)

    Liliana Manduca Alvarado

    2008-11-01

    Full Text Available

    Con la aplicación del sistema para la evaluación de riesgos industriales (SIPERI descrito en el trabajo, la autora logra facilitar la evaluación del indicador de riesgos de las empresas. La metodología propuesta obliga a que las empresas cumplan los pasos esenciales de control de gestión en cuanto a planificar, organizar, dirigir y controlar los riesgos industriales. La disminución del indicador de riesgos industriales (IRI, es un incentivo económico para las entidades y exige el mejoramiento continuo de la seguridad en el trabajo a partir del control sistemático de las condiciones de trabajo.

  19. ANÁLISE AMBIENTAL E O SISTEMA HIDROGRÁFICO DO CÓRREGO DO PORTO, TRÊS LAGOAS (MS) PARA FINS DE PLANEJAMENTO AMBIENTAL

    OpenAIRE

    Luziane Bartolini Albuquerque; Arnaldo Yoso Sakamoto

    2015-01-01

    Este trabalho tem por objetivo, uma análise ambiental e descrição do sistema hidrográfico do córrego do Porto – Três Lagoas (MS) como subsídio ao planejamento ambiental, utilizando técnicas de sensoriamento remoto e geoprocessamento, a fim de verificar as possíveis mudanças ocorridas nos anos de 2001 e 2008. Para tal estudo, foram utilizadas imagens de satélite Landsat +5 TM, juntamente com a carta topográfica para identificação do sistema hidrográfico e das transformações ocorridas. Através ...

  20. La novela como fuente para la Historia Contemporánea : "El árbol de la ciencia" de Pío Baroja y la crisis de fin de siglo en España

    Directory of Open Access Journals (Sweden)

    Francisco Fuster García

    2011-01-01

    Full Text Available El objetivo de este artículo es defender el uso de la novela como fuente para el historiador y, más concretamente, para la historia contemporánea. En una primera parte del trabajo, mi propósito ha sido el de ofrecer una visión general del debate historiográfico sobre la utilidad de la literatura para la escritura de la historia, dando algunos de los argumentos que la historiografía —especialmente aquellos historiadores que más han practicado la llamada «historia cultural»— ha aportado como razones que justifican la condición de la literatura como documento útil para el historiador. En un segunda parte del trabajo, he centrado mi atención en las novelas de Pío Baroja como posibles fuentes que el historiador puede usar para estudiar la crisis de fin de siglo en España; de ellas, he tomado el ejemplo del El árbol de la ciencia como novela paradigmática de Baroja que nos puede ser útil para estudiar el período de la historia contemporánea de España que abarca la última década del siglo XIX y las dos primeras décadas del siglo XX.The aim of this paper is to defend the use of the novel as a source for the historian, for the Contemporary History to be precise. In the first part of the paper, my purpose has been to provide with an overview of the historiographical debate about the usefulness of literature for the writing of history, giving some of the arguments historiography —specially those historians who had concentrated on the so-called «cultural history»— has provided as reasons to justify the condition of literature as a useful document for the historian. In the second part of this work, I have paid more attention to Pío Baroja’s novels as possible sources to the study of the end-of-century crisis in Spain; from among these novels, I take Pío Baroja’s El árbol de la ciencia as a paradigmatic novel which could be useful for us to the study of the period of Spanish contemporary history which covers from the

  1. Nitrogen and age on the quality of elephant grass for agroenergy purpose grown in OxisolNitrogênio e idade de corte na qualidade da biomassa de capimelefante para fins agroenergéticos cultivado em Latossolo

    Directory of Open Access Journals (Sweden)

    Rilner Alves Flores

    2013-03-01

    Full Text Available Nowadays one of the major challenge for research is the production of alternative agrifuels energy material derived from plant biomass. Allied to this, the proper management of nitrogen, becomes fundamental for productivity gains and improvement in quality of elephant grass biomass. Thus, the objective was to evaluate the effect of nitrogen fertilization and plant age effect on the quality of elephant grass biomass for energy purposes. The experiment was performed with genotype Paraíso, grown in a dystrophic Oxisol in the southern state of Tocantins. The design was randomized blocks with subdivided plots, situating plots as nitrogen rates (0, 50, 100 and 150 kg ha-1 and the subplots cutting age (120, 150 and 180 days after planting four replicates. We evaluated the relationship carbon/nitrogen (C:N and leaf/stem (L:S, levels of neutral detergent fiber (NDF and ash contents in dry biomass produced. The application of nitrogen increased by 12% to C:N ratio of the plant. The advanced age of cut forage was increased 9% in the C:N plant, however, decreased by 12 and 14% levels of ash produced in the stem and leaves, respectively. The production of elephant grass for agrifuels is feasible with management system proposed, quality characteristics desirable, such as high C:N ratio, above 40% and higt fiber content, above 50%. Atualmente um dos grandes desafios para a pesquisa de agroenergia é a produção de material energético alternativo derivado da biomassa vegetal. Aliado a isso, o manejo adequado do nitrogênio, torna-se fundamental para obter ganhos de produtividade e melhoria na qualidade da biomassa de capim-elefante. Desse modo, objetivou-se avaliar o efeito da adubação nitrogenada e da idade de corte do capimelefante (Pennisetum purpureum na qualidade da biomassa da forrageira para fins agroenergéticos. O experimento foi realizado com o genótipo Paraíso, cultivado em um Latossolo Vermelho Amarelo distrófico no sul do Estado de

  2. Hegel y el fin del arte

    Directory of Open Access Journals (Sweden)

    Óscar Cubo Ugarte

    2010-03-01

    Full Text Available Uno de los puntos de mayor interés del pensamiento estético de Hegel procede de sus Lecciones de estética, y es aquel que afirma y tematiza el fin del arte. Para entender el sentido y el alcance de esta idea, presentamos en este trabajo el modo como Hegel trata el problema del arte dentro de su filosofía especulativa y en especial en sus Lecciones de Estética. Por medio de este proceso de contextualización rastreamos finalmente las distintas interpretaciones que se han producido en nuestros días acerca de la provocativa tesis del fin del arte y dejamos planteada también la cuestión del lugar que ocupa o puede ocupar el arte después del mencionado fin del arte.

  3. Hegel y el fin del arte

    Directory of Open Access Journals (Sweden)

    Óscar Cubo Ugarte

    2010-03-01

    Full Text Available Uno de los puntos de mayor interés del pensamiento estético de Hegel procede de sus Lecciones de estética, y es aquel que afirma y tematiza el fin del arte. Para entender el sentido y el alcance de esta idea, presentamos en este trabajo el modo como Hegel trata el problema del arte dentro de su filosofía especulativa y en especial en sus Lecciones de Estética. Por medio de este proceso de contextualización rastreamos finalmente las distintas interpretaciones que se han producido en nuestros días acerca de la provocativa tesis del fin del arte y dejamos planteada también la cuestión del lugar que ocupa o puede ocupar el arte después del mencionado fin del arte.

  4. Historico, usos oficiais e avaliação da redução de escala de analise volumetrica para fins didaticos

    OpenAIRE

    Juliana Terra

    2004-01-01

    Resumo: Os métodos ditos clássicos representaram um papel fundamental no desenvolvimento da Química. Durante os séculos XVIII e XIX eram praticamente os únicos processos usados nas análises químicas e hoje, mesmo com o desenvolvimento tecnológico, têm sua presença constante. Depois de realizada uma extensa pesquisa bibliográfica, apresenta-se uma descrição do desenvolvimento da volumetria que permite contextualizar importantes aspectos científicos de relevância para abordagens didáticas de di...

  5. Viabilidade técnica do uso de receptores GPS de navegação para fins de amostragem sistemática de solo

    Directory of Open Access Journals (Sweden)

    Maurício Sonda Tonello

    2011-04-01

    Full Text Available Os receptores de navegação do sistema de posicionamento global (GPS, comumente utilizados pelo setor agrícola, em geral, apresentam precisão posicional < 10,0 m. Em uma amostragem sistemática de solos, as subamostras deverão ser coletadas num raio não superior a 3 m do ponto central georreferenciado. A presente nota técnica visou confrontar a precisão e exatidão desse tipo de equipamento com a necessidade exigida em amostragem sistematizada de solo. Uma área com aproximadamente 17 ha, no campus I da Universidade de Passo Fundo, foi levantada com três receptores GPS de navegação e Estação Total-ET (controle. Pontos centrais de quadrículas de 2 ha, gerados pelo programa Campeiro®, foram locados no campo com os mesmos equipamentos. Sobre esses pontos, materializados no campo, foram novamente tomadas as suas coordenadas, com auxílio da estação total. Assim, as coordenadas X e Y foram submetidas à ANOVA, confrontando-se as médias obtidas pela ET com as dos receptores de GPS pela diferença honesta significativa do teste de Tukey (p < 0,01. Quanto à exatidão, calcularam-se, por Pitágoras, as distâncias lineares entre os pontos gerados pelos GPS e pela ET, assumindo-se não exatas quando ultrapassaram os 3 m de raio preconizado pelo Manual de Adubação e Calagem do Rio Grande do Sul e de Santa Catariana para coleta de solo. A exatidão das coordenadas dos receptores GPS variou de -10 m a +3 m para X e de -4 m a +7 m para Y. Apenas um ponto central dos oito locados com os receptores de GPS de navegação no centro das quadrículas apresentou exatidão compatível com a exigida pela prática. Isso indica que esse tipo de equipamento, com baixa precisão e exatidão, não deve ser utilizado para amostragem sistematizada de solos.

  6. Epigenética y el fin del debate natura vs nurtura: implicaciones para la psicología clínica

    OpenAIRE

    Torres Caldera, Rocio

    2016-01-01

    [ES]Desde hace unas décadas, la epigenética se ha convertido en un campo emergente y prometedor a la hora de unificar las aportaciones de las distintas disciplinas de la salud. En el presente trabajo se expondrá una revisión de la creciente importancia de los mecanismos epigenéticos en las interacciones entre genes y ambiente implicadas en la etiología de diversos trastornos mentales, dentro del marco teórico de la psicología evolucionaria del desarrollo; así como sus potenciales usos para la...

  7. Otimização de técnicas de captura, manutenção e transporte de animais marinhos para fins ornamentais

    OpenAIRE

    Morais, Hugo Arantes de

    2014-01-01

    A Flying Sharks é uma empresa portuguesa fundada em 2006, que se dedica ao meio marinho, exercendo atividades na área da captura de animais marinhos, consultoria, conservação e educação. A empresa desenvolve atividade nos quatro cantos do mundo, tendo já realizado entregas de pequenas e grandes dimensões em vários países, começando em Portugal e Espanha, alargando horizontes para países como Alemanha, Polónia, Turquia, Japão, Dubai, Estados Unidos, entre outros transportando-as por terra, ar ...

  8. A parceria entre Ciência da Informação e responsabilidade social universitária para fins de inclusão social

    Directory of Open Access Journals (Sweden)

    André Anderson Cavalcante Felipe

    2014-02-01

    Full Text Available O artigo apresenta o conceito, surgimento e aplicabilidade da responsabilidade social universitária (RSU, trazendo exemplos de sua utilização vinculada à extensão universitária, que se demonstra ser uma parceria essencial para oportunizar a inclusão social. Como objetivo discute a atuação da Ciência da Informação (CI juntamente com a RSU, e analisa um projeto de extensão que relaciona ambas, intitulado “Biblioterapia, informação e terceira idade: a função terapêutica da leitura em idosos asilados na cidade de Cuité – PB como ferramenta de inclusão social da Universidade Federal de Campina Grande (UFCG”. Os resultados mostram que a parceria entre CI e RSU promove impactos positivos junto ao público asilado na cidade de Cuité, visto que, a ação de extensão analisada comprovou que a leitura é um importante instrumento de afeto e de sensibilização, que atingiu todos os participantes, contribuindo para a inserção destes no meio social de Campina Grande.

  9. CARACTERIZAÇÃO MINERALÓGICA PARA FINS TURÍSTICOS DAS AREIAS DE PONTA NEGRA – NATAL/RN/BRASIL

    Directory of Open Access Journals (Sweden)

    José Yvan Pereira Leite

    2014-07-01

    Full Text Available A praia de Ponta Negra esta localizada em Natal, capital do Rio Grande do Norte, sendo esta o principal cartão postal do Estado que é caracterizado por uma grande duna margeada pela Mata Atlântica. Com o objetivo de gerar produtos voltados para desenvolvimento do turismo, associando temas da área mineral foi coletada amostra próximo ao Morro do Careca, seguida de classificação granulométrica, separação em meio denso e identificação mineralógica com técnicas de microscopia ótica e em MEV. Em seguida, as imagens foram tratadas e gerados produtos associando os minerais identificados (quarzto, epidoto, rutilo, magnetita, titanita, ilmenita, zirconita na areia de praia com a paisagem da região. As imagens deverão ser utilizadas na geração de produtos, tais como cartões postais, pôsteres, camisetas, bateias, folders, livros, entre outros. Este trabalho elevará a divulgação e valoração da área mineral, bem como fomentará empreendimentos voltados para a divulgação científica.

  10. Formação de uma estratégia diplomática: relendo Sun Tzu para fins menos belicosos

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Almeida

    2011-03-01

    Full Text Available Releitura introdutória do clássico Arte da Guerra, de Sun Tzu, adaptando seus argumentos para o objetivo de formulação de uma estratégia diplomática, necessariamente distinta da concepção militar que presidiu à sua elaboração.

  11. Amostragem em cana-de-açúcar, para fins de analise foliar Sampling leaves for leaf analysis studies in sugar cane

    Directory of Open Access Journals (Sweden)

    J. Romano Gallo

    1962-01-01

    Full Text Available Êste trabalho foi realizado com o objetivo de determinar, a partir da experimentação local, um sistema adequado de amostragem de fôlhas, como base para posteriores estudos que visem estabelecer os níveis de nutrição para a cana-de-açúcar, através da análise foliar. A amostragem foi efetuada na cana planta, variedade CB. 41/76, num experimento fatorial reduzido a NPK 2³ e obedeceu ao seguinte critério: foram colhidas fôlhas de quatro posições, definidas pelo sistema de Kuijper (fôlha +1, + 2, +3, e +4; para as fôlhas de uma mesma posição foram separadas três partes (lâmina com nervura, lâmina sem nervura, e bainha; as amostras foram retiradas em seis idades da planta (4, 5, 6, 7, 8 e 9 meses. A variação dos teores dos principais constituintes minerais nos tecidos colhidos, em cada época, foi examinada estatísticamente, em função da adubação química usada, considerados seus efeitos na produção de cana. Pelos resultados obtidos e levando em conta o trabalho analítico no laboratório e simplificação de amostragem, é indicada a seleção da fôlha de posição +3, aos 4 e 8-9 meses de idade da planta, para determinar nos 20 cm centrais da lâmina, excluída a nervura principal, os elementos nitrogênio, fósforo, potássio, cálcio e magnésio.A group of 576 leaf samples of cane, variety CB.41/76. was collected form a 2³ NPK factorial experiment in order to determine the most raliable sampling technique as a basis for the local conditions of the State of São Paulo. The selection of tissues for analysis was carried out on the plantation with respect to the age at sampling time (4, 5. 6, 7, 8 and 9 months in age, leaf part (blades, blades with midribs removed, and sheaths, and leaf position (leaves +1, +2, +3 and +4. This included the four youngest visible-dewlap leaves on the cane top, numbered according to the system of Kuijper. After each tissue was analyzed for N, P, K, Ca and Mg, the data were examined

  12. Avaliação da degradação térmica e fotooxidativa do ABS para fins de reciclagem

    Directory of Open Access Journals (Sweden)

    Sanchez Elisabete Maria Saraiva

    2003-01-01

    Full Text Available Este trabalho tem como objetivo avaliar a degradação térmica e fotooxidativa do terpolímero poli (acrilonitrila-butadieno-estireno, ABS, utilizado em componentes internos de automóveis. Corpos de prova de ABS moldados por injeção foram submetidos ao envelhecimento térmico, segundo a norma ASTM D794, e ao envelhecimento fotooxidativo segundo as normas ASTM G24 e G53. As amostras envelhecidas foram submetidas às análises dinâmico-mecânica, e microscópicas por microscopia de força atômica no modo não contato. Os resultados mostraram que as transições, tanto da fase vítrea quanto da fase elastomérica na superfície do ABS, são afetadas pela degradação. As áreas dos picos das curvas de módulo de perda em função da temperatura relativos às transições vítreas do ABS foram correlacionadas ao alongamento na ruptura, em função do tempo e tipo de envelhecimento. As propriedades mecânicas são influenciadas de forma mais acentuada pela extensão da degradação da matriz. O método de envelhecimento ASTM G24 mostrou-se mais agressivo que o G53, seja para a fase BR ou para a fase SAN. As imagens microscópicas mostraram que os diferentes envelhecimentos provocaram diferentes variações na rugosidade das superfícies. Amostras fotooxidadas, com perda de alongamento maior que 50%, foram reprocessadas e mostraram uma recuperação superior a 90% nessa propriedade.

  13. AVALIAÇÃO QUÍMICA DE CORRETIVOS DE ACIDEZ PARA FINS AGRÍCOLAS: UMA NOVA PROPOSIÇÃO

    Directory of Open Access Journals (Sweden)

    J.C. ALCARDE

    1996-05-01

    Full Text Available Foi estudado o efeito da granulometria nas determinações do poder de neutralização, do cálcio e do magnésio de corretivos da acidez de solos. É sugerido um procedimento alternativo simplificado para avaliação química desses corretivos, fundamentado em: (1 uso de amostras moídas e passadas em peneira nº 100-ABNT; (2 emprego de um método de determinação do poder de neutralização através da titulação com indicador, de uma alíquota de um extrato diluído, e (3 determinação do cálcio e do magnésio no mesmo extrato obtido para a determinação do poder de neutralização. Esses procedimentos, além de simplificarem a metodologia analítica, permitiriam uma interpretação agronômica mais adequada.The effects of particle size on the determination of the neutralizing value, calcium and magnesium, were studied for agricultural liming materials. An alternative and simplified procedure is suggested for the chemical evaluation of amendments, based on: (1 the use of ground samples passed through sieve number 100-ABNT, (2 the determination of the neutralizing value by titration with an indicator using a diluted extract, and (3 the determination of calcium and magnesium in the same extract used for the determination of the neutralizing value. These procedures simplify the analytical methodology for evaluation of agricultural liming materials, and allow a more suitable agronomic interpretation.

  14. Uma cidade criativa de tipo relacional: Para uma cartografia das ligações em rede entre os setores público, privado e sem fins lucrativos nas indústrias criativas

    Directory of Open Access Journals (Sweden)

    Roberta Comunian

    2013-09-01

    Full Text Available Tem sido grande a atenção recentemente dada ao papel que as artes, a cultura e a criatividade podem desempenhar na requalificação e desenvolvimento das cidades. Neste quadro, o presente artigo utiliza a análise de redes sociais (ARS com vista a investigar não só o impacto decorrente da requalificação física, mas também o papel desempenhado pelas redes de conhecimento e de apoio no contexto da economia criativa urbana. Embora o método não seja novo, a sua adoção pelos estudiosos deste tema tem sido pouco significativa. Tomando como exemplo o estudo levado a cabo em Newcastle‑Gateshead e na região do Nordeste da Inglaterra, que investigou as redes e as relações existentes entre as indústrias criativas, o trabalho que aqui se apresenta visa trazer a este debate um contributo metodológico e teórico. Os resultados evidenciam a importância das redes de conhecimento e de apoio no campo das indústrias criativas, apontando para a necessidade de adotar uma abordagem baseada nas redes pessoais para compreender cabalmente quem são os atores‑chave de um dado sistema local e de que modo eles interagem. Longe de restringir ao plano empresarial as interações baseadas no conhecimento, o artigo mostra, além disso, a importância das interligações com os setores público e sem fins lucrativos.

  15. Fin Distance Effect at Tube-Fin Heat Exchanger

    Science.gov (United States)

    Lemfeld, F.; Muller, M.; Frana, K.

    2013-04-01

    Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  16. Fin Distance Effect at Tube-Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Frana K.

    2013-04-01

    Full Text Available Article deals with numerical simulation of the Tube-Fin heat exchanger. Several distances between fins are examined with intence of increasing the cooling output of the heat exchanger. Geometrical model consists of set of 2 fins with input and output area. Calculations covers the area of the gap from 2.25 mm to 4 mm with new fin geometry. For the numerical silumation was used software Ansys Fluent.

  17. Esplanada: cultivar de cenoura de verão para fins de processamento Esplanada: a new tropical carrot variety suitable for minimum processing

    Directory of Open Access Journals (Sweden)

    Jairo V. Vieira

    2005-07-01

    Full Text Available A cenoura é uma das hortaliças tradicionais mais consumidas no Brasil. Entretanto, o consumo de mini cenouras tipo "cenourete" obtidas via processamento mínimo ainda é muito pequeno no país. Isto se deve possivelmente ao restrito conhecimento da tecnologia de produção deste produto e da dificuldade em se obter matéria prima de qualidade e com regularidade, especialmente no período de verão. As raízes das principais cultivares utilizadas no Brasil não apresentam características de qualidade como coloração, formato e tamanho adequados para possibilitar máximo rendimento industrial. Neste contexto, foi desenvolvida a cultivar de polinização aberta "Esplanada", que apresenta boa adaptação às condições edafoclimáticas brasileiras, possui alta resistência à queima-das-folhas, baixa incidência de florescimento precoce no verão e resistência moderada a nematóides formadores de galhas. Estas características viabilizam seu cultivo em qualquer época do ano, nas principais regiões de produção. As raízes são compridas, finas e apresentam coloração uniforme, características estas adequadas para o processamento mínimo visando a produção de cenourete. Esta cultivar poderá ocupar posição estratégica na cadeia produtiva de cenoura, uma vez que vai possibilitar a produção de mini cenouras durante todo o ano em qualquer região do país.Carrot is one of the most consumed vegetables in Brazil. However, the consumption of "baby carrots", obtained by minimally processed roots, is still very low in the country, due to lack of processing technology knowledge and the low amount of minimally processed carrots produced in Brazil as a consequence of the low industrial productivity. The carrot varieties currently employed in minimum processing have as major disadvantages a series of low quality attributes including inadequate root shape and size which precludes reaching the maximum industrial yield. In this context, Embrapa

  18. Extending Fin Concept for a 105-mm Fin Stabilized Projectile

    Science.gov (United States)

    2011-04-01

    more demand for precision guided munitions. The complexity of combat in urban settings requires novel fighting techniques and strategies; driving...fins in the stowed configuration deployment, the fin hubs (6) will rotate forward until they contact the spacer (3). At this point, the fins (7) cock

  19. ¿El fin de la frontera? Reflexiones desde el caso colombiano para una nueva construcción social de la naturaleza proiegida.

    Directory of Open Access Journals (Sweden)

    Germán I. Andrade .

    2009-04-01

    Full Text Available Biólogo, Universidad de los Andes, Bogotá, Colombia; M.Sc. en Environmental Studies, Yale University, School of Forestry, Estados Unidos. Entre sus publicaciones se encuentra: Conducir el cambio. Hacia un modelo ecosistémico en la conservación del Sistema Nacional de Áreas Naturales Protegidas de Colombia. En Gobernabilidad, Instituciones y Medio Ambiente en Colombia, ed. Manuel Rodríguez, 477-523. Bogotá: Foro Nacional Ambiental, 2008; En el Sistema de Parques Nacionales de Colombia. Conficto socio ambiental prolongado, e incertidumbre de conservación. En Trilogía Incompleta. Medio Ambiente, Desarrollo y Paz. Experiencia al cierre del Programa Ambiental apoyado por GTZ, 293-304, Bogotá, 2006; Más allá de la biodiversidad. Categorías y objetivos para el Sistema Nacional de Áreas Protegidas con base en una valoración sistémica de la naturaleza. En Bases técnicas y legales de la Política de Participación Social en la Conservación, 255-295. Bogotá: Parques Nacionales Naturales de Colombia; Science and Society at the World Parks Congress. Conservation Biology. 19 (1: 1-2, ambas del 2005. Actualmente se desempeña como profesor de la Facultad de Administración de la Universidad de los Andes, Bogotá, Colombia. Correo electrónico: gandrade@uniandes.edu.co

  20. Caracterização físico-química e microbiológica do esgoto da UEPB com proposta de tratamento para fins de reuso

    Directory of Open Access Journals (Sweden)

    M. U. Sousa

    2015-12-01

    Full Text Available Nos últimos anos, a preocupação com as questões ambientais vem sendo bastante discutidas, onde merece destaque, o descarte indevido do esgoto doméstico no meio ambiente, portanto o presente estudo objetivou realizar a caracterização físico-química e microbiológica do esgoto descartado no solo, no Centro de Ciências e Tecnologia da Universidade Estadual da Paraíba, campus de Campina Grande – PB. Para tanto foram desenvolvidas análises físico-químicas, tais como pH, Fósforo Total, DBO, DQO, Nitratos, Nitritos, Nitrogênio Amoniacal, Orto-Fosfatos e Alcalinidade, bem como análise microbiológica (coliformes. Observou-se que o efluente na unidade em questão não recebe tratamento para seu descarte, sendo identificadas características físico-químicas e microbiológicas de esgoto in natura. Faz-se necessário desta forma, investimentos em análises periódicas para assim realizar um tratamento adequado ao efluente visando-se reduzir os riscos ambientais e de saúde pública. Após os resultados das análises, foi proposto, além do tratamento preliminar, um tratamento biológico para o efluente, do tipo, lagoa facultativa primária seguida de duas lagoas de maturação, onde a eficiência do tratamento nos parâmetros analisados se enquadra aos padrões estabelecidos pelo CONAMA 430/2011, na qual o efluente pós - tratado poderia ser reutilizado para fins menos nobres, destinando a água potável para atividades que requerem uma qualidade melhor.Physicochemical and microbiological characterization of wasterwater of the UEPB with proposed of treatment for reuse purposesAbstract: In recent years, concern about environmental issues has been widely discussed, which deserves mention the improper disposal of domestic sewage into the environment, so this study aimed to perform the physicochemical and microbiological sewage discarded the soil, in the Science and Technology Center of the State University of Paraiba, campus of Campina

  1. Proposta de utilização da microestrutura de pelos-guarda para fins de estudos forenses e no controle de qualidade de alimentos

    Directory of Open Access Journals (Sweden)

    Fabiana Silveira

    2013-10-01

    Full Text Available A identificação de mamíferos através das características microscópicas de seus pelos é possível com a utilização de várias técnicas tais como a análise dos padrões microestruturais encontrados nas escamas cuticulares e células medulares dos pelos-guarda. Tais técnicas utilizadas comumente no reconhecimento espécie específica podem também ser ferramenta em estudos forenses e de controle de qualidade de alimentos. Neste sentido, este estudo tem como objetivo a identificação microscópica de pelos-guarda de espécies domiciliares e peridomiciliares que possam ter ocorrência em locais de crime ou como contaminantes de alimentos. Assim, foram utilizados pelos-guardas coletados de coleções zoológicas e de espécimes vivos de gambás-de-orelha-preta e gambá-de-orelha-branca, camundongo, ratazana-de-casa, ratazana-de-esgoto, algumas espécies de morcegos, gato-doméstico, cão-doméstico e a espécie humana. Por meio do método utilizado, foram encontrados quatro padrões de cutícula: conoidal, ondeada, folidácea e losângica, sendo que a ondeada apresentou as variações lisa e ornamentada nas bordas das escamas. Para a medula foram encontrados seis padrões: ausente, presente unisseriada e presente multisseriada crivada, trabecular, matricial e alveolar. Com os resultados obtidos foi possível diferenciar todas as espécies abordadas através da análise dos padrões microestruturais de seus pelos-guarda, sendo os resultados apresentados em uma chave dicotômica ilustrada por fotomicrografias dos padrões.

  2. Geoprocessamento na geração de cartas temáticas para fins de planejamento ambiental na microbacia do córrego Comur em Botucatu-SP

    Directory of Open Access Journals (Sweden)

    Sergio Campos

    2011-04-01

    Full Text Available

    O levantamento do uso da terra numa dada região é fundamental para a compreensão dos padrões de organização daquele determinado espaço. O presente trabalho teve como objetivo avaliar o geoprocessamento aplicado na geração de cartas temáticas para fins de planejamento ambiental, através do Sistema de Informações Geográficas Idrisi Andes 15.0. A microbacia do Córrego Comur está situada no município de Botucatu (SP e entre as coordenadas geográficas: latitude 22º 44’ 42” a 22º 48’ 12” S e longitudes 48º 23’ 04” a 48º 25’ 54”  W Gr, com uma área de 1458,4ha. Os resultados permitiu inferir que as classes de declive de 0 a 3% e de 3 a 6% ocorrentes na microbacia representam mais de 67% da área e as de 0 a 20% predominaram em mais de 80% da microbacia. As áreas com relevo suavemente ondulado (3 a 6% foram as mais representativas (36,92%. A unidade de solo Latossolo Vermelho Distroférrico ocorreu em mais de 45% da área. O SIG mostrou-se uma excelente ferramenta imprescindível, pois facilita e agiliza a obtenção dos dados, além de permitir seu armazenamento, que poderão ser utilizados para outras análises em futuros planejamentos geoambientais.

  3. Uso de composiciones que contienen menadiona y/o alguno(s) de sus derivados hidrosolubles para bioestimular los mecanismos naturales de defensa de las plantas, a fin de desarrollar sus propiedades antialimentarias frente a los ataques de patógenos y plagas

    OpenAIRE

    Borges Pérez, Andrés Antonio; Borges, Andrés A.

    2006-01-01

    Uso de composiciones que contienen menadiona y/o alguno( s) de sus derivados hidrosolubles para bioestimular los mecanismos naturales de defensa de las plantas, a fin de desarrollar sus propiedades antialimentarias frente a los ataques de patógenos y plagas. Estas soluciones acuosas pueden contener indistinta o conjuntamente como componentes activos Vitamina K3, derivados suyos solubles [preferentemente menadiona sodio bisulfito ó MSB] o escasamente solubles [preferent...

  4. Concept Maps powered by computer software: a strategy for enhancing reading comprehension in English for Specific Purposes Mapas conceituais mediados pelo computador: uma estratégia para aumentar o nível de compreensão escrita em inglês para fins específicos

    Directory of Open Access Journals (Sweden)

    Reinildes Dias

    2011-01-01

    Full Text Available This paper focuses on the procedures of an action-research (STRINGER, 2007 that was conducted with undergraduates enrolled in an ESP course at Faculdade de Letras (UFMG. The impelling drive was the creation of a means to solve an educational problem, namely, the enhancement of students' reading comprehension of texts in English for academic purposes. The problem-solving process involved the use of concept maps (NOVAK; CAÑAS, 2008 powered by the CMap Tools software (CAÑAS et al., 2004 to meet the educational needs of a localized teaching situation. Data indicate that concept mapping, facilitated by computer software, can be a useful strategy to improve comprehension. Support for the investigation comes from the theories underlying the ESP approach, meaningful learning, learning as a social enterprise, and collaborative learning.Este artigo enfoca os procedimentos de uma pesquisa-ação (STRINGER, 2007 implementada em uma turma de alunos de graduação de um curso de inglês instrumental na Faculdade de Letras (UFMG. O impulso motivador foi a tentativa de criação de um meio para resolver um problema educativo localizado: o aumento do nível de compreensão de textos em inglês para fins acadêmicos. O processo de busca de uma possível solução envolveu o uso de mapas conceituais (NOVAK; CAÑAS, 2008, mediados pelo programa de computador CMap Tools (CAÑAS et al., 2004. Os dados indicam que a criação de mapas conceituais, empoderada pelo uso do CMap Tools, pode ser uma estratégia útil para aumentar o nível de compreensão escrita dos alunos. A investigação teve como suporte teórico os princípios da abordagem de inglês para fins específicos, aprendizagem significativa, aprendizagem como um ato social e aprendizagem colaborativa.

  5. [Toxicity of puffer fish fins].

    Science.gov (United States)

    Honda, Shunichi; Ichimaru, Shunichi; Arakawa, Osamu; Takatani, Tomohiro; Noguchi, Tamao; Ishizaki, Shoichiro; Nagashima, Yuji

    2007-10-01

    Puffer fish is prized as a Japanese traditional food and its fin is also used in the cuisine. However, whether the fin is edible or not is determined for convenience from the toxicity of skin, since little information is available about the toxicity of puffer fish fins. In the present study, we examined the toxicity of fins and skin of three toxic species, Takifugu vermicularis, T. snyderi, and T. porphyreus. The toxicity of T. vermicularis fins (< 5-52.4 MU/g) was significantly lower than that of skin (<5-1200 MU/g). HPLC analysis showed that tetrodotoxin was a major toxic principle irrespective of the toxicity value in each tissue of T. vermicularis. In the case of T. snyderi and T. porphyreus, the toxicity of fins was at almost the same level as that of the skin. The toxicity (< 10-12 MU/g) of caudal fins of T. porphyreus was apparently increased to 16.5-22.0 MU/g by drying. However, the toxin amounts in the dried fins were slightly decreased as compared with those of the non-dried fins. These results demonstrate that puffer fish with toxic skin also have toxic fins.

  6. Fin de Copenhagen

    DEFF Research Database (Denmark)

    Baumeister, Ruth

    2016-01-01

    FIN DE COPENHAGUE this book by the Danish Cobra artist Asger Jorn and the French philosopher Guy Debord, is the first in a series of two and was published in 1957, shortly before the authors founded the Situationist International. According to Jorn, upon arrival to Copenhagen, they stole some new......´s and Jorn´s theories but in its representation of the environment as a range of geographic, social, political and economic dynamics but also proposes a vision of the future city as a multi-layered network in a state of constant transformation....

  7. Desenvolvimento e validação de meio de cultura para detecção de Pseudomonas Aeruginosa em água purificada para fins farmacêuticos

    OpenAIRE

    Albini, Bárbara Pereira

    2012-01-01

    Resumo: A água purificada é uma das principais matérias-primas para medicamentos e cosméticos. Participa efetivamente de processos de esterilização por via úmida, limpeza de equipamentos e é utilizada nas análises de controle de qualidade. Assim, influencia diretamente na qualidade dos produtos e portanto deve seguir um rigoroso parâmetro de qualidade físico-químico e microbiológico. A Farmacopéia Brasileira 5 ed. que passa a vigorar em fevereiro do presente ano, indica como parâmetro microbi...

  8. Desenvolvimento e validação de meio de cultura para detecção de Pseudomonas Aeruginosa em água purificada para fins farmacêuticos

    OpenAIRE

    Albini,Bárbara Pereira

    2012-01-01

    Resumo: A água purificada é uma das principais matérias-primas para medicamentos e cosméticos. Participa efetivamente de processos de esterilização por via úmida, limpeza de equipamentos e é utilizada nas análises de controle de qualidade. Assim, influencia diretamente na qualidade dos produtos e portanto deve seguir um rigoroso parâmetro de qualidade físico-químico e microbiológico. A Farmacopéia Brasileira 5 ed. que passa a vigorar em fevereiro do presente ano, indica como parâmetro microbi...

  9. Brush/Fin Thermal Interfaces

    Science.gov (United States)

    Knowles, Timothy R.; Seaman, Christopher L.; Ellman, Brett M.

    2004-01-01

    Brush/fin thermal interfaces are being developed to increase heat-transfer efficiency and thereby enhance the thermal management of orbital replaceable units (ORUs) of electronic and other equipment aboard the International Space Station. Brush/fin thermal interfaces could also be used to increase heat-transfer efficiency in terrestrial electronic and power systems. In a typical application according to conventional practice, a replaceable heat-generating unit includes a mounting surface with black-anodized metal fins that mesh with the matching fins of a heat sink or radiator on which the unit is mounted. The fins do not contact each other, but transfer heat via radiation exchange. A brush/fin interface also includes intermeshing fins, the difference being that the gaps between the fins are filled with brushes made of carbon or other fibers. The fibers span the gap between intermeshed fins, allowing heat transfer by conduction through the fibers. The fibers are attached to the metal surfaces as velvet-like coats in the manner of the carbon fiber brush heat exchangers described in the preceding article. The fiber brushes provide both mechanical compliance and thermal contact, thereby ensuring low contact thermal resistance. A certain amount of force is required to intermesh the fins due to sliding friction of the brush s fiber tips against the fins. This force increases linearly with penetration distance, reaching 1 psi (6.9 kPa) for full 2-in. (5.1 cm) penetration for the conventional radiant fin interface. Removal forces can be greater due to fiber buckling upon reversing the sliding direction. This buckling force can be greatly reduced by biasing the fibers at an angle perpendicularly to the sliding direction. Means of containing potentially harmful carbon fiber debris, which is electrically conductive, have been developed. Small prototype brush/fin thermal interfaces have been tested and found to exhibit temperature drops about onesixth of that of conventional

  10. Blower Cooling of Finned Cylinders

    Science.gov (United States)

    Schey, Oscar W; Ellerbrock, Herman H , Jr

    1937-01-01

    Several electrically heated finned steel cylinders enclosed in jackets were cooled by air from a blower. The effect of the air conditions and fin dimensions on the average surface heat-transfer coefficient q and the power required to force the air around the cylinders were determined. Tests were conducted at air velocities between the fins from 10 to 130 miles per hour and at specific weights of the air varying from 0.046 to 0.074 pound per cubic foot. The fin dimensions of the cylinders covered a range in pitches from 0.057 to 0.25 inch average fin thicknesses from 0.035 to 0.04 inch, and fin widths from 0.67 to 1.22 inches.

  11. Caracterização molecular e variabilidade genética de acessos elite de mandioca para fins industriais Molecular characterization and genetic variability of elite cassava accessions for industrial purpose

    Directory of Open Access Journals (Sweden)

    Eduardo Alano Vieira

    2010-12-01

    Full Text Available Marcadores moleculares são ferramentas úteis na caracterização molecular de acessos de mandioca, em razão de apresentarem elevada capacidade de detecção das informações contidas no genoma. O objetivo deste trabalho foi caracterizar, por meio de marcadores RAPD, 20 acessos de mandioca para fins industriais conservados no Banco Regional de Germoplasma de Mandioca do Cerrado (BGMC. Em laboratório, os acessos foram avaliados por meio de marcadores RAPD, sendo posteriormente estimada a matriz de similaridade genética entre os acessos, por meio do índice de Jaccard. A análise, feita através de 11 iniciadores, gerou um total de 120 marcadores RAPD, dos quais 74 (62% foram polimórficos, revelando a presença de elevada variabilidade genética no grupo de acessos avaliados. A análise de agrupamento revelou a formação de apenas um agrupamento forte, formado pelos acessos BGMC 1130, BGMC 788, BGMC 1270 e BGMC 1107, o que indica que, no melhoramento genético de mandioca, não devem ser priorizadas hibridações entre esses acessos, sob pena de efeitos de endogamia. Por sua vez, o acesso BGMC 436 foi o mais divergente em relação aos demais e, como expressa elevado potencial produtivo na região do Cerrado do Brasil Central, representa boa opção como genitor para o melhoramento de mandioca para essa região. O estudo comprovou que os marcadores RAPD são eficientes na determinação da variabilidade genética dos acessos avaliados e que neste grupo existe elevada variabilidade genética passível de ser utilizada no melhoramento genético.Molecular markers are useful tools for the molecular characterization of cassava accessions since they present high capacity to detect information within the genome. The aim of this research was to characterize through RAPD molecular markers, 20 industrial cassava accessions conserved in the Cerrado Cassava Regional Germoplasm Bank ("Banco Regional de Germoplasma de Mandioca do Cerrado"-BGMC. Upon

  12. Desenvolvimento vegetativo e custo de produção de porta-enxertos de citros em recipientes para fins de subenxertia Vegetative development and production cost of citrus rootstocks in containers for inarching

    Directory of Open Access Journals (Sweden)

    Eduardo Augusto Girardi

    2007-05-01

    Full Text Available O objetivo deste trabalho foi avaliar o desenvolvimento vegetativo e estimar o custo de produção de 11 porta-enxertos de citros para fins de subenxertia, em diferentes recipientes. Avaliaram-se limão 'Cravo' clone Limeira (Citrus limonia Osbeck; citrumelo 'Swingle' (Poncirus trifoliata (L. Raf. x Citrus paradisi Macf.; tangerina 'Cleópatra' (Citrus reshni Hort. ex Tanaka; tangerina 'Sunki' (Citrus sunki Hort. ex Tanaka; limão 'Volkameriano' clone Catânia 2 (Citrus volkameriana Pasquale; laranja 'Caipira' clone DAC (Citrus sinensis L. Osbeck; limão 'Rugoso da África' clone Mazoe (Citrus jambhiri Lush.; Poncirus trifoliata 'Davis A'; tangerina 'Sun Shu Sha Kat' (Citrus sunki Hort. ex Tanaka; tangerina 'Sunki' clone 2506 ou Fruto Grande (Citrus sunki Hort. ex Tanaka e Poncirus trifoliata 'Barnes'. Foram utilizados tubetes de 290 mL, sacolas de 1,7 L, e porta-enxertos transplantados de tubetes de 75 mL para sacolas de polietileno de 1,7 e 4,5 L. Porta-enxertos produzidos diretamente em sacolas de 1,7 L atingem ponto ideal de subenxertia em menor tempo, de 100 a 150 dias após a semeadura, e permitem a obtenção de plantas maiores e com sistema radicular adequado, porém com custo de produção superior ao sistema de produção em tubetes de 290 mL.The vegetative development and the estimation of the production cost of eleven citrus rootstocks for inarching were evaluated in different containers. 'Rangpur' lime cultivar Limeira (Citrus limonia Osbeck; 'Swingle' citrumelo (Poncirus trifoliata (L. Raf. x Citrus paradisi Macf.; 'Cleópatra' mandarin (Citrus reshni Hort. ex Tanaka; 'Sunki' mandarin (Citrus sunki Hort. ex Tanaka; 'Volkamer' lemon cultivar Catânia 2 (Citrus volkameriana Pasquale; 'Caipira' sweet orange cultivar DAC (Citrus sinensis L. Osbeck; 'Rugoso da África' rough lemon cultivar Mazoe (Citrus jambhiri Lush.; Poncirus trifoliata cultivar Davis A; 'Sun Shu Sha Kat' mandarin (Citrus sunki Hort. ex Tanaka; 'Sunki' mandarin

  13. Toward quantum FinFET

    CERN Document Server

    Wang, Zhiming

    2013-01-01

    This book reviews a range of quantum phenomena in novel nanoscale transistors called FinFETs, including quantized conductance of 1D transport, single electron effect, tunneling transport, etc. The goal is to create a fundamental bridge between quantum FinFET and nanotechnology to stimulate readers' interest in developing new types of semiconductor technology. Although the rapid development of micro-nano fabrication is driving the MOSFET downscaling trend that is evolving from planar channel to nonplanar FinFET, silicon-based CMOS technology is expected to face fundamental limits in the near future. Therefore, new types of nanoscale devices are being investigated aggressively to take advantage of the quantum effect in carrier transport. The quantum confinement effect of FinFET at room temperatures was reported following the breakthrough to sub-10nm scale technology in silicon nanowires. With chapters written by leading scientists throughout the world, Toward Quantum FinFET provides a comprehensive introductio...

  14. L’hôtel particulier et la collection d’antiques de Florimond de Raemond (1540 ?-1601 : un exemple du paraître bordelais à la fin du XVIe siècle

    Directory of Open Access Journals (Sweden)

    Aurélie Plaut

    2009-11-01

    Full Text Available Florimond de Raemond bâtit peu à peu, quand il s’installa à Bordeaux en 1570 pour y exercer sa charge de conseiller au Parlement, une des maisons d’humanistes les plus visitées de la ville. Pendant près de trente ans, il collectionna statues et inscriptions antiques qu’il fit porter, au gré de ses découvertes, dans son jardin. Sa demeure témoignait ainsi du passé antique de Bordeaux si cher à l’intelligentsia locale du XVIe siècle. Si cette collection représenta pour lui un moyen d’offrir au grand public érudit la preuve de son raffinement et de sa culture, elle reflétait avant tout l’orgueil d’un homme désireux d’affirmer son appartenance à une noblesse provinciale. Elle lui permit de tisser des liens avec le cercle intellectuel bordelais et de devenir un membre très important de cette dernière. À une échelle plus grande, elle constitue un exemple intéressant des moyens mis en œuvre à cette époque pour construire une image de soi correspondant aux goûts du lieu où évoluaient ces hommes. Ainsi, l’étude de cette collection bordelaise nous permettra-t-elle de mieux appréhender les codes intellectuels, artistiques et sociaux de la noblesse érudite bordelaise à la fin du XVIe siècle.Paraître, autopromotion, « ethos préalable », « moi » social, Renaissance, Bordeaux.Florimond de Raemond gradually built one of the most visited humanist houses in Bordeaux after he settled there in 1570 to become a parliamentary counsellor. Over a period of about thirty years, he collected antique statues and inscriptions, which were installed in his garden as he found them. Thus his home was more of a lapidary museum, and displayed the antique past of Bordeaux, which was so dear to the local 16th century intelligentsia. Assuming that the museum represented for him a way of offering proof of refinement and culture to the learned public, it above all revealed the pride of a man anxious to assert his belonging

  15. En Defensa del Fin de Lucro en Salud.

    Directory of Open Access Journals (Sweden)

    Ramón Abel Castaño Yepes

    2007-06-01

    La tercera premisa, que es más bien tácita, es que el fin de lucro es legítimo para el médico pero no lo es para ningún otro actor que participa en la prestación de servicios de salud. De hecho, nuestra Ley 23 de 1981 plantea explícitamente que el trabajo

  16. Sobre limites e fronteiras: a reprodutibilidade do estoque territorial para os fins da acumulação capitalista Limites et frontières : la reproductibilité de la réserve territoriale aux fins d’accumulation capitaliste

    Directory of Open Access Journals (Sweden)

    César Ricardo Simoni Santos

    2011-07-01

    Full Text Available As palavras fronteira e limite, não raro, são empregadas como sinônimos, apesar da redução implicada nesse gesto. Mas não é difícil reconhecer que a primeira aparece mais frequentemente associada aos fenômenos espaciais enquanto a segunda parece estar mais próxima da indicação de fim ou esgotamento de qualquer natureza. É possível pensar numa relação entre elas, entretanto. No plano econômico, os limites da reprodução capitalista andam a par com a situação das fronteiras desse mesmo modo de produção. A dinâmica espacial do capitalismo é moldada de forma a, continuamente, ampliar seus próprios limites, internos e externos. A falta de possibilidades para a realização de novas inversões lucrativas vem em companhia da saturação dos espaços de investimentos. Nessas condições, atingido o limite provisório da reprodução naquele momento, novas fronteiras devem ser abertas. Na escassez de reservas territoriais não saturadas, normalmente de caráter não-capitalista, sobre as quais se pode avançar, os novos investimentos terão de disputar espaço entre seus pares. Nesse último caso, trata-se da abertura de fronteiras internas, meio pelo qual o avanço capitalista se opera num espaço já elaborado e ocupado pelos elementos e processos próprios da reprodução do capital. A expansão capitalista, desse modo, deverá se alimentar de um estoque de ativos desvalorizados deixados como resultado de alguma crise ou destruição de capital imposta por algum mecanismo que parte do interesse da fração restante em encontrar novos meios de valorização. Assim, temos claro que a reprodução do capital não exige necessariamente os territórios não-capitalistas ou os “mercados externos”, tal como pode imaginar Rosa Luxemburgo. Impondo a falência e processos de desvalorização para uma parte do capital em atividade, alguns capitalistas conseguem recriar as condições de investimentos no interior do mesmo espaço que

  17. 50 CFR 600.1204 - Shark finning; possession at sea and landing of shark fins.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Shark finning; possession at sea and landing of shark fins. 600.1204 Section 600.1204 Wildlife and Fisheries FISHERY CONSERVATION AND... PROVISIONS Shark Finning § 600.1204 Shark finning; possession at sea and landing of shark fins. (a)(1)...

  18. A multidisciplinary approach to identify pelagic shark fins by molecular, morphometric and digital correlation data Enfoque multidisciplinario para la identificación de aletas de tiburones pelágicos con datos moleculares, morfométricos y análisis digitales

    Directory of Open Access Journals (Sweden)

    Sebastián Hernández

    2010-04-01

    Full Text Available Accurate species identification is one of the most important issues to conserve and manage shark fisheries. A multidisciplinary approach involving molecular (using variation at ITS2 sequences, morphometrical and image processing species identification was performed to evaluate their discriminating power with three pelagic shark species common to the coasts of Chile (Prionace glauca Linnaeus 1785, Isurus oxyrinchus Rafinesque 1810, and Lamna nasus (Bonnaterre, 1788. Species-specific DNA markers and multivariate analyses based on twenty morphometrical measurements were used to identify fresh and dry fin sets for each shark species. Additionally, coloring patterns and fin shape were jointly used to distinguish dry fin sets of shark species by using digital invariant correlation (relation target and problem image independent of their changes in position, scale and rotation. Our results showed that morphometrical analysis was the least accurate approach, whereas DNA-based identification and image processing approaches were 100% successful on the identification of shark species. Thus ITS2 sequences and morphological diagnostic characteristics such as the ones related to color patterns, allow the correct identification of shark species. Therefore, the implementation of molecular and/or image tools can be applied to confidently identify the main pelagic shark species involved in Chilean landing and fin trade.La identificación correcta de las especies es uno de los más importantes temas para la conservación y el manejo de las pesquerías de tiburones. Un análisis multidisciplinario que involucra el procesamiento de datos moleculares, morfométricos e imágenes fue realizado para evaluar su capacidad de discriminación de tres especies de tiburones pelágicos comunes en las costas de Chile (Prionace glauca Linnaeus 1758, Isurus oxyrinchus Rafinesque 1810, and Lamna nasus Bonnaterre, 1788. Marcadores moleculares especie-específicos y an

  19. PHASE CHANGE AROUND A FINNED TUBE

    Directory of Open Access Journals (Sweden)

    Aytunç EREK

    2003-01-01

    Full Text Available This study presents the heat transfer enhancement in the thermal energy storage system by using radially finned tube. The solution of the system consists of the solving the equations of the heat transfer fluid (HTF, the pipe wall and fin, and the phase change material (PCM as one domain. The control volume finite difference approach and the semi implicit solver (SIS are used to solve the equations. Fully developed velocity distribution is taken in the HTF. Flow parameters (Re number and inlet temperature of coolant and fin parameters (the number of fins, fin length, fin thickness are found to influence solidification fronts and the total stored energy.

  20. Fin-tube solar collectors

    Science.gov (United States)

    1980-01-01

    Report presents test procedures and results of thermal-performance evaluation of seven commercial fin tube (liquid) solar collector-absorber plates. Tests were conducted indoors at Marshall Space Flight Center Solar simulator. Results are graphically shown along with supporting test data and summary, indicating efficiency as function of collector inlet temperature.

  1. Composição química de genótipos de cana-de-açúcar em duas idades, para fins de nutrição animal Chemical composition of sugarcane in two ages, for animal nutrition

    Directory of Open Access Journals (Sweden)

    João Batista de Andrade

    2004-12-01

    Full Text Available Foi desenvolvido, em 1999/2000, no Instituto de Zootecnia, em Nova Odessa (SP, um experimento para avaliar 60 genótipos de cana-de-açúcar (24 cultivares e 36 clones, para fins de alimentação animal. O experimento foi executado em delineamento de blocos ao acaso, com três repetições. Os genótipos foram amostrados aos 12 e 18 meses de idade. Para todas as características analisadas: porcentagem de matéria seca (%MS; de proteína bruta (%PB; de extrato etéreo (%EE; de matéria mineral (%MM; de carboidratos totais não estruturais (%CTN; de fibra insolúvel em detergente neutro (%FDN; de fibra insolúvel em detergente ácido (%FDA; de celulose (%CEL; de hemicelulose (%HEM; de lignina (%LIG, verificaram-se diferenças entre os genótipos e as idades de corte, com exceção para %EE, que não mostrou diferença entre as idades de corte. Para (%CTN, %NDF, %ADF, %CEL, %HEM e %LIG foram observadas diferenças dos genótipos nas idades de corte.At the Instituto de Zootecnia, Nova Odessa (SP, Brazil, it was carried out an experiment to evaluate 24 cultivars and 36 sugarcane clones as raw material for animal feeding. The experimental design was set in randomized blocks with three replications. The sugarcanes were harvested at 12 and 18 months. Genotypes and age of harvest showed differences for %DM (dry matter; %CP (crude protein; %EE (ether extract; %ACH (ach; %TNC (total non-structural carbohydrates , %NDF (neutral detergent fiber; %ADF (acid detergent fiber; %CEL (cellulose; %HCEL (hemicellulose and %LIG (lignin, except for %EE, for harvest ages. Significant differences for %TNC, %NDF, %ADF, %CEL, %HCEL and %LIG were observed for two ages of harvest.

  2. Course design, action research and the use of computers: challanges in an ESP course Desenho de curso, pesquisa-ação e o uso do computador: desafios num curso de línguas para fins específicos

    Directory of Open Access Journals (Sweden)

    Silvia Matravolgyi Damião

    2011-01-01

    Full Text Available This paper presents the results of an action research project that focused on the design and teaching of an ESP course and on the collaborative construction and development of a website. In the first year of the study, the course plan was modified due to the feedback given by the students and the same happened to the site, which was uploaded and modified according to the students' productions within the period. The course plan was reformulated in the second year of the study based on the experience acquired in the first year, and tasks were introduced to fulfill the students' academic and future professional needs. At the end of the second year of the study, it was possible to confirm that the course plan, with the modifications that were introduced, was adequate, and that the site reflected the tasks prepared by the students within the period, therefore reaching the objectives proposed at the beginning of the study. It was also possible to propose new directions for ESP teaching at the Institution where the research was carried out.Este artigo descreve os resultados de uma pesquisa-ação que teve como objetivos desenvolver e acompanhar um curso de linglês para fins específicose sua docência, bem como a construção e desenvolvimento de um website. No primeiro ano do trabalho, o plano de curso foi modificado, devido ao retorno dado pelos alunos e o mesmo aconteceu com o site, que foi sendo alimentado e modificado de acordo com as produções dos alunos no período. O plano de curso foi reformulado no segundo ano do estudo, com base na experiência adquirida no ano anterior, e tarefas foram introduzidas para ir ao encontro das necessidades acadêmicas e futuras necessidades profissionais dos alunos. Ao final do segundo ano da pesquisa, foi possível confirmar que o plano de curso, com as modificações implementadas, era adequado e que o site refletia as tarefas feitas pelos alunos durante o curso, confirmando-se, assim, os objetivos

  3. The optimum fin spacing of circular tube bank fin heat exchanger with vortex generators

    Science.gov (United States)

    Hu, Wanling; Su, Mei; Wang, Liangcheng; Zhang, Qiang; Chang, Limin; Liu, Song; Wang, Liangbi

    2013-09-01

    In real application, once the pattern of fin is determined, fin spacing of tube bank fin heat exchanger can be adjusted in a small region, and air flow velocity in the front of the heat exchanger is not all the same. Therefore, the effects of fin spacing on heat transfer performance of such heat exchanger are needed. This paper numerically studied the optimal fin spacing regarding the different front flow velocities of a circular tube bank fin heat exchanger with vortex generators. To screen the optimal fin spacing, an appropriate evaluation criterion JF was used. The results show that when front velocity is 1.75 m/s, the optimal fin spacing is 2.25 mm, when front velocity is 2.5 m/s, the optimal fin spacing is 2 mm, and when front velocity is higher than 2.5 m/s, the optimal fin spacing is 1.75 mm.

  4. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    Directory of Open Access Journals (Sweden)

    S.R.Mcilwain

    2010-02-01

    Full Text Available With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  5. A COMPARISON OF HEAT TRANSFER AROUND A SINGLE SERRATED FINNED TUBE AND A PLAIN FINNED TUBE

    OpenAIRE

    2010-01-01

    With comparable bundle geometry, serrated fin finned tube heat exchangers transfer more heat than plain finned ones. There are believed to be many factors in this behaviour, and this investigation used CFD to examine the heat transfer and fluid flow patterns around the fins to try to understand the magnitude of the differences in the processes. The study is a first step in developing a new theory-based method to predict the performance of serrated fin tube bundles.

  6. Determinantes sociales frente a estilos de vida en la diabetes mellitus de tipo 2 en Andalucía: ¿la dificultad para llegar a fin de mes o la obesidad? Social determinants vs. lifestyle in type 2 diabetes mellitus in Andalusia (Spain: difficulty in making ends meet or obesity?

    Directory of Open Access Journals (Sweden)

    Antonio Escolar Pujolar

    2009-10-01

    Full Text Available Objetivo: Valorar las relaciones de la dificultad para llegar a fin de mes con la obesidad y la diabetes mellitus de tipo 2 en Andalucía. Métodos: Estudio transversal basado en los datos de la Encuesta de Salud de Andalucía-2003. Cálculo de prevalencias y odds ratio (OR de tener diabetes mellitus de tipo 2 según variables de estilo de vida, y de obesidad y diabetes mellitus de tipo 2 según la dificultad autopercibida para llegar a fin de mes. Resultados: La OR ajustada por edad de tener diabetes mellitus de tipo 2 en personas obesas respecto a las de peso normal fue de 2,52 (intervalo de confianza del 95% [IC95%]:1,63-3,88 y de 2,13 (IC95%:1,28-3,54 en las mujeres y los hombres, respectivamente. El sedentarismo no se asoció con un riesgo significativo de diabetes mellitus de tipo 2 en ninguno de los dos sexos. Para las mujeres con mayor dificultad económica para llegar a fin de mes, respecto a las que tienen más facilidades, la OR de ser obesa, ajustada por edad y ejercicio físico, fue de 3,03 (IC95%:1,96-4,66, y la de diabetes mellitus de tipo 2, ajustada por edad, ejercicio físico e índice de masa corporal, fue de 2,55 (IC95%:1,28-5,10. En los hombres ninguna de las OR fue estadísticamente significativa. Conclusión: En las mujeres, las dificultades para llegar a fin de mes reflejan un contexto socioeconómico favorecedor de obesidad y de diabetes mellitus de tipo 2. Las desigualdades de clase social y género identificadas pueden contribuir a ampliar el actual marco explicativo de los determinantes de la diabetes mellitus de tipo 2, excesivamente centrado en las conductas individuales. La dificultad autopercibida para llegar a fin de mes podría utilizarse como indicador de pobreza en los estudios de desigualdades en salud.Objective: To assess the relationship between difficulty in making ends meet and obesity and type 2 diabetes mellitus in Andalusia. Methods: We performed a cross-sectional survey based on the Andalusian Health

  7. Effects of Fin Shape on Condensation Heat Transfer and Pressure Drop inside Herringbone Micro Fin Tubes

    Science.gov (United States)

    Miyara, Akio; Otsubo, Yusuke; Ohtsuka, Satoshi

    Experiments of in-tube condensation of R410A have been carried out for as mooth tube, a h elical micro fin tube and five types of herringbone micro fin tubes. In the herringbone micro fin tube, the micro fins work to remove liquid at fin-diverging parts and collect liquid at fin-converging parts. In the high mass velocity region, heat transfer coefficient of all the herringbone tubes is about 2-4 times higher than that of the helical micro fin tube. In the low mass velocity region, however, the heat transfer coefficients of the herringbone micro fin tubes are equal to or smaller than those of the helical micro fin tube. Up to the fin height of 0.18 mm, the heat transfer coefficient is higher for higher fin, whereas that of ah igher fin tube is saturated. The pressure drop increases with increasing fin height. The helix angle strongly affects the heat transfer and pressure drop. Higher helix angle causes higher heat transfer coefficient and higher pressure drop. In the case of the herringbone tube which has shorter fin and/or smaller helix angle, pressure drops are equal to or lower than that of the helical micro fin tube, whereas those of other tubes are higher.

  8. Avaliação de Métodos de Estimativa da Evapotranspiração de Referência para Fins de Manejo da Irrigação

    Directory of Open Access Journals (Sweden)

    Célia Maria Paiva

    2016-01-01

    Full Text Available O conhecimento da evapotranspiração das culturas é muito importante para o manejo da irrigação. A equação FAO56 Penman-Monteith tem sido recomendada pela FAO (Food and Agriculture Organization of the United Nations como método padrão para a estimativa da evapotranspiração de referência (ETo . Entretanto, esse método requer variáveis meteorológicas que em geral não são medidas nas estações meteorológicas no Brasil. Por isso, o objetivo deste estudo foi avaliar cinco métodos empíricos e comparar seus desempenhos com o de Penman-Monteith para as condições climáticas da região de Piraí do Sul no Estado do Paraná. Para tanto, foram utilizados dados meteorológicos registrados por uma plataforma de coleta de dados durante o período de 04/07/2008 a 12/10/2008 em uma cultura de trigo. Os resultados indicam que a ETo pode ser estimada adequadamente pelos métodos da Radiação Solar, Jensen-Haise e Makkink. O pior desempenho foi apresentado pelo método de Hargreaves-Samani, seguido do método de Camargo.

  9. Yield and quality of elephant grass biomass produced in the cerrados region for bioenergy Produção e qualidade da biomassa de capim-elefante produzido em ambiente dos cerrados para fins energéticos

    Directory of Open Access Journals (Sweden)

    Rilner A. Flores

    2012-10-01

    Full Text Available The objective of this study was to evaluate the performance of two genotypes of elephant grass, fertilized with and without N, for biomass production for energy use under the edaphoclimatic conditions of the Cerrado. The genotypes Roxo and Paraíso, grown in a field experiment in a Latosol in the Cerrado region were evaluated for biomass yield, nitrogen accumulation, C:N and stem:leaf ratios, fibre, ash and P and K contents and calorific value. The accumulated dry biomass ranged from 30 to 42 Mg ha-1 and showed no response to nitrogen fertilization with the lowest biomass obtained by the genotype Paraíso and the highest by Roxo. The total N accumulation followed the same pattern as for dry matter, ranging from 347 to 539 kg N ha-1. C:N and stem:leaf ratio of the biomass produced did not vary with treatments. The fibre contents were higher in genotype Paraíso and the highest levels of ash in the genotype Roxo. The K content in the biomass was higher in genotype Roxo and P did not vary between genotypes. The calorific value averaged 18 MJ kg-1 of dry matter and did not vary with the levels of N in leaves and stems of the plant. Both genotypes, independent of N fertilization, produced over 30 Mg ha-1 of biomass under Cerrado conditions.O presente trabalho objetivou avaliar o desempenho de dois genótipos de capim‑elefante para produção de biomassa para uso energético, em condições edafoclimáticas do Cerrado, fertilizados, ou não, com N. Avaliaram-se os rendimentos de biomassa, o acúmulo de nitrogênio, as relações C/N e colmo/folha, os teores de fibra, as cinzas da biomassa, os teores de K e P da biomassa e poder calorífico dos genótipos Paraíso e Roxo, cultivados em Latossolo, na região de Cerrado. A biomassa seca acumulada variou de 30 a 42 Mg ha-1, não havendo resposta à fertilização nitrogenada, sendo os menores obtidos com o genótipo Paraíso, e os maiores, com o Roxo. A acumulação total de N seguiu o mesmo

  10. Numerical Analysis of Aerodynamic Characteristics of the Finned Surfaces with Cross-inclined Fins

    Directory of Open Access Journals (Sweden)

    Lagutin A. E.

    2016-12-01

    Full Text Available This paper presents results of numerical research and analyses air-side hydraulic performance of tube bundles with cross inclined fins. The numerical simulation of the fin-tube heat exchanger was performed using the Comsol Femlab software. The results of modeling show the influence of fin inclination angle and tube pitch on hydraulic characteristics of finned surfaces. A series of numerical tests were carried out for tube bundles with different inclination angles (γ =900, 850, 650, 60, the fin pitch u=4 mm. The results indicate that tube bundles with cross inclined fins can significantly enhance the average integral value of the air flow rate in channel between fins in comparison with conventional straight fins. Aerodynamic processes on both sides of modificated channel between inclined fins were analyzed. The verification procedures for received results of numerical modeling with experimental data were performed.

  11. A biorobotic model of the sunfish pectoral fin for investigations of fin sensorimotor control

    Energy Technology Data Exchange (ETDEWEB)

    Phelan, Chris; Tangorra, James [Department of Mechanical Engineering, Drexel University, Philadelphia, PA 19104 (United States); Lauder, George [Museum of Comparative Zoology, Harvard University, Cambridge, MA 02138 (United States); Hale, Melina, E-mail: tangorra@coe.drexel.ed [Department of Organismal Biology and Anatomy, University of Chicago, Chicago, IL 60637 (United States)

    2010-09-15

    A comprehensive understanding of the control of flexible fins is fundamental to engineering underwater vehicles that perform like fish, since it is the fins that produce forces which control the fish's motion. However, little is known about the fin's sensory system or about how fish use sensory information to modulate the fin and to control propulsive forces. As part of a research program that involves neuromechanical and behavioral studies of the sunfish pectoral fin, a biorobotic model of the pectoral fin and of the fin's sensorimotor system was developed and used to investigate relationships between sensory information, fin ray motions and propulsive forces. This robotic fin is able to generate the motions and forces of the biological fin during steady swimming and turn maneuvers, and is instrumented with a relatively small set of sensors that represent the biological lateral line and receptors hypothesized to exist intrinsic to the pectoral fin. Results support the idea that fin ray curvature, and the pressure in the flow along the wall that represents the fish body, capture time-varying characteristics of the magnitude and direction of the force created throughout a fin beat. However, none of the sensor modalities alone are sufficient to predict the propulsive force. Knowledge of the time-varying force vector with sufficient detail for the closed-loop control of fin ray motion will result from the integration of characteristics of many sensor modalities.

  12. Visiones de fin de siglo

    OpenAIRE

    Acchini, Leonardo Martínez; Alejo, Esteban Ticona; Angulo, Salvador; Berthin, Elizabeth Cécile; Bravo, Carmen Giona; Bravo, María Celia; Burke, Melvin; C., Javier Sanjinés; Campi,Daniel; Canqui, Roberto Choque; Capra, Ana María Seoane de; Contreras, Manuel E.; Coro, Víctor Hugo Quintanilla; Correa, Loreto; Guerrero, Alicia Castellanos

    2016-01-01

    La presente publicación concentra los trabajos presentados por investigadores nacionales y extranjeros en el "Il Encuentro Internacional de Historia. El siglo XX en Bolivia y América Latina. Visiones de fin de siglo", que se realizó en la ciudad de Cochabamba entre el 27 y el 31 de julio de 1998. El encuentro fue organizado por la "Coordinadora de Historia. Investigadores Asociados" y contó con el auspicio del Centro Cultural Portales con sede en esa ciudad, así como con el apoyo de las sigui...

  13. Los mecanismos de satisfacción extraprocesal o carencia sobrevenida del objeto, y la enervación del desahucio, para poner fin al proceso de forma anticipada

    Directory of Open Access Journals (Sweden)

    Susana San Cristóbal Reales

    2012-01-01

    Full Text Available La liberalización del sector ferroviario de mercancías está resultando un proceso lento y costoso no sólo en nuestro país sino en el conjunto de los países europeos. No obstante, en los últimos meses se han adoptado importantes decisiones estratégicas que redundarán en un impulso notable para la consecución de los objetivos que sobre esta política se marcaron hace tiempo desde el ámbito del Derecho Comunitario Europeo con la aprobación de las Directivas integrantes de los tres paquetes ferroviarios. Dicho objetivo consiste en elevar sustancialmente el volumen de las mercancías desplazadas por ferrocarril en el conjunto de los países miembros como medio de transporte más ecológico, eficiente y conveniente para descongestionar el transporte de mercancías por carretera sin que ello suponga la desaparición de éste sino su complementariedad mediante una ecuación de sinergias a través de la intermodalidad.

  14. Optimum design of cast iron finned radiator

    Institute of Scientific and Technical Information of China (English)

    赵立华; 张泓森; 董重成

    2003-01-01

    The height, thickness and spacing of fins have an impact on the thermal characteristics of a radiator.The calculation of heat output and metal thermal intensity for cast iron finned radiator are given by using heat transfer formula of vertical plate and parallel fins. Each factor having effect on the metal thermal intensity of a radiator is analyzed and the optimum structure parameters of a radiator are given in order to maximize metal thermal intensity.

  15. Zoneamento climático de Pinus tecunumanii para fins de plantio experimental no estado de São Paulo Climatic zoning of Pinus tecunumanii for experimental stands establishment in São Paulo State, Brazil

    Directory of Open Access Journals (Sweden)

    Luiz Eduardo Mantovani

    2012-12-01

    Full Text Available O Pinus tecunumanii apresenta boa adaptação edafoclimática no Brasil e vem sendo plantado experimentalmente nos biomas mata atlântica e cerrado. O objetivo deste trabalho foi identificar as estações experimentais climaticamente homogêneas do estado de São Paulo para nortear a implantação de plantios experimentais de Pinus tecunumanii e, futuramente, os plantios comerciais. Foram selecionadas 30 áreas experimentais, em diferentes regiões do Estado de São Paulo, sendo que os dados climáticos referentes a cada estação foram organizados em planilhas e submetidos à análise multivariada, cujos resultados foram avaliados a partir de dendrogramas. As exigências climáticas da espécie foram verificadas em literatura científica e nos resultados obtidos de plantios experimentais. Toda a área do Estado de São Paulo se mostrou apta para plantios experimentais com as espécies de baixa altitude, exceto a área correspondente à estação de Campos do Jordão, devido à frequente ocorrência de geadas. A espécie também pode ser plantada nas estações de Angatuba, Buri, Pirajú, Itapeva, Avaré, Itapetininga e Itararé , exceto em áreas de baixada, onde existe o acúmulo de ar frio. Nas áreas mais quentes, tais como o norte / noroeste do estado, poderão ser efetuados testes para florescimento precoce, o que pode ser bastante útil para otimizar o tempo necessário para o melhoramento da espécie.Pinus tecunumanii has good adaptation to edafoclimatic regions of Brazil and these pinus have been cultivated on Savanna and Atlantic Forest biomes. The objective of this study was to identify climate homogeneous experimental stations of the Forest Institute of São Paulo and indicate places where it is possible to establish progeny and clone tests for breeding and further commercial plantation of this specie. It was selected 30 experimental areas at São Paulo state and climatic data for each meteorological station nearest of these areas

  16. VORTEX INDUCED VIBRATIONS OF FINNED CYLINDERS

    Institute of Scientific and Technical Information of China (English)

    SHA Yong; WANG Yong-xue

    2008-01-01

    This article presents the results of a numerical simulation on the vortex induced vibration of various finned cylinders at low Reynolds number. The non-dimensional, incompressible Navier-Stokes equations and continuity equation were adopted to simulate the fluid around the cylinder. The cylinder (with or without fins) in fluid flow was approximated as a mass-spring system. The fluid-body interaction of the cylinder with fins and uniform flow was numerically simulated by applying the displacement and stress iterative computation on the fluid-body interfaces. Both vortex structures and response amplitudes of cylinders with various arrangements of fins were analyzed and discussed. The remarkable decrease of response amplitude for the additions of Triangle60 fins and Quadrangle45 fins was found to be comparable with that of bare cylinder. However, the additions of Triangle00 fins and Quadrangle00 fins enhance the response amplitude greatly. Despite the assumption of two-dimensional laminar flow, the present study can give a good insight into the phenomena of cylinders with various arrangements of fins.

  17. De la Teoría a la Práctica en Investigación: Proyecto fin de carrera para alumnos de enfermería From theory to practice in research: Final career proyect for nursing students

    Directory of Open Access Journals (Sweden)

    Paloma Echevarría Pérez

    2004-11-01

    Full Text Available Introducción: Es bien sabido que la investigación en enfermería comienza a dar sus pasos, aunque todavía de una manera tímida. Para avanzar en el cuerpo de conocimientos propio se hace imprescindible conocer las diferentes estrategias metodológicas y ponerlas en práctica. No es posible avanzar si no se empieza desde las Escuelas de enfermería. Objetivo: En nuestro trabajo expondremos la necesidad de que el alumno realice una investigación en alguno de los campos o áreas de la Enfermería y las Ciencias de la Salud, con un carácter eminentemente práctico. Metodología: La asignatura es obligatoria para todos los alumnos de tercer curso, siendo la única Escuela en España que así lo hace. Se organiza en seminarios teórico-prácticos y en sesiones de seguimiento personalizadas tras la adjudicación de un director de proyecto dentro del claustro de profesores. Conclusiones: En los cuatro años que llevamos de experiencia se han realizado trabajos de alta calidad y, lo que es más importante, el alumno le ha perdido el miedo a la investigación y tendrá la experiencia suficiente para continuar cuando se enfrente al mundo laboral.Introduction: it is a well-known fact that research in the field of nursing has already started though in a timid way. It is essential to know the different methodological strategies and put them into practice in order to make progress in the body of specific knowledge. This progress will not be possible, however, if the Schools of Nursing are not taken as the starting point. Objective: In our paper, we will show the need for the students to carry out a research in any of the fields or areas of Nursing and Health Sciences, this research being basically of a practical nature. Methods: the subject is compulsory for all students in their third year, being this the only School of Nursing in Spain that envisages a situation of this kind. The subject is organized in theoretical and practical seminars and in sessions

  18. El Trabajo Fin de Grado Maestro: modalidad online con evaluación presencial

    OpenAIRE

    Blanca Arteaga Martínez; Josu Ahedo Ruiz; Sonia Gutiérrez Gómez-Calcerrada; Eva Solera Hernández

    2013-01-01

    El plan Bolonia establece que todos los grados deben concluir con la realización de un Trabajo Fin Grado (TFG), cuyo objetivo principal es capacitar al alumno para su futura profesión. La legislación vigente en España permite cierta autonomía para que las Universidades desarrollen esta tarea. En el presente artículo se realiza un análisis de la situación sobre cómo las Universidades españolas ofertan el Grado de Maestro en Educación Infantil y Primaria e imparten el Trabajo Fin de Grado. Se s...

  19. Viabilidade do aproveitamento de resíduos de fibras vegetais para fins de obtenção de material de construção Suitability of vegetable fiber residues as construction material

    Directory of Open Access Journals (Sweden)

    Holmer Savastano Junior

    2000-04-01

    Full Text Available O presente estudo abordou a existência e as principais características de vinte resíduos de fibras vegetais, resultantes de processos agroindustriais, voltados para a obtenção de oito diferentes tipos de fibras comerciais. Com base em critérios de seleção inicialmente estabelecidos, foram identificados seis resíduos de maior interesse. Os resultados indicaram a potencialidade do seu emprego, no reforço de matrizes frágeis, à base de cimento Portland, para aumento de sua ductilidade. Telhas produzidas a partir de compósitos reforçados com fibras residuais de sisal "baler twine", coco, polpa de eucalipto, malva e banana, além de combinação entre fibras de coco e polpa de eucalipto, resistiram a cargas na flexão, superiores a 680 N, em conformidade com especificações internacionais.Twenty vegetable fiber by-products from agro-industrial production of eight different commercial fibers were analyzed in this study. Based on previously established selection criteria, six main types of residue were identified. Results showed that the selected by-products may be used as reinforcement of fragile cementitious matrices, for ductility improvement. Tiles produced with composites reinforced by residual fibers of sisal baler twine, coir, eucalyptus pulp, malva, banana, or a mixture of coir fibers and eucalyptus pulp, supported flexural loads in excess of 680N in keeping with international specifications.

  20. Performance study of a fin and tube heat exchanger with different fin geometry

    OpenAIRE

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross-sections namely: a) Rectangular, b) Trapezoidal, c) Triangular are adopted to define the fin geometry. The CFD simulations are performed to incorporate coupled steady state conjugate heat transfer with the...

  1. Modelagem do volume de reservatórios de irrigação para fins de outorga e planejamento agrícola Modeling of the irrigation reservoirs for concession and agricultural projection

    Directory of Open Access Journals (Sweden)

    Adroaldo Dias Robaina

    2009-12-01

    Full Text Available No Estado do Rio Grande do Sul, a utilização crescente de sistemas de irrigação vem tornando cada vez mais importante a reservação de água através de barragens. Neste caso, é essencial a determinação do volume de água disponível nessas estruturas para o adequado planejamento dos sistemas irrigados e outorga para o uso da água. Atualmente, a determinação do volume é pouco frequente porque o método direto (batimetria caracteriza-se por ser oneroso, além de exigir mão-de-obra especializada e tempo disponível. Diante do exposto, este trabalho teve por objetivo avaliar um modelo matemático para a determinação do volume de água armazenado em reservatórios de irrigação. O modelo matemático escolhido foi representado pela fórmula de Schoklisch, em que o volume de água de um reservatório é dado pelo produto da área e profundidade máxima em nível normal e o parâmetro de Schoklisch (η. Foi feita a análise do parâmetro η a partir dos dados fornecidos por 210 reservatórios com finalidade de irrigação, localizados na região da Campanha do Estado do Rio Grande do Sul. Através dos resultados, pode-se observar que o valor do coeficiente de Schoklisch (η variou entre 0,47 e 0,53, apresentando um valor médio de 0,50 e desvio padrão de 0,05, considerando-se os municípios em conjunto. Observou-se, ainda, que todos os locais estudados enquadraram-se na classe de desempenho ótimo. Os coeficientes de determinação encontrados para as regiões de estudo foram superiores a 0,99. A relação entre o volume estimado e o volume observado em reservatórios demonstra o alto grau de correlação entre os valores testados e permite a recomendação do uso do modelo de Schoklisch para a determinação do volume de água armazenado em reservatórios de irrigação nas localidades em estudo.In the Rio Grande do Sul state, the irrigation systems for growing use contributes to make the water reserves through barrages more important

  2. The use of hydraulic bolts for coupling in order to shorten the maintenance critical path in turbo generator sites; Uso de tornillos hidraulicos para acoplamiento a fin de acortar la ruta critica del mantenimiento en sitios de turbogeneradores

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Arelle, Carlos [Turbomaquinas S. A. de C.V., La Piedad, Michoacan (Mexico)

    2007-11-15

    The use of hydraulic bolts has permitted to diminish the time in the critical path of the maintenance, attaining to reduce the total costs and avoiding that some bolts are stuck, benefits the on time planning of the maintenance. The bolts of radial adjustment provide significant benefits to the General Turbine operator. The hydraulic bolts avoid the normal problems of the conventional coupling bolts and rapidly help to re-establish the couple concentricity. The bolts are individually designed to meet a specific geometry and are a direct replacement of the conventional bolts. [Spanish] El uso de tornillos hidraulicos ha permitido disminuir el tiempo de la ruta critica del mantenimiento, logrando reducir los costos totales y al evitar que algun tornillo se atore, beneficia la planeacion de mantenimientos a tiempo. Los tornillos de ajuste radial proveen beneficios significativos al operador de la Turbina General. Los tornillos hidraulicos eliminan los problemas normales de los tornillos de acoplamiento convencionales y rapidamente ayudan a restablecer la concentridad del cople. Los tornillos son disenados individualmente para completar una geometria especifica y son un reemplazo directo de los tornillos convencionales.

  3. Plastic Guidance Fins for Long Rod Projectiles .

    Directory of Open Access Journals (Sweden)

    Mark L. Bundy

    1997-10-01

    Full Text Available Projectile tail fins on long rod kinetic energy (KE penetrators serve the same purpose as fletchings (feathers on an arrow, namely, they help align the projectile axis with its velocity vector. This reduces the projectile's yaw and hence reduces its aerodynamic drag. In addition, a low yaw angle at target impact helps to maximise the projectile's target penetration. It is typical for projectiles to exit the gun muzzle and enter free flight at some ndn-zero yaw angle. Aerodynamic forces acting on yawed tail fins create a stabilising torque about the projectile's centre of gravity (CG. This torque can be increased by making the fin material lighter. Most conventional long rod penetrators fired from high performance guns have tail fins made from aluminium. However, aluminium can undergo catastrophic oxidation (rapid burning in-bore. Coating aluminium with Al/sub 2/O/sub 3/ {hardcoat prevents ignition of the substrate, provided solid propellant grain impacts do not chip the brittle hardcoat off the surface. Plastic is lighter than aluminium and less exothermic when oxidized. Therefore, other factors aside, it is conceivable that plastic fins could increase projectile stability while incurring less thermal erosion than aluminium. However, thermal loads are not the only concern when considering plastic as an alternative tail fin material. The mechanical strength of plastic is also a critical factor. This paper discusses some of the successes and failures of plastic fins, at least relatively thin fins, for use as KE stabilisers.

  4. Turbulent flow in longitudinally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Edwards, D.P.; Hirsa, A.; Jensen, M.K. [Rensselaer Polytechnic Inst., Troy, NY (United States). Dept. of Mechanical Engineering, Aeronautical Engineering and Mechanics

    1996-09-01

    An experimental investigation of fully developed, steady, turbulent flow in longitudinally finned tubes has been performed. A two-channel, four-beam, laser-Doppler velocimeter was used to measure velocity profiles and turbulent statistics of air flow seeded with titanium dioxide particles. Mean velocities in axial, radial, and circumferential directions were measured over the tube cross sections and pressure drop in the tubes was measured at six stations along the test section length in order to calculate the fully developed friction factor. Four experimental tube geometries were studied: one smooth tube; two 8-finned tubes (fin height-to-radius ratios of 0.333 and 0.167), and one 16-finned tube (fin height-to-radius ratio of 0.167); detailed measurements were taken at air flow rates corresponding to Reynolds numbers of approximately 5,000, 25,000, and 50,000. Friction factor data were compared to literature results and showed good agreement for both smooth and finned tubes. The wall shear stress distribution varied significantly with reynolds number, particularly for Reynolds numbers of 25,000 and below. Maximum wall shear stress was found at the fin tip and minimum at the fin root. Four secondary flow cells were detected per fin (one in each interfin spacing and one in each core region for each fin); secondary flows were found to be small in comparison to the mean axial flow and relative magnitudes were unaffected by axial flow rate at Reynolds numbers above 25,000. The fluctuating velocities had a structure similar to that of the smooth tube in the core region while the turbulence in the interfin region was greatly reduced. The principal, primary shear stress distribution differed considerably from that of the smooth tube, particularly in the interfin region, and the orientation was found to be approximately in the same direction as the gradient of the mean axial velocity, supporting the use of an eddy viscosity formulation in turbulence modeling.

  5. A comparison of two formulations of the fin efficiency for straight fins

    Science.gov (United States)

    Momoniat, Ebrahim

    2012-04-01

    A formulation of the fin efficiency based on Newton's law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base. The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known, whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known. This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined. The second formulation of the fin efficiency is exact when the first integrals can be determined.

  6. A comparison of two formulations of the fin efficiency for straight fins

    Institute of Scientific and Technical Information of China (English)

    Ebrahim Momoniat

    2012-01-01

    A formulation of the fin efficiency based on Newton's law of cooling is compared with a formulation based on a ratio of heat transferred from the fin surface to the surrounding fluid to the heat conducted through the base.The first formulation requires that the solution of the nonlinear fin equations for constant heat transfer coefficient and constant thermal conductivity is known,whilst the second formulation of the fin efficiency requires only that a first integral of the model equation is known.This paper shows the first formulation of the fin efficiency contains approximation errors as only power series and approximate solutions to the nonlinear fin equations have been determined.The second formulation of the fin efficiency is exact when the first integrals can be determined.

  7. Um método simplificado de fusão de imagens para fins de interpretação visual = A simplified merging method applied to image data for purposes of visual interpretation

    Directory of Open Access Journals (Sweden)

    Selma Regina Aranha Ribeiro

    2009-01-01

    Full Text Available A fusão de imagens é um tema que desperta interesse pela coleta de imagens multiespectrais e pancromáticas com diferentes resoluções espaciais e espectrais. O método de fusão ganhou grande reconhecimento quando imagens Landsat multiespectrais puderamser combinadas com imagens SPOT pancromáticas. Esse processo comprovou ser útil na geração de imagens híbridas que combinam as propriedades das imagens originais numa única nova imagem, que preserva a informação espectral e possui melhor informaçãoespacial. O resultado é uma nova imagem com maior resolução espacial e preservação da maior resolução espectral. Este documento apresenta o método I1I2I3, introduzido por Ohta et al. (1980, como uma opção de fusão por substituição em relação ao método RGBIHS. Para aplicar o método I1I2I3 e o RGB-IHS, duas imagens de altas resoluções foramutilizadas, Ikonos II e Quickbird.Image merging is a topic that has drawn new interest due to theacquirement of multispectral and panchromatic images with different resolutions. The merging approach received great recognition when multispectral Landsat images were matched with panchromatic SPOT images. This process proved to be useful for generating hybrid images that combine properties from the originals into a new unique image, still maintaining spectral information and featuring improved spatial information. The result is a new image with better spatial and preserved spectral resolution. This paper presents the I1I2I3 merging method, introduced by Ohta et al. (1980, as an option for image merging through substitution in relation to the RGB-HSI method. In order to apply the I1I2I3 and RGB-HIS methods, two high resolution images were utilized, Ikonos II and Quickbird.

  8. Fin shape thermal optimization using Bejan's constuctal theory

    CERN Document Server

    Lorenzini, Giulio

    2011-01-01

    The book contains research results obtained by applying Bejan's Constructal Theory to the study and therefore the optimization of fins, focusing on T-shaped and Y-shaped ones. Heat transfer from finned surfaces is an example of combined heat transfer natural or forced convection on the external parts of the fin, and conducting along the fin. Fin's heat exchange is rather complex, because of variation of both temperature along the fin and convective heat transfer coefficient. Furthermore possible presence of more fins invested by the same fluid flow has to be considered.Classical fin theory tri

  9. Methylmercury in dried shark fins and shark fin soup from American restaurants.

    Science.gov (United States)

    Nalluri, Deepthi; Baumann, Zofia; Abercrombie, Debra L; Chapman, Demian D; Hammerschmidt, Chad R; Fisher, Nicholas S

    2014-10-15

    Consumption of meat from large predatory sharks exposes human consumers to high levels of toxic monomethylmercury (MMHg). There also have been claims that shark fins, and hence the Asian delicacy shark fin soup, contain harmful levels of neurotoxic chemicals in combination with MMHg, although concentrations of MMHg in shark fins are unknown. We measured MMHg in dried, unprocessed fins (n=50) of 13 shark species that occur in the international trade of dried shark fins as well as 50 samples of shark fin soup prepared by restaurants from around the United States. Concentrations of MMHg in fins ranged from 9 to 1720 ng/g dry wt. MMHg in shark fin soup ranged from sharks such as hammerheads (Sphyrna spp.). Consumption of a 240 mL bowl of shark fin soup containing the average concentration of MMHg (4.6 ng/mL) would result in a dose of 1.1 μg MMHg, which is 16% of the U.S. EPA's reference dose (0.1 μg MMHg per 1 kg per day in adults) of 7.4 μg per day for a 74 kg person. If consumed, the soup containing the highest measured MMHg concentration would exceed the reference dose by 17%. While shark fin soup represents a potentially important source of MMHg to human consumers, other seafood products, particularly the flesh of apex marine predators, contain much higher MMHg concentrations and can result in substantially greater exposures of this contaminant for people.

  10. El proteccionismo de fin de siglo

    Directory of Open Access Journals (Sweden)

    Marcela SABATÉ SORT

    2010-02-01

    Full Text Available RESUMEN: Dentro del análisis de la política comercial de la Europa continental, este trabajo profundiza en la reacción proteccionista que, contrastando con la apertura anterior, caracteriza el final del siglo XIX y los primeros años del XX, justo hasta el comienzo de la Gran Guerra. Para ello indaga en los factores, especialmente las consecuencias de la "Gran Depresión", que provocan este cambio, en las políticas comerciales de los principales países europeos ante la crisis y en los niveles de protección establecidos. Unas reflexiones finales sobre el común movimiento de elevación arancelaria que preside la evolución de las políticas comerciales del continente en esta etapa y el diverso grado de protección decidido, permiten definir con exactitud la reacción proteccionista realmente acometida. Palabras Clave. Política comercial, Proteccionismo, Crisis económica, Estado, Fin de siglo. ABSTRACT: Within the analysis of the commercial policy of continental Europe, this study delves deeper into the protectionist reaction which, in contrast with the former openness, characterised the end of the nineteenth century and the beginning of the twentieth, right up until he beginning of the Great War. It inquires into the factors that provoked this change, especially the consequences of the Great Depression, and into the commercial policies of the main European countries in the face of this crisis, as well as the levels of protection established. Some final reflections on the common movement to raise tariffs which presided the evolution of the continent's commercial policies during this stage and the diverse degree of protection decided on make it possible to precisely define the protectionist action really undertaken. Key Words: Commercial Policy, Protectionism, Economic Crisis, State, Turn of the Century.

  11. Ice formation around isothermal radial finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, K.A.R.; Henriquez, J.R.; Moura, L.F.M.; Ganzarolli, M.M. [UNICAMP-FEM-DETF, Campinas (Brazil)

    2000-04-01

    The present study presents a thermal numerical model for the solidification of Phase Change Material around a radially finned tube with a constant wall temperature. The model is based upon a pure conduction formulation and the enthalpy method. The finite difference approach and the alternating direction implicit scheme are used to discretize the system of equations and the associated boundary, initial and final conditions. Numerical experiments were realized to optimise the numerical code. Numerical simulations were performed to investigate the effects, of the number of fins, fin thickness, fin material, aspect ratio of the tube arrangement and the tube wall temperature. Graphical results were presented, discussed and equations relating the effect of each of the variables on the time for complete solidification are also presented. (author)

  12. Genetic algorithm optimization for finned channel performance

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Compared to a smooth channel, a finned channel provides a higher heat transfer coefficient; increasing the fin height enhances the heat transfer. However, this heat transfer enhancement is associated with an increase in the pressure drop. This leads to an increased pumping power requirement so that one may seek an optimum design for such systems. The main goal of this paper is to define the exact location and size of fins in such a way that a minimal pressure drop coincides with an optimal heat transfer based on the genetic algorithm. Each fin arrangement is considered a solution to the problem(an individual for genetic algorithm). An initial population is generated randomly at the first step. Then the algorithm has been searched among these solutions and made new solutions iteratively by its functions to find an optimum design as reported in this article.

  13. alternativas para promoverla

    Directory of Open Access Journals (Sweden)

    Carlos Muñoz Izquierdo

    2006-01-01

    Finalmente, se analizan las políticas que han sido aplicadas con el fin de combatir ese problema, y se sugieren algunos cursos de acción que se consideran potencialmente más eficaces para lograr ese propósito.

  14. Música costarricense para cuerdas

    OpenAIRE

    Mora-Bermúdez, Eddie

    2010-01-01

    Dar a conocer, por medio de ediciones, la música costarricense para cuerdas, con el fin de enriquecer el medio musical costarricense. Universidad de Costa Rica UCR::Docencia::Artes y Letras::Facultad de Bellas Artes::Escuela de Artes Musicales

  15. Curvature Could Give Fish Fins Their Strength

    National Research Council Canada - National Science Library

    2017-01-01

    ... maneuverable is by having the ability to generate varying amounts of force on the water when flapping a fin,” said Shreyas Mandre, an assistant professor in Brown’s School of Engineering and a co-author of the research. “We think that fish modulate curvature at the base of the fin to make it stiffer or softer, which alters the force they gene...

  16. PHASE CHANGE AROUND A FINNED TUBE

    OpenAIRE

    EREK, Aytunç

    2003-01-01

    This study presents the heat transfer enhancement in the thermal energy storage system by using radially finned tube. The solution of the system consists of the solving the equations of the heat transfer fluid (HTF), the pipe wall and fin, and the phase change material (PCM) as one domain. The control volume finite difference approach and the semi implicit solver (SIS) are used to solve the equations. Fully developed velocity distribution is taken in the HTF. Flow parameters (Re number and in...

  17. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    OpenAIRE

    2014-01-01

    ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT ...

  18. Thermal transport in oblique finned microminichannels

    CERN Document Server

    Fan, Yan; Singh, Pawan Kumar; Lee, Yong Jiun

    2015-01-01

    The main aim of this book is to introduce and give an overview of a novel, easy, and highly effective heat transfer augmentation technique for single-phase micro/minichannel heat sink. The specific objectives of the volume are to: Introduce a novel planar oblique fin microchannel and cylindrical oblique fin minichannel heat sink design using passive heat transfer enhancement techniques  Investigate the thermal transport in both planar and cylindrical oblique fin structures through numerical simulation and systematic experimental studies. Evaluate the feasibility of employing the proposed solution in cooling non-uniform heat fluxes and hotspot suppression Conduct the similarity analysis and parametric study to obtain empirical correlations to evaluate the total heat transfer rate of the oblique fin heat sink Investigate the flow mechanism and optimize the dimensions of cylindrical oblique fin heat sink Investigate the influence of edge effect on flow and temperature uniformity in these oblique fin chan...

  19. The art of fin regeneration in zebrafish.

    Science.gov (United States)

    Pfefferli, Catherine; Jaźwińska, Anna

    2015-04-01

    The zebrafish fin provides a valuable model to study the epimorphic type of regeneration, whereby the amputated part of the appendage is nearly perfectly replaced. To accomplish fin regeneration, two reciprocally interacting domains need to be established at the injury site, namely a wound epithelium and a blastema. The wound epithelium provides a supporting niche for the blastema, which contains mesenchyme-derived progenitor cells for the regenerate. The fate of blastemal daughter cells depends on their relative position with respect to the fin margin. The apical compartment of the outgrowth maintains its undifferentiated character, whereas the proximal descendants of the blastema progressively switch from the proliferation program to the morphogenesis program. A delicate balance between self-renewal and differentiation has to be continuously adjusted during the course of regeneration. This review summarizes the current knowledge about the cellular and molecular mechanisms of blastema formation, and discusses several studies related to the regulation of growth and morphogenesis during fin regeneration. A wide range of canonical signaling pathways has been implicated during the establishment and maintenance of the blastema. Epigenetic mechanisms play a crucial role in the regulation of cellular plasticity during the transition between differentiation states. Ion fluxes, gap-junctional communication and protein phosphatase activity have been shown to coordinate proliferation and tissue patterning in the caudal fin. The identification of the downstream targets of the fin regeneration signals and the discovery of mechanisms integrating the variety of input pathways represent exciting future aims in this fascinating field of research.

  20. Studi Analitik dan Numerik Perpindahan Panas pada Fin Trapesium (Studi Kasus pada Finned Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Ahmad Zaini

    2013-09-01

    Full Text Available Penambahan fin pada pipa penukar kalor merupakan suatu upaya memperbesar perpindahan kalor konduksi dan konveksi, dengan cara memperluas bidang geometri. Pada penelitian ini dianalisa secara analitik dan numerik perpindahan kalor pada fin dengan profil longitudinal tidak seragam atau berubah terhadap jarak dari dasar fin, dengan memvariasikan ketebalan ujung fin. Hasil dari kedua studi ini tidak jauh berbeda, pada keduanya menjelaskan bahwa fin dengan ketebalan ujung 0,9 mm (fin trapesium terbalik paling baik dari 5 variasi lainnya; serta perubahan temperatur paling besar terjadi pada sepertiga pertama dari panjang  fin, ini artinya pelepasan kalor terbesar terjadi pada daerah tersebut. Perbedaannya adalah pada persentase penurunan temperatur sepanjang  fin terhadap temperatur dasar fin, untuk ketebalan 0,9 mm pada studi analitik sebesar 91,92% dan pada studi numerik sebesar 91,78%. Hal ini berarti metode penyelesaian persamaan diferensial orde 2 dengan koefisien variabel dengan cara pembedahan koefisien variabel pada ODE, sudah benar dan valid. Namun bila ditinjau dari waktu yang diperlukan untuk komputasinya, studi analitik membutuhkan waktu lebih lama. Waktu yang diperlukan dalam komputasinya tergantung dari fungsi koefisien variabel.

  1. Performance study of a fin and tube heat exchanger with different fin geometry

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross...... and pressure loss characteristics such as Nusselt number, Euler number, and efficiency index are determined and utilized to compare the performance of different fin geometries. The results obtained from the models are verified using experimentally developed correlations. The results obtained from the numerical...

  2. Avaliação de cultivares de soja, sob manejo orgânico, para fins de adubação verde e produção de grãos Evaluation of soybean cultivars under organic management for green manuring and grain production

    Directory of Open Access Journals (Sweden)

    Milton Parron Padovan

    2002-12-01

    Full Text Available O objetivo deste trabalho foi avaliar o desempenho de seis cultivares de soja, sob manejo orgânico, para fins de adubação verde e produção de grãos. Utilizou-se delineamento experimental de blocos casualizados, com quatro repetições por tratamento (cultivar. Na época da colheita, 81 dias após a emergência das plântulas, todas as cultivares testadas (Celeste, Surubi, Campo Grande, Mandi, Lambari e Taquari mostraram excelente nodulação, variando de 545 a 760 mg/planta de massa nodular seca. As cultivares Celeste e Taquari, que produziram, respectivamente, 8,33 e 7,12 t ha-1 de biomassa seca da parte aérea, apresentaram outras características agronômicas vantajosas, tais como: ciclo curto, alta acumulação de nutrientes (N, P, K, Ca e Mg nos tecidos verdes e bom rendimento de sementes. Esses caracteres indicam potencial de 'Celeste' e 'Taquari' para adubação verde de verão em sistemas de agricultura orgânica. Cinco das cultivares avaliadas revelaram tendência ao acamamento, porém dentro de níveis aceitáveis. As cultivares Celeste, Surubi, Campo Grande, Mandi e Taquari suplantaram em 23%, 32%, 33%, 44% e 70%, respectivamente, a média nacional de produtividade de soja, estimada em 2.398 kg ha-1 nas últimas três safras.The objective of this work was to evaluate the grain and aboveground biomass production of six soybean cultivars under organic management. A randomized block design was adopted with four replications per treatment (cultivar. By harvest time, 81 days after plants emergence, all tested cultivars (Celeste, Surubi, Campo Grande, Mandi, Lambari, and Taquari had excellent nodulation ranging from 545 to 760 mg/plant of nodule mass (dry weight. The cultivars Celeste and Taquari, which yielded 8.33 and 7.12 t ha-1 of dry biomass, respectively, showed other advantageous agronomic characteristics such as: short cycle, a high accumulation of nutrients (N, P, K, Ca and Mg in green tissues, and good seed setting. These

  3. 14 CFR 23.445 - Outboard fins or winglets.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Outboard fins or winglets. 23.445 Section... § 23.445 Outboard fins or winglets. (a) If outboard fins or winglets are included on the horizontal... with loads induced by the fins or winglets and moments or forces exerted on the horizontal surfaces...

  4. Some aspects of film condensation of steam on finned tubes

    OpenAIRE

    Coumes, James M.

    1989-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for filmwise condensation of steam on smooth tubes and finned tubes with rectangular-shaped fins. The influence of fin root diameter on a single horizontal finned tube was examined by taking data for two families of tubes whose fin root diameters were 12.7 and 19.05 mm. Each family of tubes had fins that were 1 mm thick and 1 mm high but with fin spacings of 0.25, 0.50, 1.0, 1.5, 2.0, and 4.0 mm. ...

  5. Flow and heat transfer in compact offset strip fin surfaces

    Institute of Scientific and Technical Information of China (English)

    Junqi DONG; Jiangping CHEN; Zhijiu CHEN

    2008-01-01

    Experimental studies of air-side heat transfer and pressure drop characteristics of offset strip fins and flat tube heat exchangers were performed. A series of tests were conducted for 9 heat exchangers with different fin space, fin height, fin strip length and flow length, at a constant tube-side water flow rate of 2.5 m3/h. The char-acteristics of the heat transfer and pressure drop of differ-ent fin space, fin height and fin length were analyzed and compared. The curves of the heat transfer coefficients vs. The pumping power per unit frontal area were then plot-ted. Moreover, the enhanced heat transfer mechanism of offset strip fins was analyzed using field synergy theory. The results showed that fin length and flow length have more obviously effect on the thermal hydraulic character-istics of offset strip fins.

  6. Ocio Inclusivo para personas con discapacidad

    OpenAIRE

    Ruiloba Arce, Marta María

    2014-01-01

    Mi proyecto de Fin de Grado trata del ocio inclusivo para personas con discapacidad intelectual. Como educadora social apuesto por la inclusión social para la mejora de calidad de vida de las personas, siendo uno de los medios más efectivos para lograr una sociedad sin diferencias ni prejuicios. [...

  7. Crystallization fouling of finned tubes during pool boiling: effect of fin density

    Energy Technology Data Exchange (ETDEWEB)

    Esawy, M.; Malayeri, M.R. [University of Stuttgart, Institute for Thermodynamics and Thermal Engineering (ITW), Stuttgart (Germany); Mueller-Steinhagen, H. [University of Stuttgart, Institute for Thermodynamics and Thermal Engineering (ITW), Stuttgart (Germany); German Aerospace Centre (DLR), Institute of Technical Thermodynamics, Stuttgart (Germany)

    2010-11-15

    Bubble characteristics such as density, size, frequency and motion are key factors that contribute to the superiority of nucleate pool boiling over other modes of heat transfer. Nevertheless, if heat transfer occurs in an environment prone to fouling, the very same parameters may lead to accelerated deposit formation due to concentration effects beneath the growing bubbles. This has led to the widely accepted design recommendation to maintain the heat transfer surface temperature below the boiling point if fouling may occur, e.g., in seawater desalination. The present paper aims at investigating the formation of deposits on finned tubes during nucleate pool boiling of CaSO{sub 4} solutions. The test finned tubes are low finned tubes with fin densities of 19 and 26 fins/in. made from Cu-Ni. The fouling experiments were carried out at atmospheric pressure for different heat fluxes ranging from 100 to 300 kW/m{sup 2} and a CaSO{sub 4} concentration of 1.6 g/L. For the sake of comparison, similar runs were performed with smooth stainless steel tubes. The results show that: (1) the fouling resistance decreases with increasing fin density, (2) fouling on the finned tubes was reduced with increasing nucleate boiling activity and (3) if any fouling layer occurred on the finned tubes it could be removed easily. (orig.)

  8. Airside performances of finned eight-tube heat exchangers

    Science.gov (United States)

    Li, Cheng; Li, Junming

    2016-11-01

    For applications in the relatively low temperature refrigeration systems with large constant temperature bath, the present work performed the experimental studies on the airside performances of the staggered finned eight-tube heat exchangers with large fin pitches. The airside heat transfer coefficients and pressure drops for three fin types and two fin pitches are obtained and analyzed. The heat transfer enhancement with louver fins is 11-16 % higher than the flat fins and that with sinusoidal corrugated fins is 1.1-3.4 % higher than the flat fins. Higher Re brings larger enhancement for various fins. Fin pitches show weak influence on heat transfer for eight tube rows. However, effects of fin pitch on heat transfer for both the sinusoidal corrugation and the louvered fin are larger than the flat fins and they are different from those for N ≤ 6. Airside Colburn j factor are compared with previous and it could be concluded that the airside j factor is almost constant for finned tube heat exchangers with eight tubes and large fin pitches, when Re is from 250 to 2500. The results are different from previous studies for fewer tube rows.

  9. Role of Pectoral Fin Flexibility in Robotic Fish Performance

    Science.gov (United States)

    Bazaz Behbahani, Sanaz; Tan, Xiaobo

    2017-08-01

    Pectoral fins play a vital role in the maneuvering and locomotion of fish, and they have become an important actuation mechanism for robotic fish. In this paper, we explore the effect of flexibility of robotic fish pectoral fins on the robot locomotion performance and mechanical efficiency. A dynamic model for the robotic fish is presented, where the flexible fin is modeled as multiple rigid elements connected via torsional springs and dampers. Blade element theory is used to capture the hydrodynamic force on the fin. The model is validated with experimental results obtained on a robotic fish prototype, equipped with 3D-printed fins of different flexibility. The model is then used to analyze the impacts of fin flexibility and power/recovery stroke speed ratio on the robot swimming speed and mechanical efficiency. It is found that, in general, flexible fins demonstrate advantages over rigid fins in speed and efficiency at relatively low fin-beat frequencies, while rigid fins outperform flexible fins at higher frequencies. For a given fin flexibility, the optimal frequency for speed performance differs from the optimal frequency for mechanical efficiency. In addition, for any given fin, there is an optimal power/recovery stroke speed ratio, typically in the range of 2-3, that maximizes the speed performance. Overall, the presented model offers a promising tool for fin flexibility and gait design, to achieve speed and efficiency objectives for robotic fish actuated with pectoral fins.

  10. Blue shark Prionace glauca fin-to-carcass-mass ratios in Spain and implications for finning ban enforcement.

    Science.gov (United States)

    Santana-Garcon, J; Fordham, S; Fowler, S

    2012-04-01

    This study examines the processing of fins from blue sharks Prionace glauca caught by the Spanish longline fleet and landed in Vigo, Spain, and implications of these practices for enforcing the E.U. ban on shark finning, which relies on a maximum fin-to-carcass-mass ratio. Two major sources of variability in fin-to-carcass ratios are quantified and discussed: (1) the fin set (type and number of fins retained from each shark) and (2) the cutting method used to separate fins from carcasses. The significant differences in fin-to-carcass-mass ratios between fin sets or cutting procedure demonstrates that the ratio limit is problematic and, conclusively, in order to facilitate proper enforcement, fishermen should be required to land all sharks with the fins still naturally attached to the bodies. © 2012 The Authors. Journal of Fish Biology © 2012 The Fisheries Society of the British Isles.

  11. Performance study of a fin and tube heat exchanger with different fin geometry

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    This study analyses the effect of different fin geometries on the heat transfer and pressure loss characteristics of a fin and tube heat exchanger. A numerical investigation is carried out on liquid–gas type double-finned tube heat exchanger under cross-flow condition. Three different cross......-sections namely: a) Rectangular, b) Trapezoidal, c) Triangular are adopted to define the fin geometry. The CFD simulations are performed to incorporate coupled steady state conjugate heat transfer with the turbulent flow phenomenon for the Reynolds number in the range of 5000-13000. Dimensionless heat transfer...... and pressure loss characteristics such as Nusselt number, Euler number, and efficiency index are determined and utilized to compare the performance of different fin geometries. The results obtained from the models are verified using experimentally developed correlations. The results obtained from the numerical...

  12. Comparative Study of Effect of Fin Arrangement on Propulsion Performance of Bio-inspired Underwater Vehicles with Multiple SMA Fins

    Directory of Open Access Journals (Sweden)

    Jian-hui He

    2015-09-01

    Full Text Available A biologically inspired underwater vehicle (BIUV was built using multiple lightweight bio inspired shape memory alloy (SMA fins. An unsteady 3D computational fluid dynamics (CFD method using an unstructured, grid-based, and unsteady Navier-Stokes solver with automatic adaptive re-meshing was adopted to compute unsteady flow. The hydrodynamics of multiple fins at a certain Reynolds number (Re = Uc/ν, where U is the upstream flow velocity, c is the chord length, and ν is the kinematic viscosity was studied and simulated using CFD to estimate hydrodynamic forces and characterize flow and vortex patterns created by the fins. Two common arrangements of multiple fins on the BIUV were considered: a posterior fin that is parallel to the anterior fins (case 1 and a posterior fin that is perpendicular to the anterior fins (case 2. First, the influence of the distance between two anterior undulating fins on the propulsion performance of both arrangements of multiple fins on the BIUV was investigated. The effect of the distance between the anterior undulating fins and the posterior oscillating fin was also analysed. The length of the posterior oscillating fin was varied and the fin surface area was held constant (24 mm2 to illustrate the influence of this parameter. Finally, the effect of frequency, amplitude, and wave number of anterior undulating fins on the non-dimensional drag coefficient of the posterior oscillating fin was investigated. Based on the flow structures, the reasons for the different performances of the BIUV are discussed. BIUV performances largely depend on the arrangements of multiple fins and the gap between the fins. Dimension and kinematic parameters also affect the performance of the BIUV. The results provide a physical insight into the understanding of fin interaction in fish or BIUVs that are propelled by multiple fins.

  13. Heat Transfer Analysis of Fin Tube

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Woo-Jin [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Choi, Cheng-Ryul [ELSOLTEC Co., Yongin (Korea, Republic of)

    2015-10-15

    This paper describes a preliminary numerical analysis of fin tube used for a heat exchanger of the air-water cooling system. The internal flow in a fin tube is steam and the external of the fin is cooled by air. Cooling system in a nuclear power plant can be divided into two categories; 1) active pump driven system powered by alternating current and 2) passive cooling system drived by natural circulation phenomena. After the accident in Hukushima Nuclear Power Plants, the importance of the passive cooling system that can provide a long-term cooling of reactor decay heat during station blackout condition is emphasized. However, the effectiveness of passive cooling system based on cooling water is limited by the capacity of water storage tank. To overcome the limit due to the exhaustion of the cooling water, an natural convection air cooling system is proposed. As the air operated cooling system utilizes natural circulation phenomena of air, it does not require cooling water. However, the heat transfer area of the air operated cooling system should be increased much as the heat removal capacity per unit area is much lower than that of water cooling system. The air-water combined cooling system can resolve this excess increase of the heat transfer area in the air operated cooling system. This air-water cooling system can be also used in the passive containment cooling system. The effect of design parameters such as fin tube arrangement, the fin height, and pitch has been analyzed and the chimney effect on the simulation of heat transfer in a heat exchanger is evaluated. The internal flows in a fin tube heat exchanger for natural circulation flow condition and forced convection (suction) condition were investigated.

  14. Numerical Analysis of Mixed Convection through an Internally Finned Tube

    Directory of Open Access Journals (Sweden)

    Sachindra Kumar Rout

    2012-01-01

    Full Text Available Wall temperature of an internally finned tube has been computed numerically for different fin number, height, and shape by solving conservation equations of mass, momentum, and energy using Fluent 12.1 for a steady and laminar flow of fluid inside a tube under mixed flow condition. It has been found that there exists an optimum number for fins to keep the pipe wall temperature at a minimum. The fin height has an optimum value beyond which the wall temperature becomes insensitive to fin height. For a horizontal tube, under mixed flow condition, it is seen that the upper surface has higher average temperature than the lower surface. The impact of fin shape on the heat transfer rate shows that wall temperature is least for triangular-shaped fins, compared to rectangular- and T-shaped fins. In addition to the thermal characteristics, the pressure drop caused due to the presence of fins has also been studied.

  15. Morphological Considerations of Fish Fin Shape on Thrust Generation

    Directory of Open Access Journals (Sweden)

    Kenji Kikuchi

    2014-01-01

    Full Text Available In this study, we aimed to determine the relationship between thrust generation and fish fin shape. To compare the effect fin shape had on thrust generation, we categorized the morphological shapes of fish fins into equilateral polygonal shapes. Polygonal fins were used to generate thrust that depended only on shape. These fins were constructed of a hard elastic material to eliminate any influence of shape deformation. A servomotor with a reciprocal rotation moved a fin cyclically, and thrust was experimentally measured using a strain gage system. Thrust tended to be proportional to the inertia moment of a fin, which indicated difficulty with rotation. Moreover, this trend for thrust generation was directly related to the number of apexes of a polygonal fin. The force translated ratio, which was thrust divided by the force required for fin rotation, was evaluated to determine the hydrodynamic characteristics of fins. This finding showed that the force translated ratio of a fin increased with increased movable perimeter length. The greatest thrust was generated by a triangular fin rotated at its apex, which is often seen in general fish tail fins, whereas the hydrodynamic characteristics were the worst in polygonal fins.

  16. Classificação tecnológica de solos e resíduos industriais, com e sem tratamento térmico, para fins rodoviários Technological classification of soils and industrial residues with and without thermal treatment for forest road pavement

    Directory of Open Access Journals (Sweden)

    Carlos Cardoso Machado

    2003-10-01

    Full Text Available Estudou-se o comportamento mecânico das misturas solo-alcatrão, solo-cal-alcatrão e solo-cimento-alcatrão, com base nos ensaios de limites de liquidez e plasticidade, CBR, compressão simples e permeabilidade, visando a aplicabilidade destas em rodovias. Trabalhou-se com três amostras de solos (ETA, NV e VS, representativos das ocorrências da microrregião de Viçosa-MG. Foram empregados alcatrão, nos quantitativos de 0,25, 0,5, 1, 2, 4 e 6%, cal hidratada e cimento Portland, em conjunto com o alcatrão, na dosagem de 2%, considerando-se a energia do ensaio de compactação AASHTO Normal. A adição de alcatrão reduziu significativamente os valores de LL dos solos, mas com pouca variação nos valores de IP. Conclui-se que o alcatrão contribuiu para melhorar as características mecânicas e hidráulicas dos solos, para alguns tratamentos, não atingindo, entretanto, os padrões de resistência mecânica exigida pelo DNER para camadas de sub-base de pavimentos flexíveis. Quanto às misturas solo-cal-alcatrão e solo-cimento-alcatrão, constatou-se melhoria substancial nos parâmetros de resistência mecânica em relação aos solos, principalmente devido à ação cimentante da cal e do cimento, e que para alguns tratamentos esta ação foi potencializada pelo alcatrão, incidindo em resistência mecânica superior à das misturas solo-cal e solo-cimento. O alcatrão, em alguns tratamentos, ocasionou decréscimos na permeabilidade das misturas, com relação ao solo, de até dez vezes. O alcatrão mostrou ser um estabilizante de interesse para fins rodoviários apenas para determinadas condições, envolvendo tipo de solo e tipo e teor de alcatrão, o que indica que estudos nesta direção devem apresentar uma característica regional.The behavior of the mechanical mixtures soil-wood tar, soil-lime-wood tar and soil-cement-wood tar, based on the Atterberg limits California Bearing Ratio (CBR, Unconfined Compression Strength (UCS and

  17. Fin formation model during pre-roll ploughing of copper 3D outside fin tube

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The mechanism of pre-roll ploughing for 3D fins on the outside surface of copper tube was studied systematically, and especially the process and conditions of 3D fin formation were analyzed. The right mathematical model was also established. Based on the volume of fin ploughed out is equal to the volume of the metal extruded up by the extruding face of the tool, the relations between fin height, pre-roll ploughing feed and pre-roll ploughing depth have been achieved. With the increase of pre-roll ploughing depth which must be equal to groove depth, the fin height gradually becomes larger. There are different critical feeds with the various depths of pre-roll ploughing. The pre-roll ploughing feed is the critical one, the height of fin is largest. And when the feed is above the critical one, the fin height will reduce with the increase of feed. The theoretical analysis basically accords with experimental results.

  18. Propulsive performance of an under-actuated robotic ribbon fin.

    Science.gov (United States)

    Liu, Hanlin; Curet, Oscar M

    2017-06-02

    Many aquatic animals propelled by elongated undulatory fins can perform complex maneuvers and swim with high efficiency at low speeds. In this propulsion, one or multiple waves travel along an elastic fin composed of flexible rays. In this study, we explore the potential benefits or disadvantages of passive fin motion based on the coupling of fluid-structure interactions and elasto-mechanical responses of the undulatory fin. The motivation is to understand how an under-actuated undulating fin can modify its active and passive fin motion to effectively control the hydrodynamic force and propulsive efficiency. We study the kinematics and propulsive performance of an under-actuated ribbon fin using a robotic device. During two experimental sets for fully-actuated fin and under-actuated fin respectively, we measured fin kinematics, surge forces and power consumption. Our results show that under-actuated fin can generate smaller thrust but consume less power comparing to a fully-actuated counterpart. The thrust generated by an under-actuated fin scales similarly to a fully-actuated fin-linear with the enclosed area and quadratic with the relative velocity. Power consumption scales with cube of lateral tangential velocity. Furthermore, we find that the under-actuated fin can keep the same propulsive efficiency as the fully-actuated fin at low relative velocities. This finding has profound implications to both natural swimmers and underwater vehicles using undulating fin-based propulsion, as it suggests that they can potentially exploit passive fin motion without decrementing propulsive efficiency. For underwater vehicles with undulatory fins, an under-actuated design can greatly simplify the mechanical design and control complexity of a versatile propulsion system.

  19. El cine como realización del fin del arte

    Directory of Open Access Journals (Sweden)

    Juan Carlos Arias

    2006-01-01

    Full Text Available Muchos han afirmado que el ideal del arte defendido por el modernismo ha llegado a su fin. El relato fundado por el arte moderno ya no aplica para ciertas prácticas contemporáneas, lo cual ha llevado a pensar que, más allá de ser necesario un nuevo relato que dé cuenta del arte en sus diversas manifestaciones, hay que reconocer el fin de los relatos, la incapacidad de producir una nueva narrativa que reemplace a la modernista para incluir y legitimar las formas del arte hoy. Es este fin de las narrativas lo que podemos comprender, siguiendo a Arthur Danto, como fin del arte, concepto que designa el paso del arte moderno al arte contemporáneo. El objetivo de este texto es comprender qué sitio ocupa el cine dentro de este tránsito —que, más que cronológico, es conceptual—, al analizar las nociones de pureza e impureza en el arte.

  20. Fin width and height dependence of bipolar amplification in bulk FinFETs submitted to heavy ion irradiation

    Institute of Scientific and Technical Information of China (English)

    于俊庭; 陈书明; 陈建军; 黄鹏程

    2015-01-01

    FinFET technologies are becoming the mainstream process as technology scales down. Based on a 28-nm bulk p-FinFET device, we have investigated the fin width and height dependence of bipolar amplification for heavy-ion-irradiated FinFETs by 3D TCAD numerical simulation. Simulation results show that due to a well bipolar conduction mechanism rather than a channel (fin) conduction path, the transistors with narrower fins exhibit a diminished bipolar amplification effect, while the fin height presents a trivial effect on the bipolar amplification and charge collection. The results also indicate that the single event transient (SET) pulse width can be mitigated about 35%at least by optimizing the ratio of fin width and height, which can provide guidance for radiation-hardened applications in bulk FinFET technology.

  1. Investigation of negative bias temperature instability dependence on fin width of silicon-on-insulator-fin-based field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Young, Chadwin D., E-mail: chadwin.young@utdallas.edu; Wang, Zhe [Materials Science and Engineering, University of Texas at Dallas, 800 W. Campbell Road, Richardson, Texas 75080 (United States); Neugroschel, Arnost [Department of Electrical and Computer Enginering, University of Florida, Gainesville, Florida 32611 (United States); Majumdar, Kausik; Matthews, Ken; Hobbs, Chris [SEMATECH, Albany, New York 12203 (United States)

    2015-01-21

    The fin width dependence of negative bias temperature instability (NBTI) of double-gate, fin-based p-type Field Effect Transistors (FinFETs) fabricated on silicon-on-insulator (SOI) wafers was investigated. The NBTI degradation increased as the fin width narrowed. To investigate this phenomenon, simulations of pre-stress conditions were employed to determine any differences in gate oxide field, fin band bending, and electric field profile as a function of the fin width. The simulation results were similar at a given gate stress bias, regardless of the fin width, although the threshold voltage was found to increase with decreasing fin width. Thus, the NBTI fin width dependence could not be explained from the pre-stress conditions. Different physics-based degradation models were evaluated using specific fin-based device structures with different biasing schemes to ascertain an appropriate model that best explains the measured NBTI dependence. A plausible cause is an accumulation of electrons that tunnel from the gate during stress into the floating SOI fin body. As the fin narrows, the sidewall device channel moves in closer proximity to the stored electrons, thereby inducing more band bending at the fin/dielectric interface, resulting in a higher electric field and hole concentration in this region during stress, which leads to more degradation. The data obtained in this work provide direct experimental proof of the effect of electron accumulation on the threshold voltage stability in FinFETs.

  2. INCORPORAÇÃO DE RESÍDUOS VEGETAIS E SEUS EFEITOS SOBRE AS CARACTERÍSTICAS FÍSICO-MECÂNICAS DE MISTURAS DE SOLO-CIMENTO PARA FINS DE CONSTRUÇÃO RURAL PLANT RESIDUES INCORPORATION EFFECTS ON PHYSICAL AND MECHANICAL CHARACTERISTICS OF SOIL-CEMENT MIXTURES FOR AGRICULTURAL BUILDINGS PURPOSES

    Directory of Open Access Journals (Sweden)

    Marcos Fernandes Oliveira

    2007-12-01

    Full Text Available

    O presente trabalho teve como objetivo avaliar o efeito da adição da casca de arroz e da casca da semente do capim braquiária, sobre as propriedades físico-mecânicas de misturas de solo-cimento e conseqüente análise de sua viabilidade técnica com vistas à fabricação de materiais de construção alternativos para fins rurais. Para tal, os resíduos foram triturados, peneirados e tratados em solução de cal e o solo submetido aos ensaios de caracterização segundo normas brasileiras. Os resíduos foram adicionados em substituição ao cimento, variando os teores de cimento e de resíduo vegetal desde 100% de cimento e 0% de resíduo, até 60% de cimento e 40% de resíduo. Posteriormente foram moldados corpos-de-prova cilíndricos que foram submetidos aos ensaios de compressão simples, aos sete, 28 e 56 dias, e de capacidade de absorção de água, aos sete dias da moldagem. Após análise dos resultados, pôde-se concluir que as misturas obtidas a partir da substituição parcial do cimento por 10% de resíduos mostram-se viáveis como matéria-prima na fabricação de elementos construtivos não estruturais, tais como, blocos e tijolos prensados, destinados às construções e instalações rurais.

    PALAVRAS-CHAVE: Solo-cimento, resíduos vegetais, construções rurais.

    The aim of this research was to evaluate the effect of rice and Brachiaria brizantha husks on physical and mechanical properties of soil-cement mixtures and, consequently, to analyse their technical feasibility to manufacture alternative building materials for agricultural purposes. Husks were ground, sieved, and treated in lime solution and soil submitted to characterisation tests according to Brazilian standards. The plant residues were added in substitution to the cement. The cement content and

  3. Silicon LEDs in FinFET technology

    NARCIS (Netherlands)

    Piccolo, G.; Kuindersma, P.I.; Ragnarsson, L-A.; Hueting, R.J.E.; Collaert, N.; Schmitz, J.

    2014-01-01

    We present what to our best knowledge is the first forward operating silicon light-emitting diode (LED) in fin-FET technology. The results show near-infrared (NIR) emission around 1100 nm caused by band-to-band light emission in the silicon which is uniformly distributed across the lowly doped activ

  4. Room to high temperature measurements of flexible SOI FinFETs with sub-20-nm fins

    KAUST Repository

    Diab, Amer El Hajj

    2014-12-01

    We report the temperature dependence of the core electrical parameters and transport characteristics of a flexible version of fin field-effect transistor (FinFET) on silicon-on-insulator (SOI) with sub-20-nm wide fins and high-k/metal gate-stacks. For the first time, we characterize them from room to high temperature (150 °C) to show the impact of temperature variation on drain current, gate leakage current, and transconductance. Variation of extracted parameters, such as low-field mobility, subthreshold swing, threshold voltage, and ON-OFF current characteristics, is reported too. Direct comparison is made to a rigid version of the SOI FinFETs. The mobility degradation with temperature is mainly caused by phonon scattering mechanism. The overall excellent devices performance at high temperature after release is outlined proving the suitability of truly high-performance flexible inorganic electronics with such advanced architecture.

  5. Curvature-induced stiffening of a fish fin

    CERN Document Server

    Nguyen, Khoi; Bandi, Mahesh M; Venkadesan, Madhusudhan; Mandre, Shreyas

    2016-01-01

    Fish behaviour and its ecological niche require modulation of its fin stiffness. Using mathematical analyses of rayed fish fins, we show that curvature transverse to the rays is central to fin stiffness. We model the fin as rays with anisotropic bending that are connected by an elastic membrane. For fins with transverse curvature, external loads that bend the rays also splay them apart, which stretches the membrane. This coupling, between ray bending and membrane stretching, underlies the curvature-induced stiffness. A fin that appears flat may still exhibit bending-stretching coupling if the principal bending axes of adjacent rays are misaligned by virtue of intrinsic geometry, i.e. morphologically flat yet functionally curved. Analysis of the pectoral fin of a mackerel shows such functional curvature. Furthermore, as identified by our analyses, the mackerel's fin morphology endows it with the potential to modulate stiffness over a wide range.

  6. Embryonic development of fin spines in Callorhinchus milii (Holocephali); implications for chondrichthyan fin spine evolution.

    Science.gov (United States)

    Jerve, Anna; Johanson, Zerina; Ahlberg, Per; Boisvert, Catherine

    2014-01-01

    Fin spines are commonly known from fossil gnathostomes (jawed vertebrates) and are usually associated with paired and unpaired fins. They are less common among extant gnathostomes, being restricted to the median fins of certain chondrichthyans (cartilaginous fish), including chimaerids (elephant sharks) and neoselachians (sharks, skates, and rays). Fin spine growth is of great interest and relevance but few studies have considered their evolution and development. We investigated the development of the fin spine of the chimaerid Callorhinchus milii using stained histological sections from a series of larval, hatchling, and adult individuals. The lamellar trunk dentine of the Callorhinchus spine first condenses within the mesenchyme, rather than at the contact surface between mesenchyme and epithelium, in a manner more comparable to dermal bone formation than to normal odontode development. Trabecular dentine forms a small component of the spine under the keel; it is covered externally with a thin layer of lamellar trunk dentine, which is difficult to distinguish in sectioned adult spines. We suggest that the distinctive characteristics of the trunk dentine may reflect an origin through co-option of developmental processes involved in dermal bone formation. Comparison with extant Squalus and a range of fossil chondrichthyans shows that Callorhinchus is more representative than Squalus of generalized chondrichthyan fin-spine architecture, highlighting its value as a developmental model organism. © 2014 Wiley Periodicals, Inc.

  7. CFD Analysis of Plate Fin Tube Heat Exchanger for Various Fin Inclinations

    Directory of Open Access Journals (Sweden)

    Subodh Bahirat,

    2014-08-01

    Full Text Available ANSYS Fluent software is used for three dimensional CFD simulations to investigate heat transfer and fluid flow characteristics of six different fin angles with plain fin tube heat exchangers. The numerical simulation of the fin tube heat exchanger was performed by using a three dimensional numerical computation technique. Geometry of model is created and meshed by using ANSYS Workbench software. To solve the equation for the fluid flow and heat transfer analysis ANSYS FLUENT was used in the fin-tube heat exchanger. The fluid flow and heat transfer are simulated and result compared for both laminar and turbulent flow models k-epsilon and SST k-omega, with steady state solvers to calculate heat transfer, flow velocity and temperature fields of variable inclined fin angles (Ɵ = 00 ,100 , 200 , 300 , 400 ,500 . Model is validate by comparing the simulated value of velocity, temperature and colburn factor with experimental and numerical results investigated by WANG [1] and GHORI KIRAR [10]. Reasonable agreement is found between the simulations and other results, and the ANSYS Fluent software is sufficient for simulating the flow fields in tube fin heat exchanger.

  8. Film condensation of steam on externally finned horizontal tubes.

    OpenAIRE

    Flook, Frederick A.

    1985-01-01

    Approved for public release; distribution is unlimited Filmwise condensation measurements of steam were made on horizontal finned tubes under vacuum and near-atmospheric conditions. Data were obtained for copper tubes with fins of rectangular, triangular, trapezoidal, and parabolic cross sections, and for a commercially-available finned tube. A stainless steel finned tube was also tested to investigate the effect of thermal conductivity. Maximum enhancements of about 4.8 were obtained...

  9. Heat transfer in bundles of finned tubes in crossflow

    Energy Technology Data Exchange (ETDEWEB)

    Stasiulevicius, J.; Skrinska, A.; Zukauskas, A.; Hewitt, G.F.

    1986-01-01

    This book provides correlations of heat transfer and hydraulic data for bundles of finned tubes in crossflow at high Reynolds numbers. Results of studies of the effectiveness of the fin, local, and mean heat transfer coefficients are presented. The effect of geometric parameters of the fins and of the location of tubes in the bundle on heat transfer and hydraulic drag are described. The resistance of the finned tube bundles under study and other factors are examined.

  10. THERMAL EFFICIENCY ANALYSIS OF CROSS-FINNED TUBES

    OpenAIRE

    Лагутін, А.Ю.; П.Ф. Стоянов

    2015-01-01

    Finned heat exchangers are the basic type of heat exchanger employed in many industrial applications such as refrigeration, air conditioning and other thermal processes. This paper presents experimental research of air-side heat transfer of finned surfaces. Seven types of finned surfaces are employed in this study. Investigation describes temperature fields and temperature cooling air-flow changing in the inter-fin duct without taking into account tube section. Temperature difference in-betwe...

  11. Curvature-induced stiffening of a fish fin

    OpenAIRE

    Nguyen, Khoi; Yu, Ning; Bandi, Mahesh M.; Venkadesan, Madhusudhan; Mandre, Shreyas

    2016-01-01

    How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the ...

  12. NUMERICAL AND EXPERIMENTAL STUDIES OF INFLUENCE OF THE CAUDAL FIN SHAPE ON THE PROPULSION PERFORMANCE OF A FLAPPING CAUDAL FIN

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xi; SU Yu-min; WANG Zhao-li

    2011-01-01

    This article presents a comprehensive study of the effects of the caudal fin shape on the propulsion performance of a eandal fin in harmonic heaving and pitching.A numerical simulation based on an unsteady panel method was carried out to analyze the hydrodynamic performance of flapping caudal fins of three shapes (the whale caudal fin with the largest projected area, the dolphin caudal fin with the median projected area, and the tuna caudal fin with the smallest projected area).Then, a series of hydrodynamic experiments for three caudal fin shapes were performed.Both computational and experimental results indicate that the tuna caudal fin produces the highest efficiency.However the mean thrust coefficient of the tuna caudal fin is the smallest.It is found that although the mean thrust coefficient for the tuna caudal fin is not large, the input power of the tuna caudal fin is also quite small.So the tuna caudal fin achieves a high efficiency.

  13. An experimental investigation on the airside performance of fin-and-tube heat exchangers having slit fins under wet condition

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun [Incheon National University, Incheon (Korea, Republic of); Kim, Tae Hun [Samsung Electronics Co., Suwon (Korea, Republic of)

    2015-11-15

    In this study, the heat transfer and friction characteristics of the 5.3 mm O.D. slit-finned heat exchangers under wet condition have been experimentally investigated. Plain-finned heat exchangers having the same 5.3 mm O.D. tubes are also tested for comparison purpose. The effect of fin pitch on j and f factor is negligible. Slit fin samples yield higher j and f factors than plain fin samples. For one row configuration, the average f factor ratio between slit fin sample and plain fin sample is 2.18. The ratio increases to 2.41 for two row configuration, and to 2.65 for three row configuration. As for the j factor, the ratios are approximately the same (1.61, 1.70 and 1.71 for one, two and three row configuration). Both j and f factor increase as the number of tube row decreases. The same trend is observed for the plain fin samples. At high Reynolds numbers, the j/f ratios of the slit fin are approximately the same as those of the plain fin. At low Reynolds numbers, the j/f ratios of the slit fin are smaller than those of plain fin. Data are compared with existing correlations.

  14. Sizing-tube-fin space radiators

    Science.gov (United States)

    Peoples, J. A.

    1978-01-01

    Temperature and size considerations of the tube fin space radiator were characterized by charts and equations. An approach of accurately assessing rejection capability commensurate with a phase A/B level output is reviewed. A computer program, based on Mackey's equations, is also presented which sizes the rejection area for a given thermal load. The program also handles the flow and thermal considerations of the film coefficient.

  15. Composite hydrophilic coating for conditioner aluminum fins

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    To solve the so-called "white rust" and 'water bridge" problems of the aluminum fins for heat exchanger of automobile air conditioner, aimed at nationalizing the art of hydrophilic coating technology, the choice of coating forming and curing materials was investigated. By measuring the water contact angle, SEM surface scanning and ingredients analysis of the coating, optimal parameters and composition are acquired. The coating forming mechanisms of the composition was also expatiated. The coating obtained has good hydrophilic and other properties.

  16. Study on Thermo-Conductive Plastic Finned Tube Radiators

    Institute of Scientific and Technical Information of China (English)

    1997-01-01

    This paper discusses thermo-conductive plastic finned tube radiators used in water saving type power stations.First,the development of thermo-conductive plastics is introduced.Second,in order to determine the rational geometric dimensions of thermo-conductive plastic finned tubes,an objective function which takes the minimum volume of the consumed material for making finned tubes as an object is introduced.On the basis of the function,the economy comparison between thermo-conductive plastic finned tubes and metal finned tubes is conducted.

  17. Performance Prediction of Cross-Finned Tube Heat Exchangers

    Science.gov (United States)

    Kondou, Chieko; Senshu, Takao; Oguni, Kensaku

    The plane fin of a cross-finned tube heat exchangers is the basis for all kinds of fins used in air conditioners. In this paper, an improvement the dimensionless arrangements of pressure drop for plane fins was attempted. The detailed calculation results for all geometrical parameters, especially tube disposition, showed the reflecting to the effect of contracted flow in the existing equations of friction factor is insufficient. Therefore, an amendment for these equations was suggested. Further, the analogy between the revised friction factor and the Colburn's j factor was verified. In addition an approximate expression for the fin efficiency using wide parameters was devised.

  18. Asymmetrically doped stacked channel strained SOI FinFET

    Science.gov (United States)

    Dubey, Shashank; Kondekar, Pravin N.

    2017-02-01

    Strained SOI (SSOI) n-channel trigate FinFET is designed with asymmetrically doped stacked channels along the fin height. The OFF current is reduced with respect to lightly doped uniform SSOI FinFET because of band gap modification, originated between highly doped uniaxial strained and lightly doped Si fin. Through TCAD simulation it is observed that for the stacked devices the OFF current is reduced by more than 47%. The performances are also compared with highly doped uniform SSOI FinFETs and the results indicated that these devices have lesser random dopant variation at a moderate cost of ON and OFF current.

  19. Performance Evaluation of Plate-Fin-And Tube Heat Exchanger with Wavy Fins- A Review

    Directory of Open Access Journals (Sweden)

    Sandip S. Kale

    2014-09-01

    Full Text Available The plate fin-and-tube heat exchangers are widely used in variety of industrial applications, particularly in the heating, air-conditioning and refrigeration, HVAC industries. In most cases the working fluid is liquid on the tube side exchanging heat with a gas, usually air. It is seen that the performance of heat exchangers can be greatly increased with the use of unconventionally shaped flow passages such as plain, perforated offset strip, louvered, wavy, vortex generator and pin. The current study is focused on wavy-fin. The wavy surface can lengthen the path of airflow and cause better airflow mixing. In order to design better heat exchangers and come up with efficient designs, a thorough understanding of the flow of air in these channels is required. Hence this study focuses on the heat transfer and friction characteristics of the air side for wavy fin and tube heat exchanger.

  20. CFD Study of Pectoral Fins of Larval Zebrafish: Effect of Reynolds Number and Fin Bending in Fluid Structures and Transport

    Science.gov (United States)

    Islam, Toukir; Curet, Oscar M.

    2015-11-01

    Zebrafish exhibits significant changes in fin morphology as well as fin actuation during its physical development. In larval stage (Re ~ 10), they beat pectoral fins asymmetrically during slow swimming and prey tracking and a hypothesis suggests pectoral fin motion enhances fluid mixing to assist respiration. We performed a series of computational simulations to study effect of Reynolds number (Re) and pectoral fin kinematics in the fluid dynamics and mixing around a larval zebrafish. The CFD algorithm is based on a constraint formulation where the kinematics of the zebrafish are specified. We simulated experimental zebrafish kinematics at different Re (17 to 300) and considered variations on the fin kinematics to evaluate role of fin deformation in the fluid structures generated by the pectoral fins. Using Lagrangian Coherent Structures and Lagrangian fluid tracers, we identified distinctly dynamic fluid regions and found that mixing around the pectoral fin significantly increases with Re and fin bending enhance fluid mixing at low Re. However, as zebrafish matures and its Re increases, the need to beat the pectoral fins to enhance mixing is reduced.

  1. The Effects of Fin Collar Form on Heat Transfer Performance of Cross Fin-tube Heat Exchanger

    Science.gov (United States)

    Tsubaki, Koutaro; Miyara, Akio; Nagai, Yuma; Sasaki, Naoe; Mizuta, Yoshihiko

    A numerical study has been conducted to investigate effects of fin collar form of cross fin-tube heat exchangers on heat transfer performance. Two adjacent fin collars and a copper tube form a triangular space during the making process. And also end of the fin collar protrudes into air-side. The protruded end and triangular space affect on air-side heat convection and thermal resistance between the tube and fin collars, respectively. The increase in triangular space increases non-contact surface area between tube and fin collar, which affects to decrease heat transfer rate. The protruded end disturbs air-side flow and expands the surface of the fin collar. As a result of these two effects, heat transfer rate from the heat transfer tube increases. However, protruded end increases pressure loss of air-side.

  2. Parametric CFD Analysis to Study the Influence of Fin Geometry on the Performance of a Fin and Tube Heat Exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2016-01-01

    Heat transfer and pressure loss characteristics of a fin and tube heat exchanger are numerically investigated based on parametric fin geometry. The cross-flow type heat exchanger with circular tubes and rectangular fin profile is selected as a reference design. The fin geometry is varied using...... a design aspect ratio as a variable parameter in a range of 0.1-1.0 to predict the impact on overall performance of the heat exchanger. In this paper, geometric profiles with a constant thickness of fin base are studied. Three-dimensional, steady state CFD model is developed using commercially available...... are determined. The best performed geometric fin profile based on the higher heat transfer and lower pressure loss is predicted. The study provides insights into the impact of fin geometry on the heat transfer performance which help escalate the understanding of heat exchanger designing and manufacturing...

  3. Heat Transfer of Tube-fin Heat Exchanger Having Parallel Louver Continuous Fins

    Science.gov (United States)

    Take-Uchi, Masaaki; Yamada, Jun; Tanaka, Jun-Ichirou

    Heat transfer from tubes has been numerically simulated in a fan coil unit for an airconditioning equipment. The array of tubes has parallel louver continuous fins, perpendicular to staggered round tubes. Quite a few of slits divide plates into many strips, which are offsetted, so that the heat transfer will be augmented from the plate to the air flow. On the other hand, the conduction of heat in the platemight be prevented with these slits. The conduction retardation due to slit is estimated, and the simulation shows that the retardation is not serious for present fins.

  4. Undulating fins produce off-axis thrust and flow structures.

    Science.gov (United States)

    Neveln, Izaak D; Bale, Rahul; Bhalla, Amneet Pal Singh; Curet, Oscar M; Patankar, Neelesh A; MacIver, Malcolm A

    2014-01-15

    While wake structures of many forms of swimming and flying are well characterized, the wake generated by a freely swimming undulating fin has not yet been analyzed. These elongated fins allow fish to achieve enhanced agility exemplified by the forward, backward and vertical swimming capabilities of knifefish, and also have potential applications in the design of more maneuverable underwater vehicles. We present the flow structure of an undulating robotic fin model using particle image velocimetry to measure fluid velocity fields in the wake. We supplement the experimental robotic work with high-fidelity computational fluid dynamics, simulating the hydrodynamics of both a virtual fish, whose fin kinematics and fin plus body morphology are measured from a freely swimming knifefish, and a virtual rendering of our robot. Our results indicate that a series of linked vortex tubes is shed off the long edge of the fin as the undulatory wave travels lengthwise along the fin. A jet at an oblique angle to the fin is associated with the successive vortex tubes, propelling the fish forward. The vortex structure bears similarity to the linked vortex ring structure trailing the oscillating caudal fin of a carangiform swimmer, though the vortex rings are distorted because of the undulatory kinematics of the elongated fin.

  5. Function of dorsal fins in bamboo shark during steady swimming.

    Science.gov (United States)

    Maia, Anabela; Wilga, Cheryl A

    2013-08-01

    To gain insight into the function of the dorsal fins in white-spotted bamboo sharks (Orectolobiformes: Hemiscyillidae) during steady swimming, data on three-dimensional kinematics and electromyographic recordings were collected. Bamboo sharks were induced to swim at 0.5 and 0.75 body lengths per second in a laminar flow tank. Displacement, lag and angles were analyzed from high-speed video images. Onset, offset, duration, duty cycle and asynchrony index were calculated from three muscle implants on each side of each dorsal fin. The dorsal fins were displaced more laterally than the undulating body. In addition, the dorsal tips had larger lateral displacement than the trailing edges. Increased speed was accompanied by an increase in tail beat frequency with constant tail beat amplitude. However, lateral displacement of the fins and duration of muscle bursts remained relatively constant with increased speed. The range of lateral motion was greater for the second dorsal fin (mean 33.3°) than for the first dorsal fin (mean 28.4°). Bending within the fin was greater for the second dorsal fin (mean 43.8°) than for the first dorsal fin (mean 30.8°). Muscle onset and offset among implants on the same side of each dorsal fin was similar. Three-dimensional conformation of the dorsal fins was caused by interactions between muscle activity, material properties, and incident flow. Alternating bilateral activity occurred in both dorsal fins, further supporting the active role of these hydrofoils in thrust production during steady swimming. The dorsal fins in bamboo sharks are capable of thrust production during steady swimming and do not appear to function as stabilizing structures.

  6. Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Lai-bing Jia; Shi-wu Zhang; Jie Yang; K.H.Low

    2007-01-01

    Biomimetic design employs the principles of nature to solve engineering problems.Such designs which are hoped to be quick,efficient,robust,and versatile,have taken advantage of optimization via natural selection.In the present research.an environment-friendly propulsion system mimicking undulating fins of stingray was built.A non-conventional method was considered to model the flexibility of the fins of stingray.A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin.The driving linkages were used to form a mechanical fin consisting of several fin segments,which are able to produce undulations,similar to those produced by the actual fins.Owing to the modularity of the design of the mechanical fin,various undulating patterns can be realized.Some qualitative observations,obtained by experiments,predicted that the thrusts produced by the mechanical fin are different among various undulating patterns.To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system.Here,four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics(CFD)method.An unstructured,grid-based,unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles.The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into lift and thrust.The pressure force and friction force were also computed throughout the swimming cycle.Finally,vortex contour maps of these four basic fin undulating patterns were displayed and compared.

  7. Proteomic analysis of zebrafish caudal fin regeneration.

    Science.gov (United States)

    Saxena, Sandeep; Singh, Sachin K; Lakshmi, Mula G Meena; Meghah, Vuppalapaty; Bhatti, Bhawna; Swamy, Cherukuvada V Brahmendra; Sundaram, Curam S; Idris, Mohammed M

    2012-06-01

    The epimorphic regeneration of zebrafish caudal fin is rapid and complete. We have analyzed the biomechanism of zebrafish caudal fin regeneration at various time points based on differential proteomics approaches. The spectrum of proteome changes caused by regeneration were analyzed among controls (0 h) and 1, 12, 24, 48, and 72 h postamputation involving quantitative differential proteomics analysis based on two-dimensional gel electrophoresis matrix-assisted laser desorption/ionization and differential in-gel electrophoresis Orbitrap analysis. A total of 96 proteins were found differentially regulated between the control nonregenerating and regenerating tissues of different time points for having at least 1.5-fold changes. 90 proteins were identified as differentially regulated for regeneration based on differential in-gel electrophoresis analysis between the control and regenerating tissues. 35 proteins were characterized for its expression in all of the five regenerating time points against the control samples. The proteins identified and associated with regeneration were found to be directly allied with various molecular, biological, and cellular functions. Based on network pathway analysis, the identified proteome data set for regeneration was majorly associated in maintaining cellular structure and architecture. Also the proteins were found associated for the cytoskeleton remodeling pathway and cellular immune defense mechanism. The major proteins that were found differentially regulated during zebrafish caudal fin regeneration includes keratin and its 10 isoforms, cofilin 2, annexin a1, skeletal α1 actin, and structural proteins. Annexin A1 was found to be exclusively undergoing phosphorylation during regeneration. The obtained differential proteome and the direct association of the various proteins might lead to a new understanding of the regeneration mechanism.

  8. FinTech Market Development Perspectives

    OpenAIRE

    Kalmykova Ekaterina; Ryabova Anna

    2016-01-01

    Fast development of technologies has led to emergence of the new market – FinTech – which is very attractive for investors today. By now this market has a great number of different concepts: P2P-crediting, E-wallets, Bitcoins, mPOS-acquiring, T-commerce, mobile banks, etc. Many of these tools have already heavily entered our ordinary life. People can obtain any credits through special services on the Internet from other users without participation of banks, pay by credit card using mobile dev...

  9. Cu-P-Sn-Ni钎料真空钎焊MGH956合金的研究%Research of brazing MGH956 alloy with Cu-Ni-Sn-Ni filler metal in vacuum

    Institute of Scientific and Technical Information of China (English)

    刁秀晖; 李小强; 张民爱; 屈盛官; 董重里

    2016-01-01

    为扩展Cu-P基钎料在连接MGH956合金中的应用,采用新型Cu-P-Sn-Ni钎料对MGH956合金在800~890℃进行了真空钎焊,研究了不同钎焊温度和保温时间对焊缝组织及力学性能的影响.结果表明:在所研究的钎焊温度范围内保温5 min均可获得成形效果良好的钎焊接头,其主要由钎缝中心区和界面反应层组成,其中,钎缝中心区由α( Cu)固溶体基体和化合物Cu3 P+( Fe,Ni)3 P+FeCr组成,反应层由α( Fe)固溶体、Fe3 P和Cu3 P组成;随着钎焊温度的升高,反应层厚度逐渐增加,钎缝中心区中的化合物Cu3 P+( Fe,Ni)3 P+FeCr的形态也随之发生明显改变;各钎焊温度下获得的钎焊接头经室温拉伸,断裂均发生在钎缝中心区,断口形貌呈现韧性和脆性的混合断裂特征.830℃钎焊5 min的接头抗拉强度最大,为510.3 MPa,达到了母材抗拉强度的70.9%.%To expand the application of Cu-P based filler metal for joining MGH956 superalloy, a noval Cu-P-Sn-Ni based filler metal was developed and it was used to vacuum braze MGH956 superalloy in temperature range of 800-890℃. The effect of brazing temperature and holding time on the microstructures and mechanical properties of the joints were investigated in detail. The results show that all the brazed joints have good appearance in the brazing temperature range for 5 min. The brazed joint mainly consists of a central brazed layer and two interfacial reaction layers close to MGH956 superalloy. The central brazed layer consists of the matrix of α (Cu) solid solution and the compounds of Cu3P, (Fe,Ni)3P and FeCr. The interfacial reaction layer was composed of α (Fe) solid solution, Fe3P and Cu3P. With the increasing of brazing temperature, the thickness of reaction layer increases, and the shape of the compounds in the central brazed layer also changes markedly. The room temperature tensile fracture of all the joints occur in the central brazed layers, and the fracture is characterized as ductile and brittle mode. The maximum tensile strength of the joint brazed at 830℃for 5 min can be obtained at 510.3 MPa, which is 70.9% of the MGH956 parent alloy.

  10. El fin del mundo según Lacunza

    Directory of Open Access Journals (Sweden)

    Fredy Parra C.

    2000-01-01

    Full Text Available El artículo presenta el pensamiento milenarista del jesuita chileno Manuel Lacunza (1731-1801 en torno al fin del mundo. Se indaga la visión del autor sobre el fin del siglo, el fin del milenio y su concepto de bienaventuranza eterna. El lacunzismo sostiene que antes del final de la historia se espera un reino terrestre del Mesías Jesucristo en el cual tendrán pleno cumplimiento las promesas de vida y justicia que Dios ha hecho a la humanidad. En este contexto se explica que para Lacunza el reino mesiánico (milenio comienza con una transformación de la naturaleza que transita a una etapa de mayor perfección y que el mundo nuevo que adviene es mejor que el presente no solamente en lo moral sino también en lo físico y material. Asimismo, el universo renovado, acabada toda generación y corrupción, participará de la plenitud eterna y, tras la resurrección universal, los bienaventurados gozarán juntos eternamente de la contemplación del mundo transfigurado y de la comunión con Dios. Siempre se trata de una transformación de la materia de mal en bien, o de bien en mejor. Se excluye, clara y expresamente, la idea de un "fin del mundo" como aniquilación del mismo.The article presents the millienarist thought of the Chilean Jesuit Manuel Lacunza (1731-1801 regarding the end of the world. It looks into the author’s views on the end of the century, the end of the milliemium, and his concept of eternal beatitude. Lacunza affirms that an earthly kingdom of Jesus Christ the Messiah will come before the end of the history, in which, all the promises of life and justice made by God will have full accomplishment. Within this context, it is easy to undestand that for Lacunza, the messianic kingdom (Millenium starts with a transformation of nature, which moves onto a stage of greater perfection, and that this coming renewed world, is much better than the present one, not only in the moral aspect, but also in the physical and material aspects

  11. Estructura, metodología y escritura del Trabajo de Fin de Máster

    Directory of Open Access Journals (Sweden)

    María Isabel Cervera Fernández

    2012-03-01

    Full Text Available Estructura, metodología y escritura del Trabajo de Fin de Máster es una obra escrita por Gemma Muñoz-Alonso, docente de la Facultad de Filosofía de la Universidad Complutense de Madrid, y autora de numerosos escritos en torno a cuestiones metodológicas no sólo en el campo de la documentación filosófica, sino en el campo de las humanidades en general. La obra ofrece al lector, al docente, al estudiante, a cualquier persona que necesite o desee realizar un trabajo de investigación en el espacio de un Máster, cualquiera que sea su temática, una serie de orientaciones y herramientas para alcanzar el éxito en la empresa acometida, a saber: en la elaboración, escritura y defensa del Trabajo de Fin de Máster.

  12. Anatomy and early development of the pectoral girdle, fin, and fin spine of sturgeons (Actinopterygii: Acipenseridae).

    Science.gov (United States)

    Dillman, Casey B; Hilton, Eric J

    2015-03-01

    Acipenseriformes hold an important place in the evolutionary history of bony fishes. Given their phylogenetic position as extant basal Actinopterygii, it is generally held that a thorough understanding of their morphology will greatly contribute to the knowledge of the evolutionary history and the origin of diversity for the major osteichthyan clades. To this end, we examined comparative developmental series from the pectoral girdle in Acipenser fulvescens, A. medirostris, A. transmontanus, and Scaphirhynchus albus to document, describe, and compare ontogenetic and allometric differences in the pectoral girdle. We find, not surprisingly, broad congruence between taxa in the basic pattern of development of the dermal and chondral elements of the pectoral girdle. However, we also find clear differences in the details of structure and development among the species examined in the dermal elements, including the clavicle, cleithrum, supracleithrum, posttemporal, and pectoral-fin spine. We also find differences in the internal fin elements such as the distal radials as well as in the number of fin rays and their association with the propterygium. Further, there are clear ontogenetic differences during development of the dermal and chondral elements in these species and allometric variation in the pectoral-fin spine. The characters highlighted provide a suite of elements for further examination in studies of the phylogeny of sturgeons. Determining the distribution of these characters in other sturgeons may aid in further resolution of phylogenetic relationships, and these data highlight the role that ontogenetic and comparative developmental studies provide in systematics.

  13. Air cooling effect of fins on a Honda shine bike

    Directory of Open Access Journals (Sweden)

    Padhiyar Abhesinh J

    2015-05-01

    Full Text Available The main of aim of this work is to study various researches done in past to improve heat transfer rate of cooling fins by changing cylinder block fin geometry. Low rate of heat transfer through cooling fins is the main problem in this type of cooling. So efficiency of the engine is increase by increase the heat transfer. Examples of direct air cooling in modern automobiles are rare. The most common example is the commercials Automobile bike like a Honda Shine, Bajaj bike, Honda splendor etc. It is conclude about shape try to this fins is more effectively heat transfer in Honda shine bike compare to existing fins. After FEA Analysis it checking on fin whether efficiency of heat transfer increases or not. This work validation with Experimental and Mathematical.

  14. Selection of plain or segmented finned tubes for heat recovery

    Energy Technology Data Exchange (ETDEWEB)

    Reid, D.R.; Taborek, Jerry (Fintube Corp. (United States))

    1994-01-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded ''plain'' fins were generally used in the past - until the high-frequency resistance welding technology permitted the cost-effective manufacture of segmented fins. The main advantage of the segmented fin design is that it permits higher heat flux and hence smaller, lighter units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight and cost per unit area, favour the segmented fin design, a few other considerations, such as fouling, ease of cleaning and availability of dependable design methods, have to be considered. This article analyses the performance parameters that affect the selection of either fin type. (4 figures, 1 table, 10 references) (Author)

  15. Thermal Analysis of Fin and Tube Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Ms N. B. Rairker

    2014-06-01

    Full Text Available This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed that as the width of fin increases thermal stresses on fin also increases. Likewise for tube, by varying diameter of tube different values of stress are obtained. It is also observed at full valve position maximum thermal stresses are induced on fin as well as tube.

  16. Boiling of HFE-7100 on a Straight Pin Fin

    Institute of Scientific and Technical Information of China (English)

    Z. W. Liu; W.W. Lin; D.J. Lee; J.P. Hsu

    2001-01-01

    This paper deals with an experimental investigation of pin fin boiling of saturated and subcooled HFE-7100 under atmospheric pressure. Fin base temperature and heat flux data are measured along with the fin tip temperature. The basic features of boiling stability of HFE-7100 boiling on pin fin had been reported for the first time. For a given liquid/heating surface combination there exist upper steady-state (USS) branch and lower steady-state (LSS)branch, and a large, unstable regime located in between. Zones with different stability characteristics are mapped according to boiling on fins with different aspect ratios. Liquid subcooling can largely enhance heat transfer performance. A longer fin can provide a safer operation.

  17. Improve seawater cooling with titanium finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    O' Donnell J. (High Performance Tube, Inc., Warren, NJ (United States))

    1992-10-01

    Seawater offers an endless supply of cooling water for these coastal processing facilities. But users must address seawater's corrosive nature in selecting construction materials for heat exchangers. Copper-nickel or carbon steel tubing fails continually under seawater service. This paper reports that titanium tubes, once thought to be too expensive a material for heat exchanger tubing, offer a unique combination of high material strength, excellent resistance to corrosion, and endurance to erosion by seawater. Titanium's superior physical properties in combination with enhanced surface area of low finned tubing perform the same heat duty with half the lineal footage of traditional heat exchanger tubes. High density low finned tubes multiply heat transfer capacity by a factor of two compared to plain tube. The technology applies in retrofit and original equipment manufacture (OEM) situations. It works best when the ratio of heat transfer coefficients is 2:1 or higher between the seawater coolant and shellside flow being cooled.

  18. Turbulent Flow Simulations in Complex Multilouvered Fins

    Science.gov (United States)

    Tafti, Danesh

    2000-11-01

    Air-side resistance makes up roughly 80resistance in compact heat exchangers. Multilouvered fins find widespread use in the automotive and HVAC industry for heat transfer augmentation. We will describe the computational methodology for simulating the complex three-dimensional geometry and present results at a Reynolds number of 1100 based on louver pitch and the average flow velocity. The three-dimensionality in the louver geometry occurs along the height of the fin, where the angled louver transitions to the flat landing and joins with the tube surface. The transition region is characterized by a swept leading edge and decreasing flow area between louvers. Results show the formation of spanwise vortices at the leading edge of the angled portion of the louver which convect downstream in the vicinity of the louver surface. Further there is evidence of a separate louver wake instability which interacts with the vortices shed from the leading edge. In the transition region, a high energy streamwise vortex jet is formed. The jet forms in the vicinity of the louver junction with the flat landing and is drawn under the louver in the transition region. The passage of the jet in the vicinity of the louver surface produces a high pressure stagnant zone directly under the jet with a net effect of reducing heat transfer. On the other hand, the top surface of the louver in the transition region experiences high velocities in the vicinity of the surface and exhibits much higher heat transfer coefficients than the bottom surface.

  19. Bioelectric signaling regulates size in zebrafish fins.

    Directory of Open Access Journals (Sweden)

    Simon Perathoner

    2014-01-01

    Full Text Available The scaling relationship between the size of an appendage or organ and that of the body as a whole is tightly regulated during animal development. If a structure grows at a different rate than the rest of the body, this process is termed allometric growth. The zebrafish another longfin (alf mutant shows allometric growth resulting in proportionally enlarged fins and barbels. We took advantage of this mutant to study the regulation of size in vertebrates. Here, we show that alf mutants carry gain-of-function mutations in kcnk5b, a gene encoding a two-pore domain potassium (K(+ channel. Electrophysiological analysis in Xenopus oocytes reveals that these mutations cause an increase in K(+ conductance of the channel and lead to hyperpolarization of the cell. Further, somatic transgenesis experiments indicate that kcnk5b acts locally within the mesenchyme of fins and barbels to specify appendage size. Finally, we show that the channel requires the ability to conduct K(+ ions to increase the size of these structures. Our results provide evidence for a role of bioelectric signaling through K(+ channels in the regulation of allometric scaling and coordination of growth in the zebrafish.

  20. Filmwise condensation of steam on low integral-finned tubes

    OpenAIRE

    Georgiadis, Ioannis V.

    1984-01-01

    Approved for public release; distribution is unlimited Filmwise condensation heat-transfer measurements if steam were made on horizontal tubes under vacuum and near-atmospheric pressures. Data were taken for a smooth tube and for 21 tubes which contained rectangularly-shaped, low integral fins. The fin geometry was systematically varied in order to investigate the dependence of the steam-side heat-transfer coefficient on fin spacing, thickness and height. The condensation process was fo...

  1. Fuzzy-PID controlled lift feedback fin stabilizer

    Institute of Scientific and Technical Information of China (English)

    LIANG Yan-hua; JIN Hong-zhang; LIANG Li-hua

    2008-01-01

    Conventional PID controllers are widely used in fin stabilizer control systems,but they have time-variations,nonlinearity,and uncertainty influencing their control effects.A lift feedback fuzzy-PID control method was developed to better deal with these problems,and this lift feedback fin stabilizer system was simulated under different sea condition.Test results showed the system has better anti-rolling performance than traditional fin-angle PID control systems.

  2. Augmentation of Condensation Heat Transger by Finning of Tubes

    OpenAIRE

    1992-01-01

    This paper summarizes experimental and theoretical studies that have been performed in our laboratory to enhance condensation heat transfer on horizontal tubes and tube bundles by use of fins. Use of a drainge strip is proved to be very effective in further enhancing condensation heat transfer on the horizontal finned tube. Effects of fin geometry and tube arrangement on the condensation heat transfer performance of the tube bundle are investigated. A theoretical model is proposed to predict ...

  3. Thermal Analysis of Fin and Tube Heat Exchanger

    OpenAIRE

    2014-01-01

    This paper studied experimentally the effect of heat transfer of fin and tube type heat exchanger for different mass flow rate of fluid. The thermal stresses induced on fin and tube is also studied by ansys software at steady state condition by changing the width of fin and diameter of tube. Readings were taken experimentally by changing mass flow rate of fluid at respective temperatures. Comparison was done on theoretically and experimentally obtained results. It is observed ...

  4. Large Scale Density Estimation of Blue and Fin Whales (LSD)

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...sensors, or both. The goal of this research is to develop and implement a new method for estimating blue and fin whale density that is effective over...develop and implement a density estimation methodology for quantifying blue and fin whale abundance from passive acoustic data recorded on sparse

  5. Impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and device performance of Ge fin field-effect transistors

    Science.gov (United States)

    Mizubayashi, Wataru; Noda, Shuichi; Ishikawa, Yuki; Nishi, Takashi; Kikuchi, Akio; Ota, Hiroyuki; Su, Ping-Hsun; Li, Yiming; Samukawa, Seiji; Endo, Kazuhiko

    2017-02-01

    We investigated the impacts of plasma-induced damage due to UV light irradiation during etching on Ge fin fabrication and the device performance of Ge fin field-effect transistors (Ge FinFETs). UV light irradiation during etching affected the shape of the Ge fin and the surface roughness of the Ge fin sidewall. A vertical and smooth Ge fin could be fabricated by neutral beam etching without UV light irradiation. The performances of Ge FinFETs fabricated by neutral beam etching were markedly improved as compared to those of Ge FinFETs fabricated by inductively coupled plasma etching, in which the UV light has an impact.

  6. Lightweight Radiator Fins for Space Nuclear Power Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase 1 project shall investigate concept radiator fins that incorporate novel carbon materials for improved performance of segmented high temperature...

  7. Curvature-induced stiffening of a fish fin.

    Science.gov (United States)

    Nguyen, Khoi; Yu, Ning; Bandi, Mahesh M; Venkadesan, Madhusudhan; Mandre, Shreyas

    2017-05-01

    How fish modulate their fin stiffness during locomotive manoeuvres remains unknown. We show that changing the fin's curvature modulates its stiffness. Modelling the fin as bendable bony rays held together by a membrane, we deduce that fin curvature is manifested as a misalignment of the principal bending axes between neighbouring rays. An external force causes neighbouring rays to bend and splay apart, and thus stretches the membrane. This coupling between bending the rays and stretching the membrane underlies the increase in stiffness. Using three-dimensional reconstruction of a mackerel (Scomber japonicus) pectoral fin for illustration, we calculate the range of stiffnesses this fin is expected to span by changing curvature. The three-dimensional reconstruction shows that, even in its geometrically flat state, a functional curvature is embedded within the fin microstructure owing to the morphology of individual rays. As the ability of a propulsive surface to transmit force to the surrounding fluid is limited by its stiffness, the fin curvature controls the coupling between the fish and its surrounding fluid. Thereby, our results provide mechanical underpinnings and morphological predictions for the hypothesis that the spanned range of fin stiffnesses correlates with the behaviour and the ecological niche of the fish. © 2017 The Author(s).

  8. Grid Fin Stabilization of the Orion Launch Abort Vehicle

    Science.gov (United States)

    Pruzan, Daniel A.; Mendenhall, Michael R.; Rose, William C.; Schuster, David M.

    2011-01-01

    Wind tunnel tests were conducted by Nielsen Engineering & Research (NEAR) and Rose Engineering & Research (REAR) in conjunction with the NASA Engineering & Safety Center (NESC) on a 6%-scale model of the Orion launch abort vehicle (LAV) configured with four grid fins mounted near the base of the vehicle. The objectives of these tests were to 1) quantify LAV stability augmentation provided by the grid fins from subsonic through supersonic Mach numbers, 2) assess the benefits of swept grid fins versus unswept grid fins on the LAV, 3) determine the effects of the LAV abort motors on grid fin aerodynamics, and 4) generate an aerodynamic database for use in the future application of grid fins to small length-to-diameter ratio vehicles similar to the LAV. The tests were conducted in NASA Ames Research Center's 11x11-foot transonic wind tunnel from Mach 0.5 through Mach 1.3 and in their 9x7-foot supersonic wind tunnel from Mach 1.6 through Mach 2.5. Force- and moment-coefficient data were collected for the complete vehicle and for each individual grid fin as a function of angle of attack and sideslip angle. Tests were conducted with both swept and unswept grid fins with the simulated abort motors (cold jets) off and on. The swept grid fins were designed with a 22.5deg aft sweep angle for both the frame and the internal lattice so that the frontal projection of the swept fins was the same as for the unswept fins. Data from these tests indicate that both unswept and swept grid fins provide significant improvements in pitch stability as compared to the baseline vehicle over the Mach number range investigated. The swept fins typically provide improved stability as compared to the unswept fins, but the performance gap diminished as Mach number was increased. The aerodynamic performance of the fins was not observed to degrade when the abort motors were turned on. Results from these tests indicate that grid fins can be a robust solution for stabilizing the Orion LAV over a wide

  9. Computation of Unsteady Flow Past a Biomimetic Fin

    Institute of Scientific and Technical Information of China (English)

    Hao Liu; Naomi Kato

    2004-01-01

    The unsteady hydrodynamics of a biomimetic fin attached to a cylindrical body has been studied numerically using a computational fluid dynamic (CFD) simulator based on an in-house solver of the Navier-Stokes equations, combined with a recently developed multi-block, overset grid method. The fin-body CFD model is based on a mechanical pectoral fin device, which consists of a cylindrical body and an asymmetric fin and can mimic flapping, rowing and feathering motions of the pectoral fins in fishes. First the multi-block, overset grid method incorporated into the NS solver was verified through an extensive study of unsteady flows past a single fin undergoing rowing and feathering motion. Then unsteady flows past the biomimetic fin-body model undergoing the same motions were computed and compared with the measurements of forces of the mechanical pectoral fin, which shows good agreement in both time-varying and time-averaged hydrodynamic forces. The relationship between force generation and vortex dynamics points to the importance of the match in fin kinematics between power and recovery strokes and implies that an optimal selection of parameters of phase lags between and amplitudes of rowing and feathering motions can improve the performance of labriform propulsion in terms of either maximum force generation or minimum mechanical power.

  10. fgf20 is essential for initiating zebrafish fin regeneration.

    Science.gov (United States)

    Whitehead, Geoffrey G; Makino, Shinji; Lien, Ching-Ling; Keating, Mark T

    2005-12-23

    Epimorphic regeneration requires the presence or creation of pluripotent cells capable of reproducing lost organs. Zebrafish fin regeneration is mediated by the creation of blastema cells. Here, we characterize the devoid of blastema (dob) mutant that fails fin regeneration during initial steps, forms abnormal regeneration epithelium, and does not form blastema. This mutation has no impact on embryonic survival. Dob results from an fgf20a null mutation, Y148S. Fgf20a is expressed during initiation of fin regeneration at the epithelial-mesenchymal boundary and later overlaps with the blastema marker msxb. Thus, fgf20a has a regeneration-specific requirement, initiating fin regeneration, and controlling blastema formation.

  11. Effect of Fin Geometry on Condensation of R134a in a Staggered Bundle of Horizontal Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsk; Usami, Keiichiro

    Experimental results are presented that show the effect of fin geometry on condensation of refrigerant R134a in a staggered bundle of horizontal fined tubes. Two kinds of conventional low-fin tubes and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 8 to 23 kg/m2s and the condensation temperature difference from 1.5 to 12 K. In most cases, the highest performance was obtained by one of the three-dimensional fin tubes. In the case of high mass velocity and high film Reynolds number, however, the highest performance was obtained by one of the low-fin tubes. The results were compared with previous experimental results for bundles of smooth tubes and low-fin tubes.

  12. Flexibilidad laboral: ¿fin del trabajo permanente?

    Directory of Open Access Journals (Sweden)

    Carmen Añez Hernández

    2016-05-01

    Full Text Available Los trabajos transitorios o atípicos, siguen posicionándose y funcionando trastocando la protección del sistema de regulación y protección del trabajo permanente. De ahí, la importancia de reflexionar teóricamente sobre el tema. Para su desarrollo se plantean los siguientes objetivos: demostrar que la flexibilización laboral ha incidido en la ruptura de las relaciones laborales, caracterizar como la subcontratación laboral encubre dichas relaciones, analizar el despido laboral y sus consecuencias en los trabajadores. El artículo se desarrolló teóricamente, especialmente tomando como referencia autores como: Bravo (2010, Quintero (2010, González (2012 De La Garza (2007, Ugarte (2007, entre otros, lo cual permitió analizar la temática abordada. Los resultados reflejan que dicha estrategia está impulsando la agudización de las condiciones precarias de los derechos laborales, con lo cual se está ante un capitalismo irracional, que tiene como propósito que los trabajadores sufraguen los efectos de las pretensiones de los capitalistas por conseguir mayores tasas de ganancia y niveles más altos de productividad. En consecuencia, la flexibilización de las relaciones laborales está destinada a ocultar los derechos de los trabajadores, agudizar el despido laboral, y propiciar el fin de un trabajo permanente.

  13. First discovery of a primitive coelacanth fin fills a major gap in the evolution of lobed fins and limbs.

    Science.gov (United States)

    Friedman, Matt; Coates, Michael I; Anderson, Philip

    2007-01-01

    The fossil record provides unique clues about the primitive pattern of lobed fins, the precursors of digit-bearing limbs. Such information is vital for understanding the evolutionary transition from fish fins to tetrapod limbs, and it guides the choice of model systems for investigating the developmental changes underpinning this event. However, the evolutionary preconditions for tetrapod limbs remain unclear. This uncertainty arises from an outstanding gap in our knowledge of early lobed fins: there are no fossil data that record primitive pectoral fin conditions in coelacanths, one of the three major groups of sarcopterygian (lobe-finned) fishes. A new fossil from the Middle-Late Devonian of Wyoming preserves the first and only example of a primitive coelacanth pectoral fin endoskeleton. The strongly asymmetrical skeleton of this fin corroborates the hypothesis that this is the primitive sarcopterygian pattern, and that this pattern persisted in the closest fish-like relatives of land vertebrates. The new material reveals the specializations of paired fins in the modern coelacanth, as well as in living lungfishes. Consequently, the context in which these might be used to investigate evolutionary and developmental relationships between vertebrate fins and limbs is changed. Our data suggest that primitive actinopterygians, rather than living sarcopterygian fishes and their derived appendages, are the most informative comparators for developmental studies seeking to understand the origin of tetrapod limbs.

  14. Fin o metamorfosis de la escuela

    Directory of Open Access Journals (Sweden)

    José Joaquín Brunner

    1996-10-01

    Full Text Available El autor adhiere a la idea de que la escuela una es una de las matrices de la modernidad por cuanto separa la transmisión cultural de cualquier soporte físico (escritura, radicándola en el propio proceso de escolarización: su gramática consistiría en redes de clasificación del conocimiento, siendo el orden escolar esencialmente un procedimiento; el juego que juega la escuela es el de la obtención de los usos de adquisición del conocimiento. De esta forma el “fin de la escritura” como tecnología predominante del conocimiento, significara el conocimiento de una nueva era de escolarización.

  15. Laminar heat transfer characteristics of internally finned tube with sinusoidal wavy fin

    Science.gov (United States)

    Lin, M.; Tian, L.; Wang, Q. W.

    2011-06-01

    Comparative numerical study of laminar heat transfer characteristics of annular tubes with sinusoidal wavy fins has been conducted both experimentally and numerically with Re = 299-1,475. The uniform heat flux is imposed on the tube outside wall surface. Two tube materials (copper and stainless steel) are considered. It is found that the fluid temperature profile is not linear but convex along the flow direction due to the axial heat conduction in tube wall, and the effects of axial heat conduction on the heat transfer decreases with an increase in Reynolds number or decrease in tube wall thermal conductivity. The axial distributions of local Nusselt number could reach periodically fully developed after 3-5 cycles. The convectional data reduction method based on the traditional method should be improved for tube with high thermal conductivity or low Reynolds numbers, Otherwise, the heat transfer performance of internally finned tube may be underestimated.

  16. Fin efficiency analysis of convective straight fins with temperature dependent thermal conductivity using variational iteration method

    Energy Technology Data Exchange (ETDEWEB)

    Coskun, Safa Bozkurt [Department of Civil Engineering, Nigde University, 51245 Nigde (Turkey)], E-mail: sbcoskun@nigde.edu.tr; Atay, Mehmet Tarik [Department of Mathematics, Nigde University, 51245 Nigde (Turkey)

    2008-12-15

    For enhancing heat transfer between primary surface and the environment, utilization of radiating extended surfaces are common. Especially for large temperature differences; variable thermal conductivity has a strong effect on performance of such a surface. In this paper, variational iteration method is used to analyze the efficiency of convective straight fins with temperature dependent thermal conductivity. VIM produces analytical expressions for the solution of nonlinear differential equations. In order to show the effectiveness of variational iteration method (VIM), the results obtained from VIM analysis is compared with available solutions obtained using Adomian decomposition method (ADM) and the results from finite element analysis. This work assures that VIM is a promising method for the efficiency analysis of convective straight fin problems.

  17. Experimental Validation of Elliptical Fin-Opening Behavior

    Directory of Open Access Journals (Sweden)

    James M. Garner

    2003-01-01

    Full Text Available An effort to improve the performance of ordnance has led to the consideration of the use of folding elliptical fins for projectile stabilization. A second order differential equation was used to model elliptical fin deployment history and accounts for: deployment with respect to the geometric properties of the fin, the variation in fin aerodynamics during deployment, the initial yaw effect on fin opening, and the variation in deployment speed based on changes in projectile spin. This model supports tests conducted at the Transonic Experimental Facility, Aberdeen Proving Ground examining the opening behavior of these uniquely shaped fins. The fins use the centrifugal force from the projectile spin to deploy. During the deployment, the fin aerodynamic forces vary with angle-of-attack changes to the free stream. Model results indicate that projectile spin dominates the initial opening rates and aerodynamics dominate near the fully open state. The model results are examined to explain the observed behaviors, and suggest improvements for later designs.

  18. Dehumidification in greenhouses by condensation on finned pipes

    NARCIS (Netherlands)

    Campen, J.C.; Bot, G.P.A.

    2001-01-01

    In this study, an experimental dehumidifying system for greenhouses is tested. The system uses finned pipes fixed under the gutter of the greenhouse. The pipes are cooled below the dewpoint of the greenhouse air by cold water. The humid air passes the pipe and fins by natural convection and

  19. F-16 Ventral Fin Buffet Alleviation Using Piezoelectric Actuators

    Science.gov (United States)

    2009-09-01

    mode shapes of the test fin, a scanning laser vibrometer using PolyTec R© software version 8.61 was used to measure and analyze the frequency...fin. The PolyTec R© software application recorded and processed the measurements of the laser vibrometer and provided the natural frequencies and mode

  20. Vortex interactions with flapping wings and fins can be unpredictable

    NARCIS (Netherlands)

    Lentink, D.; Heijst, van G.J.F.; Muijres, F.T.; Leeuwen, van J.L.

    2010-01-01

    As they fly or swim, many animals generate a wake of vortices with their flapping fins and wings that reveals the dynamics of their locomotion. Previous studies have shown that the dynamic interaction of vortices in the wake with fins and wings can increase propulsive force. Here, we explore whether

  1. Defective fin regeneration in medaka fish (Oryzias latipes) with hypothyroidism.

    Science.gov (United States)

    Sekimizu, Koshin; Tagawa, Masatomo; Takeda, Hiroyuki

    2007-07-01

    Wild-type medaka are known to have remarkable capabilities of fin, or epimorphic, regeneration. However, a hypothyroid mutant, kamaitachi (kmi), frequently suffers from injury in fins, suggesting an important role of thyroid hormone in fin regeneration. This led us to examine the relationship between thyroid hormone and fin regeneration using medaka as a model. For this, we first set up a medaka experimental system in which the rate of regeneration was statistically analyzed after caudal fin amputation under normal and hypothyroid conditions. As expected, the regeneration of amputated caudal fins was delayed in hypothyroid kmi -/- mutants. We then examined wild-type medaka with thiourea-induced hypothyroidism to evaluate the requirement of thyroid hormone during epimorphic fin regeneration. The results demonstrate that the growth rate of regenerates was much reduced in severely hypothyroid medaka throughout the regeneration period. This reduction in regenerative rate was recovered by exogenous administration of L-thyroxine. The present study is thus the first to report the direct involvement of thyroid hormone in teleost fin regeneration, and provides a basic framework for future molecular and genetic analyses.

  2. FinFET modeling for IC simulation and design

    CERN Document Server

    Hu, Chenming; Lu, Darsen D

    2015-01-01

    This book is the first to explain FinFET modeling for IC simulation and the industry standard - BSIM-CMG - describing the rush in demand for advancing the technology from planar to 3D architecture, as now enabled by the approved industry standard. The book gives a strong foundation on the physics and operation of FinFET, details aspects of the BSIM-CMG model such as surface potential, charge and current calculations, and includes a dedicated chapter on parameter extraction procedures, providing a step-by-step approach for the efficient extraction of model parameters. With this book you will learn: * Why you should use FinFET* The physics and operation of FinFET* Details of the FinFET standard model (BSIM-CMG)* Parameter extraction in BSIM-CMG* FinFET circuit design and simulation * Authored by the lead inventor and developer of FinFET, and developers of the BSIM-CM standard model, providing an experts' insight into the specifications of the standard* The first book on the industry-standard FinFET model - BSIM...

  3. Effective Heat Transfer Enhancement in Finned Tube Heat Exchanger with Different Fin Profiles

    Directory of Open Access Journals (Sweden)

    J.A.Livingston1 , P. Selvakumar2

    2013-04-01

    Full Text Available During cross flow in a heat exchanger, heat transfer in the front portion of the tube is more compared to back portion of the tube. This is due to less formation of vortices at the backside of the tube. For uniform heat transfer to take place throughout the tube, it is necessary to increase the vortex formation at the rear side of the tube. The aim of this study is to explore the possibilities of improving the flow structure and thereby increasing uniform heat transfer around the tubes by introducing special type of fin arrangement over the tubes. The effect of shape and orientation of the fin on vortex generation and respective heat transfers are studied numerically. It have been identified that by introducing special type of fin arrangement over the tube there is a possibility for increase the vortex formation at the rear portion of the tube, which significantly leads to creation of uniform heat transfer all around the tube.

  4. Heat transfer to finned tubes exposed to hot waste gas

    Energy Technology Data Exchange (ETDEWEB)

    Scholand, E.; Kremer, H.

    1975-05-01

    Transfer of heat by forced convection to finned tubes, particularly to those with an elliptical center pipe, is described. These pipes are used in gas-fired water heaters, boilers, and heat exchangers. Finned tubes in a test tunnel were exposed to a stream of waste gas from a gas/air mixture at different Reynolds numbers. Mathematical relationships showing the dependence of the Nusselt number on the Reynolds number and on the geometry of the tubes were derived. The single pipe showed a significant drop in the heat-transfer coefficient as the gap between fins became closer. The results of the measurement of heat transfer by forced convection to finned tubes were expressed in a standard form for all tubes. The same heat transfer law can be applied to electrically heated finned tubes exposed to a stream of cooling air.

  5. Research on swimming by undulatory long dorsal fin propulsion

    Institute of Scientific and Technical Information of China (English)

    WANG Gnangming; SHEN Lincheng; WU Yonghui

    2007-01-01

    The kinematics of steady forward swimming of Gymnarchus niloticus is described. The geometric features of the body and locomotive characteristic and parameters of the flexible dorsal fin are discussed. On the basis of observation and experimental data, a simplified kinematic model on loco- motion of the undulatory long dorsal fin propulsion is pro- moted. The hydromechanical performances of the undulatory long dorsal fin propeller of G. Niloticus are estimated with the large-amplitude elongated-body theory. The hydromechani- cal efficiency of the undulatory long dorsal fin system ranged from 81.664% to 86.420% over a speed range of 0.728- 0.985 length·s-1. It is suggested that the undulatory long dorsal fin propulsion is an adaptation to swimming with high hydromechanical efficiency.

  6. Numerical and Experimental Research on Modular Oscillating Fin

    Institute of Scientific and Technical Information of China (English)

    Yong-hua Zhang; Yan Song; Jie Yang; K. H. Low

    2008-01-01

    Fishes are famous for their ability to position themselves accurately even in turbulent flows. This ability is the result of the coordinated movement of fins which extend from the body. We have embarked on a research program designed to develop an agile and high efficient biologically inspired robotic fish based on the performance of hybrid mechanical fins. To accomplish this goal, a mechanical ray-like fin actuated by Shape Memory Alloy (SMA) is developed, which can realize both oscillatory locomotion and undulatory locomotion. We first give a brief introduction on the mechanical structure of our fin and then carr yout theoretic analysis on force generation. Detailed information of these theoretical results is later revealed by Computational Fluid Dynamic (CFD), and is final validated by experiments. This robotic fin has potential application as a propulsor for future underwater vehicles in addition to being a valuable scientific instrument.

  7. AGENDA POLÍTICA DEL MOVIMIENTO DE MUJERES: DEMANDAS DE FIN DE SIGLO

    OpenAIRE

    González Suárez, Mirta

    2013-01-01

    El movimiento de mujeres costarricenses de fin de siglo ha llegado a una maduración consensual en torno a puntos tales como la equidad por medio de cuotas de representación política, la responsabilidad paterna, así como la necesidad de desarrollar políticas públicas con perspectiva de género. Estas y otras demandas fueron publicadas entre 1995 a 2000 y constituyen una importante retroalimentación para la academia y la sociedad en general. La Agenda de Mujeres Costarricenses (1997) presenta lo...

  8. El trabajo de fin de grado como evaluador de las competencias profesionales del enfermero generalista

    OpenAIRE

    Meneses Monroy, Alfonso

    2011-01-01

    La adaptación de las enseñanzas universitarias al Espacio Europeo de Educación Superior (EEES) ha conllevado cambios importantes en el proceso de enseñanza – aprendizaje. Entre estos figuran el diseño de los planes de estudio en base a competencias y la finalización de los estudios de Grado con un Trabajo Fin de Grado (TFG) que debe servir para que el estudiante demuestre que ha adquirido todas las competencias de la titulación. Partiendo de este planteamiento se ha llevado a cabo una revisi...

  9. Evaluating the Fin-ray Trajectory Tracking of Bio-inspired Robotic Undulating Fins via an Experimental-numerical Approach

    Directory of Open Access Journals (Sweden)

    Xiaojia Xiang

    2014-07-01

    Full Text Available In the past decade, biomimetic undulating fin propulsion has been one of the main topics considered by scientists and researchers in the field of robotic fish. This technology is inspired by the biological wave-like propulsion of ribbon-finned fish. The swimming modes have aquatic application potentials with greater manoeuvrability, less detectable noise or wake and better efficiency at low speeds. The present work concentrates on the evaluation of fin-ray trajectory tracking of biorobotic undulating fins at the levels of kinematics and hydrodynamics by using an experimental-numerical approach. Firstly, fin-ray tracking inconsistence between the desired and actual undulating trajectories is embodied with experimental data of the fin prototype. Next, the dynamics' nonlinearity is numerically and analytically unveiled by using the computational fluid dynamics (CFD method, from the viewpoint of vortex shedding and the hydro-effect. The evaluation of fin-ray tracking performance creates a good basis for control design to improve the fin-ray undulation of prototypes.

  10. ¿El principio del fin o el fin del principio? - Apuntes para una revolución

    Directory of Open Access Journals (Sweden)

    Dr. Ángel Luis Acosta Romero

    1998-01-01

    Full Text Available Al final del segundo milenio nos encontramos, sin duda, en una encrucijada histórica. Y no creemos que se trate sólo, aunque también, de un tópico repetido, y, casi siempre, adornado con tintes apocalípticos. Una encrucijada es un cruce de caminos, es decir, la duda y la apertura a distintas posibilidades. La duda, es cierto, nos obliga elegir. La libertad, en este caso, se nos impone. Debemos elegir y debemos hacerlo siendo conscientes de nuestros límites y de nuestras potencialidades. La crisis de la sociedad -de un modelo de sociedad- refleja y es reflejada por la crisis del conocimiento. Ya sabemos que el sujeto y el objeto se configuran mutuamente y no pueden ser aislados artificialmente. Afrontar la revolución en el conocimiento es afrontar, al mismo tiempo, una revolución política, es decir, una revolución integral, en la que el hombre (la humanidad se reconozca en su devenir complejo (homo sapiens/demens le llama Morin.

  11. Experimental Investigation of Heat Transfer and Pressure Drop Characteristics of H-type Finned Tube Banks

    OpenAIRE

    2014-01-01

    H-type finned tube heat exchanger elements maintain a high capacity for heat transfer, possess superior self-cleaning properties and retain the ability to effect flue gas waste heat recovery in boiler renovations. In this paper, the heat transfer and pressure drop characteristics of H-type finned tube banks are studied via an experimental open high-temperature wind tunnel system. The effects of fin width, fin height, fin pitch and air velocity on fin efficiency, convective heat transfer coe...

  12. Ha vuelto para mirarnos

    OpenAIRE

    2008-01-01

    En cada entrega analizaremos un cuadro, mirándolo con ojos matemáticos. Con esa particular mirada, fruto de nuestra propia (de)formación. Y desde ese punto de vista haremos paseos por el arte y las matemáticas. Espero que el lector, como hago yo mismo, disfrute descubriendo más allá de lo que a simple vista distinguiría cualquiera. Al fin de cuentas, el arte, como las matemáticas, han sido creados para hacernos disfrutar.

  13. Film condensation of HCFC-123 on in-line bundles of horizontal finned tubes. Effect of fin geometry. Suihei fin tsuki kan no gobanme kangun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. (Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study); Kim, K. (Kyushu University, Fukuoka (Japan)); Ishikawa, Y. (Otsuka Pharmaceutical Co. Ltd., Tokyo (Japan))

    1994-06-25

    Theoretical analysis and experiments were carried out in regard to the condensation of HCFC-123 vapor on a horizontal finned tube. The previous paper described the theoretical analysis on the film condensation in a tube nest with low-fins. In this study, approximate expressions of heat transfer coefficient for a newly proposed high-performance finned tubes are suggested and compared with the experimental results. In the test, HCFC-123 vapor was flowed from the upper part of the tube nest arranged in squares of 3 rows and 15 layers (tube pitch: 22mm), and was condensed on the tube surface. The liquid film formation was observed, and the heat transfer properties were measured. Two kinds of conventional low-fin tubes and two kinds of finned tubes of which shape is similar to the newly proposed ones were tested. One of the new finned tubes showed the highest heat transfer performance, which was about 85% higher than that of the conventional low-fin (26 fpi) tube. The theoretical model for condensation in the previous paper was correspondent with the experimental data at low vapor speed and low condensate inundation rate. 14 refs., 14 figs., 4 tabs.

  14. FinTech Market Development Perspectives

    Directory of Open Access Journals (Sweden)

    Kalmykova Ekaterina

    2016-01-01

    Full Text Available Fast development of technologies has led to emergence of the new market – FinTech – which is very attractive for investors today. By now this market has a great number of different concepts: P2P-crediting, E-wallets, Bitcoins, mPOS-acquiring, T-commerce, mobile banks, etc. Many of these tools have already heavily entered our ordinary life. People can obtain any credits through special services on the Internet from other users without participation of banks, pay by credit card using mobile devices, and get information about expenses and incomes according to the card anywhere in the world. Users do not need to go to banks anymore and to spend their time for credit arrangements, currency exchange, to look for ATMs to remove cash. Purchases on the Internet can be paid not only in rubles, but also in new digital currency. These tools make life easier, however, they pose a serious threat for banks. Now, bank institutions should create more convenient and utility services for the clients to keep clients. Therefore, bank and credit systems start to change actively.

  15. The hydrodynamics of ribbon-fin propulsion during impulsive motion.

    Science.gov (United States)

    Shirgaonkar, Anup A; Curet, Oscar M; Patankar, Neelesh A; Maciver, Malcolm A

    2008-11-01

    Weakly electric fish are extraordinarily maneuverable swimmers, able to swim as easily forward as backward and rapidly switch swim direction, among other maneuvers. The primary propulsor of gymnotid electric fish is an elongated ribbon-like anal fin. To understand the mechanical basis of their maneuverability, we examine the hydrodynamics of a non-translating ribbon fin in stationary water using computational fluid dynamics and digital particle image velocimetry (DPIV) of the flow fields around a robotic ribbon fin. Computed forces are compared with drag measurements from towing a cast of the fish and with thrust estimates for measured swim-direction reversals. We idealize the movement of the fin as a traveling sinusoidal wave, and derive scaling relationships for how thrust varies with the wavelength, frequency, amplitude of the traveling wave and fin height. We compare these scaling relationships with prior theoretical work. The primary mechanism of thrust production is the generation of a streamwise central jet and the associated attached vortex rings. Under certain traveling wave regimes, the ribbon fin also generates a heave force, which pushes the body up in the body-fixed frame. In one such regime, we show that as the number of waves along the fin decreases to approximately two-thirds, the heave force surpasses the surge force. This switch from undulatory parallel thrust to oscillatory normal thrust may be important in understanding how the orientation of median fins may vary with fin length and number of waves along them. Our results will be useful for understanding the neural basis of control in the weakly electric knifefish as well as for engineering bio-inspired vehicles with undulatory thrusters.

  16. Water flow and fin shape polymorphism in coral reef fishes.

    Science.gov (United States)

    Binning, Sandra A; Roche, Dominique G

    2015-03-01

    Water flow gradients have been linked to phenotypic differences and swimming performance across a variety of fish assemblages. However, the extent to which water motion shapes patterns of phenotypic divergence within species remains unknown. We tested the generality of the functional relationship between swimming morphology and water flow by exploring the extent of fin and body shape polymorphism in 12 widespread species from three families (Acanthuridae, Labridae, Pomacentridae) of pectoral-fin swimming (labriform) fishes living across localized wave exposure gradients. The pectoral fin shape of Labridae and Acanthuridae species was strongly related to wave exposure: individuals with more tapered, higher aspect ratio (AR) fins were found on windward reef crests, whereas individuals with rounder, lower AR fins were found on leeward, sheltered reefs. Three of seven Pomacentridae species showed similar trends, and pectoral fin shape was also strongly related to wave exposure in pomacentrids when fin aspect ratios of three species were compared across flow habitats at very small spatial scales (back lagoon). Unlike fin shape, there were no intraspecific differences in fish body fineless ratio across habitats or depths. Contrary to our predictions, there was no pattern relating species' abundances to polymorphism across habitats (i.e., abundance was not higher at sites where morphology is better adapted to the environment). This suggests that there are behavioral and/or physiological mechanisms enabling some species to persist across flow habitats in the absence of morphological differences. We suggest that functional relationships between swimming morphology and water flow not only structure species assemblages, but are yet another important variable contributing to phenotypic differences within species. The close links between fin shape polymorphism and local water flow conditions appear to be important for understanding species' distributions as well as patterns of

  17. Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations

    Directory of Open Access Journals (Sweden)

    John S. Palmisano

    2012-01-01

    Full Text Available A method was devised to vector propulsion of a robotic pectoral fin by means of actively controlling fin surface curvature. Separate flapping fin gaits were designed to maximize thrust for each of three different thrust vectors: forward, reverse, and lift. By using weighted combinations of these three pre-determined main gaits, new intermediate hybrid gaits for any desired propulsion vector can be created with smooth transitioning between these gaits. This weighted gait combination (WGC method is applicable to other difficult-to-model actuators. Both 3D unsteady computational fluid dynamics (CFD and experimental results are presented.

  18. Effect of vapor velocity during condensation on horizontal finned tubes

    OpenAIRE

    Hopkins, Charles Louis III

    1988-01-01

    Approved for public release; distribution is unlimited Heat-transfer measurements were made for condensation of R-113 and steam on a smooth tube and on three finned tubes with rectangular shape fins. These tubes had a fin height and width of 1.0 mm and spacings of 0.25, 1.5, and 4.0 mm (tubes A, B, and C respectively) . Data were taken by increasing the vapor velocity from 0.4 to 1.9 m/s for R-113 and 4.8 to 31.3 m/s for steam. For both fluids, the improvement of the c...

  19. Application of cross finned tubes in latent heat storages

    Energy Technology Data Exchange (ETDEWEB)

    Schwind, H.; Wolff, D. (Dortmund Univ. (Germany, F.R.). Lehrstuhl fuer Anlagentechnik); Brose, J. (Dortmund Univ. (Germany, F.R.). Arbeitsgruppe Chemieapparatebau)

    1978-01-01

    Heat storages, utilizing the latent heat of materials have in comparison with sensible heat storages the two fundamental advantages of small storage volumes and constant temperatures during charge and discharge. Known storage systems in the field of industrial heating may be replaced advantageous by latent heat storage systems. A new latent heat storage, applying storage material around vertical arranged cross finned tubes is presented. It results in good heat transfer rates and avoids degredation and stratification of salthydrates during operation. The scaling-up of a single cross finned tube to a compact unit with plate fins seems to be practicable without problems. Some experimental results are presented.

  20. FinTech – What's in a Name?

    OpenAIRE

    Zavolokina, Liudmila; Dolata, Mateusz; Schwabe, Gerhard

    2016-01-01

    FinTech, the word which originates from marriage of “finance” and “technology”, designates currently a novel, innovative and emerging field which attracts attention from the publicity. At the moment there is no universal understanding and definition of FinTech in the research, however, the topic is widely addressed by the English- and German-speaking press. In this study we aim to make insights into how the press and other popular media understand and frame FinTech, discussing definitions tha...

  1. FinTech – What's in a Name?

    OpenAIRE

    Zavolokina, Liudmila; Dolata, Mateusz; Schwabe, Gerhard

    2016-01-01

    FinTech, the word which originates from marriage of “finance” and “technology”, designates currently a novel, innovative and emerging field which attracts attention from the publicity. At the moment there is no universal understanding and definition of FinTech in the research, however, the topic is widely addressed by the English- and German-speaking press. In this study we aim to make insights into how the press and other popular media understand and frame FinTech, discussing definitions tha...

  2. El efecto fin de mes en los principales mercados accionarios latinoamericanos

    Directory of Open Access Journals (Sweden)

    Werner Kristjanpoller Rodríguez

    2015-01-01

    Full Text Available En los mercados accionarios es frecuente encontrar anomalías de calendario, las cuales han sido objeto de diversos estudios en estas últimas décadas, incluso demostrándose que algunas de ellas a través del tiempo han ido desapareciendo. En este contexto, este artículo analiza una de estas anomalías, el efecto fin de mes, tanto en rendimiento como en volatilidad en los mercados accionarios de seis países latinoamericanos; a saber, Brasil, México, Chile, Colombia, Perú y Argentina en el periodo 1993-2011. La importancia de este estudio radica en poder probar si el efecto de fin de mes ha ido desapareciendo o aún persiste, ya que algunos efectos calendario en mercados accionarios desarrollados se han ido disipando. Los hallazgos de esta investigación, que se realizó de acuerdo con los tres periodos diferentes definidos en la literatura para analizar el impacto fin de mes, muestran que la mayoría de los países bajo análisis obtienen rendimientos anormales positivos en los días asociados al cambio de mes y también muestran anomalías en la volatilidad. Esta investigación no solamente analiza los índices característicos de cada mercado, sino que también las acciones en particular de cada uno, dotándolo de una muestra mucho mayor y exigente al momento de concluir sobre la existencia del fenómeno. También se incluye un análisis de volumen de transacción para verificar ciertas hipótesis del fenómeno asociadas a mayor flujo de efectivo.

  3. Computational analysis of heat transfer and pressure drop performance for internally finned tubes with three different longitudinal wavy fins

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Qiu-Wang; Lin, Mei; Zeng, Min; Tian, Lin [Xi' an Jiaotong University, State Key Laboratory of Multiphase Flow in Power Engineering, Xi' an, Shaanxi (China)

    2008-12-15

    Turbulent pressure drop and heat transfer characteristics in tubes with three different kinds of internally longitudinal fin patterns (interrupted wavy, sinusoidal wavy and plain) are numerically investigated for Re=904-4,520. The channel velocity, temperature, and turbulence fields are obtained to discern the mechanisms of heat transfer enhancement. Numerical results indicate that the steady and spatially periodic growth and disruption of cross-sectional vortices occur near the tube/fin walls along the streamwise locations. The thermal boundary layers near the tube/fin surfaces are thereby periodically interrupted, with heat transfer near the recirculation zones being enhanced. The overall heat transfer coefficients in wavy channels are higher than those in a plain fin channel, while with larger pressure drop penalties. At the same waviness, the interrupted wavy fin tube could enhance heat transfer by 72-90%, with more than 2-4 times of pressure drop penalty. Among the fins studied, the sinusoidal wavy fin has the best comprehensive performance. (orig.)

  4. Effect of Fin Geometry on Condensation Heat Transfer of Refrigerant R134a on Enhanced Finned Tubes

    Science.gov (United States)

    Takahashi, Hiroyuki; Saeki, Chikara; Koyama, Shigeru

    This paper presents the experimental results on the outside condensation heat tral1sfer coefficient of horizontal enhanced filmed tubes. Three different fin geometry types of three-dimensional enhanced finned tubes were tested. A low-fin-tube (LFT) 19 fin-per-inch (fpi) was also tested for reference. Experimental refrigerant used was R134a. The heat tral1sfer coefficient test was carried out at a condensing temperature of 40°C, at a cooling water velocity of 1.5 m/s, and the heat flux of 10 to 110 kW/m2K. The outside condensation heat transfer coefficient of all three dimensional enhanced finned tubes were approximately 1.9 times higher than that of LFTl9fpi at high heat flux range. In low heat flux range, the enhanced finned tube of small circumferential segmentation pitches at the fin tip was shown the highest outside heat transfer coefficient for all tubes tested.

  5. ¿El fin de la globalización? La crisis económica de Estados Unidos

    OpenAIRE

    Pablo Pozzi; Fabio Nigra

    2010-01-01

    El presente trabajo asume una perspectiva no tradicional de la globalización, al entenderse por ella un proceso impulsado por Estados Unidos para mantener su lugar de preeminencia a escala internacional. Para tal fin, los sucesivos gobiernos de ese país impulsaron un conjunto de medidas, tanto en lo doméstico como en la política internacional, que condujeron a la actual situación de crisis económica mundial, y buscaron una modificación del patrón de acumulación de capital, de forma tal que, a...

  6. Babel. Revista de Libros: formular el propio presente entre los finales y el fin

    Directory of Open Access Journals (Sweden)

    Mariana Catalin

    2013-08-01

    Full Text Available El presente artículo realiza un abordaje de la revista Babel. Revista de libros,  publicada en Buenos Aires entre abril de 1988 y marzo de 1991, a partir de un eje singular: la temporalidad que la revista construye y problematiza a partir de pensar su propio presente como un presente en crisis. Como modo de insertarse en el campo intelectual y literario argentino y como estrategia para poder articular las lecturas que le interesa volver centrales, Babel construye una temporalidad entre dos épocas, que supone discutir el fin de la modernidad. Para ver cómo esa temporalidad se construye en la revista, tomaremos dos caminos: por una parte, analizaremos el funcionamiento del discurso sobre lo posmoderno en los primeros dos números de la revista y, por otra parte, intentaremos un recorrido por una sección central de la misma: los “Dossier”.

  7. El Trabajo Fin de Grado Maestro: modalidad online con evaluación presencial

    Directory of Open Access Journals (Sweden)

    Blanca Arteaga Martínez

    2013-01-01

    Full Text Available El plan Bolonia establece que todos los grados deben concluir con la realización de un Trabajo Fin Grado (TFG, cuyo objetivo principal es capacitar al alumno para su futura profesión. La legislación vigente en España permite cierta autonomía para que las Universidades desarrollen esta tarea. En el presente artículo se realiza un análisis de la situación sobre cómo las Universidades españolas ofertan el Grado de Maestro en Educación Infantil y Primaria e imparten el Trabajo Fin de Grado. Se señalan las diferencias entre las Universidades de acuerdo a su titularidad, prestando especial atención a la asignación de los créditos ECTS destinados al TFG. Se toma como ejemplo particular la forma en que está desarrollándose en la Universidad Internacional de la Rioja (UNIR, cuya modalidad de trabajo es online, lo que puede suponer un reto añadido al desarrollo del TFG y a la evaluación de competencias definidas en el grado.

  8. Música de autores costarricenses para guitarra

    OpenAIRE

    Rodríguez-Castillo, Ramonet

    2010-01-01

    Dar a conocer, por medio de ediciones, la música costarricense para guitarra, con el fin de enriquecer el repertorio nacional. Universidad de Costa Rica UCR::Docencia::Artes y Letras::Facultad de Bellas Artes::Escuela de Artes Musicales

  9. Música costarricense para quinteto de vientos

    OpenAIRE

    Pérez-Mora, Yamileth

    2010-01-01

    Dar a conocer, por medio de ediciones, la música costarricense para quinteto de vientos, con el fin de enriquecer el acervo musical Universidad de Costa Rica UCR::Docencia::Artes y Letras::Facultad de Bellas Artes::Escuela de Artes Musicales

  10. Some Exact Solutions of Nonlinear Fin Problem for Steady Heat Transfer in Longitudinal Fin with Different Profiles

    Directory of Open Access Journals (Sweden)

    M. D. Mhlongo

    2014-01-01

    Full Text Available One-dimensional steady-state heat transfer in fins of different profiles is studied. The problem considered satisfies the Dirichlet boundary conditions at one end and the Neumann boundary conditions at the other. The thermal conductivity and heat coefficients are assumed to be temperature dependent, which makes the resulting differential equation highly nonlinear. Classical Lie point symmetry methods are employed, and some reductions are performed. Some invariant solutions are constructed. The effects of thermogeometric fin parameter, the exponent on temperature, and the fin efficiency are studied.

  11. Determination of fin pitches for maximum performance index of L-footed spiral fin-and-tube heat exchangers

    OpenAIRE

    2015-01-01

    In this study, the fin pitches of L-footed spiral finned tube heat exchangers were determined for maximimum performance index. The experiments were done at various fin pitches (fp = 2.4, 3.2, and 4.2 mm) under the range of high Reynolds numbers (5,000–15,000). The test sections had a parallel and counter cross-flow arrangement having the number of tube row of 2. The two working fluids were the ambient air and hot water. The performance indexes (ζ1, ζ2, and ζ3) were used to analyze the experim...

  12. Steady-state and transient heat transfer through fins of complex geometry

    Directory of Open Access Journals (Sweden)

    Taler Dawid

    2014-06-01

    Full Text Available Various methods for steady-state and transient analysis of temperature distribution and efficiency of continuous-plate fins are presented. For a constant heat transfer coefficient over the fin surface, the plate fin can be divided into imaginary rectangular or hexangular fins. At first approximate methods for determining the steady-state fin efficiency like the method of equivalent circular fin and the sector method are discussed. When the fin geometry is complex, thus transient temperature distribution and fin efficiency can be determined using numerical methods. A numerical method for transient analysis of fins with complex geometry is developed. Transient temperature distributions in continuous fins attached to oval tubes is computed using the finite volume - finite element methods. The developed method can be used in the transient analysis of compact heat exchangers to calculate correctly the heat flow rate transferred from the finned tubes to the fluid.

  13. Hydrodynamic properties of fin whale flippers predict maximum rolling performance.

    Science.gov (United States)

    Segre, Paolo S; Cade, David E; Fish, Frank E; Potvin, Jean; Allen, Ann N; Calambokidis, John; Friedlaender, Ari S; Goldbogen, Jeremy A

    2016-11-01

    Maneuverability is one of the most important and least understood aspects of animal locomotion. The hydrofoil-like flippers of cetaceans are thought to function as control surfaces that effect maneuvers, but quantitative tests of this hypothesis have been lacking. Here, we constructed a simple hydrodynamic model to predict the longitudinal-axis roll performance of fin whales, and we tested its predictions against kinematic data recorded by on-board movement sensors from 27 free-swimming fin whales. We found that for a given swimming speed and roll excursion, the roll velocity of fin whales calculated from our field data agrees well with that predicted by our hydrodynamic model. Although fluke and body torsion may further influence performance, our results indicate that lift generated by the flippers is sufficient to drive most of the longitudinal-axis rolls used by fin whales for feeding and maneuvering.

  14. The X-38 V-201 Fin Fold Actuation Mechanism

    Science.gov (United States)

    Lupo, Christian; Robertson, Brandan; Gafka, George

    2004-01-01

    The X-38 Vehicle 201 (V-201) is a space flight prototype lifting body vehicle that was designed to launch to orbit in the Space Shuttle orbiter payload bay. Although the project was cancelled in May 2003, many of the systems were nearly complete. This paper will describe the fin folding actuation mechanism flight subsystems and development units as well as lessons learned in the design, assembly, development testing, and qualification testing. The two vertical tail fins must be stowed (folded inboard) to allow the orbiter payload bay doors to close. The fin folding actuation mechanism is a remotely or extravehicular activity (EVA) actuated single fault tolerant system consisting of seven subsystems capable of repeatedly deploying or stowing the fins.

  15. Computation of boiling water on circular finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Fan, C.C.; Liaw, S.P. [National Taiwan Ocean Univ., Keelung (Taiwan, Province of China). Dept. of Mechanical and Marine Engineering

    1999-04-01

    This study investigates the maximum heat transfer rate and the critical temperature of circular finned tubes in a boiling liquid. The analysis is conducted numerically by solving a two-dimensional heat conduction equation in a steady state. The dependence between heat flux and the temperature at the inner wall of the tube is quantified. Varying the width, height, and pitch of fins, an optimal finned tube with efficient heat transfer rate can be obtained. In the theoretical approach the successive over relaxation (S.O.R.) accompanied with Multi-grid scheme is used. The local heat transfer rates are assumed to follow power-law-type temperature dependence. The initial guess at very high temperatures or so-called a cooling process is also executed in a same way. The results reveal that increasing either the width or the height of a fin increases the total heat transfer rate.

  16. Calculation base of flooded type evaporators with finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Brod, W.; Slipcevic, B.

    1989-03-01

    For the construction of flooded type evaporators with halogen refrigerants, the refrigeration industry is using finned tubes. Equations for thermodynamical calculations of the apparaturs are given, and explained with the aid of a calculation example.

  17. Review of Fin FET Technology and Circuit Design Challenges

    Directory of Open Access Journals (Sweden)

    Bibin Lawrence R,

    2015-12-01

    Full Text Available Considering the difficulties in planar CMOS transistor scaling to secure an acceptable gate to channel control FinFET based multi-gate (MuGFET devices have been proposed as a technology option for replacing the existing technology. The desirability of FinFET that it’s operation principle is same as CMOS process. This permits to lengthening the gate scaling beyond the planar transistor limits, sustaining a steep subthreshold slope, better performance with bias voltage scaling and good matching due to low doping concentration in the channel. There are, still, several challenges and limitations that FinFET technology has to face to be competitive with other technology options: Fin shape, pitch, isolation, doping, crystallographic orientation and stressing as well as device parasitic, performance and patterning approaches will be discussed.

  18. Flexible nanoscale high-performance FinFETs

    KAUST Repository

    Sevilla, Galo T.

    2014-10-28

    With the emergence of the Internet of Things (IoT), flexible high-performance nanoscale electronics are more desired. At the moment, FinFET is the most advanced transistor architecture used in the state-of-the-art microprocessors. Therefore, we show a soft-etch based substrate thinning process to transform silicon-on-insulator (SOI) based nanoscale FinFET into flexible FinFET and then conduct comprehensive electrical characterization under various bending conditions to understand its electrical performance. Our study shows that back-etch based substrate thinning process is gentler than traditional abrasive back-grinding process; it can attain ultraflexibility and the electrical characteristics of the flexible nanoscale FinFET show no performance degradation compared to its rigid bulk counterpart indicating its readiness to be used for flexible high-performance electronics.

  19. Experimental Investigation of Heat Transfer and Pressure Drop Characteristics of H-type Finned Tube Banks

    Directory of Open Access Journals (Sweden)

    Heng Chen

    2014-11-01

    Full Text Available H-type finned tube heat exchanger elements maintain a high capacity for heat transfer, possess superior self-cleaning properties and retain the ability to effect flue gas waste heat recovery in boiler renovations. In this paper, the heat transfer and pressure drop characteristics of H-type finned tube banks are studied via an experimental open high-temperature wind tunnel system. The effects of fin width, fin height, fin pitch and air velocity on fin efficiency, convective heat transfer coefficient, integrated heat transfer capacity and pressure drop are examined. The results indicate that as air velocity, fin height and fin width increase, fin efficiency decreases. Convective heat transfer coefficient is proportional to fin pitch, but inversely proportional to fin height and fin width. Integrated heat transfer capacity is related to fin efficiency, convective heat transfer coefficient and finned ratio. Pressure drop increases with the increase of fin height and fin width. Finally, predictive correlations of fin efficiency, Nusselt number and Euler Number are developed based on the experimental data.

  20. Validation of a Model for Ice Formation around Finned Tubes

    OpenAIRE

    Kamal A. R. Ismai; Fatima A. M. Lino

    2016-01-01

    Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was di...

  1. Wind Fins: Novel Lower-Cost Wind Power System

    Energy Technology Data Exchange (ETDEWEB)

    David C. Morris; Dr. Will D. Swearingen

    2007-10-08

    This project evaluated the technical feasibility of converting energy from the wind with a novel “wind fin” approach. This patent-pending technology has three major components: (1) a mast, (2) a vertical, hinged wind structure or fin, and (3) a power takeoff system. The wing structure responds to the wind with an oscillating motion, generating power. The overall project goal was to determine the basic technical feasibility of the wind fin technology. Specific objectives were the following: (1) to determine the wind energy-conversion performance of the wind fin and the degree to which its performance could be enhanced through basic design improvements; (2) to determine how best to design the wind fin system to survive extreme winds; (3) to determine the cost-effectiveness of the best wind fin designs compared to state-of-the-art wind turbines; and (4) to develop conclusions about the overall technical feasibility of the wind fin system. Project work involved extensive computer modeling, wind-tunnel testing with small models, and testing of bench-scale models in a wind tunnel and outdoors in the wind. This project determined that the wind fin approach is technically feasible and likely to be commercially viable. Project results suggest that this new technology has the potential to harvest wind energy at approximately half the system cost of wind turbines in the 10kW range. Overall, the project demonstrated that the wind fin technology has the potential to increase the economic viability of small wind-power generation. In addition, it has the potential to eliminate lethality to birds and bats, overcome public objections to the aesthetics of wind-power machines, and significantly expand wind-power’s contribution to the national energy supply.

  2. Plates of the dinosaur stegosaurus: forced convection heat loss fins?

    Science.gov (United States)

    Farlow, J O; Thompson, C V; Rosner, D E

    1976-06-11

    It is suggested that the plates along the arched back and tail of Stegosaurus served an important thermoregulatory function as forced convection "fins." Wind tunnel experiments on finned models, internal heat conduction calculations, and direct observations of the morphology and internal structure of stegosaur plates support this hypothesis, demonstrating the comparative effectiveness of the plates as heat dissipaters, controllable through input blood flow rate, temperature, and body orientation (with respect to wind).

  3. Aerodynamic assessment of humpback whale ventral fin shapes

    OpenAIRE

    2011-01-01

    The ventral fins of the humpback whale (Megaptera novaeangliae) include a bulbous leading edge acting as a natural high-lift device. It has been suggested that application of this concept to wing design may yield advantages over traditional shapes (Miklosovic, et al., 2004). During the course of this project, the aerodynamic performance of whale fin models will be compared with conventional wing shapes. Based on the results of the study new wing design paradigms will be developed to improve t...

  4. Numerical Prediction of Pitch Damping Stability Derivatives for Finned Projectiles

    Science.gov (United States)

    2013-11-01

    spinner rocket, but not to a finned projectile. This study presents the first combined application of these methods for finned projectiles in which...and the U.S. Air Force Research Laboratory (AFRL) Aeroballistic Research Facility (ARF) (29) at Eglin Air Force Base in Florida. 2. Theoretical...numerical convergence, the results of which are presented in section4.2.2. 2.2 Steady Lunar Coning Method Murphy (24), Schiff (15, 16), Tobak and Schiff

  5. Blue and fin whale acoustics and ecology off Antarctic Peninsula

    OpenAIRE

    2006-01-01

    Blue (Balaenoptera musculus) and fin whales (B. physalus) in the Southern Ocean were subjects of extensive whaling industry during the twentieth century. Their current population numbers remain low, making population monitoring using traditional visual surveys difficult. Both blue and fin whales produce low frequency, regularly repeated calls and are suitable for acoustic monitoring. Eight, continuously recording acoustic recorders were deployed off the Western Antarctic Peninsula (WAP) betwe...

  6. Venus y el fin del mundo

    Directory of Open Access Journals (Sweden)

    Gonzalo Munévar

    2006-01-01

    Full Text Available Este artículo busca demostrar que los argumentos generales acerca de la exploración científica valen también para las ciencias espaciales. El trabajo se basa en el ejemplo de la exploración de Venus y lo que esta nos dice acerca de nuestro propio planeta. Argumenta que el concepto de la probabilidad de Leslie es incorrecto, como también lo son las dudas sobre la evidencia Venusiana. Así mismo, concluye que no se puede rechazar la importancia que tienen los descubrimientos inesperados que han resultado de la exploración de Venus para ayudarnos a comprender nuestro propio planeta. Y que si van a ser rechazados estos descubrimientos debe ser por razones científicas, no por intuiciones acerca de la probabilidad.

  7. Fin characteristics of aerator devices with lateral deflectors

    Institute of Scientific and Technical Information of China (English)

    WU Jian-hua; LI Dan; MA Fei; QIAN Shang-tuo

    2013-01-01

    The fins will be formed if the lateral deflectors in the side-walls with a bottom aerator device are improperly designed,and the flow regime downstream of the aerator device will be worsened.In this paper,the height and the length of the fins induced by the lateral deflectors are theoretically analyzed along with their influencing factors,and the fin characteristics are experimentally investigated on the basis of the theoretical analysis.It is shown that the intensities of the fins are strongly dependent on the ratio of the lateral cavity length to the bottom cavity length,and other factors,like the working head,the height and the angle of the lateral deflector,the flow Froude number around the aerator device,affect the fins indirectly through the changes of the lateral cavity length.When an aerator device with lateral deflectors is designed,it is crucial to match the above mentioned ratio,and to make the ratio of the two cavity lengths less than 1.0 in order to avoid the generation of the fins.

  8. Experiments with micro-fin tube in single phase

    Energy Technology Data Exchange (ETDEWEB)

    Copetti, J.B.; Macagnan, M.H.; De Souza, D.; Oliveski, R.D.C. [Universidade do Vale do Rio dos Sinos, Sao Leopoldo (Brazil). Department of Mechanical Engineering

    2004-12-01

    This work shows heat transfer and friction characteristics for water single-phase flow in micro-fin tubes. The analysis of thermal and hydraulic behavior from a laminar to a turbulent flow was carried out in an experimental setup with a 9.52 mm diameter micro-fin tube. The tube was wrapped up with an electrical resistance tape to supply a constant heat flux to its surface. Different operational conditions were considered in the heating tests. The inlet and outlet temperatures, differential wall temperatures along the tube, pressure drop and flow rate were measured. The relationships of heat flux and flow rate with heat transfer coefficient and pressure drop were analyzed. Under the same conditions, comparative experiments with an internally smooth tube were conducted. The micro-fin tube provides higher heat transfer performance than the smooth tube (in turbulent flow h{sub micro-fin}/h{sub smooth}=2.9). In spite of the increase in pressure drop ({delta}p{sub micro-fin}/{delta}p{sub smooth}=1.7) the heat transfer results were significantly higher (about 80%). This shows the advantages of this enhanced configuration in thermal performance related to conventional tubes. The smooth tube results were validated by the comparison with the Dittus-Boelter and Gnielinski correlations. For the micro-fin tube an empirical correlation to the heat transfer coefficient adjusted from the set of measured data is proposed. The values obtained are in conformity with experimental results. (author)

  9. Magneto-mechanical actuation model for fin-based locomotion

    CERN Document Server

    Carbajal, Juan Pablo; 10.2495/DN100331

    2011-01-01

    In this paper, we report the results from the analysis of a numerical model used for the design of a magnetic linear actuator with applications to fin-based locomotion. Most of the current robotic fish generate bending motion using rotary motors which implies at least one mechanical conversion of the motion. We seek a solution that directly bends the fin and, at the same time, is able to exploit the magneto-mechanical properties of the fin material. This strong fin-actuator coupling blends the actuator and the body of the robot, allowing cross optimization of the system's elements. We study a simplified model of an elastic element, a spring-mass system representing a flexible fin, subjected to nonlinear forcing, emulating magnetic interaction. The dynamics of the system is studied under unforced and periodic forcing conditions. The analysis is focused on the limit cycles present in the system, which allows the periodic bending of the fin and the generation of thrust. The frequency, maximum amplitude and cente...

  10. Transport in Porous Fins From Laminar to Turbulent Regime

    Science.gov (United States)

    Coletti, Filippo; Muramatsu, Kenshiro; Furciniti, Brian; Elkins, Chris; Eaton, John

    2012-11-01

    Lotus type porous metal has elongated pores of random size and spatial distribution but a common orientation. Sets of so-called lotus fins are obtained by slicing the metal into thin layers and stacking them in the flow path, forcing the fluid to pass through the pores. Lotus fins represent a promising alternative to metal foam heat exchangers, because they offer higher thermal conductivity and lower pressure drop. We have experimentally analyzed the fluid flow and heat transfer in lotus fins to determine their transport properties in a range of flow regimes. The investigated Reynolds numbers based on the pore diameter and inner velocity ranged from 100 to 4000. Three-dimensional mean velocity fields were obtained by magnetic resonance velocimetry performed on magnified replicas of the fins, allowing determination of the mechanical dispersion imposed by the random structure of the fins. Thermal measurements on non-conductive fins provided the global diffusivity coefficient, which accounts for molecular, mechanical and (at high Reynolds number) turbulent diffusion. The latter contribution was isolated and its relevance assessed as a function of the flow regime.

  11. Transcriptional Profiling of Caudal Fin Regeneration in Zebrafish

    Directory of Open Access Journals (Sweden)

    Michael Schebesta

    2006-01-01

    Full Text Available Regeneration of severed limbs in adult animals is restricted to urodele amphibians. Mammals, including humans, have very limited regenerative capabilities and even with proper treatment, only the tips of our digits can grow back. Teleost fish can regenerate amputated fins, the evolutionary ancestors of limbs. To elucidate the principles of limb-fin regeneration, we performed an Affymetrix microarray screen on regenerating caudal fins 12, 24, 48, and 72 h post amputation. Approximately 15,000 zebrafish transcripts were analyzed, identifying 829 transcripts as differentially expressed during regeneration. Of those, 563 were up-regulated and 266 were down-regulated. We constructed a comprehensive database containing expression data, functional assignment, and background information from the literature for each differentially expressed transcript. In order to validate our findings, we employed three approaches: (1 microarray expression analysis of genes previously implicated in fin regeneration, (2 RT-PCR analysis of genes newly identified as differentially expressed during regeneration, and (3 in situ hybridization of the up-regulated genes bambi, dlx5A, and her6. Moreover, we show that Smad 1/5/8 proteins, effector molecules of Bmp signaling, are phosphorylated during fin regeneration. Taken together, we provide a comprehensive database of fin regeneration that will serve as an important tool for understanding the molecular mechanisms of regeneration.

  12. Implications of fin profiles on overall performance and weight reduction of a fin and tube heat exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2017-01-01

    on a cross-flow type fin and tube heat exchanger design for a waste heat recovery application is conducted. The geometric profile of the fin is characterized by a dimensionless design variable named aspect ratio which is parametrically varied to obtain different profiles. Two cases, case-I, and case......Fin and tube heat exchangers are being used in several industrial applications by means of novel design and optimized performance. Improvements in geometric design may deliver energy efficient and cost-effective heat exchanger performance with reduced weight. In this paper, a systematic study...... design. Results show that the overall performance improves by approximately 6.76% and 17.33% with a reduction in net unit weight by approximately 27.58% and 6.82% on changing the aspect ratio from 1.0 to 0.1 in case-I and case-II, respectively. In addition, feasible fin profile for a waste heat recovery...

  13. Some exact solutions of nonlinear fin problem for steady heat transfer in longitudinal fin with different profiles

    CSIR Research Space (South Africa)

    Mhlongo, MD

    2014-05-01

    Full Text Available Solutions of Nonlinear Fin Problem for Steady Heat Transfer in Longitudinal Fin with Different Profiles M. D. Mhlongo1 and R. J. Moitsheki2 1 Defence, Peace, Safety and Security, Landward Sciences, Council for Scientific and Industrial Research, P.O. Box 395... efficiency are studied. 1. Introduction Heat transfer through extended surfaces has been studied quite extensively [1], perhaps because of its frequent applica- tions in engineering. Through the process of mathematical modeling, heat transfer problems...

  14. The performance of a new gas to gas heat exchanger with strip fin

    NARCIS (Netherlands)

    Wang, J.; Hirs, G.G.; Rollmann, P.

    1999-01-01

    A compact gas to gas heat exchanger needs large heat transfer areas on both fluid sides. This can be realised by adding secondary surfaces. The secondary surfaces are plate fin, strip fin, and louvered fin, etc. The fins extend the heat transfer surfaces and promote turbulence. This paper presents

  15. Fish larvae exploit edge vortices along their dorsal and ventral fin folds to propel themselves

    NARCIS (Netherlands)

    Li, G.; Müller, U.K.; Leeuwen, van J.L.; Liu, Hao

    2016-01-01

    Larvae of bony fish swim in the intermediate Reynolds number (Re) regime,
    using body- and caudal-fin undulation to propel themselves. They share a
    median fin fold that transforms into separate median fins as they grow into
    juveniles. The fin fold was suggested to be an adaption for locom

  16. Cytoskeletal dynamics of the teleostean fin ray during fin epimorphic regeneration.

    Science.gov (United States)

    Santos-Ruiz, Leonor; Santamaría, Jesús Alberto; Becerra, José

    2005-04-01

    Teleost fishes can regenerate their fins by epimorphic regeneration, a process that involves the transition of the formerly quiescent tissues of the stump to an active, growing state. This involves dynamic modifications of cell phenotype and behavior that must rely on alterations of the cytoskeleton. We have studied the spatial and temporal distribution of three main components of the cytoskeleton (actin, keratin and vimentin) in the regenerating fin, in order to establish putative relationships between cell cytoskeleton and cell behavior. According to our results, the massive rearrangement undergone by the epidermis right after injury, which takes place by cell migration, correlates with a transient down-regulation of keratin and a strong up-regulation of actin in the epidermal cells. During the subsequent epidermal growth, based on cell proliferation, keratin normal pattern is recovered while actin is down-regulated, although not to normal (quiescent) levels. The epidermal basal layer in contact with the blastema displays a particular cytoskeletal profile, different to that of the rest of the epidermal cells, which reflects its special features. In the connective tissue compartment, somatic cells do not contain vimentin, but keratin, as intermediate filament. Proliferative and migrative activation of these cells after injury correlates with actin up-regulation. Although this initial activation does not involve keratin down-regulation, blastemal cells were later observed to lack keratin, suggesting that such cytoskeletal modification might be needed for connective tissue cells to dedifferentiate and form the blastema. Cell differentiation in the newly formed, regenerated ray is accompanied by actin down-regulation and keratin up-regulation.

  17. Experimental Study on Condensation of Pure Refrigerants in Horizontal Micro-fin Tubes

    Science.gov (United States)

    Yonemoto, Ryuichiro; Koyama, Shigeru

    This paper presents the heat transfer and pressure drop correlations for condensation in micro-fin tubes. Experimental data for eleven micro-fin tubes with different fin dimensions were used, and the refrigerants tested were R22, R123 and R134a. The predicted results using new correlations show good agreement with experimental results within an absolute deviation of ±30%. Experimental results for the micro-fin tubes were also compared with previous correlations for micro-fin Tubes.

  18. Defective Fin Regeneration in Medaka Fish (Oryzias latipes) with Hypothyroidism full access

    OpenAIRE

    Sekimizu, Koshin; Tagawa, Masatomo; Takeda, Hiroyuki

    2007-01-01

    Wild-type medaka are known to have remarkable capabilities of fin, or epimorphic, regeneration. However, a hypothyroid mutant, kamaitachi (kmi), frequently suffers from injury in fins, suggesting an important role of thyroid hormone in fin regeneration. This led us to examine the relationship between thyroid hormone and fin regeneration using medaka as a model. For this, we first set up a medaka experimental system in which the rate of regeneration was statistically analyzed after caudal fin ...

  19. Caracterização das florestas ribeirinhas do rio Formoso e Parque Nacional da Serra da Bodoquena/MS, quanto as espécies ocorrentes e histórico de perturbação, para fins de restauração

    OpenAIRE

    Vivian Ribeiro Baptista-Maria

    2007-01-01

    Reconstruir um ecossistema florestal ribeirinho a partir de uma abordagem cientifica, implica em conhecer a diversidade florística, a complexidade dos fenômenos que se desenvolvem nestas formações, compreender os processos que levam a estruturação e manutenção destes ecossistemas no tempo e utilizar estas informações para a elaboração, implantação e condução de projetos de restauração. Neste sentido, este trabalho teve por objetivo (i) identificar e caracterizar a composição florística das fl...

  20. RECONHECENDO O VALOR DO COOPERATIVISMO SOB A ÓTICA DA CADEIA MEIOS-FINS

    Directory of Open Access Journals (Sweden)

    Agda Silva Prado

    2015-01-01

    Full Text Available As instituições cooperativistas são importantes promotoras do agronegócio brasileiro, pois através delas, pequenos, médios e grandes agricultores se unem para estabelecerem melhores condições de compra e venda de produtos. Entretanto, faz-se necessário averiguar mercadologicamente qual o valor das cooperativas para os cooperados, como forma de mantê-los unidos e proporcionar desenvolvimento para o setor. Assim, este trabalho tem como objetivo identificar a estrutura cognitiva de valor percebida pelos cooperados de uma cooperativa agropecuária no Sul de Minas Gerais. A pesquisa parte de uma abordagem qualitativa através da teoria de cadeia de meios-fins, utilizando o método de escalonamento laddering e a análise de conteúdo em 25 entrevistas em profundidade. Como resultados, identificou-se que os valores: tranquilidade, felicidade, realização, melhor qualidade de vida e sentimento de pertença são as principais motivações para a participação dos cooperados na cooperativa. Esse estudo contribui no desenvolvimento de pesquisas ligadas ao agronegócio, na compreensão de valores capazes de estimular o fortalecimento de ações cooperativistas e estratégias de marketing.

  1. Sobre los orígenes de la doctrina de la frustración del fin del contrato: comentario al fallo Krell v. Henry

    Directory of Open Access Journals (Sweden)

    Manin, María S.

    2012-12-01

    Full Text Available En materia de contratos no es pacifica la aceptación del instituto de la frustración del fin del contrato. El fallo Krell v. Henry es para la doctrina causalista el primer caso en el que se aceptó la existencia de la causa-fin como elemento de este. Empero, si leemos detenidamente el fallo de la Court of Appeal of England and Wales (Civil Division encontraremos que la doctrina de este se identifica más con la de los neocausalistas que con la de los causalistas . Este trabajo se propone pasar revista del fallo Krell v. Henry y realizar un análisis crítico del instituto de la frustración del fin del contrato y su posible aplicación en nuestro Derecho, teniendo en cuenta los aportes de las tres escuelas teóricas que lo estudian: anticausalistas, causalistas y neocausalistas.

  2. FinFET Architecture Analysis and Fabrication Mechanism

    Directory of Open Access Journals (Sweden)

    Sarman K Hadia

    2011-09-01

    Full Text Available In view of difficulties of the planar MOSFET technology to get the acceptable gate control over the channel FinFET technology based on multiple gate devices is better technology option for further shrinking the size of the planar MOSFET [1]. For double gate SOI- MOSFET the gates control the channel created between source and drain terminal effectively. So the several short channel effects like DIBL, subthreshold swing, gate leakage current etc. without increasing the carrier concentration into the channel. This paper mainly deals with detail description about the DG MOSFET structure and its particular type named as FinFET technology and its fabrication mechanism is also described. Below the 50nm technology FinFET has better controlling over the several short channel effects. In section one the introduction is given, section two describe the Evaluation from previous technology, section three describe the DG MOSFET structure and its type, section four describe the FinFET technology, section five describe the fabrication mechanism of the FinFET technology and finally conclusions given in section six.

  3. Fin Buffeting Features of an Early F-22 Model

    Science.gov (United States)

    Moses, Robert W.; Huttsell, Lawrence

    2000-01-01

    Fin buffeting is an aeroelastic phenomenon encountered by high performance aircraft, especially those with twin vertical tails that must operate at high angles of attack. This buffeting is a concern from fatigue and inspection points of view. To date, the buffet (unsteady pressures) and buffeting (structural response) characteristics of the F-15 and F/A-18 fins have been studied extensively using flow visualization, flow velocity measurements, pressure transducers, and response gages. By means of windtunnel and flight tests of the F-15 and F/A-18, this phenomenon is well studied to the point that buffet loads can be estimated and fatigue life can he increased by structural enhancements to these airframes. However, prior to the present research, data was not available outside the F-22 program regarding fin buffeting on the F-22 configuration. During a test in the Langley Transonic Dynamics Tunnel, flow visualization and unsteady fin surface pressures were recorded for a 13.3%-scale F-22 model at high angles of attack for the purpose of comparing with results available for similar aircraft configurations. Details of this test and fin buffeting are presented herein.

  4. Research on the Pin Fin Efficiency and Structure

    Directory of Open Access Journals (Sweden)

    Fan Bailin

    2013-06-01

    Full Text Available The performance of pin fin heat sink can be to measure through the temperature field. The temperature field and efficiency of the Pin Fin were analyzed, Pin fin efficiency curve was drowned also the distribution of the temperature field along the length of the pin fin curve was drawn. Thermal resistance was composed by thermal resistance of Aluminum substrate、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. The change rule was studied through the calculation on Aluminum plate thermal resistance、 thermal resistance of convective heat transfer and the thermal resistance of the cooling liquid. Its change regularity was simulated by toolbox In the MATLAB, and it was found that thermal resistance of convective heat transfer effect on the efficiency was most obvious in a certain amount of the heat and flow for thermal resistance of the Pin-fin radiator under the premise. The structural parameters of radiator were related to the size of thermal resistance.

  5. Vortical structures in the wake of an undulating fin

    Science.gov (United States)

    Dewey, Peter A.; Carriou, Antoine; Smits, Alexander J.

    2010-11-01

    Batoid fish such as the manta ray propel themselves through the water by producing a traveling wave motion along the chord of their pectoral fin. Such a motion produces thrust through the development of an unsteady vortex street that results in a jet-like average flow. Digital particle image velocimetry (DPIV) is used to characterize the vortical patterns and structures developed in the wake of a manta ray-like fin. A DC servo motor powers a gear train to produce the traveling wave motion; whose frequency and wave length can be varied. The amplitude of the traveling wave motion linearly increases along the span of the fin. Wake morphologies for a wide spectrum of oscillation frequencies and traveling wave wavelengths are identified. A bifurcation from a 2S wake structure to a 2P wake structure is observed as the traveling wave wavelength is decreased, which corresponds to a decrease in efficiency as reported by Clark and Smits (2006). Alteration of the oscillation frequency, and thus Strouhal number, affects vortex interaction and is found to significantly modify the resulting velocity profiles in the wake of the fin. Notably, increasing the Strouhal number beyond optimal conditions, reported by Clark and Smits, corresponds to a reduction in the extent that the jet-like average flow is observed downstream of the fin.

  6. Pool boiling on rectangular fins with tunnel-pore structure

    Directory of Open Access Journals (Sweden)

    Pastuszko A.

    2013-04-01

    Full Text Available Complex experimental investigations were conducted in the area of pool boiling heat transfer on extended surfaces with internal tunnels limited by perforated foil. The experiments were carried out for water and R-123 at atmospheric pressure. The tunnel surfaces were fabricated from 0.05 – 0.1 mm thick perforated copper foil (pore diameters: 0.3, 0.4, 0.5 mm sintered with mini-fins formed by 5 and 10 mm high rectangular fins and horizontal inter-fin surface. The effect of the main fin height, pore diameters and tunnel pitch on nucleate pool boiling was examined. Substantial enhancement of heat transfer coefficient was observed for the investigated surfaces. The highest increase in the heat transfer coefficient was obtained for the 10 mm high fins – about 50kW/m2K for water and 15 kW/m2K for R-123. The investigated surfaces showed boiling heat transfer coefficients similar to those of existing tunnel-pore structures.

  7. Optimization of Internal Cooling Fins for Metal Hydride Reactors

    Directory of Open Access Journals (Sweden)

    Vamsi Krishna Kukkapalli

    2016-06-01

    Full Text Available Metal hydride alloys are considered as a promising alternative to conventional hydrogen storage cylinders and mechanical hydrogen compressors. Compared to storing in a classic gas tank, metal hydride alloys can store hydrogen at nearly room pressure and use less volume to store the same amount of hydrogen. However, this hydrogen storage method necessitates an effective way to reject the heat released from the exothermic hydriding reaction. In this paper, a finned conductive insert is adopted to improve the heat transfer in the cylindrical reactor. The fins collect the heat that is volumetrically generated in LaNi5 metal hydride alloys and deliver it to the channel located in the center, through which a refrigerant flows. A multiple-physics modeling is performed to analyze the transient heat and mass transfer during the hydrogen absorption process. Fin design is made to identify the optimum shape of the finned insert for the best heat rejection. For the shape optimization, use of a predefined transient heat generation function is proposed. Simulations show that there exists an optimal length for the fin geometry.

  8. Análisis para la modelación y optimización geométrica de un reactor tipo tornillo sin-fin empleando el método de grafos dicromáticos//Analysis for geometric modeling and optimization of a worm type reactor using the method of dichromatic graph

    Directory of Open Access Journals (Sweden)

    Armando Díaz-Concepción

    2015-09-01

    Full Text Available En el presente trabajo se realiza la modelación, simulación y optimización de un reactor utilizado en las plantas para la obtención de un alimento animal, sobre la base de la predigestión del bagacillo de caña y el hidróxido de calcio en presencia de vapor denominado PREDICAL utilizando grafos dicromáticos. Se obtuvo el modelo matemático para el diseño del reactor, donde se vinculan las variables geométricas y tecnológicas. El modelo formulado permitió la optimización de la variable costo a partir de minimizar la variable geométrica diámetro exterior del reactor. Palabras claves: modelación reactor tipo tornillo sinfin, grafos dicromáticos, modelo matemático________________________________________________________________________________AbstractThe present work performs modeling, simulation and optimization of a reactor used in plants for the obtencion of animal feed. It's made on the basis of pre-digestion of cane bagasse and calcium hydroxide in the presence of steam called PREDICAL and using dichromatic graphs. It was achieved the mathematical model for the design of the reactor, where are linked geometric and technological variables. The model developed allowed cost optimization based on minimize the geometric variable outside diameter of the reactor. Key words: worm type reactor modeling, dichromatic graphs, mathematical model.

  9. Film condensation of HCFC-123 on staggered bundles of horizontal finned tubes. Effect of fin geometry; Suihei fintsukikan no chidori kanbun ni okeru HCFC-123 no gyoshuku. Fin keijo no eikyo

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H.; Takamatsu, H.; Takada, N. [Kyushu University, Fukuoka (Japan). Institute of Advanced Material Study; Makishi, O. [Kyushu University, Fukuoka (Japan); Sejimo, H. [NKK Corp., Tokyo (Japan)

    1995-03-25

    Experiments were conducted to obtain row-by-row heat transfer data during condensation of downward flowing HCFC-123 vapor in staggered bundles of horizontal two-dimensional fin tubes. Two conventional low fin tubes and two finned tubes with fin shapes close to that of a new high-performance fin proposed by Zhu and Honda were tested. The latter tubes had fin dimensions that were optimized by theoretical analysis. The heat transfer characteristics were compared with previous results for in-line bundles of the same test tubes and with theoretical predictions for stagnant vapor. The decrease in heat transfer due to condensate inundation was less significant for the staggered tube bundle. The highest heat transfer coefficient was provided by the staggered bundle of one of the new finned tubes. The theoretical predictions compared well with experimental data at a low vapor velocity and a low to medium condensate inundation rate. 15 refs., 10 figs., 2 tabs.

  10. Development of colburn ` j' factor and fanning friction factor ` f' correlations for compact heat exchanger plain fins by using CFD

    Science.gov (United States)

    Bala Sundar Rao, R.; Ranganath, G.; Ranganayakulu, C.

    2013-07-01

    A numerical model has been developed for plain fin of plate fin heat exchanger. Plain fin performance has been analyzed with the help of CFD by changing the various parameters of the fin, Colburn ` j' and fanning friction ` f' factors are calculated. These values compared with the standard values. The correlations have been developed between Reynolds number Re, fin height h, fin thickness t, fin spacing s, Colburn factor ` j' and friction factor ` f'.

  11. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    Directory of Open Access Journals (Sweden)

    Stolecki M.

    2015-09-01

    Full Text Available This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301 austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614, and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, one performed metallographic examinations, hardness measurements and a technological attempt to rupture the fin. Analysis of the results proved that the laser-welded finned tubes were performed correctly and that the welded joints had shown no imperfections.

  12. Heat transfer of smooth and finned tubes in A CFBC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, B.H. [Korea Electric Power Research Institute, Taejeon (Korea); Cho, H.H. [Yonsei University, Seoul (Korea)

    2000-11-01

    The objective of present work is to investigate experimentally the characteristics of heat transfer. A fluidized bed combustion has advantages of pollution control, fuel flexibility and excellent heat transfer. The present study investigates fundamental phenomena of bed-to-surface heat transfer in high temperature fluidized beds to improve design of immersed tube surface. The tested operating variables are bed temperature, superficial velocity, mean size of bed material, and the rake angle of fin. Generally, heat transfer rates between the fluidized bed and immersed finned-tube are much higher than those of a smooth tube. A life time of finned-tube is generally longer than that of smooth tube. (author). 4 figs.

  13. A thermal study of pipes with outer transverse fins

    Directory of Open Access Journals (Sweden)

    S. Gil

    2016-10-01

    Full Text Available This paper provides results of thermal investigations on pipes with outer transverse fins produced by placing a strip, being a form of helical spring which functions as a radiator, on the basis pipe. The investigations were carried out at the facility that enables measurements with respect to both natural and forced convection. Performance of the investigated pipes was assessed in relation to a non-finned pipe and a pipe welded with the use of Metal Active Gas (MAG technology. The experiments have shown that the finned pipe welding technology does not markedly affect their thermal efficiency, which has been confirmed by performed model calculations, while the welding technology has a crucial impact on their operating performance.

  14. Development and evolution of the muscles of the pelvic fin.

    Directory of Open Access Journals (Sweden)

    Nicholas J Cole

    2011-10-01

    Full Text Available Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition.

  15. Boiling visualization on vertical fins with tunnel-pore structures

    Directory of Open Access Journals (Sweden)

    Kaniowski Robert

    2012-04-01

    Full Text Available The paper presents experimental studies of nucleate boiling heat transfer from a system of connected horizontal and vertical subsurface tunnels. The experiments were carried out for water at atmospheric pressure. The tunnel external covers were manufactured out of perforated copper foil (holes diameter 0.3 mm, sintered with the mini-fins, formed on the vertical side of the 10 mm high rectangular fins and horizontal inter-fin surface. The image acquisition speed was 493 fps (at resolution 400 × 300 pixels with Photonfocus PHOT MV-D1024-160-CL camera. Visualization investigations aimed to identify nucleation sites and flow patterns and to determine the bubble departure diameter and frequency at various superheats for vertical tunnels. At low superheat vapor bubbles are generated nearly exclusively by the vertical tunnel. At medium values of superheat, pores of the horizontal tunnel activate.

  16. Wake Vortex Structure Characteristics of a Flexible Oscillating Fin

    Institute of Scientific and Technical Information of China (English)

    Zhi-dong Wang; Pei Chen; Xiao-qing Zhang

    2008-01-01

    We compute the wake of a two-dimensional and three-dimensional flexible fin in an unsteady flow field with heaving and pitching motions using FLUENT. Deflexion mode is used for a non-uniform cantilever beam with non-uniformly distributed load. The effect of chordwise deflexion length on the characteristics of propulsion is discussed for two-dimensional flexible fin.The thrust coefficient decreases, propulsive efficiency increases and the intensity of turbulence attenuates gradually as the deflexion length increases. For a three-dimensional flexible fin, the intensity of the vortex in the plane of symmetry is higher than that in the plane at 3/4 span length of the caudal fro. But the propulsive performance achieved is not what we expected with the given deflexion mode.

  17. Efficiency of the unit cell in rectangular finned tube arrangements

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, Luca; Dall' Olio, Roberto; Spiga, Marco [Bologna Univ., DIENCA, Bologna (Italy)

    1999-11-01

    This paper is aimed at presenting an investigation concerning the efficiency of the single unit in finned air-cooled heat exchangers with staggered and in-line bundles of rectangular ducts, where a hot process fluid flows inside extended-surface tubes and atmospheric air is circulated outside, over the extended surface. The differential energy equation is numerically solved by a finite difference technique, in order to determine the spatial temperature profiles, then the fin efficiency and the augmentation factor are calculated by a simple numerical integration. The results show that the temperature distribution and the fin performance depend on four dimensionless parameters (m,{beta},p{sub x},p{sub y}), the first accounting for the heat transfer condition, the other ones accounting for the geometry of the extended surface (tube aspect ratio and pitches). Several tables are presented, allowing the efficiency of the extended surface to be deduced as a function of the thermal and geometric parameters. (Author)

  18. Development and Evolution of the Muscles of the Pelvic Fin

    Science.gov (United States)

    Cole, Nicholas J.; Hall, Thomas E.; Don, Emily K.; Berger, Silke; Boisvert, Catherine A.; Neyt, Christine; Ericsson, Rolf; Joss, Jean; Gurevich, David B.; Currie, Peter D.

    2011-01-01

    Locomotor strategies in terrestrial tetrapods have evolved from the utilisation of sinusoidal contractions of axial musculature, evident in ancestral fish species, to the reliance on powerful and complex limb muscles to provide propulsive force. Within tetrapods, a hindlimb-dominant locomotor strategy predominates, and its evolution is considered critical for the evident success of the tetrapod transition onto land. Here, we determine the developmental mechanisms of pelvic fin muscle formation in living fish species at critical points within the vertebrate phylogeny and reveal a stepwise modification from a primitive to a more derived mode of pelvic fin muscle formation. A distinct process generates pelvic fin muscle in bony fishes that incorporates both primitive and derived characteristics of vertebrate appendicular muscle formation. We propose that the adoption of the fully derived mode of hindlimb muscle formation from this bimodal character state is an evolutionary innovation that was critical to the success of the tetrapod transition. PMID:21990962

  19. Pilarização de esmectita brasileira para fins catalíticos. Emprego de argila pilarizada na alquilação de benzeno com 1-dodeceno Pillarization of Brazilian smectite for the catalytic of purpose. Use of pillared clay in the alkylation of benzene with 1-dodecene

    Directory of Open Access Journals (Sweden)

    Sidnei Quezada M. Leite

    2000-04-01

    Full Text Available Al-pillared clay was prepared with a Brazilian bentonite from the Campina Grande region (Paraíba, BRAZIL. It was intercalated at 298 K, during 48 hours, with a solution containing [Al3+] = 0.10 mol/L and molar ratio OH/Al = 2.0 prepared at 333 K, and was calcined at 773K. The catalytic activity was evaluated by alkylation of benzene with 1-dodecene. The characterization methods were: X-ray fluorescence and diffraction analysis; 27Al, 29Si and 23Na MAS NMR and textural analysis by N2 adsorption. The thermal stability of the natural clay was improved by the pillaring procedure, as well as the catalytic activity. The intercalated clay presented the highest initial rate of reaction among the systems tested.

  20. Effect of Fin-Collar Shape at Contact Area between Tube and Fin on Heat Exchanger Performance

    Science.gov (United States)

    Matsuo, Yoshimi; Tsubaki, Koutaro; Miyara, Akio

    In this study, numerical simulation of a cross fin-tube heat exchanger was conducted to investigate the effects of fin-collar shape on the heat transfer performance and pressure drop. During the making process, two adjacent fin-collars and a tube form a triangular space and the end of fin collar protrude to air side. To investigate these effects on the heat exchanger performance, the form ratio was defined to make an indicator of the triangular space size. Furthermore, the simulation of the models with and without protruded end was conducted. The results indicated that the increase of the form ratio results in the decrease in the heat transfer rate. On the other hand, it contributed to a relatively small increase in the heat transfer coefficient on the air side. A high heat transfer coefficient on the air side was obtained by the protruded fin-collar end. However, the pressure drop was not much different between the models with and without the protruded end. The ratio of the thermal contact resistance to the air side thermal resistance was about 1:5 for the form ratio of 20% to 40%.

  1. Atom-probe for FinFET dopant characterization.

    Science.gov (United States)

    Kambham, A K; Mody, J; Gilbert, M; Koelling, S; Vandervorst, W

    2011-05-01

    With the continuous shrinking of transistors and advent of new transistor architectures to keep in pace with Moore's law and ITRS goals, there is a rising interest in multigate 3D-devices like FinFETs where the channel is surrounded by gates on multiple surfaces. The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions of the device. As a result there is a need for new metrology approach/technique to characterize quantitatively the dopant distribution in these devices with nanometer precision in 3D. In recent years, atom probe tomography (APT) has shown its ability to analyze semiconductor and thin insulator materials effectively with sub-nm resolution in 3D. In this paper we will discuss the methodology used to study FinFET-based structures using APT. Whereas challenges and solutions for sample preparation linked to the limited fin dimensions already have been reported before, we report here an approach to prepare fin structures for APT, which based on their processing history (trenches filled with Si) are in principle invisible in FIB and SEM. Hence alternative solutions in locating and positioning them on the APT-tip are presented. We also report on the use of the atom probe results on FinFETs to understand the role of different dopant implantation angles (10° and 45°) when attempting conformal doping of FinFETs and provide a quantitative comparison with alternative approaches such as 1D secondary ion mass spectrometry (SIMS) and theoretical model values.

  2. Narraciones españolas del fin del mundo. II. Las novelas religiosas

    Directory of Open Access Journals (Sweden)

    Jaureguízar, Agustín

    2011-06-01

    Full Text Available There are three novels published between 1920 and 1935 which I have chosen as a token of spanish classical narrative. Their authors judge a fading Mankind on its evilness, reaching different outcomes: in one, the righteous are saved while the sinners are banished to Hell, at so great a speed that they are still alive on arrival; in another, only a handful of the chosen, who get to another planet, survives, and in the last, well, Mankind is extinguished and God creates a new Man and a new Woman in a Paradise where He’s uprooted the tempting Tree of Knowledge.

    Como muestra de las narraciones clásicas españolas del fin de los tiempos se han escogido tres novelas publicadas entre 1920 y 1935. Sus autores juzgan por su maldad a una Humanidad que desaparece, llegando a resultados distintos: en una los justos se salvan mientras los pecadores son arrojados a los infiernos a tan gran velocidad que llegan vivos a ellos; en otra sólo sobrevive un puñado de elegidos, que alcanza otro planeta, y en la tercera, en fin, la Humanidad se extingue por completo y Dios crea otro Hombre y otra Mujer en un Paraíso del que ha arrancado de raíz el árbol tentador del Bien y del Mal.

  3. Investigation of Heat Transfer Through Fins Using Fem

    Directory of Open Access Journals (Sweden)

    Mr. H.N. Gandate

    2014-10-01

    Full Text Available Analysis of heat distribution, thermal stresses and strain for engine cylinder and fins are discussed in this paper. The cylinder and fins being analysed using finite (FE software ANSYS AND by FE (simple model. When a cylinder is subjected to certain pressure and temperature thermal distribution and thermal stresses analysis of cylinder is necessary to avoid the failure during working condition. In this work the temperature distribution and thermal stresses are evaluated by considering only temperature effect, temperature and gas pressure effect and also evaluate the same by considering the effect of cylinder head.

  4. Atom-probe for FinFET dopant characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kambham, A.K., E-mail: kambham@imec.be [K.U.Leuven, Instituut voor Kern-en Stralings fysika, Celestijnenlaan 200D, B-3001, Leuven (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium); Mody, J.; Gilbert, M.; Koelling, S.; Vandervorst, W. [K.U.Leuven, Instituut voor Kern-en Stralings fysika, Celestijnenlaan 200D, B-3001, Leuven (Belgium); IMEC, Kapeldreef 75, B-3001 Leuven (Belgium)

    2011-05-15

    With the continuous shrinking of transistors and advent of new transistor architectures to keep in pace with Moore's law and ITRS goals, there is a rising interest in multigate 3D-devices like FinFETs where the channel is surrounded by gates on multiple surfaces. The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions of the device. As a result there is a need for new metrology approach/technique to characterize quantitatively the dopant distribution in these devices with nanometer precision in 3D. In recent years, atom probe tomography (APT) has shown its ability to analyze semiconductor and thin insulator materials effectively with sub-nm resolution in 3D. In this paper we will discuss the methodology used to study FinFET-based structures using APT. Whereas challenges and solutions for sample preparation linked to the limited fin dimensions already have been reported before, we report here an approach to prepare fin structures for APT, which based on their processing history (trenches filled with Si) are in principle invisible in FIB and SEM. Hence alternative solutions in locating and positioning them on the APT-tip are presented. We also report on the use of the atom probe results on FinFETs to understand the role of different dopant implantation angles (10{sup o} and 45{sup o}) when attempting conformal doping of FinFETs and provide a quantitative comparison with alternative approaches such as 1D secondary ion mass spectrometry (SIMS) and theoretical model values. -- Research highlights: {yields} This paper provides the information on how to characterize the FinFET devices using atom probe tomography (APT). {yields} Importance of this work is to assess the performance of these devices at different processing conditions by extracting the compositional profiles. {yields} The performance of these devices depends on the dimensions and the spatial distribution of dopants in source/drain regions

  5. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured......The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...

  6. Finned tubes for heat exchangers: Characterization and performance simulation

    Energy Technology Data Exchange (ETDEWEB)

    Armand, J.-L.; Molle, N. (Centre Tecnique des Industries Aerauliques et Thermiques (CETIAT), 75 Paris (France))

    1992-06-01

    Relevant to air conditioning applications, the state-of-the-art of finned tube heat exchanger design is reviewed. The review covers the key design, performance and operation characteristics, as well as, principal heat transfer correlations for exchangers adopting 'dry' (without condensation) and 'wet' operation. External side heat transfer and pressure drop calculation methods are established for the characterization of external surfaces. For internal surfaces, correlations are given for two-phase flow and pressure drop. Reference is made to the NTU and CANUT simulation codes for the determination of optimum finned tube geometries for standard and particular operating conditions.

  7. Validation of a Model for Ice Formation around Finned Tubes

    Directory of Open Access Journals (Sweden)

    Kamal A. R. Ismai

    2016-09-01

    Full Text Available Phase change materials although attaractive option for thermal storage applications its main drawback is the slow thermal response during charging and discharging processes due to their low thermal conductivity. The present study validates a model developed by the authors some years ago on radial fins as a method to meliorate the thermal performance of PCM in horizontal storage system. The developed model for the radial finned tube is based on pure conduction, the enthalpy approach and was discretized by the finite difference method. Experiments were realized specifically to validate the model and its numerical predictions.

  8. Integral finned heater and cooler for stirling engines

    Science.gov (United States)

    Corey, John A.

    1984-01-01

    A piston and cylinder for a Stirling engine and the like having top and bottom meshing or nesting finned conical surfaces to provide large surface areas in close proximity to the working gas for good thermal (addition and subtraction of heat) exchange to the working gas and elimination of the usual heater and cooler dead volume. The piston fins at the hot end of the cylinder are perforated to permit the gas to pass into the piston interior and through a regenerator contained therein.

  9. Net Shape Fins for Compact Heat Exchanger Produced by Cold Spray

    Science.gov (United States)

    Cormier, Yannick; Dupuis, Philippe; Jodoin, Bertrand; Corbeil, Antoine

    2013-10-01

    This work explores the manufacturability of pyramidal fin arrays produced using the cold spray process. Near-net shaped pyramidal fin arrays of various sizes and fin densities were manufactured using masks made of commercially available steel wire mesh. The feedstock powders used to produce the fins are characterized using scanning electron microscopy. Obstruction of the masks was investigated. The standoff distances between the substrate, mesh, and nozzle were empirically determined. Fin array characterization was performed using digital microscopy. The fin arrays' heat transfer performance was assessed experimentally for a range of Reynolds number relevant to the application sought. The fins produced using the cold spray process outperform traditional straight (rectangular) fins at the same fin density and it is hypothesized that this is due to increased fluid mixing and turbulence.

  10. Formation mechanism of external finned tubes by extrusion-plough method

    Institute of Scientific and Technical Information of China (English)

    TANG Yong; LU Long-sheng; PAN Min-qing; LIU Xiao-kang; LIU Xiao-qing

    2006-01-01

    The formation mechanism of bulge on the work's surface during the extrusion process was analyzed. The bulge's size and the reasons for abscission were studied. The results show that the abscission of bulge from works is resulted from the integrated actions of pressure and friction between the plough tool and works. During the extrusion-plough process, it is noticed that four kinds of fins are appeared, which are gestation fin, multi-dimensional fin, tumor and overlap fin, when using different machining parameters. And multi-dimensional fin which has high heat transmission efficiency is a kind of complicated fin with cockscomb-like 3D substructure fin on the tip of 3D macrostructure fin. Based on the studies of those four kinds of fins, the conditions of their formation are concluded, as well as the formation mechanism is obtained.

  11. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    DEFF Research Database (Denmark)

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer;

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

  12. DSA patterning options for FinFET formation at 7nm node

    Science.gov (United States)

    Liu, Chi-Chun C.; Franke, Elliott; Lie, Fee Li; Sieg, Stuart; Tsai, Hsinyu; Lai, Kafai; Truong, Hoa; Farrell, Richard; Somervell, Mark; Sanders, Daniel; Felix, Nelson; Guillorn, Michael; Burns, Sean; Hetzer, David; Ko, Akiteru; Arnold, John; Colburn, Matthew

    2016-03-01

    Several 27nm-pitch directed self-assembly (DSA) processes targeting fin formation for FinFET device fabrication are studied in a 300mm pilot line environment, including chemoepitaxy for a conventional Fin arrays, graphoepitaxy for a customization approach and a hybrid approach for self-aligned Fin cut. The trade-off between each DSA flow is discussed in terms of placement error, Fin CD/profile uniformity, and restricted design. Challenges in pattern transfer are observed and process optimization are discussed. Finally, silicon Fins with 100nm depth and on-target CD using different DSA options with either lithographic or self-aligned customization approach are demonstrated.

  13. Necropsy report of a fin whale (Balaenoptera physalus) stranded in Denmark in 2010

    DEFF Research Database (Denmark)

    Alstrup, Aage K. O.; Hedayat, Abdi; Jensen, Trine Hammer

    2013-01-01

    There is little detailed information on stranded fin whales (Balaenoptera physalus) in the scientific literature (Notarbartolo di Sciara et al., 2003). In Denmark, at least eight fin whales stranded between the years 1603 and 1958 (Kinze, 1995). On 16 June 2010, a live subadult or adult male fin...... whale stranded in the Bay of Vejle (55º 69' N, 9º 58' E), Denmark. Despite several attempts, it was not possible to rescue the fin whale, which was only partially exposed by the water. The fin whale succumbed after 5 d stranded in shallow water. The dead fin whale was transported to a nearby pier...

  14. Fluid flow and heat transfer of a power-law fluid in an internally finned tube with different fin lengths

    Science.gov (United States)

    Grabski, Jakub Krzysztof; Kołodziej, Jan Adam

    2016-06-01

    In the paper an analysis of fluid flow and heat transfer of a power-law fluid in an internally finned tube with different fin length is conducted. Nonlinear momentum equation of a power-law fluid flow and nonlinear energy equation are solved using the Picard iteration method. Then on each iteration step the solution of inhomogeneous equation consists of two parts: the general solution and the particular solution. Firstly the particular solution is obtained by interpolation of the inhomogeneous term by means of the radial basis functions and monomials. Then the general solution is obtained using the method of fundamental solutions and by fulfilling boundary conditions.

  15. Heat exchanger with helical bundles of finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Eyking, H.J.

    1975-01-23

    The invention applies to a heat exchanger with helical bundles of tubes consisting of finned tubes separated by spacers. The spacers are designed as closed holding cylinders with holding devices for the tube bundles, each ot which surrounds a bundle of tubes. This construction serves to simplify the production process and to enable the use of the heat exchanger at higher loads.

  16. Zebrafish fin regeneration after cryoinjury-induced tissue damage

    Directory of Open Access Journals (Sweden)

    Bérénice Chassot

    2016-06-01

    Full Text Available Although fin regeneration following an amputation procedure has been well characterized, little is known about the impact of prolonged tissue damage on the execution of the regenerative programme in the zebrafish appendages. To induce histolytic processes in the caudal fin, we developed a new cryolesion model that combines the detrimental effects of freezing/thawing and ischemia. In contrast to the common transection model, the damaged part of the fin was spontaneously shed within two days after cryoinjury. The remaining stump contained a distorted margin with a mixture of dead material and healthy cells that concomitantly induced two opposing processes of tissue debris degradation and cellular proliferation, respectively. Between two and seven days after cryoinjury, this reparative/proliferative phase was morphologically featured by displaced fragments of broken bones. A blastemal marker msxB was induced in the intact mesenchyme below the damaged stump margin. Live imaging of epithelial and osteoblastic transgenic reporter lines revealed that the tissue-specific regenerative programmes were initiated after the clearance of damaged material. Despite histolytic perturbation during the first week after cryoinjury, the fin regeneration resumed and was completed without further alteration in comparison to the simple amputation model. This model reveals the powerful ability of the zebrafish to restore the original appendage architecture after the extended histolysis of the stump.

  17. Zebrafish Fins as a Model System for Skeletal Human Studies

    Directory of Open Access Journals (Sweden)

    Manuel Marí-Beffa

    2007-01-01

    Full Text Available Recent studies on the morphogenesis of the fins of Danio rerio (zebrafish during development and regeneration suggest that a number of inductive signals involved in the process are similar to some of those that affect bone and cartilage differentiation in mammals and humans. Akimenko et al. (2002 has shown that bone morphogenetic protein-2b (BMP2b is involved in the induction of dermal bone differentiation during fin regeneration. Many other groups have also shown that molecules from the transforming growth factor-beta superfamily (TGFβ, including BMP2, are effective in promoting chondrogenesis and osteogenesis in vivo in higher vertebrates, including humans. In the present study, we review the state of the art of this topic by a comparative analysis of skeletal tissue development, regeneration and renewal processes in tetrapods, and fin regeneration in fishes. A general conclusion of this study states that lepidotrichia is a special skeletal tissue different to cartilage, bone, enamel, or dentine in fishes, according to its extracellular matrix (ECM composition. However, the empirical analysis of inducing signals of skeletal tissues in fishes and tetrapods suggests that lepidotrichia is different to any responding features with main skeletal tissues. A number of new inductive molecules are arising from fin development and regeneration studies that might establish an empirical basis for further molecular approaches to mammal skeletal tissues differentiation. Despite the tissue dissimilarity, this empirical evidence might finally lead to clinical applications to skeletal disorders in humans.

  18. The Linear and Nonlinear Electro-MechanicalFin Actuator

    Directory of Open Access Journals (Sweden)

    Zeina A. Abdul Redha

    2011-01-01

    Full Text Available Electromechanical actuators are used in a wide variety of aerospace applications such as missiles, aircrafts and spy-fly etc. In this work a linear and nonlinear fin actuator mathematical model has been developed and its response is investigated by developing an algorithm for the system using MATLAB. The algorithm used to the linear model is the state space algorithm while the algorithm used to the nonlinear model is the discrete algorithm. The huge moment constant is varied from (-3000 to 3000 and the damping ratio is varied from (0.4 to 0.8. The comparison between linear and nonlinear fin actuator response results shows that for linear model, the maximum overshoot is about 10%, rising time is 0.23 sec. and steady state occur at 0.51 sec., while For nonlinear model the maximum overshoot is about 5%, rising time is 0.26 sec. and steady state occurs at 2 sec.; i.e., the nonlinear fin actuator system gives faster and more accurate response than does the linear fin actuator system.

  19. Biofluiddynamic scaling of flapping, spinning and translating fins and wings

    NARCIS (Netherlands)

    Lentink, D.; Dickinson, M.H.

    2009-01-01

    Organisms that swim or fly with fins or wings physically interact with the surrounding water and air. The interactions are governed by the morphology and kinematics of the locomotory system that form boundary conditions to the Navier–Stokes (NS) equations. These equations represent Newton's law of m

  20. Compensation of airflow maldistribution in fin-and-tube evaporators

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Tiedemann, Thomas

    2012-01-01

    Compensation of airflow maldistribution in fin-and tube evaporators for residential air-conditioning is investigated with regards to circuitry design and control of individual channel superheats. In particularly, the interlaced and the face split circuitry designs are compared numerically using...

  1. Novel FinFET Device Using Asymmetric Doping

    DEFF Research Database (Denmark)

    Moradi, Farshad

    2012-01-01

    In this paper, a new technique is proposed to improve the device characteristics by introducing asymmetric doping at the source and the drain of the conventional FinFET. Specifically, the proposed device exhibits 9X increase of the Ion/Ioff ratio and 3X improved DIBL compared to conventional...

  2. Locomotion of free-swimming ghost knifefish: anal fin kinematics during four behaviors.

    Science.gov (United States)

    Youngerman, Eric D; Flammang, Brooke E; Lauder, George V

    2014-10-01

    The maneuverability demonstrated by the weakly electric ghost knifefish (Apteronotus albifrons) is a result of its highly flexible ribbon-like anal fin, which extends nearly three-quarters the length of its body and is composed of approximately 150 individual fin rays. To understand how movement of the anal fin controls locomotion we examined kinematics of the whole fin, as well as selected individual fin rays, during four locomotor behaviors executed by free-swimming ghost knifefish: forward swimming, backward swimming, heave (vertical) motion, and hovering. We used high-speed video (1000 fps) to examine the motion of the entire anal fin and we measured the three-dimensional curvature of four adjacent fin rays in the middle of the fin during each behavior to determine how individual fin rays bend along their length during swimming. Canonical discriminant analysis separated all four behaviors on anal fin kinematic variables and showed that forward and backward swimming behaviors contrasted the most: forward behaviors exhibited a large anterior wavelength and posterior amplitude while during backward locomotion the anal fin exhibited both a large posterior wavelength and anterior amplitude. Heave and hover behaviors were defined by similar kinematic variables; however, for each variable, the mean values for heave motions were generally greater than for hovering. Individual fin rays in the middle of the anal fin curved substantially along their length during swimming, and the magnitude of this curvature was nearly twice the previously measured maximum curvature for ray-finned fish fin rays during locomotion. Fin rays were often curved into the direction of motion, indicating active control of fin ray curvature, and not just passive bending in response to fluid loading. Copyright © 2014 Elsevier GmbH. All rights reserved.

  3. Investigation of contact resistance for fin-tube heat exchanger by means of tube expansion

    Science.gov (United States)

    Hing, Yau Kar; Raghavan, Vijay R.; Meng, Chin Wai

    2012-06-01

    An experimental study on the heat transfer performance of a fin-tube heat exchanger due to mechanical expansion of the tube by bullets has been reported in this paper. The manufacture of a fin-tube heat exchanger commonly involves inserting copper tubes into a stack of aluminium fins and expanding the tubes mechanically. The mechanical expansion is achieved by inserting a steel bullet through the tube. The steel bullet has a larger diameter than the tube and the expansion provides a firm surface contact between fins and tubes. Five bullet expansion ratios (i.e. 1.045 to 1.059) have been used in the study to expand a 9.52mm diameter tubes in a fin-tube heat exchanger. The study is conducted on a water-to-water loop experiment rig under steady state conditions. In addition, the effects of fin hardness and fin pitch are investigated in the study. The results indicate that the optimum heat transfer occurred at a bullet expansion ratio ranging from 1.049 to 1.052. It is also observed that larger fin pitches require larger bullet expansion ratios, especially with lower fin hardness. As the fin pitch increases, both fin hardness (i.e. H22 and H24) exhibit increasing heat transfer rate per fin (W/fin). With the H22 hardness temper, the increase is as much as 11% while H24 increases by 1.2%.

  4. L'assignatura de Comerç Internacional: des de la teoria fins la pràctica

    OpenAIRE

    Iranzo Sancho, Susana

    2010-01-01

    En este artículo proponemos una práctica empírica para la asignatura de Comercio Internacional con la que los estudiantes puedan manejar estadísticas de comercio y acercarse así a la realidad del comercio mundial. El objetivo de la práctica es doble: por un lado, el estudiante aprende a interpretar y aplicar algunas teorías de comercio, extrayendo hipótesis contrastables empíricamente; por otro lado, se enfrenta a datos reales de comercio que debe tratar estadísticamente a fin y efecto de con...

  5. Transcriptional components of anteroposterior positional information during zebrafish fin regeneration.

    Science.gov (United States)

    Nachtrab, Gregory; Kikuchi, Kazu; Tornini, Valerie A; Poss, Kenneth D

    2013-09-01

    Many fish and salamander species regenerate amputated fins or limbs, restoring the size and shape of the original appendage. Regeneration requires that spared cells retain or recall information encoding pattern, a phenomenon termed positional memory. Few factors have been implicated in positional memory during vertebrate appendage regeneration. Here, we investigated potential regulators of anteroposterior (AP) pattern during fin regeneration in adult zebrafish. Sequence-based profiling from tissues along the AP axis of uninjured pectoral fins identified many genes with region-specific expression, several of which encoded transcription factors with known AP-specific expression or function in developing embryonic pectoral appendages. Transgenic reporter strains revealed that regulatory sequences of the transcription factor gene alx4a activated expression in fibroblasts and osteoblasts within anterior fin rays, whereas hand2 regulatory sequences activated expression in these same cell types within posterior rays. Transgenic overexpression of hand2 in all pectoral fin rays did not affect formation of the proliferative regeneration blastema, yet modified the lengths and widths of regenerating bones. Hand2 influenced the character of regenerated rays in part by elevation of the vitamin D-inactivating enzyme encoded by cyp24a1, contributing to region-specific regulation of bone metabolism. Systemic administration of vitamin D during regeneration partially rescued bone defects resulting from hand2 overexpression. Thus, bone-forming cells in a regenerating appendage maintain expression throughout life of transcription factor genes that can influence AP pattern, and differ across the AP axis in their expression signatures of these and other genes. These findings have implications for mechanisms of positional memory in vertebrate tissues.

  6. The Cx43-like connexin protein Cx40.8 is differentially localized during fin ontogeny and fin regeneration.

    Science.gov (United States)

    Gerhart, Sarah V; Eble, Diane M; Burger, R Michael; Oline, Stefan N; Vacaru, Ana; Sadler, Kirsten C; Jefferis, Rebecca; Iovine, M Kathryn

    2012-01-01

    Connexins (Cx) are the subunits of gap junctions, membraneous protein channels that permit the exchange of small molecules between adjacent cells. Cx43 is required for cell proliferation in the zebrafish caudal fin. Previously, we found that a Cx43-like connexin, cx40.8, is co-expressed with cx43 in the population of proliferating cells during fin regeneration. Here we demonstrate that Cx40.8 exhibits novel differential subcellular localization in vivo, depending on the growth status of the fin. During fin ontogeny, Cx40.8 is found at the plasma membrane, but Cx40.8 is retained in the Golgi apparatus during regeneration. We next identified a 30 amino acid domain of Cx40.8 responsible for its dynamic localization. One possible explanation for the differential localization is that Cx40.8 contributes to the regulation of Cx43 in vivo, perhaps modifying channel activity during ontogenetic growth. However, we find that the voltage-gating properties of Cx40.8 are similar to Cx43. Together our findings reveal that Cx40.8 exhibits differential subcellular localization in vivo, dependent on a discrete domain in its carboxy terminus. We suggest that the dynamic localization of Cx40.8 differentially influences Cx43-dependent cell proliferation during ontogeny and regeneration.

  7. The Cx43-like connexin protein Cx40.8 is differentially localized during fin ontogeny and fin regeneration.

    Directory of Open Access Journals (Sweden)

    Sarah V Gerhart

    Full Text Available Connexins (Cx are the subunits of gap junctions, membraneous protein channels that permit the exchange of small molecules between adjacent cells. Cx43 is required for cell proliferation in the zebrafish caudal fin. Previously, we found that a Cx43-like connexin, cx40.8, is co-expressed with cx43 in the population of proliferating cells during fin regeneration. Here we demonstrate that Cx40.8 exhibits novel differential subcellular localization in vivo, depending on the growth status of the fin. During fin ontogeny, Cx40.8 is found at the plasma membrane, but Cx40.8 is retained in the Golgi apparatus during regeneration. We next identified a 30 amino acid domain of Cx40.8 responsible for its dynamic localization. One possible explanation for the differential localization is that Cx40.8 contributes to the regulation of Cx43 in vivo, perhaps modifying channel activity during ontogenetic growth. However, we find that the voltage-gating properties of Cx40.8 are similar to Cx43. Together our findings reveal that Cx40.8 exhibits differential subcellular localization in vivo, dependent on a discrete domain in its carboxy terminus. We suggest that the dynamic localization of Cx40.8 differentially influences Cx43-dependent cell proliferation during ontogeny and regeneration.

  8. Constructal design of finned tubes used in air-cooled heat exchangers

    Energy Technology Data Exchange (ETDEWEB)

    Shokouhmand, Hossein; Mahjoub, Shoeib [University of Tehran, Tehran (Iran, Islamic Republic of); Salimpour, Mohammad Reza [Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

    2014-06-15

    The present study documents the constructal design and optimization of finned tubes used in air-cooled heat exchangers. The considered tubes are equipped with annular fins. The aim is to minimize the overall thermal resistance by morphing the geometry. The geometrical and thermo-physical parameters considered are the number of fins, ratio of fin height to tube diameter, Stanton number, ratio of fin conductivity to air conductivity, ratio of in-tube fluid conductivity to air conductivity and dimensionless pressure drop. Two constraints are applied in the optimization process: fixed overall volume of heat exchanger and fixed volume fraction of fin material. It is found that there exist optimal values for the number and the height of fins. Moreover, the optimal heat transfer has an extremum in a special volume fraction of fin material.

  9. Locomotion and Depth Control of Robotic Fish with Modular Undulating Fins

    Institute of Scientific and Technical Information of China (English)

    Kin Huat Low

    2006-01-01

    This paper presents an environmental-friendly robotic system mimicking the undulating fins of a fish. To mimic the actual flexible fin of real fish, a fin-like mechanism with a series of connecting linkages is modeled and attached to the robotic fish, by virtue of a specially designed strip. Each link is able to turn and slide with respect to the adjacent link.These driving linkages are then used to form a mechanical fin consisting of several fin segments, which are able to produce undulations, similar to those produced by the actual fish fins. Owing to the modular and re-configurable design of the mechanical fin, we are able to construct biomimetic robotic fish with various swimming modes by fin undulations. Some qualitative and workspace observations by experiments of the robotic fish are shown and discussed.

  10. Experimental study on thermal performance of micro pin fin heat sinks with various shapes

    Science.gov (United States)

    Hua, Junye; Li, Gui; Zhao, Xiaobao; Li, Qihe

    2017-03-01

    This paper presents a visualization experimental study on the heat transfer characteristics of various shapes of micro pin fins, including the circular, ellipse, diamond, square and triangle shape micro pin fin arrays with various equivalent diameters and pin fin density. The influences study of different sizes and shapes of pin fin on Nusselt number and heat transfer coefficient have been conducted. The results show that with the increase of the flow rate, the temperature of the bottom of the experimental section decreases. And the Nusselt number of different shapes of micro pin fins increases with the increase of Re. In which, the heat transfer performance of the ellipse shape pin fin appears better among the other shapes of pin fins. However, the higher pin fin of the ellipse shape density leads to a weaker flow performance. Besides, the micro-scale heat transfer correlation between the Nusselt number and the Reynolds number is fitted based on the experimental data.

  11. Numerical study of laminar free convection about a horizontal cylinder with longitudinal fins of finite thickness

    Energy Technology Data Exchange (ETDEWEB)

    Haldar, S.C.; Kochhar, G.S.; Manohar, K. [Department of Mechanical and Manufacturing Engineering, Faculty of Engineering, University of the West Indies, St. Augustine, Trinidad (Trinidad and Tobago); Tobago; Sahoo, R.K. [Department of Mechanical Engineering, National Institute of Technology, Rourkela (India)

    2007-07-15

    Conjugate numerical solution of laminar free convection about a horizontal cylinder with external longitudinal fins of finite thickness has been carried out. Fins alone contribute very small to the total heat transfer but they greatly influence the heat transfer from the uncovered area of the cylinder. Among the various fin parameters, thickness has the greatest influence on heat transfer. The rate of heat transfer is above that for the free cylinder only when the attached fins are very thin. For thin fins, there exist a fin length, which maximizes the rate of heat transfer. The optimum number and dimensionless length of the fins were obtained as 6 and 0.2 respectively when fin thickness is 0.01, the thinnest among those investigated in this study. (author)

  12. Four-Fin Bio-Inspired UUV: Modeling and Control Solutions

    Science.gov (United States)

    2011-01-01

    trailing fin interactions as outlined in the Fin Force Characterization section. 7 Copyright © 2011 by ASME Vehicle Control Architecture Adjustments...were made to the MBAB controller gains designed for the two-fin vehicle [13], but the architecture remains the same. Vehicle errors in surge motion...Sandberg, and B. Ratna, “Robotic Pectoral Fin Thrust Vectoring Using Weighted Gait Combinations”, submitted for publication in Applied Bionics and

  13. Experimental and numerical investigation to evaluate the performance of triangular finned tube heat exchanger

    OpenAIRE

    Vinous M. Hameed, Bashar Muslem Essa

    2015-01-01

    Experimental and numerical investigation has been performed in this work to evaluate the performance for triangular finned tube heat exchanger. Experimental work included designing and manufacturing of shaped triangular fins from copper material of (10mm) length, (10mm) height, (1mm) thickness, (22 mm) distance between every two fins shaped and (15mm) pitch between each two of fins which are install on the straight copper tube of (2m) length having (20mm) inner diameter and (22mm) outer diame...

  14. An experimental study on condensation heat transfer of low-finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Nae Hyun [University of Inchon, Inchon (Korea, Republic of); Jung, In Kwon; Kim, Kyung Hoon [Kumoh National University of Technology, Kumi (Korea, Republic of)

    1995-05-01

    Low-fin tubes are widely used to enhance condensation heat transfer. In this study. condensation heat transfer experiment was conducted on the low-fin tube using R-11. Three different fin densities-787 fpm (fins per meter), 1102 fpm. 1378 fpm-were tested. The results show that low-fin tube enhances the condensation heat transfer considerably. The enhancement increases as the fin density increases. It was also found that the fin shape and height have a significant effect on the condensation heat transfer coefficient. slender or high fins showed a higher condensing heat transfer coefficient compared with fat, low fins. For the tube with 1378 fpm, however, excessive fin height decreased the condensing heat transfer coefficient. The reason may be attributed to the increasing condensate retention angle as the fin density increases. The experimental data are compared with exiting prediction models. Results show that Webb`s surface tension model predicted the data best (within {+-} 20 %), which confirms that surface tension plays the major role in low-fin tube condensation. (author). 13 refs., 12 figs., 1 tab.

  15. EXPERIMENTAL STUDY ON ENHANCED HEAT TRANSFER WITH NI-BASED IMPLANTED SPIRAL FINNED TUBES

    Institute of Scientific and Technical Information of China (English)

    Sun Feng-zhong; Huang Xin-yuan; Wang Nai-hua; Shi Yue-tao; Ping Ya-ming

    2003-01-01

    The new type of heat exchanger elements-Ni-based Implanted Spiral Finned Turbes (NISFT) was studied and tested, which can contribute to increase the efficiency and reliability. The relation of Nu, Eu and Re with different fin pitch, fin height, transverse pitch and longitudinal pitch were gained, which constituted the basic foundation for the engineering application of NISFT.

  16. Experimental assessment of self-heating in SOI FinFETs

    NARCIS (Netherlands)

    Scholten, A.J.; Smit, G.D.J.; Pijper, R.M.T.; Tiemijer, L.F.; Tuinhout, H.P.; Steen, van der J.-L.P.J.; Mercha, A.; Braccioli, M.; Klaassen, D.B.M.

    2009-01-01

    In this paper, it is shown that self-heating causes a gigantic effect on the capacitances of MOSFETs/FinFETs. The effect is used to determine the SOI FinFET thermal impedance and to determine the temperature rise during FinFET operation

  17. Self-propelled flexible fin in the wake of a circular cylinder

    Science.gov (United States)

    Park, Sung Goon; Kim, Boyoung; Sung, Hyung Jin

    2016-11-01

    The behavior of a self-propelled flexible fin behind a circular cylinder in a uniform flow was explored using the immersed boundary method. The transverse heaving motion of the leading edge of the fin was prescribed, whereas the lateral behavior was spontaneously determined by the hydrodynamic interactions between the fin and the fluid environment. Three different behaviors were observed: propulsion upstream, drift downstream, and holding stationary at an equilibrium position. In a uniform flow, the fin could not overcome the positive net drag, and it drifted downstream. By contrast, a fin in the wake of a cylinder was propelled toward the circular cylinder during the heaving motion. The trailing edge of the fin passively fluttered along the oncoming vortices, thereby propelling the fin upstream. During the upstream propulsion behavior, the fin was propelled through the vortex cores. The fin was observed to remain stationary at a heaving frequency equal to the vortex shedding frequency, and a slaloming behavior was observed between the oncoming vortical structures. The fin was not propelled toward the cylinder during the slaloming behavior; rather, it lingered at a certain streamwise distance from the cylinder. Several equilibrium positions were dynamically determined from the interaction between the fin and the vortical fluid environment. The equilibrium position depended on the initial longitudinal position and the phase of the fin heaving motion with respect to the phase of the vortex shedding. The power input required to drive the heaving motion was reduced during the slaloming behavior.

  18. Experimental Simulation of Natural Heat Convection from Finned Vertical Plate with Different Inclinations

    Directory of Open Access Journals (Sweden)

    Saad Najeeb Shehab

    2016-09-01

    Full Text Available In this work an experimental simulation is made to predict the performance of steady-state natural heat convection along heated finned vertical base plate to ambient air with different inclination angles and configurations of fin array. Two types of fin arrays namely vertical fins array and V-fins array on heated vertical base plate are used with different heights and spaces. The influence of inclination angle of the plate , configuration of fins array and fin geometrical parameters such as fin height and fin spacing on the temperature distribution, base convection heat transfer coefficient and average Nusselt number have been plotted and discussed. The experimental data are correlated to a formula between average Nusselt number versus Rayleigh number for vertical plate and vertical fins array. The results indicate that the configuration of V-fins array gave best natural-convection heat transfer performance as base heat transfer coefficient about 20% greater compared with vertical fins array. Experimental simulation data and correlations of the present work are compared with a previous works shows good agreement

  19. Design, construction and testing of a prototype fin-line magic-tee and fin-line monopulse system suitable for millimeter-wave applications

    Science.gov (United States)

    Rowley, J. W.

    1985-12-01

    This thesis describes a fin-line 180 degree hybrid (magic-tee) that is suitable for use in monopulse radar antennas at microwave and millimeter-wave frequencies. The three-dimensional junction of a waveguide magic-tee is replaced with fin-line slots, coupled fin-line slots and microstrip lines mounted in a waveguide fixture. The planar geometry on the substrate provides significant reduction in size and eliminates the waveguide rat race that is associated with conventional hybrids. Ports one and two are flared into fin-line horns to produce a fin-line monopulse system. Suggestions for further development of the fin-line magic-tee and monopulse system are presented.

  20. Large Scale Density Estimation of Blue and Fin Whales: Utilizing Sparse Array Data to Develop and Implement a New Method for Estimating Blue and Fin Whale Density

    Science.gov (United States)

    2015-09-30

    1 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Large Scale Density Estimation of Blue and Fin Whales ...Utilizing Sparse Array Data to Develop and Implement a New Method for Estimating Blue and Fin Whale Density Len Thomas & Danielle Harris Centre...to develop and implement a new method for estimating blue and fin whale density that is effective over large spatial scales and is designed to cope

  1. Diagnóstico molecular para Leishmaniasis

    Directory of Open Access Journals (Sweden)

    Ysabel Montoya

    1997-01-01

    Full Text Available El potencial diagnóstico de epitopes inmunodominantes seleccionados fue ensayado satisfactoriamente a fin de obtener una prueba serodiagnóstica alternativa para la Leishmaniasis Tegumentaria Americana. Dos proteínas recombinantes prometedoras de L. (v. peruviana referidas como T-26-U2/T26-U4 fueron reconocidas por sueros individuales de pacientes con Leishmaniasis Tegumentaria Americana usando Western Blot. La sensibilidad de la prueba fue de 86% con sueros permanentes con Leishmaniasis peruana.

  2. BAT摩拳擦掌布局FinTech

    Institute of Scientific and Technical Information of China (English)

    薛健

    2016-01-01

    数据显示,2015年亚太区FinTech领域投资额的90%集中在中国,而BAT等互联网巨头则参与投资了40%以上的项目。花旗发布的一份研究报告显示,中国FinTech公司的用户数已经等同甚至超越中国最大的银行,并且"主要归因于阿里、百度、腾讯等互联网巨头在电子商务、第三方支付、网络借贷上的努力"。

  3. Performance Prediction of Cross-finned Tube Heat Exchangers

    Science.gov (United States)

    Kondou, Chieko; Senshu, Takao; Matsumura, Kenji; Oguni, Kensaku

    An important issue in heat pumps is increasing their efficiency, in order to achieve a significant optimization for heat exchangers. Techniques to simulate the flow length averaged heat transfer coefficient and static pressure drop through the flow passage are presented in this paper. In addition, an analytical evaluation of the cost reduction for a cross-fined tube heat exchanger of outdoor heat pump units is instantiated. The dimensionless factors, Colburn's factor j and Fanning's friction factor f, express the heat transfer performance and frictional characteristics, as a function of Reynolds number. These depend on slit possession, an original parameter used in this study. Further, this paper describes an approximate expression of the fin efficiency, which can be used for to survey the fin parameters. The above three concepts were necessary to forecast the performance on the airside. In the results, the cost minimum point was obtained with a comparable performance.

  4. Numerical Analysis of Tube-Fin Heat Exchanger using Fluent

    Directory of Open Access Journals (Sweden)

    M. V. Ghori

    2012-08-01

    Full Text Available Three-dimensional CFD simulations are carried out to investigate heat transfer and fluid flow characteristics of two-row plain Tube and Fin heat exchanger using FLUENT software. Heat transfer and pressure drop characteristics of the heat exchanger are investigated for Reynolds numbers ranging from 330 to 7000. Model geometry is created and meshed by using GAMBIT software. Fluid flow and heat transfer are simulated and results compared using both laminar and turbulent flow models k-, and SST k-omega, with steady-state solvers to calculate pressure drop, flow, and temperature fields. Model validation is carried out by comparing the simulated value friction factor f and Colburn factor j to experimental results investigate by Wang. Reasonable agreement is found between the simulations and experimental data, and the fluent software has been sufficient for simulating the flow fields in tube-fin heat exchangers.

  5. FLOW DISTRIBUTION IN A SOLAR COLLECTOR PANEL WITH HORIZONTAL FINS

    DEFF Research Database (Denmark)

    Fan, Jianhua; Shah, Louise Jivan; Furbo, Simon

    2005-01-01

    The objective of this work is to theoretically and experimentally investigate the flow and temperature distribution in a solar collector panel with an absorber consisting of horizontal fins. Fluid flow and heat transfer in the collector panel are studied by means of computational fluid dynamics...... (CFD) calculations. Further, experimental investigations of a 12.5 m² solar collector panel with 16 parallel connected horizontal fins are carried out. The flow distribution through the absorber is evaluated by means of temperature measurements on the backside of the absorber tubes. The measured......, temperature of inlet flow and collector tilt angle are shown. Based on the investigations preliminary recommendations for the operation of the investigated collector are given. For instance, minimum flow rate in order to avoid boiling in the horizontal strips is recommended....

  6. An experimental study of a pin-fin heat exchanger

    OpenAIRE

    Ramthun, David L.

    2003-01-01

    Approved for public release; distribution is unlimited A detailed experimental study has been carried out on the heat transfer and pressure drop characteristics of a compact heat exchanger with pin fins. A modular wind-tunnel with a rectangular cross-section duct-flow area was constructed that would accommodate the heat exchanger test section with varying pin designs. The flow in the tunnel was achieved through a suction-type blower, and a leading entrance length section was added to achie...

  7. Effect of Vapor Velocity during Condensation on Horizontal Finned Tubes

    Science.gov (United States)

    1988-12-01

    surface area (m2 ) b Fin spacing (mm) Ci Sieder -Tate type coefficient used in Equation (4.5) C p Specific heat of cooling water (J/kgK) Di Inside diameter...and auxiliary condensers, together with the energy lost to the environment. Raw data were processed immediately using an assumed value for the Sieder ...sets were collected, the data were reprocessed using a new Sieder -Tate coefficient found by the modified Wilson method. 40 F. TUBES TESTED For this

  8. Film Condensation of Steam on Externally Finned Horizontal Tubes.

    Science.gov (United States)

    1985-03-01

    Area Based on the Fin Diameter b - Experimentally Determined Constant B - Constant Used in the Sieder -Tate-Type Equation c - Experimentally Determined...Constant C - Leading Coefficient for the Sieder -Tate-Type Equation C1 - Constant of Proportionality d - Experimentally Determined Constant De...leading constants for the Sieder -Tate equation used to determine the water-side heat-transfer coefficient. Data taken on smooth tubes were used to

  9. Differential Transformation Method for Temperature Distribution in a Radiating Fin

    DEFF Research Database (Denmark)

    Rahimi, M.; Hosseini, M. J.; Barari, Amin

    2011-01-01

    Radiating extended surfaces are widely used to enhance heat transfer between a primary surface and the environment. In this paper, the differential transformation method (DTM) is proposed for solving nonlinear differential equation of temperature distribution in a heat radiating fin. The concept...... of differential transformation is briefly introduced, and then we employed it to derive solutions of two nonlinear equations. The results obtained by DTM are compared with those derived from the analytical solution to verify the accuracy of the proposed method....

  10. Optimization of fin geometry in heat convection with entransy theory

    Institute of Scientific and Technical Information of China (English)

    Cheng Xue-Tao; Zhang Qin-Zhao; Xu Xiang-Hua; Liang Xin-Gang

    2013-01-01

    The entransy theory developed in recent years is used to optimize the aspect ratio of a plate fin in heat convection.Based on a two-dimensional model,the theoretical analysis shows that the minimum thermal resistance defined with the concept of entransy dissipation corresponds to the maximum heat transfer rate when the temperature of the heating surface is fixed.On the other hand,when the heat flux of the heating surface is fixed,the minimum thermal resistance corresponds to the minimum average temperature of the heating surface.The entropy optimization is also given for the heat transfer processes.It is observed that the minimum entropy generation,the minimum entropy generation number,and the minimum revised entropy generation number do not always correspond to the best heat transfer performance.In addition,the influence factors on the optimized aspect ratio of the plate fin are also discussed.The optimized ratio decreases with the enhancement of heat convection,while it increases with fin thermal conductivity increasing.

  11. Layout of a latent heat storage system with finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, D.

    1980-10-26

    The theoretical and experimental investigations show by the example of Glauber's salt in a finned-tube latent heat storage vessel how heat transfer and storage capacity at charging and discharging depend on the variables of geometry, temperature, time and on the composition of the storing medium. By vertical arrangement of transversely finned tubes the separation problems occurring with Glauber's salt are solved insofar as the technical utilization of the latent heat of conversion corresponding to the complete conversion during charging and discharging not being possible, no decrease, of the reduced storage capacity, however, is found even after very many charging/discharging cycles. For the heat transfer during discharging correlations can be given on the basis of a model concept, be means of which a heat transfer coefficient, varying during the discharging process, can be predicted almost for the total range of discharge as a function of geometry, temperature and state of discharge. On the basis of the simple working formula for the heat transfer coefficient at crystallization of a latent heat storing medium the dynamic behavior of a compact finned-tube storage vessel can be predicted by means of a computer code. These means allow to perform the thermal design of a compact latent heat storage facility according to given design criteria accounting for economic aspects.

  12. High performance flexible CMOS SOI FinFETs

    KAUST Repository

    Fahad, Hossain M.

    2014-06-01

    We demonstrate the first ever CMOS compatible soft etch back based high performance flexible CMOS SOI FinFETs. The move from planar to non-planar FinFETs has enabled continued scaling down to the 14 nm technology node. This has been possible due to the reduction in off-state leakage and reduced short channel effects on account of the superior electrostatic charge control of multiple gates. At the same time, flexible electronics is an exciting expansion opportunity for next generation electronics. However, a fully integrated low-cost system will need to maintain ultra-large-scale-integration density, high performance and reliability - same as today\\'s traditional electronics. Up until recently, this field has been mainly dominated by very weak performance organic electronics enabled by low temperature processes, conducive to low melting point plastics. Now however, we show the world\\'s highest performing flexible version of 3D FinFET CMOS using a state-of-the-art CMOS compatible fabrication technique for high performance ultra-mobile consumer applications with stylish design. © 2014 IEEE.

  13. Brazed aluminum, Plate-fin heat exchangers for OTEC

    Energy Technology Data Exchange (ETDEWEB)

    Foust, H.D.

    1980-12-01

    Brazed aluminum plate-fin heat exchangers have been available for special applications for over thirty years. The performance, compactness, versatility, and low cost of these heat exchangers has been unequaled by other heat exchanger configuration. The application of brazed aluminum has been highly limited because of necessary restrictions for clean non-corrosive atmospheres. Air and gas separation have provided ideal conditions for accepting brazed aluminum and in turn have benefited by the salient features of these plate-fin heat exchangers. In fact, brazed aluminum and cryogenic gas and air separation have become nearly synonymous. Brazed aluminum in its historic form could not be considered for a seawater atmosphere. However, technology presents a new look of significant importance to OTEC in terms of compactness and cost. The significant technological variation made was to include one-piece hollow extensions for the seawater passages. Crevice corrosion sites are thereby entirely eliminated and pitting corrosion attack will be controlled by an integral and sacrificial layer of a zinc-aluminum alloy. This paper on brazed aluminum plate-fin heat exchangers for OTEC will aquaint the reader with the state-of-art and variations suggested to qualify this form of aluminum for seawater use. In order to verify the desirable cost potential for OTEC, Trane teamed with Westinghouse to perform an OTEC system analysis with this heat exchanger. These results are very promising and reported in detail elsewhere.

  14. Numerical Study on Hydrodynamic Performance of Bionic Caudal Fin

    Directory of Open Access Journals (Sweden)

    Kai Zhou

    2016-01-01

    Full Text Available In this work, numerical simulations are conducted to reveal the hydrodynamic mechanism of caudal fin propulsion. In the modeling of a bionic caudal fin, a universal kinematics model with three degrees of freedom is adopted and the flexible deformation in the spanwise direction is considered. Navier-Stokes equations are used to solve the unsteady fluid flow and dynamic mesh method is applied to track the locomotion. The force coefficients, torque coefficient, and flow field characteristics are extracted and analyzed. Then the thrust efficiency is calculated. In order to verify validity and feasibility of the algorithm, hydrodynamic performance of flapping foil is analyzed. The present results of flapping foil compare well with those in experimental researches. After that, the influences of amplitude of angle of attack, amplitude of heave motion, Strouhal number, and spanwise flexibility are analyzed. The results show that, the performance can be improved by adjusting the motion and flexibility parameters. The spanwise flexibility of caudal fin can increase thrust force with high propulsive efficiency.

  15. Simulation Studies on A Cross Flow Plate Fin Heat Exchanger

    Directory of Open Access Journals (Sweden)

    M. Thirumarimurugan

    2008-01-01

    Full Text Available Compact heat exchangers which were initially developed for the aerospace industries in the1940s have been considerably improved in the past few years. The main reasons for the goodperformance of compact heat exchangers are their special design which includes turbulent which inturn use high heat transfer coefficient and resists fouling, and maximum temperature driving forcebetween the hot and cold fluids. Numerous types use special enhancement techniques to achieve therequired heat transfer in smaller plot areas and, in many cases, less initial investment. One such type ofcompact heat exchanger is the Plate-fin heat exchanger. The complexity of compact heat exchangerdesign equations results from the exchangers unique ability to transfer heat between multiple processstreams and a wide array of possible flow configurations. This paper presents the performanceevaluation of cross flow plate fin heat exchanger with several different Gas-Liquid systems.Experimental results such as exchanger effectiveness, overall heat transfer coefficients were calculatedfor the flow systems of Cross flow Heat Exchangers. A steady state model for the outlet temperature ofboth the cold and hot fluid and overall heat transfer coefficient of a plate-fin cross flow heat exchangerwas developed and simulated using MATLAB, which was verified with the experiments conducted.

  16. Bionic asymmetry: from amiiform fish to undulating robotic fins

    Institute of Scientific and Technical Information of China (English)

    HU TianJiang; SHEN LinCheng; LOW K.H.

    2009-01-01

    Similar to bionic non-smooth which has been successfully applied in anti-resistance and anti-adhesion, bionic asymmetry is also an inherent property of biological systems and is worth exploring for con-ceivable pragmatic applications. Therefore, bionic asymmetry for undulations is of main interest in this paper. We initially investigate bionic asymmetry with a case study of the undulating robotic fin, RoboGnilos, which evolved from the long dorsal fin of Gymnarchus niloticus in the amiiforrn mode. Since the performance of the pre-existing undulating fins is hardly satisfactory, we obtain bionic in-spirations of undulatory asymmetry through observations and measurements on the specimen of G. niloticus, to improve upon the performance. Consequently, the newly acquired innovation for bionic asymmetry is incorporated into the previously derived kinematics model, and also applied to the ex-perimental prototype. Both computational and experimental results verify that bionic asymmetric un-dulation generates better propulsion performance (in terms of linear velocity and efficiency) than the traditional symmetric modes with the same undulatory parameters.

  17. Un modelo Macroeconométrico para la Economía Colombiana.

    Directory of Open Access Journals (Sweden)

    Javier Arturo Birchenall

    2010-05-01

    Full Text Available Este documento analiza un modelo macroeconométrico de corto plazo para la economía colombiana, con el fin de evaluar el impacto de procesos de ajuste y estabilización. Se basa en una estructura que reconoce no neutralidades por rigideces de precios y descompone la economía a través de oferta y demanda agregada. El modelo se estima por diversos métodos para el período comprendido entre 1977 y 1998 con una frecuencia trimestral, con el fin de realizar proyecciones para períodos de uno y dos años.

  18. Un modelo Macroeconométrico para la Economía Colombiana.

    OpenAIRE

    2010-01-01

    Este documento analiza un modelo macroeconométrico de corto plazo para la economía colombiana, con el fin de evaluar el impacto de procesos de ajuste y estabilización. Se basa en una estructura que reconoce no neutralidades por rigideces de precios y descompone la economía a través de oferta y demanda agregada. El modelo se estima por diversos métodos para el período comprendido entre 1977 y 1998 con una frecuencia trimestral, con el fin de realizar proyecciones para períodos de...

  19. Prediction of forces and moments on finned bodies at high angle of attack in transonic flow

    Energy Technology Data Exchange (ETDEWEB)

    Oberkampf, W. L.

    1981-04-01

    This report describes a theoretical method for the prediction of fin forces and moments on bodies at high angle of attack in subsonic and transonic flow. The body is assumed to be a circular cylinder with cruciform fins (or wings) of arbitrary planform. The body can have an arbitrary roll (or bank) angle, and each fin can have individual control deflection. The method combines a body vortex flow model and lifting surface theory to predict the normal force distribution over each fin surface. Extensive comparisons are made between theory and experiment for various planform fins. A description of the use of the computer program that implements the method is given.

  20. Armamento é Direitos Humanos: nossos fins, os meios e seus modos

    Directory of Open Access Journals (Sweden)

    Jacqueline de Oliveira Muniz

    2013-04-01

    Full Text Available A definição da capacidade coercitiva da polícia é a condição de possibilidade de sua instrumentalidade política para a defesa dos Direitos Humanos, bem como de sua governança. Após uma apresentação que consolida a teorização sobre o uso de força para a produção de obediências consentidas, apresentam-se três passagens históricas que correspondem aos momentos fundacionais das polícias modernas como ilustrações das alternativas de definição de tal capacidade, exemplificando diferentes formas de se conectar fins e meios, preferências políticas e especificidade de armamentos. As questões que essas exposições suscitam permitem apresentar duas considerações relevantes para o debate brasileiro sobre segurança pública: a tensão entre universalidade e localismo no instrumento policial, e a integralidade de fins e meios em duas instâncias em que o uso de força pode ter lugar - a defesa e a segurança pública.The definition of the coercive capacity of the police is the condition of possibility for its political instrumentality as well as its governance. After a presentation that consolidates the theorization of the use of force for the production of consented obediences, the article presents three passages of foundational moments of modern police forces as illustrations of the alternative ways of defining that capability as examples of different ways of connecting ends and means, political preferences and weapons specifics. The issues that these bring about allow the presentation of two issues relevant to the brazilian debate on public security: the tension between universality and localism in the police instrument and the integral nature of ends and means in two instances which admit the possibility of the use of force - defense and public security.

  1. Multi-Subband Monte Carlo simulations of IONION degradation due to fin thickness fluctuations in FinFETs

    Science.gov (United States)

    Serra, N.; Palestri, P.; Smit, G. D. J.; Selmi, L.

    2009-04-01

    The impact of fin thickness nonuniformities on carrier transport in n-type FinFETs is analyzed with a Multi-Subband Monte Carlo technique, which allows for an accurate description of the quasi-ballistic transport taking place in short channel devices and which comprises the dominant scattering mechanisms as well as a semi-empirical technique to handle quantization effects in the transport direction. We found that the impact of channel thickness discontinuity on the on-current is larger when the nonuniformities are located close to the Virtual Source of the device. Furthermore, the sensitivity of the on-current to thickness nonuniformity is essentially the same when considering devices with different crystal orientations. Comparison with drift-diffusion simulations reveals substantial differences in the predicted trends of the sensitivity of the drain current to thickness fluctuations in these nanoscale devices.

  2. Formation of integral fins function-surface by extrusion-ploughing process

    Institute of Scientific and Technical Information of China (English)

    CHEN Ping; TANG Yong; LIU Xiao-kang; LIU Xiao-qing

    2006-01-01

    An extrusion-ploughing process was presented to fabricate the integral fin function-surface. Cutting edge inclination angle and rake angle can be calculated from the tool's geometry relationship. The description of fins' geometry characters was standardized. The experiments show that, when the middle cutting edge's inclination angle η is less than 35-, continuous fin will come out; when η is between 35- and 55-, the fins will be saw-tooth ones, and the fins will be torn when this angle is above 55-; when the extrusion angle θ is between 60- and 150-, the fins will appear, or else, the fins will be torn into chips from the base. Forming angle and clearance angle have little effect on fin's formation. For continuous fin, its height is close to cutting depth when it is small, but it will become approximately constant as cutting depth grows; for saw-tooth fins, the width, the height, as well as the clearance will increase with the increase of cutting depth, but the increment of clearance is small; neither for continuous fin, nor for saw-tooth ones, cutting velocity has little influence on their structure parameters.

  3. Fish larvae exploit edge vortices along their dorsal and ventral fin folds to propel themselves.

    Science.gov (United States)

    Li, Gen; Müller, Ulrike K; van Leeuwen, Johan L; Liu, Hao

    2016-03-01

    Larvae of bony fish swim in the intermediate Reynolds number (Re) regime, using body- and caudal-fin undulation to propel themselves. They share a median fin fold that transforms into separate median fins as they grow into juveniles. The fin fold was suggested to be an adaption for locomotion in the intermediate Reynolds regime, but its fluid-dynamic role is still enigmatic. Using three-dimensional fluid-dynamic computations, we quantified the swimming trajectory from body-shape changes during cyclic swimming of larval fish. We predicted unsteady vortices around the upper and lower edges of the fin fold, and identified similar vortices around real larvae with particle image velocimetry. We show that thrust contributions on the body peak adjacent to the upper and lower edges of the fin fold where large left-right pressure differences occur in concert with the periodical generation and shedding of edge vortices. The fin fold enhances effective flow separation and drag-based thrust. Along the body, net thrust is generated in multiple zones posterior to the centre of mass. Counterfactual simulations exploring the effect of having a fin fold across a range of Reynolds numbers show that the fin fold helps larvae achieve high swimming speeds, yet requires high power. We conclude that propulsion in larval fish partly relies on unsteady high-intensity vortices along the upper and lower edges of the fin fold, providing a functional explanation for the omnipresence of the fin fold in bony-fish larvae.

  4. Geometrical optimization and mould wear effect on HPD type steel offset strip fin performance

    Energy Technology Data Exchange (ETDEWEB)

    Lihua, Guo; Jiangping, Chen; Feng, Qin; Zhijiu, Chen [Institute of Refrigeration and Cryogenics Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai 200030 (China)

    2007-09-15

    Aiming at studying the influence and importance of the geometrical parameters on steel HPD type offset strip fin performance, this paper reports experimental and numerical studies at low Reynolds number. A novel test rig with electrically heated single layer fin assembly as test object was constructed. Only the effects of fin height and fin wavelength on the fin characteristics were considered because of the pressing mould limitation. Through comparisons of experimental, simulated and Muzychka's results, the tendencies agree well. The deviations between them are due to the difference of fin material and the influences of the pressing mould process technique on the fins. Based on the Taguchi method and uniform design, the importance of the geometrical factors on the fin thermal-hydraulic performance was investigated. The sequence of degrees of effect for each parameter is s, h, {alpha}, s{sub 0}, b and t. The paper obtained the optimum model and numerically proved its validity among the considered ranges. Eleven sample fins were collected during different periods of the mould life time, and the influences of mould wear on fin friction performance were examined. The mould wear includes three stages, and the performance of fins pressed during 100 thousand times to 1,050 thousand times is more stable. The recommended life time for the mould type is about 1,050 thousand times. (author)

  5. A new system for analyzing swim fin propulsion based on human kinematic data.

    Science.gov (United States)

    Nicolas, Guillaume; Bideau, Benoit; Bideau, Nicolas; Colobert, Briac; Le Guerroue, Gaël; Delamarche, Paul

    2010-07-20

    The use of swim fins has become popular in various water sport activities. While numerous models of swim fin with various innovative shapes have been subjectively designed, the exact influence of the fin characteristics on swimming performance is still much debated, and remains difficult to quantify. To date, the most common approach for evaluating swim fin propulsion is based on the study of "swimmer-fins" as a global system, where physiological and/or biomechanical responses are considered. However, reproducible swimming technique is difficult (or even impossible) to obtain on human body and may lead to discrepancies in data acquired between trials. In this study, we present and validate a new automat called HERMES which enables an evaluation of various swim fins during an adjustable, standardized and reproducible motion. This test bench reliably and accurately reproduces human fin-swimming motions, and gives resulting dynamic measurements at the ankle joint. Seven fins with various geometrical and mechanical characteristics were tested. For each swim fin, ankle force and hydromechanical efficiency (useful mechanical power output divided by mechanical power input delivered by the motors) were calculated. Efficiencies reported in our study were high (close to 70% for some swim fins) over a narrow range of Strouhal number (St) and peaks within the interval 0.2swimming animals. Therefore, an interesting prospect in this work would be to accurately study the impact of adjustable fin kinematics and material (design and mechanical properties) on the wake structure and on efficiency.

  6. Fin de vida en residencia de ancianos desde la perspectiva de los residentes: revisión bibliográfica

    Directory of Open Access Journals (Sweden)

    Manuel Guerrero García

    Full Text Available Objetivos: Describir cómo se desarrollan los procesos de fin de vida en las residencias de ancianos desde la perspectiva de los residentes. Metodología: Revisión bibliográfica en distintas bases de datos, en los últimos 10 años. Las bases de datos consultadas fueron Cuiden, IME, Elsevier, PubMed y CINALH. Se excluyeron aquellos artículos que no estudiaban las experiencias u opiniones de los residentes. Resultados: De los 305 artículos encontrados, se eliminaron los que no cumplían con los criterios de inclusión y exclusión. Finalmente se seleccionaron13 artículos. Algunos de los temas que se abordan son las necesidades que los residentes consideran más importantes, aspectos indicativos de buena muerte y la relación del dolor con la calidad de los procesos de fin de vida. Conclusión: Los resultados de este estudio demuestran lo poco que se sabe sobre los procesos de fin de vida en las residencias de ancianos de nuestro país. La falta de evidencia en este sentido no nos permite asegurar que las residencias sean un lugar adecuado para el desarrollo de los procesos de fin de vida.

  7. The influence of culture on the international management of shark finning.

    Science.gov (United States)

    Dell'Apa, Andrea; Smith, M Chad; Kaneshiro-Pineiro, Mahealani Y

    2014-08-01

    Shark finning is prohibited in many countries, but high prices for fins from the Asian market help maintain the international black-market and poaching. Traditional shark fin bans fail to recognize that the main driver of fin exploitation is linked to cultural beliefs about sharks in traditional Chinese culture. Therefore, shark finning should be addressed considering the social science approach as part of the fishery management scheme. This paper investigates the cultural significance of sharks in traditional Chinese and Hawaiian cultures, as valuable examples of how specific differences in cultural beliefs can drive individuals' attitudes toward the property of shark finning. We suggest the use of a social science approach that can be useful in the design of successful education campaigns to help change individuals' attitudes toward shark fin consumption. Finally, alternative management strategies for commercial fishers are provided to maintain self-sustainability of local coastal communities.

  8. A Novel Implementation of a Flexible Robotic Fin Actuated by Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Qin Yan; Lei Wang; Bo Liu; Jie Yang; Shiwu Zhang

    2012-01-01

    In this paper,study of a novel flexible robotic-fin actuated by Shape Memory Alloy (SMA) is presented.The developed robotic fin is capable of implementing various 3-Dimensional (3D) motions,which plays an important role in robot propulsion and maneuverability.Firstly,the morphological and mechanics parameters of a real pectoral fin from a carp are investigated.Secondly,a detailed design of the flexible pectoral fin driven by SMA is presented according to the previous morphological and mechanics analyses.Thirdly,a simplified theoretical model on the SMA fin plate is derived.The thermodynamics of the SMA plate and the relationship between curvature and phase transformation are analyzed.Finally,several simulations and model experiments are conducted according to the previous analyses.The results of the experiments are useful for the control of the robotic fin.The experimental results reveal that the SMA actuated fin ray has a good actuating performance.

  9. A shift in anterior-posterior positional information underlies the fin-to-limb evolution.

    Science.gov (United States)

    Onimaru, Koh; Kuraku, Shigehiro; Takagi, Wataru; Hyodo, Susumu; Sharpe, James; Tanaka, Mikiko

    2015-08-18

    The pectoral fins of ancestral fishes had multiple proximal elements connected to their pectoral girdles. During the fin-to-limb transition, anterior proximal elements were lost and only the most posterior one remained as the humerus. Thus, we hypothesised that an evolutionary alteration occurred in the anterior-posterior (AP) patterning system of limb buds. In this study, we examined the pectoral fin development of catshark (Scyliorhinus canicula) and revealed that the AP positional values in fin buds are shifted more posteriorly than mouse limb buds. Furthermore, examination of Gli3 function and regulation shows that catshark fins lack a specific AP patterning mechanism, which restricts its expression to an anterior domain in tetrapods. Finally, experimental perturbation of AP patterning in catshark fin buds results in an expansion of posterior values and loss of anterior skeletal elements. Together, these results suggest that a key genetic event of the fin-to-limb transformation was alteration of the AP patterning network.

  10. Design optimization of pin fin geometry using particle swarm optimization algorithm.

    Directory of Open Access Journals (Sweden)

    Nawaf Hamadneh

    Full Text Available Particle swarm optimization (PSO is employed to investigate the overall performance of a pin fin.The following study will examine the effect of governing parameters on overall thermal/fluid performance associated with different fin geometries, including, rectangular plate fins as well as square, circular, and elliptical pin fins. The idea of entropy generation minimization, EGM is employed to combine the effects of thermal resistance and pressure drop within the heat sink. A general dimensionless expression for the entropy generation rate is obtained by considering a control volume around the pin fin including base plate and applying the conservations equations for mass and energy with the entropy balance. Selected fin geometries are examined for the heat transfer, fluid friction, and the minimum entropy generation rate corresponding to different parameters including axis ratio, aspect ratio, and Reynolds number. The results clearly indicate that the preferred fin profile is very dependent on these parameters.

  11. Room-temperature direct band-gap electroluminescence from germanium (111)-fin light-emitting diodes

    Science.gov (United States)

    Tani, Kazuki; Saito, Shin-ichi; Oda, Katsuya; Miura, Makoto; Wakayama, Yuki; Okumura, Tadashi; Mine, Toshiyuki; Ido, Tatemi

    2017-03-01

    Germanium (Ge) (111) fins of 320 nm in height were successfully fabricated using a combination of flattening sidewalls of a silicon (Si) fin structure by anisotropic wet etching with tetramethylammonium hydroxide, formation of thin Ge fins by selective Si oxidation in SiGe layers, and enlargement of Ge fins by Ge homogeneous epitaxial growth. The excellent electrical characteristics of Ge(111) fin light-emitting diodes, such as an ideality factor of 1.1 and low dark current density of 7.1 × 10‑5 A cm‑2 at reverse bias of ‑2 V, indicate their good crystalline quality. A tensile strain of 0.2% in the Ge fins, which originated from the mismatch of the thermal expansion coefficients between Ge and the covering SiO2 layers, was expected from the room-temperature photoluminescence spectra, and room-temperature electroluminescence corresponding to the direct band-gap transition was observed from the Ge fins.

  12. The Influence of Culture on the International Management of Shark Finning

    Science.gov (United States)

    Dell'Apa, Andrea; Chad Smith, M.; Kaneshiro-Pineiro, Mahealani Y.

    2014-08-01

    Shark finning is prohibited in many countries, but high prices for fins from the Asian market help maintain the international black-market and poaching. Traditional shark fin bans fail to recognize that the main driver of fin exploitation is linked to cultural beliefs about sharks in traditional Chinese culture. Therefore, shark finning should be addressed considering the social science approach as part of the fishery management scheme. This paper investigates the cultural significance of sharks in traditional Chinese and Hawaiian cultures, as valuable examples of how specific differences in cultural beliefs can drive individuals' attitudes toward the property of shark finning. We suggest the use of a social science approach that can be useful in the design of successful education campaigns to help change individuals' attitudes toward shark fin consumption. Finally, alternative management strategies for commercial fishers are provided to maintain self-sustainability of local coastal communities.

  13. A Computational Fluid Dynamics (CFD) Analysis of an Undulatory Mechanical Fin Driven by Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Yong-Hua Zhang; Jian-Hui He; Jie Yang; Shi-Wu Zhang; Kin Huat Low

    2006-01-01

    Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy (SMA). The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured,grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin (amplitude, frequency and wavelength).

  14. Familia - Escuela - Comunidad: pilares para la inclusión

    Directory of Open Access Journals (Sweden)

    Rafael Bell Rodríguez

    2010-01-01

    Full Text Available En el artículo se aborda, desde la perspectiva del enfoque histórico-cultural, la necesidad del establecimiento de una sólida relación familia-escuela-comunidad a fin de asegurar su decisiva contribución para el logro del real acceso de las personas con alguna discapacidad a la cultura, que se reconoce como la más prometedora vía para su desarrollo humano.

  15. An improved model for predicting performance of finned tube heat exchanger under frosting condition, with frost thickness variation along fin

    Energy Technology Data Exchange (ETDEWEB)

    Tso, C.P. [Multimedia University, Jalan Ayer Keroh Lama, Melaka (Malaysia). Faculty of Engineering and Technology; Cheng, Y.C.; Lai, A.C.K. [Nanyang Technological University, Singapore (Singapore). School of Mechanical and Aerospace Engineering

    2006-01-15

    Frost accumulation on a heat exchanger, a direct result of combined heat and mass transfer between the moist air flowing across a cold surface, causes heat transfer performance degradation due to the insulating effect of frost layer and the coil blockage as the frost grows. The complex geometry of finned tube heat exchangers leads to uneven wall and air temperature distribution inside the coil, and causes variations of frost growth rate and densification along the coil. In this study, a general distributed model with frost formation was developed. The equations for finned tube heat exchanger were derived in non-steady-state manner and quasi-steady state in the frost model. In order to make the model more realistic, the variation of frost along fin due to uneven temperature distribution was included. The presented model is able to predict the dynamic behavior of an air cooler both under non-frost and frost condition. Comparisons were made based on the frost mass accumulation, pressure drop across coil and energy transfer coefficient, and results were found to agree well with reported experimental results. (author)

  16. Performance enhancement of fin attached ice-on-coil type thermal storage tank for different fin orientations using constrained and unconstrained simulations

    Science.gov (United States)

    Kim, M. H.; Duong, X. Q.; Chung, J. D.

    2016-07-01

    One of the drawbacks in latent thermal energy storage system is the slow charging and discharging time due to the low thermal conductivity of the phase change materials (PCM). This study numerically investigated the PCM melting process inside a finned tube to determine enhanced heat transfer performance. The influences of fin length and fin numbers were investigated. Also, two different fin orientations, a vertical and horizontal type, were examined, using two different simulation methods, constrained and unconstrained. The unconstrained simulation, which considers the density difference between the solid and liquid PCM showed approximately 40 % faster melting rate than that of constrained simulation. For a precise estimation of discharging performance, unconstrained simulation is essential. Thermal instability was found in the liquid layer below the solid PCM, which is contrary to the linear stability theory, due to the strong convection driven by heat flux from the coil wall. As the fin length increases, the area affected by the fin becomes larger, thus the discharging time becomes shorter. The discharging performance also increased as the fin number increased, but the enhancement of discharging performance by more than two fins was not discernible. The horizontal type shortened the complete melting time by approximately 10 % compared to the vertical type.

  17. Performance enhancement of fin attached ice-on-coil type thermal storage tank for different fin orientations using constrained and unconstrained simulations

    Science.gov (United States)

    Kim, M. H.; Duong, X. Q.; Chung, J. D.

    2017-03-01

    One of the drawbacks in latent thermal energy storage system is the slow charging and discharging time due to the low thermal conductivity of the phase change materials (PCM). This study numerically investigated the PCM melting process inside a finned tube to determine enhanced heat transfer performance. The influences of fin length and fin numbers were investigated. Also, two different fin orientations, a vertical and horizontal type, were examined, using two different simulation methods, constrained and unconstrained. The unconstrained simulation, which considers the density difference between the solid and liquid PCM showed approximately 40 % faster melting rate than that of constrained simulation. For a precise estimation of discharging performance, unconstrained simulation is essential. Thermal instability was found in the liquid layer below the solid PCM, which is contrary to the linear stability theory, due to the strong convection driven by heat flux from the coil wall. As the fin length increases, the area affected by the fin becomes larger, thus the discharging time becomes shorter. The discharging performance also increased as the fin number increased, but the enhancement of discharging performance by more than two fins was not discernible. The horizontal type shortened the complete melting time by approximately 10 % compared to the vertical type.

  18. Daño cerebral provocado por el consumo de alcohol de fin de semana: un estudio neurotoxicológico y farmacocinético en animales de experimentación

    OpenAIRE

    Manzini, Fernando A.

    2011-01-01

    Investigaciones neuropsicológicas recientes demostraron que el consumo de alcohol de fin de semana suele asociarse a severas alteraciones cognitivas tales como déficits en las funciones ejecutivas y amnesia anterógrada para material verbal. De la mano de estos estudios, investigaciones experimentales en roedores demostraron que una administración de alcohol de 9 a 12 g/kg por día durante 2 o 4 días (administración experimental que intenta modelar el consumo de alcohol de fin de semana), provo...

  19. La Administración electrónica aplicada a la gestión de los trabajos fin de grado en ingeniería informática

    OpenAIRE

    Sama Villanueva, Sergio; Secundino GONZÁLEZ; López, Benjamín; Juan, Aquilino; Riesco Albizu, Miguel

    2014-01-01

    La Universidad de Oviedo, al igual que otras universidades, con la adaptación de sus estudios al Espacio Europeo de Educación Superior1 (EEES), se encuentra con la obligación de incorporar en todos los estudios que se imparten una asignatura obligatoria, ya conocida en la titulaciones de ingeniería con el nombre de Trabajo Fin de Carrera (TFC), pero nueva para el resto de titulaciones, que pasa a conocerse con el nombre de Trabajo Fin de Grado, haciendo alusión al p...

  20. Regulation of use of radiation for quarantine purposes; Regulamentacao do uso da radiacao para fins quarentenarios

    Energy Technology Data Exchange (ETDEWEB)

    Itepan, Natanael Marcio, E-mail: natanael.itepan@unianhanguera.edu.b [Faculdade Anhanguera, Piracicaba, SP (Brazil); Costa, Neivaldo; Furlan, Gilberto Ribeiro; Walder, Julio Marcos Melges, E-mail: neivaldo@cena.usp.b, E-mail: gilfurlan@cena.usp.b, E-mail: jmwalder@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

    2011-07-01

    The main aspects of Instruction No. 9 are: a) the nuclear plant that use ionizing radiation as a phyto sanitary treatment for quarantine purposes, must be accredited by the agency of the Agriculture, Livestock and Supply Ministry (MAPA) and the licensing by the Nuclear Energy National Commission (CNEN) and other regulatory bodies, b) control of the applied dose will follow a standard operating procedure should be performed by independent organization, authorized by the Brazilian ONPF (Phyto sanitary Protection National Organization), c) the unit of radiation treatment should ensure traceability and must maintain records of phyto sanitary treatments, d) there should be bilateral work plan between the ONPF of Brazil and other countries for the established radiation treatment protocol. The ONPF of Brazil is the Sanitary Vegetarian Department. Ionizing radiation (cold pasteurization) is shown in an alternative technology to phyto sanitary control for quarantine purposes. (author)

  1. Del Paseo de las Delicias a Corrientes: El largo fin de la guerra para un soldado

    Directory of Open Access Journals (Sweden)

    Natalia Corbellini

    2006-11-01

    Full Text Available The text refers an interview maintained with a republican soldier that it gets ready in Madrid, and the end of the war finds him passing to France by Catalunya. The dialogue reflects the long way that had to journey that young soldier, after supporting the French concentration camps, in order to be able to arrive at Monte Caseros, a small town of the Argentine coast where part of his family waited for him, so that he could settle down and take ahead a life.

  2. Effect of Fin Geometry on Condensation of Zeotropic Refrigerant Mixture R407C in a Staggered Bundle of Horizontal Finned Tubes

    Science.gov (United States)

    Honda, Hiroshi; Takata, Nobuo; Takamatsu, Hiroshi; Kim, Jeongsik; Usami, Keiichiro

    Row-by-row heat transfer data were obtained during condensation of downward-flowing refrigerant mixture R407C in a staggered bundle of horizontal finned tubes. Two kinds of conventional low-fin tubes with flat-sided annular fins and three kinds of three-dimensional fin tubes were tested. The refrigerant mass velocity ranged from 4 to 23 kg/m2s, and the condensation temperature difference from 1.5 to 12 K. At a low to medium film Reynolds number(2000), on the other hand, the highest performance was obtained by one of the low-fin tubes. For all tubes tested, the heat transfer coefficient decreased with decreasing mass velocity. On the basis of previous results for R134a, consideration was given to the characteristics of vapor phase mass transfer of R407C.

  3. Patterning challenges in advanced device architectures: FinFETs to nanowires

    Science.gov (United States)

    Horiguchi, N.; Milenin, A. P.; Tao, Z.; Hubert, H.; Altamirano-Sanchez, E.; Veloso, A.; Witters, L.; Waldron, N.; Ragnarsson, L.-Å.; Kim, M. S.; Kikuchi, Y.; Mertens, H.; Raghavan, P.; Piumi, D.; Collaert, N.; Barla, K.; Thean, A. V.

    2016-03-01

    Si FinFET scaling is getting more difficult due to extremely narrow fin width control and power dissipation. Nanowire FETs and high mobility channel are attractive options for CMOS scaling. Nanowire FETs can maintain good electrostatics with relaxed nanowire diameter. High mobility channel can provide good performance at low power operation. However their fin patterning is challenging due to fins consisted of different materials or fragile high mobility material. Controlled etch and strip are necessary for good fin cd and profile control. Fin height increase is a general trend of scaled FinFETs and nanowire FETs, which makes patterning difficult not only in fin, but also in gate, spacer and replacement metal gate. It is important that gate and spacer etch have high selectivity to fins and good cd and profile control even with high aspect ratio of fin and gate. Work function metal gate patterning in scaled replacement metal gate module needs controlled isotropic etch without damaging gate dielectric. SF6 based etch provides sharp N-P boundary and improved gate reliability.

  4. Optimization of “T”-Shaped Fins Geometry Using Constructal Theory and “FEA” Concepts

    Directory of Open Access Journals (Sweden)

    ManasRanjanPadhy

    2014-12-01

    Full Text Available This paper reports the geometric (constructal optimization of T-shaped fin assemblies, where the objective is to maximize the global thermal conductance of the assembly, subject to total volume and fin-material constraints. Assemblies of plate fins are considered. It is shown that every geometric feature of the assembly is delivered by the optimization principle and the constraints. These optimal features are reported in dimensionless terms for this entire class of fin assemblies. Based on the constructal theory by Dr. A Bejan, T-shaped fins are developed for better heat conductance as compared to conventional fins. Now the geometry of this T type of fin contains many geometry parameters which affect the overall conductance of the fin. With the same material constraint and volume constraints optimal geometry ratios has been calculated so as to design the fin for its best performance. With focus to the practical situations and heat flow patterns, it is quite complex to calculate the temperatures on a T-shaped fin. It requires the help of FEA concepts and CAE software to optimize the geometry.

  5. Correlated evolution of body and fin morphology in the cichlid fishes.

    Science.gov (United States)

    Feilich, Kara L

    2016-10-01

    Body and fin shapes are chief determinants of swimming performance in fishes. Different configurations of body and fin shapes can suit different locomotor specializations. The success of any configuration is dependent upon the hydrodynamic interactions between body and fins. Despite the importance of body-fin interactions for swimming, there are few data indicating whether body and fin configurations evolve in concert, or whether these structures vary independently. The cichlid fishes are a diverse family whose well-studied phylogenetic relationships make them ideal for the study of macroevolution of ecomorphology. This study measured body, and caudal and median fin morphology from radiographs of 131 cichlid genera, using morphometrics and phylogenetic comparative methods to determine whether these traits exhibit correlated evolution. Partial least squares canonical analysis revealed that body, caudal fin, dorsal fin, and anal fin shapes all exhibited strong correlated evolution consistent with locomotor ecomorphology. Major patterns included the evolution of deep body profiles with long fins, suggestive of maneuvering specialization; and the evolution of narrow, elongate caudal peduncles with concave tails, a combination that characterizes economical cruisers. These results demonstrate that body shape evolution does not occur independently of other traits, but among a suite of other morphological changes that augment locomotor specialization. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  6. The fin design for small-diameter tube and performance evaluation method

    Energy Technology Data Exchange (ETDEWEB)

    Fan, J.F.; Wu, Z.G.; He, Y.L.; Tao, W.Q. [Xi' an Jiaotong Univ., Xi' an (China). School of Energy and Power Engineering

    2010-07-01

    The heat transfer and friction characteristics of heat exchangers were investigated in order to improve the overall performance of heat exchangers, including a reduction in size and energy conservation. This paper proposed a simple but efficient performance comparison method based on the assumptions of constant properties and identical frontal area. An orthogonal design method proposed by Taguchi was used to reduce the number of computational cases, but still obtain nearly optimum combination of major geometric factors. The equations for constructing a plot for comparison of in-designing surface were derived and then the Taguchi method was used to find a nearly-optimum structure. A new slotted fin with tubes of 4 mm was then proposed to replace the original louvered fin with tubes of 7 mm. The reasonable parametric combination of global parameters was obtained by analyzing the numerical results of 16 plain plate fins. Three new slotted fins with different fin pitch were proposed. The slotted fin with fin pitch of 1.4 mm was recommended after considering the heat transfer, comprehensive performance, and cost of material and operation. The results showed that compared to the original louvered fin, the heat transfer rate of the recommended fin increased by 2.2, 22.5 and 13.7 per cent under identical flow rate, identical pressure drop and identical pumping power constraint, respectively. The new fin design also saved on the use of copper tubing material by about 36 per cent. 25 refs., 2 tabs., 10 figs.

  7. Thermal-hydraulic performance of novel louvered fin using flat tube cross-flow heat exchanger

    Institute of Scientific and Technical Information of China (English)

    Junqi DONG; Jiangping CHEN; Zhijiu CHEN

    2008-01-01

    Experimental studies were conducted to investigate the air-side heat transfer and pressure drop characteristics of a novel louvered fins and flat tube heat exchangers. A series of tests were conducted for 9 heat exchangers with different fin space and fin length, at a constant tube-side water flow rate of 2.8 m/h. The air side thermal performance data were analyzed using the effectiveness-NTU method. Results were presented as plot of Colburn j factor and friction factor f against the Reynolds number in the range of 500-6500. The characteristics of the heat transfer and pressure drop of different fin space and fin length were analyzed and compared. In addition, the curves of the heat transfer coefficients vs. pumping power per unit heat transfer area were plotted. Finally, the area optimization factor was used to evaluate the thermal hydraulic performance of the louvered fins with differential geometries. The results showed that the j and ffactors increase with the decrease of the fin space and fin length, and the fin space has more obvious effect on the thermal hydraulic characteristics of the novel louvered fins.

  8. Highly flexible SRAM cells based on novel tri-independent-gate FinFET

    Science.gov (United States)

    Liu, Chengsheng; Zheng, Fanglin; Sun, Yabin; Li, Xiaojin; Shi, Yanling

    2017-10-01

    In this paper, a novel tri-independent-gate (TIG) FinFET is proposed for highly flexible SRAM cells design. To mitigate the read-write conflict, two kinds of SRAM cells based on TIG FinFETs are designed, and high tradeoff are obtained between read stability and speed. Both cells can offer multi read operations for frequency requirement with single voltage supply. In the first TIG FinFET SRAM cell, the strength of single-fin access transistor (TIG FinFET) can be flexibly adjusted by selecting five different modes to meet the needs of dynamic frequency design. Compared to the previous double-independent-gate (DIG) FinFET SRAM cell, 12.16% shorter read delay can be achieved with only 1.62% read stability decrement. As for the second TIG FinFET SRAM cell, pass-gate feedback technology is applied and double-fin TIG FinFETs are used as access transistors to solve the severe write-ability degradation. Three modes exist to flexibly adjust read speed and stability, and 68.2% larger write margin and 51.7% shorter write delay are achieved at only the expense of 26.2% increase in leakage power, with the same layout area as conventional FinFET SRAM cell.

  9. Pectoral fin morphology of batoid fishes (Chondrichthyes: Batoidea): explaining phylogenetic variation with geometric morphometrics.

    Science.gov (United States)

    Franklin, Oliver; Palmer, Colin; Dyke, Gareth

    2014-10-01

    The diverse cartilaginous fish lineage, Batoidea (rays, skates, and allies), sister taxon to sharks, comprises a huge range of morphological diversity which to date remains unquantified and unexplained in terms of evolution or locomotor style. A recent molecular phylogeny has enabled us to confidently assess broadscale aspects of morphology across Batoidea. Geometric morphometrics quantifies the major aspects of shape variation, focusing on the enlarged pectoral fins which characterize batoids, to explore relationships between ancestry, locomotion and habitat. A database of 253 specimens, encompassing 60 of the 72 batoid genera, reveals that the majority of morphological variation across Batoidea is attributable to fin aspect-ratio and the chordwise location of fin apexes. Both aspect-ratio and apex location exhibit significant phylogenetic signal. Standardized independent linear contrast analysis reveals that fin aspect-ratio can predict locomotor style. This study provides the first evidence that low aspect-ratio fins are correlated with undulatory-style locomotion in batoids, whereas high aspect-ratio fins are correlated with oscillatory locomotion. We also show that it is phylogeny that determines locomotor style. In addition, body- and caudal fin-locomotors are shown to exhibit low aspect-ratio fins, whereas a pelagic lifestyle correlates with high aspect-ratio fins. These results emphasize the importance of phylogeny in determining batoid pectoral fin shape, however, interactions with other constraints, most notably locomotor style, are also highlighted as significant. © 2014 Wiley Periodicals, Inc.

  10. Heat transfer with phase change around finned cylindrical tubes: Theory and experiments

    Energy Technology Data Exchange (ETDEWEB)

    Kamal, A.; Alves, C.L.F.; Ismail, R.

    1983-12-01

    In order to increase the heat transfer rate and reduce the convective effects in latent heat storage tanks externally finned cylinderical tubes are used where the working fluid passes inside the tubes and the finned part submerged in the phase change material. A mathematical model is developed using the enthalpy approach and the numerical treatment is done using an ADI technique. Numerical results showing the effect of fin thickness, number of fins, length of fin and ratio of diameters of inner to outer tube are obtained, analysed and discussed. It is found that fin thickness has very little effect on the heat transfer rate. Number of fins, length of fin and ratio of inner to outer diameters are found to be great effect as can be verified from attached grafs. An experimental rig is designed, installed and instrumented in order to verify the theoretical findings and the validity of the model. Various cupper tubes models are used with Ecusan parrafin as phase change material. Models with 3, 4, 5 and 7 fins are used. Fins of various length are also used. Experimental results obtained are plotted to compare with the theoretical results. The agreements is found to be good, as shown in the grafs. It is found that the increase of number of fins leads and length of fin to suppressing convective currents and increase the heat transfer and solidification rates. The thickness and fin material are found to have very little effect on the heat transfer and solidification rates. In the mean time the ratio of diameters of the inner and the outer tubes is found to increase the heat transfer and solidification rates.

  11. Finned Carbon-Carbon Heat Pipe with Potassium Working Fluid

    Science.gov (United States)

    Juhasz, Albert J.

    2010-01-01

    This elemental space radiator heat pipe is designed to operate in the 700 to 875 K temperature range. It consists of a C-C (carbon-carbon) shell made from poly-acrylonitride fibers that are woven in an angle interlock pattern and densified with pitch at high process temperature with integrally woven fins. The fins are 2.5 cm long and 1 mm thick, and provide an extended radiating surface at the colder condenser section of the heat pipe. The weave pattern features a continuous fiber bath from the inner tube surface to the outside edges of the fins to maximize the thermal conductance, and to thus minimize the temperature drop at the condenser end. The heat pipe and radiator element together are less than one-third the mass of conventional heat pipes of the same heat rejection surface area. To prevent the molten potassium working fluid from eroding the C C heat pipe wall, the shell is lined with a thin-walled, metallic tube liner (Nb-1 wt.% Zr), which is an integral part of a hermetic metal subassembly which is furnace-brazed to the inner surface of the C-C tube. The hermetic metal liner subassembly includes end caps and fill tubes fabricated from the same Nb-1Zr alloy. A combination of laser and electron beam methods is used to weld the end caps and fill tubes. A tungsten/inert gas weld seals the fill tubes after cleaning and charging the heat pipes with potassium. The external section of this liner, which was formed by a "Uniscan" rolling process, transitions to a larger wall thickness. This section, which protrudes beyond the C-C shell, constitutes the "evaporator" part of the heat pipe, while the section inside the shell constitutes the condenser of the heat pipe (see figure).

  12. Multiphysics Numerical Modeling of a Fin and Tube Heat Exchanger

    DEFF Research Database (Denmark)

    Singh, Shobhana; Sørensen, Kim; Condra, Thomas Joseph

    2015-01-01

    ). For the purposes here, only gas flowing over the fin side is simulated assuming constant inner tube wall temperature. The study couples conjugate heat transfer mechanism with turbulent flow in order to describe the temperature and velocity profile. In addition, performance characteristics of the heat exchanger...... design in terms of heat transfer and pressure loss are determined by parameters such as overall heat transfer coefficient, Colburn j-factor, flow resistance factor, and efficiency index. The model provides useful insights necessary for optimization of heat exchanger design....

  13. Laser Welding Of Finned Tubes Made Of Austenitic Steels

    OpenAIRE

    Stolecki M.; Bijok H.; Kowal Ł.; Adamiec J.

    2015-01-01

    This paper describes the technology of welding of finned tubes made of the X5CrNi1810 (1.4301) austenitic steel, developed at Energoinstal SA, allowing one to get high quality joints that meet the requirements of the classification societies (PN-EN 15614), and at the same time to significantly reduce the manufacturing costs. The authors described an automatic technological line equipped with a Trumph disc laser and a tube production technological process. To assess the quality of the joints, ...

  14. Detailed analysis of fin-and-tube evaporators

    OpenAIRE

    2009-01-01

    This paper is devoted to the presentation of a new model for fin-and-tube evaporators, focusing on the solid core simulation and its integration with a quasi-homogeneous two-phase flow model for the in-tube refrigerant flow. Special attention is dedicated to separated in-tube flow patterns (stratified, stratified-wavy), because of their importance in liquid overfeed evaporators and the impact on the solid core temperature distribution. The paper presents the solid core formulation and nume...

  15. Coning motion stability of wrap around fin rockets

    Institute of Scientific and Technical Information of China (English)

    MAO XueRui; YANG ShuXing; XU Yong

    2007-01-01

    Both the asymptotical stability criterion and the bounded stability criterion of the coning motion for wrap around fin (WAF) rockets are proposed through the analysis of coning motion equations, which can be easily used to determine the existence of the coning motion during the rocket design. The correctness of the criterions is verified by mathematical simulation examples of a WAF rocket with different setting angles. It is also found that the setting angle of WAF has great effects on the rolling moment and side moment of the rocket.

  16. Coning motion stability of wrap around fin rockets

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Both the asymptotical stability criterion and the bounded stability criterion of the coning motion for wrap around fin(WAF) rockets are proposed through the analy-sis of coning motion equations,which can be easily used to determine the exis-tence of the coning motion during the rocket design. The correctness of the crite-rions is verified by mathematical simulation examples of a WAF rocket with differ-ent setting angles. It is also found that the setting angle of WAF has great effects on the rolling moment and side moment of the rocket.

  17. SICOMPC: SIMULADOR PARA CONTROL PREDICTIVO BASADO EN MODELOS

    Directory of Open Access Journals (Sweden)

    ROBIN SALCEDO

    2008-01-01

    Full Text Available En este artículo se describe la herramienta computacional SICOMPC desarrollada con el fin de poder disponer de un programa para simulación de control predictivo basado en modelos. Si bien existen en el mercado algunos programas dedicados al control predictivo, ellos son en su mayoría costosos y de estructuracerrada. SICOMPC de otro lado tiene una estructura modular e incluye además ventanas donde se puede simular las estrategias clásicas de control, con el fin de compararlas bajo criterios de estabilidad y robustez en diversos modelos de plantas de procesos.

  18. Tintas Ink-Jet para Decoracion 3D

    OpenAIRE

    Ferro Spain, S. A.

    2011-01-01

    Se han desarrollado un conjunto de diferentes tintas ink-jet, para aplicar como objeto 3D y capas extrafinas con el fin de proteger la decoración realizada mediante tecnología ink-jet. Estas nuevas tintas se obtienen a través del desarrollo de nuevas fritas basadas en estructuras vitro cristalinas monofásicas que permiten obtener efectos cerámicos mediante decoración digital. Las nuevas tintas mejoran la capacidad de aplicación mediante cabezales ink-jet con el fin de conseguir efect...

  19. Actitud Positiva: la base para la competitividad

    Directory of Open Access Journals (Sweden)

    Marco Anderson Espinoza

    2008-04-01

    Full Text Available Una estrategia empresarial enfocado en el mejoramiento continuo de la productividad para la competitividad, depende significativamente del manejo inteligente de tres variables visibles:Calidad, Entrega oportuna y Costo. No obstante, estas tres variables no suelen sersuficientes. La estrategia debe ser complementada con el manejo adecuado de variables intangibles como la Motivación y las Condiciones de Trabajo, con la aplicación de Tecnología Ambientalmente Amigable, en un marco de Actitud Positiva.A final de cuentas, la Actitud Positiva es fundamental para el recurso humano de cualquier organización, a fin de construir una plataforma sólida y estable que sirva de base para soportar un proceso sostenible de mejoramiento de la productividad, para aumentar la competitividad como estrategia empresarial exitosa.

  20. Intefaz gráfica para simulación de convertidores DC/AC para entorno docente

    OpenAIRE

    Cabeza Picazo, Josua

    2015-01-01

    En este Trabajo Fin de Grado se ha realizado un sistema software de simulación de inversores de potencia para uso docente. El proyecto ha sido desarrollado mediante Simulink y GUIDE, ambas herramientas de Matlab, creando una interfaz gráfica sencilla y didáctica. La aplicación permite la simulación de las diferentes tipologías de inversor estudiadas en distintas asignaturas relacionadas con la electrónica de potencia. En este Trabajo Fin de Grado se han estudiado diferentes técnicas de ...

  1. El cine a las puertas del siglo XXI: las imágenes apocalípticas del fin del mundo

    Directory of Open Access Journals (Sweden)

    Lic. Montse Hormigos Vaquero

    1998-01-01

    Full Text Available Se acerca el año 2000: el 'fin del mundo'. Una gran cantidad de profecías así lo recogen y a lo largo de muchos años se nos ha bombardeado con esta posibilidad de desaparición de la especie humana, tanto a través de medios escritos como audiovisuales. En la actualidad, se crean sectas que se preparan para el final, la televisión emite programas sobre desastres de diferente envergadura que potencian el desasosiego general, las publicaciones realizan encuestas del tipo: ¿cómo cree usted que va a llegar el fin del mundo?, mientras las revistas especializadas publican estudios sobre la validez científica de esas creencias.

  2. Numerical Analysis for Optimal Design of Fin and Tube Type Adsorber

    Science.gov (United States)

    Kariya, Keishi; Kuwahara, Ken; Shigeru, Koyama

    Adsorption cooling systems driven by low temperature waste heat (below 100°C) or renewable energy sources have gained considerable attention as one of the solutions for both energy and environment related problems. In this study, a two dimensional numerical analysis is carried out to evaluate the adsorption characteristics and to determine the performance of a fin and tube type adsorber/desorber heat exchanger; activated carbon fiber (ACF) of type A-20, which has relatively higher surface area, and ethanol are used as adsorbent/refrigerant pair. The effects of heat exchanger design configurations such as fin height, fin thickness, fin pitch, tube diameter and apparent density of ACF bed on the performance are examined numerically. The simulation results show that the cooling capacity can be optimized in the condition of fin height 15mm and fin pitch 5.5mm when other parameters are fixed.

  3. A Prediction Model for Condensation on Single Horizontal Rectangular Fin Tube

    Institute of Scientific and Technical Information of China (English)

    LiuXijuan; MaTongze; 等

    1997-01-01

    A model was established to predict condensation heat transfer coefficient on horizontal rectangularfinned tube.Drop-Off zone at the tube bottom was considered and determined,the known Honda (and Owen) expression of retention angle was also modified as a result of considering drop-off zone.Heat flux on fin tips in the unflooded region,fin flanks,fin spacings and fin tips in the flooded region were analyzed respectively.COndensation on fin tips in emphasized by considering the variation of film thickness along circumference as well as horizontally.FIn efficiency was considered in calculation.The prediction results were compared with several researchers' experimental data for three kinds of working fluids on seven different tube geometries and for various temperature differences,These data under about 60 test conditions were predicted with discrepancy of ±10% .Prediction by the present model for steam and R-113 condensation were compared with previous models.

  4. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Energy Technology Data Exchange (ETDEWEB)

    Reid, D.R. (FINTUBE Corp., Tulsa, OK (United States)); Taborek, J. (Taborek (J.), Virginia Beach, VA (United States))

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded plain'' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of segmented'' fins. The main advantage of this fin design (Fig. 1) is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  5. Selection criteria for plain and segmented finned tubes for heat recovery systems

    Science.gov (United States)

    Reid, D. R.; Taborek, J.

    1994-04-01

    Heat recovery heat exchangers with gas as one of the streams depend on the use of finned tubes to compensate for the inherently low gas heat transfer coefficient. Standard frequency welded 'plain' fins were generally used in the past, until the high-frequency resistance welding technology permitted a cost-effective manufacture of 'segmented' fins. The main advantage of this fin design is that it permits higher heat flux and hence smaller, lighter weight units for most operating conditions. While the criteria that dictate optimum design, such as compactness, weight, and cost per unit area favor the segmented fin design, a few other considerations such as fouling, ease of cleaning, and availability of dependable design methods have to be considered. This paper analyzes the performance parameters that affect the selection of either fin type.

  6. Mechanism of tonal noise generation from circular cylinder with spiral fin

    Science.gov (United States)

    Yamashita, Ryo; Hayashi, Hidechito; Okumura, Tetsuya; Hamakawa, Hiromitsu

    2014-12-01

    The pitch of the spiral finned tube influences seriously to the acoustic resonance in the heat exchanger. In this research, the flow characteristics in relating to the aeolian tone from the finned cylinder are studied by the numerical simulation. It is observed that the tonal noise generated from the finned tube at two pitch spaces. The ratio of the fin pitch to the cylinder diameter is changed at 0.11 and 0.27. The tone level increases and the frequency decreases with the pitch shorter. The separation flow from the cylinder generates the span-wise vortices, Karman vortices, and the separation flow from the fin generates the stream-wise vortices. When the fin pitch ratio is small, the stream-wise vortices line up to span-wise and become weak rapidly. Only the Karman vortices are remained and integrate in span. So the Karman vortex became large. This causes the low frequency and the large aeolian tone.

  7. Thermal performance of functionally graded parabolic annular fins having constant weight

    Energy Technology Data Exchange (ETDEWEB)

    Gaba, Vivek Kumar; Tiwari, Anil Kumar; Bhowmick, Shubhankar [National Institute of Technology Raipur, Raipur (India)

    2014-10-15

    The proposed work reports the performance of parabolic annular fins of constant weight made of functionally graded materials. The work involves computation of temperature gradient, efficiency and effectiveness of such fins and compares the performances for different functionally graded parabolic fin profiles obtained by varying grading parameters and profile parameters respectively keeping the weight of the fins constant. The functional grading of thermal conductivity is based on a power function of radial co-ordinate which consists of parameters, namely grading parameters, varying which different grading combinations are studied. A general second order ordinary differential equation has been derived for all the profiles and material grading. The efficiency and effectiveness of the annular fins of different profile and grading combinations have been calculated and plotted and the results reveal the dependence of fin performance on profile and grading parameter.

  8. Parametric study on the performance of a heat exchanger with corrugated louvered fins

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Zhao-gang; Chen, Jiang-ping; Chen, Zhi-jiu [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, No. 1954, Huashan Rd., Shanghai 200030 (China)

    2007-02-15

    The Taguchi method is a well-known parametric study tool in engineering quality and experimental design. This study analyzes five experimental factors (flow depth, ratio of fin pitch and fin thickness, tube pitch, number of louvers and angle of louver) affecting the heat transfer and pressure drop of a heat exchanger with corrugated louvered fins using the Taguchi method. Fifteen samples are selected from experimental database and the heat transfer and flow friction characteristics are analyzed. The results show that flow depth, ratio of fin pitch and fin thickness and the number of the louvers are the main factors that influence significantly the thermal hydraulic performance of the heat exchanger with corrugated louvered fins. Therefore, these three factors are considered as the main factors for an optimum design of a heat exchanger. (author)

  9. Numerical Study of Liner Modification Methods Leading to Fin-stabilized Explosively Formed Penetrators

    Science.gov (United States)

    Asmolovskiy, Nikolay; Baskakov, Vladimir

    2013-06-01

    One of the methods of increasing aerodynamic properties of elongated explosively formed penetrators (EFP) is inducing fins in the rear part of the projectile. In this work a set of fins generation methods was examined. Analysis showed that small amplitude wave-shaped imperfections in circumferential area of the liner provide projectile with desired finned shape without significant changes in formation process, which can reduce development cycle compared to axisymmetric EFP. Three methods of fins generation based on imperfections induced in liner were simulated numerically using commercial software. Suitable simulation technique was chosen and modified in order to treat geometrical imperfections of small amplitudes without large computational efforts. The relation between imperfection amplitude and projectile shape was obtained. It was shown that periodic nonuniform thickness is effective method of fins generation. For example, imperfection amplitude of 2% leads to fins with amplitude 10%. Material damage properties were taken into account and yielded range of acceptable imperfection amplitude.

  10. Synchronized swimming: coordination of pelvic and pectoral fins during augmented punting by the freshwater stingray Potamotrygon orbignyi.

    Science.gov (United States)

    Macesic, Laura J; Mulvaney, Dana; Blevins, Erin L

    2013-06-01

    Benthic animals live at the juncture of fluid and solid environments, an interface that shapes many aspects of their behavior, including their means of locomotion. Aquatic walking and similar substrate-dependent forms of underwater propulsion have evolved multiple times in benthic invertebrate and vertebrate taxa, including batoid elasmobranchs. Skates (Rajidae) use the pelvic fins to punt across the substrate, keeping the pectoral fin disc still. Other batoids combine pelvic fin motions with pectoral fin undulation in augmented punting, but the coordination of these two modes has not been described. In this study of an augmented punter, the freshwater stingray Potamotrygon orbignyi, we demonstrate the synchrony of pelvic and pectoral fin cycles. The punt begins as the pelvic fins, held in an anterior position, are planted into the substrate and used to push the body forward. Meanwhile, a wave of pectoral fin undulation begins, increasing to maximum height just before the cycle's halfway point, when the pelvic fins reach their furthest posterior extension. The pectoral fin wave subsides as the pelvic fins return to their starting position for subsequent punts. Despite definitive links between pectoral and pelvic fin activity, we find no significant relationship between pectoral fin kinematics (frequency, wave height, and wave speed) and punt performance. However, slip calculations indicate that pectoral undulation can produce thrust and augment punting. Pelvic fin kinematics (frequency and duty factor) have significant effects, suggesting that while both sets of fins contribute to thrust generation, the pelvic fins likely determine punt performance.

  11. Conjugated laminar forced convective heat transfer from internally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wen-Quan Tao (Xi' an Jiaotong Univ., Shaanxi (China))

    1987-08-01

    The use of internal fins is a very effective means of augmenting heat transfer in a tubular heat exchanger, especially for the laminar flow case. Several theoretical investigations have been undertaken to determine heat transfer performance under fully developed conditions. Results reported in the literature are derived for prescribed thermal boundary conditions, wither with axially uniform heat flux with peripherally uniform temperature, or with constant temperature axially as well as circumferentially. However, for double pipe heat exchangers, the thermal boundary condition of the separating wall can not be prescribed a priori; it is determined by the thermal interaction between the fluid inside the tube and that in the annular space. Mikhailov and Shishedjiev (1981), and Tao (1986) have shown that Nusselt number of the tube and that of the annular are strongly dependent upon the heat capacity ratio of the two fluids. In this investigation, a performance analysis is conducted numerically for an internally finned tube which serves as the inner tube of a double pipe heat exchanger.

  12. FinFET and UTBB for RF SOI communication systems

    Science.gov (United States)

    Raskin, Jean-Pierre

    2016-11-01

    Performance of RF integrated circuit (IC) is directly linked to the analog and high frequency characteristics of the transistors, the quality of the back-end of line process as well as the electromagnetic properties of the substrate. Thanks to the introduction of the trap-rich high-resistivity Silicon-on-Insulator (SOI) substrate on the market, the ICs requirements in term of linearity are fulfilled. Today partially depleted SOI MOSFET is the mainstream technology for RF SOI systems. Future generations of mobile communication systems will require transistors with better high frequency performance at lower power consumption. The advanced MOS transistors in competition are FinFET and Ultra Thin Body and Buried oxide (UTBB) SOI MOSFETs. Both devices have been intensively studied these last years. Most of the reported data concern their digital performance. In this paper, their analog/RF behavior is described and compared. Both show similar characteristics in terms of transconductance, Early voltage, voltage gain, self-heating issue but UTBB outperforms FinFET in terms of cutoff frequencies thanks to their relatively lower fringing parasitic capacitances.

  13. Fgf signalling controls diverse aspects of fin regeneration.

    Science.gov (United States)

    Shibata, Eri; Yokota, Yuki; Horita, Natsumi; Kudo, Akira; Abe, Gembu; Kawakami, Koichi; Kawakami, Atsushi

    2016-08-15

    Studies have shown that fibroblast growth factor (Fgf) signalling is necessary for appendage regeneration, but its exact function and the ligands involved during regeneration have not yet been elucidated. Here, we performed comprehensive expression analyses and identified fgf20a and fgf3/10a as major Fgf ligands in the wound epidermis and blastema, respectively. To reveal the target cells and processes of Fgf signalling, we performed a transplantation experiment of mesenchymal cells that express the dominant-negative Fgf receptor 1 (dnfgfr1) under control of the heat-shock promoter. This mosaic knockdown analysis suggested that Fgf signalling is directly required for fin ray mesenchyme to form the blastema at the early pre-blastema stage and to activate the regenerative cell proliferation at a later post-blastema stage. These results raised the possibility that the early epidermal Fgf20a and the later blastemal Fgf3/10a could be responsible for these respective processes. We demonstrated by gain-of-function analyses that Fgf20a induces the expression of distal blastema marker junbl, and that Fgf3 promotes blastema cell proliferation. Our study highlights that Fgfs in the wound epidermis and blastema have distinct functions to regulate fin regeneration cooperatively.

  14. Implication of type 3 deiodinase induction in zebrafish fin regeneration.

    Science.gov (United States)

    Bouzaffour, Mohamed; Rampon, Christine; Ramaugé, Martine; Courtin, Françoise; Vriz, Sophie

    2010-08-01

    Thyroid hormones are critical determinants of cellular differentiation. We used the zebrafish model to evaluate the involvement of thyroid hormones in regeneration processes after caudal fin amputation. We examined early events following fin amputation, i.e., blastema formation and nerve repair by growth cone formation. Here, we show that the abolition of thyroid gland activity by methimazole treatment had no effect on blastema formation, but slowed growth cone formation of the lateral line. Conversely, the addition of exogenous thyroid hormones enhanced growth cone formation without affecting blastema formation. However, amputation triggered a strong induction in the blastema of type 3 deiodinase mRNA and enzymatic activity, which degrades thyroid hormone (TH). We therefore blocked deiodinase activity with iopanoic acid (IOP) and saw a reduction in blastema formation, suggesting that local degradation of TH is permissive for cell proliferation in the blastema. The effect of IOP on the blastema required endogenous or exogenous TH. Our findings support a model in which local degradation of TH by type 3 deiodinase is permissive for epimorphic regeneration.

  15. Fgf and Sdf-1 pathways interact during zebrafish fin regeneration.

    Science.gov (United States)

    Bouzaffour, Mohamed; Dufourcq, Pascale; Lecaudey, Virginie; Haas, Petra; Vriz, Sophie

    2009-06-08

    The chemokine stromal cell-derived factor-1 (SDF1) was originally identified as a pre-B cell stimulatory factor but has been recently implicated in several other key steps in differentiation and morphogenesis. In addition, SDF1 as well as FGF signalling pathways have recently been shown to be involved in the control of epimorphic regeneration. In this report, we address the question of a possible interaction between the two signalling pathways during adult fin regeneration in zebrafish. Using a combination of pharmaceutical and genetic tools, we show that during epimorphic regeneration, expression of sdf1, as well as of its cognate receptors, cxcr4a, cxcr4b and cxcr7 are controlled by FGF signalling. We further show that, Sdf1a negatively regulates the expression of fgf20a. Together, these results lead us to propose that: 1) the function of Fgf in blastema formation is, at least in part, relayed by the chemokine Sdf1a, and that 2) Sdf1 exerts negative feedback on the Fgf pathway, which contributes to a transient expression of Fgf20a downstream genes at the beginning of regeneration. However this feedback control can be bypassed since the Sdf1 null mutants regenerate their fin, though slower. Very few mutants for the regeneration process were isolated so far, illustrating the difficulty in identifying genes that are indispensable for regeneration. This observation supports the idea that the regeneration process involves a delicate balance between multiple pathways.

  16. Fgf and Sdf-1 pathways interact during zebrafish fin regeneration.

    Directory of Open Access Journals (Sweden)

    Mohamed Bouzaffour

    Full Text Available The chemokine stromal cell-derived factor-1 (SDF1 was originally identified as a pre-B cell stimulatory factor but has been recently implicated in several other key steps in differentiation and morphogenesis. In addition, SDF1 as well as FGF signalling pathways have recently been shown to be involved in the control of epimorphic regeneration. In this report, we address the question of a possible interaction between the two signalling pathways during adult fin regeneration in zebrafish. Using a combination of pharmaceutical and genetic tools, we show that during epimorphic regeneration, expression of sdf1, as well as of its cognate receptors, cxcr4a, cxcr4b and cxcr7 are controlled by FGF signalling. We further show that, Sdf1a negatively regulates the expression of fgf20a. Together, these results lead us to propose that: 1 the function of Fgf in blastema formation is, at least in part, relayed by the chemokine Sdf1a, and that 2 Sdf1 exerts negative feedback on the Fgf pathway, which contributes to a transient expression of Fgf20a downstream genes at the beginning of regeneration. However this feedback control can be bypassed since the Sdf1 null mutants regenerate their fin, though slower. Very few mutants for the regeneration process were isolated so far, illustrating the difficulty in identifying genes that are indispensable for regeneration. This observation supports the idea that the regeneration process involves a delicate balance between multiple pathways.

  17. Condensation heat transfer on finned tubes with radial ridges on the fin surfaces. 2nd Report. ; Theoretical study. Hankei hoko ni tokki wo motsu shuhoko fin ni yoru gyoshuku netsu dentatsu sokushin. 2. ; Rironteki kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    Hijikata, K.; Nakabeppu, O. (Tokyo Inst. of Technology, Tokyo (Japan)); Wang, P.

    1991-05-25

    A model of finned tubes is developed to predict condensation performance of R-tubes with radial ridges circumferential fin surfaces. Results predicted by this model make an accurate explanation of experimental data, and the condensation mechanism of R-tubes and freon {prime} s condensation heat transfer to R-tubes are predicted by the model R-tubes have high condensation heat transfer coefficients because the ridges on the fin surfaces of the R-tube extend the thin condensate film area and also promote convective heat transfer in the film. In condensation of high performance finned tubes, load values like local temperature differences, local heat flux, local heat transfer coefficient change circumferentially. Therefore, it is necessary to consider this change using theoretical models. 17 refs., 9 figs.

  18. Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

    OpenAIRE

    Novi Andria

    2013-01-01

    Flutter is a phenomenon that has brought a catastrophic failure to the flight vehicle structure. In this experiment, flutter was analyzed for its symmetric and antisymmetric configuration to understand the effect of rocket rigid modes to the fin flutter characteristic. This research was also expected to find out the safety level of RX-420 structure design. The analysis was performed using half rocket model. Fin structure used in this research was a fin which has semispan 600 mm, thickness 12 ...

  19. Simulation study of a 3-D device integrating FinFET and UTBFET

    KAUST Repository

    Fahad, Hossain M.

    2015-01-01

    By integrating 3-D nonplanar fins and 2-D ultrathin bodies, wavy FinFETs merge two formerly competing technologies on a silicon-on-insulator platform to deliver enhanced transistor performance compared with conventional trigate FinFETs with unprecedented levels of chip-area efficiency. This makes it suitable for ultralarge-scale integration high-performance logic at and beyond the 10-nm technology node.

  20. Flow structure of natural dehumidification over a horizontal finned-tube

    Science.gov (United States)

    Hirbodi, Kamran; Yaghoubi, Mahmood

    2016-08-01

    In the present study, structure of water drops formation, growth, coalescence and departure over a horizontal finned-tube during natural dehumidification is investigated experimentally. Starting time of repelling the drops as well as heat transfer rate and the rate of dripping condensates in quasi-steady-state conditions are presented. Furthermore, cold airflow pattern around the horizontal finned-tube is visualized by using smoke generation scheme during natural dehumidification process. The finned-tube has a length of 300 mm, and inner and outer fin diameters, fin thickness and fin spacing are 25.4, 56, 0.4 and 2 mm, respectively. The tests are conducted in an insulated control room with dimensions of 5.8 m × 3 m × 4 m. Ambient air temperature, relative humidity and fin base temperature are selected from 25 to 35 °C, from 40 to 70 % and from 4 to 8 °C, respectively. Observations show that natural condensation from humid air over the test case is completely dropwise. Droplets only form on the edge of the fin and lateral fin surfaces remain almost dry. Dehumidification process over the tested finned-tube is divided into four stages; nucleation, formation, growth and departure of drops. It is also observed that the condensate inundation leaves the tube bottom in the form of droplets. Smoke visualization depicts that humid airflows downward around the cold finned-tube surface without noticeable turbulence and separation in the initial stages of dehumidification process. But the airflow has some disturbances in the intermediate stage and especially during drop departure on the edge of the fins.

  1. Efficient heat-transfer surfaces assembled from partially finned flat-oval tubes

    Science.gov (United States)

    Pis'mennyi, E. N.

    2011-04-01

    The state of finned convective heat-transfer surfaces and prospects for using them in power engineering and industry are briefly reviewed. The characteristics of a heat-recovery economizer made of partially finned flat-oval tubes are presented by way of comparing them with design versions employing known types of finned tubes, and the results gained from its operation downstream of a PTVM-30M boiler are given.

  2. 3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

    OpenAIRE

    2015-01-01

    The use of 3-D computational fluid dynamics (CFD) is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, th...

  3. Molecular Signaling Networks That Choreograph Epimorphic Fin Regeneration in Zebrafish – A Mini-Review

    OpenAIRE

    Tal, Tamara L; Franzosa, Jill A.; Tanguay, Robert L.

    2009-01-01

    This short review provides a current synopsis of caudal fin regeneration in zebrafish with an emphasis on the molecular signaling networks that dictate epimorphic regeneration. At the outset, the fundamentals of caudal fin architecture and the stages of epimorphic regeneration are described. This is followed by a detailed look at the main networks implicated in fin regeneration, namely the Wnt, fibroblast growth factor, activin-βA, retinoic acid and hedgehog signaling pathways. Throughout thi...

  4. Investigation of Fish Caudal Fin Locomotion Using a Bio-inspired Robotic Model

    OpenAIRE

    Ziyu Ren; Kainan Hu; Tianmiao Wang; Li Wen

    2016-01-01

    Due to its advantages of realizing repeatable experiments, collecting data and isolating key factors, the bio-robotic model is becoming increasingly important in the study of biomechanics. The caudal fin of fish has long been understood to be central to propulsion performance, yet its contribution to manoeuverability, especially for homocercal caudal fin, has not been studied in depth. In the research outlined in this paper, we designed and fabricated a robotic caudal fin to mimic the morphol...

  5. Thermal performance of a porus radial fin with natural convection and radiative heat losses

    Directory of Open Access Journals (Sweden)

    Darvishi M.T.

    2015-01-01

    Full Text Available An analytic (series solution is developed to describe the thermal performance of a porous radial fin with natural convection in the fluid saturating the fin and radiation heat loss from the top and bottom surfaces of the fin. The HAM results for the temperature distribution and base heat flux are compared with the direct numerical results and found to be very accurate.

  6. Experimental investigation of wing fin configurations for alleviation of vortex wakes of aircraft

    Science.gov (United States)

    Rossow, V. J.

    1978-01-01

    A variety of fin configurations were tested on a model of the Boeing B747 in 40 by 80 foot wind tunnels. The test results confirmed that a reduction in wake rolling moment was brought about by the vortex shed by the fins so that a wide range of designs can be used to achieve wake alleviation. It was also found that the reduction in wake-induced rolling moments was especially sensitive to the location of the smaller fins on the wing and that the penalties in lift and drag can probably be made negligible by proper fin design.

  7. DETERMINATION OF TEMPERATURE DISTRIBUTION FOR ANNULAR FINS WITH TEMPERATURE DEPENDENT THERMAL CONDUCTIVITY BY HPM

    Directory of Open Access Journals (Sweden)

    Davood Domairry Ganji

    2011-01-01

    Full Text Available In this paper, homotopy perturbation method has been used to evaluate the temperature distribution of annular fin with temperature-dependent thermal conductivity and to determine the temperature distribution within the fin. This method is useful and practical for solving the nonlinear heat transfer equation, which is associated with variable thermal conductivity condition. The homotopy perturbation method provides an approximate analytical solution in the form of an infinite power series. The annular fin heat transfer rate with temperature-dependent thermal conductivity has been obtained as a function of thermo-geometric fin parameter and the thermal conductivity parameter describing the variation of the thermal conductivity.

  8. Heat transfer, erosion and acid condensation characteristics for novel H-type finned oval tube

    Science.gov (United States)

    Wang, Y.; Zhao, X.; Tang, G.

    2015-09-01

    Low efficiency of heat transfer, acid corrosion and erosion of economizers affect the economy and security in coal-fired power plants significantly. The H-type finned oval tube is proposed to alleviate these problems. Based on the H-type finned oval tube, we investigated three novel types of fins, including bleeding dimples, longitudinal vortex generators (LVGs), and compound dimple-LVG. We considered the three aspects together, and obtained the heat transfer, acid condensation rate and erosion loss. The results show that the tube bank with the new structured fins can improve the performance on the three aspects, and the compound dimple-LVG performs the highest comprehensive effect.

  9. Film condensation of R-113 on in-line bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H. (Kyushu Univ., Fukuoka (Japan)); Uchima, B.; Nozu, S.; Nakata, H.; Torigoe, E. (Okayama Univ. (Japan))

    1991-05-01

    Film condensation of R-113 on in-line bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The test sections were 3 {times} 15 tube bundles with and without two rows of inundation tubes at the top. Heat transfer measurements were carried out on a row-by-row basis. The heat transfer enhancement due to vapor shear was much less for a finned tube bundle than for a smooth tube bundle. The decrease in heat transfer due to condensate inundation was more marked for a three-dimensional fin tube than for a flat-sided fin tube. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed well with the measured data for low vapor velocity and a small to medium condensate inundation rate. Among the six tubes tested, the highest heat transfer performance was provided by the flat-sided fin tube with fin dimensions close to the theoretically determined optimum values.

  10. Numerical prediction of laminar flow and heat transfer in internally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Rustum, I.M.

    1990-02-01

    An investigation was carried out to provide a detailed analysis of laminar fluid flow and heat transfer in internally finned pipes. Three mathematical models were formulated for this purpose, and shown to be capable of simulating the actual situation of pressure drop and heat transfer in such tubes. Steady, laminar forced convection heat transfer in the thermal entrance region of internally finned tubes was investigated numerically for the case of fully developed hydrodynamics using the H1 and T thermal boundary conditions. Steady, laminar fluid flow in the hydrodynamic entrance region of internally finned tubes was investigated numerically. Results are presented for the smooth tube geometry and sixteen geometries corresponding to various combinations of relative fin heights and number of fins. Steady, laminar mixed convection in the fully developed region of horizontal internally finned tubes was investigated for the case of uniform heat input axially and uniform wall temperature circumferentially. Fluid flow and heat transfer characteristics were found to be dependent on a modified Grashof number, Prandtl number, relative fin height, and number of fins. Internal finning was found to retard the onset of significant free convective effects and to suppress the enhancement in friction factor and Nusselt number compared to smooth tubes. 54 refs., 93 figs., 12 tabs.

  11. Ultra Low Power 14XM FinFET's Process-a Radical New Approach to Transistors

    Directory of Open Access Journals (Sweden)

    Suhas K. V.

    2013-05-01

    Full Text Available FinFET technology is a radical new technology that has been proposed by the industry to overcome large leakage power occurring in low power VLSI circuits. In this paper, the working of the basic MOSFET, condition of operations for any transistor and the FinFET along with its structure is described. This paper mainly covers how FinFET can be an advantage compared to basic MOSFET and how leakage can be reduced in FinFET is explained with the comparison of basic MOSFET. The fabrication steps are briefly discussed

  12. Numerical simulation and experimental research of a flexible caudal fin by piezoelectric fiber composite

    Directory of Open Access Journals (Sweden)

    Yuan-Lin Guan

    2015-07-01

    Full Text Available A flexible caudal fin made of the macro fiber composites and the carbon fiber orthotropic composite was investigated by the numerical simulations and the experiments. First, a three-dimensional numerical simulation procedure was adopted to research the torsion propulsion mode of the caudal fin and the impact of the water for the structural torsion frequency of the caudal fin. Then, a two-dimensional unsteady fluid computational method was used to analyze the hydrodynamic performance with the periodic swing of the caudal fin on the torsion mode. Based on the simulation results, the flow field was demonstrated and discussed. The interaction between the caudal fin and the water was explained. Finally, the laser vibrometer system was built to verify the torsion propulsion mode. Meanwhile, the application of the caudal fin was realized on the torsion propulsion, and the measured system was established to demonstrate the performance of the caudal fin. The established simulation procedures and experimental methods in this study may provide guidance to the fins made of the composite materials during the structural design and the investigation of the flow field characteristics with the movement of the fins.

  13. Comprehensive performance comparison of airfoil fin PCHEs with NACA 00XX series airfoil

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Fei, E-mail: chenfei@iet.cn [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Heating Technology Research and Development Center, Beijing District Heating Group, Beijing 100028 (China); Zhang, Lishen, E-mail: lishenzhang@sina.com [Heating Technology Research and Development Center, Beijing District Heating Group, Beijing 100028 (China); Huai, Xiulan, E-mail: hxl@iet.cn [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Li, Jufeng, E-mail: lijufeng.net@163.com [Nuclear and Radiation Safety Center, Ministry of Environmental Protection, Beijing 100082 (China); Zhang, Hang, E-mail: zhanghang@iet.cn [Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, Zhigang, E-mail: zgliu9322@163.com [Energy Research Institute of Shandong Academy of Sciences, Jinan, Shandong 250014 (China)

    2017-04-15

    Highlights: • Pressure drop of NACA 0020 airfoil fin PCHE reduces strikingly in comparison with the zigzag PCHE. • Pressure drop of NACA 00XX airfoil fin PCHE decreases as airfoil thickness increases. • Heat transfer performance of NACA 00XX airfoil fin PCHE increases as airfoil thickness rises. • Comprehensive performance of NACA 00XX airfoil fin PCHE degrades as airfoil thickness increases. - Abstract: Printed circuit heat exchanger (PCHE) can be used in supercritical carbon dioxide (S-CO{sub 2}) Brayton cycle. The present study compares NACA 0020 airfoil fin PCHE with conventional zigzag PCHE by numerical analysis. Pressure drop of the former has a striking reduction while maintaining excellent heat transfer performance. Comparison on four NACA 00XX series airfoil fin PCHEs is performed to investigate the influence of airfoil profile on flow and heat transfer performance. With a fixed vertical pitch, heat transfer performance of NACA series airfoil fin PCHE increases as airfoil thickness increases. However, comprehensive performance, in which both flow and heat transfer are taken into account, degrades with increasing airfoil thickness. Among four NACA airfoil fin PCHEs presented in this paper, NACA 0010 airfoil fin PCHE demonstrates the best comprehensive performance.

  14. Fin-Body Interaction and its Hydrodynamic Benefits in Fish's Steady Swimming

    Science.gov (United States)

    Liu, Geng; Ren, Yan; Dong, Haibo; Lauder, George

    2016-11-01

    In many past studies on fish swimming, the hydrodynamics of fish caudal fins were investigated separately. However, fish body inevitably interacts with the caudal fin since the fin flaps in the wake of the body during swimming. In this work, an integrated experimental and computational approach has been used to investigate hydrodynamic performance improvement and the vortex dynamics associated with the fin-body interactions of a jack fish in steady swimming. Realistic 3D jack fish geometry and the undulatory kinematics are reconstructed based on the output of a high-speed photogrammetry system. Hydrodynamic performance and wake structures are simulated by an in-house immersed-boundary-method flow solver. It is found that the body-fin interactions enhance the thrust production of the caudal fin by more than 30% compared to that produced by an isolated caudal fin. Further analysis on the vortex dynamics has shown that the vortices shed from the posterior part of the fish body are captured by the leading edge portion of the caudal fin. This further enhances the strength of the leading-edge vortex attaching to the caudal fin and results in larger thrust production. This work reveals a potential performance enhancement mechanism in fish's steady swimming. This work was supported by NSF CBET-1313217 and ONR MURI N00014-14-1-0533.

  15. Notch regulates blastema proliferation and prevents differentiation during adult zebrafish fin regeneration.

    Science.gov (United States)

    Münch, Juliane; González-Rajal, Alvaro; de la Pompa, José Luis

    2013-04-01

    Zebrafish have the capacity to regenerate several organs, including the heart and fins. Fin regeneration is epimorphic, involving the formation at the amputation plane of a mass of undifferentiated, proliferating mesenchymal progenitor-like cells, called blastema. This tissue provides all the cell types that form the fin, so that after damage or amputation the fin pattern and structure are fully restored. How blastema cells remain in this progenitor-like state is poorly understood. Here, we show that the Notch pathway plays an essential role during fin regeneration. Notch signalling is activated during blastema formation and remains active throughout the regeneration process. Chemical inhibition or morpholino-mediated knockdown of Notch signalling impairs fin regeneration via decreased proliferation accompanied by reduced expression of Notch target genes in the blastema. Conversely, overexpression of a constitutively active form of the Notch1 receptor (N1ICD) in the regenerating fin leads to increased proliferation and to the expansion of the blastema cell markers msxe and msxb, as well as increased expression of the proliferation regulator aldh1a2. This blastema expansion prevents regenerative fin outgrowth, as indicated by the reduction in differentiating osteoblasts and the inhibition of bone regeneration. We conclude that Notch signalling maintains blastema cells in a plastic, undifferentiated and proliferative state, an essential requirement for fin regeneration.

  16. Effect of the fins configuration on natural convection heat transfer experimentally and numerically

    Directory of Open Access Journals (Sweden)

    Ahmed F. Khudheyer, Zaid Hameed Hasan

    2015-01-01

    Full Text Available The cooling of the electronic systems, electrical systems, and CPU of the computer is very important; therefore this study is prepared to improve this aims. In this study, natural convection heat transfer from rectangular fins with five different figures (continuous fins, 1-interrupted fins, 4-interrupted fins, inclined fins and V-fins are investigated at different heat flux values (175, 350, 525, 700 and 875 Watt per square meter.The effect of base to ambient temperature difference for continuous fins, 1-interrupted fins, 4-interrupted fins, inclined fins and V-fins were determined. All types of the fins are made with different geometries by using CNC machine and wire cut machine, but it have some dimensions in common such as fins thickness (5mm, fins height (18mm, space between the fins (10mm, and the volume of the base plat of heat sink (300*95*2mm. The heat sink base plate was heated by an attached maximum electric heater 2225 W/m2 with an identical size with the base plate of the heat sink, which could supply a specific heat flux. The steady-state temperature of the base plate was measured by eleven copper-constantan (K-type thermocouples inserted into different grooves in the base plate and glued with thermal tape and epoxy to ensure good thermal contact. The mathematical model of the base plate and fins are solved numerically using COMSOL (5.0 after describing the mesh model using the COMSOL (5.0 and assuming the properties of air variation with film temperature. After finding the numerical result, the validation between experimental and numerical results has been verified. Good agreement has been found between the experimental and CFD results. Empirical correlations for the overall Nusselt number versus average Rayleigh number for these configurations are obtained and compared to other correlations sited in the literature. The range of Rayleigh number, Nusselt number and base plate temperature are, (1.7e7 - 12.5e7, (37 – 83 and (25.6

  17. Functional morphology of undulatory pectoral fin locomotion in the stingray taeniura lymma (Chondrichthyes: dasyatidae)

    Science.gov (United States)

    Rosenberger; Westneat

    1999-12-01

    Rajiform locomotion is a unique swimming style found in the batoid fishes (skates and rays) in which thrust is generated by undulatory waves passing down the enlarged pectoral fins. We examined the kinematic patterns of fin motion and the motor patterns of pectoral fin muscles driving the locomotor system in the blue-spot stingray Taeniura lymma. Our goals in this study were to determine overall patterns of fin motion and motor control during undulatory locomotion, to discover how these patterns change with swimming velocity and to correlate muscle function with kinematics and pectoral morphology. Kinematic data were recorded from five individuals over a range of swimming speeds from 22 to 55 cm s(-)(1) (0.9-3.0 DL s(-)(1), where DL is body disc length). Electromyographic (EMG) data were recorded from three individuals over a range of velocities (1.2-3.0 DL s(-)(1)) at seven locations (four dorsal, three ventral) along the pectoral fin. As swimming velocity increases, fin-beat frequency, wavespeed and stride length increase, number of waves and reduced frequency decrease and fin amplitude remains constant. There is variability among individuals in frequency and amplitude at a given speed. An inverse relationship was found in which a high fin-beat frequency is associated with a low fin amplitude and a low fin-beat frequency is associated with a high fin amplitude. The motor pattern of undulatory locomotion is alternate firing activity in the dorsal and ventral muscles as the wave moves along the fin from anterior to posterior. Fin muscles are active along the entire length of the fin except at the lowest speeds. As swimming velocity and fin-beat frequency increase, the time of activation of posterior muscles becomes earlier relative to the onset of activity in the anterior dorsal muscles. The duration of muscle activity is longer in the ventral muscles than in the dorsal muscles, indicating that they play a central role in the power stroke of the fin-beat cycle. The

  18. Optimization of triangular fins with/without longitudinal perforate for thermal performance enhancement

    Energy Technology Data Exchange (ETDEWEB)

    Shadlaghni, A.; Tavakoli, M. R.; Farzaneh, M.; Salimpour, M. R. [Isfahan University, Isfahan (Iran, Islamic Republic of)

    2016-04-15

    This study aimed at determining a suitable pattern to allow for a better design of the fins used in heat sinks. Flow was considered laminar and steady, and the studied heat transfer mechanism was forced convection. Considering a fixed fin volume, the shape of fin cross section and its dimensions were optimized to maximize the heat transfer rate in a given physical condition. Numerical results showed that at a constant fin base area, heat transfer rate was higher in a fin with a triangular cross section compared to the fins with rectangular or trapezoidal cross sections. Investigation of optimum dimensional ratio in triangular fins showed that an increased height/thickness ratio enhanced the heat transfer rate. The effect of vertical position of the longitudinal perforations with different cross sections but similar volume ratios on the thermal performance of triangular fins was also examined. Results showed that perforation enhanced the thermal performance of the fins. Perforations with square and circular cross sections had almost identical thermal performances and dissipated more heat compared to those with triangular perforations.

  19. Comparative study on thermal performance of natural draft cooling towers with finned shells

    Energy Technology Data Exchange (ETDEWEB)

    Goodarzi, Mohsen [Bu-Ali Sina Univ., Hamedan (Iran, Islamic Republic of). Dept. of Mechanical Engineering

    2016-10-15

    The cooling efficiency of natural draft cooling towers under crosswind condition should be improved. In the present research work three different externally finned shells were considered for a typical natural draft cooling tower to investigate the cooling improvement. They were numerically simulated under normal and crosswind conditions. Numerical results show that twisting four fin plates over the tower shell along the 45 peripheral angle, could improve the cooling efficiency up to 6.5 %. Because of the periodic shape of the fin plates, the cooling efficiency of the cooling tower with finned shell is less sensitive to the change of wind.

  20. Energetics of median and paired fin swimming, body and caudal fin swimming, and gait transition in parrotfish (Scarus schlegeli) and triggerfish (Rhinecanthus aculeatus)

    DEFF Research Database (Denmark)

    Korsmeyer, Keith E; Steffensen, John Fleng; Herskin, Jannik

    2002-01-01

    exclusively with the pectoral fins at prolonged swimming speeds up to 3.2 total lengths per second (L s(-1); 30 min critical swimming speed, U(crit)). At higher speeds, gait transferred to a burst-and-coast BCF swimming mode that resulted in rapid fatigue. The triggerfish swam using undulations of the soft...... dorsal and anal fins up to 1.5 L s(-1), beyond which BCF undulations were recruited intermittently. BCF swimming was used continuously above 3.5 L s(-1), and was accompanied by synchronous undulations of the dorsal and anal fins. The triggerfish were capable of high, prolonged swimming speeds of up to 4...

  1. Heat transfer during boiling at finned tubes and finned tube bundles; Der Waermeuebergang beim Sieden an Rippenrohren und Rippenrohrbuendeln

    Energy Technology Data Exchange (ETDEWEB)

    Chen Qiurong

    1991-06-10

    Based on bubble dynamics at single tubes and hydrodynamics at multi-tube arrangements (a vertical tube row, tube bundle), a theory for calculation of heat transfer at single tubes, at a vertical tube row and at tube bundles was developed. The theory applies both to finned tubes and plain tubes. To verify the presented theory, measured heat transfer coefficients taken from literature are recalculated. A comparison between heat transfer coefficients for single tubes and two-tube arrangements, calculated according to the theory and determined by measurements shows good agreement. Measuring results for plain tube bundles and bundles of finned tubes also agree well with the theory. (orig./MM) [Deutsch] Aufbauend auf der Blasendynamik an Einzelrohren und der Hydrodynamik in Mehrrohranordnungen (eine senkrechte Rohrreihe, Rohrbuendel) wurde eine Theorie zur Berechnung des Waermeuebergangs an Einzelrohren, an einer senkrechten Rohrreihe und an Rohrbuendeln entwickelt. Die Theorie gilt sowohl fuer Rippenrohre als auch fuer Glattrohre. Zur Ueberpruefung der vorgestellten Theorie werden gemessene Waermeuebergangskoeffizienten aus der Literatur nachgerechnet. Ein Vergleich zwischen den nach der Theorie berechneten und den aus Messungen ermittelten Waermeuebergangskoeffizienten fuer Einzelrohre und Zweirohranordnungen zeigt gute Uebereinstimmung. Auch die Messergebnisse von Glattrohrbuendeln und von Buendeln mit den Rippenrohren lassen sich durch die Theorie gut wiedergeben. (orig./MM)

  2. Construcción de un polideportivo para las comunidades del entorno del lago Amatitlán, Guatemala

    OpenAIRE

    Pérez Salgado, Luis Daniel

    2012-01-01

    PFC realizado dentro de la convocatoria del Vicerrectorado de Relaciones Internacionales y Cooperación de la UBU de ayudas para el programa de proyectos de fin de carrera, practicum y prácticas universitarias en el ámbito de la cooperación internacional para el desarrollo

  3. Enhancement of natural convection heat transfer from a fin by triangular perforation of bases parallel and toward its tip

    Institute of Scientific and Technical Information of China (English)

    Abdullah H. AlEssa; Mohamad I. Al-Widyan

    2008-01-01

    This study examines the heat transfer enhancement from a horizontal rect- angular fin embedded with triangular perforations (their bases parallel and toward the fin tip) under natural convection. The fin's heat dissipation rate is compared to that of an equivalent solid one. The parameters considered axe geometrical dimensions and thermal properties of the fin and the perforations. The gain in the heat transfer enhancement and the fin weight reduction due to the perforations are considered. The study shows that the heat dissipation from the perforated fin for a certain range of triangular perforation di- mensions and spaces between perforations result in improvement in the heat transfer over the equivalent solid fin. The heat transfer enhancement of the perforated fin increases as the fin thermal conductivity and its thickness are increased.

  4. Effect of an Artificial Caudal Fin on the Performance of a Biomimetic Fish Robot Propelled by Piezoelectric Actuators

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper addresses the design of a biomimetic fish robot actuated by piezoceramic actuators and the effect of artificial caudal fins on the fish robot's performance. The limited bending displacement produced by a lightweight piezocomposite actuator was amplified and transformed into a large tail beat motion by means of a linkage system. Caudal fins that mimic the shape of a mackerel fin were fabricated for the purpose of examining the effect of caudal fin characteristics on thrust production at an operating frequency range. The thickness distribution of a real mackerel's fin was measured and used to design artificial caudal fins. The thrust performance of the biomimetic fish robot propelled by fins of various thicknesses was examined in terms of the Strouhal number, the Froude number, the Reynolds number, and the power consumption. For the same fin area and aspect ratio, an artificial caudal fin with a distributed thickness shows the best forward speed and the least power consumption.

  5. Caracterización de un robot para aplicaciones de mecanizado con requerimientos de tolerancias

    OpenAIRE

    Ferreras Higuero, Eugenio

    2014-01-01

    El presente Trabajo fin Fin de Máster, versa sobre una caracterización preliminar del comportamiento de un robot de tipo industrial, configurado por 4 eslabones y 4 grados de libertad, y sometido a fuerzas de mecanizado en su extremo. El entorno de trabajo planteado es el de plantas de fabricación de piezas de aleaciones de aluminio para automoción. Este tipo de componentes parte de un primer proceso de fundición que saca la pieza en bruto. Para series medias y altas, en función de las pr...

  6. Caracterización de un robot para aplicaciones de mecanizado con requerimientos de tolerancias

    OpenAIRE

    Ferreras Higuero, Eugenio

    2015-01-01

    El presente Trabajo fin Fin de Máster, versa sobre una caracterización preliminar del comportamiento de un robot de tipo industrial, configurado por 4 eslabones y 4 grados de libertad, y sometido a fuerzas de mecanizado en su extremo. El entorno de trabajo planteado es el de plantas de fabricación de piezas de aleaciones de aluminio para automoción. Este tipo de componentes parte de un primer proceso de fundición que saca la pieza en bruto. Para series medias y altas, en función de las pr...

  7. Líneas actividades indicadores y metas estratégicas para el Plan de Mejoramiento Estratégico para el servicio de salud de la Institución Penitenciaria de Acacias

    OpenAIRE

    Rojas Gutiérrez, Dania Magnolia

    2013-01-01

    El presente trabajo tiene como objetivo establecer un plan de de mejoramiento estratégico que permita optimizar el servicio de salud de la Institución Penitenciaria de Acacias. Para lograr este fin se hace un análisis del sector carcelario y penitenciario en Colombia con el fin de identificar la problemática que lo viene afectando en los últimos años, se establece un diagnostico en la Penitenciaria de Acacias con el fin de establecer la problemática que existe en la prestación de servicio...

  8. Prediction of fluid flow and heat transfer in internally finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hashem, M.Y.

    1993-01-01

    Fully developed fluid flow and heat transfer characteristics in internally finned tubes were investigated. Both laminar and turbulent flows were considered. Longitudinal fins of trapezoidal profile integrally attached to the tube wall are equally spaced circumferentially in the tube. The assumption of axially constant heat flux per unit length was applied. The tube wall temperature was assumed to be circumferentially uniform at any cross section but varies axially with the change of the bulk temperature. With a fin of finite conductivity, the temperature varies along the fin height. The influence of the ratio of the fin to fluid thermal conductivity ratio, K[sub fin]/K[sub fluid], was investigated for both laminar and turbulent flows. Results for laminar flow case were presented for a fin height to tube radius ratio H/R, ranging from 0.2 to 0.9; the number of fins, NFIN, was varied from 6 to 30; and fin half angles, beta, were varied from 1.5 to 3 degrees. It was found that for any specified geometry the Nusselt number is influenced by a single parameter, K[sub fin]/K[sub fluid]. A mixing length model developed by Ivanovic and Patankar was used to predict the results for turbulent fluid flow. Results were presented for a range of fin height to tube radius, H/R, which was varied from 0.2 to 0.4; NFIN ranged from 6 to 22; beta was selected as 1.5 and 3 degrees; and Reynolds number, Re, varied from 10,000 to 100,000. Predicted results for isothermal fins were shown to be in agreement with other researchers. The results provide extensive information on the influence of the fin to fluid thermal conductivities ratio. It is evident from the results that the assumption of isothermal fins is an inaccurate one, especially at high Reynolds number and either high H/R or low K[sub fin]/K[sub fluid] ratio.

  9. The morphology of the cephalic lobes and anterior pectoral fins in six species of batoids.

    Science.gov (United States)

    Mulvany, Samantha; Motta, Philip J

    2013-09-01

    Many benthic batoids utilize their pectoral fins for both undulatory locomotion and feeding. Certain derived, pelagic species of batoids possess cephalic lobes, which evolved from the anterior pectoral fins. These species utilize the pectoral fins for oscillatory locomotion while the cephalic lobes are used for feeding. The goal of this article was to compare the morphology of the cephalic lobes and anterior pectoral fins in species that possess and lack cephalic lobes. The skeletal elements (radials) of the cephalic lobes more closely resembled the radials in the pectoral fin of undulatory species. Second moment of area (I), calculated from cephalic lobe radial cross sections, and the number of joints revealed greater flexibility and resistance to bending in multiple directions as compared to pectoral fin radials of oscillatory species. The cephalic lobe musculature was more complex than the anterior pectoral fin musculature, with an additional muscle on the dorsal side, with fiber angles running obliquely to the radials. In Rhinoptera bonasus, a muscle presumably used to help elevate the cephalic lobes is described. Electrosensory pores were found on the cephalic lobes (except Mobula japonica) and anterior pectoral fins of undulatory swimmers, but absent from the anterior pectoral fins of oscillatory swimmers. Pore distributions were fairly uniform except in R. bonasus, which had higher pore numbers at the edges of the cephalic lobes. Overall, the cephalic lobes are unique in their anatomy but are more similar to the anterior pectoral fins of undulatory swimmers, having more flexibility and maneuverability compared to pectoral fins of oscillatory swimmers. The maneuverable cephalic lobes taking on the role of feeding may have allowed the switch to oscillatory locomotion and hence, a more pelagic lifestyle. Copyright © 2013 Wiley Periodicals, Inc.

  10. Physical Scaling Limits of FinFET Structure: A Simulation Study

    Directory of Open Access Journals (Sweden)

    Gaurav Saini

    2011-03-01

    Full Text Available In this work an attempt has been made to analyze the scaling limits of Double Gate (DG underlap andTriple Gate (TG overlap FinFET structure using 2D and 3D computer simulations respectively. Toanalyze the scaling limits of FinFET structure, simulations are performed using three variables: finthickness,fin-height and gate-length. From 2D simulation of DG FinFET, it is found that the gate-length(L and fin-thickness (Tfin ratio plays a key role while deciding the performance of the device. DrainInduced Barrier Lowering (DIBL and Subthreshold Swing (SS increase abruptly when (L/Tfin ratio goesbelow 1.5. So, there will be a trade-off in between SCEs and on- current of the device since on-off currentratio is found to be high at small dimensions. From 3D simulation study on TG FinFET, It is found thatboth fin-thickness (Tfin and fin-height (Hfin can control the SCEs. However, Tfin is found to be moredominant parameter than Hfin while deciding the SCEs. DIBL and SS increase as (Leff/Tfin ratiodecreases. The (Leff/Tfin ratio can be reduced below 1.5 unlike DG FinFET for the same SCEs. However,as this ratio approaches to 1, the SCEs can go beyond acceptable limits for TG FinFET structure. Therelative ratio of Hfin and Tfin should be maximum at a given Tfin and Leff to get maximum on-current perunit width. However, increasing Hfin degrades the fin stability and degrades SCEs.

  11. Evaluación de Intercambiadores de Calor Compactos de Tubos Aletados Evaluation of Compact Finned-Tube Heat Exchangers

    Directory of Open Access Journals (Sweden)

    M.T. Martínez

    2004-01-01

    Full Text Available En este trabajo, se presenta el análisis térmico teórico de un intercambiador de calor compacto, con y sin condensación de agua en el lado del aire. El fenómeno de la condensación del vapor de agua en la corriente de aire entrante produce una película de agua en la superficie cubriéndola en forma parcial o completa. El análisis considera varias configuraciones geométricas con respecto a: la superficie de las aletas y a la forma de los tubos considerando la forma circular tradicional y también un caso para tubos planos. Los resultados obtenidos reflejan la eficiencia de la aleta en ambos casos: una aleta totalmente seca (sin condensación y a una totalmente húmeda es decir, totalmente cubierta por la película de condensado. Se concluye que la metodología propuesta es una buena alternativa de análisis y caracterización de un intercambiador, ya que los resultados obtenidos coinciden con los reportados en la literaturaThis study presents a theoretical thermal analysis of a compact heat exchanger, with and without water condensation on the air side. The phenomenon of condensation of water vapor in the entering air current produces a film of water on the surface, partially or completely covering the surface. The analysis considers various geometric configurations with respect to the surfaces of the fins and the form of the tubes, including the traditional round form as well as flattened tubes. The results obtained reflect the efficiency of the fins in both cases , including a completely dry fin (no condensation and a completely wet fin, that is completely covered with a film of condensate. It is concluded that the methodology proposed is a good alternative for the analysis and characterization of a heat exchanger since the results agree with those reported in the literature

  12. Depth-Trim Mapping Control of Underwater Vehicle with Fins

    Institute of Scientific and Technical Information of China (English)

    LI Ye; PANG Yong-jie; HUANG Shu-ling; WAN Lei

    2011-01-01

    Underwater vehicle plays an important role in ocean engineering.Depth control by fin is one of the difficulties for underwater vehicle in motion control.Depth control is indirect due to the freedom coupling between trim and axial motion.It includes the method of dynamic analysis and lift-resistance-coefficient experiment and theory algorithm.By considering the current speed and depth deviation,comprehensive interpretation is used in object-planning instruction.Expected depth is transformed into expected trim.Dynamic output fluctuation can be avoided,which is caused by linear mapping of deviation.It is steady and accurate for the motion of controlled underwater vehicles.The feasibility and efficiency of the control method are testified in the pool and natural area for experiments.

  13. Applications of conducting polymers: robotic fins and other devices

    Science.gov (United States)

    Tangorra, James L.; Anquetil, Patrick A.; Weideman, Nathan S.; Fofonoff, Timothy; Hunter, Ian W.

    2007-04-01

    Conducting polymers are becoming viable engineering materials and are gradually being integrated into a wide range of devices. Parallel efforts conducted to characterize their electromechanical behavior, understand the factors that affect actuation performance, mechanically process films, and address the engineering obstacles that must be overcome to generate the forces and displacements required in real-world applications have made it possible to begin using conducting polymers in devices that cannot be made optimal using traditional actuators and materials. The use of conducting polymers has allowed us to take better advantage of biological architectures for robotic applications and has enabled us to pursue the development of novel sensors, motors, and medical diagnostic technologies. This paper uses the application of conducting polymer actuators to a biorobotic fin for unmanned undersea vehicles (UUVs) as a vehicle for discussing the efforts in our laboratory to develop conducting polymers into a suite of useful actuators and engineering components.

  14. Computational nano OPC DFM for LV Fin-type SRAM

    Science.gov (United States)

    Kadota, Kazuya

    2016-05-01

    Design For Manufacturing (DFM) where the state-of-the-art nano-devices of the sub-20nm node to a subject, for each of the technology has been intricately sophisticated, comprehensive optimization to predict the performance of the device came become very important. [1] To get effective solutions on these subjects, one of the lithographic key is a nano Optical Proximity Correction (OPC) control with SMO technology, and another is TCAD approach using the most advanced computer simulations. And, it is very important to obtain DFM solutions by integrating both. On the other hand, to meet the needs of low-voltage drive and the characteristic variability reduction, in order to obtain a state-of-the-art device performance, the Fin-type transistors are introduced globally as the mainstream because of wider process control margin. This paper, from the point of view of the sub-20nm node DFM, the simulation are conducted on ArF-imm. technology with SMO in SPT, DPT and QPT on TachyonTM [2], and the guideline of design rules are obtained. Furthermore, the simulated transistor pattern shape are directly migrated into TCAD process flow on HyENEXSSTM [3]. Then calculated I-V characteristics on 6 transistors under the various parameters on TCAD, and finally summarized Static Noise Margin (SNM) of SRAMs. Here, various parameters that determine the performance of SRAMs (Fin width, height, angle, dopant concentrations, electric field strength, work function, drive voltage, and operation speed) are intentionally varied and calculated on the TCAD. This computational method is highly sophisticated DFM technology to predict for the leading-edge nano-devices toward for the sub-20nm nodes era [4] [5] [6] [7] .

  15. Filipinas, fin de siglo: imágenes y realidad

    Directory of Open Access Journals (Sweden)

    Elizalde, María Dolores

    1998-08-01

    Full Text Available The objective of this paper is to present an image of the Philippines at the end of the 19th century, different to the picture of underveloped islands, inhabitated by savages unable to selfgovernment, transmited by the historiography and caricatures of that time. With this purpose, they are studied the process of redefinition of the Spanish colonial goverment, the strengthening of a new filipino society, the development of the economy and commerce, and the strong international interests in the islands.

    El presente artículo pretende ofrecer una imagen de las Filipinas de fin de siglo, diferente de la transmitida por la historiografía tradicional y por la viñetas y caricaturas de la época. Frente a los estereotipos de unas islas atrasadas, incapaces del autogobierno, habitadas por salvajes a los que había que civilizar, se impone una realidad definida por el gobierno colonial de España, en pleno proceso de redefinición; por el afianzamiento de una burguesía ilustrada filipina, la pujanza de una clase campesina y obrera, la fuerza de un movimiento de afirmación nacional, y el desarrollo de una economía agroexportadora en pleno crecimiento; y por la presencia de fuertes intereses internacionales que hay que entender insertos en la marea de expansión colonial y reparto de mercados y territorios ultramarinos; intereses internacionales de los que se da cuenta a través de un análisis de comercio, inversiones y presencia diplomática de las grandes potencias en las Filipinas de fin de siglo.

  16. Bigh3 is upregulated in regenerating zebrafish fin.

    Science.gov (United States)

    Page, Lionel; Polok, Bozena; Bustamante, Mauro; Schorderet, Daniel F

    2013-03-01

    Zebrafish is a good model for studying regeneration because of the rapidity with which it occurs. Better understanding of this process may lead in the future to improvement of the regenerating capacity of humans. Signaling factors are the second largest category of genes, regulated during regeneration after the regulators of wound healing. Major developmental signaling pathways play a role in this multistep process, such as Bmp, Fgf, Notch, retinoic acid, Shh, and Wnt. In the present study, we focus on TGF-β-induced genes, bigh3 and bambia. Bigh3 encodes keratoepithelin, a protein first identified as an extracellular matrix protein reported to play a role in cell adhesion, as well as in cornea formation and osteogenesis. The expression of bigh3 in zebrafish fins has previously been reported. Here we demonstrate that tgf-b1 and tgf-b3 mRNA reacted with delay, first showing no regulation at 3 dpa, followed by upregulation at 4 and 5 dpa. Tgf-b1, tgf-2, and tgf-brII mRNA were back to normal levels at 10 dpa. Only tgf-b3 mRNA was still upregulated at that time. Bigh3 mRNA followed the upregulation of tgf-b1, while bambia mRNA behaved similarly to tgf-b2 mRNA. We show that upregulation of bigh3 and bambia mRNA correlated with the process of fin regeneration and regulation of TGF-b signaling, suggesting a new role for these proteins.

  17. Quasi-stationary phase change heat transfer on a fin

    Science.gov (United States)

    Orzechowski, Tadeusz; Stokowiec, Katarzyna

    2016-03-01

    The paper presents heat transfer research basing on a long fin with a circular cross-section. Its basis is welded to the pipe where the hot liquid paraffin, having a temperature of 70°C at the inflow, is pumped. The analyzed element is a recurrent part of a refrigeration's condenser, which is immersed in a paraffin. The temperature of the inflowing liquid is higher than the temperature of the melting process for paraffin, which allows the paraffin to liquify. The temperature at the basis of the rib changes and it is assumed that the heat transfer is quasi-stationary. On this basis the estimation of the mean value of heat transfer coefficient was conducted. The unsteady thermal field of the investigated system was registered with an infrared camera V50 produced by a Polish company Vigo System. This device is equipped with a microbolometric detector with 384 × 288 elements and the single pixel size 25 × 25 μm. Their thermal resolution is lower than 70 mK at a temperature of 30 °C. The camera operates at 7,5 ÷ 14 μm long-wave infrared radiation range. For a typical lens 35 mm the special resolution is 0.7 mrad. The result of the calculations is mean heat transfer coefficient for the considered time series. It is equal to 50 W m -2 K-1 and 47 W m -2 K-1 on the left and right side of the fin, respectively. The distance between the experimental data and the curve approximating the temperature distribution was assessed with the standard deviation, Sd = 0.04 K.

  18. Quasi-stationary phase change heat transfer on a fin

    Directory of Open Access Journals (Sweden)

    Orzechowski Tadeusz

    2016-01-01

    Full Text Available The paper presents heat transfer research basing on a long fin with a circular cross-section. Its basis is welded to the pipe where the hot liquid paraffin, having a temperature of 70°C at the inflow, is pumped. The analyzed element is a recurrent part of a refrigeration’s condenser, which is immersed in a paraffin. The temperature of the inflowing liquid is higher than the temperature of the melting process for paraffin, which allows the paraffin to liquify. The temperature at the basis of the rib changes and it is assumed that the heat transfer is quasi-stationary. On this basis the estimation of the mean value of heat transfer coefficient was conducted. The unsteady thermal field of the investigated system was registered with an infrared camera V50 produced by a Polish company Vigo System. This device is equipped with a microbolometric detector with 384 × 288 elements and the single pixel size 25 × 25 μm. Their thermal resolution is lower than 70 mK at a temperature of 30 °C. The camera operates at 7,5 ÷ 14 μm long-wave infrared radiation range. For a typical lens 35 mm the special resolution is 0.7 mrad. The result of the calculations is mean heat transfer coefficient for the considered time series. It is equal to 50 W m −2 K−1 and 47 W m −2 K−1 on the left and right side of the fin, respectively. The distance between the experimental data and the curve approximating the temperature distribution was assessed with the standard deviation, Sd = 0.04 K.

  19. Experimental study on condensation heat transfer enhancement by various kinds of integral finned tubes. Hankei hoko ni tokki wo motsu shuhoko fin ni yoru gyoshuku netsudentatsu sokushin

    Energy Technology Data Exchange (ETDEWEB)

    Hijikata, K. (Tokyo Inst. of Technology., Tokyo (Japan)); Wang, S.

    1990-07-25

    Condensation heat transfer enhancement by a finned tube having radial ridges on the fin surface (called the R-tube), was investigated. Thermoexcel-C has a flat fin surface, while the R-tube has ridges on the fin surface, consequently the mean heat-transfer coefficient of the R-tube is 30-40% higher than that of Thermoexcel-C, in spite of same condensing areas in the two. The function of ridges on the fin surface of the R-tube to heat transfer enhancement, is remarkable. It is considered that a thin condensate film is formed on the tip of ridges, in the same way as that on the tip of fin without having ridges. The ridges disturb the flow of condensate in the channel, and promote a convective heat transfer due to an agitation action. Though the R-tube shows superior performance than other heat transfer tubes, the mechanisms of heat transfer enhancement are different in the upper part and the lower part of the tube. In the upper part of the tube, the effect of heat transfer enhancement due to the formation of thin film region by the ridges, is predominant. And in the lower part, the enhancement effect due to the convective heat transfer by the agitation of the condensate, is important. 13 refs., 10 figs., 1 tab.

  20. Ontogenetic scaling of caudal fin shape in Squalus acanthias (Chondrichthyes, Elasmobranchii): a geometric morphometric analysis with implications for caudal fin functional morphology.

    Science.gov (United States)

    Reiss, Katie L; Bonnan, Matthew F

    2010-07-01

    The shark heterocercal caudal fin and its contribution to locomotion are of interest to biologists and paleontologists. Current hydrodynamic data show that the stiff dorsal lobe leads the ventral lobe, both lobes of the tail are synchronized during propulsion, and tail shape reflects its overall locomotor function. Given the difficulties surrounding the analysis of shark caudal fins in vivo, little is known about changes in tail shape related to ontogeny and sex in sharks. A quantifiable analysis of caudal fin shape may provide an acceptable proxy for inferring gross functional morphology where direct testing is difficult or impossible. We examined ontogenetic and sex-related shape changes in the caudal fins of 115 Squalus acanthias museum specimens, to test the hypothesis that significant shape changes in the caudal fin shape occur with increasing size and between the sexes. Using linear and geometric morphometrics, we examined caudal shape changes within the context of current hydrodynamic models. We found no statistically significant linear or shape difference between sexes, and near-isometric scaling trends for caudal dimensions. These results suggest that lift and thrust increase linearly with size and caudal span. Thin-plate splines results showed a significant allometric shape change associated with size and caudal span: the dorsal lobe elongates and narrows, whereas the ventral lobe broadens and expands ventrally. Our data suggest a combination of caudal fin morphology with other body morphology aspects, would refine, and better elucidate the hydrodynamic factors (if any) that underlie the significant shape changes we report here for S. acanthias.

  1. Computational investigation of heat transfer and pressure drop in a typical louver fin-and-tube heat exchanger for various louver angles and fin pitches

    Directory of Open Access Journals (Sweden)

    Okbaz Abdulkerim

    2017-01-01

    Full Text Available In this study 3-D numerical simulations on heat transfer and pressure drop characteristics for a typical louver fin-and- double-row tube heat exchanger were carried out. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles, fin pitch and Reynolds number, and reported in terms of Colburn j-factor and Fanning friction factor f. The heat transfer improvement and the corresponding pressure drop amounts were investigated depending on louver angles between 20° ≤Ө≤ 30°, louver pitch of Lp=3.8 mm and frontal velocities of U between 1.22 m/s - 3 m/s. In addition, flow visualization of detailed flow features results, such as velocity vectors, streamlines and temperature counters have been shown to understand heat transfer enhancement mechanism. The present results indicated that louver angle and fin pitch noticeably affected the thermal and hydraulic performance of heat exchanger. It has been seen that increasing louver angle, increases thermal performance while decreasing hydraulic performance associated to pressure drop for fin pitches of 3.2 mm and 2.5 mm. Fin pitch determines the flow behaviour that for fin pitch of 2 mm, increasing louver angle decreased heat transfer and pressure drop. Velocity vectors and streamlines give considerable information about the flow whether it is duct directed or louver directed. For all conditions the flow is louver directed.

  2. Heat transfer and pressure drop characteristics of the tube bank fin heat exchanger with fin punched with flow redistributors and curved triangular vortex generators

    Science.gov (United States)

    Liu, Song; Jin, Hua; Song, KeWei; Wang, LiangChen; Wu, Xiang; Wang, LiangBi

    2017-10-01

    The heat transfer performance of the tube bank fin heat exchanger is limited by the air-side thermal resistance. Thus, enhancing the air-side heat transfer is an effective method to improve the performance of the heat exchanger. A new fin pattern with flow redistributors and curved triangular vortex generators is experimentally studied in this paper. The effects of the flow redistributors located in front of the tube stagnation point and the curved vortex generators located around the tube on the characteristics of heat transfer and pressure drop are discussed in detail. A performance comparison is also carried out between the fins with and without flow redistributors. The experimental results show that the flow redistributors stamped out from the fin in front of the tube stagnation points can decrease the friction factor at the cost of decreasing the heat transfer performance. Whether the combination of the flow redistributors and the curved vortex generators will present a better heat transfer performance depends on the size of the curved vortex generators. As for the studied two sizes of vortex generators, the heat transfer performance is promoted by the flow redistributors for the fin with larger size of vortex generators and the performance is suppressed by the flow redistributors for the fin with smaller vortex generators.

  3. Heat transfer from rotating finned heat exchangers with different orientation angles

    Energy Technology Data Exchange (ETDEWEB)

    Tawfik, Adel Abdalla [Suez Canal University, Marine Engineering and Naval Architecture Department, Faculty of Engineering, Port Said (Egypt)

    2010-03-15

    The local and average heat transfer characteristics of spoke like fins that extend outward from a rotating shaft have been determined experimentally. The experiments encompassed a number of geometrical parameters, including the length and chord of the fins, the number of fins deployed around the circumference of the shaft and the orientation angles of the fin. The experiments cover a wider range of rotational speeds, which varies from 25 up to 2,000 rpm. Three wire heat flux sensors have been used in conjunction with a slip ring apparatus to evaluate the local and average heat transfer coefficients. The output results indicated that, the heat transfer transition on rotating fins occurs at Reynolds number lower than encountered on the stationary rectangular fins in crossflow. In general, with non zero incidence angle, the rotating system acts as a fan and creates axial air motion, which enhance the heat transfer rate. However, the effect of orientation angle reduces with increasing the rotational speed. The Nusselt number data are independent of the number of fins in the circumferential array at high rotational speed and are weakly dependent at low Reynolds numbers. To facilitate the use of the results for design, correlations were developed which represent the fin heat transfer coefficient as a continuous function of the investigated independent parameters. (orig.)

  4. Parametric analysis of the performance of internally finned tubes for heat exchanger application

    Energy Technology Data Exchange (ETDEWEB)

    Webb, R.L.; Scott, M.J.

    1980-02-01

    This paper presents a parametric analysis of the performance of internally finned tubes in turbulent forced convection for application to heat exchangers. The analysis compares the performance of an internally finned tube exchanger with that of an exchanger having internally smooth tubes. The calculations are performed for three important design cases.

  5. Convection heat transfer and pressure drop in cross flow over finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Baran, M.; Pronobis, M.

    1984-05-15

    This paper reports the results of an experimental study on the heat transfer and pressure drop in finned tube banks. The measurements were carried out for the tubes with fins arranged parallel and a certain angle to the flow direction. The performance of such a heat exchanger with that of the conventional one i.e. plain tube heat exchanger, is compared.

  6. Film condensation of R-113 on staggered bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, H. (Kyushu Univ., Fukuoka (Japan)); Uchima, B. (Kagawa Technical Coll., Marugame (Japan)); Nozu, S.; Torigoe, E.; Imai, S. (Okayama Univ., Tsushima (Japan))

    1992-05-01

    Film condensation of R-113 on staggered bundles of horizontal finned tubes with vertical vapor downflow was experimentally investigated. Two tubes with flat-sided annular fins and four tubes with three-dimensional fins were tested. The condensate flow and heat transfer characteristics were compared with the previous results for in-line bundles of the same test tubes and a staggered bundle of smooth tubes. The decrease in heat transfer characteristics were compared with the previous results for in-line bundles of the same test tubes and a staggered bundle of smooth tubes. The decrease in heat transfer due to condensate inundation was most significant for the in-line bundles of the three-dimensional fin tubes, whereas the decrease was very slow for both the staggered and in-line bundles of the flat-sided fin tubes. The predictions of the previous theoretical model for a bundle of flat-sided fin tubes agreed fairly well with the measured data at a low vapor velocity. The highest heat transfer performance was provided by the staggered bundle of flat-sided fin tubes with fin dimensions close to the theoretically determined optimum values.

  7. Experimental Study on Cooling Heat Transfer of Supercritical Carbon Dioxide Inside Horizontal Micro-Fin Tubes

    Science.gov (United States)

    Kuwahara, Ken; Higashiiu, Shinya; Ito, Daisuke; Koyama, Shigeru

    This paper deals with the experimental study on cooling heat transfer of supercritical carbon dioxide inside micro-fin tubes. The geometrical parameters in micro-fin tubes used in the present study are 6.02 mm in outer diameter, 4.76 mm to 5.11 mm in average inner diameter, 0.15 mm to 0.24 mm in fin height, 5 to 25 in helix angle, 46 to 52 in number of fins and 1.4 to 2.3 in area expansion ratio. Heat transfer coefficients were measured at 8-10 MPa in pressure, 360-690 kg/(m2•s) in mass velocity and 20-75 °C in CO2 temperature. The measured heat transfer coefficients of micro-fin tubes were 1.4 to 2 times higher than those of the smooth tube having 4.42 in inner diameter. The predicted heat transfer coefficients using the correlation equation, which was developed for single-phase turbulent fluid flow inside micro-fin-tubes, showed large deviations to the measured values. The new correlation to predict cooling heat transfer coefficient of supercritical carbon dioxide inside micro-fin tubes was developed taking into account the shape of fins based on experimental data empirically. This correlation equation agreed within ±20% of almost all of the experimental data.

  8. 3-D NUMERICAL STUDY AND COMPARISON OF ECCENTRIC AND CONCENTRIC ANNULAR-FINNED TUBE HEAT EXCHANGERS

    Directory of Open Access Journals (Sweden)

    FAROUK TAHROUR

    2015-11-01

    Full Text Available The use of 3-D computational fluid dynamics (CFD is proposed to simulate the conjugate conduction-convection of heat transfer problems in eccentric annularfinned tube heat exchangers. The numerical simulation results allow us to evaluate the heat transfer coefficient over fin surfaces, the fin efficiency and the pressure drop. The aim of the present paper is to determine the optimum tube position in the circular fin that maximizes heat dissipation and minimizes pressure drop. In addition, this study analyzes the effects of fin spacing and fin tube diameter on heat transfer and flow characteristics for a range of Reynolds numbers, 4500≤Re≤22500. A satisfactory qualitative and quantitative agreement was obtained between the numerical predictions and the results published in the literature. For small fin spacings, the eccentric annular finned tube is more efficient than the concentric one. Among the cases examined, the average heat transfer coefficient of the eccentric annular-finned tube, for a tube shift St =12 mm and a Reynolds number Re = 9923, was 7.61% greater than that of the concentric one. This gain is associated with a 43.09% reduction in pressure drop.

  9. State of FinTech in Europe: Mutation perspectives of the banking sector

    OpenAIRE

    Marasco, Marco

    2017-01-01

    This paper studies the relationship between FinTech start-ups and the banking sector. The aim is to assess the impact that the FinTech sector might have on the business model and profitability of banks. Master [120] en sciences de gestion (Mons), Université catholique de Louvain, 2017

  10. Analysis and Simulation of a Low-Leakage Analog Single Gate and FinFET Circuits

    Science.gov (United States)

    Chauhan, Manorama; Kushwah, Ravindra Singh; Shrivastava, Pavan; Akashe, Shyam

    2014-05-01

    In the world of Integrated Circuits, complementary metal-oxide-semiconductor (CMOS) has lost its ability during scaling beyond 50 nm. Scaling causes severe short channel effects (SCEs) which are difficult to suppress. FinFET devices undertake to replace usual Metal Oxide Semiconductor Field Effect Transistor (MOSFETs) because of their better ability in controlling leakage and diminishing SCEs while delivering a strong drive current. In this paper, we present a relative examination of FinFET with the double gate MOSFET (DGMOSFET) and conventional bulk Si single gate MOSFET (SGMOSFET) by using Cadence Virtuoso simulation tool. Physics-based numerical two-dimensional simulation results for FinFET device, circuit power is presented, and classifying that FinFET technology is an ideal applicant for low power applications. Exclusive FinFET device features resulting from gate-gate coupling are conversed and efficiently exploited for optimal low leakage device design. Design trade-off for FinFET power and performance are suggested for low power and high performance applications. Whole power consumptions of static and dynamic circuits and latches for FinFET device, believing state dependency, show that leakage currents for FinFET circuits are reduced by a factor of over 10X, compared to DGMOSFET and 20X compared with SGMOSFET.

  11. Characterization of strained silicon FinFETs and the integration of a piezoelectric layer

    NARCIS (Netherlands)

    Kaleli, Buket

    2013-01-01

    Strain is often applied in semiconductor technology to improve the device performance in a field effect transistor (FET). However, it increases the off-state current as well. In this work, we investigated so-called silicon-on-insulator (SOI) fin-shaped field-effect transistors (FinFETs) and the effe

  12. Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus

    Science.gov (United States)

    Centelleghe, Cinzia; Beffagna, Giorgia; Povinelli, Michele; Terracciano, Giuliana; Cocumelli, Cristiano; Pintore, Antonio; Denurra, Daniele; Casalone, Cristina; Pautasso, Alessandra; Di Francesco, Cristina Esmeralda; Di Guardo, Giovanni

    2016-01-01

    During 2011–2013, dolphin morbillivirus was molecularly identified in 4 stranded fin whales from the Mediterranean Sea. Nucleoprotein, phosphoprotein, and hemagglutinin gene sequences of the identified strain were highly homologous with those of a morbillivirus that caused a 2006–2007 epidemic in the Mediterranean. Dolphin morbillivirus represents a serious threat for fin whales. PMID:26812485

  13. Performance of residential air-conditioning systems with flow maldistribution in fin-and-tube evaporators

    DEFF Research Database (Denmark)

    Kærn, Martin Ryhl; Brix, Wiebke; Elmegaard, Brian;

    2011-01-01

    Refrigerant and airflow maldistribution in fin-and-tube evaporators for residential air-conditioning was investigated with numerical modeling. Fin-and-tube heat exchangers usually have a pre-defined circuitry. However, the objective in this study was to perform a generic investigation of each...

  14. CFD Analysis of Flow Characteristics of Corrugated Louvered Fins at Low Reynolds

    Institute of Scientific and Technical Information of China (English)

    QI Zhao-gang; CHEN Jiang-ping

    2005-01-01

    A 2-D laminar flow model was established for CFD analysis of air-flow between louvered fins. Two louvered fins are studied based on commercial software FLUENT. Air-flow pressure drop characteristics are derived on the calculation of Reynolds number from 75.3 to 600. The numerical results are in good agreement with the experimental data when Reynolds is lower.

  15. Mediterranean Fin Whales (Balaenoptera physalus) Threatened by Dolphin MorbilliVirus.

    Science.gov (United States)

    Mazzariol, Sandro; Centelleghe, Cinzia; Beffagna, Giorgia; Povinelli, Michele; Terracciano, Giuliana; Cocumelli, Cristiano; Pintore, Antonio; Denurra, Daniele; Casalone, Cristina; Pautasso, Alessandra; Di Francesco, Cristina Esmeralda; Di Guardo, Giovanni

    2016-02-01

    During 2011-2013, dolphin morbillivirus was molecularly identified in 4 stranded fin whales from the Mediterranean Sea. Nucleoprotein, phosphoprotein, and hemagglutinin gene sequences of the identified strain were highly homologous with those of a morbillivirus that caused a 2006-2007 epidemic in the Mediterranean. Dolphin morbillivirus represents a serious threat for fin whales.

  16. Proyecto educativo Matemática para la enseñanza media (MATEM), su quehacer académico durante el año 2012: Perspectiva de los participantes

    National Research Council Canada - National Science Library

    Ana Lucía Alfaro Arce; Marianela Alpízar Vargas; José Romilio Loría Fernández

    2014-01-01

    .... El objetivo de este artículo es mostrar sobre la indagación realizada sobre diversos aspectos del proyecto MATEM, con el fin de evaluar su desarrollo y considerar las recomendaciones para la toma de decisiones...

  17. ¿Un fin o un medio?: Contexto en el que se decide la reproducción

    Directory of Open Access Journals (Sweden)

    Diva Estela Jaramillo

    Full Text Available Estudio cualitativo que explora el proceso de toma de decisiones en la reproducción. Describe el contexto para dicha decisión. Se entrevistan 17 hombres y 23 mujeres, entre 20 y 35 años, de diferentes estratos sociales, procedencias y niveles educativos, con relación de pareja mayor a un año. Metodológicamente se apoya en la teoría fundada y el interaccionismo simbólico. Los hallazgos muestran diferentes significados de reproducirse y de interpretar las normas de género, los cuales guían las decisiones sobre la descendencia. Cuando las parejas entienden la reproducción como un fin, deciden prepararse y planear el número y el momento de realizarla. Son decisiones dialogadas y concertadas a la luz de sus planes de vida. Cuando entienden reproducirse como un medio para lograr fines individuales, como son, desde lo masculino obtener placer sexual o cuidados, y desde lo femenino, encontrar estabilidad afectiva, emocional y económica para tener unas determinadas condiciones de vida, las decisiones son individuales no negociadas. No se preparan, e interpretan rígidamente las normas de género, lo cual conduce a relaciones de inequidad. La reproducción no es motivo de preocupación y en consecuencia, los hijos aparecen inesperadamente, lo que se convierte en motivo permanente de conflicto entre la pareja.

  18. El fin del concurso y el del convenio

    OpenAIRE

    Sánchez-Calero Guilarte, Juan

    2016-01-01

    El trabajo aborda la relación que existe entre la finalidad del concurso y la utilización del convenio como solución prevista para el mismo. La realidad estadística demuestra que el convenio es una solución excepcional. El trabajo analiza la influencia que el fracaso del convenio tiene para la configuración del concurso como un procedimiento incompatible con la continuidad empresarial.

  19. Protection of Wild Adult Steelhead in Idaho by Adipose Fin Removal: 1984-1985 Annual Report.

    Energy Technology Data Exchange (ETDEWEB)

    Duke, Rodney C.

    1986-03-01

    All Idaho hatchery-reared steelhead released in the spring of 1985 received an adipose fin clip to differentiate between natural or wild and hatchery, fish, thus allowing for protection of wild fish in the sport harvest. Between 25 September and 14 December 1984, 6,360,542 steelhead trout (Salmo gairdneri) were marked by excising the adipose fin. A total of 10,336 man hours were required to complete the operation. Clip quality and healing, mortality, and adipose fin composition were determined. Quality checks indicated less than 1% of the fish had more than 25% of the fin remaining. Combined mortality at all three hatcheries was 0.3% of the total fish marked. Observed and in vivo test showed complete healing of the excision within 3-4 weeks (observed) and 22 days (in vivo). Bibliographies were compiled for fin regeneration, marked fish survival, hooking mortality, and related catch-and-release studies.

  20. Chemical milling of Zircaloy tubing to produce integral OD spiral finned tubes (AWBA development program)

    Energy Technology Data Exchange (ETDEWEB)

    Horwood, W.A.

    1982-02-01

    A detailed process description is provided for producing integral spiral fins on the outside surface of Zircaloy nuclear fuel cladding tubes by masking with pressure sensitive tape strips and then chemical milling (pickling) the tube wall between the tape strips to leave the fins in relief. Fins up to 0.020 inch high by 0.05 to 0.12 inch wide were consistently produced on tubes having wall thickness of 0.008 inch or greater after fin pickling. Wall thickness uniformity was excellent. Information is provided on tube surface preparation to maximize tape mask adhesion time during pickling, acid chemistry control to prevent local tube wall thinning near the fin, and pickling techniques to promote uniform material removal. Simple fixture designs are described for quickly and conveniently applying the tape strips to the tube wall in an accurate spiral. 13 figures, 4 tables.

  1. Heat Transfer between Horizontal Finned Tubes and a Gas-Solid Fluidized Bed

    Energy Technology Data Exchange (ETDEWEB)

    Grewal, N.S.; Cheung, T.K.; Saxena, S.C.

    1985-04-01

    The heat-transfer coefficients are measured between electrically heated V-thread tubes and square fluidized beds of alumina and silica sand. The effect of particle size, mass fluidizing velocity, V-thread pitch, and tube pitch on the heat transfer rate is investigated. One-dimensional and two-dimensional heat conduction models are developed for determining the temperature distribution in a V-thread fin. The models are used to calculate the corrected heat-transfer coefficients for the finned tubes. A correlation for the fin effectiveness factor is proposed and is found to be reliable to predict its value for finned tubes with geometry and orientation similar to that in the present investigation. The correlation in conjunction with the existing correlatins for the heat-transfer coefficient for smooth tubes is found, in general, to predict the coefficients for finned tubes immersed in a fluidized bed within + or - 25%.

  2. Performance investigation of evaporatively-cooled heat exchangers - part one: plain and finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, A.; Siren, K.

    2004-07-01

    The performance of two evaporatively cooled heat exchangers is investigated under similar operating conditions of airflow rates and inlet hot water temperatures. The types of the heat exchangers are plain and plate-finned circular tube which occupy the same volume. A substantial increase in heat transfer takes place for the plate-finned tubes. The increase is 92-140% for air velocities from 1.66 to 3.57 m s{sup -1}. The wet-finned surfaces show low fin efficiency compared with dry surfaces. An energy index defined as the ratio of volumetric thermal conductance to air pressure drop per unit length is found to be close for the two heat exchangers. This reveals higher thermal utilisation of the occupied volume by the finned tubes with the same energy index. (orig.)

  3. Convective Heat Transfer Augmentation by Flexible fins in Laminar Channel Pulsating flow

    CERN Document Server

    Joshi, Rakshitha U; Bhardwaj, Rajneesh

    2015-01-01

    Fluid-structure interaction (FSI) of thin flexible fins coupled with convective heat transfer has applications in energy harvesting and in understanding functioning of several biological systems. We numerically investigate FSI of the thin flexible fins involving large-scale flow-induced deformation as a potential heat transfer enhancement technique. An in-house, strongly-coupled fluid-structure interaction (FSI) solver is employed in which flow and structure solvers are based on sharp-interface immersed boundary and finite element method, respectively. We consider twin flexible fins in a heated channel with laminar pulsating cross flow. The vortex ring past the fin sweep higher sources of vorticity generated on the channel walls out into the downstream - promoting the mixing of the fluid. The moving fin assists in convective mixing, augmenting convection in bulk and at the walls; and thereby reducing thermal boundary layer thickness and improving heat transfer at the channel walls. The thermal augmentation is...

  4. Performance analysis of pin fins with temperature dependent thermal parameters using the variation of parameters method

    Directory of Open Access Journals (Sweden)

    Cihat Arslantürk

    2016-08-01

    Full Text Available The performance of pin fins transferring heat by convection and radiation and having variable thermal conductivity, variable emissivity and variable heat transfer coefficient was investigated in the present paper. Nondimensionalizing the fin equation, the problem parameters which affect the fin performance were obtained. Dimensionless nonlinear fin equation was solved with the variation of parameters method, which is quite new in the solution of nonlinear heat transfer problems. The solution of variation of parameters method was compared with known analytical solutions and some numerical solution. The comparisons showed that the solutions are seen to be perfectly compatible. The effects of problem parameters were investigated on the heat transfer rate and fin efficiency and results were presented graphically.

  5. Investigating the performance of SiGe embedded dual source p-FinFET architecture

    Science.gov (United States)

    Sinha, Kunal; Gupta, Partha Sarathi; Chattopadhyay, Sanatan; Rahaman, Hafizur

    2016-10-01

    In this work, a modified Fin shaped Field Effect Transistor (FinFET) structure has been proposed with dual SiGe embedded extended source regions. Comparative simulation studies with SiGe embedded source/drain conventional single Fin channel and dual Fin channel FinFET structure having similar device footprint area shows almost 3× and 1.5× improvement of drive current respectively and lower threshold voltage in the proposed architecture. The dual extended SiGe source regions and presence of Si drain in the vertical direction of the channel generate bi-axial channel stress which improves the channel charge density, which results in improvement in drive current significantly. Also it has been observed from various simulation studies that the separated gate regions increase the inversion current density in the channel which also leads to improvement of the device performance.

  6. Laminar fluid flow and heat transfer in a fin-tube heat exchanger with vortex generators

    Energy Technology Data Exchange (ETDEWEB)

    Yanagihara, J.I.; Rodriques, R. Jr. [Polytechnic School of Univ. of Sao Paolo, Sao Paolo (Brazil). Dept. of Mechanical Engineering

    1996-12-31

    Development of heat transfer enhancement techniques for fin-tube heat exchangers has great importance in industry. In recent years, heat transfer augmentation by vortex generators has been considered for use in plate fin-tube heat exchangers. The present work describes a numerical investigation about the influence of delta winglet pairs of vortex generators on the flow structure and heat transfer of a plate fin-tube channel. The Navier-Stokes and Energy equations are solved by the finite volume method using a boundary-fitted coordinate system. The influence of vortex generators parameters such as position, angle of attack and aspect ratio were investigated. Local and global influences of vortex generators in heat transfer and flow losses were analyzed by comparison with a model using smooth fin. The results indicate great advantages of this type of geometry for application in plate fin-tube heat exchangers, in terms of large heat transfer enhancement and small pressure loss penalty. (author)

  7. [Characteristics of the reparative regeneration of fins in the polypterid fish (Polypteridae, Actinopterygii)].

    Science.gov (United States)

    Nikiforova, A I; Golichenkov, V A

    2012-01-01

    Epimorphic regeneration of fins was studied in different ray-finned fishes (Actinopterygii), but species representing the phylogenetically basal lineages of the taxon have remained outside the attention of researchers. Information on the regenerative abilities of these groups is important both for understanding the evolutionary origins of the epimorphic regeneration phenomenon and for assessing the universality of regenerative potencies in Actinopterygii. Addressing this problem, we studied for the first time fin regeneration in two members of the archaic family Polypteridae: the ropefish (Erpetoichthys calabaricus) and the Senegal bichir (Polypterus senegalus). Along with the ability to regenerate the bony rays of fins, widespread among Actinopterygii, polypterids show the ability to effectively regenerate the endoskeleton and musculature of their fins. This unusual feature allows us to suggest polypterids as new model organisms for the study of the mechanisms of vertebrate limb regeneration.

  8. NUMERICAL STUDY ON FLOW DISTRIBUTION IN PLATE-FIN HEAT EXCHANGERS

    Institute of Scientific and Technical Information of China (English)

    张哲; 厉彦忠

    2003-01-01

    Objective To investigate the flow distribution in plate-fin heat exchangers and optimize the design of header configuration for plate-fin heat exchangers. Methods A mathematical model of header was proposed. The effects of the header configuration on the flow distribution in plate-fin heat exchangers were investigated by CFD. The second header configuration with a two-stage-distributing structure was brought forward to improve the performance of flow distribution. Results It is found that the flow maldistribution is very serious in the direction of header length for the conventional header used in industry. The numerical predictions indicate that the improved header configurations can effectively improve the performance of flow distribution in plate-fin heat exchangers. Conclusion The numerical simulation confirms that CFD should be a suitable tool for predicting the flow distribution. The method has a wide variety of applications in the design of plate-fin heat exchangers.

  9. Bio-inspired flexible joints with passive feathering for robotic fish pectoral fins.

    Science.gov (United States)

    Behbahani, Sanaz Bazaz; Tan, Xiaobo

    2016-05-04

    In this paper a novel flexible joint is proposed for robotic fish pectoral fins, which enables a swimming behavior emulating the fin motions of many aquatic animals. In particular, the pectoral fin operates primarily in the rowing mode, while undergoing passive feathering during the recovery stroke to reduce hydrodynamic drag on the fin. The latter enables effective locomotion even with symmetric base actuation during power and recovery strokes. A dynamic model is developed to facilitate the understanding and design of the joint, where blade element theory is used to calculate the hydrodynamic forces on the pectoral fins, and the joint is modeled as a paired torsion spring and damper. Experimental results on a robotic fish prototype are presented to illustrate the effectiveness of the joint mechanism, validate the proposed model, and indicate the utility of the proposed model for the optimal design of joint depth and stiffness in achieving the trade-off between swimming speed and mechanical efficiency.

  10. HEAT EXCHANGE AND AERODYNAMICS OF THE COMBINED TUBING BUNDLES WITH CROSS INCLINED FINS

    Directory of Open Access Journals (Sweden)

    Knyazyuk V. I

    2013-04-01

    Full Text Available The paper presents results of experimental research and analyses air-side thermal performance of combined tube bundles with cross inclined fins. The empirical correlations for heat transfer and flow friction of tubes with inclined fins at different orientation finned tubes relatively of air flow are presented. The errors of thermal and aerodynamic tests are 3-5% and 9.2%, respectively. The proposed correlations describe an experimental data with a coefficient of determination about 0.979-0.998. The impact of tubes arrangement in a bundle on energy performance of heat exchanger were analyzed using complete and local heat modeling methods at a stationary heat flux. Experimental research indicates that efficiency of inclined fins can be calculated by using the equation for cross rectangular fins with average deviation of ±5 %.

  11. Film condensation of downward flowing R-113 vapor on in-line bundles of horizontal finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Hiroshi; Uchima, Bunken; Nozu, Shigeru; Nakata, Hironori; Torigoe, Eiichi (Okayama Univ., Faculty of Engineering, Okayama, (Japan))

    1989-08-25

    The film condensation characteristics of a downward flowing R-113 vapor on in-line bundles of horizontal finned tubes were experimentally investigated using two tubes with flat-sided fins and four tubes with three-dimensional fins. The flow pattern of falling condensate on the finned tube bundle is similar to that on the smooth tube bundle, basically. The liquid filled position of tube with flat-sided fins is not affected by the vapor velocity. The effect of the vapor velocity on the film condensation in the finned tube bundle was considerably smaller than the case of the smooth tube bundle. The decrease of the heat transfer coefficient due to the condensate inundation was larger in case of the tubes with three-dimensional fins than in case of the tubes with flat-sided fins. While the tubes with three-dimensional fins showed contrary tendency against the tubes with flat-sided fins. Among six sample tubes, a tube with flat-sided fins of 0.5mm fin pitch and 1.3mm fin height showed the best heat transfer performance over the range of the whole experiment. 16 refs., 11 figs., 2 tabs.

  12. Una lectura de Esperando a Godot y Fin de partida a través de la melancolía

    OpenAIRE

    Lafuente Garcia, Meritxell

    2016-01-01

    Con la lectura de Esperando a Godot (1953) y Fin de partida (1957) a través del concepto freudiano de la melancolía, el presente artículo pretende demostrar a partir de qué mecanismos el teatro de Beckett queda legitimado. En un momento post-catástrofe en que la palabra parece haber quedado desprovista de sentido, Beckett encuentra la fórmula para crear dramas sin que estos sean vanos, y es a partir del análisis de elementos como el tiempo, el espacio y la memoria que la estructura de su teat...

  13. FEM simulation for cold press forging forming of the round-fin heat sink

    Science.gov (United States)

    Wang, Kesheng; Han, Yu; Zhang, Haiyan; Zhang, Lihan

    2013-05-01

    In this paper, the finite element method is used to investigate the forming process of cold press forging for the round-fin heat sink in the automotive lighting. A series of simulations on the round-fin heat sink forming using the program DEFORM were carried out. The blank thickness and friction coefficient on the formation of round-fin were studied, and the tooling structure with counterpressure on the heat sink formation was also investigated. The results show that the blank thickness is very good for the round-fin formation, and the thicker the blank is, the better the round-fin can be formed; and also When both the punch-blank interface and the die-blank interface have the same value of friction factor, the larger value of friction factor is in favor of round-fin forming, the further investigation reveals that the friction at the punch-blank interface has more significant effect on preventing the initiation of flow-through compared with the friction at the die-blank interface, which implies that the punch-blank interface has more significant effect on the material flow in the formation of round-fin. Meanwhile, The tooling structure with counterpressure is helpful to the formation of round-fin heat sink, which not only ensures the height of each round-fin on the heat sink is uniform but also retards the initiation of flow-through on the reverse side of round-fin. In addition, the experiments of press forging process were conducted to validate the finite element analysis, and the simulation results are in good agreement with the experimental data.

  14. The use of pelvic fins for benthic locomotion during foraging behavior in Potamotrygon motoro (Chondrichthyes: Potamotrygonidae

    Directory of Open Access Journals (Sweden)

    Akemi Shibuya

    2015-06-01

    Full Text Available Synchronized bipedal movements of the pelvic fins provide propulsion (punting during displacement on the substrate in batoids with benthic locomotion. In skates (Rajidae this mechanism is mainly generated by the crural cartilages. Although lacking these anatomical structures, some stingray species show modifications of their pelvic fins to aid in benthic locomotion. This study describes the use of the pelvic fins for locomotory performance and body re-orientation in the freshwater stingray Potamotrygon motoro (Müller & Henle, 1841 during foraging. Pelvic fin movements of juvenile individuals of P. motoro were recorded in ventral view by a high-speed camera at 250-500 fields/s-1. Potamotrygon motoro presented synchronous, alternating and unilateral movements of the pelvic fins, similar to those reported in skates. Synchronous movements were employed during straightforward motion for pushing the body off the substrate as well as for strike feeding, whereas unilateral movements were used to maneuver the body to the right or left during both locomotion and prey capture. Alternating movements of the pelvic fins are similar to bipedal movements in terrestrial and semi-aquatic tetrapods. The pelvic fins showed coordinated movements during feeding even when stationary, indicating that they have an important function in maintaining body posture (station holding during prey capture and manipulation. The use of pelvic fins during prey stalking may be advantageous because it results in less substrate disturbance when compared to movements generated by pectoral fin undulation. The range of pelvic fin movements indicates more complex control and coordination of the pelvic radial muscles.

  15. Characteristics and formation mechanism for stainless steel fiber with periodic micro-fins

    Science.gov (United States)

    Tang, Tao; Wan, Zhenping; Lu, Longsheng; Tang, Yong

    2016-05-01

    Metal fibers have been widely used in many industrial applications due to their unique advantages. In certain applications, such as catalyst supports or orthopedic implants, a rough surface or tiny outshoots on the surface of metal fibers to increase surface area are needed. However, it has not been concerned about the surface morphologies of metal fiber in the current research of metal fiber manufacturing. In this paper, a special multi-tooth tool composed of a row of triangular tiny teeth is designed. The entire cutting layer of multi-tooth tool bifurcates into several thin cutting layers due to tiny teeth involved in cutting. As a result, several stainless steel fibers with periodic micro-fins are produced simultaneously. Morphology of periodic micro-fins is found to be diverse and can be classified into three categories: unilateral plane, unilateral tapering and bilateral. There are two forming mechanisms for the micro-fins. One is that periodic burrs remained on the free side of cutting layer of a tiny tooth create micro-fins of stainless steel fiber produced by the next neighboring tiny tooth; the other is that the connections between two fibers stuck together come to be micro-fins if the two fibers are finally detached. Influence of cutting conditions on formation of micro-fins is investigated. Experimental results show that cutting depth has no significant effect on micro-fin formation, high cutting speed is conducive to micro-fin formation, and feed should be between 0.12 mm/r and 0.2 mm/r to reliably obtain stainless steel fiber with micro-fins. This research presents a new pattern of stainless steel fiber characterized by periodic micro-fins formed on the edge of fiber and its manufacturing method.

  16. MODELO PARA LA CREACIÓN DEL CONOCIMIENTO PARA PYMES

    Directory of Open Access Journals (Sweden)

    Marino Valencia Rodríguez

    2009-01-01

    Full Text Available La creciente importancia del conocimiento, como nuevo factor de producción, hace que la creación y transferencia se convierta en una de las principales prioridades de las organizaciones. El presente artículo describe tanto los fundamentos de la teoría de los recursos y capacidades de la empresa como el enfoque de la gestión del conocimiento, con sus procesos de generación y transferencia del conocimiento. Estos sirven de guía básica teórica para alcanzar el siguiente objetivo: Diseñar un modelo de generación y transferencia de conocimiento para los procesos de dirección, gestión humana y del conocimiento para PyMES, con el fin de que éstas alcancen mayores niveles de competitividad. El modelo se diseña, a partir del direccionamiento estratégico de la organización. Está conformado por tres etapas, articuladas con elementos y actividades. Las acciones se enfocan en dos factores clave de éxito: la cultura organizacional y la formación. La utilización del modelo permitirá a las PyMES optimizar los recursos y capacidades disponibles, lo cual se refleja en el desempeño del trabajador y en el fortalecimiento de la cultura organizacional.

  17. para su puesta en marcha

    Directory of Open Access Journals (Sweden)

    Sergio Franco Maass

    2004-01-01

    Full Text Available Los sistemas de información geográfica (SIG tienen una gran aplicación en la gestión municipal; permiten cumplir con dos objetivos fundamentales: el registro de información territorial y el análisis de problemas territoriales específicos. Con el fin de determinar la viabilidad de este tipo de tecnologías en el ámbito municipal, se enfrentó el problema de la localización de instalaciones para la disposición final de residuos sólidos urbanos en el municipio de Toluca, Estado de México. Se identifican ciertos aspectos que limitan la práctica de los SIG: la diversidad entre los municipios, los problemas administrativos, las deficiencias de la información y la carencia de recursos humanos, técnicos y financieros.

  18. HeatTransfer Coefficients and Pressure Drops of The Finned Tube Heat Exchangers with Small Diameter Pipes

    Science.gov (United States)

    Tanaka, Hiroyoshi; Aoyama, Shigeo; Koma, Hachirou; Adachi, Masaaki

    In order to enhance the heat transfer coefficient of the fin used in the finned tube heat exchanger, newly designed fin surfaces, especially, with small diameter (≅4mm) pipes are developed. The experiments are made by the transient testing technique, and used the plastic fins scaling up 4 times of the actual metal fin size. The data of the heat transfer coefficient and the pressure drop are transformed to the actual metal fin data. The fin with the anomalous staggered pipe arrangement and the bridge-like cutting-out with inclined leg portion from stream line is found to have very high overall heat transfer coefficient which is about 1.8-fold increase in comparison with the conventional Louvered fin. In this paper the reason why such enhancement is caused is clarified by mean of the calculation based on the rectangular duct flow. The calculated values are coincident with the data of the experiment well.

  19. Novel concepts and geometries as alternatives to conventional circular pin fins for gas turbine blade cooling applications

    Science.gov (United States)

    Uzol, Oguz

    Short cylindrical pin fins with circular cross-sections are one of the most common types of cooling devices used in turbine blades. However it is by no means clear that the circular shape is the most efficient geometry in terms of heat transfer enhancement and pressure loss minimization. Therefore, novel pin fin concepts and geometries are developed and introduced as alternatives to conventional circular pin fins. The idea of using fluidic oscillators as turbulent heat transfer enhancement devices led to the novel concept of "oscillator fin". Also the idea of using more elliptical fin shapes resulted in the development of the SEF (Standard Elliptical Fin), the N fin (Derived from NACA four-digit series of airfoils) and the Egg fin (A hybrid circular-elliptical fin). Detailed experimental and computational investigations are performed in order to determine the heat transfer and pressure loss characteristics of these new concepts and the results are compared to the characteristics of conventional circular pin fins. The experimental analysis included endwall convective heat transfer coefficient measurements, wake total pressure surveys and wake flow field measurements and visualizations using particle image velocimetry (PIV). The isolated single fin measurements revealed that the oscillator fin concept is not working as expected and does not provide any advantage over circular fins. The SEFs and the N fins were found to be the most effective cooling devices in terms of both heat transfer enhancement and pressure loss minimization. The characteristics of the SEF and N fins are also determined for a 2 row staggered array configuration. It is observed that the endwall heat transfer enhancement capability of the SEFs and the N fins is about 25% less than the circular fins. However these elliptical fins caused tremendous reduction in loss levels from 100% to 200%. The main reason of this high levels of pressure loss in circular fin arrays is determined to be the huge low

  20. Calling behavior of blue and fin whales off California

    Science.gov (United States)

    Oleson, Erin Marie

    Passive acoustic monitoring is an effective means for evaluating cetacean presence in remote regions and over long time periods, and may become an important component of cetacean abundance surveys. To use passive acoustic recordings for abundance estimation, an understanding of the behavioral ecology of cetacean calling is crucial. In this dissertation, I develop a better understanding of how blue (Balaenoptera musculus) and fin (B. physalus ) whales use sound with the goal of evaluating passive acoustic techniques for studying their populations. Both blue and fin whales produce several different call types, though the behavioral and environmental context of these calls have not been widely investigated. To better understand how calling is used by these whales off California I have employed both new technologies and traditional techniques, including acoustic recording tags, continuous long-term autonomous acoustic recordings, and simultaneous shipboard acoustic and visual surveys. The outcome of these investigations has led to several conclusions. The production of blue whale calls varies with sex, behavior, season, location, and time of day. Each blue whale call type has a distinct behavioral context, including a male-only bias in the production of song, a call type thought to function in reproduction, and the production of some calls by both sexes. Long-term acoustic records, when interpreted using all call types, provide a more accurate measure of the local seasonal presence of whales, and how they use the region annually, seasonally and daily. The relative occurrence of different call types may indicate prime foraging habitat and the presence of different segments of the population. The proportion of animals heard calling changes seasonally and geographically relative to the number seen, indicating the calibration of acoustic and visual surveys is complex and requires further study on the motivations behind call production and the behavior of calling whales

  1. Edificio sustentable de oficinas para venta.

    OpenAIRE

    Carranza Cabrera, Ramiro Alejandro

    2012-01-01

    Un inversionista, propietario de un terreno ubicado en el centro financiero de San Isidro, ha solicitado a la empresa realizar un estudio de factibilidad técnica y económica, con el fin de verificar la viabilidad de ejecutar un proyecto de inversión de corto plazo, de un edificio de oficinas para su venta (con el valor agregado de obtener la certificación LEED), debido a la tendencia actual que tiene el mercado inmobiliario en el sector de oficinas prime A y A+, considerando...

  2. Controlador de gastos para dispositivos Android

    OpenAIRE

    2012-01-01

    Este proyecto fin de carrera consiste en desarrollar una aplicación Android gestora de las finanzas personales que permita llevar un control exhaustivo de nuestros gastos y nuestros ingresos. Para poder diversificar cada una de las transacciones se han establecido diversos conceptos como cuentas, categorías o localizaciones. Las cuentas, así como las transacciones, son parte fundamental de la aplicación pues con ellas se establece una separación de nuestras finanzas. Las localizaciones, po...

  3. Música para bebés

    OpenAIRE

    Cala Guerrero, María Dolores

    2014-01-01

    Este trabajo fin de grado refleja una revisión bibliográfica sobre la importancia que tiene el tratamiento de la música en madres embarazadas y bebés, para ello se investiga y se toman como ejemplo las aportaciones de los autores más relevantes en este tema. Se realiza un estudio sobre los beneficios de una correcta educación musical en edades tempranas y cómo ésta afecta al desarrollo psicomotor, cognitivo, emocional y lingüístico. Se habla sobre la importancia de conectar musicalmente a ...

  4. 新加坡FinTech生态系统建设及其启示%Singapore’s FinTech Ecological System Construction and Its Enlightenment

    Institute of Scientific and Technical Information of China (English)

    钟鸣长

    2016-01-01

    Since the financial crisis, the integration of finance and technology has become a new trend in global economic development, and become a hot issue in the political, business, and academic attention. Singapore government maps out a strategy and introduces a series of policies to build FinTech ecosystem, such as financial support, establishing FinTech SUB, and implementing regulatory sandbox. Thus, Singapore will transform the existing financial system, construct the FinTech hub, and become an intelligent country of S&T and intelligent financial center. However, Internet finance in China is still at the stage of FinTech1.0 currently, which appears to be fast, slant, and disordered. So it is urgent to be transformed and upgraded. Meanwhile, we should not only be fully aware of the necessity and urgency of FinTech ecosystem development, clarify the relation between Internet financial and FinTech, but also we should learn from Singapore’s advanced experience to develop the FinTech ecosystem in all aspects, for example, setting up specialized management institutions, determining specific development goals, providing financial support, promoting “Regulatory Sandbox”, mobilizing domestic and international market resources, and exerting the role of the government, market, and enterprises.%金融危机以来,金融与科技的融合成为全球经济发展的一股新潮流和趋势,成为政、商、学界关注的热点话题。新加坡从资金支持、搭建创业加速平台、推行监管沙盒等方面推出了打造FinTech生态系统的组合拳,旨在改造现有金融体系、建设FinTech枢纽中心,立志成为世界智慧科技大国和智慧金融中心。中国互联网金融目前总体上还处于FinTech1.0阶段,呈现一种“快、偏、乱”的现象,亟需转型与升级。因此,我们不仅要充分意识到FinTech产业发展的必要性和紧迫性,厘清互联网金融与FinTech的关系,而且要学习和借鉴新加

  5. A method for numerically simulating the thermal state of a tube with punched helical-tape finning

    Science.gov (United States)

    Galushchak, I. V.; Gorbatenko, V. Ya.; Shevelev, A. A.

    2011-05-01

    A method for numerically simulating the thermal state of a tube with punched helical-tape finning and heat transfer from heating to heated medium through the finned tube is presented. Results of calculations carried out for one version of finning geometry under the conditions of heating nonboiling water by flue gases are given.

  6. Dynamic stiffness testing-based flutter analysis of a fin with an actuator

    Institute of Scientific and Technical Information of China (English)

    Zhang Renjia; Wu Zhigang; Yang Chao

    2015-01-01

    Engineering-oriented modeling and synthesized modeling of the fin-actuator system of a missile fin are introduced, including mathematical modeling of the fin, motor and multi-stage gear reducer. The fin-actuator model is verified using dynamic stiffness testing. Good agreement is achieved between the test and theoretical results. The parameter-variable analysis indicates that the inertia of the motor rotor, reduction ratio of the reducer, connection stiffness and damping between the actuator and fin shaft have significant impacts on the dynamic stiffness characteristics. In flutter analysis, test data are directly used in the frequency domain method and indirectly used in the time domain method through the updated fin-actuator model. The two methods play different roles in engineering applications but are of equal importance. The results indicate that dynamic stiffness and constant stiffness treatments may lead to completely different flutter characteristics. Attention should be paid to the design of the fin-actuator system of a missile.

  7. Cdk and APC activities limit the spindle-stabilizing function of Fin1 to anaphase.

    Science.gov (United States)

    Woodbury, Erika L; Morgan, David O

    2007-01-01

    The fidelity of chromosome segregation depends on proper regulation of mitotic spindle behaviour. In anaphase, spindle stability is promoted by the dephosphorylation of cyclin-dependent kinase (Cdk) substrates, which results from Cdk inactivation and phosphatase activation. Few of the critical Cdk targets have been identified. Here, we identify the budding-yeast protein Fin1 (ref. 7) as a spindle-stabilizing protein whose activity is strictly limited to anaphase by changes in its phosphorylation state and rate of degradation. Phosphorylation of Fin1 from S phase to metaphase, by the cyclin-dependent kinase Clb5-Cdk1, inhibits Fin1 association with the spindle. In anaphase, when Clb5-Cdk1 is inactivated, Fin1 is dephosphorylated by the phosphatase Cdc14. Fin1 dephosphorylation targets it to the poles and microtubules of the elongating spindle, where it contributes to spindle integrity. A non-phosphorylatable Fin1 mutant localizes to the spindle before anaphase and impairs efficient chromosome segregation. As cells complete mitosis and disassemble the spindle, the ubiqutin ligase APC(Cdh1) targets Fin1 for destruction. Our studies illustrate how phosphorylation-dependent changes in the behaviour of Cdk1 substrates influence complex mitotic processes.

  8. Experimental Analysis Of Heat Transfer From Square Perforated Fins In Staggered Arrangement

    Directory of Open Access Journals (Sweden)

    Siddiqui. M. Abdullah

    2015-08-01

    Full Text Available This project gives the experimental analysis of heat transfer over a flat surface equipped with Square perforated pin fins in staggered arrangement in a rectangular channel. The Fin dimensions are 100mm in height & 25mm in width. The range of Reynolds number is fixed & about 13,500– 42,000, the clearance ratio (C/H 0, 0.33 and 1, the inter-fin spacing ratio (Sy /D 1.208, 1.524, 1.944 and 3.417. Sy i.e. stream wise distance is varies and Sx i.e. span wise distance is constant. The friction factor, enhancement efficiency and heat transfer correlate in equations with each other. Here we are comparing Square pin fins with cylindrical pin fins. Staggered arrangement and perforation will enhance the heat transfer rate. Clearance ratio and inter-fin spacing ratio affect on Enhancement efficiency. Both lower clearance ratio and lower inter-fin spacing ratio and comparatively lower Reynolds number give higher thermal performance. Friction factor & Nusselt number are Key parameter which relates with efficiency enhancement and heat transfer rate.

  9. A porosity model for flow resistance calculation of heat exchanger with louvered fins

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Taek Keun [Halla Visteon Climate Control Corp. Daejeon (Korea, Republic of); Kang, Hie Chan [Kunsan National University, Gunsan (Korea, Republic of); Lee, Joon Sik [Seoul National University, Seoul (Korea, Republic of)

    2016-04-15

    A full 3-dimensional flow simulation of a louvered fin heat exchanger assembly requires a huge number of grid points and enormous computing time. This work proposes a porous media model for the flow resistance calculation of the louvered fin side in order to efficiently simulate a complex 3-dimensional flow over the louvered fins. In the present model, we determine the permeability and Ergun constant in the modified Darcy equation. We first build up a database of the friction factor from the available experimental data and our own CFD data, and then develop the friction factor correlation in the range of the Reynolds number based on the louver pitch from 0.001 to 20000 for 14 different louvered fin types. We use the non-linear and multi-linear regression analyses to obtain the friction factor correlation as a function of louvered fin geometric parameters such as louver pitch, louver angle and fin pitch. The present friction factor correlation shows an excellent agreement with the previous experimental and CFD data. The modified Darcy equation with the proposed permeability and Ergun constant for the louvered fin side can easily be coupled with the 3-dimensional computation of the main tube flow.

  10. Characteristics of a micro-fin evaporator: Theoretical analysis and experimental verification

    Directory of Open Access Journals (Sweden)

    Zheng Hui-Fan

    2013-01-01

    Full Text Available A theoretical analysis and experimental verification on the characteristics of a micro-fin evaporator using R290 and R717 as refrigerants were carried out. The heat capacity and heat transfer coefficient of the micro-fin evaporator were investigated under different water mass flow rate, different refrigerant mass flow rate, and different inner tube diameter of micro-fin evaporator. The simulation results of the heat transfer coefficient are fairly in good agreement with the experimental data. The results show that heat capacity and the heat transfer coefficient of the micro-fin evaporator increase with increasing logarithmic mean temperature difference, the water mass flow rate and the refrigerant mass flow rate. Heat capacity of the micro-fin evaporator for diameter 9.52 mm is higher than that of diameter 7.00 mm with using R290 as refrigerant. Heat capacity of the micro-fin evaporator with using R717 as refrigerant is higher than that of R290 as refrigerant. The results of this study can provide useful guidelines for optimal design and operation of micro-fin evaporator in its present or future applications.

  11. Assessment of in vitro antifungal activity of preparation ''fin Candimis'' against Candida strains

    Directory of Open Access Journals (Sweden)

    Anna Głowacka

    2013-12-01

    Full Text Available The aim of the study was to assess the antifungal activity of preparation „fin Candimis” (oregano essential oil against yeast-like strains belonging to the genus Candida. During the investigation, there were used up nine Candida albicans strains and ten C. glabrata strains isolated from different clinical material, along with one C. albicans demonstration strain ATCC 90028. The oregano essential oil, utilized in the study, was obtained from fresh leaves of Origanum vulgare L. and bore a trade name „fin Candimis”. According to data yielded by its manufacturer, concentration of pure oregano essential oil in preparation „fin Candimis” totals up to 210 mg/ml. The susceptibility of the Candida strains to preparation „fin Candimis” was assessed by means of the disc-diffusion method, upon the Sabouraud solid medium (after a 24-hour incubation of the cultures at temperature of 37 degrees centigrade; the oregano essential oil had been diluted in 1 ml of DMSO, according to the geometrical progression. A measure of the antifungal activity of preparation „fin Candimis” was the minimal inhibitory concentration (MIC, in terms of the fungus growth. Preparation „fin Candimis” is capable of being applied in the prevention and treatment of candidiasis – alone, or as a natural adjunctive agent. The C. albicans strains are more susceptible to preparation „fin Candimis” in comparison to the C. glabrata ones.

  12. Aryl hydrocarbon receptor activation impairs extracellular matrix remodeling during zebra fish fin regeneration.

    Science.gov (United States)

    Andreasen, Eric A; Mathew, Lijoy K; Löhr, Christiane V; Hasson, Rachelle; Tanguay, Robert L

    2007-01-01

    Adult zebra fish completely regenerate their caudal (tail) fin following partial amputation. Exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) inhibits this regenerative process. Proper regulation of transcription, innervation, vascularization, and extracellular matrix (ECM) composition is essential for complete fin regeneration. Previous microarray studies suggest that genes involved in ECM regulation are misexpressed following activation of the aryl hydrocarbon receptor. To investigate whether TCDD blocks regeneration by impairing ECM remodeling, male zebra fish were i.p. injected with 50 ng/g TCDD or vehicle, and caudal fins were amputated. By 3 days postamputation (dpa), the vascular network in the regenerating fin of TCDD-exposed fish was disorganized compared to vehicle-exposed animals. Furthermore, immunohistochemical staining revealed that axonal outgrowth was impacted by TCDD as early as 3 dpa. Histological analysis demonstrated that TCDD exposure leads to an accumulation of collagen at the end of the fin ray just distal to the amputation site by 3 dpa. Mature lepidotrichial-forming cells (fin ray-forming cells) were not observed in the fins of TCDD-treated fish. The capacity to metabolize ECM was also altered by TCDD exposure. Quantitative real-time PCR studies revealed that the aryl hydrocarbon pathway is active and that matrix-remodeling genes are expressed in the regenerate following TCDD exposure.

  13. Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method

    Directory of Open Access Journals (Sweden)

    Ningyu Li

    2016-01-01

    Full Text Available Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis.

  14. Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method.

    Science.gov (United States)

    Li, Ningyu; Su, Yumin

    2016-01-01

    Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB) method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis.

  15. Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary Method

    Science.gov (United States)

    Li, Ningyu; Su, Yumin

    2016-01-01

    Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary (IB) method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis. PMID:27478363

  16. The Oldest Actinopterygian Highlights the Cryptic Early History of the Hyperdiverse Ray-Finned Fishes.

    Science.gov (United States)

    Lu, Jing; Giles, Sam; Friedman, Matt; den Blaauwen, Jan L; Zhu, Min

    2016-06-20

    Osteichthyans comprise two divisions, each containing over 32,000 living species [1]: Sarcopterygii (lobe-finned fishes and tetrapods) and Actinopterygii (ray-finned fishes). Recent discoveries from China highlight the morphological disparity of early sarcopterygians and extend their origin into the late Silurian [2-4]. By contrast, the oldest unambiguous actinopterygians are roughly 30 million years younger, leaving a long temporal gap populated by fragments and rare body fossils of controversial phylogenetic placement [5-10]. Here we reinvestigate the enigmatic osteichthyan Meemannia from the Early Devonian (∼415 million years ago) of China, previously identified as an exceptionally primitive lobe-finned fish [3, 7, 11, 12]. Meemannia combines "cosmine"-like tissues taken as evidence of sarcopterygian affinity with actinopterygian-like skull roof and braincase geometry, including endoskeletal enclosure of the spiracle and a lateral cranial canal. We report comparable histological structures in undoubted ray-finned fishes and conclude that they are general osteichthyan features. Phylogenetic analysis places Meemannia as an early-diverging ray-finned fish, resolving it as the sister lineage of Cheirolepis [13] plus all younger actinopterygians. This brings the first appearance of ray-fins more in line with that of lobe-fins and fills a conspicuous faunal gap in the otherwise diverse late Silurian-earliest Devonian vertebrate faunas of the South China Block [4]. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  17. Design, Implementation and Control of a Fish Robot with Undulating Fins

    Directory of Open Access Journals (Sweden)

    Mohsen Siahmansouri

    2011-11-01

    Full Text Available Biomimetic robots can potentially perform better than conventional robots in underwater vehicle designing. This paper describes the design of the propulsion system and depth control of a robotic fish. In this study, inspired by knife fish, we have designed and implemented an undulating fin to produce propulsive force. This undulating fin is a segmental anal fin that produces sinusoidal wave to propel the robot. The relationship between the individual fin segment and phase angles with the overall fin trajectory has also been discussed. This propulsive force can be adjusted and directed for fish robot manoeuvre by a mechanical system with two servomotors. These servomotors regulate the direction and depth of swimming. A wireless remote control system is designed to adjust the servomotors which enables us to control revolution, speed and phase differences of neighbor servomotors of fins. Finally, Field trials are conducted in an outdoor pool to demonstrate the relationship between robotic fish speed and fin parameters like phase difference, the number of phase and undulatory amplitude.

  18. Computational Study on a Squid-Like Underwater Robot with Two Undulating Side Fins

    Institute of Scientific and Technical Information of China (English)

    Md. Mahbubar Rahman; Yasuyuki Toda; Hiroshi Miki

    2011-01-01

    The undulating fin propulsion system is an instance of the bio-inspired propulsion systems. In the current study, the swimming motion of a squid-like robot with two undulating side fins, mimicking those of a Stingray or a Cuttlefish, was investigated through flow computation around the body. We used the finite analytic method for space discretization and Euler implicit scheme for time discretization along with the PISO algorithm for velocity pressure coupling. A body-fitted moving grid was generated using the Poisson equation at each time step. Based on the computed results, we discussed the features of the flow field and hydrodynamic forces acting on the body and fin. A simple relationship among the fin's principal dimensions was established. Numerical computation was done for various aspect ratios, fin angles and frequencies in order to validate the proposed relationship among principal dimensions. Subsequently, the relationship was examined base on the distribution of pressure difference between upper and lower surfaces and the distribution of the thrust force. In efficiency calculations, the undulating fins showed promising results. Finally, for the fin, the open characteristics from computed data showed satisfactory conformity with the experimental results.

  19. Pectoral fins aid in navigation of a complex environment by bluegill sunfish under sensory deprivation conditions.

    Science.gov (United States)

    Flammang, Brooke E; Lauder, George V

    2013-08-15

    Complex structured environments offer fish advantages as places of refuge and areas of greater potential prey densities, but maneuvering through these environments is a navigational challenge. To successfully navigate complex habitats, fish must have sensory input relaying information about the proximity and size of obstacles. We investigated the role of the pectoral fins as mechanosensors in bluegill sunfish swimming through obstacle courses under different sensory deprivation and flow speed conditions. Sensory deprivation was accomplished by filming in the dark to remove visual input and/or temporarily blocking lateral line input via immersion in cobalt chloride. Fish used their pectoral fins to touch obstacles as they swam slowly past them under all conditions. Loss of visual and/or lateral line sensory input resulted in an increased number of fin taps and shorter tap durations while traversing the course. Propulsive pectoral fin strokes were made in open areas between obstacle posts and fish did not use the pectoral fins to push off or change heading. Bending of the flexible pectoral fin rays may initiate an afferent sensory input, which could be an important part of the proprioceptive feedback system needed to navigate complex environments. This behavioral evidence suggests that it is possible for unspecialized pectoral fins to act in both a sensory and a propulsive capacity.

  20. Thermal Efficiency of Double Pass Solar Collector with Longitudinal Fins Absorbers

    Directory of Open Access Journals (Sweden)

    Ahmad Fudholi

    2011-01-01

    Full Text Available Problem statement: One of the most important components of a solar energy system is the solar collector. The performances of double-pass solar collector with longitudinal fins absorbers are analyzed. Approach: The study involves a theoretical study to investigate the effect of mass flow rate, number and height of fins on efficiency, which involves steady-state energy balance equations on the longitudinal fins absorber of solar collectors. The theoretical solution procedure of the energy equations uses a matrix inversion method and making some algebraic rearrangements. Results: The collector efficiency increases as the number and height of fins increases. For a mass flow rate 0.02- 0.1kg/s, the double-pass solar collectors are efficiency about 36-73% in upper fins (type I, 37-75% in lower fins (type II and 46-74% in upper and lower fins (type III. Conclusion: The efficiency of the collector is strongly dependent on the flow rate, efficiency increase is about 35%.